碱土元素掺杂的BaFeO3钙钛矿型催化剂的NOx储存性能  

NO_x Storage Performance of Alkaline Earth-Doped Perovskite-Type BaFeO_3 Catalysts

作　　者：李锋丽[1] 郭丽[1] 贤晖[1] 孟明[1] 李志军[2] 鲍骏[3] 李新刚[1] 

机构地区：[1]天津大学化工学院天津市应用催化科学与工程重点实验室,天津300072 [2]天津大学内燃机燃烧学国家重点实验室,天津300072 [3]中国科学技术大学国家同步辐射实验室,合肥230029

出　　处：《物理化学学报》2013年第3期605-611,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(U1162103,U1232118);国家高技术研究发展计划(863)(2008AA06Z323);天津市自然科学基金(11JCYBJC03700);教育部新世纪优秀人才支持计划(NCET-10-0615);教育部留学归国人员科研启动基金(2011-1568);天津大学内燃机燃烧学国家重点实验室开放基金(K2012-05)资助项目~~

摘　　要：采用溶胶-凝胶法制备了Ba1-xMxFeO3(M=Mg,Ca,Sr;x=0,0.1,0.2)系列钙钛矿型NOx储存还原(NSR)催化剂,考察碱金属元素Mg、Ca和Sr的掺杂对BaFeO3钙钛矿NOx储存和氧化性能的影响.结果表明,在250-400°C范围内Mg的掺杂提高了BaFeO3钙钛矿的NOx储存性能,其中以Ba0.8Mg0.2FeO3样品的NOx储存性能最佳,在温度350°C时NOx储存量高达1200μmol·g-1以上,NO→NO2转化率为53.4%.与BaFeO3比较,Ba0.8Mg0.2FeO3样品在250°C进行NOx储存时就出现了单齿硝酸盐,并随储存温度的变化而变化,它的数量与NOx储存量有相同的变化趋势.傅里叶变换红外(FTIR)光谱结果表明,与BaFeO3相比,Ba0.8Mg0.2FeO3样品NOx储存量增大的原因在于:一方面,形成了具有A位缺陷的钙钛矿结构,产生大量能够用于储存NOx的氧空位;另一方面,未进入钙钛矿晶格的Mg元素可能以碱性氧化物的形式与NOx作用形成了单齿硝酸盐.A series of Ba 1-x M x FeO 3 （M=Mg,Ca,Sr;x=0,0.1,0.2） perovskites were prepared by the sol-gel method as NO x storage reduction （NSR） catalysts.The effect of doping with alkaline earth metals （Mg,Ca,and Sr） on the NO x storage and oxidation performance of the BaFeO 3 perovskites was investigated.Doping with Mg enhanced the NO x storage capacity （NSC） of the BaFeO 3 perovskites in the temperature range 250-400 °C,the Ba 0.8 Mg 0.2 FeO 3 perovskite exhibited the best NO x storage performance,which reached its maximum at 350 °C,with NSC1200 μmol · g-1 and NO→NO2 conversion of 53.4%.Compared with BaFeO3,the monodentate nitrate appeared clearly for the Ba0.8Mg0.2FeO3 sample after storing NOx at 250℃.The amount of the monodentate nitrate on Ba0.8Mg0.2FeO3 varied with the NOx storage temperature in a similar manner to that of its NSC.Fourier transform infrared （FTIR） spectra indicated that doping with Mg induced an A-site deficient perovskite structure in BaFeO3,which readily generates oxygen vacancies that act as the active sites for NO x adsorption.Moreover,the residual MgO on the catalyst might also improve the NSC of the sample by forming the monodentate nitrate.

关 键 词：钙钛矿 碱土金属掺杂 NOx储存 NO氧化 稀燃 

分 类 号：O643.36[理学—物理化学]