Preparation and properties of TiO_2/fumed silica composite photocatalytic materials

摘要

The fumed silica used to produce the photocatalytic materials. TiO_2 gel was obtained using tetrabutyl titanate as a precursor via an acid catalyzed sol-gel process. A novel TiO_2/fumed silica porous ceramic material was produced using a 4% phosphoric acid binder. The influence of heating temperature on the crystalline phases of TiO_2, and the properties and photocatalytic activity of TiO_2 was investigated. The experimental results showed that the transformation of TiO_2 from anatase to rutile began at 725°C. The photocatalytic porous ceramic materials which were heated at 700–800°C exhibited high tensile strength (7.67–8.18 MPa), high specific surface areas (25.01–25.07 m~2 g~(-1)), high anatase content (>90%) and good photocatalytic activity, as confirmed by the complete degradation of a 10 mg·L~(-1) methyl orange solution using 15W·m~(-2) with ultraviolet light irradiation over 24 h. This technique successfully overcomes the difficulties in separation and recovery commonly associated with most commercial TiO_2 in a superfine powder state.