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

Abstract The electrochemical nitrate reduction reaction (NO₃⁻RR) presents an environmentally friendly approach for efficient NO₃⁻ pollutant removal and ammonia (NH₃) production, compared to the conventional Haber–Bosch approach. While core/shell engineering has demonstrated its potential in enhancing NO₃⁻RR performance, significant synthetic challenges and limited shell layer modification capabilities impede the exploration of high‐performance NO₃⁻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 NH₃ Faradaic efficiency (FE) of 94.7% at −0.5 V_RHE with excellent durability and selectivity for NH₃ over a wide range of potentials in NO₃⁻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−NO₃⁻ battery device attains a peak current density exceeding 32 mA cm⁻² and an NH₃ yield of up to 145.4 µmol h⁻¹ cm⁻². The work offers a novel core/shell engineering strategy in electrocatalytic NO₃⁻RR and sheds light on the doping effects on the electrochemical NH₃ synthesis.