Density Functional Theory Study on the Nucleation and Growth of Pt(n) Clusters on γ-Al(2)O(3)(001) Surface

[Image: see text] Little is known about the detailed structural information at the interface of Pt(n) cluster and γ-Al(2)O(3)(001) surface, which plays an important role in the dehydrogenation and cracking of hydrocarbons. Here, the nucleation and growth of Pt(n) (n = 1–8, 13) clusters on a γ-Al(2)O(3)(001) surface have been examined using density functional theory. For the most stable configuration Pt(n)/γ-Al(2)O(3)(001) (n = 1–8, 13), Pt(n) clusters bond to the γ-Al(2)O(3)(001) surface through Pt–O and Pt–Al bonds at the expense of electron density of the Pt(n) cluster. With the increase in the Pt(n) cluster size, both the metal–support interaction and the nucleation energies exhibit an odd–even oscillation pattern, which are lower for an even Pt(n) cluster size than those for its adjacent odd ones. Both the metal–surface and metal–metal interactions are competitive, which control the nanoparticle morphology transition from two-dimension (2D) to three-dimension (3D). On the γ-Al(2)O(3)(001) surface, when the metal–support interaction governs, smaller clusters such as Pt(1), Pt(2), Pt(3), and Pt(4) prefer a planar 2D nature. Alternatively, when the metal–metal interaction dominates, larger clusters such as Pt(5), Pt(6), Pt(7), Pt(8), and Pt(13) exhibit a two-layer structure with one or more Pt atoms on the top layer not interacting directly with the support. Herein, the Pt(4) cluster is the most stable 2D structure; Pt(5) and Pt(6) clusters are the transition from the 2D to the 3D structure; and the Pt(7) cluster is the smallest 3D structure.