The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this wo...The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.展开更多
We introduce our state-of-the art of“vacuum consistent electrochemistry”to an investigation of the interfaces between oxides and ionic liquid(IL).Pulsed laser deposition(PLD)has been one of the powerful and sophisti...We introduce our state-of-the art of“vacuum consistent electrochemistry”to an investigation of the interfaces between oxides and ionic liquid(IL).Pulsed laser deposition(PLD)has been one of the powerful and sophisticated techniques to realize nanoscale preparation of high-quality epitaxial oxide thin films.On the other hand,electrochemistry is a simple,very sensitive,and non-destructive analysis technique for solid-liquid interfaces.To ensure the reproducibility in experiment of the interfaces of such epitaxial oxide films,as well as bulk oxide single-crystals,with IL,we employ a home-built PLD-electrochemical(EC)system with IL as an electrolyte.The system allows one to perform all-in-vacuum experiments during the preparation of well-defined oxide electrode surfaces to their electrochemical analyses.The topics include electrochemical evaluations of the oxide’s own properties,such as carrier density and relative permittivity,and the interfacial properties of oxides in contact with IL,such as flat band potential and electric double layer(EDL)capacitance,ending with future perspectives in all-solid-state electrochemistry.展开更多
The development of highly active catalyst in pH-neutral media for oxygen evolution reaction(OER)is critical in the field of renewable energy storage and conversion.Nevertheless,the slow kinetics of proton-coupled elec...The development of highly active catalyst in pH-neutral media for oxygen evolution reaction(OER)is critical in the field of renewable energy storage and conversion.Nevertheless,the slow kinetics of proton-coupled electron transfer(PCET)hinders the overall OER efficiency.Herein,we report an ionic liquid(IL)modified CoSn(OH)_(6)nanocubes(denoted as CoS-n(OH)_(6)-IL),which could be prepared through a facile strategy.The modified IL would not change the structural character-istics of CoSn(OH)_(6),but could effectively regulate the local proton activity near the active sites.The CoSn(OH)_(6)-IL exhibited higher intrinsic OER performances than the pristine CoSn(OH)_(6)in neutral media.For example,the current density of CoS-n(OH)_(6)-IL at 1.8 V versus reversible hydrogen electrode(RHE)was about 4 times higher than that of CoSn(OH)_(6).According to the pH-dependent kinetic investigations,operando electrochemical impedance spectroscopic,chemical probe tests,and deuterium kinetic isotope effects,the interfacial layer of IL could be utilized as a proton transfer mediator to promote the proton transfer,which enhances the surface coverage of OER intermediates and reduces the activation barrier.Consequent-ly,the sluggish OER kinetics would be efficiently accelerated.This study provides a facile and effective strategy to facilitate the PCET processes and is beneficial to guide the rational design of OER electrocatalysts.展开更多
Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This charact...Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This characteristic holds significant implications in the realm of novel satellite propulsion.Introducing a fraction of the electrical energy into energetic ionic liquid fuels,the thermal decomposition process is facilitated by reducing the apparent activation energy required,and electrical energy can trigger the electrochemical decomposition of ionic liquids,presenting a promising approach to enhance combustion efficiency and energy release.This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate([EMIm]NO_(3)),revealing the effective alteration of the activation energy of[EMIm]NO_(3).The pyrolysis,electrochemical decomposition,and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry(TG-DSC-FTIR-MS)and gas chromatography(GC)analyses,elucidating the degradation mechanism of[EMIm]NO_(3).Furthermore,an external voltage was introduced during the combustion of[EMIm]NO_(3),demonstrating the impact of voltage on the combustion process.展开更多
