Enhanced Photocatalysis of Graphene and TiO2 Dual-Coupled Carbon Nanofibers Post-treated at Various Temperatures

Graphene and titanium dioxide (TiO2) were coupled to a conducting polymer substrate to generate graphene–TiO2 carbon nanofibers (GTCNs) using an electrospinning method with a post-thermal treatment process. The photocatalytic activities of GTCNs for the purification of selected toxic organic pollutants under visible-light illumination were higher than those of three reference photocatalysts (i.e., TiO2-, graphene-, and polyacrylonitrile-based carbon nanofibers). The photocatalytic activities of GTCNs increased with increasing treatment temperature from 300 to 400 °C and then decreased gradually with further increases to 500 and 600 °C, indicating that there is an optimum post-treatment temperature. The photocatalytic degradation efficiencies for the target pollutants over GTCNs post-treated at 400 °C under visible-light-emitting-diode (visible-LED) irradiation were lower than those obtained using a conventional daylight lamp. However, visible-LEDs were suggested as energy-potent photon sources for photocatalysis of gaseous toxic organic chemicals over GTCNs.