Low temperature and low pressure CO oxidation on gold clusters supported on MgO(100)
CRMCN (CRMCN is associated to Universities of Aix-Marseille 2 and 3.) -CNRS, Campus de Luminy, Case 913, 13288 Marseille Cedex 09, France
Corresponding author: a firstname.lastname@example.org
Published online: 13 July 2005
CO oxidation has been investigated on Au/MgO(100) model catalysts at RT and low pressure. The gold particles prepared by UHV evaporation on clean MgO surfaces are characterized by HRTEM. The gold particles are FCC single crystals or multiple twins with five-fold symmetry. Infrared spectroscopy indicates that two types of adsorption sites are present which correspond to loosely and strongly bound CO. The equilibrium CO coverage for the strongly bound CO is smaller than 0.1 ML. CO titration experiments show that oxygen does not dissociate on the gold nanoparticles. The CO oxidation reaction is studied at RT by molecular beam methods. A steady state CO reaction probability up to 0.50 is measured, for the first time at low pressure, for gold particles with a mean size of 1.5 nm. A reaction mechanism is proposed in which CO adsorbed on low coordinated gold atoms reacts with oxygen adsorbed molecularly, possibly at the Au/MgO interface.
PACS: 61.46.+w – Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 34.50.Lf – Chemical reactions, energy disposal, and angular distribution, as studied by atomic and molecular beams
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005