Redox behaviour of Cu2+/Cl− system at poly-4-(2-pyridylazo)resorcinol modified Glassy Carbon Electrodes

✍ Scribed by Dr. H. A. Abd El-Rahman; H. H. Rehan

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 672 KB
• Volume: 23
• Category: Article
• ISSN: 0933-5137
• DOI: 10.1002/mawe.19920230707

✦ Synopsis

Abstract

Thin, adherent and stable polymeric films of 4‐(2‐pyridylazo)resorcinol (abbreviated as PPAR) were prepared by oxidative polymerization in 0.2 M NaOH solutions. PPAR films deposited on GC electrodes were found to inhibit the electron transfer reactions of the couple [Fe(CN)~6~]^3−/4−^. The redox behaviour of CuCl~2~ in 0.5 M KCl at bare and PPAR‐covered GC electrodes was studied by cyclic voltammetry, RDE voltammetry and chronoamperometry. At PPAR‐covered electrodes the peak potential of deposition of Cu occurs at ≃ 260 mV more cathodic potential than bare electrodes whereas the redox peaks of Cu^2+/1+^ and the oxidation of Cu → Cu^1+^ occur at the same potentials. Catalysis of thc redox processes of the couple Cu^2+/1+^ at PPAR‐covered electrodes is attributed to incorporation of the redox species by chelation and electrostatic attraction. The diffusion coefficient of Cu^2+^ species (D = 0.29 × 10^−5^cm^2^ S^−1^) at PPAR‐covered electrodes was found to be less than at bare electrodes (D = 0.95 × 10^−5^ cm^2^ S^−1^) whereas the effective bulk concentration (C = 28 mM) is higher than the used concentration: 10 mM.