General analytical solution for a catalytic mechanism in potential step techniques at hemispherical microelectrodes: Applications to chronoamperometry, cyclic staircase voltammetry and cyclic linear sweep voltammetry

摘要

An easy, general analytical solution, applicable to any multipotential step technique for a catalytic process in planar and spherical electrodes (including ultramicrohemispheres), is presented. The solution has been deduced rigorously using the mathematical method described by Molina (A. Molina, J. Electroanal. Chem. 443 (1998) 163) based on the application of the superposition principle. In this paper it has been applied to multistep chronoamperometry, cyclic staircase voltammetry (CSCV) and cyclic linear sweep voltammetry (CLSV) by analysing the influence of the electrode radius and the equilibrium and rate chemical constants over the different I/t and I/E responses. Different voltammetric steady states (kinetic, microgeometrical and geometrical-kinetic) can be distinguished and methods for calculating the kinetic parameters of the chemical reaction are also proposed. In the case of an irreversible chemical reaction in linear sweep voltammetry our results are in agreement with those recently deduced by Diao and Zhang (G. Diao, Z. Zhang, J. Electroanal. Chem. 429 (1997) 67).