Methanol Oxidation on Pt and Ag

Methanol oxidation on Pt has been investigated at temperatures 350° to 650°C, CH3OH partial pressures, pM, between 5-10 2 and 1 kPa and oxygen partial pressures, po2, between 1 and 20 kPa.50 Formaldehyde and C02 were the only products detected in measurable concentrations. The open-circuit selectivity to H2CO is of the order of 0.5 and is practically unaffected by gas residence time over the above conditions for methanol conversions below 30%. Consequently the reactions of H2CO and C02 formation can be considered kinetically as two parallel reactions. 

The effect of catalyst overpotential and potential on the rates of these two reactions is shown in Figs. 8.45 and 8.46. They both exhibit electrophobic behaviour for Uwr U r and electrophilic behaviour for UWR U, i.e. the reaction exhibits pronounced inverted volcano behaviour. 

Qualitatively similar behaviour for methanol oxidation on Pt/YSZ was reported by Cavalca, Larsen, Vayenas and Haller51 who used the single chamber design51 instead of the fuel-cell type design of the earlier study of Neophytides and Vayenas.50 Cavalca et al51 took advantage of the electrophobic 

---