In situ hydrothermal synthesis of visible light active sulfur doped TiO₂ from industrial TiOSO₄ solution

A cost-effective industrial TiOSO₄ solution was employed to fabricate visible light active sulfur-doped titanium dioxide (S-TiO₂) via a facile hydrothermal method. The effect of calcination temperature on morphology, particle size, crystallinity, and photocatalytic property of S-TiO₂ was systematically investigated. Successful incorporation of sulfur into TiO₂ was confirmed by carbon-sulfur analysis, X-ray photoelectron spectroscopy (XPS), and Energy dispersive spectrometer (EDS). The research results demonstrated that calcination temperature significantly impacted the crystallinity, specific surface area, sulfur content, and light absorption properties of S-TiO₂. The catalyst calcined at 400 °C revealed the highest photocatalytic activity, with a rate constant of 0.02408 min^-1, approximately 25 times higher than commercial P25 catalyst. The higher activity was attributed to the synergistic effect of well-crystallized anatase phase, specific surface area, and red shift of spectral absorption.