TiO2 nanofibers resembling ‘yellow bristle grass’ in morphology by a soft chemical transformation

Abstract

We synthesized a uniquely shaped one-dimensional (1-D) TiO₂ nanostructure having the morphology of yellow bristle grass with high surface area by the titanate route under mild reaction conditions. The electrospun TiO₂–SiO₂ composite nanofibers upon treatment with concentrated NaOH at 80 °C under ambient pressure for 24 h resulted in sodium titanate (Na₂Ti₃O₇) nanostructures. The Na₂Ti₃O₇ nanostructures have an overall 1-D fibrous morphology but the highly porous fiber surfaces were decorated with layered thorn-like features (a morphology resembling that of yellow bristle grass) resulting in high surface area (113 m² g⁻¹) and porosity. The Na₂Ti₃O₇ nanostructures were converted into TiO₂ nanostructures of the same morphology by acidification (0.1 N HCl) followed by low temperature sintering (110 °C) processes. Dye-sensitized solar cells (DSCs) constructed out of the material (cells of area 0.20 cm² and thickness 12 μm) showed a power conversion efficiency (η) of 8.02% in comparison with commercial P-25 TiO₂ (η = 6.1%).