Key to C2 production: selective C-C coupling for electrochemical CO2 reduction on copper alloy surfaces.

The C-C coupling kinetic variations are observed on Cu alloys with Pt, Pd, or Au surface sites. The OC-COH coupling is kinetically more favorable than OC-CHO coupling, which originates from increased reactivity of adsorbed *CO species. Linear energy relations for C-C association/dissociation could simplify the energetic evaluation for C2 production.