Shape-controlled Synthesis And Photocatalytic Activity Of Iron Oxides With Multiple Morphologies

Iron oxides are one of the most extensive and abundant Compounds in the nature, theyare located in every corner of the earth, such as soil, rocks, water, vivo and so on. The speciesof iron oxides are various, which mainly involve （α-，β-，γ-，ε-）Fe₂O₃，（α-，β-，γ-，δ-）FeOOH，Fe₃O₄and Fe（OH）₃. Iron oxides with different chemical stability can be transformedinto each other. As the important industry materials, iron oxides have been widely used invarious fields, such as catalysis, pigments, gas sensor, magnetic recording material andbiomedicine. With the development of science and society, higher requirements are putforward in the aspect of quality, production technology and process. Thus, the controlledfabrication of iron oxides have attracted more and more researchers,attention.In this paper, controlled synthesis of iron oxides nano-materials with novel morphology,high degree of crystallization and catalytic activity were obtained through colloid-coagulationmethod in order to change the water pollution in current society.The main contents are as follows:（1） The controlled synthesis of α-Fe₂O₃and photocatalytic activity.In the experiment, α-Fe₂O₃nano-materials with high degree of crystallization anduniformly dispersed morphology are prepared through a novel, mild，simple and green route.Besides, the concentration of urea and time of water bath are discussed.Urea play the role of structural adjustment and morphology control after nucleation ofFe（OH）₃colloid. The α-Fe₂O₃have a strong absorption in the range of visible light with bandgap of1.90eV, this lay the foundation for sunlight photocatalysis.Photocatalytic optimal conditions: UV irradiation, concentration of H2O20.075mmol/L,initial pH3-4, concentration of photocatalyst40mg/L. However, sunlight has characteristicsof inexhaustible supply and green with well photo degradation of methylene blue solutionabout two hours. Compared with other light source, sunlight make it possible forpopularization and application.（2） The assemble of α-Fe₂O₃particles and photocatalytic activity.The supported α-Fe₂O₃/PS sphere are prepared, using the carrier of polystyrene sphere through electrostatic attraction. Not only the supported α-Fe₂O₃/PS sphere remain highcatalytic activity of α-Fe₂O₃particles, but polystyrene spheres have the advantage of low cost,wide application, recycling, practicability. Thus, the recycling of supported α-Fe₂O₃/PS spherehas been well improved.（3） The controlled synthesis of β-FeOOH and photocatalytic activity.The β-FeOOH particles with morphology of bundle, needle and floccules, are controlledsynthesized by adding different mass of sugar（glucose, soluble starch and ganoderma lucidumpolysaccharides）. The different β-FeOOH with high crystallization degree show wellphotocatalytic activity in the irradiation of sunlight. Besides, the function of sugar is studied.When the quality of sugar is less, the structure and morphology of iron oxides is adjusted bysugar; When the quality of sugar is improved, sugar will restrain phase change of β-FeOOH toα-Fe₂O₃.