Method for electrochemical one-step synthesis of two-dimensional graphene and boronene / tellurene composite

Abstract

This invention discloses a one-step electrochemical synthesis method for two-dimensional graphene and borene / tellurene composites, comprising the following steps: placing a graphite electrode and a boron / tellurene block electrode as the anode and cathode, respectively, in an electrolyte; connecting a power source to the cathode and anode to form an electrolytic cell structure; electrolyzing at a constant voltage of 5–20V for 30 min–100 h under stirring; then washing and centrifuging to obtain a solution of two-dimensional graphene and borene / tellurene composites, or washing and drying to obtain the two-dimensional graphene and borene / tellurene composites. This invention reduces the possibility of material contamination, improves synthesis efficiency, and enhances the bonding between the two two-dimensional materials, thereby effectively improving the electrical properties of borene / tellurene and providing the possibility of fully exhibiting its inherent properties. This method is simple, low-cost, environmentally friendly, efficient, and suitable for large-scale synthesis.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical technology and relates to a method for preparing two-dimensional composite materials, specifically a one-step electrochemical synthesis method for two-dimensional graphene and borene / tellurene composites. Background Technology

[0002] Novel two-dimensional nanomaterials, borophene and tellurene, possess excellent mechanical strength and flexibility, as well as a lower density compared to graphene. They are also excellent conductors of electricity and heat. Furthermore, the unique layered structure of two-dimensional materials endows these novel two-dimensional materials with enormous application potential in hydrogen production, lithium batteries, supercapacitors, high-speed transistors, and optoelectronic devices. In recent years, research on borophene and tellurene has gradually attracted attention, but experimental studies on the synthesis of two-dimensional borophene and tellurene are currently scarce. In summary, current preparation methods mainly include chemical vapor deposition, molecular beam epitaxy, thermal decomposition, and liquid phase exfoliation. However, these methods still encounter various drawbacks, such as the need for ultra-high vacuum, additional transfer steps, high cost, and low yield, which limit their in-depth research and application. Therefore, it is essential to develop a simple and effective method for the large-scale preparation of high-quality few-layer borophene and tellurene nanosheets. To date, electrochemical exfoliation has been proven to be an efficient method for the preparation of many two-dimensional materials, such as graphene, MoS2, Bi2Se3, Bi2Te3, and black phosphorus. However, its application in the preparation of two-dimensional borophene and tellurene has not yet been explored.

[0003] Furthermore, these two types of two-dimensional materials are semiconductors with poor conductivity, which hinders carrier migration in practical applications such as electrochemical energy storage, electrocatalysis, and photocatalysis. Many of their superior properties are limited by their poor conductivity. Combining various two-dimensional semiconductor materials with conductive graphene to construct functionalized composite materials has become an important strategy for improving their performance. Currently, this research has been extensively conducted on various materials, including transition metal dihalogen compounds (e.g., MoS2, WSe2), transition metal oxides (e.g., MnO2, MoO3), graphitic carbonitrides (g-C3N4), hexagonal boronitrides, transition metal carbides (MXenes), and black phosphorus.

[0004] The preparation of such graphene-based composite materials typically involves mixing two separate two-dimensional materials, or forming other components in situ in the presence of graphene. However, the synthesis results from mixing two separate two-dimensional materials are relatively poor because the surfaces of the two-dimensional layered materials are easily contaminated, resulting in weak chemical and electronic interactions between them. This reduces their reactivity and affects the performance of the synthesized material.

[0005] However, there is still no simple and efficient method for synthesizing graphene and borene / tellurene composites. Summary of the Invention

[0006] To address the problems in the prior art, the purpose of this invention is to provide a one-step electrochemical method for synthesizing two-dimensional graphene and borene / tellurene composites. This method is a one-step process that is simple, efficient, low-cost, and can achieve in-situ composite synthesis of two-dimensional materials.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An electrochemical one-step method for synthesizing two-dimensional graphene and borene / tellurene complexes includes the following steps:

[0009] Graphite electrodes and boron / tellurium block electrodes are used as anodes and cathodes, respectively, and placed in the electrolyte. The power supply is connected to the cathode and anode to form an electrolytic cell structure.

