Preparation of Ni@ZSM-5 Catalysts by In-Situ Encapsulation and Its Performance in the Alkylation of Benzene With Methanol

In this study, Ni was encapsulated into ZSM-5 nanocrystals by in-situ encapsulation method, and a series of Ni @ ZSM-5 catalysts with 0.2%, 1.0% and 4.0% mass fractions of encapsulated NiO -were successfully prepared by adjusting the metal content. The catalysts -were characterized by X-ray diffraction (XRD), scanning electron microscopy ( SEM ) , transmission electron microscopy (TEM) , N2-physical adsorption-desorption (BET) and ammonia programmed temperature desorption (NH3-TPD) , and the effect of Ni encapsulation amount on the alkylation of benzene -with methanol -was investigated in detail. The results show that the Ni content has little effects on the particle size and morphology of the catalysts, the total pore volume is decreased slightly, and little change occurs in the specific surface area, micropore volume and acid amount; the Ni content has a significant effect on the stability of the catalysts. At the reaction temperature of 460 °C , pressure of 0. 1 MPa, and 1.0% mass fraction of encapsulated NiO, the conversion rate of benzene can reach 66%, which is about 10% higher than that of ZSM-5. The initial selectivity of the by-product ethylbenzene is decreased significantly to only 0. 25% , and the catalyst lifetime is 180 h. © 2024 Editorial Office of Acta Petrolei Sinica. All rights reserved.