Molecular sieve packaged core-shell catalyst and preparation method thereof

Abstract

The invention discloses a molecular sieve packaged core-shell catalyst (Figure 1) and a preparation method thereof, and relates to the field of catalyst preparation. According to the core-shell catalyst, an inner core is CuPt / SSZ-39, a shell is hierarchical pore Silicalite-1, the catalyst is prepared from CuPt / SSZ-39, a silicon source and a quaternary ammonium salt structure-directing agent through a hydrothermal synthesis method, and the inner core is prepared by dipping an SSZ-39 molecular sieve in a CuPt bimetallic precursor solution; the modified SSZ-39 molecular sieve is prepared by modifying an SSZ-39 molecular sieve with a silane coupling agent. The CuPt bimetallic nanoparticles in the catalyst prepared by the invention are anchored on the surface of the modified SSZ-39 molecular sieve and encapsulated in the shell of the hierarchical pore Silicalite-1 molecular sieve, so that the activity and sintering resistance of the catalyst are remarkably improved, and the catalyst can be applied to the fields of petrochemical engineering, fine chemical engineering and the like.

Description

technical field [0001] The invention relates to the technical field of catalysts, in particular to a core-shell catalyst encapsulated by a molecular sieve and a preparation method thereof. Background technique [0002] Bimetallic nanoparticles exhibit desired activities in various catalytic reactions. The size and dispersion of bimetallic nanoparticles have an important influence on the catalytic performance of bimetallic nanocatalytic materials. The smaller the size of bimetallic nanoparticles, the higher the dispersion. , the better the catalytic activity. However, the aggregation and sintering of metal nanoparticles often lead to the loss of catalytic performance during the actual reaction process. At the same time, due to the lack of effective regulation of the reaction site, it is difficult to effectively control the catalytic reaction pathway, which inevitably leads to the occurrence of side reactions such as carbon deposition, which leads to the decrease of the selec...

AI Technical Summary

Problems solved by technology

[0006] In the present invention, a multi-level pore pure silicon molecular sieve is used to replace the traditional silicon-aluminum molecular sieve to prepare a core-shell catalyst. The inner core can be used as a carrier to uniformly anchor metal nanoparticles, and the outer shell can act as a physical barrier to inhibit the loss of metal nanoparticles. The composite catalyst with multi-level pore structure solves the problems that the skeleton of the molecular sieve is easy to collapse during the reaction process, thus destroying the pore structure of the molecular sieve, difficult molecular dynamics diffusion of reaction molecules and products, poor metal dispersion and short catalyst life.

Images