A novel electroanalytical method. oscillographic chronopotentiometry with high and low frequency current. is presented in this paper. With this method, the sensitivity or almost all kinds of oscillographic chronopoten...A novel electroanalytical method. oscillographic chronopotentiometry with high and low frequency current. is presented in this paper. With this method, the sensitivity or almost all kinds of oscillographic chronopotentiometry can be: enhanced about one order.展开更多
The theory of if-E curve in cyclic derivative chronopotentiometry is presented. Theoretical equations of if-E curves in the case of quasi-reversible and irreversible electrode reactions are deduced respectively.
The behaviour of the complexes of copper,lead,cadmium and antimony with salicylfluorone (SAF) adsorbed on HMDE has been investigated by derivative chronopotentiometry in NH_3/NH_4C1. The dependence of the peak height...The behaviour of the complexes of copper,lead,cadmium and antimony with salicylfluorone (SAF) adsorbed on HMDE has been investigated by derivative chronopotentiometry in NH_3/NH_4C1. The dependence of the peak height on the dt/dE vs E curve on preconcentration time, the pH of solution and the constant reducing current are discussed. This method achieved the simultaneous determination of copper, lead, cadmium and antimony in human hair.展开更多
Theories of the second reciprocal derivative chronopotentiometry analysis were deduced and experimentally verificated.Results in this study show that chronopotentiometry is significantly developed in both sensitivity ...Theories of the second reciprocal derivative chronopotentiometry analysis were deduced and experimentally verificated.Results in this study show that chronopotentiometry is significantly developed in both sensitivity and resolution for signals treated by the second reciprocal derivative.展开更多
A new method of oscillographic chronopotentiometry at silver disk electrode was investigated. By using it, a series of ions such as Pb, In, Cr, Tl, Bi etc. were determined. The detection limits are two or three orders...A new method of oscillographic chronopotentiometry at silver disk electrode was investigated. By using it, a series of ions such as Pb, In, Cr, Tl, Bi etc. were determined. The detection limits are two or three orders of magnitude lower than those by oscillographic chronopotentiometry at mercury electrode. The proposed method is characterized by fine sensitivity, stable oscillogram and no mercury. The research on the mechanism of this method shows that these achievements are caused by the characterristics of silver electroxidation and electroreduction and the oscillographic chronopotentiometry (OC).展开更多
Introduction Quantitative analysis in cyclic derivative chronopotentiometry(CDC) is based on the measurement of the depth of incision on the (dE/dt)～E curve. A serious disadvantage of the method is that a large charg...Introduction Quantitative analysis in cyclic derivative chronopotentiometry(CDC) is based on the measurement of the depth of incision on the (dE/dt)～E curve. A serious disadvantage of the method is that a large charging current obscures the measurement. To improve the sensitivity and the accuracy of CDC, a microcomputer-based data acquisi-展开更多
The equations of the second and third order derivative curves of time with respect to potential for a reversible process in adsorption chronopotentiometry are derived and experimentally verified.
This paper presents a new method called improved oscillographic chronopotcntiometry. It changes the incision of dE/dt-E curve into a peak shape and has the advantages of good reproducibility and wider linear range.
Applying Fourier transform technique to deduction of background and noise on dE/dt-t curve, a new electrochemical method, high order harmonic oscillographic chronopotentiometry is proposed in this paper.
By applying the convolution technique to the treatment of oscillographic signal, a new electroanalytical method, 0.5-3.5 order differential A.C. oscillographic chronopotentiometry is presented. This note represents th...By applying the convolution technique to the treatment of oscillographic signal, a new electroanalytical method, 0.5-3.5 order differential A.C. oscillographic chronopotentiometry is presented. This note represents the experimental circuits, principle and characteristics of the method.展开更多
The investigation on oscillographic chronopotentiometry after 2000 is reviewed. The development course of oscillographic chronopotentiometry is looked back. Some new instrumentations and new methods about oscillograph...The investigation on oscillographic chronopotentiometry after 2000 is reviewed. The development course of oscillographic chronopotentiometry is looked back. Some new instrumentations and new methods about oscillographic chronopotentiometry as well as applications of chemometrics in oscilloanalysis are introduced. The prospects of oscillographic chronopotentiometry development are also discussed in this paper.展开更多
Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb（Ⅱ） and the co-deposition of Pb,Mg and Li on molybdenum electrodes in LiCl-KCl-PbCl2-MgCl2 melts.The diffusion coefficient o...Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb（Ⅱ） and the co-deposition of Pb,Mg and Li on molybdenum electrodes in LiCl-KCl-PbCl2-MgCl2 melts.The diffusion coefficient of lead ions in the melts was determined by different electrochemical techniques.The results obtained by cyclic voltammetry and chronopotentiometry indicated that the underpotential deposition of lithium on pre-deposited Pb leads to the formation of a liquid Li-Pb alloy,and the Mg-Li-Pb alloys are formed after the addition of MgCl2.X-ray diffraction confirmed that in the Mg-Li-Pb alloy,PbLi3,Mg2Pb and Li7Pb2 phases exist by galvanostatic electrolysis at 6.21 A/cm2 for 2 h at 873 K and the phases can be controlled by changing the concentration of PbCl2 and MgCl2.展开更多
