Facile Fabrication of Ag-Pd Bimetallic Nanoparticles in Ultrathin TiO2-Gel Films: Nanoparticle Morphology and Catalytic Activity

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• 作者：Junhui He ; Izumi Ichinose ; Toyoki Kunitake ; Aiko Nakao ; Yukihide Shiraishi ; and Naoki Toshima
• 刊名：Journal of the American Chemical Society
• 出版年：2003
• 出版时间：September 10, 2003
• 年：2003
• 卷：125
• 期：36
• 页码：11034 - 11040
• 全文大小：276K
• 年卷期：v.125,no.36(September 10, 2003)
• ISSN：1520-5126

文摘

Ag-Pd bimetallic nanoparticles were prepared directly in ultrathin TiO₂-gel films by a stepwiseion-exchange/reduction approach. Ion-exchange sites were created in ultrathin films using Mg²⁺ ions astemplate. Ag⁺ ion was then incorporated by ion exchange, and converted into metallic nanoparticles bylow-temperature H₂ plasma, regenerating ion-exchange sites. The same procedure was then carried outfor Pd²⁺ ion, producing Pd-on-Ag bimetallic nanoparticles, as TEM observation and plasmon resonanceabsorption indicate. By contrast, reversed metal incorporation procedure appeared to give a mixture ofindividual Ag and Pd nanoparticles, as confirmed by TEM, absorption spectroscopy and X-ray photoelectronspectroscopy. For hydrogenation of methyl acrylate, the catalytic activity of the Pd-on-Ag nanoparticle is367 times as large as that of commercial Pd black and 1.6 times as large as that of Pd monometallicnanoparticle. The outstanding catalytic activity was explicable by the large fraction of the surface-exposedPd atoms. The formation process of the bimetallic nanoparticle and their general morphological featureare discussed.