Metal Oxide And Sulfide Nanomaterials: Synthesis And Characterization

Owing to unique physical properties, nanostructured metal oxides and sulfides have exhibited promising applications in many fields such as catalysis, sensing, optics, magnetics and batteries. Preparing novel nanostructures and investigating their general formation mechanism may be a solution to the precise control of their sizes, dimensionalities and properties. In this dissertation, systematic explorations have been carried out on new synthetic strategies of metal oxides and sulfides, including their formation mechanisms and novel properties.(1) Bismuth sulfide nanorods were synthesized in ionic liquid using bismuth nitrate and thiourea as precursor. The products were characterized by X-ray powder diffraction (XRD) , energy dispersive spectroscopy (EDS) , transmission electron microscope (TEM), high-resolution electron microscope (HRTEM) , selected area electron diffraction (SAED) and field-emission scanning electron microscope(FESEM) . The results show that well crystallized bismuth sulfide nanorods can be obtained by refluxing at 160℃in ionic liquid. The growth mechanism of nanorods has also been discussed.(2) Dumb-bell shaped ZnO with high purity and uniform size was synthesized by ultrasonic-assisted reflux method. SEM, TEM and XRD results showed that the reaction conditions, such as ultrasonic treatment, pH value of solution and additive ethylenediamine had played important roles on the formation of dumb-bell ZnO. UV-Vis and PL characterizations revealed that these dumb-bell ZnO had unique optical property and would have wider usage. The growth mechanism of dumb-bell ZnO was discussed. Furthermore, spindle ZnO sunk in the middle were also obtained by ultrasonic-assisted reflux method with the solvent of triethylene fouramine. The effect of reactant concentration, react time, sonication and reflux time on the morphology of ZnO product was investigated. It can be concluded that the cation of ethylenediamine and triethylene fouramine joint (0001) or (0001) crystal face ofZnO to form twinned crystalline first, and then result in different morphology of symmetric dumb-bell or spindle shapes due to the different growth rate of various crystal plane.(3) 3D CdS spherical nanostructures constructed with CdS nanorods were obtained by hydrothermal method in a binary solution system of water and triethylenetetramine. The morphology, structure, and phase composition of the as-prepared CdS products were examined by using various techniques (XRD, FESEM, TEM etc). It revealed that various 3D architectural structures of CdS in large quantities could be controlled by the additive thiourea and the volume ratio of the mixed solvents. It is suggested, during CdS growth, thiourea and triethylenetetramine might dominate the nucleation and oriented-assembly procedure respectively. Moreover, the effect of synthesized time on the morphology and PL properties of CdS has also been investigated.