Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ...Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3＋ ions could accelerate the bioleaching,while the concentration of additional Fe^3＋ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3＋ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3＋ ions are added.展开更多
The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon t...The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon testing, electrochemical measurement of open-circuit potential and linear sweep voltammetry. The results reveal that the existence of F-and Cl-ions in the simulated treated water accelerate the corrosion rate of Q235 A steel. The corrosion rate reaches maximum with F-concentration of 50 mg/L, Cl-concentration of 200 mg/L, respectively. However, Q235 A steel would passivate when an applied potential is added to the system. Meanwhile, the initiating passive potential becomes positive with F-, Cl-concentration increasing. There is a little influence of F-, Cl-concentration on the initiating passivation current density. Therefore, it is necessary to control F-, Cl-concentration in the treated water when it is recycled by the pipelines made of Q235 A steel.展开更多
Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder ...Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric and differential-thermogravimetric analysis(TG-DTA) and energy dispersive X-ray spectrometry(EDS) techniques,showing uniform nanowire shape of LiFePO4/C with a diameter of 80-150 nm and a length of several microns.The heat-treated LiFePO4/C nanowires show excellent electrochemical properties of specific discharge capacity,rate capacity and cycling stability.In particular,the LiFePO4/C nanowires heat-treated at 400 °C show preferable first discharge specific capacity of 161 mA·h/g at 0.1C rate,while the voltage platform is 3.4 V and the first discharge specific capacity is 93 mA·h/g at 20C rate.The specific capacity retention is 98% after 50 cycles at 5C rate.展开更多
A novel copper（Ⅱ） complex derived from 1,4,7-triazacyclononane[CuL]_2（PF_6）_3×MeCN×H_2 O was synthesized and crystallographically characterized {L = 1,4-bis（2-carbamoylethyl）-7-benzimidazole-2-yl-meth...A novel copper（Ⅱ） complex derived from 1,4,7-triazacyclononane[CuL]_2（PF_6）_3×MeCN×H_2 O was synthesized and crystallographically characterized {L = 1,4-bis（2-carbamoylethyl）-7-benzimidazole-2-yl-methyl-1,4,7-triazacyclononane}. It crystallizes in triclinic, space group P1, with a = 13.2425（13）, b = 14.0807（15）, c = 17.6798（18）, α = 86.296（2）, β = 72.773（2）, γ= 68.905（2）o, V = 2934.5（5）A^3, Z = 2, D_c = 1.611 g/m^3, F（000） = 1456, M_r = 1423.09, m = 0.920 mm^-1. The final R = 0.0671 and wR = 0.1874 for 6501 observed reflections with I 〉 2σ（I）. The structural analysis shows that the complex cation（[CuL]_2^3＋） was formed by two complex cations, namely（[CuL^3]^2＋） and [CuL_（-H）~3]~＋） through a hydrogen bond. In each complex cation, the Cu（Ⅱ） lies in a distorted square pyramidal geometry. The redox behavior was studied by cyclic voltammetry（CV） in aqueous solution which indicates a reversible one electron redox reaction. The result of UV absorption, ethidium bromide（EB） fluorescence spectra indicated that the complex binds to CT-DNA in an intercalative mode. Superoxide dismutase（SOD） activity of the complex was determined by photoreduction of NBT, and the value of IC_（50） is 5.22 μmol·L^-1.展开更多
A novel Schiff-base compound based on ferrocene C18H17OFeN3 （1） has been synthesized and characterized by X-ray diffraction. The title compound crystallizes in monoclinic, space group P21/c with a = 19.2343（17）, b...A novel Schiff-base compound based on ferrocene C18H17OFeN3 （1） has been synthesized and characterized by X-ray diffraction. The title compound crystallizes in monoclinic, space group P21/c with a = 19.2343（17）, b = 10.5084（9）, c = 7.9373（7） A, β = 97.7740°, Z = 4, V = 1589.6（2） A^3, Dc = 1.451 g/cm^3, μ（MoKα） = 0.956 mm^-1, F（000） = 720, the final R = 0.0343 and wR = 0.0973 for 2759 observed reflections （I 〉 2σ（I））. Electrochemical measurements exhibit that compound 1 undergoes a reversible one-electron redox process.展开更多
A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electroc...A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electrochemical properties of the porphyrins were studied. The authors found that there was moderate electronic communication between the two porphyrin rings in the nanometer porphyrin dimer.展开更多
Mesoporous aluminum-doped titanium dioxide(Al-TiO2) materials with high specific surface areas were prepared via a solid-state reaction route.The properties of these materials were characterized by X-ray diffraction(X...Mesoporous aluminum-doped titanium dioxide(Al-TiO2) materials with high specific surface areas were prepared via a solid-state reaction route.The properties of these materials were characterized by X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),N2 absorption-desorption,ultraviolet visible light spectroscopy(UV-Vis) and electrochemical spectroscopy.The results show that the mesoporous structure of the product with ethanol is composed of anatase laced crystal walls with amorphous grain boundaries formed gradually by degradation.Compared with those without ethanol,these samples possess larger crystallite size since ethanol decreases the pore size at higher temperature.With the increase of ethanol amount,however,the crystallite size will grow.The amorphous grain boundaries in the mesoporous material,with a large impedance and low incidental cyclic potential,are difficult to effectively degrade and the phase transformation temperature is changed from 500 to 550℃.The growth rate of Al-TiO2 crystallites that obeys the quadratic polynomial equation may be controlled.展开更多
