Simple Way to Enhance the Photocatalytic Activity and Application in Antireflective Coatings for Amorphous TiO2

Small-sized amorphous TiO2 nanoparticles were prepared and deposited on mesoporous SiO2 support via sol-gel method at room temperature. This structure greatly increases the surface areas of the amorphous TiO2 particles, which facilitates the enhancement of photocatalytic activity and preserved the optical performance of the films in the same time. The resultant SiO2&amorphous-TiO2 films afford glasses a maximum transmittance of 99.97% and show a much higher photocatalytic activity than the monolayer amorphous TiO2 film. Surprisingly, the SiO2&amorphous-TiO2 even shows a higher photocatalytic activity than the counterparts with anatase phase. This higher photocatalytic activity is attributed to abundant surface hydroxyl groups and relative loose structure of the amorphous TiO2 nanoparticles, which can help enhance photocatalytic activity through reducing recombination of electron-hole pairs and increase the migration rates of the photoexcited electrons and holes, respectively. And these characteristics may be preferable to crystal structure for enhancing photocatalytic activity. Meanwhile, the coating process is very simple, low cost and conducted at room temperature, which is feasible for polymer substrates.