Nitrogen-doped TiO2 nanomaterials were fabricated from hydrogen titanate prepared by hydrothermal method. The
starting materials with difference nitrogen sources and concentration were studied. The samples were characterized
by X-ray diffraction (XRD), transmission electron microscope (TEM), BET surface area, Fourier Transform infrared
spectrometer (FT-IR) and UV-vis absorption spectra by UV–VIS spectroscopy. The photocatalytic activity was
investigated by degradation of methylene blue aquoeus solution under visible light irradiation. The highest
photocatalytic activity of nitrogen-doped TiO2 was gotten from the sample in which 0.5M guanidine carbonate was
used as nitrogen source. Compared with pure TiO2 (from hydrothermal method) and P25-Degussa, the wavelength
range of nitrogen-doped TiO2 was shifted to visible light while pure TiO2 and P25-Degussa were showed in
ultraviolet region.