Effect of cation location on the hydrothermal stability of rare earth-exchanged Y zeolites

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• 作者：Xiaohui Du^a ; ^b ; Xionghou Gao^a ; ^b ; ^{gaoxionghou@petrochina.com.cn} ; Haitao Zhang^b ; Xueli Li^b ; Pusheng Liu^b
• 关键词：Rare earth ; Zeolite ; Rietveld refinement ; Hydrothermal stability
• 刊名：Catalysis Communications
• 出版年：2013
• 出版时间：5 May, 2013
• 年：2013
• 卷：35
• 期：Complete
• 页码：17-22
• 全文大小：556 K

文摘

NaY zeolites ion-exchanged with rare earth (RE) cations (La^3 +, Ce^3 +, Pr^3 +, Nd^3 +) were prepared by a double-exchange double-calcination method. The position, occupation and coordination of the zeolite extra-framework RE cations were identified by powder X-ray diffraction with the Rietveld refinement. The results indicate that Ce species were insusceptible to migration into the sodalite cages compared with others under the same circumstances, which may be attributed to the facile formation of CeO₂(IV) based on Ce(OH)^2 + and oxygen as well as the retarded migration of tetravalent cerium. Furthermore, the stability and activity of REY zeolites increased with decreasing ionic radii of RE elements.