合理设计和合成非贵金属催化剂对提高氧还原反应的催化活性和稳定性具有重要意义，但仍然存在重大挑战。本工作采用功能化金属有机框架材料为前驱体，合成了氮掺杂多孔碳包覆Fe纳米粒子催化剂（Fe@N-C）。Fe纳米颗粒的嵌入提高了催化剂的石墨化程度和石墨化氮的比例，同时促进了中孔的形成。Fe@N-C-30催化剂在碱性溶液中表现出良好的氧还原反应活性（E₀ = 0.97 V vs. RHE，E_1/2 = 0.89 V vs. RHE）。此外，与商用Pt/C相比，Fe@N-C-30催化剂具有更好的耐甲醇性和循环稳定性。其优异的电催化活性归因于高的电化学表面积、相对高比例的石墨化氮、独特的孔结构以及包覆的Fe颗粒与碳层之间的协同效应。本工作为利用金属有机框架材料制备高效非贵金属ORR催化剂提供了一种有前景的方法。

Rational design and synthesis of non-precious-metal catalyst plays an important role in improving the activity and stability for oxygen reduction reaction (ORR) but remains a major challenge. In this work, we used a facile approach to synthesize iron nanoparticles encapsulated in nitrogen-doped porous carbon materials (Fe@N-C) from functionalized metal-organic frameworks (MOFs, MET-6). Embedding Fe nanoparticles into the carbon skeleton increases the graphitization degree and the proportion of graphitic N as well as promotes the formation of mesopores in the catalyst. The Fe@N-C-30 catalyst showed the excellent ORR activity in alkaline solutions (E₀ = 0.97 V vs. RHE, E_1/2 = 0.89 V vs. RHE). Moreover, the Fe@N-C-30 catalyst exhibited better methanol resistance and long-term stability when compared to commercial Pt/C. The superior ORR performance could be attributed to the combination of high electrochemical surface area, relative high portion of graphitic-N, unique porous structures and the synergistic effect between the encapsulated Fe particles and the N-doped carbon layer. This work provides a promising method to construct efficient non-precious-metal ORR catalyst through MOFs.