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The auxiliary electrode may be isolated from the working electrode using a glass frit. Such isolation prevents any byproducts generated at the auxiliary electrode from contaminating the main test solution: for example, if a reduction is being performed at the working electrode in aqueous solution, oxygen may be evolved from the auxiliary electrode.
The counter electrode, also known as the auxiliary or second electrode, can be any material that conducts current easily, will not react with the bulk solution, and has a surface area much larger than the working electrode. Common choices are platinum and graphite. Reactions occurring at the counter electrode surface are unimportant as long as ...
This isolates the undesired redox events taking place at the auxiliary electrode. During bulk electrolysis, the analyte undergoes a redox event at the working electrode. If the system was open, then it would be possible for the product of that reaction to diffuse back to the auxiliary electrode and undergo the inverse redox reaction.
Both of these electrodes are balanced by a single reference and auxiliary combination for an overall four-electrode design. More complicated experiments may add working electrodes, reference, or auxiliary electrodes as required. [7] In practice it can be important to have a working electrode with known dimensions and surface characteristics.
In analytical chemistry, hydrodynamic voltammetry is a form of voltammetry in which the analyte solution flows relative to a working electrode. [ 1 ] [ 2 ] In many voltammetry techniques, the solution is intentionally left still to allow diffusion -controlled mass transfer .
This cylinder, referred to as an electrode is then put into a large cylindrical enclosed crucible and brought to a metallurgical vacuum (0.001–0.1 mmHg or 0.1–13.3 Pa). At the bottom of the crucible is a small amount of the alloy to be remelted, which the top electrode is brought close to prior to starting the melt.
Potentiometry passively measures the potential of a solution between two electrodes, affecting the solution very little in the process. One electrode is called the reference electrode and has a constant potential, while the other one is an indicator electrode whose potential changes with the sample's composition. Therefore, the difference in ...
An RDE cannot be used to observe the behavior of the electrode reaction products, since they are continually swept away from the electrode. However, the rotating ring-disk electrode is well suited to investigate this further reactivity. The peak current in a cyclic voltammogram for an RDE is a plateau like region, governed by the Levich ...