Rational Design of Cu‐Based Catalysts for Nitrate to Ammonia Electroreduction: A Structure–Limitation–Strategy Perspective

Cu‐based catalysts have emerged as promising candidates for electrocatalytic nitrate reduction reaction (eNO 3 RR), offering an energy‐efficient alternative to the Haber–Bosch process while enabling the remediation of nitrate‐containing wastewater. However, eNO 3 RR on Cu remains limited by coupled thermodynamic and kinetic challenges, including scaling‐constrained intermediate adsorption, insufficient control over hydrogen supply and selectivity, and increasingly severe interfacial bottlenecks under high‐current‐density operation. Rational catalyst design is therefore required to address distinct but coupled limitations, including nitrate activation, intermediate hydrogenation, hydrogen availability, HER competition, and interfacial mass/charge transport. In this work, we summarize the mechanistic basis of Cu‐based eNO 3 RR and discuss how multiscale structural strategies alleviate these recurring bottlenecks. Moreover, this review summarizes recent works from a structure–limitation–strategy perspective, spanning atomic‐scale coordination engineering; site cooperativity; nanostructure, defect, and phase‐boundary engineering; and interfacial microenvironment regulation . Finally, we outline future directions for Cu‐based catalysts, with an emphasis on realistic water matrices, high‐current stability, ammonia recovery, AI‐assisted catalyst optimization, and product‐oriented selectivity.