A redox model for NO oxidation, NH3 oxidation and high temperature standard SCR over Cu-SSZ-13

Rohil Daya; Dhruba J. Deka; Anshuman Goswami; Unmesh Menon; Dylan Trandal; William P. Partridge; Saurabh Y. Joshi

doi:10.1016/j.apcatb.2023.122524

A redox model for NO oxidation, NH₃ oxidation and high temperature standard SCR over Cu-SSZ-13

Rohil Daya, Dhruba J. Deka, Anshuman Goswami, Unmesh Menon, Dylan Trandal, William P. Partridge, Saurabh Y. Joshi

Applied Catalysis&Emissions Res. Group

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

11 Scopus citations

Abstract

A kinetic model is developed to predict the influence of temperature and hydrothermal aging on the redox of active Cu sites under standard SCR, NO oxidation and NH₃ oxidation conditions over a practically relevant fully-formulated Cu-SSZ-13 catalyst. NO₂/N₂ production during NO/NH₃ titration of Cu^II sites is utilized to identify rate parameters associated with NO-only RHC (reduction half cycle) and NH₃-only RHC respectively. Integral N₂ formation during subsequent NO + NH₃ titration is consistent with the production of one NO₂ per two Cu^II sites reduced during NO-only RHC and one N₂ per six Cu^II sites reduced during NH₃-only RHC. Decreased reduction of Cu^II sites by NO/NH₃ upon hydrothermal aging, along with the production of one NO₂ per two Cu^II sites during NO-only RHC, is accordant with the involvement of proximal ZCuOH and oxygen-bridged dimeric Cu^II sites. Oxidation of partially solvated and framework coordinated ZCu (Cu^I) sites occurs in presence of O₂, does not produce N₂ and can lead to the consumption of Brønsted acid sites. A global OHC kinetic model is developed to predict transient and integral N₂ formation during exposure of Cu^I sites to a mixture of NO and O₂. The resulting redox kinetic model quantitatively predicts NO and NH₃ consumption during isothermal transient response Cu redox (TRCR) protocols, along with temperature and age dependent steady-state standard SCR and oxidation conditions. The redox model presented in this work synthesizes recent kinetic, spectroscopic and computational findings to provide a foundational description of active site redox during standard SCR, NO oxidation and NH₃ oxidation over Cu-SSZ-13.

Original language	English
Article number	122524
Journal	Applied Catalysis B: Environmental
Volume	328
DOIs	https://doi.org/10.1016/j.apcatb.2023.122524
State	Published - Jul 5 2023

Funding

This research was supported in part by the DOE Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) and used resources at the National Transportation Research Center, a DOE-EERE User Facility at Oak Ridge National Laboratory (ORNL). We thank Neal Currier, Michael Cunningham, Krishna Kamasamudram and Aleksey Yezerets from Cummins Inc. for their valuable support and promotion of the ORNL-Cummins Catalyst CRADA (cooperative research and development agreement) partnership (No. 97-0489) within which a portion of this work was performed, and their SCR-catalyst insights. We thank Josh Pihl, group leader of the ORNL Applied Catalysis and Emissions Research Group, for his critical review and suggestions regarding catalysis methods and experiments, and help with experimental system automation. We thank DOE VTO Program & Technology Managers: Gurpeet Singh, Siddiq Khan, and Ken Howden for supporting the CRADA project. This research was supported in part by the DOE Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) and used resources at the National Transportation Research Center, a DOE-EERE User Facility at Oak Ridge National Laboratory (ORNL). We thank Neal Currier, Michael Cunningham, Krishna Kamasamudram and Aleksey Yezerets from Cummins Inc. for their valuable support and promotion of the ORNL-Cummins Catalyst CRADA (cooperative research and development agreement) partnership (No. 97-0489) within which a portion of this work was performed, and their SCR-catalyst insights. We thank Josh Pihl, group leader of the ORNL Applied Catalysis and Emissions Research Group, for his critical review and suggestions regarding catalysis methods and experiments, and help with experimental system automation. We thank DOE VTO Program & Technology Managers: Gurpeet Singh, Siddiq Khan, and Ken Howden for supporting the CRADA project. Supporting Information includes additional model validation with measured transient and integral N2 over the ten-step TRCR protocol. Turnover rates, CuII fraction and NH3 storage predictions during this protocol from 200 °C to 450 °C are also provided. Redox model validation with transient and steady-state NO/NH3 consumption during TRCR protocols and the four-step protocol is shown, along with corresponding model predictions of mean surface coverage and overall reaction rates as a function of time and temperature.

Keywords

Brønsted acid sites
Cu-zeolites
Hydrothermal aging
Kinetic model
Selective catalytic reduction

Access to Document

10.1016/j.apcatb.2023.122524

Cite this

@article{ee8bda33e29e4fbe83c0c3b094e86e8f,

title = "A redox model for NO oxidation, NH3 oxidation and high temperature standard SCR over Cu-SSZ-13",

