Oriented graphene oxide preparation method based on graphene oxide magnetization orientation technology

Abstract

The invention discloses a preparation method of oriented graphene oxide based on a graphene oxide magnetization orientation technology, which belongs to the technical field of graphene preparation and comprises the following steps: selecting high-purity graphite powder as an initial raw material, pretreating, oxidizing the graphite powder pretreated by an improved Hummers method into graphene oxide, and preparing the oriented graphene oxide. Graphene oxide is dispersed in a proper solvent to form a dispersion liquid, the dispersion liquid is placed in an external magnetic field, the magnetic field intensity and direction are adjusted, graphene oxide sheet layers are directionally arranged, the directionally arranged graphene oxide is dried and cured, and the oriented graphene oxide is characterized by FTIR, SEM, XRD and VSM technologies. Preparing parameters are adjusted according to the characterization result; according to the invention, efficient directional arrangement of graphene oxide sheets is successfully realized through a magnetization orientation technology; the directional arrangement not only improves the performance of the graphene oxide in a specific direction, but also provides powerful support for the application of the graphene oxide in the fields of high-performance electronic devices, flexible sensors and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of graphene preparation, and in particular relates to a method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology. Background Art

[0002] Graphene oxide, as a key member of the graphene family, has shown great application potential in many fields such as materials science, electronic devices, energy storage and conversion, water treatment, and biosensing due to its unique two-dimensional structure, rich surface functional groups, and good dispersibility. However, despite the many advantages of graphene oxide, there are still some problems to be solved in its preparation and application, especially in achieving its directional arrangement.

[0003] Problems existing in the prior art:

[0004] 1. Performance optimization of disordered stacking restrictions:

[0005] Graphene oxide prepared by traditional methods often presents a state of disordered stacking. This disorder not only limits its performance optimization in specific directions, such as conductivity, thermal conductivity, mechanical strength, etc., but also affects its dispersion uniformity and interface interaction in the composite material, thereby reducing the overall performance of the composite material.

[0006] 2. The directional arrangement method is complex and costly:

[0007] In order to solve the problem of disordered stacking of graphene oxide, researchers have tried a variety of directional alignment methods, such as chemical deposition, external electric field, mechanical force, etc. However, these methods generally have problems such as complex operation, high cost, and strict equipment requirements, which not only increase the difficulty of preparation, but also limit the large-scale production and wide application of graphene oxide.

[0008] 3. Single characterization method makes it difficult to fully analyze the microstructure:

[0009] In terms of graphene oxide characterization, existing technologies usually rely on a single test method, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. However, these test methods can only provide limited microstructural information, and it is difficult to fully analyze the key characteristics of graphene oxide, such as the degree of oxidation, interplanar spacing, type and distribution of functional groups, morphology and particle size distribution. This makes it difficult to accurately control the microstructure of graphene oxide during the preparation process, thus affecting the optimization and improvement of its performance.

[0010] 4. Environmental pollution and cost issues:

[0011] In the preparation process of graphene oxide, traditional methods often require the use of a large amount of harmful chemicals such as strong acids and strong oxidants, which not only causes serious pollution to the environment, but also increases production costs. At the same time, the residues of these harmful chemicals may also have a negative impact on the performance of graphene oxide, limiting its application in certain fields.

[0012] Therefore, a method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology is needed to solve the above-mentioned problems existing in the prior art. Summary of the invention

[0013] The object of the present invention is to provide a method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology to solve the problems raised in the above background technology.

[0014] To achieve the above object, the present invention provides the following technical solution: a method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology, comprising the following steps:

[0015] S1, select high purity graphite powder as starting material, and carry out pretreatment;

[0016] S2, oxidizing the graphite powder obtained by pretreatment in step S1 into graphene oxide by using an improved Hummers method;

[0017] S3, dispersing the graphene oxide in step S2 in a suitable solvent to form a dispersion;

[0018] S4, placing the dispersion in step S3 in an external magnetic field, adjusting the strength and direction of the magnetic field to align the graphene oxide sheets;

[0019] S5, drying and curing the graphene oxide after the alignment in step S4;

[0020] S6. Characterize the oriented graphene oxide in step S5 using FTIR, SEM, XRD and VSM techniques, and adjust the preparation parameters according to the characterization results.

