钙钛矿结构钛酸铅四方板状颗粒的水热合成及表征

Hydrothermal synthesis and characterization of lead titanate perovskite tetragonal microplates

以层状结构的 K2 Ti6 O13纳米纤维为钛源,成功实现了钙钛矿结构钛酸铅四方板状颗粒的合成。分别利用 XRD、SAED、SEM、TEM、HRTEM对其物相和微观形貌进行了表征。结果显示,所合成的 Pb-TiO3四方板状颗粒平行于（101）晶面,厚度约为200-300 nm,边长约为1-2μm。基于水热处理时间对物相和形貌演化的影响,讨论了 PbTiO3四方板状颗粒形成机理。发现层状结构 K2 Ti6 O13对 PbTiO3四方板状颗粒的形成具有重要作用。在水热处理过程中,Pb2＋离子取代 K2 Ti6 O13结构中的 K＋离子,导致层状剥离,形成钛酸铅片状基元,结晶形成中间相 Pb-Ti0.8 O2.6,进而转化为钙钛矿结构PbTiO3二维板状四方颗粒。

Lead titanate （PbTiO3 ）perovskite tetragonal microplates have been successfully synthesised via a conventional hydrothermal route by employing K2 Ti6 O13 as titanium source.XRD,SAED,SEM,TEM and HRTEM were employed to characterize the products.The results reveal that the PbTiO3 tetragonal microplates are dominated with （101）facets.The thickness and lateral size of the PbTiO3 microplates are about 200-300 nm and 1-2μm,respectively.With the basis of the time-dependent experimental results,the formation mechanism of the PbTiO3 tetragonal microplates was discussed.Generally,the layered K2 Ti6 O13 plays an important role in the synthesis of the PbTiO3 tetragonal microplates.During the hydrothermal treatment,Pb2＋ ions diffuse into the structure of K2 Ti6 O13 and replace the K＋ ions,resulting in the sheet-like lead titanate species.The sheet-like lead titanate species nucleate to the intermediate phase of PbTi0.8 O2.6 and then this intermediate phase transforms and grows to PbTiO3 tetragonal microplates.