Oscillographic Chronopotentiometry with High and Low Frequency Current

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.

Investigations on if-E Curve in Cyclic Derivative Chronopotentiometry(Ⅵ)——Theoretical Equations of if-E Curves in the Case of Quasi-reversible and Irreversible Electrode Reactions

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 Simultaneous Determination of Cu Ph Cd and Sb by Derivative Adsorption Chronopotentiometry

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.

The Investigation of Oscillographic Chronopotentiometry at Silver Disk Electrode and Its Mechanism

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).

Investigations on if-E Curve in Cyclic Derivative Chronopotentiometry (Ⅴ)——A Microcomputer-based Data Acquisition System for if-E Curve Measurements

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-

A PRELIMINARY STUDY ON THE THEORY OF THE SECOND AND THIRD ORDER DERIVATIVE ADSORPTION CHRONOPOTENTIOMETRY FOR A REVERSIBLE REACTION

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.

INVESTIGATION ON IMPROVED OSCILLOGRAPHIC CHRONOPOTENTIOMETRY

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.

High Order Harmonic A.C Oscillographic Chronopotentiometry

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.

A Study of Multi-order Semidifferential Oscillographic Chronopotentiometry

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.

Progress in oscillographic chronopotentiometry

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.

Reduction Mechanism of Scandium Ion in Fluoride Salt Melt

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.

Investigation on Feeding Back Current Reciprocal Oscillographic Chronopotentiometric New Techniques

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.

Diffusion Coefficient of Lanthanum in Al-Cu Alloy

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.

ELECTROCHEMICAL DETERMINATION OF CURRENT EFFICIENCY IN ALUMINIUM ELECTROLYSIS

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Continuous preparation of composition-controllable Y-Ni alloy in LiF-YF_(3)-Y_(2)O_(3)molten salt

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.