The electrochemical behavior of Sc^(3+) in LiF-NaF system was investigated. The cyclic voltammetry and chronopotentiometry were used to investigate the reduction mechanism of the electrochemical deposition of Sc^(3+) ...The electrochemical behavior of Sc^(3+) in LiF-NaF system was investigated. The cyclic voltammetry and chronopotentiometry were used to investigate the reduction mechanism of the electrochemical deposition of Sc^(3+) to Sc on Ag electrode in LiF-NaF system at 1043 K. Experimental results indicate that the electroreduction of Sc^(3+) to Sc is a reversible process with simple 3-electron transfer in one step controlled by diffusion.展开更多
Reciprocal oscillographic chronopotentiogram is such a curve that can converts incisions on "(dE/dt)-E" oscillogram into peaks on "(dt/dE)-E" curve. In order to increase the sensitivity, a new tech...Reciprocal oscillographic chronopotentiogram is such a curve that can converts incisions on "(dE/dt)-E" oscillogram into peaks on "(dt/dE)-E" curve. In order to increase the sensitivity, a new technique called feeding back current was added in new circuit of obtaining reciprocal oscillgraphic chronopotentiogram. It can make capacity current be subtracted easily. Using this method, we carry out studying on principle and titration of drug.展开更多
In molten salt media,the rate of mass transfer process is slower than that of the charge transfer processof an electrochemical reaction.This is attributed to the high temperature which can propagate the rate of thecha...In molten salt media,the rate of mass transfer process is slower than that of the charge transfer processof an electrochemical reaction.This is attributed to the high temperature which can propagate the rate of thecharge transfer process.Being the slowest,the diffusion process is the rate determining step in anelectrochemical reaction.The diffusion coefficient of lanthanum in Al-Cu alloy is determined byelectrochemical method,which will provide very important data for the study of co-deposition of lithiumwith rare earth ions in fused chlorides.展开更多
Electrodialytic （ED） recovery of citric acid （CA） in the presence/absence of strong electrolytes （NaCl, CaCl2 and Feel3） was separately analyzed under different process conditions. Recovery effectiveness was qua...Electrodialytic （ED） recovery of citric acid （CA） in the presence/absence of strong electrolytes （NaCl, CaCl2 and Feel3） was separately analyzed under different process conditions. Recovery effectiveness was quantitatively estimated from current efficiency values. Efficiency attained optimum value with both flow rate and potential applied, while a monotonic rise was noted with temperature which got lowered beyond 0.1 tool. L 1 feed concentration. 40% drop in efficiency was recorded in the presence of strong electrolytes （Noel, CaCl2 and Feel3） in feed relative to their presence in concentrate. Severe transport hindrance and efficiency loss were attributed to adsorption and allied physicochemical changes occurred with anion/cation exchange membranes （AEM/CEM） and these were confirmed through contact angle/Chronopotentiometry/AFM/EDX. Sluggish potential rise （Galvanostatic mode） in Chronopotentiometric analysis indicated diffusion limiting transport of organic acids influenced AEM resistance. XRD and EDX analysis indicated the presence of salt hydrates/ions （Ca2＋/Fe3＋） over CEM justifying the resistance buildup due to adsorption of multivalent metal ion（s） and salts.展开更多
The Y-Ni alloy is a primary precursor for the preparation of high-performance La-Y-Ni-based hydrogen storage materials.However,it cannot be produced continuously at low cost,which limits the wide popularization and ap...The Y-Ni alloy is a primary precursor for the preparation of high-performance La-Y-Ni-based hydrogen storage materials.However,it cannot be produced continuously at low cost,which limits the wide popularization and application of La-Y-Ni-based materials.In this paper,this problem was solved perfectly using electrochemical reduction of Y_ (2)O_(3)in the LiF-YF_(3)system.It is found that the reversible reduction from Y^(3+)to Y on the W electrode takes only one step,namely a significant soluble-soluble reaction controlled by Y^(3+)diffusion throughout the melt.Four typical signals of square wave voltammetry(SWV)corresponding to different kinds of Y-Ni intermetallic compounds are observed in LiF-YF_(3)and LiF-YF_(3)-Y_ (2)O_(3)melts,and reduction potential can become positive with the addition of Y_ (2)O_(3),probably because of the formation of more complexes in the melts.Homogeneous Y-Ni alloy samples were produced continuously and prepared via galvanostatic electrolysis by using bargain-price raw material(Y_ (2)O_(3))and setting the current density at 10 A/cm^(2)on the nickel electrode,before they were collected into a bottom receiver.A series of analyses including scanning electron microscopy-energy idspersive X-ray spectroscopy(SEM-EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and inductively coupled plasma mass spectrometry(ICP-MS),demonstrate that concentration of yttrium in Y-Ni alloy is adjustable within the wide range of 44 wt%to 72 wt%by fine-tuning the electrolysis temperature(875-1060℃)in the LiF-YF_(3)system to ensure the optimal hydrogen storage performance and economic efficiency of La-Y-Ni-based hydrogen-storage materials.展开更多
基金The authors gratefully acknowedge the financial support from the National Natural Scicllcc Foundation of China Nat
文摘A novel electroanalytical method. oscillographic chronopotentiometry with high and low frequency current. is presented in this paper. With this method, the sensitivity or almost all kinds of oscillographic chronopotentiometry can be: enhanced about one order.
