Fluorine-doped TiO2 sol（F-TiO2） was prepared by the modified precipitation-sol-hydrothermal crystallization method with TiCl4 as precursor.The influences of F doping, temperature and time of hydrothermal crystalliza...Fluorine-doped TiO2 sol（F-TiO2） was prepared by the modified precipitation-sol-hydrothermal crystallization method with TiCl4 as precursor.The influences of F doping, temperature and time of hydrothermal crystallization, medium pH value on the morphology and crystallization were studied.The particle size and structure of the prepared F-TiO2 sol as well as the interaction of F with TiO2 were characterized with XRD, UV-Vis-DRS, TEM, TG-DTA, FTIR and XPS.The results showed that F-TiO2 particles in sol were spherical, and partly crystallized to anatase.They were dispersed in the aqueous medium uniformly and showed narrow particle size distribution.The average particle size was 6.5 nm as calculated from XRD and TEM results.It was also shown that fluorine atoms were adsorbed by TiO2 sol particles in two forms.One was physically adsorbed on the surface of TiO2, and the other was embedded into TiO2 crystal lattice.It was found that the addition of fluorine could improve the crystallization of particle significantly, decrease the temperature and shorten the time of hydrothermal crystallization.The adsorption capacity, surface acidity and the photocatalytic activity for decomposition of Rhodamine B were enhanced remarkably with the doping of fluorine.The mechanism of improvement of the photocatalytic activity and structure of TiO2 by fluorine was discussed.展开更多
Ultrafine cube-shape Ce2Sn2O7 nanoparticles crystallized in pure pyrochlore phase with a size of about 10 nm have been successfully synthesized by a facile hydrothermal method.Conditional experiments have been conduct...Ultrafine cube-shape Ce2Sn2O7 nanoparticles crystallized in pure pyrochlore phase with a size of about 10 nm have been successfully synthesized by a facile hydrothermal method.Conditional experiments have been conducted to optimize the processing parameters including temperature,pH,reaction duration,precipitator types to obtain phase-pure Ce2Sn2O7.The crystal structure,morphology and sizes and specific surface area have been characterized by X-ray diffractometer(XRD),Raman spectrum,transmission electron microscope(TEM),high resolution transmission electron microscope(HRTEM),and Brunauer-Emmett-Teller(BET).The as-synthesized Ce2Sn2O7 ultrafine nanocubes have been evaluated as electrode materials for pseudo-capacitors and lithium ion batteries.When testing as supercapacitors,a high specific capacitance of 222 F/g at 0.1 A/g and a good cycling stability with a capacitance retention of higher than 86%after 5000 cycle have been achieved.When targeted for anode material for lithium ion batteries,the nanocubes deliver a high specific reversible capacity of more than 900 mA·h/g at 0.05C rate.The rate capability and cycling performance is also very promising as compared with the traditional graphite anode.展开更多
文摘Fluorine-doped TiO2 sol（F-TiO2） was prepared by the modified precipitation-sol-hydrothermal crystallization method with TiCl4 as precursor.The influences of F doping, temperature and time of hydrothermal crystallization, medium pH value on the morphology and crystallization were studied.The particle size and structure of the prepared F-TiO2 sol as well as the interaction of F with TiO2 were characterized with XRD, UV-Vis-DRS, TEM, TG-DTA, FTIR and XPS.The results showed that F-TiO2 particles in sol were spherical, and partly crystallized to anatase.They were dispersed in the aqueous medium uniformly and showed narrow particle size distribution.The average particle size was 6.5 nm as calculated from XRD and TEM results.It was also shown that fluorine atoms were adsorbed by TiO2 sol particles in two forms.One was physically adsorbed on the surface of TiO2, and the other was embedded into TiO2 crystal lattice.It was found that the addition of fluorine could improve the crystallization of particle significantly, decrease the temperature and shorten the time of hydrothermal crystallization.The adsorption capacity, surface acidity and the photocatalytic activity for decomposition of Rhodamine B were enhanced remarkably with the doping of fluorine.The mechanism of improvement of the photocatalytic activity and structure of TiO2 by fluorine was discussed.
基金Project(JCYJ20170817110251498)supported by the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen,ChinaProject(2016TQ03C919)supported by the Guangdong Special Support for the Science and Technology Leading Young Scientist,ChinaProjects(21603094,21703096)supported by the National Natural Science Foundation of China
文摘Ultrafine cube-shape Ce2Sn2O7 nanoparticles crystallized in pure pyrochlore phase with a size of about 10 nm have been successfully synthesized by a facile hydrothermal method.Conditional experiments have been conducted to optimize the processing parameters including temperature,pH,reaction duration,precipitator types to obtain phase-pure Ce2Sn2O7.The crystal structure,morphology and sizes and specific surface area have been characterized by X-ray diffractometer(XRD),Raman spectrum,transmission electron microscope(TEM),high resolution transmission electron microscope(HRTEM),and Brunauer-Emmett-Teller(BET).The as-synthesized Ce2Sn2O7 ultrafine nanocubes have been evaluated as electrode materials for pseudo-capacitors and lithium ion batteries.When testing as supercapacitors,a high specific capacitance of 222 F/g at 0.1 A/g and a good cycling stability with a capacitance retention of higher than 86%after 5000 cycle have been achieved.When targeted for anode material for lithium ion batteries,the nanocubes deliver a high specific reversible capacity of more than 900 mA·h/g at 0.05C rate.The rate capability and cycling performance is also very promising as compared with the traditional graphite anode.
