Fabrication, structural morphology and photocatalytic activity of porous TiO2 nanofibres through combination of sol–gel, electrospinning and doping–removal techniques

Abstract

In this study, the TiO2/Al2O3 composite nanofibres were fabricated by electrospinning the composite spin dope containing both titanium(IV) n-butoxide and the precursor of Al2O3 (i.e. aluminium isopropoxide); thereafter, the Al2O3 component would then be removed via chemical etching with NaOH aqueous solution, resulting in the formation of nanoscale pores throughout the (final) TiO2 nanofibres. The morphology, crystalline structure, specific surface area and photocatalytic degradation properties on Reactive Orange KGN and Reactive Brilliant Blue KN-R of the porous TiO2 nanofibres were investigated by field emission SEM, X-ray diffractometry, high resolution transmission electron microscopy, Brunauer–Emmett–Teller (BET) surface area analyser and ultraviolet–visible spectrometer respectively. The results indicated that the fabricated porous TiO2 nanofibres possessed ribbon shaped morphology with homogeneous fibre diameters. The porous TiO2 nanofibres were polycrystalline and processed anatase phased TiO2 with a crystallinity of ∼91%. The BET specific surface area of porous TiO2 nanofibres was ∼106·5 m2 g−1, which was higher than that of solid TiO2 nanofibres (∼15·2 m2 g−1). The porous TiO2 nanofibres could eliminate ∼64% of the Reactive Orange KGN dye within 160 min and ∼65% of Reactive Brilliant Blue KN-R dye within 200 min, which is attributed to its high photocatalytic degradation efficiency.