“…Among CO 2 reduction products, C 2 or multicarbon products have received extensive attention due to their higher energy density and application value. Copper (Cu)-based electrocatalysts are the star catalysts that can achieve carbon–carbon (C–C) coupling to generate C 2 or multicarbon products. − Though active site construction, ,,− grain facet/boundary regulation, − defects, ,, and the oxidation state ,, of Cu have been reported to enhance the activity and selectivity of C 2 or multicarbon products, optimizing the surface structure and properties of Cu catalysts to improve the C 2 product efficiency remains a hot topic and challenge. − …”