CN104649253A - Preparing methods of porous graphene and porous graphene film - Google Patents

Abstract

The invention provides a preparing method of porous graphene. The method includes: mixing graphene and/or graphene oxide with an etching agent to obtain a mixture; and under oxygen-free conditions, subjecting the mixture to a carbothermic reaction and performing acid processing to remove the reacted and unreacted etching agent, wherein the etching agent is one or more of oxometallate, metal hydroxide and metal oxide. Based on the preparing method of the porous graphene, the invention also provides a preparing method of a porous graphene film by etching a graphene film. By dispersing an etching agent on the graphene film, and performing pore forming research through high-temperature treatment or electron beam radiation, a porous graphene film material is prepared. The pore size on the surface of the prepared porous graphene ranges from 1 nm to 200 nm, and can be regulated and controlled by adjusting the concentration or the size of the etching agent. The porous graphene is high in yield. Operation equipment is simple. A production cost is low.

Description

A kind of preparation method of porous graphene and porous graphene film

technical field

The invention relates to a method for preparing porous graphene and a porous graphene film.

Background technique

Graphene has excellent electrical, thermal and mechanical properties, and has a high theoretical specific surface area (theoretical calculation value is 2600m ² /g). In the past few years, many methods have been used to prepare graphene, including chemical vapor deposition, epitaxial growth, physical exfoliation, chemical reduction, liquid-phase ultrasonic exfoliation, and bottom-up synthesis. Among them, the chemical reduction method is currently the most widely used method for preparing graphene in the field of materials science. The chemical reduction method is also called the reduced graphene oxide method. According to the reduction method, it can be divided into chemical reagent reduction, electrochemical reduction, high temperature thermal reduction, solvothermal reduction and photochemical reduction. The surface of graphene oxide contains a variety of oxygen-containing functional groups and defects. After reduction, most of the oxygen-containing functional groups can be removed, but the defects will still remain on the graphene sheet. In order to obtain more perfect graphene, methods such as chemical vapor deposition are used to repair the defects on the surface of graphene prepared by chemical reduction.

Porous graphene is the introduction of nanoscale pores on the graphene sheet structure (Xu, P.; Yang, J.; Wang, K.; Zhou, Z.; Shen, P. Porous Graphene: Properties, Preparation, and Potential Applications.Chin.Sci.Bull.2012,57(23),2948-2955.), that is, the product obtained by designing and processing the "defects" on the surface of graphene. The research on porous graphene is the utilization of its surface defect structure. Based on the excellent performance and two-dimensional nanostructure of graphene, the pore structure on the surface of porous graphene can endow it with new properties and applications, such as gas separation and purification, DNA sequencing, seawater desalination, and ion channels.

At present, porous graphene mainly uses high-energy substances to bombard or irradiate graphene sheets, and etches to obtain nanoscale pore structures. These high-energy substances include helium ions, electron beams and lasers. However, because these methods require certain equipment, high cost, and low yield, the research work on porous graphene is mainly concentrated in the field of computing science and device research, and there are relatively few studies on its performance in the field of materials. Therefore, developing a simple and efficient method for preparing porous graphene and realizing the large-scale preparation of porous graphene is of great significance for the research and application of porous graphene in the field of material science.

Contents of the invention

The object of the present invention is to provide a simple and efficient method for preparing porous graphene and a method for preparing porous graphene membrane.

Carbothermal reaction is a classic chemical reaction. Under high temperature conditions, most compounds containing metal and oxygen can be reduced by carbon to low-valence metal oxides or metal elements, and even form metal carbides. In a carbothermal reaction, carbon is used as a reducing agent and is oxidized by a compound containing metal and oxygen to produce carbon monoxide or carbon dioxide. The inventors of the present invention unexpectedly found that nanomaterials have high surface energy, and graphene, as a two-dimensional carbon nanomaterial, can generate carbon heat at a relatively low temperature with metal and oxygen compound nanoparticles reaction. Since graphene is a two-dimensional nanostructure formed by a single layer of carbon atoms, after the surface carbon atoms are oxidized, defects, that is, pore structures, are left on the surface to form porous graphene.

Based on the above findings, the present invention provides a method for preparing porous graphene, wherein the method includes mixing graphene and/or graphene oxide with an etchant to obtain a mixture; Carbothermal reaction is carried out, and acid treatment is carried out to remove unreacted or reacted etchant; the etchant is one or more of metal oxo salt, metal hydroxide and metal oxide.

The present invention also provides a method for preparing a porous graphene film, wherein the method comprises: dispersing an etchant on the graphene and/or graphene oxide film, and performing carbon thermal reaction or electronic Beam etching, and acid treatment to remove the reacted or etched etchant; the etchant is one or more of metal oxo salts, metal hydroxides and metal oxides.

The porous graphene provided by the invention has a pore diameter between 1-200nm and a porosity rate of 5-80%.

The research on porous graphene enriches the category of graphene derivatives, and effectively utilizes the defect structure on the surface of graphene derivatives. In lithium-ion batteries, supercapacitor electrodes, catalytic materials and other systems involving component migration, it can effectively Improving the diffusion and migration of electrolyte or reactants is beneficial to the improvement of material properties.

Other features and advantages of the present invention will be described in detail in the following detailed description.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention. In the attached picture:

Fig. 1 is the TEM photograph of the porous graphene sample that embodiment 1.1 prepares;

Fig. 2 is the TEM photograph of the porous graphene sample that embodiment 2.7 prepares;

Fig. 3 is the SEM photograph of the porous graphene sample that embodiment 3.1 prepares;

Fig. 4 is the SEM photo of the porous graphene film sample prepared by embodiment 6.1;

Fig. 5 is the SEM photo of the porous graphene film sample prepared in Example 7.1.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

In the present invention, the term "graphene oxide" refers to graphene with oxygen-containing functional groups.

The invention provides a method for preparing porous graphene, wherein the method comprises: mixing graphene and/or graphene oxide with an etchant to obtain a mixture; and performing a carbothermal reaction on the mixture under an oxygen-free condition , and carry out acid treatment to remove unreacted and reacted etchant; the etchant is one or more of metal oxo-salt, metal hydroxide and metal oxide.

According to the method of the present invention, as long as graphene and/or graphene oxide is mixed with etchant, carbon thermal reaction is carried out under oxygen-free conditions and acid treatment is carried out to remove unreacted and reacted etchant Can obtain porous graphene, the present invention does not have special requirement to the consumption of graphene and/or graphene oxide and etchant, preferably, the quality of described graphene and/or graphene oxide and etchant When the ratio is 0.1-10:1, more preferably 0.5-2:1, porous graphene with adjustable pore size and pore distribution can be obtained.

In the present invention, there is no special requirement on the application form of graphene and/or graphene oxide, for example, graphene and/or graphene oxide can be mixed with etchant in powder form, also can be in the form of dispersion liquid Mixed with etchant, preferably, the graphene and/or graphene oxide is mixed with etchant in the form of a dispersion, so that the graphene and/or graphene oxide is mixed with etchant more effectively Uniform, thereby obtaining porous graphene with tunable pore distribution.

When the graphene and/or graphene oxide is mixed with the etchant in the form of a dispersion, the concentration of the dispersion of the graphene and/or graphene oxide is preferably 0.1-20 mg/mL, more preferably 0.5-4mg/mL. The dispersion of graphene and/or graphene oxide may be formed by dispersing graphene and/or graphene oxide in a dispersion medium. The present invention has no special requirements on the dispersion medium, as long as it can form a dispersion liquid of the graphene and/or graphene oxide, preferably, the dispersion medium is water, methanol, ethanol or N,N- dimethylformamide. The present invention does not have special requirement to the method for forming the dispersion liquid of described graphene and/or graphene oxide, optionally, can also carry out ultrasonic treatment after described graphene and/or graphene oxide is mixed with dispersion medium , a more uniform dispersion of the graphene and/or graphene oxide can be obtained.

