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Catalytic Properties of Novel Microporous Minerals

Cymes, Brittany Allison
http://orcid.org/0000-0002-2020-3476
http://rave.ohiolink.edu/etdc/view?acc_num=miami1587730697926361

Abstract Details

2020, Doctor of Philosophy, Miami University, Geology and Environmental Earth Science.
Modern civilization as we know it today could not exist without heterogeneous catalysis as it underpins all development in applied chemistry, materials science, and environmental geochemistry. Catalysts allow important chemical reactions such as the production of agricultural fertilizer, the formation of petrochemicals, and the breakdown of environmental pollutants to occur with lower energy thresholds. Catalysts comprise a diverse group of materials but none quite as important as porous solids, which optimize surface area, facilitate catalyst recyclability, and impart important selective properties. Many porous materials are naturally occurring minerals such as transition metal oxides, phyllosilicates, zeolites or complex compounds of minerals. This dissertation relates efforts to create and explore novel mineral catalysts whose catalytic properties are directly related to their microporosity, that is, minerals whose pores are less than 2 nanometers in diameter. In the first project, cryptomelane - a manganese oxide with a square tunnel-based framework - was synthesized in the absence and presence of an aqueous growth medium and doped with europium during and after crystallization to investigate Eu's effects on cryptomelane's physical, chemical, and catalytic properties in a temperature-dependent oxidation reaction. It was determined that the position of Eu in the cryptomelane framework strongly affected its catalytic activity. In the second project, sepiolite - a phyllosilicate mineral with a ribbon-like crystal structure and high specific surface area - was modified with manganese and europium prior to in-situ growth and deposition of nanocrystalline titanium dioxide to investigate the effects of support-doping vs. catalyst-doping in a photocatalytic reaction under different ultraviolet radiations. It was determined that phyllosilicate support promoters have variable behavior during multi-step catalyst preparation which ultimately impacted the photocatalytic activity of the primary catalyst. In the third project, cavansite - a phyllosilicate mineral with redox-sensitive vanadium centers in a zeolite-like framework - was investigated for the first time as a catalyst and also for the first time using electron microscopy. It was determined that cavansite may have selective activity for selective partial oxidation of ethanol at elevated temperatures. In addition, unreported cleavage planes were resolved using scanning electron microscopy in two perpendicular directions.
Mark Krekeler (Advisor)
John Rakovan (Committee Member)
Claire McLeod (Committee Member)
Catherine Almquist (Committee Member)
Peter Heaney (Committee Member)
136 p.
Chemical Engineering; Environmental Geology; Materials Science; Mineralogy
catalysis, porous minerals, transmission electron microscopy, applied mineralogy, mineral synthesis, phyllosilicates, cryptomelane, sepiolite, cavansite, titanium dioxide, manganese, europium, vanadium

Recommended Citations

Citations

  • Cymes, B. A. (2020). Catalytic Properties of Novel Microporous Minerals [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1587730697926361

    APA Style (7th edition)

  • Cymes, Brittany. Catalytic Properties of Novel Microporous Minerals. 2020. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1587730697926361.

    MLA Style (8th edition)

  • Cymes, Brittany. "Catalytic Properties of Novel Microporous Minerals." Doctoral dissertation, Miami University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1587730697926361

    Chicago Manual of Style (17th edition)

miami1587730697926361
151
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This open access ETD is published by Miami University and OhioLINK.