[0010] Electrolyze at a constant voltage of 5–20V for 30 min–100 h under stirring, then wash and centrifuge to obtain a solution of two-dimensional graphene and boronene / tellurene composite, or wash and dry to obtain a solution of two-dimensional graphene and boronene / tellurene composite.

[0011] Furthermore, the electrolyte is prepared by adding one or both of quaternary alkyl tetrafluoroborate ammonium with 1-6 carbon atoms and quaternary alkyl hexafluorophosphate ammonium to a solvent to obtain an electrolyte with a concentration of 0.01-2 mol / L.

[0012] Furthermore, the solvent, by mass percentage, includes 20-33% ethylene carbonate, 33-40% dimethyl carbonate, and 33-45% diethyl carbonate.

[0013] Furthermore, the electrolyte also includes additives.

[0014] Furthermore, the additive is one or more of lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(fluorosulfonyl)imide.

[0015] Furthermore, the solubility of the additive in the electrolyte is 0.001-0.01 mol / L.

[0016] Furthermore, the anode and cathode are 2-3 cm apart, and both the anode and cathode extend 3-5 cm into the electrolyte.

[0017] Furthermore, the stirring speed is 50–500 rpm.

[0018] Furthermore, graphite can be natural flake graphite, microcrystalline graphite, artificial graphite, highly oriented pyrolytic graphite, graphite rods, or graphite foil.

[0019] Furthermore, electrolyze under constant voltage of 5–20V for 30–60 minutes with stirring.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention proposes a method for simultaneously exfoliating two-dimensional materials, graphene and borene / tellurene, in a single electrolytic cell via electrochemical anode and cathode, and for the production of high-performance two-dimensional composite materials. This method uses graphite and borene / tellurene blocks as the anode and cathode electrodes, respectively, and employs an electrochemical bipolar exfoliation method to simultaneously synthesize graphene and borene / tellurene in an electrolytic cell. This achieves direct composite formation of the semiconductor-grade two-dimensional materials borene / tellurene and graphene in solution. Compared to the traditional liquid-phase mixing method (which involves preparing the two two-dimensional materials separately, cleaning them, and then mixing them in the liquid phase), this method reduces the possibility of material contamination, improves synthesis efficiency, and enhances the bonding between the two two-dimensional materials. This effectively improves the electrical properties of borene / tellurene and provides the possibility of fully exhibiting its inherent properties. This method is simple, low-cost, environmentally friendly, highly efficient, and suitable for large-scale synthesis. It is widely applicable to exfoliating various layered materials to generate two-dimensional nanosheets and various composite materials, which will contribute to the application of two-dimensional materials such as borene and tellurene in electro / photocatalysis, energy conversion and storage, and flexible electronics.

[0022] Furthermore, the solvents in this invention include ethylene carbonate, dimethyl carbonate, and diethyl carbonate. In an electrolyte with a wide electrochemical stability potential window, graphene and borene / tellurene two-dimensional material "precursors" are simultaneously exfoliated on the anode and cathode electrodes by electrochemical methods, thereby achieving the synchronous synthesis of graphene and borene. The two-dimensional materials are then composited in situ in the electrolyte by utilizing the mutual attraction between them, thus achieving efficient production of composite materials in a one-pot process.

[0023] Furthermore, adding one or more of the following additives to the electrolyte, such as lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(fluorosulfonyl)imide, can increase the conductivity of the solution and improve the stripping efficiency of anions on the anode graphite electrode. Attached Figure Description

[0024] Figure 1 A schematic diagram illustrating the principle of simultaneous electrochemical anode-cathode exfoliation for the preparation of graphene and borene / tellurene composites.

