Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high ...Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity,sluggish ion kinetics,and severe volume expansion during the insertion/extraction process of Zn^(2+).Herein,a series of V_(2)O_(3)nanospheres embedded N-doped carbon nanofiber structures with various V_(2)O_(3)spherical morphologies(solid,core-shell,hollow)have been designed for the first time by an electrospinning technique followed thermal treatments.The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability,but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V_(2)O_(3)particles.Furthermore,the varied morphological structures of V_(2)O_(3)with abundant oxygen vacancies can alleviate the volume change and increase the Zn^(2+)pathway.Besides,the phase transition between V_(2)O_(3)and Zn_XV_(2)O_(5-m)·n H_(2)O in the cycling was also certified.As a result,the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells,which is also confirmed through density functional theory(DFT)calculations.Even assembled into flexible ZIBs,the sample still exhibits superior electrochemical performance,which may afford new design concept for flexible cathode materials of ZIBs.展开更多
Partition coefficients of Urokinase(UK)were measured in aqueous two-phase systems con-taining polyethylene glycol and potassium phosphate at 273.2K.Based on the Diamond-Hsu model,a modified expression was obtained for...Partition coefficients of Urokinase(UK)were measured in aqueous two-phase systems con-taining polyethylene glycol and potassium phosphate at 273.2K.Based on the Diamond-Hsu model,a modified expression was obtained for the correlation of enzyme partitioning in theabove-mentioned systems.Utilizing a modified form,the partitioning data of UK and heteroproteinwere correlated.The results show that the modified model is simple gives good precision.and will fa-cilitate engineering scale-up of aqueous two-phase systems for certain proteins purification.展开更多
Salt lake brine is a complex salt-water system under natural environment.Although many models can express the thermodynamic properties and phase equilibrium of electrolyte aqueous solution,the multi-temperature charac...Salt lake brine is a complex salt-water system under natural environment.Although many models can express the thermodynamic properties and phase equilibrium of electrolyte aqueous solution,the multi-temperature characteristics and predictability are still the goals of model development.In this study,a comprehensive thermodynamic model system is re-established based on the eNRTL model and some improvements:(1) new expression of long-range electrostatic term with symmetrical reference state is proposed to handle the electrolyte solution covering entire concentration range;(2) the temperature dependence of the binary interaction parameters is formulated with a Gibbs Helmholtz expression containing three temperature coefficients,the liquid parameters,which associated with Gibbs energy,enthalpy,and heat capacity contribution;and(3) liquid parameters and solid species data are regressed from properties and solubility data at full temperature range.Together the activity coefficient model,property models and parameters of liquid and solid offer a comprehensive thermodynamic model system for the typical bittern of MgCl2-CaCl2-H2 O binary and ternary systems,and it shows excellent agreement with the literature data for the ternary and binary systems.The successful prediction of complete phase diagram of ternary system shows that the model has the ability to deal with high concentration and high non-idealitv system,and the ability to extrapolate the temperature.展开更多
It is still a challenging task to accurately and temperature-continuously express the thermodynamic properties and phase equilibrium behaviors of the salt-lake brine with multi-component,multitemperature and high conc...It is still a challenging task to accurately and temperature-continuously express the thermodynamic properties and phase equilibrium behaviors of the salt-lake brine with multi-component,multitemperature and high concentration.The essential subsystem of sulfate type brine,aqueous Li^(+)-Na^(+)-K^(+)-SO_(4)^(2-) and its subsystems across a temperature range from 250 K to 643 K are investigated with the improved comprehensive thermodynamic model.Liquid parameters(Δg_(IJ),Δh_(IJ),and ΔC_(p,IJ))associated with the contributions of Gibbs energy,enthalpy,and heat capacity to the binary interaction parameters,i.e.the temperature coefficients of eNRTL parameters formulated with a Gibbs Helmholtz expression,are determined via multi-objective optimization method.The solid constantsΔ_(f)G_(k)°^((298.15))andΔ_(f)H_(k)°^((298.15))of11 solid species occurred in the quaternary system are rebuilt from multi-temperature solubilities.The modeling results show the accurate representation of(1)solution properties and binary phase diagram at temperature ranges from eutectic points to 643 K;(2)isothermal phase diagrams for Li_(2)SO_(4)-Na_(2)SO_(4)-H_(2)O,Li_(2)SO_(4)-K_(2)SO_(4)-H_(2)O and Na_(2)SO_(4)-K_(2)SO_(4)-H_(2)O ternary systems.The predicted results of complete structure and polythermal phase diagram of ternary systems and the isothermal phase diagrams of quaternary system excellently match with the experimental data.展开更多
Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (...Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (230 ℃, autogenous pressure, batch reactor). The initial surface-specific activities for ethylene glycol reforming were in a similar range but decreased in the order of Pt (15.5 h-1 ) 〉Co(13.0 h 1 ) 〉Ni(5.2 h-1) while the Cu catalyst only showed low dehydrogenation activity. The hydrogen molar selectivity decreased in the order of Pt (53%)〉Co(21%)〉Ni (15%) as a result of the production of methane over the latter two catalysts. Over the Co catalyst acids were formed in the liquid phase while alcohols were formed over Ni and Pt. Due to the low pH of the reaction mixture, especially in the case of Co (as a result of the formed acids), significant cobalt leaching occurs which resulted in a rapid deactivation of this catalyst. Investigations of the spent catalysts with various techniques showed that metal particle growth is responsible for the deactivation of the Pt and Ni catalysts. In addition, coking might also contribute to the deactivation of the Ni catalyst.展开更多
Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan...Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan has affected their development.Herein,we report a metallic vanadium trioxide material intercalated with phase transformation as cathode applied in aqueous zinc-ion batteries.It offers satisfactory electrochemical performances with a high specific capacity(435 mAh g^(-1) at 0.5 A g^(-1)),decent power density(5.23 kW kg^(-1))and desired energy density(331 Wh kg^(-1)),as well as good cyclability.The superior performance originates from the stable structure and fast Zn^(2+)diffusion,enabled by the pre-intercalation of Zn^(2+)and water molecules.展开更多
By using microwave-assisted co-precipitation in aqueous phase, adding surface activation agent PEG-6000 into the mixture of InCl3 solution and SnCl4 solution, and dropping the ammonia solution with the density (volume...By using microwave-assisted co-precipitation in aqueous phase, adding surface activation agent PEG-6000 into the mixture of InCl3 solution and SnCl4 solution, and dropping the ammonia solution with the density (volume ratio) of 1-0 to 1-4, ITO precursor was prepared at different reaction system temperatures of 35 ℃-85 ℃, then ITO nano-powder was obtained after it was calcinated at 800 ℃ for 1 h. The morphology of ITO nano-powder was characterized by SEM and its electrical conductivity was determined by conductivity meter. The effects of different temperatures and ammonia concentration in microwave-assisted reaction system on its morphology and electric conductivity were discussed. The experimental results indicate that with the dilution of the ammonia solution or the rise of reacting system temperature, the morphology of ITO particles is transformed from spherical to rod-like one with the decline of its electric conductivity. And the electric conductivity of ITO nano-powders with spherical morphology is higher than that of ITO nano-powders with rod-like morphology.展开更多
The interesting phenopmena of two aqueous phases coexisting in dilute aqueous solutions of sodium undecenoate-dodecyltrimethylammo brodride ndxture and sodium laurate-dodecyltrimethylammonium brondde mixture were inve...The interesting phenopmena of two aqueous phases coexisting in dilute aqueous solutions of sodium undecenoate-dodecyltrimethylammo brodride ndxture and sodium laurate-dodecyltrimethylammonium brondde mixture were investigated. Vesicles existing in both phases were shown by TEM images. The vesicles are dispersed in lower phase and flocculated in upper phase. Multilamellar structure of vesicles was found in the upper phase of sodium laurate-dodecyltrimethylammonium bromide system.展开更多
Aqueous zinc-ion batteries have been regarded as a promising alternative to large-scale energy storage, due to associated low-cost, improved safety and environmental friendliness. However, a high-performance cathode m...Aqueous zinc-ion batteries have been regarded as a promising alternative to large-scale energy storage, due to associated low-cost, improved safety and environmental friendliness. However, a high-performance cathode material for both rate capability and specific capacity is still a challenge. One kind of the more promising candidates are sodium manganese oxide(NMO) materials, although they suffer from individual issues and need to be further improved. Herein, we present a novel mixed phase NMO material composed of nearly equal amounts of Na(0.55)Mn2O4 and Na(0.7)MnO(2.05). The structured configuration with particle size of 200–500 nm is found to be beneficial towards improving the ion diffusion rate during the charge/discharge process. Compared with Na(0.7)MnO(2.05) and Na(0.55)Mn2O4, the mixed phase NMO demonstrates an enhanced rate capability and excellent long-term cycling stability with a capacity retention of 83% after 800 cycles. More importantly, the system also delivers an impressive energy density and power density, as 378 W·h·kg^-1 at 68.7 W·kg^-1, or 172 W·h·kg^-1 at 1705 W·kg^-1. The superior electrochemical performance is ascribed to the fast Zn^2+ diffusion rate because of a large ratio of capacitive contribution(63.9% at 0.9 m V·s^-1). Thus, the mixed phase route provides a novel strategy to enhance electrochemical performance, enabling mixed phase NMO as very promising material towards large-scale energy-storage applications.展开更多
