Photocatalytic degradation of phenol in aqueous nitrogen-doped TiO2 suspensions with various light sources

In this study, the nitrogen-doped TiO2 polycrystalline powders were synthesized by calcination of the hydrolysis product of tetra-butyl titanate with ammonia. According to the XRD, SEM, XPS, UV-vis absorption and BET analysis, we found that the N-doped TiO2 has mesoporous structures and the nitrogen doping causes the absorption edge of TiO2 to shift to a lower energy region. It is considered that nitrogen atoms in doped TiO2 polycrystalline powder are responsible for the significant enhancement in the doped TiO2 photoactivity under visible light irradiation. We explored the photocatalytic activity of N-doped TiO2 under various irradiation conditions. We found the photocatalytic activity of the N-doped TiO2 with anatase phases was higher than that of the commercial TiO2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation, while Degussa P25 showed higher photocatalytic activity under sunlight irradiation. The FT-IR spectra showed that products of phenol decomposition adsorbed on the catalyst surface after photodegradation of phenol.