In-situ constructed Cu/CuNC interfaces for low-overpotential reduction of CO₂ to ethanol

Electrochemical CO₂ reduction (ECR) to high-value multi-carbon (C₂₊) products is critical to sustainable energy conversion, yet the high energy barrier of C-C coupling causes catalysts to suffer high overpotential and low selectivity toward specific liquid C₂₊ products. Here, the electronically asymmetric Cu-Cu/Cu-N-C (Cu/CuNC) interface site is found, by theoretical calculations, to enhance the adsorption of *CO intermediates and decrease the reaction barrier of C-C coupling in ECR, enabling efficient C-C coupling at low overpotential. The catalyst consisting of high-density Cu/CuNC interface sites (noted as ER-Cu/CuNC) is then accordingly designed and constructed in situ on the high-loading Cu-N-C single atomic catalysts. Systematical experiments corroborate the theoretical prediction that the ER-Cu/CuNC boosts electrocatalytic CO₂-to-ethanol conversion with a Faradaic efficiency toward C₂₊ of 60.3% (FE_ethanol of 55%) at a low overpotential of -0.35 V. These findings provide new insights and an attractive approach to creating electronically asymmetric dual sites for efficient conversion of CO₂ to C₂₊ products.