The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach
The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach
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DOI：
10.1007/s11244-015-0515-5
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发表时间：
2016-01
影响因子：
3.6
通讯作者：
Fabrizio Orlando;A. Waldner;T. Bartels-Rausch;Mario Birrer;S. Kato;Ming-Tao Lee;C. Proff;T. Huthwelker;A. Kleibert;J. Bokhoven;M. Ammann
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文献类型：
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作者：
Fabrizio Orlando;A. Waldner;T. Bartels-Rausch;Mario Birrer;S. Kato;Ming-Tao Lee;C. Proff;T. Huthwelker;A. Kleibert;J. Bokhoven;M. Ammann
近年来，近环境压力X射线光电子能谱（NAPP）技术发展迅速，成为研究蒸气和液体存在下表面的有力工具。在本文中，我们提出了一个新的室的固体/蒸汽界面的调查有关的环境和大气化学，适合在瑞士光源的NAPP终端站。新的腔室允许在环境相关的温度和相对湿度条件下，在真空和高达20 mbar的近环境压力下，使用软，软和硬X射线进行X射线光电子能谱（XPS）和电子产额近边缘X射线吸收精细结构谱（NEXAFS）。此外，腔室的流管设计使得粘性反应气体的定量给料具有短的压力平衡时间。可获得的光电子动能范围从2到7000 eV。该范围允许确定冰和其他环境材料的表面和体积电子特性，例如金属氧化物和冷冻溶液，这与理解大气化学有关。该仪器的设计和第一个结果的系统非常感兴趣的环境和大气化学界。特别是，近环境压力XPS和NEXAFS，耦合到紫外激光装置，用于研究水的吸附在TiO 2粉末样品。结果与先前提出的水在TiO 2上的吸附模型一致，并且，此外，表明水分子的浓度在UV照射后趋于增加。在第二个例子中，我们说明了如何NEXAFS光谱测量在氯K-边缘可以提供新的洞察力的结构上的低共熔和亚共熔冷冻NaCl溶液在高和低相对湿度，分别表示形成的溶液和固体NaCl相。最后，我们展示了这个新的腔室的资产，用于粘性酸性气体的定量给药，特别是用于冰表面上的甲酸吸收的调查。
Recent years have witnessed fast advancements in near ambient pressure X-ray photoelectron (NAPP) spectroscopy, which is emerging as a powerful tool for the investigation of surfaces in presence of vapors and liquids. In this paper we present a new chamber for the investigation of solid/vapor interfaces relevant to environmental and atmospheric chemistry that fits to the NAPP endstation at the Swiss Light Source. The new chamber allows for performing X-ray photoelectron spectroscopy (XPS) and electron yield near-edge X-ray absorption fine structure spectroscopy (NEXAFS) using soft, tender and hard X-ray in vacuum and in near-ambient pressures up to 20 mbar at environmentally relevant conditions of temperature and relative humidity. In addition, the flow tube design of the chamber enables the dosing of sticky reactive gases with short pressure equilibration time. The accessible photoelectron kinetic energy ranges from 2 to 7000 eV. This range allows the determination of surface and bulk electronic properties of ice and other environmental materials, such as metal oxides and frozen solutions, which are relevant to understanding atmospheric chemistry. The design of this instrument and first results on systems of great interest to the environmental and atmospheric chemistry community are presented. In particular, near-ambient pressure XPS and NEXAFS, coupled to a UV-laser setup, were used to study the adsorption of water on a TiO2powder sample. The results are in line with previously proposed adsorption models of water on TiO2, and, furthermore, indicate that the concentration of water molecules tends to increase upon UV irradiation. In a second example we illustrate how NEXAFS spectroscopy measurements at the chlorine K-edge can provide new insight on the structures of eutectic and sub-eutectic frozen NaCl solutions at high and low relative humidity, respectively, indicating the formation of solution and solid NaCl phases, respectively. Finally, we demonstrate the assets of this new chamber for the dosing of sticky acidic gases and, in particular, for the investigation of formic acid uptake on ice surfaces.