Voltage-step Transient in Redox Systems III. Effect of the Current Primary Distribution via Nernst Model

0360483 - ÚCHP 2012 RIV CZ eng V - Research Report
Wein, Ondřej
Voltage-step Transient in Redox Systems III. Effect of the Current Primary Distribution via Nernst Model.
9. - Praha: Ústav chemických procesů AV ČR, v. v. i, 2010. 20 s.
R&D Projects: GA ČR GA104/08/0428
Institutional research plan: CEZ:AV0Z40720504
Keywords : distributed nernst model * ohmic and faradic resistance * primary current distribution
Subject RIV: CI - Industrial Chemistry, Chemical Engineering

In addition to the common transient diffusion (Cottrell), there are further transport results that cannot be neglected: Faradic resistance at surface of the working electrode, and Ohmic resistance in the bulk of streaming electrolyte solution between the working and counter electrodes. These additional resistances are analyzed here for the voltage-step transient (VST) process using the Nernst model of a two-electrode cell (no reference electrode). The Faradic resistance is considered for a single redox couple O + ne- = R according to Butler-Volmer electrode kinetics. The effect of Ohmic and Faradic resistances in VST is accounted for using two models: the recently updated 1D approximation and a new model that accepts primary current distribution for a circular electrode. It is shown that the 1D approximation introduces unacceptable errors.
Permanent Link: http://hdl.handle.net/11104/0198022