Challenge the future

DelftUniversity ofTechnology

From CO2 and H2O to HydrocarbonsElectrocatalytic Reduction at Copper Plate Electrodes

Christa Ros, Patricia Kooyman, Guido Mul, Freek Kapteijn

Catalysis Engineering – ChemE

2 | 23

The problem – part 1

Available:

Use: =

~ 60000 BBL/day

depleted in ~40 years

Het olielek in de Golf van Mexico is ongeveer veertien keer groter dan de schatting van BP. Dat blijkt uit geavanceerde berekeningen en computeranalyses aan drie Amerikaanse universiteiten. Eerst meldde BP dat 110.00 liter lekte per dag, dat werd na een paar dagen 150.000 en vorige week werd het cijfer naar 800.000 liter per dag gezet. Wetenschappers van Purdue, University of California Berkeley en Columbia University zeggen nu dat ze uitgerekend hebben dat het 11 miljoen liter per dag is.

http://www.boston.com/bigpicture/2010/05/disaster_unfolds_slowly_in_the.html

https://www.cia.gov/library/publications/the-world-factbook/rankorder/2178rank.htmlhttps://www.cia.gov/library/publications/the-world-factbook/rankorder/2174rank.html

1.37*1012 BBL9.87*107 BBL/day3.60*1010 BBL/year

Availability of crude oil

(2009)(2008)

3 | 23http://zfacts.com/p/

194.htmlhttp://zfacts.com/p/226.html

The problem – part 2CO2 emissions

4 | 23

Project Aims

• CO2 + H2O HC’s (electrocatalytic)• Understand the influence of Cu morphology, purity, and

oxidation state on performance• Control the productivity of electrodes for the

electrocatalytic reduction of CO2.

• Control the selectivity towards higher hydrocarbons (Fischer-Tropsch-like products).

• Optimize the reactor configuration for high yields of products.

• Prevent deactivation of the electrodes.

Cu

5 | 23

TheoryThe Overall Reaction

E2 2 x 2y 2xCO +yH O C H + x+0.5y O

Aim:Convert carbon dioxide and water into

hydrocarbons and oxygen.

We need energy for this process

6 | 23

TheoryPossible Energy Supplies

Directly from Sunlight External Energy Sourcewindmills, water tide etc.

7 | 23

Electrocatalytic Reaction

Platinum plate

2 H2O O2 + 4H+ + 4e-

Copper plate

CO2 + 8H+ + 8e- CH4 + 2H2O

2CO2 + 12H+ +12e- C2H4 + 4H2O

3CO2 + 18H+ + 18e- C3H6 + 6H2O

Gas inlet

e-

CO2 + H+

CxHy + H2O

H2O

O2 + H+

e-

CO2H+

K+

CO2

H+

CO2

H+

CO2

H+

K+

H+

H+

H+

Reaction conditions• Reactor Batch• Solution 0.1 M KHCO3 sat. CO2

• Electrode WE: Copper PlateCE: PlatinumRE : Ag/AgCl

• Potentiostatic operation @ -1.65V• Temperature 220C• Gas Sampling every 25-30 min

8 | 23

Progress

• It is possible to convert CO2 and H2O into hydrocarbons.

• Influence of surface morphology on productivity and selectivity.

• Controlled copper-electrode production by electro-deposition.

• The importance of reactor design in electro-chemistry.

9 | 23

0 5 10 15 20

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

4.095

5.55

6.311.235

11.67

17.38518.3

Co

un

ts [-]

Time [min]

ExperimentTypical Gas Chromatogram

CH4

C2H4

C2H

6

C3H

6

C3H

4 C4H8

?

C4H1

0

it is possible to convert carbon dioxide and water into hydrocarbons

hydrocarbons up to C4 can be seen from electrocatalytic reduction

Bart v.d Linde + Kevin Mouthaan

10 | 23

ExperimentBare Cu-plates of different suppliers

0

2

4

6

8

10

12

14

16

18

Met

hane

Ethyle

ne

Ethan

e

Met

hylace

tylen

e

Propy

lene

Propa

ne

Butan

e

Co

nce

ntr

atio

n [

*10

-8 m

ol /

(L

* c

m2)]

