Photostability and optical properties of modified titanium dioxide

Abstract

The influence of different modifiers, P2O5, K2O, Al2O3, SiO2, CeO2, and ZrO2, on the optical properties and photostability of rutile titanium dioxide was studied. The research was aimed at obtaining pigmentary rutile titanium dioxide with the enhanced photostability. The optical properties such as brightness, white tone, and gray tone were improved when titanium dioxide samples were modified with zirconium instead of cerium. Titanium dioxide products modified additionally with Al2O3 displayed improved optical properties by comparison with appropriate titanium dioxide products lacking introduced aluminum. In comparison with unmodified material (∆E * = 21.8), a considerable increase of the photostability of modified titanium dioxide was observed. The lowest photoactivity, in the range of ∆E * = 0.96–2.45, was measured for the TiO2-PKAlSiCe series. A selective leaching method and X-ray diffraction (XRD) analysis were used to determine the distribution of modifiers in titanium dioxide materials. It was concluded that the differences in both photoactivity and optical properties of modified titanium dioxide depend on its phase composition.