Size Effect on Crystal Morphology of Faceted Face-Centered Cubic Fe Nanoparticles

Abstract

Faceted metal nanoparticles have attracted much attention owing to their size and shape enhanced unique physical and chemical properties. Here we successfully synthesized face-centered cubic (fcc) Fe nanoparticles with diverse morphologies including icosahedron, decahedron, 5-fold twinned nanorod, tetrahedron and cube. A size effect on the particle morphologies of these faceted fcc-Fe nanoparticles was revealed. Small sizes (5−13 nm) favor icosahedral nanoparticles; decahedron and 5-fold twinned nanorods are favored at intermediate sizes (12−164 nm), and triangular plate and cube at large sizes such as 200 nm. This size-morphology dependence correlation of faceted fcc-Fe nanoparticles can be well explained by thermodynamic calculations.

Direct observation of enhanced magnetism in individual size- and shape-selected 3d transition metal nanoparticles

“…For instance, in the literature Co and Ni nanoparticles were reported to exist in various structures ranging from hexagonal closed packed (hcp), primitive cubic, to face centered cubic (fcc) [27,55,56], while Fe has been stabilized in body centered cubic (bcc) and fcc at the nanoscale [48,57,58]. The RHEED data taken for as grown Fe, Co, and Ni nanoparticles are shown in Figs.…”

Probing the structure of Fe nanoparticles in multiwall carbon nanotubes grown on a stainless steel substrate

“…This theoretical indication made the iron fcc structure appealing from the point of view of potential applications. To obtain such a c-Fe phase, several attempts have been made: (i) alloying Fe with other elements such as Ni (like in stainless steel); (ii) epitaxially growing Fe ultra thin films on Cu (Shen et al 1998) or Cu/Si (Gubbiotti et al 1999) substrates; (iii) forming fcc Fe precipitates in Cu (Hines et al 2009) or Cu 1-x Au x (Klein et al 1991) matrix through heat treatments; (iv) synthesizing c-Fe nanoparticles and nanowires on a carbon film (Ling et al 2008(Ling et al , 2009); and (v) very recently embedding iron fcc nanoparticles in carbon nanotubes (CNT) (Lyubutin et al 2012). These last studies are particularly appealing because (i) it is possible to grow highly oriented CNTs, leading to anisotropic magnetic response of the device (Lyubutin et al 2012), and (ii) the surrounding CNT walls protect the metallic nanostructures from the action of ambient oxygen (Camilli et al 2011).…”

Oleylamine‐Mediated Shape Evolution of Palladium Nanocrystals

“…To better understand the morphological evolution of Pd NCs, we employed a thermodynamic model for qualitative analysis (Scheme 2). [38] The total Gibbs free energies of Pd NCs are given by Equation (1), in which, U c , U s , U e , and U t are cohesive energy, surface energy, elastic strain energy, and twin-boundary energy respectively; V, S, and T are the volume, the total {111} surface area, and the twin-boundary area respectively; E c , g 111 , W, and g t are the cohesive energy per unit volume, the {111} surface energy per unit area, the elastic strain energy density, and the twin-boundary energy per unit area respectively.…”