Fe Nanoparticles Encapsulated in N-doped Porous Carbon for Efficient Oxygen Reduction in Alkaline Media
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 use a facile approach to synthesize Fe nanoparticles encapsulated in N-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 shows excellent ORR activity in alkaline solutions (E0 = 0.97 V vs. RHE, E1/2 = 0.89 V vs. RHE). Moreover, the Fe@N-C-30 catalyst exhibits 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.