The Development of Multi-Component Photocatalysts and their Applications to Decomposition of Organic Contaminants
| Autor: | Hong-chang Chen, 陳宏昌 |
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| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 In this study, we used sol-gel method with electrospinning technology to prepare Ag/TiO2/ZnO composite ultrafine fibers as a photocatalyst, which can decompose methylene blue by visible light. The characteristics of various Ag/TiO2/ZnO composite ultrafine fibers with various sinter temperature were measured using Scanning Electron Microscope(SEM), Transmission Electron Microscope(TEM), X-Ray Diffraction(XRD), Energy Dispersive Spectrometer(EDS), low temperature N2 adsorption(BET), and UV / VIS absorption spectroscopy (UV-Visible) for understanding ultrafine fibers’ morphology and distribution, crystalline phase, elemental composition, specific surface area, visible light absorption and energy band gap. Finally, the photodegradation efficiencies of the prepared samples were evaluated by photolysis solid - liquid phase of methylene blue dye under the condition of visible light. The SEM surface morphology observed that Ag/TiO2/ZnO as fiber type had a smaller fiber diameter than TiO2. TEM observation concluded that Ag/TiO2/ZnO fiber surface had distribution of Ag nanoparticles. EDS shows that various Ag/TiO2 molar ratio of Ag/TiO2/ZnO proportion had similar results to that of expectation. The XRD analysis showed that the introduction of silver inhibited the growth of anatase type with small size. When sinter temperature increased, the particle size became large and a significant trend of crystalline phase generated. UV-Visible results show that Ag/TiO2/ZnO fibers had ability of absorption in visible light region and reduce the energy gap. BET analysis showed that the introduction of an appropriate amount of silver particles increased the surface area, but the excess silver particles reduced the specific surface area. Finally, this study conducted a series of degradation experiments of methylene blue using Ag/TiO2/ZnO ultra-fine fibers under visible light. The results show when the sinter temperature at 450oC, 2.0% Ag/TiO2/ZnO ultra-fine fibers has the best visible light degradation efficiency. It indicated that three synergistic effect heterostructure Ag/TiO2/ZnO ultra-fine fibers have good catalytic effect under visible light. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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