Novel Approach to Non-Precious Metal Catalysts

Novel Approach toNon-Precious Metal Catalysts

Radoslav T. Atanasoski3M CompanyMay 15, 2007

Project ID#: FC 4

2007 DOE HYDROGEN PROGRAM REVIEWMay 15 -18, 2007, Washington, DC

This presentation does not contain any proprietary, confidential, or otherwise restricted information

Overview

Timeline• Project start date: September 1,

2003• Project end date: August 31, 2007• Percent complete: ~95%

Budget• Total Project funding: $3.6 million

- DOE: $2.9 million- Contractor: $0.7 million

• Funding received in FY06: $967 K• Projected funding for FY07: $343 K

Barriers• B. Cost• C. Electrode Performance (Technical targets: See next slide)

Partners/Collaborations• Dalhousie University (subcontractor)

- Prof. J. Dahn; High-throughput catalyst synthesis and basic characterization

• Brookhaven National Lab- Dr. X.-Q. Yang and Dr. W.-S. Yoon; X-Ray

Absorption Spectroscopies • University of Missouri – Kansas City

- Prof. D. Wieliczka; UPS at University of Wisconsin Synchrotron Radiation Center

• INRS-Energie, Materiaux et Telecommunications

- Prof. J-P. Dodelet; EXAFS and UPS characterization of the “model” catalyst

Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 23M

Objectives

Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 3

Goal: Develop new, lower-cost, non-precious metal (NPM) cathode catalysts for replacement of Pt in PEM fuel cells.

Objectives:• Reduce dependence on precious metals (Pt).

• Perform as well as conventional precious metal catalysts currently in use in MEA’s.

• Cost 50% less compared to a target of 0.2 g Pt/peak kW.

• Demonstrate durability of >2000 hours with <10% power degradation.

Non-Pt Catalyst Activity per volume of supported catalyst at 800 mVIR-free

Specific Objectives for 2007 (From last year’s future work slide, FC#12):

Produce new, better-performing more durable catalysts and identify the catalytic sites.

2010 > 130 A/cm3

2015 300 A/cm3

Current DOE Targets:(from HFCIT Multi-Year R&D Plan)

3M

Approach

New materials

Vacuum Nanotechnology

Modeling

Catalyst SynthesisPhysicochemical Characterization

• XPS• XRF• SEM• XRD• Modeling• Ellipsometry• XAS (Brookhaven National Lab)

• SIMS• UPS

Functional Characterization

• Fuel Cell- 50 cm2

(performance and durability)

- Segmented• Gas Diffusion Electrode

• RRDE

• Catalyst synthesis carried out via two complementary and interactive approaches both readily scalable to pilot plant level: Vacuum Processes and Nanotechnology.

• Extensive physicochemical analytical characterization, including modeling work, conducted both at 3M and in collaboration with other institutions when appropriate.

• Functional characterization chiefly performed in 50-cm2 FC; other techniques as required.


• Achieved durability of over 1,000 hours with practically no irreversible performance losses− with comparable, state-of-the-art NPM catalyst activity as reported in

the literature,

− tested at 0.65 V under Hydrogen – Air in 50-cm2 fuel cell.

• Catalytic activity 0.1 A/cm2 at 0.77 V approached the Interim Milestone #5 (0.1 A/cm2 at 0.8 V).

• Fabricated higher surface area, thermally stable substrates for use with the vacuum approach. Achieved activity surpassing the best previous result by a factor of four.

• Made advances in testing, characterization, and modeling that provide valuable feedback for materials development.

