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A method for preparing graphene-based composites based on graphene oxide self-assembly

A graphene-based, composite material technology, applied in the preparation of amino hydroxyl compounds, chemical instruments and methods, preparation of organic compounds, etc., can solve the limitations of functional modification of material properties, poor water dispersibility of graphene-based composite materials, aggregation, etc. problem, to achieve the effect of long-lasting chemical stability and catalytic activity, good application potential, and simple operation method

Active Publication Date: 2016-08-24
芽米科技(广州)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the coating process, the microspheres are often adhered by graphene oxide, resulting in serious aggregation, resulting in poor water dispersibility of the final prepared graphene-based composite material, which greatly limits the variety of materials. Properties and further functional modifications

Method used

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  • A method for preparing graphene-based composites based on graphene oxide self-assembly
  • A method for preparing graphene-based composites based on graphene oxide self-assembly
  • A method for preparing graphene-based composites based on graphene oxide self-assembly

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Embodiment 1: The method provided by the invention is used for the assembly of small-sized graphene oxide sheets on the surface of silica microspheres:

[0036] (1) Mix 100 mL of 0.2 M tetraethyl orthosilicate ethanol solution with 100 mL of ethanol solution containing ammonia (1.6 M) and water (34 M), and stir vigorously overnight. Using ethanol as a solvent, the silica colloidal microspheres generated by the hydrolysis of tetraethylorthosilicate under the catalysis of ammonia were centrifuged repeatedly — Vacuum dry after washing. The as-prepared silica colloidal microspheres were quite uniform in size, with an average diameter of ~280 nm ( figure 2 ).

[0037] (2) Ultrasonic disperse 1 g of the silica microspheres prepared in step (1) in 100 mL of water to form a 10 mg / mL aqueous dispersion; Dimethylammonium chloride was dissolved in 95 mL of water and stirred for more than 1 h. Then mix the silica aqueous dispersion with the polydiallyldimethylammonium chloride...

Embodiment 2

[0044] Embodiment 2: the method provided by the invention is used to prepare the graphene-based composite material with unique structure and high water dispersibility:

[0045] (1) Ultrasonic disperse 0.4 g of the silica / graphene oxide composite microspheres in Example 1 in 100 mL of water to form an aqueous dispersion with a concentration of 4 mg / mL, and mix it with 100 mL of 40 mM Stir and mix the newly prepared silver ammonia solution at 85 o C for 45 min, using the reducing property of graphene oxide itself to reduce the silver ammonium complex into silver nanoparticles in situ and deposit them on the surface of the composite microspheres to prepare a composite of silica / graphene oxide / silver nanoparticles Microspheres. Using water as solvent, it was centrifuged repeatedly — Vacuum dry after washing.

[0046] (2) Ultrasonic disperse 0.2 g of the silica / graphene oxide / silver nanoparticle composite microspheres in step (1) in 100 mL of water to form an aqueous dispersion ...

Embodiment 3

[0052] Embodiment 3: the graphene-based composite material prepared in the present invention is used for the catalytic reduction of 4-nitrophenol:

[0053] (1) Weigh 3 mg of the silica / graphene / silver nanoparticle composite microspheres in Example 2, and ultrasonically disperse them in 20 mL of water to form an aqueous dispersion with a concentration of 0.15 mg / mL, and take 1 mL, and then diluted to an aqueous dispersion with a concentration of 1.5 μg / mL.

[0054] (2) Take 1 mL of the aqueous dispersion diluted in step (1), and mix it successively with 1 mL of 30 mM sodium borohydride aqueous solution and 1 mL of 0.3 mM 4-nitrophenol aqueous solution , and then transfer the reaction mixture to a cuvette for reaction.

[0055] (3) The whole process of the catalytic reaction adopts ultraviolet — Visible spectroscopy was used for in situ monitoring to determine the rate constant of this reaction and to identify the catalytic activity of the as-prepared catalyst (ie, silica / grap...

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Abstract

The invention relates to a self-assembly method of graphene oxide on a non-planar substrate surface and a silica / graphene / silver nanoparticle composite microsphere with a unique raspberry-like structure constructed based on this method, which belongs to graphene-based composites. Technical field of material preparation. First, tetraethyl orthosilicate is used as the silicon source and a slightly modified Söber method is used to prepare silica microspheres. Then a cationic polyelectrolyte is assembled on the surface to positively electrify the surface, and then it is electrostatically charged under continuous powerful ultrasonic conditions. The effect causes small-sized graphene oxide sheets to self-assemble on the surface of the microspheres. Next, silver nanoparticles are deposited in situ on the surface of the composite microspheres, and then the graphene oxide is reduced to graphene with hydrazine hydrate, resulting in a raspberry-like shape. Structured silica / graphene / silver nanoparticle composite microspheres. The composite microspheres have good water dispersibility and show excellent catalytic activity for the catalytic reduction of 4-nitrobenzene, showing broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of preparation of graphene-based composite materials, in particular to a method for self-assembly of graphene oxide on the surface of a non-planar substrate (silicon dioxide microsphere) under the assistance of ultrasound, and a high-water Raspberry-like structured silica / graphene / silver nanoparticles composite microspheres with dispersibility and high catalytic performance. Background technique [0002] Due to its unique structure and excellent physical and chemical properties, graphene has become a hotspot in the field of material research, and various graphene-based composite materials and functional materials have emerged in an endless stream. In previous reports, people often loaded various nanoparticles (such as metal oxides, metal sulfides, noble metals, conductive polymer nanoparticles, etc.) ～ 5 μm) to prepare graphene / nanoparticle composites. In the process of preparing these graphene / nanoparticl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J21/18B01J32/00B01J23/50B01J35/02C07C215/76C07C213/02B01J35/00
CPCC07C213/02B01J21/18B01J23/50B01J35/50B01J35/51C07C215/76
Inventor 肖巍张艳华周文杰
Owner 芽米科技(广州)有限公司
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