PLATINUM METALS REVIEW...ic HC ter WET DIESEL EXHAUST DRY DIESEL EXHAUST Fig. 1 The compositions are...

UK ISSN 0032-1400

PLATINUM METALS REVIEW

A quarterly survey of research on the platinum metals and of developments in their application in industry

VOL. 35 OCTOBER 1991

Contents

Flow-Through Catalysts for Diesel Engine Emissions Control

Royal Commission Report on Diesel Emissions

Chemical Reaction Fronts on Platinum Surfaces

Platinum Catalyses the Conversion of Methane to Higher Alkanes

Metal-Hydrogen Systems

The Plastic Flow of Iridium

Ammonia Sensor Uses Platinum Films

Partners in Innovation Conference

Recovery of Platinum Group Metals from High Level Radioactive Waste

Platinum Silicide Temperature Detectors

Palladium Contact Materials

Second Grove Fuel Cell Symposium

Michael Faraday and Platinum

Abstracts

New Patents

Index to Volume 35

NO. 4

178

187

188

195

195

196

200

20 1

202

208

208

209

222

228

24 1

250

Communications should be addressed to The Editor, Platinum Metals Review

Johnson Matthey Public Limited Company, Hatton Garden, London ECl N 8EE

Flow-Through Catalysts for Diesel Engine Emissions Control PLATINUM COATED MONOLITHS REDUCE PARTICULATES

By B. J. Cooper and S. A. Roth Johnson Matthey, Catalytic Systems Division, Wayne, Pennsylvania

The treatment of vehicle emissions with an exhaust catalyst in order to reduce the level of three major air pollutants, namely carbon monoxide, unburnt hydrocarbons and nitrogen oxides, is becoming a world-wide requirement for gasoline fuelled engines (1, 2). First standards were introduced in the U.S.A. and Japan during the early 1970s (3). Similar standards will be enforced in Europe beginning in 1992/93 (4, 5). Diesel engine exhaust poses an additional challenge for emission control because, as compared to exhaust from gasoline engines, it also contains particulate matter. Ear- ly attempts at particulate control utilised catalytic trap oxidisers to filter the exhaust and oxidise the particulates (6-8). Catalytic trap oxidisers have the disadvantage of requiring an active regeneration mechanism to remove particulate build-up. Recent advances in diesel

engine technology have greatly reduced the formation of particulates, with the result that air quality standards may now be met by the use of catalysed flow-through monoliths (9-1 1). These catalysts have the advantage of being passive systems which do not require regeneration.

Catalysts for diesel engines must function dif- ferently to those for gasoline engines because of differences in the chemical composition of the exhaust gas. Modern spark-ignition gasoline powered automobiles, with emission control devices, operate near stoichiometry (at an airfuel ratio of - 14.7: 1) and under closed-loop electronic control. The catalyst typically operates in the temperature range of 300 to 9OOOC and functions by oxidising carbon monoxide and unburnt hydrocarbons to carbon dioxide and water, while oxides of nitrogen are

Cal

ic

HC

ter

W E T DIESEL EXHAUST DRY DIESEL EXHAUST

Fig. 1 The compositions are given of typical particulates collected from the exhaust of diesel engines characterised using the European hot star t Extra Urban Driving Cycle. The hydrocarbons derived from both the fuel and the lubrication oil constitute the soluble organic fraction, a high proportion of which indicates a “wet particulate”, while a high proportion of carbon occurs in a “dry particulate”

Platinum Metals Rev., 1991, 35, (4), 178-187 178

Table I

Current and Proposed World-wide Diesel Emission Laws

HD

_" 0.39"

1.1

HC +NO,

HD

I Market [ Test

1.1

co

3.4

NO,

1 .o

Particulate

0 .20 U.S. FTP I 1987 I glmile

7.0 0 . 4 0.08 California glmile

1991 HD I 1.3 0.25 15.5

15.5

5 .0

5 .0 0 .10 U.S. H DT 1994 glhph

Japan 1 0 Mode 1990 glkm

Japan 1 0 Mode 1994 glkm

EC ECE+EUDC 1992 glkm

2.70 2.70

0.70 0.84

None None

f I::: 0.50 0.60

0.2 0.2

2.70 2.70

2.72 0.97 0.14

1 EC proposed

Stage 1 1992193

Stage 2 1995196

EC steady state test

glkWh

EC steady state test

glkWh

4.5

4.0

-

8.0

7.0

-

0.36

0.15

FTP Federal Test Procedure LD light duty HDT Heavy Duty Truck HD heavy duty EUDC Extra Urbm Driving Cyle

reduced to nitrogen gas (12-16). The standard practice for gasoline exhaust treatment is to utilise a noble metal catalyst supported on a flow-through ceramic or metallic monolith, typically having 300 to 400 axial channels per square inch of frontal area. The monolith walls are coated with a thermally durable, high surface area oxide on which are supported the active catalyst components, generally platinum, palladium and rhodium.

Combustion of diesel fuel occurs by high pressure ignition, raker than by spark ignition, and at air:fuel ratios greater than 20:l. The

* Non methane hydrocarbons

exhaust temperatures are typically cooler, 150 to 450°C, and are always oxidising. The diesel engine generates intrinsically low emission levels of gas phase hydrocarbons and carbon monoxide, and when fitted with a conventional oxidation catalyst there is little trouble meeting regulated standards for these pollutants. The use of typical three-way catalysts to control nitrogen oxide emissions is impractical due to the oxidising nature of the exhaust. Therefore, nitrogen oxide emissions must be controlled by engine design and calibration, often at the expense of increased particulate emissions. As a

Platinum Metals Rev., 1991, 35, (4) 179

California FTP 1989 glmile

U.S. H DT 1991 glhph

U.S. H DT 1994 glhph

Japan 10 Mode 1 glkm 1 !: 1 !!!: 1990

Japan 10 Mode 1994 g/km HD 0.62

LD 0.39"

HD 1.3

HD 1.3

EC 1992

ECE+EUDC Auto glkm

Fig. 2 In the absence of platinum, the pressure drop across a catalyst monolith varies with time, due to progressive obstruction of the axial passages by the build- up of carbon particulates

TEST TIME ON ENGINE, hours

result, the major challenge to diesel exhaust emission control by catalytic means remains one of particulate removal. Additionally, in Europe, where there is a combined hydrocarbon + nitrogen oxide standard, removal of low temperature gas phase hydrocarbons is beneficial to meeting the overall design requirements.

There are a variety of diesel engine designs and these may be classified according to the method of fuel and air injection, as well as by the end-use application. Engines with indirect injection of fuel are typically utilised for passenger cars and light-duty trucks, while direct injection engines have inherently better fuel economy and are utilised in heavy duty vehicles. Many manufacturers are developing high speed direct injection engines for use in light-duty applications. Air is added to the combustion chamber by natural aspiration or under pressure by turbocharging, and turbocharging is often accompanied by intercool- ing. World-wide emissions standards for diesel fuelled engines will finally require the use of catalytic converters in the 1992-94 time frame, see Table I.

Diesel Particulate Catalysis Particulate Composition

Diesel particulate standards are measured via the weight increase of a fibre fiter placed in the diesel exhaust. The material collected consists of graphitic “hard” carbon or “soot”, a soluble organic fraction (SOF), water, sulphuric acid and an inorganic ash residue. Typical particulate compositions are given in Figure 1. The

soluble organic fraction consists of hydrocarbons derived from both fuel and lubricating oil which condense as the exhaust cools, or adsorb during collection. The sulphuric acid/water fraction arises from oxidation of sulphur dioxide to sulphur trioxide and condensation with water vapour.

Importance of Sulphur in Diesel Particulate Control

Sulphur is present to some extent in all diesel fuel and, as a result of the combustion process, is emitted in the exhaust as sulphur dioxide. A small fraction, typically about 2 per cent, is further olddised to sulphur trioxide which con- denses with water in the exhaust as sulphuric acid, and is then absorbed on carbonaceous soot particles, thus contributing to the total measured mass of particulate emissions. The use of a catalyst can increase the fraction of fuel sulphur converted to sulphate, and even a modest increase in this fraction will result in the “manufacture” of significant particulate. For example for a 0.05 weight per cent sulphur fuel, 100 per cent conversion of the sulphur in the fuel to sulphuric acid would by itself result in a particulate emission five times higher than the 1994 U.S. heavy duty truck standard.

Particulate Control Strategy A “flow-through’’ monolithic reactor, as op-

posed to a particulate trap, achieves particulate reduction by catalytic oxidation of the soluble organic fraction. However, this will result in minimal conversion of the hard carbon, and therefore, the catalyst must be able to keep


itself free from particulate fouling. During low temperature operation particulate increase via sulphuric acid formation is not significant, but under these low temperature conditions it is necessary for the catalyst to remove the soluble organic fraction and the gas phase hydrocarbons. During high temperature operation the oxidation of hydrocarbon is facile, but the increase of particulates due to sulphate formation must be minimised or eliminated.

Catalytic Carbon Oxidation It has been reported previously that the

removal of carbon requires reaction with nitrogen dioxide, which is formed by the oxidation of nitrogen monoxide over a platinum catalyst (17). Palladium and rhodium are much less effective for the oxidation of nitrogen monoxide at low temperatures, and their inclusion with platinum in a catalyst formulation results in de-activation of the platinum. In the absence of platinum an increase in back pressure in a flow-through system has been observed as a function of time, see Figure 2. This emphasises the requirement for platinum in the catalyst formulation in order to prevent fouling by carbon particulate.

Catalytic Sulphur Oxidation Similar to carbon oxidation, it has been

demonstrated that platinum is the most effective catalyst for sulphur dioxide oxidation, that palladium and rhodium are less active, and that the alloying of palladium or rhodium with platinum results in a compromise activity.

Sulphur dioxide adsorbs strongly on platinum at room temperature and inhibits carbon monoxide, nitrogen monoxide and alkene oxidation. Sulphur dioxide oxidation is kinetically limited at low temperature and thermodynamically limited at high temperature, but near 500 to 6OOOC can reach 80 to 90 per cent conversion. Factors which can limit sulphur dioxide oxidation activity in this temperature range include oxygen concentration, space velocity (Figure 3), and intrinsic catalytic activity.

Removal of the Soluble Organic Fraction

Hydrocarbon species in diesel exhaust consist of gaseous compounds as well as heavy, con- densable hydrocarbons (soluble organic fraction) which can be solubilised from the diesel particulate. The soluble organic fraction is both fuel and oil derived, and has been characterised by gas chromatography-mass spectroscopy (18, 19). As with the oxidation of sulphur dioxide and nitrogen monoxide, platinum is generally considered the best low temperature hydrocarbon oxidation catalyst, with palladium or rhodium being both less effective and/or poisons for platinum. At high temperatures complete oxidation is favoured.

Emission Characteristics of Diesel Engines

To demonstrate the variability in emission composition with engine type and operating conditions, test results for two diesel engines

p 100 U a

Fig. 3 The degree of oxida- Bo tion of sulphur dioxide over a platinised monolith catalyst is influenced by a number of 6o

factors including the u operating temperature and 4 4 0

the space velocity; the latter x is shown in this Figure as K, 2o

and is measured in units of 5 thousands of reciprocal 5 2 50 300 350 4w 450 500

3 hours INLET TEMPERATURE, 'C


Table II

Baseline Diesel Emissions*

Test

FTP glmile

EUDC gltest

Hot SS gltest

Engine" " HC co NO, Particulate

A 0.18 0.64 0.96 0.24 B 0.13 0.81 0.76 0.16

A 0.51 1.67 3.31 0.95 B 0.42 2.02 2.89 0.75

A 1.87 5.72 12.2 2.79 B 0.86 5.54 7.95 2.27

* lmean of triplicate testing1 * * Engine A: 1.6 I IDI-TC indirect injection-turbocharging

Engine 6 : 1.8 I IDI-NA indirect injection-natural aspiration

SS steady-state

Compound

Methane Ethylene Acetylene Propylene 1 -Butene lsobutene 1,3-Butadiene Benzene Toluene Ethyl benzene p- and m-Xylene o-Xylene

Formaldehyde Acetaldehyde Acrolein Acetone Propionaldehyde Crotonaldehyde Benzaldehyde

Tabla 111

Baseline Gaseous Hydrocarbon Emissions

FTP (mglmile)

EUDC (mgltest)

HOT SS (mg/test)

A

48.2 27.4 7.3 11.5 -9 -9 5.6

-4 -6

-15 - 23 - 16 15.2 8.5 3.0 2.5 3.0 0.7 2.5

B

105 26.8 10.6 8.4 7.5 6.7 9.4 7.1 11.7 15.7 42.2 19.8

33.3 30.4 8.1 5.6 2.9 2.6 5.3

Engine

A

109 68.5 21.2 27.8

- 20 - 23 14.8

-12 - 34 - 34 -115 - 28 59.3 55.1 11.2 13.9 8.3 2.7 8.5

B

2 20 60.2 25.6 23.6 12.7 13.3 14.5 18.4 19.5 34.7 67.6 23.4

152 119 26.9 10.6 6.2 5.2 12.8

A

31 5 346 67.8 145 - 65

- 145 79.2

- 29 - 36

-135 - 78

- 1 1 1

210 105 53.7 37.3 20.5 16.3 34.6

B

594 148 69.5 65.8 12.3 48.7 18.0 51.2 33.4 90.0 143 133

166 155 34.8 13.4 6.9 10.0 24.1


Table IV

Baseline Particulate Emissions

Sulphate 1 t: I i: I SOF ~ Carbon 1 + Water 1 Other Fuel

HC Other

Sulphate + Water

Carbon SOF Oil HC

are given in Table I1 (20). The engines were characterised using the U.S. cold start Federal Test Procedure, the European hot start Extra Urban Driving Cycle and a hot steady-state test with inlet temperature in the range of 400 to 420OC. The emitted gaseous components and particulates measured without a catalyst fitted to the engines are given.

The gaseous hydrocarbon fraction resulting from incomplete fuel combustion was analysed in further detail and, as shown in Table 111, was composed primarily of methane, and unsaturated, cyclic and oxygenated hydrocarbons. The aldehydeketone components are generally considered to be responsible for the offensive odour associated with diesel engine exhaust.

The composition of the particulate component of diesel emissions is dependent on the combustion process, as controlled by engine design, the lubricant and the fuel used. The sulphate content was analysed by ion chromatography, the soluble organic fraction

Engine A 7.0 22.4 29.4 40.4 2.0 Engine B 16.9 6.4 23.3 63.7 2.6

was extracted and subsequently characterised into fuel derived and oil derived fractions by gas chromatography, and the carbon content was quantified by thermogravimetric analysis. The remaining component has not been fully characterised, but represents the inorganic zinc, calcium, and iron compounds derived from lubricants and from engine wear. The particulate analyses, for all three vehicle test cycles, are shown in Table IVY and illustrate some specific engine characteristics which are important when designing a catalyst for particulate attenuation control.

Engine A showed a consistently higher soluble organic fraction and would be considered to produce a “wet particulate”, with low carbon content and high soluble organic fraction. While Engine B could be described as forming a “dry particulate”, low in soluble organic fraction and high in carbon content. The differences in emissions can be partially explained by the differences in operating temperature,

28.2 10.4

Platinum Metals Rev., 1991, 35, (4)

Engine A 29.8 16.2 46.0 36.1 4.2 Engine B 11.4 <1 .o -11.4 79.3 4.7

183

13.7 3.6

Engine A 15.3 16.6 31.9 Engine B 7.0 <1 .o - 7.0

39.5 4.4 24.2 80.2 4.5 7.3

FTP Percentage of total particulate mass

EUDC Percentage of total particulate mass

Hot SS Percentage of total particulate mass

200 2 5 0 300 350 4 2 5 5 0 0

INLET TEMPERATURE, ‘C

=Fuel HC OIIHC m c s r h Solphate water

Fig. 4 Baseline particulate analyses obtained under steady state conditions, the engine load being used to control the operating temperature. Engine B produces a “dry particulate”, low in soluble organic fraction and high in carbon content. The former remain8 steady while the carbon and sulphate fractions increase witb temperature

with the hotter engine resulting in a “dryer” particulate. Thus Engine B represents the more difficult system to treat catalytically, and would present the greatest challenge.

Catalyst Development The challenge for diesel catalyst development

is to reduce the gaseous hydrocarbons, carbon monoxide and absorbed soluble organic fraction of the exhaust without increasing the mass of the particulate emissions arising from the formation of sulphates.

Catalyst development was conducted using Engine B fitted to a stand dynamometer (20). The catalysts were evaluated under steady state conditions, using engine load to control the operating temperature. This test was conducted at 2500 RPM using fuel with 0.16 weight per cent sulphur. The system was stabilised at each test point prior to exhaust sampling. Baseline emissions were measured at each temperature, with an uncatalysed substrate in the exhaust system to equalise back-pressure on the engine.

The data in Figure 4 represents the baseline particulate analyses as a function of engine load. For Engine B, which generates a “dry” particulate, with increasing load the soluble

organic fraction remains approximately constant while the carbon and sulphate fractions increase. Figure 5 gives the particulate formation rate when a standard platinum oxidation catalyst is placed in the exhaust system. Ex- cellent removal of the soluble organic fraction is observed with little impact on the “hard” car-

Table V

Test Conditions and Composition of the Synthetic Gas Mixture

Space Velocity: Catalyst Size:

Gas Flow Rate:

Gas component

42,000 per hour 1.0‘’ dia x 2.33” long 20.0 SLPM

Concentration

1000 ppm (C, ) 400 ppm 2 0 0 ppm

12.0 % 4.5 % 4.5 Yo

50 P P ~

Balance


Gas component I C10H22 I NO, co I

Concentration

1000 ppm (C, ) 400 ppm 200 ppm

12.0 % 4.5 % 4.5 Yo

50 P P ~

Balance

c, m 80

P a 5 6 0

2 w 2 4 0

u 3 L 2 20

200 2 5 0 300 350 425 500

INLET TEMPERATURE,*C

=Fuel HC oil HC Cartm Sdlphate water Fig. 5 With a standard platinum oxidation catalyst in the exhaust system there is excellent removal of the soluble organic fraction, but above 3OOOC there is a progressive increase in the amount of sulphate contributing to a large net increase in the amount of particulate formed

bon particulate, however, above 3OOOC pro- gressively larger quantities of sulphate are formed. In spite of the removal of the soluble organic fraction over the catalyst there is actual- ly a large net increase in particulate formation, due to the oxidation of sulphur dioxide and the formation of sulphuric acid.

In view of the clear requirement for reduced sulphur dioxide oxidation, new platinum-based diesel catalyst formulations were developed to reduce the oxidation of sulphur dioxide to sulphur trioxide and to limit the degree of sulphur storage on the catalyst surface. Initial evaluation of developmental catalysts was performed utilising a synthetic gas mixture. Since

hydrocarbons in the soluble organic fraction are typically of high molecular weight, decane (C,oH22) was added to the feed-gas to model the hydrocarbon oxidation requirements of a diesel catalyst. The relevant experimental conditions are given in Table V. Hydrocarbon conversion was measured by flame ionisation detection while sulphur dioxide conversion was monitored by gas chromatography. The test results are given in Figure 6 and show a decrease in sulphur dioxide conversion with the new catalyst formulations. This lower activity is accompanied by a decrease in hydrocarbon oxidation activity.

These new catalyst formulations were then

Fig. 6 The activity of a standard platinum oxidation so- catalyst * and t w o new $ platinum-based catalysts , g 4 0 -

especially formulated for Y diesel fuelled engines are 5 20-

compared for the conversion " of hydrocarbons - and sulphur dioxide - -- 2 0 0 2 50 300 350 400 450 500

INLET TEMPERATURE, *C


503 Fig. 7 W h e n the n e w :: 0- platinum-habed catalybt for-

inulatiom were suhjecled to B a -50. 2- the steady-state tliebel exhauat 0 -100-

particulate control at higher temperatures Has ohwr\ed

m tehl a clear inipro\enieut in -1 50.

h -200.

2 -300. " -2 50-

6 $ -350.

-400-. Platinum catdlyst

150 200 250 300 350 400 450 500 550 i INLET TEMPERATURE, .C

evaluated on Engine B utilising the steady-state diesel exhaust test. An obvious improvement in higher temperature particulate control was observed. However, as predicted in the synthetic gas test, low temperature hydrocarbon activity was somewhat reduced. Dynamometer data for particulate and hydrocarbon conversions are given in Figures 7 and 8, respectively. Significant removal of particulate can be achieved by designing the catalyst to minimise sulphate emissions and prevent fouling by rapid carbon accumulation. Some compromise must be made for gas phase hydrocarbon activity. Although, meeting standards for gas phase hydrocarbon emissions is typically not difficult, some further improvement may be desirable for European light-duty vehicles which must meet a hydrocarbon + nitrogen oxide standard. This is the focus of future efforts in this area.

Conclusions The development of platinum-based catalysts

for the control of diesel engine exhaust requires

a knowledge of the exhaust temperature and the particulate composition. Although these factors are dependent upon individual engine design, the catalyst may be tailored to meet specific requirements.

To meet new regulatory standards a reduction in exhaust particulates is required and the key to achieving this is by the control of sulphur dioxide oxidation. Some compromise in gas phase hydrocarbon activity may be required to obtain the necessary reduction in the formation of sulphuric acid. New platinum- based catalysts have been developed to lower sulphur dioxide oxidation while at the same time minimising fouling of the catalyst due to carbonaceous soot. Thus particulate reduction is achieved primarily by efficient catalytic removal of the soluble organic fraction of the particulate.

Acknowledgment

evaluating the developmental diesel catalysts. Thanks are due to Ricardo International for

- 100-

k - 80-

Fig. 8 As predicted by the synthetic gas test, at l o w temperatures the conversion enicieney of the new platinuni- based formulations for hydrocarbons was somewhat less than that of the standard

I oxidation catalyst g

0

,= 250 m 3% 4 0 0 450 500 550 INLET TEMPERATURE,'C


References

1 M. P. Walsh, Platinum Metals Rev. , 1989,33, (4),

2 M. L. Church, B. J. Cooper and P. J. Wilton,

3 G. J. K. Acres and B. J. Cooper, Platinum Metals

4 R. A. Searles, Plalinum Metals Rev., 1985, 29,

5 R. A. Searles, Platinum Metals Rev., 1988, 32,

6 G. J. K. Acres, Platinum Metals Rev . , 1970, 14,

7 E. J. Sercombe, Platinum Metals Rev. , 1975, 19,

8 B. E. Enga, Platinum Metals Rev . , 1982,26, (2), 50 9 G. E. Hundleby, S.A.E. Paper No. 892134, 1989

10 P. Zelenka and W. Kriegler, S. A.E. Paper No.

11 D. J. Ball and R. G. Stack, S.A.E. Paper No.

194

S.A.E. Paper No. 890815, 1989

Rev. , 1972, 16, (3), 74

(4)9 163

(3), 123

(3), 78

(I), 2

900602, 1990

902110, 1990

12 A. F. Diwell and B. Harrison, Platinum Metals Rev . , 1981, 25, (4), 112

13 B. J. Cooper, Platinurn Metals Rev. , 1983,27, (4), 146

14 K. C. Taylor, in “Catalysis”, ed. J. R. Anderson and M. Boudart, Springer-Verlag, Berlin, 1984,

15 B. J. Cooper and T. J. Truex, S.A.E. Paper No.

16 J. T. Kummer, 3. Phys. Chem., 1986, 90, 4747 17 B. J. Cooper and J. E. Thoss, S.A.E. Paper No.

890404, 1989 18 R. D. CuthbertsonandP. R. Shore, S.A.E. Paper

No. 870626, 1987 19 R. D. Cuthbertson and P. R. Shore, 3.

Chromatogr. Sci., 1988, 26, 106 20 G. C. Bashford-Rogers and D. E. Webster, Proc.

Internat. Seminar “World Engine Emission Stan- dards and How to Meet Them”, Inst. Mech. Eng., London, 1991

5, p. 120

850128, 1985

Royal Commission Report on Diesel Emissions The impact of diesel emissions on the en-

vironment and methods for their control have been studied by the Royal Commission on En- vironmental Pollution, of the United Kingdom. On 4th September 1991, they published their report entitled “Emissions from Heavy Duty Diesel Vehicles”. The main recommendations to and conclusions for H.M. Government are:

Diesel vehicles are major contributors of atmospheric nitrogen oxides, which have adverse health effects and cause ozone formation, and of particulates which are probably carcinogens and which cause major soiling of buildings.

The Commission recommends that further reductions in both nitrogen oxides and particulates should be sought before the end of the decade. They also recommend that the Euro- pean Community’s steady state test cycle, during which emissions are measured against the standards set, should be made more demanding and along the lines of the U.S. Government’s transient test cycle, and that financial incentives should be created to encourage the use of engines with lower emission levels and to speed the replacement of vehicles and engines with new, less polluting ones.

The report also recommends that, as a matter of urgency, H.M. Government should start trials of “traps” or flow-through catalysts to catch particulates, providing grants for retrofit- ting them to buses, if the trials are successful. Emissions should be lower in urban areas so tighter limits should be set for vehicles

operating in these areas, such as buses. The report suggests that this would require the fitting of particulate traps and flow-through catalysts. [These would probably be based on platinum group metals].

Incentives should be created to subsidise the costs of an early introduction and the use of low sulphur fuel (0.05 per cent), and Government should encourage bus operators to use alternative fuels such as petrol, liquified petroleum gas, compressed natural gas or electricity.

Usefully, the report encourages Government to study the implications of the production and use of such fuels upon emissions of carbon dioxide and other pollutants, balancing the widespread view that carbon dioxide emissions are the only gas from motor vehicles that have implications for global warming. The report recommends that the use of metallic fuel additives should be banned until the exhaust products have been checked with toxicological testing. If a trap or catalyst is fitted, it is the exhaust leaving the device which should be tested.

The report provides further encouragement to H.M. Government to support tougher emissions legislation for diesel engines. In Europe an increasing number of carmakers are offering diesel vehicles equipped with platinum group metal catalysts, which result in substantially cleaner emissions than the 1992 European regulations stipulate for carbon monoxide and hydrocarbons. R.A.S.


Chemical Reaction Fronts on Platinum Surfaces By M. Mundschau and B. Rausenberger Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin

In many chemical reactions catalysed on platinum surfaces it is necessary that two reactants be adsorbed simultaneously. Often one reactant is so strongly adsorbed that it blocks the adsorption of the second; such a reaction is said to be self-poisoned. An example is the oxidation of carbon monoxide, where carbon monoxide forms a strongly adsorbed monolayer which effectively blocks the adsorption and decomposition of oxygen. Photoelectron microscopy shows, however, that oxygen can penetrate the carbon monoxide f i lm at special defect sites, typically inclusions or microdust particles, on the platinum. From these special adsorption sites the oxygen rapidly reacts with neighbouring adsorbed carbon monoxide. Reaction fronts initiate at these sites and rapidly propagate across the surface. A second type of self-poisoning occurs in decomposition reactions for which vacant sugace sites are necessary; for instance, the decomposition of nitric oxide in the presence of hydrogen. A monolayerfilm of nitric oxide poisons the reaction not by blocking the adsorption of hydrogen, but rather by preventing the dissociation of nitric oxide which requires a neighbouring unoccupied surface site. Empty sites are provided on impurity particles which weakly adsorb nitric oxide and initiate reaction fronts. lmpurity sites also initiate reaction fronts when graphite is removed from platinum by oxidation. In order to avoid self-poisoning in catalytic reactions, these studies suggest that special adsorption sites should be introduced artificially to provide vacant sites by adsorbing only weakly the reactants causing self-poisoning.

A chemical reaction front forms a boundary between unreacted material and an area which has undergone chemical reaction. A flame mov- ing through a combustible medium is an example of a chemical reaction front. In unmixed systems reactants must diffuse together. They react in what are called reaction-diffusion fronts (1).

If the reaction at the front involves a chain- reaction or autocatalytic step, in which formation of product accelerates the reaction, the front may travel many orders of magnitude faster than diffusion alone would permit (1). Fronts occur in a very large variety of chemical reactions, and are extensively studied in the relatively new science of synergetics, which

considers dynamic systems which are far from equilibrium (2).

Chemical reaction fronts also occur in monolayer films adsorbed on platinum during many catalytic reactions. The possibility of reaction fronts on platinum and the need for vacant surface sites was considered by Langmuir in 1921 (3). Fronts were detected by many indirect means (4), but can now be observed directly on platinum single-crystal or polycrystalline surfaces using photoelectron microscopy (5).

Photoelectron Microscopy In the photoelectron process, electrons are

emitted from a sample exposed to light. For solids, the energy of the light must exceed the


energy necessary to eject an electron into the vacuum. This minimum energy is called the work function. For most surfaces, this requires ultra violet light. Photoelectron emission is sensitive to a single adsorbed monolayer on a surface. Because of this it is possible to observe single monolayer films by photoelectron microscopy.

Images of surfaces are obtained by simply focusing photoelectrons onto a viewing screen. This is accomplished by using an electron lens similar to those used in conventional electron microscopy. Figure 1 is a schematic diagram showing the basic features of a simple photoelectron microscope with an electromagnetic lens. In practice, however, more complicated arrangements with multiple lenses are used (6,7). The contrast in a photoelectron image depends upon the relative photoelectron yield. Areas with different work functions release different numbers of photoelectrons, which, in turn, produce a different intensity on a viewing screen.

Although atomic resolution has not been achieved in photoelectron microscopy, the great advantage of this technique is its ability to observe dynamic events in real time, such as reaction fronts ( 5 ) and chemical kinetic oscillations (8-10) in single monolayer adsorbed films. These can be recorded at ordinary video rates (0.04 s per frame) or photographed directly from the viewing screen. Still photographs, however, only poorly portray the dynamics occurring during catalytic reactions on surfaces. The studies reported here were performed on single crystal platinum surfaces under ultra high vacuum.

The Oxidation of Carbon Monoxide on Pt(100)

Under certain reaction conditions, fronts are seen during the catalytic oxidation of carbon monoxide on platinum. The conditions necessary are shown schematically in Figure 2. This reaction is self-poisoned by carbon monoxide. At lower temperatures and high partial pressure of carbon monoxide, the carbon monoxide effectively forms an impenetrable

Vacuum chamber I rn age i nten sit i e r

Viewing screen I I

1

4 -20kV

I I \ I I

Light source Electromagnetic lens Sample \

Fig. 1 This simplified version of a photoelectron microscope shows the arrangement whereby photoelectrons releas- ed from a sample exposed to light are focused onto an image intensifier by an eleetromagnetic lens

monolayer fdm on platinum which blocks the adsorption and dissociation of oxygen, and stops the reaction. This is represented in Figure 2(a). In order for the reaction to proceed, a hole must be formed in the carbon monoxide film to allow the adsorption of oxygen. One way to produce holes in the film is to increase the temperature to 500 K and thermally desorb some of the carbon monoxide Figure 2(b). On an ideal defect-free surface this would occur randomly throughout the film and no fronts would be formed. A second method to produce holes in the carbon monoxide film is to provide impurity sites on the platinum which do not adsorb carbon monoxide, but which adsorb oxygen.

Oxygen adsorbed on such sites can react with the side of the carbon monoxide film, which is vulnerable to attack, although the top of the film remains inert. This is shown schematically in Figure 2(c) and (d). Once initiated at an impurity site, the reaction front propagates out into the carbon monoxide film, removing it by forming carbon dioxide, which


0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 c c c c c c c c c c c c c c c

3 5 0 K ! 1

0 0 0 0 0 0 0 0 0 c c o o c c c c o o c c

W O K I I

0 0 0 0 0 0 0 o o o o o o o 9 c c c c c c c c c c c c c

IrnpLri ty 3 5 0 K I - - 1

0 - - 0 0 0 0 0 0 0 c c c c o o o o 0 0 0 0 c c c

3 5 0 K t - - I

Fig. 2 The origins of reaction fronts in the carbon monoxide-oxygen reaction are shown. (a) At 350 K and high carbon monoxide pressure the reaction is self- poisoned by a monolayer film of carbon monoxide which blocks the adsorption of oxygen. (a) At 500 K some carbon monoxide desorbs allowing oxygen to adsorb. No fronts form because oxygen adsorbs uniformly on many sites. (c) An impurity with low &ty for carbon monoxide forms a hole in the carbon monoxide film and allows oxygen to adsorb. (d) The front migrates out from the impurity site as oxygen reacts with the side of the carbon monoxide film

desorbs, and replacing it by adsorbed oxygen. An adsorbed monolayer of oxygen does not poison the reaction. By artificially adding such impurity sites on the platinum, the reaction can be made to proceed more efficiently at lower temperatures, or at higher partial pressures of carbon monoxide. In practice, such sites are often present in the form of impurity inclusions or dust particles.

A reaction front propagating through a monolayer of carbon monoxide adsorbed on


Pt{lOO} at 350 K is shown as a photoelectron image in Figure 3. The front initiated at an impurity inclusion, seen in the centre of each frame. The monolayer film of oxygen, which forms behind the reaction front, appears dark relative to the carbon monoxide because it has a higher work function, 6.46 eV (ll) , compared to 6.11 eV of carbon monoxide (11). A deuterium lamp, which has a maximum photon energy of -6.9 eV (180 nm), was used as the light source.

To initiate the front, oxygen at a pressure of l.OxlO-* Pa was added to the vacuum chamber of the microscope. This is near to the maximum pressure at which observations can be made. The partial pressure of carbon monoxide was increased until the platinum surface was saturated with a monolayer of carbon monoxide. This required a partial pressure of carbon monoxide of only 2 . 4 ~ Pa. Im- purity sites were also saturated with adsorbed carbon monoxide under these conditions, and the reaction was self-poisoned. When the partial pressure of carbon monoxide was lowered reaction fronts initiated at dust particles and inclusions.

The carbon monoxide, which is relatively weakly adsorbed on some impurities, is displaced by competitive adsorption of oxygen. Ox- ygen adsorbed on the impurity sites then reacts with the side of the neighbouring carbon monoxide film.

The reaction-diffusion fronts illustrated in Figure 3 show an anisotropy. This is caused by step bunches on the surface which hinder diffusion. Step bunches, which are groups of atomic steps, are often observed on platinum surfaces after sputtering (12), thermal etching or catalytic etching (13). They also arise from glide lamellae or slip bands (14) which form on platinum when it is thermally stressed. Figure 4 shows step bunches on a Pt{ loo} single crystal surface. To make them visible in the photoelectron image, they were decorated with carbon (15). This was removed before the catalytic reaction, by heating in oxygen. The directions of the step bunches varied in different areas of the crystal.

190

with low sanity

Fig. 3 A reaction front during the oxidation of a monolayer of carbon monoxide a lorbed on Pt{ 100) is shown at 0, 15, 18 and 25s. Bright areas on the photoelectron image are monolayers of carbon monoxide, dark areas are monolayers of oxygen. The impurity inclueion initiates a front at 350 K. Diameter: 230 pm

The reaction-diffusion fronts travel more slowly over the steps compared to travel along them. Surface steps can strongly bind reactants and form activation barriers for diffusion over them (16, 17). Diffhsion over steps is impeded and therefore reaction-diffusion fronts travel with a lower velocity in directions over steps, relative to directions parallel to steps.

The Nitric Oxide +Hydrogen Reaction on Pt(100)

In excess hydrogen, platinum readily catalyses the formation of ammonia from NO (18). This is an unwanted side reaction in automobile air pollution control catalysts, on which nitric oxide in the presence of hydrogen is preferentially converted into nitrogen and water (18). In fact, according to Shelef the unwanted production of ammonia was one of the most difficult problems to overcome in the

Fig. 4 The step structure on Pt{ lOO} is shown. Reaction-diffusion fronts migrate more rapidly along steps than over them, because of ditrusion barriers at the steps. Steps are decorated with carbon. Diameter: 230 pm


Fig. 5 A front initiated at a duet particle in the reaction between nitric oxide and hydrogen on Pt{ 100) is shown at 0 ,5 , 10 and 12 a. The dark areas are monolayer nitric oxide, and the bright areas are ammonia. Temperature=415 K. Diameter: 230 Frn

development of automotive catalytic con- production of ammonia was also detected in the verters, and rhodium was eventually gas phase by mass spectroscopy, in agreement substituted for some of the platinum (18).

Reaction-diffusion fronts are seen in the reaction between nitric oxide and hydrogen on Pt{lOO} under certain reaction conditions, see Figures 5-7. The dark areas in these are covered with a single monolayer of nitric oxide, work function 5.82 eV (19). The bright areas are believed to be ammonia or a precursor of ammonia (that is NH or NH,) based upon its work function (5 eV). This work function rules out the bright areas being pure hydrogen. The

with studies by Madden and Imbihl (20).

Fig. 6 The anirotropy of fronts is shown during the reaction between nitric oxide and hydrogen at 375 K. Fron~a migrate faater along steps. Diameter: 230 pm

Platinum Metals Rev,, 1991, 35, (4) 192

Fig. 7 The collision of fronts during the reaction between nitric oxide and hydrogen at 380 K is rhown. Diameter: 230 pm

The fronts of Figure 5 were initiated as follows: The sample was kept at 415 K and the hydrogen pressure adjusted to 1 . 7 ~ 1 0 - ~ Pa. The surface was then saturated with nitric oxide by increasing its partial pressure to 1 x10d2 Pa. Upon reducing the partial pressure of nitric oxide to lxlO-' Pa, the fronts initiated at dust particles after an induction time of a few seconds. The fronts pro- pagated out into the nitric oxide monolayer at a speed of 9 &s in directions along steps and about one third as fast across steps.

Anisotropy of the fronts is more pronounced at lower temperatures. Figure 6 shows a front initiated at a dust particle at 410 K and then cooled to 375 K. The long streamers follow step bunches. Anisotropy increased at lower temperatures because diffusion over the steps becomes more difficult.

The collision of two fronts is shown in Figure 7; each initiated at a dust particle at 410 K. The sample was cooled to 380 K to reduce the speed of the fronts and to allow sti l l photography. The impurity particles apparently initiate the


reaction by providing empty sites which are necessary for nitric oxide to decompose.

Oxidation of Graphite on Pt{ 100) Graphite and other carbonaceous materials

are troublesome contaminants which block catalytic reactions on platinum. Often carbon must be removed periodically from platinum surfaces by combustion with oxygen. The reaction fronts formed during the oxidation of graphite on Pt{ 100) are shown in Figure 8. The light areas are covered with carbon, while the dark areas are covered with oxygen and show where the graphite was removed. The surface of graphite, which typically grows with its close-packed basal plane parallel to the platinum surface, can be quite inert towards oxygen and oxygen has difficulty in penetrating the graphite film. The graphite film was not a single monolayer, and can grow to become quite thick. Oxygen penetrates the film at dust particles and reacts with the side of the film. Once a hole is formed in the film, the graphite is rapidly removed as the reaction fronts propagate away from the initiation sites. The holes

Fig. 8 Reaction fronts are shown during the oxidation of graphite on Pt{100}. Dark areas are c o v e d with adsorbed oxygen and show where graphite was removed. Fronts initiate at impurity particles. Diameter: 230 pm

in the graphite film are circular. Lack of anisotropy occurs because graphite does not diffuse. These studies suggest that graphite may be more efficiently removed from platinum surfaces if particles, which readily adsorb oxygen, are intentionally added to the surface.

Conclusions Many catalytic reactions on platinum are

limited by the availability of unoccupied surface sites. A key to the production of more efficient catalysts, for reactions which exhibit self-poisoning, appears to lie in the introduction of empty surface sites through the addition of impurities which only weakly adsorb the reactants that cause self-poisoning. Inert films which normally cause self-poisoning are removed by reaction fronts which initiate at holes in the film at impurity sites.

Acknowledgements These studies were done under the direction of

A. M. Bradshaw and in collaboration with E. Zeitler and W. Engel of the Electron Microscopy Division of the Fritz-Haber-Institut, Berlin. We thank M. E. Kordesch for work in the construction of the instrument, based upon a design of E. Bauer.


References 1 P. Gray and S. K. Scott, “Chemical Oscillations 10 G. Ertl. Catal. Lett., 1991, 9, 219

and Instabilities”, Clarendon Press, Oxford, 1990 11 H. H. Rotermund, S. Jakubith, A. von Oertzen, 2 V. A. Vasilev, Yu. M. Romanovskii, D. S. S. KubalaandG. Ertl.,J. Chem. Phys., 1989,91,

Chernavskii and V. G. Yakhno, “Autowave 4942 Processes in fietic System”, VEB Deutscher 12 E. Savitsky, V. polyako~, N. Grin8 and N. Verlag der Wissenschaften, Berlin, 1987 Roshan, “Physical Metallurgy of Platinum

3 I. Langmuir, Trans. Faraday soc., 1921, 17, 607 Metals”, Mir Publishers, Moscow, 1978, p.106 4 R. Imbihl, in: ‘‘Optimal Structures in 13 M. Flytzani-Stephanopoulos and L. D. Schmidt,

Heterogeneous Reaction Systems”, ed. P. Plath, pmg. Surf. Sci., 1979, 9, 83 14 A. H. Cottrell, “Dislocations and Plastic Flow in Springer Series in Synergetics, 1989, p.26

5 M. MundSchaW M. E. brdesch, €3. Crystals”, Clarendon Press, Oxford, 1953, p.3 Rausenberger3 w’ Engel, A‘ M’ and E‘ 15 M. E. Kordesch, W. Engel, G. John Lapeyre, E.

Zeitler and A. M. Bradshaw, Appl. Phys. A., Zeitler, Surf. Sci., 1990, 227, 246 6 0. H. Griffith and G. F. Rempfer, in “Advances 1989, 49, 399

in Optical and Electron Microscopy”, Vol. 10, eds. R. Barer and V. E. Cosslett, Academic Press, London, 1987 p.269

7 E. Bauer, M. Mundschau, W Swiech and W. Telieps, Ultmmicroscopy, 1989, 31, 49

8 H. H. Rotermund, W. Engel, M. E. Kordesch and G. Ertl, Nature (Lrmdon), 1990, 343, 355

9 S. Jakubith, H. H. Rotermund, W. Engel, A. von OertzenandG.Ertl,Phys.Rev. Lea., 1990,65,3013

l6 M. J. cardilloy Lanmuir9 1985* 13 17 J. A. Serri, M. J. Cardillo and G. E. Becker, 3.

18 M. Shelef, Catal. Rev. Sci. Eng. 1975, 11, 1 19 T. Fink, J. -P. Dath, M. R. Bassett, R. Imbihl

20 H. H. Madden and R. Imbihl, Appl. Surf. Sci.,

phys.7 19829 77, 2175

and G. E d , Surf. Sci., 1991, 245, 96

1991, 48/49, 130

Platinum Catalyses the Conversion of Methane to Higher Alkanes

A research group at the Universite de Nancy and Laboratoire Maurice Letort, France, has found that the standard platinum catalyst EUROPT-1 promotes the conversion of methane to a range of saturated hydrocarbons up to C, or C,.

A recent report (M. Belgued, P. Pareja, A. Amariglio, and H. Amariglio, Nature, 1991, 352, (6338), 789-790) indicates that the reactions take place at moderate temperatures. The catalyst was reduced in a flow of hydrogen at 400°C, followed by a helium flush and cooling to the temperature of the experiment (150 to 28OOC). The sample was then fed with a flow of pure methane. Transient evolutions of hydrogen and ethane were immediately observed. At 250OC and after an exposure to methane of 1 minute, the rate of ethane evolution passed through a maximum. Fast production of saturated hydrocarbons ranging from C, to C, or C, resulted from subsequently flushing the catalyst with hydrogen at the same temperature.

It was concluded from the results of a temperature-programmed desorption experiment carried out under the same conditions that the fraction of methane converted was 19.3 per cent. The authors have experimental evidence to support their hypothesis that the

higher hydrocarbons are obtained via oligomerisation of CH, species. They indicate two potential advantages of their method over the oxidative coupling for the conversion of methane into higher hydrocarbons: these being the much lower reaction temperatures and the fact that unconverted methane can be recycled. Low conversion efficiency is at present a limita- tion of this new process, however, and the possible inhibiting effects of deposited carbon on catalyst efficiency are currently being assessed. The technological progress implied by these results indicates that the use of a platinum catalyst, together with the choice of reaction temperatures and use of a flow reactor may

Metal-Hydrogen Systems A previous issue of this journal carried a

selective report of the International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications, held in Banff, Canada, September 2nd-7th7 1990, (R.-A. McN., Platinum Metals Rev., 1991, 35, (l), 24-27). The papers presented at that meeting, including those in the special sessions on hydrogen pairing in metals, have now been published in the Journal of the Less-Common Metals, 1991, 172-174, Parts A and B.

have been significant factors. D.T.T.


Bradshaw

16 M. 1. Cardillo. Lanmuir. 1985. 1. 4 17 J. A. Serri, M. J. Cardillo and G. E. Becker, 3.

Chem. Phys., 1982, 77, 2175

The Plastic Flow of Iridium By P. Panfilov, A. Yermakov, V. Dmitriev and N. Timofeev Laboratory of Strength, Ural State University, Sverdlovsk, U.S.S.R.

