Three-dimensional flowerlike α-Ni（OH）2 nanostructures were successfully synthesized by the microwave-assisted reflux as short as 30 rain. The crystalline structure and morphology of the products were characterized ...Three-dimensional flowerlike α-Ni（OH）2 nanostructures were successfully synthesized by the microwave-assisted reflux as short as 30 rain. The crystalline structure and morphology of the products were characterized by X-ray diffraction, N2 adsorption-desorption isotherms, field emission scanning electron microscopy, and transmission electron microscopy. The α-Ni（OH）2 nanostructure shows a large surface area of 173 m2 g-1 and narrow mesopore distribution. The electrochemical properties of the as-prepared α-Ni（OH）2 as an electrode material for supercapacitor were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in 6 mol/L KOH electrolyte. The α-Ni（OH）2 nanostructure shows a maximum specific capacitance of 2030 F g-1 at a current density of 1 A g-1 and exhibits excellent rate capability. These results suggest that it is a promising electrode material for supercapacitor application.展开更多
Co3O4 hollow spheres assembled from nanoparticles have been successfully synthesized by a one-pot hydrothermal carbonization and calcination method. In this method, carbon spheres obtained through hydrothermal carboni...Co3O4 hollow spheres assembled from nanoparticles have been successfully synthesized by a one-pot hydrothermal carbonization and calcination method. In this method, carbon spheres obtained through hydrothermal carbonization at a low temperature of 140 ℃ are used as sacrificial templates. The carbonization process was monitored by Fourier transform infrared spectroscopy （FT-IR） and Raman spectroscopy. Both the carbon sphere soft templates and the NH3 released from hexamethylenetetramine play key roles in the formation of these novel hollow structures. The formation of the Co3O4 hollow spheres using hydrothermal carbon spheres as templates can be attributed to the synergetic effect of metal ion adsorption and heterogeneous nucleation of Co（OH）2, which is different from the traditional adsorption theory. The as-obtained Co3O4 hollow microspheres exhibit excellent cycling performance and good rate capacity when used as electrode materials in supercapacitors, which can be attributed to the small particle size of Co3O4 and the sufficient space available to interact with the electrolytes. This facile strategy may be extended to synthesize other metal oxide hollow spheres, which may find application in sensors and catalysts due to their unique structural features.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51472238)the Open Project Program of State Key Laboratory of Chemical Resource Engineering(Grant No.CRE-2014-C-102)
文摘Three-dimensional flowerlike α-Ni（OH）2 nanostructures were successfully synthesized by the microwave-assisted reflux as short as 30 rain. The crystalline structure and morphology of the products were characterized by X-ray diffraction, N2 adsorption-desorption isotherms, field emission scanning electron microscopy, and transmission electron microscopy. The α-Ni（OH）2 nanostructure shows a large surface area of 173 m2 g-1 and narrow mesopore distribution. The electrochemical properties of the as-prepared α-Ni（OH）2 as an electrode material for supercapacitor were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in 6 mol/L KOH electrolyte. The α-Ni（OH）2 nanostructure shows a maximum specific capacitance of 2030 F g-1 at a current density of 1 A g-1 and exhibits excellent rate capability. These results suggest that it is a promising electrode material for supercapacitor application.
基金This work was financially supported by the National Natural Basic Research program of China （973 Program） （No. 2010CB631303）, the National Natural Science Foundation of China （NSFC） （Nos. 51171083, 51071087, and 50971071） and the 111 Project （No. B12015）.
文摘Co3O4 hollow spheres assembled from nanoparticles have been successfully synthesized by a one-pot hydrothermal carbonization and calcination method. In this method, carbon spheres obtained through hydrothermal carbonization at a low temperature of 140 ℃ are used as sacrificial templates. The carbonization process was monitored by Fourier transform infrared spectroscopy （FT-IR） and Raman spectroscopy. Both the carbon sphere soft templates and the NH3 released from hexamethylenetetramine play key roles in the formation of these novel hollow structures. The formation of the Co3O4 hollow spheres using hydrothermal carbon spheres as templates can be attributed to the synergetic effect of metal ion adsorption and heterogeneous nucleation of Co（OH）2, which is different from the traditional adsorption theory. The as-obtained Co3O4 hollow microspheres exhibit excellent cycling performance and good rate capacity when used as electrode materials in supercapacitors, which can be attributed to the small particle size of Co3O4 and the sufficient space available to interact with the electrolytes. This facile strategy may be extended to synthesize other metal oxide hollow spheres, which may find application in sensors and catalysts due to their unique structural features.
