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

- Mesoporous Y zeolite with high mesopore volume and total pore volume.
- Mesoporosity can be tuned by varying buffer solution or concentration of base solution.
- Mesopores are well-connected with micropores.
- Defects induce mesopores formation.
- Mesoporous Y zeolite possesses high B/L ratio.

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.

A route of sequential ammonium hexafluorosilicate (AHFS) and base treatment has been designed to prepare Y zeolite with high mesopore volume. Defects generated after AHFS treatment played a crucial role in the whole modification procedure to form rich mesopores.480