Interactions of small platinum clusters with the TiC(001) surface

Density functional theory calculations are used to elucidate the interactions of small platinum clusters (Pt_n, n = 1–5) with the TiC(001) surface. The results are analyzed in terms of geometric, energetic, and electronic properties. It is found that a single Pt atom prefers to be adsorbed at the C-top site, while a Pt₂ cluster prefers dimerization and a Pt₃ cluster forms a linear structure on the TiC(001). As for the Pt₄ cluster, the three-dimensional distorted tetrahedral structure and the two-dimensional square structure almost have equal stability. In contrast with the two-dimensional isolated Pt₅ cluster, the adsorbed Pt₅ cluster prefers a three-dimensional structure on TiC(001). Substantial charge transfer takes place from TiC(001) surface to the adsorbed Pt_n clusters, resulting in the negatively charged Pt_n clusters. At last, the d-band centers of the absorbed Pt atoms and their implications in the catalytic activity are discussed