- 學位論文
孔洞材料及其在催化和吸附的應用
Porous Materials and Their Applications in Catalysis and Adsorption
摘要
在新穎材料中，由於孔洞奈米粒子具有好的結構排列、高比表面積及均勻的孔徑大小，因此經常作為高效能催化劑使用。許多研究指出，合成具有孔洞結構的金屬氧化物粒子可提升在材料的光學特性及催化反應中的轉換效率。本論文著重於中孔洞氧化鈦奈米粒子/中孔洞氧化鋯奈米粒子(MTNs/MZrNs)及去鋁化beta沸石的應用層面，論文中共有三個部分含括所述。 於論文第一部分，首先合成出金奈米粒子嵌入中孔洞氧化鈦奈米粒子(Au@MTNs)，後將Au@MTNs利用低溫電泳沉積（EPD）的方式，透過高壓後處理在導電塑膠基材上形成薄膜。由於中孔洞氧化鈦奈米粒子(Au@MTNs)的薄膜內含有金奈米粒子，其具有表面電漿共振效應，因此具有良好的光子捕捉能力。當Au@MTNs內金奈米粒子的濃度為0.8 wt%時，於100 mW cm-2的模擬日光照射強度下，可達到最大的能量轉換效率為5.62%，相較於純粹用氧化鈦粒子 (TiO2) 所製成的光電極薄膜 (4.93%) 在最大的能量轉換效率上有14%的提升，此能量轉換效率的提升歸因於金奈米粒子電漿場的光捕獲效應。 於論文第二部分之目的為有系統地分析5-氟尿嘧啶（5FU）/雙硫崙（DSF）和不同種類沸石 (zeolite) 之間的吸附關係。在實驗當中，5-氟尿嘧啶與雙硫崙分別視為一親水性與疏水性客體分子探討親疏水性分子與沸石(MFI、BEA及 FAU) 之間的吸附關係。為了深入探討5-氟尿嘧啶/雙硫崙的恆溫吸附曲線，利用三個理論吸附模型比對實驗數據分析計算理論係數及平衡常數，這些參數可用來解釋5-氟尿嘧啶/雙硫崙在沸石中的吸附行為。影響5-氟尿嘧啶/雙硫崙在沸石的吸附量可歸咎於螯合作用(只有5-氟尿嘧啶)、氫鍵、凡德瓦爾相互作用和沸石孔徑；此外，去鋁化Beta沸石由於結構缺陷可提升5-氟尿嘧啶/雙硫崙吸附量，因此設計將雙硫崙的疏水性質當作孔洞蓋子以減緩5-氟尿嘧啶的釋放。 第三部分中，中孔洞氧化鋯奈米粒子（MZrNs）和錫中孔洞氧化鋯奈米粒子 (Sn_MZrNs) 被應用於催化丙酮醛至乳酸甲酯的反應。無晶像的中孔洞氧化鋯奈米粒子於本篇文章中首次報導具有高度催化活性；此外，錫中孔洞氧化鋯奈米粒子於無晶型結構上具有大的比表面積及在水熱處理後有兩種混合晶體型態(tetragonal/monoclinic)。將錫合成於介孔氧化鋯奈米粒子作為催化劑具有在Meerwein–Ponndorf–Verley reductions/Oppenauer oxidations增強路易斯酸的特性且達到90%乳酸甲酯轉換率，在反應中的高轉換速率及效率歸因於中孔洞氧化鋯奈米粒子的高表面積和四方晶體結構。
並列摘要
Porous nanoparticles are highly effective as catalysts because of a well-oriented structure, large surface area and uniform pore size. Metal oxides with a porous structure are widely used to augment optical characteristics and conversion efficiency. This dissertation focusses on applications of mesoporous titania/zirconia nanoparticles (MTNs/MZrNs) and dealuminated beta zeolite (deAl BEA). A thin film of gold nanoparticles inlaid with mesoporous titania nanoparticles (Au@MTNs) was fabricated on a conductive plastic substrate using low-temperature electrophoretic deposition (EPD) followed by a compression post-treatment. The resulting Au@MTNs electrode exhibits excellent light trapping performance thanks to the formation of surface plasmons on the Au nanoparticles (NPs). The use of 0.8 wt% Au NPs in the Au@MTNs photoanode resulted in power conversion efficiency (η) of 5.62% under illumination of 100 mW cm–2. This represents a 14% improvement in conversion efficiency, compared to the DSSC fabricated using pure a titanium dioxide (TiO2) photoanode (4.93%), due to the plasmonic light trapping provided by the Au NPs. Our aim was to study the relationship between 5-fluorouracil (5FU)/disulfiram (DSF) and various framework zeolites. The 5FU and DSF respectively deemed a hydrophilic and a hydrophobic guest molecule to observe the adsorption on MFI, BEA and FAU zeolites. Three isotherm models were fitted and discussed in 5FU loaded zeolite isotherm. The 5FU/DSF loading amount can be attributed to the chelating effect, hydrogen bond, Van Deer Waal interaction, and size of pores in the zeolite. The deAl BEA reached a high 5FU loading as FAU zeolite because of the structure defects. The DSF furthermore served as a cap to prolong the 5FU release. MZrNs and Sn_MZrNs were synthesized and applied in pyruvaldehyde to perform a methyl lactate reaction. Amorphous MZrNs were first reported in this study to demonstrate high catalytic activity. In addition, Sn_MZrNs exhibit a large surface area in amorphous particles and a mixing tetragonal/monoclinic crystallite after hydrothermal treatment. Tin synthesized inside the MZrNs provided strong Lewis acid sites, which strengthened the Meerwein–Ponndorf–Verley reductions/Oppenauer oxidations and achieved 90% methyl lactate conversion. The high conversion rate and efficiency are attributed to a high surface area and tetragonal structure of Sn_MZrNs.