Electrochemical CO2 reduction to ethylene by ultrathin CuO nanoplate arrays

Electrochemical reduction of CO 2 to multi-carbon fuels and chemical feedstocks is an appealing approach to mitigate excessive CO 2 emissions. However, the reported catalysts always show either a low Faradaic efficiency of the C 2+ product or poor long-term stability. Herein, we report a facile and scalable anodic corrosion method to synthesize oxygen-rich ultrathin CuO nanoplate arrays, which form Cu/Cu 2 O heterogeneous interfaces through self-evolution during electrocatalysis. The catalyst exhibits a high C 2 H 4 Faradaic efficiency of 84.5%, stable electrolysis for ~55 h in a flow cell using a neutral KCl electrolyte, and a full-cell ethylene energy efficiency of 27.6% at 200 mA cm −2 in a membrane electrode assembly electrolyzer. Mechanism analyses reveal that the stable nanostructures, stable Cu/Cu 2 O interfaces, and enhanced adsorption of the *OCCOH intermediate preserve selective and prolonged C 2 H 4 production. The robust and scalable produced catalyst coupled with mild electrolytic conditions facilitates the practical application of electrochemical CO 2 reduction. Oxide-derived copper has been extensively studied as catalysts for CO 2 electroreduction but its catalytic stability and selectivity still need to be improved. Here, the authors report ultrathin CuO nanoplate arrays for CO 2 reduction with high ethylene selectivity and enhanced long-term stability.