Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO2 and Al2O3

J. L. Contreras; G. A. Fuentes; J. Navarrete; A. Vázquez; B. Zeifert; J. Salmones; L. Nuño

doi:10.1016/j.jallcom.2009.12.055

Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO₂ and Al₂O₃

J. L. Contreras, G. A. Fuentes, J. Navarrete, A. Vázquez, B. Zeifert, J. Salmones, L. Nuño

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

The effect of the Brønsted/Lewis acid ratio on isomerization of n-heptane using Al₂O₃ as a source of Lewis acidity and WOx/ZrO₂ as a source of Brønsted and Lewis acidity was studied and controlled using mechanical mixtures of these solids. These mixtures were characterized by surface area, infrared spectroscopy of pyridine, X-ray diffraction and Raman spectroscopy. It was found that the presence of W{double bond, long}O stretching mode which was consistent with the presence of oxotungstate species which were the precursors of the acid sites. It was found out that as the oxotungstate structures increased, the selectivity to n-heptane isomers increased while the hydrocracking and dehydrocyclization selectivity decreased. The presence of Brønsted acidity of the WOx/ZrO₂ domains, the increase of Knudsen diffusivity and the loss of Pt metallic area by strong interaction of the Pt with the WOx/ZrO₂ explain this catalytic behavior.

Original language	English
Pages (from-to)	466-470
Number of pages	5
Journal	Journal of Alloys and Compounds
Volume	495
Issue number	2
DOIs	https://doi.org/10.1016/j.jallcom.2009.12.055
State	Published - 16 Apr 2010
Externally published	Yes

Keywords

Catalysis
Precipitation
Surfaces
Thermal analysis

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10.1016/j.jallcom.2009.12.055

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title = "Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO2 and Al2O3",

abstract = "The effect of the Br{\o}nsted/Lewis acid ratio on isomerization of n-heptane using Al2O3 as a source of Lewis acidity and WOx/ZrO2 as a source of Br{\o}nsted and Lewis acidity was studied and controlled using mechanical mixtures of these solids. These mixtures were characterized by surface area, infrared spectroscopy of pyridine, X-ray diffraction and Raman spectroscopy. It was found that the presence of W{double bond, long}O stretching mode which was consistent with the presence of oxotungstate species which were the precursors of the acid sites. It was found out that as the oxotungstate structures increased, the selectivity to n-heptane isomers increased while the hydrocracking and dehydrocyclization selectivity decreased. The presence of Br{\o}nsted acidity of the WOx/ZrO2 domains, the increase of Knudsen diffusivity and the loss of Pt metallic area by strong interaction of the Pt with the WOx/ZrO2 explain this catalytic behavior.",

keywords = "Catalysis, Precipitation, Surfaces, Thermal analysis",

author = "Contreras, {J. L.} and Fuentes, {G. A.} and J. Navarrete and A. V{\'a}zquez and B. Zeifert and J. Salmones and L. Nu{\~n}o",

year = "2010",

month = apr,

day = "16",

doi = "10.1016/j.jallcom.2009.12.055",

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volume = "495",

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T1 - Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO2 and Al2O3

AU - Contreras, J. L.

AU - Fuentes, G. A.

AU - Navarrete, J.

AU - Vázquez, A.

AU - Zeifert, B.

AU - Salmones, J.

AU - Nuño, L.

PY - 2010/4/16

Y1 - 2010/4/16

N2 - The effect of the Brønsted/Lewis acid ratio on isomerization of n-heptane using Al2O3 as a source of Lewis acidity and WOx/ZrO2 as a source of Brønsted and Lewis acidity was studied and controlled using mechanical mixtures of these solids. These mixtures were characterized by surface area, infrared spectroscopy of pyridine, X-ray diffraction and Raman spectroscopy. It was found that the presence of W{double bond, long}O stretching mode which was consistent with the presence of oxotungstate species which were the precursors of the acid sites. It was found out that as the oxotungstate structures increased, the selectivity to n-heptane isomers increased while the hydrocracking and dehydrocyclization selectivity decreased. The presence of Brønsted acidity of the WOx/ZrO2 domains, the increase of Knudsen diffusivity and the loss of Pt metallic area by strong interaction of the Pt with the WOx/ZrO2 explain this catalytic behavior.

AB - The effect of the Brønsted/Lewis acid ratio on isomerization of n-heptane using Al2O3 as a source of Lewis acidity and WOx/ZrO2 as a source of Brønsted and Lewis acidity was studied and controlled using mechanical mixtures of these solids. These mixtures were characterized by surface area, infrared spectroscopy of pyridine, X-ray diffraction and Raman spectroscopy. It was found that the presence of W{double bond, long}O stretching mode which was consistent with the presence of oxotungstate species which were the precursors of the acid sites. It was found out that as the oxotungstate structures increased, the selectivity to n-heptane isomers increased while the hydrocracking and dehydrocyclization selectivity decreased. The presence of Brønsted acidity of the WOx/ZrO2 domains, the increase of Knudsen diffusivity and the loss of Pt metallic area by strong interaction of the Pt with the WOx/ZrO2 explain this catalytic behavior.

KW - Catalysis

KW - Precipitation

KW - Surfaces

KW - Thermal analysis

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DO - 10.1016/j.jallcom.2009.12.055

M3 - Artículo

SN - 0925-8388

VL - 495

SP - 466

EP - 470

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

IS - 2

ER -

Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO₂ and Al₂O₃

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Keywords

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