Date of Award
5-2015
Level of Access Assigned by Author
Campus-Only Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Chemistry
Advisor
Howard Patterson
Second Committee Member
Alice Bruce
Third Committee Member
Scott Collins
Abstract
The surface and photophysical properties of bismuth-based catalysts were determined and correlated with photocatalytic activity. The catalysts themselves were characterized using SEM-EDS, XRD, BET and steady-state luminescence. The photocatalytic potential of these catalysts was determined for their ability to degrade pharmaceuticals 17α-ethinyl estradiol (EE2) and estriol as well as petrochemicals phenol, indole and naphthalene at the ppm level in water. The degree of photodecomposition was evaluated using luminescence spectroscopy and HPLC-MS/MS. This is the first time bismuth-based catalysts have been used to photodegrade the selected organics. Also, this study reports that these bismuth catalysts are more effective at photocatalyzing the selected organics than traditional catalysts such as TiO2. The photocatalytic mechanisms for EE2 and estriol have been compared between samples treated with bismuth based catalysts and TiO2. These bismuth catalysts show great potential as solution to wastewater treatment and environmental remediation.
Some of the bismuth-based catalysts are novel and include terbium. The terbium (III) ion acts as a co-catalyst. Also, energy can be transferred from the bismuth to the terbium (III) ion. These compounds are effective catalysts and their energy transfer behavior may provide applications in photonic devices.
Additional energy transfer studies were conducted on two series of lanthanide- dicyanoaurate coordination polymers that either have or do not have aurophilic interactions. Luminescence and crystallographic studies have been carried out on five different aurophilic and non-aurophilic coordination polymer chain frameworks. In the aurophilic frameworks the close proximity of gold(I) centers on neighboring chains allows for Au-Au interactions to take place that facilitate energy transfer between lanthanides. Terbium- and europium-doped aurophilic frameworks show energy transfer between one of the lanthanide ions and dicyanoaurate centers as observed via luminescence measurements. In the non-aurophilic frameworks the bulky organic cations separate the Au-Au chains, thereby preventing interaction between them, and preventing energy transfer. Also, the O-H vibrational energy in the hydrated (aurophilic) samples can partially quench the Ln signal.
Recommended Citation
Ahern, John C., "Photophysical and Photochemical Investigations of Novel Catalysts and Tunable Energy Transfer Systems" (2015). Electronic Theses and Dissertations. 2300.
https://digitalcommons.library.umaine.edu/etd/2300