The adsorption of an oxygen molecule on nanoclusters of Pt and PtNi, in the size range between 13 and 55 atoms, has been studied using first-principle simulations. The structures have been obtained as a function of size and chemical composition of the clusters by means of the parallel excitable-walkers basin hopping method. O2 preferentially adsorbs along the edge between two (111) facets due to a massive distortion of the Pt-Pt bond length. This bond elongation favours the adsorption in such a way that the binding energy of oxygen on a pure 55-atom cluster is still twice the value on the clean Pt(111). On the other hand, on 55-PtshellNicore nanoparticles, the O2 binding energy is slightly lower than on Pt(111), because nickel core inhibits the stretching of the Pt-bond because of their size mismatch. However, as soon as its concentration is increased, Ni appears at the surface and its oxyphilic nature contributes to bind the oxygen molecule stronger.
Oxygen adsorption on small PtNi nanoalloys / C. Di Paola, F. Baletto. - In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS. - ISSN 1463-9076. - 13:17(2011), pp. 7701-7707. [10.1039/c0cp01662d]
|Titolo:||Oxygen adsorption on small PtNi nanoalloys|
|Settore Scientifico Disciplinare:||Settore FIS/03 - Fisica della Materia|
|Data di pubblicazione:||2011|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1039/c0cp01662d|
|Appare nelle tipologie:||01 - Articolo su periodico|