Ordered mesoporous carbon nanospheres with uniformly penetrating channels have been successfully synthesized by a nanocasting method using mesoporous silica as a template. The ordered mesoporous carbon nanospheres were investigated as electrode materials for supercapacitors via high-resolution transmission electron microscopy, nitrogen adsorption and desorption isotherms and a variety of electrochemical testing techniques. The electrodes with ordered mesoporous carbon nanospheres prepared by coating method exhibited good rate capability and reversibility at high scan rates in electrochemical performances. Ordered mesoporous carbon nanosphere electrode with specific surface area of 904 m2/g maintained a stable specific capacitance of 210 F g-1under specific current of 0.1 A g-1for 500 cycles of charge/discharge.
Abstract. Green light emitting Mn2+-doped Zn2SiO4 (Zn2SiO4:Mn2+) phosphor nano-particles were synthesized by sol-gel method combined with a furnace firing from the sol-gel solution made with ZnO, MnCO3 and tetraethoxysilan. The influences of annealing temperatures on the microstructures and photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were investigated. The structural details of the phosphors were examined through XRD and SEM. The photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were characterized by excitation and emission spectra. The results indicate that the XRD patterns of the Zn2SiO4:Mn2+ phosphors exhibit a willemite structure (-Zn2SiO4). Green photoluminescence whose emission peak is located at 525 nm were observed from the synthesized phosphor particles under UV excitation. The photoluminescent mechanisms of the Zn2SiO4:Mn2+ phosphors were discussed.
High quality graphene sheets (GSs) were prepared from natural graphite by oxidation, rapid thermal expansion and ultrasonic treatment. The morphology and structure of GSs were systematically investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier tansform infrared spectroscopy (FT-IR) and Raman spectroscopy. It was found that the GSs electrode used in lithium-ion battery (LIB) exhibited a relatively high reversible capacity of 902 mA h/g at a current density of 50 mA/g. After 50 cycles, the reversible capacity was still kept at 734 mA h/g.
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