Operando Reconstruction of Porous Carbon Supported Copper Selenide Promotes the C2 Production from CO2RR

Abstract Precisely regulating surface reconstruction of copper (Cu) chalcogenides‐based catalysts to promote the multicarbon (C 2+ )selectivity of the electrochemical CO 2 reduction reaction (CO 2 RR) is hampered by the challenging control of the intractable anions and the optimal Cu δ+ reduction (0 < δ < 1). Herein, a porous carbon‐supported copper selenides electrocatalyst that can remarkably improve the C 2 ‐product yield and especially unveil the time‐revolved electrochemical CO 2 RR reconstruction process to enable the high C 2 ‐selectivity, most notably for ethanol is constructed. The Faradic efficiency (FE) of C 2 ‐products achieved is as high as ≈85.2% with a partial current density of 229.5 mA cm −2 . Operando infrared spectroscopy and density functional theory (DFT) calculations unravel that the surface Se vacancies ( V Se ) formation brings closer the neighboring Cu + atoms and activates the Cu sites, thereby rendering efficient generation of the key intermediates ( * CO and * CHO) and lowering the C–C coupling barrier for C 2 production. The appearance of metallic Cu can shorten the next‐nearest Cu 0 –Cu + distance for O atom to bridge in, leading to the preferential formation of * OC 2 H 4 towards ethanol instead of C–O bond cleavage to form ethylene. This work opens the avenue of designing suitable local atomic structures catalysts to engage the intermediates for targeted CO 2 RR products.