Synthesis of Au@TiO2 and Ag@TiO2 Core/Shell Nanocomposite
| Autor: | Chang-Hao Huang, 黃健豪 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 This study investigated the phase transfer of aqueous Au nanoparticles and Ag nanoparticles into the organic solution by adding different surfactant and ionic liquid and thereafter the preparation of Au@TiO2 and Ag@TiO2 nanocomposite materials.To prepare Au@TiO2 and Ag@TiO2 nanoparticles, metal nanoparticles have to be firstly prepared. Metal nanoparticles are usually produced in aqueous solution, due to the water-soluble nature of metal salt. In addition, synthesis of different sized and shaped nanoparticles in aqueous solutions is easier than that of in organic solutions. However, some applications of metal nanoparticles have to be performed in organic phase. For example, TiO2 coating of metal nanoparticle by hydrolysis-condensation of titanium dioxide，s precursor in water is very fast. Hence, the size and thickness of the Core-Shell composition are very difficult to control in water-based solution, as in contrast with that of in organic solution. This research examined the effect of organic solvent, modifier, precursor and concentration of ionic liquid on the formation of core-shell material. The results indicate that : (1) Ionic liquid can be employed to transfer the nanoparticles from aqueous phase into organic phase and the efficiency of phase transfer is proportion to the concentration of ionic liquid. The data implies that the ionic liquid behaves as an ion-pair reagent in the process of phase transfer. (2) Organic solvent and modifier are definitely required to form a stable core-shell structure. (3) The size of Au@TiO2 and Ag@TiO2 nanocomposite is proportion to the concentration of ionic liquid in organic solution. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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