Interface-Regulated Orbital Coupling Enables Nucleophilic Carbon Assembly Pathways in Electrochemical CO₂ Conversion

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Selective electroreduction of carbon dioxide (CO2) to ethanol is crucial for sustainable chemical production.
• Challenges include copper (Cu) oxidation state instability and inefficient carbon-carbon (C-C) coupling during the reaction.

Purpose of the Study:

• To develop a stable and selective catalyst for CO2 electroreduction to ethanol.
• To elucidate the mechanism of enhanced C-C coupling and ethanol selectivity.

Main Methods:

• Fabrication of a zinc (Zn) single-atom-copper oxide (Cu2O) hybrid catalyst.
• Electrochemical performance testing for ethanol Faradaic efficiency and durability.
• Density functional theory (DFT) calculations and operando X-ray absorption spectroscopy (XAS) for mechanistic studies.

Main Results:

• The Zn single-atom-Cu2O catalyst achieved a high ethanol Faradaic efficiency of 74.4% with stable operation for 200 hours.
• DFT and operando XAS revealed orbital coupling between Zn and O, inducing interfacial polarization.
• This polarization stabilized active Cu+ sites and facilitated CHO formation, enabling a nucleophilic C-C coupling pathway.

Conclusions:

• The developed catalyst effectively stabilizes Cu+ sites and promotes C-C coupling via interfacial orbital regulation.
• This strategy provides a general approach for designing catalysts for multi-electron reactions and C-X bond formation in electrochemical carbon valorization.