Preparation and Properties of Sulfur-Doped Visible-Light Response S-TiO2/SiO2 Photocatalyst

S-doped visible-light response S-TiO2/SiO2 photocatalyst samples were prepared by a hydrolysis-precipitation method. The photocatalytic activity was investigated by the degradation of phenol. The separability of S-TiO2/SiO2 was determined by sedimentation. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy, X-ray diffraction, transmission electron microscopy, and N-2 adsorption-desorption were used for catalyst characterization. The results showed that cationic S6+ was incorporated into TiO2 lattice and substituted part of Ti4+ . S-TiO2/SiO2 with suitable S-doping exhibited higher activity under ultraviolet light, visible light, and solar irradiation. S-TiO2/SiO2 exhibited better decanting ability and less deactivation. Doped-S can form a new bond of Ti-O-S above the valence band of TiO2 to extend the adsorption edge to 450-550 nm, and can increase amount of surface OH- of TiO2. The addition of SiO2 can form a new bond of Ti-O-Si, beneficial to the high dispersion, and larger surface area of S-TiO2/SiO2.