Some specific features of the catalytic role of UPD foreign metal adatoms and water on the anodic oxidation of absolute methanol on Pt

Abstract

In this work the influence of underpotential-deposited foreign metal adatoms on the anodic oxidation of methanol on Pt in absolute methanol solutions of H 2SO 4 and LiClO 4 is studied. Unliked aqueous solutions, the underpotential deposition (upd) of heavy metal ions causes striking catalytic effects for methanol oxidation in absolute methanol solutions. The maximum catalytic activity occurs at particularly high positive potentials where the upd monolayers are already anodically dissolved. An alternative interpretation based on double layer changes as a result of the redissolution of the upd monolayer has been postulated. The effect of small additions of water on the processes both on Pt and Pt/M(upd) surfaces has also been examined.