title: Influence of support morphology on the bonding of molecules to nanoparticles.
abstract: Supported metal nanoparticles form the basis of heterogeneous catalysts. Above a certain nanoparticle size, it is generally assumed that adsorbates bond in an identical fashion as on a semiinfinite crystal. This assumption has allowed the database on metal single crystals accumulated over the past 40 years to be used to model heterogeneous catalysts. Using a surface science approach to CO adsorption on supported Pd nanoparticles, we show that this assumption may be flawed. Near-edge X-ray absorption fine structure measurements, isolated to one nanoparticle, show that CO bonds upright on the nanoparticle top facets as expected from single-crystal data. However, the CO lateral registry differs from the single crystal. Our calculations indicate that this is caused by the strain on the nanoparticle, induced by carpet growth across the substrate step edges. This strain also weakens the CO-metal bond, which will reduce the energy barrier for catalytic reactions, including CO oxidation.
authors.affiliation: London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1H 0AH, United Kingdom;
authors.forename: Chi Ming
authors.initials: CM
authors.lastname: Yim
authors.affiliation: London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1H 0AH, United Kingdom;
authors.forename: Chi L
authors.initials: CL
authors.lastname: Pang
authors.affiliation: Departamento de Fisica Teórica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid, Spain;
authors.forename: Diego R
authors.initials: DR
authors.lastname: Hermoso
authors.affiliation: London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1H 0AH, United Kingdom;
authors.forename: Coinneach M
authors.initials: CM
authors.lastname: Dover
authors.affiliation: School of Chemistry and Photon Science Institute, The University of Manchester, Manchester M13 9PL, United Kingdom;
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Muryn
authors.affiliation: Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, United Kingdom;
authors.forename: Francesco
authors.initials: F
authors.lastname: Maccherozzi
authors.affiliation: Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, United Kingdom;
authors.forename: Sarnjeet S
authors.initials: SS
authors.lastname: Dhesi
authors.affiliation: Departamento de Fisica Teórica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid, Spain; Condensed Matter Physics Center, Universidad Autonoma de Madrid, E-28049 Madrid, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Pérez
authors.affiliation: London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1H 0AH, United Kingdom; g.thornton@ucl.ac.uk.
authors.forename: Geoff
authors.initials: G
authors.lastname: Thornton
keywords: adsorption; carpet growth; nanoparticle; scanning tunneling microscopy; surface strain