The Influence of Water and Hydroxyl on a Bimetallic (√3 × √3)R30° Sn/Pt Surface Alloy
The Influence of Water and Hydroxyl on a Bimetallic (√3 × √3)R30° Sn/Pt Surface Alloy
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DOI：
10.1021/jp3112342
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发表时间：
2013-02
影响因子：
3.7
通讯作者：
F. McBride;G. Darling;K. Pussi;C. Lucas;Y. Gründer;M. Darlington;Alexander W. Brownrigg;A. Hodgson
中科院分区：
文献类型：
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作者：
F. McBride;G. Darling;K. Pussi;C. Lucas;Y. Gründer;M. Darlington;Alexander W. Brownrigg;A. Hodgson
锡-铂合金表面在燃料电池反应中表现出显著的活性，氧化和去除了原本会阻碍纯铂反应的一氧化碳。这种所谓的“双功能”机理被认为是由于OH在锡上的吸附和CO在铂上的吸附，减少了位置竞争和CO的中毒。在这项研究中，我们考察了水吸附对有序的锡/铂(111)(√3×√3)R30°表面合金结构的影响，以便将已有的关于锡/铂表面行为的结构数据与吸附物的性质联系起来。用表面X射线衍射法和低能电子衍射法研究了锡/铂的表面结构，并与密度泛函理论模型和现场电化学实验的结构测定结果进行了比较。我们发现，吸附的水在Sn位引起0.16A的向外弛豫，这类似于以前在电化学SXRD测量中归因于OH吸附的结果。我们回顾一下...
Tin–platinum alloy surfaces show a remarkable activity in the fuel cell reaction, oxidizing and removing CO that would otherwise block reaction on pure Pt. This so-called “bifunctional” mechanism has been attributed to OH adsorption on Sn and CO adsorption on Pt, reducing site competition, and poisoning by CO. In this study, we examine the effect of water adsorption on the structure of the ordered Sn/Pt(111) (√3 × √3)R30° surface alloy in order to relate the existing structural data on the behavior of Sn/Pt surfaces to the nature of the adsorbate. The Sn/Pt surface structure was investigated by surface X-ray diffraction (SXRD) and low-energy electron diffraction, and compared to theoretical models obtained from density functional theory and with structural determinations from previous in situ electrochemical experiments. We find that adsorbed water induces a 0.16 A outward relaxation in the Sn position, similar to that previously ascribed to OH adsorption in electrochemical SXRD measurements. We review th...