Tuning Cu–Cu Spacing in Single‐Atomic Layer Cu Catalysts for Efficient and Stable CO 2 ‐To‐C 2 H 4 Electroreduction

ABSTRACT The transition to sustainable energy relies on the efficient conversion of CO 2 into specific multi‐carbon (C 2+ ) products, yet this process is severely hindered by the slow kinetics of C─C coupling and uncertain product selectivity. Single‐atom catalysts (SACs) exhibit promising catalytic performance but suffer from a fundamental limitation: their lack of contiguous active sites impedes C─C coupling. Herein, we report an innovative isotropic 2D Cu single‐atomic‐layer catalyst anchored on amorphous carbon substrate, designed to enhance C─C coupling and C 2+ selectivity. By stabilizing Cu δ + species and precisely tuning the Cu–Cu spacing to 2.35 Å‐matching the C─C bond length of ethylene (C 2 H 4 ), which significantly promotes C 2 H 4 production. The catalyst achieved a remarkable Faradaic efficiency of 78.6% for C 2 H 4 at −0.8 V versus the reversible hydrogen electrode, accompanied with high stability over 120 h. These findings not only elucidate the profound impact of spatially controlled active sites in complex multi‐step reactions but also represent a significant leap forward in CO 2 conversion technologies, offering great potential for sustainable carbon utilization and addressing global energy transition challenges.