Abstract
A series of manganese-cerium oxide catalysts were prepared by co-precipitation method and used for low temperature selective catalytic reduction (SCR) of NO{sub x} with ammonia in the presence of excess O{sub 2}. These catalysts were characterized by X-ray diffraction (XRD), surface area measurement and FTIR. The experimental results showed that the best Mn-Ce mixed-oxide catalyst yielded 95% NO conversion at 150C at a space velocity of 42,000h{sup -1}. As the manganese content was increased from 0 to 40% (i.e. the molar ratio of Mn/(Mn+Ce)), NO conversion increased significantly, but decreased at higher manganese contents. The most active catalyst was obtained with a molar Mn/(Mn+Ce) ratio of 0.4. Only N{sub 2} rather than N{sub 2}O was found in the product when the temperature was below 150C. At higher temperatures, trace amounts of N{sub 2}O were detected. A mechanistic pathway for this reaction was proposed based on earlier findings and FTIR results obtained in this work. The initial step was the adsorption of NH{sub 3} on Lewis acid sites of catalyst, followed by reaction with nitrite species to produce N{sub 2} and H{sub 2}O. Possible intermediates are proposed and all the intermediates could transform into NH{sub 2}NO, which could further react to
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Qi, Gongshin;
Yang, Ralph T;
[1]
Chang, Ramsay
[2]
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109-2136 (United States)
- Air Pollution Control, Power Generation, Electric Power Research Institute, Palo Alto, CA 94304-1395 (United States)
Citation Formats
Qi, Gongshin, Yang, Ralph T, and Chang, Ramsay.
MnO{sub x}-CeO{sub 2} mixed oxides prepared by co-precipitation for selective catalytic reduction of NO with NH{sub 3} at low temperatures.
Netherlands: N. p.,
2004.
Web.
doi:10.1016/j.apcatb.2004.01.023.
Qi, Gongshin, Yang, Ralph T, & Chang, Ramsay.
MnO{sub x}-CeO{sub 2} mixed oxides prepared by co-precipitation for selective catalytic reduction of NO with NH{sub 3} at low temperatures.
Netherlands.
https://doi.org/10.1016/j.apcatb.2004.01.023
Qi, Gongshin, Yang, Ralph T, and Chang, Ramsay.
2004.
"MnO{sub x}-CeO{sub 2} mixed oxides prepared by co-precipitation for selective catalytic reduction of NO with NH{sub 3} at low temperatures."
Netherlands.
https://doi.org/10.1016/j.apcatb.2004.01.023.
@misc{etde_20502446,
title = {MnO{sub x}-CeO{sub 2} mixed oxides prepared by co-precipitation for selective catalytic reduction of NO with NH{sub 3} at low temperatures}
author = {Qi, Gongshin, Yang, Ralph T, and Chang, Ramsay}
abstractNote = {A series of manganese-cerium oxide catalysts were prepared by co-precipitation method and used for low temperature selective catalytic reduction (SCR) of NO{sub x} with ammonia in the presence of excess O{sub 2}. These catalysts were characterized by X-ray diffraction (XRD), surface area measurement and FTIR. The experimental results showed that the best Mn-Ce mixed-oxide catalyst yielded 95% NO conversion at 150C at a space velocity of 42,000h{sup -1}. As the manganese content was increased from 0 to 40% (i.e. the molar ratio of Mn/(Mn+Ce)), NO conversion increased significantly, but decreased at higher manganese contents. The most active catalyst was obtained with a molar Mn/(Mn+Ce) ratio of 0.4. Only N{sub 2} rather than N{sub 2}O was found in the product when the temperature was below 150C. At higher temperatures, trace amounts of N{sub 2}O were detected. A mechanistic pathway for this reaction was proposed based on earlier findings and FTIR results obtained in this work. The initial step was the adsorption of NH{sub 3} on Lewis acid sites of catalyst, followed by reaction with nitrite species to produce N{sub 2} and H{sub 2}O. Possible intermediates are proposed and all the intermediates could transform into NH{sub 2}NO, which could further react to produce N{sub 2} and H{sub 2}O.}
doi = {10.1016/j.apcatb.2004.01.023}
journal = []
issue = {2}
volume = {51}
journal type = {AC}
place = {Netherlands}
year = {2004}
month = {Jul}
}
title = {MnO{sub x}-CeO{sub 2} mixed oxides prepared by co-precipitation for selective catalytic reduction of NO with NH{sub 3} at low temperatures}
author = {Qi, Gongshin, Yang, Ralph T, and Chang, Ramsay}
abstractNote = {A series of manganese-cerium oxide catalysts were prepared by co-precipitation method and used for low temperature selective catalytic reduction (SCR) of NO{sub x} with ammonia in the presence of excess O{sub 2}. These catalysts were characterized by X-ray diffraction (XRD), surface area measurement and FTIR. The experimental results showed that the best Mn-Ce mixed-oxide catalyst yielded 95% NO conversion at 150C at a space velocity of 42,000h{sup -1}. As the manganese content was increased from 0 to 40% (i.e. the molar ratio of Mn/(Mn+Ce)), NO conversion increased significantly, but decreased at higher manganese contents. The most active catalyst was obtained with a molar Mn/(Mn+Ce) ratio of 0.4. Only N{sub 2} rather than N{sub 2}O was found in the product when the temperature was below 150C. At higher temperatures, trace amounts of N{sub 2}O were detected. A mechanistic pathway for this reaction was proposed based on earlier findings and FTIR results obtained in this work. The initial step was the adsorption of NH{sub 3} on Lewis acid sites of catalyst, followed by reaction with nitrite species to produce N{sub 2} and H{sub 2}O. Possible intermediates are proposed and all the intermediates could transform into NH{sub 2}NO, which could further react to produce N{sub 2} and H{sub 2}O.}
doi = {10.1016/j.apcatb.2004.01.023}
journal = []
issue = {2}
volume = {51}
journal type = {AC}
place = {Netherlands}
year = {2004}
month = {Jul}
}