Hierarchical pore composites are the hotspots in the research of porous catalytic materials in recent years

Hierarchical pore composites, especially the composites of mesopores and micropores, are the hotspots in the research of porous catalytic materials in recent years.

Porous materials all have shortcomings such as poor thermal stability of materials, lack of surface acid centers with a certain strength and easy loss of acid centers.

The reason is that although the above materials have ordered mesoporous channels, their framework is amorphous. Although zeolite molecular sieves have good structural stability

Qualitative and strong acidic center, but there is the limitation of molecular diffusion, which affects the activity and selectivity of its catalytic reaction. While micropores and mesopores or macroporous hierarchical porous composite materials are expected to combine the advantages of both and exert their advantages in practical applications. In recent years, hierarchical porous composite molecular sieves have been become a research hotspot.

It has become a research hotspot. Its synthesis method is mainly to add nanocarbon black, carbon nanotubes, starch, nano-carbon into the synthesis system of zeolite.

Calcium carbonate, macromolecules (PDDA, PVB, etc.) and quaternary ammonium cationic silicone surfactants, etc., make them compatible with small fractions

During the growth of zeolite crystals, the sub-organic amine templates work together to encapsulate the zeolite crystals, and finally remove these templates by calcination.

The formation of mesopores in zeolite crystals. In addition, some mesopores with crystalline pore walls can also be synthesized by the method of mesoporous or macroporous amorphous walls.

Hierarchical pore composite zeolite molecular sieves in supercritical toluene disproportionation , gas phase alkylation of ethylene and benzene  and heavy aromatic transalkylation showed good catalytic performance in other reactions.

Recently, the gas phase crystallization method to synthesize mesoporous-macroporous silica-alumina molecular sieves by transcrystallization.

The hierarchically porous Beta molecular sieve was obtained, and it was found that it has good catalytic performance in the liquid-phase transalkylation reaction between benzene and dicumylbenzene.

Therefore, hierarchical pore zeolite molecular sieves are expected to be used in some larger molecular catalytic reactions and liquid-phase catalytic reactions.