In the present invention, the etchant can be mixed with graphene and/or graphene oxide in powder form, or can be mixed with graphene and/or graphene oxide in the form of solution or dispersion liquid, preferably , the etchant is mixed with graphene and/or graphene oxide in the form of solution or dispersion. The concentration of the etchant solution or etchant dispersion is preferably 0.01-10 mol/L, more preferably 0.1-1 mol/L. The formation of the etchant solution or etchant dispersion is determined by the etchant. When the etchant is soluble in the dispersion, the etchant solution is formed, and when the etchant is insoluble in the dispersion, the etchant dispersion is formed.

In the present invention, graphene and/or graphene oxide are mixed with etchant to obtain a mixture, in order to keep the sheet structure of graphene and/or graphene oxide in the mixture, preferably, for graphene and/or Or the mixture formed by mixing the graphene oxide and the etchant is dried using a freeze dryer to obtain a dried product, and then the dried product is subjected to a carbon thermal reaction. The present invention has no special requirements on the freeze-drying conditions, and freeze-drying conditions known to those skilled in the art can be used. Preferably, the freeze-drying conditions include: the temperature is (-80)-(-50)°C, and the time is 6-72h.

In the present invention, graphene and graphene oxide can be directly purchased commercially, or can be prepared according to methods known to those skilled in the art, and there is no special requirement in the present invention. For example, the graphene oxide can be prepared by the Hummers method (Hummers, W.; Offeman, R. Preparation of Graphic Oxide. J. Am. Chem. Soc. 1958, 80 (6), 1339.); Graphene can be reduced by graphene oxide methods (reduction methods include chemical reagent reduction, electrochemical reduction, high temperature thermal reduction, water/solvothermal reduction), chemical vapor deposition, physical exfoliation, ultrasonic dispersion, axial epitaxy Growth and other methods of preparation.

In the present invention, the oxygen-free condition refers to a condition without oxygen, so as to avoid carbon consumption caused by oxidation of carbon to CO and/or CO ₂ in the presence of oxygen. The oxygen-free condition may be a condition in the presence of an inert gas (such as nitrogen and/or argon), or a vacuum condition, which is not particularly required in the present invention.

The acid treatment refers to soaking the carbothermal reaction product with acid to remove unreacted and reacted etchant. The acid can be any acid known to those skilled in the art, such as hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, etc., preferably hydrochloric acid. The amount of the acid used in the present invention is not particularly required, as long as the unreacted and reacted etchant can be completely removed, preferably, the molar ratio of the acid to the initially added etchant is 10-50 :1.

According to the method of the present invention, the present invention has no special requirements on the type of the oxometalate. Preferably, the oxometalate can be sodium molybdate, potassium molybdate, lithium tungstate, sodium tungstate , potassium tungstate, lithium stannate, sodium stannate, potassium stannate, lithium aluminate, sodium aluminate, potassium aluminate, lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, vanadium Potassium bismuthate, lithium bismuthate, sodium bismuthate, potassium bismuthate, lithium permanganate, potassium permanganate, sodium permanganate, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, dichromic acid Sodium, lithium chromate, potassium chromate, sodium chromate, lithium zirconate, sodium zirconate, potassium zirconate, lithium ferrate, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, Lithium Niobate, Sodium Niobate, Potassium Niobate, Lithium Cobaltate, Sodium Cobaltate, Potassium Cobaltate, Lithium Nickelate, Sodium Nickelate, Potassium Nickelate, Silicon Molybdenum Acid, Silicon Tungstic Acid, Silicon Vanadate Acid, Molybdenum Acid One or more of ammonium, ammonium tungstate, ammonium vanadate, ammonium manganate, ammonium dichromate, ammonium chromate, ammonium nickelate, phosphotungstic acid, phosphomolybdic acid and phosphovanadate.

According to the method of the present invention, the present invention has no special requirements on the type of the metal hydroxide, preferably, the metal hydroxide can be the first IIA, IIIA, IB, IIB, IVB, VB, VIB, One or more hydroxides of Group VIII and lanthanide metals. More preferably, the metal hydroxide is one or more metals of magnesium, aluminum, copper, zinc, cadmium, titanium, zirconium, vanadium, niobium, molybdenum, iron, cobalt, nickel, ruthenium and lanthanum hydroxide.

According to the method of the present invention, the present invention has no special requirements on the type of the metal oxide, preferably, the metal oxide is one of the metals of Group IIIA, IB, IIB, IVB, VB and VIII or multiple oxides. More preferably, the metal oxide is an oxide of one or more metals selected from aluminum, copper, zinc, chromium, zirconium, vanadium, iron, cobalt and nickel.

In the present invention, the purpose of preparing porous graphene in the present invention can be achieved even though the aforementioned metal oxo salt, metal hydroxide or metal oxide particles are used as an etchant. However, due to the good water solubility of metal oxoates, metal acid groups can easily assemble on the surface of graphene to form nanostructures (mainly nanoparticles) by utilizing the chemical adsorption between metal acid groups and graphene. Adjust the solution concentration to control the size and shape of the etchant, and further realize the control of the pore structure of the porous graphene surface. Therefore, the present invention preferably uses an oxometalate as an etchant to prepare porous graphene. Further, in consideration of cost, it is particularly preferred in the present invention that the etchant is sodium aluminate, sodium molybdate and sodium tungstate.

According to the method of the present invention, the carbothermal reaction conditions can be any reaction conditions known to those skilled in the art, as long as the carbon thermal reaction of graphene and/or graphene oxide and etchant can occur That is, preferably, the carbothermal reaction conditions include: a temperature of 300-1000° C., preferably 350-650° C., and a time of 5-300 minutes, preferably 30-120 minutes.

A preferred preparation method of porous graphene can be as follows:

(1) Preparation of dispersion liquid of graphene oxide

Add natural flake graphite and sodium nitrate to concentrated sulfuric acid at a temperature of 20-30°C, then cool in an ice-water bath at 0-2°C for 30-120 minutes, after cooling, add potassium manganate at 2-10°C , the ice-water bath was removed and kept for 2-200 hours to obtain a brown mixture. Wherein, the weight ratio of each substance added is natural flake graphite: sodium nitrate: concentrated sulfuric acid: potassium permanganate=1:0.5-1:80-150:3-5.

Add ultrapure water (ultrapure water, also called tertiary water, which is more pure than deionized water, and its conductivity is 18.2MΩcm. In addition, you can also add deionized water, pure water or tap water) to dilute (ultrapure water : natural flake graphite=100-200:1, mass ratio), keep for 20-120min, then add hydrogen peroxide ultrapure aqueous solution (1-10% by mass), until the remaining potassium permanganate and manganese dioxide generated in the reaction All were converted to manganese sulfate, giving a bright yellow suspension. Finally, it was repeatedly washed with ultrapure water until there were no sulfate ions in the suspension. The suspension is separated by centrifugation (2000-6000×g, 5-10min), and the precipitate at the bottom of the centrifuge tube is removed, and the obtained solution is the graphene oxide ultrapure water dispersion.

(2) Preparation of precursor-1: mixture of graphene oxide and sodium molybdate

Mix the graphene oxide ultrapure aqueous solution (0.1-20 mg/mL) obtained in step (1) with sodium molybdate solution (0.01-10 mol/L), shake in a shaker for 6-24 hours at a speed of 50- 200rpm. Freeze the mixed solution in a liquid nitrogen bath for 5-20 minutes, and then dry it with a freeze dryer (12-48 hours, at a temperature of -50° C. and a pressure of 7.5 Pa), to prepare a mixture of graphene and sodium molybdate.

(3) Preparation of intermediate-1: graphene-molybdenum oxide hybrid material

Use the mixture of graphene oxide and sodium molybdate obtained in step (2) as a precursor, place it in a tube furnace, and raise the temperature to 300-1000°C under nitrogen protection, with a heating rate of 5-20 ℃/min, keep warm for 5-300 minutes, and cool down to room temperature naturally.

