Niobium was electrodeposited on 316 stainless steel bipolar plates of a fuel cell in water and air-stable choline chloride based ionic liquids. The electrochemical corruption property of bipolar plates in simulated PE...Niobium was electrodeposited on 316 stainless steel bipolar plates of a fuel cell in water and air-stable choline chloride based ionic liquids. The electrochemical corruption property of bipolar plates in simulated PEMFC environment was investigated. It was showed that the plating film was distributed on the surface of 316 stainless steel like isolated islands with height less than 50 nm. The XPS, XRD results showed that a smooth and strong chemical inert film of Nb O and Nb2O5 was formed on the surface of 316 stainless steel. In simulated cathodic condition, the corrosion potential of Nb coated stainless steel was improved by 244 m V, whilst in an anodic condition, it was improved by 105 m V. The current densities for the coated 316 stainless steel were decreased to 2.479 4 μA·cm-2 from 14.810 μA·cm-2 at-0.1 V and to 0.576 μA·cm-2 from 13.417 μA/·cm-2 at 0.6 V, respectively. It was implied that the niobium coating effectively decreased the corrosion rate. The results of the electrochemical tests indicated that the corrosion resistance of stainless steel was greatly improved after coated with niobium.展开更多
Solubilities of CO_2, CH_4, H_2, CO and N_2 in choline chloride/urea(ChCl/Urea) were investigated at temperatures ranging from 308.2 to328.2 K and pressures ranging from 0.6 to 4.6 MPa. The results show that the solub...Solubilities of CO_2, CH_4, H_2, CO and N_2 in choline chloride/urea(ChCl/Urea) were investigated at temperatures ranging from 308.2 to328.2 K and pressures ranging from 0.6 to 4.6 MPa. The results show that the solubilities of gases increase with increasing pressure and decreasing temperature. The solubility of CO_2 is higher than that of CH_4, H_2, CO and N_2, which indicates that ChCl/Urea may be used as a potential solvent for CO_2 capture from the gas mixture. Solubility of CO_2 in ChCl/Urea was fitted by Non-Random Two-Liquid and Redlich-Kwong(NRTL-RK) model, and solubility of CH_4, H_2, CO or N_2 in ChCl/Urea was fitted by Henry's Law. The standard enthalpy, standard Gibbs energy and standard entropy of gases were calculated. Additionally, the CO_2/CH_4 selectivities in water, dry ChCl/Urea and aqueous ChCl/Urea were further discussed.展开更多
A 2×2×2 factorial design was adopted to study the effects of temperature, moisture and choline chloride on vitamin A stability in premix. The results indicated that temperature, moisture and choline chloride...A 2×2×2 factorial design was adopted to study the effects of temperature, moisture and choline chloride on vitamin A stability in premix. The results indicated that temperature, moisture and choline chloride damaged vitamin A significantly. The regression equations of vitamin A disappearance rate and storage time were as follows： in room temperature （18±3）℃, y=14.368Ln（x）＋ 4.1425, R^2=0.978; in high temperature （4 ℃ ）, y=22.24Ln （x）＋13.27, R^2=0.9918; in low moisture （2%-3%）, y= 10.408Ln （x）＋9.5418, R^2=-0.9322; in high moisture （8%-9%）, y=26.199Ln（x）＋7.8741, R^2=-0.9949; in the condition of choline chloride flee, y=9.5125Ln（x）＋ 8.9869, R^2=0.9826; supplemented with choline chloride, y=27.094Ln （x）＋8.4276, R^2=0.9984. Temperature had highly significant interaction with moisure and choline chloride on destruction of vitamin A, respectively from the periods of two months storage. However, from the period of the first month storage, the interaction of moisture and choline chloride, as well as the interaction of temperature, moisture and choline destroyed vitamin A remarkably.展开更多
The authors prepared,characterized and preliminary studied the properties of some neoteric solvents-ionic liquids based on choline chloride,i.e.,three ionic liquids based on the eutectics of choline chloride（2-hydrox...The authors prepared,characterized and preliminary studied the properties of some neoteric solvents-ionic liquids based on choline chloride,i.e.,three ionic liquids based on the eutectics of choline chloride（2-hydroxyN,N,N-trimethylethanaminium chloride） with,respectively,urea,malonic acid and citric acid.The obtained mixtures were clear and colorless ionic liquids at room temperature.The thermophysical properties,namely,density,viscosity,and electrical conductivity of these mixtures were investigated as a function of temperature within a range of 298-353 K.Correlations for the temperature dependence of the measured properties were generated and discussed in terms of Arrhenius theory.Finally the electrochemical windows of the eutectic liquids were determined.展开更多
