Fabrication of nanocomposite photocatalysts from zinc oxide nanostructures and reduced graphene oxide

Abstract

Reduced graphene oxide/zinc oxide (RGO/ZnO) nanocomposites were fabricated directly using a facile sintering method and evaluated as photocatalysts. Zinc nitrate and acetate powders were sintered in a furnace in the presence and absence of RGO (“graphene”) sheets at 450 °C for 1 h in air. The sintered samples were analyzed using various techniques and their photocatalytic activities toward methylene blue (MB) degradation were evaluated. Field-emission scanning electron microscopy images revealed the formation of pyramid- and nanorod-like structures for the cases of sintering without graphene. Sintering with RGO powders provided a uniform distribution of ZnO nanoparticles over graphene sheets. Transmission electron microscopy confirmed the good dispersion of the nanoparticles on the graphene sheets. The nanocomposites prepared by sintering RGO with zinc acetate had superior photocatalytic activity (40 min, k = 0.0521 min−1) for MB degradation under ultraviolet (UV) irradiation. Improved photocatalytic activity was the result of a large specific surface area (12.83 m2 g−1) and effective photoelectron separation and transportation by the graphene. Therefore, RGO/ZnO nanocomposites were found to be highly promising materials for UV photocatalysis.