The use of iridium as a crucible material has necessitated the development of technology for refining the metal to a high level of purity, and also the establishment of optimum conditions for fabricating the metal into finished products. The latter is of great importance insomuch as iridium cleaves under tension at room temperature but under compression it is deformed in a plastic manner. Manufacturers of iridium products have assumed that its poor malleability is due to the influence of impurities which are very difficult to remove under industrial conditions. Ultra high purity iridium, however, can be forged in much the same way as platinum (1).

At the present time the nature of the brittleness of iridium continues to be a puzzle (2). On the one hand, the cleavage which occurs in iridium is usually considered to be an inherent property, and the influence of impurities only a secondary factor (3). On the other hand, an alternative view of the problem exists in the literature (4); that is, the brittleness is considered to be due to some impurities which embrittle this plastic face-centredcubic (f.c.c.) metal. For example, if iridium contains more than 10 ppm of carbon then it cracks when rolled; carbon-free iridium however, can be forged without cracking (2). Analysis of the deformation occurring in iridium single crystals (5, 6) and the observation of deformation tracks near cleavage cracks on crystal surfaces (S), have shown that the crystals were deformed by octahedral slip, as is usual for f.c.c. metals. The presence of both deformation and annealing twins in pure iridium and in iridium-0.3 per cent tungsten, however, may be considered as the result of an alternative mechanism, namely plastic flow (4, 8,9). In this paper the relation- ships between the plastic deformation of iridium, its brittleness, the role of impurities in its mechanical behaviour, and the optimum

regimes for processing iridium workpieces will all be discussed.

The process of manufacturing high purity plastic iridium and its alloys involves a combination of both oxidation-induction melting and electron beam melting. Such a procedure enables materials which are free of non-metallic and gaseous impurities to be obtained. Growing single crystals by electron beam zone melting is the final stage of purification. Large single crystal, or quasi single crystal, work pieces 100 to 150 mm in length and with diameters of 30 to 55 mm are usually produced. An example is shown in Figure 1. Orientated specimens have been cut from large industrial crystals of pure iridium, Oak Ridge alloy iridium-0.3 per cent tungsten, and OZM alloy iridium-3 per cent rhenium-2 per cent ruthenium by spark erosion techniques. Specimens of single crystals, 3 x 2 x 2 mm in size, have been compressed along <loo>, <110> and <111> directions, at room temperature. Also, iridium wires have been prepared from single crystal pieces for tensile testing at high temperatures under vacuum.

Experimental Results The plastic deformation of our iridium single

crystals has been described previously (10). Under tensile conditions, strongly orientated anisotropy of both the yield strength and the hardening characteristics during deformation takes place along the “soft” <110> and “hard” <loo> crystallographic directions. However, in the case of compression, anisotropy is absent. The deformation mechanism in iridium was investigated by metallographic and transmission electron microscopy, which confirmed the conclusion that iridium deformation occurs by octahedral slip of perfect dislocations having <110> Burgers vector.

A study of single crystal foils by transmission


Fig. 1 Electron beam zone melting is used during the final stage of purification of iridium single crystals. The cryslals may have diameters of 30 to 55 mm and lengths of 100 to 150 mm

electron microscopy has shown that two types of dislocation structure may be distinguished. Single dislocations, dipoles and dislocation balls are usually observed only near to the edges of very thin foils (Figure 2a) and in thick, almost opaque, areas of foil containing high density dislocation nets (Figure 2b). No deformation, annealing and growth twins were observed in uncracked areas of the single

Fig. 2 The dislocation features observed on iridium thin foils: single dislocations, dipoles and dislocation balls only occur close to the edge of very thin foils (a), while high density dislocation nets occur in thicker parts (b)

crystal foils studied. Qualitatively, dislocation stuctures in iridium crystals were similar to those normally present in f.c.c. metals, but the density of the dislocations in the iridium was so high that it could only be compared with the density of dislocations in irradiated metals. As has been reported previously (3), the

fracture mode of iridium was not influenced by small concentrations of tungsten in the matrix. Compression tests on iridium alloys have shown that hardening impurities such as tungsten, rhenium and ruthenium result in an increase in yield strength and in hardening during deformation, by comparison with pure iridium, as is shown in Figure 3. The yield strength of the alloys is about 200 MPa, twice that of pure iridium. Metallic impurities do not embrittle iridium; and iridium and its alloys do not fail under compression at room temperature. Our iridium contained more metallic impurities than iridium provided by Johnson Matthey (l), however, in both cases the iridium was plastic and deformed satisfac- torily. In contrast, even low concentrations of carbon resulted in the embrittlement of iridium crystals under the effects of compression at room temperature.

The plasticity of polycrystalline wires when tensile tested was found to depend on both the temperature at which the test was carried out and the diameter of the wire, as illustrated in Figure 4. Thus deformation prior to failure of thick wire (1.5 mm diameter) is increased from 3-5 per cent at room temperature to 25 per cent at 5OOOC. At higher temperatures the plasticity of wire of this thickness does not change.

Plaiinum Metals Rev., 1991, 35, (4) 197

3-0 60 DEFORMATION, per Cent

Fig. 3 The addition of alloying amounts of rhenium, ruthenium and tungsten to iridium increases the yield strength during compressive deformation of single crystals

Similar behaviour of iridum at elevated temperatures has been reported in the literature (1 1). In the present case the increase in deformation prior to failure at 50OOC can only be explained by the increasing dislocation mobility, as recrystallisation in iridium only commences at 1000°C. The plasticity of thin wire (0.3 mm diameter) is decreased from 10-15 per cent at room temperature to 3-5 per cent at 700OC; it then starts to increase to 15-20 per cent at a temperature of 1200°C, see Figure 4. These changes may be connected with the processes of recrystallisation. The increase of plasticity of iridium at these temperatures has been described elsewhere (8). The decreased deformation prior to failure in the temperature range 20 to 700°C cannot be regarded as an inherent feature of iridium insomuch as the phenomena which can cause this to happen are absent in pure f.c.c. metals. This means that the decrease in deformation is determined by external factors. The first of these is the influence of carbon which could have diffused into the iridium during the working of the metal into wire, when carbon is used as a lubricating material. Non- metallic impurities can enhance the dislocation mobility in metals and can therefore accelerate the processes of plastic flow, and lead to cleavage type fractures (7, 12). The second

external factor is the presence of a metal f i lm

which appears on the surface of the wire as a result of evaporation of the heating element while the test is carried out under vacuum. Consequently, this can embrittle the iridium and decrease the yield strength. A platinum film on iridium reduces its yield strength (13), a copper film has lowered the yield strength of iridium crystals, which were stretched along the <loo> direction, from 100 MPa to only 10-20 MPa.

The degree of roughness of crystal surfaces has an influence on their mechanical properties when they are stretched along the <110> direction. Thus, non-polished crystals with a rectangular cross section cleaved after 15 to 20 per cent deformation at room temperature. A large number of small cracks covered their surfaces. After electropolishing the elasticity of such crystals increased to 30 to 40 per cent. In this case the number of surface cracks on the crystals was significantly reduced, and as a rule these occurred at the edges of the crystal. Elec- tropolished crystals having elliptical sections cleaved after 60 per cent deformation; no surface cracks were observed on them. Crystals with a circular cross section were parted by cleavage after 80 per cent elongation (4).

k f-- 1.5mm diameter

400 800 1 2 0 0 TEMPERATURE I 'C

Fig. 4 Tensile testing of polycrystalline iridium w i r e s h a s shown the plasticity to depend on both the test temperature and the diameter of the apecimens


Similar behaviour has been noted for polycrystalline iridium; plane specimens failed without deformation when tensile tested at room temperature and circular wires cleaved after 10-20 per cent deformation.

Discussion It has been pointed out that iridium single

crystals were deformed at room temperature by octahedral slip of perfect dislocations with <110> Burgers vector, as is usual for f.c.c. metals, although some differences do exist between the different metals. Iridium has a very high yield strength compared with that of other pure f.c.c. metals. This may be connected with the low mobility of <110> dislocations. Addi- tionally iridium is significantly hardened during deformation, which may be explained by its ability to accumulate high dislocation densities. Mechanical twinning can be operative at room temperature, but its contribution to flow at such temperatures is insignificant, thus the high hardening of iridium cannot be determined by twinning (4, 6). Anomalous elastic moduli of iridium (14, 15) may be the cause of the differences between iridium and the more usual f.c.c. metals, on the atomic level. This cannot be considered, however, as the direct cause of the tendency of iridium to fracture in a brittle manner, because thin foils of iridium single crystal separate in a similar way to thin foils of plastic aluminium (10).

Of course, the inclination of iridium to cleave of its own accord, without some relationship to its other mechanical properties, looks puzzling. Factors such as the high rate of work hardening during deformation, the large deformation that takes place prior to failure, and the separation of crystals only under the influence of tensile stresses produced during drawing and rolling, permit a very simple hypothesis to be formulated about the brittleness of iridium. It may be supposed that the plasticity of the iridium crystal has been completely exhausted during previous stages of deformation. Indeed, a large dislocation density accumulates in the material at the final stage of flow, thus requiring high stresses for further deformation. Under such

conditions the stress concentrations at surface defects, such a notches, can reach the theoretical value needed to promote cleavage cracks. The deformation tracks near to cleavage cracks may be considered as visible indications of the changing stress conditions at these places. It appears to us' that these tracks must be seen as twin lamellae because they appear under the influence of high stresses, when the formation of mechanical twins will be more justified than octahedral slip. It is also known that mechanical twinning can accompany the growth of cleavage cracks in body- centred-cubic (b.c.c.) metals at low temperatures, and the fracture mechanism maps for both iridium and b.c.c. metals are similar (11). The latter may be considered as another factor in support of twinning near to cleavage cracks in indium. In addition, micro cracks in thin iridium foils produce partial dislocations, and as a result micro twin lamellae are formed nearby (10).

The choice between slip bands and twins is not important as they only accompany the growth of long cracks, and they are not the cause of brittle fracture. The failure mechanism for iridium crystals which has been proposed elsewhere (7) is unlikely to apply as the alternative slip is absent ahead of cleavage cracks in crystals which were stretched in the <110> direction, and deformation tracks are absent near to small cleavage cracks (10). In addition, the alternative slip mechanism ignores the large deformation that occurs prior to cleavage. The brittleness of iridium seems to be a consequence of the direct breaking of the atomic bonds at the tip of cracks. The similarity between the failure of iridium crystals and the fatigue fracture of aluminium has been reported (16); in both cases the materials were heavily deformed prior to failure.

Mechanical twinning which does not influence plastic flow in single crystals can contribute to the lower plasticity of iridium polycrystals. For example, brittle cracks can advance along twin lamellae in thin iridium-0.3 per cent tungsten foils. A transmission electron microscopy study of the morphology of iridium


films, which were evaporated in vacuum, has shown that the number of growth twins decreases with increasing crystallite sizes. This tendency results in the complete absence of twin lamellae in single crystal films (17). The analogous behaviour of twins in films of other materials has been observed, for example, in P- silicon carbide (18). Growth twins are dangerous features in foils as they can be the embryo for both deformation and annealing twins (19).

In conclusion, some recommendations can be formulated for the selection of the optimum conditions for processing iridium. The main condition is that the material must be kept free from non-metallic impurities during all stages of manufacture. Grain boundaries are danger points in work pieces, especially if the average grain size is of the order of some millimetres. Therefore it is desirable that single crystal or fine grained polycrystalline work pieces are used. The tensile stresses must be kept to a minimum level; in our case at the mechanical w o r k stage, the large crystals were first forged and after that they were subjected to rolling. The optimal temperature range for processing iridium work pieces is 500 to 9OOOC as the material is plastic at these temperatures, but recrystallisation does not take place. Also, the processing of iridium in this temperature range can be undertaken in air as intensive oxidation only takes place at 1000°C and above. Processing at temperatures lower than the recrystallisation temperature prevents formation of additional danger points in work pieces such as new grain boundaries and twins.

1

2 3

4

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9

10

11

12

13 14

15

References J. R. Handley, Platinum Metals Rev. , 1986, 30, (l), 12 I. E. Cottington, Personal communication, 1990 S. S. Hecker, D. L. Rohr and D. F. Stein, Metall. Trans., 1978, 9A, 481 C. A. Brookes, J. H. Greenwood and J. L. Routbort, 3. Appl. Phys., 1968,39,2391; 3. Inst. Met., 1970, 98, 27 P. Haasen, H. Hieber and B. L. Mordike, Z . Metallkd., 1965, 56, 832 C. N. Reid and J. L. Routbort, Metall. Trans., 1972, 3, 2257 S. P. Lynch, Muter. Forum, 1988, 11, 268; Acta Metall., 1988, 36, 2639 B. L. Mordike and C. A. Brookes, Platinum Metals Rev. , 1960, 4, (3), 94 D. L. Rohr, L. E. Murr and S. S. Hecker, Metall. Trans., 1979, lOA, 399 P. Panfilov, A. Yermakov, G. Baturin and A. Timofeev, Fiz. Metal. Metallovedenie, (in Russian), 1989, 67, 813; A. Yermakov, P. Panfiiov and R. Adamesku, 3. Muter. Sci. Lett., 1990, 9, 696; P. Panfdov, A. Yermakov and G. Baturin, ibid., 1990, 9, 1162 C. Gandhi and M. F. Ashby, Scripta Metall., 1979, 13, 353; Acta Metall., 1979, 27, 1565 I. M. Robertson and H. K. Birnbaum, Acta Metall., 1986, 34, 353 G. Reinacher, Z. Metallkd., 1967, 58, 831 R. E. MacFarlane, J. A. Rayne and C. K. Jones, Phys. Lett., 1966, 20, 234 R. Adamesku, V. Barkhatov and A. Yermakov, Vysokochistie Veschesrva, (in Russian), 1990, (3), 219

16 G. G. Garrett and J. F. Knott, Acta Metall., 1975, 23, 841

17 A. S. Solov’iov, Communication on XI11 Conference, “Recitation, Physical Properties and Applications of High Purity and Single Crystal Refractory and Rare Metals”, October 1990, Suzdal, U.S.S.R.

18 K. Koumoto, S. Takeda, C. H. Pai, T. Sat0 and H. Yanagida, 3. Am. Ceram. Soc., 1989,72, 1985

19 J. W. Matthews, Acta Metall., 1970, 18, 174

Ammonia Sensor Uses Platinum Films There is a need to measure ammonia gas con-

centrations under clinical and industrial conditions, and for environmental protection.

Now researchers at the C.S.I.C., Spain, have developed a new ammonia gas sensor device based on Schottky platindn-gallium arsenide barrier diodes with discontinuous platinum fdms which have excellent sensitivity between room temperature and 150°C (L. M. Lxhuga, A. M e , D. Golmayo and F. Briones, J. AppZ. P~YS. , 1991, 70, (6), 3348-3354).

The devices have a dual metallic confgura- tion consisting of a thick deposited platinum circular dot and a thin porous platinum film evaporated over and outside the contact dot. Gas-induced modification in Schottky diode electrical properties are monitored by measuring changes in the diode capacitance as a function of time.

In synthetic air it was possible to measure ammonia concentrations above 150 ppm with response times lower than one minute.


Partners in Innovation Conference AIMING TO CATALYSE SUCCESSFUL COMMERCIAL PRODUCTS

On Thursday 18th July, 1991, some two hundred leading academics, in- dustrialists, senior civil servants and the government minister with responsibility for higher education and science attend- ed a conference hosted by His Royal Highness the Prince of Wales at his home, Highgrove House, in Gloucester- shire. Organised under the auspices of The Prince of Wales Award for Innova- tion, and jointly sponsored by Johnson Matthey and McKinsey and Company, the purpose of the conference, entitled “Partners in Innovation”, was to develop an effective programme to aid wealth-creating innovation by the sharing of practical ideas and successful experience.

In his introductory address, David Davies, Chairman of Johnson Matthey, spoke of the collaboration with universities and research institutes which has been an important element of Johnson Matthey’s research and development strategy for many years. Often, such collaboration had resulted from the interest stimulated by the long-established platinum metals loans scheme [see Platinum Metals Rev., 1987, 31, (4), 171-1721. Mr Davies gave a number of examples of commercial products developed with university help, first highlighting the platinum-based drug carboplatin, the discovery of which resulted from the secondment of a Johnson Matthey scientist to Michigan State University, where the initial research was carried out. This work is continuing, in association with The In- stitute of Cancer Research and The Royal Marsden Hospital.

The innovative approach that Johnson Matthey took during the development of the rhodium-platinum catalysts, which are now widely used for the control of automobile exhaust emissions, was based upon original research at U.K. universities. Connections with these establishments have been maintained

over many years, and Johnson Matthey have recently set up a consortium to co- ordinate academic and in-house research on autocatalysts, and are also providing funds to support such work at selected universities.

It is interesting to recall that as long ago as the 1930s when Dr. Francis Bacon was carrying out his pioneering work at King’s College, London, and at Cam- bridge University on the development of fuel cells as a practical means of generating electricity, he was supplied with activated platinum gauzes by Johnson Matthey. The primitive cell he assembled was the forerunner of the highly sophisticated generators that later provided in-flight electric power for the Apollo lunar and U.S. space shuttles. The success of these units in space resulted in further on-going development which may now lead to the production of commercially viable fuel cells for a wide variety of terrestrial applications.

In his address the Prince of Wales told his audience that he was moved to launch this initiative on innovation because too many of the winners of the innovation award scheme, which he had set up in 1981, failed to achieve commercial success, and he invited his guests to find solutions to the problems that were preventing new ideas, discoveries and in- ventions being turned into commercial products. In Britain, he said, instances of cooperation were too few; but the Prince cited as a good example of the type of cooperation he would like to encourage, the project involving Johnson Matthey, Rolls-Royce, the Government’s Trade and Industry Department and a yet to be selected higher education institute, which intends to produce a fuel cell based on platinum.

By his action the Prince of Wales a ims to catalyse the educationalists, the in- dustrialists and the relevant government departments to work together for the benefit of all.

Platinum Metals Rev., 1991, 35, (4), 201 201

Recovery of Platinum Group Metals from High Level Radioactive Waste POSSIBILITIES OF SEPARATION AND USE RE-EVALUATED

By R. P. Bush AEA Technology, Harwell Laboratory, Oxfordshire, England

When nuclear fuel is irradiated in a power reactor a wide range of chemical elements is created by the fission of uranium and plutonium. These fission products include palladium, rhodium and ruthenium, and could in principle constitute a valuable source of these three metals. Their separation from the fuel during reprocessing operations is, however, a complex matter. Various processes have been proposed and evaluated, mainly on a laboratory scale. To date none of them has been established as applicable on a commercial scale, but investigations with this aim are continuing in several countries. Even a complete separation of the platinum group metals from other nuclides would yield a radioactive product, because of the presence of active isotopes of the platinum group metals. These would be expected to restrict the practical utilisation of platinum group metals created by nuclear jisswn, unless an isotope separation technique can be developed, or the metals are stored until the radioactivity has decayed.

The irradiation of nuclear fuels in power reactors leads to the production of atoms of a wide range of fission products, ranging in atomic mass from 70 to 160. These fission products generally constitute components of the radioactive waste generated by the nuclear fuel cycle. They include three of the platinum group metals, namely palladium, rhodium and ruthenium, which are valuable because of their scarcity and their strategic importance.

It is the purpose of this paper to review the quantities of the platinum group elements produced (frequently termed the arisings) during nuclear power generation, to describe their behaviour within the fuel cycle, and to consider the feasibility of separating them from suitable waste streams and utilising them industrially.

The question of whether these metals might be separated from nuclear wastes was considered in the early days of the nuclear industry, and interest in it has re-emerged at intervals since then. The topic was previously

reviewed in Platinum Metals Review in 1970 (1). The current revival of interest has resulted partly because of the increasing economic importance of rhodium. This metal is a crucial component of the three-way catalysts used for automobile emission control, and the demand for it is therefore strong. However, rhodium is mined in conjunction with platinum and its supply is therefore linked to that of platinum. Increases in the price of rhodium over the last few years have led to renewed interest in possible new sources. For this reason, the present paper concentrates on recent technological developments that might have a bearing on the separation of rhodium from nuclear waste.

Production of Platinum Metals in Nuclear Fuel

Palladium, rhodium and ruthenium are produced in irradiated fuel at fission yields of a few per cent. The quantities produced depend on the type of reactor system and on the burn-up


Isotope

Ruthenium 99 100 101 102 103 104 106

Rhodium 102 102m 103 1 061b'

Palladium 104 105 106 107 108 110

Table I

Composition of Fission Product Platinum Group Metals after Cooling for Five Years

Content, weight

per cent

trace

4.2 34.1 34.0 trace 23.9 3.8

trace trace 100

trace

16.9 29.3 21.3 17.0 11.7 3.8

Half-life

stable

stable stable stable 39 days stable 368 days

2.9 years 207 days stable 30 seconds

stable stable stable 6.5 x lo5 years

stable stable

Specificla' activity,

Ci/g metal

Low

8

1.3 x 10-3 3 x 10-5

la1 1 Curie ICi) 3.7 x 1 O ' O Becquerel Ib) '04Rh exists in secular equilibrium with 'O'Ru. and decays rapidly to "'OPd

to which the fuel is taken, that is the thermal energy generated by fission by unit mass of fuel. In a commercial light water reactor at a burn-up of 33GWdhe about 4 kg of platinum group metals are produced per tonne of heavy metal in the fuel. In a fast breeder reactor, because of the higher burn-up (about 100GWdlte) and the different neutron spectrum, about 19 kg of platinum group metals per tonne are produced. For light water reactor fuel, the approximate composition of the platinum group metals fraction is: palladium 33, rhodium 11 and ruthenium 56 per cent.

5 x 10-6

Decay mode

PY

Low energy P

y, electron capture by, electron capture

PY

Low energy p

Rhodium, currently the most valuable of the three, is generated in the lowest yield.

The isotopic composition of the fission derived platinum group metals is different from that of the natural metals; and it varies over time as the fuel cools, because the radioactive isotopes present are subject to decay. At the time of discharge from the reactor a number of very short lived isotopes are present, but these decay rapidly. The composition after about five years is shown in Table I. With longer times the composition and the total masses of the elements present do not vary significantly,


apart from the conversion of Io6Ru to '06Pd. Some of the isotopes shown in Table I are on-

ly present at low mass concentrations, but they are important because they impart radioactivity to the metal. This radioactivity has important implications for the potential utilisation of the metals, even if they were separated. We shall return to this point later in the paper.

In order to obtain an idea of the potential platinum group metals resource in nuclear fuel, it is necessary to consider the size of present and future nuclear power programmes. It is possible to estimate the total world arisings of fission product platinum group metals from their fission yields and the expected arisings of spent fuel based on forecasts from the Organisation for Economic Co-operation and Development (OECD) and others. Light water reactor data can be used for the calculation because this type of reactor will dominate the nuclear power programmes for the world as a whole. In Table I1 the arisings based on one set of assumptions (2) are compared with annual consumption in the World Outside Centrally- Planned Economies Area (WOCA), and with 1982 estimates of the world reserves. Full details of the calculations are given elsewhere (2).

The data show that nuclear arisings of the platinum group metals are potentially a significant fraction of reserves, and represent many years consumption at current rates. However, the platinum group metals content of the fission product of spent fuel is not immediately available to man. For the metals to become attainable it is necessary for the fuel to be reprocessed. It is thought likely that about half the nuclear fuel from power reactors worldwide will be reprocessed (2).

Behaviour of Platinum Group Metals during Fuel Processing

When spent nuclear fuel is reprocessed, the fuel pins are sheared into short lengths, and the fuel is dissolved away from the cladding into 7M nitric acid. During this operation, the uranium and plutonium oxides that are present dissolve, as do most of the fission products.

There is, however, an insoluble residue which contains some of the platinum group metals. The acid solution is clarified and then passes to a sequence of solvent extraction contactors in which separation of uranium and plutonium from the fission products, and from each other, is carried out. Most of the fission products in the dissolver solution, including the platinum group metals, pass to the aqueous raffinate from the first solvent extraction cycle. This raffinate is subsequently concentrated by evaporation to give high level waste liquor, which is then stored prior to vitrification and final disposal. During these stages further precipita- tion of insoluble material can occur.

Insoluble Residues The insoluble material from the dissolution

stage contains 70 to 90 per cent fission products, together with miscellaneous residues and traces of undissolved actinides. These fission products exist as metallic alloys containing molybdenum and technetium as well as palladium, rhodium and ruthenium. About 4 to 5 kg of residues per tonne of fuel have been found in small scale tests, and fine material (60 pn) is present. The amounts and compositions are variable, and the residues are intensely radioactive, with heat outputs of up to lW/g.

The fraction of the initial inventory of platinum group metals which occurs in the insoluble residues depends on the burn-up to which the fuel has been taken. For high burn- up fast reactor fuel, about 98 per cent of the total expected ruthenium has been found in the residues (3).

The insoluble residues are difficult to treat chemically because of their inertness, and their high radioactivity adds to the difficulty and expense of processing them. Direct high temperature chlorination, or alloying with tin, has been used to bring the residues into solution for analytical purposes (4). It is unlikely, however, that such methods could be scaled up economically.

High temperature processes that are based on extraction with liquid metals have been proposed. For example, molten uraniudchromium or


uraniumhron eutectics extract ruthenium selectively from a solution of the residues in molten magnesium (5). More recently, Japanese investigations have shown that treatment of the residues with lead and a glass-forming material causes extraction of the platinum group metals together with technetium and molybdenum, in- to the lead phase, leaving other impurities in the glass (6).

Recovery from High Level Liquid Waste

For thermal reactor fuel, which is the com- monest type, about two thirds of the platinum group metals are found in the high level liquid waste, and various methods have been suggested for their separation and recovery. The range of the chemical elements present in high level liquid waste spans most Groups in the Periodic Table and the chemical problems of separation are in themselves difficult. Con- straints are imposed by the presence of nitric acid (3M in the raffinate). In addition the solutions are radioactive and can only be processed in heavily shielded, and therefore expensive, plant. If the products are to be suitable for general use the separation from other radioactive fission products, for example, caesium- 137 must be essentially complete. The platinum group metals also have intrinsic radioactivity of their own, and the implications of this will be discussed later. These factors will make it very difficult to devise an economic separation route, even at the relatively high market values of the platinum group metals. Over the past three decades, several approaches have been suggested in the literature, but none of them has yet demonstrated the potential for application on a commercial scale. In the following paragraphs some recent advances in separation technology that might be applied to the problem are briefly discussed.

Ruthenium Ruthenium can be separated from other

metals in nitric acid solutions by oxidising it to the volatile tetroxide, for example with potassium periodate (2). From the data in

Table I, it is clear that ruthenium-106 and its daughter rhodium-I06 are the main contributors to the radioactivity of the platinum group metals fraction. The separation of ruthenium from rhodium and palladium might therefore be a worthwhile objective, perhaps as a preliminary step to the purification of the rhodium and palladium. It would be difficult, however, to achieve the necessary radiochemical decontamination by an oxidative distillation process.

Solvent Extraction Methods Solvent extraction methods could have poten-

tial for the extraction of rhodium and palladium. The selection of suitable extraction reagents requires consideration of the speciation and co-ordination chemistry of these metals in nitric acid solutions. Pate1 and co- workers have studied rhodium speciation in nitric acid solutions (7). Hydrated cations, principally [Rh(H,O),] + are typically present, but in the presence of nitrite ion suc- cessive substitution of the water ligands can occur, giving species of the general formula [Rh(H,O), -,(N0,),l(3-n)+ and ultimately the hexanitrito complex [Rh(NO,),I'-. Anionic species would be expected to be extracted by basic extractants such as amines, and Beer has demonstrated efficient and rapid extraction of rhodium by long-chain aliphatic amines from nitritehtric acid systems in the presence of salting-out reagents (8).

Amine extractants, however, are generally used in the acidity range pH 2-4. In contrast, high level waste contains 1.5 to 3M nitric acid, and its neutralisation before treatment would pose additional process problems.

More recently Davis and co-workers have extracted palladium with a good degree of selectivity from synthetic fission product solutions in 3M nitric acid, using the tertiary amine Alamine 336 in tributyl phosphatekerosene (9).

Other systems for rhodium extraction have also been reported but suffer from various disadvantages. For example, a hydrocarbon solution of the cation exchanger

Platinum Merals Rev., 1991, 35, (4) 205

dinonylnaphthalene sulphonic acid can be used as an extractant (10); backwashing is readily achieved with nitric acid or with a nitrite solution.

Fission product arising

2000

2030

Natural reserves ( 1 982)

Annual consumption in WOCA (1986)

Rh(H,O)6Hnm-,Dnm + 3H+

Note: Bar lines indicate species in the organic phase; HD represents dinonylnaphthalene sulphonic acid.

Ruthenium Rhodium Palladium

364 71 21 8

1423 280 850

3220 770 8520

7.4 8.4 92.0

The extraction mechanism here depends not on ligand exchange, which is generally slow for rhodium, but on inclusion in the micelle structures formed by association of the extractant in the hydrocarbon phase. Rhodium extraction is therefore rapid, but the reagent is not selective for rhodium.

Better selectivity for noble metals can be obtained with extractants containing ‘‘soft’’ donor atoms, such as sulphur. The extraction of palladium (1 1) and rhodium (12) by dialkyl sulphides is well known; but equilibration times for extraction are long (a few hours) making these extractants unsuitable for continuous counter-current solvent extraction processes.

Substituted phosphine sulphides are another potentially useful class of reagents. Alkyl phosphorothioic triamides, (RNH) PS, extract a variety of metals, including palladium (13), from mineral acid solutions. For rhodium

extraction from nitric acid media by the reagents R,PS, when R = phenyl, butyl or C,H,,NH, a fairly polar diluent, such as hep- tanol, is required; extraction is most efficient for the case where R = C,H,,NH and at 2 to 3M nitric acid; and equilibration times are long (3 to 6 hours) (14). The last of these factors suggests the need for a batch extraction process, rather than continuous counter-current extraction, but the efficiency is not high enough to allow a satisfactory recovery by such a method. Tertiary phosphine sulphides (1 5) and oxides (16) have also been used to extract palladium.

By careful choice of conditions, solvent extraction, with a sulphur based extractant, might be used to separate rhodium and palladium from high level liquid waste, but selectivity would be difficult to achieve. The processes would tend to be relatively complex, and plant costs would inevitably be high because of the shielding and remote handling equipment required for dealing with the fission product solutions. None of the processes discussed can currently be regarded as economically viable candidates for industrial use.

Utilisation of Fission-Derived Platinum Group Metals

If a perfect chemical separation of the platinum group metals from other fission products and from each other could be carried out,

Table II

Comparison of Projected Arisings of Fission Product Platinum Group Metals with Natural Reserves and Annual Consumption,

tonnes


the products obtained would still be radioactive because of the presence of active isotopes of the metals themselves, see Table I. This fact places severe restrictions on where and how the separated metals might be used, because of the obvious need to limit radiation doses to workers and to the general public. There is also a danger that if the radioactive metals from fission sources became mixed with material from natural sources, for example during metal recycling processes, the whole inventory of these naturally occurring metals could become contaminated with radioactivity.

Ruthenium Ruthenium separated after cooling for five

years would contain 3.8 per cent of Lo6Ru, giving it a specific activity of 8 Wg. IwRu is a low- energy fl emitter, but its daughter Io6 Rh emits high-energy y rays and has a half-life of 30 seconds. Whenever Io6Ru is present, an equal activity of IMRh exists in equilibrium with it. Such ruthenium is clearly not suitable for widespread application. The metal would become essentially inactive after cooling for 30 to 50 years, but this long wait would involve economic penalties.

Ruthenium is the lowest priced of the three platinum group metals under consideration (17). It is used mainly in electrical applications and as an electrode material. It is not feasible that fission product ruthenium will be separated and used unless there is a dramatic change in the present situation.

Rhodium Rhodium is an essential component of three-

way catalyst systems for the control of automobile exhaust emissions, an application which accounts for 70 per cent of rhodium usage. Expanding demand for this application has led to steep rises in the price of rhodium.

This situation makes rhodium an attractive candidate for separation. In the complete absence of ruthenium, rhodium would be free of I o 6 R h . However, the isotopes lo2Rh and 102mRh, although insignificant in mass terms, are sufficient to give separated rhodium a

specific activity which is too high for general use in the motor industry, see Table I. A cooling period of about 50 years would remove the activity. Alternatively, isotopic separation processes could be considered.

Even at the high market value of rhodium, economic separation and use of fission-derived material does not appear likely with the currently available technology.

Palladium The half-life of the active palladium isotope

present in the fission-derived metal is so long (0.65 million years) that its activity is effectively permanent.

In addition, palladium is not as rare as the other platinum group metals, Table 11, and currently it is relatively modestly priced (17). For these reasons its separation from high level liquid waste will tend to be unattractive.

Conclusion The quantities of the three platinum group

metals, palladium, rhodium and ruthenium, present in irradiated nuclear fuel are sufficient to constitute a useful resource of these important metals. This is particularly true of rhodium, which is currently of great strategic and economic importance because of its use in vehicle exhaust emission control catalysts.

Progress has been made on the development of chemical methods for extracting the platinum group metals from nuclear waste, but the chemical complexity and high radioactivity of the materials involved make it very difficult to devise an economically attractive process.

Even if completely separated chemically from other fission products, platinum group metals derived from nuclear fuel would remain intrinsically radioactive. This would place a severe restriction on their utilisation, unless they were first stored for a period of say 50 years to allow the activity to decay sufficiently.

Acknowledgements The author thanks numerous associates in AEA

Technology, British Nuclear Fuels plc and Johnson Matthey for stimulating exchanges of information on the subject of this paper.


References 1 R. J. Newman and F. J. Smith, Platinum Metals 9 R. G. Schuler, C. B. Bowers, J. E. Smith, V. Van Rev., 1970, 14, (3), 88 Brunt and M. W. Davis, Polyhedron, 1987, 6 ,

2 “Feasibility of Separation and Utilisation of llZ5 Ruthenium, Rhodium and Palladium from High 10 N. M. Patel and J. R. Thornback, “Extraction Level Wastes”, IAEA Technical Report Series ’87”, Institute of Chemical Engineers Sym- 308, IAEA, Vienna 1989

3 D. E. Benker, J. E. Bigelow, w. D. Bond, D. 0. 11 J. E. Barnes and J. D. Edwards, Chem. Znd., Campbell, F. R. Chaltin, D. J. Crouse, R. L. FeuOws’ L’ J’ King’ G* J’ c’ R‘ G’ Ross and R‘ G’ Energy Of Today and Tomomow”, ENC 86 Transactions, 1986, 4, 109

4 H. T. Baker, P. E. Brown, R. J. Pateman and K. L. Wilkinson, “The Characterisation of In- soluble Dissolver Residues and the Development

10823 EN

Technol., 1981, 16, 1071

Technol., 1986, 23, 540

posium Series no.103, 1987

1982, 151 12 P. A. Lewis, D. F. C. Morris, E. L. Short and D.

N. Waters, ’3. Less-Common Metals, 1976,45, 193 13 T. H. Handley, Anal. Chem., 1964, 36, 2467 14 I. Longden, N. M. Patel, J. R. Thornback and J.

H. Miles, Solvent Extr. Zon Exch., 1986, 4, (3), 421

Acad. Sci., Park, 1987,304,889 (b) Y. Baba, M. 5 F. J. Smith and H. F. Mchffe , Sep. Sci. Oshima and K. Inoue, BUN. Chem. SOC. Jpn.,

1986, 59, 3829 6 K. Naito, T. hlatsui and Y. Tanaka, 3. Null. S C i . 16 v. p. Popik and B. N. Zaibev, “Back End of the

Nuclear Fuel Cycle: Strategies and Options”, 7 N. M. Patel, Ph.D. Thesis, University of Proceedings of IAEA Symposium, Vienna, 1987,

8 M. Beer, B. Girski and L. RUSS, East German 17 Johnson Matthey P.L.C., “Platinum 1987” and

ofTreamentMethods”, 1986, CEC report EUR 15 (a) S . D W c h , G. Cote and D. Bauer, C . R .

Loughborough, 1985 p.554

Patent 205,620; 1982 subsequent issues

Platinum Silicide Temperature Detectors During the plasma etching of wafers, the

detection of the end-point is important; in a system comprising polycrystalline silicon layers on a silica/silicon substrate this can be indicated by the temperature. The use of an infrared charge-coupled-device, consisting of a 320 x 244 platinum silicide Schottky barrier detector array, with associated equipment, for thermal imaging has been reported by V. Patel, M. Patel, S. Ayyagari, W. F. Kosonocky and D. Misra of the New Jersey Institute of Technology and B. Singh of the David Sarnoff Research Centre (Appl. Phys. Lett., 1991, 59,

The platinum silicide infrared imager is operated at 30 frames/second, and can detect radiation in the 3 to 5

The results from the platinum silicide Schot- tky barrier detector array were compared to those from the commonly used laser in- terferometry technique for thickness monitoring. It was found that the end-point for etching the polycrystalline silicon could be readily detected, and that the increase in the infrared signal after the silica etching was complete was caused by the heat of the exothermic reaction associated with the etching of silicon in the plasma medium, of carbon tetrafluoride and 15 per cent oxygen at a total pressure of 25 mTorr.

( l l) , 1299-1301).

spectral range.

The etch rates for polycrystalline silicon and silica were estimated to be 2100 and 1040 &min, respectively.

Thus, in addition to end-point detection, thermal imaging can be used for remote wafer temperature sensing, a critical parameter, affecting the etch rate and uniformity, the anisotropy, selectivity, and photoresist integrity.

Palladium Contact Materials The development of a process that enables

palladium-nickel alloy films of accurately controlled composition to be electrodeposited has been reported by scientists at AT&T Bell Laboratories, Murray Hill, New Jersey, (J. A. Abys, H. K. Straschil, I. Kadija, E. J. Kudrak and J. Blee, Metal Finish., 1991, 89, (7), 43).

The formulation of the bath depends upon the intended plating operation and the alloy required. While temperature, pH, current density, and solution agitation all influence the composition of the electrodeposit, the key factor is the palladiummickel ratio of the bath. The bath is generally operated at about 35OC, and at a neutral to slightly alkaline pH.

Deposits range from 10 to 30 weight per cent nickel. They have excellent appearance and bulk thermal stability; they are very ductile, harder than hard gold and low in contaminants.


3 D. E. Benker, J. E. Bigelow, W. D. Bond, D. 0. Campbell, F. R. Chaltin, D. J. Crouse, R. L. Fellows, L. J. King, F. G. Kitts, J. C. Mailen, R. G. Ross and R. G. Stacy, “Nuclear: Energy of Today and Tomomow”, ENC 86 Transactions, 1986, 4, 109

Second Grove Fuel Cell Symposium PLATINUM-BEARING FUEL CELLS EMERGE AS INITIAL CHOICES FOR COMMERCIALISATION

By David G. Lovering Consultant, Swindon, Wiltshire, England

In the year in which the bicentenary of the birth of Michael Faraday is being celebrated, a second Grove Fuel Cell Symposium was held at the Royal Institution, London, from 24th to 27th September, 1991. Following the Introduc- tory Discourse, around two hundred and fifty delegates, mainly from Europe, Japan and the U.S.A., listened to twenty-six papers, address- ing the theme of “Progress in Fuel Cell Com- mercialisation”. After the opening Keynote Review on future prospects for fuel cells, individual sessions examined market development, commercial initiatives, manufacturing and systems development, transport applications, and concluded with visions for fuel cell exploitation in the twenty-first century. Apart from alkaline (AFC) devices, which contain high platinum loadings and which are considered to be fully developed with mainly specialised applications for space and military use, phosphoric acid (PAFC) and solid polymer (SPFC) types are now becoming available commercially from U. S., Japanese and Canadian suppliers; these also use relatively high platinum group metal loadings. Once again, the superior catalytic activity of platiniferous metals is aiding the development and introduction of this entirely new technology.

This conference brought together international figures actively concerned with introduc- ing fuel cells into the market place. Thus, speakers were drawn from leading developers and utilities in the U.S.A., Japan and Germany but also included four contributions from the United Kingdom. Dutch, Italian and Canadian interests were again represented with Spain emerging as an interested party. The level of interest in, and future prospects for, fuel cells was demonstrated by the large attendance.

The meeting was formally opened on Tues- day evening by Dr. G. J. K. Acres, Chairman of the organising committee, and Professor A. J. Appleby of Texas A. & M. University, well- known for his advocacy of fuel cells and sometime presenter of submissions on the subject to U.S. Government assemblies. Professor Appleby then introduced Dr. Francis “Tom” Bacon, who had devised, constructed and operated the world’s first viable fuel cell more than half a century ago. Tom has received many awards in recognition of his pioneering work including an O.B.E., F.R.S. and Fellowship of Engineering - on this occasion he was presented with the first Sir William Grove Medal, cast in platinum. In accepting the medal, Dr. Bacon recalled his numerous col- laborators and recounted the continuous battle for funding that he had experienced over many years. He had been lucky, felt his efforts had been worthwhile and encouraged persistence with future fuel cell development.

Following this presentation, Ing. K. Swart, former Managing Director of the Shell Group, gave the introductory discourse on “Trends in the Energy Market after World War 11”. This drew heavily on his experiences in the oil industry which has dominated post-war development in the West. Notwithstanding, Swart was able to identlfy the major socio-political and economic influences over national development, which might point the way forward to a more rational future energy strategy. While oil had initially shown the strongest growth trend in the energy sector during the post-war period, gas finds offshore and in the U.S.S.R. had made a sizeable impact more recently, at the expense of coal utilisation; nuclear capacity had risen to about 20 per cent of energy supply.


Electricity had grown steadily as a percentage of the stationary energy generation market. Similarly, as living standards had risen, demand for travel in general and private transport in particular, had grown to monopolise oil supply, requiring conversion of plant to crack more heavy fuel oils to light fractions. He pointed out that the oil supply hiatus in 1972 was a political crisis, and predicted that it was this aspect of human endeavour which would remain least predictable in the coming decades. Environmental issues were now of concern in the West, requiring higher energy efficiency to reduce the pollution burden, although it would be unreasonable to expect constraint by the developing world in this area.

For the future, Swart warned that “nothing can grow forever without . . . major problems’’. Thus, the growth in demand for electricity, lowered by recent improvements in the efficiency of end-use devices, would again increase. Energy demand in Eastern Europe and South East Asia would continue to accelerate. Coal and gas should be retained to prevent dependence on oil, with gasification a promising technology. Governments should sponsor steady research, design and development, and efficient technologies, using the wealth generated from energy taxation. Long term strategies were required - “stop-go” policies were inappropriate. Of all the most promising new technologies, Swart would support biomass for sustainable energy resource. During his address he had deliberately avoided mention of fuel cells. His final comment advocated electrochemical energy conversion as the best contender to meet the needs of a clean, efficient future for both the presently rich and the poorer nations.

At the start of the technical proceedings on the Wednesday morning, the Chairman, Dr. G. J. K. Acres of Johnson Matthey introduced W. P. Teagan of Arthur D. Little, who gave the Keynote Address, based on recently commis- sioned studies, entitled “The Role of Fuel Cells in the Future Energy Scene”. Teagan’s talk was illustrated with data showing predictions for energy growth according to some of the

many suggested scenarios. Again, it was the expected doubling in demand for energy by the developing nations that provided one focus. Although their per capita energy consumption rate would remain relatively small, with their expected population growth an increasing world environment burden would become apparent, with carbon dioxide the most insidious contributor to global warming. Present projections predict only modest improvements in energy efficiency, whereas selection of specific advanced technologies, most notably fuel cells, could dramatically reverse the trend; this would be especially so if end-use efficiencies were raised and electric vehicles were adopted. A Table showed reductions between 20-70 per cent of primary energy sources across the spectrum of possible uses as a result of fuel cell introductions. In large scale stationary applications, cost benefits of fuel cells were compared with alternative advanced technologies; turbines and clean coal devices may prevail in the next decade, especially as multi-MW fuel cells are in their infancy. In smaller and dispersed applications, cogeneration and combined heat and power (CHP) will become important. Here, the innate efficiency, flexibility, modularity and low emission of the fuel cell would be crucial since the types of competing plant to cover this range, when fitted with emission controls, are equally or more expensive. Traction applications are further away and more demanding, even though present developments are both exciting and promising.

Requirements across the market sectors for power generation equipment were outlined in order to evaluate the overall market size; this led to projections of a total of 800 GW, with 580 GW of new capacity, needed within the decade, of which 55 per cent would be centralised. Assuming a 5-15 per cent market share for <50 MW capacity, fuel cells could fulfil 4 GW/year by the year 2000 in stationary applications. This would depend on their achieving reliability beyond 25,000 hours, efficiencies of at least 40 per cent (HHV to electricity) and approximate costs of $1500-1700kW for early models and $1200/kW for mature models.


The recipient of the first Sir William Grove Medal, Dr. Francis “Tom” Bacon started to become interested in fuel cells in 1932, and spent some years looking into their early history, including the work of Grove and Ludwig Mond. Dr. Bacon started to work on fuel cells at Kings College, London in 1940; his work was continued in various departments at Cambridge University, supported by the Electrical Research Associa- tion, and later the National Research Development Corporation this being undertaken at Marshalls Airport Works, Cam- bridge

Finally, Teagan addressed the availability of the necessary high value materials to meet the manufacturing requirements of the various fuel cell types. Due to the gradual lowering of platinum loadings in PAFCs, this now ac- counted for only $60-70/kW stack costs, so that 4 GW installed by the year 2000 would only require 14 per cent of platinum production, or 500,000 ounces which is well within the capability of the industry. Contentiously retur- ning to the political theme, he was concerned about government (sic) largesse towards competing military technologies such as nuclear and aerospace-derived gas turbines. Governments need to be aware of the prospects offered by fuel cells and directly fund early commercialising efforts. So far, fuel cells had been relegated to a “well-kept secret”; this had to be reversed.

