Soot oxidation over K-doped manganese and iron spinels — How potassium precursor nature and doping level change the catalyst activity

2014 ◽  
Vol 43 ◽  
pp. 34-37 ◽  
Author(s):  
Piotr Legutko ◽  
Tomasz Jakubek ◽  
Wojciech Kaspera ◽  
Paweł Stelmachowski ◽  
Zbigniew Sojka ◽  
...  
Keyword(s):  
Doping Level ◽  
Catalyst Activity ◽  
Soot Oxidation ◽  
Level Change

scholarly journals Influence of the Preparation Method of Ag-K/CeO2-ZrO2-Al2O3 Catalysts on Their Structure and Activity for the Simultaneous Removal of Soot and NOx

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 294 ◽  
Author(s):  
Anna Cooper ◽  
Thomas E. Davies ◽  
David J. Morgan ◽  
Stan Golunski ◽  
Stuart H. Taylor
Keyword(s):  
Preparation Method ◽  
Catalyst Activity ◽  
Chemical Vapor ◽  
Soot Oxidation ◽  
Simultaneous Removal ◽  
Oxidation Activity ◽  
Wet Impregnation ◽  
Incipient Wetness ◽  
The Difference ◽  
Soot Oxidation Activity

Ag/CeO2-ZrO2-Al2O3, a known catalyst for the simultaneous removal of NOx and soot, was modified by the addition of K, and was prepared using various techniques: wet impregnation, incipient wetness, and chemical vapor impregnation at different temperatures. The effect of the preparation method on catalyst activity was studied. It was found that catalysts prepared via wet impregnation, incipient wetness, and chemical vapor impregnation at 80 °C were able to utilize in situ formed N2O at low temperatures, to simultaneously remove NOx and soot. The difference in preparation method affected the catalyst’s ability to produce and use N2O as an oxidant for soot. The temperature at which chemical vapor impregnation was performed greatly influenced the catalyst’s ability to oxidize soot. The introduction of K to the Ag/CeO2-ZrO2-Al2O3 vastly improved the soot oxidation activity, particularly for the catalyst prepared via wet impregnation. However, the incorporation of K had an adverse effect on the reduction of NOx.

scholarly journals Reactive Fe-O-Ce Sites in Ceria Catalysts for Soot Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 815 ◽  
Author(s):  
Boyu Li ◽  
Abhishek Raj ◽  
Eric Croiset ◽  
John Z. Wen
Keyword(s):  
Oxygen Vacancy ◽  
Photoelectron Spectroscopy ◽  
Catalyst Activity ◽  
Solution Combustion Synthesis ◽  
Soot Oxidation ◽  
Solution Combustion ◽  
Preparation Methods ◽  
Fe Content ◽  
Ceria Catalysts ◽  
Co Precipitation

This study investigates the role of oxygen vacancy on Fe-doped CeO2 catalyst activity for soot oxidation. The oxygen vacancy was assessed through Ce3+ content. The Fe content was varied between 0 and 30% for two catalyst preparation methods, co-precipitation (CP) and solution combustion synthesis (SCS). X-ray photoelectron spectroscopy indicates that ceria exists as both Ce4+ and Ce3+, while iron is present only as Fe3+. The catalyst’s activity was evaluated by ignition (T10) and combustion (T50) temperatures using thermogravimetric analysis. Optimum Fe contents yielding the highest activity were found to be 10% and 5% for CP and SCS catalysts, respectively. The surface area and morphology showed a moderate effect on catalyst activity, because catalytic soot oxidation involves solid–solid contact. More importantly, regardless of the fabrication method, it was found that Ce3+ content, which is closely related to oxygen vacancies, plays the most important role in affecting the catalyst activity.

Doping level change of polyaniline film during its electrochemical growth process

2004 ◽  
Vol 92 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Chen Liu ◽  
Jiaxin Zhang ◽  
Gaoquan Shi ◽  
Feng'en Chen
Keyword(s):  
Doping Level ◽  
Growth Process ◽  
Polyaniline Film ◽  
Electrochemical Growth ◽  
Level Change

Soot oxidation over CeO2 and Ag/CeO2: Factors determining the catalyst activity and stability during reaction

2016 ◽  
Vol 337 ◽  
pp. 188-198 ◽  
Author(s):  
Shuang Liu ◽  
Xiaodong Wu ◽  
Wei Liu ◽  
Wenming Chen ◽  
Rui Ran ◽  
...  
Keyword(s):  
Catalyst Activity ◽  
Soot Oxidation

Doping level change of polythiophene film during its electrochemical growth process

2002 ◽  
Vol 4 (12) ◽  
pp. 2685-2690 ◽  
Author(s):  
Mingxiao Fu ◽  
Gaoquan Shi ◽  
Fengen Chen ◽  
Xiaoyin Hong
Keyword(s):  
Doping Level ◽  
Growth Process ◽  
Electrochemical Growth ◽  
Level Change ◽  
Polythiophene Film

Mean-level change in pathological personality dimensions over 4 decades in clinical and community samples: A cross-sectional study.

2020 ◽  
Vol 11 (6) ◽  
pp. 409-417
Author(s):  
José Ruiz ◽  
Fernando Gutiérrez ◽  
Josep Maria Peri ◽  
Anton Aluja ◽  
Eva Baillés ◽  
...  
Keyword(s):  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Personality Dimensions ◽  
Level Change

Conductivity of n-doped polyacetylene : dependence on doping level and temperature

1992 ◽  
Vol 89 ◽  
pp. 977-986 ◽  
Author(s):  
N Foxonet ◽  
P Bernier ◽  
J Voit
Keyword(s):  
Doping Level

Phanerozoic Oxygen

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Oxygen Consumption ◽  
Organic Carbon ◽  
Sea Level ◽  
Time Scale ◽  
Atmospheric Oxygen ◽  
Sea Level Change ◽  
Oxygen Production ◽  
Level Change ◽  
History Of ◽  
Geologic Processes

This chapter discusses the modeling of the history of atmospheric oxygen. The most recently deposited sediments will also be the most prone to weathering through processes like sea-level change or uplift of the land. Thus, through rapid recycling, high rates of oxygen production through the burial of organic-rich sediments will quickly lead to high rates of oxygen consumption through the exposure of these organic-rich sediments to weathering. From a modeling perspective, rapid recycling helps to dampen oxygen changes. This is important because the fluxes of oxygen through the atmosphere during organic carbon and pyrite burial, and by weathering, are huge compared to the relatively small amounts of oxygen in the atmosphere. Thus, all of the oxygen in the present atmosphere is cycled through geologic processes of oxygen liberation (organic carbon and pyrite burial) and consumption (weathering) on a time scale of about 2 to 3 million years.

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