Study on the degradation of methylene blue by V-TiO2 under visible light
| Autor: | Chen-Ling Hu, 胡正苓 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 The object of this study is the synthesis of visible-light responsed TiO2 photocatalysts. The V-doped TiO2 was synthesized by two different sol-gel methods. The prepared photocatalysts were characterized by Field emission scanning electron microscope (FE-SEM), Electron spectroscopy for chemical analysis system (ESCA), Brunauer emmett teller (BET), X-ray powder diffractometer (XRD) and Point of zero charge (pHzpc). The photocatalytic activity was evaluated by the degradation of methylene blue under visible light. From the external analysis of SEM, ESCA and XRD, the results showed that the particle size of TiO2 was about 30 nm and mainly Anatase structure, but the contents of the Rutile phase increased with the increase of the amount of doped Vanadium on TiO2. The valence number of V-TiO2 photocatalyst were not altered and Vanadium in the TiO2 structure was in the status of V3+, V4+ and V5+. According to the BET, doped Vanaduium on TiO2 would decrease the surface area due to decrease of porosity. The pHzpc of V-TiO2 phtotcatalyst were lower than pure TiO2. Compare with Janssen TiO2, the V-TiO2 have better response of visible light. In visible light/V-TiO2 system, at pH 2 and pH 7 have better discoloration and mineralization. The photocatalystic reaction mechanism was investigated by visible light/V-TiO2 system. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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