Investigation on F–B–S tri-doped nano-TiO2 films for the photocatalytic degradation of organic dyes

F–B–S tri-doped titanium dioxide thin films on common glass were prepared by a modified sol–gel method, in which tetrabutyl titanate (Ti(OC4H9)4) was chosen as the precursor and boric acid (H3BO3), sodium fluoride (NaF), and thiourea (N2H4CS) were employed as boron, fluorine, and sulfur sources, respectively. The microstructure and optical property were characterized by X-ray diffraction, high-resolution field emission scanning electron microscopy, N2 adsorption–desorption isotherms, photoluminescence spectrum, and UV–Vis diffraction reflectance spectroscopy. The photocatalytic performances were evaluated by decomposition of organic dyes in solution. The experimental results revealed that the F–B–S tri-doped TiO2 thin film was composed of uniform round-like nano-particles with the size range of 5–8 nm. F–B–S tri-doping not only significantly promoted the UV-induced photodecomposition activities of TiO2 films but also extended the optical response of TiO2 red shift to visible light region, herein improving the visible light-induced degradation of organic dyes. The improvement mechanism by F–B–S tri-doping was also discussed.