I. 中孔洞二氧化矽薄膜的低溫模板分子移除法與結構性質研究. II. 鈀金屬薄膜與奈米粒子的製備及儲氫性質研究

I. Structural Characterization and Moderate Template Removal of the Mesoporous Silica Films. II. Synthesis and Characterization of Pd Metal Membrane and Nanoparticles

許坤章(Kun-Chang Hsu)

指導教授 ： 趙桂蓉

國立清華大學/理學院/化學系/博士(2009年)

摘要

本論文分為兩個部分，第一部份的內容中，我們以中性的界面活性劑Brij56及三區塊共聚高分子P123作為模板分子，製備超薄(厚度~ 200 nm)且具有規則排列結構的兩種中孔洞二氧化矽薄膜，並藉由低溫的超臨界二氧化碳萃取法(SCF-CO2, at 60 oC)或紫外光-臭氧照光法(UV-O3, 25 oC)來移除薄膜中的有機模板分子，以降低一般傳統高溫鍛燒(400 ~600 oC)方式，造成的薄膜結構收縮、破壞及基材耐熱性不佳等問題。實驗結果發現，經超臨界二氧化碳萃取法處理後的薄膜，具有較佳的結構規則度;而以紫外光-臭氧照光處理後的薄膜，則具有較高的薄膜孔隙度及較低的光學折射率(n = 1.32)。
第二部份的內容中，首先我們分別以界面活性劑穩定分散及中孔洞二氧化矽為支撐材(Pd/CTAB/M41 & M48)製備Pd金屬奈米粒子，並藉由XRD及TEM的量測，探討Pd金屬奈米粒子的粒徑熱穩定性。隨後，比較不同粒徑大小的Pd金屬奈米粒子(3.0 nm Pd/CTAB/M41, 5.0 nm Pd/CTAB/M48及11 & 22 nm Pd/CTAB)與Pd金屬薄膜(10 μm)的氫氣吸附性質。在此部分的鑑定分析中，我們以同步輻射作為光源進行in-suit XRD的量測，用來觀察不同粒徑大小的Pd奈米金屬粒子，在氫氣吸附/脫附過程所造成的晶格膨潤與氫氣吸附量估算值的影響，及其儲氫能力及氫氣儲存/釋放的操作溫度影響。另外，再以in-suit XAS的量測來觀察不同粒徑大小的Pd金屬粒子，吸附氫氣後所產生的Pd-Pd鍵長改變與氫氣吸附性質影響。

關鍵字

中孔洞二氧化矽薄膜 ； 模板分子移除法 ； X光平面反射率 ； 鈀奈米金屬粒子 ； 儲氫材料

並列摘要

The first section of this thesis is preparation of supported Brij56- or P123-SiO2 composite mesoporous silica thin films with thickness ~ 200 nm, which were dip-coated on Si-wafer, glass or Au/Cr/Si substrates. The template of mesoporous silica films were removed by supercritical fluid extraction (MeOH/SCF-CO2) at 60 oC, UV-O3 at 25 oC or thermal calcination at 400-500 oC. The SCF-CO2 modified with MeOH has been employed to remove template almost completely from Brij-56 and P123-SiO2 composite films on Si-wafer. SCF results the mesoporous silica film of higher degree of ordering and larger size of mesoporous with single mesophase than calcination. Furthermore, the supported P123-SiO2 composite films of high porosity with large surface area and pore volume, low average density and thickness were produced through UV-O3 treatment as characterized by X-ray reflectivity (XRR) and Kr adsorption, and with low refractive index of 1.32.
In the second section, we report the preparation of surfactant-stabilized (22.0, 14.6 and 11.6 nm Pd/CTAB) and surfactant/mesoporous silica composites (5.0 Pd/CTAB/M48 and 3.5 nm Pd/CTAB/M41) Pd nanoparticles by using colloid and one-pot synthesis method. After that, we study the thermal-stability of Pd nanoparticles by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis. In addition, the hydrogen adsorption/desorption properties of Pd nanoparticles and membrane were discussed by using in-suit XRD and X-ray absorption spectroscopy (XAS) during the hydrogen unloading or loading condition.

並列關鍵字

Mesoporous silica thin film ； template removal ； XRR ； Pd nanoparticles ； Hydrogen storage

參考文獻

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