Trimetallic CuCoRu catalyst with multiple active sites for industrial-scale nitrate electroreduction to ammonia

The electrochemical nitrate reduction reaction (NO₃⁻RR) represents a promising and environmentally friendly approach for both the removal of nitrate (NO₃⁻) pollutants and the production of high-value ammonia (NH₃). However, this process faces significant challenges in achieving industrial application due to mismatched reaction kinetics involved in the conversion of NO₃⁻ to NO₂⁻, the formation of active hydrogen (H*) via water dissociation, and the stepwise hydrogenation processes. In this study, we developed a trimetallic CuCoRu catalyst with multiple active sites to enhance the selective NH₃ synthesis at industrial-scale current density, where Cu primarily catalyzes the reduction of NO₃⁻ to NO₂⁻, Co facilitates the deep hydrogenation of NO₂⁻ to NH₃, and Ru promotes water dissociation to generate H*, effectively bridging the aforementioned processes. The optimized CuCoRu catalyst achieves near-100% NH₃ Faradaic efficiency with an NH₃ yield rate of 14.6 mmol h⁻¹ cm⁻² at a current density of 2.5 A cm⁻². The practical application in simulated wastewater with different NO₃⁻ concentrations and in the membrane electrode assembly demonstrates great potential for industrial application.