A kind of preparation method of egg yolk-eggshell structure composite material

A composite material and eggshell technology, which is applied in the field of nanomaterials, can solve the problems of reduced catalytic efficiency, easy agglomeration and deformation, and reduced catalytic activity, and achieve the effects of recycling and recycling, good magnetic separation effect, and high saturation magnetic susceptibility

Active Publication Date: 2019-06-21
YANGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, small-sized noble metal nanoparticles have relatively high surface energy, which leads to easy agglomeration and deformation, thus losing catalytic activity and selectivity.
[0003] Combining noble metal nanocatalysts with mesoporous SiO 2 Composite formation of egg yolk-eggshell structure is a common method to effectively solve the aggregation of noble metal nanocatalysts, but compared with bare noble metal nanocatalysts, the introduction of the shell will delay the contact between the reaction reagent and the catalyst, resulting in a decrease in catalytic efficiency; the introduction of superparamagnetic Fe 3 o 4 Microspheres as magnetic cores are the most common method to improve the separation efficiency of noble metal nanocatalysts, but at the same time, the nanochannels of the mesoporous shell will be blocked inside, which is not conducive to the diffusion and concentration of reagents, resulting in reduced catalytic activity.
In addition, Fe 3 o 4 The synergistic effect between noble metal particles and noble metal particles has not been fully utilized to improve the catalytic activity of noble metal particles

Method used

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  • A kind of preparation method of egg yolk-eggshell structure composite material
  • A kind of preparation method of egg yolk-eggshell structure composite material
  • A kind of preparation method of egg yolk-eggshell structure composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] (1) Hydrophobic Fe 3 o 4 Preparation of:

[0042] Weigh 0.9 g iron oleate, 0.156 g oleic acid, and 5 g 1-octadecene into a 50 mL three-neck flask, heat to 320 °C (at a heating rate of 18 °C / min), react for 1 h, and then quickly cool to room temperature After the reaction, the solid phase was washed three times with a mixed detergent of acetone and n-hexane to obtain about 0.2 g of ferric oxide particles coated with oleic acid on the surface.

[0043] Take 0.2 g of ferric oxide particles coated with oleic acid on the surface and disperse them in 72 mL of tetrahydrofuran to form Fe 3 o 4 dispersion in tetrahydrofuran.

[0044] (2) Hydrophobic Fe 3 o 4 Surface modification of:

[0045] Disperse 0.05 g DHCA into 6 mL THF, and add 6 mL Fe 3 o 4 The tetrahydrofuran dispersion was heated at 50°C for 3 h, cooled to room temperature and then added with 0.5 mL of NaOH aqueous solution with a concentration of 0.1 mol / L. After centrifugation, the solid was dispersed into 2...

Embodiment 2

[0057] (1) Hydrophobic Fe 3 o 4 preparation of

[0058] Same as the method of Example 1.

[0059] (2) Hydrophobic Fe 3 o 4 surface modification of

[0060] Same as the method of Example 1.

[0061] (3) Au@SiO2 2 Preparation and surface modification of core-shell materials

[0062] Same as the method of Example 1.

[0063] (4) Au@Fe 3 o 4 @m-SiO 2 Preparation of egg yolk-eggshell structure catalyst

[0064] The above prepared Au@SiO 2 Prepare a solution of 1 mg / mL, adjust the pH to 4 with NaOH solution and dilute hydrochloric acid, then add 18 mL of SiO 2 Dispersion, 9 mL of DHCA-Fe prepared by the method above 3 o 4 Water dispersion, stirred at room temperature for 4h.

[0065] After washing three times with water, disperse in 10 mL water, then add 300 mg CTAB, 6 mL ethanol, 48 μL TEOS and 120 μL ammonia water, stir and react for 3-4 h, then wash the solid phase with deionized water and absolute ethanol respectively After three times, add 4 mL of water and 84....

Embodiment 3

[0069] (1) Hydrophobic Fe 3 o 4 preparation of

[0070] Same as the method of Example 1.

[0071] (2) Hydrophobic Fe 3 o 4 surface modification of

[0072] Same as the method of Example 1.

[0073] (3) Au@SiO2 2 Preparation and surface modification of core-shell materials

[0074] Same as the method of Example 1.

[0075] (4) Au@Fe 3 o 4 @m-SiO 2 Preparation of egg yolk-eggshell structure catalyst

[0076] The above prepared Au@SiO 2 Prepare a solution of 1 mg / mL, adjust the pH to 4 with NaOH solution and dilute hydrochloric acid, then add 18 mL of SiO 2 Water dispersion, 9 mL of DHCA-Fe prepared by the above method 3 o 4 Water dispersion, stirred at room temperature for 4h.

[0077]After washing three times with water, disperse in 10 mL water, then add 300 mg CTAB, 6 mL ethanol, 27 μL TEOS and 120 μL ammonia water, stir and react for 3-4 h, then wash the solid phase for three times with deionized water and absolute ethanol respectively. Add 4 mL of water and ...

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Abstract

A preparation method of an egg yolk-eggshell structure composite material, relating to the field of nanomaterial technology, assembling 15nm Fe3O4 particles onto the surface of Au@SiO2 core-shell materials, using hexadecyltrimethylammonium bromide as a template agent, orthosilicon Au@SiO2@Fe3O4 is coated with SiO2 on the surface of Au@SiO2@Fe3O4, and Na2CO3 is used to selectively etch the material to remove CTAB to obtain Au@Fe3O4@m-SiO2 egg yolk-eggshell structure composite material. The invention has the advantages that the thickness of the prepared composite material mesoporous SiO2 shell layer is controllable, has good magnetic separation effect, is beneficial to recovery and recycling, and can be applied in fields such as catalysis.

Description

technical field [0001] The invention relates to the technical field of nanomaterials, in particular to Au@Fe 3 o 4 @m-SiO 2 The preparation method of egg yolk-eggshell structure catalyst. Background technique [0002] Small-sized noble metal nanoparticles have a larger specific surface area and thus have a relatively higher catalytic activity. However, the relatively high surface energy of small-sized noble metal nanoparticles leads to agglomeration and deformation, thus losing catalytic activity and selectivity. [0003] Combining noble metal nanocatalysts with mesoporous SiO 2 Composite formation of egg yolk-eggshell structure is a common method to effectively solve the aggregation of noble metal nanocatalysts, but compared with bare noble metal nanocatalysts, the introduction of the shell will delay the contact between the reaction reagent and the catalyst, resulting in a decrease in catalytic efficiency; the introduction of superparamagnetic Fe 3 o 4 Microspheres a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/89B01J35/00B82Y30/00B82Y40/00
CPCB01J23/002B01J23/8906B01J35/0086B82Y30/00B82Y40/00
Inventor 韩杰金晨静郭荣
Owner YANGZHOU UNIV
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