A supramolecular compound（H2en）2[Cu（en）2（H3O）2][Mo8O28]（en=ethylenediamine） was hydrothermally prepared and confirmed by elemental analysis and TG analysis.Single-crystal X-ray analysis reveals that the crysta...A supramolecular compound（H2en）2[Cu（en）2（H3O）2][Mo8O28]（en=ethylenediamine） was hydrothermally prepared and confirmed by elemental analysis and TG analysis.Single-crystal X-ray analysis reveals that the crystal crystallizes in the triclinic system,space group P1 with a=9.4635（4）,b=9.8645（5）,c=10.9794（5）A,α=69.2050（10）,β=72.3730（10）,γ=78.4510（10）o,Mr=1559.55,V=908.24（7）A^3,Z=1,Dc=2.851 g/m^3,F（000）=749,μ=3.350 mm^-1,S=1.000,the final R=0.0217 and wR=0.0567.The compound consists of（H2en）^2＋,[Mo8O28]^8-anion and [Cu（en）2（H3O）2]^2＋ cations and constructs a 3D supramolecular structure through hydrogen bonds between the nitrogen atoms from en of [Cu（en）2（H3O）2]^4＋ fragments and the terminal oxygen atoms from the [Mo8O28]^8-polyoxoanions.The electrochemical behavior of this compound has been studied in detail based on a solid bulk modified carbon paste electrode of compound（CPE）.展开更多
In order to confirm the optimal Li content of Li-rich Mn-based cathode materials(a fixed mole ratio of Mn to Ni to Co is0.6:0.2:0.2),Li1+x(Mn0.6Ni0.2Co0.2)1-xO2(x=0,0.1,0.2,0.3)composites were obtained,which had a typ...In order to confirm the optimal Li content of Li-rich Mn-based cathode materials(a fixed mole ratio of Mn to Ni to Co is0.6:0.2:0.2),Li1+x(Mn0.6Ni0.2Co0.2)1-xO2(x=0,0.1,0.2,0.3)composites were obtained,which had a typical layered structure with R3m and C2/m space group observed from X-ray powder diffraction(XRD).Electron microscopy micrograph(SEM)reveals that the particle sizes in the range of0.4-1.1μm increase with an increase of x value.Li1.2(Mn0.6Ni0.2Co0.2)0.8O2sample delivers a larger initial discharge capacity of275.7mA·h/g at the current density of20mA/g in the potential range of2.0-4.8V,while Li1.1(Mn0.6Ni0.2Co0.2)0.9O2shows a better cycle performance with a capacity retention of93.8%at0.2C after50cycles,showing better reaction kinetics of lithium ion insertion and extraction.展开更多
The title compound 5,10,15,20-tetrakis（4-chlorophenyl）porphyrin was synthesized and structurally characterized by X-ray single-crystal diffraction method. Crystal data： triclinic, space group P, Z=1, C50H32Cl4N4, M...The title compound 5,10,15,20-tetrakis（4-chlorophenyl）porphyrin was synthesized and structurally characterized by X-ray single-crystal diffraction method. Crystal data： triclinic, space group P, Z=1, C50H32Cl4N4, Mr=830.60, a=6.4316（13）, b=11.322（2）, c=13.833（3） , α =91.44（3）, β=91.06（2）, γ=92.67（3）°, V=1005.7（3）3 , Dc=1.371 g/cm3 , μ（MoKα）=0.34 mm-1 , F（000）=428, R=0.0563 and wR=0.0867 for 2712 observed reflections with I 〉 2σ（I）. X-ray analysis reveals the phenyl rings and the pyrrole rings are not in the same plane. The dihedral angles between adjacent phenyl rings and pyrrole rings are 66.1 and 66.8°, respectively.展开更多
A new 3D Ag（I） coordination polymer, [Ag8（btc）2（bpp）2]n（1, H4btc = biphenyl- 2,2ˊ,4,4ˊ-tetracarboxylic acid, bpp = 1,2-bis（4-pyridyl）propane）, has been hydrothermally synthesi- zed and characterized by sin...A new 3D Ag（I） coordination polymer, [Ag8（btc）2（bpp）2]n（1, H4btc = biphenyl- 2,2ˊ,4,4ˊ-tetracarboxylic acid, bpp = 1,2-bis（4-pyridyl）propane）, has been hydrothermally synthesi- zed and characterized by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. Complex 1 crystallizes in the triclinic system, space group P1 with a = 13.4899（8）, b = 13.4928（8）, c = 16.4575（10） , α = 102.7640（10）, β = 108.8100（10）, γ = 101.4940（10）°, V = 2644.1（3） 3, Z = 2, Dc = 2.401 Mg·m-3, μ = 2.978 mm-1, F（000） = 1840, the final R = 0.0481 and wR = 0.0955 for 6794 observed reflections with I 〉 2σ（I）. Complex 1 features a 3D framework formed by Ag（I）-carboxylate chains containing [Ag16（COO）16] secondary building block. Furthermore, thermal stability and electrochemical property of 1 are also investigated in detail.展开更多
One novel complex [Co（p-MBA）2（2,2＇-bipy）（H2O）]·（H2O） has been synthesized by the reaction of p-methylbenzoic acid with 2,2＇-bipyridine in the solvent mixture of water and methanol. It crystallizes in tr...One novel complex [Co（p-MBA）2（2,2＇-bipy）（H2O）]·（H2O） has been synthesized by the reaction of p-methylbenzoic acid with 2,2＇-bipyridine in the solvent mixture of water and methanol. It crystallizes in triclinic, space group P1 with a = 0.70479（14）, b = 1.1211（2）, c = 1.6718（3） nm, α = 103.806（3）, β = 90.795（3）, γ = 104.207（3）°, V= 1.2399（4） nm^3, Mr = 512.41, De= 1.373 g/cm^3, Z = 2, F（000） = 532,μ = 0.733 mm^-1, R = 0.0432 and ωR = 0.0957. The crystal structural analysis shows that the cobalt atom is coordinated with three oxygen atoms from two p-methylbenzoic acids and one water molecule and two nitrogen atoms from one 2,2＇-bipyridine, forming a distorted square-pyramidal coordination geometry. The cyclic voltammetry behavior of the complex is also reported.展开更多
