Date of Award

Spring 5-11-2019

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor

Howard Patterson

Second Committee Member

Scott Collins

Third Committee Member

Elizabeth Stemmler

Additional Committee Members

Alice Bruce

Matt Brichacek

Carl Tripp

Abstract

Heterogeneous semiconductor photocatalysis, of interest for water splitting and environmental remediation applications, uses light to drive reactions. Metal oxide and sulfide semiconductors have been previously studied but have limitations that include large band gap energies and high rates of recombination. Bismuth oxyhalides (BiOX) are an emerging class of photocatalysts with tunable band gaps and low rates of recombination due to their unique crystal structures. Studies of BiOX photocatalytic activity have largely focused on removal of azo dyes from aqueous solutions, with little attention paid to degradation byproducts. Furthermore, these catalysts have not been explored as a means to conduct organic transformations including C-C bond formation. In this work, BiOX solids were evaluated for the photocatalytic degradation of the persistent organic pollutants atrazine and ibuprofen. Work with atrazine, degraded with BiOCl and Cu-BiOCl under 254 nm light conditions was explored for •OH radical, O2•- and electron hole contributions to the reaction pathway. The reaction rates and products generated by the photocatalytic degradation of ibuprofen using BiOCl were characterized and a degradation mechanism was proposed. The photocatalytic degradation studies suggest the high reactivity of electron holes in the valence band of BiOCl play an important role in the observed degradation efficiency. Finally, BiOI photocatalysts were evaluated for their potential to drive coupling reactions under visible light irradiation. It was found that coupling products of cyclohexyl halides and toluene are achieved in high yield, but cyclohexane dehydrodimerization reactions proceeded with low yields

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