Photodecomposition of 2,4-dinitroaniline on Li/TiO2 and Rb/TiO2 nanocrystallite sol-gel derived catalysts

Sol-gel titania was prepared and doped with lithium and rubidium. In samples annealed at 400 degreesC specific surface areas around 100 m(2)/g were obtained. By increasing the thermal treatment (600 degreesC) the solids notably diminishes their specific surface area (lower than 27 m(2)/g), The band gap of the samples was determined by UV-VIS absorption spectroscopy. A decrease of the E-g was observed in titania and doped titania while the temperature was increased. The XRD spectra of the samples showed that at 600 degreesC the main phase in TiO2 and Rb/TiO2 was anatase, while in Li/TiO2 the main phase was rutile. Activities for the 2,4-dinitroaniline photodecomposition suggest an incorporation of lithium in the titania structure, since it is the catalyst showing the lowest activity. (C) 2001 Elsevier Science B.V. All rights reserved.