Cs0.35V2O5 was successfully synthesized as cathode material for lithium secondary battery by the rheological phase reaction method from Cs2CO3 and NH4VO3. The Cs0.35V2O5/Cu composite material was prepared by the displ...Cs0.35V2O5 was successfully synthesized as cathode material for lithium secondary battery by the rheological phase reaction method from Cs2CO3 and NH4VO3. The Cs0.35V2O5/Cu composite material was prepared by the displacement reaction in CuSO4 solution using zinc powder as a reductant. The structure and electrochemical property of the so-prepared powders were characterized by means of XRD （powder X-ray diffraction） and the galvanostatic discharge-charge techniques. The results show that the electrochemical property of Cs0.35V2O5/Cu composite material is significantly improved compared to the bulk Cs0.35V2O5 material. The Cs0.35V2O5/Cu composite material exhibits the first discharge capacity as high as 164.3 mAh.g -1 in the range of 4.2-1.8V at a current rate of 10 mA.g-1 and remains at a stable discharge capacity of about 110 mAh.g-1 within 40 cycles.展开更多
Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombi...Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombic efficiency.To address the issues,cesium nitrate(CsNO3)is selected as the additive to modify the electrolyte for lithium secondary battery.Here we report electrochemical performance of lithium secondary battery with different concentration of CsNO3 as electrolyte additive.The study result demonstrates that Coulombic efficiency of Li–Cu cells and the lifetime of symmetric lithium cells contained CsNO3 additive are improved greatly.Li–Cu cell with 0.05 mol/L CsNO3 and 0.15 mol/L LiNO3 as electrolyte additive presents the best electrochemical performance,having the highest Coulombic efficiency of around 97%and the lowest interfacial resistance.With increasing the concentration of CsNO3 as electrolyte additive,the electrochemical performance of cells becomes poor.Meanwhile,the morphology of lithium deposited films with CsNO3-modified electrolyte become smoother and more uniform compared with the basic electrolyte.展开更多
As a highly promising conductive polymer material,the synthesis method,structure regulation,and performance improvement of polyaniline(PANI)are hot research topics.In this work,the radiation-induced polymerization of ...As a highly promising conductive polymer material,the synthesis method,structure regulation,and performance improvement of polyaniline(PANI)are hot research topics.In this work,the radiation-induced polymerization of aniline in HNO_(3)solution was successfully achieved at room temperature without the use of chemical oxidants.Through the analysis of the radiation chemical reactions of inorganic acids and nitrate salt solutions,the characterization of the intermediate free radicals in the irradiated systems,and the influence of the pH of the solutions on the polymerization activity and product morphologies,the radiation-induced polymerization mechanism of aniline is discussed in detail and proposed.Only at a condition of[HNO_(3)]>[aniline],i.e.,pH<2.5,PANI can be successfully obtained underγ-ray radiation.The polymerization begins with the oxidation of aniline cations to aniline cation radicals by·NO_(3)generated by radiolysis reactions,and undergoes repeated three steps of monomer free radical recombination,deprotonation,and oxidation reaction of·NO_(3),thus forming a PANI macromolecule.In addition to the polymerization reaction,the aniline units are protonated and oxidized because of the strongly acidity and oxidation of the reaction system under γ-ray irradiation,which means that the molecular chain structure of the radiation-synthesized PANI can be regulated by pH,nitrate concentration,and irradiation conditions.Radiation-synthesized PANI has a moderate protonation and oxidation state,which can be used for the preparation of PANI supercapacitors with better electrochemical properties than those prepared by chemical oxidation under the same conditions.This work presents a new radiation-synthesis method and polymerization mechanism of PANI,which not only expands the application of radiation technique in the field of polymer synthesis,but also provides a new idea for the structural regulation and electrochemical property optimization of PANI.展开更多
Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and ...Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and 500℃to obtain the delafossite AgFe0_(2)phase.The morphology and microstructure of the prepared AgFeO_(2)samples were characterized by using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),N_(2) adsorption/desorption,X-ray absorption spectroscopy(XAS),and Xray photoelectron spectroscopy(XPS)techniques.A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO_(2)nanoparticles in a 3 M KOH electrolyte.The delafossite AgFeO_(2)nanoparticles calcined at 100℃(AFO100)exhibited the highest surface area of 28.02 m^(2)·g^(-1)and outstanding electrochemical performance with specific capacitances of 229.71 F·g^(-1)at a current density of 1 A·g^(-1)and 358.32 F·g^(-1)at a scan rate of 2 mV·s^(-1).This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles,along with superior specific power and specific energy values of 797.46 W·kg^(-1)and 72.74Wh·kg^(-1),respectively.These findings indicate that delafossite AgFeO_(2)has great potential as an electrode material for supercapacitor applications.展开更多
