摘要
用柠檬酸溶胶 凝胶法制备LaMnO3+λ,La0 .6 Ce0 .4 MnO3+λ和La0 .6 Sr0 .4 MnO3+λ稀土纳米材料 ,并通过差热 -热重分析 (DTA TGA)、X射线衍射分析 (XRD)、透射电镜 (TEM)和Brunauer Emmett Teller(BET)比表面分析等方法研究了Ce和Sr对纳米钙钛矿材料结构和性能的影响。制备得到 60nm的LaMnO3+λ、10 0nm的La0 .6 Ce0 .4 MnO3+λ及 30nm的La0 .6 Sr0 .4 MnO3+λ。当Sr在LaMnO3+λ中部分取代La时 ,Sr进入了钙钛矿晶格 ,从而能降低钙钛矿形成温度 ,减小颗粒度 ,增大比表面 ;但对Ce而言 ,取代时很难进入钙钛矿晶格 ,主要以CeO2 形式存在 ,同时可提高钙钛矿形成温度 ,增大颗粒度 ,减小比表面。
Nanometer perovskite LaMnO 3+ λ , La 0 6 Ce 0 4 MnO 3+ λ and La 0 6 Sr 0 4 MnO 3+ λ were prepared by citric acid sol gel method. The effects of Ce and Sr on the structure and properties of nanometer perovskite were studied through DT-TGA, XRD, TEM and BET analysis. The results show that, by sol gel method, LaMnO 3+ λ , La 0 6 Ce 0 4 MnO 3+ λ and La 0 6 Sr 0 4 MnO 3+ λ are made with the average particle sizes of about 60, 100 and 30 nm, respectively. After partially substituting with Sr for La position in LaMnO 3+ λ , it is found that Sr is located at the lattice of perovskite so as to reduce the forming temperature of perovskite. As a result, the perovskite has smaller particle size and larger special surface area. On the contrary, it is difficult for Ce to enter the lattice of perovskite, and most of the cerium additives exist in CeO 2 when La in LaMnO 3+ λ is partially substituted with Ce. The forming temperature of perovskite is increased, and it has bigger particle size and less special surface area.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2001年第4期338-342,共5页
Journal of the Chinese Society of Rare Earths
基金
教育部首批高等学校骨干教师资助计划项目 ( 2 0 0 0~ 2 0 0 1)
