In order to clarify the wavelength-dependent effects produced by nitrogen and/or fluorine on the UV-vis photoactivity of NH4Fdoped TiO2, three series of doped TiO2 photocatalysts were investigated, prepared by sol-gel synthesis either employing HF as dopant source, or co-doped with boron and fluorine, or only with boron. Both the dopant amount and the calcination temperature (500 - 700 °C) varied within each series. The oxidative decomposition of both formic and acetic acid were employed as photoactivity test reactions. A detailed comparison between the photoefficiency in acetic acid decomposition as a function of the irradiation wavelength with the absorption spectra of doped materials demonstrated that fluorine, and not nitrogen, is responsible for the photoactivity increase in the UVA region observed with doped TiO2 calcined at high temperature.
Action spectra analysis of TiO2 singly doped or co-doped with fluorine and boron / M.V. Dozzi, B. Ohtani, E. Selli - In: 7th European Meeting on Solar Chemistry and Photocatalysis: Environmental Applications / [a cura di] A. Silva, C. Gomes Silva, J.L. Faria, R. Segundo, V.J.P. Vilar. - Porto (Portugal) : Sociedade Portuguesa de Química, 2012 Jun. - ISBN 978-989-97667-4-7. - pp. 709-711 (( Intervento presentato al 7. convegno European Meeting on Solar Chemistry and Photocatalysis: Environmental Applications tenutosi a Porto (Portugal) nel 2012.
Action spectra analysis of TiO2 singly doped or co-doped with fluorine and boron
M.V. DozziPrimo
;E. SelliUltimo
2012
Abstract
In order to clarify the wavelength-dependent effects produced by nitrogen and/or fluorine on the UV-vis photoactivity of NH4Fdoped TiO2, three series of doped TiO2 photocatalysts were investigated, prepared by sol-gel synthesis either employing HF as dopant source, or co-doped with boron and fluorine, or only with boron. Both the dopant amount and the calcination temperature (500 - 700 °C) varied within each series. The oxidative decomposition of both formic and acetic acid were employed as photoactivity test reactions. A detailed comparison between the photoefficiency in acetic acid decomposition as a function of the irradiation wavelength with the absorption spectra of doped materials demonstrated that fluorine, and not nitrogen, is responsible for the photoactivity increase in the UVA region observed with doped TiO2 calcined at high temperature.
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