Electrochemical synthesis of mesoporous Pt-Au binary alloys with tunable compositions for enhancement of electrochemical performance

Yusuke Yamauchi, Akihisa Tonegawa, Masaki Komatsu, Hongjing Wang, Liang Wang, Yoshihiro Nemoto, Norihiro Suzuki, Kazuyuki Kuroda

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    Abstract

    Mesoporous Pt-Au binary alloys were electrochemically synthesized from lyotropic liquid crystals (LLCs) containing corresponding metal species. Two-dimensional exagonally ordered LLC templates were prepared on conductive substrates from diluted surfactant solutions including water, a nonionic surfactant, ethanol, and metal species by drop-coating. Electrochemical synthesis using such LLC templates enabled the preparation of ordered mesoporous Pt-Au binary alloys without phase segregation. The framework composition in the mesoporous Pt-Au alloy was controlled simply by changing the compositional ratios in the precursor solution. Mesoporous Pt-Au alloys with low Au content exhibited well-ordered 2D hexagonal mesostructures, reflecting those of the original templates. With increasing Au content, however, the mesostructural order gradually decreased, thereby reducing the electrochemically active surface area. Wide-angle X-ray diffraction profiles, X-ray photoelectron spectra, and elemental mapping showed that both Pt and Au were atomically distributed in the frameworks. The electrochemical stability of mesoporous Pt-Au alloys toward methanol oxidation was highly improved relative to that of nonporous Pt and mesoporous Pt films, suggesting that mesoporous Pt-Au alloy films are potentially applicable as electrocatalysts for direct methanol fuel cells. Also, mesoporous Pt-Au alloy electrodes showed a highly sensitive amperometric response for glucose molecules, which will be useful in next-generation enzyme-free glucose sensors.

    Original languageEnglish
    Pages (from-to)5100-5109
    Number of pages10
    JournalJournal of the American Chemical Society
    Volume134
    Issue number11
    DOIs
    Publication statusPublished - 2012 Mar 21

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    ASJC Scopus subject areas

    • Chemistry(all)
    • Catalysis
    • Biochemistry
    • Colloid and Surface Chemistry

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