A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use o...A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 （CO3）4 （OH）2·4H2O were characterized by means of X-ray diffractometry （XRD）, fieldemission scanning electron microscopy（FE-SEM）. Brunauer-Emmett-Teller（BET） surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 （CO3）4（ OH）2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol.展开更多
Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part i...Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part icles were characterized by powder X ray diffraction(XRD),thermal analysis(TGA DSC), infrared spectroscopy(FT IR),transmission electron microscopy(SEM) and scanning electron microscopy(TEM). The size distribution in whisker like and nanocrystalline materials arein the range of 10～50μm and 10～20nm respectively. The whisker MOS is metastable phase in MgSO4 NaOH H2O system at 140℃,whereas nanometer MOS is stable phase.展开更多
Nanocrystalline MgSO\-4·5Mg（OH）\-2·3H\-2O were prepared by the hydrothermal reaction at 140 ℃ for 24 h. Nanoparticle samples were characterized by FTIR, TG, DSC, XRD and TEM. The size distribution of nano...Nanocrystalline MgSO\-4·5Mg（OH）\-2·3H\-2O were prepared by the hydrothermal reaction at 140 ℃ for 24 h. Nanoparticle samples were characterized by FTIR, TG, DSC, XRD and TEM. The size distribution of nanocrystalline is in the range of 10\20 nm, the mean size is 16 nm.展开更多
High-quality LDH-NO_3-CO_3 whiskers were synthesized via a liquid precipitation method using Mg(NO_3)_2·6H_2O and Al(NO_3)_3·9H_2O as raw materials and Na_2CO_3-NaHCO_3 buffer solutions as precipitant. The w...High-quality LDH-NO_3-CO_3 whiskers were synthesized via a liquid precipitation method using Mg(NO_3)_2·6H_2O and Al(NO_3)_3·9H_2O as raw materials and Na_2CO_3-NaHCO_3 buffer solutions as precipitant. The whiskers were characterized by X-ray diffraction, transmission electron microscope, and Brunauer-Emmett-Teller N_2 surface area measurement. The influence of buffer solution concentration on the characteristics of the sample was investigated. The results show that the buffer solution concentration has significant impact on whiskers with intercalated structure. Overall, LDH-NO_3-CO_3 whiskers with well-defined geometry, distinct intercalated structure, high quality, and good dispersion capability can be obtained under the following conditions: buffer solution volumetric ratio of 60%, reaction temperature of 55°C, and reaction time of 269 h.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.20671011,20331010,90406002and90406024)the 111 Project(No.B07012)the Key Laboratory of Structural Chemistry Foundation(No.060017).
文摘A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 （CO3）4 （OH）2·4H2O were characterized by means of X-ray diffractometry （XRD）, fieldemission scanning electron microscopy（FE-SEM）. Brunauer-Emmett-Teller（BET） surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 （CO3）4（ OH）2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol.
文摘Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part icles were characterized by powder X ray diffraction(XRD),thermal analysis(TGA DSC), infrared spectroscopy(FT IR),transmission electron microscopy(SEM) and scanning electron microscopy(TEM). The size distribution in whisker like and nanocrystalline materials arein the range of 10～50μm and 10～20nm respectively. The whisker MOS is metastable phase in MgSO4 NaOH H2O system at 140℃,whereas nanometer MOS is stable phase.
文摘Nanocrystalline MgSO\-4·5Mg（OH）\-2·3H\-2O were prepared by the hydrothermal reaction at 140 ℃ for 24 h. Nanoparticle samples were characterized by FTIR, TG, DSC, XRD and TEM. The size distribution of nanocrystalline is in the range of 10\20 nm, the mean size is 16 nm.
文摘High-quality LDH-NO_3-CO_3 whiskers were synthesized via a liquid precipitation method using Mg(NO_3)_2·6H_2O and Al(NO_3)_3·9H_2O as raw materials and Na_2CO_3-NaHCO_3 buffer solutions as precipitant. The whiskers were characterized by X-ray diffraction, transmission electron microscope, and Brunauer-Emmett-Teller N_2 surface area measurement. The influence of buffer solution concentration on the characteristics of the sample was investigated. The results show that the buffer solution concentration has significant impact on whiskers with intercalated structure. Overall, LDH-NO_3-CO_3 whiskers with well-defined geometry, distinct intercalated structure, high quality, and good dispersion capability can be obtained under the following conditions: buffer solution volumetric ratio of 60%, reaction temperature of 55°C, and reaction time of 269 h.
