Hierarchical flower-like Fe3O4 and γ-Fe2O3 nanostructures: Synthesis, growth mechanism and photocatalytic properties

The present study describes a facile, economical and environment-friendly aqueous solution method of fabricating hierarchical flower-like Fe3O4 nanostructures under a moderate temperature (80 degrees C) and without the addition of any organic solvent or surfactant. The as-obtained products are characterized in detail. Control experiments demonstrate that the addition rate of reactants, H3PO4/FeSO4 molar ratio and reaction time influence the morphology of the products. Based on the experimental results, a possible growth mechanism for the formation of these hierarchical flower-like nanostructures is proposed. Well-defined flower-like gamma-Fe2O3 nanostructures are also successfully obtained by the thermal treatment of the Fe3O4 sample. These as-prepared flower-like Fe3O4 and gamma-Fe2O3 nanostructures are highly effective catalysts for the degradation of eriochrome black T (EBT) in aqueous solution with H2O2 as an oxidant and can be easily separated from the solution using an external magnetic field, exhibiting great potential in environmental cleanup applications.