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

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

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Adsorption–desorption equilibrium investigations of n-butane on nanocrystalline sulfated zirconia thin films. / Lloyd, Rhys; Hansen, Thomas Willum; Ranke, Wolfgang; Jentoft, Friederike C.; Schlögl, Robert.

In: Applied Catalysis A - General, Vol. 391, No. 2-2, 2011, p. 215.

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

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Lloyd, Rhys; Hansen, Thomas Willum; Ranke, Wolfgang; Jentoft, Friederike C.; Schlögl, Robert / Adsorption–desorption equilibrium investigations of n-butane on nanocrystalline sulfated zirconia thin films.

In: Applied Catalysis A - General, Vol. 391, No. 2-2, 2011, p. 215.

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

Bibtex

@article{3e4a4146877f488f8cef01e336c06da1,
title = "Adsorption–desorption equilibrium investigations of n-butane on nanocrystalline sulfated zirconia thin films",
publisher = "Elsevier BV",
author = "Rhys Lloyd and Hansen, {Thomas Willum} and Wolfgang Ranke and Jentoft, {Friederike C.} and Robert Schlögl",
year = "2011",
doi = "10.1016/j.apcata.2010.06.028",
volume = "391",
number = "2-2",
pages = "215",
journal = "Applied Catalysis A - General",
issn = "0926-860X",

}

RIS

TY - JOUR

T1 - Adsorption–desorption equilibrium investigations of n-butane on nanocrystalline sulfated zirconia thin films

A1 - Lloyd,Rhys

A1 - Hansen,Thomas Willum

A1 - Ranke,Wolfgang

A1 - Jentoft,Friederike C.

A1 - Schlögl,Robert

AU - Lloyd,Rhys

AU - Hansen,Thomas Willum

AU - Ranke,Wolfgang

AU - Jentoft,Friederike C.

AU - Schlögl,Robert

PB - Elsevier BV

PY - 2011

Y1 - 2011

N2 - 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.

AB - 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.

U2 - 10.1016/j.apcata.2010.06.028

DO - 10.1016/j.apcata.2010.06.028

JO - Applied Catalysis A - General

JF - Applied Catalysis A - General

SN - 0926-860X

IS - 2-2

VL - 391

SP - 215

ER -