Magnetically separable iron oxide nanostructures-TiO2 nanofibers hierarchical heterostructures: controlled fabrication and photocatalytic activity

Abstract

Novel hierarchical heterostructures of TiO2 nanofibers separately decorated with hematite (α-Fe2O3) or magnetite (Fe3O4) were prepared by combining the electrospinning technique and the hydrothermal method. Extensive characterizations of the resulting hierarchical heterostructures revealed that the secondary α-Fe2O3 or Fe3O4 nanostructures successfully grew on the surface of the primary TiO2 nanofibers substrates, thus integrating the magnetic and photocatalytic properties into the α-Fe2O3/TiO2 and Fe3O4/TiO2 hierarchical heterostructures. The component as well as morphology of the secondary α-Fe2O3 or Fe3O4 nanostructures could be further controlled by simply tuning the experimental parameters. Moreover, the magnetic properties and photocatalytic activities of the hierarchical heterostructures were systematically investigated. Electronic interactions between two semiconductors are the major contributing factor for the changed photoactivity. Most importantly, magnetic measurements showed that the Fe3O4/TiO2 hierarchical heterostructures were ferromagnetic and they could be separated and collected easily using a commercial magnet.