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



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ID: 429300.0, Fritz-Haber-Institut / Inorganic Chemistry
Preparation, characterization and catalytic testing of GePt catalysts
Authors:Győrffy, Nóra; Bakos, Istvan; Szabó, Sandor; Tóth, Lajos; Wild, Ute; Schlögl, Robert; Paál, Zoltan
Language:English
Research Context:Platinum in Catalysis
Date of Publication (YYYY-MM-DD):2009-04-25
Title of Journal:Journal of Catalysis
Journal Abbrev.:J. Catal.
Volume:263
Start Page:372
End Page:379
Copyright:Copyright © 2009 Published by Elsevier Inc.
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Unsupported and SiO2 supported GePt bimetallic catalysts were prepared by depositing Ge on to Pt underpotentially. Surface-sensitive cyclic voltammetry of Pt black indicated that Ge covered ca. 40–45% of the Pt surface, whereas XPS showed just 96% Pt and 4% Ge (normalized to Pt+Ge=100%). High-resolution Ge map of GePt black obtained by Energy Filtered TEM (EFTEM) showed Ge scattered in the near-surface regions. Both catalysts were tested in hexane (nH) transformation reactions between 543 and 603 K and 60 to 480 Torr H2 pressure (with 10 Torr nH), and compared with the parent Pt catalysts. GePt/SiO2 catalyst was also tested with methylcyclopentane (MCP). Adding Ge to Pt/SiO2 lowered the activity; the opposite effect was observed with GePt black. The selectivities of saturated products on bimetallic catalysts decreased, while those of hydrogenolysis products, benzene and hexenes increased in nH transformations over supported catalyst. The reverse effects were observed over the black samples where addition of Ge prevented accumulation of adventitious carbon. Ring opening was the main reaction with MCP, together with some fragments, benzene and unsaturated hydrocarbons. Ring opening of MCP became more selective with decreasing temperature and increasing hydrogen pressure. Ge on GePt black blocked contiguous Pt sites favoring the formation of coke precursors. The different catalytic behavior of GePt/SiO2 indicated somewhat different Pt–Ge interaction(s).
Free Keywords:GePt; Bimetallic catalyst; Underpotential deposition; XPS; EFTEM; Hexane isomerization; Aromatization; Methylcyclopentane ring opening
External Publication Status:published
Document Type:Article
Communicated by:Robert Schlögl
Affiliations:Fritz-Haber-Institut/Inorganic Chemistry/Inorganic Chemistry
External Affiliations:Institute of Isotopes, Hungarian Academy of Sciences, PO Box 77, Budapest, H-1525, Hungary
Institute of Material and Environmental Chemistry, HAS, PO Box 17, Budapest, H-1525, Hungary
Institute of Technical Physics and Materials Science, Hungarian Academy of Sciences, PO Box 49, Budapest, H-1525, Hungary
Identifiers:URL:http://dx.doi.org/10.1016/j.jcat.2009.02.029 [only for subscriber]
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