The Kinetics of Heterogeneous Electron Transfer Reaction in Polar Solvents

Abstract

Data for heterogeneous electron transfer reactions obtained in the last ten years have been examined within the context of contemporary theory. Special attention is focused on systems for which rate constants and activation parameters are available as functions of solvents and of temperataure. The role of reactant structure in deteriming the kinetic parameters is also considered. Double layer effects both at unmodified and modified electrodes are discussed in detail. Experimental techniques, especially those suited to measuring fast reactions, are also outlined.

Fifty years of studies of double layer effects in electrode kinetics—a personal view

“…Needless to say, the discussion at the conference was intense. In the end, the Lewis group was not able to reproduce their results which were attributed to the problems associated with fabricating umes of such small dimensions [51]. In 1992, Marcin Opallo working in Davis applied the Baranski technique to measure the kinetics of electroreduction of buckminsterfullerene in benzonitrile [55].…”

“…These experiments often involved ultrafast cyclic voltammetric methods and were plagued with problems involving iR drop [51]. In 1991, Michael Weaver invited me to give a paper at a symposium he was organizing at the Spring Meeting of the Electrochemical Society in Washington, DC.…”

Misleading aspects of the viscosity effect on the heterogeneous electron transfer reactions

“…A well-known and natural way to change the viscosity of a liquid medium is simply to change a solvent (Refs. [14][15][16][17] give the examples of this approach to ET studies). 1 Usually viscosity is assumed to be proportional to the inverse relaxation time, a key parameter of the dynamic solvent effect in adiabatic ET reactions.…”

New Insights into the Solvent Effect on the Electrooxidation Kinetics of Nickelocene

“…(2) where a is the radius of the reactant, 4 op and 4 s are the optical and static dielectric constants, respectively, 4 o is the vacuum permittivity, and s is the MSA parameter.…”

“…The activation parameters of the charge transfer process are also affected by the dynamic properties of the solvent [2,3]. For an adiabatic reaction, the activation enthalpy ÁH Ã ex is given by Eq.…”