| Because of unique physical and chemical properties, SnO2micro-nano spheres and their derivatives have been widely studied in fields of energy and environment in recent years. Their application performance is closely related to the preparation methods, composite composition, particle size, surface morphology and other synthesis factors. Therefore, how to prepare highly dispersed, size-controlled micro-nano SnO2composite structure is one of the topics worthy of further study. In this thesis, we successfully produce structural stability, highly dispersed SnO2micro-nano hollow spheres and carbon-coated SnO2composite hollow spheres (SnO2/C) by using hard templating methods. Meanwhile, we also investigate their adsorption and electrochemical properties. Conclusions are as follows:(1) Polystyrene (PS) microspheres synthesis by emulsion polymerization process. The styrene monomers are anaerobic polymerized in different ratio of water and ethanol solvent to get PS microspheres with variable size in diameter. After separation, the obtained PS spheres were treated by sulfonation using fume acid. The sulfonation PS was chosen as template microspheres for later coating reaction. It shows that by changing the synthesis conditions334-820nm PS micro-nano spheres which have uniform size and monodispersive could be obtained. The morphology and particle size of sulfonated PS microspheres are essentially unchanged characterized by SEM. IR spectroscopy shows that successful sulfonation with-SO3H group of the microspheres will be applied to the subsequent composite structure.(2) Preparation of SnO2micro/nano hollow spheres and SnO2nanocomposite hollow microspheres was conducted by hard templating methods. We use sulfonated PS microspheres (PSS) as template and anion and cation electrostatic adsorption to combine Sn+from the precursor SnSO4with-SO3H on the template surface. By Sn2+hydrolysis in ethanol-aqueous medium, we get core-shell composite structure of PSS/SnO2. After high-temperature calcination treatment for removal of PSS, the PSS/SnO2changed into SnO2micro-nano hollow spheres. With the further carbonization of the PSS/SnO2/glucose composite microspheres, SnO2/C composite hollow spheres were fabricated. In order to obtain composite micro-nano spheres which have smooth surface, compact structure and well-controlled coating thickness, we explored the important roles of the concentration of the precursor, the amount of surfactant, the different of reaction time and the template selection in these two micro-nano spheres formation processing. With the results of SEM, TEM, XRD, IR, TGA, H2-TPR and BET technology, the redox characteristics of the structure, specific surface area and the core-shell structure formation mechanism were discussed.(3) Application of composite micro-nano spheres in sewage treatment of dye solution. SnO2micro-nano hollow spheres and SnO2/C composite hollow spheres are adsorbent materials which can adsorb Basic fuchsin Methylene blue and Congo red solution. SnO2micro-nano hollow spheres can be simulated adsorption process of Congo red solution under acidic conditions. This process is regenerated and the regeneration performance is stability. The adsorption properties of SnO2/C composite hollow spheres are improved than SnO2micro-nano hollow spheres and they could be widely applied to sewage treatment.(4) Composite microspheres are applied to the capacitor. CV and charge-discharge properties of SnO2micro-nano hollow spheres and SnO2/C composite hollow spheres are investigated, respectively, in the foam nickel electrode under alkaline condition. The specific capacitance of SnO2/C composite hollowspheres can reach43.30F·g-1and show excellent charge-discharge behavior. |
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