A novel synthesis of Ag@ZnO yolk-shell and ZnO hollow sphere nanostructures and comparison of their photocatalytic performances

ZnO hallow spheres and Ag@ZnO yolk-shell nanostructures were synthesized using a hydrothermal method and their dye absorption and photocatalytic performances were investigated. For ZnO hollow spheres preparation, carbon sphere templates were used and ZnO hollow spheres with average size of 200 nm were obtained. Also, Ag@C core-shell spheres with diameters of 350 nm were prepared by a hydrothermal method and were used as template to prepare Ag@ZnO yolk-shell spheres. The samples were characterized using XRD, SEM, TEM, EDX and FT-IR measurements. The results confirmed the formation of yolk-shell nanostructure. The average diameters of ZnO shells and Ag cores, 300 and 55 nm were measured respectively. Then Congo red dye absorption of ZnO hollow spheres and Ag@ZnO yolk-shells were examined. The results showed that the ZnO hollow spheres were a better dye absorbent, but Ag@ZnO yolk-shells had better photocatalytic performance probably due to presence of Ag nanoparticles as a plasmonic material.