Mass and charge transfer kinetics and coulometric current efficiencies. Part V. Comparison of pattern theory, Tafel, Allen and Hickling and Lewartowicz methods, and apparatus and procedures for ramping voltammetry

Abstract

A comparison is made of the provenance and application of pattern theory, Tafel, Allen and Hickling and Lewartowicz methods for the determination of charge-transfer kinetic parameters. A general-purpose electrochemical cell is described together with a ramping potentiostat-galvanostat for slow single-sweep voltammetry. The mass-transfer characteristics, which are governed by the geometrical placing of the various appurtenances that dip into the solution and by the stirring speed, were examined by determining the apparent diffusion layer thickness at various stirring speeds for a system of known mass-transfer properties, copper(II)-copper(I). It was further established that the limiting current of reduction of hexacyanoferrate(III) is reproducible and linearly related to concentration.