Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficienc...Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficiency and pollution removal mechanism of the FeMnO were approached. Results show that the main compositions of the FeMnO are δ-manganese dioxide and ferric hydroxide. The specific surface area is about 146.22 m^2/g. The FeMnO contains rich hydroxyl with extremely strong adsorption action and chemical adsorption activity. The zero charge point of the oxide in pure water is about 8.0 of pH value. Under neutral pH value conditions, the FeMnO particle surface carried positive charges. The FeMnO particles are quasi-spherical micro-particles with irregular sizes adjoined each other to form net construction. Phosphorus removal efficiency of the FeMnO is remarkable, the total dissoluble phosphorus of settled water can be reduced below detecting level（0.3 μtg/L） at a FeMnO dosage of 6 mg/L, and total phosphorus below detecting level at a FeMnO dosage of 10 mg/L, for water samples containing total phos- phorus of 1281.70 μg/L and total dissoluble phosphorus of 1187.91 μtg/L. The mechanism of effective coagulation for phosphorus removal is combined results of multiple actions of adsorption, charge neutralization, adsorption/bridging and so on.展开更多
This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydroth...This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy reveal that MnO2 nanosheets homogeneously grow onto the surface of micro-HC to form a loose-packed microstructure. The quantity of MnO2 required in the electrode layer has thereby been reduced significantly, and higher specific capacitances have been achieved. The micro-HC/nano-MnO2 electrode presents a high capacitance of 239.0 F g-1 at a current density of 5 m A cm-2, which is a strong promise for high-rate electrochemical capacitive energy storage applications.展开更多
Thanks to low cost,high safety,and large energy density,aqueous zinc-ion batteries have attracted tremendous interest worldwide.However,it remains a challenge to develop high-performance cathode materials with an appr...Thanks to low cost,high safety,and large energy density,aqueous zinc-ion batteries have attracted tremendous interest worldwide.However,it remains a challenge to develop high-performance cathode materials with an appropriate method that is easy to realize massive production.Herein,we use a molten salt method to synthesize nanostructured manganese oxides.The crystalline phases of the manganese oxides can be tuned by changing the amount of reduced graphene oxide added to the reactant mixture.It is found that the α-MnO_(2)/Mn_(2)O_(3) nanocomposite with the largest mass ratio of Mn_(2)O_(3) delivers the best electrochemical performances among all the products.And its rate capability and cyclability can be significantly improved by modifying the Zn anode with carbon black coating and nanocellulose binder.In this situation,the nanocomposite can deliver high discharging capacities of 322.1 and 213.6 mAh g^(-1) at 0.2 and 3 Ag^(-1),respectively.After 1000 cycles,it can retain 86.2% of the capacity at the 2 nd cycle.Thus,this nanocomposite holds great promise for practical applications.展开更多
This article reported the electrochemical performance of a novel cabon microsphere/MnO2nanosheets(CMS/MnO2) composite prepared by a in situ self-limiting deposition method under hydrothermal condition. The results of ...This article reported the electrochemical performance of a novel cabon microsphere/MnO2nanosheets(CMS/MnO2) composite prepared by a in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy(SEM) and transmission electron microscopy(TEM) revealed that MnO2nanosheets homogeneously grew onto the surface of CMS to form a loose-packed and dandelion-like core/shell microstructure. The unique microstructure plays a basic role in electrochemical accessibility of electrolyte to MnO2active material and a fast diffusion rate within the redox phase. The results of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrometry indicated that the prepared CMS/MnO2composite presented high capacitance of 181 F g-1and long cycle life of 61% capacity retention after 2000 charge/discharge cycles in 1 mol/L Na2SO4solution, which show strong promise for high-rate electrochemical capacitive energy storage applications.展开更多
In this paper, a Fe-Mn-Al-C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning e...In this paper, a Fe-Mn-Al-C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning electron microscope （SEM）, the electron microprobe （EPMA） and the X-ray diffraction （XRD）, the high-temperature oxidation behavior microstructure and the phase compositions of this steel in air at 600-1,000 ℃ for 8 h have been studied. The results show that in the whole oxidation temperature range, there are three distinct stages in the mass gain curves at temperature higher than 800 ℃ and the oxidation process can be divided into two stages at temperature lower than 800 ℃. At the earlier stage the gain rate of the weight oxidized in temperature range of 850 ℃ to 1,000 ℃ are extremely lower. The oxidation products having different surface microstructures and phase compositions were produced in oxidation reaction at different temperatures. The phase compositions of oxide scale formed at 1,000 ℃ are composed of Fe and Mn oxide without Cr. However, protective film of Cr oxide with complicated structure can be formed when the oxidation temperature is lower than 800 ℃.展开更多
基金Supported by National Natural Science Foundation of China(Nos.50378004 and 50678007)Beijing Natural Science Foun-dation(No.8082009)+1 种基金Science & Technology Development Programme of Beijing Municipal Commission of Education (No.KM200610005025)Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality(No. 05004014200701).
