A series of WOx/TiO2 catalysts containing between 0.6 and 3.4 W at./nm(2) was prepared by pore volume impregnation using ammonium metatungstate solution on crystallized TiO2. Characterization of the solids by X-ray diffraction, Raman and infrared spectroscopy indicated that the W phase was present essentially as a surface W species. The results also suggested an increased degree of condensation of the W phase with increasing W Surface density. The most condensed W species was characterized by a nu(W=O) vibration at 1017 cm(-1). The IR or Raman bands attributed to specific Surface species of the solids were correlated with the abundance of relatively strong Bronsted acid sites and isopropanol dehydration activity. A direct correlation was observed between propene formation rate and the area of the hand at 1017 cm(-1), attributed to the most condensed W species. Furthermore, the abundance of this species appeared to be directly related to that of Bronsted acid sites capable of retaining 2,6-dimethyl pyridine (lutidine) following desorption at 573 K. The behavior of the WOx/TiO2 system was compared with that reported for the corresponding WOx/ZrO2 solids. Higher intrinsic activity (activity per W atom) was observed for WOx/TiO2 system. (C) 2009 Elsevier B.V. All rights reserved.