(4) Preparation of porous graphene

The obtained Intermediate-1 was dispersed in dilute hydrochloric acid (0.1-1mol/L, 50mL), stirred for 1-7 days, collected by filtration, washed three times with ultrapure water, washed once with ethanol, and dried at 60-120°C for 6- After 24 hours, the obtained black solid powder is the porous graphene sample.

On the other hand, the present invention also provides a method for preparing a porous graphene film, wherein, the method includes, dispersing an etchant on the graphene and/or graphene oxide film, and performing carbonization under an oxygen-free condition. heat reaction, and acid treatment to remove unreacted and reacted etchant; the etchant is one or more of metal oxo salt, metal hydroxide and metal oxide.

According to the method of the present invention, as long as the etchant is dispersed on the graphene and/or graphene oxide film, carbon thermal reaction or electron beam etching is carried out under oxygen-free conditions and acid treatment is carried out to remove unreacted Or the porous graphene film can be obtained after the reaction, the present invention has no special requirements on the consumption of graphene and/or graphene oxide and etchant, preferably, the graphene and/or graphene oxide and etchant When the mass ratio of the etchant is 0.1-10:1, more preferably 0.5-2:1, porous graphene with more uniform pore size and pore distribution can be obtained.

In the present invention, the graphene and/or graphene oxide film can be obtained by depositing a graphene and/or graphene oxide film on a substrate with a graphene and/or graphene oxide dispersion. The present invention does not require the substrate, for example, silicon, glass, quartz and metal (copper, nickel, iron) substrates may be used. The thickness of the graphene and/or graphene oxide film is not required in the present invention, and can be selected according to actual needs. Preferably, the thickness of the graphene and/or graphene oxide film is 5-50 nm.

In the present invention, there is no special requirement on the application form of graphene and/or graphene oxide. Graphene and/or graphene oxide can be mixed with etchant in the form of powder, or mixed with etchant in the form of dispersion liquid. etchant, preferably, the graphene and/or graphene oxide is mixed with the etchant in the form of a dispersion, so that the graphene and/or graphene oxide is mixed with the etchant more uniformly, Porous graphene with more uniform pore distribution is thus obtained.

When the graphene and/or graphene oxide is mixed with the etchant in the form of a dispersion, the concentration of the dispersion of the graphene and/or graphene oxide is preferably 0.1-20 mg/mL, more preferably 0.5-4mg/mL. The dispersion of graphene and/or graphene oxide may be formed by dispersing graphene and/or graphene oxide in a dispersion medium. The dispersion medium is not particularly required in the present invention, as long as it can form a dispersion liquid of the graphene and/or graphene oxide, preferably, the dispersion medium can be water, methanol, ethanol or N,N- dimethylformamide. The method for forming the dispersion liquid of the graphene and/or graphene oxide is not particularly required in the present invention. Preferably, the graphene and/or graphene oxide is mixed with a dispersion medium and subjected to ultrasonic treatment to obtain A relatively uniform dispersion of the graphene and/or graphene oxide.

In the present invention, the etchant can be dispersed on the graphene and/or graphene oxide film in the form of powder, or can be dispersed on the graphene and/or graphene oxide film in the form of solution or dispersion , preferably, the etchant is dispersed on the graphene and/or graphene oxide film in the form of a solution or a dispersion, and finally the etchant is uniformly dispersed on the graphene and/or graphene oxide film . The concentration of the etchant solution or etchant dispersion is preferably 0.01-10 mol/L, more preferably 0.1-1 mol/L. The formation of the etchant solution or etchant dispersion is determined by the etchant. When the etchant is soluble in the dispersion, the etchant solution is formed, and when the etchant is insoluble in the dispersion, the etchant dispersion is formed.

In the present invention, the etchant is dispersed on the graphene and/or graphene oxide film to obtain a mixture, in order to keep the sheet structure of the graphene and/or graphene oxide film in the mixture, preferably, for all The mixture was freeze-dried. The freeze-drying conditions are not particularly required in the present invention, and freeze-drying conditions known to those skilled in the art can be used. Preferably, the freeze-drying conditions include: the temperature is (-80)-(-50)°C, and the time is 6-72h.

According to the method of the present invention, the carbothermal reaction conditions can be any reaction conditions known to those skilled in the art, as long as the carbon thermal reaction of graphene and/or graphene oxide and etchant can occur That is, preferably, the carbothermal reaction conditions include: a temperature of 300-1000° C., preferably 350-650° C., and a time of 5-300 minutes, preferably 30-120 minutes.

In the present invention, in the preparation method of the porous graphene film, the method of heating can be used to obtain the above treatment temperature. In addition, the present invention can also use the method of electron beam etching to provide energy so that the reaction system reaches the conditions of carbon thermal reaction . The electron beams can be thermal emission electrons, field emission electrons and Schottky emission electrons, which can be obtained by generating high-energy electron beams through the high voltage between the cathode and anode filaments in the electron gun. The conditions of the electron beam etching preferably include: the etching voltage is 1-20KV, preferably 6-10KV, the time is 0.5-10 minutes, and the time is 3-5 minutes.

In the present invention, the oxygen-free condition refers to a condition without oxygen, so as to prevent carbon from being oxidized to CO and/or CO ₂ in the presence of oxygen to cause carbon consumption. The oxygen-free condition may be a condition in the presence of an inert gas (such as nitrogen and/or argon) or a vacuum condition, which is not particularly required in the present invention.

The acid treatment refers to soaking the carbothermal reaction product with acid to remove unreacted or reacted etchant. The acid can be any acid known to those skilled in the art, such as hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, etc., preferably hydrochloric acid. The amount of the acid used in the present invention is not particularly required, as long as the unreacted or reacted etchant in the product of the carbothermal reaction can be completely removed, preferably, the acid is mixed with the initially added etching agent. The molar ratio of the agent is 10-50:1.

In the present invention, graphene, graphene oxide, metal oxo salt, metal hydroxide and metal oxide may be as described above, and will not be repeated here.

According to the method of the present invention, the carbothermal reaction conditions can be any reaction conditions known to those skilled in the art, as long as the carbon thermal reaction of graphene and/or graphene oxide and etchant can occur That is, preferably, the carbothermal reaction conditions include: a temperature of 300-1000° C., preferably 350-650° C., and a time of 5-300 minutes, preferably 30-120 minutes.

The present invention will be described in detail below by way of examples.

Preliminary Example 1 prepares the ultrapure aqueous solution of graphene oxide

At 20°C, add 2.0g of flake graphite with a fineness of 325 mesh and 1.5g of sodium nitrate to 80mL of concentrated sulfuric acid (98% by weight), place the resulting mixture in a 500mL beaker and cool it with an ice-water bath at 0°C After 30 minutes, until the temperature reached 8°C, a suspension was obtained.

At 5°C, at a stirring speed of 700rpm (the size of the stirring bar: 6cm), add 9.0g of potassium permanganate to the above suspension (adding once every 15 minutes, adding 1.5g each time), and then Remove the ice-water bath and keep it for 120 hours, then add 150mL of ultrapure water (50mL every 5 minutes), and half an hour later, add 250mL of 3% by mass hydrogen peroxide to obtain a bright yellow solution. Centrifuge and wash with ultrapure water until there is no sulfate ion in the bright yellow solution, then centrifuge the solution (2560×g, 3000rpm) to obtain a 6 mg/mL graphene oxide ultrapure aqueous solution, and then add ultrapure water Diluted to obtain a 4 mg/mL ultrapure aqueous solution of graphene oxide, the ratio of the number of carbon atoms of the graphene oxide to the number of oxygen atoms is C/O=2.