[0021] It should be noted that the pretreatment in step S1 includes grinding and screening pretreatment to ensure uniform particle size distribution.

[0022] It is further worth noting that the improved Hummers method described in step S2 includes adding graphite powder to a cooled mixture of sulfuric acid and concentrated nitric acid, slowly adding potassium permanganate oxidant, controlling the reaction temperature and time, and obtaining graphene oxide by washing and drying after the reaction is completed.

[0023] It should be further explained that the concentration and dispersion time of the dispersion in step S3 are adjusted according to the characteristics and requirements of the graphene oxide in step S2. The concentration adjustment method of the dispersion can be chemical analysis, physical measurement or direct weighing. After determining the concentration measurement method, according to the characteristics and requirements of graphene oxide (such as conductivity, optical properties, etc.), the target concentration range can be set, and the concentration of the dispersion can be accurately adjusted by adjusting the amount of graphene oxide powder added or the amount of solvent used.

[0024] The dispersion time of the dispersion liquid can be adjusted through a series of experiments to observe the dispersion effect of graphene oxide in the solvent at different dispersion times (such as dispersion uniformity, particle size, etc.), so as to determine the optimal dispersion time. Based on the existing experimental data and empirical formula, the dispersion time required at different concentrations can be estimated. The specific formula is:

[0025] t=k*C n

[0026] Where: t is the required dispersion time;

[0027] k is an empirical constant that depends on factors such as experimental conditions, the properties of graphene oxide, and the type of solvent;

[0028] C is the concentration of the dispersion;

[0029] n is the concentration exponent, which describes the nonlinear relationship between dispersion time and dispersion concentration;

[0030] In order to determine the empirical constant k and the concentration exponent n, a series of experiments are required. In each experiment, different dispersion concentrations are used and the time required to achieve a predetermined dispersion effect is measured. These data can then be used to fit the empirical formula to obtain the values ​​of k and n.

[0031] It should be noted that the values ​​of k and n in the empirical formula may vary due to differences in experimental conditions, properties of graphene oxide, and solvent type. Therefore, when using the empirical formula for estimation, it is necessary to ensure that the experimental conditions match the conditions under which the formula applies.

[0032] As a preferred embodiment, the strength and direction of the external magnetic field in step S4 are precisely controlled according to the magnetic response characteristics and orientation requirements of the graphene oxide in step S2. The magnetic field strength control method can adopt an electromagnet adjustment method and a permanent magnet combination method. After determining the magnetic field strength control method, according to the magnetic response characteristics and orientation requirements (such as magnetic strength, magnetization direction, etc.) of graphene oxide, the target magnetic field strength range can be set, and the magnetic field strength can be precisely controlled by adjusting the current of the electromagnet or the combination of permanent magnets.

[0033] The magnetic field direction control method can adopt the electromagnet direction adjustment method and the permanent magnet rotation method. After determining the magnetic field direction control method, the target magnetic field direction range can be set according to the magnetic response characteristics and directional requirements of graphene oxide (such as directional arrangement direction, magnetization direction, etc.), and the magnetic field direction can be precisely controlled by adjusting the current direction of the electromagnet, the winding method or the rotating angle of the permanent magnet.

[0034] As a preferred embodiment, the drying and curing treatment step in step S5 adopts vacuum drying or freeze drying, and the temperature and time are controlled to avoid damaging the structure of graphene oxide.

[0035] Compared with the prior art, the method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology provided by the present invention has at least the following beneficial effects:

[0036] (1) Through the magnetization orientation technology, the efficient directional arrangement of graphene oxide sheets was successfully achieved; this directional arrangement not only improves the performance of graphene oxide in a specific direction, such as electrical conductivity, thermal conductivity and mechanical strength, but also provides strong support for its application in the fields of high-performance electronic devices and flexible sensors. Compared with traditional methods, the directional arrangement effect of the present invention is more significant and the operation is simpler.

