Preparation method and catalytic application of Silicalite-1 single crystal-coated nanopalladium-loaded core-shell catalyst

A technology of core-shell catalysts and nano-palladium, which is applied in the direction of molecular sieve catalysts, chemical instruments and methods, physical/chemical process catalysts, etc., can solve the problems of unfavorable catalyst catalytic activity, poor catalyst monodispersity, and labor-intensive and material resources. Uniform particle distribution, solving the effect of poor monodispersity and high temperature aggregation resistance to metal loss

Active Publication Date: 2017-12-08
DALIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above methods have disadvantages such as poor monodispersity of the catalyst, need for multiple roasting, and long time-consuming crystallization or secondar

Method used

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  • Preparation method and catalytic application of Silicalite-1 single crystal-coated nanopalladium-loaded core-shell catalyst
  • Preparation method and catalytic application of Silicalite-1 single crystal-coated nanopalladium-loaded core-shell catalyst
  • Preparation method and catalytic application of Silicalite-1 single crystal-coated nanopalladium-loaded core-shell catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Preparation of Sil-1 nano-seeds

[0030] According to TPAOH:TEOS:H 2 The molar ratio of O=0.25:1:27, first measure 48.6 mL of deionized water, and add 23.85 mL of tetrapropylammonium hydroxide (TPAOH) under vigorous stirring. Keep stirring vigorously for 30min. Then, 22.7 mL of ethyl orthosilicate was added dropwise at a rate of 1 mL / min. After the dropwise addition was completed, it was stirred and aged for 24 h at room temperature. Put it into a synthesis kettle lined with polytetrafluoroethylene, and hydrothermally synthesize it in a static oven at 90°C for 18h. After the synthesis was completed, the product was taken out, washed by centrifugation and dispersed in ethanol to prepare an ethanol suspension with a seed crystal density of 0.018 g / mL. The morphology of the Sil-1 seed crystal is as follows figure 1 Shown, XRD as Figure 4 shown.

[0031] (2) Amino-modified Sil-1 nano-seeds and their interaction with Pd 2+ solid-load combination

[0032] Take 3...

Embodiment 2

[0040] (1) The preparation of Sil-1 nano-crystal seeds is the same as that in Example 1.

[0041] (2) Amino-modified Sil-1 nano-seeds and their interaction with Pd 2+ solid-load combination

[0042] Take 4 mL of the seed crystal suspension in step (1), add ethanol to 20 mL, and add 335 μL of 3-aminopropyltriethoxysilane with 2% mass of the above solution, heat treatment in a water bath at 60° C., and stir for 6 h. The sample was washed twice with deionized water and dispersed in 6 mL of deionized water to form a homogeneously dispersed amino-modified Sil-1 seed crystal suspension. Take 0.003gNa 2 PdCl 4 The solid powder was dissolved in 4 mL of deionized water, and the solution was added dropwise to the above amino-modified Sil-1 seed crystal suspension. After the dropwise addition, the mixture was stirred in a water bath at 30° C. for 2 h to obtain a Pd / Sil-1 supported catalyst.

[0043] (3) Synthesis of Pd@Sil-1 core-shell catalyst

[0044] According to TEOS:TPAOH:H 2...

Embodiment 3

[0047] (1) The preparation of Sil-1 nano-crystal seeds is the same as that in Example 1.

[0048] (2) Amino-modified Sil-1 nano-seeds and their interaction with Pd 2+ solid-load combination

[0049] Take 5 mL of the seed crystal suspension in step (1), add ethanol to 20 mL, and add 335 μL of 3-aminopropyltriethoxysilane with a mass of 2% of the above solution, heat treatment in a water bath at 60° C., and stir for 6 h. The sample was washed twice with deionized water and dispersed in 6 mL of deionized water to form a homogeneously dispersed amino-modified Sil-1 seed crystal suspension. Take 0.005gNa 2 PdCl 4 The solid powder was dissolved in 4 mL of deionized water, and the solution was added dropwise to the above amino-modified Sil-1 seed crystal suspension. After the dropwise addition, the mixture was stirred in a water bath at 30° C. for 2 h to obtain a Pd / Sil-1 supported catalyst.

[0050] (3) Synthesis of Pd@Sil-1 core-shell catalyst

[0051] According to TEOS:TPAOH...

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Abstract

The invention discloses a preparation method and catalytic application of a Silicalite-1 single crystal-coated nanopalladium-loaded core-shell catalyst, and belongs to the field of novel catalytic materials. The preparation method comprises the following steps: under the hydroxyl action between 3-aminopropyl triethoxysilane and the surfaces of Silicalite-1 molecular sieve nanocrystals, modifying amino groups onto the surfaces of the molecular sieve nanocrystals; then, through coordination and complexation actions between the Pd<2+> and the amino groups modified on the outer surfaces of the Silicalite-1, uniformly and fixedly loading the Pd<2+> onto the surface of a nanocrystal molecular sieve to form the palladium-loaded nanocrystals Pd/Silicalite-1; finally, adding the Pd/Silicalite-1 nanocrystals into a synthesis solution of Silicalite-1 molecular sieve single crystals, and synthesizing the Pd@Silicalie-1 single crystal-coated core-shell catalyst via induced growth. By the preparation method, preparation is simple and high in efficiency, and the defects that the conventional catalyst is poor in monodispersity, is required to be roasted for multiple times and takes a long time for crystallizing or posttreating a sample are overcome. Compared with the traditional homogeneous catalyst, the core-shell catalyst has the characteristics of excellent shape selectivity, metal loss resistance, high temperature aggregation resistance and the like, so that the core-shell catalyst has a wide application prospect.

Description

technical field [0001] The invention belongs to the field of novel catalytic materials, in particular to a method for preparing an amino-modified nano Silicalite-1 (Sil-1) seed crystal to adsorb palladium ions and induce growth to form a Sil-1 molecular sieve single crystal coated nano-palladium structure core-shell catalyst and its application in catalytic hydrogenation. Background technique [0002] Zeolites are an important class of porous inorganic crystalline materials with a wide variety. Due to their rich framework topology and elemental composition, zeolite molecular sieves have been widely used in the fields of ion exchange, adsorption separation, and catalysis since they can be synthesized artificially. Coating functional nanomaterials inside zeolite molecular sieve grains can effectively solve the problems of high-temperature agglomeration, loss, and poisoning of nanomaterials, and reflect the shape-selective function of molecular sieves. [0003] Slicalite-1 pu...

Claims

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Application Information

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IPC IPC(8): B01J29/03C07C5/03C07C9/15C07C13/18C07C13/26
Inventor 张雄福刘存刘海鸥
Owner DALIAN UNIV OF TECH
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