Preparation and properties of TiO2/fumed silica composite photocatalytic materials

摘要

The fumed silica used to produce the photocatalytic materials. TiO2 gel was obtained using tetrabutyl titanate as a precursor via an acid catalyzed sol-gel process. A novel TiO2/fumed silica porous ceramic material was produced using a 4% phosphoric acid binder. The influence of heating temperature on the crystalline phases of TiO2, and the properties and photocatalytic activity of TiO2 was investigated. The experimental results showed that the transformation of TiO2 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~2g~(-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 TiO2 in a superfine powder state.