from first principles PP-I-1

PP-V-12Study of Free Charge Carrier Distribution on the Surface of Titania-BasedPhotocatalystsSamoilov A.V., Nikitich M.P., Vodyankin A.A., Vodyankina O.V.Tomsk State University, Tomsk, Russiaalekzander.samoilov@gmail.comApplication of TiO 2 -based photocatalysts for decomposition of volatile organic compounds(VOC) in air and water has attracted much attention. However, а photocatalytic efficiency ofsuch materials should be enhanced for their wide application. Energy-band structure ofeffective photocatalyst could provide transfer of valence electron to exited state and preventthe electron-hole recombination. The presence of strongly defected amorphous phase could beattributed to a large number of defects, which are a trap for charge carriers. Fujihara hasshown that amorphous phase of octahedron complexes TiO 68-charge from Ti 3+participates in transfer ofto O - [1]. This provides a decrease of electron-hole recombination.Unfortunately, the amorphous phase is very unstable and should be stabilized. The mostpromissing method of amorphous phase stabilization is distribution of TiO 2 over suitablesupport, for instance, SiO 2 aerogel [2].In the present work, the distribution and type of free charge carrier generated on the surface ofsamples was investigated. Two series of TiO 2 /SiO 2 and TiO 2 /Al 2 O 3 photocatalysts wereprepared by heterogeneous deposition [2]. TTIP (98 %), TEOS (99 %) and γ-Al 2 O 3 wereselected as precursors of titania, silica and aluminia, respectively. The content of activecomponent was varied from 3 to 15 % wt. Physical-chemical properties and structures of thecatalysts prepared were studied using XRD, FTIR and UV-Vis spectroscopy. The modelreactions of photochemical deposition of cationic Ag + and Pb 2+ were used for identification ofa character of the free charge carrier distribution on the photocatalyst surface according to [3].The activity of photocatalysts was investigated in photooxidation of methylene blue dye underthe static conditions.This work was supported by the grant of the Russian Federal purposeful program “Scientificand scientific-educational personnel of innovative Russia” (16.740.11.0604).References:[1] K. Fujihara, S. Izumi, T. Ohno, M. Matsumura, J. Photochem. Photobiol. A: Chem. 2000. V. 132.P. 99-104.[2] M. Fedotova, G.Voronova, E. Emel’yanova, N. Radishevskaya, O. Vodyankina, Rus. J. Phys.Chem. A. 2009. V. 83. No 8. P. 1371-1375.[3] A. Evstratov, K. Kish, A. Malygin et al., Rus. Chem. J. 2007. V. 51. No 6. P. 52-60.321