Effect of cerium ions initial distribution on the crystalline structure and catalytic performance of CeY zeolite

Ce Y samples with different cerium（Ce） ions initial distribution were prepared by diverse preparation processes. The correlative influence of Ce ions distribution on the intracrystalline structure and catalytic mechanism of Y-type zeolite was studied by X-ray diffraction（XRD）, Rietveld refinement, X...

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Published inJournal of rare earths Vol. 35; no. 8; pp. 791 - 799
Main Author 张乐 秦玉才 汲德强 储刚 高雄厚 张晓彤 宋丽娟
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.08.2017
Subjects
catalytic cracking
crystalline structure
ions distribution
NH3-TPD
rare earths
Rietveld
Rietveld refinement
X射线能谱仪
Y-type zeolite
催化性能
初始分布
晶体结构
程序升温脱附
铈离子
Y-type zeolite
Rietveld refinement
catalytic cracking
ions distribution
crystalline structure
rare earths
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Summary:Ce Y samples with different cerium（Ce） ions initial distribution were prepared by diverse preparation processes. The correlative influence of Ce ions distribution on the intracrystalline structure and catalytic mechanism of Y-type zeolite was studied by X-ray diffraction（XRD）, Rietveld refinement, X-ray fluorescence spectrometry（XRF）, energy-dispersive X-ray spectroscopy（EDS）, infrared（IR） spectra, NH3 temperature-programmed desorption（NH3-TPD）, N2 physical adsorption-desorption and micro-activity test（MAT）. The results indicated that Ce ions were concentrated on the surface（supercage） of Ce Y zeolite would reduce the number of acid sites and the ratio of Br？nsted acid and Lewis acid（B/L）. Once Ce ions concentrated in the sodalite cage, it would participate in the coordination with framework oxygen atoms under the condition of steric hindrance. Meanwhile, Ce ions would preferentially promote the B/L value of weak acid by retaining more intracrystalline framework Al atoms in sodalite cage, which was beneficial to the conversion of heavy oil in FCC process. The optimal initial-distribution of Ce ions could not only save the consumption of rare earth resources but also give the best catalytic performance of Ce Y zeolite catalysts, and these advantages and attributes enabled it to have the potential to be applied in industrial applications.
Bibliography:11-2788/TF
Y-type zeolite;rare earths;Rietveld refinement;ions distribution;crystalline structure;catalytic cracking
Ce Y samples with different cerium（Ce） ions initial distribution were prepared by diverse preparation processes. The correlative influence of Ce ions distribution on the intracrystalline structure and catalytic mechanism of Y-type zeolite was studied by X-ray diffraction（XRD）, Rietveld refinement, X-ray fluorescence spectrometry（XRF）, energy-dispersive X-ray spectroscopy（EDS）, infrared（IR） spectra, NH3 temperature-programmed desorption（NH3-TPD）, N2 physical adsorption-desorption and micro-activity test（MAT）. The results indicated that Ce ions were concentrated on the surface（supercage） of Ce Y zeolite would reduce the number of acid sites and the ratio of Br？nsted acid and Lewis acid（B/L）. Once Ce ions concentrated in the sodalite cage, it would participate in the coordination with framework oxygen atoms under the condition of steric hindrance. Meanwhile, Ce ions would preferentially promote the B/L value of weak acid by retaining more intracrystalline framework Al atoms in sodalite cage, which was beneficial to the conversion of heavy oil in FCC process. The optimal initial-distribution of Ce ions could not only save the consumption of rare earth resources but also give the best catalytic performance of Ce Y zeolite catalysts, and these advantages and attributes enabled it to have the potential to be applied in industrial applications.
ISSN:1002-0721
2509-4963
DOI:10.1016/S1002-0721(17)60978-5