CeO2 nanorod/g-C3N4/N-rGO composite: enhanced visible-light-driven photocatalytic performance and the role of N-rGO as electronic transfer media

A novel CeO2 nanorod/g-C3N4/N-rGO ternary composite was synthesized using a simple ultrasonic-heat treatment method for application in the photocatalytic degradation of organic pollutants under the irradiation of visible light. This material shows superior photocatalytic activity compared with pure g-C3N4 and CeO2 nanorods, and the photodegradation rate of RhB is up to 2.1-fold higher than that of the g-C3N4/N-rGO (at the optimum content of 0.25 wt% N-rGO) catalyst when the content of CeO2 nanorods was 2 wt%. The enhancement of photocatalytic activity could be attributed to the synergistic effect among CeO2, g-C3N4 and N-rGO (serves as a conductive network), which was found to lead to more efficient separation of photogenerated electron-hole pairs, resulting in the effective photodegradation of organic pollutants. In addition, superoxide radical anions (O-center dot(2)-) and holes (h(+)) were considered as the main reactive species during the photodegradation process, and the ternary composite also exhibited preferable stability for the decomposition of RhB. This work provides an in-depth perspective for understanding the N-doped graphene-involved photocatalytic mechanism.