Graphene Quantum Dots Enhanced Photocatalytic Activity of Sb2WO6 Under Ultraviolet- and Visible-Light Irradiation

A novel composite of graphene quantum dots functionalized Sb2WO6 (GQDs/Sb2WO6) was prepared by an electrostatic self-assembly method and used as a photocatalyst for the degradation of an organic pollutant. The resulting GQDs/Sb2WO6 was characterized by electron microscopy and optical measurements. The photocatalytic activity of GQDs/Sb2WO6 was investigated by degrading methyl orange (MO) under UV-light and visible-light irradiation. Compared with pure Sb2WO6, enhancement of the photocatalytic performance of GQDs/Sb2WO6 was achieved, and the degradation efficiency for MO was almost 100% within 3 h under UV-light irradiation and 71.4% within 3 h under visible-light irradiation. The photocatalytic degradation mechanism of GQDs/Sb2WO6 was illustrated by free radical and hole scavenging experiments, and the main active species were confirmed to be holes (h(+)) and superoxide anion radicals (O-2 center dot(-)). Moreover, the GQDs/Sb2WO6 composites exhibited high recyclability and stability and had potential application for decomposing other organic contaminants in water.