Electrochemical preparation of a composite gold-cobalt electrode and its electrocatalytic activity in alkaline medium

A chemically modified electrode composed of cobalt(III) oxyhydroxide film dispersed on the gold substrate (Au-Co) was characterised by cyclic voltammetry. Electrochemical deposition of the cobalt film was accomplished by cycling the potential between 0.0 V and 1.1 V (vs. saturated calomel electrode (SCE)) in 0.1 M acetate solution (at pH 7.3) containing 10 mM CoCl2. The effects of several experimental parameters (pH, applied potentials, etc.) on the film formation and growth were evaluated. The electrochemical behaviour of the Au-Co composite electrode was investigated in alkaline medium. The film appears uniform and compact and shows good electrical conductivity and electrochemical activity towards the oxidation of several scarcely electroactive organic molecules. The concomitant presence on the electrode surface of both active catalysts leads to a wide range of potential applications where a significant electrochemical activity towards the electrooxidation of several classes of organic compounds is observed. (C) 1999 Elsevier Science Ltd. All rights reserved.