New reactor dedicated to in operando studies of model catalysts by means of surface x-ray diffraction and grazing incidence small angle x-ray scattering.
New reactor dedicated to in operando studies of model catalysts by means of surface x-ray diffraction and grazing incidence small angle x-ray scattering.
复制标题
新型反应器致力于通过表面 X 射线衍射和掠入射小角 X 射线散射对模型催化剂进行操作研究。
DOI：
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发表时间：
2007
影响因子：
1.6
通讯作者：
F. Rieutord
中科院分区：
文献类型：
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作者：
M. Saint;A. Bailly;P. Dolle;R. Baudoing;P. Taunier;S. Garaudée;S. Cuccaro;S. Douillet;O. Geaymond;G. Perroux;O. Tissot;J. Micha;O. Ulrich;F. Rieutord
开发了一种新的实验装置，可以通过表面 X 射线衍射 (SXRD) 和掠入射小角 X 射线散射对化学反应过程中的催化剂表面进行原位研究。 X 射线反应室专为超高真空 (UHV) 和反应气体环境而设计。对样品进行激光束加热；样品温度在 UHV 下达到 1100 K，在有反应气体的情况下达到 600 K。反应器设备允许在受控分压下使用各种完美混合的气体对表面进行动态观察。它可以以两种模式运行：作为压力范围为 1-1000 mbar 的浴反应器，以及作为压力低于 10(-3) mbar 的连续流动池。该反应器与还配备有低能电子衍射和俄歇能谱的超高真空制备室相连。因此，该装置非常适合将原位研究扩展到更复杂的表面，例如外延膜或支撑的纳米颗粒。它提供了跟踪模型催化剂表面在暴露于反应气体期间化学诱导的形态、结构、组成和生长过程的变化的可能性。作为一个例子，Pd(8)Ni(92)(110) 表面结构在几毫巴氢气下和丁二烯氢化过程中通过 SXRD 进行跟踪，同时通过四极杆质谱法监测反应。该实验证明了衍射强度对表面原子和气体分子之间的微妙相互作用的极大敏感性。
A new experimental setup has been developed to enable in situ studies of catalyst surfaces during chemical reactions by means of surface x-ray diffraction (SXRD) and grazing incidence small angle x-ray scattering. The x-ray reactor chamber was designed for both ultrahigh-vacuum (UHV) and reactive gas environments. A laser beam heating of the sample was implemented; the sample temperature reaches 1100 K in UHV and 600 K in the presence of reactive gases. The reactor equipment allows dynamical observations of the surface with various, perfectly mixed gases at controlled partial pressures. It can run in two modes: as a bath reactor in the pressure range of 1-1000 mbars and as a continuous flow cell for pressure lower than 10(-3) mbar. The reactor is connected to an UHV preparation chamber also equipped with low energy electron diffraction and Auger spectroscopy. This setup is thus perfectly well suited to extend in situ studies to more complex surfaces, such as epitaxial films or supported nanoparticles. It offers the possibility to follow the chemically induced changes of the morphology, the structure, the composition, and growth processes of the model catalyst surface during exposure to reactive gases. As an example the Pd(8)Ni(92)(110) surface structure was followed by SXRD under a few millibars of hydrogen and during butadiene hydrogenation while the reaction was monitored by quadrupole mass spectrometry. This experiment evidenced the great sensitivity of the diffracted intensity to the subtle interaction between the surface atoms and the gas molecules.