The electrocatalytic activity of Prussian blue in hydrogen peroxide reduction studied using a wall-jet electrode with continuous flow

Abstract

The kinetics of hydrogen peroxide reduction on electrodes modified with specially deposited Prussian blue were investigated using a wall-jet cell with continuous flow. For this aim a new semi-empirical model for the diffusion limited current distribution holding for narrow wall-jet electrodes was described. In spite of the non-uniform accessibility of the wall-jet electrode surface in terms of mass transport the evaluated equation for the total current density (j) allowed the separation of the diffusion and kinetic terms of the current through investigating the dependence of j on the volume flow rate (V) in (1/j vs V−3/4) plots. The theoretical conclusions presented were confirmed by kinetic investigations of the electrocatalytic reduction of H2O2 at glassy carbon wall-jet electrodes modified with Prussian blue. The bimolecular rate constant for the reduction of H2O2 on the specially deposited Prussian blue was found to be kcat=3×103 M−1 s−1. Due to the characteristics of the high catalytic activity and selectivity, which were comparable with biocatalysis using peroxidase, the Prussian blue based electrocatalyst is denoted as ‘artificial peroxidase’.