The electrochemical behavior of Al(Ⅲ)in urea-1-butyl-3-methylimidazolium chloride-aluminum chloride(urea-BMIC-AlCl_(3))ionic liquids,and the effect of potential and temperature on the characterization of cathode prod...The electrochemical behavior of Al(Ⅲ)in urea-1-butyl-3-methylimidazolium chloride-aluminum chloride(urea-BMIC-AlCl_(3))ionic liquids,and the effect of potential and temperature on the characterization of cathode products,current efficiency and energy consumption of aluminum electrorefining have been investigated.Cyclic voltammetry showed that the electrochemical reduction of Al(Ⅲ)was a one-step three-electron-transfer irreversible reaction,and the electrochemical reaction was controlled by diffusion.The diffusion coefficient of Al(Ⅲ)in urea-BMIC-AlCl_(3)ionic liquids at 313 K was 1.94×10^(−7)cm^(2)/s.The 7075 aluminum alloy was used as an anode for electrorefining,and the cathode products were analyzed by XRD,SEM and EDS.The results from XRD analysis indicated that the main phase of the cathode products was aluminum.The results from SEM and EDS characterization revealed that the cathode product obtained by electrorefining−1.2 V(vs.Al)was dense and uniform,and the mass fraction of aluminum decreased from 99.61%to 99.10%as the experimental temperature increased from 313 K to 333 K.In this work,the optimum experimental conditions were−1.2 V(vs.Al)and 313 K.At this time,the cathode current efficiency was 97.80%,while the energy consumption was 3.72 kW·h/kg.展开更多
In the pursuit of advancing imidazolium-based energetic ionic liquids (EILs),the current study is devoted to the synthesis and characterization of 1,3-dibutyl-imidazolium azide ([BBIm][N_(3)]),as a novel member in thi...In the pursuit of advancing imidazolium-based energetic ionic liquids (EILs),the current study is devoted to the synthesis and characterization of 1,3-dibutyl-imidazolium azide ([BBIm][N_(3)]),as a novel member in this ionic liquids class.The chemical structure of this EIL was rigorously characterized and confirmed using FTIR spectroscopy,1D,and 2D-NMR analyses.The thermal behavior assessment was conducted through DSC and TGA experiments.DSC analysis revealed an endothermic glass transition at T_(g)=-61℃,followed by an exothermic degradation event at T_(onset)=311℃.Similarly,TGA thermograms exhibited a one-stage decomposition process resulting in 100% mass loss of the sample.Furthermore,the short-term thermal stability of the azide EIL was investigated by combining the non-isothermal TGA data with the TAS,it-KAS,and VYA/CE isoconversional kinetic approaches.Consequently,the Arrhenius parameters(E_(a)=154 kJ·mol^(-1),Log(A/s^(-1))=11.8) and the most probable reaction model g(a) were determined.The observed high decomposition temperatures and the significantly elevated activation energy affirm the enhanced thermal stability of the modified EIL.These findings revealed that[BBIm][N_(3)]EIL can be a promising candidate for advanced energetic material application.展开更多
Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve fle...Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.展开更多
CeO2 nanorods were synthesized by a hydrothermal method at 160℃ from CeC16-6H20 and NH3.H20 in the presence of an ionic liquid 1-butyl-3-methyl-imidazolium chloride （[Bmim]C1）. The phase and morphology of the resul...CeO2 nanorods were synthesized by a hydrothermal method at 160℃ from CeC16-6H20 and NH3.H20 in the presence of an ionic liquid 1-butyl-3-methyl-imidazolium chloride （[Bmim]C1）. The phase and morphology of the result- ing products were characterized by X-ray diffraction （XRD） and high-resolution transmission electron microscopy （HRTEM）, respectively. The results reveal that morphology of CeO2 prepared in the presence of the ionic liquid is nano- rod while it changes to irregular nanoparticle without ionic liquid. The resulting nanorods are about 13-25 nm in diameter and 200-500 nm in length. With the increase of ionic concentration, nanorods were disappeared gradually and nanoparticles were obtained. Moreover, increasing the hydrothermal temperature to 180℃, nanospheres at size of 19-24 nm could be synthesized by aggregation of-2 nm nanocrystals.展开更多
The effect of two alkylpyridinium ionic liquids （py-iLs） including N-butylpyridinium hydrogen sulfate （BpyHSO4） and N-hexylpyridinium hydrogen sulfate （HpyHSO4） on the kinetics of copper electrodeposition from a...The effect of two alkylpyridinium ionic liquids （py-iLs） including N-butylpyridinium hydrogen sulfate （BpyHSO4） and N-hexylpyridinium hydrogen sulfate （HpyHSO4） on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on CuE＋ electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope （SEM） and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of （111）, （200） and （311） planes.展开更多