1 Introduction Alkaline lakes are widely distributed in the area of the Qinghai-Tibet Plateau.Most of the salt lakes are famous for their high concentration of lithium,potassium,magnesium,boron(Ma,2000).In recent year...1 Introduction Alkaline lakes are widely distributed in the area of the Qinghai-Tibet Plateau.Most of the salt lakes are famous for their high concentration of lithium,potassium,magnesium,boron(Ma,2000).In recent years,as a new energy material,lithium and its compounds are widely used in the new area,such as aerospace industry,nuclear展开更多
The deactivation behavior by crystallite growth of nickel nanoparticles on various supports(carbon nanofibers, zirconia, Si C, α-Al2O3 and γ-Al2O3) was investigated in the aqueous phase reforming of ethylene glyco...The deactivation behavior by crystallite growth of nickel nanoparticles on various supports(carbon nanofibers, zirconia, Si C, α-Al2O3 and γ-Al2O3) was investigated in the aqueous phase reforming of ethylene glycol. Supported Ni catalysts of ~10 wt% were prepared by impregnation of carbon nanofibers(CNF),Zr O2, SiC, γ-Al2O3 and α-Al2O3. The extent of the Ni nanoparticle growth on various support materials follows the order CNF ~ ZrO2〉 SiC 〉 γ-Al2O3〉〉 α-Al2O3 which sequence, however, was determined by the initial Ni particle size. Based on the observed nickel leaching and the specific growth characteristics; the particle size distribution and the effect of loading on the growth rate, Ostwald ripening is suggested to be the main mechanism contributing to nickel particle growth. Remarkably, initially smaller Ni particles(~12 nm) supported on α-Al2O3 were found to outgrow Ni particles with initially larger size(~20 nm). It is put forward that the higher susceptibility with respect to oxidation of the smaller Ni nanoparticles and differences in initial particle size distribution are responsible for this behavior.展开更多
Aqueous phase reforming (APR) of biomass derived feedstock producing hydrogen was reviewed. The APR process was discussed based on different feedstock categories such as sugars, polyols and ethanol. The mechanism of A...Aqueous phase reforming (APR) of biomass derived feedstock producing hydrogen was reviewed. The APR process was discussed based on different feedstock categories such as sugars, polyols and ethanol. The mechanism of APR was analyzed referring to different structures of feedstock. The reaction pathways of APR were investigated. The usage of catalysts should be judged by feedstock on the requirement including C-C bond cleavage, water-gas shift (WGS) reaction, and catalyst maintenance. The prospects were concluded based on the recent works from bimetallic catalysts and high efficient supports. Examples of significant challenges of reducing catalyst cost and increasing catalyst stability have been discussed. The modification and utilization of alkane selectivity of APR processes for liquid fuel production was also investigated.展开更多
The surface active water-soluble phosphine, P[p-C6H4O(CH2CH2O)nH]3, n=4, is used to generate an squeous rhoditun catalyst for the hydroformylation of dodecene-1. Under I00℃, 5.0 MPa (CO/H2=1∶1 ), pH=6.5, and reachon...The surface active water-soluble phosphine, P[p-C6H4O(CH2CH2O)nH]3, n=4, is used to generate an squeous rhoditun catalyst for the hydroformylation of dodecene-1. Under I00℃, 5.0 MPa (CO/H2=1∶1 ), pH=6.5, and reachon time 4h, the conversion of dodecene-1 was 96.0%, the yield for aldehyde was 84.0%. and n/i =1.8. The catalyst can be reused for more than four times without any appreciable loss in activity and selechvity.展开更多
This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alteraatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum ...This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alteraatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum dots synthesized by aqueous phase. The research results indicate that the fluorescent characteristic of water- solution sample prepared from Na2 SO3 precursor was sensitive to water bath heating time, and specially, its photohuninescence spectrum shows the unique phenomenon of double excitation and emission peaks. Meanwhile, the fluorescent characteristic of water- solution sample prepared from NaBH4 precursor is slightly influenced by water bath heating time, and the sugface of CdSe quantum dots could be passivated by the excessive amount of NaBH4 precursor, which results in the effective decrease of surface traps and great enhancement of quantum yield. Furthermore, the fluorescent emission peaks of samples could be sharpened by vacuum heat-treating process, with its spectral full width at half of maximum (FWHM) around 30- 40 run, so the emission peaks become redshifi, of which the intensity greatly increases.展开更多
A laser flash photolysis study of the reactivity of Cl˙with glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was ca...A laser flash photolysis study of the reactivity of Cl˙with glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was carried out. The obtained rate constants can be used for atmospheric modeling.展开更多
