Dresden 2003 – wissenschaftliches Programm

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SYCN: Computational nanoscience - from materials to biology

SYCN 102: Computational Nanoscience: From Materials to Biology (Poster, gemeinsam mit SYSE)

SYCN 102.16: Poster

Dienstag, 25. März 2003, 19:00–21:00, ZEU/160

First-principles study of Cu nanoclusters adorbed on nonpolar ZnO (1010) surfaces — •Bernd Meyer and Dominik Marx — Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, D-44780 Bochum, Germany

Copper on ZnO is a widely used catalyst for the synthesis of methanol from H₂ and CO/CO₂. Although pure ZnO is already a good catalyst for hydrogenation and dehydrogenation reactions, only the combination with small Cu particles makes it the highly active and selective catalyst that is employed on an industrial scale.

So far, the atomistic and electronic structure of the Cu particles on the ZnO surfaces and the underlying mechanism for the enhanced catalytic properties are widely unknown. To study the interesting interplay between the ZnO substrate and the Cu clusters, we use density-functional theory based calculations to determine the atomistic and electronic structure of such systems. As a first step we have determined the equilibrium structures and adsorption energies of small Cu clusters of two to eight atoms on the nonpolar ZnO (1010) surface. Molecular-dynamics simulations and “simulated annealing” were used to search for structures representing global energy minima. We find that already for very small cluster sizes the Cu–Cu cohesive energy is much larger than the adorption energy on the ZnO substrate. Therefore, usually cluster geometries very similar to isolated clusters in vacuum are found.