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Updated: Sep 17, 2025
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Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds
Published on: October 12, 2018
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Operando Raman characterization of unique electroinduced molecular tautomerization in zero-gap electrolyzers promotes
Ling Li1,2,3, Wentao Ye1,2,3, Qiliang Liu1,2,3
1Center of Artificial Photosynthesis for Solar Fuels and Research Center for Industries of the Future, Westlake University, Hangzhou, 310024 Zhejiang, China.
Summary
This study reveals electroinduced molecular tautomerization of 4-mercaptopyridine (4MPy) on copper catalysts within membrane electrode assemblies (MEAs). This process significantly enhances electrochemical CO2 reduction reaction (CO2RR) performance.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Membrane electrode assemblies (MEAs) are crucial for electrocatalysis, like CO2 reduction.
- MEAs feature a unique solid-liquid-gas triple-phase interface.
- Understanding interfacial phenomena is key to improving CO2RR.
Purpose of the Study:
- To investigate electroinduced molecular transformations at the MEA triple-phase interface.
- To explore the impact of these transformations on CO2RR performance.
- To elucidate the role of the MEA architecture in enabling specific surface reactions.
Main Methods:
- Utilizing a home-designed MEA-type operando Raman cell for in-situ analysis.
- Performing electrochemical CO2 reduction reactions under high current densities (>100 mA cm-2).
- Comparing MEA performance with traditional flow and H-cell setups.
Main Results:
- Discovered electroinduced thiol to thione tautomerization of 4-mercaptopyridine (4MPy) on Cu catalysts within MEAs.
- Achieved over 80% Faradaic efficiency for C2+ products, with >60% C2H4, and a 300 mV cell voltage reduction.
- Observed that this tautomerization is unique to MEAs, not occurring in flow or H-cells due to electrolyte-induced desorption.
Conclusions:
- Surface molecular tautomerization can be leveraged to significantly boost CO2RR performance.
- The unique triple-phase interface of MEAs can drive specific surface reactions not feasible in other electrolyzers.
- This work opens new avenues for catalyst and device design for enhanced CO2 conversion.
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