[0025] Figure 2 This is a diagram illustrating the electrochemical one-step simultaneous exfoliation preparation of graphene / boronene composites in an electrolyte (0.5 mol / L tetrabutylammonium hexafluorophosphate + 0.001 mol / L lithium trifluoromethanesulfonate electrolyte) in Example 1.

[0026] Figure 3This is a diagram illustrating the electrochemical one-step preparation of graphene / tellurene composites in Example 2 using an organic electrolyte composed of 0.1 mol / L tetraethylammonium tetrafluoroborate, 0.002 mol / L lithium bis(trifluoromethanesulfonyl)imide / ethylene carbonate (33.3%), dimethyl carbonate (33.3%), and diethyl carbonate (33.4%).

[0027] Figure 4 The graphene dispersion obtained by anode exfoliation, the boronene dispersion obtained by cathode exfoliation, and the graphene / boronene composite synthesized by simultaneous anode and cathode exfoliation in Example 1 are described below. In this example, (a) represents graphene, (b) represents boronene, and (c) represents the graphene / boronene composite.

[0028] Figure 5 The graphene dispersion exfoliated from the anode, the tellurene dispersion exfoliated from the cathode, and the dispersion of the synthesized graphene / tellurene composite are described in Example 2. Wherein, (a) is graphene, (b) is tellurene, and (c) is the graphene / tellurene composite.

[0029] Figure 6 These are optical micrographs of graphene / boronene composites and graphene / tellurene composites. (a) shows the graphene / boronene composite, and (b) shows the graphene / tellurene composite. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings.

[0031] Ideally, the composite of two-dimensional layered materials should be synthesized in situ during the formation of the two-dimensional layered material precursor to minimize potential contamination while maximizing the utilization of their chemical and electronic interactions.

[0032] The electrochemical one-step synthesis method for two-dimensional graphene and borene / tellurene composites of the present invention is based on the following principle: Figure 1 As shown, in the electrolytic cell, the electric field drives the anions and cations to embed between the graphite anode and the boron / tellurium cathode layers, respectively, and generates structural expansion of the cathode and anode electrodes. In addition, the force of the gas generated by ion decomposition leads to the simultaneous formation of graphene and borene / tellurene in the solution. In the electrolyte cell, the mutual attraction between the layers of graphene and borene / tellurene, two two-dimensional olefinic materials, promotes their combination to form a composite.

[0033] The electrochemical one-step synthesis method of two-dimensional graphene and borene / tellurene composites of the present invention includes the following steps:

[0034] (1) Preparation of electrolyte for electrochemical simultaneous stripping:

[0035] 1.1 The electrolyte composition is as follows: The electrolyte includes a solute and a solvent. The solute is one or both of quaternary alkyl tetrafluoroborate ammonium and quaternary alkyl hexafluorophosphate ammonium with 1-6 carbon atoms (methyl-hexyl). The solvent, by mass percentage, includes ethylene carbonate (20-33%), dimethyl carbonate (33-40%), and diethyl carbonate (33-45%). The mixed solvent formed by these three has a wider potential window and is more suitable for simultaneous stripping of the anode and cathode. In addition, in order to increase the conductivity of the solution and improve the stripping efficiency of anions on the anode graphite electrode, one or more of the following additives, such as lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(fluorosulfonyl)imide, are added to the prepared electrolyte. The concentration of the additives in the electrolyte is 0.001-0.01 mol / L.

[0036] 1.2 Dissolve the solute in a solvent to obtain a solution with a molar concentration of 0.01-2 mol / L. Then add the additive and stir on a magnetic stirrer to form a completely dissolved transparent solution, which is the electrolyte.

[0037] (2) Take a graphite electrode and a boron / tellurium block electrode as the anode and cathode, respectively, and put 50-100 mL of electrolyte into a beaker to form an electrolytic cell structure. The anode and cathode are 2-3 cm apart and extend 3-5 cm into the electrolyte.

