Kang, Misook and Hong, Won-Jong (2006) The super-hydrophilicities of Bi-TiO2, V-TiO2, and Bi-V-TiO2 nano-sized particles and their benzene photodecompositions with H2O addition. Materials Letters, 60 (9-10). 1296 - 1305.
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Official URL: http://www.sciencedirect.com/science/article/B6TX9...
This study focused on the super-hydrophilicities of metal-TiO2 photocatalysts, including metals with three-oxidation and five-oxidation states, and their benzene photodecompositions with or without H2O addition. The nanometer-sized metal-TiO2s, including Bi3+, V5+, and Bi3+–V5+ ions, were prepared using a solvothermal method. The XRD result identified these to have pure anatase structures after solvothermal treatment at 200 °C for 10 h, without any treatment. The spherical particle sizes were distributed within the range of 10–50 nm after 500 °C calcinations, and the particle sizes decreased with an increase of the Bi component, while it increased with the V component compared with that of pure TiO2. The XPS result showed that the peaks for O1s (Ti–O) shifted to the larger binding energy in Bi–TiO2; on the other hand, it shifted to the smaller binding energy in V–TiO2. In particular, the Ti–OH peak, which means to hydrophilicity, decreased with an increase of the Bi component; it increased, however, with the V component. The contact angle expressed about 3° on the Bi–TiO2 nano-sized film (200-nm thickness) after irradiation for 2 h; otherwise, it approached 0° on the V–TiO2 nano-sized film after 30 min. In particular, the decreased angle was continued under dark condition on the Bi–V–TiO2 nano-sized film. The benzene photodecomposition in the batch system increased in the order of Bi (3.3)–V (6.7)–TiO2 > V–TiO2 > pure TiO2 > Bi–TiO2, and the maximum benzene conversion was 35% after 60 min. The conversion remarkably increased, however, in almost all catalysts with H2O addition during the benzene photo-decomposed reaction, and in particular, the conversion reached up to 80% after 180 min in Bi–V–TiO2. In the continuous system for Bi–V–TiO2 with H2O addition, the photodecomposition rate of 50% was maintained for 168 h, without catalytic deactivation. After photoreaction, there were minimal deposited cokes in the photocatalyst in both reaction conditions, with and without H2O addition. The deposited amounts were smaller, however, in the reaction with H2O addition. This result is a proof that photocatalytic deactivation can be retarded by an H2O supplement during VOC decomposition.
|Subjects:||Material Science > Nanostructured materials|
|Deposited On:||06 Feb 2010 11:42|
|Last Modified:||06 Feb 2010 11:42|
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