利用不同還原方法合成金奈米粒子於中孔洞二氧化鈦之複合材料

Abstract

此論文著重在探討將金奈米粒子分別合成於中孔洞二氧化鈦奈米粒子(MTNs)與薄膜(MTTF)之孔洞結構中的方法與結果。 中孔洞二氧化鈦材料一直受到廣泛的研究，其原因乃受惠於材料本身的獨特性，如高比表面積、高孔洞體積以及可調整的孔洞大小等。最重要的是，二氧化鈦是種常被使用在光電元件與光電技術上的半導體材料。近年來的研究發現，中孔洞二氧化鈦材料摻雜貴重金屬，如金、銀、鉑等，能夠有效提升以二氧化鈦為主體的光電元件效率，故近幾年來中孔洞二氧化鈦材料摻雜不同貴重金屬的研究開始被受到關注。 在這次的研究裡，我們嘗試使用四種不同還原方法，如熱處理、光處理、液相處理以及氣相處理，將金奈米粒子合成於MTNs與MTTF之孔洞結構中。合成好之金奈米粒子於中孔洞二氧化鈦複合材料(Au@MTNs and Au@MTTF)則利用紫外光/可見光光譜儀(UV-VIS)、X光繞射儀(XRD)、掃描式電子顯微鏡(SEM)以及穿透式電子顯微鏡(TEM)，進行特性分析。 我們更進一步發現到金奈米粒子在MTNs與MTTF裡的成長方式。在Au@MTNs的實驗中，我們僅能利用熱還原法將金奈米粒子還原在MTNs的孔洞結構裡，且金奈米粒子的粒徑大小約為6.7 nm左右。在Au@MTTF的實驗中，我們則可以利用光還原法分別將分散性良好的金奈米粒子還原在MTTF的薄膜表面以及薄膜內部的孔洞結構中，其金奈米粒子的粒徑大小分別為17.8 nm以及4.1 nm。

This study focus on the synthesis of gold-embeded mesoporous titania nanoparticles and thin films (MTNs and MTTF, respectively). Mesoporous titania materials have been extensively studied because of their special characters, for example, high surface area, pore volume, and tunable pore size. Most importantly, titania is a semiconductor so has been widely used in photoelectronic devices and technologies. Recently, mesoporous titania materials doped with noble metals such as gold, silver and platinum have attracted considerable attention because the noble metals can enhance the efficiency of the titania-based devices. In this research, we attempted to use four different reduction methods (i.e., thermal treatment, photo treatment, liquid treatment and vapor treatment) to synthesize gold nanoparticles into MTNs and MTTF. The synthesized Au@MTNs and Au@MTTF were characterized with UV-Vis spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We further systematically investigated the formation mechanism of gold nanoparticles in MTNs and MTTF. In the case of Au@MTNs, gold nanoparticles could be reduced in MTNs only by thermal treatment, and the size of the gold nanoparticles is around 6.7 nm. In the case of Au@MTTF, well-dispersed gold nanopaticles could be obtained on and inside (the size is 17.8 and 4.1 nm, respectively) the MTTF by photo treatment.