CN105217622A - A kind of preparation method of controlled three-dimensional grapheme microballoon - Google Patents

Abstract

The invention discloses a method for preparing controllable three-dimensional graphene microspheres, which uses graphene oxide and a support medium as raw materials, adds an appropriate amount of solvent to prepare a slurry, and obtains a graphene oxide/support composite by spray drying, and then The graphene oxide is reduced to obtain a graphene/support composite, and the controllable three-dimensional graphene microspheres are obtained by dissolving the support. The invention has short synthesis cycle, cheap raw materials, simple process and easy control, and has remarkable practical value and good application prospect.

Description

A preparation method of controllable three-dimensional graphene microspheres

technical field

The invention relates to a preparation method of controllable three-dimensional graphene microspheres, belonging to the field of graphene materials and technologies.

Background technique

Graphene is a new material with a single-layer sheet structure composed of carbon atoms. It has ultra-high electron mobility (15000cm ² /V·s), low resistivity (10 ^-6 Ω·cm ), high specific surface area (2630m ² /g), high thermal conductivity (5300W/m·K), high mechanical strength, and are widely used in biology, chemistry, physics, materials and other fields. Obtaining graphene by reducing graphene oxide is a commonly used method, and high-temperature reduction is a method that can produce graphene on a large scale.

Due to the large flake structure of graphene, it is difficult to prepare microsphere structures with controllable size and pore size. In the present invention, controllable spherical graphene is obtained by adding support media, spray drying and high temperature reduction. The obtained controllable graphene microspheres can be used in various aspects such as energy storage, adsorption, and wastewater treatment, and have great potential application prospects.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing controllable three-dimensional graphene microspheres.

Technical scheme of the present invention is:

Use graphene oxide and support medium as raw materials, add an appropriate amount of solvent to prepare a slurry, obtain a graphene oxide/support medium composite by spray drying, and then reduce graphene oxide to obtain a graphene/support medium composite. medium to obtain three-dimensional graphene microspheres with controllable size and pore diameter.

The method of the invention has short flow, easy control, and low cost, achieves directional, high-efficiency, and simple process to prepare controllable three-dimensional graphene microspheres, and is easy to realize large-scale production of controllable three-dimensional graphene microspheres.

The key points of the technical solution of the present invention are: spray drying the graphene oxide and the supporting medium, reducing the graphene oxide and removing the supporting medium to obtain three-dimensional graphene microspheres with controllable size and pore diameter. The method has the advantages of simple operation, short preparation time, no pollution, low cost and high yield.

The technical solution of the present invention may specifically include the following steps:

(1) ultrasonically disperse graphene oxide in a solvent to obtain a graphene oxide dispersion;

(2) Adding a support medium to the graphene oxide dispersion, stirring to disperse, and spray-drying the dispersion to obtain a graphene oxide/support medium composite;

(3) The graphene oxide/support medium composite is reduced to graphene oxide to obtain a graphene/support medium composite;

(4) The obtained graphene/support medium composite is dissolved to obtain three-dimensional porous graphene oxide microspheres by dissolving the support medium.

Further, the solvent used in step (1) is water, ethanol, propanol, DMF, NMP and other solvents to obtain a dispersion with a concentration of 0.5-5 mg/mL;

Further, the supporting media used are simple substances (silicon powder, iron powder, copper powder, zinc powder, carbon powder, etc.), oxides (such as silicon oxide, silicon oxide, iron oxide, copper oxide, aluminum oxide, cobalt oxide, oxide Nickel, etc.), salt (phosphate, sulfate, carbonate, nitrate, sodium chloride, sodium bromide, sodium iodide, etc.), polymer (polystyrene, etc.);

Further, the mass fraction of the supporting medium used is 5% to 60%;

Further, the temperature used for spray drying is 80~300°C

Further, the reduction can be carried out at high temperature, the high temperature reduction temperature is 200-1000°C, and the use atmosphere is air, argon, nitrogen or hydrogen; or it can be reduced with hydrazine hydrate, hydrogen iodide, etc.

Further, the dissolution method used is to choose acid dissolution, alkali dissolution or other solvent dissolution according to the characteristics of the support medium.

Based on the principle of the above invention, the method sprays and dries the graphene oxide and the support medium, and after reducing the graphene oxide, removes the support medium to obtain three-dimensional graphene with controllable size and pore diameter. The present invention has the following advantages and beneficial effects:

1. Selected graphene oxide and support medium, low raw material cost;

2. By adjusting the ratio of graphene oxide and support medium, graphene microspheres with different diameters and pore sizes can be obtained;

3. Containing the graphene microspheres of the present invention, the price is cheap, the synthesis process is simple, easy to control, and can be applied to applications in chemistry, physics, biology, medical treatment, etc.;

4. The invention has short synthesis period, cheap raw materials, simple process and easy control, and has remarkable practical value and good application prospect.

