Organic Electrolyte Layer on Electrodes

In 1998, Shi and Anson reported an original method to study heterogeneous electron transfer at ITIES [276]. The gist of this approach is to coat a pyrolytic graphite electrode with a thin layer of nitrobenzene and to immerse it in an aqueous 

FIGURE 1.32 (a) Schematic diagram of the application of SECM in the feedback mode measurement of the kinetics of ET between ZnPor in benzene and RufCN) in water. Electroneutrality maintained by distribution of perchlorate ions across the interface. (b) Dependence of the effective heterogeneous rate constant on potential drop across the ITIES at 5 mM concentrations of RufCN) . The value A ( ) is expressed in terms of log[ClCf ]. Potential dependence of an effective bimolecular rate constant k) k f/[Ru(CN)g ] (M cm-s ). (Tsionsky, M., A. J. Bard, and M. V. Mirkin, 1996, J Phys Chem-US, Vol. 100, p. 17881. Used with permission.) 

In subsequent papers, the same authors developed the technique further. In particular, they showed that it was very well suited for the study of metallopor-phyrins [277]. However, when using different solvents such as 4-methylben-zonitrile, chloroform, or benzene, they also showed that the coupling between ion-transfer and electron-transfer reactions can render the quantitative analysis difficult [278-280]. 

Finally, Chung and Anson also showed that thin organic films are very useful in the study of proton-coupled redox reactions such as the reduction of tetrachlo-ro-l,4-benzoquinone in nitrobenzene or benzonitrile [281]. 

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