Highly efficient synthesis of graphene/MnO2 hybrids and their application for ultrafast oxidative decomposition of methylene blue

Abstract A highly efficient method has been reported to fabricate the reduced graphene oxide/MnO 2 (RGO/MnO 2 ) hybrid materials, a kind of catalysts for oxidative decomposition of methylene blue (MB). The pristine suspension of graphene oxide/manganese sulfate (GO/MnSO 4 ) produced by the modified Hummers method is in situ transformed into GO/MnO 2 composites in combination with KMnO 4 , and then further into RGO/MnO 2 composites by means of glucose-reduction. It is found that MnO 2 nanoparticles with the size of 20–30 nm are uniformly distributed in the structure of RGO. A series of composites with different mass ratios of RGO to MnO 2 has been proved superior catalytic activities, much higher than that of the bare MnO 2 for decomposition of MB dye in the presence of H 2 O 2 . Typically, 50 mL of MB (50 mg L −1 ) can be completely decolorized and nearly 66% mineralized at 50 °C in 5 min with 10 mg of the RGO/MnO 2 hybrid. According to the adsorption–oxidation–desorption mechanism, the high activity of RGO/MnO 2 composites for decomposition of MB is closely related to the positive synergistic effect of RGO and MnO 2 with the assistance of H 2 O 2 .