The synergistic mechanism of free radicals between graphene oxide (GO) and hydrogen peroxide (H2O2) under visible light Graphene oxide (GO) is a promising metal-free photocatalyst for the degradation of organic pollutants. In particular, GO and H2O2 exhibit a synergistic effect that significantly enhances the degradation efficiency of organic pollutants. However, the mechanism of reactive oxygen species (ROS) generation and transformation in the GO and H2O2 system (GO/H2O2) has not been reported.