Analysis of the cyclic voltammetric responses exhibited by electrodes modified with monolayers of catalysts in the absence and presence of substrates

Abstract

Abstract The cyclic voltammetric responses to be expected from electrodes to which monolayers of redox catalysts are attached are calculated in the absence and presence of substrates for the catalyst. The consequences of interactions among the attached catalyst molecules and/or finite rates of the electrode reaction are treated explicitly. Relationships among peak currents, peak and half-peak potentials of the pure catalytic waves and the rate constant for the catalytic reaction are derived, from which the rate constant of the catalytic reaction can be evaluated. When the rate of the electrode reaction for the catalyst is high, the pure catalytic component of the observed voltammetric responses can be obtained by subtraction of the response from the catalyst in the absence of substrate from the observed response in the presence of substrate. However, this convenient property is lost as the rate constant of the electrode reaction decreases. A kinetic parameter was found empirically from which the experimental conditions required to allow the simple subtraction procedure to be used reliably even in the presence of slow electron transfer were established.