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Title: Evaluation of Mn and Sn-Modified Pd-Ce-Based Catalysts for Low-Temperature Diesel Exhaust Oxidation

Pd-impregnated Ce-based catalysts were tested for carbon monoxide (CO) and hydrocarbon (HC) oxidation under challenging low-temperature diesel combustion conditions. The results indicate that the light-off temperatures for CO over Pd/CeO 2, Pd/MnO x-CeO 2 (Pd/MC), and Pd/SnO 2-MnO x-CeO 2 (Pd/SMC) catalysts shift to higher temperatures in the presence of simulated diesel exhaust gas. The lowest T 50 for CO is observed over Pd/MC at 173 °C, whereas Pd/CeO 2 is shown to oxidize most of the HCs at temperatures below 400 °C. In all catalysts, the oxidation of HCs starts right after the onset of CO oxidation, revealing that the competitive adsorption of CO, NO, and alkenes controls the catalytic activity. Further evaluation of the catalytic activity in the presence of only CO and C 3H 6 reveals the immediate inhibiting effect of C 3H 6 at catalyst temperatures below 150 °C. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments performed over Pd/CeO 2, Pd/MC, and Pd/SMC show that C 3H 6 inhibits the formation of carbonyl species on Pd n+ sites, which limits the catalytic activity for CO. Lastly, such inhibition is observed on all supports, implying that the activity is independent of oxygen storage capacitymore » (OSC) or lattice oxygen reducibility of the supports in the presence of C 3H 6.« less
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  1. Univ. of South Carolina, Columbia, SC (United States). SmartState Center for Strategic Approaches to the Generation of Electricity (SAGE), Dept. of Chemical Engineering
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines, and Emissions Research Center
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Emission Control Science & Technology
Additional Journal Information:
Journal Volume: 3; Journal Issue: 1; Journal ID: ISSN 2199-3629
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center (FEERC); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Low-temperature diesel oxidation; Pd; Solid solution; Hydrocarbon inhibition
OSTI Identifier: