CN112357912A - Method for preparing graphene through electrochemical anode stripping - Google Patents
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Abstract
The invention relates to a method for preparing graphene by electrochemical anode stripping, which comprises the following steps: mixing a sulfuric acid solution and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt to serve as an electrolyte, or mixing sodium hydroxide, hydrogen peroxide and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt to serve as an electrolyte; taking a graphite rod/graphite foil to be stripped as an anode and the other graphite rod as a cathode, and switching on a power supply under the condition of oil bath and electrolyte stirring; pre-stripping the graphite rod/graphite foil to be stripped, then boosting the pressure to carry out formal stripping, and completely stripping the graphite rod/graphite foil to be stripped until the current is 0; and carrying out ultrasonic treatment on the obtained product to obtain the graphene aqueous solution. The oxidation degree and the defect degree of the graphene can be controlled, and the graphene can be kept for a long time without precipitation.
Description
Technical Field
The invention relates to the field of graphene, in particular to a method for preparing graphene by electrochemical anode stripping.
Background
Graphene is a defect-free flat carbon monolayer with a theoretical surface area of 2630m2g-1And is the basic unit of the two-dimensional carbon family. The carrier mobility of graphene at room temperature can reach 15000cm2V-1s-1And charge carriers can be modulated between electrons and holes. Accordingly, the conductivity of graphene is high, such asThe conductivity of the electrochemical energy storage of the graphene-based composite material is improved. The mechanical properties of graphene are very good because it has strong C-C bonds, high young's modulus and breaking strength, which is almost 200 times that of steel.
The excellent mechanical properties of graphene make the graphene an ideal basic material for flexible and wearable electrochemical energy storage devices, but it should be noted that the mechanical properties of graphene may be significantly affected by the presence of defects in the graphene, and the mechanical properties of the graphene may be reduced as the number of defects increases.
There is a technical barrier to the current methods for preparing graphene, and so far, chemical vapor deposition is still the main method for industrially stripping graphite and reducing graphene oxide to prepare small graphene sheets, but the method has high cost, relatively low yield and general product quality. The reduction of graphene oxide is one of the methods for preparing graphene on a large scale at present, the method has high product yield and can effectively control the cost, but the product quality is mainly at a middle and lower level due to the existence of unavoidable internal deformation and external defects, and the performance of the graphene is influenced. Electrochemical exfoliation is considered a promising strategy for large-scale production of high-quality graphene at lower cost, and typically introduces an electrical current to facilitate structural changes of the graphite working electrode in the liquid electrolyte. The graphene prepared by electrochemical stripping has the advantages of low cost, short reaction period and strong controllability, and the thickness of the graphene and the oxidation degree and defect degree of the graphene can be effectively changed by controlling different electrolyte types, electrolyte concentrations, voltage, current and other factors.
Although the electrochemical stripping method is convenient and quick, and is green and environment-friendly, most of the existing documents only extract the supernatant of the stripped graphite, most of the stripped graphite precipitate is discarded, the yield of the graphene is greatly reduced, in addition, the electrochemical stripping is mostly carried out in aqueous solution, the graphene is extremely easy to agglomerate, and the graphene prepared by the methods is difficult to store for a long time.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a method for preparing graphene by electrochemical anode stripping, so as to overcome the defects in the prior art.
The technical scheme for solving the technical problems is as follows: a method for preparing graphene by electrochemical anode stripping comprises the following steps:
s100, mixing a sulfuric acid solution and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt to serve as an electrolyte, or mixing sodium hydroxide, hydrogen peroxide and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt to serve as an electrolyte;
s200, taking the graphite rod/graphite foil to be stripped as an anode and the other graphite rod as a cathode, and switching on a power supply under the condition of oil bath and electrolyte stirring;
s300, pre-stripping the graphite rod/graphite foil to be stripped, then boosting the pressure to carry out formal stripping, and completely stripping the graphite rod/graphite foil to be stripped until the current is 0;
s400, performing ultrasonic treatment on the product obtained in the step S300 to obtain a graphene aqueous solution.
