Method for preparing selectivity-adjustable efficient supported precious-metal core-shell catalyst coated with metal-organic framework ZIF-8 membrane

A technology of noble metal catalysts and metal-organic frameworks, applied in organic compound/hydride/coordination complex catalysts, chemical instruments and methods, physical/chemical process catalysts, etc., to achieve high selectivity and wide application prospects

Inactive Publication Date: 2014-07-09
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved in the present invention is a new type of core-shell catalyst obtained by coating heterogeneously loaded noble metal microspheres with ZIF-8 membrane to address the disadvantages of the current preparation of heterogeneous catalysts.

Method used

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  • Method for preparing selectivity-adjustable efficient supported precious-metal core-shell catalyst coated with metal-organic framework ZIF-8 membrane
  • Method for preparing selectivity-adjustable efficient supported precious-metal core-shell catalyst coated with metal-organic framework ZIF-8 membrane
  • Method for preparing selectivity-adjustable efficient supported precious-metal core-shell catalyst coated with metal-organic framework ZIF-8 membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Preparation of Pd nanoparticles

[0030] First prepare 2mM H 2 PdCl 4 aqueous solution, and then with PVP, H 2 After O and HCl are mixed, heat to boiling, add ethanol immediately, and reflux for 3h;

[0031] (2) SiO 2 Preparation of vector

[0032] According to stober method, using TEOS as silicon source, NH 4 OH is used as a catalyst, and it is hydrolyzed at room temperature for 1 hour under the mixed system of ethanol / water;

[0033] (3) Combine the Pd nanoparticles obtained by method (1) with the SiO obtained by method (2) 2 Mix at room temperature for 24 hours to obtain Pd / SiO 2 catalyst;

[0034] (4) Pd / SiO obtained by method (3) 2 Mix the aqueous solution with the PDDA aqueous solution, let it stand at room temperature for 30 minutes, and then centrifugally wash it with deionized water for several times; then mix it with the PSS aqueous solution at room temperature for 30 minutes, and then centrifugally wash it with deionized water and methanol for seve...

Embodiment 2

[0038] (1) Preparation of Pd nanoparticles

[0039] First prepare 2mM H 2 PdCl 4 aqueous solution, and then with PVP, H 2 After O and HCl are mixed, heat to boiling, add ethanol immediately, and reflux for 3h;

[0040] (2) SiO 2 Preparation of vector

[0041] According to stober method, using TEOS as silicon source, NH 4 OH is used as a catalyst, and it is hydrolyzed at room temperature for 1 hour under the mixed system of ethanol / water;

[0042] (3) Combine the Pd nanoparticles obtained by method (1) with the SiO obtained by method (2) 2 Mix at room temperature for 24 hours to obtain Pd / SiO 2 catalyst;

[0043] (4) The catalyst obtained in method (3) was vacuum-dried overnight at 80°C and placed in a desiccator for testing.

Embodiment 3

[0045] (1) Preparation of Pd nanoparticles

[0046] First prepare 2mM H 2 PdCl 4 aqueous solution, and then with PVP, H 2 After O and HCl are mixed, heat to boiling, add ethanol immediately, and reflux for 3h;

[0047] (2) SiO 2 Preparation of vector

[0048] According to stober method, using TEOS as silicon source, NH 4 OH is used as a catalyst, and it is hydrolyzed at room temperature for 1 hour under the mixed system of ethanol / water;

[0049] (3) Combine the Pd nanoparticles obtained by method (1) with the SiO obtained by method (2) 2 Mix at room temperature for 24 hours to obtain Pd / SiO 2 catalyst;

[0050] (4) Pd / SiO obtained by method (3) 2 Mix the aqueous solution with the PDDA aqueous solution, let it stand at room temperature for 30 minutes, and then centrifugally wash it with deionized water for several times; then mix it with the PSS aqueous solution at room temperature for 30 minutes, and then centrifugally wash it with deionized water and methanol for se...

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Abstract

The invention relates to a method for preparing a selectivity-adjustable efficient supported precious-metal core-shell catalyst coated with a metal-organic framework ZIF-8 membrane, and belongs to the technical field of new materials. The method comprises the following steps: coating a pre-prepared supported precious-metal catalyst with a ZIF-8 membrane selective-separation layer, repairing the defect of the membrane layer through polyelectrolyte, adjusting and controlling the membrane forming times to obtain continuous ZIF-8 membranes with different compactnesses, and thereby the catalyst has the adjustable high selectivity. Compared with the same kind of catalyst, the selectivity-adjustable efficient supported precious-metal core-shell catalyst has the advantages of simple preparation process, mild conditions and easiness in large-scale amplification. The selectivity-adjustable efficient supported precious-metal core-shell catalyst solves the problem that a multiphase supported precious-metal catalyst has the low selectivity to reactants and products, and simultaneously is beneficial to relieve the fact that active components of the multiphase supported precious-metal catalyst are easily lost and poisoned.

Description

technical field [0001] The invention prepares a selectivity-adjustable metal-organic framework ZIF-8 film-coated loaded noble metal high-efficiency core-shell catalyst. The main reason is that by coating a ZIF-8 membrane with molecular sieving function, the supported noble metal catalyst has high selectivity to reactants and products; at the same time, it also helps to solve the problem that the active components of heterogeneous catalysts are easy to lose and poison during the reaction. , leading to a problem of reduced activity. Background technique [0002] Nanoscale noble metal (Pd, Pt, Au, etc.) catalysts have high catalytic activity in important industrial reactions such as catalytic hydrogenation, selective oxidation, carbon monoxide conversion, and carbon-carbon coupling. Early studies focused on homogeneous systems. Although homogeneous catalysts can provide ideal activity, their recovery and separation problems restrict their application in industrial production. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J31/22
Inventor 张雄福林露张通刘海鸥邱介山
Owner DALIAN UNIV OF TECH
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