Controllable Cu0-Cu+ Sites for Electrocatalytic Reduction of Carbon Dioxide.

Cu-based electrocatalysts can effectively facilitate carbon dioxide electrochemical reduction (CO2ER) 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 supported on copper phyllosilicate lamella to enhance CO2ER performance. Specifically, 20% Cu/CuSiO3 shows the superior CO2ER performance with 51.8% C2H4 Faraday efficiency at -1.1 V vs reversible hydrogen electrode (RHE) during the 6 hours-test. In situ attenuated total reflection infrared spectra and density functional theory calculations were employed to elucidate the reaction mechanism over Cu0-Cu+ sites. The enhancement in CO2ER activity is mainly attributed to the synergistic effect of Cu0-Cu+ pairs: The Cu0 site activates CO2 and facilitates the following electron transfers; while the Cu+ site strengthens the *CO adsorption to further boost C-C coupling. This paper provides an efficient strategy to rationally design Cu-based catalysts with viable valence states to boost CO2ER.