Preparatory embodiment 2 prepares graphene

Preliminary Example 2.1

Graphene prepared by hydrothermal method

Dilute the graphene oxide ultrapure aqueous solution obtained in Preliminary Example 1 to 2 mg/mL, take 30 mL, ultrasonicate for 30 minutes (power 80 W), put it into a 50 mL autoclave, and heat at 180 ° C for 6 hours to obtain a black solid , collected by filtration, washed once with ultrapure water, frozen in a liquid nitrogen bath for 15 minutes, and then dried using a freeze dryer (48 hours, at a temperature of -50°C and a pressure of 7.5Pa). Finally, 42mg of graphene black solid was obtained.

Preliminary Example 2.2

Preparation of Graphene by High Temperature Thermal Reduction Method

The graphene oxide ultrapure aqueous solution obtained in Preliminary Example 1 was frozen in a liquid nitrogen bath for 15 minutes, and then dried using a freeze dryer (48 hours, at a temperature of -50° C. and a pressure of 7.5 Pa). The obtained graphene oxide (100mg) was placed in a tube furnace, under the condition of nitrogen protection, the temperature was raised to 650°C, the heating rate was 10°C/min, kept for 120 minutes, and naturally cooled to room temperature. Finally, 69mg of graphene black solid was obtained.

Preliminary Example 2.3

Preparation of graphene by reduction of hydrazine hydrate

Dilute the ultrapure aqueous solution of graphene oxide obtained in Preliminary Example 1 to 2 mg/mL, take 30 mL, ultrasonicate for 30 minutes (power 80 W), add 0.5 mL of hydrazine hydrate solution (85% by mass), and stir for 12 hours at a temperature of 40 °C . It was collected by filtration, washed three times with ultrapure water, washed once with ethanol, and dried at 60° C. for 12 hours to finally obtain 40 mg of graphene black solid. .

Preliminary Example 3 Preparation of Metal Hydroxide Nanoparticles

Preliminary Example 3.1

Preparation of cerium hydroxide nanoparticle suspension

Add the ultrapure aqueous solution of sodium hydroxide (25mol/L) dropwise to the ultrapure aqueous solution of cerium nitrate (1mol/L, 50mL), adjust the pH of the solution to 10, and stir for 30 minutes to obtain 1mol/L white cerium hydroxide nanoparticle suspension.

Preliminary Example 3.2-3.21

According to the method for preparing metal hydroxide in preliminary example 3.1, the difference is that the metal salt used is changed from cerium nitrate to ferrous sulfate, ferrous chloride, ferric sulfate, aluminum chloride, zinc chloride, ruthenium chloride, Magnesium chloride, molybdenum trichloride, molybdenum dichloride, zirconium chloride, copper sulfate, copper chloride, titanium tetrachloride, nickel chloride, nickel chloride, cadmium chloride, lanthanum chloride, cobalt chloride, chloride Vanadium and niobium chloride were used to prepare the corresponding hydroxide nanoparticle suspensions.

Preliminary Example 3.22-3.25

Cerium hydroxide nanoparticles were prepared according to the method of Preliminary Example 3.1, except that the concentration of cerium nitrate ultrapure aqueous solution was 0.01 mol/L, 0.1 mol/L, 0.5 mol/L and 10 mol/L.

Preliminary Example 4 Prepares Metal Oxide Nanoparticles

Preliminary Example 4.1

Preparation of Ferric Oxide Nanoparticles

Dissolve iron acetylacetonate in N,N-dimethylformamide (DMF), the solution concentration is 0.5mol/L, after stirring for 4 hours, take 30mL into a high-pressure reactor with a volume of 50mL, and heat at 200°C for 24 hours , to obtain a black solid, which was collected by filtration, washed once with ultrapure water, washed three times with ethanol, and dried at 60° C. for 12 hours to obtain ferric oxide nanoparticles.

Preliminary Example 4.2-4.9

Metal oxide nanoparticles were prepared according to the method in Example 4.1, except that the metal precursors used in step (1) were different, that is, the metal complexes were aluminum acetylacetonate, vanadium acetylacetonate, nickel acetylacetonate, zirconium acetylacetonate, acetylacetonate Cobalt acetonate, zinc acetylacetonate, copper acetylacetonate, chromium acetylacetonate. The corresponding metal oxide nanoparticles were obtained.

Preliminary Example 4.10-4.12

Ferric oxide nanoparticles were prepared according to the method of Preliminary Example 4.1, except that the concentrations of the DMF solutions of iron acetylacetonate were 0.1 mol/L, 1 mol/L and 10 mol/L, respectively.

Preliminary Example 5 Prepares Graphene Oxide Film and Graphene Film

Preliminary Example 5.1

Fabrication of Graphene Oxide Thin Films by Spin Coating

The graphene oxide thin film is prepared by spin-coating method, using a silicon wafer or a glass wafer as the substrate (specification: 1cm×1cm). The substrate was soaked in a mixed solution of concentrated sulfuric acid (98 wt.) and hydrogen peroxide (30 wt.) (concentrated sulfuric acid: hydrogen peroxide = 7:3, volume ratio), reacted at 70°C for 30 minutes, cooled naturally to room temperature, and rinsed with ultrapure water rinse. The graphene oxide prepared in Preliminary Example 1 was prepared into a mixed solution of water and ethanol with a concentration of 1.5 mg/mL (the volume ratio of water and ethanol was 1:3), and 30 mL was taken and ultrasonicated for 30 minutes (power 80W). Drop 0.5mL graphene oxide solution on the substrate, start the spin coater (uniform coating speed is 100rpm, 15s; spin coating speed is 3000rpm, 60s), and the spin coating step is repeated 3 times. The prepared graphene oxide film was dried in an oven at a temperature of 60°C.

Preliminary Example 5.2

Preparation of Graphene Thin Films by Thermal Reduction at High Temperature

Put the graphene oxide film prepared in Preliminary Example 5.1 in a tube furnace, and raise the temperature to 400°C under nitrogen protection at a heating rate of 10°C/min, keep it warm for 30 minutes, and cool down to room temperature naturally. A black graphene film is obtained.

Preliminary Example 5.3

Preparation of Graphene Films by Hydrothermal Reduction

Suspend the graphene oxide film prepared in Preliminary Example 5.1 in a reaction kettle (volume 50mL), add 15mL of ultrapure water into the reaction kettle (the graphene oxide film is not soaked in ultrapure water), and put the reaction kettle Place in an oven and heat at 180°C for 6 hours. A black graphene film is obtained.

Preliminary Example 5.4

Preparation of graphene thin films by vapor reduction of hydrazine hydrate

The graphene oxide film prepared in Preliminary Example 5.1 was placed in hydrazine hydrate vapor (saturated vapor pressure), and reacted for 6 hours at a temperature of 40°C. A black graphene film is obtained.

Preliminary Example 5.5

Graphene film prepared by physical exfoliation method

Using highly oriented pyrolysis graphite as raw material, single-layer graphene was prepared by tearing graphite with tape, and transferred to a silicon substrate (1cm×1cm).

Preliminary Example 5.6

Graphene film prepared by chemical vapor deposition

Use copper foil or nickel foil as the substrate, use methane or acetylene (high-purity gas) as the carbon source, the growth temperature is 1000°C, the carrier gas is a mixture of hydrogen and argon (1:99), and the cooling rate is 10°C/ minute.

(1) Preparation of porous graphene

Example 1 Preparation of Porous Graphene Using Oxometalate as an Etchant (Route 1)

Example 1.1

(1) Preparation of a mixture of graphene oxide and sodium molybdate

The graphene oxide ultrapure aqueous solution (4 mg/mL, 50 mL) obtained in Preliminary Example 1 was mixed with the sodium molybdate ultrapure aqueous solution (0.02 mol/L, 50 mL). Shake in a shaker for 12 hours at 100 rpm. After the mixed solution was frozen in a liquid nitrogen bath for 15 minutes, it was dried using a freeze dryer (48 hours, the temperature was -50°C, and the pressure was 7.5Pa), and a mixture of graphene oxide and sodium molybdate was prepared.

