A mathematical model for the radially dependent impedance of a rotating disk electrode

A mathematical model was developed which accounts for the influence of nonu niform current distribution on the impedance response of a rotating disk el ectrode. Results obtained using this two-dimensional model were compared ag ainst those using the one-dimensional model for impedance developed by Trib ollet and Newman. The one-dimensional model was found to be adequate when k inetic limitations cause the current to be uniformly distributed. Significa nt differences between the one-dimensional and two-dimensional models were seen for fast reaction kinetics where the nonuniform ohmic potential distri bution is balanced by a nonuniform concentration overpotential. (C) 1999 Th e Electrochemical Society. An rights reserved.