A derived-Cu catalyst with a potential-driven interface and tensile strain for enhancing CO2 electrocatalytic reduction

The ability to adjust the composition and surface structure of Cu-based nanomaterials is important for designing catalysts to effectively convert CO2 into multi-carbon products via electrocatalytic reduction. Herein we report a potential-driven in situ forming Cu/Cu2O catalyst featuring interface and tensile strain characteristics from the partial reduction of Cu2O nanocubes for electrocatalytic enhancement of the electrochemical CO2 reduction reaction (CO2RR). The results revealed interesting catalytic relationships between Cu+–Cu0 compositions and tensile strain, exhibiting maximum faradaic efficiencies for C2 products in the H-type cell at a Cu0 : Cu+ ratio of ∼46 : 54. As revealed by operando X-ray diffraction analysis, Cu/Cu2O in this ratio exhibits a clear tensile strain in Cu during the CO2RR. The outstanding performance of this composition is attributed to the tensile strain and interface of the surface, in addition to the composition synergy due to the Cu0 sites decorating the surface in an electron-rich state and being conducive to CO2 adsorption and activation and the Cu+ sites enhancing the carbon–carbon coupling to adsorbed *CO, which were also supported by density functional theory (DFT) calculations and in situ ATR-FTIR. The findings open up a new pathway for the rational design of Cu-based catalysts with enhanced activity and selectivity to boost the CO2RR.