Recent Progress of Electrochemical Nitrate Reduction to Ammonia on Copper‐Based Catalysts: From Nanoparticles to Single Atoms

Ammonia (NH 3 ) is a vital chemical for modern human society. It is conventionally produced by the energy‐ and emission‐intensive Haber–Bosch process. Alternatively, sustainable NH 3 production from renewable electricity‐driven electrolyzers has emerged as a promising route. Particularly, NH 3 synthesis from nitrate (NO 3 − ), a common pollutant in water and soil, by the nitrate reduction reaction (NO 3 RR) has drawn wide attention. Among various catalysts demonstrated recently, copper (Cu)‐based catalysts have been recognized as attractive candidates due to their availability, good activity, high NH 3 selectivity, and facile reaction kinetics. In this review, the recent progress of Cu‐based NO 3 RR catalysts from the reaction mechanistic fundamentals to various catalyst design strategies, aiming at providing an on‐time summary, is summarized, and perspectives that can guide the rational and on‐demand design of Cu‐ and other earth‐abundant metal‐based catalysts for selective NO 3 RR toward sustainable NH 3 production are elucidated.