Multi-frequency analysis in a single square-wave chronoamperometric experiment

Abstract

A multi-frequency analysis in a single SW chronoamperometric protocol is proposed, developed from the recently introduced technique termed as electrochemical faradaic spectroscopy (EFS). In the present multi-frequency electrochemical faradaic spectroscopy (MEFS) the potential modulation consists of SW forward and reverse potential pulses imposed on a constant mid-potential; the frequency of SW pulses increases progressively in the course of the experiment, thus enabling fast and reliable estimation of kinetic parameters in a single experiment. The proposed technique is theoretically analysed with a simple quasireversible electrode reaction of a dissolved redox couple at a planar electrode, as well as with surface confined electrode reaction. Compared with conventional SWV and EFS, MEFS shows advantages in estimation of the standard rate constant in terms of simplicity, speed and efficiency for both studied electrode mechanisms. Theoretical data for surface confined electrode reaction was experimentally tested with azobenzene immobilized on the mercury electrode.

Keywords

• Electrochemical faradaic spectroscopy
• Multi-frequency analysis
• Square wave voltammetry
• Electrode kinetics