Recent advances in mechanistic studies and catalyst development for electrochemical nitrate reduction to ammonia

Increasing nitrate (NO₃^-) concentration in water bodies due to anthropogenic activities has become a leading environmental challenge of the 21st century. Electrochemical nitrate reduction reaction (eNO₃RR) offers a sustainable solution by simultaneously removing nitrates and producing ammonia, a valuable feedstock. However, eNO₃RR possesses significant challenges, such as efficiency, competing reactions, product selectivity, catalyst stability, etc. This review article highlights the importance of eNO₃RR, its mechanistic pathway, in-situ/operando techniques to understand the mechanistic pathway, reactor design, analytical challenges in product estimation, and catalyst designing strategies. This work uniquely integrates in-situ studies, mechanistic insights, and design principles to establish clear structure-activity correlations for advancing eNO₃RR catalysts. We conclude with current challenges and prospects to guide future research toward efficient and selective catalysts for eNO₃RR-driven ammonia production.