文摘Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficiency and pollution removal mechanism of the FeMnO were approached. Results show that the main compositions of the FeMnO are δ-manganese dioxide and ferric hydroxide. The specific surface area is about 146.22 m^2/g. The FeMnO contains rich hydroxyl with extremely strong adsorption action and chemical adsorption activity. The zero charge point of the oxide in pure water is about 8.0 of pH value. Under neutral pH value conditions, the FeMnO particle surface carried positive charges. The FeMnO particles are quasi-spherical micro-particles with irregular sizes adjoined each other to form net construction. Phosphorus removal efficiency of the FeMnO is remarkable, the total dissoluble phosphorus of settled water can be reduced below detecting level（0.3 μtg/L） at a FeMnO dosage of 6 mg/L, and total phosphorus below detecting level at a FeMnO dosage of 10 mg/L, for water samples containing total phos- phorus of 1281.70 μg/L and total dissoluble phosphorus of 1187.91 μtg/L. The mechanism of effective coagulation for phosphorus removal is combined results of multiple actions of adsorption, charge neutralization, adsorption/bridging and so on.
基金supported by the National Natural Science Foundation of China (51203071, 51363014 and 51362018)China Postdoctoral Science Foundation (2014M552509)+1 种基金the Key Project of Chinese Ministry of Education (212183)the Natural Science Funds for Distinguished Young Scholars of Gansu Province (1111RJDA012)
文摘This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets(micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy reveal that MnO2 nanosheets homogeneously grow onto the surface of micro-HC to form a loose-packed microstructure. The quantity of MnO2 required in the electrode layer has thereby been reduced significantly, and higher specific capacitances have been achieved. The micro-HC/nano-MnO2 electrode presents a high capacitance of 239.0 F g-1 at a current density of 5 m A cm-2, which is a strong promise for high-rate electrochemical capacitive energy storage applications.
基金funded by the National Natural Science Foundation of China(No.51902165)the Natural Science Foundation of Jiangsu Province(No.BK20170917)+2 种基金the Scientific Research Foundation for High-Level Talents of Nanjing Forestry University(No.GXL2016023)the Program of High-Level Talents in Six Industries of Jiangsu Province(No.XCL-040)the Jiangsu Specially-Appointed Professor Program。
文摘Thanks to low cost,high safety,and large energy density,aqueous zinc-ion batteries have attracted tremendous interest worldwide.However,it remains a challenge to develop high-performance cathode materials with an appropriate method that is easy to realize massive production.Herein,we use a molten salt method to synthesize nanostructured manganese oxides.The crystalline phases of the manganese oxides can be tuned by changing the amount of reduced graphene oxide added to the reactant mixture.It is found that the α-MnO_(2)/Mn_(2)O_(3) nanocomposite with the largest mass ratio of Mn_(2)O_(3) delivers the best electrochemical performances among all the products.And its rate capability and cyclability can be significantly improved by modifying the Zn anode with carbon black coating and nanocellulose binder.In this situation,the nanocomposite can deliver high discharging capacities of 322.1 and 213.6 mAh g^(-1) at 0.2 and 3 Ag^(-1),respectively.After 1000 cycles,it can retain 86.2% of the capacity at the 2 nd cycle.Thus,this nanocomposite holds great promise for practical applications.
基金supported by the National Natural Science Foundation of China(No.51363014,51362018,51203071 and 21163010)the Key Project of Chinese Ministry of Education(No.212183)the Natural Science Funds for Distinguished Young Scholars of Gansu Province(No1111RJDA012)
文摘This article reported the electrochemical performance of a novel cabon microsphere/MnO2nanosheets(CMS/MnO2) composite prepared by a in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy(SEM) and transmission electron microscopy(TEM) revealed that MnO2nanosheets homogeneously grew onto the surface of CMS to form a loose-packed and dandelion-like core/shell microstructure. The unique microstructure plays a basic role in electrochemical accessibility of electrolyte to MnO2active material and a fast diffusion rate within the redox phase. The results of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrometry indicated that the prepared CMS/MnO2composite presented high capacitance of 181 F g-1and long cycle life of 61% capacity retention after 2000 charge/discharge cycles in 1 mol/L Na2SO4solution, which show strong promise for high-rate electrochemical capacitive energy storage applications.
基金supported by the National High Technology Research and Development Program of China (No. 2012AA03A508)the National Natural Science Foundation of China (No. 51271051)
文摘In this paper, a Fe-Mn-Al-C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning electron microscope （SEM）, the electron microprobe （EPMA） and the X-ray diffraction （XRD）, the high-temperature oxidation behavior microstructure and the phase compositions of this steel in air at 600-1,000 ℃ for 8 h have been studied. The results show that in the whole oxidation temperature range, there are three distinct stages in the mass gain curves at temperature higher than 800 ℃ and the oxidation process can be divided into two stages at temperature lower than 800 ℃. At the earlier stage the gain rate of the weight oxidized in temperature range of 850 ℃ to 1,000 ℃ are extremely lower. The oxidation products having different surface microstructures and phase compositions were produced in oxidation reaction at different temperatures. The phase compositions of oxide scale formed at 1,000 ℃ are composed of Fe and Mn oxide without Cr. However, protective film of Cr oxide with complicated structure can be formed when the oxidation temperature is lower than 800 ℃.
