Photo-Generated Activities of Nanocrystalline TiO2 Thin Films
Transparent nanocrystalline TiO2 thin films with high photocatalytic activity and photo-induced wettability were successfully deposited on a glass slide. Crystal phase transformations and particle size of TiO2 were investigated. Structural and morphological properties of the films were investigated. The photocatalytic activity of the TiO2 films was evaluated. It is found that the photocatalytic activity of TiO2 thin films is significantly decreased by increasing the annealing temperature, which results in a decrease in BET surface area and an increase in crystal size. In addition, increasing film thickness within a certain range significantly improves the photocatalytic activity without causing crack formation of the TiO2 films. Photocatalytic oxidation and photo-induced wettability conversion on the films were investigated. It is found that photo-induced hydrophilic conversion is observed even on the samples annealed at high temperature. The best photo-generated activities are obtained by optimization of dip-coating cycles and annealing temperatures.
KeywordsPhotocatalytic activity Sol–gel process TiO2 films Nanocrystalline
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