Cathodic limiting current

The limiting cathodic current, region 1 in Figure 2.91, corresponds to values of so large that [O]0 [O ]. Hence, the cathodic limiting current, /u, is given by ... 

Anodic and cathodic limiting currents are exhibited because of the rate limiting mass transfer between the electrode and the gas phase. As the potential of the electrode is changed the rate of mass transfer will remain constant and, hence, this behaviour will be manifested as a plateau in the current-overpotential relationship. 

The appearance of a cathodic limiting current after the equivalence point reflects the reduction of excess Ag+ titrant. Figure 3.43B shows resulting amperometric titration curves for two values of applied potential. Their shapes are determined by the behavior of the limiting current of the voltammogram at the particular potential during the titration. 

In Fig. 2.12, the analytical current-time curves under anodic and cathodic limiting current conditions calculated from Eq. (2.137) (Fig. 2.12a and b, respectively) when species R is soluble in the electrolytic solution (solid curves) and when species R is amalgamated in the electrode (dotted lines) are plotted. In Fig. 2.12a, the amalgamation effect on the anodic limiting current has been analyzed. As expected, when species R is soluble in the electrolytic solution, the absolute value of the current density increases when the electrode radius decreases because of the enhancement of... 

The time evolution of the cathodic limiting current (Eq. 2.147) has been plotted in Fig. 2.15 together with that obtained for a planar electrode (Eq. 2.28) and the constant steady-state limiting current for a spherical electrode given by... 

This section considers that the first potential pulse is set at values corresponding to diffusion-controlled cathodic limiting current conditions for the reactant... 

The boundary conditions for this problem, by assuming the application of a constant potential with E Ef (cathodic limiting current see Sect. 2.2.2.1), are... 

The cathodic limiting current equation is, I[ = 0.850 nFAc0 D2q3 v-1 6 v/1)1 2, where A is electrode surface area, m2 Co concentration of oxidized species, molm "3 v kinematic viscosity of solution, m2 s 1 v linear liquid flow speed, ms-1 l = nR/2. 

A similar cathodic limiting current has also been observed for the electroreduction of peroxide on LaNi03 (Fig. 18) [48] and this behavior occurs at potentials where the reduction of the solid surface takes place changing the potential distribution at the oxide-electrolyte interface. This change of surface properties is quite similar to the behavior of NiO [347] under cathodic polarization and is also reflected in the inhibition of electron transfer to or from redox couples in solution [81] and capacitance Mott-Schottky type plots [87, 290, 291] of these interfaces. 

Dependence of the cathodic limiting current density on the angular velocity of the rotating for different alkylaluminum electrolytes (100°C rj = —0.8V) [186, 187]. 

The electrolyte systems El I, II, and III resemble one another and show relatively low cathodic limiting current densities. The cathodic limiting current densities of the various El II electrolytes clearly ascend with increasing value of the 1 2/1 1 complex ratio, as related to electrolyte prehandling. The cathodic limiting current den-... 

Conversion of the 1 2 complex to the 1 1 complex by oxygen or water results also in the production of undesired decomposition products, reducing the specific conductivity, cathodic limiting current density, and throwing power, and thus reducing the coating quality. 

EDA is oxidized rather easily anodically but is resistant to reduction the cathodic limiting current is the discharge of cations or the donation of electrons to the solvent. EDA may be purified by repeated refluxing and distillation from sodium [346]. It is extremely hydroscopic. The TLV is 10 ppm. 

When both members of the redox couple exist in the bulk, we must distinguish between a cathodic limiting current, // c, when Cq x = 0) 0, and an anodic limiting current, // a, when Cr(x = 0) 0. We still have Cq( = 0) given by (1.4.11), but with // now specified as // c- The limiting anodic current naturally reflects the maximum rate at which R can be brought to the electrode surface for conversion to O. It is obtained from (1.4.7) ... 

Utihzing the expression for the cathodic limiting current density as a function of the rotation speed, the Tafel equations take the form ... 

This algebraic equation must involve the anodic limiting current for the reductant and the cathodic limiting current for the oxidant. 

One can also build an equation for the steady-state current-potential curve of a fast system involving only the following three quantities anodic and cathodic limiting currents, /uman 3nd half-wave potential, % The half-wave potential is... 

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