Accelerating Nitrate Electroreduction to Ammonia via Metal–Support Interactions in Ni-WS 2 Catalysts

Electrocatalytic nitrate reduction reaction (NO 3 – RR) is a promising route for both treating NO 3 – -containing wastewater and enabling sustainable ammonia (NH 3 ) synthesis. While two-dimensional (2D) transition metal dichalcogenides (TMDs) catalysts have been widely investigated as catalysts in various electrocatalytic reactions, their practical application in NO 3 – RR remains hindered by inherently sluggish kinetics and insufficient stability. Metal–support interaction (MSI), which enhances charge transfer and stabilizes catalytic sites, offers a compelling strategy to address these challenges. Herein, we design an MSI-driven Ni-WS 2 catalyst via a two-step strategy. The Ni-WS 2 catalyst demonstrates outstanding NO 3 – RR performance, achieving a Faradaic efficiency of 91.7% at −0.3 V RHE with an NH 3 yield rate of 23.3 mg h –1 cm –2 at −0.7 V RHE . Significantly, the Ni-WS 2 catalyst maintained an exceptional stability in a membrane electrode assembly (MEA), sustaining ≈32 mg h –1 cm –2 NH 3 production over 100 h, surpassing most previously reported TMD-based catalysts. Density functional theory (DFT) calculations reveal that MSI between Ni metal and WS 2 support induces interfacial charge redistribution, optimizes adsorption energy of key intermediates and lowers the energy barrier for the rate-determining step (*NH 2 → *NH 3 ). Furthermore, the Zn-NO 3 – battery assembled with Ni-WS 2 cathode exhibits remarkable performance. This work advances a two-step synthesis strategy for high-performance NO 3 – RR electrocatalysts through targeted MSI modulation.