Thermal Activation of Gold Atom Diffusion in Au@Pt Nanorods
Adrián Pedrazo‐Tardajos, Ece Arslan Irmak, Vished Kumar, Ana Sánchez‐Iglesias, Qiongyang Chen, Maarten Wirix, Bert Freitag, Wiebke Albrecht, Sandra Van Aert, Luis M. Liz‐Marzán, Sara Bals
Abstract
Understanding the thermal stability of bimetallic nanoparticles is of vital importance to preserve their functionalities during their use in a variety of applications. In contrast to well-studied bimetallic systems such as Au@Ag, heat-induced morphological and compositional changes in Au@Pt nanoparticles are insufficiently understood, even though Au@Pt is an important material for catalysis. To investigate the thermal instability of Au@Pt nanorods at temperatures below their bulk melting point, we combined in situ heating with two- and three-dimensional electron microscopy techniques, including three-dimensional energy-dispersive X-ray spectroscopy. The experimental results were used as input for molecular dynamics simulations, to unravel the mechanisms behind the morphological transformation of Au@Pt core-shell nanorods. We conclude that thermal stability is influenced not only by the degree of coverage of Pt on Au but also by structural details of the Pt shell.