Further: in the S100, the concentration of a sulfuric acid solution is 0.5-1.5M, the addition amount of the sulfuric acid solution is 100ml, and the addition amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt is 0.5-5 g;
or the concentration of the sodium hydroxide is 0.5-2M, the addition amount of the sodium hydroxide solution is 100ml, the addition amount of 30% volume fraction hydrogen peroxide is 2-10 ml, and the addition amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt is 0.5-5 g.
Further: the concentration of the sulfuric acid solution was 1.0M, and the amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt added was 0.7 g;
or the concentration of the sodium hydroxide solution is 1.5M, and the addition amount of 30% hydrogen peroxide is 5 ml; the amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt added was 0.7 g.
Further: in the S200, the oil bath temperature is 25-95 ℃.
Further: the oil bath temperature was 70 ℃.
Further: in the S300, the pre-stripping voltage is 1V-5V; the formal peeling voltage is 8V to 20V.
Further: the pre-stripping time is 0-3 min.
Further: the pre-stripping voltage is 2V; the formal peeling voltage was 10V.
Further: in the step S400, the ultrasonic time is 1-8 h.
The invention has the beneficial effects that:
the design idea of the invention is that the oxidation degree of the graphene product is regulated and controlled by changing the electrolyte for stripping graphite, the graphene product is stably stored in an aqueous solution for a long time, and the graphite is stripped by adopting a sulfuric acid solution with a good stripping effect, but because the oxidizing property of sulfuric acid and hydrogen peroxide is strong, 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt with low price is added into the solution as an additive, and the additive can be used as an intercalator to assist SO4 2-Ion or 02 2-The ion-stripping graphite regulates and controls the oxidation degree and defect degree of the prepared graphene, and can also be used as a surfactant, so that the generated graphene stably exists in an aqueous solution and can be stored for a long time;
according to the invention, the oxidation degree and defect degree of graphene can be controlled by regulating the type of the electrolyte and the concentration of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt, the thickness of graphene can be effectively controlled by regulating the ultrasonic time, all products can be converted into graphene by ultrasonic, the graphene is stored in the dispersion liquid containing the 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt, the graphene can be kept for a long time without precipitation, the experimental process is safe and simple, the conditions are controllable, the cost is low, and the subsequent industrial production is facilitated.
Drawings
FIG. 1 is a scanning electron microscope image of graphene prepared by electrochemical exfoliation of sulfuric acid and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt as an electrolyte in example 1.
FIG. 2 is a scanning electron microscope image of graphene prepared by electrochemical exfoliation of sodium hydroxide, hydrogen peroxide and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt as electrolytes in example 2.
FIG. 3 is Raman spectrum test data, wherein G-HSR is graphene prepared by electrochemical exfoliation of sulfuric acid and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt as an electrolyte in example 1; G-NHR is graphene prepared by electrochemical stripping of sodium hydroxide, hydrogen peroxide and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt serving as electrolyte in example 2; c is graphite.
Fig. 4 is a photograph of the prepared graphene aqueous dispersion.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
Example 1
A method for preparing graphene by electrochemical anode stripping comprises the following steps:
s100, preparing 100ml of 1M sulfuric acid solution, adding 0.7g of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt (commonly known as sunset yellow) into the sulfuric acid solution, and uniformly stirring to obtain a solution serving as an electrolyte;
s200, taking the graphite rod/graphite foil to be stripped as an anode and the other graphite rod as a cathode, carrying out oil bath at 70 ℃ and switching on a power supply while keeping the electrolyte stirred;
s300, pre-stripping the graphite rod/graphite foil to be stripped for 2min at 2V, then boosting the pressure to 10V for formal stripping, and enabling the graphite rod/graphite foil to be stripped to be completely stripped until the current is 0;
s400, carrying out ultrasonic treatment on the product obtained in the step S300 for 1-8 h, and dispersing after washing to obtain the graphene aqueous solution.
