PREPARATION, CHARACTERIZATION AND APPLICATION OF AN ELECTRODE MODIFIED WITH ELECTROPOLYMERIZED CUPTCL6

We report the electropolymerization of K2PtCl6 on various electrode su bstrates by the cyclic scanning of the potential in the presence of Cu Cl2 and in the potential range between 700 and -800 mV (vs. SCE). Cu2 was found to be a necessary ion for the formation and stabilization o f the polymeric film. The potential range of the cyclic scanning was f ound to be crucial for the formation of the: film. An energy dispersiv e X-ray spectrometry study of the modifier film indicates that it cont ains copper, platinum, and chloride ions, respectively. The scanning e lectron microscopy image reveals the formation of the nanometer-sized modifier particles dispersed on the substrate electrode. The electroch emical behavior of the modified electrode was studied in detail in ele ctrolyte solutions containing various cations including Cu2+, H+, Fe3, Cr3+. On the basis of these studies, a mechanism of the electropolym erization on the substrate surface was proposed which suggests for the modifier film a one-dimensional, polymeric, mixed-valent, and negativ e-charge-carrying platinum complex stabilized by the Cu2+/Cu+ as the c ounter ions. The composition of the modifier film is therefore propose d to be [CuPtCl6 . CuPtCl4](n), and denoted as CuPtCl6\GC to signify t he necessary starting components. H+/H, Fe3+/Fe2+ and Cr3+/Cr2+ displa y remarkably reversible redox behavior at the CuPtCl6\GC electrode. Th e modified electrode also displays very good electrocatalytic activity in the oxidation of ascorbic acid, H2O2, S2O32-, and NO. (C) 1998 Els evier Science S.A.