Breaking Dilution Limits: Electrocatalytic Ammonia Production from Low‐Concentration Nitrate Streams

Abstract

Abstract The conversion of nitrate (NO 3 − ) in water to high‐value‐added ammonia (NH 3 ) using an electrocatalytic NO 3 − reduction reaction (eNO 3 − RR) provides a viable technological pathway to address the imbalance in the global nitrogen cycle. Unfortunately, most of the existing studies have focused on the ideal conditions of high‐concentration NO 3 − , but most of the polluted waters around the world are usually at low‐concentration levels. Consequently, researching eNO 3 − RR under low‐concentration NO 3 − is more practical. Although the study of low‐concentration NO 3 − has gradually gained attention in recent years, a systematic review of the literature in this area has not yet been reported. To fill this research gap, this paper reviews recent advances in the electrocatalytic reduction of low‐concentration NO 3 − to NH 3 . Initially, the nature of NO 3 − as a reactant, the reaction mechanism of eNO 3 − RR, and the factors affecting the efficiency are introduced. Subsequently, the key challenges of electrocatalytic reduction of low‐concentration NO 3 − are analyzed, and various strategies to improve the performance of eNO 3 − RR are summarized on this basis. Additionally, the feasibility of large‐scale ammonia recovery using eNO 3 − RR under low‐concentration NO 3 − is assessed through application scenario exploration, economic analyses, and life cycle assessment. Ultimately, future research directions are outlined to inspire future work.