Upcycling Nitrate Waste into Power: Designing Mo Incorporated Ni–Fe Based Phosphide Nanosheets for Electrocatalytic Green Ammonia Synthesis and Zn-Nitrate Batteries

The electrocatalytic nitrate reduction reaction (NO₃⁻RR) has emerged as a promising route for simultaneous nitrate removal and ammonia (NH₃) synthesis. However, achieving high NH₃ yield rates and Faradaic efficiencies (FE) under neutral pH conditions remains challenging. In this work, Mo-incorporated FeNiP (MFNP-x; x denotes the Mo%) electrocatalysts are synthesized via a one-step, binder-free electrodeposition method. Incorporation of 10% Mo into the FNP lattice significantly enhances both the NH₃ yield rate and FE by suppressing side-product formation. The optimized MFNP-10 catalyst achieves an exceptional NH₃ yield rate of 16271.27 µg h⁻¹ mg_cat⁻¹ and an FE of 96.45% at −0.6 V (vs RHE) in a neutral electrolyte containing 0.5 m Na₂SO₄ and 0.1 m KNO₃. Computational findings assisted with Machine learning (ML) and Density functional theory (DFT) reveal that Mo incorporation synergistically enhances nitrate adsorption and introduces an alternative reduction pathway with a lower activation energy barrier. Moreover, a Zn–NO₃⁻ battery constructed using MFNP-10 as cathode delivers a peak power density of 9.73 mW cm⁻², excellent stability, and an NH₃ yield of 2236.27 µg h⁻¹ mg_cat⁻¹ with 93.85% FE. This study demonstrates a facile one-step design strategy for developing high-performance catalysts that couple sustainable energy storage with efficient NH₃ production.