Development and photocatalytic testing of TiO2 and TiO2/Fe2O3 nanoparticles using nanolithography and physical vapor deposition

The goal of this research was to create nanoparticles of titanium dioxide (TiO2) and titanium-iron oxide (TiO2/Fe2O3) to be used as catalysts in photochemical reactions. Making TiO2/Fe2O3 catalysts at the nanoscale could yield higher efficiency due to larger surface areas and a smaller band gap, while the inclusion of iron could reduce overall cost. A high vacuum evaporation chamber was designed and built and nanosphere lithography (NSL) was used to produce the nanoparticle arrays. The surface sensitive techniques used to analyze the morphology and composition of the nanoparticle arrays included atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The reactivity of the nanoparticle arrays were analyzed using UV-Vis spectroscopy. A dye (bromothymol blue) was chosen for photocatalytic testing by comparing the rate of decrease in absorbance under an UV lamp. The similarity in the rates (identical within experimental error) between the glass substrate, the TiO2 thin film, TiO2 nanoparticles, TiO2/Fe2O3 thin film, and TiO2/Fe2O3 nanoparticles suggests that catalytic activity cannot be quantified accurately enough in this experiment to positively determine whether the catalysts are aiding in degradation of the bromothymol blue dye and thus warrants further research.