Determination of kinetic parameters of Fe3+ reduction mediated by a polyaniline film using steady-state and impedance methods.

The Fe 3+ reduction reaction was studied at Pt and polyaniline rotating disk electrodes by steady-state and impedance methods with the aim of testing the possibility of achieving the charge transfer resistance (Rts) of a redox reaction mediated by a conducting polymer film by ac impedance. Rt~ was obtained as a function of electrode potential and rotation rate by nonlinear least squares fitting of a previously developed kinetic equation to the experimental data. These Rts values were combined with steady-state ones to calculate bc and k°.