ZSM-5 hybrid nanosheet molecular sieve with medium silica-alumina ratio and preparation method thereof

Abstract

The invention discloses a ZSM-5 hybrid nanosheet molecular sieve with a medium silica-alumina ratio and a preparation method thereof, and belongs to the technical field of catalysts. The hybrid molecular sieve is composed of an internal microporous substrate and a nanosheet layer epitaxially growing outside the microporous substrate, the silica-alumina ratio range of the hybrid molecular sieve is adjustable in a range of 100-300, and the preparation method specifically comprises the following steps: 1) dissolving a micromolecule template agent, a silicon source and an aluminum source in water, and uniformly stirring to form gel; 2) aging under a stirring condition; (3) continuously adding a long-carbon-chain amphiphilic surfactant solution and uniformly stirring; 4) aging under the stirring condition; and 5) crystallizing to obtain the hybrid ZSM-5 molecular sieve. The preparation method solves the problem that the morphology of the molecular sieve is limited by the silica-alumina ratio of the nanosheet-block hybrid molecular sieve synthesized at the present stage, and breaks through the limitation that the growth of the outer nanosheet cannot be maintained if the silica-alumina ratio is reduced, and the prepared hybrid molecular sieve has great application prospects in the catalytic fields of preparation of low-carbon olefins and the like.

Description

technical field [0001] The invention belongs to the field of catalysts, and particularly relates to a ZSM-5 hybrid nanosheet molecular sieve with a medium silicon-aluminum ratio and a preparation method thereof. The molecular sieve can be used as a catalyst for the preparation of low-carbon olefins, and has good low-carbon olefin selectivity and resistance Carbon deposition performance. Background technique [0002] Hierarchical molecular sieves combine the acid catalytic performance of microporous molecular sieves with the diffusion and mass transfer characteristics of mesopores or macropores. The introduction of mesopores improves the coking resistance of traditional microporous catalysts, making them widely used in the chemical industry prospect. The key to synthesizing hierarchically porous molecular sieves with good catalytic performance lies in the balance between acid catalytic function and mesopore size. [0003] At present, the methods for synthesizing hierarchica...

AI Technical Summary

Problems solved by technology

However, the presence of aluminum hinders the growth of nanosheets

At present, the dual-template method can only synthesize ZSM-5 hybrid nanosheet molecular sieves with a silicon-aluminum ratio higher than 300, which greatly limits its application in acid-catalyzed reactions.

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