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標題: | 鈀奈米顆粒擔載於石墨型氮化碳應用於糠醇的催化轉移氫化反應 Catalytic Transfer Hydrogenation of Furfuryl Alcohol over Palladium Nanoparticles Supported on Modified Graphitic Carbon Nitride |
作者: | Yan-Jhu Chou 周彥築 |
指導教授: | 游文岳(Wen-Yueh Yu) |
關鍵字: | 石墨型氮化碳,催化轉移氫化,表面鹼基,載體至金屬的電子傳遞,金屬分散度, graphitic carbon nitride,catalytic transfer hydrogenation,basic site,charge transfer,metal dispersion, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 催化轉移氫化(catalytic transfer hydrogenation, CTH)為一使用液態有機分子作為氫源(hydrogen donor)的氫化方法。相較傳統氫化方法多藉由高溫高壓氫氣作為氫源,催化轉移氫化的操作方便安全、實驗裝置便宜、且反應狀態溫和,因此對於生物質衍生物的選擇性氫化較為有利。 本論文以熱縮合方法將前驅物雙氰胺(dicyandiamide)製得塊狀的石墨型氮化碳(bulk g-C3N4, b-CN),接著利用熱剝蝕法將其剝蝕為奈米片狀結構(nanosheet g-C3N4, ns-CN),最後以沉積沉澱法將鈀奈米顆粒載負於兩種不同載體上製得Pd/b-CN和Pd/ns-CN。由觸媒的物理化學性質鑑定結果可得知,樣品皆具有石墨型氮化碳結構,剝蝕後片狀結構堆積減少與比表面積增加(18→51 m2 g-1),顯示了成功將b-CN熱剝蝕至ns-CN。氫氣化學吸附測得Pd/ns-CN擁有較高的鈀金屬分散度。光激發螢光頻譜在Pd載負後螢光強度下降,顯示b-CN和ns-CN兩載體皆有電子傳遞至鈀金屬的現象。本研究以生物質衍生物-糠醇(furfuryl alcohol)的催化轉移氫化生成四氫糠醇(tetrahydrofurfuryl alcohol)作為測試。活性測試結果顯示,Pd/ns-CN具有較高的催化活性。其較佳的催化活性可歸因於Pd/ns-CN具有較高的金屬分散度、較多的表面鹼性位點,及較佳的的電子傳遞。 Catalytic transfer hydrogenation (CTH) with liquid hydrogen donor is a promising approach to hydrogenate biomass derivatives as it is relatively convenient, low-cost, safe, and operated under milder conditions as compared to conventional high-pressure hydrogen process. In this work, we have prepared bulk g-C3N4 (b-CN) by thermal condensation of dicyandiamide precursor, and then converted b-CN into the nanosheet-like form (ns-CN) with thermal exfoliation. Pd nanoparticles were deposited onto b-CN and ns-CN supports by deposition-precipitation method to yield Pd/b-CN and Pd/ns-CN respectively. Physicochemical characterizations show that both b-CN and ns-CN support were synthesized with expected chemical structures. The fact that stacking of lamellar structure becomes looser and specific surface area is increased (18→51 m2 g-1) indicate the success of exfoliation. H2 chemisorption experiments reveal that Pd/ns-CN has a higher Pd dispersion. Charge transfer after Pd deposition is also confirmed from the decrease of photoluminescence intensity. The catalytic activity was evaluated by CTH of furfuryl alcohol to tetrahydrofurfuryl alcohol. Reaction testing shows that Pd/ns-CN exhibits a higher tetrahydrofurfuryl alcohol yield than that of Pd/b-CN, which may be attributed to the higher metal dispersion, more surface basic site, and enhanced charge transfer from CN support to Pd nanoparticles. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/50232 |
DOI: | 10.6342/NTU202002951 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學工程學系 |
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