Preparation And Characterization Of Iron Oxide Composite Micro(nano)-structures

In this paper,Fe3Oa microspheres,?-Fe2O3 microsphere,spherical Fe3O4/Fe2O3 nanocomposites,ellipsoidal Fe2O3/SiO2/Ni(OH)2 nanocomposites,spherical Fe2O3/CeO2 nanocomposites and ellipsoidal Fe2O3/CeO2/Ni(OH)2 were successfully prepared by a simple hydrothermal method at ambient temperature and pressure.The morphology and properties of the products were characterized by means of SEM,XRD,vibrating sample magnetometer,the formation mechanism was briefly discussed and the morphology of the as-synthesized nanoparticles could be controlled by changing the amount of CO(NH2)2.1.The preparation and characterization of Fe3O4/Fe2O3 core-shell structureFe3O4 microspheres were prepared by a simple hydrothermal method with polyvinyl pyrrolidone(PVP)as structure directing reagent.Then Fe3O4 nanoparticles were used as a template,Fe3O4/Fe2O3 core-shell structure were prepared by a simple hydrothermal method on the surface of Fe3O4.Scanning electron microscopy(SEM)investigation indicated that Fe3O4/Fe2O3 core-shell structure were constructed with assemble of Fe2O3 nanoparticles.The magnetic hysteresis loop of Fe3O4/Fe2O3 shows the sample had superparamagnetism.Electrochemical analysis test demonstrate the sample had good cycle performance.The amount of FeCl3·6H2O was briefly discussed and the possible formation mechanism was proposed.These Fe3O4/Fe2O3 core-shell structure may have potential application in fabricating sensors for chemical and biochemical analysis.2.The preparation and characterization of Fe2O3/SiO2/Ni(OH)2 nanocompositesEllipsoidal Fe2O3/SiO2/Ni(OH)2 nanocomposites were prepared via a hydrothermal process with PVP as surfactant.Scanning electron microscopy(SEM)investigation indicated that the surface of Fe2O3/SiO2/Ni(OH)2 nanocomposites were constructed with Ni(OH)2 nanosheets which were further built up with assembled Ni(OH)2 nanoparticles.The diameters of sample were about 1.5 ?m.The possible formation mechanism was proposed.3.The preparation and characterization of Fe2O3/CeO2 and Fe2O3/CeO2/Ni(OH)2 nanocompositesEllipsoidal Fe2O3/CeO2 nanocomposites were prepared by reaction of NiSO4·6H20.Ce(NH4)2(NO3)6 and urea via a simple hydrothermal process with PVP as capping reagent.The influence of experimental parameters,such as the amount of CO(NH2)2 on the morphology of the product was investigated and the growth mechanism was briefly discussed.The sample shows uniform dispersion and large particle size when increasing urea content.