Fuel desulfurization is an appealing topic for the chemical industry since severe environmental regulations regarding SO_2 emissions have been legislated in many countries. In order to reduce the amount of sulfur-cont...Fuel desulfurization is an appealing topic for the chemical industry since severe environmental regulations regarding SO_2 emissions have been legislated in many countries. In order to reduce the amount of sulfur-containing compounds in fuels,responsible for high SO_x emission levels,a green chemistry approach is compulsory. In this paper,vanadium salen and salophen complexes were used in the oxidation of a model aromatic sulfide,such as dibenzothiophene( DBT),in the presence of H_2O_2 as green oxidant. The oxidative process was successfully coupled with the extraction of the oxidized compounds by ionic liquids. The system resulted highly selective for sulfide oxidation,showing poor reactivity toward the oxidation of alkenes and allowing a significant reduction of S content in a model benzine. To note,the use of microwave in place of standard heating allowed to obtain 98% of DBT oxidation and almost complete sulfur extraction in the model fuel in 1000 s. For these reasons,this system was considered an easy,rapid and clean process to achieve fuel desulfurization.展开更多
Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Sever...Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.展开更多
In order to further improve the driving performance of ionic polymer metal composites(IPMCs),Nafion/graphene quantum dots(GQDs)hybrid membranes incorporating GQDs with various contents of 0,0.1 wt.%,0.5 wt.%,1.0 wt.%,...In order to further improve the driving performance of ionic polymer metal composites(IPMCs),Nafion/graphene quantum dots(GQDs)hybrid membranes incorporating GQDs with various contents of 0,0.1 wt.%,0.5 wt.%,1.0 wt.%,2.0 wt.%and 4.0 wt.%were fabricated by solution casting,and then IPMCs were manufactured by electroless plating.The water contents and elastic moduli of the hybrid membranes were tested.The morphology characteristics of the hybrid membranes and the IPMCs were observed,and the current,AC impedance,blocking force and displacement of the IPMCs were measured.The results show that the elastic modulus of the hybrid membranes decreases,the water content increases,and the actuation performance of the IPMCs improves significantly after the addition of GQDs.IPMC with 1.0 wt.%GQDs exhibits the best driving property.Compared with the IPMC without GQDs,the working current,ion conductivity,blocking force,and tip displacement increase by 94.67%,311.11%,53.66%,and 66.07%,respectively.These results lay a solid foundation for the preparation of IPMCs with high performance,and further broaden their applications in biomedical devices and bionic robots.展开更多
As a new ionic polymer-metal composite(IPMC) for artificial muscle,the mechanical performance parameters and the relationship between the deformation and the electrical parameters of the IPMC were studied. With the di...As a new ionic polymer-metal composite(IPMC) for artificial muscle,the mechanical performance parameters and the relationship between the deformation and the electrical parameters of the IPMC were studied. With the digital speckle correlation method,the constitutive relationship of the IPMC was confirmed. With non-contact photography measurement,a cantilever setup was designed to confirm the relationship between the deformation of the IPMC film and the applied voltage. The relationship curve of tip displacement of the IPMC cantilever setup vs the voltage was achieved. The results indicate that the IPMC is isotropic,its elastic modulus is 232 MPa and Poisson ratio is 0.163. The curve achieved from the test of the tip displacement of the IPMC cantilever setup shows that the tip displacement reaches the maximum when the stimulated voltage is 5 V. And the tip displacement descends largely when the frequency of the applied voltage is between 30 mHz and 100 mHz.展开更多
The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a st...The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a strain-control experiment under different irradiation doses' samples(0,10,20,50,100 kGy) at different shear rates and temperatures.The curves of shear stress against shear rate present that the viscosity of ionic liquid is insensitive to shear rate;the viscosity of ionic liquids decreases with increasing temperature,and can be fitted by Arrhenius equation very well.Gamma radiation causes a decrease of viscosity of [Me3NC2H4OH]+[Zn3Cl7]-by greater than 10%,but it does not impair the viscosity of [Me3NC2H4OH]+[Zn2Cl5]-(within the experimental error) except 20 kGy irradiated sample.The results show that the radiation stability of [Me3NC2H4OH]+[Zn2Cl5]-is higher than that of [Me3NC2H4OH]+[Zn3Cl7]-.展开更多