GF 99.9% A

GF 99.9% H

AA 99.9%

GF 99.99%

AA 99.9999%

GF 99.9% A

GF 99.9% H

AA 99.9%

GF 99.99%

AA 99.9999%

Different supplier gives

another activity and

selectivity

Surfaces do look slightly different

for copper plates of different

suppliers

11 | 23

Surface structure before CO2 reduction

• Starting material is very smooth in all cases• Small differences can be seen

methane

ethylene

Is not an explanation for ratio methane/ethylene

GF 99.9% A GF 99.9% H AA 99.9% GF 99.99% AA 99.9999%

1μm 1μm 1μm 1μm 1μm

11.1M/E: 4.9 1.9 5.3 1.6 1.0 0.5 12.9 0.8 0.9

SEM pictures: Kees Kwakernaak (3ME)

12 | 23

Surface structure after CO2 reduction

• Rough surface ethylene• Smooth surface methane

methane concentration ethylene concentrationM/E =

Before CO2 reduction

1μm

After CO2 reduction

M/E: 0.5 M/E: 12.91μm 1μm

Correlation between surface morphology and product formation

Kasper Kuijpers (BSc)

13 | 23

Progress

• It is possible to convert CO2 and H2O into hydrocarbons.

• Influence of surface morphology on productivity and selectivity.

• Controlled copper-electrode production by electro-deposition.

• The importance of reactor design in electro-chemistry.

14 | 23

Copper deposition

Gas inlet

e-

Cu2+

Cu (s)

Cu (s)

Cu2+

e-

SO42-H+

Cu2+

SO42-

Cu2+

SO42-

H+

SO42-

H+

Cu2+

Cu2+

Cu2+

H+

Reaction conditions• Reactor Batch• Solution 0.14M CuSO4

0 – 0.86M H2SO4

0 – 0.86M NaCl• Time 15 minutes• Galvanostatic operation @ 100mA• Temperature 220C

Copper plate

Cu2+ + 2e- Cu

Copper plate

Cu Cu2+ + 2e-

15 | 23

Results electro-deposition Cu on Cu

0M H2SO4

0.29M H2SO4

0.58M H2SO4

0.86M H2SO4

0M NaCl 0.3M NaCl 0.86M NaCl

• 0M NaCl:[H2SO4] part. size

(cluster formation for conc. > 0.5M)

• 0.3M NaCl:[H2SO4] porosity

• 0.29M H2SO4:

[NaCl] part. size

At high NaCl concentrations,

CuCl is formed. The samples

are rinsed with NH3 to

remove the CuCl.

Different particle sizes and surface

porosities can be obtained by playing

around with the NaCl and H2SO4 concentrations.

Jarno Timmermans (MSc)

16 | 23

Results CO2 reduction reaction

0 100 200 300 400 500

0.0

0.2

0.4

0.6

0.8

1.0

Co

nce

ntr

atio

n [

mo

l/(L

*cm

2 )]

Time [min]

0 100 200 300 400 500

0.000

0.025

0.050

0.075

0.100

Co

nce

ntr

atio

n [

mo

l/(L

*cm

2)]

Time [min]

Methane 0.064 0.044 0.004

Ethylene 0.537 0.438 1.008

Ethane 0.009 0.001 0.089

Total (%) 0.6 0.5 1.1

Faraday Efficiency = n*Na*c*A*V / (I*t/e)

Rougher surface lowers methane formation and increases C2-production.

Bare 0.29M H2SO4

0M NaCl

0.29M H2SO4

0.3M NaCl

1 2 3

Ethylene

1

2

3

1

2

3

1,23

Methane

Ethane

17 | 23

Progress

• It is possible to convert CO2 and H2O into hydrocarbons.

• Influence of surface morphology on productivity and selectivity.

• Controlled copper-electrode production by electro-deposition.

• The importance of reactor design in electro-chemistry.

