合成二氧化矽/銀核殼結構及其表面電漿子共振引發之光催化效應研究

The Plasmonic Induced Photocatalyst of Silica/Silver Core-Shell Structure

梁藝礬(Yi-Fan Liang)

指導教授 ： 施漢章 ； 葉均蔚

國立清華大學/工學院/材料科學工程學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00337

摘要

本實驗成功利用無電電鍍法(electroless plating)，以氯化亞錫作為表面修飾劑，藉由在液相中之氧化還原反應成功合成單一粒徑且均勻性高之二氧化矽/銀核殼結構，並使用氨銀溶液作為前驅物、葡萄糖作為還原劑進一步地控制銀顆粒之大小。
在形貌分析上，利用SEM、TEM進行觀察其二氧化矽粒徑大小、表面形貌、銀顆粒粒徑之批覆情形，並以軟體(SigmaScan®Pro )計算其粒徑分佈。元素分析方面則藉由XRD確認銀之主要繞射晶面，並以HRTEM觀察單一銀顆粒上之晶面間距；最後透過XPS觀察銀、錫離子與二氧化矽間因鍵結所造成之化學位移(chemical shift)。
不同於單一成分之金屬顆粒，不同形貌的二氧化矽/銀核殼形結構，呈現多樣、可調控之光學特性，在本實驗中，隨著銀顆粒由10奈米成長至50奈米，其表面電漿共振之可見光-紫外光吸收光譜有兩個明顯趨勢: (1)特徵吸收峰值產生紅移現象;(2)其峰形明顯加寬。
有別於二氧化鈦之光催化反應需利用紫外光，本實驗藉由調控二氧化矽/銀核殼結構之樣貌來改變其SPR吸收波段，高效率地轉換可見光能量於有機分子之分解反應上，不僅能有效利用天然之太陽能源，也解決了隨工業、科技發展所帶來之環境汙染問題，可謂是一舉數得。

關鍵字

二氧化矽 ； 銀 ； 核殼結構 ； 光催化

並列摘要

In this study, silica/silver core-shell nano-spheres with uniform diameter and morphology were successfully synthesized by a facile electroless plating method within a mild condition. With the help of glucose, the particle size of silver nanoparticles (AgNPs) deposited on silica spheres was well controlled in the range from 10 to 50 nm.
The morphology of the SiO2/Ag was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while the lattice analysis were performed by X-ray diffraction (XRD) and high-resoluton TEM (HR-TEM). Furthermore, the binding energy and chemical shift were examined using X-ray photoelectron spectroscopy (XPS).
In the optical properties test, we found that when the diameter of AgNPs increased form10 to 50 nm, the surface plasmon resonance (SPR) absorption band shifted toward infra-red region and became broader gradually.
This result is very promising because the traditional TiO2 without doping other elements has to absorb UV-light to trigger the photocatalystic reaction. With the using of SiO2/Ag composite, we may efficiently change the solar energy to decompose the organic pollutants. It is not only a cost-effective route but also an energy-saving way to our environment.

並列關鍵字

silica ； silver ； core shell ； photocatalyst

參考文獻

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