Preparation of SiO₂@Au@TiO₂ core-shell nanostructures and their photocatalytic activities under visible light irradiation

详细信息    查看全文

• 作者：Miaomiao Ye ; Huihui Zhou ; Tuqiao Zhang ; Yiping Zhang ; Yu Shao ; ^{shaoyu1979@zju.edu.cn}
• 关键词：Core&ndash ; shell nanostructures ; Plasmonic effects ; Photocatalysis ; Titania ; Naproxen
• 刊名：Chemical Engineering Journal
• 出版年：2013
• 出版时间：15 June, 2013
• 年：2013
• 卷：226
• 期：Complete
• 页码：209-216
• 全文大小：1994 K

文摘

SiO₂@Au@TiO₂ core-shell nanostructures with tunable decoration amount of Au nanoparticles have been successfully synthesized by combining three individual synthesis steps with calcination. The as-prepared samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), N₂ adsorption-desorption, X-ray photoelectron emission spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy. The photocatalytic activities of the samples were evaluated by photocatalytic degradation of naproxen in aqueous solution under visible light irradiation. Results show that the as-obtained core-shell nanostructure is composed of a SiO₂ core with an average diameter of ¡«337 nm, tunable content of Au nanoparticles adsorbed on the surface of SiO₂ core, and an outer layer of TiO₂ with an average thickness of ¡«7.0 nm. Photocatalysis experiments indicate that the SiO₂@Au@TiO₂ core-shell nanostructures with Au decoration amount of 0.1 wt % (denotes as SiAuTi-2) exhibit the highest photocatalytic activity since it has the suitable decoration amount of Au nanoparticles for harvesting the visible-light energy and for prohibiting the recombination of free excitons. For fast separation of the catalysts, superparamagnetic cores of Fe₃O₄ were embedded in the SiO₂@Au@TiO₂ core-shell nanostructures and hence they can be separated from aqueous solution by an external magnetic field within 10 min.