Crystalline phase transformation of electrospinning TiO₂ nanofibres carried out by high temperature annealing

In this work reports the crystalline phase transformation of electrospinning TiO₂ nanofibres by annealing at high temperatures. The nanofibres chemical stoichiometry was determined by Energy-dispersive X-ray spectroscopy (EDS), which allowed find that the TiO₂ crystal phase transformation is caused by oxygen vacancy generation. The TiO₂ nanofibres diameter varied from 137.0 to 115.3 nm in the temperature range of 100–1000 °C, which was estimated by Scanning Electron Microscopy. The TiO₂ nanofibres structural transformation from pure anatase to pure rutile structures, including the quasi-amorphous and anatase-rutile mixed phases has been confirmed by Raman scattering and X-ray diffraction. The Raman spectroscopy exhibits the anomalous behaviour for band broadening and shifting of Raman bands with increasing crystallite size that form the nanofibres. By X-ray diffraction was found that the nanofibres crystalline phases present as preferential growth direction (101) for anatase and (110) for rutile.