We present the characterization of the physical properties of titanium dioxide powders prepared by the Sol-Gel method. We set the gelling pH to values of 3 (TiO 2-A), 7 (TiO 2-N) and 9 (TiO 2-B) to observe its effect on the properties of the material. In the three cases we obtained nanoparticulated materials with particle sizes between 10 nm and 20 nm. The larger surface areas were obtained at pH 3, which is several times larger than the other synthesized materials. Furthermore, with the gelling condition pH 3, it was possible to synthesize pure anatase phase titania. We present some preliminary results on the test of photocatalytic activity of the synthesized materials in the reduction of nitric oxide.