[0038] (3) Connect the power supply to the cathode and anode, turn on the power supply, and electrolyze at a constant voltage of 5-20V for a sufficient time (30min-100h). Use a magnetic stirrer to continuously stir the electrolyte at a speed of 50-500rpm. The purpose is to ensure that the exfoliated boronene / tellurene and graphene can be fully mixed in the electrolyte and achieve in-situ composite until enough products are produced.

[0039] (4) After the stripping is completed, the stripped product is washed by filtration (more than 5 times) with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0040] (5) Disperse the filter cake of the cleaned complex in N,N-dimethylformamide or N-methylpyrrolidone organic solvent and sonicate it in an ultrasonicator for 30 min. Then centrifuge the dispersion at a speed of 2000-5000 rpm for 30 min, and extract the supernatant for preservation or dry the solution to obtain the complex powder.

[0041] The graphite used in the steps can be natural flake graphite, microcrystalline graphite, artificial graphite, highly oriented pyrolytic graphite, graphite rods, or graphite foil. The boron and tellurium electrodes are irregularly shaped blocks or electrodes of various shapes formed by pressing powder.

[0042] Example 1

[0043] (1) Preparation of the electrolyte for electrochemical stripping:

[0044] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 25 wt% ethylene carbonate, 35 wt% dimethyl carbonate, and 40 wt% diethyl carbonate. The solute is tetrabutylammonium hexafluorophosphate with a concentration of 0.5 mol / L. The additive is lithium trifluoromethanesulfonate with a solubility of 0.001 mol / L. Weigh the solvent, solute, and additive according to the above proportions, and completely dissolve the solute and additive by magnetic stirring to form the electrolyte used.

[0045] (2) Take 80 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the anode and cathode is 2 cm, the anode extends 5 cm into the electrolyte, and the cathode extends 3 cm into the electrolyte.

[0046] (3) Connect the power supply to the cathode and anode, turn on the power supply, electrolyze at a constant voltage of 15V for 30 minutes, and use a magnetic stirrer to continuously stir in the electrolyte (100rpm) to achieve in-situ composite of borene and graphene in the electrolyte.

[0047] Depend on Figure 2 It can be seen that after pressurizing in the electrolyte cell for 10 minutes, both the cathode boron electrode and the anode graphite electrode showed obvious peeling, and after 30 minutes, the two peeled materials were uniformly mixed.

[0048] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0049] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 2000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and boronene composite solution.

[0050] from Figure 4 It can be seen that the electrochemical exfoliation method of the present invention can effectively obtain dispersions of individual graphene, borene, and their composites.

[0051] At the same time from Figure 6 The light microscopy image of the composite dispersion in (a) verifies that the electrochemical bipolar exfoliation of the present invention can not only achieve the simultaneous acquisition of two two-dimensional materials, borene and graphene, but also that the two can organically combine in solution to form a composite.

[0052] Example 2

[0053] (1) The electrolyte used for electrochemical dual-electrode stripping is formulated as follows: The electrolyte includes solvent, additive and solute. The solvent, by mass percentage, includes 33.3 wt% ethylene carbonate, 33.3 wt% dimethyl carbonate and 33.4 wt% diethyl carbonate; the solute is tetraethylammonium tetrafluoroborate with a solute concentration of 0.1 mol / L; the additive is lithium bis(trifluoromethanesulfonyl)imide with an additive concentration of 0.002 mol / L. The solvent, solute and additive are weighed according to the above proportions, and the solute and additive are completely dissolved in the solvent by magnetic stirring to form the electrolyte.

[0054] (2) Take 60 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block-shaped tellurium as the cathode to form an electrolytic cell structure. The distance between the cathode and anode is 2 cm, and the anode extends 4 cm into the electrolyte, while the cathode extends 2 cm into the electrolyte.

[0055] (3) Connect the power supply to the cathode and anode, turn on the power supply, and electrolyze at a constant voltage of 15V for 30 minutes. Use a magnetic stirrer to continuously stir the electrolyte (150rpm) to achieve in-situ composite of tellurene and graphene in the electrolyte.

