scholarly journals Enhancing the low temperature oxidation performance over a Pt and a Pt–Pd diesel oxidation catalyst

2014 ◽  
Vol 147 ◽  
pp. 835-841 ◽  
Author(s):  
J.M. Herreros ◽  
S.S. Gill ◽  
I. Lefort ◽  
A. Tsolakis ◽  
P. Millington ◽  
...  
Keyword(s):  
Low Temperature ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Diesel Oxidation ◽  
Oxidation Performance

Characteristic Response of a Production Diesel Oxidation Catalyst Exposed to Lean and Rich PCI Exhaust

2007 ◽  
Author(s):  
Timothy J. Jacobs ◽  
Dennis N. Assanis
Keyword(s):  
Low Temperature ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Mode Switching ◽  
Lean Nox Trap ◽  
Nitric Oxides ◽  
Combustion Mode ◽  
Lean Combustion ◽  
Diesel Oxidation Catalysts ◽  
Diesel Oxidation

Although low-temperature premixed compression ignition (PCI) combustion in a light-duty diesel engine offers dramatic and simultaneous reductions in nitric oxides (NOx) and soot, associated increases in unburned hydrocarbons (HC) and carbon monoxide (CO) become unacceptable. Production diesel oxidation catalysts (DOCs) are effective in oxidizing the increased levels of HC and CO under lean combustion conditions. However, the low temperature / high CO combination under rich PCI conditions, designed as a lean NOx trap (LNT) regeneration mode, generally renders the DOC ineffective. The objectives of this study are to characterize the oxidizing efficiency of a production DOC under lean and rich PCI conditions, and attempt to identify probable causes for the observed ineffectiveness under rich PCI. The study uses several tests to characterize the behavior of the DOC under lean PCI and rich PCI combustion conditions, including: (1) steady-state feed gas characterization, (2) transient feed gas characterization, (3) air injection (4) insulated AF sweep, and (5) combustion mode switching. The DOC never becomes effective under rich PCI for any of the tests, suggesting that the platinum-based catalyst may be incorrect for use with rich PCI. Furthermore, combustion mode switching between lean PCI and rich PCI (mimicking LNT loading and regeneration) demonstrates diminishing effectiveness of the DOC during and after continuous mode transitioning.

scholarly journals Ceria-based nanoflake arrays integrated on 3D cordierite honeycombs for efficient low-temperature diesel oxidation catalyst

2019 ◽  
Vol 245 ◽  
pp. 623-634 ◽  
Author(s):  
Wenxiang Tang ◽  
Xingxu Lu ◽  
Fangyuan Liu ◽  
Shoucheng Du ◽  
Junfei Weng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Diesel Oxidation

Mass spectrometric characterization of performance of a low-temperature oxidation catalyst

1990 ◽  
Vol 60 (3) ◽  
pp. 389-398 ◽  
Author(s):  
Chen C. Hsu ◽  
Charles S. Dulcey ◽  
James S. Horwitz ◽  
Ming C. Lin
Keyword(s):  
Low Temperature ◽  
Mass Spectrometric ◽  
Oxidation Catalyst ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation

Characteristic Response of a Production Diesel Oxidation Catalyst Exposed to Lean and Rich PCI Exhaust

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Timothy J. Jacobs ◽  
Dennis N. Assanis
Keyword(s):  
Low Temperature ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Mode Switching ◽  
Lean Nox Trap ◽  
Nitric Oxides ◽  
Combustion Mode ◽  
Lean Combustion ◽  
Diesel Oxidation Catalysts ◽  
Diesel Oxidation

Although low-temperature premixed compression ignition (PCI) combustion in a light-duty diesel engine offers dramatic and simultaneous reductions in nitric oxides (NOx) and soot, associated increases in unburned hydrocarbons (HC) and carbon monoxide (CO) become unacceptable. Production diesel oxidation catalysts (DOCs) are effective in oxidizing the increased levels of HC and CO under lean combustion conditions. However, the low-temperature∕high CO combination under rich PCI conditions, designed as a lean NOx trap (LNT) regeneration mode, generally renders the DOC ineffective. The objectives of this study are to characterize the oxidizing efficiency of a production DOC under lean and rich PCI conditions, and attempt to identify probable causes for the observed ineffectiveness under rich PCI. The study uses several tests to characterize the behavior of the DOC under lean PCI and rich PCI combustion conditions, including (1) steady-state feed gas characterization, (2) transient feed gas characterization, (3) air injection (4) insulated air-fuel sweep, and (5) combustion mode switching. The DOC never becomes effective under rich PCI for any of the tests, suggesting that the platinum-based catalyst may be incorrect for use with rich PCI. Furthermore, combustion mode switching between lean PCI and rich PCI (mimicking LNT loading and regeneration) demonstrates diminishing effectiveness of the DOC during and after continuous mode transitioning.

scholarly journals Example on the Use of Operando Spectroscopy for Developing Mechanistic Insights into Industrial Catalysts and Catalytic Processes

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 200
Author(s):  
Claire Chunjuan Zhang ◽  
Shiang Sung ◽  
Sage Hartlaub ◽  
Ivan Petrovic ◽  
Bilge Yilmaz
Keyword(s):  
Spectroscopic Analysis ◽  
Process Development ◽  
Catalyst Surface ◽  
Catalyst Support ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Alumina Support ◽  
Co Conversion ◽  
Diesel Oxidation ◽  
Oxidation Performance

In this contribution, we present an industrial example on how tailored operando spectroscopic methodologies provide the insights needed for the development of new catalytic technologies and support their global utilization. We describe the use of operando spectroscopic methods to investigate how the CO oxidation performance of catalysts is impacted by NOx, H2, temperature, and moisture, as well as the catalyst support. This operando spectroscopic analysis provides mechanistic insights into the current diesel oxidation catalyst (DOC) system and shines light on the material and process development efforts on future DOC catalysts for low-temperature emission control to meet the new regulations. This investigation has shown that at cold-start temperatures, the nitrate growth can occupy the precious metal–alumina support interfacial sites that are critical for O2 dissociation and/or oxygen transfer and hinder CO conversion. Introduction of hydrogen on the catalyst surface can inhibit the nitrate growth, which in turn keeps these critical interfacial sites open.

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