Adsorption of benzene, phenol, propane and carbonic acid molecules on oxidized Al(111) andα-Al2O3(0001) surfaces: a first-principles study

Abstract

We present the results of ab initio calculations describing the adsorption of certainsmall organic molecules on clean and oxidized Al(111) surfaces as well as on theα-Al2O3(0001) surface. Our results show that adsorption of benzene on the clean and oxidizedAl(111) surfaces is generally weak, the adsorption energy being at most around−0.5 eV per benzene molecule, and the molecule adsorbed at a considerable distance from thesurfaces. The adsorption energy varies weakly at the different adsorption sites and as afunction of the oxygen coverage. For the alumina surface, we find no benzeneadsorption at all. We have also calculated for a phenol molecule on the aluminum andalumina surfaces, since it is similar to the benzene molecule. The results show aweak adsorption for phenol on the alumina surface and no adsorption on thealuminum or oxidized aluminum surfaces at all. For the propane molecule there is noadsorption on either the oxidized aluminum or the alumina surface, whereas thecarbonic acid molecule binds strongly to the alumina but not to the aluminumsurface.