Date of Award

12-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical and Chemical Engineering and Sciences

First Advisor

D. Andrew Knight

Second Advisor

Rudolf J. Wehmschulte

Third Advisor

Boris Akhremitchev

Fourth Advisor

Michael Fenn

Abstract

Silver nanoparticles, coated with a titania shell were prepared and were shown to be catalytically active for the rapid degradation of organothiophosphate methyl parathion (MeP). Formation of the degradation product, p-nitrophenolate (PNP) was monitored as a function of pH, using UV-Vis spectroscopy, and 31P NMR spectroscopy confirmed the hydrolysis is the predominant pathway for substrate breakdown under non-photocatalytic degradation. We have demonstrated that the unique combination of TiO2 and silver nanoparticles is required for catalytic hydrolysis with good reproducibility. This work represents the first example of MeP degradation using TiO2 doped with AgNP under mild and ambient conditions. It is suggested that higher surface acidity on the surface of Ag@TiO2 initiates the interaction with MeP. The analysis of the catalytic data and a proposed mechanism for organophosphates using Ag@TiO2 will be presented. We also report our efforts to functionalize Ag@TiO2 core-shell nanoparticles with copper bipyridine via organophosphate capping agent. Stabilized core-shell nanoparticles were further interacted with copper ions to give catalytically active species for organophosphates (OPs) degradation. We suggest that Ag@TiO2 may be integrated onto supporting materials for plasmon assisted catalytic transformations.

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