Near-Surface Accumulation of Hydrogen and CO Blocking Effects on a Pd-Au Alloy
Near-Surface Accumulation of Hydrogen and CO Blocking Effects on a Pd-Au Alloy
复制标题
DOI：
10.1021/jp402317h
复制
发表时间：
2013-05-09
影响因子：
3.7
通讯作者：
Fukutani, Katsuyuki
中科院分区：
文献类型：
--
作者：
Ogura, Shohei;Okada, Michio;Fukutani, Katsuyuki
将Pd与Au合金化具有比Pd增强氢溶解度以及对不饱和烃部分加氢等反应的催化活性的显着特点。理解这些现象的关键是澄清近地表区域的氢行为。在目前的工作中，通过将核反应分析与热解吸光谱相结合，对氢进行高分辨率深度分析，我们发现氢大量聚集在近表面区域，并被单晶 Pd70Au30(110) 合金的主体吸收。我们还证明了CO的分子帽效应，其中少量的CO吸附通过阻断氢气的入口/出口通道而极大地改变了氢气的吸收和解吸行为。这些发现有助于理解和控制 Pd-Au 合金和 Pd 相关表面的催化活性，并开辟了一种控制氢在金属表面传输的新方法。
Alloying Pd with Au has remarkable features of enhancement of hydrogen solubility compared to Pd and catalytic activity for reactions such as partial hydrogenation of unsaturated hydrocarbons. A key to understanding these phenomena is clarification of hydrogen behavior in the near-surface region. In the present work, by applying nuclear reaction analysis for high-resolution depth profiling of hydrogen in combination with thermal desorption spectroscopy, we show that hydrogen substantially accumulates in the near-surface region and is absorbed in the bulk of a single-crystal Pd70Au30(110) alloy. We also demonstrate a molecular cap effect of CO, where a small amount of CO adsorption greatly changes the hydrogen absorption and desorption behavior by blocking the entrance/exit channel for hydrogen. These findings lead to understanding and controlling the catalytic activity of the Pd-Au alloy and Pd-related surfaces and also open up a new method to control hydrogen transport across metal surfaces.