Authors: M. Mercy, I. del Rosal, R. Poteau
Affilation: LPCNO (IRSAMC), Université de Toulouse, France
Pages: 615 - 618
Keywords: DFT, C-R activation, Ruthenium, special sites
It is now well known that size and shape of nanocatalysts affect their catalytic properties. As a consequence, nanocatalysis has recently emerged as a major new field, with experimentalists now on the edge to rationally design improved catalysts. We will show that despite the complexity of such chemical processes, theoretical chemists may contribute to this task. The key problem of nanoparticles’ selectivity regarding C-H versus C-C activation in a substrate will be addressed. Is it possible to design special sites able to favor one reaction against the other? Owing to an atomic theoretical descriptor for adsorption strength, a site with an enhanced trend to strongly adsorb chemical species has been identified on the surface of an hcp Ru55 nanocluster. An isomer of a scale model, namely Ru13, has been shaped in order to exhibit the same surface defect. Adsorption of ethane followed by σ-C-H and σ-C-C cleavages have been investigated by DFT-based NEB explorations of reaction pathways. Comparison with a defect-free cluster will also be done. These results show that this atomic descriptor is helpful to identify sites with a possible remarkable activity. Such conceptual DFT approach, followed by a mechanistic study, could participate to the rational design of nanocatalysts.