Synthesis of Yolk Shell Structured Fe3O4@void@CdS Nanoparticles: A General and Effective Structure Design for Photo-Fenton Reaction

Yolk-shell (Y-S) structured Fe3O4@void@CdS nanoparticles (NPs) are synthesized through a one-pot coating-etching process with Fe3O4@ SiO2 as the core, where the coating of an outer CdS shell from a chemical bath deposition (CBD) process is simultaneously accompanied by the gradual etching of an inner SiO2 shell. The as-prepared Fe3O4@void@CdS NPs (ca. 200 nm) possess good monodispersity and a uniform cdS shell of ca E15 This composite exhibits excellent photo-Fenton (ph-F) activity toward the degradation of methylene blue (MB) in a wide pH working range of 4.5-11 under the visible light irradiation. A series of control experiments demonstrate the unique Y S structure contributes to the enhanced activity, where the separation of hole electron pair from cdS and the reduction of Fe2+ from Fe3+ are mutually promoted. The similar efficiency can also be achieved when the shell component changes to TiO2, or CeO2, demonstrating a general strategy for the design of robust ph-F agent.