請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/5258
標題: 溶膠-凝膠法/含浸法製備鈀觸媒於去除污染物CO及NO之研究
The activity of CO and NO of Pd catalyst prepared by sol-gel/impregnation methods
作者: 張祐甄
Chen, Chang Yu
關鍵字: Sol-gel
觸媒焚化
impregnation
palladium catalyst
activation energy
CO
NO.
溶膠-凝膠法
含浸法
CO
NO
活性測試
出版社: 環境工程學系
摘要: 台灣經濟繁榮,帶動工商發展,但隨之而來的污染問題,卻是值得關注的焦點。台灣目前多以焚化的方式處理廢棄物,因其能將廢棄物分解轉換為最終的穩定態,具有安定化、減量化、資源化及無害化的優點。而觸媒焚化能在較低溫度下反應且降低NOx之排放,現已廣泛應用於空氣污染防制上。 本研究主要採兩種不同的觸媒製備方式( 溶膠-凝膠法及含浸法 )製備出Pd觸媒,製備的方式為以溶膠-凝膠法將載體( Al2O3-SiO2 )製備出來,再以含浸的方式將活性相金屬Pd負載於其上;另一種為直接以溶膠-凝膠法將活性相金屬及載體一同製備,並將製備出的觸媒作物理化學結構分析,分析項目有:BET比表面積、 XRPD結晶物種分析、FESEM表面形貌觀察、TEM微結構及EDS元素分析等,觸媒的活性測試則是使用石英反應器且採連續進流方式,通入污染物氣體CO進行催化氧化反應,並探討同時去除污染物CO及NO之可能性。 研究結果指出,使用不同的製備方式所得到的觸媒,以含浸法製備的觸媒擁有較大比表面積,孔洞體積與平均孔徑上亦同,並孔洞大都落在中孔範圍。雖使用不同製備方式,在結晶物種上並無太大差異。在觸媒微結構的分析上,溶膠-凝膠法製備出的活性相Pd金屬粒子遠小於使用含浸法所製備的Pd金屬粒子,且分散性佳,較無團聚現象,此結果亦反應於觸媒活性測試上。以CO作活性測試結果,溶膠-凝膠法製備的觸媒其活化能小於含浸法製備的觸媒,顯示其觸媒活性亦是溶膠-凝膠法製備的觸媒優於使用含浸法製備的觸媒。 當同時去除CO及NO兩種污染物時,反應溫度是一影響去除率的重要因素,但NO去除率欲增加時需要大量CO來作為還原劑,因此有CO過量之問題,故在同時處理CO及NO時,還需考慮還原劑的添加。
The object of this research was to investigate the effects of different preparation methods on activity performances of palladium (Pd) catalysts. The Pd catalysts were prepared by sol-gel and impregnation methods, respectively. In the former process, support and Pd active site were synthesized in one step during the sol-gel method; in the latter process, support was synthesized by sol-gel method firstly, and then the coating with Pd active site on its surface with impregnation method. The physical texture and chemical character of Pd catalysts were characterized with BET surface area, X-ray powder diffraction (XRPD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS). The activity performances of Pd catalysts were evaluated by CO oxidation which tested with quartz reactor continuously. Furthermore, the possibility of removing CO and NO simultaneously by Pd catalysts were also investigated. The results indicated that the catalyst prepared by impregnation method has larger specific surface area than that prepared with sol-gel ones and the crystalline species were little different. However, the particle size of Pd catalysts which prepared by sol-gel method is much smaller than that prepared by impregnation method. Furthermore, the results also exhibited that the Pd catalysts prepared by sol-gel method had higher activity and showed lower activation energy than that prepared by impregnation method. The results might deduce that the Pd catalyst prepared by sol-gel method can improve the dispersion of Pd catalyst and then resulted in high activity. For removal of CO and NO simultaneously, the results showed that the removal efficiency of NO could be improved by adding CO agent at stoichiometry (CO/NO) equal to 2.5, but this may result in excess of CO.
URI: http://hdl.handle.net/11455/5258
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