abstract = "A kinetic model is developed to predict the influence of temperature and hydrothermal aging on the redox of active Cu sites under standard SCR, NO oxidation and NH3 oxidation conditions over a practically relevant fully-formulated Cu-SSZ-13 catalyst. NO2/N2 production during NO/NH3 titration of CuII sites is utilized to identify rate parameters associated with NO-only RHC (reduction half cycle) and NH3-only RHC respectively. Integral N2 formation during subsequent NO + NH3 titration is consistent with the production of one NO2 per two CuII sites reduced during NO-only RHC and one N2 per six CuII sites reduced during NH3-only RHC. Decreased reduction of CuII sites by NO/NH3 upon hydrothermal aging, along with the production of one NO2 per two CuII sites during NO-only RHC, is accordant with the involvement of proximal ZCuOH and oxygen-bridged dimeric CuII sites. Oxidation of partially solvated and framework coordinated ZCu (CuI) sites occurs in presence of O2, does not produce N2 and can lead to the consumption of Br{\o}nsted acid sites. A global OHC kinetic model is developed to predict transient and integral N2 formation during exposure of CuI sites to a mixture of NO and O2. The resulting redox kinetic model quantitatively predicts NO and NH3 consumption during isothermal transient response Cu redox (TRCR) protocols, along with temperature and age dependent steady-state standard SCR and oxidation conditions. The redox model presented in this work synthesizes recent kinetic, spectroscopic and computational findings to provide a foundational description of active site redox during standard SCR, NO oxidation and NH3 oxidation over Cu-SSZ-13.",

keywords = "Br{\o}nsted acid sites, Cu-zeolites, Hydrothermal aging, Kinetic model, Selective catalytic reduction",

author = "Rohil Daya and Deka, {Dhruba J.} and Anshuman Goswami and Unmesh Menon and Dylan Trandal and Partridge, {William P.} and Joshi, {Saurabh Y.}",

note = "Publisher Copyright: {\textcopyright} 2023 Elsevier B.V.",

year = "2023",

month = jul,

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doi = "10.1016/j.apcatb.2023.122524",

language = "English",

volume = "328",

journal = "Applied Catalysis B: Environmental",

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T1 - A redox model for NO oxidation, NH3 oxidation and high temperature standard SCR over Cu-SSZ-13

AU - Daya, Rohil

AU - Deka, Dhruba J.

AU - Goswami, Anshuman

AU - Menon, Unmesh

AU - Trandal, Dylan

AU - Partridge, William P.

AU - Joshi, Saurabh Y.

PY - 2023/7/5

Y1 - 2023/7/5

N2 - A kinetic model is developed to predict the influence of temperature and hydrothermal aging on the redox of active Cu sites under standard SCR, NO oxidation and NH3 oxidation conditions over a practically relevant fully-formulated Cu-SSZ-13 catalyst. NO2/N2 production during NO/NH3 titration of CuII sites is utilized to identify rate parameters associated with NO-only RHC (reduction half cycle) and NH3-only RHC respectively. Integral N2 formation during subsequent NO + NH3 titration is consistent with the production of one NO2 per two CuII sites reduced during NO-only RHC and one N2 per six CuII sites reduced during NH3-only RHC. Decreased reduction of CuII sites by NO/NH3 upon hydrothermal aging, along with the production of one NO2 per two CuII sites during NO-only RHC, is accordant with the involvement of proximal ZCuOH and oxygen-bridged dimeric CuII sites. Oxidation of partially solvated and framework coordinated ZCu (CuI) sites occurs in presence of O2, does not produce N2 and can lead to the consumption of Brønsted acid sites. A global OHC kinetic model is developed to predict transient and integral N2 formation during exposure of CuI sites to a mixture of NO and O2. The resulting redox kinetic model quantitatively predicts NO and NH3 consumption during isothermal transient response Cu redox (TRCR) protocols, along with temperature and age dependent steady-state standard SCR and oxidation conditions. The redox model presented in this work synthesizes recent kinetic, spectroscopic and computational findings to provide a foundational description of active site redox during standard SCR, NO oxidation and NH3 oxidation over Cu-SSZ-13.

AB - A kinetic model is developed to predict the influence of temperature and hydrothermal aging on the redox of active Cu sites under standard SCR, NO oxidation and NH3 oxidation conditions over a practically relevant fully-formulated Cu-SSZ-13 catalyst. NO2/N2 production during NO/NH3 titration of CuII sites is utilized to identify rate parameters associated with NO-only RHC (reduction half cycle) and NH3-only RHC respectively. Integral N2 formation during subsequent NO + NH3 titration is consistent with the production of one NO2 per two CuII sites reduced during NO-only RHC and one N2 per six CuII sites reduced during NH3-only RHC. Decreased reduction of CuII sites by NO/NH3 upon hydrothermal aging, along with the production of one NO2 per two CuII sites during NO-only RHC, is accordant with the involvement of proximal ZCuOH and oxygen-bridged dimeric CuII sites. Oxidation of partially solvated and framework coordinated ZCu (CuI) sites occurs in presence of O2, does not produce N2 and can lead to the consumption of Brønsted acid sites. A global OHC kinetic model is developed to predict transient and integral N2 formation during exposure of CuI sites to a mixture of NO and O2. The resulting redox kinetic model quantitatively predicts NO and NH3 consumption during isothermal transient response Cu redox (TRCR) protocols, along with temperature and age dependent steady-state standard SCR and oxidation conditions. The redox model presented in this work synthesizes recent kinetic, spectroscopic and computational findings to provide a foundational description of active site redox during standard SCR, NO oxidation and NH3 oxidation over Cu-SSZ-13.

KW - Brønsted acid sites

KW - Cu-zeolites

KW - Hydrothermal aging

KW - Kinetic model

KW - Selective catalytic reduction

UR - http://www.scopus.com/inward/record.url?scp=85149271365&partnerID=8YFLogxK

U2 - 10.1016/j.apcatb.2023.122524

DO - 10.1016/j.apcatb.2023.122524

M3 - Article

AN - SCOPUS:85149271365

SN - 0926-3373

VL - 328

JO - Applied Catalysis B: Environmental

JF - Applied Catalysis B: Environmental

M1 - 122524

ER -