Electrocatalytic properties of nickel(II) hydrotalcite-type anionic clay: application to methanol and ethanol oxidation

Glassy carbon electrodes modified with a [Ni/Al-Cl] hydrotalcite-type anion ic clay have been studied with respect to the electrochemical oxidation of the NI(II) centres. The oxidation of Ni(II) is quasi-reversible and the pre sence in the hydrotalcite lattice of nickel with mixed oxidation states inc reases the conductivity of the coverage strongly. It has been verified that these nickel redox systems may act as redox mediators for the oxidation of alcohol substrates (methanol and ethanol have been tested) which are not o xidised at the bare electrode in the potential window available. For both a lcohols the height of the current responses in linear sweep voltammetry is roughly linear with varying concentration in solution up to a limit of ca. 3000 ppm, with a detection limit of 3-4 ppm. (C) 1999 Elsevier Science S.A. All rights reserved.