Facile Fabrication of ZnO Nanorods Modified with RGO for Enhanced Photodecomposition of Dyes

Abstract Reduced graphene oxide/zinc oxide-rods composites (RGO/ZnO) were prepared through simple hydrothermal treatment of graphene oxide /zinc peroxide (GO/ZnO2) microspheres. The results of TEM, SEM and XRD show that the rod-like structure ZnO were successfully transformed from ZnO2 microspheres after high temperature treatment and combine well with GO. The synthesized RGO/ZnO-rods composites showed better photocatalytic performance as compared to pure ZnO2, ZnO and GO/ZnO2 under UV and visible-light irradiation. The improved photocatalytic performance of RGO/ZnO-rods composites was attributed to the uniform structure and excellent electrical conductivity of RGO, which could reduce the combination rate of the photo electron-hole pairs. After 5 consecutive cycles of testing, the RGO/ZnO-rods composites still have excellent photocatalytic performance, which was found to depend on ZnO content and NaCl concentration but was not affected by pH. The result of ESR experiment confirmed that the superoxide radicals (O2.-) and hydroxyl radicals (·OH) play an important role in the decolorization process of MO. Additionally, the kinetic rate constant (K) and mechanism of RGO/ZnO-rods composites had also been studied.