Technical Accomplishments



Nanotechnology – Durable Catalyst Support

0 20 40 60 80 100 120 1400.00

0.02

0.04

0.06

0.0875C cell, 30/30 psig, H2/airCF500/500 sccm, coflow.Humidity: 100%/100%

J (A

/cm

2 ) at 0

.6 o

r 0.6

1V

Time at 0.6 or 0.65V (hours)

0 100 200 300 400 500 600 700 800 900 10000.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

75ºC cell, 30/30 psig, 500 sccm H2/500 sccm air, 100%/100%;Current measured at 0.6V from polarization curve after 5 hour hold at 0.65V

FC11925-graph9

J at

0.6

V or

0.6

1V (A

/cm

2 )

Time (hours)

FC11137 FC11138 FC11168 FC11169 FC11909Higher initial performance

More durable (higher Jafter ~66 hours)

Performance of the catalyst supported on dispersed carbon is initially the best but decays rapidly.

Materials different than dispersed carbon, conducting and electrochemically stable in fuel cell environment, were introduced as catalyst support. Performance of these catalysts is very stable and equals the best reported elsewhere. (see next slide)

TiC Support

Higher J after ~ 66 hoursStable performance for > 1,000 hours

Higher initial performance on dispersed carbon

Dispersed Carbon Support

(See Back - up slides for nature of the catalyst)

3M

Under AIR


LANL recently published a paper in Nature detailing a new catalyst, which shows 100 hrs durability. Under similar test conditions, 3M’s catalyst after 1005 hours and LANL’s initial performance are comparable.

Durability – Performance Comparison

0.00 0.02 0.04 0.06 0.08 0.100.4

0.5

0.6

0.7

0.8

0.9

1.0

V (V

olts

)

J (A/cm2)

3M (FC11909, After 1005 hours) LANL

LANL - 5 cm2 cell; 80ºC, 30/30 psig, 300 sccm H2/540 sccm O2, CDP90C/CDP80C; Bashyam and Zelenay, Nature, Vol 443, 7 September 2006, 63, supp. info.3M - 50 cm2 cell; 80ºC cell, 30/30 psig, 560 sccm H2/1000 sccm O2, CDP90C/CDP80C

LANL - 5 cm2 cell; 80ºC, 30/30 psig, 300 sccm H2/540 sccm O2, CDP90ºC/CDP80ºC; Bashyam and Zelenay, Nature, Vol 443, 7 September 2006, 63, supp. info.

3M - 50 cm2 cell; 80ºC cell, 30/30 psig, 560 sccm H2/1000 sccm O2, CDP90ºC/CDP80ºC

3M

Under OXYGEN

Durable Substrate – Surface Area Effect


CVs under NitrogenThe substrate – TiC treated the same way without the catalyst.

The surface area increased by a factor 3 – 4.

The ORR activity in the presence of the catalyst is

orders of magnitude higher.

FC Performance under Oxygen

0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.012

-0.008

-0.004

0.000

0.004

0.008

0.012

I (A

/cm

2 )

E (Volts)

FC11909 - TiC FC11925 - TiC ink sonicated FC12027 - milled TiC FC12056 - BASELINE - TiC fired only (no NA)

Summary_TiC_SiC-graph3

0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

Summary_TiC_SiC-graph4

I (A

/cm

2 )

E (Volts)

FC11909 - TiC FC11925 - TiC ink sonicated FC12027 - milled TiC FC12056 - BASELINE TiC fired (no NA)

3M


Durable Substrate – Voltage StabilityPS held at 1.2V, 1.4V, and 1.5V for 10

minutes; then repeated (1.2V, 1.4V, 1.5V); 75ºC, N2, 132%/132%RH.

0 300 600

10-3

10-2

T ime (Sec)

I (Am

ps/c

m2 )

PS_1.2V_10min_Un2Ch4.corPS_1.4V_10min_Un2Ch4.corPS_1.5V_10min_Un2Ch4.corPS_1.2V_10min_Un2Ch4.corPS_1.4V_10min_Un2Ch4.corPS_1.5V_10min_Un2Ch4.cor

N2 CVs (50 mV/s) – Initial, After 1.2V,1.4V, and 1.5V for 10 min and after additional 10 min at 1.2V, 1.4V, and 1.5V

0 0.2 0.4 0.6 0.8 1.0 1.2-0.4

-0.2

0

0.2

0.4

E (Volts)

I (Am

ps/5

0 cm

2 )

InitialAfter 1.2V, #1After 1.4V, #1After 1.5V, #1After 1.2V, #2After 1.4V, #2After 1.5V, #2

The new substrate material – TiSi – is stable up to 1.4 V. Only after second exposure at 1.5 V, for a total of 20 minutes, considerable surface area effect is observed.

