In-situ N-doped mesoporous black TiO2 with enhanced visible-light-driven photocatalytic performance

Abstract

In-situ N-doped mesoporous black TiO2 photocatalyst is fabricated by a facile sol-gel method combined with an in-situ solid-state chemical reduction technique, using urea as nitrogen resource. The N-doped mesoporous black TiO2 possesses high surface area of 96 m2 g−1, large pore size of 5.4 nm and narrow band gap of 2.05 eV. Meanwhile, the optical absorption extends to visible light region because of Ti3+ and N co-doping. The N-doped mesoporous black TiO2 exhibits higher photocatalytic activity than that of others under visible light irradiation for photocatalytic degradation of methyl orange (MO) and rhodamine B (RhB), which is up to 93.27% and 93.64%, respectively. The enhancement is ascribed to the synergistic effect of the N and Ti3+ co-doping extending the visible light absorption, the separation efficiency of photogenerated charge carriers, and the mesoporous structure with large surface area offering more surface active sites, which is beneficial for improving the photocatalytic activity.