Optimization of Rutile/Anatase Ratio in Titanium Dioxide Nanostructures prepared by DC Magnetron Sputtering Technique

Abstract

Mixed phase rutile/anatase of TiO2 was prepared and studied by a closed field DC magnetron sputtering configuration (CFDCMS). It was found that the contents of rutile increased from the ratio of 38% to 53% as the deposition time increased from 3.5 hours to 4.5 hours.
The photocatalytic activity of the mixed phase rutile/anatase TiO2 was measured by monitoring the degradation of the blue methylene dye in an aqueous solution, under exposure to UV-radiation, using UV-vis absorption spectroscopy. It was proven that the photocatalytic activity in the mixed phase (TiO2) is a function of rutile content reaching a maximum value at 53% rutile. Thus, the effect of synergy between anatase- TiO2 and rutile- TiO2 was observed. It was observed that TiO2 rutile is far less active than TiO2 Anatase. Yet, the presence of the two phases together results in considerable enhancement of the reaction rate when compared to TiO2 anatase alone. This may be due to the increase of the charge carriers’ lifetime allowing for electrons transfer to hydrogen ions and holes transfer to oxygen ions.