(2) Preparation of porous graphene

Put the mixture of graphene oxide and sodium molybdate obtained in step (1) as a precursor (200mg) in a tube furnace, and raise the temperature to 650°C under nitrogen protection at a heating rate of 10°C/min. Keep warm for 120 minutes and cool down to room temperature naturally. The obtained black solid was dispersed in dilute hydrochloric acid (0.5mol/L, 50mL), stirred for 3 days, collected by filtration, washed three times with ultrapure water, washed once with ethanol, and dried at 60°C for 12 hours. The obtained black solid powder was It is a porous graphene sample, and the sample mass is about 45mg. The TEM (Tecnai G ² 20S-TWIN transmission electron microscope, FEI Company, USA) of the obtained porous graphene sample is shown in Figure 1.

Example 1.2-1.5

Porous graphene samples were prepared according to the method of Example 1.1, except that the concentration of sodium molybdate ultrapure aqueous solution used in step (1) was 0.01mol/L, 0.1mol/L, 1mol/L and 10mol/L. 50 mg, 49, 46 and 43 mg of black solids were obtained.

Example 1.6-1.8

Porous graphene samples were prepared according to the method of Example 1.1, except that the temperatures used in the high temperature treatment step (2) were 300°C, 350°C, and 1000°C, respectively, and the obtained black solids were 54mg, 54mg, and 34mg respectively.

Example 1.9-1.11

Porous graphene samples were prepared according to the method of Example 1.1, except that the time of high temperature treatment in step (2) was 5 minutes, 60 minutes and 300 minutes respectively, and the obtained black solids were 53mg, 40mg and 34mg respectively.

Example 1.12-1.16

Porous graphene samples were prepared according to the method of Example 1.1, except that the concentrations of graphene oxide ultrapure aqueous solutions used in step (1) were 0.5mg/mL, 2mg/mL, 8mg/mL, 10mg/mL and 20mg /mL. Black solids were obtained as 52mg, 53mg, 53mg, 52mg and 54mg respectively.

Example 1.17-1.77

Prepare porous graphene samples according to the method in Example 1.1, the difference is that the metal oxolate used in step (1) is potassium molybdate, lithium tungstate, sodium tungstate, potassium tungstate, lithium stannate, stannic acid Sodium, potassium stannate, lithium aluminate, sodium aluminate, potassium aluminate, lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, potassium vanadate, lithium bismuthate, sodium bismuthate, Potassium bismuthate, lithium permanganate, potassium permanganate, sodium permanganate, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, sodium dichromate, lithium chromate, potassium chromate, chromium Sodium zirconate, lithium zirconate, sodium zirconate, potassium zirconate, lithium ferrate, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, lithium niobate, sodium niobate, potassium niobate , Lithium cobaltate, sodium cobaltate, potassium cobaltate, lithium nickelate, sodium nickelate, potassium nickelate, silicomomolybdic acid, silicotungstic acid, silicovanadate, ammonium molybdate, ammonium tungstate, ammonium vanadate, manganese ammonium dichromate, ammonium chromate, ammonium nickelate, phosphotungstic acid, phosphomolybdenum and phosphovanadate. The black solid mass obtained is about 51, 53, 46, 47, 53, 47, 46, 45, 49, 47, 49, 53, 55, 53, 49, 50, 51, 47, 54, 54, 51, 53 , 49, 46, 47, 51, 51, 47, 53, 47, 54, 46, 46, 53, 53, 49, 46, 47, 50, 51, 47, 53, 51, 49, 54, 46, 51 , 53, 46, 47, 50, 51, 47, 51, 47, 50, 51, 47, 53, 51 and 53 mg.

Example 1.77

The porous graphene sample was prepared according to the method of Example 1.1, except that in step (2), the nitrogen protection condition was changed to vacuum condition (less than 10Pa).

Example 2 Preparation of porous graphene using oxometalate as etchant (Route 2)

Example 2.1

(1) Preparation of a mixture of graphene and sodium molybdate

The porous graphene sample was prepared according to the method of Example 1, except that the graphene (200 mg) obtained in Preliminary Example 2.1 was used in this example. The obtained black solid powder has a mass of 56 mg.

Example 2.2-2.3

Prepare porous graphene samples according to the method of Example 2.1, the difference is that the graphene used in step (1) is the graphene prepared in Preliminary Example 2.2 and 2.3 respectively, and the quality of the black solid obtained is 55 mg and 57 mg respectively .

Example 2.4-2.6

Prepare porous graphene sample according to the method of embodiment 2.1, difference is, the concentration of the sodium molybdate ultrapure aqueous solution that step (1) uses is respectively 0.01mol/L, 0.5mol/L and 10mol/L, obtains the black solid The masses are 60mg, 48mg and 34mg respectively.

Example 2.7-2.9

Porous graphene samples were prepared according to the method of Example 2.1, except that the temperatures used in the high temperature treatment step (2) were 450°C, 300°C, and 1000°C, respectively, and the obtained black solids were 56mg, 55mg, and 37mg respectively. Among them, the TEM of the porous graphene sample prepared at 450°C (Tecnai G ² 20S-TWIN transmission electron microscope, American FEI Company), among which, the porous graphene prepared at 450°C is shown in Figure 2.

Example 2.10-2.12

Porous graphene samples were prepared according to the method of Example 2.1, except that the time of high temperature treatment in step (2) was 5 minutes, 60 minutes and 300 minutes respectively, and the obtained black solids were 56mg, 52mg and 37mg respectively.

Example 2.13-2.73

Porous graphene samples were prepared according to the method in Example 2.1. The difference is that the metal oxolates used in step (1) were potassium molybdate, lithium tungstate, sodium tungstate, potassium tungstate, lithium stannate, and stannic acid. Sodium, potassium stannate, lithium aluminate, sodium aluminate, potassium aluminate, lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, potassium vanadate, lithium bismuthate, sodium bismuthate, Potassium bismuthate, lithium permanganate, potassium permanganate, sodium permanganate, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, sodium dichromate, lithium chromate, potassium chromate, chromium Sodium zirconate, lithium zirconate, sodium zirconate, potassium zirconate, lithium ferrate, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, lithium niobate, sodium niobate, potassium niobate , Lithium cobaltate, sodium cobaltate, potassium cobaltate, lithium nickelate, sodium nickelate, potassium nickelate, silicomomolybdic acid, silicotungstic acid, silicovanadate, ammonium molybdate, ammonium tungstate, ammonium vanadate, manganese ammonium dichromate, ammonium chromate, ammonium nickelate, phosphotungstic acid, phosphomolybdic acid and phosphovanadate. The mass of the obtained black solid was about 48-60 mg.

Example 2.74

The porous graphene sample was prepared according to the method of Example 2.1, except that in step (2), the nitrogen protection condition was changed to vacuum condition (less than 10Pa).

Example 3 Preparation of Porous Graphene Using Metal Hydroxide as an Etchant (Route 1)

Example 3.1

(1) Preparation of a mixture of graphene oxide and cerium hydroxide

Add the cerium hydroxide suspension (0.1mol/L, 50mL) obtained in Preliminary Example 3.1 dropwise into the ultrapure aqueous solution of graphene oxide (4mg/mL, 50mL), ultrasonicate for 30 minutes (power 80W), and stir for 12 Hour. The obtained homogeneous mixture solution was frozen in a liquid nitrogen bath for 15 minutes, and then dried using a freeze dryer (48 hours, temperature: -50° C., pressure: 7.5 Pa).

(2) Preparation of porous graphene

The mixture of graphene and cerium hydroxide obtained in step (1) was used as a precursor (200mg), and it was placed in a tube furnace. Under the condition of nitrogen protection, the temperature was raised to 650°C, and the heating rate was 10°C/min , keep warm for 120 minutes, and cool down to room temperature naturally.

