title: Reaction-induced cluster ripening and initial size-dependent reaction rates for CO oxidation on Pt(n)/TiO2(110)-(1×1).
abstract: We determined the CO oxidation rates for size-selected Ptn (n ∈ {3,7,10}) clusters deposited onto TiO2(110). In addition, we investigated the cluster morphologies and their mean sizes before and after the reaction. While the clusters are fairly stable upon annealing in ultrahigh vacuum up to 600 K, increasing the temperature while adsorbing either one of the two reactants leads to ripening already from 430 K on. This coarsening is even more pronounced when both reactants are dosed simultaneously, i.e., running the CO oxidation reaction. Since the ripening depends on the size initially deposited, there is nevertheless a size effect; the catalytic activity decreases monotonically with increasing initial cluster size.
authors.affiliation: Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Simon
authors.initials: S
authors.lastname: Bonanni
authors.forename: Kamel
authors.initials: K
authors.lastname: Aït-Mansour
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Harbich
authors.forename: Harald
authors.initials: H
authors.lastname: Brune