It has been found that semiconductor nanocomposites have good photocatalytic behavior and can be used for the photodegradation of organic pollutants in water waste. ZnO, one of the eco-friendly semiconductor materials, was chosen to form a nanocomposite with graphene oxide. Graphene oxide in ZnO-based nanocomposites improves the photoactivity and photostability of ZnO. To prepare the graphene oxide, the Hummers method was used, then ZnO/GO nanocomposite was synthesized by hydrothermal method. The nanocomposites were annealed at different temperatures of 300 °C, 400 °C, and 500 °C. Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the structure of synthesized graphene oxide nanosheets. Structural characterization of the nanocomposites was investigated using X-ray diffraction, Transmission Electron Microscope (TEM), and Field Emission Scanning Electron Microscope (FE-SEM). X-ray diffraction patterns of nanocomposites demonstrate that the annealed sample at 300 °C has better crystallinity than the other samples and was used to investigate the photocatalytic process. Photocatalytic experiment of the ZnO/GO was carried out by degradation of methylene blue using a laboratory-made reactor in alkaline, acidic, and neutral solutions. Photodegradation results were revealed that the maximum percent degradation of 87% was achieved in the alkaline solution. تفاصيل المقالة