Bimetallic Pd–Au nanocluster arrays grown on nanostructured alumina templates

Abstract

Bimetallic nanoparticles are becoming increasingly interesting in nanoscience and nanotechnology. They have applications in, for example, catalysis and sensors, high density magnetic storage, and optical filters. However, experimentally it is relatively difficult to obtain homogeneous distributions of bimetallic nanoparticles: not only is their size distribution broad but, of greater concern, their chemical composition is generally non-uniform. For many applications, it is also important that the nanoparticles order in a regular array. Here, we present a new method that allows the generation of a regular two-dimensional array of bimetallic Au–Pd nanoparticles with tunable size and composition. The method provides a unique model for studying size and composition effects in the physical and chemical properties of bimetallic nanoparticles.

A versatile fabrication method for cluster superlattices

“…High cohesive energy metals mostly form rather perfect cluster superlattices, tested here for Ir, Pt and W. It is thus natural to apply cluster seeding, i.e. to define the positions of the clusters by a small of a high cohesive energy metal and to grow these seeds by subsequent deposition of a low cohesive energy metal [11,12]. The successful application of this method is visualized in figure 5.…”

“…Alumina double layers on Ni 3 Al(111) exhibit a phase with a regular superlattice of sites for nucleation upon metal deposition [10], which are holes in the oxide [11]. Cluster superlattices were realized for a variety of metals at room temperature [10,12,13] and a high perfection was achieved for Pd [10]. Although such cluster 3 lattices appear to be suited as model catalysts, the preparation of the alumina layer is the result of a subtle procedure, comprises defects and at least two phases of alumina with limited domain sizes, of which only one is suitable as a template [11].…”

Interlayer exchange coupling in ordered Fe nanocluster arrays grown onAl2O3/Ni3Al(111)

“…Amongst the transition metal elements investigated so far, Pd is the only one diffusing into the corner holes [14,16]. Therefore it has been used as seed to nucleate other transition metal elements leading to well ordered arrays of quasibimetallic nanoparticles of AuPd [17], FePd and CoPd [14,18], and NiPd [19].…”

TEM studies of stress relaxation in catalytic Au-Pd core-shell nanoparticles

“…This paper examines Au-Pd core-shell nanoparticles (CS-NPs). These have been widely studied by several research groups [1][2][3][4] in terms of fabrication, stabilization and catalytic behaviour, but the factors controlling catalytic behaviour, in particular the relative contribution of lattice strain and ligand (electronic) effects, remain unclear. Here, we examine the strain and morphology in Au-Pd CS-NPs as a function of the Pd thickness.…”