Characterisation of platinised Ti mesh electrodes using electrochemical methods: methanol oxidation in sodium hydroxide solutions

Abstract

Characterisation of a platinised Ti mesh electrode, prepared by electrodeposition of Pt, by methanol oxidation has been studied over a range of NaOH and methanol concentrations using cyclic voltammetry (CV), quasi-steady-state polarisation, and electrochemical impedance spectroscopy (EIS). The activity of methanol oxidation in aqueous alkaline systems increased with pH or OH species coverage on the electrode surface. A reaction order of close to 0.5 was obtained for both NaOH and methanol in NaOH solutions indicating that adsorption of methanol and OH− on the platinised electrode follows Termkin isotherm. In the high potential region, a poisoning effect was observed at methanol/[OH−] concentration ratio greater than 1, which could have arisen from an excess of methanol at the electrode surface and/or depletion of OH− at the electrode surface. The methanol oxidation behaviour conforms with that on Pt electrodes suggesting a promising new method of preparing electrodes for fuel cells.