Core-shell Sm2O3@ZnO nano-heterostructure for the visible light driven photocatalytic performance

ZnO-coated Sm2O3 (Sm2O3@ZnO) nano-heterostructure was prepared for the visible light driven photodegradation of RhB. Core-shell Sm2O3@ZnO composites exhibited the enhanced photocatalytic activity compared with pure Sm2O3 and ZnO nanoparticles alone for RhB removal. Sm2O3@ZnO with the ZnO thickness of around 10 nm presented the best photocatalytic capacity and slightly deactivated after five cycle times. It's attributed to the extended light-harvesting capability of the core-shell heterostructure toward visible light region and the tunneled valence band holes of Sm2O3 at the interface between Sm2O3 core and ZnO shell. The attenuated photocatalytic activity of Sm2O3@ZnO in subsequent reuse process was ascribed to the change of chemical surface composition of Sm2O3 under visible light irradiation. ESR results indicated that O-center dot(2)- radical was main responsible for the photocatalytic performance of Sm2O3@ZnO.