The obtained black solid was dispersed in dilute hydrochloric acid (0.5mol/L, 50mL), stirred for 3 days, collected by filtration, washed three times with ultrapure water, washed once with ethanol, and dried at 60°C for 12 hours. The mass of the obtained black solid was 52 mg. The SEM (Hitachi S-4800 scanning electron microscope, Hitachi, Japan) photo of the prepared porous graphene sample is shown in Figure 3.

Example 3.2-3.5

Prepare porous graphene samples according to the method of Example 3.1, the difference is that the temperatures used in step (2) high-temperature treatment step are 900°C, 450°C, 300°C and 1000°C respectively, and the obtained black solids are 35mg, 52mg, 54mg respectively and 33mg.

Example 3.6-3.9

Prepare porous graphene samples according to the method of Example 3.1, the difference is that the time of step (2) high temperature treatment is 5 minutes, 60 minutes, 200 minutes and 300 minutes respectively, and the obtained black solids are 52mg, 49mg, 38mg and 33mg respectively .

Example 3.10-3.14

Porous graphene samples were prepared according to the method of Example 3.1, except that the concentrations of the graphene oxide ultrapure aqueous solutions used in step (1) were 2mg/mL, 6mg/mL, 8mg/mL, 10mg/mL and 20mg /mL. Black solids were obtained as 35mg, 62mg, 78mg, 89mg and 118mg respectively.

Example 3.15-3.38

Porous graphene samples were prepared according to the method in Example 3.1, except that the metal hydroxides used in step (1) were different, which were the metal hydroxide nanoparticle suspensions prepared in Preliminary Examples 3.2-3.25. The obtained black solid masses were 45, 47, 46, 45, 49, 47, 49, 53, 55, 49, 50, 51, 47, 54, 46, 51, 53, 49, 46, 47, 50, 51 , 47 and 53 mg.

Example 3.39

The porous graphene sample was prepared according to the method of Example 3.1, except that in step (2), the nitrogen protection condition was changed to vacuum condition (less than 10Pa).

Example 4 Preparation of Porous Graphene Using Metal Oxide as an Etchant (Route 1)

Example 4.1

(1) Preparation of graphene modified with Fe3O4 nanoparticles

Adjust the concentration of the graphene oxide ultrapure aqueous solution obtained in Preliminary Example 1 to 8 mg/mL, dissolve iron acetylacetonate in N,N-dimethylformamide (DMF), and the solution concentration is 0.1 mol/L, The two solutions were mixed in a volume ratio of 1:1 (50 mL each). After stirring for 4 hours, take 30 mL into a 50 mL autoclave and heat at 200°C for 24 hours to obtain a black solid, which is collected by filtration, washed once with ultrapure water and three times with ethanol, and dried at 60°C for 12 hours.

(2) Preparation of porous graphene

The graphene modified with ferric oxide nanoparticles obtained in step (1) was used as a precursor (200mg), and placed in a tube furnace, under the condition of nitrogen protection, the temperature was raised to 650°C, and the heating rate was 10°C /min, keep warm for 120 minutes, and cool down to room temperature naturally.

The obtained black solid was dispersed in dilute hydrochloric acid (0.5mol/L, 50mL), stirred for 3 days, collected by filtration, washed three times with ultrapure water, washed once with ethanol, and dried at 60°C for 12 hours. The obtained black solid powder was for porous graphene samples.

Example 4.2-4.4

Porous graphene samples were prepared according to the method in Example 4.1, except that the concentrations of the DMF solutions of iron acetylacetonate in step (1) were 0.5 mol/L, 1 mol/L and 10 mol/L, respectively. Black solids were obtained as 63mg, 54mg and 44mg respectively.

Example 4.5-4.7

Porous graphene samples were prepared according to the method of Example 4.1, except that the temperatures used in the high temperature treatment step (2) were 300°C, 450°C, and 1000°C, respectively, and the obtained black solids were 54mg, 52mg, and 33mg respectively.

Example 4.8-4.10

Porous graphene samples were prepared according to the method of Example 4.1, except that the high temperature treatment time in step (2) was 5 minutes, 60 minutes and 300 minutes respectively, and black solids of 52 mg, 49 mg and 33 mg were obtained, respectively.

Example 4.11-4.14

Porous graphene samples were prepared according to the method of Example 4.1, except that the concentrations of the graphene oxide ultrapure aqueous solutions used in step (1) were 4 mg/mL, 10 mg/mL, 16 mg/mL and 20 mg/mL. 38mg, 45mg, 58mg and 98mg of black solids were obtained respectively.

Example 4.15-4.22

Prepare porous graphene samples according to the method of Example 4.1, the difference is that the metal precursors used in step (1) are different, that is, the metal complexes are aluminum acetylacetonate, vanadium acetylacetonate, nickel acetylacetonate, zirconium acetylacetonate, acetylacetonate Cobalt acetonate, zinc acetylacetonate, copper acetylacetonate, chromium acetylacetonate. The mass of the obtained black solid was about 45-55 mg.

Example 4.23

The porous graphene sample was prepared according to the method of Example 4.1, except that in step (2), the nitrogen protection condition was changed to vacuum condition (less than 10Pa).

Example 5 Preparation of Porous Graphene Using Metal Oxide as an Etchant (Route 2)

Example 5.1

(1) Preparation of a mixture of graphene oxide and ferric oxide

Disperse the iron ferric oxide nanoparticles (100mg) obtained in Preliminary Example 4.1 in ultrapure water (25mL), and after ultrasonication for 30 minutes (power 80W), add it to the ultrapure aqueous solution of graphene oxide (4mg/mL, 25mL), the mass ratio of graphene oxide to ferric oxide nanoparticles was 1:1, sonicated for 1 hour (power 80W), and then stirred for 12 hours. The obtained homogeneous mixture solution was frozen in a liquid nitrogen bath for 15 minutes, and then dried using a freeze dryer (48 hours, temperature: -50° C., pressure: 7.5 Pa).

(2) Preparation of porous graphene

The graphene modified with ferric oxide nanoparticles obtained in step (1) was used as a precursor (200mg), and placed in a tube furnace, under the condition of nitrogen protection, the temperature was raised to 650°C, and the heating rate was 10°C /min, keep warm for 120 minutes, and cool down to room temperature naturally.

The obtained black solid was dispersed in dilute hydrochloric acid (0.5mol/L, 50mL), stirred for 3 days, collected by filtration, washed three times with ultrapure water, washed once with ethanol, and dried at 60°C for 12 hours. The obtained black solid powder The mass is 56mg.

Example 5.2-5.4

Porous graphene samples were prepared according to the method of Example 5.1, except that the temperatures used in the high temperature treatment step (2) were 300°C, 450°C, and 1000°C, respectively, and the obtained black solids were 58mg, 54mg, and 35mg respectively.

Example 5.5-5.7

Porous graphene samples were prepared according to the method of Example 5.1, except that the time of high temperature treatment in step (2) was 5 minutes, 60 minutes and 300 minutes, respectively, and the obtained black solids were 56 mg, 52 mg and 36 mg, respectively.

Example 5.8-5.11

Porous graphene samples were prepared according to the method in Example 5.1, except that the concentrations of the graphene oxide ultrapure aqueous solutions used in step (2) were 2 mg/mL, 8 mg/mL, 16 mg/mL and 20 mg/mL. Black solids were obtained as 36mg, 76mg, 98mg and 112mg respectively.

Example 5.12-5.22

Porous graphene samples were prepared according to the method in Example 5.1, except that the metal oxide nanoparticles were different, that is, the metal oxides prepared in Preliminary Examples 4.2-4.12. The mass of the obtained black solid was 45-55 mg.

Example 5.23

The porous graphene sample was prepared according to the method of Example 5.1, except that in step (2), the nitrogen protection condition was changed to vacuum condition (less than 10Pa).

