Charge neutralization process of mobile species developed during potentiodynamic conditions. Part 1: Theory

F. GARAY; C.A. BARBERO

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

elsevier

Lugar: amsterdam; Año: 2008 vol. 624 p. 218 - 227

0022-0728

The theoretical model presented in Part 1 is employed to simulate and fit experimental probe beamdeflection (PBD) data of FeðCNÞ3 6 =FeðCNÞ4 6 and Fe3+/Fe2+ couples collected under voltammetric conditions.The dependence of beam deviation on the diffusion coefficients and on the charges of involved speciesis described. The fit of voltammetric curves was performed to get the values for the standardpotential of each system as well as diffusion coefficients of electroactive species. The data were thenemployed to fit a set of experimental voltadeflectometric profiles collected at different beam-electrodedistances. The least-squares Simplex algorithm was employed to fit proposed functions to experimentaldata. The data obtained from the fitted voltadeflectometric curves were consistent with values previouslyreported for chronodeflectometry profiles, supporting the hypothesis that the refraction index not onlyshould be considered a function of the concentration of the neutral salts dissolved, but also dependson the concentration gradient of each soluble species. The effects of the scan rate and the beam-electrodedistance are discussed in detail. In relation to this, simple relationships between these adjustable parametersand the angle of the deflected laser beam are also provided. Thus, it is now possible to perform aquantitative analysis on the response of techniques such as PBD when the heterogeneous charge transferof electroactive species is studied with a cyclic linear potential scan.