Preparation method of modified BN two-dimensional catalytic material and its application in methane conversion

Abstract

The present invention relates to the technical field of preparation of catalytic materials, specifically to a preparation method of a modified BN two-dimensional catalytic material and its application in methane conversion, wherein the preparation method comprises: S1. material mixing; S2. preparation of boron nitride material; S3. modification of boron nitride material; S4. post-processing. The modeling modified liquid prepared by the present invention through the oxygen stabilization enhancement liquid forms a heterojunction structure with the boron nitride material, which significantly promotes the separation of photogenerated electron-hole pairs, improves the kinetics of solar-driven catalytic reactions, and can also dynamically adjust the oxygen doping sites on the surface of the boron nitride material to prevent the loss of oxygen elements during the reaction, thereby ensuring the long-term stability of the catalytic material. The present invention helps to improve the efficiency of solar-catalyzed methane conversion and produce a large amount of carbon dioxide, thereby achieving high-yield production of high-value chemicals such as methanol or formaldehyde under mild conditions, and providing a new approach for green methane conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of catalytic materials, and specifically to a method for preparing a modified BN two-dimensional catalytic material and its application in methane conversion. Background Art

[0002] Methane (CH4), a key component of natural gas, has become a research hotspot in the energy and chemical industry. Direct conversion of methane to methanol (CH3OH) and formaldehyde (CH2O) has attracted significant attention due to its wide-ranging applications in energy storage, chemical production, and environmental protection. However, conventional methane conversion processes often face a number of challenges. Traditional methane-to-methanol processes typically involve multiple steps and demanding operating conditions. For example, the indirect conversion method requires partial oxidation of methane to produce carbon monoxide (CO) and hydrogen (H2), which are then further reacted to produce methanol. This multi-step process not only requires high temperatures and pressures, which consume considerable energy, but also easily produces byproducts (such as CO2 and CO), resulting in low reaction efficiency and a heavy environmental burden. Furthermore, the volatile deactivation and high cost of catalysts in conventional processes have limited their widespread application.

[0003] Compared with traditional processes, methane conversion technology based on solar-driven catalysis has shown in recent years to be greener and more efficient. Solar-driven catalysis uses sunlight as the driving force and achieves the selective oxidation of methane to produce methanol by designing efficient solar-driven catalytic materials. The significant advantages of this process are mild reaction conditions, high energy utilization, and low by-product generation, which meet the development needs of green chemical industry. In addition, the cost of solar-driven catalytic process materials is low, and the reaction process is more environmentally friendly. However, solar-driven catalytic methane conversion technology still faces some challenges, such as improving the conversion rate of methane and the yield of methanol. By continuously innovating the design of catalytic materials and optimizing reaction conditions, it is expected that solar-driven catalytic technology can be promoted to industrial applications, opening up new paths for the efficient utilization of methane resources and green chemical industry.

[0004] Currently, catalytic materials used for solar-driven methane conversion primarily focus on two-dimensional metal oxides (such as TiO2 and ZnO). These materials possess excellent light absorption properties, but are susceptible to product overoxidation in the presence of oxygen. Therefore, there is an urgent need to design efficient solar-driven catalytic materials that can improve methanol yield while suppressing product overoxidation. In this area of catalytic material selection, several two-dimensional non-metallic materials are gaining increasing attention. Among them, the non-toxic and harmless BN material has been discovered and applied to solar-driven methane conversion. This material produces only C1 compounds (methanol and formaldehyde) and no other peroxides (CO and CO2), making it an excellent catalyst for solar-driven methane conversion. However, the product yields obtained from single BN materials are low, and BN materials are currently being modified to be more suitable for solar-driven methane conversion. Several methods for modifying BN materials have been published, but they still have shortcomings, as detailed below.

[0005] CN119463532A discloses a method for ozone-modifying hexagonal boron nitride, belonging to the field of inorganic filler modification methods. This invention heat-treats hexagonal boron nitride at low temperatures, mixes it with water, and forms a slurry. Ozone is then introduced for oxidation, and finally, a surface modifier is used to modify the hexagonal boron nitride. The hydrolyzable groups in the surface modifier bind to the hydroxyl groups on the surface of the boron nitride, resulting in more carbon-containing long chains on the surface of the boron nitride. Therefore, the more modifier added, the higher the carbon content. Excess free modifier is removed using butanone. The carbon content measured at this point is the amount of modifier grafted onto the boron nitride surface; a higher carbon content indicates more successfully grafted surface modifier. However, this method requires butanone to remove the free modifier, which can lead to incomplete removal.