基金Supported by the National Natural Science Foundation of China
文摘The theory of if-E curve in cyclic derivative chronopotentiometry is presented. Theoretical equations of if-E curves in the case of quasi-reversible and irreversible electrode reactions are deduced respectively.
基金Project is supported by Natural Science Foundation of Shandong Province
文摘The behaviour of the complexes of copper,lead,cadmium and antimony with salicylfluorone (SAF) adsorbed on HMDE has been investigated by derivative chronopotentiometry in NH_3/NH_4C1. The dependence of the peak height on the dt/dE vs E curve on preconcentration time, the pH of solution and the constant reducing current are discussed. This method achieved the simultaneous determination of copper, lead, cadmium and antimony in human hair.
基金Project supported by the Natural Science Foundation of the Education Committee of Hunan Province.
文摘Theories of the second reciprocal derivative chronopotentiometry analysis were deduced and experimentally verificated.Results in this study show that chronopotentiometry is significantly developed in both sensitivity and resolution for signals treated by the second reciprocal derivative.
文摘A new method of oscillographic chronopotentiometry at silver disk electrode was investigated. By using it, a series of ions such as Pb, In, Cr, Tl, Bi etc. were determined. The detection limits are two or three orders of magnitude lower than those by oscillographic chronopotentiometry at mercury electrode. The proposed method is characterized by fine sensitivity, stable oscillogram and no mercury. The research on the mechanism of this method shows that these achievements are caused by the characterristics of silver electroxidation and electroreduction and the oscillographic chronopotentiometry (OC).
基金Supported by the National Natural Science Foundation of China
文摘Introduction Quantitative analysis in cyclic derivative chronopotentiometry(CDC) is based on the measurement of the depth of incision on the (dE/dt)～E curve. A serious disadvantage of the method is that a large charging current obscures the measurement. To improve the sensitivity and the accuracy of CDC, a microcomputer-based data acquisi-
文摘The equations of the second and third order derivative curves of time with respect to potential for a reversible process in adsorption chronopotentiometry are derived and experimentally verified.
文摘This paper presents a new method called improved oscillographic chronopotcntiometry. It changes the incision of dE/dt-E curve into a peak shape and has the advantages of good reproducibility and wider linear range.
文摘Applying Fourier transform technique to deduction of background and noise on dE/dt-t curve, a new electrochemical method, high order harmonic oscillographic chronopotentiometry is proposed in this paper.
文摘By applying the convolution technique to the treatment of oscillographic signal, a new electroanalytical method, 0.5-3.5 order differential A.C. oscillographic chronopotentiometry is presented. This note represents the experimental circuits, principle and characteristics of the method.
基金supported by the National Natural Science Foundation of China(Grant No.20275030)the Natural Science Foundation of Shaanxi Province in China(No.2004B20).
文摘The investigation on oscillographic chronopotentiometry after 2000 is reviewed. The development course of oscillographic chronopotentiometry is looked back. Some new instrumentations and new methods about oscillographic chronopotentiometry as well as applications of chemometrics in oscilloanalysis are introduced. The prospects of oscillographic chronopotentiometry development are also discussed in this paper.
基金Projects(50871033,21173060,21103033) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(2011AA03A409,2009AA050702,2007CB200906) supported by the Basic Research Foundation of Harbin Engineering University,China
文摘Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb（Ⅱ） and the co-deposition of Pb,Mg and Li on molybdenum electrodes in LiCl-KCl-PbCl2-MgCl2 melts.The diffusion coefficient of lead ions in the melts was determined by different electrochemical techniques.The results obtained by cyclic voltammetry and chronopotentiometry indicated that the underpotential deposition of lithium on pre-deposited Pb leads to the formation of a liquid Li-Pb alloy,and the Mg-Li-Pb alloys are formed after the addition of MgCl2.X-ray diffraction confirmed that in the Mg-Li-Pb alloy,PbLi3,Mg2Pb and Li7Pb2 phases exist by galvanostatic electrolysis at 6.21 A/cm2 for 2 h at 873 K and the phases can be controlled by changing the concentration of PbCl2 and MgCl2.
