The pathways towards the steady state E/t and I/E responses when using an alternating current

Equations corresponding to the application of an alternating current to spherical electrodes, including as limit cases planar electrodes and spherical microelectrodes have been deduced. We have also analyzed the evolution from transient to stationary potential–time and current–potential responses. This technique is particularly interesting when the reduction transition time does not exist since, when only the oxidized species is initially present, the reoxidation transition time for a transfer charge reaction under steady state conditions is only dependent on the frequency of the alternating current applied and, therefore, it is possible to detect any kinetic complication relating to the behaviour of the reduced species. We also propose methods for the accurate determination of thermodynamic and kinetic parameters of the charge transfer process from the analysis of the broad central zone of transient and stationary E/t and I/E curves, a region which is barely affected by capacitative distortion. The validity of the theoretical predictions has been experimentally tested with different reversible and irreversible systems.