Electrochemical Reduction of Low‐Concentration Nitrate to Ammonia: Progress, Challenges, and Perspectives

ABSTRACT Electrochemical nitrate reduction to ammonia (ENRA) is a promising strategy for simultaneously achieving nitrogen resource recovery, ammonia production, and nitrate remediation. However, most existing studies focus on high‐concentration nitrate systems associated with specific industrial wastewaters, limiting their applicability to more widespread nitrate‐containing waters. In contrast, nitrate streams derived from groundwater, agricultural runoff, plasma‐assisted nitrogen fixation, and electrochemical nitrogen oxidation reaction are typically present at much lower concentrations, where severe mass‐transfer limitations and intensified hydrogen evolution reaction substantially hinder ammonia production. This review systematically summarizes recent advances in catalyst design, electrochemical engineering, and operational strategies for low‐concentration ENRA, focusing on the regulation of interfacial substrate behavior, active‐species utilization, charge‐transfer processes, and reactor‐level optimization through reactor architecture, flow mode, electrode design, and operating modes. Furthermore, emerging utilization pathways for dilute ammonia products, techno‐economic assessments, practical performance metrics, and integrated ENRA‐based nitrogen conversion frameworks are discussed, together with the potential roles of artificial intelligence and intelligent process control in catalyst discovery, reactor optimization, and sustainable nitrogen recycling.