Some expressions were proposed in the previous report to exp-ress the relation between the entropies S°<sub>298</sub> and the bond parameterZ/r in the same type of compounds.Based on this we derived a...Some expressions were proposed in the previous report to exp-ress the relation between the entropies S°<sub>298</sub> and the bond parameterZ/r in the same type of compounds.Based on this we derived a rela-tion formula for calculating the ionic entropies and established a展开更多
A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the ...A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the catalytic performance of the solid bases was evaluated. Both the reaction temperature and time can affect the yield of lactic acid. A high yield （97%） of lactic acid was achieved under the optimal reaction condition. The IH NMR spectra and HPLC-MS were used to identify the formation of the lactic acid and variations of ionic liquid. It is found that ionic-liquids have a unique solvent effect for glucose and bases. Water can be used as solvent to extract calcium lactate. This shows a great potential of hydrophobic ionic liquids in the solid bases catalyzed reaction that is limited by the weak solubility of solid bases in organic and water solution.展开更多
The electrochemical behavior of CoCl2 in 1-butyl-3-methylimidazolium hexafluorophosphate (bmim]PF6) was investigated by cyclic voltammetry. The cyclic voltammograms were obtained from electrochemical measurement under...The electrochemical behavior of CoCl2 in 1-butyl-3-methylimidazolium hexafluorophosphate (bmim]PF6) was investigated by cyclic voltammetry. The cyclic voltammograms were obtained from electrochemical measurement under different temperatures, and the reversible behavior for Co2+/Co3+ redox couple on glassy carbon electrode in bmim]PF6 was confirmed by the characteristic of the peak currents. The diffusion coefficients (about 10-11 m2/s) of Co2+ in bmim]PF6 under different temperatures were evaluated from the dependence of the peak current density on the potential scan rates in cyclic voltammograms. It is found that the diffusion coefficient increases with increasing temperature. Diffusion activation energy of Co2+ in bmim]PF6 is also calculated to be 23.4 kJ/mol according to the relationship between diffusion coefficient and temperature.展开更多
Although lots of basic studies , such as the hydrolysis and dissolution of lignocelluloses has made great progress in recent years , the hydrolysates containing complex mixture of pentose and hexose are very hard to b...Although lots of basic studies , such as the hydrolysis and dissolution of lignocelluloses has made great progress in recent years , the hydrolysates containing complex mixture of pentose and hexose are very hard to be separated , and these process sometimes cause serious environmental problems in practical application of cellulose polymer degradation science.Herein , an efficient two-stage method for selective hydrolysis of lignocelluloses biomass is being developed in this paper by controlling of pH in an ionic liquid.The lignin-hemicelluloses matrix in corn stalk was hydrolyzed into xylose in 23.1% yield in the first stage ; and cellulose-rich residues from the first stage was by farther hydrolyzed to provide a glucose in 26.9%yield.Structure of the products were identified by 13 C NMR.It should be mentioned that , the ionic liquid which can be regenerated and reused throughout the process. The present work significantly opens an a new path to utilize each component of lignocellulose as raw materials producing biofuels , renewable energy and fine chemicals.展开更多
文摘The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.
文摘We introduce our state-of-the art of“vacuum consistent electrochemistry”to an investigation of the interfaces between oxides and ionic liquid(IL).Pulsed laser deposition(PLD)has been one of the powerful and sophisticated techniques to realize nanoscale preparation of high-quality epitaxial oxide thin films.On the other hand,electrochemistry is a simple,very sensitive,and non-destructive analysis technique for solid-liquid interfaces.To ensure the reproducibility in experiment of the interfaces of such epitaxial oxide films,as well as bulk oxide single-crystals,with IL,we employ a home-built PLD-electrochemical(EC)system with IL as an electrolyte.The system allows one to perform all-in-vacuum experiments during the preparation of well-defined oxide electrode surfaces to their electrochemical analyses.The topics include electrochemical evaluations of the oxide’s own properties,such as carrier density and relative permittivity,and the interfacial properties of oxides in contact with IL,such as flat band potential and electric double layer(EDL)capacitance,ending with future perspectives in all-solid-state electrochemistry.
基金supported by the National Natural Science Foundation of China(22209040,22202063).
