Bottom‐up Growth of Convex Sphere with Adjustable Cu(0)/Cu(I) Interfaces for Effective C2 Production from CO2 Electroreduction

Abstract One challenge confronting the Cu 2 O catalysts in the electrocatalysis of carbon dioxide reduction reaction (CO 2 RR) is the reduction of active Cu(I) species, resulting in low selectivity and quick deactivation. In this study, we for the first time introduce a bottom‐up growth of convex sphere with adjustable Cu(0)/Cu(I) interfaces (Cu x @Cu 2 O convex spheres). Interestingly, the interfaces are dynamically modulated by varying hydrothermal time, thus regulating the conversion of C 1 and C 2 products. In particular, the 4 h hydrothermal treatment applied to Cu 0.25 @Cu 2 O convex sphere with the favorable Cu(0)/Cu(I) interface results in the highest selectivity for C 2 products (90.5 %). In situ Fourier‐transform infrared spectroscopy measurements and density functional theory calculations reveal that the Cu(0)/Cu(I) interface lowers the energy barrier for the production of ethylene and ethanol while increasing the coverage of localized *CO adsorbate for increased dimerization. This work establishes a novel approach for transforming the state of valence‐sensitive electrocatalysts into high‐value energy‐related engineering products.