Novel Platinum–Cobalt Alloy Nanoparticles Dispersed on Nitrogen-Doped Graphene as a Cathode Electrocatalyst for PEMFC Applications

Authors

  • Bhaghavathi P. Vinayan,

    1. Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, IITM, Chennai 600036, India
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  • Rupali Nagar,

    1. Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, IITM, Chennai 600036, India
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  • Natarajan Rajalakshmi,

    1. Centre for Fuel Cell Technology, International Advanced Research Centre for Powder Metallurgy and New Materials, ARCI, IIT Madras Research Park, Taramani, Chennai 600 113, India
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  • Sundara Ramaprabhu

    Corresponding author
    1. Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, IITM, Chennai 600036, India
    • Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, IITM, Chennai 600036, India.
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Abstract

A novel synthesis procedure is devised to obtain nitrogen-doping in hydrogen-exfoliated graphene (HEG) sheets. An anionic polyelectrolyte–conducting polymer duo is used to form a uniform coating of the polymer over graphene sheets. Pyrolysis of graphene coated with polypyrrole, a nitrogen-containing polymer, in an inert environment leads to the incorporation of nitrogen atoms in the graphene network with simultaneous removal of the polymer. These nitrogen-doped graphene (N-HEG) sheets are used as catalyst support for dispersing platinum and platinum–cobalt alloy nanoparticles synthesized by the modified-polyol reduction method, yielding a uniform dispersion of the catalyst nanoparticles. Compared to commercial Pt/C electrocatalyst, Pt–Co/N-HEG cathode electrocatalyst exhibits four times higher power density in proton exchange membrane fuel cells, which is attributed to the excellent dispersion of Pt–Co alloy nanoparticles on the N-HEG support, the alloying effect of Pt–Co, and the high electrocatalytic activity of the N-HEG support. A stability study shows that Pt/N-HEG and Pt–Co/N-HEG cathode electrocatalysts are highly stable in acidic media. The study shows two promising electrocatalysts for proton exchange membrane fuel cells, which on the basis of performance and stability present the possibility of replacing contemporary electrocatalysts.

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