The present work explores the reaction pathways of γ-valerolactone(GVL) over a supported ruthenium catalyst. The conversion of GVL in aqueous phase over a 5% Ru/C catalyst was investigated in a batch reactor operatin...The present work explores the reaction pathways of γ-valerolactone(GVL) over a supported ruthenium catalyst. The conversion of GVL in aqueous phase over a 5% Ru/C catalyst was investigated in a batch reactor operating at 463 K under 500–1000 psi of H2. The main reaction products obtained under these conditions were 2-butanol(2-BuOH), 1,4-pentanediol(1,4-PDO), 2-methyltetrahydrofuran(2-MTHF) and 2-pentanol(2-PeOH). A complete reaction network was developed, identifying the primary and/or secondary products. In this reaction network, production of 2-BuOH via decarbonylation of a ring-opened surface intermediate CH3CH(O*)–(CH2)2–CO*is clearly the dominant pathway. From the evolution of products as a function of reaction time and theoretical(DFT) calculations, a mechanism for the formation of intermediates and products is proposed. The high sensitivity of 2-BuOH production to the presence of CO, compared to a much lower effect on the production of the other products indicates that the sites responsible for decarbonylation are particularly prone to CO adsorption and poisoning. Also, since the decarbonylation rate is not affected by the H2 pressure it is concluded that the direct decarbonylation path of the CH3CH(O*)–(CH2)2–CO*intermediate does not required a previous dehydrogenation step, as is the case in decarbonylation of short alcohols.展开更多
Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH, o-NH_2,o-NHPh)have been conveniently prepared by the reaction of (RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acid in aqueo...Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH, o-NH_2,o-NHPh)have been conveniently prepared by the reaction of (RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acid in aqueous solution containing acetylacetone.The carboxylate ligands in the complexes coordinate to titanium atom in monodentate mode.展开更多
Monomeric anthocyanins exhibit color variations at different pH, but they are highly unstable at physiological pH. To improve the stability, the effects of polyvinylalcohol on the anthocyanins of young red wine prepar...Monomeric anthocyanins exhibit color variations at different pH, but they are highly unstable at physiological pH. To improve the stability, the effects of polyvinylalcohol on the anthocyanins of young red wine prepared from Cambell Early grapes were examined in aqueous solution and in the solid phase on a cotton swab? and inert materials. Cyanidin-3-glucoside and mal-vidin-3-glucoside represented approximately 43.6% of total anthocyanins in the red wine. The anthocyanins decreased to 11.3% of the initial amount in aqueous solution at physiological pH after storage for 60 days at room temperature. On the other hand, from 66.9% to 87.2% remained in the solid phase on a cotton swab? and polypropylene membrane in the presence of polyvinylalcohol. The stability of the anthocyanins increased with the concentration of polyvinyl-alcohol in the solid phase but not in the aqueous solution. The anthocyanins were found to be condensed and immobilized in the complexes of anthocyanins and polyvinylalcohol on the poly-propylene membrane by phase-contrast microscopy analysis. The anthocyanins in the cotton swab? displayed color variations when dipped into different pH buffer solutions. These results suggest that anthocyanins from red wine stabilized in the solid phase by polyvinylalcohol can be used as a visual indicator of pH.展开更多
1 Introduction Salt lakes are widely distributed in the western of China,especially in the area of Qinghai-Xizang(Tibet)Plateau.A series of salt lakes in the Qaidam Basin,located in Qinghai Province,China,is famous fo...1 Introduction Salt lakes are widely distributed in the western of China,especially in the area of Qinghai-Xizang(Tibet)Plateau.A series of salt lakes in the Qaidam Basin,located in Qinghai Province,China,is famous for their abundance of lithium,potassium and boron resources(Zheng et al,1988;Deng et al,2012).It is well known that the展开更多
Glycerol is the main byproduct from the production of biodiesel by transesterification of vegetable oils, and approximately 10% of total biodiesel production volume corresponds to glycerol. The profitability of variou...Glycerol is the main byproduct from the production of biodiesel by transesterification of vegetable oils, and approximately 10% of total biodiesel production volume corresponds to glycerol. The profitability of various chemical processes depends, in part, on the sale of byproducts, which enables a reduction in the production costs and consequently, in the product’s final price. Thus, it is necessary to look for alternatives to solve the problem of glycerol buildup, in order to avoid future environmental impacts and make biodiesel competitive in the growing market of biofuels. In this context, this study’s objective is the development of a low cost and environmental clean technology that allows the conversion of glycerin into a greater value product. In this paper, an economic evaluation of production hydrogen using Aqueous Phase Reforming (APR) was conducted. Firstly, we detailed the technical assumptions in the study. Reactions were performed in batch reformer of 10 liters of capacity, at the temperature of 250℃ and pressure of 38 atm. Finally, a sensitivity analysis was performed. The results from economic evaluation show that APR of glycerol, using nickel catalysts supported on alumina or zirconium oxide, is a promising and competitive technology for hydrogen production.展开更多
基金supported financially by the Natural Science Foundation of Shandong Province,China(grant numbers ZR2020QE067,ZR2020QB117,and ZR2022MB143)the New Colleges and Universities Twenty Foundational Projects of Jinan City,China(grant number 2021GXRC068)+2 种基金the National Natural Science Foundation of China,China(grant number 22208174)The Scientific Research Foundation in Qilu University of Technology(Shandong Academy of Sciences),China(grant numbers 2023PY002)The Talent research project of Qilu University of Technology(Shandong Academy of Sciences),China(grant numbers 2023RCKY013)。
