Electrochemical Synthesis of Mesoporous Pt鈥揂u Binary Alloys with Tunable Compositions for Enhancement of Electrochemical Performance

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• 作者：Yusuke Yamauchi ; Akihisa Tonegawa ; Masaki Komatsu ; Hongjing Wang ; Liang Wang ; Yoshihiro Nemoto ; Norihiro Suzuki ; Kazuyuki Kuroda
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：March 21, 2012
• 年：2012
• 卷：134
• 期：11
• 页码：5100-5109
• 全文大小：623K
• 年卷期：v.134,no.11(March 21, 2012)
• ISSN：1520-5126

文摘

Mesoporous Pt鈥揂u 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鈥揂u binary alloys without phase segregation. The framework composition in the mesoporous Pt鈥揂u alloy was controlled simply by changing the compositional ratios in the precursor solution. Mesoporous Pt鈥揂u 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鈥揂u alloys toward methanol oxidation was highly improved relative to that of nonporous Pt and mesoporous Pt films, suggesting that mesoporous Pt鈥揂u alloy films are potentially applicable as electrocatalysts for direct methanol fuel cells. Also, mesoporous Pt鈥揂u alloy electrodes showed a highly sensitive amperometric response for glucose molecules, which will be useful in next-generation enzyme-free glucose sensors.