Nitrogen-doped graphene-wrapped iron nanofragments for high-performance oxygen reduction electrocatalysts

Jang Yeol Lee, Na Young Kim, Dong Yun Shin, Hee Young Park, Sang-Soo Lee, S. Joon Kwon, Dong Hee Lim, Ki Wan Bong, Jeong Gon Son, Jin Young Kim

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Transition metals, such as iron (Fe)- or cobalt (Co)-based nanomaterials, are promising electrocatalysts for oxygen reduction reactions (ORR) in fuel cells due to their high theoretical activity and low cost. However, a major challenge to using these metals in place of precious metal catalysts for ORR is their low efficiency and poor stability, thus new concepts and strategies should be needed to address this issue. Here, we report a hybrid aciniform nanostructures of Fe nanofragments embedded in thin nitrogen (N)-doped graphene (Fe@N-G) layers via a heat treatment of graphene oxide-wrapped iron oxide (Fe2O3) microparticles with melamine. The heat treatment leads to transformation of Fe2O3 microparticles to nanosized zero-valent Fe fragments and formation of core-shell structures of Fe nanofragments and N-doped graphene layers. Thin N-doped graphene layers massively promote electron transfer from the encapsulated metals to the graphene surface, which efficiently optimizes the electronic structure of the graphene surface and thereby triggers ORR activity at the graphene surface. With the synergistic effect arising from the N-doped graphene and Fe nanoparticles with porous aciniform nanostructures, the Fe@N-G hybrid catalyst exhibits high catalytic activity, which was evidenced by high E1/2 of 0.82 V, onset potential of 0.93 V, and limiting current density of 4.8 mA cm−2 indicating 4-electron ORR, and even exceeds the catalytic stability of the commercial Pt catalyst.

Original languageEnglish
Article number98
JournalJournal of Nanoparticle Research
Volume19
Issue number3
DOIs
Publication statusPublished - 2017 Mar 1

Keywords

  • Catalyst nanomaterial
  • Doping
  • Graphene
  • Non-precious metal electrocatalyst
  • Oxygen reduction reaction

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Atomic and Molecular Physics, and Optics
  • Modelling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics

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  • Cite this

    Lee, J. Y., Kim, N. Y., Shin, D. Y., Park, H. Y., Lee, S-S., Joon Kwon, S., Lim, D. H., Bong, K. W., Son, J. G., & Kim, J. Y. (2017). Nitrogen-doped graphene-wrapped iron nanofragments for high-performance oxygen reduction electrocatalysts. Journal of Nanoparticle Research, 19(3), [98]. https://doi.org/10.1007/s11051-017-3793-y