| Summary: | 碩士 === 國立臺灣科技大學 === 材料科學與工程系 === 104 === In this study, Ag@TiO2 core-shell nanoparticles (NPs) by two-step method. Ag nanoparticles was prepared by thermal assisted photoreduction method (TAP), and then covered by TiO2 NPs which were obtained by chemical reduction method. The morphology, crystallinity, and electronic structure of NPs were characterized by using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Raman and X-ray absorption spectroscopy (XAS). Our results first showed that TiO2 NPs could be synthesized by chemical reduction method. However, residual precursor was observed as the concentration of precursor reached 4mM. Second, Ag@TiO2 core-shell NPs were synthesized successfully by two step reduction method. Shell thickness can be controlled easily by adjusting the concentration of precursor. It is also demonstrated that defects, including oxygen vacancy and Ti3+, were introduced after the formation of core shell structure. At last, enhanced room temperature ferromagnetism was observed of Ag@TiO2 core-shell NPs.
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