Self‐Adaptive Co‐W Heteroatomic Interfaces for Efficient and Stable Nitrate‐To‐Ammonia Conversion

ABSTRACT To break the selectivity‐activity trade‐off in nitrate reduction, we report a self‐adaptive W single‐atom‐anchored CoOOH matrix that constructs Co‐W heteroatomic interfaces (referred to as W‐CoOOH) created via a spontaneous etching‐reconstruction process. Operando analysis demonstrates that a reversible electron relay between the Co‐W heteroatomic interfaces, which stabilizes the Co‐W dual active sites during nitrate reduction reaction (NITRR). This adaptive electronic structure enables exceptional performance, including a Faradaic efficiency (FE) over 90% in a wide potential range (0 to −0.8 V vs. reversible hydrogen electrode (RHE) and a high NH ₃ yield rate of 0.64 g h ⁻¹ at 10 A using a 5 × 5 cm ² membrane electrode assembly (MEA). Mechanistic investigations, combining in situ spectroscopy and theoretical calculations, support a local Co‐W interfacial bifunctional pathway in which Co sites preferentially adsorb/activate NO ₃ ⁻ ‐derived intermediates, while W‐associated interfacial sites facilitate H ₂ O dissociation and increase the local availability of hydrogen species for subsequent hydrogenation steps. This dual‐site cooperation is further accompanied by interfacial electronic modulation, which together contributes to the superior NITRR performance of W‐CoOOH.