Synergistic modulation of valence state and oxygen vacancy induced by surface reconstruction of the CeO₂/CuO catalyst toward enhanced electrochemical CO₂ reduction

Abstract

Electrochemical CO2 reduction reaction (CO2RR) offers a promising strategy for CO2 conversion into value‐added C2+ products and facilitates the storage of renewable resources under comparatively mild conditions, but still remains a challenge. Herein, we propose the strategy of surface reconstruction and interface integration engineering to construct tuneable Cu0–Cu+–Cu2+ sites and oxygen vacancy oxide derived from CeO2/CuO nanosheets (OD‐CeO2/CuO NSs) heterojunction catalysts and promote the activity and selectivity of CO2RR. The optimized OD‐CeO2/CuO electrocatalyst shows the maximum Faradic efficiencies for C2+ products in the H‐type cell, which reaches 69.8% at −1.25 V versus a reversible hydrogen electrode (RHE). Advanced characterization analysis and density functional theory (DFT) calculations further confirm the fact that the existence of oxygen vacancies and Cu0–Cu+–Cu2+ sites modified with CeO2 is conducive to CO2 adsorption and activation, enhances the hydrogenation of *CO to *CHO, and further promotes the dimerization of *CHO, thus promoting the selectivity of C2+ generation. This facile interface integration and surface reconstruction strategy provides an ideal strategy to guide the design of CO2RR electrocatalysts.