Oxidation of NO in gas phase by Au–TiO2 photocatalysts prepared by the sol–gel method

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 + O2 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.