New operando method for quantifying the relative half-cycle rates of the NO SCR redox cycle over Cu-exchanged zeolites

W. P. Partridge; S. Y. Joshi; J. A. Pihl; N. W. Currier

doi:10.1016/j.apcatb.2018.04.071

New operando method for quantifying the relative half-cycle rates of the NO SCR redox cycle over Cu-exchanged zeolites

W. P. Partridge, S. Y. Joshi, J. A. Pihl, N. W. Currier

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

30 Scopus citations

Abstract

An operando experimental method for monitoring relative variations in half-cycle rates of the Cu redox-cycle model of selective-catalytic-reduction (SCR) is demonstrated, along with a kinetic model for predicting the same. Conversion inflections (CI) can occur at SCR onset within Cu/SCR catalysts; transient CI involves initial conversion growth to an intermediate value greater than exists at steady state (SS) before degrading to the SS value. While similar CI has been reported for Fe/SCR catalysts as being due to NH₃ inhibition, Cu/SCR CI is inconsistent with a similar origin. Rather, Cu/SCR CI is due to imbalances in the redox-half-cycle rates, and will occur when reduction is faster than oxidation. The temporal CI shape varies with the redox-cycle kinetic parameters and model formulation, and can be used to study the same. We demonstrate the first measurements of dynamic half-cycle rate balancing at SCR onset, use CI and onset transients to study variations in half-cycle rates under Standard, Fast and NO₂ SCR, and present the first redox-cycle model showing CI. The new operando method and model provides a basis for better understanding the SCR redox process, and determining the individual half-cycles kinetic model formulation and parameters.

Original language	English
Pages (from-to)	195-204
Number of pages	10
Journal	Applied Catalysis B: Environmental
Volume	236
DOIs	https://doi.org/10.1016/j.apcatb.2018.04.071
State	Published - Nov 15 2018

Funding

This work was performed in a cooperative research and development agreement (CRADA) between Oak Ridge National Laboratory and Cummins Inc., and sponsored by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Vehicle Technology Office , program managers/sponsors Gurpreet Singh and Ken Howden. Notice: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for the United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). Appendix A

Keywords

Cu redox half cycles
Kinetic model
NHSCR
Operando SpaciMS

Access to Document

10.1016/j.apcatb.2018.04.071

Cite this

@article{5ed89785c5914dda9be85def120d59a1,

title = "New operando method for quantifying the relative half-cycle rates of the NO SCR redox cycle over Cu-exchanged zeolites",

abstract = "An operando experimental method for monitoring relative variations in half-cycle rates of the Cu redox-cycle model of selective-catalytic-reduction (SCR) is demonstrated, along with a kinetic model for predicting the same. Conversion inflections (CI) can occur at SCR onset within Cu/SCR catalysts; transient CI involves initial conversion growth to an intermediate value greater than exists at steady state (SS) before degrading to the SS value. While similar CI has been reported for Fe/SCR catalysts as being due to NH3 inhibition, Cu/SCR CI is inconsistent with a similar origin. Rather, Cu/SCR CI is due to imbalances in the redox-half-cycle rates, and will occur when reduction is faster than oxidation. The temporal CI shape varies with the redox-cycle kinetic parameters and model formulation, and can be used to study the same. We demonstrate the first measurements of dynamic half-cycle rate balancing at SCR onset, use CI and onset transients to study variations in half-cycle rates under Standard, Fast and NO2 SCR, and present the first redox-cycle model showing CI. The new operando method and model provides a basis for better understanding the SCR redox process, and determining the individual half-cycles kinetic model formulation and parameters.",

keywords = "Cu redox half cycles, Kinetic model, NHSCR, Operando SpaciMS",

author = "Partridge, {W. P.} and Joshi, {S. Y.} and Pihl, {J. A.} and Currier, {N. W.}",

note = "Publisher Copyright: {\textcopyright} 2018 Elsevier B.V.",

year = "2018",

month = nov,

day = "15",

doi = "10.1016/j.apcatb.2018.04.071",

language = "English",

volume = "236",

pages = "195--204",

journal = "Applied Catalysis B: Environmental",

issn = "0926-3373",

publisher = "Elsevier",

}

TY - JOUR

T1 - New operando method for quantifying the relative half-cycle rates of the NO SCR redox cycle over Cu-exchanged zeolites

AU - Partridge, W. P.

AU - Joshi, S. Y.

AU - Pihl, J. A.

AU - Currier, N. W.

PY - 2018/11/15

Y1 - 2018/11/15

N2 - An operando experimental method for monitoring relative variations in half-cycle rates of the Cu redox-cycle model of selective-catalytic-reduction (SCR) is demonstrated, along with a kinetic model for predicting the same. Conversion inflections (CI) can occur at SCR onset within Cu/SCR catalysts; transient CI involves initial conversion growth to an intermediate value greater than exists at steady state (SS) before degrading to the SS value. While similar CI has been reported for Fe/SCR catalysts as being due to NH3 inhibition, Cu/SCR CI is inconsistent with a similar origin. Rather, Cu/SCR CI is due to imbalances in the redox-half-cycle rates, and will occur when reduction is faster than oxidation. The temporal CI shape varies with the redox-cycle kinetic parameters and model formulation, and can be used to study the same. We demonstrate the first measurements of dynamic half-cycle rate balancing at SCR onset, use CI and onset transients to study variations in half-cycle rates under Standard, Fast and NO2 SCR, and present the first redox-cycle model showing CI. The new operando method and model provides a basis for better understanding the SCR redox process, and determining the individual half-cycles kinetic model formulation and parameters.

AB - An operando experimental method for monitoring relative variations in half-cycle rates of the Cu redox-cycle model of selective-catalytic-reduction (SCR) is demonstrated, along with a kinetic model for predicting the same. Conversion inflections (CI) can occur at SCR onset within Cu/SCR catalysts; transient CI involves initial conversion growth to an intermediate value greater than exists at steady state (SS) before degrading to the SS value. While similar CI has been reported for Fe/SCR catalysts as being due to NH3 inhibition, Cu/SCR CI is inconsistent with a similar origin. Rather, Cu/SCR CI is due to imbalances in the redox-half-cycle rates, and will occur when reduction is faster than oxidation. The temporal CI shape varies with the redox-cycle kinetic parameters and model formulation, and can be used to study the same. We demonstrate the first measurements of dynamic half-cycle rate balancing at SCR onset, use CI and onset transients to study variations in half-cycle rates under Standard, Fast and NO2 SCR, and present the first redox-cycle model showing CI. The new operando method and model provides a basis for better understanding the SCR redox process, and determining the individual half-cycles kinetic model formulation and parameters.

KW - Cu redox half cycles

KW - Kinetic model

KW - NHSCR

KW - Operando SpaciMS

UR - http://www.scopus.com/inward/record.url?scp=85046751259&partnerID=8YFLogxK

U2 - 10.1016/j.apcatb.2018.04.071

DO - 10.1016/j.apcatb.2018.04.071

M3 - Article

AN - SCOPUS:85046751259

SN - 0926-3373

VL - 236

SP - 195

EP - 204

JO - Applied Catalysis B: Environmental

JF - Applied Catalysis B: Environmental

ER -

New operando method for quantifying the relative half-cycle rates of the NO SCR redox cycle over Cu-exchanged zeolites

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this