Fe-Induced Coordination Environment Regulation in MOF-Derived Carbon Materials for Oxygen Reduction

To realize sustainable and environmentally friendly energy requirements, it is of great significance to design and prepare non-noble-metal catalysts with high catalytic activity, selectivity, and stability. In this work, a single-crystal-to-single-crystal structural transformation from cube-shaped MOF-5-NH2 (MOF = metal–organic framework) to sheet-like Zn-BDC-NH2 has been observed by electrostatic attraction and induced coordination between iron ions and amino groups. By pyrolysis of the Fe-doped precursor, the well-preserved and porous MOF-derived carbon (Fe-NPC) with a large specific surface area, a high electrical conductivity, and abundant Fe-based active species (atomic Fe–Nx sites and Fe/Fe3C nanoparticles) can be conveniently obtained. On account of the abovementioned advantages, it shows a positive onset potential (0.972 V), a large limiting diffusion current density (5.412 mA cm–2), a small Tafel slope (40.85 mV dec–1), and robust stability with high current retention (96.03% after 10 h). In this case, the Fe-doped carbon exhibits an efficient oxygen reduction activity close to state-of-the-art Pt/C. Furthermore, through experimental and theoretical studies, the optimized Fe-NPC exhibits excellent performance in terms of the assembled Zn–air battery. Therefore, this work will provide a favorable strategy for the reasonable design and facile preparation of high-performance non-noble-metal electrocatalysts for practical energy-related applications.