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

Precisely regulating surface reconstruction of copper (Cu) chalcogenides-based catalysts to promote the multicarbon (C2+)selectivity of the electrochemical CO2 reduction reaction (CO2RR) is hampered by the challenging control of the intractable anions and the optimal Cu delta+ reduction (0 < delta < 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 CO2RR 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 approximate to 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 *OC2H4 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 CO2RR products.