The Fe_(1−x)Ni_(x)VO_(4)(x=0,0.05,0.10,and 0.20)nanoparticles in this work were successfully synthesized via a co-precipitation method.The structural,magnetic and electrochemical properties of the prepared Fe_(1−x)Ni_...The Fe_(1−x)Ni_(x)VO_(4)(x=0,0.05,0.10,and 0.20)nanoparticles in this work were successfully synthesized via a co-precipitation method.The structural,magnetic and electrochemical properties of the prepared Fe_(1−x)Ni_(x)VO_(4) nanoparticles were studied as a function of Ni content.The experimental results show that the prepared Ni-doped FeVO_(4) samples have a triclinic structure.Scanning electron microscopy(SEM)images reveal a decrease in average nanoparticle size with increasing Ni content,leading to an enhancement in both specific surface area and magnetization values.X-ray absorption near edge structure(XANES)analysis confirms the substitution of Ni^(2+)ions into Fe^(3+)sites.The magnetic investigation reveals that Ni-doped FeVO_(4) exhibits weak ferromagnetic behavior at room temperature,in contrast to the antiferromagnetic behavior observed in the undoped FeVO_(4).Electrochemical studies demonstrate that the Fe_(0.95)Ni_(0.05)VO_(4) electrode achieves the highest specific capacitance of 334.05 F·g^(−1) at a current density of 1 A·g^(−1),which is attributed to its smallest average pore diameter.In addition,the enhanced specific surface of the Fe_(0.8)Ni_(0.2)VO_(4) electrode is responsible for its outstanding cyclic stability.Overall,our results suggest that the magnetic and electrochemical properties of FeVO_(4) nanoparticles could be effectively tuned by varying Ni doping contents.展开更多
A unique sulfonated polyaniline/vanadate composite was synthesized and utilized as a composite anode in microbial fuel cells on ocean floor (BMFCs). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were em...A unique sulfonated polyaniline/vanadate composite was synthesized and utilized as a composite anode in microbial fuel cells on ocean floor (BMFCs). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were employed to characterize its chemical composition and morphology. Wettability of the composite anodes decreases due to the addition of polytetrafluoroethylene (PTFE). The electrochemical behavior of the composite anodes was investigated by means of linear sweep voltammetry and Tafel plot measurements. Compared with the plain graphite anode,the composite anode significantly improves the power density,5.5-fold higher,reaching 187.1 mW/m2 and gives a 27-fold higher exchange current density and a higher kinetic activity. A novel synergistic mechanism between sulfonated polyaniline and vanadate is proposed to explain the excellent electrochemical performance. This composite thus has great potential to be used as an anode material for a high-power BMFC.展开更多
Pristine LiNi0.5Mnl.5O4 and FePO4-coated one with Fd-3m space groups were prepared by a sol-gel method. The structure and performance were studied by X-ray diffraction （XRD） rietveld refinement, scanning electron mi...Pristine LiNi0.5Mnl.5O4 and FePO4-coated one with Fd-3m space groups were prepared by a sol-gel method. The structure and performance were studied by X-ray diffraction （XRD） rietveld refinement, scanning electron microscopy （SEM）, high resolution transmission electron microscopy （HRTEM）, energy dispersive spectrometer （EDS） mapping, electrochemical impedance spectroscopy （EIS） and charge- discharge tests, respectively. The lattice parameters of all samples almost remain the same from the Rietveld refinement, revealing that the crystallographic structure has no obvious difference between pris- tine LiNi0.5Mn1.5O4 and FePO4-coated one. All materials show similar morphologies with uniform particle distribution with small particle size, and FePO4 coating does not affect the morphology of LiNi0.5Mnl05O 4 material. EDS mapping and HRTEM show that FePO4 may be successfully wrapped around the surfaces of LiNio.sMnl.s04 particles, and provides an effective coating layer between the electrolyte and the surface of LiNi0.5Mn1.5O4 particles. FePO4 （1 wt%）-coated LiNio.sMnl.504 cathode shows the highest discharge capac- ity at high rate （2 C） among all samples. After 80 cycles, the reversible discharge capacity of FePO4 （1 wt%） coated LiNi0.5Mn0.5O4 is 117 mAh g^-1, but the pristine one only has 50 mAh g^-1. FeP04 coating is an effec- tive and controllable way to stabilize the LiNi0.5Mn1.5O4/electrolyte interface, and avoids the direct con- tact between LiNi0.5Mn1.5O4 powders and electrolyte, then suppresses the side reactions and enhances the electrochemical performance of the LiNi0.5Mn1.5O4.展开更多
Tin dioxide(SnO2) and La-doped(1%,5%,10% in mass ratio) SnO2 samples were prepared via a hydrothermal method. The as-prepared powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) ...Tin dioxide(SnO2) and La-doped(1%,5%,10% in mass ratio) SnO2 samples were prepared via a hydrothermal method. The as-prepared powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) . Results showed that the particle size of SnO2 decreased gradually with the increase of the doped La element. When used as anode materials of Li ion battery,the La-doped samples exhibited better cycling performance than the pure SnO2,and the cycling performance of the La-doped samples got better and better with the increase of the doped La. The better electrochemical performance of the doped material could be attributed to the doping of La element,which not only enabled SnO2 powders to have a good dispersivity but also reduced their particle size.展开更多
基金Project(2010CB630903)supported by the National Basic Research Program of ChinaProject(51374249)supported by the National Natural Science Foundation of China
文摘Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3＋ ions could accelerate the bioleaching,while the concentration of additional Fe^3＋ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3＋ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3＋ ions are added.
