Synthesis And Properties Of Iron Oxides Microstructures

In this thesis, a-FeOOH microspheres, a-Fe2O3microspheres and ellipsoidal Fe2O3/FeOOH nanocomposites were successfully prepared via a liquid phase approach. The morphology, structure and properties of products were characterized by using SEM, TEM, XRD and UV-Vis spectra. The growth process was briefly discussed and experimental conditions were also studied.α-FeOOH urchin-like microspheres were prepared by a liquid phase method with FeC13·6H2O as iron source, polyvinyl pyrrolidone (PVP) as dispersant. The morphologies and microstructures of the product were characterized by using SEM and XRD. It was indicated that α-FeOOH urchin-like microspheres had diameters of about0.35μm with dispersibility. α-Fe2O3microspheres with hierarchical structures were prepared by calcining α-FeOOH. SEM and TEM indicated that α-Fe2O3sea urchin-like microspheres had the diameter of0.5pm. The photocatalytic activity of α-Fe2O3was evaluated via the photocatalytic decomposition of Congo red. The influence of experimental parameters on the photocatalytic performances of the product was investigated, such as pH value, catalyst addition, hydrogen peroxide (H2O2) concentration and temperature.microspheres were prepared through a hydrothermal method, with F3C13·6H2O and Fe(NO3)3·9H2O as mixed iron source, and PVP as dispersant. Then FeOOH coated on the Fe2O3layer in aqueous solution to form Fe2O3/FeOOH composite microspheres. According to the SEM images, the ellipsoidal Fe2O3/FeOOH nanocomposites with an average diameter of1to1.3μm and rough surface was observed. The photocatalytic activities of Fe2O3/FeOOH were evaluated through the photodegradation of Congo red.α-FeOOH sea urchin-like microspheres were prepared in aqueous solution with as iron source, urea as precipitant. According to the SEM images, the diameters of a-FeOOH were about500-700nm. The influence of experimental parameters on the morphology of the product was investigated, such as the amount of CO(NH2)2and NH4Fe(SO4)2·12H2O. The adsorption activities of α-FeOOH were evaluated through the adsorption of Congo red.