Metal–Oxide Interfaces for Selective Electrochemical C–C Coupling Reactions

Metal–oxide interfaces provide a new opportunity to improve catalytic activity based on electronic and chemical interactions at the interface. Constructing a high density of interfaces is essential in maximizing synergistic interactions. Here, we demonstrate that Cu–ceria interfaces made by sintering nanocrystals facilitate C–C coupling reactions in electrochemical reduction of CO2. The Cu/ceria catalyst enhances the selectivity of ethylene and ethanol production with the suppression of H2 evolution in comparison with Cu catalysts. The intrinsic activity for ethylene production is enhanced by decreasing the atomic ratio of Cu/Ce, revealing the Cu atoms near ceria are an active site for C–C coupling reactions. The ceria is proposed to weaken the hydrogen binding energy of adjacent Cu sites and stabilize an *OCCO intermediate via an additional chemical interaction with an oxygen atom of the *OCCO. This work offers new insights into the role of the metal–oxide interface in the electrochemical reduction of CO2 to high-value chemicals.