Abstract:

For an irreversible consecutive charge-transfer reaction with an adsorbed intermediate species. its faradaic impedance usually displays a low frequency inductive are in the complex plane at the lower overpotentials. Moreover, the inductive are will transform into a capacitive one at the higher overpotentials, which implies a change of the rate-determining step for this reaction. On the contrary the faradaic relaxation at low frequency shows the capacitive behavior provided the rate of reaction is controlled by one step all along the reaction.

Key words: Adsorbed intermediate species, The faradaic relaxation, Electrochemical Impedance Spectroscopy(ElS)