Bridging Homogeneous and Heterogeneous Catalysis: In-Situ Characterization and Theory of Supported Metal Complexes

催化在化工制造、能源转化和环境保护中发挥着核心作用。一个主要的挑战是在均相和非均相催化剂之间架起桥梁：支撑上的金属配合物说明了它们之间的一些最佳连接。然而，对于这些催化剂的原位表征技术的缺乏，使得这些催化剂的结构可以在其工作状态下进行研究。本研究的目标是开发和演示原位光谱和流动反应器技术的方法，用于在气相反应物（如石蜡和烯烃）存在的情况下研究氧化物负载的过渡金属络合催化剂。这些技术包括原位红外光谱、x射线吸收近边缘结构和扩展x射线吸收精细结构光谱。理论方法将利用密度泛函理论。催化剂将包括氧化物负载的Ta， Cr和Zr配合物和一种新的沸石负载的Pt配合物。综合表征数据和理论将允许确定原子尺度催化剂结构和催化反应速率如何取决于吸附物和载体的结构和组成，以及反应条件。这是鉴定反应中间体和建立反应机制的绝佳机会。最大的挑战将是预测催化活性。这项研究将通过一项指导计划产生更广泛的影响，该计划将来自代表性不足群体的学生纳入研究项目。一个跨学科的IGERT项目已经到位，重点是纳米科学和技术。

Catalysis plays a central role in chemical manufacturing, energy conversion, and environmental protection. A central challenge is to bridge homogeneous and heterogeneous catalysts: metal complexes on supports illustrate some of the best connections between them. However, there is a striking lack of their characterization with in situ techniques, which allow the structures of these catalysts to be investigated in their working state. The goal of this research is to develop and demonstrate methods of in situ spectroscopy and flow reactor techniques for investigation of oxide-supported transition metal complex catalysts in the presence of gas-phase reactants, such as paraffins, and olefins. The techniques include in situ IR, X-ray absorption near edge structure, and extended X-ray absorption fine structure spectroscopies. Theoretical approaches will utilize density functional theory. The catalysts will include oxide-supported Ta, Cr, and Zr complexes and a new zeolite-supported Pt complex. The combined characterization data and theory will permit determination of how the atomic-scale catalyst structure and the rates of the catalytic reactions depend on the structure and composition of the adsorbate and the support, as well as the reaction conditions. There is an excellent opportunity to identify reactive intermediates and establish reaction mechanisms. The grand challenge will be to predict catalytic activities. The research will have strong broader impacts through a mentorship program that involves students from underrepresented groups in research projects. An interdisciplinary IGERT program is in place that focuses on nanoscience and technology.