Recent advances in mechanistic studies and catalyst development for electrochemical nitrate reduction to ammonia
Debasish Halder, Sujan Sen, Sounak Roy
Abstract
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. The electrochemical nitrate reduction reaction (eNO3RR) offers a sustainable solution for addressing nitrate pollution in water by converting it into a valuable feedstock, ammonia, but there are significant challenges in terms of efficiency, competing reactions, product selectivity and catalyst stability. In this Review, the authors highlight in-situ and operando techniques to understand the underlying reaction mechanisms, analytical challenges in product estimation, as well as reactor and catalyst design strategies for advancing eNO3RR-driven ammonia production.