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

Abstract

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.