This work describes an innovative nanosemiconductor system, based on Au-TiO2 for UV photo-assisted oxidation of nitrogen monoxide (NO). The synthesis of these materials was carried out by the sol-gel method. Titanium(IV) isopropoxide and HAuCl4 were the precursors of the photocatalyst, which was prepared in acid conditions. The catalysts were characterized by the following techniques: BET, XRD, UV-vis and dark-field TEM. The evaluation of the photocatalytic activity was performed in situ using an FTIR spectrometer with high sensitivity and a UV spectrometer (365 nm) after 60 min at atmospheric pressure and room temperature. The NO + O-2 Mixture concentration was 150 ppm. The photocatalytic conversion of nitrogen monoxide (NO) was studied by FTIR, which reached 85% in 60 min. The semiconductor type materials exhibited an enhanced photoactivity when compared with our reference TiO2. (C) 2009 Elsevier B.V. All rights reserved.