The development of electrocatalysts capable of efficient reduction of nitrate (NO₃⁻) to ammonia (NH₃) is drawing increasing interest for the sake of low carbon emission and environmental protection. Herein, we present a CuCo bimetallic catalyst able to imitate the bifunctional nature of copper-type nitrite reductase, which could easily remove NO₂⁻via the collaboration of two active centers. Indeed, Co acts as an electron/proton donating center, while Cu facilitates NO_x⁻adsorption/association. The bio-inspired CuCo nanosheet electrocatalyst delivers a 100 ± 1% Faradaic efficiency at an ampere-level current density of 1035 mA cm⁻²at −0.2 Vvs. Reversible Hydrogen Electrode. The NH₃production rate reaches a high activity of 4.8 mmol cm⁻²h⁻¹(960 mmol g_cat⁻¹h⁻¹). A mechanistic study, using electrochemical in situ Fourier transform infrared spectroscopy and shell-isolated nanoparticle enhanced Raman spectroscopy, reveals a strong synergy between Cu and Co, with Co sites promoting the hydrogenation of NO₃⁻to NH₃via adsorbed *H species. The well-modulated coverage of adsorbed *H and *NO₃led simultaneously to high NH₃selectivity and yield.

Ammonia (NH₃) is a highly important industrial chemical used as fuel and fertilizer. The industrial synthesis of NH₃ relies heavily on the Haber–Bosch route, which accounts for roughly 1.2% of global annual CO₂ emissions. As an alternative route, the electrosynthesis of NH₃ from nitrate anion (NO₃⁻) reduction (NO₃⁻RR) has drawn increasing attention, since NO₃⁻RR from wastewater to produce NH₃ can not only recycle waste into treasure but also alleviate the adverse effects of excessive NO₃⁻ contamination in the environment. This review presents contemporary views on the state of the art in electrocatalytic NO₃⁻ reduction over Cu-based nanostructured materials, discusses the merits of electrocatalytic performance, and summarizes current advances in the exploration of this technology using different strategies for nanostructured-material modification. The electrocatalytic mechanism of nitrate reduction is also reviewed here, especially with regard to copper-based catalysts.

Electrocatalytic reduction of nitrate (NO₃⁻) to ammonia (NH₃) is garnering increasing interest due to its potential to reduce CO₂ emissions as a substitute for the Haber-Bosch process, while also mitigating NO₃⁻ pollution.