Development of the Market The morning programme was continued with

three contributions describing the market possibilities for fuel cells in Europe, America

and Japan. M. C. F. Steel of Johnson Matthey began by updating his Company’s 1985 study for the Commission of the European Com- munities with an altogether more optimistic prospect. In the European Economic Com- munity, the 5 per cent growth of electricity demand to 350 GW in the 1970s, had fallen back to 3 per cent by the mid-1980s, and was now approximately 1-2 per cent. Similar trends had occurred throughout the rest of Europe, except that there the growth rate remains at 2-3 per cent. Additional growth into the next century could remain around 2 per cent overall, although - 140 GW of replacement plant will be required by 2010. Steel then outlined the limits to growth for nuclear plant post- Chernobyl and for hydro-electric on environmental grounds. These factors profoundly affect the energy policies in Italy, Germany, Austria, Netherlands, Sweden, Norway and Spain - some on both counts. Acid rain considerations were strongly influencing German and Swedish policy against thermal cycle plant.


Thus, two strategies towards fuel cell demonstration and introduction in Europe were emerging: one involving the purchase of available Japanese or American stacks or plants, and the other in attempting to develop an all-European technology. According to the first option, Milan was due to demonstrate an International Fuel Cells Corporation (I.F.C.) 1 MW PAFC stack in 1992, using a Haldor- Topsqe reformer and Ansaldo plant, this being the largest system presently envisaged in Europe. Elsewhere, I.F.C. 200 kW PAFC units were destined for Germany, Sweden and Den- mark; a Westinghouse 400 kW PAFC would be hybridised into a Norsk Hydro chloralkali plant; Fuji Electric PAFC plants of 50-200 kW were scheduled for Italy, the Netherlands and Germany (the latter for Solar Wasserstoff Bayern’s (S.W.B.) solar hydrogen project), while Energy Research Corp. (E.R.C.) MCFCs would be supplied to the Danes and Germans (through Messerschmitt Boelkow Blohm (M.B.B.) - a shareholder).

Alternatively, AFC and solid oxide (SOFC) technologies are already available in Europe, the former at Elenco, Siemens, GEC Alsthom and in Austria, the latter at Asea Brown Bouveri (A.B.B.), Dornier and Siemens, among others. Meanwhile, the Dutch have established a strong presence in MCFC using Institute of Gas Technology (I.G.T.) codigura- tions, M.B.B. will construct 2 MWlyear of MCFC using E.R.C. designs, with Spain and Sweden also actively promoting this high- temperature cell. The most promising SPFC technology was being acquired by Germany, Italy and the U. K. amongst others. Steel defin- ed the European markets for fuel cells and concluded optimistically, suggesting fuel cell interest was now being converted into action.

E. A. Gillis of Electric Power Research In- stitute (E.P.R.I.), California, provided a com- prehensive account of fuel cell development during the last three decades; this had culminated in a lack of user acceptance. He felt that fuel cell commercialisation had been retarded by a failure of potential users to fully appreciate the benefits. Head-to-head cost com-

petition is problematic for any new technology unless niche markets are available. However, a radical change is now underway in the U.S.A., with publication of the Clean Air Act. This will deliberately distort energy market forces by direct government interference which has become necessary to prevent further environmental decay. The law particularly affects sulphur dioxide emissions nationwide, but is region-specific for nitrogen oxides and ozone reductions. The requirement for 2 per cent zero-emission vehicles ordained for California has been internationally publicised. A more subtle consequence of the Act surrounds the trading market established in emission allowances. If any organisation underscores its target, then the balance of emissions permitted can be sold elsewhere. Thus, the installation of virtually zero-emitting fuel cells could lead to substantial rewards over and above those accruing from lower maintenance, higher efficiency, etc. Furthermore, additional environmental legislation is in prospect, certainly including carbon dioxide emissions. Together with regulations, yet to be enacted, on mandatory fuel substitution and restriction on electrical transmission systems, the tangible benefits of fuel cell technology promise to bring immediate financial reward since their attributes would become quantifiable. Both utility and transport could expect to benefit.

The logical approach to fuel cell commercialisation being adopted in Japan was outlined by A. Fukutome of the National Energy Development Organisation (N.E.D.O), Tokyo. Attractive applications had initially been identified, time and size targets had been determined, then resources had been directed towards the necessary research, design and development to achieve those goals. In the first part of this approach, government agencies had established the break-even costs for fuel cells in utilities (dispersed, centralised and remote), for on-site cogeneration and in industrial and transport sectors. Next, the market was assessed for dispersed PAFC in CHPkogeneration modes in both industrial and residential sites; the commercial sector alone would require


2.4 GW/year in the 2000s, amounting to about $150m/year in platinum sales according to Teagan’s formula!

M.I.T.I. had contributed with a long range study of Japan’s energy needs: energy saving and a 70-fold increase in fuel cell introductions by 2010 were advocated. At present, two different 200 kW and one 1 MW PAFC plants had been developed for N.E.D.O. as well as an advanced 5 MW sized turbo-compressor. Both square and rectangular MCFCs have been developed, the former up to 25 kW for pressurised operation; 100 kW designs were scheduled for 1991 and 1993, respectively. Meanwhile, a 5 kW internal reforming MCFC was being studied. Associated balance of plant technologies for 1 MW MCFC are being developed. Four planar and one tubular SOFCs are being evaluated - scale up to tens of kW are envisaged in a new programme.

For the future, N.E.D.O. is beginning a new five year PAFC programme to develop a 5 MW pressurised and a 1 MW unpressurised plant. In addition private sector activities, including the 11 MW demonstration unit from Tokyo Electric Power Company (TEPCO)/I.F.C., were proceeding. Goals still remaining are cost reduction and reliability, and provision of economic, political and infrastructure support.

Commercial Initiatives Chairing the afternoon session, Dr. A. L.

Dicks of British Gas called upon J. A. Serfass of Technology Transition Corp. and D. R. Glenn of E.R.C. to jointly outline their co- operative approach and progress in the American Public Power Association’s (A.P.P.A.) Notice of Market Opportunity (NOMO). In this unique venture, E.R.C. had successfully responded to A.P. P.A. ’s invitation to develop multi-MW fuel cells in a shared part- nership leading to a product available for Public Power members in the mid-1990s. Initially, a 2 MW gas fuelled, internally reforming MCFC had been selected for trial. A document of “Principles . . . for Commercialising . . . Fuel Cell(s) . . .” delineated the respective respon- sibilities of the supplier and the users, and

included agreed milestones, risk and royalty sharing as well as user commitment and incentives.

Technically, a fuel cell with a projected heat rate of 6350 BtukWh at 54 per cent efficiency (LHV), operating at 1200OF, should be constructed at a cost of $lOOO/kW (1990 $); a later version should have a lower heat rate, higher efficiency, be water-independent, but will cost more. Longer term targets anticipated 100 MW units and coal-gas fuelling. The first demonstration should begin this year, with the first unit operating in 1994, with 100 MW of initialled orders by the end of that year at $lSOOkW. These are early target dates which could accelerate MCFC displacement of PAFC if met. The NOMO is now supported by twenty-three utilities, with a hope to raise this to thirty-five. Santa Clara is the lead demonstrator, obtaining financial and technical support from E.P.R.I. and other south west Pacific Coast interests. A 20 kW stack with full balance of plant has been successfully tested, grid-connected, by Pacific Gas and Electric (P.G.E.) at San Ramon.

J. Doelman of N.V.Nederlandse Gasunie focused on CHP applications of fuel cells in a Dutch context and from the viewpoint of a gas utility. While gas prices are State regulated and differ for domestic and industrial consumers, there already exists some commonality between gas and electricity distribution companies who may themselves be electricity generators. Fur- thermore , some energy-intensive and chexnical industries are already CHP users, with Gasunie support, but cheaper electricity had blocked further moves to grid independence. Not- withstanding, Doelman foresaw the small, dispersed CHP market as the best growth prospect for fuel cells, especially as they offered a diminished carbon dioxide inventory, coupled with very low nitrogen oxides emission. He illustrated the other perceived advantages of fuel cells by reference to PAFC, suggesting that claims of efficiency, modularity and variable heat/power ratio were suspect, whilst reliability was unproven. The efficiencies of MCFC and SOFC were not without attraction, if


overstated, but these technologies were not yet mature. Nevertheless, the integrated systems described by Blomen, see below, could lead to very high overall electrical efficiencies. Gas utility experience with presently available tur- bine and engine CHP plant will prepare for later fuel cell demonstrations.

K. Shibata of Tokyo Electric Power Com- pany (TEPCO) painted a more inspiring and bullish approach. The Company had actively participated in demonstrating PAFC technology for many years with the result that Japan expected to install - 1 GW capacity by 2000. All aspects of installation and testing had been examined since the early United Technologies Corp. (U.T.C.) 4.5 MW design in 1981: the International Fuel Cells Corpora- tion (I.F.C.)/Toshiba 11 MW, the Sanyo (air- cooled) 220 kW and the I.F.C. 200 kW units had now begun trials. Two pre-prototypes of the latter design had accumulated around 7000 hours and 10,000 hours of satisfactory operation, although their gradual decline in performance requires improvement. The second of these had been incorporated into the district heating plant at Shibaura in order to assess its capability for various heating and cooling functions. Emissions were very low and maintenance tasks routine.

The 11 MW PC-23 I.F.C. PAFC has now begun trials at Goi; palletised, pre-assembly modularised design reduced site construction time to just over 1 year. Process and control testing had been completed in two-thirds of the allotted period, which included run-up to stand-by readiness on a 30 per cent simulated load. Full output was achieved on April 26th 1991, with all specifcations being met or ex- ceeded. Gross HHV efficiency was 43.6 per cent, with nitrogen oxides emission at 1 ppm. At July 31st, 1991, some 927.5 hours of operation, amounting to 6598 MWh had been recorded, although during his lecture Shibata was able to update that to 1414 hours of operation (875 hours continuous) providing 10,263 MWh of power (presumably mid-September 1991 data). Only minor maintenance had been required so far. Testing is to continue for two

years in order to confim reliability, flexibility and heat utilisation characteristics in the dispersed power supply, CHP mode. It later emerged that TEPCO is now considering an ex- tension of testing beyond 10,000 hours. In spite of early successes, cost reduction remains a major goal; some will come from automated mass production, but additional innovation, especially in the stack, is desirable. International co- operation would be the cornerstone of successful introductions of fuel cells to the market. The present successes with platinum-based PAFC plants, would be a prelude, however, to later MCFC and perhaps SOFC technologies, in which T E E 0 is now beginning studies.

J. Packer of Combined Power Systems proposed that fuel cells could become viable in the small-scale CHP market, especially following the 1983 Energy Act in the U.K. which had stimulated demand. Packer enumerated the key elements of a CHP system together with their typical present applications. Based on the perceived advantages of fuel cells, he indicated that they could become the only prime mover in sub-30 kW systems, as well as having certain attractions above that rating. Through-life costs are more important than capital costs; security and stability of the manufacturer are equally important for assured endurance. Nevertheless, it is too early to obtain accurate information on fuel cell reliability, hence field demonstrations are urgently required. Detailed technical for- mulae were provided for assessing fuel cell cost- benefits; these showed up to four-fold savings compared with conventional sets, allowing over three times higher installed costs with greater payback. Lifetimes needed to achieve 40,000 hours. Analysis suggested that SPFC units, using platiniferous catalysts, could meet the requirements for low pressure, hot water systems. Packer raised many questions concerning fuel cell suitability and, in spite of later discussion which tried to define who the “cu~tomer” was, he indicated that he was a purchaser on behalf of his power-using clients. In the complete package, users were not concerned as to the means of power generation- only cost and reliability.


R. Vellone of ENEA described the present status of Italian fuel cell programmes. Like Japan, the nation depends on imported fuel and like Sweden, it has voted against nuclear power. Since coal is environmentally problematic, natural gas fuel cells providing 4-15 GW capacity by 2010 appear attractive, particularly if deployed in dispersed mode. The Government’s National Energy Plan is supporting growth of municipal electric utilities and equipment suppliers. As an early step, some 0.25-1 MW on-site fuel cell capacity is envisaged: additional focus on transport applications is underway. In Milan, the 1 MW PAFC I.F.C. stack has been installed and engineered by An- saldo at Bicocca, supported by Milan Energy Municipal (A.E.M.) and ENEA, and using a Haldor-Topsye reformer. Testing is planned for 1992 prior to full commissioning at the end of that year. Elsewhere a 25 kW Fuji PAFC has been engineered by Kinetics Technology Inter- national (K.T.I.) near Rome and a similar 50 kW unit near Milan. In 1992, an I.F.C. 200 kW PAFC will be constructed by Ansaldo, in Bologna in co-operation with ENEA and the Commission of the European Communities (C.E.C.) THERMIE programme. Small generators in the range 1-5 kW are also under study.

Ansaldo has designed, built and tested a 1 kW MCFC stack and will co-operate with I.F.C. towards a 100 kW plant for 1994. Ginat- ta is bringing its extensive experience of molten salt and electrochemical systems to bear on internal reforming MCFCs. A number of col- laborative SOFC programmes are underway, including C.E.C., JOULE and BRITE ven- tures and a CNR-TAE-U.S. S.R. co-operation. SPFC development for transport applications is making rapid progress at de Nora towards a 10 kW stack for 1992; in the meantime, ENEA will evaluate a 4 kW Ballard stack. A well co- ordinated series of government funded programmes across the spectrum of fuel cell types and applications is gathering pace in Italy.

In an extra paper to the programme, G. J. Sandelli of I.F.C., co-author R. J. Spiegel of the U.S. Environmental Protection

Agency (E.P.A.), reported an interesting new application for fuel cells in energy recovery from landfill gas. A Phase I study of the concept had begun in January 1991 at I.F.C. under an E.P.A. contract. Phase 11, starting in September, concerned construction and testing of the four 200 kW PAFC plants required for the 800 kW module, including operation of the critical pretreatment plant designed to remove catalyst poisons such as sulphur and halides. Phase I11 would entail demonstration at Penrose, California, around January 1993.

Sandelli indicated that this application offered several benefits simultaneously over present practice; thus, methane consumption would mitigate one contribution to atmospheric pollution and global warming, and heat and power would be generated competitively in high energy cost locations, providing new revenue for site owners.

Manufacturing and Systems Development

On Thursday morning, Mrs S. Fleet of the U.K. Department of Energy, introduced R. Anahara of Fuji Electric, who described the continuing progress in PAFC manufacturing in his Company. So far, 17 demonstration plants, totalling 2 GW of capacity had been supplied. A further 63 plants totalling 9.7 MW capacity were expected to be ordered; one for Korea had only just been ratified in the previous week. Of these, the largest are the 5 MW PAFC units, designed for pressurised operation and destined for electric utilities. Construction times would be under four years. The improved 0.8 m2 electrodes had superior performance to those used in the 1 MW developmental models, with a voltage decay of only one-third of that projected for 40,000 h life in the first 5000 hours and a mere one-fifth in the next 5000 hours. Over 70 sets of 50 kW and 100 kW were planned, four for Europe, with a total capacity -4.7 MW. Ten such cogenerating plants are presently in operation in Japan, including six sets under test at Rokko, for Kansai Electric. Power densities approaching 5 kW/m’ have been achieved. Equipment improvements and system


simplifications would lead to cost reductions, particularly with mass production.

Apart from natural gas, Fuji has also developed methanol, liquified petroleum gas and naphtha fuelled plants; methanol was favoured for remote sites and transport, since it could be stored and transported as a liquid at ambient and could be reformed at low temperature ( - 3OOOC). Presently, three 50 kW PAFC sets are under construction for the U.S. Department of Energy bus demonstration. Anahara was confident that Japanese Govern- ment support, through M.I.T.I.’s Long Term Energy programmes, was providing the correct framework for successful fuel cell introductions. Aggressive acceleration of PAFC development in co-operation with utilities and government agencies would soon lead to a viable commercial product.

Recent progress achieved in SOFC technology by Westinghouse Electric was described by W. J. Dollard. Their configuration was based on tubular cells, with direct reforming of natural gas or coal gas and cogeneration with coupled thermal-cycle plant to use the high-grade exhaust heat. Following the recent trials of two 3 kW sets in Japan, a further two 25 kW units were under construction for imminent delivery. Small bundles had demonstrated 5000 hours of operation, with single, laboratory cells exceedmg 20,000 hours. Scale-up of the present 50 cm long cell to 100 cm was initiated this year, which would enable plants to be constructed with outputs of hundreds of kW, longer cells were required for MW units. The U. S. Department of Energy is supporting a further five year development programme with $64m, with a view to demonstrating a 2 MW plant in 1995. L. J. M. J. Blomen of K.T.I./Mannesmann,

The Netherlands, outlined a decade of fuel cell related systems development, culminating in the construction of two 25 kW and one 80 kW plants using imported stacks. Their market surveys had suggested that small (-25 kW) fuel cell systems become competitive at production levels of a few hundred, while 250 kW sets achieve viability at a smaller volume rate.

Above 3 MW sizing, advanced thermal cycles are competitive if environmental constraints are ignored. Decentralised stations of - 100 MW could also show cost-benefits in favour of fuel cells.

The first (Engelhard) 25 kW PAFC had now been dismantled for analysis after one year of operation. The second unit (Fuji stack) had been installed at Delft, but was compromised by water ingress and had to be rebuilt. A third unit for ENEA had also been delayed during the recession. An 80 kW unit, incorporating Fuji stacks, has been installed and successfully started in Bavaria in the S.W.B. advanced solar storage-electrolysing hybrid fuel cell plant; early data confirmed operation within specification. Present strategy envisaged capacity expansion, increases in sizing to 1-10 MW together with substantial cost reductions arising from acquired experience and economies of scale; only 1-3 units of 10 MW need be ordered to achieve $1500/kW, whereas a production run of 50 units would be needed at the 250 kW size to attain this costing. Hybridising fuel cells with rotating machines could bring electrical efficiencies above 60-65 per cent. The market share for such plant would depend on the extent of the growth in dispersed installations: transmission costs could be determining.

C. M. Seymour of Vickers Shipbuilding & Engineering Ltd., (V.S.E.L.) related details of a long-term, joint venture with CJB Developments to package power systems based around Ballard SPFC stacks. Markets included military, on-site small commercial and transport, the project being applications driven. Information sharing with Ballard would bring hardware improvement benefits. With reasonable market penetration, this should add another new outlet for platinum catalysts, especially as other more exotic substitutes capable of operating at low temperatures (80-12OOC) would prove too expensive, if available.

Initially, a 20 kW methanol-fuelled device would be demonstrated; other fuel compatibility would be introduced later. In designing the total system, conflicting aspects of good


engineering practice, performance optimisation and costs had to be rationalised. Thus, a model had been devised capable of accepting data variables emanating from stack trials. Other stack testing aimed to establish performances on synthetic reformates and in the presence of carbon monoxide. Applications studies were examining fuel cell/battery hybrid systems, auxiliary and field generators, submersibles and extended duration air-independent power systems for submarines. A target specification for market acceptance of SPFC technology was provided; if met, acceptance could occur within five years. Notwithstanding, a 5 kW stack was operated during the Symposium in the “static” exhibition, where it powered one of the famous Emmett models.

H. Wendt of the Chemical Technology In- stitute, Darmstadt, reviewed past and present developments in fuel cells in Germany. Ac- tivities were being funded and co-ordinated by the Government in collaboration with industry; an DMSOm (-W7.5m) programme had been initiated this year, and included both SOFC and MCFC technologies. Being a 13 per cent shareholder in E.R.C., M.B.B. - part of the Daimler-Bern empire - would participate in the construction of their 2 MW/year pilot manufacturing facility in the U.S.A., under a license agreement. Some of the 100 kW MCFC demonstration units produced would go to Ger- many and would be fuelled by both natural gas and coal gas.

Dornier, Siemens and A.B.B. are engaged in SOFC development, the former two on flat- plate designs, the latter on a thin-layer type. It was hoped that these companies could test kW stacks within three years.

The last paper in the morning session by E. H. Cainara of M-C Power directly addressed that Corporation’s aim to build and sell I.G.T. internally-reforming, internally-manifolded IMHEP MCFC plant, fuelled by natural gas. The attractions of this design are compelling: carbonate electrochemical pumping by differential migration in the stack is eliminated, gas sealing is enhanced, less corrodible pipework is required and dimensional changes

during operation are automatically accom- modated. Market entry sizing would range from 500 kW to 3 MW both for on-site and dispersed loads. 30 to 50 MW centralised, baseload plant with coal gasification could follow. .Initialled orders by 1995 could be filled by 1997. The Burr Ridge manufacturing facility would produce 3 MW/year. An industrial support group/alliance (ACCT) had been formed to monitor the technical aspects and provide market intelligence. Since incorporation, M-C Power had this year assembled and tested a 70 cell stack, and confvmed stable performance. A 10 ft2 stack is under construction for testing this year as a prelude to a 250 kW proof-of- concept plant for 1993. Technical milestones include field trials in 1995 and 1996, following integrated systems verification during 1993-94. With Ishikawajima-Harima-Heavy-Industries (I.H.I.) balance of plant technology th is MCFC variant may offer the winning combination, subject to lifetime and cost considerations.

Transport Applications The afternoon’s proceedings were chaired by

C. M. Seymour, who introduced P. G. Patil of the U.S. Department of Energy. Fuel flexibility, energy saving and environmental benignity were driving forward a strong government-led programme which aimed to advance fuel cell technologies through research and development, optimisation and scale-up, to demonstration in cars, trucks, buses and locomotives. This fervour was imperative for the 130 million Americans whose air quality was below the national standard.

In the immediate future, a methanol-fuelled PAFC powered bus with diesel performance but with a 99 per cent reduction in emissions would be constructed for 1996. Analysis indicated this vehicle would be entirely viable economically during its life-cycle, even though higher initial costs were envisaged. Both E.R.C. and Fuji had engaged in Phase I, proof of feasibility studies, with Fuji selected for Phase 11, power plant integration into buses.

For cars and vans, SPFC units were proposed for mid-term goals, and possibly SOFC later.


General Motors, Los Alamos National Laboratories, Ballard Power Systems and Dow Chemical were examining design concepts for 1993 based on a 10 kW stack, to be scaled up to 50 kW in later phases. The attractions of SOFC lie in potential weight and volume reductions accrued by internal reforming, but 2010 is the earliest target date. In the meantime, reformer technology developments need to address sizekost reduction, start-up and load- following, as well as fuel (liquid) flexibility. In order to compete with internal combustion engines in the 10-40 kW range, which cost $15O/kW, fuel cell systems should show savings in operating and maintenance costs and environmental nett credit. Notwithstanding, the National Energy Strategy group foresees fuel cell propulsion systems as a route to better energy security.

More detailed data on SPFC development, including improved power density, air operation and synthetic fuelling were provided by K. B. Prater of Ballard. A 35-cell stack, built with the latest Dow membrane, could sustain 5 kW on 50 psig air or 10 kW on 30 psig oxygen, with 2000 hours of operation now accumulated. The absence of gas permeability changes in the membrane during this period suggests that long life may result. An earlier 35-cell stack had successfully completed vibration testing, simulating SO00 miles of operation in a bus.

The Canadian and British Columbia Govern- ments were funding Phase I of their bus project with C$4.84m for completion in 1993; on-board hydrogen was chosen as the fuel to avoid the cost, weight and maintenance expenses of a mobile reformer. Twenty-one stacks of 5 kW each, delivering 75 kW to the wheels, are to power this 16-seater coach. Separate trials demonstrated immediate start-up from 3OC, with 50 per cent power in 45 seconds.

In a departure from purely fuel cell considerations, M. Appleyard of Lucas described the important parallel developments occurring in advanced batteries and electric drive systems. In the near term, advanced lead-acid and sodium-sulphur were considered closest to providing acceptable performance for the

proposed “zero-emitting” electric cars. The advantages conferred by hybrid power plants were considered for auxiliary units as low as 2-3 kW, in respect of both range and performance. While the supplement might be internal combustion engine-based, such a combination would no longer be zero-emitting and could in- cur unacceptable cost, weight and volume penalties. The SPFC might meet this challenge if cost, performance and lifetime targets were achieved.

An additional contribution to the programme, by P. L. Adcock of Loughborough University, concerned the prospects for the use of fuel cells in electric vehicles. Based on a real city-to-city power requirement duty cycle, a SPFC (5 kW)-nickelkadmiurn battery (200 kg, 50 Wh/kg) hybrid power pack could provide a 400 km maximum range at 65 km.p.h., derated to 100 km per 5 hour rest period under mixed driving conditions. These figures pertain to methanol fuelling, with 70 per cent reformer efficiency, leading to a 50 per cent reduction in carbon dioxide emission compared with an internal combustion engine and negligible emissions of other pollutants. Alternatively, use of an iron-titanium hydride hydrogen storage system would reduce mobile emissions to zero at the expense of a 50 per cent reduction in range.

In the final paper of the day, K. Strasser of Siemens extended his account from the First Grove Fuel Cell Symposium concerning the Company’s development of fuel cells as air- independent propulsion systems for submarines. Having sailed with AFC power in 1989, Siemens now saw SPFC as a better prospect and were actively developing plant based on these. Stacks had undergone more than 300 on-off cycles of testing with hundreds of hours on standby, cold start-up at full load from 3OoC and low loading down to 3 per cent without observing any deterioration. The revolutionary suggestion that these same cells could be reversed into the electrolyser mode and used to charge a hydride store off-peak was offered; Strasser considered that materials problems were not insuperable, and metal shields might


be used in the construction of the stack. While no cost reduction could be envisaged for SPFC in low volume military and aerospace applications, the substantial markets for electric vehicles and emergency power supplies could introduce the necessary incentives, especially if backed by increasingly stringent emissions regulations. The principal attractions of SPFCs included their advantageous overload capability, extended lifetime with low performance decay rate, reasonable operating temperature range and carbon dioxide-tolerance. Apart from naval applications, the Company envisaged SPFCs as well-matched for land trans’port due to their compatibility with regenerative and energy storage systems-probably superior to advanced batteries such as sodium-sulphur, if hydride storage and air oxidant were employed in 40 kW units. In 1994, Siemens planned to demonstrate some of this advanced equipment in a forklift truck.

Beyond the Year 2000 Technical and Commercial Visions

Planned as a preview for the utopian future, this f d session on the Friday morning was introduced by Professor B. C. H. Steele of Im- perial College. A. J. Appleby of Texas A. & M. University began proceedings with a brief history of innovation in fuel cells from Mond and Langer in 1892 to the 20 kW E.R.C. MCFC for P.G.E. today. He then compared state-of-the-art fuel cells, showing the inherent performance advantage of AFCs (high platinum metals loadmgs); however, their efficiency was degraded after fuel required for reformer heating was included, leaving MCFC as the most efficient overall, especially in the internal reforming mode. Often the equation was reduced to plant costs versus attainable emissions. Innovative combined cycles could achieve nitrogen oxides emissions of 23 ppm, but MCFC would always win, presently producing less than 3 ppm. Power densities of fuel cell systems were too low at approximately 1 kW/m2 (the target was 1.8 kW/m2) and costs were too high at Y193,00O/kWy cost reduction will beUinade by increasing current density.

As for MCFCs, there had been rapid progress, but again the power density was too low. Anodes and bipolar plates might revert to copper-based materials: cathode dissolution ap- peared to be the only serious problem remaining and eventually this would be overcome. Using coal as feedstock in a chemically integrated gasifier, efficiencies of approximately 66 per cent could be achieved at 100 per cent utilisation. The SOFC was still embryonic and many advanced structural concepts were being examined-they were eminently suited to integration with complex and efficient plants, such as that envisaged by the (non-fuel cell) “integrated energy facility” in a recent E.P.R.I. report.

New solid electrolytes were under active consideration and it might be possible to devise an alkaline ion-exchanger based on carbon dioxide-rejecting amines. In this way, weights could be reduced and power densities increased, with the rewards of lower Tafel slopes and higher outputs accruing from AFCs. More than 5 Ncm2 might be achievable from AFCs; this figure had certainly been achieved in SPFCs, even with advanced, low platinum metals loading (0.3 mg/cm2) electrodes.

For vehicle applications, atmospheric air had to be used to avoid the need for pressurisation energy. Here, some 0.3 Akm’ at 0.6 V had been achieved in SPFC at 0.4 mg/cm2 loading. A brief reference to the Billings car suggested that the range claims were exaggerated, but calculated performances might still be acceptable. Use of U.T.C.’s edge current-collecting configuration might be appropriate, since the bipolar plates could be substituted with plastic separators.

Appleby did not doubt the future with a hydrogen economy. Initially, reformed natural gas would be used, but this would later be displaced by electrolyser systems. Significantly, this could herald a return to the platinum- bearing AFC.

Finally he foresaw an all-gas house with a small (2 kW?) base-loading fuel cell, battery peaking and inefficient reformer supplying hot water and space heating.


Raising the spectre of perhaps the best- publicised and most urgent need for a cleaner, fuel cell-driven future, A. C. Lloyd of South Coast Air Quality Management District, California, outlined the full extent of national air quality violations on the health of the 13 million population in that region. Official figures call for around 80 per cent reduction in emissions in 2010, although new estimates may require 88 per cent reduction of reactive organic gases. Furthermore, ground-level ozone concentrations may be more pernicious than earlier suspected.

Fuel cells offer a new technology which could dramatically reduce nitrogen oxides emissions, in particular, and all pollutants in general. This applies to both stationary and mobile applications, although alternative fuelling of internal combustion engines, for example by methanol, might have short-term benefit. A new, low emission vehicleklean fuel programme is already influencing thinking in the automotive sector worldwide. Apart from implementation of the zero-emission vehicle policy, additional strategies, including hybrid propulsion systems, were being encouraged. Realistically, however, the politics and economics of oil supply and national debt were also driving the Legislators! Confidence in technological progress as well as public support, has led to an increased goal of 200,000 electric vehicles in the area by the year 2000, in place of the previous target of 40,000. Significantly, fuel cells as well as batteries qualdy as zero-emitting power sources, so that on-board reforming (for larger vehicles) would not be contentious. The immediate cost-benefits of greater efficiency and fuelling with renewable energy sources are not lost on the Administration.

Lloyd recommended that the large resources directed to advanced battery development should be extended towards fuel cell research and development. Great promise for electric vehicles in a cleaner future was foreseen.

Continuing to focus attention on Southern California, D. M. Moard of Southern California Gas Company (SocalGas), explained how they had engaged in co-operative programmes of

fuel cell research, design and development over a number of years with manufacturers, institu- tions and government departments. This will now lead to provision of a partial service based on PAFC capacity, fuelled by natural gas and ranging in capacity from a few kW, to multi- MW systems fitted with downstream thermal cycle plant. To date, cost had been a hindrance to commercial exploitation, but the break-even point was in sight for PAFC. In- deed, figures were produced to show that in certain selected high energy cost sites, fuel cell installations would bring immediate financial returns. Hopefully, similar trends would emerge for MCFC and SOFC from the

Thus, SoCalGas was presently installing 200 kW PAFC sets, manufactured by ONSI (a joint venture between I.F.C. and Toshiba to develop ON SIte energy generators), based on the I.F.C./U.T.C. design; a twenty-year life was optimistically predicted, with intermediate stack replacement. Being an on-site package, customers could expect to benefit from energy cost savings, while SoCalGas would benefit by progressing fuel cell introductions to the market. Following the initial order of 10 units for 1992, the Company is negotiating further orders in collaboration with local property developers and others.

Revitalising the whole “Hydrogen Economy” debate B. Rohland of Zentrum fur Sonnenenergie-und- Wasserstoff-Forschung , Stuttgart, surmised that hydrogen would play a significant role as a storage and transport fuel derived from renewable sources. Thus, in Ger- many, one scenario envisaged an increasing share of energy from renewables, being 13 per cent in 2005 up to 69 per cent in 2050, of which hydrogen would be 11 per cent in 2025, and 34 per cent in 2050. An inter-related electricity and gas market was proposed for a future clean energy system.

Fuel cells represented the most important option for efficient storage and interconversion of energy. Contrasting with one earlier prediction, Rohland considered that medium and high temperature fuel cells would operateat high

mid- 1990s.


efficiency and provide high-grade waste heat at competitive cost. Medium temperature units would prevail if pure (stored) hydrogen were used, and high temperature devices could ad- vantageously be deployed with biogas- hydrogen mixtures.

The final paper of the meeting, by T. Satomi of Tokyo G a s , encapsulated all of the excite- ment, drive and vision surrounding the prospect of fuel cell powered cities in the future. Being one of the few speakers to publicly acknowledge the inextricable interdependence of all aspects of social development, he related the activities of the Japanese Community Amenity Network (C.A.N.) towards integrated city construction. With a fuel cell at their heart, these units would redeploy by-product heat and fuel, and recycle all waste and water. He con- fidently predicted that, through innovation and mass production, PAFCs would achieve necessary cost and performance targets by 2000. At that time coal-gas fuelled, dispersed MCFC capacity of 1 MW and above could be expected to enter service; SOFC might follow for on-site applications sometime later provided durability could be improved.

Reiterating earlier projections, Satomi predicted a 30 per cent increase in energy demand for 2000, with electricity taking the major share. Coupled with increasing energy supply problems and environmental decay, a rational approach to future social needs had become imperative. Waste heat reuse, refuse recycling and water resources needed much more serious consideration than the ad hoc, short-term policies of previous generations.

The essential element of the C.A.N. proposal was integration, efficiency and recycling of the total energy and resource inventoq for a whole city, built on approximately 100 hectares, with nearby industrial complexes assimilating waste heat. Solar energy, biogas, heat-pumps and pond heat-stores were a few of the advanced technologies which could contribute. One design has 8,000 dwellings devouring 10 MW of electricity generated from fuel cells coupled to thermal cycle, steam plant, absorption chillers and heat pumps. With a PAFC unit,

overall efficiency could be 70 per cent represen- ting a 28-35 per cent saving in energy, 25 per cent saving in water and 30 per cent reduction in effluent.

Dramatic artists’ impressions of possible skyscraper cities up to 2000 metres high were shown; these would address land shortage problems. Natural gas was the fuel of choice, and fuel cells the power units. Infrastructure was three-dimensional. These would be “in- telligent” buildings with state-of-the-art control networks. Each one would require up to 100 MW of power; this would be supplied by zoned 5 MW fuel cells. Satomi considered a return to DC power supply for such autonomous cities. In combination with other DC devices such as computers, solar cells, etc., an ideal hybrid system could be designed. However, in discussion, it emerged that DC was not a viable solution due to switching com- plexities and bus-bar sizing/weight; new AC technologies were becoming available. Ultimately, Satomi hoped that hydrogen would displace natural gas as the cleanest fuel of all, leading to even cleaner and more efficient power generation. In conclusion, it was apparent that some Japanese philosophers are already formulating solutions to problems that the rest of the world prefers to ignore.

Discussion Professor Steele closed the proceedings with

a brief review. He highlighted the continuing progress being made towards fuel cell commercialisation. Despite this, greater technical efforts must accompany initiatives to secure the role of fuel cells in the market place, and additional commitment and investment was needed. Nevertheless, the Arthur D. Little report was encouraging and early air quality legislation should assist these commercial initiatives.

During the meeting formal and informal discussions took place, perhaps the most animated concerned the cost and performance of our favourite status symbol: the (electric?) car. The full proceedings of this Symposium will be published in a forthcoming issue of the Jouml of Power Sources.

Platinum Metals Rev., 1991, 35, (4) 22 1

Michael Faraday and Platinum “THIS BEAUTIFUL, MAGNIFICENT AND VALUABLE METAL”

I t is as an experimentalist in thefield of electricity and magnetism, that Faraday is best remembered, but his investigations were many and various. To mark the bicentenary of his birth several accounts of his life and work have already been published elsewhere, none the less it is in- structive to note just a few of his experiments that involved the platinum metals and to recall his long association with Johnson Matthey.

Michael Faraday, who was to become one of the greatest scientists of the nineteenth century, was born at Newington Butts on September 22nd, 1791. At that time Newington was a country village in the county of Surrey, but as London expanded to the south east its boundary spread far beyond Newington, which is situated south of the river Thames close to the well-known “Elephant and Castle” road junc- tion from which Newington Butts and five other thoroughfares radiate. After the family moved to the west end of London, Faraday began to earn money by delivering newspapers for Mr. G. Riebau, a French emigre, who sold books and had a bookbinding business. At the age of thirteen, Faraday was apprenticed to Riebau as a bookbinder and worked for him conscientiously for some seven years. Although he had received only a rudimentary education, Faraday took advantage of the opportunity which his apprenticeship provided and read widely, including some of the scientific books stocked for sale or brought to the shop for rebinding. He later wrote that he had been greatly impressed with Mrs. Marcet’s “Conver- sations in Chemistry” and the third edition of the “Encyclopaedia Britannica”, published in Edinburgh in 1797. Interestingly, the five page section on PLATINA in that edition concludes:

“As those motives which at first prepossessed the COUR of Spain against this metal no longer exist, it is to be hoped that the Spanish monarch will neither despise so rich a treasure as his mines of platina, nor refuse to the world the numerous advantages that may be derived from a substance that promises to be of so much importance in commerce and the arts.”

Faraday’s conduct had so impressed a Mr.

Dance, a customer of Riebau’s and a member of the Royal Institution of Great Britain (found- ed in 1799 for the encouragement of research and the application of science to the common purposes of life), that in the early part of 1812 he gave young Faraday tickets for the last four lectures delivered by the great chemist Hum- phry Davy at the Royal Institution, these being on February 29th, March 14th, and April the 8th and 10th; Davy being knighted by the Prince Regent on April 9th. Having taken notes during the lectures, Faraday “afterwards wrote them out more fairly in a quarto volume” and in December 1812 sent them to Davy, together with a request for employment. Early in the following year, when a laboratory assistant had to be sacked for brawling, Faraday was sum- monsed to the Royal Institution and on 1st March, 1813 he was engaged by Davy as his laboratory assistant for a weekly wage of 25 shillings. Later, Faraday was to be described as Davy’s greatest discovery!

In the autumn of that year, despite the con- tinuation of the Napoleonic war, Sir Humphry and Lady Davy went on a tour of the continent of Europe and Faraday accompanied them as an amanuensis. Thus, he visited many of the principal centres of learning and met many of the leading scientists of the day. He recorded in his journal the experiments he observed including “burning the diamond” by means of the sun’s heat concentrated through the great lens of the Grand Duke of Tuscany, at the Accademia del Cimento in Florence. During this experiment, on March 29th, 1814, the platinum supporting the diamond “was observed to fuse”.

On their return to England, Faraday was


Michael Faraday

An acute observer and brilliant experimenter, Faraday made many discoveries that contrihuted to the advancement of science and technology, and which are still important today. He obtained supplies of platinum for his investigation from Wollaston and from Percival Norton Johnson, and visited Hatton Garden from time to time, even suggesting that Members of the Royal In- stitution should “go into the workshops of Mr. Matthey, and see them hammering and welding away”. Elected a Member of the Royal Society in 1824, he was one of the many distinguished peo- ple who sponsored Johnson for election to that Society in April 1846

1 791 - 1867

Reproduced by courtesy of me Diveelor of me Roy.1 Indmtlon

re-engaged by the Royal Institution on May 15th, 1815, working under the guidance of Davy, who was to have a profound influence on Faraday’s scientific and intellectual development. It should be remembered that Davy, by his researches and his writings, made a significant contribution to the early history of platinum. Faraday soon began original researches, publishing his first paper in 1816.

Heterogeneous Catalysis In a paper read to the Royal Society on

January 23rd, 1817, Davy described the ac- cidental “discovery of a new and curious series of phenomena.” During his investigations of flames and combustibility (which led to the miners’ safety lamp) Davy arranged a fine platinum wire above the coal gas flame in a small wire-gauze safety lamp. When he introduced more coal gas, the flame went out but “that part of the platinum wire which had been hottest remained ignited, and continued so for many minutes.” He found that when a platinum or palladium wire was introduced into a mixture of coal gas and air the wire “immediately became ignited nearly to whiteness”.

Some years later, in 1823 Johann Wolfgang Dobereiner (1780-1849), Professor of Chemistry at Jena, developed a spongy platinum which catalysed the combination of hydrogen and oxygen at room temperature and

caused the platinum to become red hot. The information was quickly passed to Faraday, who had been assisting Davy with his experiments when this phenomenon of heterogeneous catalytic oxidation was discovered. Faraday repeated Dobereiner’s experiment, and having verified the result, announced “I think that every chemist will be glad to hear its nature.”

In the same year Faraday prepared a review of the work that had been carried out on the action of platinum on mixtures of oxygen, hydrogen and other gases, but it was 1834 before he returned to the subject of catalysis.

The Birth of Alloy Steels Faraday was the son of a north-country

blacksmith, so it was perhaps fitting that one of the early investigations he carried out at the Royal Institution was to establish the effects of adding to iron small amounts of alloying elements, including platinum, palladium, rhodium, iridium and osmium. The work was carried out in collaboration with James Stodan (1760-1823), a London cutler, with a view to


establishing whether alloys could be produced which would take a better cutting edge or which would be less susceptible to corrosion than the currently available materials. Their investigations began about 1819, with a first account reported to the Royal Institution in 1820 and a more substantial paper presented to the Royal Society in 1822. Their laborious metallurgical researches concerning the preparation and properties of alloys of steel during the years 1819 to 1824 have been thoroughly researched and documented by Sir Robert A. Hadfield, a metallurgist with fifty years of experience in the field of ferrous metallurgy, who in 1931 concluded “that Fara- day’s work was of real and lasting interest and value”, and that his work pointed the way to the future development of alloy steels.

As noted by Hadfield, aluminium, chromium, cobalt, manganese, nickel, silicon and tungsten, the elements later used in alloy steels, were very difficult to obtain in the period 1819 to 1824, while platinum and some of its associated metals were readily available from Dr. William Hyde Wollaston; although it must be remembered that ruthenium was not identified until 1844. Hadfield summarised the information from the 1820 and 1822 papers by Faraday and Stodart, noting that perfect alloys of platinum and steel were obtained over a wide range of compositions.

“From 1 to 3 per cent of platinum improves steel for edge instrument;. . . . Equal parts by weight form a beautiful alloy which takes a fine polish and does not tarnish; the colour is the finest im- aginable for a mirror; 90 of platinum with 20 of steel also gives a perfect alloy with no disposition to tarnish; 10 of platinum to 80 of steel forms an excellent alloy, but one which is quite unfit for mirrors owing to a fine damask.”

Wollaston provided rhodium for laboratory experiments and later for the manufacture of rhodium steel “in the large way.” It was found that rhodium combines with steel in all propor- tions, but although these alloys were regarded as “perhaps the most valuable of all . . .” it was realised that the scarcity of rhodium would prevent them becoming of general use.

Entries in the Royal Society paper of 1822

suggest that ternary alloys of steel, iridium and osmium were investigated, but once again the scarcity of the metals was recognised as a deter- rent to the general use of these alloys. At that time palladium was in short supply, but even so a 1 per cent addition of palladium to steel was valued for making instruments that required a perfectly smooth edge.

Following the death of Stodart on September l l th, 1823, Faraday appears to have devoted less time to work on steel alloys, although from the notes in his diary it is clear that he continued the work at least until the summer of 1824. In the same year the Sheffield firm, Green Pickslay & Co., having experimented with the alloys recommended by Faraday, sent him a steel specimen alloyed with silver, iridium and rhodium . . . “furnished by Mr. Johnson, No 79 Hatton Garden”.

The Preparation of Optical Glass In the second half of the 18th century British

astronomers were able to purchase domestically produced achromatic telescopes incorporating the best optics then available, but in the first quarter of the next century technological supremacy was perceived to be passing to con- tinental Europe and it was believed that leader- ship in observational astronomy would follow. In an attempt to counter this situation the British government funded, through the Royal Society, a programme to investigate the manufacture of the optical glass from which achromatic lenses were produced, and Faraday was one of those charged with this task. Initial experiments were conducted at the Falcon Glass Works of Apsley Pellat and James Green in Southwark, but in 1827 the work was transferred to the Royal Institution.

The investigations carried out by Faraday and his faithful assistant, Sergeant Anderson of the Royal Artillery, lasted some four years, the results being reported to the Royal Society in the 1829 Bakerian lecture, and published in 1830. As well as formulating a new glass, Fara- day pioneered the use of platinum for the vessels, stirrers and ladles which came into contact with the molten glass, and also added fine


platinum powder to the melt to eliminate gas bubbles which otherwise flawed the product.

