Oxide formation as probe to investigate the competition between water and alcohol molecules for OH species adsorbed on platinum

Abstract

The creation of defects on the surface of Pt(111) and Pt(100) and the dissolution of Pt were used as probes to investigate the oxidation of the surface in the absence and in the presence of methanol, ethanol, glycerol and ethylene glycol. Electrochemical and Graphite Furnace Atomic Absorption Spectrometry showed that in the presence of ethanol, glycerol and ethylene glycol, in the same potential window, the formation of defects is decreased in comparison to the oxidation of platinum in the absence of these alcohols. Since both the oxidation of the alcohols and the oxidation of the surface depend on PtOH formation, the competition for this species can displace the potential at which the oxidation of the surface oxidation to PtO is favored in the presence of ethanol, glycerol and ethylene glycol. On the other hand, the presence of methanol does not influence the oxidation and subsequent disordering of the surface, possibly because this reaction takes place in parallel with platinum oxidation to PtO.