[0056] Depend on Figure 3 It can be seen that after pressurizing in the electrolyte cell for 10 minutes, both the cathode tellurium block and the anode graphite electrode showed obvious stripping, and both cathode and anode products were suspended in the solution. After 30 minutes, the two stripped materials formed a uniform mixture.

[0057] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0058] (5) The purified tellurene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 2000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and tellurene composite solution.

[0059] from Figure 5 As can be seen from (a), (b) and (c), the electrochemical exfoliation method of the present invention can effectively obtain dispersions of individual graphene, tellurene, and tellurene / graphene composites.

[0060] At the same time from Figure 6 The light microscopy image of the composite material in (b) verifies that the electrochemical bipolar exfoliation of the present invention can not only simultaneously obtain two two-dimensional material nanosheets, tellurene and graphene, but also that the two can organically combine in solution to form a composite material.

[0061] Example 3

[0062] (1) Preparation of the electrolyte for electrochemical stripping:

[0063] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 20wt% ethylene carbonate, 40wt% dimethyl carbonate, and 44wt% diethyl carbonate. The solute is tetramethylammonium hexafluorophosphate with a concentration of 0.01mol / L. The additive is lithium trifluoromethanesulfonate with a solubility of 0.001mol / L. The solvent, solute, and additive are weighed according to the above proportions, and the solute and additive are completely dissolved by magnetic stirring to form the electrolyte used.

[0064] (2) Take 50 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block-shaped tellurium as the cathode to form an electrolytic cell structure. The distance between the cathode and anode is 2 cm, the anode extends 3 cm into the electrolyte, and the cathode extends 3 cm into the electrolyte.

[0065] (3) Connect the power supply to the cathode and anode, turn on the power supply, electrolyze at a constant voltage of 5V for 100h, and use a magnetic stirrer to continuously stir in the electrolyte (50rpm) to achieve in-situ composite of tellurene and graphene in the electrolyte.

[0066] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0067] (5) The cleaned tellurene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 2000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and tellurene composite solution.

[0068] Example 4

[0069] (1) Preparation of the electrolyte for electrochemical stripping:

[0070] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 33wt% ethylene carbonate, 33wt% dimethyl carbonate, and 34wt% diethyl carbonate. The solute is tetraethylammonium hexafluorophosphate with a concentration of 0.05mol / L. The additive is lithium bis(trifluoromethanesulfonyl)imide with a solubility of 0.01mol / L. Weigh the solvent, solute, and additive according to the above proportions, and completely dissolve the solute and additive by magnetic stirring to form the electrolyte used.

[0071] (2) Take 100 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the anode and cathode is 3 cm, and the anode extends 4 cm into the electrolyte and the cathode extends 3 cm into the electrolyte.

[0072] (3) Connect the power supply to the cathode and anode, turn on the power supply, electrolyze at a constant voltage of 20V for 30 minutes, and use a magnetic stirrer to continuously stir in the electrolyte (500rpm) to achieve in-situ composite of boronene and graphene in the electrolyte.

[0073] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0074] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 5000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and boronene composite solution.

[0075] Example 5

[0076] (1) Preparation of the electrolyte for electrochemical stripping:

[0077] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 25 wt% ethylene carbonate, 35 wt% dimethyl carbonate, and 40 wt% diethyl carbonate. The solute is tetrahexyl hexafluorophosphate with a concentration of 0.1 mol / L. The additive is lithium difluorosulfonylimide with a solubility of 0.003 mol / L. Weigh the solvent, solute, and additive according to the above proportions, and completely dissolve the solute and additive by magnetic stirring to form the electrolyte used.

[0078] (2) Take 60 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the anode and cathode is 3 cm, and the anode extends 5 cm into the electrolyte, while the cathode extends 3 cm into the electrolyte.

[0079] (3) Connect the power supply to the cathode and anode, turn on the power supply, and electrolyze at a constant voltage of 10V for 50 hours. Use a magnetic stirrer to continuously stir the electrolyte (300rpm) to achieve in-situ composite of boronene and graphene in the electrolyte.

