Kinetic and mechanistic study of methanol oxidation on a Pt(100) surface in alkaline media

A comparative study of methanol oxidation on a Pt(100) surface was carried out in bicarbonate, carbonate and different pH values of sodium hydroxide solutions. It was shown that Pt(100) adsorbs OH and 'poisoning species'. The surface activity was directly correlated to the OHad species coverage. The 'poisoning species', produced in methanol oxidation, participate in the reaction at higher potentials, but block the surface partially at lower potentials. A dual path reaction mechanism, common to all the alkaline solutions used, was proposed based on the assumptions that HCO is a reactive intermediate and that a formate is a reaction product in the main path, while CO2 is a product of 'poisoning species' oxidation in a parallel reaction path. (C) 1998 Elsevier Science S.A. All rights reserved.