Metal–Support Interactions at Cu Single–Atom/Oxygen–Vacancy Interfaces Boost Urea Electrosynthesis

Electrocatalytic co–reduction of CO 2 and NO 3 − provides a sustainable alternative to conventional energy–intensive urea synthesis but remains limited by complex proton–coupled electron transfer processes and sluggish C–N coupling kinetics. Herein, a Cu single–atom catalyst anchored on oxygen–vacancy–rich, urchin–like Fe 2 O 3 (Cu SA @Fe 2 O 3 ) is developed for efficient urea electrosynthesis. Benefiting from oxygen–vacancy–induced interfacial charge redistribution and a strong electronic metal–support interaction (EMSI), the catalyst effectively lowers the kinetic barrier for C–N coupling while suppressing competing reactions. The optimized Cu SA @Fe 2 O 3 (2.16%) achieves a high urea yield rate of 4941.24 μg h −1 mg cat −1 and a Faradaic efficiency of 68.6% at −0.37 V vs. the reversible hydrogen electrode (RHE). In situ Fourier transform infrared spectroscopy and density functional theory (DFT) calculations further reveal that the Cu/Fe 2 O 3 interface facilitates C–N coupling between *NH 2 and *CO, significantly lowering the thermodynamic barriers for key intermediates activation and subsequent C–N bond formation. This work highlights the pivotal role of single–atom/vacancy interfacial engineering in promoting complex multi–electron electrosynthesis reactions.