Preparation, characterization, and electrocatalytic properties of copper hexacyanoferrate film and bilayer film modified electrodes

Copper(II)hexacyanoferrate films have been prepared from various electrolyte aqueous solutions using consecutive cyclic voltammetry. The cyclic voltammograms recorded the direct deposition of copper(II)hexacyanoferrate films from the mixing of Cu2+ and Fe(CN)(6)(3-) ions from solutions of ten cations: Li+, Na+, K+, Rb+, Mg2+, Ca2+, Sr2+, Ba2+, H+ and Al3+. An electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry were used to study the in situ growth of the copper(II)hexacyanoferrate films. The copper(II)hexacyanoferrate film showed a single redox couple that exhibited a cation effect (Li+, Na+, K+, Rb+ and Cs+) and an anion effect (F-, Cl- and Br-) in the cyclic voltammograms and formal potential of the redox couple. The electrochemical and EQCM properties of the film indicate that the redox process was confined to the immobilized copper(II)hexacyanoferrate, and the interaction between the copper(II)hexacyanoferrate film with K+ (monovalent cation) and Ca2+ (divalent cation). The electrocatalytic oxidation properties of NADH, NH2OH, N2H4, SO32- and S2O32- were also determined. The electrocatalytic reduction properties SO52- and S2O82- by monolayered iron, nickel, and cobalt hexacyanoferrate films, and by bilayered metal-copper hexacyanoferrate films were determined. Two-layered modified electrodes and hybrid films composed of a copper(II)hexacyanoferrate film with iron(II)hexacyanoferrate, cobalt(II)hexacyanoferrate, or nickel(II)hexacyanoferrate film were prepared, and these films caused the electrocatalytic reduction SO52- and S2O82-. (C) 2003 Elsevier Science B.V. All rights reserved.