Date of Completion
Field of Study
Doctor of Philosophy
A reasonable, repeatable synthesis for titania sol gels and the production of titania aerogel was developed and optimized via a statistical design of experiments approach. Optimal conditions were determined by gel quality obtained. The TiO2 aerogel produced was characterized at various calcination temperatures and shown to be active for visible light photocatalysis of a model dye system, methylene blue.
Improvement of the TiO2 for dye degradation reactions was successfully acheieved via the incorporation of a zirconium metal dopant, which showed an increase in overall activity and a reduction in reaction time by 30 minutes over the conventional titania catalyst. Zirconium doped into the material was shown to impact the band gap of the material by shifting the band gap to lower energies, making a more photoactive catalyst, along with the promotion of the development of anatase titania at lower calcination temperatures.
The TiO2 aerogel was used as a support to disperse Cu and Fe through the material for use in the selective, partial oxidation reaction of cyclohexane to cyclohexanol. Preliminary work showed the Cu-TiO2 to be the most active, with optimized conditions leading to >99% conversion of cyclohexane, and >99% selectivity for cyclohexanol.
A hybridization of a mesoporous TiO2 synthesis with the aerogel procedure presented here led to a high surface area, high pore volume material with an ordered mesoporous structure. Various metal dopants (Fe, Cu, Mn, Zr) were incorporated into the material, with all resulting catalysts showing activity for both methylene blue degradation and cyclohexane oxidation. All samples maintained their ordered mesoporous structures and high surface area/pore volumes at elevated temperatures. Unoptimized Cu-UCT-TiO2 aerogels showed higher activity than the unoptimized Cu-TiO2 aerogels, opening the door for development of a more efficient catalyst upon optimization.
Murphy, Steven, "Doped Titanium Dioxide Aerogels for Various Catalytic and Photocatalytic Applications" (2018). Doctoral Dissertations. 1861.