Investigation of catalytic effect for methanol oxidation on nickel-zinc coated graphite electrode

Electrode which nickel was deposited on a graphite electrode at different deposition current densities and thicknesses was prepared for methanol oxidation. After determining the best deposition conditions, co-deposits of Ni with Zn were deposited on the graphite electrode. The NiZn coatings prepared on the graphite electrode (NiZn) were etched in a concentrated alkaline solution (30% NaOH) for twent-four hours to produce a porous and electrocatalytic surface suitable for use in the oxidation of methanol. After the leaching process, a low amount of metals was deposited onto the etched NiZn deposit in order to further improve the catalytic activity of the electrode for the methanol electrooxidation. The effect of coatings on the graphite electrode for methanol oxidation was investigated in 1,00 M KOH solution containing 1,00 M Methanol by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) techniques. Chemical composition of layers after alkaline leaching was determined by energy dispersive X-ray (EDX) analysis. The surface morphologies of coatings were investigated by scanning electron microscopy (SEM). It was found that, the oxidation of methanol of coatings depends on the metal ratio, deposition current density and the thickness of coatings C/NiZn-Pd and C/NiZn-Pt coatings have a compact and porous structure as well as good electrocatalytic activity for the methanol oxidation in alkaline media.