First-principle study of the structures, growth pattern, and properties of (Pt3Cu)n, n = 1–9, clusters

Abstract

In this work, a first-principles systematic study of (Pt3Cu)n, n = 1–9, clusters was performed employing the linear combination of Gaussian-type orbital auxiliary density functional theory approach. The growth of the clusters has been achieved by increasing the previous cluster by one Pt3Cu unit at a time. To explore in detail the potential energy surface of these clusters, initial structures were obtained from Born–Oppenheimer molecular dynamics trajectories generated at different temperatures and spin multiplicities. For each cluster size, several dozens of structures were optimized without any constraints. The most stable structures were characterized by frequency analysis calculations. This study demonstrates that the obtained most stable structures prefer low spin multiplicities. To gain insight into the growing pattern of these systems, average bond lengths were calculated for the lowest stable structures. This work reveals that the Cu atoms prefer to be together and to localize inside the cluster structures. Moreover, these systems tend to form octahedra moieties in the size range of n going from 4 to 9 Pt3Cu units. Magnetic moment per atom and spin density plots were obtained for the neutral, cationic, and anionic ground state structures. Dissociation energies, ionization potential, and electron affinity were calculated, too. The dissociation energy and the electron affinity increase as the number of Pt3Cu units grows, whereas the ionization potential decreases.

One-Pot Graphene Supported Pt3Cu Nanoparticles—From Theory towards an Effective Molecular Oxygen Reduction Reaction Catalyst

“…As already mentioned, in Figure 1 , the found lowest energy structures for the (Pt 3 Cu) n , n= 1–11 nanoclusters were presented. The structures used for this investigation were found performing a rigorous study based on molecular dynamics simulations in different electron spin multiplicities [ 20 , 21 ]. At the found optimized geometry the MEP CPs and bond paths were calculated.…”

“…These results and the employed methodology were published in Refs. [ 20 , 21 ]. These studies demonstrated that in the most stable (Pt 3 Cu) n , n = 5–6 cluster structures, the formation of structural single octahedra moieties was observed.…”

“…Moreover, the preference of Cu atoms to occupy central sites in the cluster structures and the formation of an inner smaller octahedron made by Cu atoms in the biggest (Pt 3 Cu) 11 cluster structure was also observed, suggesting that core–shell structures for this type of systems are possible and stable [ 21 ]. Additionally, in our previous theoretical investigation, spin density plots were obtained, showing that the unpaired electrons in these systems are preferentially allocated to the Pt atoms [ 20 , 21 ]. The structures of the most stable clusters together with the growing pattern that we observed for these systems are graphically illustrated in Figure 1 .…”

“…Moreover, to experimentally obtain the best possible catalyst, is important to finely tune the NP size to improve the electrochemical surface area (ECSA). In this sense, the other objective of the study is to experimentally synthesize the nanoparticles with the structures proposed in the theoretical studies as the most stable geometries for the Pt 3 Cu alloy, i.e., octahedra and twinned octahedra [ 20 , 21 ], and convert them into a fully functional ORR catalyst. To achieve this objective, a support material is required to optimize the precious metal NPs content.…”

Stability, Energetic, and Reactivity Properties of NiPd Alloy Clusters Deposited on Graphene with Defects: A Density Functional Theory Study

“…Over the last decade, bimetallic clusters or nanoparticles have received increasing attention owing to their different physical and chemical properties compared with their pure counterparts [1][2][3][4][5][6][7][8][9][10]. Due to their unique properties, these clusters can be utilized for various technological applications in the fields of catalysis, electronics, and medicine, among others [11][12][13][14].…”