1. Development of Catalytic Activity Protocol for Electrochemical
Reduction of Carbon Dioxide
Surya Singh
Centre for the Environment
Indian Institute of Technology Guwahati
Guwahati, Assam – 781 039

2. Presentation Outline
Introduction
Idea behind the work
Development of Protocol
Validation
Results
References

3. Electrochemical Reduction of Carbon Dioxide
Breaches
400 ppm
on May
9th, 2013
Ref U.S. EIA, monthly energy review, Table 1.3, March 2012
Dec. 10-12, 2013
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4. Possible options for the mitigation of excess CO2
Decrease in fossil fuel consumption and other activities which result in CO2 emission
Effective use of technologies to reduce CO2 emission to the atmosphere
Capture CO2 and dump it in geologic or oceanic reservoirs
Utilize CO2 by converting it to either fuels or some other value added products, resulting in two
fold advantages:
a. Reduction in CO2 level
b. Reducing the dependency over conventional non-renewable fossil fuels, thus enhancing
energy security.
Dec. 10-12, 2013
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5. Utilization of CO2 for the production of value added products
(Ref. Viswanathan B., Proc. Ind. Acad. Sci., 70 A (3), 2004)
Dec. 10-12, 2013
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6. Why Electrochemical reduction of Carbon Dioxide ?
 Reactions can be carried
out at ambient temperature
and pressure conditions
 Co-reactant is Water
 Need of electrical energy can
be fulfilled using renewable
energy resources
(Source: Olah et al., JOC Perspective, 74 (2), 2009)
Dec. 10-12, 2013
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7. Electrochemical Reduction of Carbon Dioxide (ERC)
Anode
Cathode
Anode Reaction:
2H2O
4H+ + 2e- + O2
Cathode Reactions:
CO2 + 2H+ + 2eHCOOH
CO2 + 2H+ + 2eCO
+ H2O
CO2 + 6H+ + 6eCH3OH + H2O
CO2 + 8H+ + 8eCH4
+ 2H2O
Dec. 10-12, 2013
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Eo = - 1.23 V vs. SHE
Eo = - 0.225 V vs. SHE
Eo = - 0.103 V vs. SHE
Eo = + 0.031 V vs. SHE
Eo = + 0.169 V vs. SHE
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8. Challenges to overcome
1
2
Activate this thermodynamically stable molecule
The actual electrolysis potential for CO2 reduction is
much more negative than the eq. potential
3
4
Product separation and analysis
5
Dec. 10-12, 2013
Simultaneous production of Hydrogen
Difficult to achieve the selectivity of products
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9. Use of ELECTROCATALYSTS
How to screen an electrocatalyst from
the group of many ?
Dec. 10-12, 2013
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10. Conventional Approach : Cyclic Voltammetry (CV)
Ex. Cu, Sn, CuO etc.
N2 Atmosphere: Aqueous KHCO3
solution, bubbled with N2 - pH 8.5
CO2 Atmosphere: Aqueous KHCO3
solution, saturated with CO2 - pH 7.5
Dec. 10-12, 2013
Ex. Mo2C etc.
Anomaly : Ag, Ni, Co3O4 etc.
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11. Development of Protocol
Dec. 10-12, 2013
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12. Select a probable electrocatalyst for ERC based upon literature and experience
Test its activity towards ERC (aqueous medium)
1st Test: In 0.5 M aqueous KHCO3, saturated with CO2 (pH 7.5)
Get LSV in presence and absence of catalyst
Electrocatalyst may not be
active for ERC
(particularly
in aqueous medium)
NO
YES
Current increased in presence of catalyst
Electrocatalyst may be active for ERC
INFERENCE
Increased current may be due to increased
H+ reduction / CO2 reduction or both
Test the electrocatalyst activity towards H+ reduction
2nd Test: In KOH aqueous solution (pH 7.5)
Get LSV in presence and absence of catalyst
H+
NO
Electrocatalyst is not active for
reduction INFERENCE
Electrocatalyst may be active only
towards ERC
Current increased in presence of catalyst
YES
Electrocatalyst is also active for H+
reduction
INFERENCE
Electrocatalytic activity has to be checked
esp. for CO2 reduction in absence of H+ ion
Test the electrocatalyst activity towards ERC (non aqueous medium)
3rd Test: In DMF, bubbled with CO2 (pH 7.5)
Get LSV in presence and absence of catalyst
Electrocatalyst is inactive for CO2
reduction
NO
Current increased in presence of catalyst
YES
Electrocatalyst may work for ERC
INFERENCE
Full Cell reaction can be attempted

