Photosensitization of TiO2 by Ag2S and its catalytic activity on phenol photodegradation

A process of TiO2 photosensitization by coupling it with a narrow band gap semiconductor has been investigated here. Distinct TiO2/Ag2S nanocomposites were prepared by a single-source decomposition method. After sensitization, the TiO2 materials were evaluated as photocatalysts on the degradation of aqueous phenol solutions. The experimental results show that the nanocomposites photocatalytic activity is related with the existence of Ag2S over the TiO2 surface. The best catalytic results, for phenol photodegradation, were obtained using a TiO2/Ag2S material with a surface Ti/Ag atomic ratio equal to 2.40. With this material the complete photodegradation of a 0.20 mM phenol solution was achieved within 90 min, which is considerably faster when compared with the use of TiO2. The occurrence of main degradation byproducts was also investigated. (C) 2009 Elsevier B.V. All rights reserved.