[0006] CN119307073A discloses a method for preparing a highly thermally conductive polymer using modified boron nitride as a filler, relating to the field of polymer thermal conductivity technology. The invention's method for preparing modified boron nitride nanosheets involves adding boron nitride nanosheets to 10ml of tetrahydrofuran and ultrasonically dispersing them at 400W for 10 minutes. A modifier is then added and the mixture reacts at 40°C for 2 hours. The tetrahydrofuran is then removed in a rotary evaporator at 65°C and 400mmHg at 100 rpm. The mixture is then transferred to 40ml of deionized water and dried in an 80°C oven for 12 hours to obtain the modified boron nitride nanosheets. Amino modification of the boron nitride nanosheets stabilizes their structure and properties, effectively enhancing their interfacial compatibility and dispersibility with the polymer matrix. However, this method requires numerous temperature changes during synthesis, making the process relatively cumbersome. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a modified BN two-dimensional catalytic material and its application in methane conversion.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for preparing a modified BN two-dimensional catalytic material comprises the following preparation steps:

[0010] S1. Material mixing: Boric acid and urea were added to a beaker in a mass ratio of 12:1 and mechanically stirred at 400-500 rpm for 0.5-2 h to thoroughly mix the two to obtain a white powder.

[0011] S2. Preparation of boron nitride material: The white powder obtained in step S1 was transferred to a porcelain boat, placed in a tube furnace for heat treatment, then naturally cooled to room temperature, and finally ground to obtain a boron nitride material;

[0012] S3. Modification of the boron nitride material: A certain amount of the boron nitride material prepared in step S2 was mixed with the modeling modification solution, placed in a beaker, and ultrapure water was added and stirred evenly. After that, the synergistic modification solution was added and stirred for 15-20 minutes. The reaction apparatus was then heated in a water bath at 80°C for 3-4 hours to obtain the modified boron nitride material.

[0013] S4. Post-processing: The modified boron nitride material is filtered and separated using a suction filtration device, and repeatedly washed with ultrapure water. The residual solid is then precipitated onto filter paper, and the resulting solid is dried in a vacuum drying oven, and then ground to obtain a modified BN two-dimensional catalytic material;

[0014] The preparation of the modeling modification solution includes the following steps:

[0015] S11. In parts by mass, 6-10 parts of zinc oxide, 0.5-1 parts of polyethylene glycol were added to 50-60 parts of ultrapure water and ultrasonically dispersed at a frequency of 40 kHz for 25-30 min to obtain a uniform suspension;

[0016] S12. Add 2-5 parts of oxygen stabilization enhancement solution to the suspension obtained in step S11 and stir at a speed of 500-600r / min at room temperature for 15-20min;

[0017] S13. Add 1.5-2 parts of aluminum nitrate to the mixed solution obtained in step S12, and stir at a speed of 450-500 r / min at room temperature for 25-30 minutes to obtain a modeling modification solution.

[0018] Preferably, the preparation of the oxygen stabilization enhancement solution comprises the following steps:

[0019] S121. In parts by mass, 50-55 parts of ammonium cerium nitrate and 8-10 parts of lanthanum nitrate were dissolved in 180-200 parts of ultrapure water and stirred at 40 ° C at a speed of 300-400r / min for 15-20min;

[0020] S122. Add 25-30 parts of citric acid to the solution obtained in step S121, and continue stirring at a speed of 350-400 r / min for 0.5-1 h to obtain an oxygen stabilization enhancement solution.

[0021] Preferably, the synergistic modification liquid consists of phosphomolybdic acid, glacial acetic acid and water in a mass ratio of 0.05-0.1:1:10.

[0022] Preferably, the specific control conditions of the heat treatment in step S2 are a heating rate of 5°C / s, a holding time of 5h, a nitrogen atmosphere during the period, a starting temperature of 25°C, and an end temperature of 1000°C.