18 | 23

Reactor design

Issues:• Sample size

• Distance between electrodes

• External reference electrode

• Stability Potentiostat

Improvements:• Fixed sample size

• Fixed distance between

electrodes

• R.E. in direct contact with liquid

• New versatile potentiostat

0 100 200 300 400 500 6000.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

Co

nce

ntr

atio

n [

um

ol/(

L*c

m2

)]

Time [min]

C=C

CH4

0 100 200 300 400 5000.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

C-C

C=C-C

Con

cent

ratio

n [

mol

/(L*

cm2)]

Time [min]

C=C

CH4

19 | 23

Reactor design - stirring

0 100 200 300 400 500

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Con

cent

ratio

n [

mol

/(L*

cm2 )

]

Time [min]

Stirring enhances mass transport (gas bubbles)

Ethylene

No stirringStirring

20 | 23

Reactor design – sample holder

0 100 200 300 400 500

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Con

cent

ratio

n [

mol

/(L*c

m2 )

]

Time [min]

Ethylene

Methane

Shape of sample holder influences mass transport

Old holderNew

holder

21 | 23

Reactor design - stirring

0 100 200 300 400 500

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Con

cent

ratio

n [

mol

/(L*c

m2 )

]

Time [min]

Ethylene

Methane

High flow speed creates a vortex

decreases mass transport H+-ions

Small

stirrerLarge stirrer

22 | 23

H2, CO and Liquid products

• GC column that can handle HC’s and separates H2 and CO

• Liquid products: MS or HPLC

0 5 10 15 20 25 300.0

2.0x1011

4.0x1011

6.0x1011

8.0x1011

1.0x1012

Propionic Acid

Propanol

Acetic Acid

Methanol

Formic Acid

Ethanol

Formaldehyde

Inte

nsity

Time [min]

MS: Erik Kalshoven (pfeiffer) HPLC: Emmanuel Skupien / Maarten

Gorseling

23 | 23

SummaryTwo-phase reactor Three-phase reactor

old new

Bare Copper Electrodeposited Copper

Carbon nanofibers deposited with Copper

CuOCu2O

Renaldo van Rijswoud (MSc)

Dennis Mos (BSc)Kasper Kuijpers (BSc) + Jarno Timmermans (MSc)

24 | 23

25 | 23

200 400 600 800 10000

5000 After B

After A

Raman shift [cm-1]

Before

Surface material

Hamilton e.a. J. Electrochem. Soc 133 (1986) 739-745

Before

After A

After B

Cu2O Cu2O Cu2O Cu2O

CuO

1μm

1μm

1μm

CuO

Cu2O

CuO

Cu2O

26 | 23

Faraday Efficiency

Faraday Efficiency = n*Na*c*A*V / (I*t/e)

-5 mA -15.7 mA

Methane 0.677 15.391

Ethylene 2.273 6.963

Ethane 0.079 0.426

Methyl acetylene

0.017 0.022

Propylene 0.122 0.079

Total 3.167 22.880

n: # electrons A: surface area [cm2]Na: number of Avogadro V: Gas volume [L]c: concentration [mol/cm2/L] I: current [A]e: # electrons / coulomb t: reaction time [sec]

27 | 23

Copper Electrode

Electrochemical Reaction•Bare Copper Plates•Electrodeposited plates

(AA 99.9% or Carbon as substrate)•Etched Copper plates

(H3PO4, 2.400 V, 1 min)

•Copper Mesh•Carbon Nanofibers

Copper Material•Good Fellow

• 99.9% Annealed • 99.9% Half Hard• 99.99% As Rolled

• Alfa Aesar• 99.9%• 99.9999%

28 | 23

ResultsEffect of Temperature

0

2

4

6

8

10

12

14

16

18

Met

hane

Ethyle

ne

Ethan

e

Met

hylace

tylen

e

Propy

lene

Propa

ne

Butan

e

Co

nce

ntr

atio

n [

*10

-8 m

ol /

(L

* c

m2)]

GF 99.9% A

GF 99.9% H

AA 99.9%

GF 99.99%

AA 99.9999%

Bare Cu-plates @ 220C Bare Cu-plates @ 450C

Carrying out the experiment at a higher temperature decreases the ethylene production drastically.

0

0.1

0.2

0.3

0.4

0.5

0.6

Co

nce

ntr

atio

n [

*10

-8 m

ol /

(L

* c

m2)]

GF 99.9% A

GF 99.9% H

AA 99.9%

GF 99.99%

AA 99.9999%

The product distribution depends on process conditions.

29 | 23

ResultsTotal Hydrocarbon Production

• Etching the Cu-plates gives different

results for the different Cu-plates.

• There is no direct relation between

surface roughness and total production of

hydrocarbons.

• Increasing the temperature decreases

the total production of hydrocarbons.

