Strong electronic interaction in Cu2O/Al2O3 interface for stable electroreduction of CO2 to multi-carbon with ampere-level current density

Achieving industrial ampere-level CO₂RR is hindered due to the instability of Cu⁺ species, the difficulty in CO₂ activation, and the sluggish *CO dimerization. Herein, the strong electronic interaction in Cu₂O nanocavities induced by Cu₂O/Al₂O₃ interface is reported to promote multi-carbon (C₂₊) formation at ampere-level current density. The Cu₂O/Al₂O₃ interfacial dipoles promote the electrons transfer from Cu₂O to reactants, thereby accelerating the reaction kinetics and stabilizing the Cu₂O nanocavities. The lower charge density on the Al₂O₃ surface facilitate CO₂ activation, and the electron backdonation via Al 2p-2π* bond weaken the C-O in *CO, promoting *CO dimerization. Meanwhile, such Al₂O₃ layers can modulate the local microenvironment to further activate CO₂ and promote *CO dimerization. Hence, the catalyst exhibits C₂₊ Faradaic efficiency of 84.7 % at 1200 mA cm⁻². The formation rate and the energy conversion efficiency of C₂₊ reaches 3.7 mmol h⁻¹ cm⁻² and 34.0 % at 1600 mA cm⁻², respectively. Moreover, the catalyst demonstrates an industrial-current (30 A) electrolysis capability with remarkable stability in a 100 cm² membrane electrode assembly (MEA) electrolyzer.