Engineering Surface Oxophilicity of Copper for Electrochemical CO 2 Reduction to Ethanol.

Copper-based materials are known for converting CO 2 into deep reduction products via electrochemical reduction reaction (CO 2 RR). As the major multicarbon products (C 2+ ), ethanol (C 2 H 5 OH) and ethylene (C 2 H 4 ) are believed to share a common oxygenic intermediate according to theoretical studies, while the key factors that bifurcate C 2 H 5 OH and C 2 H 4 pathways on Cu-based catalysts are not fully understood. Here, a surface oxophilicity regulation strategy to enhance C 2 H 5 OH production in CO 2 RR is proposed, demonstrated by a Cu-Sn bimetallic system. Compared with bare Cu catalyst, the Cu-Sn bimetallic catalysts show improved C 2 H 5 OH but suppressed C 2 H 4 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 C 2 H 5 OH. This study provides new insights into the electrocatalyst design for enhanced production of oxygenic products from CO 2 RR by engineering the surface oxophilicity of copper-based catalysts.