Effect of Nitrogen Doping on the Photocatalytic Properties of TiO2

A series of nitrogen-doped TiO2 were prepared through a simple sol-solvothermal method. The catalysts were characterized by BET, XRD, SEM-EDS, Raman, XPS, FTIR, UV-Vis, etc. The results show that N-TiO2 photocatalyst has a larger specific surface area, stable anatase phase, and narrow forbidden band energy (3.17-3.24 eV). The N-doped TiO2 has more oxygen vacancies (OVs) than pure TiO2, as confirmed by results such as XPS and ESR. The photocatalytic evaluation results show that the decolorization of methyl orange reached 99.03 % over the 3 % N-doped TiO2, which is 40 % higher than that of pure TiO2. Meanwhile, 3 % N-doped TiO2 exhibited a faster MO mineralisation rate than TiO2. After repeatedly used for 5 times, the photocatalyst 3-N-TiO2 still showed high activity in the degradation of MO. The improvement of the visible light performance of the N-TiO2 photocatalyst could be attributed to the introduction of N in TiO2 to generate new N 2p energy levels and rich OVs.