Using recent well-defined models of γ-Al2O3 surfaces, a study was made of the interaction of single Pd atoms with γ-Al2O3 surfaces, corresponding to realistic pre-treatment conditions, by means of density functional theory periodic calculations. For relevant hydroxylation states of the surface, potential energy surfaces were determined that depicted the relationship between structure and interaction at the metal/oxide interface. This approach permitted determination of the low-energy diffusion paths of the adsorbed Pd species. Classical transition-state theory was used to derive the temperature-dependent hopping rate of Pd on γ-Al2O3 surfaces. This work provided new insights into the chemisorption and diffusion processes of single Pd atoms on alumina, and showed that the binding energy and hopping rate of Pd atoms decreased as the surface OH coverage increased. The results also offered new insights into Pd cluster formation at the initial nucleation steps on γ-Al2O3 surfaces.

Influence of the Hydroxylation of γ-Al2O3 Surfaces on the Stability and Diffusion of Single Pd Atoms - a DFT Study. M.C.Valero, P.Raybaud, P.Sautet: Journal of Physical Chemistry B, 2006, 110[4], 1759-67