Synthesis, characterization, and theoretical study of N, S-codoped nano-TiO<inf>2</inf>with photocatalytic activities

• Key Words:Nitrogen compounds;Azo dyes - Calculations - Density functional theory - Doping (additives) - Electronic structure - High resolution transmission electron microscopy - Light absorption - Nanoparticles - Photocatalysis - Sol-gel process - Sol-gels - Sulfur dioxide - Titanium dioxide - Transmission electron microscopy - X ray diffraction;Degradation of methyl oranges - Diffuse reflectance spectrum - Electronic delocalization - First-principles calculation - Photocatalytic activities - Photocatalytic performance - Red shift - Theoretical calculations
• Abstract:Nitrogen and sulfur doped titanium dioxide photocatalysts were prepared by the sol-gel method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-visible diffuse reflectance spectra (DRS). Photocatalytic activities of the samples were investigated on the degradation of methyl orange (MO). The effect of the dopants on the electronic structure of TiO<inf>2</inf>was studied by the first-principles calculations based on the density functional theory (DFT). The orbital hybridization resulted in energy gap narrowing and electronic delocalization in the crystal of doped TiO<inf>2</inf>. Mobile electrons of varied energetic states could offer enhanced electron transfer, together with optical absorption improvement. The results show that the doping elements of N and S play a cooperative role in the modification of electronic structure, which enhances the photocatalytic performance. The experimentally observed absorption edges of N-doped TiO<inf>2</inf>, S-doped TiO<inf>2</inf>, and N, S-codoped TiO<inf>2</inf>are 420, 413, and 429 nm, respectively, which can be explained by the theoretical calculation results. &copy; 2011 University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.<br/>
• Volume:18
• Issue:5
• Translation or Not:no