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Title: PGM based catalysts for exhaust-gas after-treatment under typical diesel, gasoline and gas engine conditions with focus on methane and formaldehyde oxidation

Abstract

In this work the HC and CO oxidation activity of Pt/Al2O3, Pd/Al2O3 and Pd-Pt/Al2O3 catalysts was compared under three exhaust-gas model conditions typical for stoichiometric gasoline as well as lean burn diesel by means of temperature programed conversion tests on laboratory test benches. In order to understand the differences in emission reduction performance, the impact of gas mixture composition was systematically studied with a particular focus on methane and formaldehyde conversion. The catalysts used in this study were prepared by incipient wetness impregnation of Al2O3 followed by washcoating on ceramic honeycombs, and were pre-treated in an equal manner before each activity test. Distinct differences in pollutant conversion were observed over the three catalysts under the investigated conditions. Pd-based monometallic and bimetallic catalysts revealed the lowest temperature for CH4 oxidation (<450 °C) under lean conditions, being lower under lean Diesel than Compressed Natural Gas (CNG) conditions. The reason for this behavior seems to be the higher water concentration in the CNG gas mixture. Furthermore, it was found that the presence of HCs shifts the conversion of methane to higher temperatures, most probably due to produced water during combustion of the HCs. Pt/Al2O3 on the other hand only converts methane at temperaturesmore » above 500 °C but no sensitivity to water or the amount of additional HCs was observed. The lowest light-out temperature for formaldehyde oxidation in excess of oxygen was measured on Pt/Al2O3 with full conversion below 125 °C. While this was the case for a model gas mixture of HCHO, H2O and O2, under simulated lean burn gas engine conditions, formaldehyde is oxidized at lower temperature on Pd-Pt/Al2O3 than on Pt/Al2O3 due to the strong inhibiting effect of CO on Pt-particles.« less

Authors:
 [1]; ORCiD logo [2];  [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]
  1. Karlsruhe Inst. of Technology (KIT) (Germany)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
Karlsruhe House of Young Scientists; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1617804
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Applied Catalysis B: Environmental
Additional Journal Information:
Journal Volume: 265; Journal Issue: C; Journal ID: ISSN 0926-3373
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Methane oxidation; Formaldehyde oxidation; Gas engine; Pd, Pt, Pd-Pt/Al2O3; Three-way catalyst (TWC); Diesel oxidation catalyst (DOC)

Citation Formats

Gremminger, Andreas, Pihl, Josh, Casapu, Maria, Grunwaldt, Jan-Dierk, Toops, Todd J., and Deutschmann, Olaf. PGM based catalysts for exhaust-gas after-treatment under typical diesel, gasoline and gas engine conditions with focus on methane and formaldehyde oxidation. United States: N. p., 2019. Web. https://doi.org/10.1016/j.apcatb.2019.118571.
Gremminger, Andreas, Pihl, Josh, Casapu, Maria, Grunwaldt, Jan-Dierk, Toops, Todd J., & Deutschmann, Olaf. PGM based catalysts for exhaust-gas after-treatment under typical diesel, gasoline and gas engine conditions with focus on methane and formaldehyde oxidation. United States. https://doi.org/10.1016/j.apcatb.2019.118571
Gremminger, Andreas, Pihl, Josh, Casapu, Maria, Grunwaldt, Jan-Dierk, Toops, Todd J., and Deutschmann, Olaf. Thu . "PGM based catalysts for exhaust-gas after-treatment under typical diesel, gasoline and gas engine conditions with focus on methane and formaldehyde oxidation". United States. https://doi.org/10.1016/j.apcatb.2019.118571. https://www.osti.gov/servlets/purl/1617804.
@article{osti_1617804,
title = {PGM based catalysts for exhaust-gas after-treatment under typical diesel, gasoline and gas engine conditions with focus on methane and formaldehyde oxidation},
author = {Gremminger, Andreas and Pihl, Josh and Casapu, Maria and Grunwaldt, Jan-Dierk and Toops, Todd J. and Deutschmann, Olaf},
abstractNote = {In this work the HC and CO oxidation activity of Pt/Al2O3, Pd/Al2O3 and Pd-Pt/Al2O3 catalysts was compared under three exhaust-gas model conditions typical for stoichiometric gasoline as well as lean burn diesel by means of temperature programed conversion tests on laboratory test benches. In order to understand the differences in emission reduction performance, the impact of gas mixture composition was systematically studied with a particular focus on methane and formaldehyde conversion. The catalysts used in this study were prepared by incipient wetness impregnation of Al2O3 followed by washcoating on ceramic honeycombs, and were pre-treated in an equal manner before each activity test. Distinct differences in pollutant conversion were observed over the three catalysts under the investigated conditions. Pd-based monometallic and bimetallic catalysts revealed the lowest temperature for CH4 oxidation (<450 °C) under lean conditions, being lower under lean Diesel than Compressed Natural Gas (CNG) conditions. The reason for this behavior seems to be the higher water concentration in the CNG gas mixture. Furthermore, it was found that the presence of HCs shifts the conversion of methane to higher temperatures, most probably due to produced water during combustion of the HCs. Pt/Al2O3 on the other hand only converts methane at temperatures above 500 °C but no sensitivity to water or the amount of additional HCs was observed. The lowest light-out temperature for formaldehyde oxidation in excess of oxygen was measured on Pt/Al2O3 with full conversion below 125 °C. While this was the case for a model gas mixture of HCHO, H2O and O2, under simulated lean burn gas engine conditions, formaldehyde is oxidized at lower temperature on Pd-Pt/Al2O3 than on Pt/Al2O3 due to the strong inhibiting effect of CO on Pt-particles.},
doi = {10.1016/j.apcatb.2019.118571},
journal = {Applied Catalysis B: Environmental},
number = C,
volume = 265,
place = {United States},
year = {2019},
month = {12}
}

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