WO2018188419A1

WO2018188419A1 - Preparation method for use with graphene-based porous carbon network

Info

Publication number: WO2018188419A1
Application number: PCT/CN2018/077170
Authority: WO
Inventors: 高超; 陈琛; 韩燚
Original assignee: 杭州高烯科技有限公司
Priority date: 2017-04-14
Filing date: 2018-02-26
Publication date: 2018-10-18
Also published as: CN106986647B; CN106986647A

Abstract

A preparation method for use with a graphene-based porous carbon network. The method comprises: firstly, preparing and obtaining graphene oxide microspheres by means of a spray drying method by using a single-layer graphene oxide dispersion liquid; then uniformly mixing the graphene oxide microspheres with a biomass carbon source and an activator; processing at a high temperature within a limited space, and then obtaining a porous carbon network. The graphene-based porous carbon network has abundant pore structures, has a large specific surface area and pore volume, and is low density; the present invention may be used in the fields of air purification, water treatment, wave-absorbtion materials, electrochemical materials and the like.

Description

Preparation method of graphene-based porous carbon network

Technical field

The invention belongs to the field of graphene materials and relates to a preparation method of a graphene-based porous carbon network.

Background technique

With the continuous development of industrial society, air pollution has become one of the important threats to human life. For example, formaldehyde, which is emitted from indoor coatings and furniture after decoration, has high carcinogenicity and PM2.5, which has received extensive attention in recent years. People's respiratory and lung functions cause irreversible effects. Therefore, research on high-efficiency adsorption materials is a hot spot. Activated carbon is a material with high carbon content and relatively developed voids, such as coal, nutshell, wood, bone, petroleum residue, etc., which is first carbonized and then subjected to high temperature activation treatment at 800 to 1500 degrees to form a developed micro. The pores and mesopores make their specific surface area and adsorption capacity meet certain requirements. The production of ordinary activated carbon is generally divided into two processes, first: carbonization, and second: activation. Activated carbon is divided into hundreds of kinds of decolorizing activated carbon, water-purifying activated carbon, air-purifying activated carbon, heavy metal recycling activated carbon, etc. It is widely used and is the most effective adsorbing material that can be achieved at the current scientific level.

As a new type of two-dimensional carbon material, graphene has attracted more and more attention from the world. Due to its superior mechanical properties, electrical properties, thermal properties and unique electromagnetic properties, graphene has shown broad application prospects in many fields and has gradually moved to practical applications. In particular, the ultra-high specific surface area of graphene (2600 m ² /g) has great application potential in the field of adsorbent materials. However, at present, graphene materials are faced with problems such as low strength and difficulty in maintaining pore structure. Therefore, combining graphene with other materials can achieve an effect of one plus one greater than one. Patent 201310590113.7 "Preparation method of graphene modified activated carbon" adopts simple mixing to match graphene with traditional wood or straw activated carbon, and obtains graphene-modified activated carbon after activation, which has high specific surface area and can be used in capacitor field. . However, it is more promising to simply mix and match the high specific surface area of graphene itself and explore new composite methods.

Summary of the invention

The object of the present invention is to provide a method for preparing a porous carbon network based on graphene in view of the deficiencies of the prior art.

The object of the present invention is achieved by the following technical solutions: a method for preparing a graphene-based porous carbon network, comprising the following steps:

(1) drying a single layer of graphene oxide dispersion by an atomization drying method to obtain graphene oxide microspheres;

(2) mixing the graphene oxide microspheres obtained in the step (1) with a biomass carbon source and an activator at a mass ratio of 100:10 to 200:100 to 300, grinding to 300 to 400 mesh, and transferring to a mold. , the filling rate is 90 to 100%;

(3) After the mold is sealed, the mixture is carbonized, activated, and washed to obtain a porous carbon network.

Further, the atomization drying temperature described in the step (1) is 100 to 200 °C.

Further, potassium hydroxide is further added to the graphene oxide dispersion described in the step (1), and the mass ratio of potassium hydroxide to graphene oxide is 0.1 to 1:1.

Further, the biomass carbon source described in the step (2) is one or more of straw, coconut shell, sucrose residue, wood chips, walnut shell, apricot shell, and hay, and the activator is potassium hydroxide or sodium hydroxide. One kind.

Further, the carbonization temperature in the step (3) is 300 to 500 ° C, the carbonization time is 1 to 6 hours, the activation temperature is 500 to 1000 ° C, and the activation time is 1 to 4 hours.

