Characterization of ZnO/rGO Nanocomposite and Its Application for Photocatalytic Degradation

Zinc oxide (ZnO) nanorods (NRs) with reduced graphene oxide (rGO) were successfully synthesized using a hydrothermal method with an additional spray coating. This paper focuses on the effect of rGO coating on charge transfer and interaction between ZnO and rGO that remarkably contributes to the enhancement of the electrical and optical properties of ZnO-based NRs. The synthesized ZnO/rGO nanocomposite was characterized using FESEM, PL spectroscopy and XPS. FESEM analysis results showed that the surface morphology of the synthesized NRs had a hexagonal rod structure covered with rGO layers on the tip of the rod. The Tauc Plot analysis revealed that the rGO layers reduced the bandgap of ZnO NRs from 3.25 eV to 3.17 eV, where the light absorption increased. The chemical composition, electronic state, and interactions between the elements in the ZnO NRs/rGO nanocomposites were investigated using XPS. The presence of oxygen species due to the rGO deposition layers is indicated by the shift of the peak position toward a greater binding energy. The hybridization of this semiconductor and graphene material reduced the bandgap and lowered the PL emission. Finally, the photocatalytic activity of ZnO NRs/rGO has been studied for methylene blue degradation via oxidation. The results showed that the photocatalytic reaction rate constant of ZnO NRs/rGO > pristine ZnO NRs.