[0023] Preferably, in step S3, the mass ratio of the boron nitride material, the modeling modification liquid, and the synergistic modification liquid is 1:1:0.1-0.2.

[0024] Preferably, the stirring speed in step S3 is 500-600 r / min.

[0025] Preferably, the drying treatment control conditions in step S4 are a drying temperature of 60° C. and a duration of 12 hours.

[0026] A modified BN two-dimensional catalytic material prepared according to the preparation method is used as a catalyst for a solar-driven methane conversion reaction.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention features a simple preparation process, low energy consumption in the solar-driven catalytic methane conversion step, and significant cost advantages. It also helps improve the efficiency of solar-driven catalytic methane conversion and generate large amounts of carbon dioxide, enabling high yields of high-value chemicals such as methanol and formaldehyde under mild conditions, providing a new approach to green methane conversion.

[0029] 2. The modeling modified liquid prepared by the oxygen stabilization enhancement liquid of the present invention forms a heterojunction structure with the boron nitride material, which significantly promotes the separation of photogenerated electron-hole pairs, improves the kinetics of solar-driven catalytic reactions, and can also dynamically adjust the oxygen doping sites on the surface of the boron nitride material to prevent the loss of oxygen elements during the reaction, thereby ensuring the long-term stability of the catalytic material.

[0030] 3. The synergistic effect of the modeling modification fluid, oxygen stabilization enhancement fluid, and synergistic modification fluid in the present invention provides oxygen, which can prevent the overoxidation of the products methanol or formaldehyde during the reaction process, thereby increasing the yield of methanol or formaldehyde. The surface structure of the boron nitride material is modified, resulting in excellent solar-driven catalytic performance. This catalytic material can selectively generate methanol or formaldehyde from methane at room temperature and pressure, with a yield of nearly 1000 μmol·g -1 , realizing the rational utilization of methane resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the preparation process of the modified BN two-dimensional catalytic material of the present invention;

[0032] Figure 2 The following is a flow chart of the preparation process of the modeling modified liquid of the present invention;

[0033] Figure 3 This is a process flow chart for preparing the oxygen stabilization enhancement solution of the present invention;

[0034] Figure 4 This is a transmission electron microscopy morphology image of the modified BN two-dimensional catalytic material obtained in Example 1 of the present invention;

[0035] Figure 5 Graph showing the methanol yield of the solar-driven catalytic methane conversion of the modified BN two-dimensional catalytic materials prepared in Example 1, Example 2, and Comparative Example 1 of the present invention;

[0036] Figure 6 This is a graph of the CO2 yield of the solar-driven catalytic methane conversion of the modified BN two-dimensional catalytic material prepared in Example 1, Example 2 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] See also Figure 1-6 , the present invention provides a technical solution:

[0039] Example 1

[0040] A method for preparing a modified BN two-dimensional catalytic material:

[0041] Before preparing the modified BN two-dimensional catalytic material, the modeling modification liquid and the oxygen stabilization enhancement liquid are prepared:

[0042] The preparation of the modeling modification solution includes the following steps:

[0043] S11. 12 g of zinc oxide and 1 g of polyethylene glycol were added to 100 ml of ultrapure water and ultrasonically dispersed at a frequency of 40 kHz for 25 min to obtain a uniform suspension;

[0044] S12. 4 g of oxygen stabilization enhancing solution was added to the suspension obtained in step S11 and stirred at a speed of 500 r / min at room temperature for 15 min;

[0045] S13 was added 3g of aluminum nitrate to the mixture obtained in step S12, stirred at a speed of 450r / min at room temperature for 25min to obtain a modeling modified liquid;

[0046] The preparation of the oxygen stabilization enhancement solution comprises the following steps:

[0047] S121. 50 g of ammonium cerium nitrate and 8 g of lanthanum nitrate were dissolved in 180 ml of ultrapure water and stirred at 300 r / min at 40 ° C for 15 min;

[0048] S122. Add 25 g of citric acid to the solution obtained in step S121, and continue stirring at a speed of 350 r / min for 0.5 h to obtain an oxygen stabilization enhanced solution.

[0049] S1. Material mixing: Boric acid and urea were added to a beaker in a mass ratio of 12:1. The mixture was thoroughly mixed by mechanical stirring at 400 rpm for 0.5 h to obtain a white powder.

