Preparation method of core-shell structured Pd-Co/CN@SiO2 nano-catalyst

Abstract

The invention discloses a preparation method of a core-shell structured Pd-Co / CN@SiO2 nano-catalyst. The method comprises the following steps: mixing and reacting cobalt nitrate hexahydrate, potassiumchloropalladate and 2-methylimidazole to prepare a palladium-supported cobalt-based metal organic framework Pd<2+> / ZIF-67, then reacting the Pd<2+> / ZIF-67 with 2-methylimidazole, cetyltrimethylammonium chloride and tetraethyl orthosilicate to make the surface of the Pd<2+> / ZIF-67 wrapped with silica, and performing calcination to obtain the Pd-Co / CN@SiO2 catalyst. SiO2 shell coating can effectively prevent the agglomeration of Pd-Co nanoparticles and prevent the loss of metal particles in a catalytic reaction, so the catalytic activity is improved, and the hydrogenation reduction of nitro compounds under normal temperature and normal pressure conditions is realized; the method has the advantages of mild conditions, strong practicability, and easiness in operation; and the catalyst has theadvantage of magnetism, easiness in recovery, and realization of cycle use.

Description

technical field [0001] The invention belongs to the technical field of nanometer metal catalysts, and relates to a core-shell structure Pd-Co / CN@SiO 2 Preparation methods of nanocatalysts. Background technique [0002] As important chemical intermediates, substituted amino compounds are widely used in the synthesis of drugs, pesticides, organic pigments, coatings, polymers, etc. They are generally prepared by reducing the corresponding nitro compounds. Currently commonly used reduction methods are: iron powder or alkali sulfide reduction method, sodium borohydride, hydrazine hydrate, formic acid, hydrogenation reduction method, etc. A large amount of three wastes will be produced in the reduction process of iron powder or alkali sulfide, causing serious environmental pollution and serious corrosion to equipment. When sodium borohydride, hydrazine hydrate, and formic acid are used as reducing agents, although these reducing agents have good selectivity, they often have the...

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Problems solved by technology

X. Sun et al. (Journal of Catalysis 357 (2018) 20–28) reported a cobalt nano-dispersed material on porous nitrogen-doped graphite, Co@mesoNC, which has good catalytic system for various nitro-containing compounds. Catalytic activity, but it needs to be transformed at 383K, 3MPa

Eckardt M et al. (Scientific Reports, 2018, 8(1)) prepared a nitrogen-doped graphite material with active cobalt nanoparticles. The catalyst can selectively reduce a variety of nitro compounds to amino compounds, but it also It requires higher temperature and pressure (363K and 4MPa), which has higher requirements on equipment, which is not conducive to industrial production, and there are problems of easy sintering and loss of metal nanometers

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