STUDY ON ACCESSIBILITY AND CATALYTIC ACTIVITY OF Y ZEOLITE MODIFIED BY Ce-SPECIES

Abstract

Abstract: Ce-NaY zeolites with different cerium content were prepared by liquid phase ion exchange. The micro structure, textual properties and total acid content of the Y zeolites containing Ce were characterized by XRD, N2 adsorption and NH3-TPD. The influence of cerium on the acidity was studied by in-situ FTIR and the acid accessibility index (AAI) of Y zeolites before and after Ce modification were determined by different probe molecules. The micro-activities (MAT) of NaY/Ce-NaY zeolites were evaluated using Dagang light diesel as test feed. The results indicate that the original cage constructions of Y zeolites did not change after modification of cerium, while the crystal particle of Ce-NaY zeolites became smaller, and the pore structure turned to be more developed. With the introduction of more cerium, the extra-framework alumina reduced and the dealumination was suppressed, the AAI of Lewis acid gradually reduced and Bronsted acid AAI significantly increased, the MAT of REY zeolite is related with Ce content. The introduction of suitable amount of Ce species is very beneficial to improve the acid catalytic activity of the sieves.

Key words: cerium, Y zeolite, Bronsted acid, acid site, AAI, MAT

CLC Number:

References

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