Predicting the metal growth mode and wetting of noble metals supported on c-ZrO2

Employing periodic density-functional calculations, we predict the metal growth mode for ideal and defective interfaces of noble metals (Pd and Pt) deposited on top of cubic-ZrO2. We discuss various energetic contributions and surface textures. We propose that isolated noble metal atoms are supported on both steps and terraces on the surfaces. Pt, on the other hand, shows a higher probability to decorate steps and other low oxygen coordinated sites, while Pd forms larger metal aggregates on both high oxygen coordinated sites (terraces) as well as low oxygen coordinated sites (steps). Oxygen defects on the support act as nucleation sites for the metal cluster growth. We also investigate metal wetting of Pd and Pt on the {1 1 1} surface of cubic-zirconia. Our calculations predict that the wetting angles are ca. 110–130° for 1 and 2 mono-layers of Pd and Pt, respectively, suggesting that metal wetting decreases as the metal loading increases.