[0037] (2) Comprehensive optimization has been carried out on key steps such as raw material selection and treatment, oxidation reaction control, magnetization treatment and directional arrangement, and drying and curing conditions; these optimization measures not only improve the preparation efficiency, but also reduce the production cost, while ensuring the stability and consistency of product quality. In addition, the present invention also avoids the use of a large amount of harmful chemicals such as strong acids and strong oxidants, reduces environmental pollution, and conforms to the development trend of green chemistry.

[0038] (3) By adopting the preparation method of the present invention, the oriented graphene oxide prepared exhibits excellent performance in terms of electrical conductivity, thermal conductivity, mechanical strength, etc.; the improvement of these properties not only provides more possibilities for the application of graphene oxide in the fields of energy storage and conversion, water treatment, and biosensing, but also promotes the development and innovation of related technologies.

[0039] (4) Due to its unique structure and excellent performance, oriented graphene oxide has broad application prospects in the fields of high-performance electronic devices, flexible sensors, energy storage and conversion, water treatment, and biosensing. The preparation method of the present invention provides high-quality oriented graphene oxide materials for these fields, which helps to promote the progress and application of related technologies. For example, in the field of high-performance electronic devices, oriented graphene oxide can be used to manufacture flexible display screens, wearable devices, etc.; in the field of energy storage and conversion, it can be used for energy storage devices such as supercapacitors and lithium-ion batteries; in the field of water treatment, it can be used to remove heavy metal ions and organic pollutants in water; in the field of biosensing, it can be used for biological molecule detection, disease diagnosis, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention is a schematic flow chart of a method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the embodiments.

[0042] See also Figure 1 The present invention provides a method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology, comprising the following steps:

[0043] S1. Select high-purity graphite powder as the starting material and perform pretreatment, including grinding and screening pretreatment to ensure uniform particle size distribution;

[0044] The purity of the above graphite powder should reach more than 99% to ensure the quality and performance of the final product. The grinding process should use appropriate grinding equipment and processes to ensure that the particle size distribution of the graphite powder is uniform. The screening process is used to remove large particle impurities and further refine the particle size. Usually, the particle size of the graphite powder after screening should be controlled within a certain range to meet the needs of the subsequent oxidation reaction.

[0045] S2. Oxidizing the graphite powder obtained by pretreatment in step S1 into graphene oxide by using an improved Hummers method. The improved Hummers method comprises adding the graphite powder into a cooled mixture of sulfuric acid and concentrated nitric acid, slowly adding potassium permanganate oxidant, controlling the reaction temperature and time, and obtaining graphene oxide by washing and drying after the reaction is completed;

[0046] S3, dispersing the graphene oxide in step S2 in a suitable solvent to form a dispersion. During the dispersion process, sufficient stirring and ultrasonic treatment are required to ensure that the graphene oxide can be evenly dispersed in the solvent. The selection of stirring speed and ultrasonic power should be adjusted according to the characteristics and requirements of the graphene oxide;

[0047] S4, placing the dispersion in step S3 in an external magnetic field, adjusting the magnetic field strength and direction, so that the graphene oxide sheets are oriented. The adjustment of the magnetic field strength and direction needs to be precisely controlled according to the magnetic response characteristics and directional requirements of the graphene oxide. The greater the magnetic field strength, the more obvious the directional alignment effect. However, too high a magnetic field strength may also cause structural damage to the graphene oxide. During the directional alignment process, the concentration and flow rate of the dispersion need to be controlled.

[0048] S5, drying and curing the graphene oxide after the alignment in step S4, wherein the drying and curing steps adopt vacuum drying or freeze drying, and the temperature and time are controlled to avoid damaging the structure of the graphene oxide;

[0049] S6. Characterize the oriented graphene oxide in step S5 using FTIR, SEM, XRD and VSM techniques, and adjust the preparation parameters according to the characterization results. According to the characterization results, key steps such as magnetization treatment parameters (such as magnetic field intensity, treatment time) and drying conditions (such as temperature, time) can be adjusted to further optimize the performance of the oriented graphene oxide. During the optimization process, multiple experimental verifications and comparative analyses are required to determine the optimal preparation process and parameters.

[0050] Furthermore, it is worth specifying that the concentration and dispersion time of the dispersion in step S3 are adjusted according to the characteristics and requirements of the graphene oxide in step S2.

