In Situ Activated, Distorted, and Defective Cu for Nitrate Reduction Reaction

ABSTRACT Ammonia production via the eco‐friendly electrochemical nitrate reduction is an emerging area. The lattice modification of pure copper, an important catalyst, remains under‐investigated for broad applications. In this study, we present copper nanoparticles with a distorted and defective lattice structure, derived from the electrochemical transformation of multiphase copper molybdate. These defective and distorted nanoparticles exhibit highly efficient nitrate reduction across a wide potential range, achieving >80% Faradaic efficiency from −0.4 to −1.0 V with a peak efficiency of 94.6% at −0.8 V, notably over eight times higher than Cu powder, reaching an ammonia yield of 52.2 mg·h −1 ·mg cat −1 . Theoretical calculations reveal lattice compression, in conjunction with Cu vacancies, shifts the d ‐band center away from the Fermi level. Additionally, the localized electrons modulate intermediate adsorption on the copper surface, facilitating a balance between the adsorption and desorption of intermediates. This research not only systematically explores the evolution of molybdate and its impact on copper lattice transformation but also advances the development of nitrate reduction catalysts.