Electrochemical fabrication and reductive doping of electrochemically reduced graphene oxide decorated with TiO2 electrode with highly enhanced photoresponse under visible light

Abstract

The development of visible-light active TiO2 or TiO2-based composite materials has been extensively studied in recent years due to their wide range of applications in energy and photocatalysts. The present study reports a facile and environmentally friendly one-pot electrochemical method for the electrochemical fabrication and doping of the electrochemically reduced graphene oxide (ERGO) decorated with TiO2 nanoparticles. The electrochemical reductive doping of TiO2/ERGO composites was carried out in an aqueous solution of H2SO4, LiClO4, NaOH and KOH by a potential controlled electrochemical process. A significant shift of the absorption edge to a lower energy in the visible-light region for hydrogenated and doped TiO2/ERGO composites has been observed, which suggested that the bandgap energy of TiO2/ERGO was narrowed after electrochemical treatment. Photocurrent densities of H-, Li-, Na-and K-doped TiO2/ERGO composites were approximately 11, 12, 9 and 7 times higher than those of undoped TiO2/ERGO electrodes respectively, which indicated that the separation efficiency of photo-induced electrons and holes was improved dramatically after electrochemical hydrogenation and doping. This electrochemical reductive treatment appears to be an effective way to enhance the performance of photovoltaic devices in the visible range by improving the electrical conductivity and electron mobility.