Electrocatalytic oxidation of cyclohexanol on a nickel oxyhydroxide modified nickel electrode in alkaline solutions

Electrocatalytic oxidation of cyclohexanol was investigated with cyclic voltammograms, linear galvanic voltammograms and chronoamperometric responses on a nickel oxyhydroxide modified nickel (NOMN) electrode prepared by cycling the potential of a nickel electrode in the potential range of 0.1 V to 0.6 V (vs SCE) in alkaline solutions. It was found that cyclohexanol was oxidized by NiOOH generated with further electrochemical oxidation of nickel hydroxide during the anodic potential sweep. One of the products of the reaction between cyclohexanol and NiOOH was Ni(OH)(2) which was subsequently oxidized to NiOOH on the anode. This resulted in the appearance of a new anodic peak in cyclic voltammograms compared with the absence of cyclohexanol and this anodic peak strongly depends upon potential scan rates and cyclohexanol concentrations. In addition, the presence of cyclohexanol in NaOH solutions also lead to the decrease of anodic potentials in linear galvanic voltammetric responses and the increase of current densities in chronoamperometric curves. Results showed that the oxidation of cyclohexanol on the NOMN electrode follows the catalytic reaction mechanism. (C) 2006 Elsevier B.V. All rights reserved.