Sol–gel growth of titania from electrospun polyacrylonitrile nanofibres

In this paper we report on the development of TiO 2 surface-residing electrospun nanofibres with controllable density of TiO 2 on the support fibre surface by means of an electrospinning technique and a sol–gel process. The TiO 2 precursor/PAN composite nanofibres were synthesized by electrospinning a polyacrylonitrile (PAN) solution containing TiO 2 precursors. Subsequently, an immersion of the electrospun composite nanofibres in deionized water led to the hydrolysis of the TiO 2 precursors. SEM, TEM and XRD pattern analyses demonstrated that TiO 2 was formed and resided on the nanofibre surface. On further calcining the hydrolysed nanofibres in air at 300 °C, TiO 2 could be conveniently converted into anatase without essentially changing the morphology of the hydrolysed nanofibres. Furthermore, surface photovoltage spectroscopy (SPS) confirmed that the TiO 2 surface-residing nanofibre nonwovens had a strong SPS response. It can be attributed that the surface residence of TiO 2 permits the transfer of the photogenerated electron originating from TiO 2 to ITO electrodes. Potential applications of the TiO 2 surface-residing nanofibres include filters, catalysis films and environmental pollution remediation films.