Incorporating Co-Encapsulated N-Doped Carbon Nanotube with Zn Phthalocyanine: Accelerated Water Dissociation Kinetics for Hydroxylamine Electrosynthesis

Abstract Electrocatalytic nitrite (NO2–) reduction to hydroxylamine (NH2OH) under ambient conditions is regarded as a sustainable way to simultaneously enable pollutant abatement and value-added chemical synthesis; however, the intrinsically sluggish kinetics and competing over-reduction to ammonia necessitate the rational exploration of robust electrocatalytic systems. Herein, we report the anchoring of zinc phthalocyanine (ZnPc) molecules onto bamboo-like nitrogen-doped carbon nanotubes encapsulating metallic cobalt nanoparticles (Co-NCNT) for selectively converting NO2– to NH2OH. The resulting ZnPc/Co-NCNT electrocatalyst achieves a considerable NH2OH yield of 0.25 mmol h–1 mgcat–1 and a high Faradaic efficiency of 64.32% at −0.3 V vs RHE, significantly outperforming its monocomponent counterparts. Mechanistic investigations reveal that the Co-NCNT facilitates charge transfer and lowers the water dissociation barrier, securing efficient active hydrogen (*H) supply to drive the hydrogenation processes. Furthermore, the practical viability of this system is demonstrated by constructing a Zn–NO2– battery, which concurrently generates NH2OH while delivering a peak power density of 7.22 mW cm–2. This study underscores the efficacy of synergistically integrating molecular catalysts with functional carriers for selective NO2– electroreduction to NH2OH.