anticache

Prof. Konstantin M. Neyman

15.11.2018

ICREA Research Professor at Universitat de Barcelona (UB)   Location: Catalysis Research Center SR3002 Date: 15.11.2018 11:00 Uhr


Computational modelling of catalytic nanomaterials - as simple as possible, but not simpler

Konstantin Neyman

ICREA (Institució Catalana de Recerca i Estudis Avançats), 08010 Barcelona, Spain Departament de Ciència dels Materials i Química Física, Universitat de Barcelona, 08028 Barcelona, Spain

Active metal components are present in common heterogeneous catalysts as nano-aggregates of thousands of atoms. Due to their sizes, these species remain inaccessible for calculations based on density functional theory. However, such species could be rather realistically represented by computationally tractable smaller metal nano-particles, whose surface sites marginally change the reactivity with increasing particle size. We illustrate this for Pd catalysts1-3 as well as for active sites on Pt/ceria catalysts.4-6 We show that common slab models neglecting nano-effects can strongly misrepresent the surface reactivity of metal catalysts. Employed by us nanoparticle models expose a variety of active sites, whose structure and geometric flexibility notably better match those of the active sites present in catalysts under experimental conditions. Moreover, calculations of model metal particles supported on regular and nanostructured surfaces allow delineating elusive interface effects on the structure and reactivity of the catalysts. Such effects determined in our simulations will be discussed in relation with the experimental data.4,6,7

1. F. Viñes, C. Loschen, F. Illas, K.M. Neyman. Edge sites as a gate for subsurface carbon in palladium nanoparticles. J. Catal. 266 (2009) 59

2. K.M. Neyman, S. Schauermann. Hydrogen diffusion into Pd nanoparticles: Pivotal promotion by carbon. Angew. Chem. Int. Ed. 49 (2010) 4743

3. H.A. Aleksandrov, S.M. Kozlov, S. Schauermann, G.N. Vayssilov, K.M. Neyman. How absorbed hydrogen affects catalytic activity of transition metals. Angew. Chem. Int. Ed. 53 (2014) 13371

4. G.N. Vayssilov, Y. Lykhach, A. Bruix, F. Illas, V. Matolín, K.M. Neyman, J. Libuda, et al. Support nanostructure boosts oxygen transfer to catalytically active platinum nanoparticles. Nature Mater. 10 (2011) 310

5. A. Bruix, Y. Lykhach, I. Matolínová, F. Illas, V. Matolín, J. Libuda, K. M. Neyman, et al. Maximum noble metal efficiency in catalytic materials: Atomically dispersed surface platinum. Angew. Chem. Int. Ed. 53 (2014) 10525

6. Y. Lykhach, S.M. Kozlov, T. Skála, V. Johánek, A. Neitzel, J. Mysliveček, S. Fabris, V. Matolín, K.M. Neyman, J. Libuda, et al. Counting electrons on supported nanoparticles. Nature Mater. 15 (2016) 284

7. Y. Suchorski, S.M. Kozlov, K.M. Neyman, G. Rupprechter, et al. The role of metal/oxide interfaces for long-range metal particle activation during CO oxidation. Nature Mater. 17 (2018) 519

 

 


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