- https://www.cells.es/ca/actualitat/agenda/esdeveniments-publics-dalba/dynamics-of-ultrathin-v-oxide-layers-on-rh-111-and-rh-110-during-catalytic-reactions
- Dynamics of Ultrathin V-Oxide Layers on Rh(111) and Rh(110) during Catalytic Reactions
- 2017-02-22T10:00:00+01:00
- 2017-02-22T11:00:00+01:00
- Prof. R. Imbihl from Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover
- Què
- events
- Quan
-
Feb 22, 2017
de 10:00 a 11:00 (Europe/Madrid / UTC100) - On
- ALBA Synchrotron, Marie Curie Meeting room
- Nom de contacte
- Inma Hernández
- Telèfon de contacte
- 93 592 43 89
- Assistents
- If you are interested in attending, please contact Inma Hernández (ihernandez@cells.es ) with your Identity Card number and name to obtain the ALBA access.
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ABSTRACT
We use photoemission electron microscopy (PEEM) and spectroscopic LEEM to study the dynamics of ultrathin V-oxide layers supported on Rh(111) and Rh(110) surfaces during catalytic methanol oxidation in the 10-4 mbar range. The spatially uniform VOx film obtained after preparation on Rh(111) condenses under reaction conditions upon heating in a macroscopic stripe pattern which at elevated temperatures (900 – 1000 K) transform into a spot pattern of circular VOx islands of 100 – 200 µm diameter. Within a critical distance of about 100 µm the islands move towards each other and coalesce. The coalescence process can be explained by a chemical polymerization/depolymerization equilibrium in which oxygen is required to detach small V6O12 clusters from a macroscopic VOx island. On Rh(110)/VOx catalytic methanol oxidation exhibits a quite different and much more complex behavior. We observe traveling interface modulations, dendritic growth of a VOx layer and unusual chemical wave patterns including wave fragments traveling along certain crystallographic directions.
References
[1] M. Hesse et al, Phys. Rev. Lett. 115 (2015) 136102.
[2] B. von Boehn, A. Preiss, R. Imbihl, PCCP 18 (2016) 19713.
