The silicon oxide nano-powders (SiO<sub>x</sub>-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl<sub>4</sub>) with N<sub>2</sub...The silicon oxide nano-powders (SiO<sub>x</sub>-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl<sub>4</sub>) with N<sub>2</sub> and H<sub>2</sub>. The gas-phase SiCl<sub>4</sub> was injected with H<sub>2</sub> gas into the microwave plasma torch generated by N<sub>2</sub> and air swirl gas, and then the dark brown powders were deposited on the inner wall of a quartz tube. The sample was analyzed by an X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and an X-ray diffraction (XRD). The average size and oxidation x values of synthesized SiO<sub>x</sub>-NPs were approximately 230 nm and 0.91, respectively. Furthermore, the volumetric charge capacity is 1127 mAh/g and has 89.2% retention after 100 cycles.展开更多
The effects of pH value on crystal size and optical property of zinc oxide nanoparticles prepared by chemical precipitation method were investigated.Prepared samples have been characterized by means of X-ray diffracti...The effects of pH value on crystal size and optical property of zinc oxide nanoparticles prepared by chemical precipitation method were investigated.Prepared samples have been characterized by means of X-ray diffraction,scanning electron microscopy,ultraviolet-visible spectrometer and photoluminescence spectrometer.From X-ray diffraction profile,it is found that the particle size of sample increases from 13.8 to 33 nm when the pH value of the solution was increased from 6 to 13.Microstructural study also shows that the particle size increases with pH value.Hexagonal shape of the zinc oxide nanoparticle has been confirmed by the scanning electron microscopy image.The recorded ultraviolet-visible spectrum shows excitonic absorption peaks around 381 nm.The energy gap of the prepared samples has been determined from the ultraviolet-visible absorption spectrum,effective mass model equation and Tauc＇s relation.It was found that the energy gap of the prepared samples decreases with increase in pH value.The recorded blue shift confirmed the quantum confinement effect in the prepared zinc oxide samples.Photoluminescence spectrum infers that the increase in pH value shifts the ultraviolet-visible emission but not the violet and green emissions.展开更多
文摘The silicon oxide nano-powders (SiO<sub>x</sub>-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl<sub>4</sub>) with N<sub>2</sub> and H<sub>2</sub>. The gas-phase SiCl<sub>4</sub> was injected with H<sub>2</sub> gas into the microwave plasma torch generated by N<sub>2</sub> and air swirl gas, and then the dark brown powders were deposited on the inner wall of a quartz tube. The sample was analyzed by an X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and an X-ray diffraction (XRD). The average size and oxidation x values of synthesized SiO<sub>x</sub>-NPs were approximately 230 nm and 0.91, respectively. Furthermore, the volumetric charge capacity is 1127 mAh/g and has 89.2% retention after 100 cycles.
文摘The effects of pH value on crystal size and optical property of zinc oxide nanoparticles prepared by chemical precipitation method were investigated.Prepared samples have been characterized by means of X-ray diffraction,scanning electron microscopy,ultraviolet-visible spectrometer and photoluminescence spectrometer.From X-ray diffraction profile,it is found that the particle size of sample increases from 13.8 to 33 nm when the pH value of the solution was increased from 6 to 13.Microstructural study also shows that the particle size increases with pH value.Hexagonal shape of the zinc oxide nanoparticle has been confirmed by the scanning electron microscopy image.The recorded ultraviolet-visible spectrum shows excitonic absorption peaks around 381 nm.The energy gap of the prepared samples has been determined from the ultraviolet-visible absorption spectrum,effective mass model equation and Tauc＇s relation.It was found that the energy gap of the prepared samples decreases with increase in pH value.The recorded blue shift confirmed the quantum confinement effect in the prepared zinc oxide samples.Photoluminescence spectrum infers that the increase in pH value shifts the ultraviolet-visible emission but not the violet and green emissions.
