In Situ Laser Raman Spectroscopy Studies of VPO Catalyst Transformations

Zhi Yang Xue; Glenn L. Schrader

doi:10.1021/jp9912713

In Situ Laser Raman Spectroscopy Studies of VPO Catalyst Transformations

Zhi Yang Xue, Glenn L. Schrader

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

80 Scopus citations

Abstract

VPO catalyst transformations were investigated using in situ laser Raman spectroscopy. During reduction -oxidation step changes, (VO)₂P₂O₇ was readily converted to α_II-, δ-VOPO₄, and ultimately to β-VOPO₄ in O₂/N₂; these V⁵⁺ phases were eliminated in n-butane/N₂. A wet N₂ feed (5-10% H₂O in N₂) transformed (VO)₂P₂O₇ and α_I-, α_II-, β-, δ-, γ-VOPO₄ to V₂O₅ at temperatures above 400°C. The presence of water vapor facilitated the loss of oxygen atoms involved in V - O - P bonding, and separated vanadium oxide and phosphorus oxide species were formed. The isolated vanadium oxide species could be transformed to V₂O₅; phosphorus species likely diffused from the catalyst lattice in the form of acid phosphates.

Original language	English (US)
Pages (from-to)	9459-9467
Number of pages	9
Journal	Journal of Physical Chemistry B
Volume	103
Issue number	44
DOIs	https://doi.org/10.1021/jp9912713
State	Published - Nov 4 1999
Externally published	Yes

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Surfaces, Coatings and Films
Materials Chemistry

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title = "In Situ Laser Raman Spectroscopy Studies of VPO Catalyst Transformations",

abstract = "VPO catalyst transformations were investigated using in situ laser Raman spectroscopy. During reduction -oxidation step changes, (VO)2P2O7 was readily converted to αII-, δ-VOPO4, and ultimately to β-VOPO4 in O2/N2; these V5+ phases were eliminated in n-butane/N2. A wet N2 feed (5-10% H2O in N2) transformed (VO)2P2O7 and αI-, αII-, β-, δ-, γ-VOPO4 to V2O5 at temperatures above 400°C. The presence of water vapor facilitated the loss of oxygen atoms involved in V - O - P bonding, and separated vanadium oxide and phosphorus oxide species were formed. The isolated vanadium oxide species could be transformed to V2O5; phosphorus species likely diffused from the catalyst lattice in the form of acid phosphates.",

author = "Xue, {Zhi Yang} and Schrader, {Glenn L.}",

year = "1999",

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doi = "10.1021/jp9912713",

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journal = "Journal of Physical Chemistry B",

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publisher = "American Chemical Society",

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T1 - In Situ Laser Raman Spectroscopy Studies of VPO Catalyst Transformations

AU - Xue, Zhi Yang

AU - Schrader, Glenn L.

PY - 1999/11/4

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N2 - VPO catalyst transformations were investigated using in situ laser Raman spectroscopy. During reduction -oxidation step changes, (VO)2P2O7 was readily converted to αII-, δ-VOPO4, and ultimately to β-VOPO4 in O2/N2; these V5+ phases were eliminated in n-butane/N2. A wet N2 feed (5-10% H2O in N2) transformed (VO)2P2O7 and αI-, αII-, β-, δ-, γ-VOPO4 to V2O5 at temperatures above 400°C. The presence of water vapor facilitated the loss of oxygen atoms involved in V - O - P bonding, and separated vanadium oxide and phosphorus oxide species were formed. The isolated vanadium oxide species could be transformed to V2O5; phosphorus species likely diffused from the catalyst lattice in the form of acid phosphates.

AB - VPO catalyst transformations were investigated using in situ laser Raman spectroscopy. During reduction -oxidation step changes, (VO)2P2O7 was readily converted to αII-, δ-VOPO4, and ultimately to β-VOPO4 in O2/N2; these V5+ phases were eliminated in n-butane/N2. A wet N2 feed (5-10% H2O in N2) transformed (VO)2P2O7 and αI-, αII-, β-, δ-, γ-VOPO4 to V2O5 at temperatures above 400°C. The presence of water vapor facilitated the loss of oxygen atoms involved in V - O - P bonding, and separated vanadium oxide and phosphorus oxide species were formed. The isolated vanadium oxide species could be transformed to V2O5; phosphorus species likely diffused from the catalyst lattice in the form of acid phosphates.

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In Situ Laser Raman Spectroscopy Studies of VPO Catalyst Transformations

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