Category: 06. Electroanalytical Techniques and Analysis of Electrochemical Systems

Microelectrodes are electrodes whose characteristic dimension is only a fraction of a millimeter. They represent an important tool for electroanalytical measurements. In this section, we examine some of the advantages and disadvantages of these electrodes. Two examples of microelectrode geometries are shown in Figure 6.28, but the general concepts developed here can be applied to other…

Ideally, we would like to measure or control the potential of the WE relative to the RE, where the reference electrode is just outside the diffuse double layer of the working electrode. Unfortunately, it is not possible to do so. There are two principal concerns: first, the degree to which the physical presence of the…

The rotating disk electrode (RDE) is shown in Figure 6.20. Here an electrode is imbedded in the end of a cylinder, which rotates submerged in the electrolyte. The electrode is typically a smooth surface surrounded by an insulating material such as Teflon. The RDE merits special attention for several reasons. First, the hydrodynamics for the RDE…

Fundamentals As mentioned previously, one of the key objectives of electroanalytical methods is to quantify the relationship between the current and voltage and to provide insight into the processes that influence that relationship. The simplest relationship is Ohm’s law: (6.17) which we have already used frequently. In this relationship, the resistance, RΩ, is the proportionality constant…

The underlying principle used in this type of analysis is that a quantitative amount of material is either deposited or removed from a surface or from an amalgam electrode. Because the coulombs passed can be measured very accurately, information about the surface area of an electrode or about the concentration of a metal species in…

Cyclic voltammetry (CV) is a useful analytical tool for electrochemical engineers. It is often the first test performed to characterize a new electrolyte or an electrode. You will need to be familiar with the basic experiment and the interpretation of the data in order to obtain quantitative information. We begin at a potential that is…

Recall from Chapter 3 that the surface of the electrode is usually charged, and that the structure of the interface is described as a double layer. The charge associated with the double layer depends on the electrode potential, and current must flow to alter this charge as either more or less charge is stored at the interface…

As shown in Figure 6.3, we consider a planar WE located at x = 0. The CE is located sufficiently far from the working electrode so that it has no effect on the results. The reference electrode is assumed to be positioned just outside of the double layer. As before, the potential of interest is the potential of the…

There are a multitude of experiments that can be performed with the basic three-electrode setup described above. Through a series of examples, we will explore a few of the more common ones, highlighting the main information that is obtained from each and its advantages and disadvantages. The key features of the any experiment are (1)…

The basic electrochemical cell used for analysis of electrochemical systems consists of three electrodes: the working electrode (WE), the counter electrode (CE), and a reference electrode (RE). The three-electrode setup is shown in Figure 6.1. The working electrode is where the electrochemical reaction being studied occurs. Typically, the potential or current of the working electrode is…