Effect of surface Lewis acidity on selective catalytic reduction of NO by C3H6 over calcined hydrotalcite

Authors: Deling Yuan, Xinyong Li, Qidong Zhao, Jijun Zhao, Shaomin Liu, Moses Tadé

Abstract:
The selective catalytic reduction (SCR) of NO by C₃H₆ has been studied over a series of calcined hydrotalcite, which were prepared by four different methods to obtain various Lewis acid sites. The catalysts have been investigated by X-ray powder diffractometer, N₂ adsorption, Temperature-programmed desorption of NH₃ (NH₃-TPD), pyridine adsorption FTIR (Py-FTIR), Temperature-programmed desorption of NO + O₂ (NO + O₂-TPD) and in situ FTIR techniques. The Lewis acid sites could be changed with the transformation of the crystalline structure from the mixed oxides of MgO and Al₂O₃ to spinel phase. It is demonstrated that Lewis acid sites play an important role in determining the catalytic performance of SCR by C₃H₆ over calcined hydrotalcite catalysts. Various nitrate species as the key intermediate species for SCR could form at Lewis acid sites during the process of the reaction under lean-burn condition.

Keywords:
Lewis acidity
Hydrotalcite
Temperature-programmed desorption
In situ FTIR

Published in: Applied catalysis A: General  (Volume 451, Pages 1-288, 31 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Effect of surface Lewis acidity on selective catalytic reduction of NO by C3H6 over calcined hydrotalcite

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