The Rotating Disk Electrode. Effect if Rates of Rotation and Polarization.

Abstract

The rotating disk electrode has been used to investigate the transition between the peak current and the limiting current regions in terms of the chief mode of mass transport which controls the electrode process. The oxidation of ferrocyanide in chloride solution on wax-impregnated graphite was the experimental system used. Experiments at slow rotation speeds and fairly fast polarization rates show current peaks rather than plateaus, indicating that the main mode of mass transport of the electroactive species to the electrode surface is determined not only by whether the electrode is rotated or not, but also by the relative magnitudes of the speed of rotation and of the rate of polarization.Theoretical explanation of this phenomenon is given. HE ORIGINAL PURPOSE of using

On the Behavior of the Porous Rotating Disk Electrode

“…It is when convection becomes comparable to or dominates diffusion that the Levich equation holds. Here we note that the two regimes of reactant transport we identified in our analytic models of the PRDE, advection dominant and diffusion dominant each correspond to the 'convection dominant' and 'comparable convection and diffusion' regimes of Fried and Elving's (1965) study of the RDE.…”

“…These current peaks appearing instead of plateaus at low rotation rates are also called non-steady-state diffusional peaks and have been observed in RDE experiments at higher scan rates and lower rotation rates. The relation between these two rates and the current has been studied and discussed by Fried & Elving (1965). As the rotation rate increases, it is possible to use higher scan rates and still obtain the steady state plateaus.…”

Reaction Mechanism for Oxygen Reduction on Platinum: Existence of a Fast Initial Chemical Step and a Soluble Species Different from H2O2

“…Under such a condition, j-E profiles for single electrochemical reactions at both, stationary and rotating disk electrodes, should have a current peak, j p , proportional to √v, Eqn. 5, and independent of ω in the case of RDEs [56][57][58][59][60][61][62]87] (10, -10) This result, however, does not imply that the amount of adsorbed O-containing species during the ORR would be the same as in O 2 -free solutions, and it could be higher, as indicated by X-ray photoelectron spectroscopy (XPS) [11], electrochemical quartz crystal microbalance (EQCM) measurements [14,78], and studies at microelectrodes [54,55]. ோ் at a smaller slope than the one expected for a 1etransfer, and later become independent of v. This transition depends on ω and takes place at 0.5 and 10…”

“…Typical kinetic analysis of steady-state curves at different ω, Figure 4, In contrast, when v is large relative to ω, the time of the experiment is short and diffusion predominates over convection, δ diff << δ ω [56][57][58][59][60][61][62]87]. Under such a condition, j-E profiles for single electrochemical reactions at both, stationary and rotating disk electrodes, should have a current peak, j p , proportional to √v, Eqn.…”

The role of chemisorbed hydroxyl species in alkaline electrocatalysis of glycerol on gold

“…This effect has been frequently observed in previous CV studies of RDE systems, 65,66 and its origin has been explained in terms of a competition between the speed of voltage scan and that of disc rotation under quasi-steady state conditions. 19,67,68 The underlying mechanism of this effect is briefly noted below.…”