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首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >Foils, Films, and Nanostructured Surfaces: A Comparative XPS and AFM Study of Model Catalyst Surfaces
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Foils, Films, and Nanostructured Surfaces: A Comparative XPS and AFM Study of Model Catalyst Surfaces

机译：箔，薄膜和纳米结构表面：模型催化剂表面的XPS和AFM比较研究

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摘要

A polycrystalline palladium foil and palladium films of various thickness, supported on oxidized silicon wafers, were treated under catalytic conditions in a gas-flow reactor. Their topography and chemical composition were investigated before and after exposure to oxygen and hydrogen by atomic force microscopy and X-ray photoelectron spectroscopy. The results were compared with those of nanostructured palladium model catalysts measured under the same conditions. The nanostructured samples were prepared on oxidized silicon wafers by laser interference lithography and subsequent metal evaporation. Hydrogen and carbon monoxide oxidation were used as test reactions in a quartz reactor at 1 atm pressure and at temperatures up to 600 ℃. All palladium-containing systems were catalytically active after several activation cycles. Nanostructured silver model catalysts were treated in the same way for comparison. The high-temperature treatment at atmospheric pressures in oxygen and hydrogen proved to be highly effective in decontaminating the surface of the catalysts and especially in ridding it of carbon-containing species. Significant changes in the topography of the metal surfaces due to catalytic etching were observed after treatments at 400 and 600 ℃ in the presence of oxygen and hydrogen. While larger palladium clusters on the flat SiO_2 surface tended to sinter and form larger aggregates, the silver particles started to split and spread over the substrate.
机译：负载在氧化硅晶片上的多晶钯箔和各种厚度的钯膜在气流反应器中在催化条件下进行处理。通过原子力显微镜和X射线光电子能谱研究了它们在暴露于氧气和氢气之前和之后的形貌和化学组成。将结果与在相同条件下测得的纳米结构钯模型催化剂进行了比较。通过激光干涉光刻和随后的金属蒸发，在氧化的硅晶片上制备了纳米结构的样品。氢气和一氧化碳氧化被用作石英反应器中的测试反应，压力为1 atm，最高温度为600℃。在几个活化循环后，所有含钯的体系都具有催化活性。以相同方式处理纳米结构银模型催化剂以进行比较。在大气压下在氧气和氢气中进行高温处理已证明在净化催化剂表面，特别是消除含碳物质方面非常有效。在氧气和氢气存在下于400和600℃进行处理后，观察到由于催化腐蚀导致的金属表面形貌发生了显着变化。尽管在平坦的SiO_2表面上较大的钯簇趋于烧结并形成较大的聚集体，但银颗粒开始分裂并散布在基板上。

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