Cus nanocrystals/reduced graphene oxide (CuS NCs/rGO) composites were prepared by a facile one-pot-solvothermal reaction. In this solvothermal system, thioacetamide was found to perform the dual roles of sulphide source and reducing agent, resulting in the formation of CuS NCs and simultaneous reduction of graphene oxide (GO) sheets to rGO sheets. In addition, CuS NCs/rGO composites were further used as heterogeneous catalysts in the wet hydrogen peroxide catalytic oxidation process, with methylene blue as a model organic dye. The introduction of rGO to CuS NCs could effectively enhance the catalytic activity of CuS NCs, and the resultant CuS NCs/rGO composites with a starting GO amount of 5 wt% showed the highest catalytic activity. Furthermore, the CuS NCs/rGO composites showed high catalytic activity over abroad pH operation range from 3.0 to 11.0 under ambient conditions, and still retained 90% of the original catalytic activity after reuse in five cycles. (C) 2013 Elsevier B.V. All rights reserved.