In Situ Observation of Post-CO Intermediates to Decode C─C Coupling Pathways in CO₂ Electroreduction.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrocatalytic carbon dioxide reduction (CO2RR) is vital for sustainable energy and carbon utilization.
• Understanding reaction intermediates and pathways for multicarbon (C2+) chemical production remains a challenge.

Purpose of the Study:

• To elucidate the intermediates and C-C coupling mechanisms in CO2RR to C2+ products.
• To enhance in situ observation of elusive intermediates during the reaction.

Main Methods:

• Fabrication of a tailored copper (Cu) nanowire array electrode with a hydrophobic interface.
• In situ Raman spectroscopy for sensitive intermediate detection.
• Density functional theory (DFT) calculations to model reaction pathways.

Main Results:

• Sensitive detection of various intermediates including CO, CH2, CH2CO, and CH3.
• Identification of asymmetric coupling between CH2 and CO to form CH2CO.
• DFT calculations confirmed CH2CO formation as the rate-determining step for C2+ products.

Conclusions:

• The study provides crucial insights into C-C coupling mechanisms in CO2RR.
• Findings advance catalyst development for electrochemical CO2 upgrading to valuable chemicals.