Site selective adsorption and relocation of SOx in deactivation of Cu-CHA catalysts for NH3-SCR

Peter S. Hammershøi, Anita L. Godiksen, Susanne Mossin, Peter N. R. Vennestrøm, Anker D. Jensen, Ton V. W. Janssens*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The presence of SO2 in diesel exhaust gases causes severe deactivation of the Cu–CHA catalysts for the reduction of NOx by selective catalytic reduction with ammonia (NH3-SCR). The deactivation of Cu–CHA catalysts after exposure to SO2 at 550 °C for 0.5, 4, 8, 16 and 32 h, and subsequent regeneration in SO2-free gas at 550 °C was related to the site-dependent interactions of SO2 with Cu ions associated with one or two framework Al centers (Z-CuOH or Z2-Cu), as determined by electron paramagnetic resonance (EPR). SO2 primarily interacts with the EPR-silent Z-CuOH sites, but a new, EPR-active Z2-Cu phase develops with SO2 exposure time as well. A part of the original Z2-Cu species remain unaffected by SO2, which is associated with a maximum deactivation level of about 90%. Regeneration at 550 °C leads to the release of most of the SO2 from the Z-CuOH sites and some relocation of sulfur to Z2-Cu sites occurs. The activation energy for NH3-SCR on the SO2 exposed catalysts decreases with S content from about 65 kJ mol−1 to 30 kJ mol−1. For the regenerated catalysts, the activation energy is restored to about 65 kJ mol−1, showing the importance of the Z-CuOH sites for the NH3-SCR reaction.
Original languageEnglish
JournalReaction Chemistry & Engineering
Volume4
Issue number6
Pages (from-to)1081-1089
Number of pages9
ISSN2058-9883
DOIs
Publication statusPublished - 2019

Cite this

Hammershøi, Peter S. ; Godiksen, Anita L. ; Mossin, Susanne ; Vennestrøm, Peter N. R. ; Jensen, Anker D. ; Janssens, Ton V. W. / Site selective adsorption and relocation of SOx in deactivation of Cu-CHA catalysts for NH3-SCR. In: Reaction Chemistry & Engineering. 2019 ; Vol. 4, No. 6. pp. 1081-1089.
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title = "Site selective adsorption and relocation of SOx in deactivation of Cu-CHA catalysts for NH3-SCR",
abstract = "The presence of SO2 in diesel exhaust gases causes severe deactivation of the Cu–CHA catalysts for the reduction of NOx by selective catalytic reduction with ammonia (NH3-SCR). The deactivation of Cu–CHA catalysts after exposure to SO2 at 550 °C for 0.5, 4, 8, 16 and 32 h, and subsequent regeneration in SO2-free gas at 550 °C was related to the site-dependent interactions of SO2 with Cu ions associated with one or two framework Al centers (Z-CuOH or Z2-Cu), as determined by electron paramagnetic resonance (EPR). SO2 primarily interacts with the EPR-silent Z-CuOH sites, but a new, EPR-active Z2-Cu phase develops with SO2 exposure time as well. A part of the original Z2-Cu species remain unaffected by SO2, which is associated with a maximum deactivation level of about 90{\%}. Regeneration at 550 °C leads to the release of most of the SO2 from the Z-CuOH sites and some relocation of sulfur to Z2-Cu sites occurs. The activation energy for NH3-SCR on the SO2 exposed catalysts decreases with S content from about 65 kJ mol−1 to 30 kJ mol−1. For the regenerated catalysts, the activation energy is restored to about 65 kJ mol−1, showing the importance of the Z-CuOH sites for the NH3-SCR reaction.",
author = "Hammersh{\o}i, {Peter S.} and Godiksen, {Anita L.} and Susanne Mossin and Vennestr{\o}m, {Peter N. R.} and Jensen, {Anker D.} and Janssens, {Ton V. W.}",
year = "2019",
doi = "10.1039/C8RE00275D",
language = "English",
volume = "4",
pages = "1081--1089",
journal = "Reaction Chemistry & Engineering",
issn = "2058-9883",
publisher = "Royal Society of Chemistry",
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}

Site selective adsorption and relocation of SOx in deactivation of Cu-CHA catalysts for NH3-SCR. / Hammershøi, Peter S.; Godiksen, Anita L.; Mossin, Susanne; Vennestrøm, Peter N. R.; Jensen, Anker D.; Janssens, Ton V. W.

In: Reaction Chemistry & Engineering, Vol. 4, No. 6, 2019, p. 1081-1089.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Site selective adsorption and relocation of SOx in deactivation of Cu-CHA catalysts for NH3-SCR

AU - Hammershøi, Peter S.

AU - Godiksen, Anita L.

AU - Mossin, Susanne

AU - Vennestrøm, Peter N. R.

AU - Jensen, Anker D.

AU - Janssens, Ton V. W.

PY - 2019

Y1 - 2019

N2 - The presence of SO2 in diesel exhaust gases causes severe deactivation of the Cu–CHA catalysts for the reduction of NOx by selective catalytic reduction with ammonia (NH3-SCR). The deactivation of Cu–CHA catalysts after exposure to SO2 at 550 °C for 0.5, 4, 8, 16 and 32 h, and subsequent regeneration in SO2-free gas at 550 °C was related to the site-dependent interactions of SO2 with Cu ions associated with one or two framework Al centers (Z-CuOH or Z2-Cu), as determined by electron paramagnetic resonance (EPR). SO2 primarily interacts with the EPR-silent Z-CuOH sites, but a new, EPR-active Z2-Cu phase develops with SO2 exposure time as well. A part of the original Z2-Cu species remain unaffected by SO2, which is associated with a maximum deactivation level of about 90%. Regeneration at 550 °C leads to the release of most of the SO2 from the Z-CuOH sites and some relocation of sulfur to Z2-Cu sites occurs. The activation energy for NH3-SCR on the SO2 exposed catalysts decreases with S content from about 65 kJ mol−1 to 30 kJ mol−1. For the regenerated catalysts, the activation energy is restored to about 65 kJ mol−1, showing the importance of the Z-CuOH sites for the NH3-SCR reaction.

AB - The presence of SO2 in diesel exhaust gases causes severe deactivation of the Cu–CHA catalysts for the reduction of NOx by selective catalytic reduction with ammonia (NH3-SCR). The deactivation of Cu–CHA catalysts after exposure to SO2 at 550 °C for 0.5, 4, 8, 16 and 32 h, and subsequent regeneration in SO2-free gas at 550 °C was related to the site-dependent interactions of SO2 with Cu ions associated with one or two framework Al centers (Z-CuOH or Z2-Cu), as determined by electron paramagnetic resonance (EPR). SO2 primarily interacts with the EPR-silent Z-CuOH sites, but a new, EPR-active Z2-Cu phase develops with SO2 exposure time as well. A part of the original Z2-Cu species remain unaffected by SO2, which is associated with a maximum deactivation level of about 90%. Regeneration at 550 °C leads to the release of most of the SO2 from the Z-CuOH sites and some relocation of sulfur to Z2-Cu sites occurs. The activation energy for NH3-SCR on the SO2 exposed catalysts decreases with S content from about 65 kJ mol−1 to 30 kJ mol−1. For the regenerated catalysts, the activation energy is restored to about 65 kJ mol−1, showing the importance of the Z-CuOH sites for the NH3-SCR reaction.

U2 - 10.1039/C8RE00275D

DO - 10.1039/C8RE00275D

M3 - Journal article

VL - 4

SP - 1081

EP - 1089

JO - Reaction Chemistry & Engineering

JF - Reaction Chemistry & Engineering

SN - 2058-9883

IS - 6

ER -