Na_(0.5)Bi_(0.5)TiO_3纳米纤维的制备及形成机理研究

Hydrothermal Synthesis of Bismuth Sodium Titanate Nanowires and Forming Mechanism

以Bi（NO3）3 5H2O、板状钛酸（H1.07Ti1.73O4 nH2O）、NaOH为原料,采用水热法合成了具有钙钛矿结构的Na0.5Bi0.5TiO3纳米纤维.利用X射线衍射仪（XRD）、场发射扫描电镜（FESEM）、透射电镜（TEM）和X射线能谱仪（EDS）对产物进行表征.通过考察在200℃下水热反应不同时间的产物的相结构、微观形貌及化学组成,对Na0.5Bi0.5TiO3纳米纤维的形成机理进行了探讨.结果表明：钛酸H1.07Ti1.73O4 nH2O是一类具有层板结构的化合物,在水热反应过程中,板状钛酸的层间H3O＋可与Na＋、Bi3＋进行离子交换,通过原位生长的方式形成了板状Na0.5Bi0.5TiO3颗粒,随着水热反应的进行,板状Na0.5Bi0.5TiO3颗粒裂解形成纳米纤维.所得的Na0.5Bi0.5TiO3纳米纤维分散性好,具有钙钛矿结构,直径为30-150 nm,长度为几个微米到十几个微米.

The Na0.5Bi0.5TiO3 nanowires with perovskite structure were successfully synthesized by the hydrothermal method using Bi（NO3）3 5H2O,H1.07Ti1.73O4 nH2O and NaOH as the starting materials.The products were characterized by X-ray powder diffraction（XRD）,field emission scanning electron microscope（FESEM）,transmission electron microscope（TEM） and energy dispersive spectroscope（EDS）,respectively.The phase structure,morphology,and chemical compositions of products synthesized at 200℃ by hydrothermal process for different times were investigated and the forming mechanism of nanowires was introduced.The results indicate that H1.07Ti1.73O4 nH2O is a compound with lepidocrocite-like layered structure,and the Na＋,Bi3＋ ions can exchange with H3O＋ in the interlay space of plate-like titanates in the hydrothermal process.Then the plate-like titanates are transformed into plate-like Na0.5Bi0.5TiO3 particles by in situ reaction.With the hydrothermal reaction progressing,the plate-like Na0.5Bi0.5TiO3 particles split into nanowires.The nanowires are well dispersed with perovskite structure.The width of nanowire is ranging from 30 nm to 150 nm and the length is about several micrometers to tens of micrometers.