Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 86: Heterogeneous catalysis I
O 86.4: Vortrag
Donnerstag, 17. März 2011, 17:15–17:30, WIL B122
Size and Shape Changes of Pt Nanoparticles on α-Al2O3(0001) during CO Oxidation Reactions — •Uta Hejral1, Richard van Rijn2,3, Sander Roobol2, Willem Onderwaater2, Olivier Balmes3, Helena Isern3, Roberto Felici3, Joost Frenken2, and Andreas Stierle1 — 1University of Siegen, Walter-Flex-Str. 3, D-57072 Siegen, Germany — 2Kamerlingh Onnes Laboratory, Leiden University, RA Leiden 2300, The Netherlands — 3ESRF, Grenoble F-38043, France
Pt nanoparticles on aluminum oxide supports are widely used in heterogeneous catalysis and are applied successfully in reactions like the oxidation of hydrocarbons or CO. In order to achieve better catalyst efficiency, lifetime and selectivity it is important to understand catalytic processes on an atomic basis: the particle structure but also the interfacial region between particle and substrate is considered to be crucial for the catalytic properties.
To this end Pt nanoparticles were epitaxially grown on α-Al2O3(0001) substrates by means of physical vapour deposition at a substrate temperature of 500 ∘C. The particle size, shape and interfacial registry were studied in-situ during CO oxidation reactions (T=300 ∘C, pO2=10 mbar, pCO=10 mbar) by surface x-ray diffraction and x-ray reflectivity. The measurements were carried out at the ESRF ID03 beamline in a dedicated flow reactor supporting conditions from UHV to ambient pressures [1]. The x-ray investigations were completed by complementary atomic force microscopy studies.
[1] R. van Rijn, et al., Rev. Sci. Instr., 81 (2010) 014101