摘要
分别以Ce_2(C_2O_4)_3和Ce(SO4)2为Ce前驱体,采用固相球磨法制备了Ce基选择性催化还原(SCR)脱硝催化剂CeTiO_x-A[以Ce_2(C_2O_4)_3为前驱体]和CeTiO_x-B[以Ce(SO4)2为前驱体].将2个催化剂分别在体积分数为0. 15%的SO2的气氛下反应40和60 h,得到高硫条件下SCR反应后的CeTiO_x催化剂,分别记为40CeTiOx-A,60CeTiOx-A,40CeTiOx-B和60CeTiOx-B.考察了反应前后催化剂的NH_3-SCR反应活性.采用X射线衍射(XRD)、X射线荧光光谱(XRF)、比表面积(BET)测试、H2程序升温还原(H2-TPR)、X射线光电子能谱(XPS)、NH_3程序升温脱附(NH_3-TPD)及SO2程序升温脱附(SO2-TPD)等技术对样品进行了表征.结果表明,CeTiO_x-A系列催化剂比CeTiO_x-B系列催化剂具有更高的NH_3-SCR反应活性和更好的抗硫抗水性能.与CeTiO_x-B系列催化剂相比,CeTiO_x-A系列催化剂具有更大的比表面积和孔容,更多的Ce^(3+)和吸附氧(Oα)物种有助于NO的吸附和活化; CeTiO_x-A系统催化剂还具有更多的Lewis强酸性位数量,可以吸附更多的NH_3分子,有利于催化剂上NH_3-SCR反应的进行,提高了CeTiO_x-A系列催化剂的NO转化率.
Ceria-based catalysts( CeTiOx-A and CeTiOx-B) were prepared by solid state ball milling method with Ce2(C2O4)3 and Ce( SO4)2 as precursors,respectively. Then,the prepared ceria-based catalysts were treated in reaction atmosphere consisted of 0. 15% SO2 for 40 and 60 h,respectively. The obtained catalysts were designated as 40 CeTiOx-A,60 CeTiOx-A,40 CeTiOx-B and 60 CeTiOx-B. The performances of fresh and used catalysts for selective catalytic reduction( SCR) of NO with NH3 as the reductant were investigated. The catalysts were also characterized using X-ray diffraction( XRD),X-ray fluorescence spectra( XRF),Brunner emmet teller( BET),H2-temperature programmed reduction( H2-TPR),X-ray photoelectron spectra( XPS),NH3-temperature programmed desorption( NH3-TPD) and SO2-temperature programmed desorption( SO2-TPD)techniques. The results indicated that the NH3-SCR activity,SO2 and H2 O resistance over the CeTiOx-A catalysts were better than over the CeTiOx-B samples. The reasons for this phenomenon are that CeTiOx-A catalysts possess larger specific surface area and pore volume than CeTiOx-B catalysts. Besides,CeTiOx-A catalysts have plenty of Ce3+and the surface adsorbed oxygen,which would benefit the adsorption and activation of NO. Furthermore,CeTiOx-A catalysts also have numerous strong Lewis acid sites,which lead to the increasing adsorption of NH3. Therefore,the NH3-SCR reaction rate and the NO conversion of CeTiOx-A catalysts was improved.
作者
朱红太
宋丽云
何洪
尹孟奇
程杰
孙炎明
李世宁
邱文革
ZHU Hongtai;SONG Liyun;HE Hong;YIN Mengqi;CHENG Jie;SUN Yanming;LI Shining;QIU Wenge(Key Laboratory of Beijing on Regional Air Pollution Control;Beijing Key Laboratory for Green Catalysis and Separation, Beijing University of Technology, Beijing 100124, China)
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第2期350-357,共8页
Chemical Journal of Chinese Universities
基金
国家重点研究发展计划(批准号:2016YFB0600405)
国家自然科学基金(批准号:21577005)资助~~
