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

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.

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/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.

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