3M


Durability – Other Catalyst PropertiesLarger hydrogen evolution peak (in the N2 CVs) showed greater durability.

N2 CVs (50 mV/s)

0 100 200 300 4000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Nor

mal

ized

Cur

rent

(J/J

initi

al) a

t sta

ted

volta

ge

Time (hours)

FC11909 Normalized FC12178 Normalized FC12245 Normalized FC12172 Normalized

Normalized durability current

0.000 0.005 0.010 0.015 0.020 0.0250.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1-J/Jinit (50hours, 1)

1-J/

J initi

al (5

0 ho

urs

afte

r J/J

i=1)

Intensity of hydrogen evolution peak (A/cm2)

This may point to surface properties of the catalyst that are essential for durability.

0 0.2 0.4 0.6 0.8 1.0 1.2-0.020

-0.016

-0.012

-0.008

-0.004

0

0.004

0.008

0.012

E (Volts)

I (A

mps

/cm

2 )

FC12245FC12172FC11909FC12178

Intensity of H2 evolution peak

Durability

3M


Durability – Peroxide Content

0 0.2 0.4 0.6 0.8 1Potential vs. RHE [V]

-5

-4

-3

-2

-1

0

Dis

k C

urre

nt D

ensi

ty [m

AFa

rada

ic. c

m-2

geom

etri

c]

10

20

30

40

50

60

70

80

90

100%

H2O

2

b)

a)

00-38-1

00-41-2

3M Samples at 900 rpm0.1 M HClO4, room temp

5 mV.s-1, 785μg.cm-2

December 2006

00-38-1

00-41-2

RRDE studies performed on three different catalysts at Dalhousie University.

• Peroxide emission of best performing catalyst on TiCsubstrate is relatively low (< 10%).

• Same peroxide content on the same catalyst made on carbon substrate did not result in durable product.

3M


Thermal Treatment – The Role of Iron

Thermal treatments to 550ºC, 700ºC, and 900ºC in ammonia were performed on three aliquots of the same catalyst batch.

J (m

A/c

m2

) at

0.6

V (

O2

)

252015

30

20

10

0

Treatment Temp (C)

Fe r

edox

(m

A/c

m2

)

1000750500

8

7

6

5

4

Fe (XRF, arb units)

• Performance increases with thermal treatment temperature, NOT THE AMOUNT OF IRON.

•Nearly 1:1 correspondence of Fe content measured via XRF vs the intensity of the Fe redox in the N2 CVs.

• Most Fe remains on the sample treated to 700OC.

3M

Vacuum Processes – New Substrates


• Performance of the new catalyst is significantly better than the best 2006 results from the vacuum approach.

New higher surface area, thermally stable substrates (developed at 3M expense, utilizing 3M proprietary technology) were further improved.

ORR activity of the new substrate with vacuum deposited Fe catalyst

CVs under nitrogen of the new substrate show a large increase in surface area

0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02 2006 Review 2007 Review

I (A

/cm

2 )

E (Volts)

80C Cell, 30/50 psig, CDP80/CDP80;CF180 H2/CF335 O2; CVs at 5 mV/s

0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.006

-0.004

-0.002

0.000

0.002

0.004

I (A

/cm

2 )

E (Volts)

2006 Review 2007 Review

75ºC, 0/0 psig, CF500 H2/CF500 N2, 132%/132%RH

3M


Vacuum Processes – Thermal Treatment

The loss of nitrogen is accompanied by a transition from homogeneity to heterogeneity in the material structure which is reflected on ORR activity as measured by RDE. (Dalhousie University)

E. B. Easton, R. Yang, A. Bonakdarpour, and J. R. Dahn*, Electrochem. and Solid-State Lett., 10 1 B6-B10 2007600 650 700 750 800 850 900 950 1000

Heat-treatment Temperature(oC)

00.40.81.21.6

2

Cur

rent

den

sity

@0.

