title: Synthesis of double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres and their catalytic applications.
abstract: Double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres were successfully synthesized through loading Au nanoparticles on the Fe3O4/TiO2 support by a in situ reduction of HAuCl4 with NaBH4 aqueous solution. These microspheres possess tunable cavity size, adjustable shell layers, high structural stability and large specific surface area. The Au nanoparticles of approximately 5 nm in diameter were loaded both on the TiO2 nanofibers and inside the cavities of sea urchin-like yolk-shell Fe3O4/TiO2 microspheres. The sea urchin-like structure composed of TiO2 nanofibers ensure the good distribution of the Au nanoparticles, while the novel double-shelled yolk-shell structure guarantees the high stability of the Au nanoparticles. Furthermore, the Fe3O4 magnetic core facilitates the convenient recovery of the catalyst by applying an external magnetic field. The Fe3O4/TiO2/Au microspheres display excellent activities and recycling properties in the catalytic reduction of 4-nitrophenol (4-NP): the rate constant is 1.84 min(-1) and turnover frequency is 5457 h(-1).
authors: School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China.
authors: Jie
authors: J
authors: Li
authors: Li
authors: L
authors: Tan
authors: Ge
authors: G
authors: Wang
authors: Mu
authors: M
authors: Yang
mesh_terms: D002384:Catalysis; D006046:Gold / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008863:Microspheres; D014025:Titanium / Q000737:chemistry
chemical_list: D058185:Magnetite Nanoparticles; C009495:titanium dioxide; D006046:Gold; D014025:Titanium