A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nicke...A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.展开更多
A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose w...A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 ： 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time （HR^I＂） and stepwise increase of feed total organic carbon （TOC） concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m ^-3·d^-1, the TOC removal ratio, the effluent pH, and the volatile fatty acids （VFA）/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value, The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBILAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volumetric TOC loadings from 0.8 kg.m^-3.d ^-1 to 14.3 kg.m^-3.d^-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability, which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca, Mg, Al, etc. were advantageous to the formation of the granules.展开更多
This study is for investigating the direct electro-deoxidation of mixed TiO2-Mn02 powder to prepare TiMn2 alloy in molten calcium chloride. The influences of process parameters, such as sintering temperature, cell vol...This study is for investigating the direct electro-deoxidation of mixed TiO2-Mn02 powder to prepare TiMn2 alloy in molten calcium chloride. The influences of process parameters, such as sintering temperature, cell voltage, and electrolysis time, on the electrolysis process were examined to investigate the mechanism of alloy formation. The composition and morphology of the products were analyzed by XRD and SEM, respectively. The electrochemical property of TiMn2 alloy was investigated by cyclic voltammetry measurements. The results show that pure TiMn2 can be prepared by direct electrochemical reduction of mixed TiO2/Mn02 pellets at a voltage of 3.1 V in molten calcium chloride of 900 ℃ for 7 h. The electro-deoxidation proceeds from the reduction of manganese oxides to Mn, which is reduced by Ti02 or CaTiOB to form TiMn2 alloy. The cyclic voltammetry measurements using pow- der microelectTode show that the prepared TiMn2 alloy has good electrochemical hydrogen storage property.展开更多
The electrocatalytic oxidation of contraflam was investigated in alkaline solution on nickel and nickel–copper alloy modified glassy carbon electrodes(GC/Ni and GC/NiCu). We prepared these electrodes by galvanostatic...The electrocatalytic oxidation of contraflam was investigated in alkaline solution on nickel and nickel–copper alloy modified glassy carbon electrodes(GC/Ni and GC/NiCu). We prepared these electrodes by galvanostatic deposition and the surface morphologies and compositions of electrodes were determined by energy-dispersive X-ray(EDX) and scanning electron microscopy(SEM). Cyclic voltammetry and chronoamperometric methods were employed to characterize the oxidation process and its kinetics. Voltammetric studies exhibit one pair of well-defined redox peaks, which is ascribed to the redox process of the nickel and followed by the greatly enhanced current response of the anodic peak in the presence of contraflam and a decrease in the corresponding cathodic current peak. This indicates that the immobilized redox mediator on the electrode surface was oxidized contraflam via an electrocatalytic mechanism. The catalytic currents increased linearly with the concentration of contraflam in the range of 0.25– 1.5 mmol/L. The anodic peak currents were linearly proportional to the square root of scan rate. This behaviour is the characteristic of a diffusion-controlled process. The determination of contraflam in capsules is applied satisfactorily by modified electrode.展开更多
Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium ch...Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium chloride （NaCl） solutions by cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS）, rotating disk electrode （RDE） and rotating ring-disk electrode （RRDE）. The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3.5% NaCl solution contains three reactions： dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction （ORR） is - 0.85 V vs Ag/AgCl, 3 molL^-1 KCI. The EIS results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, i.e., dissolved oxygen reduced to water.展开更多
Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the sample...Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that： Supercapacitors based on the sample AC-3 have low Equivalent series resistanceb （ESR） and excellent power property.展开更多
基金Project(KJ2012A045) supported by the Natural Science Foundation of Education Commission of Anhui Province,China
文摘A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.
基金Supported by the National Natural Science Foundation of China （No.50278036）, the Natural Science Foundation of Guangdong Province （No.04105951） and the National High Technology Research and Development Program of China （No.2006AA06Z378）.
文摘A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 ： 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time （HR^I＂） and stepwise increase of feed total organic carbon （TOC） concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m ^-3·d^-1, the TOC removal ratio, the effluent pH, and the volatile fatty acids （VFA）/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value, The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBILAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volumetric TOC loadings from 0.8 kg.m^-3.d ^-1 to 14.3 kg.m^-3.d^-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability, which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca, Mg, Al, etc. were advantageous to the formation of the granules.
基金Supported by the National Natural Science Foundation of China(51201058)the Natural Science Foundation of Hebei Province(E2014209009)
文摘This study is for investigating the direct electro-deoxidation of mixed TiO2-Mn02 powder to prepare TiMn2 alloy in molten calcium chloride. The influences of process parameters, such as sintering temperature, cell voltage, and electrolysis time, on the electrolysis process were examined to investigate the mechanism of alloy formation. The composition and morphology of the products were analyzed by XRD and SEM, respectively. The electrochemical property of TiMn2 alloy was investigated by cyclic voltammetry measurements. The results show that pure TiMn2 can be prepared by direct electrochemical reduction of mixed TiO2/Mn02 pellets at a voltage of 3.1 V in molten calcium chloride of 900 ℃ for 7 h. The electro-deoxidation proceeds from the reduction of manganese oxides to Mn, which is reduced by Ti02 or CaTiOB to form TiMn2 alloy. The cyclic voltammetry measurements using pow- der microelectTode show that the prepared TiMn2 alloy has good electrochemical hydrogen storage property.
基金financial assistance from Tehran University of Medical Sciences,Tehran,Iran
文摘The electrocatalytic oxidation of contraflam was investigated in alkaline solution on nickel and nickel–copper alloy modified glassy carbon electrodes(GC/Ni and GC/NiCu). We prepared these electrodes by galvanostatic deposition and the surface morphologies and compositions of electrodes were determined by energy-dispersive X-ray(EDX) and scanning electron microscopy(SEM). Cyclic voltammetry and chronoamperometric methods were employed to characterize the oxidation process and its kinetics. Voltammetric studies exhibit one pair of well-defined redox peaks, which is ascribed to the redox process of the nickel and followed by the greatly enhanced current response of the anodic peak in the presence of contraflam and a decrease in the corresponding cathodic current peak. This indicates that the immobilized redox mediator on the electrode surface was oxidized contraflam via an electrocatalytic mechanism. The catalytic currents increased linearly with the concentration of contraflam in the range of 0.25– 1.5 mmol/L. The anodic peak currents were linearly proportional to the square root of scan rate. This behaviour is the characteristic of a diffusion-controlled process. The determination of contraflam in capsules is applied satisfactorily by modified electrode.
基金supported by the National Natural Science Foundation of China ( Grant No 40876041)Science and Technology Basic Research Program of Qingdao (Grant No 09-1-3-16-jch)the National Key Technology Research and Development Program of China (Grant No 2007 BAB27B01)
文摘Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium chloride （NaCl） solutions by cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS）, rotating disk electrode （RDE） and rotating ring-disk electrode （RRDE）. The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3.5% NaCl solution contains three reactions： dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction （ORR） is - 0.85 V vs Ag/AgCl, 3 molL^-1 KCI. The EIS results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, i.e., dissolved oxygen reduced to water.
文摘Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that： Supercapacitors based on the sample AC-3 have low Equivalent series resistanceb （ESR） and excellent power property.
