具核-殼結構之金屬奈米粒子合成及其特性分析
Other Title
Synthesis and Characterization of Metal Nanoparticles with Core-Shell Structure
Date Issued
2004
Date
2004
DOI
zh-TW
Abstract
Nano-material refers to material with dimensions between 1 and 100 nm. This kind of material shows special properties different from bulk material because of the small size, high surface area, and quantum size effect. Nano-materials attract attentions in the field of optical absorption, optical sensitivity, and catalysis. Alignment of atoms is not long range ordered, and the continuous band structure observed in bulk materials becomes discontinuous, being similar to molecular orbital for nano materials. High density interface structure leads to changes in properties of mechanics, magnetism, dielectrics, superconductivity, optics, and thermodynamics. In addition, novel core/shell structured nano particles synthesized by using different materials in core and shell exhibit interesting properties. Core/shell structured nano particles show high potential for studying in fundamental theory and academic research, especially in colloid science and interface science.
In this work, chemical method is used for metal reduction to obtain metal nano particles. Difference in the rate of reduction for different metals is considered to fabricate core/shell structured nano particles. This study is divided into two parts. One is Au/Pt core/shell structured nano particles, and the other is Au/Ag bimetallic nano particles containing core/shell structure and alloy. The particle size and morphology are studied by high resolution transmission electron microscopy (HRTEM). The chemical composition is investigated by ultraviolet/visible spectrophotometer (UV/vis). X-ray absorption spectroscopy by using synchrotron radiation is used for studying fine structure. The target of this work is to change the core/shell properties of material, structure, optics, and surface. The results of this work are useful in the field of single electron transistor, conductive film, and catalyst.
Subjects
X光吸收光譜
雙金屬
核-殼
core-shell
bimetallic
EXAFS
Type
thesis