Yolk-shell Fe@FeNx nanoparticles decorated N-doped mesoporous carbon as highly active electrocatalyst for oxygen reduction reactions

Iron/nitrogen co-doped carbon materials (Fe/N-C) have been extensively investigated as oxygen reduction reaction (ORR) catalysts in alkaline medium. Here, Fe3O4 nanoparticles decorated carbon black is encapsulated with polypyrrole and subsequently utilized as a precursor to synthesize a highly efficient ORR catalyst through pyrolysis. Interestingly, this catalyst consists of yolk-shell Fe@FeNx and N-doped porous carbon, demonstrating a synergistically improved ORR activity. It shows better durability, Pt-comparable activity, and superior tolerance against methanol crossover under alkaline conditions. Control experiments confirm that yolk-shell Fe@FeNx nanoparticles provide efficient catalytic sites and facilitate charge transfer in ORRs. Thus, this study provides a new kind of Fe/N-C electrocatalyst synthesized to be nitride rather than carbide simply with a heat-treatment under N-2 atmosphere. (C) 2020 Elsevier B.V. All rights reserved.