3D Ordered Macroporous Cu-Based Multimetallic Alloy Enables Efficient Asymmetric C-C Coupling for Selective CO₂...

The abundant Cu⁰/Cu^δ+ interfaces generated after reconstruction are crucial for promoting the coupling of *CO and *COH intermediates in electrocatalytic CO₂ reduction. However, Cu sites derived from a single metal severely restrict C-C coupling efficiency and product selectivity. Here, the direct regulation of the interfacial microenvironment is reported by constructing a 3D ordered macroporous (3DOM) architecture composed of multimetallic alloy (MMA) on the surface of CuO_x. The designed catalyst exhibits superior Faradic efficiency of 64.1% for electrochemical CO₂ reduction to ethylene at -1.55 V versus RHE under acidic conditions, and stability for over 60 h at 600 mA cm^-2 in a flow cell. In-situ experiments and theoretical simulations reveal that the 3DOM structure enhances the surface electric field, raises the local pH, and accelerates interfacial mass transport. The electronic structure of Cu^δ+ (0<δ<1) sites at multimetallic interfaces is effectively regulated by other metals, inducing electronic heterogeneity and an asymmetric charge distribution on the Cu sites that facilitates asymmetric *CO-*CHO coupling. This work establishes the design principles for Cu-based multimetallic alloy with atomic-level customisation, demonstrating that the precise structural design and electronic structure of Cu^δ+ sites could govern *CO adsorption and hydrogenation pathways, thereby enhancing ethylene selectivity.