The preparation and characterization of homogeneous and colorless ionic liquid analogs（ILAs） containing choline chloride（ChC1）, malonic acid and bismuth chloride were investigated. The structure of the above mixtu...The preparation and characterization of homogeneous and colorless ionic liquid analogs（ILAs） containing choline chloride（ChC1）, malonic acid and bismuth chloride were investigated. The structure of the above mixture was preliminarily analyzed, and then the physicochemieal properties including viscosity, conductivity and density were investigated as functions of temperature and composition. Additionally, the thermal stability of the ILAs and the electrochemical behavior of Bi3＋ ions in the medium were studied. Structure analysis reveals that the synthesis of deep eutectic solvents（DESs） is closely related to the formation of hydrogen bonds between malonic acid and ChC1, with their viscosity, conductivity and density being greatly dependent on the temperature and composition. Thermo- gravimetric analysis demonstrates that the ILAs are very stable between room temperature and 398.15 K. And the electrochemical experiments indicate that the bismuth films can be successfully deposited from this ILAs and the deposition mechanism of bismuth is a rather irreversible process. The surface morphology of bismuth films deposited on Cu substrates was very compact and smooth. Thus, ChCl-malonic acid DESs were shown to be a good alternative to aqueous solvents for various deposition-related applications.展开更多
Deep eutectic solvents(DESs)have gained much attention in the fabrication of advanced nanoelectrocatalysts due to their amazing template function.However,their stabilizing function for easily hydrolyzed inorganic nano...Deep eutectic solvents(DESs)have gained much attention in the fabrication of advanced nanoelectrocatalysts due to their amazing template function.However,their stabilizing function for easily hydrolyzed inorganic nanomaterials is rarely studied.Here,a DES-mediated strategy was reported to synthesize octahedral Ni–Co precursor(NiCo–NH_(3) complex),which could be directly transformed into NiCo_(2)O_(4) nanooctahedrons after thermal decomposition.The NiCo–NH_(3) precursor in octahedral shape was achieved with the DES-mediated crystallization in the choline chloride(ChCl)/glycerol.The ChCl/glycerol DES not only tailored the morphology of the as-prepared precursor by template effect but also inhibited its hydrolysis,ensuring the successful fabrication of octahedral NiCo–NH_(3) complex precursor with high yield.The NiCo–NH_(3) complex precursor was converted to well-defined NiCo_(2)O_(4) nanooctahedrons,where the calcination temperature and time were explored in detail.It revealed that DES could participate in the conversion process to control the morphology of calcination product.The resultant NiCo_(2)O_(4) nanooctahedrons demonstrated excellent electroactivity and remarkable durability for oxygen evolution reaction(OER).The present strategy not only offers an efficient OER electrocatalyst but also enriches the approaches of DESs in designing advanced nanocatalysts.展开更多
In the current work,we are introducing the concept of co-electrolyte in the aqueous medium.Herein,we have prepared the bio-inspired co-electrolyte of choline chloride and potassium hydroxide,which in situ produces cho...In the current work,we are introducing the concept of co-electrolyte in the aqueous medium.Herein,we have prepared the bio-inspired co-electrolyte of choline chloride and potassium hydroxide,which in situ produces choline hydroxide and potassium chloride by the ion-exchange mechanism.The resultant co-electrolyte(RCE)solution exhibits decent electrochemical property than its parental salts,that is,potassium hydroxide,choline chloride.The RCE further used to enhance the energy storage ability of reduced graphene oxide(RGO).The material exhibits maximum specific capacitance 394 F g-1 and higher energy density 44.3 Wh kg-1 at the current density of 1 A g-1 in the presence of co-electrolyte,which is higher as compared to its preceding salts as an electrolyte.Also,the material exhibits lower equivalent series resistance,that is,0.3Ωin RCE.This concept can be considered as future development in the field of energy storage materials.展开更多
