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This content will become publicly available on September 21, 2017

Title: Kinetic and mechanistic study of bimetallic Pt-Pd/Al2O3 catalysts for CO and C3H6 oxidation

Low temperature combustion (LTC) diesel engines are being developed to meet increased fuel economy demands. However, some LTC engines emit higher levels of CO and hydrocarbons and therefore diesel oxidation catalyst (DOC) efficiency will be critical. Here, CO and propylene oxidation were studied, as representative LTC exhaust components, over model bimetallic Pt-Pd/γ-Al2O3 catalysts. During CO oxidation tests, monometallic Pt suffered the most extensive inhibition which was correlated to a greater extent of dicarbonyl species formation. Pd and Pd-rich bimetallics were inhibited by carbonate formation at higher temperatures. The 1:1 and 3:1 Pt:Pd bimetallic catalysts did not form the dicarbonyl species to the same extent as the monometallic Pt sample, and therefore did not suffer from the same level of inhibition. Similarly they also did not form carbonates to as large an extent as the Pd-rich samples and were therefore not as inhibited from this intermediate surface species at higher temperature. The Pd-rich samples were relatively poor propylene oxidation catalysts; and partial oxidation product accumulation deactivated these catalysts. Byproducts observed include acetone, ethylene, acetaldehyde, acetic acid, formaldehyde and CO. For CO and propylene co-oxidation, the onset of propylene oxidation was not observed until complete CO oxidation was achieved, and the bimetallicsmore » showed higher activity. In conclusion, this was again related to less extensive poisoning, less dicarbonyl species formation and less overall partial oxidation product accumulation.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Univ. of Houston, Houston, TX (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1330523
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Applied Catalysis. B, Environmental
Additional Journal Information:
Journal Volume: 202; Journal Issue: C; Journal ID: ISSN 0926-3373
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center
Sponsoring Org:
ORNL work for others; USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY oxidation catalyst; CO oxidation; propylene oxidation; bimetallic Pt:Pd catalysts