Activity Improvement of Mn/Al2O3 for NH3-SCR Reaction via the Rare-Earth (Ce, La, Nd and Y) Oxides Modification

A series of rare-earth (Ce, La, Nd, and Y) oxides doped Mn/Al 2 O 3 catalysts were prepared by the impregnation method and used for the selective catalytic reduction (SCR) of NO x with NH 3 . The additions of rare-earth oxides greatly enhance the SCR catalytic activity of Mn/Al 2 O 3 , and the highe...

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Bibliographic Details
Published in:Catalysis letters 2024-07, Vol.154 (7), p.3645-3653
Main Authors: Teng, Yu, Guo, Xiaoming, Xue, Hongyan, Meng, Tao, Han, Lupeng
Format: Article
Language:English
Subjects:
Adsorption
Aluminum oxide
Ammonia
Catalysis
Catalysts
Catalytic activity
Cerium
Chemical reduction
Chemistry
Chemistry and Materials Science
Conversion
Industrial Chemistry/Chemical Engineering
Investigations
Lanthanum
Manganese dioxide
Nitrogen oxides
Organometallic Chemistry
Oxidation
Physical Chemistry
Rare earth oxides
Selective catalytic reduction
Temperature
Yttrium oxide
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Summary:A series of rare-earth (Ce, La, Nd, and Y) oxides doped Mn/Al 2 O 3 catalysts were prepared by the impregnation method and used for the selective catalytic reduction (SCR) of NO x with NH 3 . The additions of rare-earth oxides greatly enhance the SCR catalytic activity of Mn/Al 2 O 3 , and the highest activity was obtained over CeMn/Al 2 O 3 with a NO x conversion higher than 85% at 125–300 °C. The results of characterization show that the rare-earth oxides additives except for Y 2 O 3 promote the surface distribution of Mn element and enhance the ratio of chemisorbed oxygen and Mn 4+ on the surface of Mn/Al 2 O 3 . Moreover, with the introduction of rare-earth oxides, the reducibility of MnO 2 species is improved and a larger amount of the weak acid sites are obtained. The increase in the ratio of Mn 4+ and the enhancement in the reducibility of MnO 2 are the main reasons for the elevation in SCR activity of the rare-earth oxides modified Mn/Al 2 O 3 catalysts. This study sheds light on the promotional effect of rare-earth oxides over the Mn-based catalysts for SCR reaction. Graphical Abstract Rare-earth oxides greatly enhance the SCR catalytic activity of Mn/Al 2 O 3 , and the highest activity was obtained over CeMn/Al 2 O 3 with a NO x conversion higher than 85% at 125–300 °C.
ISSN:1011-372X
1572-879X
DOI:10.1007/s10562-024-04588-z