High-silica zeolite Y: seed-assisted synthesis, characterization and catalytic properties

Abstract

A facile solid seed assisted strategy has been developed for the synthesis of high silica zeolite Y. The crystal growth kinetics as a function of seed usage were studied, showing a positive relationship with the seed addition. A smaller seed size and higher seed SAR were found to be favorable for the crystallization of high silica zeolite Y. FTIR spectra revealed that the acidic hydroxyls in small SOD cages of high silica zeolite Y can transfer to supercages under the induction of pyridine, while this phenomenon is inconspicuous for conventional zeolite Y, which suggests the incremental utilization of the acid sites in the SOD cages following the increase of framework SAR. The high silica S-SY product possesses a larger amount of acid sites, higher acid strength and excellent (hydro)thermal stability, and thus exhibits higher catalytic cracking activity for model molecules and industrial heavy oil, which imply its promising future as a cracking catalyst for bulky hydrocarbons.