Preparation and photocatalytic properties of graphene/TiO2 nanotube arrays photoelectrodes

Graphene/TiO2 Nanotube Arrays (GR/TNAs) photoelectrodes were fabricated by in-situ anodization and electro-deposition method. The surface morphology, structure, photoluminescence spectra (PL), and photocatalytic activity of the samples were investigated. The as-prepared graphene/TNAs (GR/TNAs) photoelectrodes showed significant improvement in the separation of photogenerated carriers and excellent photocatalytic stability. The effects of irradiation time, initial concentration, ionic strength and bias potential on the removal of rhodamine B (Rh.B) by TNAs and GR/TNAs were studied. Results showed that degradation rate of Rh.B for GR/TNAs photoelectrodes reached 75% after 60 min illumination at pH of 6.0. The GR/TNAs exhibited significantly enhanced photocatalytic activity compared to unmodified TNAs. When the bias potential was applied, Rh.B degradation rate increased to 90% at 0.5 V. NO3-, Ca2+ and Mg2+ in the solution promoted the degradation of Rh.B, while SO42-, Cl- and F- suppressed the removal rate. (C) 2014 Elsevier B.V. All rights reserved.