文摘Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity,sluggish ion kinetics,and severe volume expansion during the insertion/extraction process of Zn^(2+).Herein,a series of V_(2)O_(3)nanospheres embedded N-doped carbon nanofiber structures with various V_(2)O_(3)spherical morphologies(solid,core-shell,hollow)have been designed for the first time by an electrospinning technique followed thermal treatments.The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability,but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V_(2)O_(3)particles.Furthermore,the varied morphological structures of V_(2)O_(3)with abundant oxygen vacancies can alleviate the volume change and increase the Zn^(2+)pathway.Besides,the phase transition between V_(2)O_(3)and Zn_XV_(2)O_(5-m)·n H_(2)O in the cycling was also certified.As a result,the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells,which is also confirmed through density functional theory(DFT)calculations.Even assembled into flexible ZIBs,the sample still exhibits superior electrochemical performance,which may afford new design concept for flexible cathode materials of ZIBs.
基金Supported by National Natural Science Foundation of China
文摘Partition coefficients of Urokinase(UK)were measured in aqueous two-phase systems con-taining polyethylene glycol and potassium phosphate at 273.2K.Based on the Diamond-Hsu model,a modified expression was obtained for the correlation of enzyme partitioning in theabove-mentioned systems.Utilizing a modified form,the partitioning data of UK and heteroproteinwere correlated.The results show that the modified model is simple gives good precision.and will fa-cilitate engineering scale-up of aqueous two-phase systems for certain proteins purification.
基金financial support of the National Natural Science Foundation of China(U1407204,U1707602)the Yangtze Scholars and Innovative Research Team in University of Education of China+1 种基金the Innovative Research Team of Tianjin Municipal Education Commission(TD12-5004)Foundation of Tianjin Key Laboratory of Marine Resources and Chemistry(201602)。
文摘Salt lake brine is a complex salt-water system under natural environment.Although many models can express the thermodynamic properties and phase equilibrium of electrolyte aqueous solution,the multi-temperature characteristics and predictability are still the goals of model development.In this study,a comprehensive thermodynamic model system is re-established based on the eNRTL model and some improvements:(1) new expression of long-range electrostatic term with symmetrical reference state is proposed to handle the electrolyte solution covering entire concentration range;(2) the temperature dependence of the binary interaction parameters is formulated with a Gibbs Helmholtz expression containing three temperature coefficients,the liquid parameters,which associated with Gibbs energy,enthalpy,and heat capacity contribution;and(3) liquid parameters and solid species data are regressed from properties and solubility data at full temperature range.Together the activity coefficient model,property models and parameters of liquid and solid offer a comprehensive thermodynamic model system for the typical bittern of MgCl2-CaCl2-H2 O binary and ternary systems,and it shows excellent agreement with the literature data for the ternary and binary systems.The successful prediction of complete phase diagram of ternary system shows that the model has the ability to deal with high concentration and high non-idealitv system,and the ability to extrapolate the temperature.
基金financial support of the National Natural Science Foundation of China(U1707602,U1407204)Yangtze Scholars and Innovative Research Team in University of Education of China,the Innovative Research Team of Tianjin Municipal Education Commission(TD125004)。
文摘It is still a challenging task to accurately and temperature-continuously express the thermodynamic properties and phase equilibrium behaviors of the salt-lake brine with multi-component,multitemperature and high concentration.The essential subsystem of sulfate type brine,aqueous Li^(+)-Na^(+)-K^(+)-SO_(4)^(2-) and its subsystems across a temperature range from 250 K to 643 K are investigated with the improved comprehensive thermodynamic model.Liquid parameters(Δg_(IJ),Δh_(IJ),and ΔC_(p,IJ))associated with the contributions of Gibbs energy,enthalpy,and heat capacity to the binary interaction parameters,i.e.the temperature coefficients of eNRTL parameters formulated with a Gibbs Helmholtz expression,are determined via multi-objective optimization method.The solid constantsΔ_(f)G_(k)°^((298.15))andΔ_(f)H_(k)°^((298.15))of11 solid species occurred in the quaternary system are rebuilt from multi-temperature solubilities.The modeling results show the accurate representation of(1)solution properties and binary phase diagram at temperature ranges from eutectic points to 643 K;(2)isothermal phase diagrams for Li_(2)SO_(4)-Na_(2)SO_(4)-H_(2)O,Li_(2)SO_(4)-K_(2)SO_(4)-H_(2)O and Na_(2)SO_(4)-K_(2)SO_(4)-H_(2)O ternary systems.The predicted results of complete structure and polythermal phase diagram of ternary systems and the isothermal phase diagrams of quaternary system excellently match with the experimental data.
