Preparation of Mesoporous Titania Thin Films and Their Photocatalytic Activity

Abstract

The mesoporous titania was prepared by sol gel method using titania sol and silica sol as precursor. Mesoporous titania thin film was made by removing of silica in TiO₂-SiO₂ composite film using HF leaching. The photocatalytic performance was studied by photodegradation methylene blue in water under UV irradiation. The volume ratio of silica and the calcination temperature influenced the photoactivity. SEM images revealed as the proportion of silica increases, the proportion of the aggregated parts increase and the crystal phase was changed. The BET surface area, pore volume and pore diameter of the TiO₂-SiO₂ 7:3 at 700℃ were found to be 169.4 m²/g, 0.29 cm³/g and 3.8 nm, respectively. The best photocatalytic activity of mesoporous TiO₂ thin films is obtained when the volume ratio of oxide TiO₂-SiO₂ is 7:3 and heated at 900℃, due to the increased crystallinity of anatase and also the existance of anatase and rutile phase.