Dynamically Restructuring Nanoporous Cu–Co Electrocatalyst for Efficient Nitrate Electroreduction to Ammonia

The electrochemical nitrate (NO3–) reduction reaction (NITRR) to ammonia (NH3) offers an environmentally friendly alternative for NH3 synthesis but suffers from limited NH3 yield and low Faradaic efficiency (FE) due to the sluggish kinetics of the hydrogenation process. Herein, nanoporous Cu/CoOOH heterostructure is reported as an efficient electrocatalyst for NITRR. The catalyst achieves a high NH3 yield rate of 275.9 μmol h–1 cm–2 (689.8 mmol h–1 gcat–1) and 836.8 μmol h–1 cm–2 (2092.0 mmol h–1 gcat–1), with corresponding FE values of 85.3 and 91.5% in 200 and 1400 ppm of NO3–-N electrolyte, respectively. In situ Raman spectra reveal that the Cu/CoOOH heterostructure is derived from synergistic chemical/electrochemical redox reaction between NO3– and the CuCo alloy during the NITRR process. Theoretical simulations indicate that Cu/CoOOH exhibits enhanced *NO2 affinity and reduces the energy barrier in the rate-determining *NO2H formation step, effectively facilitating NO3– reduction to NH3.