Diffusion, reaction and forced convection in electrochemical cells

In a recent paper we developed a Theoretical model built on the assumption that current transients that occur during the electrochemical deposition of species arise from the simultaneous contribution of three basic mechanisms: reaction, diffusion and convection. The theory provided an explanation for the different effects exhibited by voltammograms when natural and irregular convective movements are supposed to develop inside the electrolytic cell. In this paper we examine the underlying physics and the effectiveness of the theoretical model in describing electrochemical processes under forced convection conditions, particularly the effect of hydrodynamic conditions on the current–potential and current–time curves. We also examine the connection among diffusion layer thickness, convective velocity and stationary concentration on the electrode surface, regarding the role they play in the current yields. A comparative study of our model and the one introduced by Hyde and Compton [M.E. Hyde, R.G. Compton, J. Electroanal. Chem. 581 (2005) 224–230.] is performed, revealing similar results despite fundamental differences in the approaches of both theoretical models. The present work shows, from a basic point of view how the stationary current yield results from the interplay of convective velocity and diffusion layer thickness.