Core-shell structured alpha-Fe2O3@CeO2 heterojunction for the enhanced visible-light photocatalytic activity

CeO2-coated alpha-Fe2O3 nanoparticles (alpha-Fe2O3@CeO2) with the enhanced photocatalytic activity were synthesized by a hydrothermal route and performed for the visible light driven photo-degradation of methylene blue (MB). The photocatalytic activity of alpha-Fe2O3@CeO2 is greatly affected by the thickness of CeO2 shell under the same conditions. The core-shell structured alpha-Fe2O3@CeO2 sample exhibited a narrower band gap energy in comparison to the pure alpha-Fe2O3 and CeO2 bulks, leading to the excellent photocatalytic activity and stability for the degradation of MB under visible light irradiation after five cycle times. The core-shell structured alpha-Fe2O3@CeO2 sample presented higher degradation activity than that of the supported 8-Fe/CeO2 bulks with optimized alpha-Fe2O3 loading of 8%. It can be ascribed to the Ce4+/Ce3+ redox couple and the heterojunction interfaces of core-shell structured alpha-Fe2O3@CeO2 sample, which can promote the electrons transfer and restrain the photoexcited electron-hole recombination, leading to the excellent degradation activity under visible light irradiation.