13. Electrocatalysts Selection
Cu
Commercially
Purchased
Dec. 10-12, 2013
CuO
Synthesized
through Aqueous
Precipitation
method
Co3O4
Synthesized
through Polymer
Combustion
Route
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ZnO
Synthesized
through Aqueous
Precipitation
method
Mo2C
Commercially
Purchased
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14. Characterization of the Electrocatalysts - XRD
ZnO
CuO
Mo2C
Dec. 10-12, 2013
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Co3O4
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15. Characterization of the Electrocatalysts - FESEM
CuO
Mo2C
Dec. 10-12, 2013
ZnO
Co3O4
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16. Characterization of the Electrocatalysts – EDX & FTIR
CuO
Co3O4
Dec. 10-12, 2013
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ZnO
Co3O4
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17. Characterization of the Electrocatalysts – BET surface area

9.9 m2/g

ZnO
15.9 m2/g

Mo2C
5.8 m2/g

Dec. 10-12, 2013
CuO
Co3O4
9.2 m2/g
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18. ‘Cyclic Voltammetry’ tests using selected electrocatalysts
Cu
Mo2C
ZnO
CuO
Dec. 10-12, 2013
Co3O4
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19. ‘Protocol Results’ using selected
electrocatalysts
Protocol
Results
Electrocatalysts
1st Test (% j)
2nd Test (% j)
3rd Test (% j)
Cu
Yes (146)
Yes (38)
Yes (52)
CuO
Yes (21)
Yes (13)
Yes (32)
ZnO
Yes (19)
Yes (18)
Yes (20)
Mo2C
No (~ 0)
Not Applicable
No (~ 0)
Co3O4
Yes (28)
Yes (21)
Yes (45)
1st Test: CO2 sat. Aq. KHCO3 solution
2nd Test: KOH solution
3rd Test: CO2 bubbled DMF
( j denotes the current density)
Dec. 10-12, 2013
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20. Comparison of the results of Proposed Protocol with CV test
Activity of Electrocatalysts
Electrocatalysts
CV
Cu
√
√
CuO
√
√
ZnO
~
√
Mo2C
X
X
Co3O4
Dec. 10-12, 2013
Proposed Protocol
X
√
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21. Full Cell Reaction using electrocatalysts
CO2 saturated
aq. KHCO3
Water
inlet
Gas chromatography (GC)
Cathode
Anode
High performance liquid
chromatography (HPLC)
Cathode
outlet
O2, H2O
outlet
Electrocatalysts
Electrolyte
Product
Yield (%)
CuO
Nafion
Methanol
8.7 %
ZnO
Nafion
Methanol
5.4%
Co3O4
Nafion
Formaldehyde
1.78%
Dec. 10-12, 2013
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22. Summary
Objective
The problem in quick
selection
of
an
electrocatalyst from a
group of many, was
identified as a major
issue in the field of
electrochemical
reduction of carbon
dioxide
Dec. 10-12, 2013
Protocol Development
A new protocol has been
developed for the quick
screening
of
electrocatalysts.
Validation
Results
Various electrocatalysts
were selected to validate
the protocol.
The protocol was
found valid for all the
electrocatalysts tested.
Electrocatalysts
were
characterized
physicochemically.
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23. Acknowledgements
 First and Foremost thanks to my supervisors Dr. Anil Verma & Dr. Chandan Mukherjee for
their sagacious guidance, suggestions and sustained encouragement.
 Thanks to the National Program on Carbon Sequestration Research, DST, New Delhi for the
financial support vide project grant number DST/IS-STAC/CO2-SR-139/12(G).
 Heartful gratitude to my research group members:
•
•
•
•
•
•
Ms. Lepakshi Barbora
Mr. Avijit Ghosh
Mr. Leela M. Aeshala
Mr. V. Shyam K. Yadav
Mr. Ehtesham Hussain
Mr. Rajamahendra Rapally

24. Thank You!!