title: Controlling Ethylene Hydrogenation Reactivity on Pt13 Clusters by Varying the Stoichiometry of the Amorphous Silica Support.
abstract: Ethylene hydrogenation was investigated on size-selected Pt13 clusters supported on three amorphous silica (a-SiO2 ) thin films with different stoichiometries. Activity measurements of the reaction at 300 K revealed that on a silicon-rich and a stoichiometric film, Pt13 exhibits a similar activity to that of Pt(111), in line with the known structure insensitivity of the reaction. On an oxygen-rich film, a threefold increased rate was measured. Pulsing ethylene at 400 K, then measuring the activity at 300 K, resulted in complete loss of activity on the silicon-rich surface compared to only marginal losses on the other surfaces. The measured reactivity trends correlate with charging characteristics of a Pt13 cluster on the SiO2 films, predicted through first-principle calculations. The results reveal that the stoichiometry-dependent charging by the support can be used to tune the selectivity of reaction pathways during a catalytic hydrogenation reaction.
authors.affiliation: Technische Universität München, Lehrstuhl für Physikalische Chemie, Zentralinstitut für Katalyseforschung und Fakultät für Chemie, Ernst-Otto-Fisher-Strasse 1 und Lichtenbergstrasse 4, 85747, Garching, Germany.|Harvard University, Department of Chemistry and Chemical Biology, 12 Oxford St., Cambridge, MA, 02138, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Crampton
authors.affiliation: Technische Universität München, Lehrstuhl für Physikalische Chemie, Zentralinstitut für Katalyseforschung und Fakultät für Chemie, Ernst-Otto-Fisher-Strasse 1 und Lichtenbergstrasse 4, 85747, Garching, Germany.
authors.forename: Marian D
authors.initials: MD
authors.lastname: Rötzer
authors.affiliation: Technische Universität München, Lehrstuhl für Physikalische Chemie, Zentralinstitut für Katalyseforschung und Fakultät für Chemie, Ernst-Otto-Fisher-Strasse 1 und Lichtenbergstrasse 4, 85747, Garching, Germany.
authors.forename: Florian F
authors.initials: FF
authors.lastname: Schweinberger
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA.
authors.forename: Bokwon
authors.initials: B
authors.lastname: Yoon
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA.
authors.forename: Uzi
authors.initials: U
authors.lastname: Landman
authors.affiliation: Technische Universität München, Lehrstuhl für Physikalische Chemie, Zentralinstitut für Katalyseforschung und Fakultät für Chemie, Ernst-Otto-Fisher-Strasse 1 und Lichtenbergstrasse 4, 85747, Garching, Germany.
authors.forename: Ueli
authors.initials: U
authors.lastname: Heiz
keywords: clusters; density functional calculations; ethylene hydrogenation; platinum; silica support stoichiometry