Hydrothermal Synthesis And Properties Of Hierarchical Micro-structures Transition Metal Oxides

The hierarchical structure is composed of interlaced nano lamellar which is like sea urchins.Over the past decades,the hierarchical transition metal oxides have attracted much attention due to their extensive applications in catalysis,sensing,adsorption,energy and other fields.In this thesis,the synthesis method of the three parts of this thesis is to obtain the target product with hierarchical morphology through the template method,doping method and compound method respectively on the the basis of the hydrothermal method.In this thesis,the hierarchical manganese dioxide?MnO₂?,the hierarchical Cu doped ZnO and the hierarchical CuO-CeO₂ complexes were successfully synthesized by simple hydrothermal method.Species.X-ray diffraction?XRD?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X-ray photoelectron spectroscopy?XPS?,Fourier transform infrared spectroscopy?FTIR?,Thermogravimetric analyzer?TG?and other instruments were used to characterized these three materials,and also studied their applications in supercapacitor,optics,adsorption and so on.The details are as follows:1?Hydrothermal synthesis of the hierarchical manganese dioxide and its supercapacitor properties.We used different manganese carbonate as templates,and potassium permanganate as the etchant with one-step hydrothermal route to obtain the target products.The morphology,composition and structure of the synthesized products were characterized by SEM,FTIR and XRD.The specific surface area and the properties of supercapacitor were tested.The results show that the two kinds of different template synthesis of manganese dioxide has different morphological structure,respectively,bean dregs and hierarchical.And the hierarchical manganese dioxide BET surface area is little larger than the bean dregs of manganese dioxide,and it's has good capacitance properties and good cycling performance.2.Hydrothermal Synthesis of Copper doped Zinc Oxide and it's Properties.The target products were synthesized by hydrothermal-calcination method usingzinc nitrate as the main raw material,urea as the precipitant and polyvinylpyrrolidone?PVP?as the surfactant.The morphology,composition and structure of the synthesized products were characterized by SEM,XRD,XPS and TG.The optical properties and specific surface area of the target products were measured.The results show that the incorporation of copper elements increases the specific surface area of zinc oxide;the range of light absorption increases;the fluorescence intensity is enhanced.In the experiment,the quality of copper nitrate doping was changed,and the influence of the incorporation of copper element on the morphology of zinc oxide was studied.3.Hydrothermal Synthesis and Adsorption Properties of the hierarchical CuO-CeO₂ Composites.The CuO-CeO₂ composites material with the hierarchical structure were synthesized by hydrothermal method using cerium nitrate and copper sulfate as the main raw materials and urea as the precipitant in the mixed solvent of water and ethylene glycol.Under the same conditions for membership of the single metal salt synthesised monomer copper oxide and cerium oxide.The morphology,composition and structure of the composites and monomer were characterized by SEM,TEM,XRD,XPS,TG.The rate processs of adsorption Methyl Blue and Congo Red on the copper oxide,cerium oxide and composite materials were studied.The results show that the composites of CuO-CeO₂ shows better adsorption performance than monomer.