Beginnings of Electrochemistry The idea that in some way electricity was

responsible for chemical attraction, and should therefore be able to overcome it, was formulated by Davy. He successfully demonstrated this in 1807 when he isolated potassium, using the current from a powerful battery to decompose solid caustic potash arranged on a platinum spoon and contacted with a platinum wire. A few days later he similarly liberated a second new element, sodium, by the decomposition of caustic soda. In 1832 Faraday followed up Davy’s work with a series of studies on electrochemical decomposition, using platinum for the electrodes so that they “shall not be acted upon by the elements to be evolved.” His investigations led to the formulation of his two laws of electrolysis and also to the introduction of the terms st i l l used today in electrochemistry. He consulted William Whewell (1794-1866), later Master of Trinity College, Cambridge, about terminology, who wrote to Faraday in a letter dated May 6th, 1834 “I still think anode and cathode the best terms beyond comparison for the two electrodes”; the first use of these words in Fara- day’s diary occurring on May 13th.

The electrochemical properties of the platinum metals continue to attract wide interest. Indeed, in view of the title and content of the conference reported by D. G. Lovering in this issue of Platinum Metals Review, it is perhaps worth recording that on October 22nd, 1842, William R. Gmve wrote a private letter to Faraday in which he described the use of platinised platinum electrodes in the first practical fuel cell. The following week Grove com- municated his invention to the editor of The Philosophical Magazine.

Magnetism and Diamagnetism The last major piece of research carried out

by Faraday involved a study of the magnetic properties of many materials, including the platinum metals, and led to the discovery of

diamagnetism, a term decided upon after further consultation with Whewell. On November 4th, 1845 Faraday was using a new horse shoe electromagnet, the compound coils around each leg of the magnet consisting of some 520 feet of copper wke. A bar of heavy glass was suspended between the poles of the magnet by a silk thread, and when the poles were activated by the application of an electric current through the coils the glass bar changed its position, taking up an equatorial position. “How well this shews the new Magnetic property of matter” wrote Faraday. He experimented with a very wide variety of materials and found that all li- quids and solids were either attracted to, or repelled by, a magnet, if the magnet was powerful enough. He examined many samples of platinum metals and compounds obtained from Johnson, and among the many items recorded in his diary it was noted that palladium wire and foil from Johnson “were clearly magnetic” while palladium chloride was not. During the year Faraday also discovered the

phenomenon that later came to be known as the “Faraday Effect”, the ability of a normally isotropic transparent substance to rotate the plane of polarisation of light when subjected to a magnetic field. This was the foundation of magneto-optics, on-going studies of which indicate that platinum has great potential for use in magneto-optic data storage systems.

Faraday’s Diary Mention has been made previously to dated

entries in Faraday’s diary, which was in fact his handwritten record of the various experimental investigations he made from September 1820 to the early part of 1862. An edited version of his manuscript was published in 1936 and provides a fascinating insight to his many scientific activities, giving details of his procedures, successes and failures, many of which did not appear in the formal papers that reported the results of some of his major investigations. From the diary it is possible to obtain an indica- tion of his wide involvement with the platinum metals, either as the subject of one of his investigations or as a component of some piece of


apparatus. Two interesting instances of his use of platinum are given below.

The Concept of Power from Magnetohydrodynamic Generation

Following his discovery of electromagnetic induction in August 1831 , which is regarded by many as his most noteworthy contribution to science, on January 12th, 1832, Faraday was conducting electrical experiments in the river Thames, from Waterloo Bridge “by !eave of Mr Bridell the Secy.” Two clean bright copper plates, 2 feet by 1 foot, were suspended in the river by thick copper wires, one at the toll house on the north side of the river, and the other at the sixth pier. The latter was fastened to an horizontal copper wire running along the parapet of the bridge, and as the ends of the two wires were connected by cups of mercury with the ends of a galvanometer wire “the whole became one wire from plate to plate; and the circuit was completed by the water between the plates, which being in motion up or down, was expected to produce, by magneto-electric induction, currents rendered sensible at the galvanometer.” Faraday noted that evidence of an electrical current was soon obtained.

He returned the next day to continue his experiments and to consider whether any source of electricity could exist in the river, other than magneto-electric induction. On this occasion two platinum plates about 10 inches square were lowered into the river, one from the second and the other from the seventh pier of the bridge, placing them about 700 feet apart. When the circuit was completed the galvanometer indicated that “there was plenty of electricity” both when the platinum plates were kept under the water by means of iron weights attached to them by ropes and when the plates were allowed to float on the surface.

Although both plates had been cleaned prior to the experiments they became somewhat tarnish- ed, one being discoloured by red oxide of iron, due to earlier furnace experiments on glass.

Faraday had in fact demonstrated that when an electrically conductive liquid, in this case the water in the Thames, flows through a magnetic

field (here, the earth’s magnetic field) electromagnetic induction occurs. This is the principle behind the operation of magnetohydrodynamic generators, which offer an opportunity to produce electricity efficiently and with lower environmental pollution than conventional fossil fuelled power stations.

A Platinum Light During July and August 1857 when in-

vestigating the performance of various galvanometers, Faraday required a light source “as narrow as possible to cause its sudden appearance and disappearance in the mirror.” One of the sources he tried was a platinum wire 1 inch long and 1420 of an inch thick ignited to just below the fusing point by the electric current from two pairs of Grove’s plates, the circuit requiring the insertion of 34 inches of 1/64 inch diameter copper wire to prevent the platinum melting. Although this gave a very bright light, Faraday initially concluded that a platinum wire light would not do, the task requiring “either the lime light or the Electric light.” Lime light was more diffuse than the platinum light, however, and he later employed both sources, even making a copper variable resistance to regulate the electric current passing through the platinum wire.

The Platinum Lecture Faraday was one of the great popularisers of

nineteenth century science, striving to interest politicians and educationalists in the need to advance science teaching. The Friday Evening Discourses which he started at the Royal In- stitution in 1826 remain to this day an important channel of communication between leading scientists and the general public. At one of these, on Friday February 22nd, 1861, towards the end of his active life, he delivered his famous “Lecture on Platinum.”. Drawing upon his vast knowledge of platinum “this beautiful, magnificent, and valuable metal;” he demonstrated many of its remarkable properties and spoke also of some of the other five platiniferous metals. Having acknowledged that Dr. Wollaston had been mainly responsible


for making platinum available until that time, Faraday then went on to describe the process developed by “my friend Deville” and which had “been adopted by Messrs. Johnson and Matthey, to whose great kindness I am in- debted for these ingots”. In fact, Faraday had not planned to deliver this lecture; he had intended that Henri Sainte-Claire Deville would come from France and demonstrate the fusion of some thirty or forty pounds of platinum before the assembled members. In 1857 Deville and Jules Debray had devised the lime-block furnace fired by a mixture of oxygen and coal gas in which it was possible, for the fvst time, to melt platinum on a large scale. In August of that year the English rights to the patented process had been acquired by Johnson Matthey and before accepting the invitation to demonstrate the process to the Royal Institu- tion, Deville consulted George Matthey who, on February 5th, advised that there were stil l many practical difficulties to be overcome, and that he would not welcome the process being exhibited. It seems that Matthey was charged with passing Deville’s decision to Faraday, for on 21st February he wrote to Deville that “Dr Faraday has behaved most kindly and did not appear in the least annoyed when I gave him your letter.” It would appear that Faraday wished to see the problems for himself, for on Wednesday, February 13th, W. J. Cock, a former partner in the Hatton Garden fm, recorded in his diary “Tried fusion of platinum with GM . . . Dr. Faraday was present.” The entry is reproduced above. In fact it was the

end of May before this process was successfully employed by Johnson Matthey.

Another Imperfect Account In the space available it has only been possi-

ble to present a limited and very selective account of Famday’s work with the platinum metals. During his investigations he established some of their electrochemical and magnetic properties, made use of them on a laboratory scale and indicated possible new industrial uses. Additionally he took a personal interest in the development of the use of the lime furnace, which enabled platinum to be melted commercially on a large scale for the first time. Apologising to the Members of the Royal In- stitution for being unable to have the process demonstrated to them, he referred to his lecture on platinum as “this imperfect account”. Despite his failing health and the short time available for its preparation, it became a classic, disseminating a knowledge of the platinum metals to a wider audience. It was published in 1865, being bound with “The Chemical History of a Candle”, which is probably the most famous series of Christmas lectures given for children by Faraday at the Royal Institu- tion; another of his innovations in scientific communication which flourishes to this day.

Acknowledgements The information in this account has been gathered

from numerous sources, especially papers published previously in this journal, the relevant section of “A History of Platinum and its Allied Metals”, and the references therein. I.E.C.


ABSTRACTS of current literature on the platinum metals and their alloys

PROPERTIES Effects of Sputter Gas Medium on the Nanometer-Scale Surface Structures of the Pt/Co Multilayers

Appl. Phys. Lett., 1991, 59, (3), 289-291 The use of scanning tunnelling microscopy has enabled near atomic resolution images of the surface structure of polycrystalline Pt/G multilayer thin films to be obtained. Surface relief structure was dependent on the sputter gas; Ar-sputtered films consisted of narrow, essentially flat terraces separated by monatomic steps while on Xe-sputtered f h s the step heights were close to the bilayer thickness, the difference being attributed to the energy distribution of the reflected sputter-gas neutrals that bombard the growing film. Surface structures were related to the magnetic coercivities of the films.

Reduced Hydrogen Embrittlement Susceptibility in Platinum Implanted High Strength Steel

KOSIK, Nucl. Insmm. Method Phys. Res., 1991,

Pt was implanted into high strength electroslag remelted (ESR) 4340 steel samples to a dose of 1OI6 atoms/cm* . The samples implanted with Pt showed less diffusible H and were also able to sustain signifkantly higher loads before fracture than the unimplanted steel. SEM verified the presence of brittle cracking typical of H embrittlement type failures. Degradation of mechanical properties due to H embrittlement was thus significantly reduced.

In situ Electrochemical Scanning Tunnel- ing Microscopy of Single-Crystal Surfaces of Pt(l11), Rh(l l l ) , and Pd(l l1) in Aqueous Sulfuric Acid Solution

Technol. B , 1991, 9, (2), 457-464 Electrochemical scanning tunnelling microscopy was applied to single crystal Pt( 11 l), Rh( 11 1) and Pd( 11 1) surfaces in aqueous H,SO,. Atomically flat Pt(ll1) surfaces became roughened in solution by the oxidation-reduction cycle. A single potential cycle causes the formation of many adatoms and very smal l clusters on the Pt(l11) terrace. A steady state surface structure is seen after a few potential cycles. The STM image has regularly arrayed islands whose diameter and height are in the ranges 2-3 and 0.5-0.75 nm, respectively. Flame annealing can be successfully applied for Rh and Pd electrodes. Atomically flat terrace-step structures can be seen on Rh( 11 1) and Pd( 11 1) surfaces.

S. L. TANG, P. F. CARCIA, A. J. McGHIE and E. B. JAMES,

J. G. COWIE, L. J. L O W E R , R. 1. CULBERTSON and W. E.

B59/60, (Part II), 871-874

K. SASHIKATA, N. FURUYA and K. ITAYA, 3. vac. sci.

Investigation of FZ-Silicon Doped with Pt J. PROKES, Phys. Status Solidi A, 1991, 125, 263-272 Measurements were performed on n-Si crystals grown by the floating zone method and doped by diffusion with Pt. The parameters and distribution profiles of shallow and deep levels were investigated by capacitance methods. The levels at E, -0.23 eV and E, +0.33 eV were attributed to Pt, whereas those ly- ing at E, -0.32 eV and E, -0.44 eV were probably not directly connected with Pt.

Paramagnetic Susceptibility of Quasibinary Pt Mn-Pt Fe Solid Solutions

Fiz. Metal. Metalloved., 1991, ( S ) , 58-62 Studies of the paramagnetic susceptibility of Pt,MqFe,, in atomically ordered (300 < T < 800 K) and disordered (800 < T < 1200 K) states were performed. The concentration dependence of the paramagnetic state on the Curie temperature during transition from the ferromagnetic alloy Pt,Mn to antiferromagnetic Pt,Fe proceeded according to the Heizenberg model registered in two co-ordination spheres. The effect of a decrease in effective magnetic moment during atomic ordering and during transition into the antiferromagnetic state was discussed.

Formation of the PtMnSb Phase in Thin Multilayered PtlMnlSb Films

Muter. Trans. JIM, 1991, 32, (2), 195-198 Thin multilayered f h of rPt(1.2 nm)/Mn(l.2 nm)/Sb(2.6 nm)I and Pt(l.0 nm)/Mn(2.0 nm)/ Sb(2.0 nm)l were prepared on glass substrates by an ion-beam sputtering method, and the formation of the Clb-PtMnSb phase in the as-deposited films was studied by XRD and TEM. The multilayered samples produced at mom temperatue consisted of a layered structure of amorphous or nano-crystalline phases. However, as the substrate temperature increased up to - 473 K, inter-layer mixing among the constituent multilayers was found to occur and the PtMnSb phase was formed.

The Effect of Sintering Temperature on the Barrier Height of pType PtSi Schot- tky Diodes

N. I KOUROV, I. I. PIRATINSKAYA and W. N. TSIOVKIN,

N. HAYASHI, K. MORII, T. MATSUI and Y. NAKAYAMA,

V. W. L. CHIN, S. M. NEWBERY, J. W. V. STOREY and U. THEDEN, AUSt. 3. Phys., 1991, 44, (I), 67-72 The barrier heights of p-type <loo> PtSi Schottky diodes prepared by sintering the samples at two different temperatures were studied using electrical forward I-V and IR photoresponse techniques. The results showed that there was a consistent difference of - 0.06 eV for two samples sintered at different temperatures.


Ordering and Magnetic Hyperfine Fields in Pt3Mno,9Fe,., Studied by Mossbauer Spectroscopy K. SZYMANSKI, L. DOBRZYNSKI, E. GERKEMA and A. M. VAN DER KRAAN, 3. Phys. COdnS. Matter., 1991, 3, (29), 5469-5478 The effect of structural defects on the magnetic properties of Pt,Mn,,,Fe,,, was studied. The magnetic hyperfine field distribution showed an in- homogeneous magnetisation distribution in the samples. The cold work gave a number of anti- phase boundaries dividing the sample into subvolumes with the linear dimensions of 30-100 A. The magnetisation of these subvolumes performed a superparamagnetic-like relaxation.

Effect of Pt Addition on Melt-Processed YBaCuO Superconductors

MIYAMOTO and K SAWANO, 3pn. 3. Appl. Phys., Pan 11 Lett., 1991, 30, (SA), L813-L815 A fine dispersion of Y , BaCuO, (2 11) inclusions - 1 pn in size has been obtained in YBa2Cu,0, matrix by the addition of Pt, as PtO,, to the precursor. Pt is considered to act as nucleation sites during the formation of 2 11 from Y ,O , and liquid phase Ba-Cu oxide. The sample containing added Pt displayed a critical current density > 2 x 10' A/an2 at 77 K and 1 T, as high as that of quench and melt growth processed material.

Palladium Clusters on Mica: A Study by Scanning Force Microscopy

Technol. B, 1991, 9, (2), 794-797 The study of clusters attached to surfaces is of interest because of their application to catalysis and their intermediate state between bulk and single atoms. A scanning force microscope equipped to measure topography and the friction force between sample surface and the tip has been used to study Pd clusters on cleaved faces of single crystal mica. The shape of clusters in the 50 nm range was found to be triangular with truncated edges.

Compound Formation at the Interaction of Pd with Strained Layers of Si,,Ge, Epitaxially Grown on Si(lO0)

FLER, Appl. Phys. Lett., 1991, 59, (6), 665-667 The interaction of thin Pd films deposited on strained layers of Si,,Ge, epitaxially grown on Si(100) has been studied. ?he Ge concentmion in the molecular beam epitaxy grown films of Si,,Ge, was x=0.16, and their thickness was 2300 A. A highly textured ternary compound (Pd, Si,,GeJ fonned concurrent- ly with the PdGe phase, at annealing temperatures between 200 and 55OOC. Above 500OC a region of Si,,Ge, alloy with high Ge concentration formed between the fully reacted compound and the unreacted Si , layer.

M. MORITA, M. TANAKA, S. TAKEBAYASHI, K. KIMURA, K.

J. COLCHERO, 0. MARTI and J. MLYNEK, y. VaC. SCi.

A. BUXBAUM, M. EIZENBERG, A. RAIZMAN and F. SCHAF-

The Effect of High Pressure upon the Valence Transition in EuPd Si

LEONARD, 3. Phys. condens. Matter, 1991, 3, (29),

The so-called valence transition in EuPd,Si, which was observed using energy-dispersive synchrotron X- ray powder diffraction at elevated pressures was centred at 8 kbar. The estimated increase in valence at the transition was 0.2 and was associated with crossover of 4f and 6d/s bands. It is concluded that both pressure and temperature changes induce same valence transition in the alloy.

Structural Analysis of a Novel Carbon Stabilized Mg-Pd Alloy: Mg,PdC,

Common Met., 1991, 169, (2), 369-373 The novel crystalline Mg-Pd alloy, Mg,Pdq, was initially isolated through dehydrogenation of an amorphous hydride, Mg,PdqH,, which was prepared by solution techniques; but now it can also be obtained by heating Mg and Pd metals in the presence of graphite. Although the C atom position could not be refined, samples prepared by high temperature techniques indicated that the C content, x, could be as low as x = 0.1.

Low-Frequency Internal Friction of Pd,oNi,oP20 Near the Glass Transition H.-R. SINNING, Acra Metall. Mater., 1991, 39, ( 5 ) ,

The internal friction of amorphous Pd,Ni,P, near the glass transition was studied at oscillation frequen- cies of - 0.1 Hz. The glass transition manifested itself by a characteristic increase of viscoelastic damp- ing measured at 550-600 K. Above 575 K, the metastable equilibrium value of internal friction obeys an Arrhenius equation with an apparent activation energy of 2.77 eV. An apparent acceleration of the relaxation kinetics due to a pre-annealing treatment to past the glass transition is not understood.

Atomic Structure of the Crystalline/Amorphous Interface in a Directionally Crystallized Pdso Si,, Alloy W. H. BREARLEY, P.-C. SHIEH and I. M. HOWE, Metall. Trans. A , 1991, 22, (6), 1287-1298 An amorphous ribbon of Pd,Si, alloy was directionally crystallised under an imposed temperature gradient of 25 Wmm and a growth rate of 0.0785 d s ; and the surface structure of the crystalline/amorphous interface was studied. The amorphous Pd,Si, crystallised into a broken- lamellar eutectic of Pd,Si and Pd,Si, equilibrium phases. The Pd,Si phase is faceted and grows by the nucleation and propagation of ledges on the (010) planes, while the Pd,Si, phase is largely coherent with the Pd,Si phase. The directional crystallisation apparatus that was developed can produce crystalline/amorphous interfaces, under carefully controlled conditions, which are suitable for TEM.

D. M. ADAMS, A. E. HEATH, H. JHANS, A. NORMAN and S.

5465-5468

D. N O a U S , B. BOGDANOVIC and U. WILCZOK, 3. Less-

85 1-858


Early and Late Mechanical Alloying Stages of the Pd-Si System

PARADISO and G. ENNAS, 3. Muter. sci., 1991, 26,

Four Pd-Sicompositions (Pd:Si = 2 5 1 ; 3:l; 4:l and 5:l) were mechanically alloyed by ball-milling. The first step of the milling process consisted of a very fine fragmentation of the Si particles into the Pd matrix, followed by the formation of the intermetallic line compound Pd,Si which could occur for the 2.5:1, 3:l and 4:l compositions. Long milling times, up to 56 h, promoted a demixing process towards the parent elements for the 2.5:l and 4:l compositions.

Electromigration and Diffusion of Hydrogen in Amorphous Alloys of Pd 8 2 Si ,*-Type

Muter. Sci. Len., 1991, 10, (8), 455-458 The direction of electromigration and the values of the effective valency of H in amorphous alloys Pd Si H,, were investigated for different H concentrations and for alloys Pd,,,Ni,Si,,H, at 368 K, in order to assess the value of PdSi alloys as radiation shields. It was found that H migrates in amorphous alloys in the direction of the external electric field. The effective H valency in amorphous alloy Pd Si increases simultaneously with the increase in H concentration, and the chemical diffusion coefficient increases with the increase in H concentration. In Pd,,Si,, substitution of Pd with Ni results in a decrease in the value of the chemical diffusion coefficient and effective valency.

Properties of Conductive Films Made from Fine Spherical Silver-Palladium Alloy Particles

M. MAGINI, N. BURGIO, S. MARTELLI, F. PADELLA, E.

(14), 3969-3976

R. PIETRZAK, R SZATANIK and B. ROZENFELD, 3.

K. NAGASHIMA, T. HIMEDAand A. KATO, 3. Muter. SCi., 1991, 26, (6), 2477-2482 Ag-Pd alloy films 2-3pm thick were made by a thick- film technique using Ag-15 mol% Pd and Ag-30 mol% Pd alloy powders and mixtures of Pd and Ag powders prepared by the spray-pyrolysis method. The alloy particles sintered uniformly on firing, whereas the metal particles had uneven particle growth and large voids were formed in the fired films. Alloy films had better conductive properties and their resistivities were close to the intrinsic values for Ag- Pd alloys. Pd oxidation during heating in air was suppressed in the powde- at Pd content < 30 mol%.

Enrichment of Deuterium with Tritium in the Presence of a Palladium-561 Giant Cluster

1. MOISEEV, 3. Mol. catal., 1991, 66, (l), 99-104 A giant cluster of Pd,, Phen,(OAc) IM idealised formula was contacted with gaseous deuterium at room temperature and atmospheric pressure. The content of T in D was increased after contact at room temperature and atmospheric pressure for 5-10 days.

D. I. KOCHUBEY, V. P. BABENKO, M. N. VARGAFnKand I.

Ultrathin Films of Rh on Au{001} and Rh on Ag{001}: Growth Mode and Magnetism

Phys. Rev. B, 1991, 44, (3), 1438-1441 Deposition of minute amounts of Rh on a clean and reconstructed Au{001} surface destroyed the reconstruction and yielded a 1 x 1 structure. Deposi- tion of Rh on a clean Ag(OO1) surface produced overlayers which were partially covered by or intermixed with Ag, but which were pseudomorphic with the AgtOOl} substrate. Photoemission experiments in the very early stages of overlayer growth revealed a 4.120.3 eV splitting of the 4s levels of Rh, which was not observed in thick Rh films.

The High-Temperature Work Function Behavior of Polycrystalline Osmium R. N. WALL and D. L. JACOBSON, Metall. Trans. A,

Studies of the thermionic emission behaviour of randomly oriented polycrystalline 0 s showed its low thermionic work function of 4.68 eV at 1800 K which increased rapidly to 5.21 eV at 2600 K. The high temperatures and low pressures of these tests were designed to minimise any residual gas interactions with the sample surface. An allotropic phase transformation may explain the varying work function.

Interface Structure and Misfit Dieloca- tions in Thin Cu Films on Ru(0001) G. 0. POTSCHKEand R. J. BEHM, Phys. Rev. B, 1991,

Scanning tunnelling microscopy measurements showed that the strain at the interface between Cu films and a Ru(OOO1) substrate was reduced by a structural transformation from a more tightly bound, strained pseudomorphic first Cu layer to a unidirectionally contracted second Cu layer with periodic partial misfit dislocations. These results for a two- dimensional structure confirm the mechanism of stress accommodation in strain layers predicted in the dislocation model of Frank and Van der Merwe.

Site of Ruthenium in Icosahedral Al- Mn-Ru-Si Y. SAKURAI, Y. TANAKA, Y. WATANABE, s. NANAO, n. KAWATA and M. ANDO, Muter. sci. Eng., 1991, AIM,

The sites occupied by Ru atoms in Al,,Mn,,Ru,Si, and AI,Mn,Ru,Si, icosahedral alloys were investigated by the anomalous X-ray scattering technique with synchrotron radiation. Assuming that Ru atoms occupy Al or Mn sites in the atomic structure model (quasiperiodic configuration of icosahedral clusters) of the AI-Mn icosahedral phase, it is concluded that Ru atoms are preferentially substituted at Mn sites, which almost correspond to the vertices of the three dimensional Penrose tiling in i- Al,,Mn,,Ru,Si,. For i-Al,,Mn,Ru,Si, Ru atoms are substituted at the Mn site and at the site of Al atoms at the innermost shell of the model icosahedra.

H. LI, S. C. W, D. TIAN, Y. S. L!, J. QUINN and F. JONA,

1991, 22, (7), 1609-1613

44, (3), 1442-1445

896-899


Changes in the Electrical Resistivity of Fe-C/AI, 0 me-Ru Multilayered Films Due to a Magnetic Field R. NAKATANI and M. KITADA, 3. Muter. sci., Lett.,

Studies of the Fe-2.0 at.% C/AI,O,/Fe-1.7 at.% Ru junctions for obtaining a high relative resistivity change showed that the relative resistivity changes were between 0.2 and 1.0% in the prepared tunnelling junctions. The electrical resistivity change was caused by the tunnelling between two ferromagnetic layers. The area of the applied field, where the electrical resistivity was high, was broader than the area of the applied field where the magnetisation directions were thought to be antiparallel from the magnetisation curve.

1991, 10, (14), 827-828

CHEMICAL COMPOUNDS Platinum Complex Structure and Regularities of Trans-Effect Y. VAN and Y. HAN, Vestn. Mosk. Univ., Ser. Khim.,

Structures of Pt(1I) complexes of the types cis-[PtC12(PPh,) 1 and trans-[Pt(H)X(PPh ,) , 1 where X is Cl, Br or I, were studied by various NMR and spectroscopic techniques. The results showed the order of trans-effect ligands for Pt(I1) complexes: H > H,C=CH,> PMe, > PPh, > I > Br > Cl> NH,.

Novel Platinum(1I)-Diaminobiotin Com- plexes. Their Synthesis and Characterisation A. F. NOELS, N. NIHANT and A. J. HUBERT, Bull. SOL. Chim. Belg., 1991, 100, (7), 497-502 The diaminobiotin ligand (cis-3,4-diamino-2- tetrahydrothiophene valeric acid) was reacted with K chloroplatinate and with a diaquodiammine Pt(I1) cation. The reaction yielded new Pt complexes which were co-ordinated in a bidentate fashion through the diamine function of the ligand and had tPtN,CI,l and tPtN,l geometries, respectively.

Metallation of a Crown Thioether Ligand. Synthesis, Structure and Reactivity of [Pt(L')I[BF,l and Structure of [ PtI (L ')I [ BF I (L I = 2,6,1O-Trithia[ 1 1 I - rn-benzenophane) G. s. HANAN, J. E. IUCKHAM and s. J. LOEB, 3. Chem. SOL., Chem. Commun., 1991, (13), 893-895 The fmt example of a metallated crown thioether and a rare example of a macrocyclic complex containing a direct M-C bond is reported. The formation of square-planar crown thioether complex [Pt(L')I[BF,I occurs by the metallation of L ' ; and the versatility of this S,C donor ligand is demonstrated by substitution for the central S donor and oxidative-addition to octahedral complexes of PtIV. Complexes of L1 with Rh', Rut' and I f have the potential for exhibiting catalytic chemistry employing a thioether macrocycle.

1991, 32, (3), 302-305

Effects of Perturbed Symmetry: Low- Melting Stable Mesogens Based on ortho- Palladated Imines

Angew. Chem. Int. Ed. Engl., 1991,30, (6), 711-712 The symmetry of the ligand sphere was lowered in a dinuclear metallomesogen by replacement of PdCl aomethine by acetyl acetonate with formation of a mononuclear complex. The temperature range in which the mesophase existed was thereby reduced by

Metal Complexes of Benzodiazepines. Part 2. The Reaction of 1 ,CBenzodiazepines with Halide- Bridged Complexes of Palladium(I1) [Pd2X4(PPrmJ)21 (X = C1 or I)

and s. TOMMASINI, 3. Chem. soc., Dalton Trans.,

1 ,4-Benzodiazepines cleaved the halide-bridged complexes [Pd,X,(PPr",),l (X = C1 or I) to yield monomeric complexes where the benzodiazepine is co-ordinated through N(4) of the heterocyclic ring. The reactions between the Pd complex containing I and five 1 ,4-benzodiazepines were studied kinetically and thermodynamically in CHCl , . The stability of the monomeric complexes formed varied consider- ably and is attributed mainly to the difference in the rate constants corresponding to the reverse reaction.

Synthesis and Characterization of Palladium(I1) Complexes Derived from Aromatic Thiosemicarbazide Derivatives M. M. BEKHEIT, Y. A. ELEWADY, F. I . TAHA and s. I . MOSTAFA, Bull. soc. Chim. Fr., 1991, 128, (2),

The reaction of aromatic thiosemicarbazides with Pd(I1) yielded three types of Pd complexes with the compositions PdLCl,, Pd(L-H), and Pd(L-2H), where L are aromatic thiosemicarbazides. The IR spectroscopic data showed that the aromatic thiosemicarbazides behaved as neutral, mononegative and binegative ligands and co-ordinate in a bidentate or bridging tetradentate way.

Aspects of g2 Binding by Osmium- ammines H. TAUBE, pure Appl. Chem., 1991, 63, (s), 651-664 The chemistry of osmiumammines is examined. The strong tendency of Os(II), when the auxiliary ligands are saturated, for back-bonding interactions accounts in large part for the stability of a large number of new organometallic species. In most cases, the one- electron oxidation of the Os(I1) complexes takes place at potentials of < 1 V, and the resultant species have enough kinetic stability to be characterised. Because of the different requirements of Os(II), with its tendency for electron donation to p acids, and Os(III), which acts mainly as a s acceptor, the oxidation is often accompanied by dramatic changes.

M. J. BAENA, P. ESPINET, M. B. ROS and J. L. SERRANO,

around 100 K to 80-130OC.

M. CUSUMANO, A. GIANNETTO, P. FICARRA, R. FICARRA

1991, (6), 1581-1584

178-183


A Stable 0s’ 16-Electron Complex: Syn- thesisandStructureof[OsCl(NO)(PiPr,), 1

Chem. Znt. Ed. Engl., 1991, 30, (9 , 596-598 The 0 s complex [OsCl(NO)(PiPr,),] which is the first structurally characterised [OsL,l complex (L = monodentate ligand) was synthesised. Its reactivity toward Lewis acids and Lewis bases makes it a valuable building block in the synthesis of Oso and 0s” complexes.

Proof of Strong S-H ... S Bridges in [Ru(S H ,)(PPh 3)( ‘S ’)I .THF, the First H S Complex Characterized by X-Ray Crystallography

A n g m . Chem. Int. Ed. Engl., 1991,30, (5), 552-553 The H2S complex [Ru(SH,)(PPh,)(’S,’)I (1) which was obtained from [Ru(PPh,)(‘S, ’) precipitated as (l).THF on recrystallisation from H, S-saturated THF as yellow-orange crystals. X-ray structural analysis was performed on the Ru complex (l).THF. The H,S ligand in the (l).THF complex was found to be stabilised by strong S-H ... S bridges. On exposure to air the Rh complex was rapidly oxidised.

H. WERNER, A. MICHENFELDERand M. SCHULZ, Angew.

D. SELLMAN, P. LECHNER, F. KNOCH and M. MOLL,

Electrocatalytic Activity of a Graphite- Based Pt Electrode Modified with Metal Oxides towards Methanol Oxidation

Chem. Interfacial Electrochem., 1991, 305, (2),

The electro-oxidation of CH , OH was carried out on oxide-modified Pt electrodes using graphite as the substrate in 0.5 M H,SO,. A more negative zero- current potential ( - 70 mV vs. RHE) was achieved on a graphite-based Pt electrode modified with In + Pb mixed oxide and Au as compared with - 400 mV on an ordinary Sn-modified Pt electrode. However, the oxidation current did not increase rapidly with the electrode potential and the oxides were not sufficiently stable in the solution of 0.5 M HI SO,.

On the Electrocatalytic Activity of Platinum Catalysts on Carbon Carriers

Elektrokhimiya, 1991, 27, (3, 563-570 Studies of electrochemical activity of Pt/C catalysts containing various structural supports were performed during ionisation reaction and separation of H from the model electrode. The results showed that the swcific activity of Pt/C catalysts during oxidation

P. C. BISWAS, T. OHMOIU and M. ENYO, 3. Electroanal.

205-215

V. S. GATOTSKII, G. V. SHTEINBERG and N. A. URISSON,

of H, was highe; on non-porous suppo& than on highly porous supports even when the specific surface of Pt on highly porous supports was 3-4 times higher than on non-porous suppon.

ELECTROCHEMISTRY Electrooxidation of Dissolved co on a Platinum Electrode Covered with a Monolayer of the Chemisorbed CO Formerly Considered to be a Poison C. GUTIBRREZ and J. A. CARAM, 3. Electroanal. Chem. Interfacial Electrochem., 1991, 308, 321-325 Studies showed that under certain conditions, CO electro-oxidation took place on Pt at 0.6 V and in the presence of a full monolayer of adsorbed CO ‘poison’. A smooth Pt electrode held at a potential lower than 0.22 V, placed in an electolytic cell in which CO was bubbled for 1 h, showed in a subsequent voltam- mogram, under quiescent conditions two anodic peaks whose simultaneous existence was considered to be imposssible. One of them was the well known peak of chemisorbed CO at 0.94 V, which up to the present was considered to be a poison for the oxidation of dissolved CO.

Electrocatalytic Effect of Phenanthroline Iron Complexes on Oxygen Reduction in Sulfuric Acid Media L. GALICIA, I. GONZALEZ and Y. MEAS, React. Kinet. Catal. Lett., 1991, 44, (l), 109-114 A study of 0, reduction on a Pt rotating disk in 1 M H2S0, at different pHs showed an increase in the reaction velocity on addition of 2 x lo-’ M Fe(I1) and 0.1 M 1,lO-phenanthroline. The increase depended on the pH of the solution; at pH < 0.5 it was - 100 fold while at pH > 0.5 it was greater by a factor of 600. The change at pH = 0.5 was explained by a change in the co-ordination sphere of electrogenerated Fe(I1).

In Situ Infrared Studies of Glucose Ox- idation on Platinum in an Alkaline Medium

troanal. Chem. Interfacial Electrochem., 1991, 309, (1 and 2), 131-145 The oxidation of a-D( +)-glucose on a Pt electrode in 0.1 M NaOH was studied by in situ Fourier transform IR reflection-absorption spectroscopy in the potential range of 4 . 7 6 to +0.46 V vs. Hg/HgO, OH-. The linear CO persisted on Pt in the entire potential range with gradual shifts to higher frequen- cies, ca. 70 cm- IN, while the bridged CO disap- peared as the electrode potential reached -0.05 V. A potential excursion up to + 0.46 V was found to cause a pH swing of more than 8 in the spectroelec- trochemical thin layer due to glucose oxidation.

Anodic Oxidation of Phenol for Waste Water Treatment CH. COMNINELLIS and C. PULGARIN, 3. Appl. Elec- rrochem., 1991, 21, (S), 703-708 The electrochemical oxidation of phenol for use with waste water treatment has been studied in a two compartment cell at a cylindrical Pt anode of surface area 35 cm’ and 4 cm2 Pt spiral cathode, enclosed in a porous porcelain pot. The reaction was found to occur by two parallel pathways, chemical oxidation with electrogenerated hydmxyl radicals and direct combustion of adsorbed phenol and/or its aromatic intermediates to CO, .

I. T. BAE, E. YEAGER, X XING and C. C. LIU, 3. Elec-


High Temperature Air Cathodes Contain- ing Ion Conductive Oxides T. KENJO, S. OSAWA and K. FUJIKAWA, 3. Electrochem.

Ion conductive oxides were introduced into F’t electrodes to see if they would behave as liquid electrolyte penetrating the porous electrodes. The mixed electrodes were expected to operate as a pore whose inner wall was covered with a gas permeable electrolyte film, in which the electrode performance should increase with increasing electrode thickness. However,

ditions produced no marked improvement, while (Bi20,)u 7(Er20J)0. , exhibited the expected trend, giving a much higher performance than simple Pt/ZrO, electrodes.

Electrochemical Charging of Pd Rods

Electroanal. Chem. Interfacial Electrockem., 1991, 309, (1 and 2), 273-292 A model describing the electrochemical charging of Pd rod and featuring the coupling of the interfacial processes with the transport of intemitials in the Pd electrode interior is presented. It is shown that boundary conditions arise kom the solution of equations governing the elementary adsorptiondesorption and adsorption-absorption steps and electrode symmetry.

The Indirect Anodic Oxidation of 2-Methylnaphthalene. Part 1. Ruthenium Compounds as Catalysts S. CHOCRON and M. MICHMAN, J. Mol. catal . , 1991,

The indirect anodic oxidation of 2-methylnaphthalene and naphthalene to 2-methylnaphthoquinone-1,4 and naphthoquinone, respectively, was carried out with RuC1,.3Hz0, Ru(acac), and Ru(NH,),CI, as catalysts, in an un- divided cell using Pt electrodes. RuCl,.3Hz0 or Ru(NH,),Cl, increased the selectivity for quinone formation, whereas Ru(acac) had no effect. Voltam- metry showed that RuCI,.3H,O and Ru(acac), oxidised H,O and not the hydrocarbon.

SOC., 1991, 138, (2), 349-355

(ZrO,) u, qz (Y, 0, ) o and (CeO,) . (SmO ,. d o . ad-

S. SZPAK, C. J. GABRIEL, J. J. SMITH and R. J. NOWAK, J.

66, (I), 85-98

PHOTOCONVERSION Hydrogen Evolution over a Powdered Semiconductor Photocatalyst

Res., 1991, 30, (7), 1634-1638 The rates of H, evolution from a H,O-MeOH mixture containing a dispersed semiconductor Pt/TiO, photocatalyst of colloidal, porous particle or thin film forms were compared with catalyst morphology. A porous particle catalyst has increased surface area compared to its light absorbing area, with decreased particle sue, which increases the duration of the initial high H, evolution rate. The porous catalyst maintains high catalyst activity for a long period of time, and H, evolves in the solar collector.

T. MARWAMA and T. NISHIMOTO, Id. Eng. Chem.

Linear Chains of Pt(bpy)(CN), at Elec- trode Surfaces by Partial Reduction of the Bipyridine ?r System

Chem., 1991, 95, (12), 48004803 Spectrochemical properties of Pt(bpy)(CN), (1) are reported on both polished Pt and roughened Ag electrodes. There is a weak emission and a very strong resonance Raman spectrum (RRS) with visible excita- tion, and (1) may form linear chains on both surfaces. The emission and RRS are very potential dependent (-500*50 mV), the approximate E, ,* of the bpy reduction and the RRS consist exclusively of bpy modes; thus linear chain growth may be due to partial reduction of the bpy T system, and visible absorption to a A+** transition.

Preparation of Ruthenium(1I) Complex- Containing Polymer Monolayers and Langmuir-Blodgett Films T. MIYASHITA, n. S A I T O ~ ~ ~ M. MATSUDA, Chem. Lett. Jpn., 1991, (5), 859-862 Studies of the spreading behaviour of the copolymers

methyL2,2’-bipyridine) and N-dodecylacrylamide (DDA) showed that they form a stable condensed monolayer on a HzO surface. The monolayers could be transferred onto solid supports, yielding the Y- type (bilayer type) Ru(I1) complex contained in polymer Langmuir-Blodgett films.

Kinetics and Mechanisms of the Photo- Induced Oxidation of Ascorbic Acid by Molecular Oxygen Catalyzed by Ruthenium(I1) Complexes Containing 2,2’-Bipyridine and 2,2’-Bipyrazine K. TSUKAHARA, Y. WADA and M. KIMURA, Bull. Chem.

HzOz was efficiently produced by the irradiation of visible light on aqueous acid solutions containing ascorbic acid, 0, and Ru(1I) complexes:

bipyridine and bpz = 2,2’-bipyrazine). The formation of H,O, and the decay of ascorbic acid were followed by polarography during continuous irradiation of the solution by visible light.

Chemically Initiated Electron-Exchanged Luminescence of Ru(bpy) C1, in Catalytic Reaction with 1,2-Dioxetane

TOLSTIKOV, Izv. Akad. Nauk SSSR, Ser. Khim.,

Studies of activated Ru(bpy) , C1 chemiluminescence during decomposition of 1,2-dioxetane were performed. The results showed that kinetics and activity of chemiluminescence of 1,2-dioxetane chemically initiated by the Ru complex proceeded according to the mechanism of chemical initiation of electron- exchange, thus effectively exciting Ru(bpy), CI , and giving an excited $J*R” yield of 0.20 * 0.05.

J. B. COOPER, S. M. N O D E S and D. W. WERTZ, 3. Phys.

of [R~(bpy),(Vbpy)l~ + (Vbpy = 4-vinyl-4’-

SOC. 3p., 1991, 64, (3), 908-915

[R~~(bpy) , (bp~)~, l~+ (X = 0-3, bpy = 2,2’-

A. I. VOLOSHIN, G. L. SHARIF’OV, V. P. KAZAKOV and G. A.

1991, (6), 1316-1321


Laser-Induced Modulation of Second- Harmonic Light Emission from Ru(I1)- Bipyridine Metal Complex in Langmuir- Blodgett Film H. SAKAGUCHI, T. NAGAMURA and T. MATSUO, 3pn. 3. Appl. Phys., Part II Lett., 1991, 30, (3A), L377-I.379 When a Langmuir-Blodgett film containing Ru(I1) bipyridine metal complex was irradiated by a Nd- YAG laser, strong second-harmonic light of 532 nm was observed. However, the intensity of this light is remarkably suppressed when the Ru complex is excited by either 355 or 460 nm laser pulses, just before laser irradiation at 1064 nm. This is ascribed to the reduction in hyperpolarisability on going from the ground state to a metal-to-ligand charge transferred excited state. Thus optical modulation of second harmonic light on this film by laser light provides a novel way of achieving an optical switch.

ELECTRODEPOSITION AND SURFACE COATINGS Preparation of a Pt-GaAs Schottky Con- tact by Ion Plating G. PET0 and T. ANDERSON, Solid-state Electron.,

A tentative investigation has been made to determine if superior intimate metal-semiconductor contact can be achieved by ion plating, and if the negligible surface damage caused would improve the quality of Schottky contacts. A 5000 A Pt layer was evaporated onto a Si doped GaAs wafer, which was subjected to an ion accelerating negative bias voltage (LJ,) during evaporation. I-Vcurves for 4 values of U, are given; increasing UB improves the characteristics of Schot- tky contacts, and ion plating improved the diode.

Sputter Deposition of Cobalt-Palladium Multilayers R. J. HIGHMORE, w. c. SHIH, R E. SOMEKH and 1. E. EVETTS,3. Vac. Sci. Technol. A , 1991,9,(4),2123-2127 Ultrahigh vacuum DC magnetron sputtering has been used to deposit Co-Pd multilayers onto unheated (1 11) Si substrates; and the films have been characterised. Variations in the microstructure and magnetic properties of the films as the sputtering pressure was altered have been observed; changes in magnetic properties are related to microstructure.

Galvanic Ni/PdNi/Au Laminar Composite for Electrotechnical Applications G. BAR and D. RUHLICKE, Metall, 1991, 45, (7),

The electroplated layer combination: Ni/PdNi/Au, containing 80 wt.% Pd-20 wt.% Ni, which is used as a contact material for connectors and contacts in electronic applications is investigated. The coating is performed on previously punched contact strips in a continuous electroplating process, by dip and spot plating. Applications for Ni/PdNi/Au are discussed.

1991, 34, (6), 591-592

668-673

APPARATUS AND TECHNIQUE STM Fabrication of Platinum Disks of Nanometer Dimensions

trochem. SOC., 1991, 138, (2), 641-642 Inlaid Pt disks of 5-36 nm radius were fabricated using scanning tunneling microscopy and tunneling spectroscopy. The Pt was deposited on mica, then a Ti film was electron beam deposited onto the substrate, and exposed to air. A small area of the TiO, layer was selectively removed from the underly- ing Pt surface by placing the STM tip at a fried distance above the surface and a voltage bias was linearly cycled (80 V/s) between positive and negative limits. The Pt disk size can be controlled by changing the tip to surface distance and/or the voltage scanned.

Portable in situ Wall-Rock Thermal Con- ductivity Meter for Mine Pits

strum., 1991, 62, (6), 1581-1586 A novel ring heat source probe, based on three- dimensional transient heat conduction from a point source, is incorporated in a device modified for the in situ measurement of wall-rock thermal conductivity in coal mines, following minimal preparation of the rock surface. Measuring, controlling and power supply systems are enclosed in a sealed container into which thermal conductivity and environmental temperature probes are plugged. The latter consists of a mini Pt resistor.

N. CASILLAS, S. R. SNYDER and H. S. WHITE, J. Elec-

X:J. SHEN, S.-Z. YANG and W.-R. ZHANG, Rev. sci. In-

How a Limited Mass Transfer in the Gas Phase May Affect the Steady-State Response of a Pd-MOS Hydrogen Sensor u . ACKELID and L.-G. PETERSSON, Sew. Actuawn B,

The H, sensitivity of Pd MOS sensors in an 0, containing atmosphere is shown to depend on the area of the Pd film, the rate of the gas flow, the total pressure and the type of carrier gas. Limited mass transfer in the gas phase can explain all the observations, and is confumed by mass spectrometric studies using a local gas-sampling technique. It is suggested that such sensors be calibrated in situ under realistic conditions, since the larger the Pd area the more important this will be.

