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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/3969


    Title: 氧化矽擔載銅觸媒應用於甲醇部分氧化 產製氫氣之研究;Production of hydrogen via partial oxidation of methanol over Cu/SiO2 catalysts
    Authors: 黃至瑋;Chih-Wei Huang
    Contributors: 化學工程與材料工程研究所
    Keywords: 銅觸媒;甲醇部分氧化反應;氫氣;hydrogen;partial oxidation of methanol;depos
    Date: 2007-01-09
    Issue Date: 2009-09-21 12:27:19 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 本研究以二氧化矽為擔體,利用沉澱固著法製備成二氧化矽擔載銅觸媒,目的在發展甲醇部分氧化反應(CH3OH + 1/2O2 → 2H2 + CO2)產製氫氣的程序,並以不同銅載量及煅燒溫度等變因深入探討,同時利用感應耦合電漿質譜分析儀(ICP-MS)、熱重分析儀(TGA)、程式升溫還原(TPR)、N2O 分解吸附(dissociative adsorption of nitrous oxide)、X 射線繞射儀(XRD)、穿透式電子顯微鏡(TEM)、掃描式電子顯微鏡(SEM)、X 射線光電子分析儀(XPS)等各項儀器與分析技術,分別對擔體及觸媒進行鑑定,藉以評估觸媒應用於質子交換膜燃料電池的可行性。從化性結果分析,8.7wt% Cu/SiO2 觸媒催化最好,具有高氫氣選擇率和低一氧化碳選擇率,從N2O 分解吸附數據發現,銅粒徑隨著銅金屬載量提高而變大,從1.3nm 增加到3.4nm。TPR 的分析結果發現,氧化銅的還原峰隨著煅燒溫度增加往低溫偏移,經過煅燒程序後銅金屬分散度變大及吸附在擔體上的銅粒子接觸面積變小使擔體效應變小,因此造成Cu/SiO2 觸媒較容易還原;由XPS 的結果中發現,在甲醇部分氧化反應中,銅觸媒中Cu0 金屬銅是反應的活性物種,Cu2+則對甲醇部分氧化反應沒有活性,但是Cu/SiO2 觸媒的擔體二氧化矽具有高比表面積、熱穩定性及高催化活性等優點。經過活性測試後發現,Cu/SiO2 觸媒的活性與金屬銅的表面積成線性關係。當金屬銅的表面積越大時,氫氣選擇率越高;另外進料中氧氣與甲醇的比例也是影響反應的一個因素,當O2/CH3OH = 0.3 時,一氧化碳的產量較低,當增加反應溫度時,甲醇轉化率與氫氣選擇率都會同時增加。反應路徑由連續的甲醇部分氧化轉變成甲醇直接分解與甲醇蒸汽重組反應構成,使一氧化碳選擇率隨反應溫度提高而增加。Cu/SiO2 觸媒擁有高甲醇轉化率與氫氣轉擇率,但是Cu/SiO2 觸媒的一氧化碳選 擇率相對比貴重金屬觸媒的一氧化碳選擇率高,未來仍須進行Cu/SiO2 觸媒改質,以降低一氧化碳選擇率。 In this work silica-support copper catalysts were investigated for partial oxidation of methanol (CH3OH + 1/2O2 → 2H2 + CO2) to produce hydrogen. Cu/SiO2 catalysts prepared by deposition-precipitation method with different loadings were studied in detail. The structural characteristics of Cu/SiO2 were analysed by ICP-MS, TGA, TPR, N2O,XRD, SEM, TEM, and XPS. This catalysts show high activity for POM.The kinetic results show that the catalyst with 8.7wt%Cu/SiO2 exhibits the highest H2 selectivity and lowest CO selectivity than other catalysts.N2O adsorption chemisorption was used to monitor the surface area and particle size. The size of the copper particles increases from 1.3 nm to 3.4 nm with increasing loadings. TPR measurements revealed that the reduction temperature of CuO shifts to the lower temperature with increase in the calcination temperature. The position of TPR peak shifts to the lower temperature suggesting the reducibility of CuO was promoted;XPS analyses demonstrated that Cu0 in catalysts is an active specie, but Cu2+ is not during the POM reaction. The activity of the catalyst is linearly dependent on the metallic copper surface area. All the results conclude that silica-support copper catalysts have highly copper dispersion and metallic copper surface area. The Cu/SiO2 catalysts display great activity for the conversion of methanol to produce hydrogen.
    Appears in Collections:[化學工程與材料工程研究所] 博碩士論文

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