Ag/TiO(2) sol with narrow particle size distribution was synthesized using TiCl(4) as the starting material. TiCl(4) was converted to Ti(OH)4 gel. The Ag/TiO(2) sol was prepared by a process where H(2)O(2) was added and then heated at 90-97 degrees C. After condensation reaction and crystallization, a transparent sal with suspended Ag/TiO(2) was formed. Ag/TiO(2) was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, contact angle analysis, and X-ray photoelectron spectroscopy. The photocatalytic properties of Ag/TiO(2) film were evaluated by degradation of methylene blue in aqueous solution under UV light irradiation. The suspended Ag/TiO(2) particles were rhombus primary particles with the major axis ca. 40 nm and the minor axis ca. 10 nm. Ag nanoparticles were well dispersed on TiO(2) and the particle size was only 1-2 nm. Ag could restrain the recombination of photo-generated electrons and holes effectively. Transparent thin films could be obtained through dip-coating glass substrate in the sal. The thin film had strong hydrophilicity after being illuminated by UV light. Ag/TiO(2) film showed a significant increase in photocatalytic activity compared to the TiO(2) film. The high amount of surface hydroxyls on Ag/TiO(2) film also played an important role in its photocatalytic activity. (C) 2011 Elsevier Ltd. All rights reserved.