基金supported by the Smart Mix Program of the Netherlands Ministry of Economic Affairs and the Netherlands Ministry of Education, Culture and Science
文摘Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (230 ℃, autogenous pressure, batch reactor). The initial surface-specific activities for ethylene glycol reforming were in a similar range but decreased in the order of Pt (15.5 h-1 ) 〉Co(13.0 h 1 ) 〉Ni(5.2 h-1) while the Cu catalyst only showed low dehydrogenation activity. The hydrogen molar selectivity decreased in the order of Pt (53%)〉Co(21%)〉Ni (15%) as a result of the production of methane over the latter two catalysts. Over the Co catalyst acids were formed in the liquid phase while alcohols were formed over Ni and Pt. Due to the low pH of the reaction mixture, especially in the case of Co (as a result of the formed acids), significant cobalt leaching occurs which resulted in a rapid deactivation of this catalyst. Investigations of the spent catalysts with various techniques showed that metal particle growth is responsible for the deactivation of the Pt and Ni catalysts. In addition, coking might also contribute to the deactivation of the Ni catalyst.
基金financially supported by the National Natural Science Foundation of China(51872139,51902158,and 51903121)the Recruitment Program of Global Experts(1211019)+2 种基金the“Six Talent Peak”Project of Jiangsu Province(XCL-043,XCL-021 and XCL-018)the Natural Science Foundation of Jiangsu Higher Education Institutions(19KJB430002 and 18KJB150016)the start-up fund from Nanjing Tech University(3983500197 and 3827401784)。
文摘Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan has affected their development.Herein,we report a metallic vanadium trioxide material intercalated with phase transformation as cathode applied in aqueous zinc-ion batteries.It offers satisfactory electrochemical performances with a high specific capacity(435 mAh g^(-1) at 0.5 A g^(-1)),decent power density(5.23 kW kg^(-1))and desired energy density(331 Wh kg^(-1)),as well as good cyclability.The superior performance originates from the stable structure and fast Zn^(2+)diffusion,enabled by the pre-intercalation of Zn^(2+)and water molecules.
基金Project (50725416) supported by the National Science Fund for Distinguished Young Scholars of ChinaProject(2008RS4037) supported by the Postdoctoral Science and Research Special Foundation of Hunan Province, ChinaProject supported by the Postdoctoral Science Foundation of Central South University, China
文摘By using microwave-assisted co-precipitation in aqueous phase, adding surface activation agent PEG-6000 into the mixture of InCl3 solution and SnCl4 solution, and dropping the ammonia solution with the density (volume ratio) of 1-0 to 1-4, ITO precursor was prepared at different reaction system temperatures of 35 ℃-85 ℃, then ITO nano-powder was obtained after it was calcinated at 800 ℃ for 1 h. The morphology of ITO nano-powder was characterized by SEM and its electrical conductivity was determined by conductivity meter. The effects of different temperatures and ammonia concentration in microwave-assisted reaction system on its morphology and electric conductivity were discussed. The experimental results indicate that with the dilution of the ammonia solution or the rise of reacting system temperature, the morphology of ITO particles is transformed from spherical to rod-like one with the decline of its electric conductivity. And the electric conductivity of ITO nano-powders with spherical morphology is higher than that of ITO nano-powders with rod-like morphology.
文摘The interesting phenopmena of two aqueous phases coexisting in dilute aqueous solutions of sodium undecenoate-dodecyltrimethylammo brodride ndxture and sodium laurate-dodecyltrimethylammonium brondde mixture were investigated. Vesicles existing in both phases were shown by TEM images. The vesicles are dispersed in lower phase and flocculated in upper phase. Multilamellar structure of vesicles was found in the upper phase of sodium laurate-dodecyltrimethylammonium bromide system.
