Photocatalytic degradation of methylene blue was implemented as a laboratory experiment by the undergraduate students majoring in chemical education using graphene (GR)/TiO[subscript 2] as a catalyst. These chemistry preservice teachers synthesized a GR/TiO[subscript 2] composite and used it to degrade wastewater containing methylene blue under simulated sunlight irradiation. The main objectives of this experiment are to introduce cutting-edge science to preservice teachers, train their ability to comprehensively use multidisciplinary science or techniques, and teach the concept of green chemistry and environmental protection. By simplifying the experimental procedures, this experiment may be introduced into chemistry classrooms as a laboratory experiment or demonstration at middle schools and even primary schools because of the limited time required for complete degradation of methylene blue.