Diffusion–convection impedance using an efficient analytical approximation of the mass transfer function for a rotating disk

• Efficient analytical approximation of the mass transfer function pertaining to RDE.
• Application to the 1-D diffusion–convection impedance for RDE.
• Easy implementation in numerical software for EIS computation/simulation/fitting.

This article mainly focuses on analytical approximation of the mass transfer function for dissolved species reacting at the surface of a uniformly accessible rotating disk electrode. A new analytical expression is proposed for the mass transfer function, with direct application to the associated diffusion–convection impedance. Complex fitting of the impedance model to highly accurate benchmark data is performed to check the efficiency of analytical approximation. Comparison with previous analytical formulations and asymptotic series expansion of the diffusion–convection impedance is also presented.