1. Ceria promotion on the potassium resistance of MnOx/TiO2 SCR catalysts: An experimental and DFT study.
- Author
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Peng, Yue, Li, Junhua, Si, Wenzhe, Li, Xiang, Shi, Wenbo, Luo, Jinming, Fu, Jie, Crittenden, John, and Hao, Jiming
- Subjects
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CERIUM oxides , *POTASSIUM compounds , *TITANIUM dioxide , *METAL catalysts , *DENSITY functional theory , *ACTIVATION (Chemistry) - Abstract
The deactivation of catalysts by potassium and the promotion of cerium on MnO x /TiO 2 for selective catalytic reduction (SCR) of NO with NH 3 are investigated by both experiments and DFT calculations. Catalyst poisoning by K is due to the decrease of surface acidity, the loss of reducibility and the improvement of stable nitrite/nitrate species. When the catalyst is modified by CeO 2 , SCR activities of both fresh and poisoned catalysts are improved. Cerium provides new Lewis acid sites for NH 3 adsorption, which does not seem to be influenced by K. The Ce 4f orbitals of poisoned surfaces are nearly unaffected, which preserve reducibility of catalyst for NH 3 activation. Stable, inactive nitrite species do not build up and the reactive nitrate species are still present on the surface. These advantages can be attributed to the unique active sites, the [–O–Ce–O–Mn–O–] units . These active sites induce the movement of alkali metals to assemble together, leaving more surface active sites for SCR reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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