Comparative example 1 electron beam radiation method prepares porous graphene

Graphene was prepared by chemical vapor deposition and transferred onto a copper grid (references for this step: Li, X.; Cai, W.; An, J.; Kim, S.; Nah, J.; Yang, D.; Piner, R.; Velamakanni, A.; Jung, I.; Tutuc, E.; Banerjee, SK; Colombo, L.; Ruoff, RS Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils. , 324, 1312-1314.). Palladium nanoparticles were deposited on the graphene surface by electron beam evaporation. Transfer the copper grid into the electron microscope sample compartment (UltraSTEM100 aberration-corrected scanning transmission electron microscope), and irradiate graphene (60keV) with electron beams under vacuum conditions (5×10 ^-9 Torr), and a defect structure appears on the graphene surface, namely Porous graphene samples were prepared (Zan, R.; Ramasse, QM; Bangert, U.; Novoselov, KS Graphene Reknits Its Holes. Nano Lett. 2012, 12(8), 3936-3940.). This method is to operate and process on a single sheet of graphene, and the yield of the prepared porous graphene is extremely low, which is calculated as a "sheet".

Comparative Example 2 Preparation of Porous Graphene by Helium Ion Bombardment

Graphene was prepared by a mechanical exfoliation method and transferred onto a _SiO2 substrate (references for this step: Novoselov, K.; Geim, A.; Morozov, S.; Jiang, D.; Zhang, Y.; Dubonos, S.; Grigorieva, I.; Firsov, A. Electric Field Effect in Atomically Thin Carbon Films. Science 2004, 306, 666-669.). The graphene sample was placed in the sample compartment of a helium ion microscope (Zeiss ORION system), and the sample compartment was cleaned with air plasma before testing (Evactron plasma cleaner, 12W, 10 hours (15 minutes of work, 45 minutes of rest, 10 cycles) ). Use helium ions to bombard graphene with a voltage of 30kV to prepare porous graphene (Bell, DC; Lemme, MC; Stern, LA; Williams, JR; Marcus, CM Precision Cutting and Patterning of Graphene with Helium Ions.Nanotechnology2009, 20(45), 455301.). This method is to operate and process on a single sheet of graphene, and the yield of the prepared porous graphene is extremely low, which is calculated as a "sheet".

(2) Preparation of porous graphene film

Embodiment 6 carbothermal reaction prepares porous graphene film

Example 6.1

An ultrapure aqueous solution of ammonium molybdate (1 mol/mL, 0.1 mL) was covered on the graphene film obtained in Preliminary Example 5.2, and left to dry at 40°C. The thin film sample was placed in a tube furnace, heated to 400°C under the protection of nitrogen, at a heating rate of 10°C/min, kept for 30 minutes, and then naturally cooled to room temperature. The obtained black film was soaked in dilute hydrochloric acid (0.5mol/L, 20mL), washed three times with ultrapure water and once with ethanol, and dried at 60°C for 12 hours. The result is a porous graphene film. The photos are shown in Figure 4.

Example 6.2-6.5

Porous graphene film samples were prepared according to the method in Example 6.1, except that the concentrations of the ultrapure aqueous solutions of ammonium molybdate were 0.01mol/L, 2mol/L, 5mol/L and 10mol/L, respectively.

Example 6.6-6.10

Porous graphene film samples were prepared according to the method of Example 6.1, except that the temperatures of the high temperature treatment step were 300°C, 350°C, 500°C, 650°C and 1000°C, respectively.

Example 6.11-6.15

Porous graphene film samples were prepared according to the method of Example 6.1, except that the time of the high temperature treatment step was 5 minutes, 30 minutes, 60 minutes, 120 minutes and 300 minutes respectively.

Example 6.16-6.76

Porous graphene samples were prepared according to the method in Example 6.1, except that the oxometalates used were potassium molybdate, lithium tungstate, sodium tungstate, potassium tungstate, lithium stannate, sodium stannate, stannic acid Potassium, lithium aluminate, sodium aluminate, potassium aluminate, lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, potassium vanadate, lithium bismuthate, sodium bismuthate, potassium bismuthate, Lithium permanganate, potassium permanganate, sodium permanganate, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, sodium dichromate, lithium chromate, potassium chromate, sodium chromate, zirconium Lithium oxide, sodium zirconate, potassium zirconate, lithium ferrate, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, lithium niobate, sodium niobate, potassium niobate, lithium cobaltate , Sodium cobaltate, Potassium cobaltate, Lithium nickelate, Sodium nickelate, Potassium nickelate, Silicon molybdenum acid, Silicon tungstic acid, Silicon vanadium acid, Ammonium molybdate, Ammonium tungstate, Ammonium vanadate, Ammonium manganate, Heavy Ammonium chromate, ammonium chromate, ammonium nickelate, phosphotungstic acid, phosphomolybdic acid, and phosphovanadic acid.

Example 6.77-80

Porous graphene film samples were prepared according to the method in Example 6.1, except that the graphene film samples used were the graphene film samples prepared in Preliminary Examples 5.3-5.6.

Example 6.81-106

Porous graphene film samples are prepared according to the method of Example 6.1, the difference is that the etchant used is changed from ammonium molybdate to the cerium hydroxide suspension prepared by preliminary examples 3.1-3.26, and the concentration of the suspension is Dilute to 0.1mol/L.

Example 6.107-114

Porous graphene film samples were prepared according to the method of Example 6.1, except that the etchant used was changed from ammonium molybdate to iron ferric oxide nanoparticles prepared in Preliminary Examples 4.1-4.8. The concentrations of the ultrapure aqueous solution of ferric oxide nanoparticles are all 0.1mol/L.

Example 6.115

Porous graphene samples were prepared according to the method in Example 6.1, except that the nitrogen protection conditions were changed to vacuum conditions (less than 10Pa).

Example 7 Preparation of Porous Graphene Film by Electron Beam Assisted Method

Example 7.1

An ultrapure aqueous solution of ammonium molybdate (1 mol/mL, 0.1 mL) was covered on the graphene film obtained in Preliminary Example 5.2, and left to dry at 40°C. The thin film samples were placed in a vacuum condition and irradiated with an electron beam (electron beam voltage 6KV,) for 5 minutes. The obtained black film was soaked in dilute hydrochloric acid (0.5mol/L, 20mL), washed three times with ultrapure water and once with ethanol, and dried at 60°C for 12 hours. The result is a porous graphene film. The SEM (Hitachi S-4800 scanning electron microscope, Hitachi, Japan) photo of the prepared porous graphene film sample is shown in Figure 5.

Example 7.2-7.5

Porous graphene film samples were prepared according to the method in Example 7.1, except that the concentration of the ultrapure aqueous solution of ammonium molybdate was 0.01mol/L, 2mol/L, 5mol/L and 10mol/L, respectively.

Example 7.6-7.9

Porous graphene film samples were prepared according to the method in Example 7.1, except that the electron beam voltages were 1KV, 10KV, 15KV and 20KV, respectively.

Example 7.10-7.12

Porous graphene film samples were prepared according to the method in Example 7.1, except that the electron beam irradiation time was 0.5 minutes, 3 minutes and 10 minutes respectively.

Example 7.13-1.73

Porous graphene samples were prepared according to the method of Example 7.1, the difference being that the oxometalates used were sodium molybdate, potassium molybdate, lithium tungstate, sodium tungstate, potassium tungstate, lithium stannate, stannic acid Sodium, potassium stannate, lithium aluminate, sodium aluminate, potassium aluminate, lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, potassium vanadate, lithium bismuthate, sodium bismuthate, Potassium bismuthate, lithium permanganate, potassium permanganate, sodium permanganate, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, sodium dichromate, lithium chromate, potassium chromate, chromium Sodium zirconate, lithium zirconate, sodium zirconate, potassium zirconate, lithium ferrate, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, lithium niobate, sodium niobate, potassium niobate , Lithium cobaltate, sodium cobaltate, potassium cobaltate, lithium nickelate, sodium nickelate, potassium nickelate, silicomomolybdic acid, silicotungstic acid, silicovanadate, ammonium molybdate, ammonium tungstate, ammonium vanadate, manganese ammonium dichromate, ammonium chromate or nickelate, phosphotungstic acid, phosphomolybdic acid and phosphovanadic acid.

