In-House X-ray Absorption Spectrometer

x射线吸收光谱（XAS）是在几乎任何条件下（固体、液体、溶液、无定形、晶体、高温、低温、高压等）表征多种形式的功能分子和材料（特别是催化剂）的有用技术。XAS是特定于元素的，它提供了所选元素的电子结构和原子连通性的信息，在很大程度上不受材料其余部分的干扰。这使得它在研究复杂的催化反应时特别受欢迎。尽管它很实用，但XAS一直被执行测量的困难所阻碍，直到最近，这些测量只能在为数不多的同步辐射设施中进行。在这些设施中，获得测量时间的过程非常耗时（必须提前一年左右申请），并且可用或授予的测量时间有限（通常只有3 - 5天），由于缺乏测量时间，经常妨碍常规样品的测量和重要催化过程的长期原位测量。这通常会阻碍有用的项目的开展和有趣的工作的发表。自2015年以来，内部XAS光谱仪已经上市，能够在不使用同步加速器设施的情况下测量高质量的XAS光谱。斯图加特大学还没有这样的仪器，它将填补目前表征催化剂和功能材料的仪器能力方面的一个限制进步的空白。该仪器将使某些实验成为可能（例如，长时间的数周）（多相催化剂的原位测量，空气敏感均相催化剂系统的原位测量），到目前为止，这些实验要么是不可能的，要么是不切实际的。毫无疑问，这也将导致更多，更高质量和更快的出版物，否则永远不会出现通过消除同步加速器光束线获得测量时间的障碍。在本提案中，我们建议配备一个内部x射线吸收光谱仪，用于固相和液相催化剂的原位反应器，能够在催化剂的整个生命周期内测量二氧化碳转化，大环和聚合物合成以及对映选择性有机反应的催化剂的x射线吸收光谱。这将使我们了解现有工业催化剂的失活机制，监测催化剂在实际反应条件下的活性物质，并了解反应过程中物质的电子结构。这样的系统将为现有催化剂系统提供新的见解，并使新技术进入实际应用。

X-ray absorption spectroscopy (XAS) is a useful technique for characterizing functional molecules and materials (especially catalysts) in many forms under nearly any conditions (solid, liquid, solution, amorphous, crystalline, high temperature, low temperature, high pressure, among others). XAS is element-specific and gives information about the electronic structure and atomic connectivity of a chosen element largely without interference from the rest of the material. This makes it especially beloved for studying complex catalytic reactions. Despite its utility, XAS has been held back by the difficulty of performing the measurements, which could until recently only be performed at one of a handful of synchrotron radiation facilities. The time-consuming process of obtaining measurement time (which must be applied for around a year in advance) and the limited amount of measurement time available or granted (often only 3 – 5 days) at such facilities frequently prevents both the measurement of routine samples and long-term in situ measurements of important catalytic processes, due to a lack of measurement time. This often prevents useful projects from being carried out and interesting work from being published.Since 2015, in-house XAS Spectrometers have been on the market that are capable of measuring high quality XAS spectra without the use of synchrotron facilities. Such an instrument is not available at the University of Stuttgart and would fill a progress-limiting gap in the current instrumental capabilities for characterization of catalysts and functional materials. This instrument would make certain experiments possible (e.g. long-term weeks-long) in situ measurements of heterogeneous catalysts, in situ measurements of air-sensitive homogeneous catalyst systems) that up until now were either impossible or impractical. It will also undoubtedly result in more, higher quality and faster publications that would never have otherwise appeared by removing the barrier of obtaining measurement time at synchrotron beam-lines.In this proposal, we propose to outfit an in-house X-ray absorption spectrometer with in situ reactors for both solid and liquid phase catalysts capable of measuring X-ray absorption spectra of catalysts for CO2 conversion, macrocycle and polymer synthesis, and enantioselective organic reactions over the course of the full catalyst lifetimes. This will allow us to understand the mechanisms of deactivation of existing industrial catalysts, monitor the active species of catalysts under real-life reaction conditions, and understand the electronic structure of species during reaction. Such a system will both provide new insights into existing catalyst systems and enable new technologies to enter practical use.