Self-assembly of CeO2 nanostructures/reduced graphene oxide composite aerogels for efficient photocatalytic degradation of organic pollutants in water

Reduced graphene oxide aerogels (RGAs) are excellent candidates for water remediation due to their lightweight, high surface area and high absorbance rate. Here, we report a simple green synthetic approach for the self-assembly of CeO2-RGA aerogels using vitamin-C as the reducing agent. The photocatalytic degradation performance of the as-synthesized CeO2-RGA aerogels was studied as a function of simulated sunlight irradiation, using the organic dye Rhodamine-B (RhB) as a test molecule. The CeO2/RGA composites displayed highly enhanced photocatalytic activity in comparison to bare CeO2 nanostructures. This enhancement is ascribed to efficient charge transfer from the CeO2 nanostructures to the reduced graphene oxide (RGO) sheets due to the high degree of interconnectivity between the RGO and CeO2 nanostructures. In addition, photoluminescence studies strongly support this charge separation mechanism. The microstructures and optical properties of the as-synthesized nanostructures were characterized using HRTEM, XRD, FTIR, XPS and DRS. These results demonstrated that the CeO2 nanostructures are grown on interconnected three-dimensional RGO nanosheets. We believe that the findings of this study provide a versatile pathway to induce self-assembly of reduced graphene sheets with other semiconductor nanostructures in the form of lightweight aerogels for a variety of environmental applications.