Unraveling structure activity relationships inatomically precise metal nanoclusters for nitrate-to-ammonia electroreduction

The rising anthropogenic discharge of nitrate (NO 3 − ) into air and water presents a critical environmental challenge, driving the urgent need for sustainable remediation solutions. Electrochemical nitrate reduction to ammonia (eNO 3 RA) emerges as a viable and forward-looking strategy simultaneously addressing NO 3 − pollution and enabling the production of NH 3 , a valuable chemical feedstock. This review critically examines recent improvements in eNO 3 RA, with a focus on atomically precise metal nanoclusters (APMNCs) as next-generation electrocatalysts. We discuss the unique properties of APMNCs, including their well-defined atomic structures, tunable active sites, and hierarchical architectures, which together provide powerful platforms for unraveling structure–activity relationships. Special emphasis is placed on strategies such as size control, heterometal doping, ligand engineering, and support integration, exploring their influence on catalytic activity, selectivity, stability, and key performance metrics like faradaic efficiency, NH 3 yield, and NO 3 − conversion rates. By integrating recent mechanistic insights with practical design principles and current advances, this review delineates a holistic framework and implementable strategy for the rational engineering of high-performance, selective and robust APMNC-based electrocatalysts toward sustainable eNO 3 RA. Unresolved challenges and future research directions are highlighted to inspire further breakthroughs in the field.