Synthesis of novel α-Fe₂O₃-Bi₂S₃-Gr for efficient photocatalytic degradation of environmental pollutants under visible-LED light irradiation

α-Fe₂O₃-Bi₂S₃ nanorods was successfully synthesized via a hydrothermal route with incorporation of graphene obtained from the pyrolysis of alginate, and was employed as a catalyst of the degradation of benzotriazole (BTA) in a photo-Fenton process. Due to the unique combination of graphene and the binary α-Fe₂O₃-Bi₂S₃ nanorod, the sample with 3 wt% graphene loading shows a high catalytic activity of 98% of BTA conversion under LED-visible light. The quenched free radicals are detected with an Electron Spin Resonance (ESR) technique, and the results indicate that hydroxyl radical ^•OH contributed to the BTA degradation reaction. A mechanism is proposed. Furthermore, the reusability of the catalyst was examined and the catalyst showed high activity over four cyclic runs.