Tailoring Electronic and Morphology Features of Iron‐Doped Ni₂P Nanoflowers for Enhanced Ammonia Electrosynthesis in Solid Electrolyte Reactors

Abstract Electrochemical nitrate (NO 3 − ) reduction to ammonia (NH 3 ) presents a promising route for both wastewater treatment and ammonia generation but still suffers from sluggish catalytic activity, insufficient mass transfer, and the reliance on high‐concentration supporting electrolytes. This work reports an innovative and efficient ammonia electrosynthesis reactor by integrating a self‐assembled iron‐doped Ni 2 P (Fe‐Ni 2 P/NF) nanoflower cathode with a solid‐electrolyte (SE). The SE design eliminates the need for supporting electrolytes, providing a highly efficient ion‐conducting pathway and enabling the direct production of NH 3 from NO 3 − . Through tailoring the electronic and surface characteristics of Fe‐Ni 2 P/NF, this reactor achieves complete NO 3 − reduction, 96.7% NH 3 selectivity, and 81.8% faradaic efficiency with a NO 3 − concentration of 100 m m at a current density of 100 mA m −2 . Density functional theory (DFT) calculations reveal that phosphating and Fe doping synergistically enhance NO 3 − adsorption and increase the availability of active hydrogen, thus favoring NH 3 production at a low energy barrier of 0.695 eV. Additionally, the superhydrophilicity of the Fe‐Ni 2 P/NF nanoflower catalyst promotes mass transfer by facilitating electrolyte access and ensuring rapid gas bubble release. This study provides a sustainable and scalable method for converting NO 3 − ‐laden wastewater into valuable ammonia products.