Example 2
A method for preparing graphene by electrochemical anode stripping comprises the following steps:
s100, preparing 100ml of 1.5M sodium hydroxide solution, adding 5ml of 30 volume percent hydrogen peroxide and 0.5g of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt (commonly known as sunset yellow) into the sodium hydroxide solution, and uniformly stirring to obtain a solution serving as an electrolyte;
s200, taking the graphite rod/graphite foil to be stripped as an anode and the other graphite rod as a cathode, carrying out oil bath at 95 ℃ and switching on a power supply while keeping the electrolyte stirred;
s300, pre-stripping the graphite rod/graphite foil to be stripped for 2min at 1V, then boosting the pressure to 8V for formal stripping, and enabling the graphite rod/graphite foil to be stripped to be completely stripped until the current is 0;
s400, carrying out ultrasonic treatment on the product obtained in the step S300 for 1-8 h, and dispersing after washing to obtain the graphene aqueous solution.
Example 3
A method for preparing graphene by electrochemical anode stripping comprises the following steps:
s100, dissolving 5g of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt (commonly known as sunset yellow) in 100ml of deionized water, and uniformly stirring to obtain a solution serving as an electrolyte;
s200, taking the graphite rod/graphite foil to be stripped as an anode and the other graphite rod as a cathode, carrying out oil bath at 25 ℃ and switching on a power supply while keeping the electrolyte stirred;
s300, pre-stripping the graphite rod/graphite foil to be stripped for 2min at 20V, then boosting the pressure to 10V for formal stripping, and enabling the graphite rod/graphite foil to be stripped to be completely stripped until the current is 0;
s400, carrying out ultrasonic treatment on the product obtained in the step S300 for 1-8 h, and dispersing after washing to obtain the graphene aqueous solution.
The design idea of the invention is that the oxidation degree of the graphene product is regulated and controlled by changing the electrolyte for stripping graphite, the graphene product is stably stored in an aqueous solution for a long time, and the sulfuric acid solution with good stripping effect is used for stripping graphite, but because the oxidizing property of sulfuric acid is strong, 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt with low price is added into the solution as an additive, the additive can be used as an intercalator to assist sulfuric acid to strip graphite, regulate and control the oxidation degree and defect degree of the prepared graphene, and can also be used as a surfactant, so that the generated graphene stably exists in the aqueous solution and can be stored for a long time.
According to the invention, the oxidation degree and defect degree of graphene can be controlled by regulating the concentration of sulfuric acid and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt, the thickness of graphene can be effectively controlled by regulating the ultrasonic time, all products can be converted into graphene by ultrasonic, the graphene is stored in the dispersion liquid containing the 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt, the graphene can be kept for a long time without precipitation, the experimental process is safe and simple, the conditions are controllable, the cost is low, and the subsequent industrial production is facilitated.
The samples in fig. 1 were remarkably wrinkled and highly transparent, indicating that the number of graphene layers prepared in example 1 was small.
The samples in fig. 2 had less wrinkles than the samples of fig. 1 and were less transparent, indicating that example 2 produced a higher number of graphene layers than example 1.
The Raman spectrum of the graphene in FIG. 3 mainly consists of a D peak at about 1350cm-1, a G peak at about 1580cm-1, and a 2D peak at about 2700 cm-1. In FIG. 3, the ID/IG of C is about 0.11, the ID/IG of G-NHR is about 0.19, the ID/IG of G-HSR is about 1.46, and the G peak is broadened, indicating that the defect degree of the graphene prepared by the example 1 and the example 2 is larger than that of the common graphite, while the defect degree and the edge number of the graphene prepared by the example 1 are larger than those of the example 1. By combining fig. 1 and fig. 2, the invention is illustrated that graphene with different defect degrees and thicknesses can be effectively prepared.
Fig. 4 shows that the graphene dispersion prepared according to the present invention did not generate significant precipitates and did not delaminate during the standing for 2 months, indicating good stability.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (9)
1. A method for preparing graphene by electrochemical anode stripping is characterized by comprising the following steps:
s100, mixing a sulfuric acid solution and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt to serve as an electrolyte, or mixing sodium hydroxide, hydrogen peroxide and 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt to serve as an electrolyte;
s200, taking the graphite rod/graphite foil to be stripped as an anode and the other graphite rod as a cathode, and switching on a power supply under the condition of oil bath and electrolyte stirring;
s300, pre-stripping the graphite rod/graphite foil to be stripped, then boosting the pressure to carry out formal stripping, and completely stripping the graphite rod/graphite foil to be stripped until the current is 0;
s400, performing ultrasonic treatment on the product obtained in the step S300 to obtain a graphene aqueous solution.
