Enhanced photocatalytic activities of ZnO dumbbell/reduced graphene oxide nanocomposites for degradation of organic pollutants via efficient charge separation pathway

Abstract

In the present work, a well-defined dumbbell shaped ZnO was synthesized by hydrothermal method and ZnO dumbbell/reduced graphene oxide (ZnO/rGO) nanocomposites were prepared by a simple solution mixing method with the different rGO loading amount. The formation of nanocomposites, crystal structure, shape, size and optical properties of the ZnO/rGO nanocomposites were investigated using various analytical techniques. The photocatalytic degradation efficiency of synthesized materials was evaluated by the degradation of aqueous Methyl Orange (MO) and Methylene Blue (MB) under UV–Visible light irradiation. The results revealed that 3 wt% rGO loaded ZnO dumbbell (ZnO-3% rGO) exhibited the higher photocatalytic degradation efficiency than pure ZnO dumbbell and rGO. The enhancement in the photocatalytic dye degradation efficiency of ZnO-3% rGO is attributed to the efficient dye adsorption nature, a red shift in light absorption and inhibition of photo-excited electron-hole pair recombination rate. The photocatalytic dye degradation efficiency also evaluated for various catalyst dosage, dye concentration and pH of the solution. Moreover, it was demonstrated the stability of catalyst over a repeated cycle of dye treatment.