本研究以濕式含浸法將硝酸鈰、硝酸銅均勻分佈於椰殼纖維中，經熱裂解高溫燒結製備出具高度還原活性之活性碳觸媒並應用於去除氮氧化物。研究中以比表面積分析儀(BET)、環境掃描式電子顯微鏡(SEM)與X射線能量分散分析儀(EDS)分析活性碳觸媒之結構與孔隙特性特性，並探討硝酸鈰、硝酸銅雙金屬製備出含不同濃度金屬之活性碳觸媒之還原性及還原劑濃度比例變化及還原反應溫度等操作條件變化對選擇性觸媒還原反應(SCR)及非選擇性觸媒還原反應(NSCR)之氮氧化物(NOx)還原效率之影響。本研究以鈰、銅活性碳觸媒進行選擇性觸媒還原法(SCR)及非選擇性觸媒還原法(NSCR)根據研究結果顯示，含浸低濃度銅金屬可製備得高孔隙率及比表面積，其中銅系列活性碳觸媒含浸濃度0.025M時，活性碳觸媒比表面積最高達729m2/g，而含浸高濃度鈰金屬之活性碳觸媒孔隙率及比表面積較低，含浸濃度0.1M鈰金屬時，活性碳觸媒比表面積最低達335 m2/g，鈰、銅活性碳觸媒孔隙以微孔為主。應用所製備之鈰、銅活性碳觸媒於選擇性觸媒還原反應皆具有良好之還原活性，在200℃還原反應溫度下，銅系金屬具有較鈰系金屬更高之催化活性，其中Ce-4活性碳觸媒NO還原率可達100%，而鈰金屬在同樣反應溫度下並無法呈現太大之活性，在非選擇性還原法中，450℃還原反應溫度下，則是鈰金屬方能具有良好催化活性，Ce-4活性碳觸媒還原率達100%為最佳，而鈰金屬活性仍較銅金屬佳。選擇性觸媒還原系統中以銅型活性碳觸媒較佳，而在於非選擇性觸媒還原法系統中則以鈰型活性碳觸媒較佳。在選擇性觸媒還原法中，鈰/銅比等於1時，鈰/銅型活性碳觸媒活性較鈰活性碳觸媒增加，結果中顯示添加銅金屬提升鈰金屬還原活性。本研究得知活性碳觸媒之氮氧化物還原活性取決於觸媒比表面積大小、活性金屬種類、觸媒活性金屬含量、及適當金屬分散性才有助於提升碳觸媒於SCR及NSCR還原性能。 The preparation of activated carbon catalysts with highly reductive activity of DeNOx were investigated by wet impregnation method with cerium nitrate and copper nitrate into coconut shell. The pore and characteristics of surface properties of activated carbon catalysts were observed by the BET and SEM-EDS analysis. The effect of nature of impregnated metal, metal concentration, and operating conditions on the reduction activity in the SCR and NSCR were investigated. The property changes of those properties on the performance of catalytic reduction of activated carbon catalysts were also discussed. In this study, cerium, copper and cerium/copper type activated carbon were prepared and they were used for NOx reduction by SCR and NSCR method. It was found that the high specific surface areas of copper type activated carbons were made with low concentration impregnated in coconut shell. The specific surface area can be achieved up to 729 m2/g with 0.025M copper impregnated in the preparation. On the other hand, the higher concentration cerium impregnated decline the surface area and changed the pore properties of catalyst. The pore sizes of catalyst are mainly in the range of micropore size. The high reduction properties of all catalysts were observed in this study. The completely removal of NOx was achieved at 200℃ with copper type catalyst in SCR. On the other hand, the completely removal of NOx was achieved with cerium type catalyst in NSCR at 450℃. In the case of NSCR system, the reduction performance of cerium catalyst is superior to the copper type catalyst with suitable metal content in the carbon. It is concluded that the best reduction activity of copper type catalyst was found in SCR. On the other hand, the reduction activity of cerium type catalyst presented superior performance than copper type in NSCR system. The copper embedded significantly enhanced the reduction activity of catalyst in the bimetal catalysts. It was concluded that the surface area, nature of active metal, metal content in catalyst, and the active site distribution were the key factors to dominated the reduction activity of catalyst in SCR and NSCR system.