基金the financial support from the China Scholarship Council(CSC)supported by the National Natural Science Foundation of China(21905037)the Fundamental Research Funds for the Central Universities(3132019328,3132020151)。
文摘Aqueous zinc-ion batteries have been regarded as a promising alternative to large-scale energy storage, due to associated low-cost, improved safety and environmental friendliness. However, a high-performance cathode material for both rate capability and specific capacity is still a challenge. One kind of the more promising candidates are sodium manganese oxide(NMO) materials, although they suffer from individual issues and need to be further improved. Herein, we present a novel mixed phase NMO material composed of nearly equal amounts of Na(0.55)Mn2O4 and Na(0.7)MnO(2.05). The structured configuration with particle size of 200–500 nm is found to be beneficial towards improving the ion diffusion rate during the charge/discharge process. Compared with Na(0.7)MnO(2.05) and Na(0.55)Mn2O4, the mixed phase NMO demonstrates an enhanced rate capability and excellent long-term cycling stability with a capacity retention of 83% after 800 cycles. More importantly, the system also delivers an impressive energy density and power density, as 378 W·h·kg^-1 at 68.7 W·kg^-1, or 172 W·h·kg^-1 at 1705 W·kg^-1. The superior electrochemical performance is ascribed to the fast Zn^2+ diffusion rate because of a large ratio of capacitive contribution(63.9% at 0.9 m V·s^-1). Thus, the mixed phase route provides a novel strategy to enhance electrochemical performance, enabling mixed phase NMO as very promising material towards large-scale energy-storage applications.
基金Financial support from the NSFCs (21106103, 21276194 and 21306136)the Specialized Research Funds for the Doctoral Program of Chinese Higher Education (20101208110003 and 20111208120003)+1 种基金the Natural Science Foundation of Tianjin (12JCQNJC03400)the Senior Professor Program for TUST (20100405)
文摘1 Introduction Alkaline lakes are widely distributed in the area of the Qinghai-Tibet Plateau.Most of the salt lakes are famous for their high concentration of lithium,potassium,magnesium,boron(Ma,2000).In recent years,as a new energy material,lithium and its compounds are widely used in the new area,such as aerospace industry,nuclear
基金the support of the Smart Mix Program of The Netherlands Ministry of Economic Affairs, Agriculture and Innovation and The Netherlands Ministry of Education, Culture and Science (Grant no. 053.70.011)
文摘The deactivation behavior by crystallite growth of nickel nanoparticles on various supports(carbon nanofibers, zirconia, Si C, α-Al2O3 and γ-Al2O3) was investigated in the aqueous phase reforming of ethylene glycol. Supported Ni catalysts of ~10 wt% were prepared by impregnation of carbon nanofibers(CNF),Zr O2, SiC, γ-Al2O3 and α-Al2O3. The extent of the Ni nanoparticle growth on various support materials follows the order CNF ~ ZrO2〉 SiC 〉 γ-Al2O3〉〉 α-Al2O3 which sequence, however, was determined by the initial Ni particle size. Based on the observed nickel leaching and the specific growth characteristics; the particle size distribution and the effect of loading on the growth rate, Ostwald ripening is suggested to be the main mechanism contributing to nickel particle growth. Remarkably, initially smaller Ni particles(~12 nm) supported on α-Al2O3 were found to outgrow Ni particles with initially larger size(~20 nm). It is put forward that the higher susceptibility with respect to oxidation of the smaller Ni nanoparticles and differences in initial particle size distribution are responsible for this behavior.
文摘Aqueous phase reforming (APR) of biomass derived feedstock producing hydrogen was reviewed. The APR process was discussed based on different feedstock categories such as sugars, polyols and ethanol. The mechanism of APR was analyzed referring to different structures of feedstock. The reaction pathways of APR were investigated. The usage of catalysts should be judged by feedstock on the requirement including C-C bond cleavage, water-gas shift (WGS) reaction, and catalyst maintenance. The prospects were concluded based on the recent works from bimetallic catalysts and high efficient supports. Examples of significant challenges of reducing catalyst cost and increasing catalyst stability have been discussed. The modification and utilization of alkane selectivity of APR processes for liquid fuel production was also investigated.
文摘The surface active water-soluble phosphine, P[p-C6H4O(CH2CH2O)nH]3, n=4, is used to generate an squeous rhoditun catalyst for the hydroformylation of dodecene-1. Under I00℃, 5.0 MPa (CO/H2=1∶1 ), pH=6.5, and reachon time 4h, the conversion of dodecene-1 was 96.0%, the yield for aldehyde was 84.0%. and n/i =1.8. The catalyst can be reused for more than four times without any appreciable loss in activity and selechvity.
文摘This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alteraatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum dots synthesized by aqueous phase. The research results indicate that the fluorescent characteristic of water- solution sample prepared from Na2 SO3 precursor was sensitive to water bath heating time, and specially, its photohuninescence spectrum shows the unique phenomenon of double excitation and emission peaks. Meanwhile, the fluorescent characteristic of water- solution sample prepared from NaBH4 precursor is slightly influenced by water bath heating time, and the sugface of CdSe quantum dots could be passivated by the excessive amount of NaBH4 precursor, which results in the effective decrease of surface traps and great enhancement of quantum yield. Furthermore, the fluorescent emission peaks of samples could be sharpened by vacuum heat-treating process, with its spectral full width at half of maximum (FWHM) around 30- 40 run, so the emission peaks become redshifi, of which the intensity greatly increases.
