Fe‐Co‐Ni Ternary Single‐Atom Catalysts for Efficient Electrochemical Nitrate Reduction

ABSTRACT Electrochemical nitrate reduction offers a sustainable route to water remediation and ammonia synthesis, yet its activity and selectivity are fundamentally limited by scaling relationships of single‐metal active sites. Here, we report a non‐equilibrium strategy that enables the construction of atomically dispersed FeCoNi trimetallic single‐atom catalyst. In‐situ experiments and theoretical calculations reveal that synergistic metal centers stabilize nitric oxide and promote its hydrogenation with a reduced activation barrier. The catalyst achieves an excellent Faradaic efficiency of 99.4% and a yield rate of 650 µmol h −1 cm −2 in 1 M KOH with 100 mM nitrate, placing it among the top‐performing multi‐metal single‐atom catalysts. Integration into a zinc‐nitrate battery enables simultaneous nitrate removal, sustained electricity generation, and continuous ammonia production. This work provides a general strategy for constructing multi‐metal active sites for nitrate valorization and ammonia synthesis.