Split ring disc electrode

Sakashita M, Lochel B, Strehblow HH (1982) An examination of the electrode reactions of Te, HgTe and Cdo.iHgo.sTe with rotating-split-ring-disc electrodes. J Electroanal Chem 140 75-89... 

However, the application of the Split Ring Disc electrode especially with hydro-dynamic modulation of its rotation speed (HMRRD) will be mentioned briefly. The construction of appropriate ring disc electrodes including a modified commercial disc rotator and the necessary electronic tripotentiostat have been already described in detail elsewhere [25]. The investigations of K.G. Heusler on passive iron in 0.5 M sulphuric acid have been already mentioned [18]. Another example is shown for Cu in alkaline solution [26]. Two half rings permit determination of the formation of two Cu species simultaneously. The transfer efficiency from the disc to the ring has been... 

A variant of the RRDE in which the ring is split into two parts (the rotating split ring-disk electrode) was invented to enable the detection of different intermediates produced at the disc electrode [32]. It was shown that the current at the ring segments is proportional to the length and that there is no interference between the segments [9, 33]. 

Fig. 9. Polarization curve of an Fe-disc Pt-split-ring electrode with hydrodynamic square wave modulation. In 1 M NaOH with anodic and cathodic scan including capacity of the Fe disc (dashed curve), modulation frequency of rotation co = 0.05 Hz (insert), simultaneous detection of Fe(II) and Fe(III) ions at Pt half rings [12].

Fig. 16 The stages of breakdown of passivity of iron in 1 M HCIO4 after addition of 0.1 M H F at t = 0 min examined with a RRD electrode with a Pt split-ring and an Fe-disc of A = 0.112 cm, ...

Most electrochemical cells consist of three electrodes working electrode, counter electrode, and reference electrode. In some applications, however, the working electrode is split into several separate electrodes, e.g., in rotating disc/ring systems (Rotating Disc Electrode). This requires an independent potential control of the working electrodes. 

Using a split RDE, one may analyze two products simultaneously, i.e., the dissolution of Cu+ and Cu " or of Fe and Fe. These measurements require a tripotentiostat, which allows setting the electrode potentials for the disc and the two rings independently whereas an RRD electrode requires a bipotentiostat only. For these measurements, the electronic circuits require a common RE and a grounded CE. Differential amplifiers at the entrance of the three (or two) potentiostats uncouple the WEs (rings and disc) so that the whole circuit is grounded at one point. The related equipment and the procedure to produce electrodes for corrosion studies is described in the literature [45-47]. 

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