We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Reaction Kinetics of CH Oxidation for Various Reaction Pathways Over Diesel Oxidation Catalysts.
- Authors
Oh, Harry; Pieta, Izabela; Luo, Jinyong; Epling, William
- Abstract
Reaction kinetics studies of CH oxidation over Pt/AlO and Pt/SiO catalysts were characterized using temperature-programmed oxidation with different oxidants: O, NO and surface nitrates. Activation energies and conversion performance were compared in order to determine which hydrocarbon oxidation reaction pathway(s) is relevant in diesel exhaust gas aftertreatment applications. NO adsorption did not occur on the SiO surface so the reaction between CH and NO could be isolated, i.e. no nitrate effect would complicate the analysis and their significance could be decoupled. These results were then compared with Pt/AlO where surface nitrates did form upon exposure to NO. The onset of CH oxidation was observed at a lower temperature with O than with NO, but the activation energy was lower with NO. This apparent discrepancy is related to the different oxidant concentrations used and the different adsorption pathways. The results indicate that hydrocarbons must be activated first for oxidation to begin, for either NO or O. In analyzing the reaction between CH and nitrates, the reaction did not occur until NO started to desorb from the catalyst at higher temperatures, i.e. when nitrates became unstable and decomposed, thus providing a readily available oxidant source. However, when O was added to the nitrate/CH system, the reaction began at even lower temperature than with just CH and O. Nitrate consumption was also observed once oxidation began. The presence of the combination of nitrates and O resulted in a lower CH oxidation activation energy.
- Subjects
CHEMICAL kinetics; CARBON-hydrogen bonds; OXIDATION; DIESEL fuels; CATALYSTS; TEMPERATURE effect; ACTIVATION energy
- Publication
Topics in Catalysis, 2013, Vol 56, Issue 18-20, p1916
- ISSN
1022-5528
- Publication type
Article
- DOI
10.1007/s11244-013-0128-9