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
Hierarchical Sb_2S_3 hollow microspheres assembled by nanowires have been successfully synthesized by a simple and practical hydrothermal reaction. The possible formation process of this architecture was investigated ...Hierarchical Sb_2S_3 hollow microspheres assembled by nanowires have been successfully synthesized by a simple and practical hydrothermal reaction. The possible formation process of this architecture was investigated by X-ray diffraction, focused-ion beam-scanning electron microscopy dual-beam system, and transmission electron microscopy. When used as the anode material for lithium-ion batteries, Sb_2S_3 hollow microspheres manifest excellent rate property and enhanced lithium-storage capability and can deliver a discharge capacity of 674 m Ah g^(-1) at a current density of 200 m A g^(-1) after 50 cycles. Even at a high currentdensity of 5000 m A g^(-1), a discharge capacity of541 m Ah g^(-1) is achieved. Sb_2S_3 hollow microspheres also display a prominent sodium-storage capacity and maintain a reversible discharge capacity of 384 m Ah g^(-1) at a current density of 200 m A g^(-1) after 50 cycles. The remarkable lithium/sodium-storage property may be attributed to the synergetic effect of its nanometer size and three-dimensional hierarchical architecture, and the outstanding stability property is attributed to the sufficient interior void space,which can buffer the volume expansion.展开更多
Al2 O3 hollow microspheres without noticeable aggregation have been prepared via a facile templating route with urea-mediated precipitation. The precipitation process is different from the surfaceadsorption method whi...Al2 O3 hollow microspheres without noticeable aggregation have been prepared via a facile templating route with urea-mediated precipitation. The precipitation process is different from the surfaceadsorption method which is confined to the adsorption capacity of the template surface. TEM and SEM images indicate that most of these Al2 O3 hollow microspheres with shell thickness of tens of nanometers and diameters in a narrow range of 100-200 nm consist of a shell of closely packed nanoparticles. The optimal amount of H2 O and EtOH are 40 and 120 m L, respectively. The specific surface area, average pore size and pore volume of the Al2 O3 hollow microspheres（calcinated at 600 ℃） are 328.52 m2/g, 17.496 nm and 1.985 cm3/g, respectively. As the calcination temperature increases from 600 to 1 100 ℃, the phase composition changes from γ-Al2 O3 to θ-Al2 O3 and a-Al2 O3, and the surface morphology appears to change from a relatively rough surface formed by nanoparticles to a smooth surface formed by lamellar, which lead to the closure of pore channels and the reduction of specific surface.展开更多
Hollow Glass Microspheres are high-strength, low-density additives made from water resistant and chemically-stable soda-lime-borosilicate glass. These hollow glass microspheres offer a variety of advantages over conve...Hollow Glass Microspheres are high-strength, low-density additives made from water resistant and chemically-stable soda-lime-borosilicate glass. These hollow glass microspheres offer a variety of advantages over conventional irregularly-shaped mineral fillers or glass fiber. Their spherical shape helps reduce resin content in a variety of applications. They also create a ball bearing effect that can result in higher filler loading and improved flow. In this research, amine terminated hollow glass microspheres were prepared by adopting three different routes. The results were investigated using FT-IR and SEM to establish the formation of amine groups and observe the morphological structure of the modified HGMs. The results obtained were used to select a suitable less toxic and environmental friendly modification method based on the chemicals used.展开更多
Vesicular lithium vanadium phosphate/carbon hollow mesoporous microspheres were fabricated using a facile polyvinylpyrrolidone-assisted aerosol-spray-assisted method and subsequent heat-treatment. While changing the c...Vesicular lithium vanadium phosphate/carbon hollow mesoporous microspheres were fabricated using a facile polyvinylpyrrolidone-assisted aerosol-spray-assisted method and subsequent heat-treatment. While changing the content of polyvinylpyrrolidone, we found that carbon content was adjustable on the surface of lithium vanadium phosphate. By optimizing the carbon content among the composites, the electrochemical performance can be enhanced significantly. The results of electrochemical performance tests suggested that the samples exhibited good cycle performance and high discharge capability in the voltages between 3.0-4.8 V. The observed excellent electrochemical performances could be attributed to the proper content of carbon coating and the vesicular hollow mesoporous microsphere structure, increasing the transmission rate of lithium ions and reducing the structural change during charging and discharging effectively.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
For decades,distiller waste and CO_(2) were not the first choice for production of high valued products.Here,CaCO_(3) hollow microspheres,a high-value product was synthesized from such a reaction system.The synthetic ...For decades,distiller waste and CO_(2) were not the first choice for production of high valued products.Here,CaCO_(3) hollow microspheres,a high-value product was synthesized from such a reaction system.The synthetic methods,the formation mechanism and operational cost were discussed.When 2.5 L·min^(–1)·L^(–1) CO_(2) was flowed into distiller waste(pH=11.4),spheres with 4–13μm diameters and about 2μm shell thickness were obtained.It is found that there is a transformation of CaCO_(3) particles from solid-cubic nuclei to hollow spheres.Firstly,the Ca(OH)_(2) in the distiller waste stimulated the nucleation of calcite with a non-template effect and further maintained the calcite form and prevented the formation of vaterite.Therefore,in absence of auxiliaries,the formation of hollow structures mainly depended on the growth and aging of CaCO_(3).Studies on the crystal morphology and its changes during the growth process point to the inside–out Ostwald effect in the formation of hollow spheres.Change in chemical properties of the bulk solution caused changes in interfacial tension and interfacial energy,which promoted the morphological transformation of CaCO_(3) particles from cubic calcite to spherical clusters.Finally,the flow process for absorption of CO_(2) by distiller waste was designed and found profitable.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.
