藉由光催化法於多氧金屬酸化合物與中孔洞二氧化矽的混合薄膜中製備金奈米粒子

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Please use this identifier to cite or link to this item: http://140.128.103.80:8080/handle/310901/11007

Title:	藉由光催化法於多氧金屬酸化合物與中孔洞二氧化矽的混合薄膜中製備金奈米粒子
Other Titles:	Synthesis of Au nanoparticles in the Polyoxometalate/Mesoporous Silica Hybrid Films by Photocatalytic Method
Authors:	黃教程 Huang , Chiao-Cheng
Contributors:	賴英煌 Lai, Ying-Huang 東海大學化學系
Keywords:	多氧金屬酸化合物;中孔洞材料 Mesoporous
Date:	2011
Issue Date:	2011-10-12T07:38:21Z (UTC)
Abstract:	中孔洞材料具有高表面積、奈米尺寸的孔徑與高穩定性等優點，因此眾多研究著重於表面的修飾，以提高材料之應用價值。本論文主要目標為合成具有多功能性的混合薄膜，其方法為製備中孔洞二氧化矽材料過程中，添加多氧金屬酸進行薄膜改質，使多氧金屬酸取代界面活性劑與二氧化矽間的鹵素陰離子，形成具有光催化活性之混合薄膜，再利用此混合薄膜照光還原特性，使不同濃度金離子於孔洞材料中還原成金原子，進而堆積成金奈米粒子。利用掠角入射小角度散射 ( Grazing Incidence Small Angle X-ray Scattering、 GISAXS ) 探討不同溫度、矽源與多氧金屬酸濃度條件下，觀察混合薄膜成長動力學及相轉變過程，由實驗結果顯示速率常數 ( k )為 1.80 × 10－4 ? 1.15 × 10－3 s－1，反應級數約1.30 至 1.45之間，最後結構為二維六方相，相轉變路徑為等同性相 ( Isotropic phase ) 轉變為二維六方相 ( 2D-Hexagonal phase )。另以 X 光繞射光譜儀、傅立葉轉換紅外線光譜儀、穿透式電子顯微鏡、熱重分析儀與紫外可見光吸收光譜儀等儀器進行薄膜之特性鑑定，結果顯示此混合薄膜的孔徑約為 1.8 nm，在不同金離子濃度條件進行光催化還原，可觀察到孔洞中金粒子之粒徑皆約為 1.7 nm，證實多氧金屬酸二氧化矽混合薄膜具有光催化還原特性。 Most of the previous studies of mesoporous silica materials on surface modification have attracted much attention, due to its intrinsic properties, such as high surface areas, regular channels of uniform pore sizes and high stability. To synthesize a novel functional mesoporous hybrid material, modification of the mesoporous silica by adding polyoxometalates (POMs) in the sol-gel procedure was taken. The halide anions of surfactants are exchanged for POM anions, forming photocatalytic POM/silica hybrid films. Furthermore, the gold nanoparticles (NPs) embedded hybrid films were synthesized by utilizing the reduction property of POMs with variable gold precursor concentration. In situ grazing incidence small angle X-ray scattering technique was used to study kinetics and growth mechanism of the hybrid films with variable temperature, silica precursor and POM concentration. The growth rate constants (k) are between 1.80×10－4 to 1.15×10－3 s－1, and the reaction orders are between 1.30 to 1.45. In addition, the result indicates the mesostructure transformation from isotropic phase to 2D-hexagonal phase. The properties of hybrid films were characterized by X-ray diffractometer, Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, ultraviolet–visible spectroscopy. The results show that the pore size is about 2.3 nm, and containing reduced gold NPs with size about 1.7 nm, indicating the photocatalytic property of these POM/silica hybrid films.
Appears in Collections:	[化學系所] 碩博士論文

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