The problem of the accuracy of electrochemical kinetic parameter determination for the ECE reaction mechanism

The theoretical and practical possibilities of the determination of elementary kinetic parameters k1, α1, k2, α2 for sequence A→k1,α1B→kfC→k2,α2D were examined for various k2/k1 ratios on the basis of electrochemical simulations. The errors of the kinetic parameters evaluated from theoretical CV curves or from those with artificial noise added were calculated and discussed. The subject is important for the modelling of the ECE mechanism and other consecutive reaction steps. The work demonstrates quantitatively the relations that are qualitatively familiar to chemists: a precise determination of second stage kinetic parameters in a consecutive process is impossible if their magnitude is much higher than that in the first stage.