Excavated Fe-N-C Sites for Enhanced Electrocatalytic Activity in the Oxygen Reduction Reaction

Authors

  • Beomgyun Jeong,

    1. School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
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  • Dongyoon Shin,

    1. School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
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  • Dr. Hongrae Jeon,

    1. School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
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  • Joey D. Ocon,

    1. School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
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  • Prof. Bongjin Simon Mun,

    1. Ertl Center for Electrochemistry and Catalysis, RISE, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
    2. Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
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  • Dr. Jaeyoon Baik,

    1. Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (South Korea)
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  • Dr. Hyun-Joon Shin,

    1. Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (South Korea)
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  • Prof. Dr. Jaeyoung Lee

    Corresponding author
    1. School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
    2. Ertl Center for Electrochemistry and Catalysis, RISE, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)
    • School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea)

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Abstract

Platinum (Pt) is the best electrocatalyst for the oxygen reduction reaction (ORR) in hydrogen fuel cells, but it is an extremely expensive resource. The successful development of a cost-effective non-Pt ORR electrocatalyst will be a breakthrough for the commercialization of hydrogen-air fuel cells. Ball milling has been used to incorporate metal and nitrogen precursors into micropores of carbon more effectively and in the direct nitrogen-doping of carbon under highly pressurized nitrogen gas in the process of the preparation of non-noble ORR catalysts. In this study, we first utilize ball milling to excavate the ORR active sites embedded in Fe-modified N-doped carbon nanofibers (Fe-N-CNFs) by pulverization. The facile ball-milling process resulted in a significant enhancement in the ORR activity and the selectivity of the Fe-N-CNFs owing to the higher exposure of the metal-based catalytically active sites. The degree of excavation of the Fe-based active sites in the Fe-N-CNFs for the ORR was investigated with cyclic voltammetry, X-ray photoelectron spectroscopy, and pore-size distribution analysis. We believe that this simple approach is useful to improve alternative ORR electrocatalysts up to the level necessary for practical applications.

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