Deactivation trends of Pd/SSZ-13 under the simultaneous presence of NO, CO, hydrocarbons and water for passive NOx adsorption

Pranaw Kunal; Todd J. Toops; Michelle K. Kidder; Michael J. Lance

doi:10.1016/j.apcatb.2021.120591

Deactivation trends of Pd/SSZ-13 under the simultaneous presence of NO, CO, hydrocarbons and water for passive NOx adsorption

Pranaw Kunal, Todd J. Toops, Michelle K. Kidder, Michael J. Lance

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

21 Scopus citations

Abstract

Pd-functionalized chabazite (Pd/SSZ-13) was evaluated for passive NOx adsorption (PNA) using low temperature combustion with diesel (LTC-D) reaction feed of the “United States Driving Research and Innovation for Vehicle efficiency and Energy sustainability” (U.S.DRIVE) protocol. Notably as per the protocol conditions, 12 % O₂ + 6 % CO₂ + 6 % H₂O was flown in all cases. NO-uptake studies in the presence of the LTC-D feed showed a systematic decline with (NO:Pd)_molar changing from 0.5 to 0.4 after 10 trials. Control experiments showed more pronounced decline for NO + CO case, with appreciable intial (NO:Pd)_molar value of 0.4, yet comparable-to-the-LTC-D-feed decline after 8 trials. CO-induced particle formation and larger extent of particle sintering was also evident from TEM analysis. Other controls did not exhibit trial-dependent deactivation as (NO:Pd)_molar values were similar between trials, at 0.3, 0.2, 0.5 and 0.2 for NO, NO+H₂, NO + unsaturated hydrocarbon (C₂H₄, C₃H₆) and NO + saturated HC (C₃H₈, C₁₀H₂₂) feeds respectively. In addition to these quantitative differences, desorption behaviors are qualitatively different. While only one major desorption event was observed for the full LTC-D feed, NO + CO and NO + unsaturated HC-controls, desorption occured in two distinct stages for NO, NO + saturated HCs and initial-NO+H₂ trials. This arises due to inherent differences in Pd sites while exposed to these chemically distinct feeds. The presence of CO and unsaturated HCs in the feed resulted in almost complete elimination of lower, sub-200 °C desorption peak. The higher temperature desorption peaks, at > 300 °C is associated with NO strongly bound to ionic Pd sites and are prevalent under reducing conditions. Using DRIFTS also, three complexes leading to PNA are assigned, [O[dbnd]N–Pd²⁺(OH)–Z], [O[dbnd]N–Pd²⁺(Z₂)] and [O[dbnd]N–Pd²⁺(H₂O)_y–Z] with the latter being clearly observed upon water exposure. Pd/SSZ-13 showed higher hydrocarbon trapping than the SSZ-13 counterpart.

Original language	English
Article number	120591
Journal	Applied Catalysis B: Environmental
Volume	299
DOIs	https://doi.org/10.1016/j.apcatb.2021.120591
State	Published - Dec 15 2021

Funding

Funding was provided by the U.S. Department of Energy's Vehicle Technologies Office (VTO). The authors greatly appreciate support from Ken Howden, Siddiq Khan, and Gurpreet Singh at VTO. Access to the FEI Talos F200X STEM was provided by the Department of Energy, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. Funding was provided by the U.S. Department of Energy’s Vehicle Technologies Office (VTO) . The authors greatly appreciate support from Ken Howden, Siddiq Khan, and Gurpreet Singh at VTO. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE 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 ).

Keywords

Ion-exchange
Low-temperature emission control
Palladium
Passive NOx adsorption
SSZ-13
USDRIVE

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title = "Deactivation trends of Pd/SSZ-13 under the simultaneous presence of NO, CO, hydrocarbons and water for passive NOx adsorption",

abstract = "Pd-functionalized chabazite (Pd/SSZ-13) was evaluated for passive NOx adsorption (PNA) using low temperature combustion with diesel (LTC-D) reaction feed of the “United States Driving Research and Innovation for Vehicle efficiency and Energy sustainability” (U.S.DRIVE) protocol. Notably as per the protocol conditions, 12 % O2 + 6 % CO2 + 6 % H2O was flown in all cases. NO-uptake studies in the presence of the LTC-D feed showed a systematic decline with (NO:Pd)molar changing from 0.5 to 0.4 after 10 trials. Control experiments showed more pronounced decline for NO + CO case, with appreciable intial (NO:Pd)molar value of 0.4, yet comparable-to-the-LTC-D-feed decline after 8 trials. CO-induced particle formation and larger extent of particle sintering was also evident from TEM analysis. Other controls did not exhibit trial-dependent deactivation as (NO:Pd)molar values were similar between trials, at 0.3, 0.2, 0.5 and 0.2 for NO, NO+H2, NO + unsaturated hydrocarbon (C2H4, C3H6) and NO + saturated HC (C3H8, C10H22) feeds respectively. In addition to these quantitative differences, desorption behaviors are qualitatively different. While only one major desorption event was observed for the full LTC-D feed, NO + CO and NO + unsaturated HC-controls, desorption occured in two distinct stages for NO, NO + saturated HCs and initial-NO+H2 trials. This arises due to inherent differences in Pd sites while exposed to these chemically distinct feeds. The presence of CO and unsaturated HCs in the feed resulted in almost complete elimination of lower, sub-200 °C desorption peak. The higher temperature desorption peaks, at > 300 °C is associated with NO strongly bound to ionic Pd sites and are prevalent under reducing conditions. Using DRIFTS also, three complexes leading to PNA are assigned, [O[dbnd]N–Pd2+(OH)–Z], [O[dbnd]N–Pd2+(Z2)] and [O[dbnd]N–Pd2+(H2O)y–Z] with the latter being clearly observed upon water exposure. Pd/SSZ-13 showed higher hydrocarbon trapping than the SSZ-13 counterpart.",

keywords = "Ion-exchange, Low-temperature emission control, Palladium, Passive NOx adsorption, SSZ-13, USDRIVE",

author = "Pranaw Kunal and Toops, {Todd J.} and Kidder, {Michelle K.} and Lance, {Michael J.}",

note = "Publisher Copyright: {\textcopyright} 2021 Elsevier B.V.",

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doi = "10.1016/j.apcatb.2021.120591",

