Defects in AHFS-dealuminated Y zeolite: A crucial factor for mesopores formation in the following base treatment procedure

Abstract

Mesoporous zeolites have gained a great interest because of their improved performance in catalyzed reactions compared with conventional microporous zeolites. Herein, we would like to report a strategy containing sequential ammonium hexafluorosilicate (AHFS) and base treatment to prepare mesoporous Y zeolite. The obtained mesoporous Y zeolite possessed high total pore volume (0.720 cm3 g−1) and mesopore volume (0.453 cm3 g−1). Furthermore, the goal of well interconnectivity among different pores has also been achieved. It has been found that AHFS treatment played a crucial role in the formation of mesopores during the following base treatment procedure. Si-rich areas, which were full of defects, formed after AHFS treatment. These areas were unstable and easy to remove from the zeolite framework in base solution to generate mesopores. Meanwhile, the defects provided paths for base treatment and made it more effective. The combined treatment achieved a goal of inducing mesopores formation by defects. Catalytic performance of the zeolites were evaluated by cracking of 1,3,5-triisopropylbenzene (TIPB). The result showed that catalytic activity was closely related to the upgraded mesoporosity system of the zeolites.