Method for preparing spongy graphene

A graphene and sponge-like technology, which is applied in the field of preparation of sponge-like graphene with a specific shape, can solve the problems of "ignition", unrealistic, microwave energy dissipation, etc., and achieve uniform product performance, simple, fast and controllable process strong effect

Active Publication Date: 2013-07-17
无锡烯创科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, as mentioned earlier, in order to prevent interference with communication, remote sensing, military use, etc., the microwave frequency band that can be used for heating and processing materials is very limited according to regulations
In addition, microwave irradiation under high vacuum can easily lead to "sparking" and other phenomena, resulting in the dissipation of microwave energy and damage to microwave sources such as magnetrons.
Therefore, in this patent, microwave irradiation with a vacuum lower limit of 0.1Pa in the full-band microwave range of 300MHz to 300GHz is not only unrealistic, but also has certain risks.
In addition, regardless of the authenticity and feasibility of the patent, if the microwave radiation with a lower power limit of 50W is carried out according to the patent, based on the limitation of energy quantization absorption required for the reaction, its energy density cannot exceed the limit of the chemical reaction in principle. A potential barrier is required, and as a result, it is impossible to realize the microwave exfoliation reduction of graphene

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Spongy graphene oxide was prepared as a precursor by freeze-drying method. On the basis of graphite oxide prepared by the Hummers method, 1.5 g of graphite oxide was dissolved in 150 ml of deionized water, placed in a 40° C. water bath and magnetically stirred for 20 minutes to obtain a uniformly dispersed graphite oxide aqueous solution. Using a freeze dryer, first lower the temperature of the freezing chamber to -50°C, then put in the graphite oxide aqueous solution, and freeze it for about 1 hour. After it is completely solidified, turn on the vacuum pump to keep the vacuum below 100Pa, and the temperature of the freezing chamber is about -10~ 0°C, keep this state for about 24 hours, let the water sublime completely to get the spongy graphene oxide precursor. Using the nitrogen adsorption continuous flow method, the porosity of the spongy graphene oxide precursor was determined to be 40%.

[0021] Put 1g of spongy graphene oxide into alumina (Al 2 o 3 ) in the cru...

Embodiment 2

[0024] The preparation process of the spongy graphene oxide precursor is the same as in Example 1, and the spongy precursor is obtained by adjusting the concentration of the graphite oxide aqueous solution, and its porosity is 30%.

[0025] The vacuum microwave irradiation process is the same as that in Example 1. The microwave power and irradiation time are adjusted to 0.5kW and 200 seconds respectively, the vacuum degree of the resonant cavity is controlled below 50KPa, and then microwave irradiation is performed on the sample. After the treatment, a black spongy product was obtained in the crucible. The porosity of the product was determined to be 33% by nitrogen adsorption continuous flow method, and X-ray diffraction (XRD) and high-resolution transmission electron microscopy were used to prove that the product was graphene, and the number of stacked carbon ring sheets was mainly between 3 and 8 layers.

Embodiment 3

[0027] The preparation process of the spongy graphene oxide precursor is the same as in Example 1, and the spongy precursor is obtained by adjusting the concentration of the graphite oxide aqueous solution, and its porosity is 60%.

[0028] The vacuum microwave irradiation process is the same as that in Example 1, the microwave power and irradiation time are adjusted to 8kW and 30 seconds respectively, the vacuum degree of the resonant cavity is controlled below 30KPa, and then microwave irradiation is performed on the sample. After the treatment, a black spongy product was obtained in the crucible. Using the nitrogen adsorption continuous flow method, the porosity of the product was determined to be 65%. X-ray diffraction (XRD) and high-resolution transmission electron microscopy were used to prove that the product was graphene, and the number of stacked carbon ring sheets was basically between 4 and 7 layers. , and there are more single-layer or double-layer graphene structu...

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Abstract

The invention relates to a method for preparing spongy graphene. The method comprises the steps: with graphite oxide as a raw material, preparing spongy oxidized graphene by lyophilization, wherein the prepared spongy oxidized graphene is used as a precursor; putting the prepared precursor into a crucible; then putting the crucible into a micro-wave vacuum sintering furnace, and irradiating by microwaves after vacuumizing, so as to obtain the spongy graphene. The prepared spongy graphene has a loose and porous unique structure, so that the spongy graphene has wide application prospect in the fields such as a super capacitor, a hydrogen storage material, a sensor and an adsorbing material. According to the method, microwave energy is instantaneously converted into internal energy of a sample based on a high-energy microwave irradiation mode; and by drastic thermal motion of molecules, oxygen-containing groups on the oxidized graphene are reduced into gas which rapidly volatiles and escape. Thus, the graphene can be obtained in a reducing manner and the loose and porous spongy aggregation structure can be remained.

Description

technical field [0001] The invention belongs to the technical category of graphene preparation and belongs to a method for preparing graphene with a sponge-like specific shape. Background technique [0002] Graphene refers to a two-dimensional atomic crystal material composed of closely arranged carbon atoms with less than 10 layers. Due to its unique structure and excellent electrical, thermal, and mechanical properties, graphene has broad application prospects in nanoelectronic devices, composite materials, solar cells, supercapacitors, and hydrogen storage materials. Compared with film-like and powder-like graphene, sponge-like graphene has larger specific surface area and surface properties, looser pore structure and surface structure, and has greater applications in supercapacitors, adsorption, catalyst carriers, etc. value. However, there is no very effective method for rapid synthesis of sponge-like graphene. The preparation of sponge-like graphene by microwave tec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04C01B32/184
Inventor 王继刚丁滔薛伟江
Owner 无锡烯创科技有限公司
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