Enhanced interfacial effect-induced asymmetric coupling boost electroreduction of CO2 to ethylene

Electroreduction of CO₂ to C₂H₄ is a promising strategy for carbon neutralization. However, the kinetic challenge of *CO dimerization, particularly at high current-density, limits its suitability for industrial production. Here, we report that Cu/Ag bimetallic catalyst (Cu₅₂Ag₄₈) with strong interfacial effect can promote high C₂H₄ selectivity at high current-density. We find that the elaborately designed Cu/Ag interface not only inhibits HER and ethanol formation by weakening H adsorption, but also promotes the formation of *CHO intermediates, achieving an unusual asymmetric *CO-*CHO coupling instead of the common symmertic *CO-*CO coupling. Subsequently, the Faradaic efficiency of C₂H₄ over Cu₅₂Ag₄₈ is significantly increased to 69.2% at a high current-density of up to 450 mA cm⁻². The interfacial effect-induced *CO-*CHO coupling can be extended to other metals with weak H and O adsorption such as Cu/Zn and Cu/Au, thereby boosting the production of C₂H₄ in CO₂RR.