[0050] S2. Preparation of boron nitride material: The white powder obtained in step S1 was transferred to a porcelain boat and placed in a tube furnace for heat treatment. The specific control conditions for the heat treatment were a heating rate of 5°C / s, a holding time of 5h, a nitrogen atmosphere during which the starting temperature was 25°C and the end temperature was 1000°C. The mixture was then naturally cooled to room temperature and finally ground to obtain a boron nitride material.

[0051] S3. Modification of the boron nitride material: 100 g of the boron nitride material prepared in step S2 was mixed with 100 g of the modeling modification liquid, placed in a beaker, and ultrapure water was added and stirred at a speed of 500 r / min. Then, 10 g of the synergistic modification liquid (composed of 0.5 g of phosphomolybdic acid, 10 g of glacial acetic acid, and 100 ml of water, 10 g of which was taken) was added and stirred at a speed of 500 r / min for 15 min. The reaction apparatus was then heated in a water bath at 80°C for 3 h to obtain the modified boron nitride material;

[0052] S4. Post-processing: The modified boron nitride material is filtered and separated by a suction filtration device, and repeatedly washed with ultrapure water. The residual solid is then precipitated on filter paper, and the obtained solid is placed in a vacuum drying oven for drying. The drying treatment control conditions are a drying temperature of 60°C and a duration of 12 hours. The modified BN two-dimensional catalytic material is then obtained by grinding.

[0053] Example 2

[0054] A method for preparing a modified BN two-dimensional catalytic material:

[0055] Before preparing the modified BN two-dimensional catalytic material, the modeling modification liquid and the oxygen stabilization enhancement liquid are prepared:

[0056] The preparation of the modeling modification solution includes the following steps:

[0057] S11. 20 g of zinc oxide and 2 g of polyethylene glycol were added to 120 ml of ultrapure water and ultrasonically dispersed at a frequency of 40 kHz for 30 min to obtain a uniform suspension;

[0058] S12. 10 g of oxygen stabilization enhancement solution was added to the suspension obtained in step S11 and stirred at a speed of 600 r / min at room temperature for 20 min;

[0059] S13 was added 4g of aluminum nitrate to the mixture obtained in step S12, stirred at a speed of 500r / min at room temperature for 30min to obtain a modeling modified liquid;

[0060] The preparation of the oxygen stabilization enhancement solution comprises the following steps:

[0061] S121. 55 g of ammonium cerium nitrate and 10 g of lanthanum nitrate were dissolved in 200 ml of ultrapure water and stirred at 40 ° C at a speed of 400 r / min for 20 min;

[0062] S122. Add 30 g of citric acid to the solution obtained in step S121, and continue stirring at a speed of 400 r / min for 1 hour to obtain an oxygen stabilization enhanced solution.

[0063] S1. Material mixing: Boric acid and urea were added to a beaker in a mass ratio of 12:1. The mixture was thoroughly mixed by mechanical stirring at 500 rpm for 2 h to obtain a white powder.

[0064] S2. Preparation of boron nitride material: The white powder obtained in step S1 was transferred to a porcelain boat and placed in a tube furnace for heat treatment. The specific control conditions for the heat treatment were a heating rate of 5°C / s, a holding time of 5h, a nitrogen atmosphere during which the starting temperature was 25°C and the end temperature was 1000°C. The mixture was then naturally cooled to room temperature and finally ground to obtain a boron nitride material.

[0065] S3. Modification of the boron nitride material: 100 g of the boron nitride material prepared in step S2 was mixed with 100 g of the modeling modification liquid, placed in a beaker, and ultrapure water was added and stirred at 600 r / min. Then, 20 g of the synergistic modification liquid (composed of 1 g of phosphomolybdic acid, 10 g of glacial acetic acid, and 100 ml of water, 20 g of which was taken) was added. Stirring was continued at 600 r / min for 20 min, and the reaction apparatus was heated in a water bath at 80°C for 4 h to obtain the modified boron nitride material;

[0066] S4. Post-processing: The modified boron nitride material is filtered and separated by a suction filtration device, and repeatedly washed with ultrapure water. The residual solid is then precipitated on filter paper, and the obtained solid is placed in a vacuum drying oven for drying. The drying treatment control conditions are a drying temperature of 60°C and a duration of 12 hours. The modified BN two-dimensional catalytic material is then obtained by grinding.

