Dresden 2011 – wissenschaftliches Programm

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KR: Fachgruppe Kristallographie

KR 7: Crystallography in Materials Science (jointly with DF)

KR 7.6: Vortrag

Donnerstag, 17. März 2011, 16:30–16:45, HSZ 101

Modeling the environment-controlled morphology changes of adsorbed two-component nanoparticles — •Sibylle Gemming¹, Gintautas Abrasonis¹, and Matthias Krause^{1, 2} — ¹Helmholtz-Zentrum Dresden-Rossendorf, PF 510119, D-01314 Dresden, Germany. — ²Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany.

The morphology and the local composition of binary nano-particles from two immiscible components are driven by the local interactions at the different interfaces within the material system. Especially in small nano-particles, atoms at interfaces cover a large part of the total amount of atoms. Therefore, the interface energetics crucially influences the relative stabilities of different possible atom arrangements both at the surface of the particles and at the interface with the support. Such a complex system can be mapped to a two-component phase-field model with a set of complex boundary conditions at the interfaces of the particle with the support and with the surrounding atmosphere. Numerical simulations have been performed to describe the morphology evolution of such particles in dependence on the external physical conditions. The results rationalize recent observations on the structural changes of oxide-supported bimetallic nano-particles cycled in oxidizing and reducing atmospheres. Funding via the ECEMP project D1 (EU-EFRE) is gratefully acknowledged.