Simple and Effective Preparation of N-doped TiO_2 Nanocrystallites with Visible-light Activities

N-doped Ti02 nanocrystallites were prepared by mixing tetrabutyl titanate and urea in ethanol, then calcined at a certain temperature and time. The prepared powders were characterized by XRD, XPS and UV-Vis absorbance spectra and their photocatalytic activities under visible-light irradiation were also investigated. N-doped TiO2 prepared by this method could make its absorbance shoulder evidently shift into visible-light region. Also it has high photocatalytic activities in the degradation of methylene blue under visible-light irradiation.