50%BiOCl/BiOl/reduced graphene oxide (50%BiOCl/BiOl/rGO) composite photocatalyst was synthesized successfully by a facile one-step solvothermal route in this work. Reduction of graphene oxide (GO) took place in the process of solvothermal reaction and a new Bi-C bond between rGO and 50%BiOCl/BiOl was formed. The introduction of rGO affected the morphology of 50%BiOCl/BiOl, resulting in the transformation of 50%BiOCl/BiOl from solid microspheres to hollow microspheres. Both the introduction of rGO and formation of 50%BiOCl/BiOl hollow microspheres can facilitate the light absorption. The strong interaction between 50%BiOCl/BiOl and rGO and the electrical conductivity of rGO greatly improved the effective separation of photogenerated carriers. Hence, GOB-5 demonstrated the highest photocatalytic activity which was over twice of the pristine 50%BiOCl/BiOl in the presence of visible light. Mechanism study revealed that 50%BiOCl/BiOl generated electrons and holes in the presence of visible light, and holes together with center dot O-2(-) generated from reduction of O-2 by electrons degraded the pollutant directly. Overall, this work provides an excellent reference to the synthesis of chemically bonded BiOX/BiOY (X, Y = Cl, Br, I)/rGO nanocomposite and helps to promote their applications in environmental protection and photoelectric conversion. (C) 2017 Elsevier B.V. All rights reserved.