• The total hydrocarbon production

depends on process and catalyst

conditions.

0

2

4

6

8

10

12

14

16

18

GF 99.9% A GF 99.9% H AA 99.9% GF 99.99% AA 99.9999%

Co

nce

ntr

atio

n [

*10

-8 m

ol /

(L

* c

m2)]

Bare 22 degrees

Bare 45 degrees

Etched 22 degrees

Etched 45 degrees

30 | 23

Bare spent comparisonAA 99.9999% AA 99.9% GF 99.9% H

C1s

AA 99.9999%AA 99.9%

GF 99.9% H

O1s

AA 99.9999%

AA 99.9%

GF 99.9% H

0 100 200 300 400 5000.0

0.1

0.2

0.3

0.4

0.5

0.6

0 100 200 300 400 5000

1

2

3

4

5

6

Co

nce

ntr

atio

n [

*10-8

mo

l/(L

*cm

2)]

Time [min]

C=C

C-C

CC-C

C=C-C

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2)]

Time [min]

CH4

0 100 200 300 400 500 6000.0

0.5

1.0

1.5

2.0

0 100 200 300 400 500 6000

2

4

6

8

10

12

Con

cent

ratio

n [*

10-8 m

ol/(

L*cm

2)]

Time [min]

C=C

CH4

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2)]

Time [min]

CH4

C-C-C-C

C-C

CC-C

C=C-C

0 100 200 300 400 5000.00

0.05

0.10

0.15

0.20

0.25

0 100 200 300 400 5000.00

0.25

0.50

0.75

1.00

1.25

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2 )]

Time [min]

C=C

CH4

C-C-C-C

C-C

CC-CC=C-C

Con

cent

ratio

n [*

10-8 m

ol/(

L*cm

2)]

Time [min]

CH4

• SEM: Crystal formation in all cases

Size ~ 0.5 μm• Catalysis: linear increase for product formed over time (constant reaction speed)

• XPS: Two oxygen peaks shown • XPS: No difference in carbon amount

31 | 23

Etched spent comparison

• SEM: Crystal formation in 2 out of 3 cases

Size ~ 0.2 μm

AA 99.9999% AA 99.9% GF 99.9% H

AA 99.9999%AA 99.9%

GF 99.9% H

C1s

O1s

AA 99.9999%

AA 99.9%

GF 99.9% H

0 100 200 300 400 5000.0

0.2

0.4

0.6

0.8

1.0

C-C-C-CC-C

CC-C

C=C-C

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2)]

Time [min]

C=C

CH4

0 100 200 300 400 5000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

C-C-C-CC-C

C=C-C

Con

cen

trat

ion

[*10

-8 m

ol/(

L*cm

2)]

Time [min]

C=C

CH4

C-C-C

0 100 200 300 400 5000.0

0.5

1.0

1.5

2.0

2.5

3.0

C-C-C-CC-C

CC-C

C=C-C

Con

cent

ratio

n [*

10-8 m

ol/(

L*cm

2)]

Time [min]

C=C

CH4

• Catalysis: linear increase for almost all product formed over time (constant reaction speed). • Exception for C=C

• XPS: Two oxygen peaks shown • XPS: No difference in carbon amount

32 | 23

GF 99.9%H

0 100 200 300 400 5000.0

0.5

1.0

1.5

2.0

2.5

3.0

C-C-C-CC-C

CC-C

C=C-C

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2)]

Time [min]

C=C

CH4

0 100 200 300 400 5000.00

0.05

0.10

0.15

0.20

0.25

0 100 200 300 400 5000.00

0.25

0.50

0.75

1.00

1.25

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2)]

Time [min]

C=C

CH4

C-C-C-C

C-C

CC-CC=C-C

Co

nce

ntr

atio

n [*

10

-8 m

ol/(

L*c

m2)]

Time [min]

CH4

SEM before

SEM after

SEM before

SEM after

0

0.5

1

1.5

2

2.5

3

C C=C C-C C≡C-C C=C-C C-C-C C-C-C-C

Co

nce

ntr

atio

n [*

10-8

mo

l / (

L *

cm

2 )]

Bare

Etched

Bare

Etched

33 | 23

Why Copper?

[Hori, Y. et al., NEDO-GET-9208, 1993, 31]