Template-Assisted Fabrication of Magnetically Responsive Hollow Titania Capsules

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• 作者：Mukesh Agrawal ; Smrati Gupta ; Andrij Pich ; Nikolaos E. Zafeiropoulos ; Jorge Rubio-Retama ; Dieter Jehnichen ; Manfred Stamm
• 刊名：Langmuir
• 出版年：2010
• 出版时间：November 16, 2010
• 年：2010
• 卷：26
• 期：22
• 页码：17649-17655
• 全文大小：944K
• 年卷期：v.26,no.22(November 16, 2010)
• ISSN：1520-5827

文摘

This study reports on the fabrication of magnetically responsive hollow titania capsules by confining the superparamagnetic Fe₃O₄ nanoparticles within a hollow and porous titania (TiO₂) shell. The employed protocol involves precipitation of titania shell on the magnetite (Fe₃O₄) encapsulated polystyrene beads followed by the calcination of resulting composite particles at elevated temperature. Scanning electron microscopy and transmission electron microscopy reveal the presence of a thick, complete but irregular titania shell on the magnetic polystyrene beads after the templating process. Electron energy loss mapping image analysis has been employed to investigate the spatial distribution of titania and magnetite phases of magnetic hollow titania capsules (MHTCs). Magnetic characterization indicates that both titania-coated magnetic polystyrene beads (TMPBs) and MHTCs are superparamagnetic in nature with the saturated magnetizations of 5.6 and 8.1 emu/g, respectively. X-ray diffraction (XRD) analysis reveals that titania shell of these capsules is composed of photoactive anatase phase. Nitrogen adsorption−desorption analysis has been employed to estimate the specific surface area and the average pore diameter of the fabricated hollow structures. Photocatalytic activity of the fabricated MHTCs for the photodegradation of rhodamine 6G dye has been demonstrated and compared with that of bulk titania nanoparticles.