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T1 - Deactivation trends of Pd/SSZ-13 under the simultaneous presence of NO, CO, hydrocarbons and water for passive NOx adsorption

AU - Kunal, Pranaw

AU - Toops, Todd J.

AU - Kidder, Michelle K.

AU - Lance, Michael J.

PY - 2021/12/15

Y1 - 2021/12/15

N2 - Pd-functionalized chabazite (Pd/SSZ-13) was evaluated for passive NOx adsorption (PNA) using low temperature combustion with diesel (LTC-D) reaction feed of the “United States Driving Research and Innovation for Vehicle efficiency and Energy sustainability” (U.S.DRIVE) protocol. Notably as per the protocol conditions, 12 % O2 + 6 % CO2 + 6 % H2O was flown in all cases. NO-uptake studies in the presence of the LTC-D feed showed a systematic decline with (NO:Pd)molar changing from 0.5 to 0.4 after 10 trials. Control experiments showed more pronounced decline for NO + CO case, with appreciable intial (NO:Pd)molar value of 0.4, yet comparable-to-the-LTC-D-feed decline after 8 trials. CO-induced particle formation and larger extent of particle sintering was also evident from TEM analysis. Other controls did not exhibit trial-dependent deactivation as (NO:Pd)molar values were similar between trials, at 0.3, 0.2, 0.5 and 0.2 for NO, NO+H2, NO + unsaturated hydrocarbon (C2H4, C3H6) and NO + saturated HC (C3H8, C10H22) feeds respectively. In addition to these quantitative differences, desorption behaviors are qualitatively different. While only one major desorption event was observed for the full LTC-D feed, NO + CO and NO + unsaturated HC-controls, desorption occured in two distinct stages for NO, NO + saturated HCs and initial-NO+H2 trials. This arises due to inherent differences in Pd sites while exposed to these chemically distinct feeds. The presence of CO and unsaturated HCs in the feed resulted in almost complete elimination of lower, sub-200 °C desorption peak. The higher temperature desorption peaks, at > 300 °C is associated with NO strongly bound to ionic Pd sites and are prevalent under reducing conditions. Using DRIFTS also, three complexes leading to PNA are assigned, [O[dbnd]N–Pd2+(OH)–Z], [O[dbnd]N–Pd2+(Z2)] and [O[dbnd]N–Pd2+(H2O)y–Z] with the latter being clearly observed upon water exposure. Pd/SSZ-13 showed higher hydrocarbon trapping than the SSZ-13 counterpart.

AB - Pd-functionalized chabazite (Pd/SSZ-13) was evaluated for passive NOx adsorption (PNA) using low temperature combustion with diesel (LTC-D) reaction feed of the “United States Driving Research and Innovation for Vehicle efficiency and Energy sustainability” (U.S.DRIVE) protocol. Notably as per the protocol conditions, 12 % O2 + 6 % CO2 + 6 % H2O was flown in all cases. NO-uptake studies in the presence of the LTC-D feed showed a systematic decline with (NO:Pd)molar changing from 0.5 to 0.4 after 10 trials. Control experiments showed more pronounced decline for NO + CO case, with appreciable intial (NO:Pd)molar value of 0.4, yet comparable-to-the-LTC-D-feed decline after 8 trials. CO-induced particle formation and larger extent of particle sintering was also evident from TEM analysis. Other controls did not exhibit trial-dependent deactivation as (NO:Pd)molar values were similar between trials, at 0.3, 0.2, 0.5 and 0.2 for NO, NO+H2, NO + unsaturated hydrocarbon (C2H4, C3H6) and NO + saturated HC (C3H8, C10H22) feeds respectively. In addition to these quantitative differences, desorption behaviors are qualitatively different. While only one major desorption event was observed for the full LTC-D feed, NO + CO and NO + unsaturated HC-controls, desorption occured in two distinct stages for NO, NO + saturated HCs and initial-NO+H2 trials. This arises due to inherent differences in Pd sites while exposed to these chemically distinct feeds. The presence of CO and unsaturated HCs in the feed resulted in almost complete elimination of lower, sub-200 °C desorption peak. The higher temperature desorption peaks, at > 300 °C is associated with NO strongly bound to ionic Pd sites and are prevalent under reducing conditions. Using DRIFTS also, three complexes leading to PNA are assigned, [O[dbnd]N–Pd2+(OH)–Z], [O[dbnd]N–Pd2+(Z2)] and [O[dbnd]N–Pd2+(H2O)y–Z] with the latter being clearly observed upon water exposure. Pd/SSZ-13 showed higher hydrocarbon trapping than the SSZ-13 counterpart.

KW - Ion-exchange

KW - Low-temperature emission control

KW - Palladium

KW - Passive NOx adsorption

KW - SSZ-13

KW - USDRIVE

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M1 - 120591

ER -

Deactivation trends of Pd/SSZ-13 under the simultaneous presence of NO, CO, hydrocarbons and water for passive NOx adsorption

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