Interfacial Microenvironment Engineering for Electrocatalytic Nitrate Reduction toward a Sustainable Nitrogen Cycle

ABSTRACT Nitrate contamination threatens aquatic ecosystems and human health. Electrocatalytic nitrate reduction to ammonia (NO 3 RR) offers a sustainable solution by coupling wastewater remediation with resource recovery. Yet, its practical implementation is limited by complex multi‐electron‐proton transfer processes, severe competition from hydrogen evolution, and sluggish mass transport. This study reviews recent advances in enhancing NO 3 RR through interfacial microenvironment engineering. Strategies such as local pH regulation, electric double‐layer optimization, interfacial water network reconstruction, and reactant enrichment are discussed in relation to their roles in controlling reaction pathways, improving selectivity, and boosting energy efficiency. Developments in membrane electrode assemblies and membrane‐free electrochemical systems are highlighted to demonstrate the importance of microenvironmental control in reactor design. Future directions emphasize multi‐scale mechanistic understanding, intelligent catalyst development, and integrated system design to facilitate the transition of NO 3 RR from laboratory research to industrial application. This work provides a conceptual foundation for realizing a sustainable nitrogen cycle and advancing a sustainable ammonia economy.