Catalytic soot oxidation over Ce- and Cu-doped hydrotalcites-derived mesoporous mixed oxides
Catalytic soot oxidation over Ce- and Cu-doped hydrotalcites-derived mesoporous mixed oxides
Ce- and Cu-doped hydrotalcites derived mixed oxides were prepared through co-precipitation and calcination method, and their catalytic activities for soot oxidation with O2 and O2/NO were investigated. The solids were characterized by XRD, TG-DTG, BET, H2-TPR, in situ FTIR and TPO techniques. All the catalysts precursors showed the typical diffraction patterns of hydrotalcite-like materials having layered structure. The derived mixed oxides exhibited mesoporous properties with specific surface area of 45–160 m2/g. After both Ce and Cu incorporated, mixed crystalline phases of CuO (tenorite), CeO2 (fluorite) and MgAl2O4 (spinel) were formed. As a result, the NOx adsorption capacity of this catalyst was largely increased to 201 µmol/g, meanwhile, it was also the most effective to convert NO into NO2 in the sorption process due to the enhanced reducibility. The in situ FTIR spectra revealed that NOx were stored mainly as chelating bidentate and monodentate nitrate. The interaction effect between Cu and Ce in the mixed oxide resulted in different NOx adsorption behavior. Compared with the non-catalyzed soot oxidation, soot conversion curves over the mixed oxides catalysts shift to low temperature in O2. The presence of NO in the gas phase significantly enhanced the soot oxidation activity with ignition temperature decreased to about 320°C, which is due to NO conversion to NO2 over the catalyst followed by the reaction of NO2 with soot. This explains the cooperative effect of Ce and Cu in the mixed oxide on soot oxidation with high activity and 100% selectivity to CO2 formation.
7087-7096
Wang, Zhongpeng
a0fb2552-42ae-4fa6-8496-5cdf5892638f
Wang, Liguo
7a1e08ea-2738-4eda-be28-a0a6b5e03300
He, Fang
51b85745-55e8-4b28-a42d-15e9d17059fd
Jiang, Zheng
bcf19e78-f5c3-48e6-802b-fe77bd12deab
Xiao, Tiancun
90161b4f-4483-4b4f-8db6-6614b001ac54
Zhang, Zhaoliang
c7bff934-7ca1-445f-829e-765ee1027a91
September 2014
Wang, Zhongpeng
a0fb2552-42ae-4fa6-8496-5cdf5892638f
Wang, Liguo
7a1e08ea-2738-4eda-be28-a0a6b5e03300
He, Fang
51b85745-55e8-4b28-a42d-15e9d17059fd
Jiang, Zheng
bcf19e78-f5c3-48e6-802b-fe77bd12deab
Xiao, Tiancun
90161b4f-4483-4b4f-8db6-6614b001ac54
Zhang, Zhaoliang
c7bff934-7ca1-445f-829e-765ee1027a91
Wang, Zhongpeng, Wang, Liguo, He, Fang, Jiang, Zheng, Xiao, Tiancun and Zhang, Zhaoliang
(2014)
Catalytic soot oxidation over Ce- and Cu-doped hydrotalcites-derived mesoporous mixed oxides.
Journal of Nanoscience and Nanotechnology, 14 (9), .
(doi:10.1166/jnn.2014.8944).
Abstract
Ce- and Cu-doped hydrotalcites derived mixed oxides were prepared through co-precipitation and calcination method, and their catalytic activities for soot oxidation with O2 and O2/NO were investigated. The solids were characterized by XRD, TG-DTG, BET, H2-TPR, in situ FTIR and TPO techniques. All the catalysts precursors showed the typical diffraction patterns of hydrotalcite-like materials having layered structure. The derived mixed oxides exhibited mesoporous properties with specific surface area of 45–160 m2/g. After both Ce and Cu incorporated, mixed crystalline phases of CuO (tenorite), CeO2 (fluorite) and MgAl2O4 (spinel) were formed. As a result, the NOx adsorption capacity of this catalyst was largely increased to 201 µmol/g, meanwhile, it was also the most effective to convert NO into NO2 in the sorption process due to the enhanced reducibility. The in situ FTIR spectra revealed that NOx were stored mainly as chelating bidentate and monodentate nitrate. The interaction effect between Cu and Ce in the mixed oxide resulted in different NOx adsorption behavior. Compared with the non-catalyzed soot oxidation, soot conversion curves over the mixed oxides catalysts shift to low temperature in O2. The presence of NO in the gas phase significantly enhanced the soot oxidation activity with ignition temperature decreased to about 320°C, which is due to NO conversion to NO2 over the catalyst followed by the reaction of NO2 with soot. This explains the cooperative effect of Ce and Cu in the mixed oxide on soot oxidation with high activity and 100% selectivity to CO2 formation.
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Published date: September 2014
Organisations:
Faculty of Engineering and the Environment
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Local EPrints ID: 363721
URI: http://eprints.soton.ac.uk/id/eprint/363721
ISSN: 1533-4880
PURE UUID: 5a5a2b2d-72fa-41fc-9de2-6dff7f04bc2b
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Date deposited: 01 Apr 2014 14:17
Last modified: 15 Mar 2024 03:47
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Author:
Zhongpeng Wang
Author:
Liguo Wang
Author:
Fang He
Author:
Tiancun Xiao
Author:
Zhaoliang Zhang
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