[0067] Example 3

[0068] A method for preparing a modified BN two-dimensional catalytic material:

[0069] Before preparing the modified BN two-dimensional catalytic material, the modeling modification liquid and the oxygen stabilization enhancement liquid are prepared:

[0070] The preparation of the modeling modification solution includes the following steps:

[0071] S11. 15 g of zinc oxide and 1.5 g of polyethylene glycol were added to 110 ml of ultrapure water and ultrasonically dispersed at a frequency of 40 kHz for 27 min to obtain a uniform suspension;

[0072] S12. 5 g of oxygen stabilization enhancing solution was added to the suspension obtained in step S11 and stirred at a speed of 550 r / min at room temperature for 17 min;

[0073] S13 was added 3.5g of aluminum nitrate to the mixture obtained in step S12, stirred at a speed of 470r / min at room temperature for 27min to obtain a modeling modified liquid;

[0074] The preparation of the oxygen stabilization enhancement solution comprises the following steps:

[0075] S121. 52 g of ammonium cerium nitrate and 9 g of lanthanum nitrate were dissolved in 190 ml of ultrapure water and stirred at 350 r / min at 40 ° C for 17 min;

[0076] S122. Add 27 g of citric acid to the solution obtained in step S121, and continue stirring at a speed of 370 r / min for 0.7 h to obtain an oxygen stabilization enhanced solution.

[0077] S1. Material mixing: Boric acid and urea were added to a beaker in a mass ratio of 12:1. The mixture was thoroughly mixed by mechanical stirring at 450 rpm for 1 h to obtain a white powder.

[0078] S2. Preparation of boron nitride material: The white powder obtained in step S1 was transferred to a porcelain boat and placed in a tube furnace for heat treatment. The specific control conditions for the heat treatment were a heating rate of 5°C / s, a holding time of 5h, a nitrogen atmosphere during which the starting temperature was 25°C and the end temperature was 1000°C. The mixture was then naturally cooled to room temperature and finally ground to obtain a boron nitride material.

[0079] S3. Modification of boron nitride material: 100 g of the boron nitride material prepared in step S2 was mixed with 100 g of the modeling modification liquid, placed in a beaker, and ultrapure water was added and stirred at a speed of 550 r / min. Then, 15 g of the synergistic modification liquid (composed of 0.7 g of phosphomolybdic acid, 10 g of glacial acetic acid, and 100 ml of water, 15 g of which was taken) was added. Stirring was continued at a speed of 550 r / min for 17 min, and the reaction apparatus was heated in a water bath at a temperature of 80°C for a reaction time of 3.5 h to obtain the modified boron nitride material;

[0080] S4. Post-processing: The modified boron nitride material is filtered and separated by a suction filtration device, and repeatedly washed with ultrapure water. The residual solid is then precipitated on filter paper, and the obtained solid is placed in a vacuum drying oven for drying. The drying treatment control conditions are a drying temperature of 60°C and a duration of 12 hours. The modified BN two-dimensional catalytic material is then obtained by grinding.

[0081] Example 4

[0082] A method for preparing a modified BN two-dimensional catalytic material:

[0083] Before preparing the modified BN two-dimensional catalytic material, the modeling modification liquid and the oxygen stabilization enhancement liquid are prepared:

[0084] The preparation of the modeling modification solution includes the following steps:

[0085] S11. 17 g of zinc oxide and 1.7 g of polyethylene glycol were added to 115 ml of ultrapure water and ultrasonically dispersed at a frequency of 40 kHz for 29 min to obtain a uniform suspension;

[0086] S12. 8 g of oxygen stabilization enhancement solution was added to the suspension obtained in step S11 and stirred at a speed of 570 r / min at room temperature for 19 min;

[0087] S13 was added 3.8g of aluminum nitrate to the mixture obtained in step S12, stirred at a speed of 480r / min at room temperature for 29min to obtain a modeling modified liquid;

[0088] The preparation of the oxygen stabilization enhancement solution comprises the following steps:

[0089] S121. 53 g of ammonium cerium nitrate and 9 g of lanthanum nitrate were dissolved in 195 ml of ultrapure water and stirred at 370 r / min at 40 ° C for 18 min;

[0090] S122. Add 28 g of citric acid to the solution obtained in step S121, and continue stirring at a speed of 390 r / min for 0.8 h to obtain an oxygen stabilization enhanced solution.

