Abstract
Three-dimensional (3D) N-doped graphene aerogel (N-GA)-supported Fe₃O₄nanoparticles (Fe₃O₄/N-GAs) as efficient cathode catalysts for the oxygen reduction reaction (ORR) are reported. The graphene hybrids exhibit an interconnected macroporous framework of graphene sheets with uniform dispersion of Fe₃O₄nanoparticles (NPs). In studying the effects of the carbon support on the Fe₃O₄NPs for the ORR, we found that Fe₃O₄/N-GAs show a more positive onset potential, higher cathodic density, lower H₂O₂ yield, and higher electron transfer number for the ORR in alkaline media than Fe₃O₄NPs supported on N-doped carbon black or N-doped graphene sheets, highlighting the importance of the 3D macropores and high specific surface area of the GA support for improving the ORR performance. Furthermore, Fe₃O₄/N-GAs show better durability than the commercial Pt/C catalyst.