Fabrication of TiO 2 hollow microspheres（TiO 2-HMSs） has attracted considerable attention owing to their low density,high photoreactivity,and easy to separate and reuse. A fluoride-free method for the fabrication of...Fabrication of TiO 2 hollow microspheres（TiO 2-HMSs） has attracted considerable attention owing to their low density,high photoreactivity,and easy to separate and reuse. A fluoride-free method for the fabrication of TiO 2-HMSs is reported by refluxing a mixed solution of H3PW12O40（0.4 mmol）,KCl（2.5 mmol） and Ti（SO4）2（2–25 mmol） at 125 °C for 8 h,followed by decomposition of the K3PW12O40（KPW） template in basic solution. The prepared TiO 2-HMSs are characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,Fourier transform infrared spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The activities of the photocatalysts are evaluated by photocatalytic degradation of Brilliant Red X-3B,an anionic dye,under UV irradiation. It is observed that the TiO 2-HMSs exhibit diameters of approximately 0.5–1 μm,and the photocatalytic activity of TiO 2-HMSs initially increases and then decreases with an increasing amount of Ti（SO4）2. The TiO 2-HMSs prepared in the presence of 4 mmol Ti（SO4）2 exhibit the highest photocatalytic activity,which is 2.1 times higher than TiO 2 nanoparticles（prepared in the absence of the KPW template）. The enhanced photocatalytic activity of the prepared TiO 2-HMSs is ascribed to the improved crystallization,coupling effect between TiO 2and the residual KPW template,and the unique hollow structures of TiO 2-HMSs.展开更多
Gd^(3+)-doped monodisperse TiO_2 hollow microspheres with various molar ratios of Gd^(3+)/TBOT were synthesized via a novel process, which involved the preparation of SiO_2 templates, deposition of Gd^(3+)-doped TiO_2...Gd^(3+)-doped monodisperse TiO_2 hollow microspheres with various molar ratios of Gd^(3+)/TBOT were synthesized via a novel process, which involved the preparation of SiO_2 templates, deposition of Gd^(3+)-doped TiO_2 by sol-gel, SiO_2 coating, heat treatment to induce crystallization of TiO_2, and finally etching away the inner SiO_2 templates and outer SiO_2 layers. The synthesized samples were characterized by transmission electron microscopy(TEM), scanning electron microscopy(SEM), X-ray diffraction(XRD), diffuse reflection spectroscopy(DRS), specific surface area measurement(BET) and X-ray photoelectron spectroscopy(XPS), respectively. The photocatalytic activity of Gd^(3+)-doped samples was evaluated via photocatalytic degradation of Methyl orange under UV irradiation. The results show that the SiO_2 layers prevent aggregation of TiO_2 hollow microspheresand improve the thermal stability of the synthesized samples. Also, the photocatalytic activity of monodisperse TiO_2 hollow microspheres can be enhanced at the optimal molar ration of Gd^(3+)/TBOT of 0.7%.展开更多
基金supported by Program for New Century Excellent Talents in University(NCET-12-0668)the National Natural Science Foundation of China(21373275120977114)~~
文摘Fabrication of TiO 2 hollow microspheres（TiO 2-HMSs） has attracted considerable attention owing to their low density,high photoreactivity,and easy to separate and reuse. A fluoride-free method for the fabrication of TiO 2-HMSs is reported by refluxing a mixed solution of H3PW12O40（0.4 mmol）,KCl（2.5 mmol） and Ti（SO4）2（2–25 mmol） at 125 °C for 8 h,followed by decomposition of the K3PW12O40（KPW） template in basic solution. The prepared TiO 2-HMSs are characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,Fourier transform infrared spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The activities of the photocatalysts are evaluated by photocatalytic degradation of Brilliant Red X-3B,an anionic dye,under UV irradiation. It is observed that the TiO 2-HMSs exhibit diameters of approximately 0.5–1 μm,and the photocatalytic activity of TiO 2-HMSs initially increases and then decreases with an increasing amount of Ti（SO4）2. The TiO 2-HMSs prepared in the presence of 4 mmol Ti（SO4）2 exhibit the highest photocatalytic activity,which is 2.1 times higher than TiO 2 nanoparticles（prepared in the absence of the KPW template）. The enhanced photocatalytic activity of the prepared TiO 2-HMSs is ascribed to the improved crystallization,coupling effect between TiO 2and the residual KPW template,and the unique hollow structures of TiO 2-HMSs.
文摘Gd^(3+)-doped monodisperse TiO_2 hollow microspheres with various molar ratios of Gd^(3+)/TBOT were synthesized via a novel process, which involved the preparation of SiO_2 templates, deposition of Gd^(3+)-doped TiO_2 by sol-gel, SiO_2 coating, heat treatment to induce crystallization of TiO_2, and finally etching away the inner SiO_2 templates and outer SiO_2 layers. The synthesized samples were characterized by transmission electron microscopy(TEM), scanning electron microscopy(SEM), X-ray diffraction(XRD), diffuse reflection spectroscopy(DRS), specific surface area measurement(BET) and X-ray photoelectron spectroscopy(XPS), respectively. The photocatalytic activity of Gd^(3+)-doped samples was evaluated via photocatalytic degradation of Methyl orange under UV irradiation. The results show that the SiO_2 layers prevent aggregation of TiO_2 hollow microspheresand improve the thermal stability of the synthesized samples. Also, the photocatalytic activity of monodisperse TiO_2 hollow microspheres can be enhanced at the optimal molar ration of Gd^(3+)/TBOT of 0.7%.
