AN FTIR SPECTRAL INVESTIGATION OF THE STRUCTURAL SPECIES FOUND ON ALUMINA SURFACES

The diffuse reflectance infrared Fourier transform (DRIFT) spectra of several alumina powders indicate a mixture of bayerite and gibbsite as well as a dawsonite-like species on the surface. These latter surface species were formed by the reaction of surface sodium ion impurity al ong with water vapor and carbon dioxide adsorbed on the surface. The p resence of sodium ions on the alumina surface enhanced the adsorption of carbon dioxide by the formation of a dawsonite-like species. The sp ectral results for this study can also be related to earlier results f or carbon dioxide adsorption on gamma-alumina (catalyst), and provide a new approach to interpret the infrared bands at 1520-1570 cm(-1) and 1350-1410 cm(-1) which are related to carbonate ions.