Electrochemical Nitrate Reduction Reaction to Ammonia at Industrial-Level Current Densities

The electrochemical nitrate reduction reaction (NO₃ ^-RR) represents a promising green synthesis technology, enabling both resource utilization of nitrate (NO₃ ^-) pollutants in wastewater and provision of a sustainable ammonia (NH₃) source for carbon neutrality. The key challenge in advancing NO₃ ^-RR toward practical application lies in developing catalytic systems that maintain excellent activity, high selectivity, and long-term stability at industrial-level current densities (>300 mA cm^-2). Although NO₃ ^-RR has been developed to a certain extent, there has yet to be a comprehensive summary and analysis of the advancements in this field at industrial-level current densities up to now. This review begins with an introduction to the mechanism and theoretical basis of NO₃ ^-RR, systematically summarizes and analyzes catalyst design strategies for industrial-level current densities, including alloying methods, in situ derivation strategy, heterostructure construction, doping engineering, and self-supporting electrode fabrication. In addition, the progress of industrial-level NO₃ ^-RR-based electrolyzers, including flow reactor and membrane electrode assembly (MEA) technology are discussed. Meanwhile, techno-economic analysis (TEA) and life cycle assessment (LCA) are employed to investigate the economic viability and environmental impact of NO₃ ^-RR, providing a comprehensive evaluation of the feasibility for large-scale application. Furthermore, the current challenges of catalytic systems under industrial electrolysis conditions are clarified, and the future development directions toward industrial-scale NH₃ synthesis are proposed, aiming to promote the value-added electrochemical conversion of pollutants and develop the industrial application of NO₃ ^-RR technology.