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.