In situ Oxidation and Self-Assembly Synthesis of Dumbbell-like α-Fe2O3/Ag/AgX (X = CI, Br, I) Heterostructures with Enhanced Photocatalytic Properties

In this work, the novel dumbbell-like alpha-Fe2O3/Ag/AgX (X = Cl, Br, I) heterostructures were successfully synthesized via an in situ oxidation reaction and self-assembly process by using the alpha-Fe2O3/Ag core shell nanoparticles (NPs). The as-obtained dumbbell-like alpha-Fe2O3/Ag/AgX heterostructure contains an individual spindle like alpha-Fe2O3 nanoparticle and a single near-spherical Ag/AgX nanoparticle. The morphology, microstructure, component and optical property of as-synthesized alpha-Fe2O3/Ag/AgX heterostructures were characterized by various analytical techniques. The great changing of morphology and component in such synthesis route make great effect on the final photocatalytic performance. The dumbbell-like alpha-Fe2O3/Ag/AgX heterostructures exhibit excellent photocatalytic activity for the degradation of RhB dye under simulated sunlight irradiation. In particular, the alpha-Fe2O3/Ag/AgCl can completely degrade RhB molecules within only 20 min under simulated sunlight irradiation, which is superior to the pure alpha-Fe2O3, a-Fe2O3/Ag NPs, and commercial P25. The enhanced activity is attributed to the efficient interfacial charge rectification and faster carrier migration in the alpha-Fe2O3/Ag/AgX heterostructures. Furthermore, the degradation rate of as-synthesized dumbbell-like alpha-Fe2O3/Ag/AgX (X = Cl, Br, I) heterostructures follows this order: alpha-Fe2O3/Ag/AgCl > alpha-Fe2O3/Ag/AgBr > alpha-Fe2O3/Ag/AgI. The results can be owing to that the oxidation capability of Cl-0 is stronger than Br and I. This unique synthetic work can provide physical insight into prepare novel nanomaterials with special structures and properties, which can apply in photocatalysis, photosplitting of water and solar cell, etc.