Rapid sonochemical synthesis of copper doped ZnO grafted on graphene as a multi-component hierarchically structured visible-light-driven photocatalyst

Three-dimensional (3D) hierarchical structures (HSs) have demonstrated excellent properties for various applications that are attributable to their distinctive micro-sized architecture with nanoscale substructures. Recently, the ultrarapid sonochemical approach was found to be an effective strategy for synthesizing single component HSs with uniform morphologies in comparison to the direct precipitation technique. We here report the fabrication of copper doped zinc oxide grafted on graphene layers (ZnO-Cu_x-GO_y) for exploring the capability of this ultrarapid approach for synthesizing multi-component HSs. Interestingly, the morphology of ZnO-Cu_x-GO_y HSs studied through electron microscopy revealed the growth of ZnO HSs decorated with Cu nanoparticles and interconnected by graphene layers. ZnO-Cu_x-GO_y HSs demonstrated three-fold higher efficiency in the photodegradation of ibuprofen (IBU) under visible light irradiation in comparison to pristine ZnO HSs, which is attributable to the combined influence of the doped Cu²⁺ ions and graphene, enabling improved visible light absorption and inhibiting the recombination of photogenerated charges. Thus, the novel ultrarapid sonochemical synthesis strategy demonstrated here is anticipated to open up a new horizon for the time-saving and scalable design of multi-component HSs of various materials for a myriad of applications.