EFFECT OF Sb DOPING ON THE STRUCTURAL, OPTICAL, AND VISIBLE-LIGHT PHOTOCATALYTIC PROPERTIES OF TiO₂ NANOPARTICLES

Abstract

Titanium dioxide (TiO₂) is an effective photocatalyst but its limited visible-light response restricts its photocatalytic efficiency. In this study, Sb-doped TiO₂ nanoparticles containing 0.1–5% Sb were synthesized by a coprecipitation method using TiCl₄ and SbCl₃ as precursor materials. The prepared nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy, fluorescence spectroscopy, and Brunauer–Emmett–Teller (BET) surface-area analysis. XRD results confirmed that all samples retained the anatase phase, with crystallite sizes ranging from 13.6 to 19.2 nm, while SEM showed irregular particles of approximately 25–40 nm. The BET surface area varied with Sb concentration, reaching a maximum of 69.220 m²/g for 0.5% Sb–TiO₂. UV–visible measurements showed that Sb incorporation extended the optical absorption of TiO₂ toward the visible-light region. Photocatalytic activity was evaluated under visible-light irradiation using terephthalic acid as a fluorescent probe. Among the investigated samples, 0.1% Sb–TiO₂ exhibited the highest photocatalytic activity and performed better than both pure TiO₂ and commercial Degussa P25 under the applied conditions. Scavenger experiments further indicated the involvement of hydroxyl (OH•) and superoxide anion (O₂•⁻) radicals in the photocatalytic process. Overall, the results demonstrate that controlled Sb incorporation, particularly at 0.1%, effectively improves the visible-light photocatalytic performance of TiO₂ nanoparticles.