Structural properties, magnetism and reactivity of Ni13-xFex nanoalloys

Abstract Nickel-iron nanoparticles are magnetic and reactive. Both properties depend on the relative concentration of nickel and iron, which noticeably affects certain catalytic reactions among other applications. Density Functional Theory calculations, in the generalized gradient approximation to exchange and correlation, were conducted for neutral and charged Ni 13 - x Fe x nanoalloys with the aim of obtaining, from a first principles perspective, a better understanding of how the atomic structure, chemical order, magnetic properties, and reactivity depend on the composition and charge state. The atomic and electronic structures were determined without symmetry constraints for low-energy isomers with an exhaustive scan of the structural, homotopic, and spin degrees of freedom. The relative stability was analyzed in terms of the excess energy and the second difference in energy; the global reactivity was assesed by means of DFT indicators like the electronegativity and chemical hardness; local reactivity within each nanoalloy was charcterized through the condensed Fukui functions. Finally, the first stage of oxidation is explored for the most and less reactive of the investigated nanoalloys.