A Study on Phase Transition of Intrinsic TiO ₂ Based on the Valence Electron Theory

It is well known that titanium dioxide (TiO 2 ) has an irreplaceable role in many aspects, such as paper making, antifouling, medicine, coatings, etc. Anatase is mainly used as a photocatalyst, while rutile is widely used mainly as titanium dioxide. In this study, the intrinsic TiO 2 crystalline structure is constructed using the Materials Studio software. Subsequently, the valence electron distribution and the electron density of the conventional crystalline surfaces of TiO 2 are calculated. The calculations were performed on the basis of the solid and molecular empirical electron theory (EET), in conjunction with the new electron theory of condensed matter. The calculated electron density results suggest the anatase phase generally appears at temperatures of 500[Formula: see text]C or higher. For this reason, 500[Formula: see text]C was chosen as the initial temperature for the phase transition investigation in this work although the precise temperature may vary depending on synthesis conditions. Results showed that phase transformation primarily occurs at the (2 0 0)[Formula: see text]//(1 1 0)[Formula: see text] interface. As temperature increases, the probability of transformation at (1 1 2)[Formula: see text]//(2 1 0)[Formula: see text] decreases, while that at (1 0 1)[Formula: see text]//(1 0 1)[Formula: see text] and (2 0 0)[Formula: see text]//(1 1 0)[Formula: see text] increases.