Theory of square-wave catalytic adsorptive stripping voltammetry. How to obtain mechanistic information from experimental data

VETTORELO, SABRINA N.; GARAY, FERNANDO

JOURNAL OF ELECTROANALYTICAL CHEMISTRY - (Print)

ELSEVIER SCIENCE SA

Año: 2018 vol. 826 p. 125 - 132

1572-6657

The sensitivity of a catalytic adsorptive stripping voltammetric method depends mainly on the strength of adsorption of the electroactive reactant and the efficiency of the catalytic reaction. While the strength of adsorption is associated with the type of reagent and the solution pH, the efficiency of the catalytic step depends on the type and concentration of the oxidant selected for such reaction. Although the probe-and-error approach is commonly used for optimizing a given analytical signal, information about the reaction scheme and some good estimation about the rate constants of involved reactions would help a lot to optimize the analytical system. The possibility for using the quasi-reversible maximum to study the electrode kinetics depends on the values of kcat, Kad, f, Esw, and of course ks. As a result of this, it is rather difficult for experimentalist and also for theoreticians to organize a strategy for detecting and understanding the effect of each variable separately. In this manuscript, it is first shown the effect of different variables on the voltammetric response, and then it is suggested a strategy for studying and estimating the values of those variables. Thus, if the experimental system matches the reaction scheme of an electrochemical reaction complicated by following homogeneous catalytic reaction, then it is advisable to follow a set of simple experimental steps to characterize the kinetic constants of the system.