Electronic reconfiguration induced by dynamic hydroxyl decoration facilitates electrochemical nitrate reduction to ammonia

Abstract

Electrochemical conversion from nitrate to ammonia becomes a feasible technology to improve nitrate pollutants and realize room-temperature ammonia synthesis, but which is limited by multiple competing reaction and low energy conversion efficiency. Herein, we suggest dense and well-defined magnetic metal sites on the M(CN)₃ (M = Fe, Co, Ni) surface with spontaneous hydroxyl decoration, which leads to electronic rearrangement at half-filled 3d orbitals due to its tailored coordination environment that optimizes nitrate adsorption and dissociation. The comprehensive calculations associated with density functional theory disclose that the rate-limiting potential barrier effectively reduces and finally leads to a higher nitrogen conversion ability, because the bonding interaction and electron transfer between metal sites and reactants is optimized by decorating hydroxyls. This work provides a new insight into understanding the reaction kinetics for nitrate reduction.