Ring-Disk Voltammetry

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 iron complex (23) adsorbed on graphite electrode surfaces is an active catalyst for the electroreduction of both nitrite and nitric oxide to yield NH2OH and NH3, as demonstrated by rotating ring-disk electrode voltammetry experiments.341... 

Another type of polymeric structure is based macrocyclics or on stacks of macro-cyclic units. An exhaustive electrodynamic investigation of the polymer derived from yU.-oxo-(tetra-ferf-butylphthalocyaninato)germanium and of the monomer was carried out using CPE, CV, voltammetry by RDE, rotating ring-disk electrode and differential pulse... 

Voltammetry at Rotating Disk and Rotating Ring-Disk Electrodes... 

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. 

The advantages of a solid electrode of fixed area that functions in the voltammetric experiment with a constant diffusion-layer thickness have led to the development of the rotated-disk and ring-disk electrodes.52-54 By rotation of a disk, the electrode diffusion layer becomes fixed such that the current is constant as a function of time and does not decay [in contrast to conventional voltammetry Eq. (3.6)]. Voltammetry with such an electrode system gives a current-potential wave that is analogous to a polarogram and follows the relationship... 

Another specialized form of voltammetry involves the use of either a rotated-disk or a ring-disk indicating electrode. With this type of electrode the current is directly proportional to the square root of the rate of rotation if it is a diffusion-controlled process. To obtain complete adherence to the square-root relationship, a hydrodynamically sound design for the electrode is essential.43 Figure 3.12 illustrates the geometric features that have been found to give reliable performance for rotation rates as high as 10,000 rpm. 

Hydrodynamic electrodes — are electrodes where a forced convection ensures a -> steady state -> mass transport to the electrode surface, and a -> finite diffusion (subentry of -> diffusion) regime applies. The most frequently used hydrodynamic electrodes are the -> rotating disk electrode, -> rotating ring disk electrode, -> wall-jet electrode, wall-tube electrode, channel electrode, etc. See also - flow-cells, -> hydrodynamic voltammetry, -> detectors. 

Photosensitized Electrolytic Oxidation of Iodide Ions on Cadmium Sulfide Single Crystal Electrode. The stability of CdS probe under irradiation in an electrolyte containing iodide species. Rotating ring disk voltammetry was used as the methodology. 487... 

Hydrodynamic (rotating-disk and ring-disk) voltammetry 60, 62 72... 

---