Resumo

BONILLA, S.H.; GIANNETTI, B.F.  e  RABOCZKAY, T.. Chronoamperometric Characterization of the Reduction of the Tin Film Electrogenerated in Sodium Hydrogenocarbonate. Port. Electrochim. Acta [online]. 2004, vol.22, n.3, pp.193-203. ISSN 0872-1904.

The observation of current hysteresis in the cathodic voltammetric profiles of the Sn/bicarbonate electrochemical system motivated chronoamperometric studies, since it is mentioned in literature the correlation between nucleation processes occurrence and current hysteresis presence. The nucleation occurrence was verified by chronoamperometric techniques when films electrogenerated within the passivation region are reduced. Mathematical adjustment between experimental data and calculated according theoretical modelling, was done by employing non-linear least squares fitting routines. This way, the electroreduction of the film formed at lower potentials can be explained in terms of diffusion and progressive nucleation and 3-D growth controlled by charge transfer. On the other hand, the reduction of the film formed at higher potentials follows the model of progressive nucleation and 3-D growth but with the inclusion of induction time. The analysis of the parametric dependence on potential step, enabled to evaluate the role of parallel and normal rate constants for each experimental case.

Palavras-chave : electrochemical reduction; chronoamperometric techniques; tin electrodes.

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