基金Project(2018YFC1900304)supported by the National Key R&D Program of ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,ChinaProject(2017SK2420)supported by the Science and Technology of Hunan Province,China。
文摘The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon testing, electrochemical measurement of open-circuit potential and linear sweep voltammetry. The results reveal that the existence of F-and Cl-ions in the simulated treated water accelerate the corrosion rate of Q235 A steel. The corrosion rate reaches maximum with F-concentration of 50 mg/L, Cl-concentration of 200 mg/L, respectively. However, Q235 A steel would passivate when an applied potential is added to the system. Meanwhile, the initiating passive potential becomes positive with F-, Cl-concentration increasing. There is a little influence of F-, Cl-concentration on the initiating passivation current density. Therefore, it is necessary to control F-, Cl-concentration in the treated water when it is recycled by the pipelines made of Q235 A steel.
基金Project(51202066)supported by the National Natural Science Foundation of ChinaProject supported by Scientific Research Fund of Hunan Provincial Science and Technology Department,China+1 种基金Project(2013-26)supported by the State Key Program of Jilin University,ChinaProject(2013001)supported by Key Laboratory of Ecological Impacts of Hydraulic-projects and Restoration of Aquatic Ecosystem,Minister of Water Resources,China
文摘Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric and differential-thermogravimetric analysis(TG-DTA) and energy dispersive X-ray spectrometry(EDS) techniques,showing uniform nanowire shape of LiFePO4/C with a diameter of 80-150 nm and a length of several microns.The heat-treated LiFePO4/C nanowires show excellent electrochemical properties of specific discharge capacity,rate capacity and cycling stability.In particular,the LiFePO4/C nanowires heat-treated at 400 °C show preferable first discharge specific capacity of 161 mA·h/g at 0.1C rate,while the voltage platform is 3.4 V and the first discharge specific capacity is 93 mA·h/g at 20C rate.The specific capacity retention is 98% after 50 cycles at 5C rate.
基金supported by the Natural Science Foundation of Hubei Province(2014CFB410)
文摘A novel copper（Ⅱ） complex derived from 1,4,7-triazacyclononane[CuL]_2（PF_6）_3×MeCN×H_2 O was synthesized and crystallographically characterized {L = 1,4-bis（2-carbamoylethyl）-7-benzimidazole-2-yl-methyl-1,4,7-triazacyclononane}. It crystallizes in triclinic, space group P1, with a = 13.2425（13）, b = 14.0807（15）, c = 17.6798（18）, α = 86.296（2）, β = 72.773（2）, γ= 68.905（2）o, V = 2934.5（5）A^3, Z = 2, D_c = 1.611 g/m^3, F（000） = 1456, M_r = 1423.09, m = 0.920 mm^-1. The final R = 0.0671 and wR = 0.1874 for 6501 observed reflections with I 〉 2σ（I）. The structural analysis shows that the complex cation（[CuL]_2^3＋） was formed by two complex cations, namely（[CuL^3]^2＋） and [CuL_（-H）~3]~＋） through a hydrogen bond. In each complex cation, the Cu（Ⅱ） lies in a distorted square pyramidal geometry. The redox behavior was studied by cyclic voltammetry（CV） in aqueous solution which indicates a reversible one electron redox reaction. The result of UV absorption, ethidium bromide（EB） fluorescence spectra indicated that the complex binds to CT-DNA in an intercalative mode. Superoxide dismutase（SOD） activity of the complex was determined by photoreduction of NBT, and the value of IC_（50） is 5.22 μmol·L^-1.
基金supported by the Chemistry College of Jilin Normal University
文摘A novel Schiff-base compound based on ferrocene C18H17OFeN3 （1） has been synthesized and characterized by X-ray diffraction. The title compound crystallizes in monoclinic, space group P21/c with a = 19.2343（17）, b = 10.5084（9）, c = 7.9373（7） A, β = 97.7740°, Z = 4, V = 1589.6（2） A^3, Dc = 1.451 g/cm^3, μ（MoKα） = 0.956 mm^-1, F（000） = 720, the final R = 0.0343 and wR = 0.0973 for 2759 observed reflections （I 〉 2σ（I））. Electrochemical measurements exhibit that compound 1 undergoes a reversible one-electron redox process.
基金National Natural Science Foundation of China(No. 20071014)
文摘A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electrochemical properties of the porphyrins were studied. The authors found that there was moderate electronic communication between the two porphyrin rings in the nanometer porphyrin dimer.
基金Supported by the National Natural Science Foundation of China （21061006） the Research of Natural Science and Technology Foundation of Guizhou Province （[2010]2006） the Graduate Scientific Innovation Project of Education Department of Guangxi Autonomous Region （1059330901009）
文摘Mesoporous aluminum-doped titanium dioxide(Al-TiO2) materials with high specific surface areas were prepared via a solid-state reaction route.The properties of these materials were characterized by X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),N2 absorption-desorption,ultraviolet visible light spectroscopy(UV-Vis) and electrochemical spectroscopy.The results show that the mesoporous structure of the product with ethanol is composed of anatase laced crystal walls with amorphous grain boundaries formed gradually by degradation.Compared with those without ethanol,these samples possess larger crystallite size since ethanol decreases the pore size at higher temperature.With the increase of ethanol amount,however,the crystallite size will grow.The amorphous grain boundaries in the mesoporous material,with a large impedance and low incidental cyclic potential,are difficult to effectively degrade and the phase transformation temperature is changed from 500 to 550℃.The growth rate of Al-TiO2 crystallites that obeys the quadratic polynomial equation may be controlled.
