Synthesis And Property Studies Of Three Dimensional Supertructured Metal Oxide Nanomaterials

Due to the unique physical and chemical properties,nanomaterials have great application potentials in many fields such as energy,environment,information,biology and medicine,which have attracted great research interests.Since the properties of materials depend greatly on the morphologies and assembly behaviors,it is believed that controllable synthesis of nanomaterials with different morphologies and assembly behaviors can further tune their chemical and physical properties and improve their performances in supercapacitor,lithium ion battery,optics,magnetism and so on.Therefore,it is of great importance in scientific researches and practical applications.In this thesis,we successfully synthesized a series of three dimensional superstructured metal oxides and their composites through facile methods.We explored reaction conditions to regulate their morphology and structure.The best reaction condition of integrate building blocks into superstructures and the effects of morphologies on materials properties were systematically investigated.1.Controllable synthesis of three dimensional honeycomb-like MnO2 superstructures composed of ultrathin nanosheets and their electrochemical performancesThree-dimensional(3D)superstructured materials own larger surface areas and more active sites,which may influence the properties of nanomaterials.Graphene-like MnO2 ultrathin nanosheets was synthesized by using carbon spheres to react with KMnO4 under mild conditions.By adjusting the reaction conditions,hollow structure and core-shell structured MnO2 were synthesized respectively.A novel 3D honeycomb-like MnO2 network was also achieved through assembling and rearranging carbon spheres.While changing the size of carbon spheres,ultrathin MnO2 nanosheets,hollow MnO2,core-shell MnO2 and 3D honeycomb-like MnO2 networks with different sizes were obtained.When testified as Li-ion battery anodes,3D honeycomb-like MnO2 networks display better performances than other of MnO2 structures.The supercapacitor test of 3D honeycomb-like MnO2 indicates that this material has great application potentials due to good performances with high specific capacities and excellent cyclabilities.2.One pot synthesis of novel three dimensional core-shell ?-Fe2O3 colloidosomesA novel core-shell ?-Fe2O3 colloidosomes were successfully synthesized via one-pot solvothermal approach for the first time.The growth mechanism and the property of the core-shell ?-Fe2O3 colloidsomes were investigated and discussed.The novel core-shell ?-Fe2O3 colloidosomes were assembled by ?-Fe2O3 nanoplates,which were composed of ?-Fe2O3 nanoparticles.?-Fe2O3 nanoplates are the building blocks of three dimensional superstructure.When testified as Li-ion battery anode,3D core-shell ?-Fe2O3 exhibited amazing specific capacities and excellent cyclabilities.3.Synthesis of hollow ?-Fe2O3,Fe3O4 and ?-Fe2O3 prisms via double solvent thermal methodHollow ?-Fe2O3 prism was synthesized using water and ethanol as reaction solvent media.The effect of experiment conditions on the formation of hollow?-Fe2O3 prisms were investigated and possible reaction mechanism was proposed.After calcining under different gas atmospheres,hollow ?-Fe2O3 prisms were successfully transferred to ?-Fe2O3 and Fe3O4 nanoprisms.Lithium ion battery properties indicated that samples can be used as promising materials for energy storage.4.Synthesis of three dimensional multifunctional flower-like Fe3O4/ZnO compositesTwo-dimensional sheet-like precursor and flower-like superstructured precursor Zn2[Fe(CN)6]were prepared using solvothermal method.Three dimensional multifunctional flower-like Fe3O4/ZnO composites can be obtained by calcining the precursor.The influence of temperature on the composition and morphology of products were investigated,which showed that low temperature was appropriate for Fe3O4/ZnO maintaining.Only iron was obtained when temperature went too high.The fluorescence and magnetism results indicated that the products possessed both photoluminescence properties and superparamagnetism property.Thus we anticipate that the composites have potential applications in biological separation,immunodetection,drug delivery and so on.