文摘The electrochemical behavior of Sc^(3+) in LiF-NaF system was investigated. The cyclic voltammetry and chronopotentiometry were used to investigate the reduction mechanism of the electrochemical deposition of Sc^(3+) to Sc on Ag electrode in LiF-NaF system at 1043 K. Experimental results indicate that the electroreduction of Sc^(3+) to Sc is a reversible process with simple 3-electron transfer in one step controlled by diffusion.
文摘Reciprocal oscillographic chronopotentiogram is such a curve that can converts incisions on "(dE/dt)-E" oscillogram into peaks on "(dt/dE)-E" curve. In order to increase the sensitivity, a new technique called feeding back current was added in new circuit of obtaining reciprocal oscillgraphic chronopotentiogram. It can make capacity current be subtracted easily. Using this method, we carry out studying on principle and titration of drug.
文摘In molten salt media,the rate of mass transfer process is slower than that of the charge transfer processof an electrochemical reaction.This is attributed to the high temperature which can propagate the rate of thecharge transfer process.Being the slowest,the diffusion process is the rate determining step in anelectrochemical reaction.The diffusion coefficient of lanthanum in Al-Cu alloy is determined byelectrochemical method,which will provide very important data for the study of co-deposition of lithiumwith rare earth ions in fused chlorides.
基金Financial support to execute the experimental work is gratefully acknowledged to IIT Roorkee(No.IITR/SRIC/244/FIG-Sch-A)UAY Project(ICSR/UAY/2016/SN dt 04/01/2017),India
文摘Electrodialytic （ED） recovery of citric acid （CA） in the presence/absence of strong electrolytes （NaCl, CaCl2 and Feel3） was separately analyzed under different process conditions. Recovery effectiveness was quantitatively estimated from current efficiency values. Efficiency attained optimum value with both flow rate and potential applied, while a monotonic rise was noted with temperature which got lowered beyond 0.1 tool. L 1 feed concentration. 40% drop in efficiency was recorded in the presence of strong electrolytes （Noel, CaCl2 and Feel3） in feed relative to their presence in concentrate. Severe transport hindrance and efficiency loss were attributed to adsorption and allied physicochemical changes occurred with anion/cation exchange membranes （AEM/CEM） and these were confirmed through contact angle/Chronopotentiometry/AFM/EDX. Sluggish potential rise （Galvanostatic mode） in Chronopotentiometric analysis indicated diffusion limiting transport of organic acids influenced AEM resistance. XRD and EDX analysis indicated the presence of salt hydrates/ions （Ca2＋/Fe3＋） over CEM justifying the resistance buildup due to adsorption of multivalent metal ion（s） and salts.
基金Project supported by the State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization(2020Z2132)Ganjiang Innovation Academy,Chinese Academy of Sciences(E055C002)。
文摘The Y-Ni alloy is a primary precursor for the preparation of high-performance La-Y-Ni-based hydrogen storage materials.However,it cannot be produced continuously at low cost,which limits the wide popularization and application of La-Y-Ni-based materials.In this paper,this problem was solved perfectly using electrochemical reduction of Y_ (2)O_(3)in the LiF-YF_(3)system.It is found that the reversible reduction from Y^(3+)to Y on the W electrode takes only one step,namely a significant soluble-soluble reaction controlled by Y^(3+)diffusion throughout the melt.Four typical signals of square wave voltammetry(SWV)corresponding to different kinds of Y-Ni intermetallic compounds are observed in LiF-YF_(3)and LiF-YF_(3)-Y_ (2)O_(3)melts,and reduction potential can become positive with the addition of Y_ (2)O_(3),probably because of the formation of more complexes in the melts.Homogeneous Y-Ni alloy samples were produced continuously and prepared via galvanostatic electrolysis by using bargain-price raw material(Y_ (2)O_(3))and setting the current density at 10 A/cm^(2)on the nickel electrode,before they were collected into a bottom receiver.A series of analyses including scanning electron microscopy-energy idspersive X-ray spectroscopy(SEM-EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and inductively coupled plasma mass spectrometry(ICP-MS),demonstrate that concentration of yttrium in Y-Ni alloy is adjustable within the wide range of 44 wt%to 72 wt%by fine-tuning the electrolysis temperature(875-1060℃)in the LiF-YF_(3)system to ensure the optimal hydrogen storage performance and economic efficiency of La-Y-Ni-based hydrogen-storage materials.
