Regioselective Doping into Atomically Aligned Core–Shell Structures for Electrocatalytic Reduction of Nitrate to Ammonia

Abstract The electrochemical nitrate reduction reaction (NO 3 − RR) presents an environmentally friendly approach for efficient NO 3 − pollutant removal and ammonia (NH 3 ) production, compared to the conventional Haber–Bosch approach. While core/shell engineering has demonstrated its potential in enhancing NO 3 − RR performance, significant synthetic challenges and limited shell layer modification capabilities impede the exploration of high‐performance NO 3 − RR core/shell catalysts. Herein, CuCoO/Co(OH) 2 core/shell structure via in situ electrochemical activation is synthesized. The catalyst delivers a maximum NH 3 Faradaic efficiency (FE) of 94.7% at −0.5 V RHE with excellent durability and selectivity for NH 3 over a wide range of potentials in NO 3 − RR, surpassing the electrocatalytic performance of both undoped shell and core components. The outstanding performance Cu─CoO/Co(OH) 2 is ascribed to the enhanced charge transfer, stabilization of key reaction intermediates, and regulation of hydrogen adsorption over Cu‐doped core/shell structure. Furthermore, the assembled Zn−NO 3 − battery device attains a peak current density exceeding 32 mA cm −2 and an NH 3 yield of up to 145.4 µmol h −1 cm −2 . The work offers a novel core/shell engineering strategy in electrocatalytic NO 3 − RR and sheds light on the doping effects on the electrochemical NH 3 synthesis.