[0080] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0081] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 3000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and boronene composite solution.

[0082] Example 6

[0083] (1) Preparation of the electrolyte for electrochemical stripping:

[0084] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 20wt% ethylene carbonate, 35wt% dimethyl carbonate, and 45wt% diethyl carbonate. The solute is tetrabutylammonium tetrafluoroborate with a concentration of 0.3mol / L. The additive is a mixture of lithium trifluoromethanesulfonate and lithium bis(trifluoromethanesulfonyl)imide in any proportion with a solubility of 0.006mol / L. The solvent, solute, and additive are weighed according to the above proportions, and the solute and additive are completely dissolved by magnetic stirring to form the electrolyte used.

[0085] (2) Take 70 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the anode and cathode is 3 cm, and the anode extends 5 cm into the electrolyte and the cathode extends 4 cm into the electrolyte.

[0086] (3) Connect the power supply to the cathode and anode, turn on the power supply, electrolyze at a constant voltage of 7V for 80h, and use a magnetic stirrer to continuously stir in the electrolyte (200rpm) to achieve in-situ composite of boronene and graphene in the electrolyte.

[0087] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0088] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 2000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and boronene composite solution.

[0089] Example 7

[0090] (1) Preparation of the electrolyte for electrochemical stripping:

[0091] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 20wt% ethylene carbonate, 38wt% dimethyl carbonate, and 42wt% diethyl carbonate. The solute is tetramethylammonium tetrafluoroborate with a concentration of 0.8mol / L. The additive is a mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide in any proportion with a solubility of 0.008mol / L. The solvent, solute, and additive are weighed according to the above proportions, and the solute and additive are completely dissolved by magnetic stirring to form the electrolyte used.

[0092] (2) Take 90 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the anode and cathode is 2 cm, and the anode extends 5 cm into the electrolyte, while the cathode extends 5 cm into the electrolyte.

[0093] (3) Connect the power supply to the cathode and anode, turn on the power supply, electrolyze at a constant voltage of 15V for 30 minutes, and use a magnetic stirrer to continuously stir in the electrolyte (400rpm) to achieve in-situ composite of boronene and graphene in the electrolyte.

[0094] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0095] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 4000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and boronene composite solution.

[0096] Example 8

[0097] (1) Preparation of the electrolyte for electrochemical stripping:

[0098] The electrolyte formulation is as follows: The electrolyte includes solvent, additives, and solute. The solvent, by mass percentage, includes 28wt% ethylene carbonate, 39wt% dimethyl carbonate, and 33wt% diethyl carbonate. The solute is tetrapropylammonium tetrafluoroborate with a solute concentration of 1.5mol / L. The additive is lithium trifluoromethanesulfonate with an additive concentration of 0.005mol / L. Weigh the solvent, solute, and additive according to the above proportions, and completely dissolve the solute and additive by magnetic stirring to form the electrolyte used.

[0099] (2) Take 100 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the cathode and anode is 2 cm, and the anode extends 5 cm into the electrolyte, while the cathode extends 4 cm into the electrolyte.

[0100] (3) Connect the power supply to the cathode and anode, turn on the power supply, electrolyze at a constant voltage of 18V for 60 minutes, and use a magnetic stirrer to continuously stir in the electrolyte (500 rpm) to achieve in-situ composite of borene and graphene in the electrolyte.

[0101] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0102] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 2000 rpm for 30 min, the supernatant was extracted, and dried to obtain the two-dimensional graphene and boronene composite.

[0103] Example 9

[0104] (1) Preparation of the electrolyte for electrochemical stripping:

[0105] The electrolyte formulation is as follows: The electrolyte includes a solvent and a solute. The solvent, by mass percentage, includes 33 wt% ethylene carbonate, 33 wt% dimethyl carbonate, and 37 wt% diethyl carbonate. The solute is tetrahexyltetrafluoroborate ammonium, with a solute concentration of 2 mol / L. Weigh the solvent, solute, and additives according to the above proportions, and completely dissolve the solute and additives by magnetic stirring to form the electrolyte used.

