Tailoring the electronic landscape of MOFs: Mechanistic elucidation and a roadmap for next-generation nitrogen fixation catalysts

Green ammonia (NH 3 ) serves dual critical roles in the production of fertilizers, dyes, explosives, and resins and actes as a carbon-neutral energy vector. Metal-organic frameworks (MOFs) and MOFs-based nanomaterials (composites and derivatives), rising star materials, have been shown the widespread employment as catalysts (electrocatalysts, photocatalysts, and photoelectrochemical catalysts) for the NH 3 synthesis via the nitrogen reduction reaction (NRR) because of their advantages of high specific surface areas and large pores, tunable channels, and the homogeneous distribution of metal active sites. Varieties of MOFs, MOFs-related composites, and MOFs-based derivatives were discussed, including their synthesis, formation mechanism of nanostructures, and the regulation strategies of local electronic structures of active sites containing MOFs-based electrocatalysts. In addition, the characterization techniques related to the regulation methods of electron structures of active sites and existing challenges are highlighted in detail. Further, the extensive applications of MOFs-based NRR catalysts on the NH 3 synthesis via diverse catalysis methods were summarized, following by the discussion of the future research directions and prospects for the development of MOF-based catalysts. ‌This review is expected to substantially advance the development of MOF-based electrocatalysts for sustainable ammonia synthesis through NRR mechanisms.