Photocatalytic and self-cleaning properties of glazed ceramic tiles coated with TiO2 and Al-doped TiO2 thin films

The undoped and Al-doped TiO2 coatings on glazed ceramic tiles have been prepared by sol-gel and spray coating process. The samples were heat treated at 550 degrees C with 15-min soaking. The coatings were characterized for microstructure, surface morphology, elemental analysis, and thickness using the grazing-incidence X-ray diffraction (GIXRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscope (SEM), respectively. For the Al-doped TiO2 coating, only anatase phase was identified, but the undoped TiO2 coating exhibited a mix of anatase and rutile. The Al-doped TiO2 coating exhibited a homogeneous and relatively crack-free morphology, but the undoped TiO2 coating had significant cracks. The elemental analysis confirmed Ti, O, and Al in the coatings. The undoped and Al-doped TiO2 films had uniform thickness. The photocatalytic decomposition of methylene blue and the photo-induced wettability of the samples were investigated using the UV-Vis spectrophotometer and water contact angle measurement, respectively. The Al-doped TiO2 coating exhibited more efficient photocatalytic activity and hydrophilicity than the other samples after the UV irradiation.