Metallic nanoclusters (NCs), especially transition-metal (TM) nanoclusters (NCs) have attracted great attention due to the possibility to tune their physical and chemical properties as a function of size, composition, charge state, chemical environment, etc, which opens a wide range of possible applications such as in nanocatalysis, nanomedicine, etc, however, our atomistic understanding of the mechanisms that drive the physical and chemical properties at this regime is far from satisfactory. Thus, to contribute to this field, we have employed ab initio density functional theory within van der Waals and spin-orbit corrections combined with several algorithms (e.g., Basin Hopping Monte Carlo, Tree-growth scheme, Euclidean similarity distances, etc) to investigate TM particles, namely, 30 TMn clusters (3d, 4d, 5d, n = 1-15), 42 metals with 55-atom, numerous (PtTM)55-based nanoalloys. Beyond that, we investigate the coordination effects on different systems, e.g., CO/(PtCo)55 and Cp*/(CuAl)55, with Cp*=η5-C5Me5. We found that the general trends observed for metals in the bonds lengths and binding energies can be reproduced even using small clusters, and the properties tend to the bulk-like structures by increasing the particle size. The delocalization of the d-states contribute to yield open structures; however, an increase in the ps-d hybridization enhances the coordination, and hence, it favors icosahedron-like structures. The location of the Pt atoms within the nanoalloys depends strongly on the relative difference between the atomic radius and surface energy, i.e., atoms with smaller radius tends to be located within the core region, while atoms with smaller surface energy tend to be located on the surface region. In several cases, those mechanisms are aligned together, however, in other systems, they compete to determine the atomic distribution of the chemical species. Based on our calculations, the addition of ligands can change the atomic shape of 55-atom nanoclusters, as well as the chemical distribution in Pt-based nanoalloys. Beyond of those findings, in this talk, we will discuss further results obtained in the last years by our group.

Ab initio insights in the physical and chemical properties of bare and protected mono- and bimetallic nanoclusters: From small to nanoclusters systems (42 systems)

2019 Spring National Meeting

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