Instrumentation, RRDE

Application of the RRDE as a diagnostic tool to explore the mechanism of an unknown reaction pathway relies, as most methods do, on the differences between the different working curves. For the RDE the working curves for different mechanisms in many cases do not deviate sufficiently to allow a distinction between two possible pathways [259]. The presence of the ring electrode provides extra information, and thus the RRDE is a more sensitive instrument for mechanism analysis. An example is the distinction between the RR and the RS dimerization mechanisms for CS2 radical anion [269]. It has been pointed out, however, that even with this electrode setup the working curves do... 

According to Eqn (6.25), the collection efficiency can be calculated if ri, r2, and are known. Table 6.1 lists the calculated collection efficiencies of commercially available RRDEs from Pine Instruments. 

Table 6.1. RRDE Geometric Parameters and Their Corresponding Collection Efficiencies (Commercially Available RRDEs from Pine Instruments) ...

In Chapter 5, the instrumentation of RDE technique including electrode design and electrochemical cell construction have been presented, which are also applicable to RRDE technique. 

What sort of instrumentation would be needed for electrochemical experiments A potentiometry experiment requires little more than a pH meter. A potentiostat or galvanostat can be used for the controlling potential or current in an experiment. In a coulometric procedure, a device to integrate the current (i.e., a coulometer) would also be needed. A hydrodynamic voltammetry [e.g., a rotating disk electrode (RDE)] experiment would require an electrode rotor (to spin the electrode at a precisely known rotation speed), and the rotating ring-disk or RRDE refinement (see below) would necessitate the use of a bipotentiostat so that the disk and ring potentials can be independently controlled. An ac impedance measurement involves the use of a sine-wave oscillator and... 

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