Tin oxide surfaces. Part 3.—Infrared study of the adsorption of some small organic molecules on tin(IV) oxide

Abstract

The tin(IV) oxide surface is strongly oxidising towards small, reactive organic molecules. Methanol is chemisorbed to give methoxy groups but these are readily oxidised to a surface formate at temperatures 320 K. Acetone and acetaldehyde are adsorbed predominantly as acetates but some evidence is found for an enol form which may be responsible for the rapid deuterium exchange between hexadeuteroacetone and surface hydroxyl groups. The spectra of the formate and acetate structures are confirmed by adsorption of formic and acetic acids, where evidence is also found for undissociated acid molecules bonded to the surface. As expected the acetate is thermally more stable than the formate under vacuum.