7V(m

A/c

m2 )

0.50.60.70.80.9

1

Ons

et P

oten

tial

(V v

s.R

HE)

10203040506070

Co

part

icle

siz

e (n

m)

510152025303540

Ato

mic

con

tent

of N

(%)

91011121314

Ato

mic

con

tent

of C

o(%

)

0.1M KOH 0.1M HClO4

0.1M KOH 0.1M HClO4

Nitrogen Loss Heterogeneity

3M

Future WorkRemainder of project:

• Fulfill reporting obligations, most notably the Final report.

• Prepare manuscripts for publication and conference presentations.

• Explore further the area of more durable catalysts substrates and identify the catalytic sites (will continue after completion of the Project).


Summary


• In 2007, a major breakthrough in durability was achieved.

• Overall, the project established new synthetic approachesand opened new avenues for further development in the NPMC world.

• Strong interactive advanced characterization and modeling complement the synthetic effort.

• Strong, fully-integrated collaborations supplement 3M expertise and lead to fundamental understanding of catalyst.

• 12 publications, presentations, and three invited lectures.

• Today, 3M’s catalysts are among the best performing and most durable NPMC tested in a real fuel cell.

Performance ProgressionCurrent at 0.6 V in 50-cm2 FC

0 100 200 300 400 500 600 700 800 900 1000 1100 12000.000

0.004

0.008

0.012

0.016

0.020

0.024

0.028

FC11925-graph4

J at

0.6

V (A

/cm

2 )

Time (hours)

FC11909

Initial performance

Durability

1E-3 0.01 0.1 10.6

0.7

0.8

0.9

1.0 DOE targets calculated assuming same catalystlayer thickness as for the 3M curve shown.

3M: 80ºC cell, 30/50 psig, 100%/100%RHH2/O2; CF180/335 sccm. Pt: 80ºC cell, 7.5/7.5 psig, 100%/100%RH;CS(2.0,139) H 2/CS(9.5,331) O2. Gasteiger et al., Applied Catalysis B: Enviromental 56(2005) 9-35

3M, 19 A/cm3

DOE 2010130 A/cm3

V (V

olts

)

J (A/cm2)

Pt, 0.4 mg/cm2

70 mV/decade

DOE 2015300 A/cm3

DOE 2005 status 8 A/cm3

GM Benchmark Performance

Performance Status

0.01

0.1

1

10

100

1000

9/1/03 8/31/07Timeline

Cur

rent

at 0

.6V

(mA

/cm

2 )

VacuumNanotechnology

3M


Highly Nitrogenated Carbon – HNC – for Acidic FC

• Requires low basicity of nitrogen sites• “Pyridinic” – higher basicity• “Pyrazinic” – lower basicity• Model compounds (Literature values):

N

N

N

N

pKa = 0.37pKa = 1.1N

N

pKa = 0.6

N

NN

pKa = 5.14 pKa = 4.85 pKa = 5.14

N

pKa = 4.52

Catalyst activity depends on the content and the basicity of the N sites:

3M


Thermal Polymerization to Form New HNC

•When iron or cobalt are present, metal is retained as bonded to nitrogen

•Further thermal processing increases conductivity

•Metal cation is used to retain active nitrogen sites (template)

•Metal can be removed with retention/enhancement of activity

•Can titrate sites to examine nitrogen density and basicity

•Supported on nanoparticle support for high surface area

NH2

NO2

NH2 NO2

+Cat.

Δ

NH2

O2N

NH2

O2N+

Cat.

Δ N

NN

Nn

N

N

N

N

N

N

n

(One possible configuration)

Nanoparticle support

Nanoparticle support

3M

Novel Approach to Non-Precious Metal Catalysts

Documents

Transcript of Novel Approach to Non-Precious Metal Catalysts