Progress in Hydrogen Detection: A New Photopyroelectric Device C. CHRISTOFIDES and A. MANDELIS, Int. 3. Hydrogen Energy, 1991, 16, (8), 577-578 A new and inexpensive H, detector has been developed which can operate through a broad range of low temperatures (-190 to +53OC). The structure contains a Pd-polyvinylidene fluoride detector. The thickness of the Pd layer evaporated on the PVDF film plays an important role in determinimg sensitivity and durability of the H sensor. The detector is very sensitive, even for concentrations down to 40 ppm.

1991, 3, (2), 139-146


Reduction of the Interference Caused by NO and SO2 in the CO Response of Pd- Catalysed SnO, Combustion Gas Sensors H. TORVELA, J. HUUSKO and v. LAmo, sens. Actuators

Studies of SnO, -based semiconductor gas sensors containing 0.05,0.1, 1 and 3 mol YO Pd showed that they can be used to monitor the concentration of CO in combustion gases in the presence of NO and SO,. By increasing the sensor temperature to > 500OC the interference effects of NO and SO, on the conductance response to CO could be nearly eliminated. The best conductance response to CO was obtained with sensors containing - 0.5 mol YO Pd. The best response characteristics for thick film paste was obtained on adding Pd to SnO, in the chloride form followed by calcination at 900OC.

Detection of Hydrogen from the Photodissociative Splitting of Water through Hydrogen-Oxygen Separation over a Thin Film H. DANNETIJN, I. LUNDSTR~M and L.-G. PETERSSON, 3.

The photodissociative splitting of water was studied in the gas phase under UV on a plane solid surface of 1-2 nm of TiO, coating on Pd-MOS. A natural separation of the produced H and 0 occurs over the Pd fdm; H diffuses to the Pd/SiO, interface and 0 stays at the Ti0,-Pd surface. The H was monitored by the electric behaviour of the MOS device. Thus suitably treated thin Pd membranes may be used to study the continuous photodissociation of water.

A Model for Sheet Resistivity of RuO, Thick Film Resistors R. W. VEST, IEEE Trans. Components, Hybrids, Manuf. Technol., 1991, 14, (2), 396-406 A study of the microstructure composition relationship of Ru0,-based thick film resistors has been carried out using the results of recent investigations, in order to develop an improved loading curve model. Five types of microstructure are possible, depending upon the volume fraction (V,) of RuO,. A theoretical loading curve model has been developed for 0.032 < V, < 0.24, which is in excellent agreement with the results for a system using glass with high RuO, solubility.

B, 1991, 4, (3 & 4), 479-484

Appl. Phys., 1991, 70, (l), 453-456

JOINING Platinum SiIicide Fusion Bonding M. S. ISMAIL and R. w. BOWER, Electron. Lett., 1991,

Silicide direct bonding between PtSi coated Si wafers and both PtSi coated and uncoated silicon wafers has been successfully carried out after the PtSi surface had been rendered hydrophilic by a selective etching and cleaning process. The PtSi conductive medium provides relatively low resistance interconnections between circuit elements on the bonded pair of wafers, and the technique has potential for 3D ICs.

27, (13), 1153-1154

HETEROGENEOUS CATALYSIS Morphology and Site Blocking Effects on Chemisorption Properties and Reactivity of Pt/Ti02 and Sulfided Pt/AI,03 Catalysts

(2), 359-373 Surface inhibition effects due to S poisoning or strong metal-support interaction were compared on small Pt particles supported on Al,Ol and TiO,. The change in properties was monitored either by H, or CO chemisorption at room temperature or by n-butane hydrogenolysis and isomerisation. The surface inhibition took place in two steps; fmt, an apparent flatten- ing of the particles that leads to less active, low-index-planes-exposure to reactants and to a compensation effect. This occurs at 773 K on Pt/q-Al 0, and at 573 K in the presence of S or TiO,. Then, following a high temperature reduction, the second step takes place by simple site blocking by S or TiO, moieties and does not lead to compensation.

Kinetics of Deactivation of Bifunctional PtlAl, 0 , -C1 Catalysts by Coking

L. BONNEVIoTand G. L. HALLER, 3. catal., 1991, 130,

J. N. BELTRAMINI, T. J. WESSEL and R. DATTA, AIChE 3., 1991, 37, (6), 845-854 The catalytic activity, product selectivity and coke deposition were studied during methylcyclopentane (MCP) reforming on bifunctional Pt/Al, 0 -C1 catalysts with different metal loadings, but constant Pt dispersions and constant Cl loading. The overall conversion of MCP decreased as the metal content of the catalyst increased. The change of activity of the metal and acid functions with time was monitored by following the rates of hydrogenolysis and hydrocracking, respectively. A mechanistically based dual site model for the kinetics of coke formation and the resulting deactivation was developed, which accounts for the deactivation of both the metal and the acid functions.

CH, and CH,I Chemistry on Pt(l11): The Influence of CO

Sci., 1991, 248, (3), 279-286 The surface chemistry of CH I alone and coadsorbed with CO on Pt(ll1) was studied by various techniques. CH I bonds to Pt( 11 1) through lone pair electrons on the halide with a molecular symmetry less than C1, and is not significantly affected by coadsorbed CO. On a clean surface CH I decomposes to CH, and I at - 250 K. CH, is formed at 290 K from the hydrogenation of CHI groups using H from the decomposition of other CHI groups. The competition between CH hydrogenation and dehydrogenation depends on coverage. For a surface dosed with CH , I, then saturated with CO, more thermal energy must be added to break the C-I bond. If CHI is formed fmt, followed by CO to saturation, CH, formation occurs at 40 K lower and with a higher yield than in the absence of CO.

M. A. ANDERSON, G. E. MITCHELLand J. M. WHITE, surf.


Process Gas Filtration in Nitric Acid Production

A discussion of process gas fdtration units and their behaviour upstream of the catalyst in nitric acid plants is presented. It is suggested that stainless steel filters are beneficial in protecting the catalyst from contaminants. Fe, either bonded to the Pt catalyst or as loose fine particles, catalyses the competing reaction in which the NH, feed is oxidised to N, and water vapour. This reaction releases much more heat than the desired reaction and wastes NH, . Si acts as a catalyst poison and deactivates the surface. Other contaminants include phosphates, Pb, Ni and Cr and to a much smaller extent Ca. Me and Ba.

E.BAURand F. K. PETHICK, Nitrogen, 1991, (192), 19-22

Effects of Acidic and Basic Properties on Selectivity m the Reforming of n-Hexane over a Binary Oxide of Titanium and Z i r - conium Supporting a Platinum Catalyst

Catal., 1991, 75, (2) , 331-342 A Pt catalyst on a binary oxide support, Ti0,-ZrO,, having both acid and base sites, was used in reforming n-heme. When the distance between acid and base sites is shorter than the length of the reactant molecule, the active sites on the support are: an adjacent pair of acid-base sites and a lone acid site. The rates of the cyclic and aromatisation reactions increase linearly with the number of adjacent pairs of acid-base sites. Reaction rates for cracking and isomerisation are proportional to the number of lone acid sites. The selectivity in the cyclic and aromatisation reactions therefore can be enhanced by increasing the number of adjacent pairs of acid-base sites and decreasing the number of lone acid sites. The support with a 50% content of TiO, has more adjacent pairs of acid-base sites and fewer lone acid sites than does a commercial catalyst. Hence the selectivity of the sum of the cyclic and aromatisation reactions over the 50% catalyst is higher (62%) than that of the commercial catalyst.

Structure and Activity of Composite Oxide Supported Platinum-Iridium Catalysts

K. HASHIMOTO, T. MASUDA and H. KASHIHARA, Appl.

S. SUBRAMANIAN and J. A. SCHWARZ, Appl. Catal., 1991, 74, (l), 65-81 Pt mobility, Tiox mobility and Al’+ readsorption were found to affect the structure and activity of Pt-Ir catalysts supported on Al,O,, TiO,, Al,O,-TiO, and TiO, -Al, 0 during study by TPRdRPD and by ethane hydrogenolysis. TPRd and ethane hydrogenolysis suggest that bimetal formation occurs when pure oxide supports are used, and bimetal formation is suppressed when composite oxides are used. TiO, acts as a ‘spacer’ and inhibits the mobility of Pt and thus prevents Pt and Ir from forming bimetallic clusters. Bimetal formation is assessed as a function of the support, and models for the structures of the calcined precursor and finished catalysts are proposed.

Heterogeneous Catalysis on Platinum and Self-Assembled Monolayers on Metal and Metal Oxide Surfaces

WHITESIDES, Pure Appl. Chem., 1991,63, (6), 821-828 A series of Pt complexes, CODPt(CD,),, CODPt(CH,CD,),, and CODPt(CH,C(CD,),),, CODPt(CH , C(CH , ) ,(CH ,).CD,) , (n = 1-3) were synthesised and then hydrogenated under mass- transfer limited conditions over Pt black in n-heptane. Heterogeneous Pt catalysts were used in the hydrogenation of diolefm(dialkyl)Pt(II) complexes. The incorporation of D from isotopically labelled protic solvents was particularly useful mechanistically.

Hydrogenation of Acetylene at Transient Conditions in the Presence of Olefms and Carbon Monoxide over Palladium/ Alumina L. CIDER and N.-H. SCHOON, I d . Eng. Chem. Res.,

An egg-shell Pd/a-Al,O, catalyst in a well-mixed reactor, which behaved as an ideal tank reactor, was used in the hydrogenation of C, H,, C,H, and propylene. The conditions used were transient, being caused by cross-desorption of CO due to a pulse of C,H,. A simple model can explain the competition for the active sites and the difference in reactivity. The propylene was added to make it possible to discriminate between the hydrogenation of the olefm (propylene) present in excess in the inflow gas and the olefin (C,H,) formed by the C,H, hydrogenation.

Hydrogenation of Phenol to Cyclohex- anone over Pd/MgO

J. Chem. Tech. Biotechnol., 1991, 51, (2), 145-153 Hydrogenation of phenol to cyclohexanone on a series of Pd/MgO catalysts was studied at 16O-25O0C. At 16OoC, the reaction orders found on all catalysts were - -1 with respect to phenol and - + 1 with respect to H,. The kinetic data showed that the rate determining step is the surface reaction between phenol and H , adsorbed on the catalyst. An increase in the reaction temperature decreased the rate of reaction.

Heterocyclization Reaction Sites on the Sulfided Pd( l l1) Surface

The sulphided Pd(ll1) surface can cyclise C,H, to both benzene and thiophene. The reactions are sensitive to the temperature of preparation of the sulphided surfaces, giving the greatest yield on surfaces produced at temperatures > 1000 K. CO adsorption shows that heating the surface introduces defects at which CO can bind in bridging sites between exposed Pd atoms. This defect concentration, as determined by CO adsorption in bridging sites, is correlated with the amount of thiophene produced from C,H,. Heterocyclisation of C,H, is thus a defect catalysed reaction.

T. RANDALL LEE, P. E. LAIBINIS, 1. P. FOLKERS and G. M.

1991, 30, (7), 1437-1443

S. GALVAGNO, A. DONATO, G. NERl and R. PIETROPAOLO,

A. J. GELLMANN, Langmuir, 1991, 7, (5), 827-830


Characterization of Rhodium Catalysts Supported on Various Inorganic Oxides for Carbon Monoxide Hydrogenation R. M. SANYAL, D. K. GHORAI, D. R. DUTTA, S. K. ADHYA, B. SEN and B. VISWANATHAN, Appl. Catd., 1991, 74, (2), 153-161 Rh catalysts prepared by impregnation of Rh,(CO) ,, on y-A,O,, ZrO,, ZnO and MgO have been characterised by IR, X P S , and UV-VIS. The Rh cluster is oxidatively degraded with time when kept exposed to air. On the first two supports [Rh(CO),XI type dicarbonyl species are produced while on ZnO the Rh,(CO),, keeps its nuclearity, and on MgO species of type [Rh(CO),X,] are formed. Acidic oxides selectively form CH, , while basic oxides favour mainly MeOH on CO hydrogenation.

The CO/H, Reaction on RhlMgO Studied by Transient Isotopic Methods A. M. EFSTATHIOU, J . Mol. Coral., 1991, 67, (2),

Various transient isotopic methods were used to study the COM, reaction over 2.5 wt.% Rh/MgO at 493-573 K. The steps for CH, formation pass through a large reservoir of surface CO and through a small reservoir of active C. Rate control is largely determined by the rate of CO dissociation on the metal surface. Formate on the support may be an active intermediate to make CO,. Two pools of surface CO, a-CO* which readily exchanges with gaseous CO, and (3-C0* which does not, are present on Rh and take part in the methanation. @CO* increases with time on stream at 563 K. Some a-CO* and (3- CO* interact with -OH groups of the support to give CO, and H, , probably via a formate intermediate.

Kinetics of Heterogeneous Catalytic Hydroformylation of Propylene on Rhodium-Cobalt Catalysts. Reaction Mechanism s. I. REUT, G. L. KAMALOV and G. 1. GOLODETS, React. Kinet. Catal. Lett., 1991, 44, (l), 191-195 Steady state kinetics of combined heterogeneous catalytic hydrogenation and hydroformylation of propylene on Rh-Co catalysts supported on Al, 0 ,, MgO or SiO,, have been studied at atmospheric pressure and 14O-17O0C. A reaction mechanism is suggested.

Gas-Phase Hydroformylation of Pro- pylene on Ru/Si02 Catalysts

229-249

S. B. HALLIGUDI, M. M. TAQUI KHAN, B. L. MOROZ, A. L. CHUVILIN, 1. P. PROSVIRIN and V. A LIKHOLOBOV, React. Kinet. Catal. Lett., 1991, 44, (l), 139-146 Studies of Ru/SiO, catalysts performed during gas- phase hydroformylation of propylene showed that catalysts prepared by reduction of supported Ru- Cl , .xH,O were active at low pressure ( - 0.3 MPa) of H, + CO + C,H, mixture with very high selectivity towards unbranched oxo-products. The effect of electronic state and dispersity of Ru on their catalytic behaviour was studied.

Chemistry in Cages: Synthesis and Rever- sible Decarbonylation of [Ir 6 (CO) 16 1 Isomers in NaY Zeolite

mun., 1991, (15), 994-995 A simple synthesis of two isomers of [Ir, (CO) ,, 1 from [Ir(CO),(acac)l in the supercages of Nay zeolite is reported. [Ir(CO),(acac)l in Nay zeolite cages was converted in CO at a pressure of 1 bar to the isomer of [Ir , (CO) 16 I with edge-bridging CO ligands and in CO + H, at 20 bar to the isomer of [Ir,(CO),,l with face-bridging ligands.

S. KAWI and B. C. GATES, J. C h . SOC., Chm. Com-

HOMOGENEOUS CATALYSIS Synthesis of Carbonyl-Olefm Complexes of Platinum(II), PtX, (CO)(Olefm), and the Catalytic Hydroehlorination of Olefms

N. PASQUALETTI and c A. VERACINI, Organometalks,

The mixed olefm-carbonyl complexes of Pt(II), PtX,(CO)(C,H,,) (X = Cl, Br) were prepared by the reaction of PtX,(CO), with cyclohexene, or from R,CI,(CO), and the olefm. The olefm ligand was promptly displaced by CO. The chloro-carbonyl complex PtCl,(CO)(C,H,,) reacted with dry HCl to yield cyclohexyl chloride and Pt , Cl, (CO) I . The mixed carbonyl-cyclohexene complex, or PtCl, (CO), or Pt,Cl,(CO), were found to be effective catalyst precursors for the hydrochlorination with dry HCI of a number of symmetrical, terminal and internal olefms, in hydrocarbon or chlorinated solvents.

Palladium-Catalyzed Hetero-Cope Rear- rangement of Alkyl Allyl N- Aryldithiocarbonimidates

H. ALPER, Y. HUANG, D. 8. DELL’AMICO, F. CALDERAZZO,

1991, 10, (6), 1665-1671

J. GARIN, E. MELENDEZ, F. L. MERCHAN, T. TEJERO, S. URIELand J. AYESTARAN, $JdeSiS, 1991, (2), 147-149 Allyl methyl N-aryldithiocarbonimidates (1) were smoothly rearranged to methyl N-allyl-N- aryldithiocarbamates in the presence of PdCl,(PhCN), catalyst. Very high yields of rearranged products can be obtained depending on the substitution pattern of the ally1 group.

Palladium-Catalyzed Coupling of Aryl Iodides, Nonconjugated Dienes, and Car- bon Nucleophiles by Palladium Migration R. C. LAROCK, Y.-D. LU, A C. BAIN and C. E. RUSSELL, 3. Org. Ckm., 1991, 56, (15), 4589-4590 Aryl iodides, non-conjugated dienes and C nucleophiles reacted in the presence of Pd catalysts (PdCl,, Pd(OAc),, Pd(PPh,), and Pd(dba),) at 60-120°C to give good yields of coupled products. The coupled products are apparently formed by aryl Pd generation and addition to the less substituted end of the diene, Pd migration down the C chain to form a r-ally1 Pd intermediate and carbanion displacement of the Pd moiety.


Catalytic System PdCl, /Ph,PC, H, SO,Na in the Hydrocarboxylation of 1-Heptene

and 2. E. PETROV, Zh. Obshch. Khim., 1991, 61, (3),

Studies of the hydrocarboxylation reaction of 1-heptene catalysed by PdCI2 in the presence of Na salt m-sulphophenylene diphenylphosphine were performed, and reported. The catalytic system PdQ,Ph,PC,H,SO,Na-m was more effective during hydrocarboxylation of olefme than the analogous system with Ph, and it also allowed the reaction to proceed in media with high H,O content.

5-Vinyl-4-Pentynoic Acids through the Palladium-Catalyzed Reaction of 4-Pentynoic Acid with Vinyl Triflates

L. F. STAROSEL'SKAYA, T. E. KRON, M. 1. TEREKHOVA

736-739

A. ARCADI, S. CACCHI, M. DELMASTRO and F. MARINELLA, Synlett, 1991, (6), 409411 The reaction of vinyl triflates (1-cycloalkenyl trifluoromethanesulphonates) and 4-pentynoic acid at room temperature in dimethyl sulphoxide in the presence of diethylamine or diisopropylamine and catalytic amounts of [Pd(OAc),(PPh,),l and Cu(1) iodide, gave a high yield of a variety of 5-vinyl-4-pentyioic acids. The best results were obtained on addition of DMSO to the reaction mixture. Good results were also obtained in the absence of solvents or using MeCN and DMF.

Palladium-Catalyzed Coupling of Allcenyl Iodonium Salts with Olefms: A Mild and Stereoselective Heck-Type Reaction Us- ing Hypervalent Iodine

Chem. SOL., 1991, 113, (16), 6315-6317 A catalysis using Pd(0Ac) , and giving a variation of C-C coupling with phenyl(alkeny1)iodonium salts and various alkenes is presented. The reaction occurs at room temperature and polymerisation of activated olefms at > 100°C, which occurs in the Heck reaction, does not happen. A wide range of structural types are available and high yields are produced.

Palladium-Catalyzed Synthesis of N,W- Diphenylurea from Nitrobenzene, Aniline, and Carbon Monoxide

Eng. Chem. R e . , 1991, 30, (7, 1456-1461 N,N'-Diphenylurea has been synthesised from nitrobenzene, aniline and CO at 80-160OCand 15-75 bar. A homogeneous catalyst system of a Pd(I1) salt, an onium salt and triphenylphosphine dissolved in xylene or toluene was highly efficient in giving isolated urea yields of up 98% at 100% nitrobenzene conversion. The reaction consumed more aniline than nitrobenzene on a molar basis, suggesting the existence of a new reaction path in addition to the usual path where equimolar amounts of aniline and nitrobenzene are consumed. Excess aniline enabled the catalyst system to be reused.

R. M. MORIARTY, W. R. EPA and A. K. AWASTHI, 3. Am.

I. S. OH, S. M. LEE, 1. KYEO, C. W. LEEand J. S. LEE, Id.

Facile Aryl-Aryl Exchange between the Palladium Center and Phosphine Ligands in Palladium(I1) Complexes K.-C. KONG and C.-H. CHENG, 3. Am. Chem. SOC., 1991, 113, (16), 6313-6315 A facile two-way aryl migration between the metal centre and co-ordinated phosphine in Pd(I1) complexes is reported. When Pd(PPh,),(C,H,-p-CH,)I, after preparation from the oxidative addition of p- iodotoluene to Pd(PPh,), , was heated at 50-6OoC in THF or chloroform, a regiospecific exchange between the aryl on the Pd centre and the phenyls on the phosphine occurred. The reaction was monitored by IH NMR spectroscopy.

Palladium-Catalyzed Oxyhexatriene Cyclization: A Novel Approach to Cyclohexenone Annulation c. M. H E T T R I C K ~ ~ ~ w. J. scorn, 3. Am. Chem. SOC., 1991, 113, (13), 49034910 A general approach to the hexatriene cyclisation of dienone enolates or their derivatives is afforded by converting fully conjugated dienones to the kinetic enolates with kinetic silyl ethers and trapping as the silyl enol ethers; heating these in toluene or xylenes in the presence of 5 mol% Pd(PFu,),Cl,, where Fu is furyl, gives the corresponding cyclohexenones in good yield. Thermal electrocyclisation of electron- rich hexatrienes may be diffEult. Pd(PFu,),Cl, is proposed to mediate the cyclisation of [(trimethylsilyl)oxyl hexatrienes by causing Pd enolate formation, followed by addition across a C = C bond and trapping the annulated product as the silyl enol ether.

The Effect of Metal Colloid Morphology on Catalytic Activity: Further Proof of the Intermediacy of Colloids in the Rhodium- Catalyzed Hydrosilylation Reaction L. N. LEWIS, R. J. URIARTE and N. LEWIS, 3. MOl. Catal., 1991, 156, (l), 105-113 The relative activity of different morphological forms of Rh colloids were examined by TEM and HREM. The degree of agglomeration of the Rh colloid was affected by either its storage or by the use of a vinyl silicone stabiliser. The smaller particle size (higher surface area) yellow Rh colloid was more active than the larger particle size red Rh colloid, but a black Rh colloid, which had no stabiliser, was most active.

Enantioselective Hydroborations Catalyz- ed by Rhodium( + 1) Complexes

Tetrahedron: Asymmety, 1991, 2 , (7), 613-621 Enantioselective hydroborations of alkenes with catecholborane were performed via catalysis with complexes containing the chiral phosphine ligands DIOP, BINAP, CHIRAPHOS, DIPAMP, BDPP, 2-MeODIOP and 3-MeODIOP. Alkenes were also hydroborated with catecholborane derivatives in the presence of Rh( +)/DIOP catalysts.

K. BURGESS, W. A. VAN DER DONK and M. J. OHLMEYER,


Enantioselective Metal Complex Catalysis. 6. Rhodium Catalysts for Asym- metric Hydrosilylation Based on Chiral Phosphites

TELESHEV, L. s. GORSHKOVA, E. E. NIFANT'EV and E. I. KLABUNOVSKII, Izv. h a d . Nauk SSSR, Ser. Khim.,

Studies of asymmetric hydrosilylation of acetophenone by diphenylsilane in the presence of a Rh complex catalyst containing chiral phosphates were performed. Enantioselectivity of the catalyst depended on phosphite formation, on the ratios of acetophenone:Rh and 1igand:Rh and on the temperature of the reaction.

Colloidal Rhodium Suspensions Stabiliz- ed by Various Hydrotropic or Surface Ac- tive Triphenylmethyl Trisulfonates and Their Use in Biphasic Catalysis

Chem., 1991, 15, (15), 361-366 Highly water soluble trisulphonated compounds R- C(p-C,H,SO,Na), bearing polar, non-polar or lipophilic R substituents have been used to stabilise a catalytically active colloidal suspension of polyhydroxylated Rh particles, thus allowing the hydrogenation of liquid alkenes in biphasic media. Stabilisation occurs via adsorption of the polyanionic head group on the polar surface of the hydroxylated Rh particles, affording electrostatic or electrosteric repulsions. The catalyst can be recycled.

Extremely Efficient Catalytic Reduction of Aromatic Nitro Compounds Affording Amines Using Amine-Added Rh,(CO) 16

Catalyst Systems under CO/H20 Con- ditions K. NOMURA, M. ISHINO and M. HAZAMA, 3. Mol. catal.,

Rh,(CO),, catalysts with added small amounts of amines or diamines in 2-methoxyethanol/5 N NaOH aqueous solution exhibit remarkably high activities for the reduction of aromatic nitro compounds: p- nitrotoluene and p-nitroanisole. The reaction conditions are 25OC and 1 atm CO.

Hydroformylation of Oet-1-ene with Ex- tremely High Rates Using Rhodium Catalysts Containing Bulky Phosphites

E. W. ZHOROV, K. N. GAVRILOV, V. A. PAVLOV, A. T.

1991, (9, 983-988

C. LARPENT, F. BRISSE-LE MENN and H. PATIN, NeW 3.

1991, 66, (2), Lll-L13

A. VAN ROOY, E. N. ORIJ, P. C. J. KAMER, F. VAN DEN AARDWEG and P. W. N. M. VAN LEEUWEN, 3. Chem. SOC., Chem. Commun., 1991, (16), 1096-1097 A Rh complex containing tris(o-zert-buty1-p- methylpheny1)phosphite as a ligand catalyses the hydroformylation of oct- 1-ene with good selectivity and at extremely high rates. The rate constant is pseudo first order in [H,I and 1/[CO1 and shows that the reaction of H is the rate determining step. The observed rates are at least 10 times higher than those observed for the Rh triphenylphosphine catalyst.

Hydroformylation of Styrene Catalyzed by Rhodium Complexes with 2-Diphenylphosphinopyridine S. GLADIALI, L. PINNA, C. G. ARENA, E. ROTONDO and F. FARAONE, 3. MOl. catal., 1991, 66, (2), 183-190 Mono- and binuclear Rh complexes containing 2-(diphenylphosphine)pyridine, Ph,PPy (1) as ligand, have been examined as catalysts for styrene hydroformylation. All were good catalysts and the formation of the expected aldehydes took place selectively within several hours in mild conditions. The binuclear catalyst was efficient only under high pressure, whereas the in siru system obtained by addition of (1) to RhH(CO)(PPh,), (2) had a pronounced activity even in the low pressure reaction. In solution (1) can easily displace one or two moles of PPh, from (2) giving rise to mixed mononuclear phosphine-Rh complexes, the most active catalytic species.

Efficient Low-Temperature Thermal Functionalization of Alkanes. Transfer- Dehydrogenation Catalyzed by Rh(PMe,)2CI(CO) in Solution under a High Pressure Dihydrogen Atmosphere

1991, 113, (17), 6706-6708 An efficient catalytic system for alkane dehydrogenation is described which requires an added H, atmosphere; this is because the thermodynamic barrier to CO loss from the Rh(PMe,),Cl(CO) catalyst is overcome by its being coupled with alkene hydrogenation. This affords the reactive fragment Rh(PMe,),Cl, which thermally dehydrogenates alkanes in accordance with photocatalytic behaviour.

Ruthenium Catalyzed Hydroformylation Reactions Using in Situ Generation of Synthesis Gas from Aqueous Methyl Formate

Aqueous methyl formate was used as a source of CO and H, via catalysis with Ru,(CO),, + tricyclohexylphosphine in the hydroformylation of cycloalkenes and linear alkenes. The hydroformylation reaction involved [HRu , (CO) 1 -. The best results for formation of higher alcohols were obtained with lower alkenes. The addition of Pd(acac), was able to modulate the selectivity with respect to the alcohols.

Efficient Ruthenium-Catalysed Transfer Hydrogenation of Ketones by Propan-2-01

Chem. Commun., 1991, (16), 1063-1064 In the presence of co-catalyst NaOH, RuCl,(PPh,), catalyses the efficient transfer hydrogenation of both aliphatic and aromatic ketones by propan-2-01, at rates of up to 900 turnoversh at 82OC. No hydrogenation occurs in the absence of NaOH. Using NaOH dramatically improves such reported hydrogenations, run under neutral conditions.

J. A. MAGUIRE and A. S. GOLDMAN, 3. Am. Chem. SOC.,

G. JENNER, catal., 1991, 75, (2), 289-298

R. L. CHOWDHURY and J.-E. BACKVALL, 3. Chem. SOC.,


FUEL CELLS Dependence of Performance of Solid Polymer Electrolyte Fuel Cells with Low Platinum Loading on Morphologic Characteristics of the Electrodes

Appl. Electrochem., 1991, 21, (7), 597-605 Pt electrocatalysts supported on C and also low catalyst loading gasdiffusion electrodes used in protonsxchange-membrane (PEM) fuel cells were studied by TEM and SEM and/or Rutherford backscattering spectroscopic analyses. The results showed an increase in Pt cryaallite sizes when the Pt:C weight ratio increases in the order 10,ZO and 40 wt.% Pt/C electrocatalyst; and that the Pt:C ratio is 1:2.4:4 for the electrodes with 10, 20 and 40 wt.% Pt/C, respectively. It is concluded that the use of electrodes with thin catalyst layers, of high Pt:C ratio, with Pt localised near the front surface had the effect of diminishing the overpotentials in PEM fuel cells.

E. A. TICIANELLI, J. G. BEERY and S. SRINIVASAN, J .

ELECTRONIC AND ELECTRICAL ENGINEERING Thermal Stability of Au-Sn/Near Noble Metal Barrier Metallization Systems 0. WADA and T. KUMAI, Jpn. 3. Appl. Phys., Parr 11 Len, 1991, 30, (6A), L1056-Ll058 The reaction barrier characteristics and thermal stability of evaporated Pt, Pd and Rh films when used with Au-30 wt.% Sn were studied. Sn in Au-Sn diffused preferentially into a barrier metal uniformly for all three metals; the diffusion coefficients are sufficiently thermally stable over a temperature range relevant for chip bonding and device operations. Rh has the smallest diffusion coefficient between 200 and 4OO0C, with the highest activation energy, 1.95 eV, below the melting point of Au-Sn of 280OC. Thus Pt and especially Rh are useful in highly stable metallisation systems applicable to flipchip integration.

Low-Temperature Formation of the PtSi Layer by Codeposition of Pt and Si in a Molecular Beam Epitaxy System K. mrpt, H. KANAYA, Y. KUMAGAI, F. HASEGAWA and E. YAMAKA, 3pn. 3. Appl. Phys., Part 11 Lett., 1991,

Pt and Si were codeposited on Si(100) to form polycrystalline PtSi layers in a molecular beam epitaxy system. Properties of codeposited Pt silicide layers depend on the substrate temperature and the evaporated Pt:Si ratio. The fdm codeposited at the substrate temperature of 200°C with the stoichiometric ratio of Pt:Si = 1:l had a similar crystallised grain structure, (oriented to [ 1 lo]), and the same resistivity, - 35 pfl an, as those of the PtSi layer formed by the thermal reaction at 5OOOC. The film codeposited at 8OoC and Pt:Si = 1:l or at Pt:Si = 3:4 and ZOOOC showed a smaller grain size and a higher resistivity.

30, (3B), L455-LA57

Preparation of YBa,Cu30, Supercon- ducting Thin Films on Metallic Substrates by Excimer Laser Ablation J. SAITOH, M. FUKUTOMI, K. KOMORI, Y. TANAKA, T. ASANO, H. MAEDA and H. TAKAHAM, Jpn. 3. Appl. Phys., Part I I Lett., 1991, 30, (5B), L898-L900 Superconducting thin films of YBa,Cu,O, on metallic substrates were obtained by a pulsed laser ablation technique. The growth quality of the films was compared on YSUHastelloy substrates with and without a Pt underlayer. A thin Pt film between YSZ and Hastelloy changed into a PtCr , layer on reaction with Cr, and was very effective in suppressing inter- diffusion between YSZ and Hastelloy and in stabilis- ing the YSZ buffer layers, giving well-crystallised YBa,Cu,O, films on them.

Barrier Metals for ULSI: Processing and Reliability D. PRAMANIK and v. JAIN, Solid State Technol., 1991,

Problems encountered in applying barrier metal technology to Si ULSI processing is discussed. Bar- rier metal films separate two materials, such as Al/Si, Au/Si, Au/Si, Al and noble metal silicides such as PtSi, Pd,Si and Nisi,. Very low contact resistances to n+ and p' can be obtained by forming PtSi or Pd,Si in the contacts prior to the barrier metal deposition. For PtSi contacts the Al reacts with PtSi at temperatures as low as 300OC; above 4OOOC the PtSi is a strong sink for Al atoms, and once Al penetrates the TiW barrier, contact failure occurs.

Pd-on-GaAs Schottky Contact: Its Barrier Height and Response to Hydrogen H.-Y. NIEand Y. NANNICHI, 3pn. 3. Appl. Phys., 1991,

A Pd-on-GaAs Schottky contact was prepared by depositing Pd using a W heater, instead of electron beam heating, onto a GaAs surface, and the interface composition was investigated. A reacted interface in the Pd-on-GaAs system characterised a barrier height of 0.88-0.92 eV insensitive to H, . The response to H, was correlated with the barrier height, and the device was sensitive to H, when barrier height was higher than a critical value of - 0.96-0.99 eV.

Size Effects in Ruthenium-Based Thick- Film Resistors: Rutile vs. Pyrochlore- Based Resistors

TOMBESI and T. AKOMOLAFE, Active Passive Elec. Comp., 1991, 14, (3), 163-173 The change of sheet resistance, &, as a function of resistor length has been investigated in resistive layers whose conductive phase evolves from Pb-rich pyrochlores to Pb Ru , 0 b. and finally to RuO , on increasing the firing temperature. Bi diffusion lowers the sheet resistance values in shorter resistors, while Ag diffusion has this effect in shorter resistors only for ruthenate conductive grains, the reverse being noted in Ru0,-based layers.

34, (3, 97-102

30, (9, 906-913

M. PRUDENZIATI, F. SIROTTI, M. SACCHI, B. MORTEN, A.


NEW PA TENTS METALS AND ALLOYS Palladium-Cobalt Alloy Having Static Magnetos triction

An alloy consisting of 40-92% Pd and 60-8% Co with small amounts of impurities is hot worked at 900-140O0C, cold rolled into a wire or strip, heated in air, inert gas or vacuum for more than 1 min at > 900OC to below the melting point, and slow cooled. The alloy has static magnetostriction.

Magnetic Strain Material Used to Control Crystal Orientation TOKIN COW. Japanese Appl. 3124,248 An alloy material able to control its crystal orientation contains Tb, Dy, Fe and one or more of the Pt group elements. The Tb-Dy-Fe alloy is characterised by the presence of Pt andlor Pt group elements in the matrix structure, and has an increased magnetic strain.

Increased Strength Palladium-Platinum

DEW-JIKI ZAIRYO K. Japanese Appl. 3117,248

Alloys SVERD NON-FERR. META. Russian Patent 1,557,192 Alloys of Pd and Pt are implanted with H, by cathodic polarisation in two stages, to increase their strength properties while maintaining the level of plastic characteristics. In an example, the yield point, yield strength and relative elongation of the alloy were increased. The alloys are used in H, diffusion.

CHEMICAL COMPOUNDS Production of Halide-Free Rhodium Nitrate W. C. BRIENZA U.S. Patent 4,983,372 Halide-free Rh(NO,), is prepared by reacting Rh metal with concentrated HQ, gaseous CI, and gaseous HCI to convert to H, RhCI,, reacting with KI to give RhI , , and reacting with HNO and H 0 , to give Rh(NO,),. Halide-free Rh(NO,), is produced quantitatively, and is used as a stable and efficient catalyst. Prior art methods are not quantitative which results in reduced catalyst activity and loss of Rh.

Organic Ruthenium Compound Used for Ink MATSUSHITA ELEC. IND. K.K.

Japanese Appl. 21302,328 An organic Ru compound consisting of at least 2 Ru atoms and 4 anions of 2-hexanoic acid is synthesised by reacting a Ru compound with 2-hexanoic acid in a non-aqueous solvent at < 40OC. The organic Ru compound is produced in hlgh yield, has excellent thermal decomposition properties, high sintering ability, and can be used to form an ink for preparing a film resistor at low temperature.

ELECTROCHEMISTRY Palladium Membranes for Electro- chemically Enhanced Cold Fusion Cell DREXLER TECHN. cow. world Appl. 9112,359A Pd membranes are used for absorption or adsorption of D or Li ions in a cell for the production of thermal energy by conversion of other energy forms. The cell includes a gelatin matrix permeable to D and Li ions so that they can reach suspended Pd metallites. The heat energy generated by the fusion of the ions is used by a heat exchange system in the electrochemically enhanced cold fusion cell.

Palladium Matrix for Retaining Hydrogen in High Density S. D. GUPTA U.S. Patent 4,986,887 A Pd bearing matrix is used to retain H, and its isotopes, obtained by electrolysis of water, in high density. This is effected by electrolysing a solution of a Li salt, an aprotic solvent and water between a Pd bearing cathode and an inert anode at a potential of at least 200 mV above that required for electrolysis of water. H 2 and its isotopes are generated until the cathode is saturated, and H,:Pd ratios of > 0.6, preferably of > 0.95, can be obtained.

Ozone Generator with Platinum Electrodes E. L. KARLSON U.S Patent 4,988,484 An ozone generator has two spaced electrodes, both of which have a catalyst of Pt or Fe oxide to increase ozone generation. The fmt electrode is on a dielectric, the receiving electrode is earthed, and the two electrodes pass a corona discharge across a flow consisting of 0, gas at 250-10,OOO psia. The ozone generator requires less energy per unit of ozone.

Electrolytic Anode with Base Coating Containing Platinum or Iridium JAPAN CARLIT K.K. Japanese Appl. 21294,494 An anode has a valve metal or valve metal alloy as base, a 0.05-3 pm thick base coat layer containing 10-60 mol % Ir oxide or Pt, and 4-90 mol % of at least one oxide of Ti, Zr, Nb, Ta and Sn, and a Pt or Pb02 layer on the base coat layer. The anode is used for electroplating Cr or Sn, for electrolytic collection of metals.

Palladium Cathodes Containing Metal Nitride Grains for Electrolysis SEIKO EPSON COW. Japanese Appl. 21298,288 Cathodes consisting of metallic Pd containing dispersed grains of a metal nitride such as Ti, Zr or Hf, of about 0.1 pm diameter, are used as the electrodes in an electrolytic apparatus for electrolysing heavy water. The apparatus is resistant to high voltage, and durable for a long period of time.


ELECTRODEPOSITION AND SURFACE COATINGS Palladium Electroplating Bath AMERICAN TEL. & TELEG. CO.

European Appl. 415,632A An electroplating bath contains a Pd complex ion source, preferably at 0.05-0.3M, with NH, or an organic amine as the complexing agent, a source of As at O.Ol-O.lM, and may contain surfactants, brighteners and buffers. The bath is used for electroplating jewellery and electrical contacts with I’d; avoiding the problem of H, incorporation in the electroplated layer, and enabling crack-free, thick, ductile layers to be deposited.

Coating Plastic Objects with a Thin Layer of Noble Metal CIBA GEIGY A.G. European Appl. 417,037A A process for coating a plastic object with a layer of noble metal up to 1 pm thick has the novelty that the object contains 2.5-90 wt.% finely divided MnO, NiO, Cu,O, SnO or Bi,O, fder, and is treated with an acidic aqueous solution of at least 0.00001 molA of a salt of Pt, Pd, Rh, Ir, Os, Ru, Au or Ag. Electrically conductive coatings on plastics are obtained.

Hydrogen Storage Body Containing Palladium CANON K.K. Eumpean Appl. 417,802A A H, storage body consists of a 0.2-100 pm thick deposit of ultrafine particles of a storage material, preferably Pd, optionally on a matrix which is also a H, storage material, preferably LaNi,. The H, storage body has applications in H, purification/recovery devices, heat pumps, actuators and cold nuclear fusion electrodes. H, storage is effected in short times at high concentrations, and may be in the form of light H, , deuterium andlor tritium.

Improved Adhesion Electroplating of Electroactive Polymer Substrates MINNESOTA MINING MFG. CO.

Eumpean Appl. 423,947A A polymer substrate with an electroactive nucleus of pyromellitimide is electroplated with a fmt metal from Cu or Sn, and with a second metal from Pt, Pd, Au or Ni, from a solution containing a charge com- pensating cation such as ammonium. The method provides improved adhesion between the substrate and first metal film when exposed to conditions of 85% relative humidity and 85OC.

Rhodium Plating Solution

A plating solution for producing bright Rh plating is based on Rh sulphate, and also contains 0.1-300 gfl of a nitrate as brightener, and 0.001-10 molfl of an amine. The Rh platings provided are used for electrical contacts or ornamental purposes.

ISHIFUKU KINZOKU KO. Japanese Appl. 21301,590

Electrodeposited Iridium Oxide Film HITACHI MAXELL Japanese Appl. 316,288 A new Ir oxide electrodeposited film is obtained by electrodeposition from nitrogen blown alkaline solution containing at most 0.006 molA Ir compounds per Ir atom and at most 0.008 molA oxalic acid as chelating agent. The new electrodeposition film is used for a display electrode for an electrochromic elemental device, and shows good smoothness.

Process for Metal Plating Carbon Fibres MITSUBISHI RAYON K.K. Japanese Appl. 3119,966 C fibre is dipped into a Pd hydrosol containing a surface active agent so that Pd is adsorbed onto the fibre, and then it is electrically plated, for example with Ni. Pd adsorption can be effected using a supersonic bath or by electrical adsorption. The process is simple and speedy, and the metal plated C fibre is used for shielding materials for computer or digital devices, or for a composite material for resisting a thunderbolt.

Durable Anode for Electroplating Tin Films jApm CARLIT K.K. Japanese Appls. 3139,496-97 An electrode used as an anode for electroplating consists of a corrosion-resistant metallic base, preferably low cost Ti, coated with either Ir oxide and Pt at an 1r:Pt molar ratio of 1:9-9:1, or 3-80 mol ‘YO Sn as Sn oxide and Ir oxides andlor Pt. Preparation is by coating a sand-blasted and etched Ti base with compounds of Ir, Pt and optionally Sn, and heating at 400-6OO0C in air. The anode is durable, of low cost, and gives a long life for electroplating Sn fdms from an acidic bath.

Palladium-Silver Alloy Coatings for Electrical Contacts w. c. HERAEUS G.m. b.H. German Appl. 3,935,664 Pd-Ag alloys for electrical contacts are electrolytically deposited from an ammoniacal bath of pH > 8, containing 5-50 gA Pd as a tetramine complex, 2-40 gA Ag as a diamine complex, and 1-50 gA of an organic S compound as brightening agent, for example an aliphatic or aromatic mercapto-compound. The Pd- Ag alloy coatings formed are ductile, pore-free and crack-free.

APPARATUS AND TECHNIQUE Platinum Wire Gas Sensor for Combustible Gas Monitor NEOTRONICS LTD. World Appl. 91/2,243A An active ‘pellistor’ gas sensor consisting of a fine coil of Pt wire coated with ceramic to form a bead and with a surface catalyst to aid gas decomposition may be used in a monitor for detecting combustible gases. The monitor includes a bridge circuit and a balance detector which measures the degree of imbalance in this circuit, to give an output signal of the amount of combustible gas in an atmosphere.


Platinum Counter Electrode for Solid Electrolytic Capacitor Manufacture

A solid electrolytic capacitor is made by placing a phenol resin resist on a flat plate type forming foil, setting a Pt counter electrode through a separator such as glass paper on the resist, and electrolytically polymerising a 5-20 wt.% pyrrole solution to form a polypyrrole f h as solid electrolyte on the forming foil. This method can produce high quality solid electrolytic condensers effectively and simply, for use in electrical and electronic devices, with high efficiency.

High Temperature Strain Gauge with Thin Film Platinum Gauge Pattern HONDA MOTOR IND. K.K. Japanese Appl. 312,603 A strain gauge consists of a thin film gauge pattern of Pt (2-25 pm thick) produced by chemical vapour deposition, formed directly on a test material such as Si,N,, with a protecting f h layer on the gauge pattern. The width of each Pt pattern is 100 pn, with the patterns in parallel and connected to form the gauge pattern. The gauge is used for strain measurement of ceramics, up to about 16OO0C, and has good durability at high temperature.

Platinum Indicator Electrode for Polarographic Determination of Chlorine

The concentration of free effective c1 in solutions containing coexisting free and combined c1 is determined by polarography using a Pt rotating indicator electrode, and a AgCl reference electrode. At least 40 gA KBr is added to the sample solution, and the pH is adjusted to about 6.0. The method is used for residual c1 determination in water and makes possible the accurate determination of effective Cl.

Apparatus for Catalytic Methanol Reforming

NIPWN CHEMICON K.K. Japanese Appl. 21299,215

YOKOGAWA D E W K.K. Japanese Appl. 314,159

MITSUBISHI HEAVY IND. K.K. Japanese Appl. 311 2,302

CH,OH reforming apparatus includes a pipe with fins in a reactor, where the outer surface of the pipe is coated with rutile-type TiO, loaded with Pt andlor Pd. The TiO, coating works as a catalyst and heat conductor so that the size of the apparatus can be reduced, and the temperature conmlled. The apparatus is used to reform CH OH or a CH, OH-H, 0 mixture into a H, containing gas, using the heat of exhaust gas from engines or gas turbines.

