Synthesis and characterization of rice grains like Nitrogen-doped TiO₂ nanostructures by electrospinning–photocatalysis

Rice grain-shaped Nitrogen-doped titanium dioxide (N–TiO₂) nano/mesostructures were fabricated through a combination of sol–gel and electrospinning methods. As-spun nanofibers were continuous and upon thermal treatment at 500°C for 1h in air, the continuous fibers break into rice grain-shaped TiO₂ nanostructures of average diameter 50–80nm. The nanostructures were characterized by spectroscopy, microscopy and powder X-ray diffraction. The rice grains consist of spherical particles of average diameter of ~18nm and with N doping, their average diameters decrease from ~18 to ~12nm. The presence of N in the TiO₂ lattice was confirmed by X-ray photoelectron spectroscopy (XPS). The band-gap of TiO₂ reduced from 3.19eV to 2.83eV upon increasing doping level of N from 0% to 5% (w/w), respectively. The N–TiO₂ rice grains showed an enhanced UV light-assisted photocatalysis compared to pure TiO₂ in the photodegradation of Alizarin Red S dye, an industrially important anthraquinone dye.