文摘A laser flash photolysis study of the reactivity of Cl˙with glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was carried out. The obtained rate constants can be used for atmospheric modeling.
基金the Department of Energy for funding the experimental part of this work under grant DE-SC0004600the theoretical part under grant DE-EE0006287 of the Bioenergy Technology Office CHASE program
文摘The present work explores the reaction pathways of γ-valerolactone(GVL) over a supported ruthenium catalyst. The conversion of GVL in aqueous phase over a 5% Ru/C catalyst was investigated in a batch reactor operating at 463 K under 500–1000 psi of H2. The main reaction products obtained under these conditions were 2-butanol(2-BuOH), 1,4-pentanediol(1,4-PDO), 2-methyltetrahydrofuran(2-MTHF) and 2-pentanol(2-PeOH). A complete reaction network was developed, identifying the primary and/or secondary products. In this reaction network, production of 2-BuOH via decarbonylation of a ring-opened surface intermediate CH3CH(O*)–(CH2)2–CO*is clearly the dominant pathway. From the evolution of products as a function of reaction time and theoretical(DFT) calculations, a mechanism for the formation of intermediates and products is proposed. The high sensitivity of 2-BuOH production to the presence of CO, compared to a much lower effect on the production of the other products indicates that the sites responsible for decarbonylation are particularly prone to CO adsorption and poisoning. Also, since the decarbonylation rate is not affected by the H2 pressure it is concluded that the direct decarbonylation path of the CH3CH(O*)–(CH2)2–CO*intermediate does not required a previous dehydrogenation step, as is the case in decarbonylation of short alcohols.
文摘Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH, o-NH_2,o-NHPh)have been conveniently prepared by the reaction of (RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acid in aqueous solution containing acetylacetone.The carboxylate ligands in the complexes coordinate to titanium atom in monodentate mode.
文摘Monomeric anthocyanins exhibit color variations at different pH, but they are highly unstable at physiological pH. To improve the stability, the effects of polyvinylalcohol on the anthocyanins of young red wine prepared from Cambell Early grapes were examined in aqueous solution and in the solid phase on a cotton swab? and inert materials. Cyanidin-3-glucoside and mal-vidin-3-glucoside represented approximately 43.6% of total anthocyanins in the red wine. The anthocyanins decreased to 11.3% of the initial amount in aqueous solution at physiological pH after storage for 60 days at room temperature. On the other hand, from 66.9% to 87.2% remained in the solid phase on a cotton swab? and polypropylene membrane in the presence of polyvinylalcohol. The stability of the anthocyanins increased with the concentration of polyvinyl-alcohol in the solid phase but not in the aqueous solution. The anthocyanins were found to be condensed and immobilized in the complexes of anthocyanins and polyvinylalcohol on the poly-propylene membrane by phase-contrast microscopy analysis. The anthocyanins in the cotton swab? displayed color variations when dipped into different pH buffer solutions. These results suggest that anthocyanins from red wine stabilized in the solid phase by polyvinylalcohol can be used as a visual indicator of pH.
基金Financial support from the NSFCs (21106103, 21276194 and 21306136)the Specialized Research Funds for the Doctoral Program of Chinese Higher Education (20101208110003, 20111208120003)+1 种基金the Natural Science Foundation of Tianjin (12JCQNJC03400)Senior Professor Program for TUST (20100405)
文摘1 Introduction Salt lakes are widely distributed in the western of China,especially in the area of Qinghai-Xizang(Tibet)Plateau.A series of salt lakes in the Qaidam Basin,located in Qinghai Province,China,is famous for their abundance of lithium,potassium and boron resources(Zheng et al,1988;Deng et al,2012).It is well known that the
文摘Glycerol is the main byproduct from the production of biodiesel by transesterification of vegetable oils, and approximately 10% of total biodiesel production volume corresponds to glycerol. The profitability of various chemical processes depends, in part, on the sale of byproducts, which enables a reduction in the production costs and consequently, in the product’s final price. Thus, it is necessary to look for alternatives to solve the problem of glycerol buildup, in order to avoid future environmental impacts and make biodiesel competitive in the growing market of biofuels. In this context, this study’s objective is the development of a low cost and environmental clean technology that allows the conversion of glycerin into a greater value product. In this paper, an economic evaluation of production hydrogen using Aqueous Phase Reforming (APR) was conducted. Firstly, we detailed the technical assumptions in the study. Reactions were performed in batch reformer of 10 liters of capacity, at the temperature of 250℃ and pressure of 38 atm. Finally, a sensitivity analysis was performed. The results from economic evaluation show that APR of glycerol, using nickel catalysts supported on alumina or zirconium oxide, is a promising and competitive technology for hydrogen production.