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Development of electrocatalytic materials based on the mixed addenda Dawson heteropolyanion and conducting polymers
|Monika Goral 1, Iwona A. Rutkowska 1, Paweł J. Kulesza 1, Christian Perruchot 2, Mohamed Jouini 2, Timothy McCormac 3, Eithne Dempsey 3|
1. Warsaw University, Faculty of Chemistry, Pasteura 1, Warszawa 02-093, Poland
Over the last several years, there has been a growing interest in heteropolyanions (HPAs), especially in the field of chemically modified electrodes owing to reversible redox activities of HPAs and their excellent electrocatalytic properties towards a range of substrates like nitrite . They also exhibit fast mediating capabilities during electroreductions . An important aspect of an electrochemical based sensor is the successful immobilisation of the electrocatalyst on the electrode surface. Several techniques such as layer-by-layer assemblies , incorporation into polymeric films  have been employed to attach HPAs to different surfaces. Here we report a comparative study concerning the immobilisation of the Dawson type mixed addenda HPA, [P2W17VO62]8- in different conducting polymers, such as polypyrrole, PPy, poly(3,4-ethylenedioxythiophene), PEDOT, poly(2, 2’-bithiophene), PBT.
Functionalisation of conducting polymers, CPs by the incorporation of different functional molecules develops their functions. In addition, CPs are considered to be suitable matrices as their conductive properties and compabilities to molecule and ions may be used to convey the electronic structure and properties of the immobilised species. The [P2W17VO62]8- was chosen in this study because V-substituted Dawson-type HPAs were previously presented as versatile electrocatalysts. Moreover, the presence of V atom(s) within the Dawson type V-substituted HPAs was shown to be beneficial in driving their pH stability domains towards high values .
The [P2W17VO62]8- was successfully immobilised in PPy films. These films were stable at pH 2 and 7 upon continuous potential cycling through V5+/4+ redox process. However, in the negative potential region where the polymer backbone was reduced, the HPA leached out of the film. Investigation of the other conducting polymers, i.e. PEDOT and PBT proved valuable. Especially, in the case of the former polymer, the film was stable in the negative potential window as PEDOT remained in conducting state. Consequently it was possible to view the tungsten-oxo redox processes clearly defined. Furthermore, the electrocatalytic properties of the formed films were investigated. For instance the [P2W17VO62]8- – PPy hybrid films showed electrocatalytic activity towards the oxidation of ascorbic acid. Therefore, applications of the investigated systems in the electrocatalysis and analytical sensing can be predicted.
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Presentation: Poster at SMCBS'2009 International Workshop, by Monika Goral
See On-line Journal of SMCBS'2009 International Workshop
Submitted: 2009-09-07 19:06 Revised: 2009-09-07 19:06