微波直接合成與鑑定含金屬之三度空間SBA-16奈米孔洞材料

Direct Microwave Synthesis and Characterization of Three-Dimensional metallosilicate SBA-16 nanoporous materials

王宏丞(Hung-Cheng Wang)

指導教授 ： 鄭吉豐

中原大學/理學院/化學研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500507

摘要

本研究分兩部份以後討論、主要都是利用微波方法合成包金屬目標三次空間SBA-16奈美國孔洞材料。 第一部份為矽酸鈦立方排列中孔洞分子篩SBA-16材料。第二部份為矽酸鋁立方結構中孔洞分子篩SBA-16材料。此兩種材料藉由微波能快速、高效率達到均勻加熱的特性，來找出最佳合成的條件。
在微波直接合成Ti-SBA-16部份，經微波溫度80℃下反應60 min即可得到立方堆積結構的矽酸鈦分子篩，隨微波溫度的增加，矽酸鈦中孔洞分子篩的表面積、中孔體積及孔洞大小有增大的趨勢，但四配位鈦部份轉化為二氧化鈦聚合體。在Si/Ti比為10以上時，鈦都是以結構上四配位的型態出現，但Si/Ti比為5以下時，部份鈦形成二氧化鈦聚合體，並且經過100℃沸水中168小時後，矽酸鈦中孔洞分子篩還是保有良好的立方堆積結構，因此鈦金屬有助於水熱穩定性的效果。
而微波直接合成矽酸鋁分子篩的部份，因為在酸性下鋁易形成正三價離子型態，不容易進入立方結構中孔洞分子篩SBA-16的骨架內，所以將溶液的環境調到pH值為5微波溫度80℃的條件下來合成，約有60%以上的鋁在產物中，並且從NMR可測得，超過90%以上為四配位鋁的鍵結，其表面積為563.1 m2g-1，孔洞大小為4.77 nm，在經過100℃沸水中14天後，矽酸鋁分子篩的立方堆積結構還是保持完整，中孔的表面積及體積有增大的趨勢，因此鋁有增強分子篩水熱穩定性的效果。

關鍵字

微波 ； 奈米材料 ； 中孔洞分子篩 ； 金屬

並列摘要

Ti-substituted cubic SBA-16 materials have been successfully synthesized by using tetraethyl orthosilicate (TEOS) as the silica source, the titanium source of titanium(IV) chioride, and a triblock copolymer F127 as structure directing agents under microwave- irradiated condition within one hour. These materials were characterized by powder X-ray diffraction patterns (XRD), nitrogen adsorption, UV-vis diffuse reflectance, and HRTEM images. Synthesis parameters of radiation temperature, time, and titanium source and amount were systematically varied and affected the structure of Ti-SBA-16. Titanium coordination enviroment are sensitive to radiation temperature and titanium amount. The cubic Ti-SBA-16 structure were well-preserved even if materials were treated in boiling water for 168 hours. The highly hydrothermal stability could be illustrated by thicker wall and titanosilicate protection of mesoporous wall.
Al-substituted cubic SBA-16 materials have been also directly synthesized by microwave at 80 aC for 60 min in the pH of 5. About 60% of aluminum was contained in SBA-16 products and more than 90 % of Al is 4-coordinated and incorporated into the framework of SBA-16. The cubic Al-SBA-16 structure were well -preserved even if materials were treated in boiling water for 14 day. The highly hydrothermal stability could be illustrated by thicker wall and aluminosilicate protection of mesoporous wall. Three dimensional cubic titanosilicate and aluminosilicate with large cage could are expected to be useful as a selective oxidation catalyst for reactions involving large molecules.

並列關鍵字

microwave ； SBA ； mesoporous

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