Synthesis of visible-light-active TiO2-based photo-catalysts by a modified sol-gel method

Pure TiO2 and C, N co-doped TiO2 (TiO2: C, N) nanoparticles were successfully synthesized by a modified sol-gel method, using urea as the carbon and nitrogen source. The entire preparation differs from the traditional sol-gel route employed to prepare nano-TiO2 for it does not require the use of any acid or alkali. The characterization results showed that as-prepared samples were nanoparticles with a diameter of 10-30 nm. Most of the carbon incorporated in the TiO2 matrix exists in the form of elemental carbon, and nitrogen was substituted for some of the lattice oxygen atoms. The PL spectra revealed that carbon and nitrogen dopants could enhance the separation of photo-excited electrons and holes, and improve the photo-catalytic efficiency of TiO2. The conjecture was demonstrated by degrading methyl blue under visible light, using the samples as the photo-atalyst. (C) 2012 Elsevier B.V. All rights reserved.