Shape- and Composition-Sensitive Activity of Pt and PtAu Catalysts for Formic Acid Electrooxidation

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• 作者：Youngmin Kim ; Hyung Ju Kim ; Yong Seok Kim ; Sung Mook Choi ; Min Ho Seo ; Won Bae Kim
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：August 30, 2012
• 年：2012
• 卷：116
• 期：34
• 页码：18093-18100
• 全文大小：608K
• 年卷期：v.116,no.34(August 30, 2012)
• ISSN：1932-7455

文摘

In this work, we have probed the shape- and composition-dependent activities of Pt and PtAu catalysts for formic acid electrooxidation. Pt-based hollow nanostructures such as Pt hollow nanospheres (Pt HNSs), Pt nanotubes (Pt NTs), and PtAu alloy nanotubes (PtAu NTs) with controlled Pt:Au compositions are successfully prepared via a galvanic replacement process using sacrificial Ag templates. The physicochemical properties of these Pt and PtAu catalysts are confirmed by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The electrochemical activities of these hollow structured catalysts are compared for formic acid oxidation by cyclic voltammetry and chronoamperometry methods. Relative to the commercial Pt black and Pt/C nanoparticle catalysts, the hollow nanostructured Pt materials (Pt HNS, Pt NT) exhibit enhanced catalytic activities due to structural effects. Moreover, the bimetallic PtAu NT series shows improved catalytic activities over the monometallic Pt catalysts due to compositional effects. The present study demonstrates that the catalytic activity and the extent of surface poisoning are strongly dependent on both the structural and compositional variations of the nanostructured electrocatalysts, as shown by a systemically prepared series of nanostructured catalysts for formic acid oxidation.