作　　者： ; ; ; ; ;

机构地区： 四川大学化学工程学院绿色化学与技术教育部重点实验室

出　　处： 《催化学报》 2009年第3期247-253,共7页

摘　　要： 采用柠檬酸络合法制备了La0.75Sr0.25Mn1-xNixO3+δ(x=0,0.4,0.5和0.6)系列样品,考察了其对甲烷部分氧化的催化性能,并采用X射线衍射、H2程序升温还原、O2程序升温脱附和程序升温氧化等测试手段表征样品.结果表明,当x=0,0.4和0.5时,样品均形成稳定的钙钛矿结构;当x=0.6时样品同时存在钙钛矿和菱形六面体尖晶石结构.当x=0.5时样品存在4种可还原物种,同时具有高的表面氧特别是高的晶格氧含量,对甲烷部分氧化有利,这表明La0.75Sr0.25Mn0.5Ni0.5O3+δ具有良好的抗积炭性能.催化性能测试结果表明,当x=0.5时,样品具有良好的甲烷中温转化率,最高的CO和H2选择性,以及在700oC下最好的反应稳定性和抗积炭能力. A series of perovskites Lao.75Sr0.25Mn1-xNixO33＋δ （x = 0, 0.4, 0.5, and 0.6） were prepared by the citric chelating method. Methane partial oxidation was used to investigate the catalytic performance of the samples. The crystal structures were characterized by X-ray diffraction （XRD） and temperature-programmed reduction （H2-TPR）, temperature-programmed desorption of oxygen （O2-TPD）, and temperature-programmed oxidation （TPO）. XRD results showed that the unit cells of the samples with x〈0.6 were perovskite structures, and perovskites and spinel structure were detected with x = 0.6. The results of H2-TPR indicated that most of the reducible species were in La0.75Sr0.25Mn0.5Ni0.5O3＋δ, O2-TPD results showed that most of the movable oxygen species existed on the surface and in the lattice of La0.75Sr0.25Mn0.5Ni0.5O3＋δ; in combination with TPO results it can be concluded that La0.75Sr0.25Mn0.5Ni0.5O3＋δ had the best performance of resisting carbon deposition among the samples. The catalytic activity tests showed that with Ni doped in the B-sites of LaSrMnO3 perovskite,the methane conversion increased, and the highest selectivity for H2 and CO and good stability were found on the La0.75Sr0.25Mn0.5Ni0.5O3＋δ sample. In addition, this catalyst yielded a H2/CO molar ratio close to 2 at 700 ℃ and showed good resistance to carbon deposition.

关 键 词： 掺杂锰酸镧 镍 钙钛矿 甲烷部分氧化 固体氧化物燃料电池

领　　域： [理学] [理学]