Electrodes roles and experimental considerations

As alluded to in the introduction a typical voltammetric experiment utilizes three types of electrode. 

This is the electrode at which the reaction of interest takes place, e.g. the simple one-electron oxidation-reduction processes given in equations (1) and (2). 

Typically these electrodes are fabricated from an inert and electrically conducting material. Common examples would range from liquid mercury to solid platinum and some forms of carbon (i.e. glassy carbon or graphite). Mercury electrodes (Bond, 1980) are used in the form of dropping electrodes in which the surface is continuously renewed or a hanging mercury drop electrode. Recently diamond film electrodes have been utilized for studies that require wide potential windows (Tenne et al., 1993). Typically, the solid 

This electrode provides a fixed reference couple against which the potential of the working electrode is measured, e.g. the aqueous silver/silver chloride reference electrode utilizes the couple 

In order to satisfy the necessary criteria, a reversible redox couple is utilized in the reference electrode half-cell reaction. The potential of a reversible reference electrode is thermodynamically defined by its standard electrode potential, EP (see for example Compton and Sanders, 1996, for further discussion). Currently, the most commonly used reference electrode in voltammetric studies is the silver/silver chloride electrode (3), which has overtaken the calomel electrode (see for example Bott, 1995) for which the reaction is (4). 

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The two major classes of voltammetric technique 4 Evaluation of reaction mechanisms 6 General concepts of voltammetry 6 Electrodes roles and experimental considerations 8 The overall electrochemical cell experimental considerations 12 Presentation of voltammetric data 14 Faradaic and non-Faradaic currents 15 Electrode processes 17 Electron transfer 22 Homogeneous chemical kinetics 22 Electrochemical and chemical reversibility 25 Cyclic voltammetry 27 A basic description 27 Simple electron-transfer processes 29 Mechanistic examples 35... 

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