Dye decomposition on P25 with enhanced adsorptivity

The preparation method and the activity of the TiO₂-P25/N doped photocatalyst based on commercial titanium dioxide (TiO₂ Aeroxide® P-25 Degussa, Germany) are presented. For the TiO₂-P25/N preparation TiO₂-P25 and gaseous ammonia were kept in a pressure reactor (10 bars) for 4 hours at the temperature of 200°C. This modification process changed the chemical structure of the TiO₂ surface. The formation of NH₄⁺ groups was confirmed by the FTIR measurements. Two bands in the range of ca. 1430 - 1440 cm^-1 attributed to bending vibrations of NH₄⁺ could be observed on the FTIR spectra of the catalysts modified with ammonia and the band attributed to the hydroxyl groups at 3300 - 3500 cm^-1, which were not reduced after N-doping. The photocatalytic activity of the photocatalysts was checked through the decomposition of two dyes under visible light irradiation. The modified TiO₂ thus prepared samples were more active than TiO₂-P25 for the decomposition of dyes under visible light irradiation.