Martinez-Galera, A. J., Schroeder, U. A., Herbig, C., Arman, M. A., Knudsen, J. and Michely, T. (2017). Preventing sintering of nanoclusters on graphene by radical adsorption. Nanoscale, 9 (36). S. 13618 - 13630. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 2040-3372

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Abstract

Metal nanoclusters, supported on inert substrates, exhibiting well-defined shapes and sizes in a broad range of temperatures are a major object of desire in nanotechnology. Here, a technique is presented that improves the thermal stability of monodisperse and crystalline transition metal nanoclusters grown in a regular array on metal-supported graphene. To stabilize the clusters after growth under ultrahigh vacuum the system composed of the aggregates and the graphene/metal interface is exposed to radicals resulting from the dissociation of diatomic gases. As a model system we have used Pt as the metal element for cluster growth and the template consisting of the moire pattern resulting from the lattice mismatch between graphene and the Ir(111) surface. The study has been performed for deuterium and oxygen radicals, which interact very differently with graphene. Our results reveal that after radical exposure the thermally activated motion of Pt nanoclusters to adjacent moire cells and the subsequent sintering of neighbor aggregates are avoided, most pronounced for the case of atomic O. For the case of D the limits of the improvement are given by radical desorption, whereas for the case of O they are defined by an interplay between coalescence and graphene etching followed by Pt intercalation, which can be controlled by the amount of exposure. Finally, we determined the mechanism of how radical adsorption improves the thermal stability of the aggregates.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Martinez-Galera, A. J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schroeder, U. A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Herbig, C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Arman, M. A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Knudsen, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Michely, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-217354
DOI: 10.1039/c7nr04491g
Journal or Publication Title: Nanoscale
Volume: 9
Number: 36
Page Range: S. 13618 - 13630
Date: 2017
Publisher: ROYAL SOC CHEMISTRY
Place of Publication: CAMBRIDGE
ISSN: 2040-3372
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
METAL NANOPARTICLES; PT(111) SURFACE; OXYGEN; GRAPHITE; PLATINUM; MORPHOLOGY; CATALYSIS; CLUSTERS; HYDROGEN; IR(111)Multiple languages
Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, AppliedMultiple languages
Refereed: Yes
URI: http://kups.ub.uni-koeln.de/id/eprint/21735

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