We report the first demonstration of visible light photocatalytic activity of Sn(2+)-doped TiO(2). The catalysts are prepared from the reaction of titanium butoxide and several tin precursors at 80 degrees C in aqueous solutions. Samples synthesized with SnCl(2) have lower band gaps (red-shifted to the visible region) with respect to anatase TiO(2). The catalysts are isostructural to anatase TiO(2) even at the highest loadings of Sn(2+). When the precursor is changed to SnCl(4), rutile is the predominant phase obtained but no reduction in the band gap is observed. The materials are investigated using X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, IR spectroscopy, photoluminescence, Raman spectroscopy, and other techniques. The majority of surface cation sites are tin, with a fraction of tin also incorporated in the bulk particles. The experiments also indicate the presence of chlorine in the samples, also influencing the optical and catalytic properties as confirmed by comparison to materials prepared using bromide precursors. These catalysts are photocatalytically active for the degradation of organic molecules with rates higher than the standards (P25 TiO(2)) and also evidenced from the generation of hydroxyl radicals using visible light. This protocol could be extended to incorporate Sn(2+) into other oxide semiconductors to prepare photocatalysts with interesting electronic properties. The analysis of the degradation of rhodamine B dye by a de-ethylation mechanism using multivariate chemometric methods is also described. (C) 2011 Elsevier Inc. All rights reserved.