[0106] (2) Take 80 mL of the prepared electrolyte solution and put it into a beaker. Use rod-shaped graphite as the anode and block boron as the cathode to form an electrolytic cell structure. The distance between the anode and cathode is 2 cm, the anode extends 45 cm into the electrolyte, and the cathode extends 3 cm into the electrolyte.

[0107] (3) Connect the power supply to the cathode and anode, turn on the power supply, and electrolyze at a constant voltage of 18V for 20 hours. Use a magnetic stirrer to continuously stir the electrolyte (250rpm) to achieve in-situ composite of boronene and graphene in the electrolyte.

[0108] (4) After the stripping reaction is completed, the product is repeatedly filtered and washed 5 times with ultrapure water and ethanol to remove impurities such as electrolyte adsorbed on the surface of the two-dimensional material.

[0109] (5) The cleaned boronene / graphene composite was dispersed in N,N-dimethylformamide and sonicated for 30 min. The resulting dispersion was then centrifuged at 2000 rpm for 30 min, and the supernatant was extracted and stored to obtain a two-dimensional graphene and boronene composite solution.

[0110] This invention provides a one-pot method for simultaneously preparing borene / tellurene and graphene and directly forming composites. Specifically, in the same electrolytic cell, using an electrolyte with a wide electrochemical window, graphene is simultaneously generated by anodic exfoliation and borene / tellurene by cathodic exfoliation. The two materials then combine in situ in the electrolyte to form a two-dimensional composite material. The excellent conductivity of graphene in this composite improves the electrical properties of both borene and tellurene and helps them exhibit their intrinsic properties. This simple, efficient, and low-cost method for synthesizing graphene / borene and graphene / tellurene two-dimensional composites will promote their widespread application in catalysis, electronics, energy storage, and conversion.

Claims

1. A method for one-step electrochemical synthesis of two-dimensional graphene and borene / tellurene composites, characterized in that, Includes the following steps: Graphite electrodes and boron / tellurium block electrodes are used as anodes and cathodes, respectively, and placed in the electrolyte. The power supply is connected to the cathode and anode to form an electrolytic cell structure. The electrolyte is prepared by the following process: adding one or both of quaternary alkyl tetrafluoroborate ammonium with 1-6 carbon atoms and quaternary alkyl hexafluorophosphate ammonium to a solvent to obtain an electrolyte with a concentration of 0.01-2 mol / L; the solvent, by mass percentage, includes 20-33% ethylene carbonate, 33-40% dimethyl carbonate, and 33-45% diethyl carbonate; the electrolyte also includes additives, which are one or more of lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(fluorosulfonyl)imide; the solubility of the additives in the electrolyte is 0.001-0.01 mol / L; Electrolysis was carried out at a constant voltage of 5–20 V for 30 min–100 h under stirring. After washing and centrifugation, a solution of two-dimensional graphene and boronene / tellurene composite was obtained, or a solution of two-dimensional graphene and boronene / tellurene composite was obtained after washing and drying.

2. The method for one-step electrochemical synthesis of two-dimensional graphene and borene / tellurene composites according to claim 1, characterized in that, The anode and cathode are 2-3 cm apart, and both extend 3-5 cm into the electrolyte.

3. The method for one-step electrochemical synthesis of two-dimensional graphene and borene / tellurene composites according to claim 1, characterized in that, The stirring speed is 50-500 rpm.

4. The method for one-step electrochemical synthesis of two-dimensional graphene and borene / tellurene composites according to claim 1, characterized in that, Graphite includes natural flake graphite, microcrystalline graphite, artificial graphite, highly oriented pyrolytic graphite, graphite rods, or graphite foil.

5. The method for one-step electrochemical synthesis of two-dimensional graphene and borene / tellurene composites according to claim 1, characterized in that, Electrolyze at a constant voltage of 5–20 V for 30–60 minutes with stirring.

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