Improved high temperature stability of NH₃-SCR catalysts based on rare earth vanadates supported on TiO₂WO₃SiO₂

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• 作者：Marzia Casanova^a ; Karl Schermanz^b ; Jordi Llorca^c ; Alessandro Trovarelli^a ; ^{trovarelli@uniud.it}
• 关键词：NH3-SCR ; Selective catalytic reduction ; Rare earth vanadates ; deNOx ; Vanadia/titania catalysts
• 刊名：Catalysis Today
• 出版年：2012
• 期刊代码：13_09205861
• 类别：ce
• 出版时间：30 April, 2012
• 卷：184
• 期：1
• 页码：227-236
• 文件大小：1387 K

摘要

The ammonia SCR activity of a series of rare earth vanadates supported over TiO₂WO₃SiO₂ was investigated after thermal treatment in the temperature range 700-750 掳C and their properties studied by XRD, TPR, BET and HRTEM analysis. It was found that the thermal stability of the catalyst is remarkably higher than that observed in traditional vanadia-based materials, with the rare earth vanadate being able to suppress the unfavorable transformation of anatase to rutile and the consequent surface area drop. The deNO_x activity after aging was higher than that observed over V₂O₅/TiO₂WO₃SiO₂ and dependent on the nature of the rare earth element. A group of elements comprising Tb, Er, Dy, Sm and Gd showed excellent resistance to deactivation and high activity after aging while a second group with Ce, La, Nd and Pr was more sensitive to thermal treatment and less active. This was correlated to their position in the periodic table and to their ability to alter the characteristics of the VO bond and the acid/base surface properties.