Assembly and enhanced elimination performance of 3D graphene aerogel-zinc oxide hybrids for methylene blue dye in water

The hybrid consisting of ZnO nanocrystals and graphene aerogel (GA) are facilely assembled with a one-pot hydrothermal method combined with freeze-drying process. Their adsorption capacity and photocatalytic degradation performance in the removal of methylene blue (MB) under visible and UV light irradiation are evaluated in details. The results show that the hybrids exhibit much better adsorptivity and higher photocatalytic activity than pristine ZnO and most of the ZnO-based materials reported previously. Meanwhile, the hybrids also possess excellent photochemical stability. Among them, GA-ZnO(5) displays the highest adsorptive efficiency (94.2%) and the best total removal efficiency for MB dye (95.9%) under visible light irradiation. And GA-ZnO(3) exhibits the best total removal efficiency (97.6%) irradiated by UV light under the harsh conditions. A possible photocatalytic mechanism is also proposed. As a result, the 3D GA-ZnO hybrids are confirmed to be a promising functional material in field of wastewater remediation.