Date of Award
Open Access Dissertation
College of Engineering and Computing
High throughput experimentation (HTE) in catalysis has proven useful in expediting materials discovery via parallelized synthesis, characterization, and testing of candidate materials. However, even in a high-throughput manner, the combinatorial explosion of relevant parameters far exceeds our ability to study. To further complicate the problem, a large time investment and great deal of characterization is often required to build an in-depth understanding of catalytic materials. It follows that the field of heterogeneous catalysis is rich with examples of catalytic systems that have been developed using trial and error efforts for which a lot is known but context is lacking. Techniques such as statistical design methodology can be used together with HTE to address this by facilitating more efficient and meaningful exploration of large parameter space problems. In this work, three examples of oxidation catalysis are highlighted where design of experiments was successfully paired with HTE to aid the catalyst development process and uncover novel synthesis-structure-activity relationships. In addition, the prepartion of polyacid functionalized gold nanomaterials for use in Alzheimer’s therapy will be discussed
First, synthesis factors important in the one pot colloidal synthesis of cobalt oxide nanoparticles including surfactant type, heating regimen,reducingagent, and reagent concentrations were studied with a series of factorial designs. Factors were linked to structural parameters including grain size and morphology as well as CO oxidation activity parameters such aslight offtemperature and activation energy. Ultimately, experiments revealed that the density of catalytically active grain boundaries and structure of the CoOx intermediates were the most important factors in enhancing the cobalt oxide reactivity and provided models to tune these variables using synthesis conditions
Second, the optimization of the co-promoter space for Cu-Ag/-Al2O3 catalzed ethylene epoxidation will be discussed, where an emphasis was placed on screening novel promoting materials and using factorial design to develop an understanding of how catalyst structure and promotional effects change with respect to promoter loading and impregnation sequence. It was found that the activity of the catalysts was sensitive to both the co-promoters used and the reactant feed composition which further experimentation revealed was linked to the Cu-Ag alloy behavior as well as the Ag particle size and morphology. Additional studies investigating the ethylene epoxidation activity of novel AgNP-Ag-LSX hybrid materials prepared with various post-synthetic modifications by collaborators will also be discussed.
The partial oxidation of ethane to acetic acid and ethylene will be discussed as a third application in oxidation catalysis. In this work, the structure and activity of doped Mo8V2Nb1 mixed oxide catalysts were investigated. Specifically, the mixed oxide was doped with various redox (Pd,Ni,Ti) and acid (K,Te,Cs) elements at different redox:acid and dopant:host ratios; the effects of which were explored using a threelevel, four-factor full factorial design. An emphasis was placed on understanding how the incorporation of various dopants affected the structure of the mixed metal oxide and the redox:acid dopant balance needed to achieve the desired specificity to various partial oxidation products.
In a slightly unrelated thrust, the development of polyacid functionalized gold nanoparticles and studies of their efficacy as Amyloid-aggregation inhibitors in Alzheimer’s therapy will be discussed. The main focus of this work was leveraging existing polymer science and nanomaterials synthesis knowledge to establish on-demand control of the polymer length and nanoparticle size for the development of functionalized AuNP therapeutics. Additionally, the experimental efforts of the project collaborators led to an understanding of how the PAA-AuNP properties (nanoparticle size and polymer length) changed their ability to inhibit Amyloid-aggregation.
Mingle, K. B.(2018). Combinatorial Study of Oxidation Catalysts: Uncovering Synthesis-Structure-Activity Relationships. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/4712