[0051] The concentration of the dispersion can be adjusted by chemical analysis, physical measurement or direct weighing. After the concentration measurement method is determined, the target concentration range can be set according to the characteristics and requirements of graphene oxide (such as conductivity, optical properties, etc.), and the concentration of the dispersion can be accurately adjusted by adjusting the amount of graphene oxide powder added or the amount of solvent used.

[0052] The dispersion time of the dispersion liquid can be adjusted through a series of experiments to observe the dispersion effect of graphene oxide in the solvent at different dispersion times (such as dispersion uniformity, particle size, etc.), so as to determine the optimal dispersion time. Based on the existing experimental data and empirical formula, the dispersion time required at different concentrations can be estimated. The specific formula is:

[0053] t=k*C n

[0054] Where: t is the required dispersion time;

[0055] k is an empirical constant that depends on factors such as experimental conditions, the properties of graphene oxide, and the type of solvent;

[0056] C is the concentration of the dispersion;

[0057] n is the concentration exponent, which describes the nonlinear relationship between dispersion time and dispersion concentration;

[0058] In order to determine the empirical constant k and the concentration exponent n, a series of experiments are required. In each experiment, different dispersion concentrations are used and the time required to achieve a predetermined dispersion effect is measured. These data can then be used to fit the empirical formula to obtain the values ​​of k and n.

[0059] It should be noted that the values ​​of k and n in the empirical formula may vary due to differences in experimental conditions, properties of graphene oxide, and solvent type. Therefore, when using the empirical formula for estimation, it is necessary to ensure that the experimental conditions match the conditions under which the formula applies.

[0060] Furthermore, it is worth specifying that the intensity and direction of the external magnetic field in step S4 are precisely controlled according to the magnetic response characteristics and orientation requirements of the graphene oxide in step S2.

[0061] The magnetic field strength control method can adopt the electromagnet adjustment method and the permanent magnet combination method. After determining the magnetic field strength control method, the target magnetic field strength range can be set according to the magnetic response characteristics and directional requirements of graphene oxide (such as magnetic strength, magnetization direction, etc.), and the magnetic field strength can be precisely controlled by adjusting the current of the electromagnet or the combination of permanent magnets.

[0062] The magnetic field direction control method can adopt the electromagnet direction adjustment method and the permanent magnet rotation method. After determining the magnetic field direction control method, the target magnetic field direction range can be set according to the magnetic response characteristics and directional requirements of graphene oxide (such as directional arrangement direction, magnetization direction, etc.), and the magnetic field direction can be precisely controlled by adjusting the current direction of the electromagnet, the winding method or the rotating angle of the permanent magnet.

[0063] By selecting appropriate concentration and dispersion time adjustment methods and magnetic field strength and direction control methods, and accurately adjusting and controlling according to the characteristics and needs of graphene oxide, it is possible to achieve precise control of dispersion liquid concentration, dispersion time, and external magnetic field strength and direction, which will help improve the dispersion and directional arrangement effects of graphene oxide, and provide strong support for the widespread application of graphene oxide.

[0064] This scheme has the following working process: first, high-quality graphite powder is selected as the starting raw material to ensure that the purity of the graphite powder reaches more than 99% and the particle size distribution is uniform. The graphite powder is pretreated, such as grinding, screening, etc., to further refine the particle size and remove impurities, so as to provide a good basis for the subsequent oxidation reaction; secondly, the improved Hummers method is used to synthesize graphene oxide, frozen concentrated nitric acid is added to the cooled sulfuric acid, and the pretreated graphite powder is slowly added to the mixture of sulfuric acid and nitric acid, and fully stirred, and then, potassium permanganate and other oxidants are slowly added, and the reaction temperature and time are controlled to fully oxidize the graphite powder. After the reaction is completed, the product is poured into cold water to stop the reaction and produce precipitation, and the precipitation is repeatedly washed with dilute sulfuric acid and water until the pH value of the washing water is neutral. Finally, the washed precipitation is dried in a vacuum dryer to obtain graphene oxide.