Description of drawings

Fig. 1 is a scanning electron microscope picture of graphene microspheres of the present invention.

Fig. 2 is a transmission electron microscope picture of graphene microspheres of the present invention.

Fig. 3 is a scanning electron microscope picture of graphene and titanium dioxide composite microspheres of the present invention, and a transmission electron microscope picture of graphene obtained after dissolving titanium dioxide.

detailed description

Example 1

70 ml of a 2 mg/ml graphene oxide aqueous solution was prepared, 10 g of nano-silicon oxide was added thereto, and stirred for one hour to obtain a slurry. The slurry was spray-dried at an inlet temperature of 250° C. and an outlet temperature of 100° C., and spray-dried to obtain a composite of graphene oxide and silicon oxide.

The compound was heated to 600° C. under argon gas and kept for four hours to obtain a compound of graphene and silicon oxide. The silicon oxide is dissolved by a certain concentration of HF solution to obtain porous graphene microspheres. Figure 1 shows the scanning electron microscope image of the obtained graphene microspheres.

Example 2

100 ml of a 5 mg/ml graphene oxide aqueous solution was prepared, 15 g of sodium chloride was added thereto, stirred and dissolved, and a solution was obtained. The solution was spray-dried at an inlet temperature of 290° C. and an outlet temperature of 120° C., and spray-dried to obtain a composite of graphene oxide and sodium chloride.

The composite was heated to 500° C. in an Ar/H ₂ (H ₂ content: 10%) atmosphere, and kept at a constant temperature for 5 hours to obtain a composite of graphene and sodium chloride. By adding the composite into water, heating and stirring to dissolve sodium chloride, porous graphene microspheres are obtained. Figure 2 shows a transmission electron microscope image of the obtained graphene microspheres.

Example 3

Prepare 100 ml of a 1 mg/ml graphene oxide aqueous solution, add 20 g of nano-titanium dioxide (P25) into it, and stir to obtain a dispersion. The dispersion liquid was spray-dried at an inlet temperature of 250° C. and an outlet temperature of 110° C., and spray-dried to obtain a composite of graphene oxide and titanium dioxide.

The composite was heated up to 400° C. in a nitrogen atmosphere and kept at a constant temperature for 6 hours to obtain a composite of graphene and titanium dioxide. By adding the complex into HF, heating and stirring to dissolve titanium dioxide, obtain porous graphene microspheres.

Example 4

Prepare 60 ml of 2 mg/ml graphene oxide ethanol solution, add 20 g of polystyrene balls therein, and stir to obtain a dispersion. The dispersion liquid was spray-dried at an inlet temperature of 200° C. and an outlet temperature of 100° C., and spray-dried to obtain a composite of graphene oxide and polystyrene.

The composite was dispersed in a hydrazine hydrate solution, kept at 80° C. for 3 hours, and centrifuged to obtain a composite of graphene and polystyrene. Add the complex into chloroform, heat and stir to dissolve the polystyrene, and obtain porous graphene microspheres.

Claims (7)

1. a preparation method for controlled three-dimensional grapheme microballoon, is characterized in that,

With graphene oxide, Supporting Media for raw material, add appropriate solvent and be modulated into slurry, graphene oxide/Supporting Media mixture is obtained by spraying dry, then redox graphene, obtain Graphene/Supporting Media mixture, by dissolving Supporting Media, obtain the three-dimensional grapheme microballoon that size, aperture are controlled.

2. preparation method according to claim 1, is characterized in that, specifically comprises following steps:

(1) make graphene oxide ultrasonic disperse in a solvent, obtain the dispersion liquid of graphene oxide;

(2) in the dispersion liquid of graphene oxide, add Supporting Media, dispersed with stirring, dispersion liquid is carried out spraying dry, obtain graphene oxide/Supporting Media mixture;

(3) graphene oxide/Supporting Media mixture reduces, and obtains Graphene/Supporting Media mixture;

(4) Graphene/Supporting Media mixture will obtained, by dissolving Supporting Media, obtains three-dimensional porous graphene oxide microballoon.

3. preparation method according to claim 2, is characterized in that, the solvent that step (1) uses is water, ethanol, propyl alcohol, DMF or NMP, obtains the dispersion liquid that concentration is 0.5 ~ 5mg/mL.

4. preparation method according to claim 2, is characterized in that, Supporting Media is one or more in simple substance, oxide compound, salt.

5. preparation method according to claim 2, is characterized in that, the massfraction of the Supporting Media of use is 5% ~ 60%.

6. preparation method according to claim 2, is characterized in that, the temperature that spraying dry uses is 80 ~ 300 DEG C.

7. preparation method according to claim 2, is characterized in that, in step (3), reduction uses high temperature reduction, and high temperature reduction temperature is 200 ~ 1000 DEG C, uses atmosphere to be air, argon gas, nitrogen or hydrogen; Or with hydrazine hydrate or hydrogen iodide reduction.