Thermogravimetric and UV–vis spectroscopic studies of chromium redox reactions in rutile pigments

Abstract

In this study undoped and Cr, Sb or Mo doped TiO 2 were synthesized by polymeric precursor method and characterized by X-ray diffraction, UV-VIS spectroscopy, infrared spectroscopy and thermogravimetry (TG). The TG curves showed a continuous mass loss assigned to the hydroxyl elimination and Cr 6+ reduction. Doped TiO 2 samples showed a higher mass loss assigned to water and gas elimination at lower temperatures. In these doped materials a decrease in the anatase-rutile phase transition temperature was observed. After calcination at 1,000 °C, rutile was obtained as a single phase material without the presence of Cr 6+ .