A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）...A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）, and hydrazine hydrate（4） in freshly prepared deep eutectic solvent, DES（choline chloride：urea）. This protocol has afforded corresponding pyrano[2,3-F]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.展开更多
基金Funded by the National Natural Science Foundation of China(No.21276036)the Fundamental Research Funds for the Central Universities(No.3132014323)
文摘Niobium was electrodeposited on 316 stainless steel bipolar plates of a fuel cell in water and air-stable choline chloride based ionic liquids. The electrochemical corruption property of bipolar plates in simulated PEMFC environment was investigated. It was showed that the plating film was distributed on the surface of 316 stainless steel like isolated islands with height less than 50 nm. The XPS, XRD results showed that a smooth and strong chemical inert film of Nb O and Nb2O5 was formed on the surface of 316 stainless steel. In simulated cathodic condition, the corrosion potential of Nb coated stainless steel was improved by 244 m V, whilst in an anodic condition, it was improved by 105 m V. The current densities for the coated 316 stainless steel were decreased to 2.479 4 μA·cm-2 from 14.810 μA·cm-2 at-0.1 V and to 0.576 μA·cm-2 from 13.417 μA/·cm-2 at 0.6 V, respectively. It was implied that the niobium coating effectively decreased the corrosion rate. The results of the electrochemical tests indicated that the corrosion resistance of stainless steel was greatly improved after coated with niobium.
基金the Swedish Energy AgencySwedish Research Council in Sweden for financial support
文摘Solubilities of CO_2, CH_4, H_2, CO and N_2 in choline chloride/urea(ChCl/Urea) were investigated at temperatures ranging from 308.2 to328.2 K and pressures ranging from 0.6 to 4.6 MPa. The results show that the solubilities of gases increase with increasing pressure and decreasing temperature. The solubility of CO_2 is higher than that of CH_4, H_2, CO and N_2, which indicates that ChCl/Urea may be used as a potential solvent for CO_2 capture from the gas mixture. Solubility of CO_2 in ChCl/Urea was fitted by Non-Random Two-Liquid and Redlich-Kwong(NRTL-RK) model, and solubility of CH_4, H_2, CO or N_2 in ChCl/Urea was fitted by Henry's Law. The standard enthalpy, standard Gibbs energy and standard entropy of gases were calculated. Additionally, the CO_2/CH_4 selectivities in water, dry ChCl/Urea and aqueous ChCl/Urea were further discussed.
基金Supported by National Basic Research Program(2004CB11750-5)
文摘A 2×2×2 factorial design was adopted to study the effects of temperature, moisture and choline chloride on vitamin A stability in premix. The results indicated that temperature, moisture and choline chloride damaged vitamin A significantly. The regression equations of vitamin A disappearance rate and storage time were as follows： in room temperature （18±3）℃, y=14.368Ln（x）＋ 4.1425, R^2=0.978; in high temperature （4 ℃ ）, y=22.24Ln （x）＋13.27, R^2=0.9918; in low moisture （2%-3%）, y= 10.408Ln （x）＋9.5418, R^2=-0.9322; in high moisture （8%-9%）, y=26.199Ln（x）＋7.8741, R^2=-0.9949; in the condition of choline chloride flee, y=9.5125Ln（x）＋ 8.9869, R^2=0.9826; supplemented with choline chloride, y=27.094Ln （x）＋8.4276, R^2=0.9984. Temperature had highly significant interaction with moisure and choline chloride on destruction of vitamin A, respectively from the periods of two months storage. However, from the period of the first month storage, the interaction of moisture and choline chloride, as well as the interaction of temperature, moisture and choline destroyed vitamin A remarkably.