Growth of a Barium Borate Single Crystal Using a Platinum Wire NEC CORP. Japanese Appl. 3145,599 A BaB,O, single crystal in a or @ form is grcwn by dipping a Pt wire into the melt and withdrawing, using a high frequency furnace. The 0 crystal grows in symmetry with the Pt wire as the symmetry centre, whereas the rr crystal grows with development of ex- traordinary facets. The crystal form can be judged during growth, which allows correction by switching the high frequency furnace to enable stable growth of the fi crystal.

Recovery and Refining of Rhodium Used as a Water Catalyst NISSAN MOTOR K.K. Japanese Appl. 3147,928 Rh or a Rh containing mixed solution used as a water catalyst for purifying automobile internal combustion engine exhaust can be separated and refined by heating in a mixed solution of nitric acid and per- chloric acid, adding H, 0, for conversion of Rh to Rh nitrate, and then r e f ~ n g Rh nitrate.

Versatile Gas Sensor with Platinum Electrodes M. D. GYULAI German Appl. 3,910,038 A gas sensor used to detect 0,, H,, CO, H,S, SO, and other gases, consists of an electrochemical cell system including a measurement electrode and counter electrode of at least one of Pt, Au, Ag, other noble metals and their alloys, and a reference electrode which may be AglAgO. The sensor sensitivity is made constant over its life by using a reference electrode, and useful life can be extended by regeneration of the counter electrode.

Colorimetric Indicator for Toxic Hydride Gases DRAGERWERK A.G. German Appl. 4,020,753 The presence of hydride gases, especially highly toxic gases such as mine or phosphine, is determined by the colour change of a carrier. The carrier is especially a paper disc or silica gel impregnated with glycol and Pd(I1) chloride solution or Pd tetramine chloride solution. The detector gives a clear colour change even for gas concentrations as low as 0.01 ppm, is resistant to direct sunlight, and is still effective after long storage periods.

Device for Preparation of Ruthenium Salts with Improved Productivity CHEM. REAGENTS PURE Russian Patent 1,560,631

P1atinum-Ziconia for Growing A device giving improved productivity for prepara- Garnet Single Crystals tion of saturated solutions of Ru salts in acids and MATSUSHITA ELEC. IND. K.K.

Japanese &Pl. 3145,589 A crucible consisting of a Pt material with 0.1-2 wt.% dispersed ZrO, is included in a liquid phase epitaxy apparatus used to grow a garnet single crystal. The service life of the crucible is prolonged, and a crystal of low light absorption loss can be obtained.

alkalis includes impulse capacitors charged from a diode bridge through thyristors, with currents set by variable resistors. High power thyristors control the discharge of capacitors through the electrolyser, and the device includes a peak detector which can close the thyristors and prevent breakdown if the impulse current is too high.


Platinum-Ziconia Crucible for Growing Garnet Single Crystals MATSUSHITA ELEC. IND. K.K.

Japanese Appl. 3145,589

HETEROGENEOUS CATALYSIS Platinum-Palladium Catalyst for a Laser Device ELTRO G.m.b.a. European Appl. 408,974A A laser device has a wavelength-shifting Raman cell with a Raman medium in contact with a solid catalyst consisting of a y- and/or q-Al,O, support containing Pt, a few wt.% of Pd, and a few wt.% of one or more of Sb, Mn and Sn. Heterogeneous and homogeneous catalyses are combined, the solid state catalyst being partially saturated with the homogeneous one. The laser device has high efficiency, high power and pulse energy, good divergence, good stability and long life.

Osmium Catalyst for Oxidation of Alkanes RHONE-POULENC CHIMI. European Appl. 410,901A 0s or an 0s compound, especially 0s0, , is used for the catalytic oxidation of alkanes, especially cyclohexane, with H 2 0 , in the liquid phase, at < 15OoC, to give a mixture of alcohols and ketones. The 0 s may be deposited on a support or may be a mineral compound or organic complex which liberates a mineral form of 0s. The claimed process does not reduce the number of C atoms in the molecule.

Selective Palladium Hydrogenation Catalysts BASF A.G. European Appl. 412,4156 Pd hydrogenation catalysts are produced by vapour deposition of Pd metal on a stainless steel support, treating with a ‘metallic inhibitor’, especially Bi, by vapour deposition, and heat treating at 300-800OC. The catalysts are useful for selective hydrogenation of triple bonds to double bonds, especially for conversion of hydro-dehydrolinalool to hydrinalool, giving 99.3-99.5% selectivity at 100% conversion.

Palladium Catalyst Used to Prepare Unsaturated Carbonyl Compounds NIPPON ZEON K.K. European Appl. 41 5,745 A cY,P-Unsaturated carbonyl compounds are prepared by contacting an alkenyl compound with 0, at 0-100°C for 10 min-72 h in a diluent, and in the presence of a catalyst consisting of 0.1-15 wt.% Pd on a porous support. The products are useful in the preparation of perfumes and medicines.

Catalysts for Selective Hydrogenation of Organic Acids BP CHEM. LTD. European Appl. 417,867A A hydrogenation catalyst consists of Rh, Ru or especially Pd alloyed with Au, Cu or especially Ag, and at least one of Re, W and Mo on a support such as high surface area graphitised graphite or an activated C. The catalysts are used for hydrogenation of acetic acid to ethanol and maleic acid or anhydride to y-butyrolactone with low production of alkanes and good inhibition of other by-product formation.

Rhodium Catalyst for Preparation of Lower Aliphatic Alcohols TEXACO INC. U.S. Patent 4,983,638 Lower aliphatic alcohols are prepared by reacting CO and H, at 240-400°C and 500-3500 psig in the presence of a catalyst consisting of 0.5-1.5 wt.% Rh,

1-100 ppm Cl, and optionally a support such as Al,O,. The product is obtained in high yield at relatively low temperature and pressure, and consists of a mixture of CH,OH and 2-6C alcohols, which is used as a blending component in hydrocarbon motor fuels.

Noble Metal Alkaline Zeolites for Catalytic Reforming EXXON RES. & ENG. CO. U.S. Patent 4,992,401 Reforming catalysts with outstanding activity and stability are prepared by contacting alkaline faujasite or zeolite L with Pt- or Pd(acetylacetonate), to incor- porate 0.75-1.5 wt.% Pt and/or Pd into the pore surface regions of the zeolite, and calcining at 250-6OO0C. The products are used for reforming naphtha fractions, do not coke excessively at relatively low pressure, and can withstand feedstocks containing heavy hydrocarbons.

Three-Way Catalyst for Automotive Emission Control FORD MOTOR CO. U.S. Patent 4,992,405 A three-way catalyst with high conversion efficiency for CO, NOx and hydrocarbons consists of an Al,O, support having (discontinuous) La, 0, , 0.05-5.0 wt.% Pd, a 0.1-8.0 wt.% TiO, phase on the Pd/La,O,-Al,O, , and Rh at up to 10% wt. Pd on the Pd/La , 0 , -Ti0 , -Al , 0 , . The discontinuous crystallite deposits of TiO, and Pd/La ,O, interact to improve conversion efficiencies in lean exhaust gases.

Iridium-Iron-Titania Catalyst for Carbon Monoxide Oxidation PHILLIPS PETROLEUM co. U.S. Patent 4,994,247 A catalyst composition consists of 0.2-5 wt.% Ir, 0.2-5 wt.% Fe as Fe oxide, and TiO,, and is prepared by impregnating a TiO, support material with at least one Fe compound and at least one Ir car- bony1 compound, drying, and activating at 50-3OO0C with a reducing gas. The catalyst is used for oxidation of CO to CO, with free 0, at 20-30°C.

Palladium Catalyst for Decomposition of Organic Compounds

The organic phase resulting from oxidation of methyl benzyl alcohol to H,O, is contacted with a catalyst consisting of a noble metal supported on an Al , 0, containing carrier or Pd on Al,O,, to decompose organic compounds to a mixture of methyl benzyl alcohol and acetophenone, plus ethylbenzene. The methyl benzyl alcohol-acetophenone &Nre can be dehydrated to form a styrene monomer.

0.5-1.5 wt.% CO, 3-12 wt.% Mo, 2-10 wt.% CS,

ARC0 CHEM. TECHN. INC. U.S. Patent 4,994,625


Production of a-Methyl Benzyl Alcohol Using a Palladium Catalyst

a-Methyl benzyl alcohol is produced by hydrogenation of acetophenone by contact with H,, a Pd catalyst supported on C or Al,O,, and 1-5 wt.% H, 0, at 2O-5O0C and at least 5 psig in an organic solvent. Catalyst deactivation is substantially reduced by the presence of H,O and by the maintenance of H, pressure between batch runs. Conversion of acetophenone is more than 909'0, with more than 99% selectivity to the alcohol product.

Manufacture of High Purity Carbon Monoxide DAIREN CHEM. CORP. U.S. Patent 4,999,177 CO is produced by decarbonylation of methyl formate by heating at 15O-35O0C, in the presence of a catalyst of 0.02-5 wt.% of a Pt, Ir or Ru compound on a neutral or basic support, optionally with 0.1-10 wt.% of an alkali or alkaline earth metal compound as promoter. The catalysts used have high activity, long life, give high conversion of the methyl formate and a CO product with above 99 mol % purity.

Catalytic Hydrogenation of Benzene in Lower Alkane Feed UOP U.S. Patent 5,003,118 A feed containing 4-6C paraffins and at least 2 wt.% benzene is mixed with a Hz -rich gas stream, passed at 100-25OOF over a hydrogenation catalyst consisting of a support, a Pt group metal component and either Sn or Co and Mo to hydrogenate benzene, and contacting at 200-450OF with a catalyst to isomerise the 4-6C paraffins. Hydrocracking and loss of isoparaffin yield are prevented.

Surface-Enriched Platinum Isomerisation Catalyst UOP U.S. Patent 5,004,859 Hydrocarbons, especially 4-7C alkanes, are isomeris- ed by contact with a bed of catalyst particles consisting of a refractory inorganic oxide support, preferably Al,O,, 1-15 wt.% Al chloride, and a surface layer of 0.01-2 wt.% of a Pt group metal, preferably Pt. The reaction conditions are 40-25OoC and 1-100 atm, with an organic promoter such as CCl, present in the feed. The Octane number of a 5-6C naphtha stream is increased.

Rhodium or Ruthenium Catalyst for Steam Reforming of Hydrocarbons

Steam reforming of hydrocarbons is effected by supplying both components at 30O-95O0C and 0-50 kglcm'G to a catalyst layer having an upstream catalyst of 0.1-5 wt.% Rh or Ru on ZrO,, and a downstream catalyst of 7-20 wt.% Ni on a carrier such as Al 0 , . The catalyst has prolonged life, is cheaper, and enables steam reforming of the hydrocarbon at a low steam:carbon ratio.

ARC0 CHEM. TECH. INC. U.S. Patent 4,996,374

IDEMITSU KOSAN CO. LTD. Japanese Appl. 21302,304

Filter for Removing Harmful Gases DAIKIN KOGYO K.K. Japanese Appl. 314,922 The filter has a first fdter layer packed with active C, a second fdter layer packed with a Pd catalyst, and a third filter layer of urethane foam plate coated with particles and active C. The second layer has a supporting honeycomb frame with each compartment packed with Pd.supported on Al oxide spheres. The filter is used for cleaning air in a living space, by converting NO to NO, in the first layer and adsorbing, and oxidising CO to CO, in the second layer.

Selective Production of m-Hydroxy- benzaldehy de

A Pt andlor Pd type catalyst is used in the production of m-hydroxybenzaldehyde by oxidation of m- hydroxybenzyl alcohol with 0,, in an alkaline aqueous solution, using an alcohol and a tertiary ammonium salt to control formation of the by-product m-hydroxybenzoic acid. The product is formed with high selectivity (91%), and is a useful intermediate for perfumes, medicines and quantitative analysis of saccharides.

Production of Indoles Using Palladium Chloride KAWAKEN FINE CHEM. K. Japanese Appl. 3124,056 Indoles are produced by reacting 2-ethenylacetanilides with 1-100 mol % PdCl, in the presence of CuCl and an alcohol, at 40-80°C, in an 0, atmosphere, in a solvent. Indoles with substituents at positions 4, 5 , 6 or 7 can be produced in high purity and high yield, with the products useful as starting compounds for dyestuffs, perfumes,.drugs and agrochemicals, and particularly for alkaloids.

Ruthenium Hydrogenation Catalyst for Production of Alcohols MITSUBISHI KASEI CORP. Japanese Appl. 3127,335 Alcohols are produced by hydrogenation of carbonyl compounds at 15-15OoC, under normal pressure-100 kglcm,, in the presence of a Ru catalyst. The catalyst is prepared by impregnating an inorganic oxide carrier with a Ru compound such as Ru chloride, fixing with an alkali at 50-20O0C, and reducing. The catalyst is highly active, has a long working life, and produces alcohols which are useful as raw materials and high-performance solvents.

Diesel Exhaust Purification Catalyst

Waste gas is purified using a metal or ceramic honeycomb support loaded with 50-400 gA of refractory inorganic oxide of specific surface area 50-400 mz 19, and preferably also with Pt or Rh. The catalyst is used to remove C particulates containing the car- cinogenic soluble organic fraction (SOF) from diesel engine exhaust, and functions efficiently, even at low temperatures. The catalyst is regenerated by exposing to high temperature waste gas above 400OC.

MITSUI TOATSU CHEM. INC. Japatlese Appl. 3/20,238

NIPPON SHOKUBAI KAGAKU Japanese Appl. 3138,255


Palladium-Carbon Catalyst for Carbon Monoxide Removal KURARAY CHEMICAL K.K. Japanese Appl. 3142,038 A catalyst is prepared by thermally processing activated C in a N, and/or CO, gas containing no 0, andlor water vapour at > 5OO0C, cooling to < 3OO0C, and impregnating with 0.1-10 wt.% Pd chloride. The catalyst rapidly converts low concentrations of CO to CO, at room temperature, creating an atmosphere containing no CO.

Noble Metal-Lanthanum Aluminate Com- bustion Catalysts

Combustion catalysts consist of at least one of Pt or Pd supported on a LaAlO, coated fue resistant inorganic support such as Al,O, or mullite. The catalysts are fire resistant, can be used at temperatures < 1000°C for a long time period, and are used for purification of exhaust gases from automobiles or plant containing harmful components such as hydrocarbons.

Waste Gas Purification Catalysts with Separated Noble Metals TOKYO ROKI K.K. Japanese Appls. 3156,137-39 Waste gas purification catalysts consist of a catalyst support having a fmt coating layer of Al, 0 containing Rh andlor Pd, and a second coating layer of Ce oxide containing Pd, or Ce oxide containing Rh, optionally Pd and active Al, 0 , . The catalysts are inexpensive, show controlled heat deterioration, and depending on composition show either (a) improved NOx purification capacity, (b) improved low temperature activity with fluctuating &:fuel ratio, or (c) ability to remove CO and hydrocarbons even when the airhe1 ratio is rich.

Waste Gas Purification Catalyst with Improved Heat Resistance TOYOTA JIDOSHA K.K. Japanese Appl. 3156,140 A three-way catalyst used to remove NOx, CO and hydrocarbons from car exhaust consists of an inorganic support loaded with Pt, Pd or Rh, and Nb, Ta or W. The Nb, Ta or W forms a solid solution with Pt, Pd or Rh, and the higher melting point gives the catalyst improved heat resistance. In an example, an active AI,O, coated support was immersed in a solution of dinitrodiammine platinate, Pd chloride andlor Rh chloride, and Nb chloride, and dried.

Preparation of High Purity Isopropanol

Isopropanol is prepared by hydrogenation of acetone at 0-200°C under 0-50 kg/cm’G, using a supported Ru catalyst treated with bases. The catalyst is prepared by supporting 0.01-5 wt.% Ru metal on a carrier, especially active C, drying, treating with H, at 250-4OO0C for 3-24 h, and treating with alkali(ne earth) metal hydroxides or carbonates. High purity isopropanol is prepared under mild conditions.

BABCOCK-HITACHI K.K. JapaneSe Appl. 3152,642

MITSUBISHI PETROCH. K.K. Japanese Appl. 3156,428

Car Exhaust Purification Catalyst Free From Chlorine or Chloride TOY0 KOGYO K.K. Japanese Appl. 3160,737 An exhaust purification catalyst is produced by coating a slurry containing a precious metal chloride such as PtCI,, WCI, or RhCI, on a support, for example one coated with activated Al,O,, firing to deposit precious metal chloride, and passing water through to remove chlorine or chloride ions. As no chlorine or chloride ions remain in the catalyst, corrosive HCI is not discharged when high temperature car exhaust fumes are passed through it.

Hydrogenation Catalyst for Production of Chlorinated Aromatic Amines BAYER A.G. Gennan Appl. 3,928,329 Chlorinated aromatic amines are prepared by reaction of an aromatic nitro compound with H,, under pressure, at elevated temperature, in the presence of a solvent, a base, and a catalyst consisting of 0.3-7 wt.% F’t, and 1-100 wt.% (of Pt) of Ni and/or Coon an active C carrier.

Platinum-Indium Catalyst for Production of Pyrazine ZELINSKII ORG. CHEM. INST.

Russian Patent 1,558,910 Pyrazine is produced by dehydrogenation of piperazine vapour at 37O-40O0C in a H, or N, carrier gas, in the presence of a catalyst consisting of 0.4-0.6 wt.% Pt and 2-3 wt.% InO, on an Al,O1 support. The method gives an increased yield of pyrazine (70-76%), and simplified process conditions owing to use of the vapour.

Selective Palladium-Zeolite Hydrocracking Catalyst B. M. PAVLIKMIN Russian Patent 1,567,265 A catalyst used in the petroleum industry for isomerisation and selective hydrocracking of n o d paraffins has increased activity, higher selectivity for hydrocracking, and greater mechanical strength. The catalyst is prepared by peptisation of Al hydroxide, by treating an acid pseudo-sol with a zeolite containing 2% Pd, homogenising, ageing at 15-30°C for 2-24 h, forming into spheres, drying and calcining.

HOMOGENEOUS CATALYSIS Platinum Catalysed Curable Composition

A curable composition used in elastomers, composites, circuit boards, and so on, consists of a heterocyclic compound, a Si-H functional Si compound, and a Pt catalyst, and is prepared by mixing the components and preferably heating to 65-75OC. The Pt catalyst is used in small amounts and has a lower tendency to induce colour, oxidative instabili- ty, or corrosion to metals, and is less likely to destabilise the silicone polymer.

GENERAL ELECTRIC CO. European Appl. 415,243A


Preparation of Optically Active Aryl Propionic Acids for Medical Use RHONE-POULENC SANTE. Eumpean Appl. 419,312A Optically active 2-aryl propionic acids are prepared by reduction of a 2-aryl acrylic acid with H2 in an aqueous-organic medium, using a Rh catalyst with a chiral, water-soluble ligand. The Rh derivative is RhQ-(cycloocta-l,5-diene), or RhQ,, and the ligand is a sulphonated cyclobutane derivative, with a 1igand:Rh compound molar ratio of 1-100. The products are S-enantiomers of 2-aryl propionic acids, such as ketoprofen, naproxen, ibuprofen or profen, and have anti-inflammatory, analgesic andlor anti- pyretic properties.

Selective Hydrogenation of Imines Using Iridium Complexes CIBA GEIGY A.G. European Appl. 419,409A New Ir-diphosphine and Ir-diphosphinite complexes are used for hydrogenation of N-substituted imines to amines; catalysing the hydrogenation selectively without effecting hydrogenation of carbonyl, CN, NO, or C=C groups. The most important uses for the products are in the preparation of agrochemicals and pharmaceuticals, while some are biologically active substances, or are used as intermediates in their preparation.

Preparation of Haloamino Aromatic Derivatives

Haloamino aromatic derivatives are prepared at 70-150OC in an alcohol or aromatic solvent, by hydrogenation of a halonitro aromatic derivative with H2 using 1-20 gfl of a catalyst consisting of 0.1-1% of Pt or Pd on an AllOs support. The supported catalyst is easily recovered and recycled, can be used in a continuous process, and does not need pretreatment. &halogenation of the halonitm compound is avoided at 60-150OC.

Platinum Group Metal Additives for Fuels FUEL TECH. INC. World Appl. 91/1,36lA Internal combustion engine fuel such as gasoline, diesel fuel, CH,, C,H,, kerosene or jet fuel is catalysed by addition of a soluble Pd acetylene complex, Rh or Ir allyl complex, Pt(1V) compound or Rh or Ir compound, to give 0.1-1 ppm of a Pt group metal in the fuel. The additive is stable at lower temperatures, for example the storage temperature. The fuels bum more efficiently and with reduced harmful emissions.

RHONE-POULENC CHIM. European APPL 421,878A

Preparation of Nitriles Using a Nickel- Palladium-Phosphine Catalyst NIHON NOYAKU K.K. Japanese Appl. 3114,554 Nitriles are prepared by reaction of organochlorine compounds with alkali metal cyanides in the presence of alkali metal halides and a catalyst consisting of Pd compounds, Ni compounds and phosphines, by heating at 100-250OC for 1-48 h, in an inert solvent.

Preparation of Unsaturated Organic Silicon Compounds TOSHIBA SILICONE K.K. Japanese Appl. 3114,590 New organic Si compounds having an unsaturated group are prepared by reaction of 1 mol of divinylbenzene with 0.4-1.0 mol of a silane such as trichlorosilane, at -30 to 15OoC, in the presence of a Pd catalyst such as dichlorobis(tripheny1phosphine)- Pd(I1). The products have a highly reactive double bond, and are useful as silane coupling agents, modifiers for organic resins, crosslinkers, and so on.

Preparation of a-Amino Acid Derivatives AJINOMOTO K.K. Japanese Appl. 3131,245 Hydroxy-N-acyl-a-amino acid derivatives are produced by reaction of 2-butene-1,Cdiol with CO and an acid amide at 50-2OO0C, under 10-500 atm pressure, in the presence of a CO catalyst and a Pd or Rh catalyst. The Pd catalyst includes PdCl,(PPh,),, and the Rh catalyst HRh(CO)(PPh,), . The products are made from a cheap raw material by this simple and selective process, and are used as physiologically active compounds with enzyme-inhibiting actions, or intermediates.

Palladium Oxidation Catalyst for Preparation of Dimethylbutanone SUMITOMO CHEM. IND. K.K. Japanese Appl. 3163,241 3,3-Dimethyl-2-butanone is prepared by oxidation of 3,3-dimethyl-l-butene with O,, in an alcohol solvent, at O-15O0C, under 0-100 kglcm2, and in the presence of a catalyst consisting of a Pd compound, a heteropolyacid, and optionally Cu compounds. The product is separated from the reaction mixture, and the residue re-used as catalyst solution. The product is prepared in high yield, for a long time, by using an alcohol as solvent.

FUEL CELLS Platinum-Ruthenium Fuel Cell Electrode Catalyst MATSUSHITA ELEC.1ND.K.K. Japanese Appl. 3122,361

Onemstep Of using A catalyst used for the electrode of a liquid fuel cell consists of highly dispersed Pt and Ru on fine C par- a Palladium Catalyst

IOWA STATE W V . RES. INC. U.S. Patent 4,992,568 ticles. The Pt catalyst consists of the complex oxide A one-step synthesis of benzofurans is effected by cyclising an orthoiodoaryl allyl ether at 60-120°C, in the presence of a Pd catalyst, a polar solvent, and a base, to yield a 3-substituted furan. The benzofuran products are obtained in high yields.

of at least two of go, PtO, and PtO ads.,. while the Ru catalyst consists of at least one of RuO, and RuO,, with a Ru:R atomic ratio of 1-2. A safe fuel cell catalyst can be easily prepared, giving a fuel electrode with improved efficiency.


One-Step Synthesis of Benzofurans Using a Palladium Catalyst IOWA STATE UNIV. RES. INC. U.S. Patent 4,992,568

CORROSION PROTECTION High Temperature Slag-Resistant Thermocouple Sheath TEXACO INC. U.S. Patent 5,005,986 A metal sheath for a Pt/Rh thermocouple consists of a continuous binary alloy of 30-70 wt.% Pd and balance Ag. The sheath protects the thermocouple from Fe, V, and so on in the slag, and its porosity to H, prevents any corrosive V(V) oxide from forming. The sheath is useful in high temperature systems for forming fuel gas, synthesis gas and reducing gas, and thermocouple lifetime is prolonged and temperature measurements are more accurate. The thermocouple may be used in the temperature range 1000-2400°F.

Long-Life, High Density Cathode for Microwave Devices U.S. SEC. OF THE ARMY U.S. Patent 5,007,874 The cathode consists of W and Ir powders impregnated with the reaction product of a Group IIIA metal powder and BaO, in a 2:3 molar ratio. Specifically the cathode can contain 61 wt.% W, 38 wt.% Ir, 1 wt.% Zr hydride activator, Al powder and BaO,. The W-Ir cathode is used in microwave devices, and has long life, high density, can be prepared by a rapid and direct method, and uses a lower temperature in forming the impregnant.

Thick Film Resistor Composition Containing Ruthenium SUMITOMO METAL MINI K.K. Japanese Appl. 319,501

ELECTRICAL AND ELECTRONIC ENGINEERING

A composition for forming a thick film resistor consists of 10-50 wt.% of glass powder containing 35-70 wt.% of PbO. 15-40 wt.% SO,. 5-40 wt.% of at

Stable Superconductor with Noble Metal Layers FURUKAWA ELECTRIC CO. European Appl. 401,461A A superconductor combining high electromagnetic stability with high mechanical strength is an alter- nating laminate of oxide superconductor layers and discontinuous metallic layers, preferably in a concen- tric, spiral or plate-like form, and may also include layers of a high strength, heat resistant metal. The oxide superconductor is for example La,,Ba,CuO, , and the metallic layers are Pt, Pt-Pd, Pt-Ir, Pd, Pd- Ni, Pd-Co, Au, Ag, certain alloys of Au or Ag, or others.

Thin Film Cobalt Platinum Alloy Magnetic Recording Disc IBM CORP. European Appl. 413,423A A thin film Copt alloy magnetic disc has a magnetic recording layer, preferably containing 5-30 at.% 0, and a non-magnetic Cr under-layer. The oxygen is introduced into Ar during the sputter deposition of the Copt alloy magnetic layer on the disc, which is then heat treated to improve further the recording layer. The resulting disc structure has substantially less intrinsic media noise at high linear recording density than comparable disc structures.

Cobalt-Platinum Thin Film Magnetic Recording Media KOMAG INC. U.S.Patents 4,749,459 and 4,988,578 Thin film magnetic recording media consist of an alloy of Co and Pt sputtered on a substrate from a controlled atmosphere to give an alloy having an intrinsic coercivity of 600-2000 &, preferably > 650 Oe. The films may be doped with N, and/or 0, , with the N2 concentration in the fdm preferably < 1 mol YO. The thin fdm magnetic recording media can be prepared with controlled coercivity without affecting other important parameters such as the saturation magnetisation and so on, and without changing the sputtering target.

L ,

least one of duo,, Pb,Ru,O,-, and Bi,Ru,O, --x, 20-40 wt.% of organic vehicle, and 0.2-5.0 wt.% of B , 0, powder. A preferred composition also contains 20-60 wt.% of one or both of Pd and Ag. The composition is used for forming a thick film resistor on a ceramic substrate, and has reduced resistance change on repeated heating.

High Density Magnetic Recording Medium HITACHI K.K. Japanese Appl. 3/16,013 A magnetic recording medium has a non-magnetic substrate, a non-magnetic underlayer containing Cr, and a magnetic layer containing an alloy of 1-35 at.% Pt (Ir), 1-17 at.% Cr and Co, and 0.1-10 at.% 0. In an example the magnetic layer was 10-90 nm thick and consisted of (3-15 at.% Cr-11 at.% Pt-3 at.% 0. The magnetic recording medium has high density, corrosion resistance, abrasion resistance and large capacity.

Resistant Paste for Use on a Circuit Substrate TDK COW. Japanese Appl. 3118,089 A resistant paste consists of glass frit, conductive particles containing Pb ruthenate and/or Ru oxide, and Bi ruthenate, and a vehicle. A thick film resistant layer is made by baking the resistant paste, and a circuit substrate is made by laminating a conductive paste and the resistant paste on a substrate, then baking at up to 1000°C. The paste gives improved productivity and yield, and fewer process steps.

Multilayer Strontium Titanate Ceramic Element MARUWA CERAMIC K.K. Japanese Appl. 3144,020 A multilayer ceramic element is made by laminating a material containing SrTiO, as a ceramic layer, and a paste containing Pd as an internal electrode, fring in a reducing atmosphere at 1160-1220OC to impart semiconductivity and density, followed by treating in an oxidising atmosphere at 1000-1200°C.


TEMPERATURE MEASUREMENT Temperature Detecting Circuit for a Platinum Temperature Sensor MURATA MFG. W. Japanese Appl. 3113,830 A temperature detecting circuit for a Pt temperature sensor includes a bridge circuit formed in combination with the Pt temperature sensor, an electric source, a differential amplifier, and positive and negative feedback loops. The temperature detecting circuit has simple structure, giving linear temperature-output characteristics for the Pt sensor.

Temperature Sensor Containing Finely Dispersed Platinum HAFELE UMWELTVERFAH G e m n Appl. 3,924,518 A temperature sensor has a layer of oxides and 60-90 wt.% fmely dispersed Pt deposited on a ceramic substrate. The oxides are preferably 45-50 wt.% Si oxide, 30-35 wt.% Al oxide and 18-20 wt.% of an alkaline earth oxide, preferably Ca oxide, and the temperature sensitive layer is fved after deposition to give a compact glassy morphology. The sensor can be used at 600-120O0C; is sensitive and stable.

New Palladium Complexes for Use as Anti-Tumour Agents TSUMURA & CO. Japanese Appl. 21311,488 New bis(dipheny1phosphho)ethane Pd complexes have good water solubility and are prepared from cyclohexanediamine Pd(I1) nitrate compound or 1,2-bis(diphenylphosphino)ethane Pd(I1) chloride, in water. The complexes are used as anti-tumour agents, and can be administered orally, parenterally or rectal- ly at a daily dose of 1-600 mg for adults.

Anti-Bacterial Resin Compositions TORAY IND. INC. Japanese Appl. 3143,456 A resin composition contains 0.1-20 wt.% of at least one of Pt, Au, Ag, Cu or Zn ions, and 0.01-20 wt.% of a hydrated metal oxide of average grain diameter up to 10 pm, for example antimonic acid. The hydrated metal oxide has anti-bacterial properties, and good moulding properties are obtained.

New Doxorubicin Platinum Co-ordination Compounds as Anti-Tumour Agents

New 1: 1 chelated doxorubicin Pt co-ordination compounds are obtained by reacting doxorubicin hydrochloride and K or Na tetra- or hexa- chloroplatinate. In the compounds doxorubicin (adriamycin) and Pt(1I) or Pt(IV) are 1:l chelated. The compounds are used as anti-tumour agents.

Adhesive Waterproof Sheet for Medical Use EARTH SEIYAKU K.K. Japanese Appl. 3/75,055 A sheet for medical use consists of an adhesive hydrophobic hardened f h formed on a substrate. The f h is formed by hardening organopolysilox- ane(s), organopolyhydrodiene siloxane(s), and 0.1-300 ppm of one or more of Pt, Pd and Rh catalysts. Applied to gauze or an emergency plaster the sheet prevents water permeation and infection, is flexible and expansible, does not need replacing after bathing, and has high adhesion to the skin, allowing re-use.

New Anti-Neoplaemic Tetravalent Platinum Complex MOSCOW LOMONOSOV UNIV. Russian Patent 1,557,106 cis-Diamminedichlorodihydroxy Pt(rv) sulphate of the formula (Pt(NH,Cl),OH.H,O).HSO,.xH,O, where x is 0-2, is prepared from Pt(NH, Cl) , (OH) , and H, SO,. The compound has increased efficiency as a drug for treatment of neoplasms due to the presence of the OH.H,O bridging ligand with its symmetrical arrangement -0H.H.OH- and formation of H bonds between the HSO, ions and the NH, groups. The compound shows reduced toxicity, of LD5O Smgkg body weight.

MORISHITA PKARM. K.K. Japanese 3168,595

MEDICAL USES New Bis-Platinum Complexes Used for Radiation Sensitisation UNIV. VERMONT STATE World Appl. 9113,482A New bis-Pt complexes contain primary amine N atoms co-ordinated to the Pt atom in such a way that the Pt is present as Pt , + . The complexes are used in the treatment of tumours, for radiation sensitisation or potentiation, and to treat parasitic diseases such as sleeping sickness. The complexes are used at the same dosage as cisplatin.

Test Papers for Detecting Abuse-Type Drugs J.J. GIBSON U.S. Patent 4,992,296 The presence of drugs such as amphetamines, co- caine, marijuana and morphine-like compounds may be detected rapidly at low concentrations, especially in urine, using test papers. These are prepared by (a) contacting a bibulous cellulose carrier with a dilute HCl solution of a Pt salt and an I salt, and drying, or (b) immersing a bibulous paper sheet in dilute HCl solutions of iodochloroplatinate, and Bi subnitrate and iodochloroplatinate, and drying.

New Cyclohexanediamine Platinum Complexes as Anti-Tumour Agents WARNER-LILMBmT CO. US. Patent 4,999,444 New natural ligand Pt(1I) complexes or acid addition salts are used in the treatment of malignant neoplasms, tumours, and also leukemia, and the compound SP-4,2-(cis)-dich-(1,4-cyclohexanediamine-N,N’)Pt is specifically claimed.

The New Patents abstracts have been prepared from material published by Dement Publications Limited,


AUTHOR INDEX TO VOLUME 35 Page

Aballe, M. 33 Aboul-Gheit, A. K. 107 Abys, J. A. 157, 165, 208 Achi, S. 161 Ackelid, U. 234 Adams, D. M. 229 Adams, R. D. 156 Adeva, P. 33 Adhya, S. K. 237 Aganov, I. A. 34 Agapov, I. A. 103 Aggarwal, I. D. 164 Ahn, B.-T. 158 Akomolafe, T. 240 Aldaz, A. 34 Alper, H. 162, 237 Alphine, S. 82, 105 Al-Shammary, A. F. Y.

160 Amadelli, R. 37 Amano, M. 32 Amariglio, A. 195 Amariglio, H. 195 An, L.-D. 108 Anders, K. 107 Anderson, J. A. 159 Anderson, M. A. 235 Anderson, W. A. 46, 113 Anderson, W. K. 46 Anderson, T. 234 Ando, H. 164 Ando, M. 230 Anton, R. 154 Antonov, P. G. 34, 103 Aoki, T. 165 Araki, Y. 153 Aramendia, M. A. 159 Arcadi, A. 238 Arena, C. G. 239

Artem’ev, M. V. 36 Asakura, K. 42

Asano, T. 240 Asanuma, H. 40 Ashton, S. V. 137, 208 Astakhov, I. I. 103 Awasthi, A. K. 238 Ayestaran, J. 237 Ayyagari, S. 208 Azuma, M. 37

Argazzi, R. 37

Asami, K. 157

Baba, K. Babenko, V. P. Bae, I. T. Backvall, J.-E. Baena, M. J. Bag, N. Bai, X. Baiker, A. Bain, A. C. Bakker, J. W.

33 230 232

163, 239 23 1

34, 45 160 107 237 155

Page Balakrishnan, K. 107 Baldwin, T. R. 108

Ballester Reventos, L. 156 Ballinger, T. H. 140 Balzani, V. 104, 105 Bar, G. 234 Baralt, E. 104 Barbero, C. 113 Barchewitz, R. 39 Barrault, J. 109 Basili, N. 154 Basset, J.-M. 112 Basu, P. 45 Baturin, G. 23 Baur, E. 236 Beard, B. C. 103 Beery, J. G. 240 Behm, R. J. 230 Bekheit, M. M. 231

Belgued, M. 195 Beltrarnini, J. N. 39, 235

Ballardini, R. 104

Wlanger, G. 35

Belyakov, G. P. 35 Benner, L. S. 93

Bergens, S. H. 111

Berenblyum, A. S. 40 Berents, A. D. 159

Bergveld, P. 137 Bernik, S. 155 Berthier, Y. 152, 159 Besnier, I. 161 Bhaduri, S. 45 Bianchi, M. 163 Bickle, G. M. 39 Bignozzi, C. A. 37 Birss, V. I. 102 Bittar, A. 110 Biwas, P. C. 232 Blanco, C. 41 Blanpain, B. 32 Blaser, H . 4 . 39 Blee, J. 208 Bodnhr, Z. 108 Bogatskaya, T. G. 35 Bogdanovic, B. 229 Boher, P. 39 Bonneviot, L. 235 Boodts, J. F. C. 104 Borau, V. 159 Borgesen, P. 33 Borisov, A. 0. 158 Boronin, A. I. 160 Bos, M. 137 Bosnich, B. 111 Bouas-Laurent, G. 104 Bouillon, F. 155 Boujana, S. 159 Boutrouille, P. 102 Bower, R. W. 235 Brandes, B. D. 1 1 1 Brandt, M. D. 106 Branitskii, G. A. 36

Page Braunstein, P. 10 Brearley, W. H. 229 Breault, R. 109 Bressan, M. 45 Briones, F. 45, 106, 200 Briot, P. 108 Brisse-Le Menn, F.

162. 239 Brookhart, M. I62 Brucker, C. F. 155 Bruno, J. W. 37 Buchanan, B. E. 105 Eucur, R. V. 138 Burch, R. 108 Burgess, K. 238 Burgio, N. 154, 230 Burke, L. D. 1 02 Burkett, H. D. 40, 155 Bush, R. P. 202 Butt, J. B. 40, 41 Buxbaum, A. 229

Cacchi, S. 238 Caga, I. T. 160 Calderazzo, F. 237 Calle, A. 106, 200 Campagna, S. 105

Caram, J. A. 38, 232 Carcia, P. F.

31, 112, 228

Canepa, F. 34

Carl, A. 101 Carol, L. A. 34 Carter, C. B. 112 Caruana, G. 33 Casillas, N. 234 Caulton, K. G. 37 Cavell, K. J. 106 Cazes, B. 44 Chakravorty, A. 34, 45 Chambellan, A. 109 Chan, A. S. C. 162 Chan, C. 110 Chattopadhyay, S. 45 Chebaeva, 0. V. 159 Chen, C. K. 164 Chen, C.-L. 155 Chen, F. L. 33 Chen, L. 35 Chen, S.-Y. 39 Chen, Y. 39, 160 Chen, Y.-J. 38 Cheng, C.-H. 238 Chin, V. W. L. 164, 228 Chiou, B.-S. 165 Chocron, S. 233 Choi, K. I. 109 Chojnacki, T. 108 Chou, C. H. 38 Chou, T. C. 153 Choudhury, S. B. 34 Choung, S. J. 40

Page Chowdhury, R. 163, 239 Christofides, C. 234 Chu, S. N. G. 46 Chu, Y.-Z. 42 Chuvilin, A. L. 237 Ciano, M. 105 Ciattini, P. G. 161 Cider, L. 107, 236 Clayton, T. W. 162 Coche, L. 103 Colchero, J. 229 Colebrook, R. 102 Coleman, J. P. I62 Collins, F. M. 113 Comninellis, Ch. 95, 105,

157, 232 Consiglio, G. 161 Contardi, V. 154 Coombes, J. S. 132, 137 Cooper, B. J. I78 Cooper, J. B. 233

Cornet, D. 109 Corti, C. W. 133 Cottington, I. E.

21, 23, 27, 31, 64, 82, 85, 93, 95, 132, 137, 141, 195, 201, 208, 222

Cowie, J. G. 228 Crabtree, R. H. 44 Cramer, E. 43 Crisafulli, C. 40 Crowell, J. E. 109 Culbertson, R. J. 228 Cusumano, M. 23 I

Coq, B. I10

Dai, C. H. 40 Dai, H. 33 Dalbay, N. 103 Dannetun, H. 235 Darwell, J. E. 109 Dasaeva, G. S. 43 Datta, R. 235 Dautremont-Smith,

w. c. 46 Davies, D. J. 20 1 Davies, J. A. 35 Davies, S. G. I02 Davis, B. H. 39 Davis, M. 42 Davis, M. E. 42 Davydov, A. D. 103 De Giovani, W. F. 11 1 De La Torre, A. 33 De Martin, S. 44 De Oliveira, 1. M. F. 36 De Reus, R. 46 Deckers, S. 101 Dell’Amico, D. B. 237 Delmastro, M. 238 Delogu, G. 44 Delplancke, M. P. 155


Dema, A. C. Den Hartog, A. J. Deng, D. Deng, M. Deng, Y. J. Deng, Y. Q. Denti, G. Desvergne, J. P. Diver, R. B. Dmitriev, V. Do, D. D. Do, H. Doblin, C. Dobrzynski, L. Dolcetti, G. Donato, A. 40, Doyle, M. L. Doyle, M. P. 11 1, Du, J. Du, Z. Dubbe, A.

Dumpich, G . Dutartre, R. Dutta, D. R. hhunusov, A. K.

Duh, J.4.

Page

Eagle, C. T. Ebina, K. Efstathiou, A. M. Ehui, B. Euenberg, M. El Fallah, J. Elewady, Y. A. Elsevier, C. J. El-Morsi, A. K. Enami, E. England, C. D. Ennas, G. 154, Enyo, M. Epa, W. R. Espinet, P. Espin6s, J. P. Esteruelas, M. A. Evetts, J. E. Ewen, R. J.

Fache, E. Falco, C. M. Faraone, F. Faraone, L. Farebrother, M. Farooque, M. Farrar, D. H. Fasman, A. B. Fathauer, R. W. Feldhaus, R. Feldman, J. Feng, L. Fenoglio, R. J. Fenske, D. Ferro, R. Ferroud, D. Ficarra, P.

42 159 32

159 158 108 105 104 37

196 39

152 159 229 41

236 83

162 160 160 158 165 101 110 237 108

111 101 237 103 229 159 23 1 161 107 157 101 230 232 238 23 1 41

162 234 160

112 101 239 165 102 112 156 108 32

107 109 104 41

156 154 161 231

Page Ficarra, R. 23 1 Figueras, F. 110 Fischel, L. B. 40 Fish, J. D. 37 Flanagan, T. B. 33 Folkers, J. P. 236 Fortunato, G. 85 Fox, M. A. 35 Friant-Costantini, A.

82, 105 Fritz, H. P. 111 Fryberger, T. B. 106 Fujii, K. 240 Fujii, Y. 157 Fujikawa, K. 233 Fujimori, H. 33 Fukada, S. 113 Fukuda, T. 156 Fukutomi, M. 240 Furukawa, M. 33 Furuya, N. 164, 228

Gabriel, C. J. 233

Galicia, L. 232 Galvagno, S. 40, 236 Gandolfi, M. T. 104

Gardner, S. D. 107 Garin, J. 237 Garland, M. 39, 107 Garrait, M. 37 Gates, B. C. 237 Gatotskii, V. S. 232 Gavrilov, K. N. 239 Geiger, J. F. 158 Gellmann, A. J. 236 Genet, J. P. 111, 161 Gerkema, E. 229 Geus, J. W. 101 Ghorai, D. K. 237 Giannetto, A. 23 1 Gladiali, S. 44, 239 Gland, J. L. 155 Glumov, M. V. 102 Giipel, w. 158 Giirtzen, A. 33 Goldman, A. S. 239 Goledzinowski, M. 102 Golmayo, D. 106, 200 Golodets, G. I. 237 Gonzalez, I. 232 Godez-Elipe, A. R. 41 Goodenough, J. B. 103 Goodwin, H. A. 102 Goodwin, J. G. 42 Gorshkova, L. S. 239 Goupil, J. M. 109 Griitzel, M. 37 Graham, G. W. 101 Graifer, A. Yu. 105 Graziani, M. 41

Grifith, W. P. 3 I , 45 Grigg, R. 161

Gafney, H. D. 37

Gao, Y.-Q. 21

Green, M. A. 37

Page Grigoryan, E. A. 158 Grushin, V. V. 162 Giintherodt, G. 101 Gukathasan, R. R. 156 Gulari, E. 152 Gusevskaya, E. V.

43, 160 Gutihez, C. 38, 232 Gutierrez-Alonso, A. 156

Haas, 0. 113 Haasnoot, J. G. 105 Habraken, F. H. P. 101 Haen, P. I02 Hage, R. 105 Hagi, H. 103 Hahm, H. S. 41 Haller, G. L. 235 Halligudi, S. B. 237 Han, C. C. 165 Han, Y. 23 1 Hanan, G. S. 23 1 Hanson, B. E. 42 Hapiot, P. 105 Harano, H. 33 Haraya, K. 27 Hards, G. A. 17 Harnsberger, S. K. 35 Harriman, A. 22, 105 Harris, D. W. 46 Haruki, M. 153 Harzer, J. V. 101 Hasegawa, F. 240 Hasbimoto, K. 36, 157,

236 Hashimoto, M. 152 Hashimoto, S. 3 I , 32 Hasan, M. E. 160 Hatfield, W. E. 37 Haugwitz, R. D. 46 Hayashi, N. 228 Hayashi, T. 238 Hay-Motherwell, R. 5.34 Hazama, M. 162, 239 He, P. 152 Heath, A. E. 229 Hendriks, H. E. J. 40 Herrero, J. Hettrick, C. M. Heuer, L. Hey, J. A. Hicks, R. F. High, K. G. Highmore, R. J. Hilaire, L. Hillebrands, B. Himeda, T. Hinden, J. Hinohara, K. Hirai, T. Hiramoto, M. Hodges, A. M. Hoffman, B. M. Hoflund, G. B. Hogan, R. E.

