The Mediatory Activity of Ce(IV)/Ce(III)Redox System Immobilized in Nafion~R Film on Glassy Carbon

摘要

Properties of the glassy carbon modified with Ce(III)ions immobilized in Nafion film and the catalytic activity of these ions or the catalytic activity of the modified conducting phase in electrochemical oxidation of some hydroquinone,phenylenediamine and 4-hy-droxybenzoic acid derivatives were investigated.The redox activity was characterized in aqueous solutions of perchloric acid by cyclic voltammetry.The redox process was diffusion-limited which can suggest that the cerium(III)ions immobilized in the Nafion multilayer was rate-controlling.The increase of anodic peaks of investigated compounds during oxidation on the modified electrode(GC/Nafion/Ce(III)),and drastic decrease of cathodic peak related to Ce(IV)ions reduction,points to the mediatory activity of these ions.The increase of oxidation currents observed during preparative electrolyses indicates the catalytic properties of the modified conducting phase.The preparative electro-oxidation of investigated compounds showed that the 100% conversion of the substrate occurs in the shortest time on glassy carbon modified with Ce(III)ions immobilized in Nafion film.AFM tapping mode phase imaging was used to identify the hydrophobic and hydrophilic regions of Nafion perfluorosulfonate cation exchange membranes.The clusters agglomerates have a range of sizes from 5 to 30 nm.