Methanol electrooxidation on a nickel electrode modified by nickel-dimethylglyoxime complex formed by electrochemical synthesis

Nickel-dimethylglyoxime complex (NiDMG) modified nickel electrode (Ni/NiDMG) showed a catalytic activity towards methanol oxidation in NaOH solution. The modified electrode prepared by the dimethylglyoxime anodic deposition on Ni electrode in the solution containing 0.20 mol L-1 NH4Cl + NH4OH (pH 9.50) and 1.0 X 10(-4) mol L-1 dimethylglyoxime. The modified electrode conditioned by potential recycling in a potential range of 100-700 mV (vs. SCE) by cyclic voltammetry in alkaline medium (0.10 M NaOH). The results show that the NiODMG film on the electrode behaves as an efficient catalyst for the electrooxidation of methanol in alkaline medium via Ni(Ill) species formed on the electrode with the cross exchange reaction occurring throughout the film at a low concentration of methanol. A plausible mechanism was proposed for catalytic oxidation of methanol at NiODMG-modified Ni electrode. Moreover, the effects of various parameters such as anodic deposition time, anodic deposition potential (both in modification step), potential scan rates, methanol concentration and media temperature on the electrooxidation of methanol were investigated. (c) 2005 Elsevier B.V. All rights reserved.