Regensburg 1998 – wissenschaftliches Programm
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O: Oberflächenphysik
O 32: Oberfl
ächenreaktionen (II)
O 32.10: Vortrag
Donnerstag, 26. März 1998, 18:30–18:45, H37
Monitoring adsorbed species during oscillatory reactions using vibrational spectroscopy — •J.H. Miners1, R. Nalezinski1, A.M. Bradshaw1, P. Gardner2, and R. Martin3 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin — 2UMIST, Manchester, UK — 3iRAS GmbH, Frankfurt/Oder
Models for the mechanisms of oscillatory reactions, such as CO oxidation or the NO+CO reaction, are usually derived indirectly, since there is little or no quantitative information available on the relative coverages of the adsorbed speicies involved. We have therefore delveloped a simple real-time method for measuring FTIR reflection-adsorption spectra of adsorbed species during any reproducibly recurring surface reaction. It involves adding FT interferograms recorded at equivalent points in sucessive oscillatory cyles. Building on our previous studies of Pt{100} + NO, CO, NO+CO and CO+NO, we have applied this method to determine the phase relationship of the C-O and N-O adsorption bands in the oscillatory CO+NO reaction on Pt{100} and to relate them to the partial pressures of the reactants and the products. The results are discussed in the light of recent kinetic models of this system.