A series of WO x /TiO 2 catalysts containing between 0.6 and 3.4Wat./nm 2 was prepared by pore volume impregnation using ammonium metatungstate solution on crystallized TiO 2 . 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 ν(WO) vibration at 1017cm −1 .The IR or Raman bands attributed to specific surface species of the solids were correlated with the abundance of relatively strong Brønsted acid sites and isopropanol dehydration activity. A direct correlation was observed between propene formation rate and the area of the band at 1017cm −1 , attributed to the most condensed W species. Furthermore, the abundance of this species appeared to be directly related to that of Brønsted acid sites capable of retaining 2,6-dimethyl pyridine (lutidine) following desorption at 573K. The behavior of the WO x /TiO 2 system was compared with that reported for the corresponding WO x /ZrO 2 solids. Higher intrinsic activity (activity per W atom) was observed for WO x /TiO 2 system.