Sulfate storage and stability on representative commercial lean NO x trap components

Nathan A. Ottinger; Todd J. Toops; Josh A. Pihl; Justin T. Roop; Jae Soon Choi; William P. Partridge

doi:10.1016/j.apcatb.2011.12.044

Sulfate storage and stability on representative commercial lean NO _x trap components

Nathan A. Ottinger, Todd J. Toops, Josh A. Pihl, Justin T. Roop, Jae Soon Choi, William P. Partridge

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

11 Scopus citations

Abstract

Components found in a commercial lean NO _x trap have been studied in order to determine their impact on sulfate storage and release. A micro-reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were used to compare components MgAl ₂O ₄, Pt/MgAl ₂O ₄, Pt/Al ₂O ₃, Pt/Ba/Al ₂O ₃, Pt/CeO ₂-ZrO ₂, and Pt/Ba/CeO ₂-ZrO ₂, as well as physical mixtures of Pt/Al ₂O ₃+MgAl ₂O ₄ and Pt/Ba/CeO ₂-ZrO ₂+MgAl ₂O ₄. Desulfation temperature profiles as well as DRIFTS NO _x and SO _x storage spectra are presented for all components. This systematic approach highlighted the ability of the underlying support to impact sulfate stability, in particular when Ba was supported on ceria-zirconia rather than alumina the desulfation temperature decreased by 60-120°C. A conceptual model of sulfation progression on the ceria-zirconia support is proposed that explains the high uptake of sulfur and low temperature release when it is employed. It was also determined that the close proximity of platinum is not necessary for much of the sulfation and desulfation chemistry that occurs, as physical mixtures with platinum dispersed on only one phase displayed similar behavior to samples with platinum dispersed on both phases.

Original language	English
Pages (from-to)	167-176
Number of pages	10
Journal	Applied Catalysis B: Environmental
Volume	117-118
DOIs	https://doi.org/10.1016/j.apcatb.2011.12.044
State	Published - May 18 2012

Funding

Research sponsored by the U.S. Department of Energy , Office of Energy Efficiency and Renewable Energy , Vehicle Technologies Program , under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

Funders	Funder number
U.S. Department of Energy
Office of Energy Efficiency and Renewable Energy	DE-AC05-00OR22725

Keywords

Ceria-zirconia
DRIFTS
Lean NO trap
MgAl O
Sulfur

Access to Document

10.1016/j.apcatb.2011.12.044

Cite this

@article{b2ab1ce1eca446ce8127c2b7f723e9b1,

title = "Sulfate storage and stability on representative commercial lean NO x trap components",

abstract = "Components found in a commercial lean NO x trap have been studied in order to determine their impact on sulfate storage and release. A micro-reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were used to compare components MgAl 2O 4, Pt/MgAl 2O 4, Pt/Al 2O 3, Pt/Ba/Al 2O 3, Pt/CeO 2-ZrO 2, and Pt/Ba/CeO 2-ZrO 2, as well as physical mixtures of Pt/Al 2O 3+MgAl 2O 4 and Pt/Ba/CeO 2-ZrO 2+MgAl 2O 4. Desulfation temperature profiles as well as DRIFTS NO x and SO x storage spectra are presented for all components. This systematic approach highlighted the ability of the underlying support to impact sulfate stability, in particular when Ba was supported on ceria-zirconia rather than alumina the desulfation temperature decreased by 60-120°C. A conceptual model of sulfation progression on the ceria-zirconia support is proposed that explains the high uptake of sulfur and low temperature release when it is employed. It was also determined that the close proximity of platinum is not necessary for much of the sulfation and desulfation chemistry that occurs, as physical mixtures with platinum dispersed on only one phase displayed similar behavior to samples with platinum dispersed on both phases.",

keywords = "Ceria-zirconia, DRIFTS, Lean NO trap, MgAl O, Sulfur",

author = "Ottinger, {Nathan A.} and Toops, {Todd J.} and Pihl, {Josh A.} and Roop, {Justin T.} and Choi, {Jae Soon} and Partridge, {William P.}",

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T1 - Sulfate storage and stability on representative commercial lean NO x trap components

AU - Ottinger, Nathan A.

AU - Toops, Todd J.

AU - Pihl, Josh A.

AU - Roop, Justin T.

AU - Choi, Jae Soon

AU - Partridge, William P.

PY - 2012/5/18

Y1 - 2012/5/18

N2 - Components found in a commercial lean NO x trap have been studied in order to determine their impact on sulfate storage and release. A micro-reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were used to compare components MgAl 2O 4, Pt/MgAl 2O 4, Pt/Al 2O 3, Pt/Ba/Al 2O 3, Pt/CeO 2-ZrO 2, and Pt/Ba/CeO 2-ZrO 2, as well as physical mixtures of Pt/Al 2O 3+MgAl 2O 4 and Pt/Ba/CeO 2-ZrO 2+MgAl 2O 4. Desulfation temperature profiles as well as DRIFTS NO x and SO x storage spectra are presented for all components. This systematic approach highlighted the ability of the underlying support to impact sulfate stability, in particular when Ba was supported on ceria-zirconia rather than alumina the desulfation temperature decreased by 60-120°C. A conceptual model of sulfation progression on the ceria-zirconia support is proposed that explains the high uptake of sulfur and low temperature release when it is employed. It was also determined that the close proximity of platinum is not necessary for much of the sulfation and desulfation chemistry that occurs, as physical mixtures with platinum dispersed on only one phase displayed similar behavior to samples with platinum dispersed on both phases.

AB - Components found in a commercial lean NO x trap have been studied in order to determine their impact on sulfate storage and release. A micro-reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were used to compare components MgAl 2O 4, Pt/MgAl 2O 4, Pt/Al 2O 3, Pt/Ba/Al 2O 3, Pt/CeO 2-ZrO 2, and Pt/Ba/CeO 2-ZrO 2, as well as physical mixtures of Pt/Al 2O 3+MgAl 2O 4 and Pt/Ba/CeO 2-ZrO 2+MgAl 2O 4. Desulfation temperature profiles as well as DRIFTS NO x and SO x storage spectra are presented for all components. This systematic approach highlighted the ability of the underlying support to impact sulfate stability, in particular when Ba was supported on ceria-zirconia rather than alumina the desulfation temperature decreased by 60-120°C. A conceptual model of sulfation progression on the ceria-zirconia support is proposed that explains the high uptake of sulfur and low temperature release when it is employed. It was also determined that the close proximity of platinum is not necessary for much of the sulfation and desulfation chemistry that occurs, as physical mixtures with platinum dispersed on only one phase displayed similar behavior to samples with platinum dispersed on both phases.

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