Facile preparation of magnetic γ-Fe2O3/TiO2 Janus hollow bowls with efficient visible-light photocatalytic activities by asymmetric shrinkage

Abstract

In this paper, on the basis of a simple side-by-side co-electrospray procedure with a subsequent non-equilibrium calcination process, we have for the first time developed an asymmetric shrinkage approach for the fabrication of magnetic γ-Fe₂O₃/TiO₂ Janus hollow bowls (JHBs) by constructing a precursor solution pair with different gelation rates during the solvents evaporation process. The formation mechanisms of the bowl-shapes as well as the hollow interiors are proposed and confirmed. The as-obtained γ-Fe₂O₃/TiO₂ JHBs have a transition layer of Fe³⁺-doped-TiO₂ between the γ-Fe₂O₃ and TiO₂ phases, and show an efficient visible-light photocatalytic activity and convenient magnetic separation for water purification because of the unique structure and morphology as well as the fine magnetic properties. Moreover, the method reported here can be readily extended to the fabrication of other bi-, tri- and multi-component metal oxides hollow particles with asymmetric shapes. Due to the interesting bowl-shaped hollow nanostructure, the as-prepared γ-Fe₂O₃/TiO₂ JHBs are expected to have a number of applications that involve drug delivery, micro-/nano-motors, microcontainers, microreactors, sensors, and so forth.