| The development of new catalytic materials to improve the activity and selectivity of catalytic reactions is an ongoing task for researchers due to the continual demand for cheaper, more energy efficient methods to produce both new and existing products. This dissertation focuses on developing base-metal catalysts for selective hydrogenation reactions. In particular, Ni-Zn intermetallic compounds (which are ordered arrangements of these two elements) are utilized for the selective semi-hydrogenation of acetylene, which is a high-volume industrial reaction that currently requires the use of precious metal catalysts. The poor catalytic properties of pure Ni are greatly improved through the addition of a second base metal, Zn, making the Nibased catalysts behave more like precious metals. While we cannot perform alchemy, turning two base metals into an intermetallic material that behaves like a precious metal might be the closest we can come. The synthesis of well-defined materials and corresponding kinetic measurements utilizing isotopic labeling are combined with density functional theory calculations to highlight the reasons for the enhanced selectivity of Ni-Zn intermetallic catalysts. In situ structuredetermination during catalyst synthesis helps to lay the framework for future intermetallic catalyst development.;Developing new catalytic materials requires detailed knowledge of catalyst structure, because structure is related to function. New characterization methods that have the ability to provide better descriptions of catalysts have the potential to be used in many sub-fields of catalysis. To address this need, this dissertation also focuses on new catalyst characterization techniques using X-ray absorption spectroscopy. We use differential X-ray absorption fine structure to monitor the Ar-induced surface restructuring of Pd nanoclusters at 77 K, highlighting the ability of this technique to probe surface atoms of Pd nanoclusters. Furthermore, we use X-ray absorption near edge structure to identify second-shell coordination in Ti-based transition metal complexes. |
