In this study, preparation of Sn doped (0–30 mol % Sn) TiO2 dip-coated thin films on glazed porcelain substrates via sol–gel process have been investigated. The effects of Sn content on the structural, optical, and photo-catalytic properties of applied thin films have been studied by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), field emission SEM (FE-SEM), and high resolution transmission electron microscopy (HR-TEM). Surface topography and surface chemical state of thin films were examined by atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). XRD patterns showed an increase in peak intensities of the rutile crystalline phase by increasing the Sn dopant. The prepared Sn-doped TiO2 photo-catalyst films showed optical absorption edge in the visible light area and exhibited excellent photo-catalytic ability for degradation of methylene blue solution under UV irradiation. The result shows that doping an appropriate amount of Sn can effectively improve the photo-catalytic activity of TiO2 thin films, and the optimum dopant amount is found to be 15 mol%. The Sn4? dopants substituted Ti4? in the lattice of TiO2 and increased surface oxygen vacancies and the surface hydroxyl groups. TEM results showed small increase in planar spacing (was detected by HR-TEM caused by Sn dopants in titania based crystals).
