Preparation of TiO₂ Photocatalyst by Thermal Spraying with Liquid Feedstock

TiO₂ is the most promising photocatalyst to decompose industrial pollutants in water and air. Compared with TiO₂ powder, the immobilized form is more suitable for application. In the present paper, the nanostructured TiO₂ photocatalyst is formed by thermal spraying with liquid feedstock. The microstructure of the nanostructured TiO₂ is characterized by infrared spectrum, X-ray diffraction, scanning electron microscope, and transmission electron microscope. The photocatalytic performance is characterized with photodegradation of phenol in aqueous solution. The effects of annealing treatment on the crystalline structure of the TiO₂ deposit and the photocatalytic performance are investigated. The results showed that TiO₂ photocatalyst deposited by thermal spraying with liquid feedstock presents nanostructure and anatase crystalline structure mainly. The crystalline structure of TiO₂ deposit can be controlled by post annealing treatment. The as-sprayed TiO₂ coating can decompose phenol in water with the presence of H₂O₂ and UV light. Phenol can be destroyed easily while the complete mineralization takes a little more time. Annealing treatment can improve the photocatalytic performance of TiO₂ coating. The present results revealed that the TiO₂ coating in rutile structure presents a better photocatalytic performance compared with as-sprayed TiO₂ coating in anatase structure.