Preparation of titanium dioxide nanoparticles immobilized on polyacrylonitrile nanofibres for the photodegradation of methyl orange

Abstract

Herein, we describe the synthesis of titanium dioxide (TiO2) nanoparticles by the hydrolysis and condensation of titanium tetrachloride. The resulting nanoparticles were immobilized on polyacrylonitrile (PAN) based nanofibres by an electrospinning technique in order to allow simple isolation and reuse of titania semiconductor photocatalyst. The composite nanofibres were heat treated to convert the polymer nanofibres to carbon nanofibres and to convert amorphous TiO2 to crystalline TiO2. X-ray diffraction (XRD) analysis showed that the rutile phase was the major phase and the equatorial peaks of PAN disappeared after heat treatment at 600∘ C. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analysis confirmed that some TiO2 nanoparticles were encapsulated whereas some were surface residing on the electrospun nanofibres. The TiO2 nanoparticles were found to lower the cyclization temperature of PAN as indicated by differential scanning colorimetry (DSC) and differential thermal analysis (DTA). Photocatalytic studies on the degradation of methyl orange dye under UV light irradiation showed that composite nanofibres were capable of degrading organic contaminants in water. The carbon nanofibres with surface residing titanium dioxide nanoparticles (TiO2/CNF-SR) showed the highest photocatalytic activity (59.35% after 210 minutes) due to direct contact between the TiO2 photocatalyst and methyl orange