Synthesis And Characterization Of IV/V Metal Oxides Nanomaterials

Nanostructures have attracted great interests due to their novel physical,chemical, and catalysis properties as well as the potential applications in nanodevices. Hydrothermal method has been widely employed to prepare nanomaterials and nanostructures due to its advantage of low synthesis temperature,simplicity, cost-effectiveness,high crystallization,environmental friendliness and high yield.In this dissertationα-Sb₂O₄ nanorods and SnO₂ woolsphere-like microstructures were synthesized by hydrothermal method;based on XRD and SEM of products which were obtained at different times and temperatures,the growth mechanism of Pb₅S₂I₆ nest-like microtubules was investigated comprehensively.1.α-Sb₂O₄nanorods with diameter of 50～150 nm and length of 100～300 nm have been successfully synthesized by a hydrothermal method using SbCl₃ and I₂ as reaction reagents.The obtained sample is characterized by X-ray diffraction, transmission electron microscopy,high-resolution transmission electron microscopy, and selected-area electron diffraction.The results confirm that the product is pure single-crystallineα-Sb₂O₄ nanorods with few dislocations and defects.The vibrational property of the nanorods is investigated by Raman spectroscopy.Raman spectrum ofα-Sb₂O₄ nanorods has a small red shifts compared with that of the bulkα-Sb₂O₄ powders.A possible growth mechanism ofα-Sb₂O₄ nanorods is proposed as three stages:the hydrolyzation of SbCl₃ under strong acid condition,the oxidation of Sb₄O₅Cl₂ and the growth ofα-Sb₂O₄ nanorods with the aid of iodine transport.2.Novel SnO₂ woolsphere-like microstructures have been successfully prepared by a simply mild hydrothermal method based on the reaction between helix-like tin wire and HNO₃ at 200℃.X-ray diffraction(XRD) and scanning electron microscopy (SEM) are used to characterize the microstructures.The SnO₂ woolsphere-like microstructures show a red shift in Raman spectrum compared with bulk materials. The woolsphere-like microstructures of SnO₂ have strong PL emission,suggesting that the mircostructures are potential to be used for optoelectronic devices.3.We report the investigation on the growth mechanism of Pb₅S₂I₆ bird-nest like microtubules,which were synthesized by hydrothermal method at 150℃.X-ray diffraction(XRD) characterizes that the component and corresponding phases of samples obtained in different stages.Scanning electron microscopy(SEM) depicts that the morphology evolution of products.The microtubule growth process has three stages:the rolling of PbI₂ sheets;formation of Pb₅S₂I₆ microrods;developing Pb₅S₂I₆ microtubules.We propose that the Pb₅S₂I₆ bird-nest like microtubules growth mechanism to be a rolling-template-induced concentration depletion growth mechanism based on the characterization results.