Dual electronic regulation by carbon interfaces and oxygen vacancies in Cu₂O for selective CO₂ electroreduction to...

Electrochemical CO₂ reduction to valuable multi‑carbon fuels offers a compelling route toward carbon neutrality, yet the selective conversion remains challenging because it requires the coordinated regulation of CO₂ activation, key intermediate hydrogenation, CC coupling, and the competing hydrogen evolution reaction. Herein, we propose a dual electronic regulation strategy by coupling graphene-derived carbon interfaces and oxygen vacancies into Cu₂O to construct a G/Vo-Cu₂O catalyst for selective CO₂ reduction reaction (CO₂RR) toward ethylene. Experimental characterizations and theoretical calculations reveal that the carbon interface promotes interfacial charge transfer, enhances CO₂ adsorption/activation, improves reaction kinetics, and suppresses excessive hydrogen evolution, while oxygen vacancies create localized electron-rich centers that facilitate *CO hydrogenation toward the key *CHO intermediate. Benefiting from this complementary regulation, G/Vo-Cu₂O balances the formation and stabilization of *CO and *CHO intermediates, thereby favoring the thermodynamically downhill *CO*CHO coupling pathway over conventional *CO*CO or *CHO*CHO dimerization. In situ Fourier-transform infrared spectroscopy further confirms the enhanced generation of *CHO and *COCHO intermediates during CO₂RR. As a result, the optimized G/Vo-Cu₂O catalyst achieves a C₂H₄ Faradaic efficiency of 62.4 ± 4.4% at -1.2 V versus reversible hydrogen electrode, accompanied by suppressed H₂ and CO formation. This work highlights the importance of interface-defect dual electronic regulation in steering CO₂RR selectivity and provides mechanistic insights for designing Cu-based catalysts toward efficient C₂₊ production.