Fe-Induced Coordination Environment Regulation in MOF-Derived Carbon Materials for Oxygen Reduction
Yuandong Yang, Qi Huang, Qiuhong Sun, Jinhang Xue, Shaojie Xu, Lujiao Mao, Xuemei Zhou, Dai Yu, Qipeng Li, Jinjie Qian
Abstract
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.