Fast methanol oxidation on polycrystalline Pt

Fast cyclic voltammetry and a combined chronoamperometry/cyclic voltammetry pulse-sweep technique are used to study methanol oxidation on platinum in sulphuric acid. Measurement of suppression of hydrogen desorption charges simultaneously with charges for stripping of the CO poison allows for accurate baseline correction of the CO stripping peaks. Saturation coverages of CO formed from methanol, formic acid and dissolved CO are not all the same and differ in their potential dependence. Only dissociative adsorption of methanol to give adsorbed CO and subsequent oxidation of CO to CO2 occurs during continuous cycling, but in the pulse-sweep method evidence was found for the existence of a parallel pathway occurring independently of adsorbed CO production, provided there is some surface not covered by CO or oxide.