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

Presentation Outline

Introduction

References

Results

Validation

Development of Protocol

Idea behind the work

Electrochemical Reduction of Carbon Dioxide

Dec. 10-12, 2013 ICAER – 2013 3

Breaches 400

ppm on May 9th,

2013

Ref U.S. EIA, monthly energy review, Table 1.3, March 2012

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.

Possible options for the mitigation of excess CO2

Dec. 10-12, 2013 ICAER – 2013 4

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 ICAER – 2013 5

Dec. 10-12, 2013 ICAER – 2013 6

Why Electrochemical reduction of Carbon Dioxide ?

Reactions can be carried out at ambient temperature and pressure conditions

(Source: Olah et al., JOC Perspective, 74 (2), 2009)

Co-reactant is Water Need of electrical energy can be fulfilled using renewable energy resources

Electrochemical Reduction of Carbon Dioxide (ERC)

Anode Reaction: 2H2O 4H+ + 2e- + O2

Eo = - 1.23 V vs. SHE

Cathode Reactions: CO2 + 2H+ + 2e- HCOOH Eo = - 0.225 V vs. SHE

CO2 + 2H+ + 2e- CO + H2O Eo = - 0.103 V vs. SHE

CO2 + 6H+ + 6e- CH3OH + H2O Eo = + 0.031 V vs. SHE

CO2 + 8H+ + 8e- CH4 + 2H2O Eo = + 0.169 V vs. SHE

Dec. 10-12, 2013 ICAER – 2013 7

Anode Cathode

Dec. 10-12, 2013 ICAER – 2013 8

11 Activate this thermodynamically stable moleculeActivate this thermodynamically stable molecule

44 Product separation and analysisProduct separation and analysis

55 Difficult to achieve the selectivity of productsDifficult to achieve the selectivity of products

Challenges to overcome

33 Simultaneous production of Hydrogen

22 The actual electrolysis potential for CO2 reduction is

much more negative than the eq. potential

How to screen an electrocatalyst from the group

of many ?

Dec. 10-12, 2013 ICAER – 2013 9

Use of ELECTROCATALYSTS

Conventional Approach : Cyclic Voltammetry (CV)

Ex. Cu, Sn, CuO etc.

Dec. 10-12, 2013 ICAER – 2013 10

Anomaly : Ag, Ni, Co3O4 etc.

Ex. Mo2C etc.

N2 Atmosphere: Aqueous KHCO3 solution, bubbled with N2 - pH 8.5

CO2 Atmosphere: Aqueous KHCO3 solution, saturated with CO2 - pH 7.5

Development of Protocol

Dec. 10-12, 2013 ICAER – 2013 11

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

Current increased in presence of catalyst Electrocatalyst may be active for ERCINFERENCE

Increased current may be due to increased H+ reduction / CO2 reduction or both

Electrocatalyst may not be active for ERC (particularly in aqueous medium)

YESNO

Electrocatalyst is also active for H+ reductionElectrocatalyst is not active for H+

reductionElectrocatalyst may be active only

towards ERCElectrocatalytic activity has to be checked esp. for CO2 reduction in absence of H+ ion

YES

Test the electrocatalyst activity towards H+ reduction

2nd Test: In KOH aqueous solution (pH 7.5)

Get LSV in presence and absence of catalyst

Current increased in presence of catalystNO

INFERENCE INFERENCE

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

Current increased in presence of catalyst Electrocatalyst may work for ERC

Full Cell reaction can be attempted

Electrocatalyst is inactive for CO2 reduction

YESINFERENCE

NO

Synthesized through Aqueous

Precipitation method

Synthesized through Polymer

Combustion Route

Commercially Purchased

Synthesized through Aqueous

Precipitation method

Commercially Purchased

Cu CuO Co3O4 ZnO Mo2C

Electrocatalysts Selection

Dec. 10-12, 2013 ICAER – 2013 13

Characterization of the Electrocatalysts - XRD

CuO ZnO

Co3O4Mo2C

Dec. 10-12, 2013 ICAER – 2013 14

Dec. 10-12, 2013 ICAER – 2013 15

Characterization of the Electrocatalysts - FESEM

CuO ZnO

Co3O4Mo2C

Characterization of the Electrocatalysts – EDX & FTIR

CuO ZnO

Co3O4

Dec. 10-12, 2013 ICAER – 2013 16

Co3O4

Characterization of the Electrocatalysts – BET surface area

Dec. 10-12, 2013 ICAER – 2013 17

CuO

ZnO

Mo2C

Co3O4

9.9 m2/g

15.9 m2/g

5.8 m2/g

9.2 m2/g

Dec. 10-12, 2013 ICAER – 2013 18

CuO

ZnO

Mo2CCu

Co3O4

‘Cyclic Voltammetry’ tests using selected electrocatalysts

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)

Protocol Results

Dec. 10-12, 2013 ICAER – 2013 19

‘Protocol Results’ using selected electrocatalysts

( j denotes the current density)

1st Test: CO2 sat. Aq. KHCO3 solution2nd Test: KOH solution3rd Test: CO2 bubbled DMF

Electrocatalysts

Cu

CuO

ZnO

Mo2C

Activity of Electrocatalysts

CV Proposed Protocol

Co3O4

X X

X

√

√√

√

~

√

√

Comparison of the results of Proposed Protocol with CV test

Dec. 10-12, 2013 ICAER – 2013 20

CO2 saturated aq. KHCO3

Water inlet

O2, H2O outlet

Cathode outlet

AnodeCathode

Full Cell Reaction using electrocatalysts

Dec. 10-12, 2013 ICAER – 2013 21

Electrocatalyst

s

Electrolyte Product Yield (%)

CuO Nafion Methanol 8.7 %

ZnO Nafion Methanol 5.4%

Co3O4Nafion Formaldehyde 1.78%

Gas chromatography (GC)

High performance liquid chromatography (HPLC)

A new protocol has been developed for the quick screening of electrocatalysts.

Various electrocatalysts were selected to validate the protocol.

Electrocatalysts were characterized physico-chemically.

The protocol was found valid for all the electrocatalysts tested.

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

Objective Protocol Development

Validation Results

Summary

Dec. 10-12, 2013 ICAER – 2013 22

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

Thank You!!