Manipulating the Oxidation State of Cu_xO Catalysts to Optimize the Selectivity of Gaseous Products in Electrochemical CO₂ Reduction

Abstract Copper‐based (Cu‐based) catalysts can efficiently convert carbon dioxide to multicarbon products by electrochemical reduction. In this paper, the electrocatalyst with the coexistence of three valence states of Cu(0)‐Cu(I)‐Cu(II) was successfully prepared by adjusting the experimental conditions. The catalyst was derived from Cu/Cu 2 O prepared on carbon cloth and exhibited excellent CO 2 reduction performance. For carbon‐gaseous products, the Faradaic efficiencies for the Cu‐2 catalyst consisting of Cu(0)‐Cu(I)‐Cu(II) were 35.45±3.40 % at −1.66 V vs. RHE, of which 23.85±1.18 % for C 2 H 4 . And the synergistic effect of Cu(0)‐Cu(I)‐Cu(II) significantly improved the selectivity of the catalyst to C 2 H 4 . This paper provided an efficient method to rationally tune the valence state of Cu‐based catalysts to improve CO 2 reduction performance.