Example 7.74-7.77

The porous graphene film samples were prepared according to the method of Example 7.1, except that the graphene film samples used were obtained from the preparatory examples 5.3-5.6.

Example 7.78-7.99

Prepare the porous graphene film sample according to the method of embodiment 7.1, the difference is that the etchant used is changed from ammonium molybdate to the cerium hydroxide suspension obtained by preliminary embodiment 3.1-3.22, and the concentration of the suspension is diluted 0.1mol/L.

Examples 7.100-7.107

The porous graphene film sample was prepared according to the method of Example 7.1, except that the etchant used was changed from ammonium molybdate to ferric oxide nanoparticles prepared in preliminary examples 4.1-4.8. The concentration of the ultrapure aqueous solution of iron ferric oxide nanoparticles is 0.1mol/L.

It can be seen from the above examples that porous graphene or porous graphene films can be successfully prepared by adopting the technical solutions of the present application, and the present invention can realize a large amount of porous graphene preparation. Compared with the previously reported preparation methods of porous graphene, this method has the following advantages:

(1) High output. The yield of the porous graphene prepared by this method is affected by the amount of feed, increasing the feed amount of the precursor, the yield can reach the gram level, and the pore size and pore density on the surface of the porous graphene can be adjusted by adjusting the ratio of etchant graphene in the precursor regulation. The method for preparing porous graphene in the comparative example is mainly aimed at the processing of single-sheet graphene or graphene film, and researches on making holes on its surface, and the output is very low, usually counted as "sheet".

(2) The equipment is simple. The present invention only needs to use a tube furnace (<2000 yuan) and a vacuum pump (<10,000 yuan) to complete the preparation of porous graphene or graphene film. In the comparison example, large-scale equipment such as scanning transmission electron microscope and helium ion microscope are needed, and the equipment price is very high (usually ranging from tens to several million yuan). At the same time, the method in the comparative example also has high requirements for the vacuum degree and cleanliness of the sample chamber.

It can be seen from Figure 4 and Figure 5 that the porous graphene film prepared in Example 6.1 uses an etchant of oxometalate, and heat treatment is used to create pores. The pore diameter is about 100 nm, and the pores are relatively dense. Wrinkles of graphene can also be observed. Figure 5 shows the porous graphene film prepared by the electron beam etching method. By using the electron beam to provide energy, the etchant can also etch holes on the surface of the graphene film. Compared with the thermal reduction method, the pore size and pore density Both are smaller.

Therefore, the present invention provides a method for preparing porous graphene in large quantities with relatively low cost, which is of great significance for the application research of porous graphene in the field of material science.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (10)

1. a preparation method of porous graphene, it is characterized in that, the method comprises, graphene and/or graphene oxide is mixed with etchant, obtains mixture; Under anaerobic conditions, carbon thermal reaction is carried out to mixture , and carry out acid treatment to remove unreacted and reacted etchant; the etchant is one or more of metal oxo-salt, metal hydroxide and metal oxide. 2. The method according to claim 1, wherein the mass ratio of the graphene and/or graphene oxide to the etchant is 0.1-10:1, preferably 0.5-2:1. 3. The method of claim 1, wherein, The oxometalates are sodium molybdate, potassium molybdate, lithium tungstate, sodium tungstate, potassium tungstate, lithium stannate, sodium stannate, potassium stannate, lithium aluminate, sodium aluminate, potassium aluminate , lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, potassium vanadate, lithium bismuthate, sodium bismuthate, potassium bismuthate, lithium permanganate, potassium permanganate, permanganate Sodium, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, sodium dichromate, lithium chromate, potassium chromate, sodium chromate, lithium zirconate, sodium zirconate, potassium zirconate, ferrate Lithium, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, lithium niobate, sodium niobate, potassium niobate, lithium cobaltate, sodium cobaltate, potassium cobaltate, lithium nickelate, Sodium nickelate, potassium nickelate, silicon molybdenum acid, silicon tungstic acid, silicon vanadium acid, ammonium molybdate, ammonium tungstate, ammonium vanadate, ammonium manganate, ammonium dichromate, ammonium chromate, ammonium nickelate, phosphorus One or more of tungstic acid, phosphomolybdic acid and phosphovanadic acid; The metal hydroxide is one or more hydroxides of Group IIA, IIIA, IB, IIB, IVB, VB, VIB, Group VIII and lanthanide metals; preferably, the metal hydroxide is Hydroxides of one or more of the metals magnesium, aluminum, copper, zinc, cadmium, titanium, zirconium, vanadium, niobium, molybdenum, iron, cobalt, nickel, ruthenium and lanthanum; The metal oxide is one or more oxides of Group IIIA, IB, IIB, IVB, VB and VIII metals; preferably, the metal oxide is aluminum, copper, zinc, chromium, zirconium, Oxides of one or more of the metals vanadium, iron, cobalt and nickel. 4. The method according to any one of claims 1-3, wherein the etchant is one or more of sodium aluminate, sodium molybdate and sodium tungstate. 5. The method according to claim 1, wherein the carbothermal reaction conditions include: a temperature of 300-1000° C. and a time of 5-300 minutes. 6. A preparation method for porous graphene film, characterized in that, the method comprises, dispersing etchant on graphene and/or graphene oxide film, carrying out carbon heat reaction under anaerobic conditions, and carrying out Acid treatment to remove unreacted or reacted etchant; said etchant is one or more of oxometalates, metal hydroxides and metal oxides. 7. The method according to claim 6, wherein the mass ratio of the graphene and/or graphene oxide to the etchant is 0.1-10:1, preferably 0.5-2:1. 8. The method of claim 6, wherein, The oxometalates are sodium molybdate, potassium molybdate, lithium tungstate, sodium tungstate, potassium tungstate, lithium stannate, sodium stannate, potassium stannate, lithium aluminate, sodium aluminate, potassium aluminate , lithium titanate, sodium titanate, potassium titanate, lithium titanate, sodium vanadate, potassium vanadate, lithium bismuthate, sodium bismuthate, potassium bismuthate, lithium permanganate, potassium permanganate, permanganate Sodium, lithium manganate, potassium manganate, sodium manganate, potassium dichromate, sodium dichromate, lithium chromate, potassium chromate, sodium chromate, lithium zirconate, sodium zirconate, potassium zirconate, ferrate Lithium, sodium ferrate, potassium ferrate, lithium zincate, sodium zincate, potassium zincate, lithium niobate, sodium niobate, potassium niobate, lithium cobaltate, sodium cobaltate, potassium cobaltate, lithium nickelate, Sodium nickelate, potassium nickelate, silicon molybdenum acid, silicon tungstic acid, silicon vanadium acid, ammonium molybdate, ammonium tungstate, ammonium vanadate, ammonium manganate, ammonium dichromate, ammonium chromate, ammonium nickelate, phosphorus One or more of tungstic acid, phosphomolybdic acid and phosphovanadic acid; The metal hydroxide is one or more hydroxides of Group IIA, IIIA, IB, IIB, IVB, VB, VIB, Group VIII and lanthanide metals; preferably, the metal hydroxide is Hydroxides of one or more of the metals magnesium, aluminum, copper, zinc, cadmium, titanium, zirconium, vanadium, niobium, molybdenum, iron, cobalt, nickel, ruthenium and lanthanum; The metal oxide is one or more oxides of Group IIIA, IB, IIB, IVB, VB and VIII metals; preferably, the metal oxide is aluminum, copper, zinc, chromium, zirconium, Oxides of one or more of the metals vanadium, iron, cobalt and nickel. 9. The method according to any one of claims 6-8, wherein the etchant is one or more of sodium aluminate, sodium molybdate and sodium tungstate. 10. The method according to claim 6, wherein the carbothermal reaction conditions include: a temperature of 300-1000° C. and a time of 5-300 minutes.