Atomic structure of Pt nanoclusters supported by graphene/Ir(111) and reversible transformation under CO exposure

Autor: Gilles Renaud, Sven Runte, Thomas Michely, Johann Coraux, Carsten Busse, Andreas Stierle, Dirk Franz, Timm Gerber, Uta Hejral, Peter J. Feibelman, Nils Blanc
Přispěvatelé: Deutsches Elektronen-Synchrotron [Hamburg] (DESY), CRG & Grands instruments (NEEL - CRG), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Systèmes hybrides de basse dimensionnalité (NEEL - HYBRID), Nanostructures et Rayonnement Synchrotron (NRS ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), II. Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, DESY, NanoLab, Notkestr 85, D-22607 Hamburg, Germany, CRG et Grands Instruments (CRG ), Systèmes hybrides de basse dimensionnalité (HYBRID), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Universität zu Köln
Rok vydání: 2016
Předmět:
Zdroj: Physical Review B
Physical Review B, 2016, 93 (4), pp.045426. ⟨10.1103/PhysRevB.93.045426⟩
Physical Review B, American Physical Society, 2016, 93 (4), pp.045426. ⟨10.1103/PhysRevB.93.045426⟩
Physical review / B 93(4), 045426 (2016). doi:10.1103/PhysRevB.93.045426
ISSN: 2469-9969
2469-9950
Popis: We have investigated the atomic structure of graphene/Ir(111) supported platinum clusters with on average fewer than 40 atoms by means of surface x-ray diffraction (SXRD), grazing incidence small angle x-ray scattering (GISAXS), and normal incidence x-ray standing waves (NIXSW) measurements, in comparison with density functional theory calculations (DFT). GISAXS revealed that the clusters with 1.3 nm diameter form a regular array with domain sizes of 90 nm. SXRD shows that the 1--2 monolayer high, (111) oriented Pt nanoparticles grow epitaxially on the graphene support. From the combined analysis of the SXRD and NIXSW data, a three-dimensional (3D) structural model of the clusters and the graphene support can be deduced which is in line with the DFT results. For the clusters grown in ultrahigh vacuum the lattice parameter is reduced by $(4.6\ifmmode\pm\else\textpm\fi{}0.1)%$ compared to bulk platinum. The graphene layer undergoes a strong Pt adsorption induced buckling, caused by a rehybridization of the carbon atoms below the cluster. In situ observation of the Pt clusters in CO and ${\mathrm{O}}_{2}$ environments revealed a reversible change of the clusters' strain state while successively dosing CO at room temperature and ${\mathrm{O}}_{2}$ at 575 K, pointing to a CO oxidation activity of the Pt clusters.
Databáze: OpenAIRE
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