Coembedding Fe Single\nAtom–Coupled MoC Nanoparticles\nin N‑Doped Hierarchically Porous Carbon Cubes for Oxygen Electroreduction

Promotion of oxygen reduction reaction (ORR) kinetics,\nto a large\nextent, depends on the rational modulation of the electronic structure\nand mass diffusion of electrocatalysts. Herein, a ferrocene (Fc)–assisted\nstrategy is developed to prepare Fc-trapped ZnMo–hybrid zeolitic\nimidazolate framework (Fc@ZnMo-HZIF-50) and the derived Fe single\natom coupling with MoC nanoparticles, coembedded in hierarchically\nporous N-doped carbon cubes (MoC@FeNC-50). The introduced Fc is utilized\nnot only as an iron source for single atoms but also as a morphology\nregulator for generating a hierarchically porous structure. The redistribution\nof electrons between Fe single atoms and MoC nanoparticles effectively\npromotes the adsorption of O<sub>2</sub> and the formation of *OOH\nintermediates during the ORR process. Along with a 3D hierarchically\nporous architecture for enhanced mass transport, the as-fabricated\nMoC@FeNC-50 presents excellent activity (<i>E</i><sub>1/2</sub> = 0.83 V) and durability (only 9.5% decay in current after 40000\ns). This work could inspire valuable insights into the construction\nof efficient electrocatalysts through electron configuration and kinetics\nengineering.