Double potential step chronoamperometry at a microband electrode: Theory and experiment

TL;DR

This study combines numerical simulation and experimental validation to demonstrate that double potential step chronoamperometry at a microband electrode effectively measures diffusion coefficients of redox species, with high sensitivity and accuracy.

Contribution

It provides a validated theoretical and experimental framework for using double potential step chronoamperometry to accurately determine diffusion coefficients at microband electrodes.

Findings

Excellent agreement between theory and experiment.

Measured diffusion coefficients for DMFc and DMFc+ at 298 K.

Method shows high sensitivity for diffusion coefficient measurement.

Abstract

Numerical simulation is used to characterise double potential step chronoamperometry at a microband electrode for a simple redox process A + e- goes to B, under conditions of full support such that diffusion is the only active form of mass transport. The method is shown to be highly sensitive for the measurement of the diffusion coefficient of both A and B, and is applied to the one electron reduction of decamethylferrocene (DMFc), DMFc - e- goes to DMFc+, in the room temperature ionic liquid 1-propyl-3-methylimidazolium bistrifluoromethylsulfonylimide. Theory and experiment are seen to be in excellent agreement and the following values of the diffusion coefficients were measured at 298 K: D_(DMFc) = 2.50 x 10^(-7) cm^(2) s^(-1) and D_(DMFc+) = 9.50 x 10^(-8) cm^(2) s^(-1).