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

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/Cu2O prepared on carbon cloth and exhibited excellent CO2 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 C2H4. And the synergistic effect of Cu(0)‐Cu(I)‐Cu(II) significantly improved the selectivity of the catalyst to C2H4. This paper provided an efficient method to rationally tune the valence state of Cu‐based catalysts to improve CO2 reduction performance. Cu‐based catalysts with tunable valence state were successfully prepared by modulating the preparation conditions. The selectivity of Cu‐based catalyst can be adjusted by adjusting the valence state. The Faraday efficiency of the carbon‐gaseous products of Cu‐2 reached 35.45±3.40 % at an applied potential of −1.66 V vs. RHE, with 23.85±1.18 %, 4.10±0.64 %, and 7.50±1.58 % for C2H4, CO, and CH4, respectively.