文摘The authors prepared,characterized and preliminary studied the properties of some neoteric solvents-ionic liquids based on choline chloride,i.e.,three ionic liquids based on the eutectics of choline chloride（2-hydroxyN,N,N-trimethylethanaminium chloride） with,respectively,urea,malonic acid and citric acid.The obtained mixtures were clear and colorless ionic liquids at room temperature.The thermophysical properties,namely,density,viscosity,and electrical conductivity of these mixtures were investigated as a function of temperature within a range of 298-353 K.Correlations for the temperature dependence of the measured properties were generated and discussed in terms of Arrhenius theory.Finally the electrochemical windows of the eutectic liquids were determined.
基金Supported by the Natural Science Foundation of Tianjin City, China（No. 15JCQNJC05900）.
文摘The preparation and characterization of homogeneous and colorless ionic liquid analogs（ILAs） containing choline chloride（ChC1）, malonic acid and bismuth chloride were investigated. The structure of the above mixture was preliminarily analyzed, and then the physicochemieal properties including viscosity, conductivity and density were investigated as functions of temperature and composition. Additionally, the thermal stability of the ILAs and the electrochemical behavior of Bi3＋ ions in the medium were studied. Structure analysis reveals that the synthesis of deep eutectic solvents（DESs） is closely related to the formation of hydrogen bonds between malonic acid and ChC1, with their viscosity, conductivity and density being greatly dependent on the temperature and composition. Thermo- gravimetric analysis demonstrates that the ILAs are very stable between room temperature and 398.15 K. And the electrochemical experiments indicate that the bismuth films can be successfully deposited from this ILAs and the deposition mechanism of bismuth is a rather irreversible process. The surface morphology of bismuth films deposited on Cu substrates was very compact and smooth. Thus, ChCl-malonic acid DESs were shown to be a good alternative to aqueous solvents for various deposition-related applications.
基金supported by National Natural Science Foundation of China(Grant No.22073057).
文摘Deep eutectic solvents(DESs)have gained much attention in the fabrication of advanced nanoelectrocatalysts due to their amazing template function.However,their stabilizing function for easily hydrolyzed inorganic nanomaterials is rarely studied.Here,a DES-mediated strategy was reported to synthesize octahedral Ni–Co precursor(NiCo–NH_(3) complex),which could be directly transformed into NiCo_(2)O_(4) nanooctahedrons after thermal decomposition.The NiCo–NH_(3) precursor in octahedral shape was achieved with the DES-mediated crystallization in the choline chloride(ChCl)/glycerol.The ChCl/glycerol DES not only tailored the morphology of the as-prepared precursor by template effect but also inhibited its hydrolysis,ensuring the successful fabrication of octahedral NiCo–NH_(3) complex precursor with high yield.The NiCo–NH_(3) complex precursor was converted to well-defined NiCo_(2)O_(4) nanooctahedrons,where the calcination temperature and time were explored in detail.It revealed that DES could participate in the conversion process to control the morphology of calcination product.The resultant NiCo_(2)O_(4) nanooctahedrons demonstrated excellent electroactivity and remarkable durability for oxygen evolution reaction(OER).The present strategy not only offers an efficient OER electrocatalyst but also enriches the approaches of DESs in designing advanced nanocatalysts.
文摘In the current work,we are introducing the concept of co-electrolyte in the aqueous medium.Herein,we have prepared the bio-inspired co-electrolyte of choline chloride and potassium hydroxide,which in situ produces choline hydroxide and potassium chloride by the ion-exchange mechanism.The resultant co-electrolyte(RCE)solution exhibits decent electrochemical property than its parental salts,that is,potassium hydroxide,choline chloride.The RCE further used to enhance the energy storage ability of reduced graphene oxide(RGO).The material exhibits maximum specific capacitance 394 F g-1 and higher energy density 44.3 Wh kg-1 at the current density of 1 A g-1 in the presence of co-electrolyte,which is higher as compared to its preceding salts as an electrolyte.Also,the material exhibits lower equivalent series resistance,that is,0.3Ωin RCE.This concept can be considered as future development in the field of energy storage materials.
文摘A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）, and hydrazine hydrate（4） in freshly prepared deep eutectic solvent, DES（choline chloride：urea）. This protocol has afforded corresponding pyrano[2,3-F]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.
