A bifunctional catalyst of a sodium-free silica-alumina molecular sieve encapsulating metal nanoparticles and a preparation method thereof

Abstract

The present invention relates to a bifunctional catalyst of a sodium-free aluminosilicate acidic molecular sieve encapsulating metal nanoparticles and a preparation method thereof. The bifunctional catalyst is added with a metal precursor during the in-situ synthesis process of a sodium-free aluminosilicate acidic molecular sieve. Utilize the "one-step method" to realize the encapsulation of metal nanoparticles by sodium-free silica-alumina acidic molecular sieve, and obtain a dual-functional catalyst with both metal hydrogenation / dehydrogenation function and molecular sieve acid catalytic function; the metal content in the dual-functional catalyst is 0.1-10wt %, the distribution of metal nanoparticles is uniform, the particle size is uniform, and the size is 1-10nm.

Description

technical field [0001] The present invention relates to the field of catalysts, in particular to a dual-functional catalyst and a preparation method of a sodium-free silico-alumino acidic molecular sieve encapsulating metal nanoparticles, to be precise, to an encapsulating non-precious metal Ni, Co, Cu, Fe, Mo , Zn, Mn, Cr, etc. at least one kind of nano-particle sodium-free aluminosilicate acidic molecular sieve dual-function catalyst and preparation method, and a dual-function catalyst with metal hydrogenation / dehydrogenation function and molecular sieve acid catalysis function. Background technique [0002] Catalysis is the core technology in the chemical and chemical production process, and catalyst is the soul of the entire catalytic technology. Metal particles are generally the key active components in reactions such as hydrogenation, oxidation, and dehydrogenation; molecular sieves, as a type of inorganic porous material, are the most widely used catalytic materials i...

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Problems solved by technology

[0006] CN 107020147A (2017) discloses a MFI structure sheet molecular sieve catalyst, preparation method and application of encapsulating metal oxides or metal nanoparticles. First, a sheet MFI structure molecular sieve is synthesized, and then a silicon support column is used to support a sheet MFI structure molecular sieve And the metal oxide or metal nanoparticles are encapsulated between the sheets, which is equivalent to the method of post-treatment modification to realize the MFI structure molecular sieve encapsulation of metal oxide or metal nanoparticles, and the content of metal oxide in the entire catalyst is 0.1 ~5wt%; in addition, the method requires many steps and long crystallization time

[0007] However, the above work on encapsulating metals with molecular sieves only uses the structural characteristics of molecular sieves to achieve encapsulation of metals, and does not involve the acid catalytic function of molecular sieves. The synthesized molecular sieves do not have acid catalytic functions and cannot be realized.

Moreover, the currently reported patents and documents are more focused on molecular sieve encapsulation of noble metal catalysts, the process is complicated and there are many steps

As future industrial catalysts, non-noble metals such as Ni, Co, and Fe will have more competitive advantages, but there are still limited reports on encapsulating non-noble metal catalysts, especially the dispersion of metal Ni particles is a very difficult challenge

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