Boosting ammonia electrosynthesis via interfacial tandem nitrate reduction enabled by an amorphous@crystalline electrocatalyst

Abstract

Electrocatalytic ammonia synthesis through the nitrate to ammonia (NRA) technique is of energy and environmental sustainability for the nitrogen cycle. Nevertheless, the nitrite (*NO₂) intermediate may desorb, which would reduce the productivity of ammonia and the of Faradaic efficiency. Here, a heterostructured electrocatalyst consisting of amorphous CuO and crystalline CeO₂ is prepared for efficient NH₃ production through the interface tandem [2 + 6]-electron electrocatalysis approach. In alkaline medium, the NH₃ yield and Faradaic efficiency reach 8.6 mg h⁻¹ mg_cat⁻¹ and 96 %, respectively. As evidenced by the in situ experiments and theoretical calculations, the amorphous@crystalline interfacial local unsaturated Cu-Ce bimetallic site configuration endows the heterostructured electrocatalyst with strong *NO₂ adsorption abilities and sufficient *H supply, which synergistically catalyze NH₃ production through the [2 + 6]-electron NRA process. Furthermore, the Zn-NO₃⁻ battery devices, constructed with amorphous-CuO@crystalline-CeO₂ as electrode materials, demonstrate outstanding application results. This work suggests an achievable route for promoting the NRA activity, enabling simultaneous ammonia production, electricity generation, and wastewater treatment, and holds great potential for the development of new heterostructured electrocatalysts for NH₃ production.