物理化学学报 >> 2001, Vol. 17 >> Issue (02): 134-139.doi: 10.3866/PKU.WHXB20010209

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铂基Pb-Sb表面合金电催化剂的制备与结构表征

夏盛清;陈声培;孙世刚   

  1. 固体表面物理化学国家重点实验室，厦门大学化学系，物理化学研究所，厦门　361005
  • 收稿日期:2000-06-05 修回日期:2000-08-31 发布日期:2001-02-15
  • 通讯作者: 孙世刚 E-mail:sgsun@xmu.edu.cn

The Preparation and Characterization of Platinum Based PbSb Surface Alloy Electrode

Xia Sheng-Qing;Chen Sheng-Pei;Sun Shi-Gang   

  1. State Key Laboratory for Physical Chemistry of the Solid Surface,Department of Chemistry of Xiamen University,Institute of Physical Chemistry, Xiamen　361005
  • Received:2000-06-05 Revised:2000-08-31 Published:2001-02-15
  • Contact: Sun Shi-Gang E-mail:sgsun@xmu.edu.cn

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摘要： 通过电化学方法，在玻碳载体表面制备以Pt、Pb、Sb为主要成分的铂基PbSb表面合金电催化剂.运用电化学循环伏安、石英晶体微天平（EQCM）和扫描隧道显微镜（STM）技术对催化剂电极进行表征.结果表明：酸性溶液中在所制备的表面合金电极上，析氢起始电位负移至－0.45 V，表面合金的起始氧化电位为0.15 V，其稳定性明显高于电催化还原中常用的铅、锑等金属电极.通过EQCM研究表面合金电极的形成过程，结合STM观察和XPS深度剖析，确定电催化剂表面是由粒度均匀的纳米颗粒构成的表面合金层.

关键词: 表面合金, Sb-Pb-Pt/GC, EQCM, STM, XPS

Abstract: The electrocatalysts of platinum based PbSb surface alloy were prepared by electrochemical codeposition under cyclic voltammetric conditions. The structure and properties of these electrocatalysts were studied by techniques of cyclic voltammetry, electrochemical quartz crystal microbalance(EQCM), scanning tunneling microscopy(STM) and Xray photoelectron spectroscopy(XPS). The results demonstrated that the hydrogen evolution on the prepared electrocatalyst was postponed to －0.45 V. i.e., 200 mV has been shifted negatively in comparison with hydrogen evolution at a platinum electrode. In addition,the oxidization of Pb and Sb components in surface alloy was positively shifted to above 0.15 V, which is much higher than the oxidization potential of Pb and Sb metal electrodes. The stability of surface alloy electrode is confirmed to be higher than Pb and Sb metal electrodes that were employed often in organic electrosynthesis. The process of formation of surface alloy was studied in situ by using an EQCM and ex situ by using a STM. The results have converged to illustrate that the surface alloy is constructed of nanoparticles with regular size of about 10 nanometers.The EQCM analysis and XPS depth profiling indicated that the surface alloy is formed on the top layer of a few nanometers in thickness of the SbPbPt/GC electrode.

Key words: Surface alloy, Sb-Pb-Pt/GC, STM, EQCM, XPS