Defect-induced triple synergistic modulation in copper for superior electrochemical ammonia production across broad nitrate concentrations

Electrochemical nitrate reduction reaction (NOxRR) to produce ammonia while treating sewage is a grand challenge. This paper reports a defect-rich Cu nanowire array electrode (V-Cu NAE), created via in-situ electrochemical reduction, demonstrating superior NOxRR performance across a wide nitrate concentration range (1-100 mM). The V-Cu NAE achieves current densities from 50 to 1100 mA cm⁻² with >90% Faradaic efficiency. Operando Synchrotron radiation Fourier Transform Infrared Spectroscopy and DFT calculations reveal a triple synergistic modulation: enhanced nitrate adsorption, promoted water dissociation, and suppressed hydrogen evolution. A two-electrode system integrating NOxRR with glycerol oxidation reaction in industrial wastewater achieves 550 mA cm⁻² at -1.4 V, with 99.9% ammonia selectivity and 99.9% nitrate conversion over 100 h.

Bocheng Zhang, Zechuan Dai, Yanxu Chen, Mingyu Cheng, Huaikun Zhang, Pingyi Feng, Buqi Ke, Yangyang Zhang, Genqiang Zhang