Universität zu Köln

Franz, Dirk, Blanc, Nils, Coraux, Johann, Renaud, Gilles, Runte, Sven, Gerber, Timm, Busse, Carsten ORCID: 0000-0001-5522-0578, Michely, Thomas, Feibelman, Peter J., Hejral, Uta and Stierle, Andreas ORCID: 0000-0002-0303-6282 (2016). Atomic structure of Pt nanoclusters supported by graphene/Ir(111) and reversible transformation under CO exposure. Phys. Rev. B, 93 (4). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

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 +/- 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 O-2 environments revealed a reversible change of the clusters' strain state while successively dosing CO at room temperature and O-2 at 575 K, pointing to a CO oxidation activity of the Pt clusters.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Franz, Dirk UNSPECIFIED UNSPECIFIED UNSPECIFIED Blanc, Nils UNSPECIFIED UNSPECIFIED UNSPECIFIED Coraux, Johann UNSPECIFIED UNSPECIFIED UNSPECIFIED Renaud, Gilles UNSPECIFIED UNSPECIFIED UNSPECIFIED Runte, Sven UNSPECIFIED UNSPECIFIED UNSPECIFIED Gerber, Timm UNSPECIFIED UNSPECIFIED UNSPECIFIED Busse, Carsten UNSPECIFIED orcid.org/0000-0001-5522-0578 UNSPECIFIED Michely, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Feibelman, Peter J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hejral, Uta UNSPECIFIED UNSPECIFIED UNSPECIFIED Stierle, Andreas UNSPECIFIED orcid.org/0000-0002-0303-6282 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-286985
DOI:	10.1103/PhysRevB.93.045426
Journal or Publication Title:	Phys. Rev. B
Volume:	93
Number:	4
Date:	2016
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language METAL-SURFACES; RAY; SPECTROSCOPY; BEAMLINE; PROGRAM Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28698