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          Institute: Fritz-Haber-Institut     Collection: Inorganic Chemistry     Display Documents

ID: 424235.0, Fritz-Haber-Institut / Inorganic Chemistry
State of Transition Metal Catalysts During Carbon Nanotube Growth
Authors:Hofmann, Stephan; Blume, Raoul; Wirth, Christoph T.; Cantoro, Mirco; Sharma, Renu; Ducati, Caterina; Hävecker, Michael; Zafeiratos, Spiros; Schnörch, Peter; Oestereich, Andreas; Teschner, Detre; Albrecht, Martin; Knop-Gericke, Axel; Schlögl, Robert; Robertson, John
Research Context:Carbon in catalysis
Date of Publication (YYYY-MM-DD):2009-01-14
Title of Journal:Journal of Physical Chemistry C
Journal Abbrev.:J. Phys. Chem. C
Issue / Number:5
Start Page:1648
End Page:1656
Copyright:© 2009 American Chemical Society
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We study catalyst−support and catalyst−carbon interactions during the chemical vapor deposition of single-walled carbon nanotubes by combining environmental transmission microscopy and in situ, time-resolved X-ray photoelectron spectroscopy. We present direct evidence of what constitutes catalyst functionality by comparing the behavior of Ni, Fe, Pd, and Au model catalyst films on SiO2 during preannealing in O2 and NH3 and during C2H2 decomposition. The catalyst metal surface supplies sites to dissociate the hydrocarbon precursor and then guides the formation of a carbon lattice and the liftoff of a carbon cap. The catalysts are sharply distinguished by their reactivity toward activation of the hydrocarbon precursor, following trends known from heterogeneous catalysis. For Fe and Ni, the active state of the catalyst is a crystalline metallic nanoparticle. Graphitic networks do not form on oxidized Fe. Pd forms a silicide on SiO2 under our reducing conditions. Pd (silicides) and Au nanocrystals are catalytically less efficient in terms of precursor dissociation, while the low adhesion of C on Au surfaces impedes nanotube nucleation.
Free Keywords:CNT; SWNT; chemical vapor deposition; environmental transmission microscopy; XPS;
External Publication Status:published
Document Type:Article
Communicated by:Robert Schlögl
Affiliations:Fritz-Haber-Institut/Inorganic Chemistry/Electronic Structure and Adsorption / Metals
Fritz-Haber-Institut/Inorganic Chemistry/Inorganic Chemistry
External Affiliations:Department of Engineering, University of Cambridge, Cambridge CB3 0FA, U.K.,
IMEC, Kapeldreef 75, B-3001 Leuven, Belgium,
Arizona State University, Tempe, Arizona 85287-1704, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ, U.K.,
Institut fuer Kristallzuechtung, Max Born-Strasse 2, D-12489 Berlin, Germany
Identifiers:URL:http://dx.doi.org/10.1021/jp808560p [only for subscriber]
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