Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 9: Surface Chemical Reactions and Heterogeneous Catalysis I
O 9.10: Vortrag
Montag, 31. März 2014, 12:45–13:00, PHY C 213
Imaging mass transfer limitations in in-situ model catalyst studies — •Sebastian Matera1, Sara Blomberg2, Max J. Hoffmann1, Johan Zetterberg2, Johan Gustafson2, Edvin Lundgren2, and Karsten Reuter1 — 1Technische Universität München, Germany — 2Lund University, Sweden
A central goal in in-situ studies of defined model catalysts is to establish a correlation between surface micro-structure and observed reactivity. In corresponding near-ambient environments this observable reactivity may be intricately influenced by macroscale heat and mass transport limitations in the reactor. We investigate such effects with a first-principles based multi-scale modeling approach integrating kinetic Monte Carlo simulations into a fluid dynamical treatment [1]. Recent methodological advances [2] allow the full consideration of the experimental reactor geometry, which we illustrate with the application to recent Planar Laser Induced Fluorescence measurements [3] of CO oxidation at Pd(100). Experiment and theory consistently reveal strong mass transfer limitations under near-ambient operation conditions. Intriguingly, the detailed comparison of calculated and measured gas-phase concentration profiles offers an unprecedented route to draw conclusions on the prevalent surface phases and reaction pathways. [1] S. Matera and K. Reuter, Catal. Lett. 133, 156 (2009); Phys. Rev. B 82, 085446 (2010); J. Catal. 295,261 (2012). [2] S. Matera, M. Maestri, A. Couci, and K. Reuter, in preparation. [3] J. Zetterberg et al., Rev. Sci. Instrum. 83, 053104 (2012)