Hybrid of Iron Nitride and Nitrogen-Doped Graphene Aerogel as Synergistic Catalyst for Oxygen Reduction Reaction

It is extremely desirable but challenging to create highly active, stable, and low-cost catalysts towards oxygen reduction reaction to replace Pt-based catalysts in order to perform the commercialization of fuel cells. Here, a novel iron nitride/nitrogen doped-graphene aerogel hybrid, synthesized by a facile two-step hydrothermal process, in which iron phthalocyanine is uniformly dispersed and anchored on graphene surface with the assist of - stacking and oxygen-containing functional groups, is reported. As a result, there exist strong interactions between Fe x N nanoparticles and graphene substrates, leading to a synergistic effect towards oxygen reduction reaction. It is worth noting that the onset potential and current density of the hybrid are significantly better and the charge transfer resistance is much lower than that of pure nitrogen-doped graphene aerogel, free Fe x N and their physical mixtures. The hybrid also exhibits comparable catalytic activity as commercial Pt/C at the same catalyst loading, while its stability and resistance to methanol crossover are superior. Interestingly, it is found that, apart from the active nature of the hybrid, the large surface area and porosity are responsible for its excellent onset potential and the high density of Fe-N-C sties and small size of Fe x N particles boost charge transfer rate.