Engineering Surface Oxophilicity of Copper for Electrochemical CO₂ Reduction to Ethanol

Copper-based materials are known for converting CO₂ into deep reduction products via electrochemical reduction reaction (CO₂ RR). As the major multicarbon products (C₂₊ ), ethanol (C₂ H₅ OH) and ethylene (C₂ H₄ ) are believed to share a common oxygenic intermediate according to theoretical studies, while the key factors that bifurcate C₂ H₅ OH and C₂ H₄ pathways on Cu-based catalysts are not fully understood. Here, a surface oxophilicity regulation strategy to enhance C₂ H₅ OH production in CO₂ RR is proposed, demonstrated by a Cu-Sn bimetallic system. Compared with bare Cu catalyst, the Cu-Sn bimetallic catalysts show improved C₂ H₅ OH but suppressed C₂ H₄ selectivity. The experimental results and theoretical calculations demonstrate that the surface oxophilicity of Cu-Sn catalysts plays an important role in steering the protonation of the key oxygenic intermediate and guides the reaction pathways to C₂ H₅ OH. This study provides new insights into the electrocatalyst design for enhanced production of oxygenic products from CO₂ RR by engineering the surface oxophilicity of copper-based catalysts.