Ball milling preparation and the effect of calcination temperature on the photocatalytic performance of titanium dioxide

Abstract

The present study investigates the preparation of LiF-doped TiO₂ powders using the ball milling technique, with a focus on optimizing dispersion parameters and assessing the impact of calcination temperature on their photocatalytic activity. TiO₂ powders doped with 2 wt. % LiF were prepared using an industrial attrition mill (Dyno-Mill®) and subjected to heat treatments at different temperatures to control the anatase-to-rutile phase transition. Characterization techniques, including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and UV–Vis spectroscopy using the diffuse reflectance mode (DRS), were employed to evaluate phase composition, surface properties, and optical band gap variations. The photocatalytic performance was assessed through the degradation of methylene blue (MB) under UV–Vis irradiation. The results revealed that the anatase-to-rutile transformation occurred at 700 °C, with a mixed anatase-rutile phase exhibiting enhanced photocatalytic activity. Despite a low BET surface area, the sample calcined at 700 °C for 30 min demonstrated the highest MB degradation rate, outperforming commercial TiO₂ (P25). The improved efficiency is attributed to the synergistic effects between anatase and rutile phases of TiO₂. This study highlights the potential of ball milling as a scalable method for tailoring TiO₂-based photocatalysts with optimized phase composition and photocatalytic properties.