2. The method for preparing graphene through electrochemical anodic stripping according to claim 1, wherein in S100, the concentration of a sulfuric acid solution is 0.5-1.5M, the addition amount of the sulfuric acid solution is 100ml, and the addition amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt is 0.5-5 g;
or the concentration of the sodium hydroxide is 0.5-2M, the addition amount of the sodium hydroxide solution is 100ml, the addition amount of 30% volume fraction hydrogen peroxide is 2-10 ml, and the addition amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt is 0.5-5 g.
3. The method for preparing graphene by electrochemical anodic stripping according to claim 2, wherein the concentration of the sulfuric acid solution is 1.0M, and the addition amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt is 0.7 g;
or the concentration of the sodium hydroxide solution is 1.5M, and the addition amount of 30% hydrogen peroxide is 5 ml; the amount of 1- (4 '-sulfo-1' -phenylazo) -2-naphthol-6-sulfonic acid disodium salt added was 0.7 g.
4. The method for preparing graphene by electrochemical anodic stripping as claimed in claim 1, wherein in the step S200, the oil bath temperature is 25 ℃ to 95 ℃.
5. The method for preparing graphene by electrochemical anodic stripping as claimed in claim 4, wherein the oil bath temperature is 70 ℃.
6. The method for preparing graphene by electrochemical anodic stripping according to claim 1, wherein in S300, the pre-stripping voltage is 1V to 5V; the formal peeling voltage is 8V to 20V.
7. The method for preparing graphene through electrochemical anodic stripping according to claim 6, wherein the pre-stripping time is 0-3 min.
8. The method for preparing graphene through electrochemical anodic stripping according to claim 6, wherein the pre-stripping voltage is 2V; the formal peeling voltage was 10V.
9. The method for preparing graphene through electrochemical anodic stripping according to claim 1, wherein in the step S400, the ultrasonic time is 1-8 h.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113501516A (en) * | 2021-08-26 | 2021-10-15 | 枣庄市三兴高新材料有限公司 | Preparation method of high-purity coal-series graphite |
| CN114497493A (en) * | 2022-01-21 | 2022-05-13 | 华中科技大学 | Electrically-stripped graphene silicon carbon composite material and preparation method and application thereof |
| CN115182021A (en) * | 2021-04-01 | 2022-10-14 | 浙江正泰电器股份有限公司 | Composite dispersant and mixed electroplating solution |
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| CN111204749A (en) * | 2020-01-17 | 2020-05-29 | 桂林电子科技大学 | Method for electrochemically preparing low-oxygen-content graphene |
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Patent Citations (4)
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| CN102583356A (en) * | 2012-03-20 | 2012-07-18 | 无锡第六元素高科技发展有限公司 | Method for transferring and washing graphene film |
| CN107954420A (en) * | 2017-11-13 | 2018-04-24 | 广西师范大学 | A kind of Anodic peels off the method that graphite prepares three-dimensional grapheme |
| CN108821268A (en) * | 2018-06-20 | 2018-11-16 | 青岛烯碳瑞尔新材料科技有限公司 | A kind of green high-efficient electrochemical preparation method of high quality water-soluble graphene |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115182021A (en) * | 2021-04-01 | 2022-10-14 | 浙江正泰电器股份有限公司 | Composite dispersant and mixed electroplating solution |
| CN113501516A (en) * | 2021-08-26 | 2021-10-15 | 枣庄市三兴高新材料有限公司 | Preparation method of high-purity coal-series graphite |
| CN114497493A (en) * | 2022-01-21 | 2022-05-13 | 华中科技大学 | Electrically-stripped graphene silicon carbon composite material and preparation method and application thereof |
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