Structural and electronic changes in the Ni 13 @Ag 42 nanoparticle under surface oxidation: the role of silver coating.

Icosahedral Ni 13 @Ag 42 is a stable nanoparticle formed by a magnetic nickel core surrounded by a silver coating that provides physical protection to the 3d metal cluster as well as antibacterial properties. In this work, we report density functional theoretical calculations to delve into a comprehensive analysis of how surface oxidation impacts the structural, electronic, magnetic, and reactivity properties of this interesting nanoparticle. To elucidate the role played by the silver coating, we compare the results with those found for the bare Ni 13 cluster also subjected to surface oxidation. When Ni 13 is covered by silver, we find a markedly robust behavior of the magnetic moment of the resulting nanoparticle, which remains nearly constant upon oxidation up to the rates explored, and the same holds for its overall reactivity. The obtained trends are rationalized in terms of the complex interplay between Ni-Ag and Ag-O interactions which impact the relative inter-atomic distances, charge transfer effects, spin polarization and magnetic couplings.