Structure of PtnNi Nanoparticles Electrocatalysts Investigated by X-ray Absorption Spectroscopy

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• 作者：Hongliang Bao ; Jiong Li ; Luhua Jiang ; Mingfeng Shang ; Shuo Zhang ; Zheng Jiang ; Xiangjun Wei ; Yuying Huang ; Gongquan Sun ; Jian-Qiang Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 10, 2013
• 年：2013
• 卷：117
• 期：40
• 页码：20584-20591
• 全文大小：441K
• 年卷期：v.117,no.40(October 10, 2013)
• ISSN：1932-7455

文摘

Carbon supported Pt鈥揘i nanoparticles (NPs) electrocatalysts with nominal Pt/Ni atomic ratios of 3:1, 2:1, and 1:1, denoted as Pt₃Ni/C, Pt₂Ni/C, and Pt₁Ni/C, respectively, were obtained by a modified polyol process. The structure of Pt_nNi/C (n = 3, 2, 1) electrocatalysts was studied by using an X-ray absorption spectroscopy technique combined with X-ray diffraction and transmission electron microscopy. Significantly, the NPs of Pt₃Ni/C in air are demonstrated to have a quasi core鈥搒hell structure consisting of a core of metallic Pt surrounded by many small NiO_x clusters. In contrast, both Pt₂Ni/C and Pt₁Ni/C are demonstrated to have an alloy structure with partial oxidation on the surface. Under the atmosphere of H₂ at 393 K, the Pt_nNi/C became the expected bimetallic alloy. At last, we discuss the effect of Ni amount on the structure of Pt_nNi/C and estimate their possible catalytic activity for methanol oxidation reaction. Our results further confirmed that the structure of Pt鈥揘i NPs can be influenced by Ni amount and this effect may be enlarged by environment effects.