Calcination Conditions on the Properties of Porous TiO₂ Film

Porous TiO₂ films were deposited on SiO₂ precoated glass-slides by sol-gel method using PEG1000 as template. The strongest XRD diffraction peak at 2θ = 25.3° is attributed to [101] plane of anatase TiO₂ in the film. The increases of calcination temperature and time lead to stronger diffraction peak intensity. High transmittance and blue shift of light absorption edge are the properties of the film prepared at high calcination temperature. The average pore size of the films increases with the increasing calcination temperature as the result of TiO₂ crystalline particles growing up and aggregation, accompanied with higher specific surface area. Photocatalytic activity of porous TiO₂ films increases with the increasing calcination temperature. The light absorption edge of the films slightly moves to longer wavelength region along with the increasing calcination time. The mesoporous film calcinated at 500 °C for 2 h has the highest transmittance, the maximum surface area, and the maximum total pore volume. Consequently, the optimum degradation activity is achieved on the porous TiO₂ film calcinated at 500 °C for 2 h.