Polaromicrotribometric study of a hydrophobic polymer film on platinum electrode during Kolbe electrosynthesis in aqueous media
✍ Scribed by F. Bruno; J.E. Dubois
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 844 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0013-4686
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✦ Synopsis
The presence of a polyethylene fXm at the surface of a platinum electrode has been established, during the anodic oxidation of aqueous acetate solutions, by means of a new method of investigation of polarized metallic surfaces : polaromicrotribometry. Analysis of the gaseous reaction products and a classical electrochemical study (current/potential curves, galvanostatic discharging transients) carried out at the same time, have shown that this hydrophobic film is formed at the critical potential of 204 V(sce), where the KoJhe reaction starts, and that it is adsorbed on the platinum through a monolayer of oxygen. This film, we suggest, is responsible for the inhibition of oxygen formation and controls the diffusion of electro-active species towards the electrode and thereby controls the kinetics of the Kolbe reaction. R6%m&Nous avons caract&% ia prksence d'un film de poly&hyl&e B la surface de 1'6Jectrode de pJatine poli, au tours de l'oxydation anodique des ions a&ate en solution aqueuse, & l'aide d'une m&hode nouvelle d'&ude des surfaces m&aJJiques polarides: la polaromicrotribom&ie. L'anaJyse des prod&s gazeux de la rkaction et I'&ude dlectrochimique classique (courbes intensit6/potentieJ, courbes de d&charge galvanostatique) effect&es conjointement montrent que ce film hydrophobe se forme au potentiel critique de 2,04 V (ecs) (debut de la rbaction de Kolbe) et qu'il est adsorb6 sur le platine il travers une monocouche d'oxygtine. Nous avancons que ce film est responsable de I'inhibition de la reaction de formation de l'oxyg&ne et qu'en contralant Ia diiusion des espties &&oactives vers J'CJectrode iJ regit la cin&ique de la reaction de KoJbe.