[0091] S1. Material mixing: Boric acid and urea were added to a beaker in a mass ratio of 12:1. The mixture was thoroughly mixed by mechanical stirring at 480 rpm for 1.5 h to obtain a white powder.

[0092] S2. Preparation of boron nitride material: The white powder obtained in step S1 was transferred to a porcelain boat and placed in a tube furnace for heat treatment. The specific control conditions for the heat treatment were a heating rate of 5°C / s, a holding time of 5h, a nitrogen atmosphere during which the starting temperature was 25°C and the end temperature was 1000°C. The mixture was then naturally cooled to room temperature and finally ground to obtain a boron nitride material.

[0093] S3. Modification of boron nitride material: 100 g of the boron nitride material obtained in step S2 was mixed with 100 g of the modeling modification liquid, placed in a beaker, and ultrapure water was added and stirred at a speed of 580 r / min. Then, 18 g of the synergistic modification liquid (composed of 0.8 g of phosphomolybdic acid, 10 g of glacial acetic acid and 100 ml of water, 18 g of which was taken) was added and stirred at a speed of 580 r / min for 18 min. The reaction apparatus was then heated in a water bath at 80°C for a reaction time of 3.5 h to obtain the modified boron nitride material;

[0094] S4. Post-processing: The modified boron nitride material is filtered and separated by a suction filtration device, and repeatedly washed with ultrapure water. The residual solid is then precipitated on filter paper, and the obtained solid is placed in a vacuum drying oven for drying. The drying treatment control conditions are a drying temperature of 60°C and a duration of 12 hours. The modified BN two-dimensional catalytic material is then obtained by grinding.

[0095] Comparative Example 1

[0096] Comparative Example 1 differs from Example 1 in that step S3 and step S4 are omitted, and the boron nitride material is directly obtained. The remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0097] Performance testing:

[0098] The modified BN two-dimensional catalytic materials prepared in Example 1 and Example 2, and the boron nitride material prepared in Comparative Example 1 were tested for catalytic performance. Example 1 and Example 2 were further named O-BN-1 and O-BN-2, and Comparative Example 1 was named BN, and then used in the solar-driven catalytic methane conversion to methanol experiment: 20 mg of O-BN-1, O-BN-2, and BN were respectively placed in three transparent closed reactors, 20 mL of ultrapure water was added, and the reactor was sealed and placed on a stirring table for stirring; O2 gas was purged for 10 minutes to remove impurity gases in the system; 5 mL of dry CH4 gas was quickly injected into the reactor with a sampling needle to ensure that the system was constant at 60°C; a circulating water cooling system was connected, and a xenon lamp was turned on for light reaction; 1 mL of gas was sampled every 0.5 h during the reaction for gas chromatography analysis to monitor the reaction progress; the reaction was maintained for 2 h and then ended. The entire experimental process was carried out under normal temperature and pressure conditions.

[0099] Attachment Figure 3 This is a transmission electron microscopy morphology of the modified BN two-dimensional catalytic material obtained in Example 1 of the present invention. It can be observed from the figure that the modified BN material presents a uniform two-dimensional layered structure with a nanoscale heterojunction structure distributed on the surface, indicating that the modeling modification liquid and the boron nitride matrix have successfully formed an interface coupling. The introduction of this heterojunction structure significantly promotes the separation efficiency of photogenerated electron-hole pairs, thereby improving the kinetics of solar-driven catalytic reactions. Figure 4 It can be seen that the methanol yield obtained by solar-driven catalytic methane conversion for 2 h at room temperature and pressure is close to 1000 μmol·g -1 The methanol yield obtained by Example 2 is lower than that obtained by Example 1. Figure 5 , the modified BN two-dimensional catalytic material prepared in Example 1 is used to carry out a solar-driven catalytic reaction, and a yield graph of the product CO2 can be obtained. As can be seen from the results, when the solar-driven catalytic methane conversion is carried out at room temperature and pressure for 2 hours, the CO2 yield obtained is low, while the catalytic material obtained by using Example 2 has a higher CO2 yield than that of Example 1. The methanol yield of the solar-driven catalytic methane conversion of the modified BN two-dimensional catalytic material obtained in Example 1 is higher than that of Example 2, and the CO2 yield of the solar-driven catalytic methane conversion of the modified BN two-dimensional catalytic material obtained in Example 2 is higher than that of Example 1, but the methanol yield and CO2 yield of the solar-driven catalytic methane conversion of the modified BN two-dimensional catalytic materials obtained in Examples 1 and 2 are much higher than those of Comparative Example 1.

