H_2Ti_4O_9纳米带的制备及其水热反应

Preparation and solvothermal reaction of H_2Ti_4O_9 nanobelts

目的以K_2Ti_4O_9·3H_2O为主要原料,制备H_2Ti_4O_9·nH_2O纳米带,研究纳米带的结构与性能,为开发新型功能材料提供新靶点。方法 K_2Ti_4O_9·3H_2O与盐酸进行离子交换反应,其产物分别与乙二胺和四甲基氢氧化铵溶液进行剥离反应,形成胶体再与Ba(OH)2·8H_2O溶液进行水热反应,利用X射线衍射(XRD)、扫描电子显微镜(SEM)、热重-差热分析(TG-DTA)和能谱分析(EDS)等手段对所得的样品进行表征分析。结果 K_2Ti_4O_9·3H_2O经过酸交换后可得到H_2Ti_4O_9·1.1H_2O晶体,该晶体剥离后得到二维纤维状H_2Ti_4O_9·nH_2O纳米带胶体。纳米带胶体与Ba(OH)2·8H_2O溶液进行水热反应后可得到110nm大小且有正方晶系的BaTiO3纳米陶瓷粉体,BaTiO_3纳米陶瓷粉体形貌规整,颗粒分布均匀,呈扁平的椭圆形块状。结论 K_2Ti_4O_9·3H_2O的离子交换反应可完全进行,交换后得到的层状化合物H_2Ti_4O_9·1.1H_2O在100℃时用乙二胺剥离效果最好,而且剥离的纳米带宽度仅有20nm。纳米带与Ba(OH)_2·8H_2O溶液基于溶解析出机制,反应12h后生成的BaTiO_3晶粒最小,结晶性最好。

Purposes-To prepare H2Ti4O9·nH2O nanobelts from K2Ti4O9·3H2O crystals, and investigate the structure and properties of the nanobelts in order to provide a novel target for the development of new functional materials. Methods-An ion exchange reaction was carried out between the K2Ti4O9·3H2O crystals and hydrochloric acid. A stripping reaction of the obtained sample was performed by using ethylenediamine and tetramethylammonium hydroxide solution, respectively. The obtained nanobelts colloid was solvothermally treated in Ba（OH）2·8H2O solution. The X-ray diffraction （XRD）, scanning electron microscopy （SEM）, thermogravimetric analysis （TG-DTA） , energy spectrum analysis （EDS） were utilized for the analysis of characterization. Results-A layered 2D H2Ti4O9·1. 1H2O crystal was firstly prepared by the ion exchange reaction with hydrochloric acid from K2Ti4O9·3H2O crystal. The different H2Ti4O9· nH2O nanobelts colloids can be prepared via a stripping reaction from the ethylenediamine and tetramethylammonium hydroxide solution, respectively. The H2Ti4O9·nH2O and all the obtained nanobelts show a 2D （two-dimensional） fiber-like. BaTiO3 crystals with a tetragonal symmetry and a size of 110 nm were prepared by solvothermal treatment of the obtained nanobelts colloids in Ba（OH）2·8H2O solution. The obtained BaTiO3nanoscale ceramic powders with uniform particle distribution present a regularly flat oval morphology. Conclusion-The ion exchange reaction of the KzTi409 - 3H20 crystal can be successfully performed. It is the best condition that the layered H2Ti4O9·1.1H2O crystal can be obtained by using ethylenedia- mine at 100℃, and the thickness of the H2Ti4O9·nH2O nanobelts is about 20 nm only. A dissolution and precipitation reactions were taken place between the nanobelts and Ba（OH）2·8H2O solution. The BaTiO3 crystals with a small size and high crystallinity can be obtained when the solvother- real reaction was carried out for 12 h.