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

本计画将特别着重于超临界抗溶剂沉淀法制备新型无定形触媒之研究。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，键合信息，氧化态，对分布函数和可能的短程到中程排序。XAS和EM将提供互补信息：XAS提供催化剂的详细体积平均信息，而EM具有更高的空间分辨率，提供更多的局部信息。此外，EM和XAS都可以以原位方式应用，使我们能够动态地跟踪这些非晶材料在实际反应条件下的微观结构演变。丹尼尔赫威斯将开发和应用这种电子显微镜和XAS技术，研究由其他团队成员（Tak Bere和Jack Pitchers）在道达尔资助的一个更大的项目下制备的几种无序混合氧化物催化剂系统。在项目过程中将研究的具体混合氧化物系统是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的工作方式带来新的见解，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.