Electron Microscopy and XAS Studies of Novel Catalysts Based on Amorphous Materials

本项目将重点研究超临界反溶剂沉淀法制备新型非晶催化剂。与晶体材料相比，非晶材料的结构细节及其在催化反应中的作用的研究更具挑战性。EM和XAS的成像，衍射和光谱能力提供了一系列技术来提取这些非晶材料的关键信息，如元素分布，键信息，氧化态，对分布函数和可能的中短范围排序。XAS和EM将提供互补的信息：XAS提供催化剂的详细平均体积信息，而EM具有更高的空间分辨率，可以提供更多的局部信息。此外，EM和XAS都可以原位应用，使我们能够动态跟踪这些非晶材料在实际反应条件下的微观结构演变。Daniel Hewes将开发并应用这种电子显微镜和XAS技术来研究由其他团队成员（Tak here和Jack Pitchers）在道达尔资助的一个更大的项目中制备的几种无序混合氧化物催化剂体系。在项目过程中要研究的具体混合氧化物体系是CeZrOx、FeMoOx和AlSiOx。在每种情况下，在这些系统上获得的结构数据将与它们的催化剂性能特征相关联。这些研究将为无序催化剂如何运作带来新的见解，并为开发更好的混合氧化物催化剂配方提供机会。

This project will specifically be focusing on the study of novel amorphous catalysts prepared by supercritical antisolvent precipitation. Compared to crystalline materials, the structural details of amorphous materials, and their role in catalytic reactions are more challenging to study. The imaging, diffraction and spectroscopic capabilities of EM and XAS provide a range of techniques to extract critical information on these amorphous materials, such as elemental distribution, bonding information, oxidation state, pair distribution functions and possible short- to mid-range ordering. XAS and EM will provide complementary information: XAS provides detailed volume averaged information on the catalysts, while EM, with its higher spatial resolution, provides more localised information. In addition, both EM and XAS can be applied in an in-situ manner allowing us to dynamically follow the microstructural evolution of these amorphous materials under actual reaction conditions. Daniel Hewes will be developing and applying such electron microscopy and XAS techniques to study several disordered mixed oxide catalyst systems prepared by other team members (Tak Bere and Jack Pitchers) under a larger project funded by Total. The specific mixed oxide systems to be studied during the course of the project are CeZrOx, FeMoOx and AlSiOx. In each case, the structural data acquired on these systems will be correlated with their catalyst performance characteristics. Such studies will bring new insights into how disordered catalysts operate and provide opportunities for developing better mixed oxide catalyst formulations.