Chemical approaches to the reduction of graphene oxide (GO) for large-scale production of reduced graphene oxide (RGO) sheets have become a reality, speeding up the availability of graphene. In this work, an RGO-TiO2-ZnO composite was synthesized through the hydrothermal reduction of GO in a deionized (DI) water solution containing TiO2 and ZnO precursors at 180 degrees C. Morphological and structural characterizations using several techniques are reported. The photocatalytic activity of the synthesized RGO-TiO2-ZnO composite is approximately 63% at 120 min under 100W UV irradiation, which is much higher than that of pure ZnO (11%). The enhanced properties are described in terms of increased light absorption intensity and the reduction of electron-hole pair recombination in the composite owing to the stepwise energy level structure in the composite. (C) 2014 Elsevier B.V. All rights reserved.