Interfacial charge modulation in CuNi alloy core/B,N-doped graphene shell enabling 100 % ammonia-to-nitrite selectivity

Ammonia oxidation reaction (AOR) in aqueous solutions offers an energy-efficient and non-emission route for the simultaneous production of high-value-added nitrite and hydrogen under ambient conditions. However, the presence of ammonia and various nitrogen-containing intermediates in the electrolyte during AOR impose significant challenges, regarding the rapid poisoning for the noble-metal catalysts but severe leaching of the non-noble ones, leading to rapid catalyst deactivation for both. Addressing this issue, we present an encapsulation strategy for CuNi nanoparticles using ultrathin B/N co-doped graphene (CuNi@BNC). This design not only effectively prevents the leaching of the active CuNi nanoparticles but also benefits from an reverse optimization of the graphene surface induced by the underlying CuNi core. As a result, the CuNi@BNC achieves an exceptional nitrite yield rate of 0.49 mol g 1 h –1 while maintaining 100 % NH 3 -to-nitrite selectivity across a wide potential range. Remarkably, this catalyst demonstrates outstanding stability over long-term operation. This work thus tackles the critical limitations of non-noble-metal AOR electrocatalysts, providing a promising solution for the development of cost-effective and robust electrocatalysts for sustainable nitride synthesis via ambient AOR electrocatalysis. • Encapsulation strategy enables durable non-noble catalysts for ammonia electrooxidation. • B/N co-doped graphene shell tunes interfacial charge for selective nitrite electrosynthesis. • Suppresses CuNi leaching, ensuring long-term stability under harsh AOR conditions. • Achieves 0.49 mol g 1 h –1 nitrite yield with 100 % NH 3 -to-nitrite selectivity. • Demonstrates feasibility in coupled AOR–HER and PV–EC integrated systems.