Defense Date
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Samy El-Shall
Abstract
Noble metal nanoparticles (NP) exhibit unique physical, chemical, and optical properties compared to their bulk metal counterparts, with applications towards sensing, optics, and catalysis. Nanoparticles have high surface energy resulting from a high fraction of undercoordinated atoms at surface, edge, and corner sites of the particles. This can boost specific catalytic reactions. Moreover, decreasing the size of NPs increases surface-to volume ratio which results in more active catalytic sites, thus increasing catalytic activity. Given NPs high surface energy, they tend to undergo agglomeration, so methods such as capping ligands and np supports have been developed to restrict NP growth. Capping ligands and support mate[1]rials can affect the chemistry of the NPs, so it is important to study the role of ligands and supports in NP-catalyzed reactions. The following report explores palladium nanocatalysts towards two catalytic reactions: CO oxidation and Suzuki cross coupling. These catalytic reactions have applications towards toxic gas removal and pharmaceutical synthesis, respectively. In the case of the CO oxidation project, Pd nanoclusters are supported on a series of metal oxides. The catalytic activities of the ligand-protected Pd clusters versus the unprotected Pd clusters are examined with the aim of elucidating the role of metal-support interaction between the nanocatalyst and the supports towards their respective catalytic activities. The next two projects both explore Pd catalytic systems towards Suzuki cross-coupling. The first catalytic systems studied are the comparison of Pd nanoparticles on two graphitic supports: graphene acid and graphene oxide. An accompanying computational study aims to elucidate each support’s role in facilitating the Suzuki reaction mechanism. The second Suzuki cross-coupling project explores Pd nanoparticles supported on single metal and bimetallic metal-trimesate (MT) compounds, towards Suzuki coupling, to observe differences in catalytic activity from the single metal MTs compared to their bimetallic MT counterparts. Finally, the last project explores utilizing tungsten oxide catalysts supported on silica-doped alumina (SDA) to facilitate the production of branched hydrocarbons. The method of anchoring the tungsten particles across the SDA support utilizes a sacrificial Zn-MOF precursor, followed by pyrolysis and calcination.
Rights
© Michael Moody
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-10-2024