基金Supported by the National Natural Science Foundation of China (No 20371014 and 20671026)the Study Technological Innovation Projects Special Foundation of Harbin (2009RFXXG202)
文摘A supramolecular compound（H2en）2[Cu（en）2（H3O）2][Mo8O28]（en=ethylenediamine） was hydrothermally prepared and confirmed by elemental analysis and TG analysis.Single-crystal X-ray analysis reveals that the crystal crystallizes in the triclinic system,space group P1 with a=9.4635（4）,b=9.8645（5）,c=10.9794（5）A,α=69.2050（10）,β=72.3730（10）,γ=78.4510（10）o,Mr=1559.55,V=908.24（7）A^3,Z=1,Dc=2.851 g/m^3,F（000）=749,μ=3.350 mm^-1,S=1.000,the final R=0.0217 and wR=0.0567.The compound consists of（H2en）^2＋,[Mo8O28]^8-anion and [Cu（en）2（H3O）2]^2＋ cations and constructs a 3D supramolecular structure through hydrogen bonds between the nitrogen atoms from en of [Cu（en）2（H3O）2]^4＋ fragments and the terminal oxygen atoms from the [Mo8O28]^8-polyoxoanions.The electrochemical behavior of this compound has been studied in detail based on a solid bulk modified carbon paste electrode of compound（CPE）.
基金Project(21473258) supported by the National Natural Science Foundation of ChinaProject(13JJ1004) supported by Distinguished Young Scientists of Hunan Province,ChinaProject(NCET-11-0513) supported by Program for the New Century Excellent Talents in University,China
文摘In order to confirm the optimal Li content of Li-rich Mn-based cathode materials(a fixed mole ratio of Mn to Ni to Co is0.6:0.2:0.2),Li1+x(Mn0.6Ni0.2Co0.2)1-xO2(x=0,0.1,0.2,0.3)composites were obtained,which had a typical layered structure with R3m and C2/m space group observed from X-ray powder diffraction(XRD).Electron microscopy micrograph(SEM)reveals that the particle sizes in the range of0.4-1.1μm increase with an increase of x value.Li1.2(Mn0.6Ni0.2Co0.2)0.8O2sample delivers a larger initial discharge capacity of275.7mA·h/g at the current density of20mA/g in the potential range of2.0-4.8V,while Li1.1(Mn0.6Ni0.2Co0.2)0.9O2shows a better cycle performance with a capacity retention of93.8%at0.2C after50cycles,showing better reaction kinetics of lithium ion insertion and extraction.
基金supported by the National Natural Science Foundation of China (No. 21001054)the Jiangsu Higher Education Institutions (No.10KJB150003)+1 种基金Jiangsu Planned Projects for Postdoctoral Research Funds (1102126C)Foundation of UJS (No. 09JDG055) is gratefully acknowledged
文摘The title compound 5,10,15,20-tetrakis（4-chlorophenyl）porphyrin was synthesized and structurally characterized by X-ray single-crystal diffraction method. Crystal data： triclinic, space group P, Z=1, C50H32Cl4N4, Mr=830.60, a=6.4316（13）, b=11.322（2）, c=13.833（3） , α =91.44（3）, β=91.06（2）, γ=92.67（3）°, V=1005.7（3）3 , Dc=1.371 g/cm3 , μ（MoKα）=0.34 mm-1 , F（000）=428, R=0.0563 and wR=0.0867 for 2712 observed reflections with I 〉 2σ（I）. X-ray analysis reveals the phenyl rings and the pyrrole rings are not in the same plane. The dihedral angles between adjacent phenyl rings and pyrrole rings are 66.1 and 66.8°, respectively.
基金supported by the National Natural Science Foundation of China(No.21373178)the Natural Scientific Research Foundation of Shaanxi Provincial Education Office of China(No.13JS124)
文摘A new 3D Ag（I） coordination polymer, [Ag8（btc）2（bpp）2]n（1, H4btc = biphenyl- 2,2ˊ,4,4ˊ-tetracarboxylic acid, bpp = 1,2-bis（4-pyridyl）propane）, has been hydrothermally synthesi- zed and characterized by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. Complex 1 crystallizes in the triclinic system, space group P1 with a = 13.4899（8）, b = 13.4928（8）, c = 16.4575（10） , α = 102.7640（10）, β = 108.8100（10）, γ = 101.4940（10）°, V = 2644.1（3） 3, Z = 2, Dc = 2.401 Mg·m-3, μ = 2.978 mm-1, F（000） = 1840, the final R = 0.0481 and wR = 0.0955 for 6794 observed reflections with I 〉 2σ（I）. Complex 1 features a 3D framework formed by Ag（I）-carboxylate chains containing [Ag16（COO）16] secondary building block. Furthermore, thermal stability and electrochemical property of 1 are also investigated in detail.
