A new method based on electrochemical double layer model is put forward to calculate edge level at the semiconductor solution interface. Fermi level and edge level of semiconductor in solution are required to build en...A new method based on electrochemical double layer model is put forward to calculate edge level at the semiconductor solution interface. Fermi level and edge level of semiconductor in solution are required to build energy band model. Edge level of semiconductor is very difficult to be measured directly in the process of sulfide flotation, so it is necessary to predict the value of edge level from theory. Then the theoretical prediction of edge level is simplified by means of zeta potential, which is easy to be measured and often used in flotation. According to this model, parameters of flotation solution, such as zeta potential, ion strength, Dybe length and electrode potential etc, and parameters of semiconductors properties, such as band gap, work function, type of semiconductor etc, are connected organically. The electron density and hole density in the mineral surface layer are depended on the values of surface potential barrier related to edge level; in addition, the dynamic process of semiconductor electrode is related to the change of surface potential barrier. All of them play an important role in the process of sulfide flotation.展开更多
Graphene oxide (GO) film was electrochemically reduced by a cyclic voltammetry technique in 6 mol L-1 KOH aqueous solution.Electrochemically reduced graphene oxide (ER-GO) film was characterized by X-ray diffraction,X...Graphene oxide (GO) film was electrochemically reduced by a cyclic voltammetry technique in 6 mol L-1 KOH aqueous solution.Electrochemically reduced graphene oxide (ER-GO) film was characterized by X-ray diffraction,X-ray photoelectron spectroscopy,atomic force microscopy,and Raman spectroscopy.The oxygen content (with the O/C atomic ratio of 1.29%) was significantly decreased after electrochemical reduction.The ER-GO film exhibited a specific capacitance of 152 F g-1 at the current density of 5 A g-1 and a good rate capability.Furthermore,the ER-GO film showed an excellent cycling ability.The capacitance retention remained 99% after 3000 cycles at the current density of 10 A g-1.展开更多
Multi-walled carbon nanombes with homogeneous diameters （40 - 60 nm）, produced by chemical vapor deposition of hydrocarbon gas, are purified by nitric acids. Infrared and Raman studies indicate that oxygen containin...Multi-walled carbon nanombes with homogeneous diameters （40 - 60 nm）, produced by chemical vapor deposition of hydrocarbon gas, are purified by nitric acids. Infrared and Raman studies indicate that oxygen containing surface groups, which are predominately carboxylic, phenolic and lactonic groups, are introduced into purified carbon nanotubes. Then three kinds of block-form porous tablets of carbon nanotubes are fabricated as electrodes in electrochemical double-layer capacitors. Using mounded mixture comprising carbon nanotubes and binder powders provides these tablets. Comparison of the effect of different processing on the structural performance of the capacitors is specifically investigated. Using chemically treated electrodes, electrochemical double-layer capacitors with a specific capacitance of about 33 F/g are obtained with 38 wt % H2SO4 as the electrolyte.展开更多
文摘A new method based on electrochemical double layer model is put forward to calculate edge level at the semiconductor solution interface. Fermi level and edge level of semiconductor in solution are required to build energy band model. Edge level of semiconductor is very difficult to be measured directly in the process of sulfide flotation, so it is necessary to predict the value of edge level from theory. Then the theoretical prediction of edge level is simplified by means of zeta potential, which is easy to be measured and often used in flotation. According to this model, parameters of flotation solution, such as zeta potential, ion strength, Dybe length and electrode potential etc, and parameters of semiconductors properties, such as band gap, work function, type of semiconductor etc, are connected organically. The electron density and hole density in the mineral surface layer are depended on the values of surface potential barrier related to edge level; in addition, the dynamic process of semiconductor electrode is related to the change of surface potential barrier. All of them play an important role in the process of sulfide flotation.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KJCX2-YW-W26)Beijing Municipal Science and Technology Commission(Z111100056011007)the National Natural Science Foundation of China(21001103and51025726)
文摘Graphene oxide (GO) film was electrochemically reduced by a cyclic voltammetry technique in 6 mol L-1 KOH aqueous solution.Electrochemically reduced graphene oxide (ER-GO) film was characterized by X-ray diffraction,X-ray photoelectron spectroscopy,atomic force microscopy,and Raman spectroscopy.The oxygen content (with the O/C atomic ratio of 1.29%) was significantly decreased after electrochemical reduction.The ER-GO film exhibited a specific capacitance of 152 F g-1 at the current density of 5 A g-1 and a good rate capability.Furthermore,the ER-GO film showed an excellent cycling ability.The capacitance retention remained 99% after 3000 cycles at the current density of 10 A g-1.
基金Project supported by National High-Technology Research and De-velopment Program(Grant No .863 -2002AA302302)
文摘Multi-walled carbon nanombes with homogeneous diameters （40 - 60 nm）, produced by chemical vapor deposition of hydrocarbon gas, are purified by nitric acids. Infrared and Raman studies indicate that oxygen containing surface groups, which are predominately carboxylic, phenolic and lactonic groups, are introduced into purified carbon nanotubes. Then three kinds of block-form porous tablets of carbon nanotubes are fabricated as electrodes in electrochemical double-layer capacitors. Using mounded mixture comprising carbon nanotubes and binder powders provides these tablets. Comparison of the effect of different processing on the structural performance of the capacitors is specifically investigated. Using chemically treated electrodes, electrochemical double-layer capacitors with a specific capacitance of about 33 F/g are obtained with 38 wt % H2SO4 as the electrolyte.
