具核-殼結構之金屬奈米粒子合成及其特性分析

Synthesis and Characterization of Metal Nanoparticles with Core-Shell Structure

陳浩銘(Hau-Ming Chen)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01039

摘要

奈米材料乃指其尺寸介於1∼100 nm而言。因其尺寸小、比表面積大及量子尺寸效應，使之具有一般塊材所不具備之特殊性能，即於光吸收、敏感、催化及其它弁鉒S性等方面展現出引人注目之應用前景。奈米晶粒中原子排列已非長程有序結構，一般塊材之連續能帶分裂成類似分子軌域之不連續能階，高濃度晶界及晶界原子之特殊結構導致材料之力學性能、磁性、介電性、超導性、光學乃至於熱力學性能之改變。此外另一新穎結構之奈米粒子-核-殼(core-shell)結構，藉由改變內核與外殼之材料，而展現釵h特殊之性質，此結構之奈米粒子於基本理論及學術上具有高度之研究價值，尤其於膠體科學(colloid science)以及界面科學(interface science)上，為一個針對膠體交互作用、穩定與分散現象絕佳之研究舞台。
本研究乃利用化學法還原金屬鹽水溶液，而獲得金屬奈米粒子，且利用相異金屬鹽還原速率差異而獲得具核-殼結構之金屬奈米粒子，本研究分成兩大系統，一為金與鉑核-殼結構之奈米粒子，另一系統為金與銀之奈米粒子，於此系統中分別合成具核-殼結構與合金結構之金屬奈米粒子，兩系統均以高解析穿透式電子顯微鏡分析其粒徑與形貌，以紫外/可見光光譜儀分析其組成，亦以同步輻射之X光吸收光譜分析其細微結構，藉以獲得吸收原子周圍配位數與鍵長之關係。本研究發展核-殼結構之奈米粒子，重點在於改變內核與外殼之材料、結構、光學或表面特性，預期將可應用於單電子電晶體、導電膜與觸媒等領域。

關鍵字

X光吸收光譜 ； 雙金屬 ； 核-殼

並列摘要

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.

並列關鍵字

core-shell ； bimetallic ； EXAFS

參考文獻

3. 張仕欣與王崇人, 化學 56, 209 (1998).

4. D. R. Lide, CRC Handbook of Chemistry and Physics, 74th ed. (CRC,

696 (1997).

281, 2013 (1998).

11. C. Ducamp-Sanguesa, J. Solid State. Chem. 100, 272 (1992).