基金the Construct Program of the Key Discipline in Hunan Provincethe Foundation of Education Committee of Hunan Province (06C195)
文摘One novel complex [Co（p-MBA）2（2,2＇-bipy）（H2O）]·（H2O） has been synthesized by the reaction of p-methylbenzoic acid with 2,2＇-bipyridine in the solvent mixture of water and methanol. It crystallizes in triclinic, space group P1 with a = 0.70479（14）, b = 1.1211（2）, c = 1.6718（3） nm, α = 103.806（3）, β = 90.795（3）, γ = 104.207（3）°, V= 1.2399（4） nm^3, Mr = 512.41, De= 1.373 g/cm^3, Z = 2, F（000） = 532,μ = 0.733 mm^-1, R = 0.0432 and ωR = 0.0957. The crystal structural analysis shows that the cobalt atom is coordinated with three oxygen atoms from two p-methylbenzoic acids and one water molecule and two nitrogen atoms from one 2,2＇-bipyridine, forming a distorted square-pyramidal coordination geometry. The cyclic voltammetry behavior of the complex is also reported.
文摘Cs0.35V2O5 was successfully synthesized as cathode material for lithium secondary battery by the rheological phase reaction method from Cs2CO3 and NH4VO3. The Cs0.35V2O5/Cu composite material was prepared by the displacement reaction in CuSO4 solution using zinc powder as a reductant. The structure and electrochemical property of the so-prepared powders were characterized by means of XRD （powder X-ray diffraction） and the galvanostatic discharge-charge techniques. The results show that the electrochemical property of Cs0.35V2O5/Cu composite material is significantly improved compared to the bulk Cs0.35V2O5 material. The Cs0.35V2O5/Cu composite material exhibits the first discharge capacity as high as 164.3 mAh.g -1 in the range of 4.2-1.8V at a current rate of 10 mA.g-1 and remains at a stable discharge capacity of about 110 mAh.g-1 within 40 cycles.
基金Project(2016YFB0300801)supported by the National Key Research and Development Program of ChinaProject(2012CB619502)supported by the National Basic Research Program of China
文摘Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombic efficiency.To address the issues,cesium nitrate(CsNO3)is selected as the additive to modify the electrolyte for lithium secondary battery.Here we report electrochemical performance of lithium secondary battery with different concentration of CsNO3 as electrolyte additive.The study result demonstrates that Coulombic efficiency of Li–Cu cells and the lifetime of symmetric lithium cells contained CsNO3 additive are improved greatly.Li–Cu cell with 0.05 mol/L CsNO3 and 0.15 mol/L LiNO3 as electrolyte additive presents the best electrochemical performance,having the highest Coulombic efficiency of around 97%and the lowest interfacial resistance.With increasing the concentration of CsNO3 as electrolyte additive,the electrochemical performance of cells becomes poor.Meanwhile,the morphology of lithium deposited films with CsNO3-modified electrolyte become smoother and more uniform compared with the basic electrolyte.
基金financially supported by the National Natural Science Foundation of China(Nos.51973205 and 51773189)the Fundamental Research Funds for the Central Universities(Nos.WK9110000066,WK345000005 and WK345000006).
文摘As a highly promising conductive polymer material,the synthesis method,structure regulation,and performance improvement of polyaniline(PANI)are hot research topics.In this work,the radiation-induced polymerization of aniline in HNO_(3)solution was successfully achieved at room temperature without the use of chemical oxidants.Through the analysis of the radiation chemical reactions of inorganic acids and nitrate salt solutions,the characterization of the intermediate free radicals in the irradiated systems,and the influence of the pH of the solutions on the polymerization activity and product morphologies,the radiation-induced polymerization mechanism of aniline is discussed in detail and proposed.Only at a condition of[HNO_(3)]>[aniline],i.e.,pH<2.5,PANI can be successfully obtained underγ-ray radiation.The polymerization begins with the oxidation of aniline cations to aniline cation radicals by·NO_(3)generated by radiolysis reactions,and undergoes repeated three steps of monomer free radical recombination,deprotonation,and oxidation reaction of·NO_(3),thus forming a PANI macromolecule.In addition to the polymerization reaction,the aniline units are protonated and oxidized because of the strongly acidity and oxidation of the reaction system under γ-ray irradiation,which means that the molecular chain structure of the radiation-synthesized PANI can be regulated by pH,nitrate concentration,and irradiation conditions.Radiation-synthesized PANI has a moderate protonation and oxidation state,which can be used for the preparation of PANI supercapacitors with better electrochemical properties than those prepared by chemical oxidation under the same conditions.This work presents a new radiation-synthesis method and polymerization mechanism of PANI,which not only expands the application of radiation technique in the field of polymer synthesis,but also provides a new idea for the structural regulation and electrochemical property optimization of PANI.
基金Suranaree University of Technology(SUT)Thailand Science,Research and Innovation(TSRI)National Science,Research and Innovation Fund(NSRF)(project cord.179314)。
文摘Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and 500℃to obtain the delafossite AgFe0_(2)phase.The morphology and microstructure of the prepared AgFeO_(2)samples were characterized by using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),N_(2) adsorption/desorption,X-ray absorption spectroscopy(XAS),and Xray photoelectron spectroscopy(XPS)techniques.A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO_(2)nanoparticles in a 3 M KOH electrolyte.The delafossite AgFeO_(2)nanoparticles calcined at 100℃(AFO100)exhibited the highest surface area of 28.02 m^(2)·g^(-1)and outstanding electrochemical performance with specific capacitances of 229.71 F·g^(-1)at a current density of 1 A·g^(-1)and 358.32 F·g^(-1)at a scan rate of 2 mV·s^(-1).This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles,along with superior specific power and specific energy values of 797.46 W·kg^(-1)and 72.74Wh·kg^(-1),respectively.These findings indicate that delafossite AgFeO_(2)has great potential as an electrode material for supercapacitor applications.
