The theory of steady state current for chronoamperometric and cyclic voltammetry on rotating disk electrodes for EC’ and ECE reactions

2019 ◽  
Vol 313 ◽  
pp. 441-456 ◽  
Author(s):  
R. Saravanakumar ◽  
P. Pirabaharan ◽  
L. Rajendran
Keyword(s):  
Cyclic Voltammetry ◽  
Steady State ◽  
Rotating Disk ◽  
Steady State Current ◽  
Disk Electrodes

scholarly journals Transient Current Density in a Pair of Long Parallel Conductors

2021 ◽  
Vol 11 (15) ◽  
pp. 6920
Author(s):  
Oldřich Coufal
Keyword(s):  
Steady State ◽  
Cross Section ◽  
Current Density ◽  
Circular Cross Section ◽  
Transient Current ◽  
Constant Current ◽  
Voltage Source ◽  
Sinusoidal Voltage ◽  
Steady State Current ◽  
Maximum Current

Two infinitely long parallel conductors of arbitrary cross section connected to a voltage source form a loop. If the source voltage depends on time, then due to induction there is no constant current density in the loop conductors. It is only recently that a method has been published for accurately calculating current density in a group of long parallel conductors. The method has thus far been applied to the calculation of steady-state current density in a loop connected to a sinusoidal voltage source. In the present article, the method is used for an accurate calculation of transient current using transient current density. The transient current is analysed when connecting and short-circuiting the sources of sinusoidal, constant and sawtooth voltages. For circular cross section conductors, the dependences of maximum current density, maximum current and the time of achieving steady state on the source frequency, the distance of the conductors and their resistivity when connecting the source of sinusoidal voltage are examined.

Mineral interfacial processes in the method of induced polarization

Geophysics ◽  
1984 ◽  
Vol 49 (7) ◽  
pp. 1105-1114 ◽  
Author(s):  
James D. Klein ◽  
Tom Biegler ◽  
M.D. Horne
Keyword(s):  
Frequency Domain ◽  
Diffusion Layer ◽  
Electrode Potential ◽  
Rotation Speed ◽  
Low Frequency ◽  
Rotating Disk ◽  
Active Species ◽  
Hydrodynamic Theory ◽  
Electrode Polarization ◽  
Disk Electrodes

A phenomenological laboratory investigation has been conducted of the IP response of pyrite, chalcopyrite, and chalcocite. The technique that was used is standard in electrochemistry and employs rotating disk electrodes. The effect of rotation is to stir the electrolyte and thus to restrict the maximum distance available for diffusion of electroactive aqueous species. For high rotation speed and low excitation frequencies, the mean diffusion length exceeds the thickness of the diffusion layer. The net effect is to reduce the electrode impedance at low frequency. The thickness of the diffusion layer and thus the impedance at low frequency can be controlled by the rotation speed. Measurements using rotating disk electrodes have been conducted in both the time domain and the frequency domain. For both pyrite and chalcopyrite, the results were the same: no dependence on rotation was observed. For frequency domain measurements with chalcocite, a strong dependence on rotation was observed. The interpreted diffusion layer thickness was found to depend on rotation speed to the [Formula: see text] power, in agreement with results predicted by hydrodynamic theory. The results of this study imply that there are two physical processes responsible for electrode polarization in the IP method. For chalcocite and perhaps other related copper sulfide minerals, the probable mechanism is diffusion of copper ions in the groundwater. In case, the phenomenon is correctly described by the Warburg impedance. Chalcocite’s distinctive response is thought to be related to its forming a reversible oxidation‐reduction couple with cupric ions in solution. No other common sulfide mineral forms a reversible couple with its cations in solution. For the other minerals of this study, the lack of dependence on rotation implies that diffusion of active species in the electrolyte is not the controlling process. Possible alternate mechanisms include surface controlled processes such as surface diffusion or adsorption phenomena. Ancillary data obtained during this study indicate the interface impedance of chalcopyrite is proportional to the electrode potential which in turn can be controlled by rotation speed, electrolyte composition, or application of an external dc current or voltage. This implies that the surface concentration of active species is dependent on electrode potential.

scholarly journals Redox mediation at poly(o-aminophenol) coated electrodes: Mechanistic diagnosis from steady state polarization curves

2018 ◽  
Author(s):  
Gabriel Ybarra ◽  
Carlos Moina ◽  
María Inés Florit ◽  
Dionisio Posadas
Keyword(s):  
Steady State ◽  
Polarization Curve ◽  
Experimental Measurements ◽  
Steady State Current ◽  
Thermodynamical Parameters ◽  
Reduction And Oxidation ◽  
Mediated Reduction ◽  
Coated Electrodes ◽  
Current Potential ◽  
Potential Curves

<p class="PaperAbstract"><span lang="EN-US">In this work, the mediated reduction and oxidation of Fe(CN)<sub>6</sub><sup>3-/4-</sup> and Fe<sup>3+ </sup>in poly(o-aminophenol) coated electrodes is analyzed by means of diagnosis diagram based on the features of steady state current-potential curves. This analysis allows to identify the current determining process and to reproduce the experimental characteristics of the polarization curve from the relevant kinetic and thermodynamical parameters with a minimum amount of experimental measurements. </span></p>

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