Room-temperature fabrication of anatase TiO2 submicrospheres with nanothornlike shell for photocatalytic degradation of methylene blue

A novel anatase TiO2 submicrosphere with a rough shell of nanothorns was fabricated at room temperature by a chemical solution deposition technique using TiF4. The resulting sample was characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen sorption measurements and Fourier transform infrared (FT-IR) spectrometry. The fabricated TiO2 submicrospheres had a uniform size of about 500 nm. The shell of TiO2 submicrospheres was covered by nanorods of 20–30 nm in diameter. These nanorods consisted of nanothorns which were 5–8 nm in diameter and about 20 nm in length. The unique rough shell resulted in higher absorbance because the light can have multiple reflections among nanorods and nanothorns. The TiO2 submicrospheres exhibited similar performance as commercial nanoparticle TiO2 (P25) on photocatalytic oxidation of methylene blue (MB). The TiO2 submicrospheres were completely separated from treated water by membrane filtration without serious membrane fouling compared to P25. The durability test showed that the mechanical strength and photocatalytic activity are stable enough for multiple recycling. This environmentally friendly and energy efficient method may pave way for new photocatalyst design.