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.