The crystalline surfaces of beta-PdH{111}: Ideal surface terminations of a stoichiometric bulk compound relevant to heterogeneous catalysis

摘要

The surface chemistry of beta-PdH{111} is of paramount importance as evidenced by the presence of the binary compound in the bulk of Pd catalytic particles during high pressure hydrogenation processes occuring at the industrial scale. Furthermore, the {111} plane is the most frequently exposed surface by the catalyst. A systematic study is herein performed which involves the computation of surface structure, workfunction, strain derivative of the surface energy, surface free energy and H binding energy for three surface terminations characterized as H-terminated, Pd-terminated and H-vacancy terminated beta-PdH{111}, by means of a plane-waves pseudopotential electronic structure algorithm. Further results of partial and local density of states, Mulliken charges and local isoelectronic softness complete a full characterization of the physical and chemical properties, which, for the first time are presented for the beta-PdH{111} surface using the predictive power of density functional theory.