Metal–Organic Frameworks for Electrocatalytic Nitrate Reduction: Strategies, Mechanisms, and Perspectives

Electrocatalytic nitrate reduction reaction (NO₃RR) has been emerging as a sustainable route for ammonia synthesis under ambient conditions. Metal–organic frameworks (MOFs), possessing well-defined crystal structures and tunable coordination environments, are regarded as an ideal platform for electrocatalytic NO₃RR. In this review, we systematically highlight the recent breakthroughs in MOF-based electrocatalysts for NO₃RR, from the perspectives of structural design strategies, reaction mechanisms, and future outlooks. Ligand engineering, metal node engineering, and heterostructure engineering strategies are discussed here. After that, the structure–activity relationships and the prevailing reaction mechanisms of NO₃RR on MOFs, including the direct eight-electron transfer pathway and tandem mechanism, are analyzed. Moreover, we outline the current challenges and future prospects concerning the application of MOFs in NO₃RR, with the aim of paving the way for the rational design of next-generation MOF-based electrocatalysts.