In this paper, Sn-doped TiO2 photocatalyst was prepared and immobilized on a glass substrate using an about-to-gel SiO2 sol as a nanoglue. The characterization of the Sn-doped TiO2 by XRD showed that 5% Sn content is formed by anatase and rutile crystallites. Characterization of the nanoglued photocatalyst by the BET measurement, TEM, and SEM showed that the photocatalyst was a nanoporous material with a high-surface area. The sn-doped TiO2 was uniformly dispersed within the three-dimensional network of the silica in the form of nanoparticles. The nanoglued photocatalyst showed high photocatalytic activity during the degradation of penicillin under UV light. The effect of different Sn content on the amount of hydroxyl radical was discussed by using salicylic acid as probe molecules. The results show that an appropriate amount of Sn dopant can greatly increase the amount of hydroxyl radicals generated by TiO2 nanoparticles, which are responsible for the obvious increase of photocatalytic activity. (C) 2008 Elsevier B.V. All rights reserved.