[0100] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a modified BN two-dimensional catalytic material, characterized in that: The method comprises the following preparation steps: S1. Material mixing: Boric acid and urea were added to a beaker in a mass ratio of 12:1 and mechanically stirred at 400-500 rpm for 0.5-2 h to thoroughly mix the two to obtain a white powder. S2. Preparation of boron nitride material: The white powder obtained in step S1 was transferred to a porcelain boat, placed in a tube furnace for heat treatment, then naturally cooled to room temperature, and finally ground to obtain a boron nitride material; S3. Modification of the boron nitride material: A certain amount of the boron nitride material prepared in step S2 was mixed with the modeling modification solution, placed in a beaker, and ultrapure water was added and stirred evenly. After that, the synergistic modification solution was added and stirred for 15-20 minutes. The reaction apparatus was then heated in a water bath at 80°C for 3-4 hours to obtain the modified boron nitride material. S4. Post-processing: The modified boron nitride material is filtered and separated using a suction filtration device, and repeatedly washed with ultrapure water. The residual solid is then precipitated onto filter paper, and the resulting solid is dried in a vacuum drying oven, and then ground to obtain a modified BN two-dimensional catalytic material; The preparation of the modeling modification liquid comprises the following steps: S11. In parts by mass, 6-10 parts of zinc oxide, 0.5-1 parts of polyethylene glycol were added to 50-60 parts of ultrapure water and ultrasonically dispersed at a frequency of 40 kHz for 25-30 min to obtain a uniform suspension; S12. Add 2-5 parts of oxygen stabilization enhancement solution to the suspension obtained in step S11 and stir at a speed of 500-600r / min at room temperature for 15-20min; S13. 1.5-2 parts of aluminum nitrate were added to the mixture obtained in step S12 and stirred at a speed of 450-500 r / min at room temperature for 25-30 min to obtain a modeling modified liquid; The preparation of the oxygen stabilization enhancement solution comprises the following steps: S121. In parts by mass, 50-55 parts of ammonium cerium nitrate and 8-10 parts of lanthanum nitrate were dissolved in 180-200 parts of ultrapure water and stirred at 40 ° C at a speed of 300-400r / min for 15-20min; S122. Add 25-30 parts of citric acid to the solution obtained in step S121 and continue stirring at a speed of 350-400 r / min for 0.5-1h to obtain an oxygen-stabilized enhanced solution; The synergistic modification liquid consists of phosphomolybdic acid, glacial acetic acid and water in a mass ratio of 0.05-0.1:1:

10.

2. The method for preparing a modified BN two-dimensional catalytic material according to claim 1, characterized in that: The specific control conditions of the heat treatment in step S2 are a heating rate of 5°C / s, a holding time of 5h, a nitrogen atmosphere during the period, a starting temperature of 25°C, and an end temperature of 1000°C.

3. The method for preparing a modified BN two-dimensional catalytic material according to claim 1, characterized in that: In step S3, the mass ratio of the boron nitride material, the modeling modification liquid, and the synergistic modification liquid is 1:1:0.1-0.

2.

4. The method for preparing a modified BN two-dimensional catalytic material according to claim 1, characterized in that: The stirring speed in step S3 is 500-600 r / min.

5. The method for preparing a modified BN two-dimensional catalytic material according to claim 1, characterized in that: The drying treatment control conditions in step S4 are a drying temperature of 60° C. and a duration of 12 h.

6. Use of a modified BN two-dimensional catalytic material prepared according to the preparation method according to any one of claims 1 to 5 as a catalyst for solar-driven catalytic methane conversion reaction.

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