▎ 摘　　要

Textile industries extensively use colorants, such as methylene blue, and if disposed off untreated, they contaminate the effluent streams, causing a severe impact on the environment and aquatic life. Photocatalytic degradation has been found as an inevitable approach to treat them. Herein, we decorated the copper oxide nanoparticles on graphene nanosheets during the reflux process. The resultant copper oxide/graphene nanocomposites were analyzed for structural and functional attributes. It was observed that on increasing the copper oxide contents, the z-average size of the resultant nanocomposites decreased. The X-ray diffraction analysis demonstrated the crystalline nature of the nanocomposite. The surface morphology of the copper oxide nanoparticles appeared to be spherical and that of the copper oxide/graphene composite somehow wrinkled. The infrared analysis indicated successful intercalation of precursors in the nanocomposite. The bandgap of copper oxide/graphene nanocomposites varied in the range of 1.03-1.30 eV, which indicated their effective photocatalytic activity. The results demonstrated that after 120 min of exposure, the methylene blue removal efficiency reached 94.0%, 92.2%, and 89.4%(mass fraction) on the copper oxide/graphene nanocomposite at copper oxide nanoparticles to graphene nanosheets ratios of 1:1, 1.5:1, and 2:1 (mass ratio), respectively. The photodegradation performance of the prepared nano-catalyst was found satisfactory even after five cycles.