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Three industrially modified Y zeolites with a hierarchical structure were characterized by XRD, N2 adsorption–desorption, SEM, TEM, 27Al-/29Si-NMR, in situ pyridine-FTIR, and NH3-TPD techniques. The industrial hydrocracking catalyst of light diesel oil was prepared by kneading and extruding the mixture of 10 wt.% industrially modified zeolite, commercial alumina, nickel nitrate, and molybdenum oxide. The small amount of hierarchical Y zeolite in the hydrocracking catalyst plays a key role, resulting in selective hydrogenation of naphthalene and further ring-opening activity. The mesoporous structure of the zeolites provided an effective interface and improved the accessibility of acid sites to bulky reactants. [ABSTRACT FROM AUTHOR]

In the hydrocracking of 9, 10-dihydroanthracene, acid sites and their locations in the Y zeolites play crucial roles. Hydrogen transfer is the dominant reaction for the industrial Y zeolites with undeveloped mesopores whether at low or high temperatures. Those with developed mesopores exhibit enhanced ring-opening and cracking ability due to the improved molecular transport and accessibility of acid sites. Their ring-opening and cracking ability is crucially related to the amount of highly strong Brønsted acid sites in the high-silica Y zeolites. The reaction processes of 9, 10-dihydroanthracene hydrocracking over the industrial Y zeolites with different properties were expounded rationally. • 9, 10-DHA on various Y zeolites follows the different hydrocracking routes. • Highly strong B acid formed in supercage is key to ring-opening and cracking. • Enhanced acidic accessibility by mesopores promote the ring-opening and cracking. • Acidic and textural properties show synergetic effects on the hydrocracking. • The acidic and textural properties of Y zeolites affect the activation to H 2. [ABSTRACT FROM AUTHOR]

Zeolite–zeolite composites composed of Y zeolite cores and polycrystalline β zeolite shells were prepared, in which Y zeolite was overgrown with a thin layer of nano-β zeolite. The incompatibility of the cores and the shells with different zeolite structure types, chemical compositions and crystallization conditions was circumvented by using Y zeolite as the nutrients for the growth of β zeolite crystals since the dissolution of the core zeolites was inevitable during the formation of the shell layers. The structural, crystalline, and textural properties of the as-synthesized samples were characterized by XRD, SEM, TEM, EDS, SAED, N 2 adsorption–desorption, FT-IR, in situ IR spectra of pyridine and di -tert-butyl pyridine. The performances of the as-synthesized zeolite–zeolite composite supported by Ni–Mo active components were investigated during the hydrocracking of Iran VGO oil. The results displayed that the core–shell structured composites with a high-silicon β zeolite shell displayed a better performance in terms of conversion of VGO oil and yield of jet fuel, middle distillate yields and middle distillate selectivity than the reference catalyst and the composite catalyst with a low-silicon β zeolite shell. [ABSTRACT FROM AUTHOR]