Visible Light Activity of Nitrogen-Doped TiO2 by Sol-Gel Method Using Various Nitrogen Sources

Abstract

In order to improve photocatalytic activities of the pure anatase TiO2 under UV and visible light irradiations, a novel and efficient N-doped TiO2 photocatalyst was prepared by sol-gel method. N-doped titania is prepared using the various nitrogen sources such as: triethylamine, N,N,N’,N’-tetramethylethane-1,2-diamine, ethyldiamine, 1,2-phenylenediamine, propanolamine, and propylenediamine and then the effect of these source on properties of products was investigated. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectra (DRS), energy dispersive spectrometry (EDS) and Fourier transform infrared (FT-IR) techniques. Results indicate that the shifting of absorption edge to visible region compare to the pure TiO2, reducing average size of the TiO2 crystallites, enhancing of lattice distortion of Ti, effective separation of photo-induced electron and hole pair, and improvement of pollutant decomposition under UV and visible light irradiations are due to doping of N in titania. The photocatalytic activities of N-doped TiO2 nanoparticles were evaluated using the photodegradation of methyl orange (MO) under the irradiation of UV and visible light and it confirmed that the photocatalytic activity of N-TiO2 is better than the pure TiO2. By comparing the photocatalytic activities of the N-TiO2 with different nitrogen sources, triethylamine with 2 molar ratio was chosen as the optimum.