41 238 86

106 38. 40

162 234 109 101 230 157 165 36 36

106 156 107 37

Page Honeybourne, C. L. Hong, Q. Z. Horner, B. T. Houdy, P. House, D. A. Houston, D. M. Howe, J. M. Hrovat, M. Hsu, W. P. Huang, Y. Huang, Y . 4 . Hubert, A. J. Huffman, J. C. Hughes, H. Hursthouse, M. B. Hussain-Bates, B. Huusko, J.

160 112 58 39 38 46

229 155 34

237 155 23 1 37 I05 34 34

235

Ibers, J. A. Ikariyama, Y. Ikefuji, Y. Ishino, M. Ismail, M. S. Itaya, K. Itoh, N. Ivanova, L. S. hey, D. G. Iwanaga, Y. Iwasawa, Y. Izawa, K. Izumi, Y.

I56 165 110

162. 239 235 228 27 35

153 157 42 36 43

Jacobson, D. L. 230 Jacques, R. 35 Jaganathan, J. 164 Jagielinski, T. M. 155 Jain, V. 240 James, E. B. 228 Jardinier-Offergeld, M.

155 Jarstfer, M. B. I l l Jayakrishnan, S. 106 Jebaratnam, D. J. 110 Jenner, G. 163. 239 Jewell, J. M. 164 Jhans, H. 229 Jia, Q. X. 1 I3 Jian, P. 153

Jiao, K. L. 46, 113 Jimhez, C. 159 Jin, L. Y. 159 Jin, Z. 104 Johnson, H. H. 33 Jolliffe, J. M. 45

Jones, M. G. 160

Jiang, Z. 110

Jona, F. 230

Jones, W. D. 156 Jongerius, F. I59 Joshi, A. 153 Josso, P. 82, 105 Joyal, C. L. M. 41 Juge, S. 111, 161 Jung, W . 4 . 154


Page

Kadija, I. 165, 208 Kadirgan, F. 103 Kadish, K. M. 158 Kaesz, H. D. 38, 112 Kagiya, T. 36 Kaikati, P. 39 Kamalov, G . L. 237 Kamer, P. C. J. 239 Kanamaru, K. 38 Kanaya, H. 240 Kaneko, M. 158 Karandin, A. V. 43, 160 Kardos, N. 161 Karlsson, U. 163 Kashihara, H. 236 Kaslinal, R. 46 Kdpar , J. 41 Katakura, K. 38, 158 Kataoka, M. 33 Katayama, T. 152 Kato, A. 2 30 Kato, H. 113 Katz, A. 46 Kawakita, c. 165 Kawami, Y. 35 K a w a s h i , A. 157 K a w a s h i i , I. 153 Kawata, H. 2 30 Kawi, S. 237 Kazakov, V. P. 233 Kazala, A P. 111 Kazarinov, V. E. 103 Kelly, E. J. 36 Kelm, M. 33 Kenjo, T. 233 Kennedy, B. J. 36 Keppler, B. K. 46 Ketterling, A. A. 43 Khannanov, N. K. 158 Khodkevich, S. D. 35 Kickham, J. E. 231 Kiennemann, A. 109, 159 Kiiiski. U. 110 Kikuchi, E. 38, 154, 164 Kim, J. Y. 33 Kim, Y. K. 38 Kimura, K. 229 Kimura, M. 233 Kira, A. 158 Kirner, U. K. 158 Kiseleva, I. G. 103 Kita, H. 102 Kitada, M. 23 1 Klabunovskii, E. I. 44,

239 Kleppa, 0. J. 154 Kleykamp, H. 33 KiSber, J. 106 Knoch, F. 232 Knozinger, H. 109 KO, D.-H. 153 Kobayashi, H. 104 Kobayashi, T. 1 65 Kochetkova, E. A. 158 Kochubey, D. I. 230

Kaburagi, M. 101 Page

Koelle, U. 36 Kotz, R. 113 Kolar, D. 155 Kolawa, E. 1 I3 Komaki, M. 32 Komori, K. 240 Kondo, T. I l l KO%, K.-C. 238 Kooh, A. B. 40 Koper, R. J. 1. M. 46 Koroshkov, Yu. D. 44 Koshcbeev, A. P. 105 Kosik, W. E. 228 Kosonocky, W. F. 208 Koubuchi, Y. 1 I3 Kourov, N. I. 228 Krause, K. 108 Krause, 0. 110 Kron, T. E. 238 Kudrak, E. J. 165, 208 Kudryavtsev, D. Yu. 103 Kuecb, T. F. 165 Kuhrt, C. 154 Kukushkin, Yu. N. 28 Kumagai, Y. 240 Kumai, T. 112, 240 Kumar Lahiri, G. 45 Kunjappu, J. T. 37 Kunugi, A. 35 Kuo, K. H. 21 Kush, A. 112 Kuster, B. F. M. 40 Kuykendall, V. L. 156 Kwaskowska-Chec, E.

156

Laffrtte, J. A. 111 Lahiri, G. K. 34 Laibinis, P. E. 236 Langenbahn, M. 163 Lantto, V. 235 Lapidus, A. L. 42 Larock, R. C. 43, 237 Larpent, C. 162, 239 Lau, s. s. 165 Lautens, M. 110 Le Normand, F. 109, 159 Lechner, P. 232 Lechuga, L. M. 106, 200 Lee, c. w. Lee, D.-B. Lee, J. S. Lee, R. Y. Lee, S. M. Lee, W. H. Lee, w. Y. Leech, D. Leglise, J. Lei, J.-F. Lejay, P. Leonard, S. Lewis, F. A. Lewis, L. N. Lewis, N. Ley, s. v.

238 133 238 153 238 101 41

106 109 65

102 229

138, 153 110. 238 110, 238

45

Li, H. Li, Q. Li. W.

Page 230 104 39

Li; Y. 33 Li, Y. S. 230 Li, Y.-X. 39 Libs-Konrath, S. 163 Lii, J.-C. 156 Likholobov, V. A.

43, 160, 237 Lilienfeld, D. A. 33 Limosin, D. 103 Lin, J. 162 Lin, S.4 . 155 Linton, M. 106 Lisitsyn, A. S. 43, 109 Liska, P. 37 Liu, C. C. 232 Liu, J. C. 32 Liu, K. C. 165 Lwb, S. J. 231 Laffler, D. G. 160 Logan, R. A. 46 LOU, H.-Y. 42 Lovering, D. G. 209 Lowder, L. J. 228 Loxton, C. M. 101 Lu, G. 109 Lu, Y.-D. 237 Ludwig, M. 106 Lukehart, C. M. 42, 104 Lundstriim, I. 235 Lunniss, J. A. 156 Lutsko, T. P. 34 Lyukke, B. 42

Ma, L. 21 MacDonald, J. 112 Maclay, G . J. 32 Maeda, H. 240 Magini, M. 154, 230 Maguire, J. A. 239

Maisano, J. J. 165 Makhaev, V. D. 158 Maksiiov, M. N. 103 Mallart, S. 111 Mall&, T. 108 Mandelis, A. 234 Manek, Kh. E. 42 Mann, G. S. 34 Manoharan, R. 103 Marazza, R. I54 Marin, G. B. 40 Marinas, J. M. 159 Marinella, F. 238 Mariucci, L. 85 Martelli, S. 154, 230 Marti, 0. 229 Maru, H. 112 Maruyama, T. 233 Masel, R. I. 101 Masuda, T. 236 Matbews, J. F. 159 Matijevif, E. 34

Maher, E. F. 2

Matsubara, S. Matsuda, M. Matsuda, T. 38, Matsuda, Y. Matsui, H. Matsui, T. Matsumoto, K. Matsuo, T. Matsuya, S. Matteoli, U. 42, Mau, A. W . 4 . Mayer, J. W. 32, McAndrew, J. McBride, J. R. McDaniel, T. McGaban, W. A. McGhee, E. M. McGhie, A. J. McNicboll, R.-A. McPhail, A. T. McPhail, D. R. Meas, Y. Meguro, K. Melendez, E. Melngailis, J. Menchi, G. Menchikova, G. N. Menoufy, M. F. Merchan, F. L. Mermoud, F. Mestroni, G. Miao, H. J. Michenfelder, A. Michman, M. Mignot, J.-M. Mikhailenko, S. D. Mikhailova, L. A. Miller, B. Miller, S. E. Mills, P. L. Mine, K. Misra, D. Mitchell, G. E. Mitchenko, S. A. Mitsudo, T.-A. Miura, N. Miyagawa, U. Miyamoto, K. Miyasaka, Y. Miyashita, T. Mizuno, F. Mlynek, J. Mochida, I. Mobius, R. Moiseev, I. I. 43, Moll, M. Molle, W. Mwney, J. M. MorallBn, E. Morera, E. Moret, M. Moriarty, R. M. Moribe, S. Morii, K. Morita, M. Moroz, B. L.

Puge I12 233 I54 157 35

228 43

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232 93

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Page Moroz, E. M. 108. I60 Morten, B. 240 Morvillo, A. 45 Moser, J. 37 Mostafa, S. I. 231 Motone, M. 35 Moutet, J.-C. 36, 103 Mu, X. H. 158 Miiller, H.-J. 38 Mueller, T. I10 Mukai, T. I l l Mukaiyama, T. I I 1 Mukesh, D. 45 Muller, G. I10 Mundschau, M. 188 Mustazza, C. 41 Myasnikov, I. A. 105

Nagai, R. 165 Nagamura, T. 234 Nagao, M. I63 Nagaoka, Y. I54 Nagashima, K. 230 Nageswara Rao, N. 104 Nahme, E. M. 163 Nahor, G. S. 105 Nakagawa, M. 46 Nakajima, H. I63 Nakatani, R. 23 I Nakato, Y. 104 Nakayama, Y. 228 Nanao, S. 230 Nannichi, Y. 240 Nara, K. I13 Naravanan. V. L. 46

Page Nishimura, C. 32 Nishimura, K. 157 Nixon, B. 152 Noels, A. F. 231 Noma, A. 38, 158 Nomura, K. 162, 239 Noreus, D. 229 Norman, A. 229 Norton, P. R. 152 Noskov, Yu. G. 161

Notton, J. H. F. 16 NovPk, I?. 41 Novak, Z. 42 Novikov, N. A. 161 Nowak, R. J. 233 Nowroozi-Esfahani, R. 32 Nuiiez, G. M. 41

Nosov, A. V. 43

Ochiai, Y. Ogryz’ko-Zhukoi

S. G. Ogumi, Z. Oguri, K. Oh, J. S. Oh, S. H. Ohlmeyer, M. J. Ohlsson, B. Ohmori, T. Ohno, H. Ohta, M. Ohta, T. Ohtani, B. Ohzuku, T. Okaii. M.

31

35 38. 158

33 238 41

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rskaya,

Page Patin, H. 162, 239 Patzer, J. F. 35 Paul, B. C. 163 Paul, D. K. 108, 109 Pavlov, V. A. 44, 239 Pavlyukevich, L. V. 108 Pecora, A. 85 Peng, SPY. 39 Pentinghaus, €I. 33 Percec, V. 43 Persau, C. 156 Peters, C. R. 101 Peterson, L.-G. 234, 235 Pethick, F. K. 236 Peto, G. 234 Petrii, 0. A. 157 Petr6, J. 108 Petrocco, G. 85 Petrov, E. S. 161 Petrov, Z. E. 238 Petrova, V. 101 Pfeffer, M. 111 Phillips, J. 38 Piacenti, F. 163 Pieters, R. J. 111 Pietropaolo, R. 40, 236 Pietrzak, R. 230 Pinel, C. 111 Pinna, L. 44, 239 Piratinskaya, I. I. 228 Piron, D. L. 106 Pirozhkov, S. D. 42 Pisano, C. 161 Plowman, J. 46 Poddar, R. K. 163 Wtschke. G. 0. 230

Rhu , R. Reddy, N. P. Reed& J.

Reilly, M. Reita, C. Remsen, E. E. Resaseo, D. E. Reut, S. I. Rhodes, S. M. Richardson, J. T. Richardson, T.

Roberts, G. G. Rochester, C. H. Rokwicz, J. Romanello, G. Romero, J. R. Romoda, I. Roobeek, C. F. Ros, M. B. Rosamilia, J. M. Ross, P. N. Roth, S. A. Rotondo, E. Row, J. P. Roy, S. Rozenfeld, B. Riihlicke, D. Ruiz-Montes, J. Russell, C. E.

R q M d t , L.-P.

Ro, J . 4 .

Sabatino, L. Sabo-Etienne, S. Sacchi. M.

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105 162 240

Nassibian, A. G. 165 Okaiaki, H. 110 Ponec, V. 159 Sachtler, W. M. H. 160 Natamian, S. R. 106 Olthuis. W. 137 Powv, S. V. 159 Sainz, D. Nathan B. H. 137 Onggo,’D. 102 Plrta,’F. 34 Saito,.H. Nau, P.-E. 113 Onishi, K. 110 Potemski, R. M. 165 Saito, Y. Navarro, M. I I I Onuki, J. 113 Potgieter, J. H. 163 Saitoh, J. Nazeeruddin, M. K. 37 Orchin, M. 109 Pradier, C.-M. 152. 159 Sakaguchi, H. Nechay, B. 164 Neely, W. C. I55 Neibecker, D. 162 Nekrasova, N. V. 103 Neophytides, S. 108 Neri, G. 40. 236 Nesloney, C. L. 162 Neta, P. I05 Neubauer, H.-D. 107 Nevell, T. G. 160 Newbery, S. M. 164. 228 Nicolet, M.-A. I13 Nicolics, J. 158 Nie, €I.-Y. 240 Nieh, C. W. 32 Nieman, G. W. 154 Nieuwenhuys, B. E. 155 Nifant’ev, E. E. 239 Nihant, N. 23 I

Orij, E. N. Oro, L. A. Ortar, G. Osawa, S. 0 t h J. Ou, E. C. Ouahabi, M. Oudar, J. O’Sullivan, J.

239 41, 162

161 233 44

152 39

152 F. 102

Padella, F. 154, 230 Paganelli, S. 42 Pakkanen, T. A. 110 Palanisamy, P. S. 165 Palenzona, A. 34 Panfilov, P. 23, 196 Paradiso, E. 154, 230 Pareja, P. I95

Pramanik, D. Prasad, J. Prasad, K. Primet, M. Prodi, L. Prokes, J. Prosvirin, I. P. hudenziati, M. Puddephatt, R. J. Puglia, C. Pulgarin, C.

Qi, H- Quinn, J.

Raizman, A. Ramaraj, R.

240 Sakai, K. 155 Sakamoto, Y. 165 Sakata, T. 108 Sakuma, T. 104 Sakurai, Y. 228 Salamin, J.-Y. 237 Sales, J. 240 Santini, C. 152 Sanyal, R. M. 85 saris, F. W.

232 Sarma, U. C. Sasaki, H. Sasaki, T.

40 Sashikata, K. 230 Sato, N.

Satoh, Y. Savel’ev, M. M.

229 Savin, W. 158 Sawai, K. 154 Sawano. K. Ning, Y. 32, 33 Park, J. H. 153 Rambaldi, G.

Nishi, Y. 33 Park, J. W. 158 Ramos Tombo, G. M. 44 Scandole, F. Nishihara. Y. 152 Pasaualetti. N. 237 Randall Lee. T. 236 Schaftler. F.

110 233

40, 156 240 234 43

33, 154 36, 37

112 230 157 110 I12 237 46

163 38

156 228 164 43 42 46 36

229 37

229 Nishimoto; S . 4 36 Pat& M. 208 Rar, L. F. 42 Schierba&, K. D. 158 Nishimoto, T. 233 Patel, V. 208 Rausenberger, B. 188 Schmid, B. 44

Platinum MeraLs Rev., 1991, 35, (4) 253

Page Schmidt, L. D. I08 Schneider, H. A. 106 Schiian, N.-H. 107, 236 Schryer, D. R. I07 Schulz, M. 232 Schwank, J. 107 Schwarz, J. A. 107, 236 Schwarz, K. 32 Scott, W. J. 238 Scrivanti, A. 42 Searles, R. A. I87 Seen, A. J. I06 Sellman, D. 232 Selmeczy, A. D. 156

Sempere, M. E. 159 Sen. A. 110. 126

Semancik, S. 106

sen, B. Senocq, F. Sequeda, F. Serrano, J. L. Serroni, S. Shalimova, L. V. Sharipov, G. L. Sharma, K. Shen, X . J . Sheng, S. Sheu, J.S. Shi, M. Shi, Z. Q. Shibata, M. Shieh, P.-C. Shih, W. C. Shih, Y . 4 . Shimizu, Y. Shindo, Y. Shishido, T. Shteinberg, G. V. Shubin, A. A. Shuh, D. K. Siegel, R. W. Silverman, J. Simkovich, G. Sinclair, R. Singh, B. Sinning, H.-R. Sironi, A. Sirotti, F. Skelton, B. W. Skocypec, R. D. Smallridge, A. J. Smetana, W. Smith, A. W. Smith, J. J. Smyth, M. R. Snyder, S. R. Soeda, M. Soga, T. Solomun, T. Solonin, Y. M. Soltyka, A. J. Solymosi, F. Somasundaran, P. Somekh, R. E. Sominskii, S. D. Sridharan, V.

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Page Srinivasan, S. 240 Stamps, R. L. 101 Starosel’skaya, L. F. 238 Stashonok, B. D. 36 Steger, J. J. 40 Steinmetz, P. 82, 105 Stencel, J. M. 39 Stepanov, A. G. 43 Stevenson, S. A. 109 Stoeckli-Evans, H. 163 Stonehart, P. 45 Storey, J. W. V.164, 228 Straschil, H. K. 208 Stuart, J. W. I34

Subramanian, S. 107, 236 Siissfink, G. I63 Sugimoto, T. I52

Suk, M. Y. 158 Sukirthalingam, S. 161

Sudrez, M. P. 160

Sugimura, K. I02

SumiyamaK. Sun, Y.-H. U i k , M. V. Susini, P. Suwa, M. Suzuki, M. Suzuki, T. Suzuki, Y. Szab6, S. Szatanik, R. Szpak, S. Szymanski, K.

Tabun-Ek, T. Tagliatesta, P. Taha, F. 1. Takahara, H. Takao, K. Takasu, Y. Takaya, H. Takehayashi, S. Takehara, Z. Takehara, Z.4 . Takenaka, H. Takenoshita, H. Talzi, E. P. Tamura, R.

33 39

154 154 1 I3 157 93

152 I08 230 233 229

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I l l 43 I10

Tanaka, M. 229, 238

Tanaka, Y. 230, 240 Tang, S. L. 228 Tanigaki, Y. 1 I3 Tanke, R. S. 44 Tao, T. 112 Taqui Khan, M. M.

70. 104, 237 Tata, A. Y. 160 Tateishi, N. 157 Taube, H. 23 1 Tauster, S. J. 40 Tejedor, P. 106 Tejero, T. 237 Teleshev, A. T. 239

Tanaka, S. 93

Tenaglia, A. 45

Page Teplitskaya, G. L. 103 Teranishi, T. 40 Terekhova, M. 1.161, 238 Terranova, E. 45 Theden, U. 164, 228 Thomas, G. 102 Thompson, D. T. 195 Thorimbert, S. 161 Tian, D. 230 Ticianelli, E. A. 240 Timofeev, N. 196 Tischler, M. A. 165 Tolstikov, G. A. 233 Tombesi, A. 240 Tommasini, S. 23 1

Tong, X. Q. 138. 153 Tornell, B. Torres, W.

Tonegawa, T. 101

Torvela, H. Tosbima, N. T6th, I. Tower, J. R. Toyota, N. Tran, V. H. Trasatti, S. Treger, Yu. A. Tremont, S. J. TroC, R. Tronconi, E. Trost, B. M. Trovarelli, A. Triibenbach, T. Trzeciak, A. M. Tsaur, B.-Y. Tsiovkin, Yu. N. Tsong, T. T. Tsubomura, H. Tsuji, J. Tsukahara, K. Tsuru, S. Tu, K. N. Turney, T. W. Turro, N. J.

Uchida, S. Uehara, I. ~~

Uemiya, S. 38, 154, 164 Ukei, K. 156 Umemura, S. I65 Uneyama, K. 161 Upchurch, B. T. 107 Urabe, K. 43 Uriarte, R. J. 110, 238 Uriel, S. 237 Urisson, N. A. 232 Uziel, J. 161

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Vaganov, A. G. 35 Valero, C. 162 Vallet, C. E. 36 Van, Y. 23 1 Van Asselt, R. 161 Van Den Aardweg, F.239

Page Van Der Donk, W. A.238 Van Der Kraan, A. M.

229 Van Der Linden, W. E.

137 Van Der Weg, W. F. 101 Van Diemen, J. H. 105 Van Kerkhof, J. C. 137 Van Kesteren, H. W. 112 Van Leeuwen, P. W. N. M. 43, 239

Van Rooy, A. 239 Van Staden, M. J. 34 Vanloon, K. R. 101 Vannice, M. A. 109 Vargaftik, M. N. 230 Vassilakis, D. 152 Vayenas, C. G. 108 VBzquez, J. L. 34 Velichko, S. M. 43 Venalinen, T. 110 Venanzi, L. M. 44 Veracini, C. A. 237 Vercesi, G. P.

95, 105, 157 Vest, R. W. 235 Vickers, V. E. 45 Vijh, A. K. 35 Viswanathan, B. 237 Vitin’sh, A. 157 Vlachopoulos, N. 36, 37 Voloshin, A. I. 233 Von Gruenewaldt, G. 96 Vos, J. G. 105 Vu, Q. T. 1 I3

Wachter, P. 153 Wada, 0. 112, 240 Wada, Y. 233 Wadsworth, J. 153 Waegell, B. 45 Wagner, F. E. 36 Wahren, R. 1 I3 Wakabayashi, N. 35 Wall, R. N. 230 Wang, G. 44 Wang, H. 37, 104

Wang, R. 21 Wang, W. 102 Wang, X. Z. 165 Wang, Y. 32 Wang, Z.-M. 21 Ward, T. R. 44 Wasserman, E. F. 101 Watanabe, H. 161 Watanabe, K. 33, 152 Watanabe, M. 157 Watanabe, T. 163 Watanabe, Y. I 1 1, 230 Watkins, L. M. 1 1 1 Weber, W. H. 101 Webster, D. E. 94 Weertman, J. R. 154 Weir, B. E. 46

Wang, J. 106


Page Werner, H. 232 Wertz, D. W. 233 Wessel, T. J. 235

Whang, C. N. 153

White, C. W. 36 White, H. S. 234 White, J. M. 235 White, P. 140, 200 Whitesides, G. M. 236 Wiemhofer, H. D. 158 Wilczok, U. 229 Wilde, M. 107 Wilkinson, G. 34 Williams, D. J. 45 Williams, R. S. 38 Winterbottom, J. M. 160 Wittmer, M. 164 Wokaun, A. 107

Wey, J. P. 155

White, A. H. 102

Puge Wolf, R. M. 155 Wolfson, S. K. 35 Woodhouse, J. 8. 101 Woollam, J. A. 152 Worley, S. D.

40, 108, 155 Wu, J. C. S. 42 w u , s. c. 230 wu, w. 156

Xiao, Q. F. 32 Xing, X. 232 xu, c.-L. 42 Xu, D. 38 xu, Y. 102 Xue, Z. 38, 112

Yahikozawa, K. 157 Yakimenko, L. M. 35 Yamada, M. I l l

Yamaguchi, H. Yamaka, E. Yamamichi, S. Yamauchi, S. Yamazoe, N. Yang, S.-Z. Yao, S. J. Yaoita, M. Yasuda, K.4 . Yates, J. T. Ye, S. Yeager, E. Yeo, J. K. Yermakov, A. Yoshida, Y. Young, P. A. Yum, E. K.

Zaki, M. I. Zaks, I. A.

Puge I12 240 112 I65 38

234 35

I65 165

109. 140 102 232 238

23, 196 165 152 43

I40 102

Puge Zamashchikov, V. V. 161 Zanicchi, G. I54 Zassinovich, G. 44 Zeijlemaker, H. 46 Zeltser, A. M. I55 Zeper, W. B. 31. 112 Zhang, L. I53 Zhang, S. L. 33 Zhang, S.-W. I63 Zhang, W.-R. 234 Zhang, Z. 160 Zhorov, E. Yu. 44. 239 Zhou, X. C. 152 Zhou, Y.4. 42 Zhu, J. G. I12 Zhukova, T. B. 103 Zhvanetsky, 1. M. 40 Zimmerman, T. 42 Zink, J. I. 38 Zubkowski, J. D. 37

SUBJECT INDEX TO VOLUME 35 a =abstract Page Absorption, H, by Pd, a 154, 157 Acetalisation, by Rh(II1)triphos complexes, a 44 Acetals, activation, a 111 Acetone Oxime, carbonylation, a 163 Acetonine, synthesis, a 163 Acetophenone, a 44, 239 Acetylene, reactions, a 40, 159, 163, 236 Adsorption, by IrOJTi electrodes, a 157

CO, on I r / A l z 0 3 , a 42 on Pt electrode, effects, a 102 on Pt-Rh/A120,, a 159 on Pt( 100},reaction monitoring 188 on Rh catalysts, a 41

157 AIROF, a 113

111 cinnamyl, hydrogenation, a 40 C, , from syngas reaction, a 159 ethyl, chemisorption on Pt, Pd, Rh, Ru,

bonding study, a 38 flow rate sensor, a 106 from or-alkene hydroformylation, a 43

bonding study, a 38 electrwxidation, on Pt, a 35, 108, 157, 232

on RuO/C, a 36 extensive use in fuel cells, Grove Symp. 209 formation, from CO hydrogenation, a 237 synthesis from syngas, a 41

primary, aerobic oxidation, a 163

synthesis from CO+H,, a 42, 109

formation by hydroformylation, a 43, 239 45

dehydrogenation, a 159, 239 production 152, 161, 195

Alkenes, hydrogenation, homogeneous, a 161, 162 reactions, a 161, 163, 238, 239 hydroformylation, a 43, 239

Alkenyl Iodonium Salt, coupling with olefins, a 238 Alkylation, asymmetric Pd allylic, a 161

Alkylthiols, formation, a 152

H, by Pd/glassy C electrodes, a

Alcohols, allyl, cyclopentannulation, a 110 allylic, for enol production, a

methyl, chemisorption on Pt, Pd, Rh, Ru,

phthalic, electrooxidation, a 111

allylation, a 111

Aldehydes, activation, a 111

Alkanes, bridged.polycyclic, by RuO,, a

Alkylation-Alder Ene, cyclisation, a 110

Page

44, 111, 161, 162 Alkyl-Boron Compounds, polymerisation, a 43

Allenes, carbopalladation, a 44 Ally1 Benzene, hydroformylation, a 110 Allylation, primary alcohols, a I l l

Alkynes, 1-Alkynes, reactions, a

Allylic Acetates, for or,P-unsaturated ketones, a 1 1 I Allylsilanes, synthesis, a 162 Aluminium, grain boundary reaction with

Pd-Ag-Cu, a 153 Amines, carbonylation 70 Ammonia, carbonylation 70

in nitric acid production, a 236 oxidation, on knined gauze 58 photoproduction, from N2, by Pt/CdS system, a 104 reaction with CO, a 108 sensor 200

Amorphisation, on milling Pd-Si, a 154 platinum metals, solid state 83

Aniline, for diphenylurea, a 238 Anion, tandem capture-cyclisation, by Pd(O), a 161

110 Aromatisation, n-heptane, n-hexane, a 39, 40, 107 Aryl Halides, carbonylation 70 Aryl Iodides, coupling, a 237

43 Aryldithiocarbamats, a 237 Aryl-Aryl, exchange, a 238 Ascorbic Acid, oxidation, by Ru complexes, a 233

Barrier Layers, a 45, 46, 112, 113, 164, 240 Benzene, formation, a 160, 236 Benzonitrile, electrocatalytic hydrogenation, a 103 Bismuth, effect on lactose oxidation, a 40 Bonding, fusion, a 235 Book Reviews, Precious Metals Science

for HCN synthesis, a 160

Annulation, by Pd catalyst, a

reaction with vinyl-, cyclopropane/butane, a

and Technology 93 The Platinum Yearbook 1991 137 “Platinum 1991” 132

Bushveld Igneous Complex 132 Butane, n-, hydrogenolysis, isomerisation, on Pt, a 235 Butanediols, electrwxidation, a I l l

Cameras, IR 45, 64 Cancer, anti-tumour Pt complex, a 46

46 metal complex anti-cancer drugs, review, a


Page I I ? Capacitors, with Pt/Ta barrier layers. a

Carboannulation, vinylic cyclopropanes.

Carbon Oxides, CO, adsorption. on Ir/Al:O,. a 42 on Pi, Rh, Pi-Rh catalysts. a I59 on Rh(1). Rh(I)/TiO,, a 41

chemisorption. on Pt-Sn/Al,O *. a 107 on Pt/AI,O,. TiO,. a 235

CO-NO, Ce. K effects on Rh/AI,O,. a 41 cycling, for Pd/AI,O, restructuring. a 40 detection in presence of NO. SO:. a 235 effect on ethene hydrogenation. a I07

32 electrooxidation, see Electrodes for aromatic nitro compound reduction. a 162 for diphenylurea. a 238 hydrogenation, on Rh catalysts. a 109, 160. 237

on Ru clusterslinorganic oxides. (1 42 interaction with 0, on Ir/Al,O,. a 42 on,Rh!Al,O,, displacement by PHI. a 109 oxidation, on Pt/SnO, , a I07

on PdCI,-CuCI,/AI,O,,C. a 109 poisoning on Pd/SiO,. characterisation. a 41 reaction with NH , a I08 see also Synthesis Gas self poisoning on Pt{100) surfaces I88 sensors, a 38. 106. IS8

CO, CO,, hydrogenation. high pressure. n 40 low fuel cell emissions, Grove Symp. 209

C O , , effects on H permeation through Pd. a 32 hydrogenation. on RhiTiO, .RhlNb,O,, a 41

cyclobutanes, a 43

on H permeation through Pd. a

Carbon Tetrachloride, hydrodechlorination. a 43 Carbonitriles, a-methoxy. formation. a I l l

Carbopalladation, allenes. a 44 Carboxylic Acids, reactions, a

Carbonylation, reactions. a 43. 161. 163 by Ru carbonyl complexes 70

43. I l l Carboxylic a-Amino Acids, synthesis. a 161 Catalysis, biphasic, a I62

by Ru carbonyls 70 heterogeneous, a 39-42, 106-1 10. 159-160, 235-237 homogeneous, a 42-45, 1 1 0 - 1 12. 161-163, 237-239

Catalysts, EUROPT-I, for CH, conversion I95 for diesel engines 178. 187 Iridium, wire, for HCN synthesis, a I60 Iridium Complex, stabilised by 0 donor

I r /AllO, , CO+O, adsorption, interactions. a 42 Irlsupport, precursor stoichiometry. a I07 Osmium Complex, OsHCI(CO)(PIPr, 1 , .

hydrosilylations, a I62 IH, 0 s , (CO),l/poly-naphthalene, olefin

isomerisation, a I l l Palladium Complexes, Pd acetate + di-imine

ligands, vinylations, a 43 PdCl l(dppf). polymerisations, a 43

by cluster compounds 10

three-way. SAE conference 94

ligand, hydrosilylation, a 44

PdCl 2(PhCN),. aryldithiocarbonimidate

PdCl ,(Ph, P), styrene

PdCl,/Ph, PC,H,SO ,Na, heptene

Pd(0). tandem cyclisation-anion capture, a

Pd(O)L,+vinylic/arylic halides, carbopalladations, a 44

Pd(I1). Alder ene reaction, a Pd(1I) acetate, carbo-, heteroannulation, a Pd(II), alkyne-cyclopalladations, a I l l Pd(l1) +onium salts + triphenylphosphine,

for diphenylurea, a 238 Pd(OAc), , @-vinylation, a 161

C-C coupling. a 238

rearrangement, a 237

hydrocarboxylation, a 161

hydrocarboxylation. a 238 161 I10 alkylation of ally1 substrate, a

110 43

Catalysts fcontcl.) Puge Pd(OAc),. H? +CCI, reaction. (1 43

reactions, a 237

triflate reactions. ( I 238

Pd(OAc),. Pd(PPh,), . PdCI,. coupling

Pd(OAc),(PPh,), +Cu iodide. vinyl

Pd(OAc), +( +)DIOP. asymmetric alkylati

Pd(0:CC PI

ons. (I 161 I26 ' . H . ) ? . mild CH, oxidation

i(PFu ,)[CI, . cyclohexenone annulation. a 238 ,-p-CH < ) I , aryl-aryl Pd(PPh ) : (C H.

exchange. (I 238 Pd,(dba),.CHCI * . coupling reactions. ti 161 (DIAN)Pd(olefin). hydrogenations. a 161 IPd(pyridine. phosphine)l(BF, ),.

dimerisations, a I10 I(dppp)Pd(solvent),I[Xl ,. carbonylations. LI 161

Palladium, industrial uses. review. ( I 44 poisoning by metal ions, a I08

Pd, Pd-Pt, Pd-RhlC, SiO,, TiO,, propylcne oxidation. a I60

109 PdCI?, PdCI,-CuCI,/AI,O,, CO oxidation. ( I

PdCll +Keggin-type heteropoly anions, reductive

PdCl, /CuCI? IHOAc, propylene oxidation. LI 43

Pd( l l l ) , sulphided. C ? H , cyclisation. (1 236 I ox

Pd-BilC, lactose oxidation. ( I 40 PdlAIPO,, styrene hydrogenation. ( I I 59

I ox CO-NH, reaction. u I08 surface restructuring o n CO cycling. ti 40

Pd/Al,O,:SiO, +Na. Fe, Mn oxides, preparation. structure. properties. u I08

Pdla-Al ,O, , C ,H , hydrogenation. ( I 236 PdlC, reaction of pyrimidine nucleosides +

vinyl/allylic triflates. ( I I60 PdlF-polymer Nation, olefin conversion. u 106 PdlHY, pretreatment. Cr promoter effects. LI 109 PdlHY, /NaHY, /Nay. methylcyclopentane

conversions. n I60 PdlLa,O, , in high pressure IR cell.

hydrogenation. ( I 40 PdlMgO. phenol hydrogenation. LI 236 PdlNaY, lCaY zeolites, HC conversions. LI 160 PdlPTFEINafion, cyclohexene hydrogenation. ( I 106 Pd/rare earth oxide, support effects. ( I I09 PdlSAPO-I I , I -hexene conversion. I I 40 PdlSiO,, characterisation. MCP

hydrogenolysis. a 41

carbonylation. a 43

PdS/AI:O,, hexene-l hydrogenation. a I59

Pd(Pt)/AI:O,, S poisoning. ( I

PdlA1,O $, CH, oxidationiconibustion. ( I

promoted, MeOH synthesis. ( I 41 Pdlsupport, H combustion. ( I I60 Pdly-Al,O,, C ,Hl -C ,H, hydrogenation. ( I 40 Platinum Complexes, bis(divinyltetraiiicthyl-

disi1oxane)Pt. colloid formation. ( I I10 Pt blues. H: evolution. ( I 43 PtX,(CO)(C,H, "). synthesis. t i 237 IPt(C ,H4) ( ( +)-DIOP)+PtCl ,((+ I-DIOP)I.

hydrciformy lat ion. ( I 41 Pt(ll)-NaI-HCIO,-HIO. vinyl halogenidc

reduction. ( I 161 PI-H. +Ph ,Si(C =CCMc ): . ring .rysteiiis.

with phosphinito ligandb. hydrofmnylation. (143 cis-IPtC12(PPh ,O,I/SnCI,. oletin

Platinum, diolefin(dialkyl)Pt(lI) hydrogenation. ~1236 236

Pt, Pd, Rh, Ir , acetylene hydrogenation. C effects. ( I IS9

Pt black, for Pt complex hydrogenation 236 Pt clusterslchelate resin-Na, Mg, Al

complexes, preparation. ( I 40 Pt oxideslTiO,, CdS, aqueous phntncatalytic

alkenyl silanes. LI 42

hydroformylation. ( I I10

in nitric acid production. t i

cyclisation. ( I 36


Catalysts (conrd.) Page Pt planes, olefin hydrogenation, a 159 Pt(lll), CH,I, CO coadsorption, a 235

Pt-Ce/SiO,, microstructure, reactivity, a I08 Pt-COX, 0 electroreduction, a 103

Pt-IrlAl,O ,, n-heptane aromatisation, a 107 Pt-IrlAl,O,, -no,, /TiO,, support effects, a 236 Pt-Ir/support, precursor stoichiometry, a 107 Pt-Ni-Nb-Sn-Pt, HCHO electrooxidation, a 157

Pt-Re/Al,O1, &hydrogenation, preparation, a 107 Pt-SnlAl, 0 ,, chemisorption, XPS, a 107

n-heptane aromatisation, a 107 IPtCI,(SnCI,),lz -/y-Al,O,, alkane

dehydrogenation, a 159 Pt/, Pt-Rh/Al,O,, CO adsorption, a 159 Pt/AI,O ,, cinchona-modified, ligand-

Pt-Au colloids, H, photoevolution 22

Pt-GalAl,O,, n-hexane conversion, a 39

Pt-Re-S/AI,O,CI, reforming reactions, a 39

accelerated catalysis, a 39 ethene hydrogenation, CO effects, a I07 S poisoning, SMSI, a 235

Pt/AI,O, pillared clay, hydrocracking, isomerisations, a 159

R/AI,O,-CI, deactivation on coking, a 235 R/C, H oxidation, a 232 Pt/F-polymer Nation, olefin conversion, a 106 Pt/H-mordenite, n-heptane hydroconversion, a 107 PtlKL, n-hexane aromatisation, a 40 Pthylon, Sn-Ptlnylon, liquid-phase

hydrogenation, a 40 Pt/Pr,O, ,, alcohol production, from syngas, a 159 PtlPTFEINafion, cyclohexene hydrogenation, a 106

106 Pt/SnO,/SiO,, CO low temperature oxidation, a107 Ptlsupport, precursor stoichiometry. a 107 Pt/TiO,, H photoevolution from H,O-MeOH. a233

S isoning, SMSI, a 235 PtlTiK-ZrO,, n-hexane reforming, a 236 PtlZrO,, polycrystalline, MeOH oxidation, a 108 Rhodium, chiral cationic water soluble

Pt/Rh, low-level moisture generation, a

resistance to HIS, a 39

complexes/cation exchange resins, a Rh colloids, hydrosilylation, a

hydrogenation, a wire, HCN synthesis, a

BINAP-Rh(I), photocatalytic asymmetric

CP*(P(OMe) j)Rh(C I H,)(H)+*

Rh chiral phosphine ligands, asymmetric

Rh chiraU3-al kyl phenanthrol ine ,

Rh phosphine chelate complexes,

Rh/RC@-C,H,SO,Na),, alkene

Rhodium Complexes, asymmetric hydrosilylation, a

reduction, a

dimerisations, a

hydrogenolysis, a

hydrogenation, a

42 238

239 160

239

37

162

162

44

reductions, a I62 RhCI(CO)(PR ,),, pentane

dehydrogenation. a 158 RhPh, PPy, styrene hydroformylation, a 239 Rh(I1) carboxamides, preparation,

cyclopropanation, a 111 Rh(I1)perfluorobutyrate. hydrosilylation, a 162 Rh(PMe,),CI(CO). alkane

dehydrogenation, a 239 238 Rh( +)/DIOP, alkene hydroboration, a

Rh-phosphine, hydroformylation, a 44 Rh-tris(o-rert-butyl-pmethylpheny1)phosphite.

