Theoretical study of the icosahedral to cuboctahedral structural transition in Rh and Pd clusters

First-Principles Study on Stability and Electronic Structures of Pt-Rh Bimetallic Nanoparticles

“…Recent first-principles-based investigation by the authors elucidate that Pt-Rh stable surface significantly destabilize CO adsorption with respect to hydrogen, which indicates the Pt-Rh surface to be potential candidate for electrode in polymer electrolyte fuel cells (PEFC): The destabilization is reasonably attributed to the d-state electronic contribution of top-layer Pt atoms, particularly to the d-band center measured from the Fermi energy. DFT-based studies on Pt and Rh nanoparticles have also been carried out to understand stable atomic configurations: [30][31][32][33][34][35][36] Up to now, nanoparticles consisting of $ 300 atoms are extensively studied, and a number of stable or metastable structures including icosahedron, octahedron, cuboctahedron, biplanar, and lower-symmetry shapes are proposed, where their relative stability is still under discussion. Particularly, icosahedral and cubohedral Pt and Rh nanoparticles have been considered interesting since they are Platonic and Archimedean solids in uniform polyhedra, and they are linked to each other by Mackay transformation with small energy difference.…”

“…Particularly, icosahedral and cubohedral Pt and Rh nanoparticles have been considered interesting since they are Platonic and Archimedean solids in uniform polyhedra, and they are linked to each other by Mackay transformation with small energy difference. 31) In contrast to such stimulating experimental as well as theoretical investigations for Pt, Rh and Pt-Rh nanoparticles and bulk surfaces, theoretical studies on the Pt-Rh nanoparticle is somehow confined to segregation profile predicted by empirical method including pair-bond energy model 37) and free energy concentration expansion: 38) These studies predict Pt atoms energetically prefer to segregating to the surface rather than subsurfaces. With these considerations, further theoretical assessment for electronic structure and catalytic properties of the Pt-Rh nanoparticles based on firstprinciples calculation is highly desirable in order to design suitable alloy nanoparticles.…”

Entropic Effects on the Size Dependence of Cluster Structure

“…At other temperatures, however, the structure with lowest free energy needs to be found. However, perhaps through an expectation that entropic effects are unlikely to be important or are too complicated to take into account, size is usually the only variable that is considered both experimentally [10,11,12] and theoretically [2,3,4,5,6,7,8].In this paper we consider the role that entropy plays in the size evolution of cluster structure, and show that temperature can be a key variable in determining the equi- [14]. These clusters have the optimal shape for the three main types of regular packing seen in clusters: face-centred cubic, icosahedral and decahedral, respectively.…”

“…At other temperatures, however, the structure with lowest free energy needs to be found. However, perhaps through an expectation that entropic effects are unlikely to be important or are too complicated to take into account, size is usually the only variable that is considered both experimentally [10,11,12] and theoretically [2,3,4,5,6,7,8].…”

Stability and Electronic Structures of Pt-Rh Icosahedral Nanoparticles

“…[30][31][32][33][34][35][36] Up to now, nanoparticles consisting of $300 atoms are extensively studied, and a number of stable or metastable structures including icosahedron, octahedron, cuboctahedron, biplanar, and lower-symmetry shapes are proposed, while their relative stability is still under discussion.…”