Computational studies of structural, energetic, and electronic properties of pure Pt and Mo and mixed Pt/Mo clusters: Comparative analysis of characteristics and trends.

The added technological potential of bimetallic clusters and nanoparticles, as compared to their pure (i.e., one-component) counterparts, stems from the ability to further fine-tune their properties and, consequently, functionalities through a simultaneous use of the "knobs" of size and composition. The practical realization of this potential can be greatly advanced by the knowledge of the correlations and relationships between the various characteristics of bimetallic nanosystems on the one hand and those of their pure counterparts as well as pure constituent components on the other hand. Here, we present results of a density functional theory based study of pure Pt and Mo clusters aimed at revisiting and exploring further their structural, electronic, and energetic properties. These are then used as a basis for analysis and characterization of the results of calculations on two-component PtMo clusters. The analysis also includes establishing relationships between the properties of the PtMo clusters and those of their Pt and Mo components. One of the particularly intriguing findings suggested by the calculated data is a linear dependence of the average binding energy per atom in sets of PtMo clusters that have the same fixed number m of Mo atoms and different number n-m of Pt atoms on the fractional content (n-m)/n of Pt atoms. We derive an analytical model that establishes the fundamental basis for this linearity and expresses its parameters-the m-dependent slope and intercept-in terms of characteristic properties of the constituent components, such as the average binding energy per atom of Mo and the average per-atom adsorption energy of the Pt atoms on Mo. The conditions of validity and degree of robustness of this model and of the linear relationship predicted by it are discussed.