Rh,(CO),, +amine. nitroanisole,

tricyclohexylphosphine Rh(H)CI , ,

hydroformylation, a 239

nitrotoluene reduction, a 239

chloroarene h drogenolysis, a 162 [RhCI ,(triphos){ acetalisations, a 44

Catalysts (contd.) Page [Rh(COD)Cll (S)-phephos, asymmetric

IRh(C0D)Cll , +TMS-CN, acetyl reaction, al I 1 IRh(CO),CIl , +phosphanorbornadiene,

hydroformylations, a 162 IRh(diphosphine)(solvent), 1 +, enol

Rh(0) colloidal particles, hydrogenation, a 162 Rho), Rh(I)/TiO,, CO adsorption, I-hexene

hydrogenation, a 41 Rh-Ag/TiO,, MCP hydrogenolysis, a 41 Rh-Ce/SiO,, microstructure, reactivity, a 108 Rh-Co-CulTiO,, HI +CO reaction, a 42 Rh-Co/Al , 0, , MgO, SO,, propylene

hydroformylation, a 237 Rh-MnlSiO , , CO hydrogenation, a I09 Rh/AI,O,, CO adsorption, a 159

109 ethene hydrogenation, CO effects, a 107 in solar reactor, a 31 interaction with N,, a 155 protection from oxidative degradation, a 109

RhlAI,O, +Ce, K, NO-CO reaction, a 41 Rh/AI,O,-K,CO,, exchange functionalisation 140 Rhly-Al,O,, ZrO,, ZnO, MgO,

c haracterisation , a 237 Rh/MgO, for H/CO reaction, a 231 Rh/Nb,O,, CO, hydrogenation, a 41 Rh/SiO,, NCO formation, a 41 Rh/TiO,, CO, hydrogenation, a 41 IHRh(CO)(PPh ,)I /membrane,

hydrosilylation, a 44

production, a 1 1 1

CO displacement by PH , , a

hydroformylations, a 109 Rh, (CO) /TiO, , CO hydrogenation, a 160 Ruthenium, chiral, synthesis, a 111

RuO,, C-H bond activation in alkanes, a

Ru clusterslinorganic oxides, preparation

Ruthenium Complexes, K[Ru(EDTA-H)C112H,O,

from Ru ,(CO),, , a 42 45

NH , photoproduction, a 104 RuCl(OAc)(PPh ,) , triple system,

RuCI,(PPh,), +NaOH, ketone

RuClJ.3H,0, naphthalene

RuHI(tppts) , , propionaldehyde

Ru(acac) ,, for naphthalene electrooxidation, a 233

Ru(cod)(cot), codimerisation, a 163 Ru(NH,),CI,, for naphthalene

electrooxidation, a 233 Ru,(CO), carboxylates, hydrogenation, a 163 Ru ,(CO) I , +tricyclohexylphosphine,

alkene hydroformylation, a 239 decarbonylation, a 163

IRuBr,(Me,SO),l, PPh, oxidation, a 163 [Ru,(CO),(Me,CNO) ,(Me,CNOH),l,

aerobic oxidation, a 163

hydrogenation, a 239

electrooxidation, a 233

hydrogenation, a 112 RuX,L,, ether oxygenation, a 45

carbonylation, a [(bpy)(trpy)RuOl +, diol oxidations, a [(Ph. PI .NlIH, Ru, 020) I ,1. for .~ ,. . . ~ ~ - _.

cvclohex-Zen- 1 -one. ‘u Ru-CoiCeO,, H-CO reaction, a Ru-Ge, Pb, Sb, Si, Sn/AI,O,, dispersed,

Ru/C, quinoline hydrogenation, a Ru/SiO,, C,H, hydroformylation, a Ru/zeolite-A, preparation, size effect, a Ru , (CO) I , + bpy/Mg silicate, water gas

x-Allylruthenium, for ketone synthesis, a Catecholborane, for alkene hydroboration, a Ceramics, support for Pd-Ag membrane, for

properties, a

shift reaction, a

H permeation, a

163 1 1 1

45 160

110 110 237 42

110 111 238

154


Chloroarenes, hydrogenolysis, a Chloroform, formation, a Chloronitrobenzenes, reduction, a Chloroperbenzoic Acid, reaction with

[Ru(PPh, ),CI , I r a Cholesterol, sensor, a CHP Systems, Grove Symp. Chromium, catalyst promoter, a

for corrosion protection, a grain boundary reaction with Pd-Ag-Cu, a

Cinnamaldehyde, hydrogenation, a Cisplatin, a Clusters, complexes, a

Coal, conversion, a Coatings, 110,-Ta,O,ibase metal electrodes, a

polymetallic activation

Pd, by electroless deposition, a

Pd modified aluminide Pt, by electroless deposition, a Pt thin films, ion beam deposited, a Rh, in reed switches, a

Cobalt, a Codimerisation. acetvlenes +alkenes. a

on Mo-W-Cr alloys

Page Cerium, additions to Rh/A1201, NO-CO reaction. a 41 Chemical Reaction Fronts on Pt{ 100) I88 Chemical Vapour Deposition, a 38. 152 Chemisorption, CO, H, 0 107. 235

38 Chenevix, Richard, palladium discovery 141

I62 43

CO, MeOH, EtOH, on electrodes, a

162

45 I65 209 109 I63 153 40 46

156 10

I12 157 105 133 82

105 112 165 153 163

Cokine. in cataivsts. 'a 235 22, 34, 36,

110, 238, 239 Colloi&, Pt, Pt-hu,'Rh, Ru, Ag, a

Composites, superconducting 2 Conductors, molecular, IPd(tmp)l I IReO,], a Conferences, 12th Natl. Fuel Cell Seminar, 1990

2nd Grove Fuel Cell Symp., London, 1991 2nd Intl. Symp. Metal-H Systems, Banff,

Intl. Symp. Polymetallic Activation, Palma,

Magneto-Optic Recording International

SAE Intl. Congress and Exposition, Detroit,

156 17

209

Sept. 1990 24, 195

Sept. 1990 10

Symposium, Tokyo, 1991 I34

Feb.-Mar. 1991 94 Corrosion, in contracts, a 165

104 protection, in Mo-W-Cr-Pd alloys 133 resistance, Cr+PGM additives in acids, a 163

F ion on IrOlTiO ceramic electrode, a 35 Fe40Cr3Ru steel, a 34 of Ir-Ni electrodes, for OER, a I06 platinised porous Ti electrodes, a 35

2, 23, 156 164

34 Pt complex oxides, formed in crucibles, a 156 Rh-Cu single, solidification, a 155 Ruse,, a 155 single, Ir, plastic deformation 196 single, Pt, Rh, Pd, surfaces, in HISO,, a 228 Y,,Ru,,, Er,Ru,, a 34 n-Si, Pt doped, a 228

Cyclic Voltammetry, for Ru-Ti alloys, a 103 Cyclisation, reactions, a 36, 161, 238 Cyclohexane, reactions 27, 39, 160 Cyclohexanone, a 36, 236

Cyclohexenone, annulation, a 238 Cyclohexylamine, carbonylation 70

1 1 1 42

photo-, CdS in PtlCdS dispersions, a

Crucibles, Ir, Pt Crystallisation, heavy metal fluoride glass, a Crystals, Pd-Ni-P, a I 02

Pt basal single electrodes, a

Cyclohexene, reactions 74, 106, 110

Cyclopentene, hydroformylation, a 110 Cyclopropanation, catalysts for , a

Cyclo-Z-en-l-one, reactions, a 45 Cyclopropane, reaction, on RuNaAESI, a

Page Decarbonylation, [Ir,(CO) , , I isomcrs. a 237 Decomposition, formamide. a 108

hydrazine. a 155 NO, on Pt{ 100) I88

Dehydroaminoacid, derivatives. hydrogenation, asymmetric, a 42

Dehydrogenation, alkanes, a 159. 239 cyclic C, , C, hydrocarbons, a 107 pentane, a 158

46 I06

ammonia 200 cholesterol, a I65 CO, in presence of NO, SO,, a 235 CO, a 38, 106 H 85, 106, 234, 235, 240 H, 0, PdlSnO, model sensor, a 106

164 IR, a 45. 64. 208 laser power, a 158 luminescent, using Ru complexes, a 105 0, CH,, H , , 0,. by PdlSnO,, PtlTiO,, a 158 0,. a 38, 106, 158 strain gauges 65 titration monitor, by Ir oxide device I37

Deuterium, enriched by T in giant Pd cluster, a 230 in self assembly of catalysts, a 236

Deuterium Exchange, in styrene, a 161 Dienes, reactions, a 40, 44, 107, 159, 237

synthesis, a 161, 163 Diesel Engines, emission control 94, 178, 187

Royal Commission on exhaust control I87 Diffusion, H, in Pd-Ag, a-Pd, PdSiH alloys, a

103, 153, 230 Ir dimers, Ir adatoms, on Ir(l lo), a 155 membranes 33. 138 see also Permeability

Diffusion Couples, Pd-AI, kinetics, a 32

Dimerisation. reactions. a 110. 162

Dental, alloys. tarnishing tests, a Detectors, alcohol, with RuO,/C electrode, a

IR, visible, UV, by Schottky diodes, a

Dihydrobenzofurans, production, a 43

Dimethyl Oxalate, selective reduction, a Diodes, Pt-Tilp-InGaAsln-InP, hole trap levels, a Diols, electrooxidation, a Dioxetane, 1,2-, decomposition,

chemiluminescence, a Diphenylsilane, for hydrosilylations, a Diphenylurea, N,N'-, synthesis, a Disproportionation, cyclohex-2-en- I -one, a Dissociation, NO, a DNA, photo chemical cleavage, a

Electrical Contacts, Al-Pd-Si interconnects, a Au flashed Pd, a corrosion, resistance characteristics, a electroplated NilPdNilAu, a in reed switches, a in ULSI, a ohmic, Pd-Inln-GaAs, PdlSb(Mn)pGaAs, a

PtSilGe-SilSi, a Pt-Tilo-InGaAsln-InP, diodes, a

PtlTilp-InAs, a

Schotiky, a

Pd solid solution alloys, +H, a U-PtlPdlRh-In alloys, a

Electrical Resistivity, in Fe-CIAI, O,/Fe-Ru, a

Electricity, efficient generation by fuel cells photoproduction from light, a

Electrochemical Cells. PtlCaF , I P t . in 0,. a

163 46

I l l

233 239 238 45

155 105

I I3 I65 I65 234 165 240 165 46

I12 46

234 23 1

33 32

209 37

I02 Electrochemistry, a 34-36, IOj-lOk, I5%158, 232-233 Electrochrornism, AIROFs, a 1 I3 Electrodeposition, Pd-Ni films 208 Electrodeposition, a 38, 105, 106, 234 Electrodes, anodes, DSA, a 95, 105

Pt, urea oxidation, a 35 112 Wporous SiC+H,PO,, coal conversion, a


Electrodes (contd.) Page

+ (Bi 0 1) u . I (Er,O , h . ,, a 233 Pd thin film disc, H insertion, a 157 Pt, PtlNafionlPE, in 0 sensor, a 38, 158

F ion-IrO/TiO ceramic, effluent treatment, a 35 for OER, preparation, a 106 gas diffusion, Pt, uranous nitrate production, a 164 Ir oxide, in titration monitor 137 IrO,-Ta,O,lTa, /Ti, a 157 IrOJTi, adsorption properties, a 157 Ir-PtlNafion, 117/Pt-Ir, in HCI electrolysis, a 35 Ir,Ti I -xOz/Ti, preparation, activity, stability, a 36 Pd, implantated by K, Li, a 103 Pd, Pt-Pd, for ethylene glycol oxidation, a 103

TiO,/SiO,/Pt, response to gases, a 36 ultramicro, TiO,/SiO,/Pt, gas response, a 36

platinised porous Ti, corrosion resistance. a 35 platinised PI, in cholesterol oxidase sensor, a 165 polymer/polymer/Pt, preparation, a 35 Pt, adsorbed CO effect, a 102

basal single crystal, a 34 CO electrooxidation, a 232 for glucose oxidation, a 232 in cell with Ru naphthalene oxidation, a 233 in 0 sensor, a 158 in phenol oxidation, waste water control, a 232

102 Pt, Pd, Rh, Ru, chemisorption of CO,

MeOH, EtOH, bonding study, a 38 Pt, Pt/C+metal oxides, MeOH oxidation, a 35, 232 Pt black, Pt/WO,, for H detection, a 38 Pt disk fabrication, a 234 Pt gauze, rrans-[PtHCl(PEt,),l oxidation, a 35 Pt, Pd, Rh, Ru/poly(pyrrole-viologen)/glassy

103 Pt rotating disc, for 0, reduction, a 232 Pt(bpy)(CN),/Pt, spectrochemical properties, a 233 Pt-SPE membrane, in fuel cell, a 163 PtlC, for H oxidation, support porosity, a 232

in PEM, a 240 PtlSnO,, FWWO,, in CO sensor, a 38 RuOlC, MeOH oxidation, 0 evolution, a 36 RuO, +TiO,, SnO, activated, a 104 RuO,/C, for alcohol detection, a 106 Ru Ti, -xOz/Ti, catalytic activity, a 36 [Rb(L),CI,I+BF,-, hydrogenations, H,

evolution, a 36 105

Electroless Plating, for Pd thin films, a 38 35

Emission Control, 1991 SAE conference reports 94 diesel exhaust 178, 187 fuel cell benefits, Grove Symp. 209

Energy, more efficient sources, Grove Symp. 209

Enones, conjugated, electrocatalytic hydrogenation, a 103 Enthalpy, of formation, RuGe, RhGe, PdGe, a 154 Environment, fuel cell benefits to 17, 209 Enynes, 1,6-, cycloisomerisation, a 110 Esters, a 45, 161 Etching, Pt foils, in 0 plasma, a 38

Pt-InP photoelectrodes, a 104 Ethane, hydrogenolysis, catalyst activity a 236 Ethene, hydrogenation, a 107 Ethers, luminescence, oxygenation, a 45, 104 Ethyl 2-Formylpropanoate, synthesis, a 162 Ethyl Acrylate, hydroformylation, a 162 Ethyl Chloride, formation, a 43 Ethyl Pyruvate, hydrogenation, a 39 Ethylanthraquinone, 2, hydrogenation, for Pd

catalyst studies, a 108 Ethylbenzene, from styrene, a 236 Ethylene, from vinylhalogenides, a 161

40. 109, 162, 236

cathodes, high temperature,

photo, Pt-InP, etched, a 104

porous in Pt/CaF,/Pt cell, a

C felt, for hydrogenations, a

Electroless Deposition, Pt, Pd, Ni, a

Electrolysis, HCI, by SPE electrodes, a

Enols, catalytic production, a I l l

reactions, a

Page 103. 163

107 178. 187

Ethylene Glycol, reactions, a Ethyne, effect on ethene hydrogenation, a E.E.C., diesel exhaust control

research support 10

Faraday, Michael, history 222

Fischer-Tropsch, catalysts, a I 6 0

Films, anodic Ir oxide films, charge storage, a

Fission, PGM waste reprocessing, a Formaldehvde. a

I13 I I2 PI, focused ion beam deposition, a

“ , Formamide, decomposition, a Formic Acid, electrooxidation, a Fuel Cells, a

12th Natl. Fuel Cell Seminar 2nd Grove Fuel Cell Symp., London,

history MeOH, a phosphoric acid, a

Sept. 1991

Fuel Oil, for syngas production, temperature

Functionalisation, of Rh catalysts, by K measurement, a

Gadolinium Oxide, reaction with Pd+H, a Gauzes, knitted, for NH, oxidation Geology, British Columbia

Pt deposits in USSR Glass, formation, Pd-Ni-P, a

Zr-Ba-La-Al-Na fluorides, Pt nucleation, a 1 6 4 33

PdlUNi,,P,,, internal friction, a 229 Pt-AI, thin films 83

232 I88

Glasses, Pdu.835Slo.165, structure changes, a

Glucose, oxidation, on Pt electrode, a Graphite, oxidation, on Pt( 100)

202 157. 163

108 I57

45, 240 17

21. 209 201 I63 45

I I3 140

154 58 16 96

I02

Heptane, n-, reactions, a 39, 107 Heptene, -1, hydrocarboxylation, a 238 Heteroannulation, vinylic cyclopropanes,

cyclobutanes, a 43 Heterocyclisation, C,H,, a 236 Hexane, isomers, a 160 Hexane, n-, reactions, a 39, 40, 41, 236 Hexene, 1-, reactions, a 40.41.42.70, I l l , 159 Hexene, n-, EtlSiH addition, a 110 History, Michael Faraday 222

“Palladium: or, New Silver” 141 Hydrazine, decomposition, a 155 Hydroboration, of alkenes, a 238 Hydrocarbons, adsorption with H2S, H I . on Pt. a 152

conversions, a I60 diesel engine emissions, catalysts for 178. I87

I12 synthesis from CO+H,, a 42

Hydrocarboxylation, reactions, a 161, 238

Hydrochlorination, olefins, a 231 Hydroconversion, n-heptane, n-nonane, a 107. 109 Hydrocracking, a 39. 159 Hydrocyanic Acid, synthesis, a 160

Hydroformylation, alkenes, a 43. 239 ethyl acrylate, a I62 ethylene, C3H6. on Rh catalyst, a I 09 oct-I-ene, u 239 olefins, a 110. 162

propylene, a 237 styrene, I-hexene, a 42. 239

154 34

catalytic recombination with 0, for moisture generator, a I06 chemisorption, a 107, 157, 235 coadsorption with H,S, HC, on Pt, a I52

low MW, production from coal, a

Hydrochloric Acid, electrolysis, a 35

Hydrodechlorination, CCI,. a 43

polybutadiene, a 44

Hydrogen, absorption, by Pd-Al-La-Ni alloy. u adsorption states on Pt electrodes, a


Hydrogen (contd.) Page codeposited with Pd plating, a 106 detection with CO sensor, a 38 diffusion, in Pd, Pd alloys, a 33, 103, 153, 230 electrooxidation, on h / C , a 232 embrittlement of steel, Pt implanted, a 228 evolution, by Rhnr complex polymers, a 36

from H,O-MeOH, a 233 on silicides, a 35

43 in Pd 24. 33 from H,O photoreduction, by Pt blues, a

~~

in uranous nitrate production, a insertion into Pd disc cathodes, a metal svstems

164 157 195

oxidation, on Pd/support, a 160 permeation, through Pd, Pd-Ag membrane

32, 138, 154 photoevolution 22, 104 photospillover, in ZnO/Pd system, a reaction with NO, on Rh, a Schottky device response to, a see also Synthesis Gas sensors use in fuel cells, Grove Symp.

I05 155 240

85, 106, 158, 234, 235 209

Hydrogen Peroxide, photoproduction, a 233 Hydrogen Sulphide, effects with Pt, a 39, 152

acetylene, a 159 alkenes, a 161, 162, 239 asymmetric, dehydroaminoacid

derivatives, a 42

buta-l.3-diene. isoprene, a 159 cinnamyl alcohol, cinnamaldehyde, a 40 CO, in a continuous flow microreactor, a 160

on basic axides, a 237

on Ru clusterslinorganic oxides, a 42 CO, CO,, on Pd/La,O,, a 40 conjugated enones, styrene, benmnitrile, a 103 CO,, on Rh catalysts, a 41 cyclohexanone, a 36

C,H,, C,H,, C,Hb, a 236 C 2 H I - C 2 H I , a 40 diene, olefin, a 40 dimethyl oxalate, a I63 diolefin(dialkyl)Pt(II) complexes, a 236 ethene, a 107

ethylanthraquinone, 2-. for Pd catalyst studies, a 108 hexene- 1, a 41, 159 phenol, a 236

110 styrenes, a 159 transfer, ketones, aliphatic, aromatic, a 239

Hydrogenolysis, asymmetric, Na epoxysuccinate. a 162 biphasic, a I62 chloroarenes, a 162 ethane, for catalyst activity, a 236 methylcyclopentane, on Rh-AglTiO,, a 41 methylcyclopropane, a 41 n-butane. a 235

Hydrolysis, cis-PtCI,(NH,),, a 38 Hydrosilylation, alkynes, a 44, 162

asymmetric, acetophenone, a 44, 239 phenylacetylene, a 162 Pt colloid formation, a 110 Rh colloid catalysis, a 238

Imines, a 111. 161 Imino Acids, photocatalytic cyclisation, a 36 Impedance, Pt/SiO,, ultrathin films, a 32

Hydrogenation, acetophenone, a 44

unsaturated carboxylic acid, a 1 1 1

on Rh-Mn/SiO,, a 109

cyclohexene, a 106

ethyl pyruvate, a 39

propionaldehyde, a 112 quinolines, on Ru/C, Raney Ni, a

of cyclohex-2-en-l-one, a 45

Indans, production, a 43

Page Indium, grain boundary reaction with Pd-Ag-Cu, a 153

Integrated Circuits, a 112, 113 Interconnects, Al-Pd-Si metallisation, a 1 I3

33 Ion Plating, for h-GaAs Schottky contacts, a 234 IR, imaging, sensors, a 45, 164, 208 IR cell, for high pressure spectroscopy, a 155 Iridium, crystal cleavage 23

diffusion on Ir(I 10) surfaces, a 155 plastic deformation 196 radioactive, reprocessing 202 thin films, a 38

Iridium Alloys, Ir-Al quasicrystals 21 Ir-Ni, for OER electrodes, a 106 Ir-Ta, amorphous, diffusion barriers, a 46

Iridium Complexes, polymetallic activation 10 [Ir6(CO),bl, isomer synthesis in NaY zeolite, a 237

1 I3 coatings for DSA electrodes 95, 105 in titration monitor I37 IrO,.nHIO clusters, redox states in H 2 0

photoreactions, a 105 64

Isocyanate, formation, a 41, 108 Isomerisation, direction of 28

39. 110, 111, 159, 235 Isomers, in Pt, Pd complexes 28 Isoprene, hydrogenation, a 159

Johnson, Percival Norton, palladium discovery 14 1 Johnson Matthey, Prince of Wales Award

for Innovation 20 1 “Platinum 1991’’ 132

Joining, PtSi fusion bonding, a 235

Ketones, a 1 1 1 . 161, 239

Lactose, oxidation, a 40 Langmuir-Blodgett Films, a 102, 233, 234 Lasers, a 107, 158 Lead Alloys, Pb-Cu-Sn-Se-Pd, microstructural

Luminescence, in Pt(bpy)(NH,), ’ +-anthraceno-

Indolines, production, a 43

Ion Beam Mixing, Pd-Ni, low temperature, a

Iridium Oxide, AIROFs, a

Iridium Silicide, in IR imagers

reactions, a

stability, a 33

crown ether, a 104 in Ru(I1)polypyridine complexes, a 105 quenching, Ru(bpy) , ’ + , a 37. 158 Ru(bpy),CI,. a 233

Magnetism, Ce-Ru-SiGe. a 102 diamagnetic transition in Pt ID complex, a 153 effect on Ru multilayer films, a 23 1 FeRuGaSi thin films. a 155 Fe(Pd,Pt, --x),l a 101 in Fe-Pd alloys, a 33 in PdlCo multilayers, a 31, 101. 234 in Pt complex oxides formed in crucibles, a 156 in Pt/Co, a 31, 112, 152 in U-Pt/Pd/Rh-In alloys, a 32 in IPd(tmp)I,[ReO,l, a 156 of Pt resistance thermometer, a 113 Pt-Fe-Nb system, a 152 PtlFe multilayers, a 152 Pt,Mn-Pt,Fe, paramagnetic susceptibility, a 228 PtlMn,.,Fe,., , a 229

Magneto-Optics, conference report 134 in Co/Pt, Co/Pd multilayers 31, 112 thin, ultrathin Pt/Co, a 152

Medical, a 46, 165 anti-tumour complexes, a 46 dental alloys, a 46

Membrane Reators 27, 164 33

F-polymer Nafion, PTFE/Nafon, supports, a 106

Manganese, catalyst promoter, a 109

Membranes, for H diffusion, a


Membranes (conrd.) Page Pd, H permeation through, CO, CO, effects, a 32 Pd-Ag, for H permeation 138, 153, 154 Pd/ZnO, H photospillover. a 105 see also Thin Fi lm

Mercaptans, formation, a 152 Merensky Reef I32 Metallisation, systems, a 165, 240 Metallisations, Au-Sn/Pt, Al-Pd-Si, a 112, 113 Methane, formation, a 237

gas detector, a 158 reactions, a 108, 126, 160, 195

Methanol, fuel cells 163, 209 see Alcohols, methyl

Methyl Acrylate, dimerisation, a 162 Methyl Formats, decomposition into syngas, a 163 Methyl Trifluoroacetate, from CH, 126 Methylcyclohexane, selective dehydrogenation, a 107 Methylcyclopentane, reactions, a 41, 107, 160, 235 Methylcyclopropane, hydrogenolysis, a Methylnaphthalene, 2, oxidation, a Methylstyrene, a-, hydrogenation, a Methyl-2-Oxobutanoic Acid, 3-, photocatalytic

asymmetric reduction, a MicroscoDv, scannine electron. with RuO. in _ _ -

imaging, a Mineralogy, in Canada Mirrors, Rh/C multilayer X-ray, a Moisture, generator, a Molybdenum, Pd catalyst promoter, a Morphology, back scattering electron detector, a

Ptlgraphite thin film, a Pt/SiO,, 25A, a

Naphtha, reforming, a Naphthalenes, oxidation, a NEMCA, for MeOH oxidation, a Neohexene, Et ,SiH addition, a Nicholson, William, palladium discovery Nickel, high temperature reactions with Sic, a Nitric Acid! process gas filtration, a

production, on knitted gauze Nitroanilines, reduction, a Nitroanisole, p-, reduction, a Nitroanthraauinone. 1-. reactions. a

41 233 236

37

39 16 39

106 43 39

152 32

39 233 108 110 141 153 236

58 162 239 162

Nitrohemen;, reactions ' 43, 70, 162, 238 Nitrogen, reactions, a 104, 155 Nitrogen Oxides, NO, dissociation, reaction

155 NO-CO, Ce, K effects on Rh/AI,O,, a 41

188 Nitrotoluene, reduction, a 239

Noril'sk-Talnakh, Pt deposits 96

160

with H on Rh, a

self poisoning on Pt{ IOO}

Nonane, n-, hydroconversion, a 109

Nuclear Fuel, FGM reprocessing 202 Nucleosides, C-5 alkyl, production, a

Octane, n-, hydrocracking, isomerisation, a 159 Oct-lene, hydroformylation, a 239 Olefins, couplings, a 161, 238

40, 110, 111, 159, 162, 237 Optical Switch, in Langmuir-Blodgett film, a 234 Organofluorophosphines, complexes, preparation,

properties 86 Osmium, polycrystalline, thermionic emission, a 230

Osmium Complexes, 0 s organofluorophosphines 86

OsH,(PMe,Ph), , concurrent photodissociation, a 37 OsO,, oxidant 31 0s-ammines, a 23 1 Os,h(CO) I i(PPh,)z 9 a 156

Pt ,Os, (CO) ,, (COD), Pt I Os, (CO), ,(COD), , a 156 [OsCI(NO)(PiPr,), 1, synthesis, a 232

reactions, a

Osmium Alloys, Al-0s quasicrystals 21

0 s polyhydrides, paramagnetic, a 37

polymetallic activation 10

Oxidants, (Ph,)IRuO,(OAc)CI,l, a 45

Page Oxidation, 2-methylnaphthalene, naphthalene, a 233

alcohols, primary, aerobic, a I63

ammonia, on knitted gauze 58 CO, on Pt{lOO] crystals, reaction monitoring 188 CO, a 107, 109 electro-, CO, on Pt electrode, a 232

I l l ethylene glycol, a I03 glucose, a 232 H. a 232

alkanes, bridged polycyclic, a 45

diols by Ru complex, a

HCHO, a I57 HCOOH, MeOH, a 157 MeOH, on Pt, a 35, 36, 108, 232 Pd, electrodissolution, a I57 phenol, water pollution control, a 232

Fe,,Cr,Ru steel, corrosion resistance, a 34 graphite, on Pt( 100) 188 H, a 160 internal, in Pd-4OAg-IRE alloys, a 33 lactose, on Bi-PdC, a 40 methane, by Pd 108, 126 photo, H 2 0 , ascorbic acid, a 105, 233

43. 160

resistance, in Pd coated Mo-W-Cr-Pd alloys 133 74

propylene, propylene glycol, a PtlNi crystals, a 101

_ . 163 35

Rh, high temperature, a triphenylphosphine, a urea. a [Ru('PPh,), CI ,I, a trans-[PtHCI(PEt,),l, a

Oxygen, catalytic evolution, from MeOH, a catalytic recombination with H, for

moisture generator, a chemisorption, on Pt-Sn/Al , 0 , , a evolution, by IrO,-Ta,O,lTa electrodes, a

electrodes for, a from HCIO,, a from H,SO,, a

interaction with CO, on Ir/AI,O,, a interaction with Pt/CeO, sensors, a reduction electrocatalysts, a reduction in H,SO, +phenanthroline, on

sensor, a Pt rotating disc, a

Oxygenation, aliphatic ethers, a Oxyhexatriene, cyclisation, a

Palladium, addition, to stainless steel, a to Au-Cu dental alloys, a

or-Pd, H permeation in, a amomhous intemhase with InP. a cluster, Pd,,,Phkn,,(OAc),,,, a clusters, on mica, scanning force microscopy

compounds, cyclopalladated, reaction with study, a 229

~. 45 35 36

I06 107 157 106 104 95 42

158 103

232 38, 158

45 238

I63 46

I03 153 230

. . alkynes, a I l l

Fe(Pd,Pt, -2,. magnetism, a 101 EuPd,Si,, valence change under pressure, a 229

PdGe, enthalpy of formation, a 154 IPd(tmp)l , IReO, I , a 156

electrodes, see Electrodes electrodissolution, a 157 electroless deposition, a 105 glasses, Pd,,Ni,,P,,, internal friction, a 229 history, discovery, a 141 in contacts, a 113, 165 in detectors, sensors, see Detectors in membrane reactor, a 164 in Schottky contacts, a 240 ion beam mixing in Ni, a 33 membrane reactors 27 membranes, a 32, 105 modified aluminide coatings 82 nanocrystalline, mechanical behaviour, a I54

Platinum MetaIs Rev., 1991, 35, (4) 261

Palladium (conrd. ) Page NilPdNiIAu. composite for contacts, a 234

228 Pd(l1l) . sulphided. for C,H, cyclisation. a 236 Pd-AI thin film. phase formatrion. a 153 Pd-H systems, Intl. Symp. 24. 195 Pd/AI diffusion couple, a 32 PdlCo 31. 101. 134, 234 PdlSnO,. for gas sensor. a 106. 158 Pd.C, _”. thin films. electrical orowrties. a 101

Pd( l l I ) . crystal surface in H,SO,. a

p l a h g . k i th H codeposition, a’ radioactive, reprocessing rod, electrochemical charging. a thin films, a 38. ultrafine particles. for H absorption.

‘

adsorption, a

characteristics. a Palladium Alloys, assessed for contact

Pd solid solution. electrical resistivity. a Pd-Ag, H permeation 138. 153. Pd-Ag-Cu. grain boundary reactions. a Pd-40Ag-lRE. internal oxidation. a Pd-Ag-Y(Gd), diffusion characteristics. a Pd-Al-La-Ni, H absorption, a Pd-Au. lattice expansion, a Pd-Au-Cu, dental, tarnishing tests. a Pd-Cr, in strain gauges Pd-C-Mg, a Pd-Er, preparation. metallography. a Pd-Fe, sputter deposited, a Pd-H systems, Intl. Symp. Pd-Ha. preparation. metallography. a Pd-Ma-W-Cr, oxidation resistance Pd-Ni, H insertion into thin films, a

I06 202 233

54. 229

157

165 33

54, 230 153 33 33

154 I54 46 65

229 I54 33 24

I54 I33 I57 . _ I

plating bath 208 Pd-Ni-P, crystal nucleation, glass formation. a 102 Pd-Pb-Cu-Sn-Se. microstructural stability. a 33 Pd-Pt-U, magnetic transport properties, a 32 Pd-rare earth oxides, coupled reduction. a 154 Pd-Si, a 154. 229. 230 Pd-Si-H, H diffusion, electromigration. a 230 Pd-Te, system constitution, a 33 Pd-Zr, amorphisation 83

Palladium Complexes, H , PdCl 6 , effect on Ag imaging colloids, a 36

isomers 28 ortho-palladated imines, mesogens. a 23 I Pd organofluorophosphines 86 PdLCI,, PdC-H),, Pd(L-2H). a 23 1 Pd(I1)-Sn, a 103 polymetallic activation 10 [Pd(3,3’-bipyridazine),llC10, I , . a I02 lPd,X,(PPrn,),l+ 1,4-benzodiazepines. a 231 [Pd, As (PPh,, 1 , [Pd,Sb,(PPh, ) I , a 156

Palladium Silicides, alloy glasses, structure changes, a33 for H evolution, a 35 mechanical alloying, a Pd,Si, in ULSI, a see also Palladium Alloys, Pd-Si

Patents 47-56. 114-124, 166-176, Pentane, dehydrogenation, a Pentene, 1-, hydrofonnylation, a Permeability, see also Diffusion Permeation, H, through Pd 32. Phase Changes, at Pd/InP interface, a

Phase Diagrams, CeRu,(Ge-Si) a

at PtlGaAs, Si/Pt/GaAs interfaces. a in AI-Pd thin films, a

Fe(Pd,Pt , -J , , a Pd-Te, a RuO, -Bi,O ,-CuO, a

Phenol, a Phenylacetylene, hydrosilylation, a Phenylcarbamate, N-, formation, a Phenylpropanal, 2-, from styrene, a Phosphine, displacing Co on Rh catalyst, a


154 240

24 1-249 158 I10

138, 154 153 153 153 I02 101 33

I55 232. 236

I62 43 42

I09

Page Phosphonic a-Amino Acids, synthesis. a 161 Photocatalysis, a 36-37. 43. 104-105. 158. 233-234 Photodissociation, OsH , (PMe ! Ph) , . a 37 Photolysis, Ru(II) diirnine. u I05 Plating, electroless, Pt. Pd. Ni. a I05

Pd. with H codeposition. a I06 Platinum, addition to YBaCuO superconductor. a 229

compounds. Fe(Pd,Pt, magnetism. a 101 228 Pt I Mn-Pt , Fe. oaramaenetic. a

Pt,Mn,. ,Fe,,. ,‘. magnetism in. a 229 CVD. a I52 deposits. in USSR 96 doped heavy metal fluoride glass. a I64

electrodes. see Electrodes n-Si crystals. a 228

electroless deposition. (7 I05 equilibrium shape. surface energy. ( I

hydrous oxide films. u I02

101 etching foils. ( I 38 high temperature reactions with Sic. o 153

implanted in steel. reduced rmhrittlenient. a 228 in electrical contacts. a 46 in high temperature superconductivity 7

ion beam deposition. a I I 2 mullilaycrcd thin films. preparation. structure. ( I 228 Pt( 100). Pt( I I I ) . for adsorption. a 152 P t ( l l l ) . reactions. a 228. 235 Pt-GaAs. in Schottky contacts. ( I 234 Pt-H bond cleavage. a 35 Pt/CdS dispersions. photocorrosion. a I04

in Schottky NH, sensor 200

Pt/CdS.Ag,S/RuO,. for NH production. a 104 PtICo. in magnetooptic

devices 31. 112. 134. 152, 228 PtiFe thin film multilayers. anisotropy. LI I52 PtIGaAs. SiIPtIGaAs. intermixed phase. t i 153 Pt/mica disks. fabrication. II 234 PtINi. oxidation prevention. ( I 101 Ptlpyrolytic graphite. thin film morphology. a 152 PtITa. Pt/Ti. barriers. II I I2 Pt/TiO,. gas sensor. a 158 Pt{ 100). chemical reaction fronts I88 radioactive. reprocessing ’02 thick films. laser power detection. II 158 thin films. a 38. 101 ultrafine particles. for electrooxidations. I I 157 ultrathin films, /S i02 . properties. a 32 underlayers. in YBaCuO superconductors. II ?40

“Platinum 1991” Platinum Alloys, in PAFC fuel cells. ( I

Pt-AI. amorphisation quasicrystals

Pt-ColC, for 0 electroreduction. II PI-Fe-Nb. magnetic. thermal properties. I I

Pt-Pd. solid solution. for ethylene glycol

Pt-Rh. gauze. for NH3 oxidation Pt-Rh. Pt-Rh-Au. volatilisation. (I

Pt-U-In. magnetic, transport properties. ( I

Pt-Y-B. properties. a

CODPI(CD,)~. Pt surface alkyls. a isomers

o-vinyl Pt(IV), a polymetallic activation Pt blues, for H i photoevolution. a Pt organofluorophosphines PtCl ,,[bis(aminomethyl)dimethylsilanel.

Pt(bpy)(CN) , IPt electrodes. spectroscopic

Pt(bpy)(NH,),,,+: luminescence. a Pt(I1)-diaminobioun. synthesis.

oxidation. a

Platinum Complexes, anti-cancer, (I

OS3,Pt(CO), I (PPh ?)!.

anticancer, a

properties. a

characteristisation, u

132 45 83 ? I

I03 1.52

I03 58 32 32 32 46

236 2R

I56 161 10 43 86

46

233 104

23 I

262

Platinum Complexes (conrd.) Page Pt-Sn bimetallic, a 34 Pt,0s6(CO)Iz(COD). Pt50s,(CO),, (COD), , a 156 R,Ba,CuPtO, , R,Ba ,Cu,PtO,, , Ba,CuPt,O,, a I56 IPtI,(L’)IIBF,l. a 23 I

[Pt(en), lIPt(en) I I , I(CI0, ), . magnetism in, a 153 lPt(L’)l[BF,I, a 23 1

IPt(3,3‘-bipyridazin),1~Cl0,1,, a I02

IPt 2 (p-C=CHPh)(C rCPh)(PEt j ) , IBF, , photochemical atom-transfer, a 104

cis-PtCI,(NH3),, hydrolysis products, a 38 cis-[PtCl , (PPh , 1, a 23 1 trans-IPtHCI(PEt I I , electrochemical

oxidation, a 35 trans-lPt(H)X(PPh,),l. a 23 1

35 from SiClPt high temperature reactions, a 153 fusion bonding, a 235 in IR imagers 45, 64, 208 PtSi, columnar grains. u 32

contact to Ge-Si/Si, a 112 in Schottky diodes, a 164, 228 in ULSI, a 240 hSi/Si( IOO), formation, a 240

108 catalysts by S , a 39, 108, 235 CO, on Pd/SiO,, a 41 self, CO, NO on Pt{IOO} 188

94 diesel exhaust 178, 187 electrolyte effluent treatment, a 35 phenol in waste water, a 232 radioactive PGM waste 202

Polyaldehydes, from polybutadiene, a 44 Polymerisation, a 43, 110 Polymers, co-, Ru complex+DDA, in L-B films, a 233

layered conducting/Pt, a 35 + RuO,, in electron detector, a 39 Potassium 41, 140 Prince of Wales Award for Innovation 20 1 Promoters, 10.11 -dihydrocinchonidine, a 39

Bi, on PdlC, a 40 Ca, K, La, on PdlSiO, catalysts, a 41

109 Mn, V, a 109, 160

43 Propadiene, effect on ethene hydrogenation, a 107 Propan-2-01, for ketone hydrogenation, a 239

Propionaldehyde, hydrogenation, by RuHI(tppts), a 1 12 Propylene, reactions, a 43, 160, 236, 237

43 Pyrimidine Nucleosides, reaction with triflates 160

Quasicrystals, in AI-Rh, -Pd, -Ir, -Os, -Pt, -Ru 21

Platinum Silicides, for H evolution, a

Poisoning, by metal ions, of Pd catalysts, a

Pollution Control, 1991 SAE conference reports

Cr, to Pd/HY catalysts, a

Mo, V, in PdCI, +Keggin-type anions, a

Propene, hydroformylation, a 109

Propylene Glycol, oxidation, a 160 Propylene Glycol Monoacetate, formation, a

Quinolines, a 110

Radioactivity, reprocessing PGM waste Rapid Thermal Processing, for electrical con Rare Earths, new compounds with Ru, a Reed Switches, a Reforming, reactions, a Resistance Thermometers, Pt, stability, a Resistors, Pt, in thermal conductivity meter,

in mine pit, a RuO, thick film, thin film, a thick film, a

Reviews, electrocatalysts for PAFC, a metal complex anti-cancer drugs, a Pd catalysts in industry, a see also Conferences

Rhodium, coatings in reed switches, a compounds, RhGe, enthalpy of formation,

Rh,O,. a

202 tacts, a 46

34 165

39, 236 1 I3

234 113, 235 155, 240

45 46 44

165 a 154

34

Rhodium (conrd.) Page foil, hydrazine decomposition, a I55 oxidation, high temperature, a 34 radioactive, reprocessing 202

Rh/C multilayers. for soft X-ray use. a Rh(1 I I ) , reactions. a 155. 228

39 thin films. a 38

on Ag{001}, Au{OOI), a 230

Rh-Cu, single crystal solidification, a I55 Rh-Pt, Rh-Pt-Au, volatilisation, a 32 Rh-U-In. magnetic, transport properties, a 32

Rhodium Complexes, Cp*Rh, electrochemical reduction, a 36


Rhodium Alloys, Rh-AI quasicrystals 21

Rh(2.4.6-Me ,CbH2) J , a 34 Rh[P(OPh), 1 j [P(OCbH,)(OPh)z I , (I I56 ICp*RhCIl , , electrochemical production, a [Rhll’(L),C1,l+BF, -, films, electrochemical

Royal Commission on Environmental Pollution,

Ruthenium, colloids. of Ru double salt, a

36

properties, a 36

report on diesel exhaust I87 34

compounds, anti-cancer properties, a 46 RuGe. enthalpy of formation, a 154 Ruse, crystal growth, a I55 RuTiSnO, 0 evolution, a 104 LiRuO,, a 36

34 240

230

effect on Fe40Cr steel, a in thick film resistors, a radioactive, reprocessing 202 Ru(0001), thin Cu films on, a Ru-rare earth systems, a 34

Ru-AI quasicrystals 21

Ruthenium Alloys, FeRuGaSi thin films, magnetism, structure, a 155

Ru-Al-Mn-Si, icosahedral, a 23 I Ru-Ni, for OER electrodes, a I06 Ru-Ti, electrochemistry, a I03

Ruthenium Complexes, oxidants 31, 45

Ru organofluorophosphines 86 Ru(bpy),’+, for HI evolution, using pt blues, a 43

luminescence quenching, a 37, 158 Ru(bpy),’+ on Vycor glass, photo properties, a 37 Ru(I1) bipyridine, optical switching, in L-B film, a 23 Ru(II)polypyridines, photo properties, a I05 [Ru(~-C,H,) (CS, ) (PPh3)~l+ . a 156

45 IRuL,(p-(CN)Ru(CN)L,’),l, light to

electricity conversion, a 37 [Ru(bipy),(L-L’)l(PF,), , photolysis, a I05 IRu(bp~) I (CN) 11 I Ru(bpY)(COO)z) I* -.

antenna sensitised, a 37 IRu(bpy),(Vbpy)I’+, copolymers, in L-B

films, a 233 IRu(bpy): + .Hg,CI: -1, preparation,

characterisation, u 158


(Ph, )[RuO, (0Ac)CI ,I. a

IRu(saloph)CI,l-, carbonylations 70 [RuhSH,)(PPh J)(’S,’)l.THF, structure, a 232 [Ru /EDTA-H (CO I carbonylatlons 70

I(TPP)Ru(CO)l.-, reaction with MeI, a I58 [ ( ~ s - C , H , ) L , ~ u N d - ~ ~ l l + , a I02

Ruthenium Oxides, Bi,Ru,O,, reaction with CuO in resistors, a I55

I05 in resistors, a 113, 155, 240 reduction to LiRuO,, a 36

I I3 I06

RuO , , coatings for DSA, a

RuO , /Al, interface properties, a RuO,/C, electrode in alcohol detector, a RuO,, + polymer blends, for back

(C5-Me,)Rh(PMe3)H,, a 156 scattering electron detector, a 39


I R ~ ( ~ P Y ) , ( ~ P ~ ) , - , I ~ + , “ 2 0 , photoproduction, a

IRu(MeL)(CO)(PPh j)z(Cl)l, a [Ru(PPh j ) , (m-CIC H, C0,)CI , I , formation IRu(saloph)CI,l-, carbonylations [RuhSH,)(PPh j)(’S,’)l.THF, structure, u [Ru /EDTA-H (CO I carbonylatlons ~ ( 7 s - C ,H I )Lz RuNd-aT;11+ , a I(TPP)Ru(CO)l.-, reaction with MeI, a

RuO , , coatings for DSA, u in resistors, a 113, reduction to LiRuO,, u

RuO I IAl, interface properties, a RuO,/C, electrode in alcohol detector, u RuO,, + polymer blends, for back

scattering electron detector, a

Ruthenium Oxides, Bi,Ru,O,, reaction with CuO in resistors, a

233 34

I, u 45 70

232 70

102 158

155 105

155, 240 36

I I3 106

39

, 208

158, 200 234, 240

106. 164. 228

Schottky Barrier Detectors, in IR imaging Schottky Barriers, sensors, a Schottky Contacts, preparation, a Schottkv Diodes. a Semiconductors, technology, compared to

Sensors, see Detectors Silacyclobutene, formation, a Silicon, crystals, Pt doped, a

reaction with Pd, a Single Crystals, Pt, for adsorptions, a

Pt{ 100). for chemical reaction

SMSI, in CO, hydrogenation on Rh, a

Sodium Epoxysuccinate, asymmetric

Solar Energy, adsorption using Rh/AI,O,, a Solar Reactor, a Solder, SnlPb temperature cycling with

Solidification, RhCu single crystals, a Sputtering, gas effect, on PtlCo multilayers, a SQUIDS, magnetometry, a

superconductors

monitoring

in PtlAI,O,, PtlTiO,, a

hydrogenolysis, a

PdlAg, a

2

42 228 229 152

188 41

235

162 37 37

165 155 228 101

Stainless Steel, impro&d properties, a Strain Gauges for high temperatures Styrene reactions, a Sulphur, catalyst poison, a

34, 163, 228 65

42, 103, 110. 111, 159, 161, 239 108, 235

39 95

229, 240

particles, a 162

role in catalytic reforming, a Sulphuric Acid, 0 evolution from Superconductors, high temperature 2

YBaCuO, Pt additions to, a Surfactants, to stabilise Rh(0) colloidal

Symposia, see Conferences Synthesis Gas, alcohol, hydrocarbon

synthesis, a 41. 42, 109, 159 for hydroformylations, a 239 production, a 113, 163 reaction on Fischer-Tropsch

catalyst, a 160

Temperature Measurement, a 113, 208 Thermal Conductivity Meter, for coal mines, a 234 Thermocouples, PtRh30lPtRh6, for extreme

conditions, a 1 I3 Thick Films, Pd, in contacts, a 165

Pd/Ag, conductor metallisation, a 165 Pt, for laser power detector, a 158 resistors, a 235, 240

Thin Films, amorphous metals 83 a-IrTa, diffusion barrier, a 46 capacitors, a 112 Cu on Ru(0001), a 230 FeRuGaSi multilayers, structure,

magnetic properties, a 155 Fe-ClAI, O 3 /Fe-Ru multilayers,

electrical restivity, a 23 1

Langmuir-Blodgett. a 102, 233, 234 Pd, disc electrodes, H insertion, a 157

grown by electroless plating, a 38 in sensors, see Detectors interaction with SiGelSi(100). a 229

hydrous oxidelPt, a 102

Page Pd-Ag alloys, conductivity, a 230 Pd-AI, phase formation, a 153 Pd-Co. multilayers. a 234 Pd-Cr strain gauges 65 PdlInP, amorphous phase formation, a I53 Pd,C, -,, preparation, electrical properties, a 101

I12 Pt, Ir, Rh, Ni, Re, grown by OMCVD, a 38 Pt, Rh, Pd, in metallisation systems, a 240

101 PtSi/Si(l00), by codeposition, MBE system. a 240 PtlCo multilayered, magneto-optics, a 112, 152. 228 PtlFe multilayers, magnetism, a 152 PtlGaAs, amorphous phase formation, a 153 Ptlhighly oriented pyrolytic graphite,

annealing, morphology, a 152 PtlMnlSb, multilayered, preparation,

structure, a 228 PtlSiO,, ultrathin, impedance, morphology, a 32 Rh on Au{001}, Ag{001), growth, a 230 RuO, resistors, a 1 I3 see also Membranes YBaCuOlPtNSZlHastelloy, superconducting, a 240

Thiophene, formation from C ,H, , a 236 Tin, a 34, 153 Triflates, reactions, a 160, 161, 238 Trifluoroacetimidoyl Iodides, a 161 Trimethylpentane, 2,2,4-, hydrocracking,

isomerisation, a 159 Triphenylphosphine, oxidation, a 163 Tritium, enrichment of D in giant Pd cluster, a 230

ULSI, barrier metals for, a 240 Uranous Nitrate, production, a 164 Urea, oxidation, on Pt anodes, a 35 USSR, Pt deposits 96 UV, Schottky barrier detector, a 164

Pt, ion beam deposited, a

Pt oxides, growth, characterisation, a

Vanadium, Pd catalyst promoter, a Vehicles, fuel cell propelled, Grove Symp. Vinyl4Pentynoic Acid, 5-, a Vinyl Acetate, P-vinylation, a Vinylation, reactions, a Vinylbromides, B substitution, a Vinylhalogenides, reduction, a Vinylic Cyclopropane, heteroannulation,

Volatilisation, Pt-Rh alloys, a Voltammograms, Pt(l1 I ) . Pt(l10). Pt( 100)

carboannulation, a

surfaces, a

43 209 238 161

43. 161 161 161

43 32

34

Water, low-level moisture generator, a 106 photoreactions, a 43, 105 treatment, pollution control, a 232

Water Gas Shift Readion 70, 110, 163, 164 Wear, characteristics of contacts, a 165 Wires, Ir, plastic deformation 196

I60

143

Ir, Rh, for HCN synthesis, a superconducting 2

X-Rays, mirror construction. a 39

Wollaston, William Hyde, palladium discovery

Zinc Oxide, dielectric, in PtlCo magneto-optics, a 112


PLATINUM METALS REVIEW...ic HC ter WET DIESEL EXHAUST DRY DIESEL EXHAUST Fig. 1 The compositions are...

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Transcript of PLATINUM METALS REVIEW...ic HC ter WET DIESEL EXHAUST DRY DIESEL EXHAUST Fig. 1 The compositions are...