Synthesis of hierarchical RGO@Cu2O@Cu nanocomposites: optimization of photocatalytic degradation of Direct Orange 39 using a response surface methodology

Abstract

The RGO@Cu2O@Cu nanocomposites were prepared by hydrothermal method using ethylene glycol, copper acetate and graphene oxide. The molar ratio of Cu2O to Cu in the nanocomposites was changed by adjusting the hydrothermal reaction time. The synthesized products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and UV–Vis spectroscopy. The field emission scanning electron microscopy (FE-SEM) image shows the reduced graphene oxide (RGO) sheets decorated by uniform hierarchical Cu2O@Cu spheres. The photocatalytic activity of synthesized nanocomposites on degradation of Direct Orange 39 (DO39) as a pollutant was determined by visible light irradiation. For this purpose, a model was developed by the central composite design to describe the degradation efficiency of DO39 as a function of the operational parameters. The interaction effects and optimal parameters were obtained by using statgraphics software. The percentage of degradation efficiency (%DE) of DO39 approached 90% under optimal conditions. Predicted values were found to be in good agreement with experimental values (R2 = 99.20 and Adj-R2 = 98.65) which confirm suitability of the model.