Controllable Cu0‐Cu+ Sites for Electrocatalytic Reduction of Carbon Dioxide

Cu-based electrocatalysts facilitate CO2 electrochemical reduction (CO2 ER) to produce multi-carbon products. However, the roles of Cu0 and Cu+ and the mechanistic understanding remain elusive. This paper describes the controllable construction of Cu0 -Cu+ sites derived from the well-dispersed cupric oxide particles supported on copper phyllosilicate lamella to enhance CO2 ER performance. 20 % Cu/CuSiO3 shows the superior CO2 ER performance with 51.8 % C2 H4 Faraday efficiency at -1.1 V vs reversible hydrogen electrode during the 6 hour test. In situ attenuated total reflection infrared spectra and density functional theory (DFT) calculations were employed to elucidate the reaction mechanism. The enhancement in CO2 ER activity is mainly attributed to the synergism of Cu0 -Cu+ pairs: Cu0 activates CO2 and facilitates the following electron transfers; Cu+ strengthens *CO adsorption to further boost C-C coupling. We provide a strategy to rationally design Cu-based catalysts with viable valence states to boost CO2 ER.