Interfacial Electronic Reconstruction in SnS2/CoS Heterostructure for Efficient Electrochemical Nitrate-to-Ammonia Conversion and Energy–Environment Integration

Electrocatalytic nitrate reduction reaction (NO3RR) provides a promising route for sustainable ammonia synthesis but is often limited by sluggish reaction kinetics, inefficient charge transfer, and competing hydrogen evolution. Herein, a SnS2/CoS heterostructure with strong interfacial electronic coupling is rationally constructed to integrate the complementary catalytic functions of Sn and Co active sites. Benefiting from interfacial electronic reconstruction, the optimized catalyst achieves a Faradaic efficiency of 98.31% and an NH3 yield rate of 9.6 mg h-1 cm-2 at -0.5 V, significantly outperforming the individual components. Combined in situ Raman spectroscopy, electrochemical characterization, and density functional theory calculations reveal that interfacial charge redistribution optimizes nitrate adsorption, facilitates interfacial charge transfer, and accelerates the conversion of nitrate-derived intermediates, thereby enhancing the overall NO3RR kinetics. Furthermore, the assembled Zn-NO3- battery delivers an open-circuit voltage of 1.7 V and a maximum power density of 18 mW cm-2, demonstrating the feasibility of coupling ammonia synthesis with electricity generation. This work highlights interfacial electronic reconstruction as an effective strategy for designing high-performance heterostructured electrocatalysts for sustainable NO3RR.