The nano-MnO2 as active electrode material for supercapacitor was synt hesized by solid-state reaction between KMnO4 and manganese acetate at room temp erature. The products annealed at 100 ℃ and 200 ℃ were characte...The nano-MnO2 as active electrode material for supercapacitor was synt hesized by solid-state reaction between KMnO4 and manganese acetate at room temp erature. The products annealed at 100 ℃ and 200 ℃ were characterized by XRD an d TEM. The results showed the sample annealed at 100 ℃ was poorly crystallized phase with an average grain size of <20 nm. Electrochemical performances of mang anese oxide electrode were investigated by cyclic voltammetry and constant curre nt charge/discharge. The manganese oxide electrode annealed at 100 ℃ in 1 mol· L-1 Na2SO4 aqueous electrolyte exhibited excellent capacitive behavior between - 0.2 and +0.8 V (vs SCE). By 5 mA and 10 mA constant current charge/discharge, th e nano-MnO2 annealed at 100 ℃ can provide a specific capacitance of 158.5 F·g- 1 and 151.2 F·g-1, respectively.展开更多
The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal so...The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.展开更多
Potentiodynamic polarisation, potential-time measurements, X-ray diffraction (XRD) and infrared spectroscopy (IR) have been used to investigate the effect of different concentrations of Na2SO4 in the absence and prese...Potentiodynamic polarisation, potential-time measurements, X-ray diffraction (XRD) and infrared spectroscopy (IR) have been used to investigate the effect of different concentrations of Na2SO4 in the absence and presence of NaCI, on the corrosion of Cu-alloy. The electrochemical measurements showed that the increase of Na2SO4 concentration led to increase the corrosion current density of Cu alloy and vice versa. The presence of NaCI shifted the potential to more cathodic potential, which had a great influence on the protectiveness of the Cu oxide layer formed on the surface in presence of Na2SO4. The spectrometric measurements indicated the constituents of the film formed on the alloy surface were mainly Cu2O, in addition to the oxides, NiO and Fe2O3, which were traced by XRD analysis.展开更多
文摘The nano-MnO2 as active electrode material for supercapacitor was synt hesized by solid-state reaction between KMnO4 and manganese acetate at room temp erature. The products annealed at 100 ℃ and 200 ℃ were characterized by XRD an d TEM. The results showed the sample annealed at 100 ℃ was poorly crystallized phase with an average grain size of <20 nm. Electrochemical performances of mang anese oxide electrode were investigated by cyclic voltammetry and constant curre nt charge/discharge. The manganese oxide electrode annealed at 100 ℃ in 1 mol· L-1 Na2SO4 aqueous electrolyte exhibited excellent capacitive behavior between - 0.2 and +0.8 V (vs SCE). By 5 mA and 10 mA constant current charge/discharge, th e nano-MnO2 annealed at 100 ℃ can provide a specific capacitance of 158.5 F·g- 1 and 151.2 F·g-1, respectively.
基金Supported by the National Key Research and Development Program of China(2016YFB0600504)
文摘The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.
文摘Potentiodynamic polarisation, potential-time measurements, X-ray diffraction (XRD) and infrared spectroscopy (IR) have been used to investigate the effect of different concentrations of Na2SO4 in the absence and presence of NaCI, on the corrosion of Cu-alloy. The electrochemical measurements showed that the increase of Na2SO4 concentration led to increase the corrosion current density of Cu alloy and vice versa. The presence of NaCI shifted the potential to more cathodic potential, which had a great influence on the protectiveness of the Cu oxide layer formed on the surface in presence of Na2SO4. The spectrometric measurements indicated the constituents of the film formed on the alloy surface were mainly Cu2O, in addition to the oxides, NiO and Fe2O3, which were traced by XRD analysis.