基金supported financially by the National Natural Foundation of China(Grant No.51672234)the Research Foundation for Hunan Youth Outstanding People from Hunan Provincial Science and Technology Department(2015RS4030)+1 种基金Hunan 2011 Collaborative Innovation Center of Chemical Engineering&Technology with Environmental Benignity and Effective Resource UtilizationProgram for Innovative Research Cultivation Team in University of Ministry of Education of China(1337304)
文摘Hierarchical Sb_2S_3 hollow microspheres assembled by nanowires have been successfully synthesized by a simple and practical hydrothermal reaction. The possible formation process of this architecture was investigated by X-ray diffraction, focused-ion beam-scanning electron microscopy dual-beam system, and transmission electron microscopy. When used as the anode material for lithium-ion batteries, Sb_2S_3 hollow microspheres manifest excellent rate property and enhanced lithium-storage capability and can deliver a discharge capacity of 674 m Ah g^(-1) at a current density of 200 m A g^(-1) after 50 cycles. Even at a high currentdensity of 5000 m A g^(-1), a discharge capacity of541 m Ah g^(-1) is achieved. Sb_2S_3 hollow microspheres also display a prominent sodium-storage capacity and maintain a reversible discharge capacity of 384 m Ah g^(-1) at a current density of 200 m A g^(-1) after 50 cycles. The remarkable lithium/sodium-storage property may be attributed to the synergetic effect of its nanometer size and three-dimensional hierarchical architecture, and the outstanding stability property is attributed to the sufficient interior void space,which can buffer the volume expansion.
文摘Al2 O3 hollow microspheres without noticeable aggregation have been prepared via a facile templating route with urea-mediated precipitation. The precipitation process is different from the surfaceadsorption method which is confined to the adsorption capacity of the template surface. TEM and SEM images indicate that most of these Al2 O3 hollow microspheres with shell thickness of tens of nanometers and diameters in a narrow range of 100-200 nm consist of a shell of closely packed nanoparticles. The optimal amount of H2 O and EtOH are 40 and 120 m L, respectively. The specific surface area, average pore size and pore volume of the Al2 O3 hollow microspheres（calcinated at 600 ℃） are 328.52 m2/g, 17.496 nm and 1.985 cm3/g, respectively. As the calcination temperature increases from 600 to 1 100 ℃, the phase composition changes from γ-Al2 O3 to θ-Al2 O3 and a-Al2 O3, and the surface morphology appears to change from a relatively rough surface formed by nanoparticles to a smooth surface formed by lamellar, which lead to the closure of pore channels and the reduction of specific surface.
文摘Hollow Glass Microspheres are high-strength, low-density additives made from water resistant and chemically-stable soda-lime-borosilicate glass. These hollow glass microspheres offer a variety of advantages over conventional irregularly-shaped mineral fillers or glass fiber. Their spherical shape helps reduce resin content in a variety of applications. They also create a ball bearing effect that can result in higher filler loading and improved flow. In this research, amine terminated hollow glass microspheres were prepared by adopting three different routes. The results were investigated using FT-IR and SEM to establish the formation of amine groups and observe the morphological structure of the modified HGMs. The results obtained were used to select a suitable less toxic and environmental friendly modification method based on the chemicals used.
基金supported by the National Natural Science Foundation of China (Nos.21871005 and 21471006)the Recruitment Program for Leading Talent Team of Anhui Province, the Program for Innovative Research Team of Anhui Education Committee, the Research Foundation for Science and Technology Leaders and Candidates of Anhui Province, the programs for Science and Technology Development of Anhui Province (No.1501021019)Anhui Normal University talent training program (No.2014rcpyl2).
文摘Vesicular lithium vanadium phosphate/carbon hollow mesoporous microspheres were fabricated using a facile polyvinylpyrrolidone-assisted aerosol-spray-assisted method and subsequent heat-treatment. While changing the content of polyvinylpyrrolidone, we found that carbon content was adjustable on the surface of lithium vanadium phosphate. By optimizing the carbon content among the composites, the electrochemical performance can be enhanced significantly. The results of electrochemical performance tests suggested that the samples exhibited good cycle performance and high discharge capability in the voltages between 3.0-4.8 V. The observed excellent electrochemical performances could be attributed to the proper content of carbon coating and the vesicular hollow mesoporous microsphere structure, increasing the transmission rate of lithium ions and reducing the structural change during charging and discharging effectively.
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%.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.U20A20149,21878180 and 21908137)the Graduate Education Project of Shanxi Province(NO.2021Y139).
文摘For decades,distiller waste and CO_(2) were not the first choice for production of high valued products.Here,CaCO_(3) hollow microspheres,a high-value product was synthesized from such a reaction system.The synthetic methods,the formation mechanism and operational cost were discussed.When 2.5 L·min^(–1)·L^(–1) CO_(2) was flowed into distiller waste(pH=11.4),spheres with 4–13μm diameters and about 2μm shell thickness were obtained.It is found that there is a transformation of CaCO_(3) particles from solid-cubic nuclei to hollow spheres.Firstly,the Ca(OH)_(2) in the distiller waste stimulated the nucleation of calcite with a non-template effect and further maintained the calcite form and prevented the formation of vaterite.Therefore,in absence of auxiliaries,the formation of hollow structures mainly depended on the growth and aging of CaCO_(3).Studies on the crystal morphology and its changes during the growth process point to the inside–out Ostwald effect in the formation of hollow spheres.Change in chemical properties of the bulk solution caused changes in interfacial tension and interfacial energy,which promoted the morphological transformation of CaCO_(3) particles from cubic calcite to spherical clusters.Finally,the flow process for absorption of CO_(2) by distiller waste was designed and found profitable.
