Flexible and thermally stable SiO2–TiO2 composite micro fibers with hierarchical nano-heterostructure

Abstract

TiO₂-based micro/nano fibres with secondary hierarchical structure have been extensively studied concerning a wide range of applications. However, simultaneous optimization of the flexibility and thermal stability of these materials still remains a big challenge. In this investigation, the successful fabrication and characterization of TiO₂–SiO₂ composite micron fibers with both high flexibility and excellent thermal stability are reported. Electrospun flexible SiO₂ fibers were used as the scaffold for supporting TiO₂ nanostructures. Three distinguished layers of porous SiO₂, anatase TiO₂ nanoparticle and rutile TiO₂ nanorods were muffled over the SiO₂ fibers stepwise, forming a unique core@multi-shell architecture with hierarchical structure. Such elaborately designed core@multi-shell TiO₂–SiO₂ fibers present high flexibility, excellent thermal stability, large specific surface area and high porosity. Moreover, they are easy to be patterned into nonwoven film with hierarchically porous structure, which is promising for many applications. We evaluate the water purification performance of the TiO₂–SiO₂ nonwoven film with Rhodamine B as a model organic pollutant. Efficient removal of Rhodamine B from water was implemented via simple filtration under UV irradiation, and regeneration of the photocatalytic functionality of the film from organic contamination was conveniently realized merely through calcination.