Interfacial Tailoring of Graphene‐Cu Heterostructure Boosts CO 2 Electroreduction Toward Ethylene

Electrochemical CO 2 reduction to multicarbon (C 2+ ) products remains limited by sluggish CO 2 activation, inefficient C─C coupling, and competition from the hydrogen evolution reaction. Herein, we report a graphene–copper heterostructure catalyst (Gr@Cu) that significantly enhances ethylene production through rational interfacial electronic modulation. The optimized Gr@Cu 0.8 catalyst achieved a Faradaic efficiency of ~55% for ethylene (C 2 H 4 ) at −0.87 V versus RHE. Density functional theory calculations reveal that interfacial charge transfer at the Gr@Cu interface lowers the energy barriers for both the CO 2 activation and *CO dimerization, thus promoting the key C─C coupling step. Frontier orbital and d‐band center analyses further demonstrate that the heterostructure elevates the Cu d‐band center and improves orbital coupling with reaction intermediates, facilitating electron transfer and intermediate adsorption. This work elucidates the structure–activity relationship of graphene–metal heterointerfaces and provides mechanistic guidelines for designing advanced electrocatalysts toward efficient and selective CO 2 ‐to‐C 2+ conversion.