STM studies of methanol oxidation to formate on Cu(110) surfaces: II. codosing experiments

We have used STM to study Cu(110) surfaces exposed to mixtures of oxygen an d methanol (CH3OH, CD3OD, and CD,OH), attempting to follow the methodologie s employed by recent XPS and TPD studies of this system. We find that where as some methoxy and formate can be produced by exposing these surfaces to m ethanol/oxygen mixtures, prolonged exposure results in primarily oxygen-cov ered surfaces. We explain this by demonstrating the ability of oxygen to ap parently displace methoxy from these surfaces. Subtle differences have been observed, depending on whether CH3OH or CD3OH is used. We demonstrate that attempts to codose oxygen and methanol while simultaneously using the STM to image the surface can affect the local surface topography, resulting in the creation of areas that are unrepresentative of the surface as a whole. (C) 1999 Elsevier Science B.V. All rights reserved.