After
that, it was proved the O – N band by FT-IR analysis. The peak at 1430 cm-1 could be attributed to the
nitrogen atom embedded in TiO2 network. The absorbance spectra of nitrogen-doped TiO2 were shown
higher than HM-TiO2 and P25-Degussa. It can be shifted to visible light region around 400-570 nm when
used guanidine carbonate was used as N source at the concentration of 0.5M. The photocatalytic activity
under visible light irradiation of nitrogen-doped TiO2 was increased with increasing concentration of
nitrogen source. After nitrogen-doped, the photocatalytic activity was improved greatly compared with
P25-Degussa and HM-TiO2. For optimum condition, 0.5M of guanidine carbonate source was used, it
shown percentage degradation of MB aqueous solution at 80% with visible light irradiation for 1h. The
morphology of nitrogen-doped TiO2 is cubic nanoparticles with 50-500 nm in length.