V2O5/TiO2(A) catalysts containing 5.1, 8.0, 9.1, 10.5, 11.9, 22.05 and 31.2 wt. % V2O5 were prepared by grafting V2O5 to TiO2(A) support. Bronsted and Lewis acid sites of these catalysts {PTiO2(A), V2O5/TiO2(A)} have been investigated at room temperature by using NH3. The desorption of NH3 from the catalysts was also studied at 50, 100, 200, 300 and 400 degrees C. The adsorption and/or desorption of the probe molecule (NH3) on the support TiO2(A) and on the catalyst V2O5/TiO2(A) were investigated by IR spectroscopy.