複合型二氧化鈦鈰鉍鋯氧化觸媒對乙醛氧化及光催化之研究

NCU Institutional Repository > 工學院 > 化學工程與材料工程研究所 > 博碩士論文 > Item 987654321/73938

請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/73938

題名:	複合型二氧化鈦鈰鉍鋯氧化觸媒對乙醛氧化及光催化之研究
作者:	李帛樺;Lee, Po-Hua
貢獻者:	化學工程與材料工程學系
關鍵詞:	揮發性有機化合物氧化;光催化活性;乙醛;鈰鉍鋯氧化觸媒;貴金屬;VOCs oxidation;photocatalytic activity;acetaldehyde;CeO2-ZrO2-Bi2O3 catalyst;noble metal
日期:	2017-06-29
上傳時間:	2017-10-27 12:55:15 (UTC+8)
出版者:	國立中央大學
摘要:	揮發性有機化合物是一種在常溫常壓下具高蒸汽壓和易蒸發性的有機化學物質。揮發性有機化合物污染多屬於逸散性排放，倘若散發於環境中，經陽光照射會與氮氧化物產生臭氧濃度上升及光化學煙霧等環境污染問題。近年來，室內空氣品質的問題亦逐漸受到國人重視，尤其許多現代化建築多為密閉型態，當室內換氣量不足時，污染物容易累積造成室內空氣品質的惡化，如裝潢使用的合板建材所含有的甲醛和乙醛，已證明具有刺激性且為致癌性物質。針對有效減少揮發性有機化合物的排放已經有多種方法，如催化燃燒，火焰燃燒，使用臭氧和電漿的催化分解，光催化分解，和依賴吸附劑的方法等，這些方法中，催化燃燒具以下特點：（i）在低溫下可以進行稀釋燃料的完全燃燒;（ii）能實行極低排放的氮氧化物和未燃燒的燃料。一般來說，低溫下使用負載貴重金屬的觸媒對揮發性有機化合物具有較高的氧化活性。在負載的貴金屬觸媒中，由於其對於各種反應的高活性以鉑-觸媒較為常見。本研究目的是製備複合型二氧化鈦鈰鉍鋯氧化觸媒，在常溫下針對乙醛的氧化及光催化之研究。鈰鉍鋯氧化物觸媒利用共沉澱法以不同鍛燒溫度製備，再以物理方法和二氧化鈦粉末摻混，及利用含浸法加入少量鉑金屬。研究的反應實驗包含，使用亞甲基藍水溶液作為有機污染物進行光催化活性試驗，和測試乙醛的催化氧化的效率。製備的樣品將經下列儀器分析鑑定: ｘ光粉末繞射儀（XRD），氮氣吸附孔隙儀(ASAP)，穿透式電子顯微鏡(TEM)，超高解析可變真空場發射掃描式電子顯微鏡（HRTEM），能量色散光譜儀（EDS），紫外-可見分光光度計(UV-Visible Spectrophotometer)和氣相色譜儀（GC）。 XRD圖在觸媒Ce68Bi17Zr15(550)和Ce68Bi17Zr15(800)都顯示出良好的結晶性。在2wt%Pt/19.6wt% Ce68Bi17Zr15(550)+ TiO2觸媒沒有觀察到金屬鉑的訊號，代表出鉑的粒徑小於偵測極限4奈米。 BET分析顯示Ce68Bi17Zr15(550)的表面積與Ce68Bi17Zr15(800)的表面積大致相同，代表都形成了良好的結晶氧化物。TEM圖像顯示Ce68Bi17Zr15(550)的平均粒徑小於Ce68Bi17Zr15(800)的平均粒徑，鉑顆粒的粒徑為2.69〜3.52奈米，與XRD的結果一致。從HR-TEM的結果可以觀察到Ce68Bi17Zr15(550)和Ce68Bi17Zr15(800）中CeO2-ZrO2-Bi2O3的晶格條紋，亦觀察到金屬鉑顆粒在載體上均勻分散。光催化活性試驗中，反應條件設定在室溫並通過UVC照射，亞甲基藍均可以由20wt%Ce68Bi17Zr15(550)+TiO2, 20wt%Ce68Bi17Zr15(800)+TiO2 和2wt%Pt/19.6wt% Ce68Bi17Zr15(550)+ TiO2觸媒分解，又以20wt%Ce68Bi17Zr15(800)+TiO2觸媒表現最佳光催化活性；比較UVC照射方向，發現自頂部照明的反應器速率常數較大，表明在此狀態下亞甲基藍的轉化率較高。常溫下觸媒催化乙醛實驗中可以觀察到經UVC光照射Ce68Bi17Zr15(550)和Ce68Bi17Zr15(800)觸媒去除乙醛能力均增加，但Ce68Bi17Zr15(800)的反應表現較佳；2wt%Pt/19.6wt% Ce68Bi17Zr15(550)+ TiO2觸媒與TiO2相比，前者在室溫下可以顯著提高乙醛的去除率，推測是鉑金屬的均勻分散使得反應活性提高。鈰鉍鋯觸媒在室溫下對乙醛具有氧化及吸附的能力，預測此觸媒可應用於去除還原力相對較強的甲醛。 ;Volatile organic compounds (VOCs) have relatively high vapor pressure and thus easily vaporize under ambient conditions. VOCs are known to cause air pollution and compared with various solutions, catalytic combustion has advantageous features for VOCs removal: (i) complete combustion of dilute fuel proceeds stably at low temperatures; (ii) extremely low emission of NOx and unburned fuels can be achieved. In general, supported precious metal catalysts exhibit high activity for low-temperature oxidation of VOCs. Among supported precious metal catalysts, platinum catalysts are known to be active for various catalytic reactions. The aim of this study is to develop composite titanium dioxide