Nanocables composed of anatase nanofibers wrapped in UV-light reduced graphene oxide and their enhancement of photoinduced electron transfer in photoanodes

Abstract

This paper reports a facile method for fabricating a new nanocable structure consisting of reduced graphene oxide (RGO) wrapped anatase TiO₂ nanofibers by UV-light photocatalytic reduction. The nanocable was prepared by injecting 0.8 g L⁻¹ aqueous graphene oxide colloid into 0.8 g L⁻¹ electrospun TiO₂ nanofibers in ethanol, followed by a mild UV light irradiation for 20 h. The conformal wrapping of RGO is a result of noncovalent interactions (van der Waals and electrostatics). The RGO walls of the nanocables exhibited a uniform thickness of ∼5 nm. Half of the oxygen groups were removed and the partially reduced RGO was favored to be well dispersed in water. The invariability of the I_D/I_G ratio of the D to G bands in Raman spectra proposed the presence of a “defect-repair” process in the reduction. We further demonstrated the enhancement of photoinduced electron transfer and depression of electron combination by integrating the RGO/TiO₂ nanocables into TiO₂ photoanodes, proving our nanocables are good candidates for photovoltaic devices.