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 (CO2RR). As the major multicarbon products (C2+), ethanol (C2H5OH) and ethylene (C2H4) are believed to share a common oxygenic intermediate according to theoretical studies, while the key factors that bifurcate C2H5OH and C2H4 pathways on Cu-based catalysts are not fully understood. Here, a surface oxophilicity regulation strategy to enhance C2H5OH production in CO2RR is proposed, demonstrated by a Cu-Sn bimetallic system. Compared with bare Cu catalyst, the Cu-Sn bimetallic catalysts show improved C2H5OH but suppressed C2H4 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 C2H5OH. This study provides new insights into the electrocatalyst design for enhanced production of oxygenic products from CO2RR by engineering the surface oxophilicity of copper-based catalysts.