文摘The development of highly active catalyst in pH-neutral media for oxygen evolution reaction(OER)is critical in the field of renewable energy storage and conversion.Nevertheless,the slow kinetics of proton-coupled electron transfer(PCET)hinders the overall OER efficiency.Herein,we report an ionic liquid(IL)modified CoSn(OH)_(6)nanocubes(denoted as CoS-n(OH)_(6)-IL),which could be prepared through a facile strategy.The modified IL would not change the structural character-istics of CoSn(OH)_(6),but could effectively regulate the local proton activity near the active sites.The CoSn(OH)_(6)-IL exhibited higher intrinsic OER performances than the pristine CoSn(OH)_(6)in neutral media.For example,the current density of CoS-n(OH)_(6)-IL at 1.8 V versus reversible hydrogen electrode(RHE)was about 4 times higher than that of CoSn(OH)_(6).According to the pH-dependent kinetic investigations,operando electrochemical impedance spectroscopic,chemical probe tests,and deuterium kinetic isotope effects,the interfacial layer of IL could be utilized as a proton transfer mediator to promote the proton transfer,which enhances the surface coverage of OER intermediates and reduces the activation barrier.Consequent-ly,the sluggish OER kinetics would be efficiently accelerated.This study provides a facile and effective strategy to facilitate the PCET processes and is beneficial to guide the rational design of OER electrocatalysts.
基金supported by the National Natural Science Foundation of China(Grant No.52206165)。
文摘Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This characteristic holds significant implications in the realm of novel satellite propulsion.Introducing a fraction of the electrical energy into energetic ionic liquid fuels,the thermal decomposition process is facilitated by reducing the apparent activation energy required,and electrical energy can trigger the electrochemical decomposition of ionic liquids,presenting a promising approach to enhance combustion efficiency and energy release.This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate([EMIm]NO_(3)),revealing the effective alteration of the activation energy of[EMIm]NO_(3).The pyrolysis,electrochemical decomposition,and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry(TG-DSC-FTIR-MS)and gas chromatography(GC)analyses,elucidating the degradation mechanism of[EMIm]NO_(3).Furthermore,an external voltage was introduced during the combustion of[EMIm]NO_(3),demonstrating the impact of voltage on the combustion process.
基金Project(52004062)supported by the National Natural Science Foundation of ChinaProject(2020-MS-084)supported by the Natural Science Foundation of Liaoning Province,ChinaProject(N2125014)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The electrochemical behavior of Al(Ⅲ)in urea-1-butyl-3-methylimidazolium chloride-aluminum chloride(urea-BMIC-AlCl_(3))ionic liquids,and the effect of potential and temperature on the characterization of cathode products,current efficiency and energy consumption of aluminum electrorefining have been investigated.Cyclic voltammetry showed that the electrochemical reduction of Al(Ⅲ)was a one-step three-electron-transfer irreversible reaction,and the electrochemical reaction was controlled by diffusion.The diffusion coefficient of Al(Ⅲ)in urea-BMIC-AlCl_(3)ionic liquids at 313 K was 1.94×10^(−7)cm^(2)/s.The 7075 aluminum alloy was used as an anode for electrorefining,and the cathode products were analyzed by XRD,SEM and EDS.The results from XRD analysis indicated that the main phase of the cathode products was aluminum.The results from SEM and EDS characterization revealed that the cathode product obtained by electrorefining−1.2 V(vs.Al)was dense and uniform,and the mass fraction of aluminum decreased from 99.61%to 99.10%as the experimental temperature increased from 313 K to 333 K.In this work,the optimum experimental conditions were−1.2 V(vs.Al)and 313 K.At this time,the cathode current efficiency was 97.80%,while the energy consumption was 3.72 kW·h/kg.
文摘In the pursuit of advancing imidazolium-based energetic ionic liquids (EILs),the current study is devoted to the synthesis and characterization of 1,3-dibutyl-imidazolium azide ([BBIm][N_(3)]),as a novel member in this ionic liquids class.The chemical structure of this EIL was rigorously characterized and confirmed using FTIR spectroscopy,1D,and 2D-NMR analyses.The thermal behavior assessment was conducted through DSC and TGA experiments.DSC analysis revealed an endothermic glass transition at T_(g)=-61℃,followed by an exothermic degradation event at T_(onset)=311℃.Similarly,TGA thermograms exhibited a one-stage decomposition process resulting in 100% mass loss of the sample.Furthermore,the short-term thermal stability of the azide EIL was investigated by combining the non-isothermal TGA data with the TAS,it-KAS,and VYA/CE isoconversional kinetic approaches.Consequently,the Arrhenius parameters(E_(a)=154 kJ·mol^(-1),Log(A/s^(-1))=11.8) and the most probable reaction model g(a) were determined.The observed high decomposition temperatures and the significantly elevated activation energy affirm the enhanced thermal stability of the modified EIL.These findings revealed that[BBIm][N_(3)]EIL can be a promising candidate for advanced energetic material application.