The invention has the beneficial effects that the present invention firstly prepares the graphene oxide microspheres by the atomization drying method, and then mixes with the biomass carbon source and the activator uniformly, and performs high temperature treatment together to obtain a porous carbon network. The surface of the graphene oxide has a rich oxygen-containing functional group, and the group is rapidly removed under the heated condition to generate a gas, so that the graphene layer stack structure is opened to obtain a microporous structure. The graphene oxide microspheres obtained by atomization drying rapidly expand like popcorn during heat treatment to produce a rich pore structure, and at the same time, the gas released by the biomass carbon source during carbonization can further expand the graphene sphere. The activated carbon between the expanded graphene sphere and the sphere is squeezed such that a uniform layer of activated carbon is formed between the sphere and the sphere to form a carbon network. The activator (potassium hydroxide) reacts with both activated carbon and graphene to create new pores. The porous material obtained by the invention has high specific surface area, high porosity and low density, and has good stability, and can be used in the fields of air purification, water treatment, catalytic carrier, electrochemical material and the like.

detailed description

A method of preparing a graphene-based porous carbon network includes the following steps:

(1) drying the single-layer graphene oxide dispersion by an atomization drying method to obtain graphene oxide microspheres; the atomization drying temperature is 100 to 200 ° C; and the potassium oxide oxide dispersion is further added with potassium hydroxide. The mass ratio of potassium hydroxide to graphene oxide is 0.1 to 1:1; (2) the graphene oxide microspheres obtained in the step (1) are mixed with the biomass carbon source and the activator, and the mass ratio is 100:10~ 200: 100 ~ 300, grinding to 300 ~ 400 mesh, transferred to the mold, the filling rate is 90 ~ 100%; the biomass carbon source is straw, coconut shell, sucrose residue, wood chips, walnut shell, apricot shell, One or more kinds of dry grass, the activator is one of potassium hydroxide and sodium hydroxide; (3) after sealing the mold, carbonizing, activating and washing the mixture to obtain a porous carbon network; the carbonization temperature The temperature is from 300 to 500 ° C, the carbonization time is from 1 to 6 hours, the activation temperature is from 500 to 1000 ° C, and the activation time is from 1 to 4 hours.

The present invention will be specifically described by the following examples, which are only used to further illustrate the present invention, and are not to be construed as limiting the scope of the present invention. Those skilled in the art will make some non-essential changes according to the contents of the above invention. And adjustments are within the scope of protection of the present invention.

The microspheres described in the present invention are common technical terms in the art and are not intended to define the diameter. The diameter of the microspheres is not the object of the present invention. In addition, the diameter of the microspheres prepared by the method of the present invention varies from 100 nm to 50 um.

Example 1:

(1) drying a mixed dispersion of a single layer of graphene oxide and potassium hydroxide by an atomization drying method, wherein a mass ratio of potassium hydroxide to graphene oxide is 0.1:1, obtaining graphene oxide microspheres, and atomizing The temperature is 130 ° C;

(2) The graphene oxide microspheres obtained in the step (1) are mixed with a coconut shell and potassium hydroxide at a mass ratio of 100:10:100, ground to 300-400 mesh, and transferred to a mold at a filling ratio of 90. %;

(3) After the mold was sealed, the mixture was carbonized at 500 ° C for 2 h, activated at 800 ° C for 2 h, and washed to obtain a porous carbon network.

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.17 g/cm ³ , the specific surface area was 1840 m ² /g, and the pore volume was 1.75 cm ³ /g.

Example 2:

(1) drying a mixed dispersion of a single layer of graphene oxide and potassium hydroxide by an atomization drying method, wherein a mass ratio of potassium hydroxide to graphene oxide is 1:1, obtaining graphene oxide microspheres, and atomizing The temperature is 130 ° C;

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.14 g/cm ³ , the specific surface area was 2030 m ² /g, and the pore volume was 2.28 cm ³ /g.

Example 3:

(1) drying a single layer of graphene oxide dispersion by atomization drying method to obtain graphene oxide microspheres, the atomization temperature is 130 ° C;

(2) The graphene oxide microspheres obtained in the step (1) are mixed with a coconut shell and potassium hydroxide at a mass ratio of 100:120:200, ground to 300-400 mesh, and transferred to a mold at a filling ratio of 90. %;

(3) After sealing the mold, the mixture was carbonized at 300 ° C for 6 h, activated at 800 ° C for 2 h, and washed to obtain a porous carbon network.

