Design, mechanisms, and applications of iron-based metal-organic frameworks derived electrocatalysts for zinc-air batteries

Zinc-air batteries (ZABs) offer high theoretical energy density and safety but face commercialization hurdles due to sluggish oxygen reduction (ORR) and evolution (OER) kinetics at the air cathode, demanding efficient catalysts. This review comprehensively examines iron-based metal-organic frameworks (Fe-MOFs) and their derivatives as promising catalysts for ZABs. It begins by outlining ZAB fundamentals and the critical role of air cathode catalysts. The unique advantages of Fe-MOFs: ultra-high surface area, tunable pores, abundant Fe²⁺/Fe³⁺ active centers, low cost, and eco-friendliness—are highlighted, alongside their catalytic mechanisms. The discussion covers pristine Fe-MOF catalysts, emphasizing unsaturated metal center regulation and bimetallic synergies. A major focus is Fe-MOF-derived catalysts obtained via pyrolysis, including metal compounds (oxides, sulfides, phosphides), single-atom catalysts (SACs), dual-atom catalysts (DACs), alloys (including high-entropy alloys), core-shell structures, and heterostructures. These derivatives enhance conductivity, expose active sites, and optimize electron transfer, significantly boosting ORR/OER performance. Furthermore, composite catalysts integrating Fe-MOFs with metal compounds, carbon materials (CNTs, graphene), other MOFs, and covalent organic frameworks (COFs) are summarized, leveraging synergistic effects to overcome limitations like poor conductivity. Finally, current challenges (e.g., stability, precise site control) and future research directions are outlined, providing insights for developing high-performance, non-precious metal ZAB catalysts.