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

• Published in: Electrochimica acta 2004-06, Vol.49 (15), p.2443-2452
• Main Authors: Yu, Eileen Hao, Scott, Keith, Reeve, Robert W., Yang, Lianxi, Allen, Ruth G.
• Format: Article
• Language: English
• Subjects: ac impedance; Chemistry; Electrochemistry; Exact sciences and technology; General and physical chemistry; Hydroxide coverage; Kinetics and mechanism of reactions; Methanol oxidation; Platinised; Poisoning effect; Ti mesh
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2004.01.022

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.