Platinum anode, linear anodic potential sweep

Fig. 14. Response of smooth platinum anodes during linear anodic potential sweep for ethane adsorption at 0.3 V in 1 Al liOO (174. The anodic and cathodic pretreatment schedule of the electrode is shown at the bottom of the figure. The sweep follows ethane adsorption for time Te, corresponding to the various curves.

Figure 2.19 Linear sweep voltammograms of a platinum electrode immersed in N -saturated 0.5 M H2SO t showing the anodic stripping of adsorbed CO. The CO was adsorbed from the CO-saturated electrolyte for 10 minutes at the designated potential. The scan rate was 1 mV s The adsorption potential was (a) 0.05 V and (b) 0.4 V vs. NHE. Note the different electrode potential scales for the two plots. From Kunimatsu et at. (1986).

The widespread use of large-amplitude relaxation techniques in the investigations of anodic organic oxidations, requires further comment on the value of these methods. Reinmuth divided these techniques into three classes based on the types of applications quantitative kinetic studies, qualitative kinetic studies, and analytical studies. We are not concerned here with the analytical applications. For studies in kinetics, controlled-potential techniques, particularly linear-potential scan, in either single sweep or in cycles, and to some extent chronopotentiometry, have been primarily employed. Chronopotentiometry has been successfully utilized in the study of transient reactions, e.g., the reaction of CO with platinum oxide or the reaction of oxalic acid with platinum oxide, and the study of simple charge-transfer reactions with linear diffusion (cf. Refs. 159-161). However, since the general application of chronopotentiometry is severely limited for the study of anodic organic oxidations, as commented previously, this technique will not be further discussed. The quantitative analysis of data obtained by linear potential scan techniques is complicated because the form of theoretical results even for the simplest cases, requires the use of computers and consequently very little quantitative kinetic information has been obtained. This... 

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