水热条件下合成的γ-AlOOH纳米棒的形貌及形成机制

Morphologies ofγ-AlOOH Nanorods and Formation Mechanism at Hydrothermal Conditions

研究了以1mol/L的AlCl3为铝源,1mol/L的NaOH为沉淀剂,在不同水热条件下合成γ-AlOOH纳米棒,用X射线衍射仪(XRD)和热场发射透射电子显微镜(TEM)对合成样品进行表征。结果表明:不同水热条件下合成的样品的物相均为γ-AlOOH;当水热反应温度为150℃时,随反应时间延长和pH增大,棒状γ-AlOOH长径比增大;当水热反应时间为48h、pH=9时,随反应温度升高,合成的棒状γ-AlOOH的长径比增大,在180℃时获得径向尺寸小于10nm的γ-AlOOH纳米棒;但随反应温度进一步升高,γ-AlOOH长径比显著变小;反应温度对合成γ-AlOOH纳米棒的影响具有两面性。探讨了不同水热条件下γ-AlOOH纳米棒的形成机制。

γ-AlOOH nanorods were synthesized using 1 mol/L AlCl3 solution as aluminium source and 1 mol/L NaOH solution as precipitant under hydrothermal conditions. The samples prepared were characterized by X-ray diffraction（XRD） and field-emission transmission electron microscope（TEM）. XRD analysis shows that the phases of the samples obtained under the different conditions are γ- AlOOH. TEM analysis confirms that the increasing of reaction time and pH are in favour of the increasing of slenderness ratio of ）＇-A1OOH rods when reaction temperature is 150 ℃. The higher reaction temperature is remarkably propitious to extend the slenderness ratio of γ-AlOOH nanorods when reaction time and pH are 48 h and 9,respectively. And γ-AlOOH nanorods with about 10 nm in the radial direction are successfully prepared when reaction temperature is 180 ℃. However,with the further rise of reaction temperature,the slenderness ratio of γ-AlOOH nanorods decreased markedly. Therefore,there are two sides influence of reaction temperature on the morphologies of γ-AlOOH nanorods. Finally,the formation mechanism of γ-AlOOH nanorods was discussed.