N-Doped porous tremella-like Fe3C/C electrocatalysts derived from metal-organic frameworks for oxygen reduction reaction

N-Doped porous tremella-like Fe3C/C electrocatalysts derived from metal-organic frameworks (MOFs) were fabricated via a facile approach. The simply designed catalytic materials have unique fluffy multilayer interconnected porous morphology, which provides a large specific surface area and effectively prevents the agglomeration of nanoparticles. These special features create more active sites (Fe-N-x) on the surface of the electrocatalysts for oxygen reduction reaction (ORR) and the presence of the Fe-N-x active sites was verified via X-ray photoelectron spectroscopy. The effect of Fe intake through pyrolysis of MOFs materials was also studied and the composite with 0.04 g Fe source exhibited excellent ORR performance, a very small hydrogen peroxide yield, and followed the four-electron transfer pathway. The ORR activity of the electrocatalyst is comparable to that of commercial Pt/C, while the stability is even better than the latter in an alkaline solution. The facile method of preparing a multilayer porous N-doped tremella-like Fe3C/C electrocatalyst is a promising electrode material for a wide range of applications in fuel cells and metal-air batteries.