Small gold species at hydroxylated alumina surfaces. A computational study using embedded-cluster models of α-Al2O3(0001)

► With an accurate embedded-cluster density functional method, ► we explored the adsorption of gold monomers, dimers, and trimers on a α-Al2O3(0001) model surface, that is partially covered by μ1 and μ3 hydroxyl groups. ► Comparing for the first time the stability of bare (non-hydrogenated) and of hydrogenated gold clusters (by H atoms from μ3-OH) ► we found that these clusters are stable to partial oxidation. ► The calculated structural parameters of the bare forms correspond well with experimental EXAFS data on short Au-O contacts; ► yet, longer Au-O distances than in the experiment would have been expected for electron deficit gold species. ► We also calculated barriers for isomeric rearrangements of the most stable complexes.