Synthesis of TiO2 nanorod-decorated graphene sheets and their highly efficient photocatalytic activities under visible-light irradiation

The titanium dioxide (TiO2) nanorod-decorated graphene sheets photocatalysts with different TiO2 nanorods population have been synthesized by a simple non-hydrolytic sol-gel approach. Electron microscopy and X-ray diffraction analysis indicated that the TiO2 nanorods are well-dispersed and successfully anchored on the graphene sheet surface through the formation of covalent bonds between Ti and C atoms. The photocatalytic activities are evaluated in terms of the efficiencies of photodecomposition and adsorption of methylene blue (MB) in aqueous solution under visible-light irradiation. The as-synthesized TiO2 nanorod-decorated graphene sheets showed unprecedented photodecomposition efficiency compared to the pristine TiO2 nanorods and the commercial TiO2 (P-25, Degussa) under visible-light. It is believed that this predominant photocatalytic activity is due to the synergistic contribution of both a retarded charge recombination rate caused by a high electronic mobility of graphene and an increased surface area originated from nanometer-sized TiO2 nanorods. Furthermore, photoelectrochemical study is performed to give deep insights into the primary roles of graphene that determines the photocatalytic activity. (C) 2011 Elsevier B.V. All rights reserved.