On the structure of bimetallic noble metal nanoparticles as revealed by aberration corrected scanning transmission electron microscopy (STEM)

In the present manuscript we present the feasibility of two different routes to obtain metal nanoparticles: (1) inert gas deposition technique (IGC) and (2) chemical routes. These two routes can enable the production of metal nanoparticles with a well-controlled size and shape distribution. In addition, Co/Au and Pd/Au nanoparticles have been deposited on three different grids with the aim of studying the coalescence of the different metals. The as-synthesized materials, that initially were forming isolated, core–shell, were sintered by thermal treatment (Co/Au) or by strong electron beam irradiation and the subsequent characterization was carried out in situ in an aberration corrected STEM.

► Bimetallic nanoparticles have been produced by a physical method and by a chemical method.
► The different structures formed by each technique have been analyzed with atomic resolution by aberration corrected transmission electron microscopy.
► The coalescence of different metal nanoparticles has been produced via thermal annealing or by electron irradiation.
► For this reaction it was found that Au was always at the core of the final product.