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

Electrochemical CO 2 reduction reaction (CO 2 RR) offers a promising strategy for CO 2 conversion into value-added C 2+ 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 Cu 0 –Cu + –Cu 2+ sites and oxygen vacancy oxide derived from CeO 2 /CuO nanosheets (OD-CeO 2 /CuO NSs) heterojunction catalysts and promote the activity and selectivity of CO 2 RR. The optimized OD-CeO 2 /CuO electrocatalyst shows the maximum Faradic efficiencies for C 2+ 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 Cu 0 –Cu + –Cu 2+ sites modified with CeO 2 is conducive to CO 2 adsorption and activation, enhances the hydrogenation of *CO to *CHO, and further promotes the dimerization of *CHO, thus promoting the selectivity of C 2+ generation. This facile interface integration and surface reconstruction strategy provides an ideal strategy to guide the design of CO 2 RR electrocatalysts.