Polarographic studies in aqueous melts: Half-wave potentials, diffusion coefficients and related measurements

1972 ◽  
Vol 37 (11) ◽  
pp. 3697-3705 ◽  
Author(s):  
D. G. Lovering
Keyword(s):  
Diffusion Coefficients ◽  
Half Wave

Some thermodynamic and kinetic properties of H2SO4–H3PO4–H2O–Fe(III) system

2021 ◽  
pp. 1-9
Author(s):  
Ya.G. Avdeev ◽  
Keyword(s):  
Diffusion Coefficients ◽  
Arrhenius Equation ◽  
Platinum Electrode ◽  
Molar Fraction ◽  
Redox Couple ◽  
Kinetic Properties ◽  
Cyclic Voltammogram ◽  
Electrode Potentials ◽  
Half Wave ◽  
Sulfate Complexes

The values of the electrode potentials of the redox couple Fe(III) / Fe(II) and the half-wave potentials of the reactions Fe3+ + e– = Fe2+ и Fe2+ — e– = Fe3+ on the cyclic voltammogram of a platinum electrode in acid solutions containing Fe(III) salts have been measured to characterize the oxidizing ability of the H2SO4—H3PO4—H2O—Fe(III) system. The values of these experimentally obtained parameters are close. A decrease in the oxidizing ability of H2SO4 and H3PO4 mixtures containing Fe(III) with an increase in the molar fraction of H3PO4 in them occurs due to the formation of Fe(III) complexes with phosphate anions which are inferior to their hydrate and sulfate complexes in the oxidizing ability. The temperature coefficients of the electrode potential (dE / dt) of the redox couple Fe(III) / Fe(II) in the H2SO4—H2O, H2SO4—H3PO4—H2O and H3PO4–H2O systems were determined experimentally. The diffusion coefficients of Fe(III) in the studied solutions were calculated based on the Randles—Shevchik equation. The temperature dependence of the diffusion coefficients of Fe(III) cations is satisfactorily described by the Arrhenius equation. The parameters of this equation are calculated.

scholarly journals Calculation of Electrochemical Parameters Starting from the Polarization Curves of Ferrocene at Glassy Carbon Electrode

2013 ◽  
Vol 9 ◽  
pp. 37-45 ◽  
Author(s):  
N.S. Neghmouche ◽  
Touhami Lanez
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Diffusion Coefficients ◽  
Polarization Curves ◽  
Carbon Electrode ◽  
Half Wave ◽  
Electrochemical Parameters

This work is a contribution to the calculation of electrochemical parameters from the polarization curves of ferrocene. The parameters are: The anodic (Epa) and the cathodic (Epc) peak potentials, as well as the corresponding anodic (ipa) and cathodic (ipc) peak currents, were obtained at different scan rates (0.05, 0.10, 0.30, 0.50 V.s-1). The half-wave potentials (E1/2) of the couple in the investigated solvents have been evaluated. The diffusion coefficients (D) have been calculated using the Randles-Sevcik equation.

POLAROGRAPHIC DETERMINATION OF THE DISSOCIATION CONSTANT OF THE SULPHYDRYL GROUP AND DIFFUSION COEFFICIENT MEASUREMENTS OF THIOMALIC ACID

1961 ◽  
Vol 39 (11) ◽  
pp. 2236-2239 ◽  
Author(s):  
R. C. Kapoor ◽  
O. P. Agrawal ◽  
T. D. Seth
Keyword(s):  
Diffusion Coefficients ◽  
Polarographic Study ◽  
Standard Potential ◽  
Charged Species ◽  
Half Wave ◽  
Ph Range ◽  
And Diffusion ◽  
Respective Species ◽  
Made In

Polarographic study of thiomalic acid has been made in the pH range 1–12.5 using Britton–Robinson buffer at 30°. The half-wave potential [Formula: see text] values have been used to determine the pK3 (SH) value of the acid (pK3 = 10.55).The diffusion current obtained in these experiments has been utilized to calculate the diffusion coefficients of the different charged species of thiomalic acid. The values thus obtained for the respective species are H3A = 1.20 × 10−5 cm2/sec; H2A− = 1.16 × 10−5 cm2/sec; HA−− = 1.08 × 10−5 cm2/sec; and A−−− = 7.67 × 10−6 cm2/sec.The standard potential of the reaction[Formula: see text]has been calculated as +0.266 volt vs. N.H.E.

Interlayer mixing in GaAs/AlxGa1-xAs heterostructures as a result of Se+ ion implantation

1988 ◽  
Vol 46 ◽  
pp. 908-909
Author(s):  
E.G. Bithell ◽  
W.M. Stobbs
Keyword(s):  
Ion Implantation ◽  
Diffusion Coefficients ◽  
Dark Field ◽  
Atomic Mass ◽  
Composition Profile ◽  
Semiconductor Heterostructures ◽  
Transmission Electron ◽  
Microscope Images ◽  
Damage Process ◽  
Electron Energy Loss

It is well known that the microstructural consequences of the ion implantation of semiconductor heterostructures can be severe: amorphisation of the damaged region is possible, and layer intermixing can result both from the original damage process and from the enhancement of the diffusion coefficients for the constituents of the original composition profile. A very large number of variables are involved (the atomic mass of the target, the mass and energy of the implant species, the flux and the total dose, the substrate temperature etc.) so that experimental data are needed despite the existence of relatively well developed models for the implantation process. A major difficulty is that conventional techniques (e.g. electron energy loss spectroscopy) have inadequate resolution for the quantification of any changes in the composition profile of fine scale multilayers. However we have demonstrated that the measurement of 002 dark field intensities in transmission electron microscope images of GaAs / AlxGa1_xAs heterostructures can allow the measurement of the local Al / Ga ratio.

Sign in / Sign up

Export Citation Format

Share Document