A Mathematical Model for the Radially Dependent Impedance of a Rotating Disk Electrode

Abstract

A mathematical model was developed which accounts for the influence of nonuniform current distribution on the impedance response of a rotating disk electrode. Results obtained using this two-dimensional model were compared against those using the one-dimensional model for impedance developed by Tribollet and Newman. The one-dimensional model was found to be adequate when kinetic limitations cause the current to be uniformly distributed. Significant differences between the one-dimensional and two-dimensional models were seen for fast reaction kinetics where the nonuniform ohmic potential distribution is balanced by a nonuniform concentration overpotential.

Power law for frequency-dependence of double layer capacitance of graphene flakes

“…Thicker carbon films obviously enhance the capacitance. They also increase frequency-dependence of their capacitors [1,2], because the dependence is generally exhibited more strongly at electrodes with surface roughness of fractal dimension [3][4][5][6][7][8][9][10], with high porosity [11][12][13], heterogeneous distributions of current density [14][15][16][17], inhomogeneous adsorption [18], and inhomogeneous coating materials [19,20]. The common reason for the frequency dependence is heterogeneity of electrodes.…”

A systematic approach toward error structure identification for impedance spectroscopy

“…The error analysis approach was used to facilitate development of interpretation models for PANI free-standing polyaniline membranes [3] and to establish a model for interpreting impedance data for corrosion of cast iron in drinking water [4]. The error analysis was combined with development of mathematical models [5] to demonstrate the influence of current distribution and poisoning on the impedance response associated with the reduction of ferricyanide on a platinum rotating disk electrode [6]. The error analysis facilitated discrimination among mathematical models for convective diffusion to a disk electrode under a submerged impinging jet for corrosion of steel in brines containing CO 2 [7].…”

Re-examination of the diffusion–convection impedance for a uniformly accessible rotating disk. Computation and accuracy

“…Durbha et al [26] presented the mathematical formalism for frequencydomain techniques. From the theoretical predictions in Refs.…”

“…From the theoretical predictions in Refs. [22][23][24][25][26], it is known that current distribution on the electrode surface is highly uniform in the case of low Ohmic drop and slow electron-transfer kinetics. The present article focuses on such conditions and, therefore, on 1-D diffusion-convection processes.…”