CeO2–ZrO2–Bi2O3 catalyst with destruction efficiency for acetaldehyde at room temperature. Several CeO2–ZrO2–Bi2O3 catalysts were prepared, including by co-precipitation calcined at different temperature, blending with TiO2 and loading few amount of platinum by impregnated method. For the reaction test, methylene blue aqueous solution was used as organic pollutant for photocatalytic activity test and catalytic oxidation of acetaldehyde was examined. The samples were characterized in detail. The XRD patterns showed high crystalline for both CeO2–ZrO2–Bi2O3 catalysts calcined at 550 and 800 oC, respectively. No platinum peaks were observed in 2wt%Pt/19.6wt% Ce68Bi17Zr15(550)+TiO2 which present that the particle size of Pt was too small to detect. The BET analysis showed that the surface area of Ce68Bi17Zr15(550) was about the same as that of Ce68Bi17Zr15(800), indicating the formation of well crystalline oxide compound. The TEM images indicate that the average particle size of Ce68Bi17Zr15(550) was smaller than that of Ce68Bi17Zr15(800) and the particle size of platinum was 2.69 - 3.52 nm which is in agreement with the results of XRD. From the result of HR-TEM, the crystalline lattice fringes of CeO2-ZrO2-Bi2O3 solid solution was observed both in Ce68Bi17Zr15(550) and Ce68Bi17Zr15(800) and could observe the Pt particle disperse well on the support. For the photocatalytic activity test, methylene blue was decomposed by 20wt%Ce68Bi17Zr15(550)+TiO2, 20wt%Ce68Bi17Zr15(800)+TiO2 and 2wt%Pt/19.6wt% Ce68Bi17Zr15(550)+TiO2 under UVC illumination at room temperature respectively and the 20wt%Ce68Bi17Zr15(800)+TiO2 catalyst showed the highest photocatalytic activity. Compared the UV light illuminated direction, as the entire surface could be exposed under UVC light, it was observed that the rate constant of reactor illuminated by top was larger, indicating higher conversion of methylene blue. Illuminated under UVC light, Ce68Bi17Zr15(550) and Ce68Bi17Zr15(800) catalysts were observed that the removal of acetaldehyde increased and the Ce68Bi17Zr15(800) catalyst showed the higher activity than Ce68Bi17Zr15(550) catalyst with or without UVC light illumination. For 2wt%Pt/19.6wt% Ce68Bi17Zr15(550)+ TiO2 catalyst, it could improve the oxidation activity to remove acetaldehyde at room temperature compared with TiO2. Acetaldehyde could be remove under Ce-Zr-Bi catalysts at room temperature and we expect the catalyst could be extended to oxidize formaldehyde that has relatively strong reduction.
顯示於類別:	[化學工程與材料工程研究所] 博碩士論文

文件中的檔案:

檔案	描述	大小	格式	瀏覽次數
index.html		0Kb	HTML	417	檢視/開啟

在NCUIR中所有的資料項目都受到原著作權保護.

社群 sharing

資料載入中.....