Hierarchical pore molecular sieve packaged platinum-nickel bimetallic nano catalytic material as well as preparation method and application thereof

Abstract

The invention discloses a hierarchical pore molecular sieve packaged platinum-nickel bimetallic nano catalytic material and a preparation method and application thereof. The catalytic material is prepared from a modified silicon source, an aluminum source, a quaternary ammonium salt structure-directing agent and a PtNi bimetallic precursor through a hydrothermal synthesis method, and the modified silicon source is prepared by modifying nano silicon dioxide through a silane coupling agent. The PtNi bimetallic precursor is prepared by electrostatic self-assembly of an amine structure directing agent, Pt and Ni sources, and based on the total mass of the catalytic material, the mass percent of nickel is 0.1-20wt%, and the mass percent of platinum is 0.1-5wt%. A one-step method is adopted, a PtNi bimetallic precursor is introduced in situ in the process of synthesizing the hierarchical pore molecular sieve, and selective packaging of the PtNi bimetallic nanocluster in a hierarchical pore molecular sieve side cage is achieved. The catalytic material is applied to a reaction for catalyzing dehydrogenation coupling of pyridine to synthesize 2,2'-dipyridyl, has the advantages of low dosage, few side reactions, short process and the like, and has a good application prospect in the fields of adsorption separation, petrochemical engineering, fine chemical production and the like.

Description

technical field [0001] The invention belongs to an industrial catalytic material and a preparation method thereof, in particular to a platinum-nickel double-metal nano-catalysis material encapsulated by a multi-stage molecular sieve, a preparation method and an application thereof. Background technique [0002] Due to its high catalytic activity and selectivity, PtNi bimetallic nanocatalytic materials are widely used in reactions such as alkane dehydrogenation, automobile exhaust gas conversion, methane reforming, and electrocatalytic hydrogen evolution. The catalytic performance of bimetallic nanocatalytic materials has an important influence. The smaller the size and the higher the dispersion of PtNi bimetallic nanoparticles, the better the catalytic activity. However, due to the high surface energy of PtNi bimetallic nanoparticles, it is difficult for PtNi bimetallic particles to maintain their original structure and morphology during catalytic reactions, especially in hi...

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Problems solved by technology

[0004] At present, there are many technologies for encapsulating bimetallic catalysts with molecular sieves. Chinese patent CN112044467A discloses a method of mixing and crystallizing molecular sieve seeds and nanometer metal sources to prepare any two metals in Cu, Ti, Ni, and Fe as active components. The preparation method of bimetallic MFI molecular sieves with molecular sieves as the carrier realizes the doping and encapsulation of bimetals in the molecular sieve framework, but the distribution position of the bimetals in the molecular sieve framework and cage lacks effective control, and the catalyst is easily caused by the bimetallic during the reaction process. Sintering and loss inactivation of active components; Chinese patent CN107661776A discloses a method for preparing SAPO molecular sieves containing Cu and Ag bimetals by ion exchange, and the prepared SAPO molecular sieves containing Cu and Ag bimetals have better hydrothermal stability However, during the high-temperature catalytic reaction, Cu and Ag bimetals are easy to lose and agglomerate

Most of the reported molecular sieve-supported bimetallic catalysts are prepared by the ion exchange method, which lacks the control of the distribution of the bimetallic on the molecular sieve, and the bimetallic active center is easy to agglomerate and lose, and the stability is poor.

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