Rotating ring-disk electrode RRDE

Data on the electrochemistry of the telluride ion in alkaline media are relatively limited. Mishra et al. [53] studied the oxidation of Te to Te° at solid electrodes, focusing on the intermediate step(s) of this process, and in particular, the possibility of detecting ditelluride Te via rotating ring disk electrode (RRDE) methodology. Oxidation beyond the elemental state to TeO and TeO was also studied using cyclic and hydrodynamic voltammetry. 

The ORR has been studied with a rotating ring-disk electrode (RRDE), which can provide theand the H2O2 yield P(H202) at around room temperamre. However, for improving the ORR activity, PEFCs should be operated at high temperature (> 80 °C). In this section, we demonstrate the temperature dependencies of ORR activity and P(H202) at pure Pt (both bulk and supported catalyst) and bulk Pt alloys (Pt-Ni, Pt-Co, and Pt-Fe). 

Thin catalyst layers on a GC rotating disk electrode (RDE) or a rotating ring-disk electrode (RRDE) serve for studies of ORR kinetics. In order to separate the kinetic current from the measured current j, Schmidt and co-workers [Schmidt et al., 1998b] corrected the latter for the influence of oxygen diffusion in the aqueous electrolyte and in the polymer film using the foUowing equation ... 

In the most common approach, a water-insoluble metaUoporphyrin is deposited on the surface of a rotating disk electrode (RDE) or on the disk of a rotating ring-disk electrode (RRDE Fig. 18.7a) as a film of poorly defined morphology, either by spontaneous adsorption from a solution of the catalyst in an organic solvent or by evaporation of an aliquot of such a solution onto the electrode. It is impossible to know the... 

Figure 18.7 (a) Rotating ring-disk electrode (RRDE left) and schematics of chemical... 

Despite the importance of the ORR and long history of study, very little is known about the reaction mechanism.126,130,131 Mechanistic information has been derived almost exclusively from rotating disk electrode (RDE)131,132 and rotating ring disk electrode (RRDE)133-136,62,128 studies. The rotating electrode minimizes mass transfer effects and allows a kinetic current density to be extracted. In the RRDE setup, the ring surrounding the disk electrode detects species weakly adsorbed to the electrode that are ejected due to electrode rotation. The ORR reaction (eqn 4) is... 

Since products of the electrode process are quickly transported out of the vicinity of the electrode disk, use of the rotating disk electrode complements the more complex rotating ring disk electrode (RRDE) [32]. Here, redox active products can be detected at the ring electrode, which is held at a separately controlled potential. 

Figure 3.39 (A) Rotating-disk electrode with hydrodynamic flow pattern. (B) Bottom view of rotating-disk electrode (RDE) and rotating ring-disk electrode (RRDE).

Another voltammetric method, rotating ring-disk electrode (RRDE) voltammetry, was applied to study the same reaction and excellent agreement was found with the DPSC results. The studies were conducted at temperatures as low as -78°C and at rotation rates between 500 and 6000 rpm. Unlike DPSC, analysis of the RRDE data required knowledge of both the kinematic viscosity of the solution and the diffusion coefficient of the reactant at each temperature, so it was necessary to measure these quantities to complete the analysis. 

Dry boxes are especially advantageous for rotating ring-disk electrode (RRDE) experiments [6]. Because the motor can be placed in the dry box, one is saved the expense of a rather expensive RRDE cell and sealed motor and the attendant problems of working outside the dry box. 

Early work in our laboratory involved the examination of competitive photoanodic oxidation at a CdS electrode in electrolytes containing various reducing agents using the rotating ring-disk electrode (RRDE) technique.20 In the... 

Rotating Ring-Disk electrode (RRDE-) experiments... 

The inlaid disk and inlaid ring electrode can be combined to make an inlaid electrode in which the disk forms the interior which is surrounded by the ring. This is called a ring-disk electrode and when the entire assembly is rotated about its vertical axis it is referred to as a rotating ring-disk electrode (RRDE). Figure 4 illustrates a rotating disk electrode (RDE). 

Rotating ring disk electrode (RRDE) — This electrode consists of a thin metallic ring inlaid around the metallic disk that is situated in the center of the base of the insulating cylinder. Because of the radial component of the solution movement, which is caused by the rotating of the cylinder, the products of the electrode reaction formed on the disk electrode are carried over the... 

Electrochemical Methods Rotating Disk Electrode (RDE) and Rotating Ring Disk Electrodes (RRDE)... 

---