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.37 g/cm ³ , the specific surface area was 1510 m ² /g, and the pore volume was 1.24 cm ³ /g.

Example 4:

(2) The graphene oxide microspheres obtained in the step (1) are mixed with a coconut shell and potassium hydroxide at a mass ratio of 100:200:300, ground to 300-400 mesh, and transferred to a mold at a filling ratio of 90. %;

(3) After sealing the mold, the mixture was carbonized at 500 ° C for 1 h, activated at 500 ° C for 4 h, and washed to obtain a porous carbon network.

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.46 g/cm ³ , the specific surface area was 1270 m ² /g, and the pore volume was 0.94 cm ³ /g.

Example 5:

(1) drying a single layer of graphene oxide dispersion by atomization drying method to obtain graphene oxide microspheres, the atomization temperature is 200 ° C;

(2) The graphene oxide microspheres obtained in the step (1) are mixed with straw and potassium hydroxide at a mass ratio of 100:60:150, ground to 300-400 mesh, transferred to a mold, and the filling ratio is 100%. ;

(3) After the mold was sealed, the mixture was carbonized at 500 ° C for 2 h, activated at 1000 ° C for 1 h, and washed to obtain a porous carbon network.

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.22 g/cm ³ , the specific surface area was 1360 m ² /g, and the pore volume was 0.97 cm ³ /g.

Example 6

(1) drying a single layer of graphene oxide dispersion by atomization drying method to obtain graphene oxide microspheres, the atomization temperature is 100 ° C;

(2) The graphene oxide microspheres obtained in the step (1) are mixed with wood chips and potassium hydroxide at a mass ratio of 100:60:150, ground to 300-400 mesh, and transferred to a mold at a filling rate of 95%. ;

(3) After the mold was sealed, the mixture was carbonized at 300 ° C for 2 h, activated at 1000 ° C for 2 h, and washed to obtain a porous carbon network.

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.19 g/cm ³ , the specific surface area was 1480 m ² /g, and the pore volume was 1.02 cm ³ /g.

Example 7

(1) drying a single-layer graphene oxide dispersion by an atomization drying method, and drying a mixed dispersion of a single layer of graphene oxide and potassium hydroxide, wherein the mass ratio of potassium hydroxide to graphene oxide is 1:1. , obtaining graphene oxide microspheres, the atomization temperature is 100 ° C;

(2) The graphene oxide microspheres obtained in the step (1) are mixed with a coconut shell and potassium hydroxide at a mass ratio of 100:60:110, ground to 300-400 mesh, and transferred to a mold at a filling ratio of 95. %;

(3) After sealing the mold, the mixture was carbonized at 300 ° C for 2 h, activated at 1000 ° C for 2 h, and washed to obtain a porous carbon network.

Through the above steps, a graphene-based porous carbon network is obtained, which is a black fluffy block. The density was 0.16 g/cm ³ , the specific surface area was 1870 m ² /g, and the pore volume was 2.17 cm ³ /g.

Claims

A method for preparing a graphene-based porous carbon network, comprising the steps of:

(1) drying a single layer of graphene oxide dispersion by an atomization drying method to obtain graphene oxide microspheres;

(2) mixing the graphene oxide microspheres obtained in the step (1) with a biomass carbon source and an activator at a mass ratio of 100:10 to 200:100 to 300, grinding to 300 to 400 mesh, and transferring to a mold. , the filling rate is 90 to 100%;

(3) After the mold is sealed, the mixture is carbonized, activated, and washed to obtain a porous carbon network.
The method according to claim 1, wherein the atomization drying temperature in the step (1) is from 100 to 200 °C.
The method according to claim 1, wherein potassium oxide is further added to the graphene oxide dispersion in the step (1), and the mass ratio of potassium hydroxide to graphene oxide is from 0.1 to 1:1.
The method according to claim 1, wherein the biomass carbon source in the step (2) is one or more of straw, coconut shell, sucrose residue, wood chips, walnut shell, apricot shell, and hay. The activator is one of potassium hydroxide and sodium hydroxide.
The method according to claim 1, wherein the carbonization temperature in the step (3) is 300 to 500 ° C, the carbonization time is 1 to 6 hours, the activation temperature is 500 to 1000 ° C, and the activation time is 1 to 4 hours. .