基金Project(51275102)supported by the National Natural Science Foundation of ChinaProject(HEUCF140713)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.
文摘CeO2 nanorods were synthesized by a hydrothermal method at 160℃ from CeC16-6H20 and NH3.H20 in the presence of an ionic liquid 1-butyl-3-methyl-imidazolium chloride （[Bmim]C1）. The phase and morphology of the result- ing products were characterized by X-ray diffraction （XRD） and high-resolution transmission electron microscopy （HRTEM）, respectively. The results reveal that morphology of CeO2 prepared in the presence of the ionic liquid is nano- rod while it changes to irregular nanoparticle without ionic liquid. The resulting nanorods are about 13-25 nm in diameter and 200-500 nm in length. With the increase of ionic concentration, nanorods were disappeared gradually and nanoparticles were obtained. Moreover, increasing the hydrothermal temperature to 180℃, nanospheres at size of 19-24 nm could be synthesized by aggregation of-2 nm nanocrystals.
基金Projects(51204080, 51274108) supported by the National Natural Science Foundation of ChinaProject(2011FA009) supported by the Natural Science Foundation of Yunnan Province, ChinaProject(2011FZ020) supported by the Application Research Foundation of Yunnan Province, China
文摘The effect of two alkylpyridinium ionic liquids （py-iLs） including N-butylpyridinium hydrogen sulfate （BpyHSO4） and N-hexylpyridinium hydrogen sulfate （HpyHSO4） on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on CuE＋ electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope （SEM） and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of （111）, （200） and （311） planes.
基金The project was supported by the University of Rome“Tor Vergata”,SUSCARE project.
文摘Fuel desulfurization is an appealing topic for the chemical industry since severe environmental regulations regarding SO_2 emissions have been legislated in many countries. In order to reduce the amount of sulfur-containing compounds in fuels,responsible for high SO_x emission levels,a green chemistry approach is compulsory. In this paper,vanadium salen and salophen complexes were used in the oxidation of a model aromatic sulfide,such as dibenzothiophene( DBT),in the presence of H_2O_2 as green oxidant. The oxidative process was successfully coupled with the extraction of the oxidized compounds by ionic liquids. The system resulted highly selective for sulfide oxidation,showing poor reactivity toward the oxidation of alkenes and allowing a significant reduction of S content in a model benzine. To note,the use of microwave in place of standard heating allowed to obtain 98% of DBT oxidation and almost complete sulfur extraction in the model fuel in 1000 s. For these reasons,this system was considered an easy,rapid and clean process to achieve fuel desulfurization.
基金Project(21176262) supported by the National Natural Science Foundation of ChinaProject(2010WK3029) supported by Science and Technology Program of Hunan Province,China
文摘Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.
基金Projects(51605220,U1637101)supported by the National Natural Science Foundation of ChinaProject(BK20160793)supported by the Jiangsu Provincial Natural Science Foundation,ChinaProject(NS2020029)supported by the Fundamental Research Funds for the Central Universities,China。
文摘In order to further improve the driving performance of ionic polymer metal composites(IPMCs),Nafion/graphene quantum dots(GQDs)hybrid membranes incorporating GQDs with various contents of 0,0.1 wt.%,0.5 wt.%,1.0 wt.%,2.0 wt.%and 4.0 wt.%were fabricated by solution casting,and then IPMCs were manufactured by electroless plating.The water contents and elastic moduli of the hybrid membranes were tested.The morphology characteristics of the hybrid membranes and the IPMCs were observed,and the current,AC impedance,blocking force and displacement of the IPMCs were measured.The results show that the elastic modulus of the hybrid membranes decreases,the water content increases,and the actuation performance of the IPMCs improves significantly after the addition of GQDs.IPMC with 1.0 wt.%GQDs exhibits the best driving property.Compared with the IPMC without GQDs,the working current,ion conductivity,blocking force,and tip displacement increase by 94.67%,311.11%,53.66%,and 66.07%,respectively.These results lay a solid foundation for the preparation of IPMCs with high performance,and further broaden their applications in biomedical devices and bionic robots.