[0065] Then, by adjusting the amount of oxidant and the reaction time, the oxidation degree of graphene oxide is precisely controlled to obtain graphene oxide with ideal functional group types and distribution. The graphene oxide is dispersed in an appropriate solvent, such as deionized water or ethanol, to form a uniform dispersion. The concentration and dispersion time of the dispersion need to be adjusted according to the characteristics and requirements of the graphene oxide. The dispersion is placed in an external magnetic field, and the magnetic field strength and direction are adjusted so that the graphene oxide sheets are gradually oriented under the action of the magnetic field. The adjustment of the magnetic field strength and direction needs to be precisely controlled according to the magnetic response characteristics and directional requirements of the graphene oxide. The directional arrangement effect of the graphene oxide is observed by testing methods such as SEM to ensure that the sheets are orderly arranged under the action of the magnetic field. The magnetized graphene oxide dispersion is dried by vacuum drying or freeze drying to maintain its oriented structure. The temperature and time need to be controlled during the drying process to avoid damage to the structure of the graphene oxide. A certain pressure or temperature is applied to the dried graphene oxide sample to further consolidate its oriented structure and improve the stability and performance of the product.

[0066] Finally, the oxidation degree, interplanar spacing, functional group types and distribution, morphology and particle size distribution of oriented graphene oxide were comprehensively and systematically characterized using a variety of advanced testing techniques such as FTIR, SEM, XRD and VSM. These characterization results provide a scientific basis for subsequent performance optimization. According to the characterization results, key steps such as magnetization treatment parameters (such as magnetic field intensity, treatment time) and drying conditions (such as temperature, time) are adjusted to further optimize the performance of oriented graphene oxide. At the same time, different solvents, dispersants and subsequent treatment methods can also be tried to further improve the quality and performance of the product.

[0067] In summary: Through the magnetization orientation technology, efficient directional arrangement of graphene oxide sheets was successfully achieved; this directional arrangement not only improved the performance of graphene oxide in a specific direction, such as electrical conductivity, thermal conductivity and mechanical strength, but also provided strong support for its application in the fields of high-performance electronic devices, flexible sensors, etc.; comprehensive optimization was carried out on key steps such as raw material selection and treatment, oxidation reaction control, magnetization treatment and directional arrangement, and drying and curing conditions; by adopting the preparation method of the present invention, the prepared oriented graphene oxide showed excellent performance in terms of electrical conductivity, thermal conductivity, mechanical strength, etc.; due to its unique structure and excellent performance, oriented graphene oxide has broad application prospects in the fields of high-performance electronic devices, flexible sensors, energy storage and conversion, water treatment, and biosensors.

Claims

1. A method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology, characterized in that: The following steps are involved: S1, select high purity graphite powder as starting material, and carry out pretreatment; S2, oxidizing the graphite powder obtained by pretreatment in step S1 into graphene oxide by using an improved Hummers method; S3, dispersing the graphene oxide in step S2 in a suitable solvent to form a dispersion; S4, placing the dispersion in step S3 in an external magnetic field, adjusting the strength and direction of the magnetic field to align the graphene oxide sheets; S5, drying and curing the graphene oxide after the alignment in step S4; S6. Characterize the oriented graphene oxide in step S5 using FTIR, SEM, XRD and VSM techniques, and adjust the preparation parameters according to the characterization results.

2. The method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology according to claim 1, characterized in that: The pretreatment in step S1 includes grinding and screening pretreatment to ensure uniform particle size distribution.

3. The method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology according to claim 2, characterized in that: The improved Hummers method described in step S2 includes adding graphite powder to a cooled mixture of sulfuric acid and concentrated nitric acid, slowly adding potassium permanganate oxidant, controlling the reaction temperature and time, and obtaining graphene oxide by washing and drying after the reaction is completed.

4. The method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology according to claim 3, characterized in that: The concentration and dispersion time of the dispersion in step S3 are adjusted according to the characteristics and requirements of the graphene oxide in step S2.

5. The method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology according to claim 4, characterized in that: The intensity and direction of the external magnetic field in step S4 are precisely controlled according to the magnetic response characteristics and orientation requirements of the graphene oxide in step S2.

6. The method for preparing oriented graphene oxide based on graphene oxide magnetization orientation technology according to claim 5, characterized in that: The drying and curing treatment step in step S5 adopts vacuum drying or freeze drying, and the temperature and time are controlled to avoid damaging the structure of the graphene oxide.

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