Reduction of Low Temperature Engine Pollutants by Understanding the Exhaust Species Interactions in a Diesel Oxidation Catalyst

The interactions between exhaust gas species and their effect (promotion or inhibition) on the light-off and activity of a diesel oxidation catalyst (DOC) for the removal of pollutants are studied, using actual engine exhaust gases from the combustion of diesel, alternative fuels (rapeseed methyl es...

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Bibliographic Details
Published in:Environmental science & technology 2014-02, Vol.48 (4), p.2361-2367
Main Authors: Lefort, I, Herreros, J. M, Tsolakis, A
Format: Article
Language:English
Subjects:
Adsorption
Air Pollutants - analysis
Applied sciences
Atmospheric pollution
Carbon Monoxide - analysis
Catalysis
Cold Temperature
Diesel engines
Emissions
Exact sciences and technology
Gasoline - analysis
Hydrocarbons
Hydrocarbons - analysis
Motor Vehicles
Nitric Oxide - analysis
Nitrogen Dioxide - analysis
Oxidation
Oxidation-Reduction
Pollutants
Pollution
Prevention and purification methods
Temperature
Transports and other
Vehicle Emissions - analysis
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Summary:The interactions between exhaust gas species and their effect (promotion or inhibition) on the light-off and activity of a diesel oxidation catalyst (DOC) for the removal of pollutants are studied, using actual engine exhaust gases from the combustion of diesel, alternative fuels (rapeseed methyl ester and gas-to-liquid fuel) and diesel/propane dual fuel combustion. The activity of the catalyst was recorded during a heating temperature ramp where carbon monoxide (CO) and hydrocarbon (HC) light-off curves were obtained. From the catalyst activity tests, it was found that the presence of species including CO, medium-heavy HC, alkenes, alkanes, and NO x and their concentration influence the catalyst ability to reduce CO and total HC emissions before release to the atmosphere. CO could inhibit itself and other species oxidation (e.g., light and medium-heavy hydrocarbons) while suffering from competitive adsorption with NO. Hydrocarbon species were also found to inhibit their own oxidation as well as CO through adsorption competition. On the other hand, NO2 was found to promote low temperature HC oxidation through its partial reduction, forming NO. The understanding of these exhaust species interactions within the DOC could aid the design of an efficient aftertreatment system for the removal of diesel exhaust pollutants.
ISSN:0013-936X
1520-5851
DOI:10.1021/es4051499