文摘The Fe_(1−x)Ni_(x)VO_(4)(x=0,0.05,0.10,and 0.20)nanoparticles in this work were successfully synthesized via a co-precipitation method.The structural,magnetic and electrochemical properties of the prepared Fe_(1−x)Ni_(x)VO_(4) nanoparticles were studied as a function of Ni content.The experimental results show that the prepared Ni-doped FeVO_(4) samples have a triclinic structure.Scanning electron microscopy(SEM)images reveal a decrease in average nanoparticle size with increasing Ni content,leading to an enhancement in both specific surface area and magnetization values.X-ray absorption near edge structure(XANES)analysis confirms the substitution of Ni^(2+)ions into Fe^(3+)sites.The magnetic investigation reveals that Ni-doped FeVO_(4) exhibits weak ferromagnetic behavior at room temperature,in contrast to the antiferromagnetic behavior observed in the undoped FeVO_(4).Electrochemical studies demonstrate that the Fe_(0.95)Ni_(0.05)VO_(4) electrode achieves the highest specific capacitance of 334.05 F·g^(−1) at a current density of 1 A·g^(−1),which is attributed to its smallest average pore diameter.In addition,the enhanced specific surface of the Fe_(0.8)Ni_(0.2)VO_(4) electrode is responsible for its outstanding cyclic stability.Overall,our results suggest that the magnetic and electrochemical properties of FeVO_(4) nanoparticles could be effectively tuned by varying Ni doping contents.
基金supported by the Scientific and Technological Development Plan Project of Shandong Province, China (2008GG10007003)the Key Laboratory of Marine Environment & Ecology, Ministry of Education (2008010)the Key Laboratory of Submarine Geoscience and Exploring Technology of Ministry of Education, Ocean University of China (2008-01)
文摘A unique sulfonated polyaniline/vanadate composite was synthesized and utilized as a composite anode in microbial fuel cells on ocean floor (BMFCs). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were employed to characterize its chemical composition and morphology. Wettability of the composite anodes decreases due to the addition of polytetrafluoroethylene (PTFE). The electrochemical behavior of the composite anodes was investigated by means of linear sweep voltammetry and Tafel plot measurements. Compared with the plain graphite anode,the composite anode significantly improves the power density,5.5-fold higher,reaching 187.1 mW/m2 and gives a 27-fold higher exchange current density and a higher kinetic activity. A novel synergistic mechanism between sulfonated polyaniline and vanadate is proposed to explain the excellent electrochemical performance. This composite thus has great potential to be used as an anode material for a high-power BMFC.
基金supported by the National Natural Science Foundation of China(51404002)Anhui Provincial Natural Science Foundation(1508085MB25)+1 种基金Natural Science Foundation of Guangdong Province(2016A030310127)Anhui Provincial Science Fund for Excellent Young Scholars(gxyqZD2016066)
文摘Pristine LiNi0.5Mnl.5O4 and FePO4-coated one with Fd-3m space groups were prepared by a sol-gel method. The structure and performance were studied by X-ray diffraction （XRD） rietveld refinement, scanning electron microscopy （SEM）, high resolution transmission electron microscopy （HRTEM）, energy dispersive spectrometer （EDS） mapping, electrochemical impedance spectroscopy （EIS） and charge- discharge tests, respectively. The lattice parameters of all samples almost remain the same from the Rietveld refinement, revealing that the crystallographic structure has no obvious difference between pris- tine LiNi0.5Mn1.5O4 and FePO4-coated one. All materials show similar morphologies with uniform particle distribution with small particle size, and FePO4 coating does not affect the morphology of LiNi0.5Mnl05O 4 material. EDS mapping and HRTEM show that FePO4 may be successfully wrapped around the surfaces of LiNio.sMnl.s04 particles, and provides an effective coating layer between the electrolyte and the surface of LiNi0.5Mn1.5O4 particles. FePO4 （1 wt%）-coated LiNio.sMnl.504 cathode shows the highest discharge capac- ity at high rate （2 C） among all samples. After 80 cycles, the reversible discharge capacity of FePO4 （1 wt%） coated LiNi0.5Mn0.5O4 is 117 mAh g^-1, but the pristine one only has 50 mAh g^-1. FeP04 coating is an effec- tive and controllable way to stabilize the LiNi0.5Mn1.5O4/electrolyte interface, and avoids the direct con- tact between LiNi0.5Mn1.5O4 powders and electrolyte, then suppresses the side reactions and enhances the electrochemical performance of the LiNi0.5Mn1.5O4.
基金Project supported by the National Natural Science Foundation of China (20871107)Henan Outstanding Youth Science Fund (0612002700)the Natural Science Foundation of the Education Department of Henan Province (2009A150031)
文摘Tin dioxide(SnO2) and La-doped(1%,5%,10% in mass ratio) SnO2 samples were prepared via a hydrothermal method. The as-prepared powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) . Results showed that the particle size of SnO2 decreased gradually with the increase of the doped La element. When used as anode materials of Li ion battery,the La-doped samples exhibited better cycling performance than the pure SnO2,and the cycling performance of the La-doped samples got better and better with the increase of the doped La. The better electrochemical performance of the doped material could be attributed to the doping of La element,which not only enabled SnO2 powders to have a good dispersivity but also reduced their particle size.
