Vanadia and titania/vanadia sols synthesized by the polyol method were used to prepare TiO2-supported catalysts. Both the modification of the V2O5 sol with a low amount of water and the use of a TiO2/V2O5 Sol induced a reliable adhesion between the preformed active phases and the support, thus leading to stable catalysts. Despite the low amount of vanadium introduced in studied samples, V2O5/TiO2/WO3 catalysts were active in the o-DCB oxidation. The best results were obtained with 0.36-V2O5-TiO2 catalyst, prepared by direct impregnation with colloidal TiO2/V2O5-mixed oxides. The electroacoustic analysis indicated that the support does not show any particular electrostatic affinity for any studied sot; therefore, the higher ability of TiO2/V2O5 Sol to form stable vanadium active species may possibly be explained by a better chemical affinity with the support. (c) 2007 Elsevier B.V. All rights reserved.