硬模板法制备中孔LaMnO(3＋δ)钙钛矿及其甲烷燃烧催化性能  

Preparation of mesoporous LaMnO_(3+δ) perovskite by hard template method and its catalytic performance for methane combustion

作　　者：郭谨玮 蔡静文[1] 陈亚中[1] 王琪[1] 崔鹏[1] Guo Jinwei Cai Jingwen Chen Yazhong Wang Qi Cui Peng(Anhui Key Laboratory of Controllable Chemical Reaction and Material Chemical Engineering,School of Chemistry and Chemical Engineering,Hefei University of Technology ,Hefei 230009, Chin)

机构地区：[1]合肥工业大学化学与化工学院,可控化学与材料化工安徽省重点实验室,安徽合肥230009

出　　处：《无机盐工业》2017年第3期65-69,共5页Inorganic Chemicals Industry

基　　金：国家自然科学基金资助项目(NSFC21476055)

摘　　要：利用三维有序结构SBA-15分子筛为硬模板剂,在其孔道内填充La^(3+)、Mn^(3+)柠檬酸络合物,经过焙烧并去除模板剂得到中孔结构的LaMnO_(3+δ)钙钛矿。采用低温氮气物理吸附、氧气-程序升温脱附(O2-TPD)、X射线衍射(XRD)、X射线光电子能谱(XPS)对LaMnO_(3+δ)进行表征,考察了LaMnO_(3+δ)甲烷燃烧催化性能,并与溶胶-凝胶法制备的LaMnO_(3+δ)进行比较。结果表明,硬模板法制备的LaMnO_(3+δ)具有更高的比表面积(45.2m2/g),其甲烷起燃温度(T10)和半转化温度(T50)分别为318℃和480℃,而溶胶-凝胶法制备的LaMnO_(3+δ)的T10和T50分别为380℃和532℃。O2-TPD和XPS表征结果表明,硬模板法制备的LaMnO_(3+δ)存在更多的Mn4+和表面吸附氧物种,其非化学计量比氧更高,使得催化剂具有更好的活性。Mesoporous LaMnO3＋δ perovskite was synthesized by filling the La^3＋, Mn^3＋ citrate complex precursor into the pores of mesoporours material SBA-15, which was used as hard-template, followed by calcination and template removal.The sample was characterized by low temperature N2 absorption, oxygen temperature programmed desorption （O2-TPD）, XRD, and XPS, and the catalytic performances for methane combustion were measured.Compared with the perovskite prepared by sol-gel method, the sample by hard-template method showed a higher surface area （45.2 m^2/g） and typical mesoporous structure.The light-off temperature （Tlo） and the half-conversion （Ts0） were 318 ℃ and 480 ℃ ,while the corresponding temperatures for LaMnO3＋δ prepared by sol-gel were 380 ℃ and 532 ℃, respectively.The O2-TPD and XPS characterization indicated that the presence of high valence manganese ions resulted in high non-stoichiometric oxygen in LaMnO3＋δ prepared by hard template method ,which were beneficial to high content of surface oxygen and high activity.

关 键 词：硬模板 SBA-15 LaMnO3+δ钙钛矿 甲烷燃烧 催化性能 

分 类 号：TQ131.3[化学工程—无机化工]