Highly Ethylene‐Selective Electrocatalytic CO2 Reduction Enabled by Isolated Cu−S Motifs in Metal–Organic Framework Based Precatalysts

摘要

Abstract Copper‐based materials are efficient electrocatalysts for the conversion of CO2 to C2+ products, and most these materials are reconstructed in situ to regenerate active species. It is a challenge to precisely design precatalysts to obtain active sites for the CO2 reduction reaction (CO2RR). Herein, we develop a strategy based on local sulfur doping of a Cu‐based metal–organic framework precatalyst, in which the stable Cu?S motif is dispersed in the framework of HKUST‐1 (S‐HKUST‐1). The precatalyst exhibits a high ethylene selectivity in an H‐type cell with a maximum faradaic efficiency (FE) of 60.0?%, and delivers a current density of 400?mA?cm?2 with an ethylene FE up to 57.2?% in a flow cell. Operando X‐ray absorption results demonstrate that Cuδ+ species stabilized by the Cu?S motif exist in S‐HKUST‐1 during CO2RR. Density functional theory calculations indicate the partially oxidized Cuδ+ at the Cu/CuxSy interface is favorable for coupling of the *CO intermediate due to the modest distance between coupling sites and optimized adsorption energy.