Nature of the Pt–Os Chemical Bond in Nanoalloys.

The electronic structure of Os0.5Pt0.5 bimetallic nanoalloys is studied by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The electronic population on the atoms of these alloys is determined from the obtained experimental data. It is shown that the alloy formation is accompanied by electron transfer from Os atoms to Pt atoms, while the sign and magnitude of the chemical shift are largely determined by the Madelung potential. The shape of the XPS spectra of core lines and the valence band indicate that the local density of states increases on the Os atoms near the Fermi level. Prospects of using the nanoalloys in catalytic reactions are discussed by analyzing the valence d-band parameters. [ABSTRACT FROM AUTHOR]