Adsorption–desorption equilibrium investigations of n-butane on nanocrystalline sulfated zirconia thin films

Publication: Research - peer-reviewJournal article – Annual report year: 2011

Without internal affiliation

  • Author: Lloyd, Rhys

    Fritz-Haber-Institut der Max-Planck-Gesellschaft

  • Author: Hansen, Thomas Willum

    Unknown

  • Author: Ranke, Wolfgang

    Fritz-Haber-Institut der Max-Planck-Gesellschaft

  • Author: Jentoft, Friederike C.

    Fritz-Haber-Institut der Max-Planck-Gesellschaft

  • Author: Schlögl, Robert

    Fritz-Haber-Institut der Max-Planck-Gesellschaft

View graph of relations

Nanocrystalline thin films of the alkane skeletal isomerisation catalyst sulfated zirconia were successfully deposited on a silicon substrate in order to allow the application of surface science techniques. Thermal treatment of the films was optimised to chemically mimic the powder preparation process, resulting in films possessing the essential features (including tetragonal phase, nanocrystallinity and sulfur content of ∼3 at.%) of active powder catalysts. The n-butane adsorption–desorption equilibrium under isobaric conditions (10−8–10−6 h Pa) over the temperature range 300–100 K was monitored by photoelectron spectroscopy. Analysis of the isobars revealed strong and weak n-butane chemisorption sites, releasing heats of between 59–40 and 47–34 kJ/mol, corresponding to 5 and 25% of a monolayer coverage, respectively. The total amount of chemisorbed n-butane coincides with the estimated number of surface sulfate groups. An increase in adsorption heat was observed between coverages of ∼5–8% of a monolayer, indicating adsorbate–adsorbate interactions. It follows that adjacent sites are present and isomerisation by a bimolecular surface reaction is feasible. Physisorption on the films generates heats of ∼28 kJ/mol, for coverages from 30% up to a complete monolayer. Multilayer adsorption results in the formation of an electrically insulating adsorbate structure. It is proposed that the strong chemisorption sites correspond to an interaction with a minority disulfate species.
Original languageEnglish
JournalApplied Catalysis A - General
Publication date2011
Volume391
Issue2-2
Pages215
ISSN0926-860X
DOIs
StatePublished
CitationsWeb of Science® Times Cited: 2
Download as:
Download as PDF
Select render style:
APAAuthorCBEHarvardMLAStandardVancouverShortLong
PDF
Download as HTML
Select render style:
APAAuthorCBEHarvardMLAStandardVancouverShortLong
HTML
Download as Word
Select render style:
APAAuthorCBEHarvardMLAStandardVancouverShortLong
Word

ID: 6454533