Constructing Intrapenetrated Hierarchical Zeolites with Highly Complete Framework via Protozeolite Seeding

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Microporous zeolites offer high selectivity but suffer from poor molecular transport.
• Hierarchical zeolites with mesopores improve diffusion and active site accessibility.
• Existing methods for creating mesopores in zeolites often result in isolated pores.

Purpose of the Study:

• To synthesize single-crystalline hierarchical ZSM-5 zeolites with intrapenetrated mesopores.
• To improve molecular transport and catalytic activity by creating accessible pore networks.
• To develop a facile and effective strategy for hierarchical zeolite synthesis.

Main Methods:

• Utilized nanosized amorphous protozeolites as seeds for zeolite crystallization.
• Employed a synthesis strategy with minimal organic structure-directing agents and low crystallization temperature.
• Observed oriented coalescence of crystallites to form intrapenetrated mesopores.

Main Results:

• Achieved hierarchical ZSM-5 zeolites with a high mesopore volume (0.51 cm³ g⁻¹).
• Demonstrated ultra-long catalyst lifetime (443.9 hours) in the methanol-to-propylene reaction.
• Obtained high propylene selectivity (47.92%) at a WHSV of 2 h⁻¹.

Conclusions:

• The protozeolite-seeded strategy successfully created intrapenetrated hierarchical zeolites.
• The synthesized zeolites exhibit superior catalytic performance due to enhanced pore structure.
• This method offers a promising route for designing advanced zeolite catalysts.