沉淀转化法制备多孔片状纳米LaF_3

Preparation of Porous LaF_3 Nanoplates via Precipitation-Transforming-Method

采用实验中所合成的LaPO4纳米棒为前驱体,通过沉淀的转化作用,大面积地制备了单分散的片状纳米LaF3。采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、BET(Brunauer-Emmett-Teller)测试对片状纳米LaF3的形貌、结构、相组成及表面性质进行了分析。片状纳米LaF3底边长约为40 nm,片的厚度约为35 nm,大小均一,具有多孔结构。通过改变反应溶剂,可以控制LaF3粒子的成核、生长和团聚,从而有效地调控多孔片状纳米LaF3的颗粒尺寸和分散性。对多孔片状纳米LaF3的生长机制进行了研究,结果表明LaPO4和LaF3的溶度积常数差导致了片状纳米LaF3的生成;体系中自身存在的Ostwald ripening作用使片状纳米LaF3出现了多孔结构。

The monodisperse LaF3 nanoplates with large-scale,were prepared using as-synthesized LaPO4 nanorodes as precursors by a precipitation-transforming-method（PTM）.The phase,morphology and structure of the products were characterized by powder X-ray diffraction（XRD）,scanning electron microscopy（SEM） and transmission electron microscopy（TEM）,and selected-area electron diffraction（SAED）,indicative of crystalline phase and quasi-hexagonal porous prism morphology of LaF3 with the length of 40 nm and the height of 35 nm.The organic solvent played a vital role in the synthesis and made great effects on the morphology of the products.The research on the growth mechanism of porous LaF3 nanoplates showed that the difference of the solubility-product constant between LaPO4 and LaF3 made great effect on transforming LaPO4 nanorodes to LaF3 nanoplates,while the Ostwald ripening in the reaction system played a role in obtaining porous-structure of LaF3 nanoplates.