基金Project(50575228) supported by the National Natural Science Foundation of ChinaProject(07JJ3089) supported by the Hunan Provincial Natural Science Foundation of China
文摘As a new ionic polymer-metal composite(IPMC) for artificial muscle,the mechanical performance parameters and the relationship between the deformation and the electrical parameters of the IPMC were studied. With the digital speckle correlation method,the constitutive relationship of the IPMC was confirmed. With non-contact photography measurement,a cantilever setup was designed to confirm the relationship between the deformation of the IPMC film and the applied voltage. The relationship curve of tip displacement of the IPMC cantilever setup vs the voltage was achieved. The results indicate that the IPMC is isotropic,its elastic modulus is 232 MPa and Poisson ratio is 0.163. The curve achieved from the test of the tip displacement of the IPMC cantilever setup shows that the tip displacement reaches the maximum when the stimulated voltage is 5 V. And the tip displacement descends largely when the frequency of the applied voltage is between 30 mHz and 100 mHz.
基金Project(26120231) supported by the "Hundred Talents" project of the Chinese Academy of Science
文摘The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a strain-control experiment under different irradiation doses' samples(0,10,20,50,100 kGy) at different shear rates and temperatures.The curves of shear stress against shear rate present that the viscosity of ionic liquid is insensitive to shear rate;the viscosity of ionic liquids decreases with increasing temperature,and can be fitted by Arrhenius equation very well.Gamma radiation causes a decrease of viscosity of [Me3NC2H4OH]+[Zn3Cl7]-by greater than 10%,but it does not impair the viscosity of [Me3NC2H4OH]+[Zn2Cl5]-(within the experimental error) except 20 kGy irradiated sample.The results show that the radiation stability of [Me3NC2H4OH]+[Zn2Cl5]-is higher than that of [Me3NC2H4OH]+[Zn3Cl7]-.
文摘Some expressions were proposed in the previous report to exp-ress the relation between the entropies S°<sub>298</sub> and the bond parameterZ/r in the same type of compounds.Based on this we derived a rela-tion formula for calculating the ionic entropies and established a
基金Project(2006BAE02B05) supported by the Key Projects in the National Science and Technology Pillar Program During the 11th Five-year Plan PeriodProject(2005CB221406) supported by the National Basic Research Program of China
文摘A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the catalytic performance of the solid bases was evaluated. Both the reaction temperature and time can affect the yield of lactic acid. A high yield （97%） of lactic acid was achieved under the optimal reaction condition. The IH NMR spectra and HPLC-MS were used to identify the formation of the lactic acid and variations of ionic liquid. It is found that ionic-liquids have a unique solvent effect for glucose and bases. Water can be used as solvent to extract calcium lactate. This shows a great potential of hydrophobic ionic liquids in the solid bases catalyzed reaction that is limited by the weak solubility of solid bases in organic and water solution.
基金Project(2005-383) supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education, China
文摘The electrochemical behavior of CoCl2 in 1-butyl-3-methylimidazolium hexafluorophosphate (bmim]PF6) was investigated by cyclic voltammetry. The cyclic voltammograms were obtained from electrochemical measurement under different temperatures, and the reversible behavior for Co2+/Co3+ redox couple on glassy carbon electrode in bmim]PF6 was confirmed by the characteristic of the peak currents. The diffusion coefficients (about 10-11 m2/s) of Co2+ in bmim]PF6 under different temperatures were evaluated from the dependence of the peak current density on the potential scan rates in cyclic voltammograms. It is found that the diffusion coefficient increases with increasing temperature. Diffusion activation energy of Co2+ in bmim]PF6 is also calculated to be 23.4 kJ/mol according to the relationship between diffusion coefficient and temperature.
文摘Although lots of basic studies , such as the hydrolysis and dissolution of lignocelluloses has made great progress in recent years , the hydrolysates containing complex mixture of pentose and hexose are very hard to be separated , and these process sometimes cause serious environmental problems in practical application of cellulose polymer degradation science.Herein , an efficient two-stage method for selective hydrolysis of lignocelluloses biomass is being developed in this paper by controlling of pH in an ionic liquid.The lignin-hemicelluloses matrix in corn stalk was hydrolyzed into xylose in 23.1% yield in the first stage ; and cellulose-rich residues from the first stage was by farther hydrolyzed to provide a glucose in 26.9%yield.Structure of the products were identified by 13 C NMR.It should be mentioned that , the ionic liquid which can be regenerated and reused throughout the process. The present work significantly opens an a new path to utilize each component of lignocellulose as raw materials producing biofuels , renewable energy and fine chemicals.
