Kinetic and mechanistic study of methanol oxidation on a Pt(110) surface in alkaline media

The comparative study of methanol oxidation on a Pt(110) surface was carried out in bicarbonate, carbonate and sodium hydroxide solutions. It was shown that OH- electrosorption precedes the oxide layer formation in sodium hydroxide solution and is coupled by HCO3- and CO32- electrosorption in the corresponding media. Adsorbed bicarbonates suppressed the methanol oxidation. The surface activity was correlated to the OHad species coverage. Coverage with 'poisoning species' formed during methanol oxidation is time dependent. The dual path mechanism for methanol oxidation on the Pt(110) surface, as well as for the other low-index planes, was proposed based on the assumptions that HCOad and OHad are reactive intermediates and that formate is the reaction product in the main path, while CO2 is a product of 'poisoning species' oxidation in a parallel reaction path. (C) 1998 Elsevier Science Ltd. All rights reserved.