奈米多孔材料及薄膜結構對於中高溫CO2吸附與轉化合成之開發研究

Abstract

本研究在第一年首先將針對Ca-Al-CO3 層狀水滑石(Layered Double Hydroxides, LDH)結構，以化學合成法來進行奈米粉體的合成的研究，並進一步探討CaO/SBA-15 多孔材料研製，改變其化學組成、合成溫度、燒結溫度、不同比例的結構，來分析其對 二氧化碳的吸附特性與機制，以大幅提高其二氧化碳氣體捕捉與分離的效益，而應用於 後續的流動化床的探討及製備。 由於LDH 無機材料具有熱穩定性、抗化學性以及機械特性，本研究在第二年將利用 電泳法及溶膠-凝膠法(sol-gel)製程在多孔的陶瓷基板如α-Al2O3 管狀基板，來製備LDH 奈米孔隙薄膜。初步的材料結構特性將以BET 進行測試比表面積與孔隙度，並以SEM、 TEM、XRD、FTIR 進行表面形貌與顆粒結晶性分析鑑定，再利用TGA 輔助初步的二氧 化碳吸附分析，並測試此多孔基板所鍍的LDH 奈米結構的無機薄膜層對於CO2 的吸附 及氣體分離的效果，探討高溫條件下捕碳劑於反應床之滯留時間、除碳量、突破曲線等 基本特性，以達到最佳的中高溫吸附與二氧化碳分離氣體的條件。 第三年將進而利用溶膠-凝膠法及共沉方式來研製發展Cu/ZnO或Cu/ZnO/Al2O3 奈 米觸媒材料，以大幅提升CO2 的固定化及DME/DM 等化合物轉化及合成效率，以應用 在氣體分離、減碳，與促進能源燃料使用的效率等，以達成節能環保的目標。因此本研 究整體是以奈米微粒研製技術作為基礎，目的在開發高性能低成本捕碳材料與CO2 轉化 之化學觸媒，除探討其中的學理變化外，並與研究機構發展目標做實質結合，期能將研 究變成實際可行之成果並應用於未來的碳管理技術。

Nanoparticles of Ca-Al-CO3 layered double hydroxides (LDHs) with different Ca/Al ratio was synthesized by sol-gel and coprecipitation in this study. In addition, mesoporous CaO/SBA-15 was also synthesized as a function of chemical composition, reaction temperature and calcinations temperature. Both characterization and thermal evolution was investigated using X-ray diffraction (XRD) and FT-IR spectroscopy. The crystallinity of LDH was investigated by high-resolution transmission electron microscope (HRTEM). Nitrogen adsorption isotherm (BET) will be applied to study the surface area and pore volume. Thermogravimetric analysis (TGA) is also used to analyze CO2 sorption from 400 to 800oC to investigate its mechanism of CO2 sorption. Different proportion of CO2/N2 with different feeding rate was also used to test the CO2 adsorption capacity of Ca-Al-CO3, it still display a relative high sensitivity of CO2 adsorption. The LDHs unique properties for membrane can be particularly for application in high temperature CO2 separation and hydrogen production. Electrophoretic deposition (EPD) was utilized as a new method for the preparation of hydrotalcite (HT) thin films. The films were deposited on macroporous alumina substrates and stainless steel substrates. The LDH films show promise for applications as membranes and sorbant for N2, H2 and CO2. In the third year, Carbon Dioxide Fixation into Chemicals (DME, Methyl Formate) By Surface Coupling Over Pd/Cu/ZnO based NanoCatalyst will be further investigated.