Voltage-step Transient in Redox Systems II. 1D Approximation (revisited)

0346534 - ÚCHP 2012 RIV CZ eng V - Research Report
Wein, Ondřej
Voltage-step Transient in Redox Systems II. 1D Approximation (revisited).
Praha: Ústav chemických procesů AV ČR, v. v. i, 2010. 17 s. 6.
R&D Projects: GA ČR GA104/08/0428
Institutional research plan: CEZ:AV0Z40720504
Keywords : voltage-step transient * cottrell asymptote * ohmic loss
Subject RIV: CI - Industrial Chemistry, Chemical Engineering

Using the well-known Cottrell asymptote, voltage-step transient experiment could provide data on bulk concentration and diffusion coefficient of working depolarizer, essential in the liming-current techniques. However, the Cottrell asymptote is not directly applicable in an early stage of the voltage-step transient process,. There are three additional transport resistances that cannot be neglected at extremely high initial currents: Faradaic resistance at surface of working electrode, Ohmic losses in its intimate neighborhood, and the galvanometric constraint in the outer circuit (galvanometer, current follower, potentiostat). Non-linear effect of these additional transport resistances on the transient current is calculated in a 1D approximation, i.e. assuming uniform accessibility of the working electrode, for finite voltage steps.
Permanent Link: http://hdl.handle.net/11104/0187543