Preparation method of nitrogen-doped ultrathin nanosheet support microspherical carbon material

Abstract

The present application relates to the technical field of carbon material preparation, and particularly relates to a preparation method of nitrogen-doped ultrathin nanosheet support microspherical carbon material. The preparation method of the microspherical carbon material comprises the following steps: mixing gallium salt, zinc salt, carbon precursor, amine compound and water, and performing a solvothermal reaction to obtain deep red powder solid; and then performing calcination on the deep red powder solid in an inert atmosphere, and performing acid washing, water washing and drying to obtain the microspherical carbon material. The residual template agent after calcination can be removed completely by using dilute hydrochloric acid, thereby avoiding the use of strong corrosive reagents such as HF, KOH or NaOH. The method realizes batch production of the synthesis of the nitrogen-doped ultrathin nanosheet support microspherical carbon material, is simple to operate, stable in process, and regular in product morphology, and the amount of gallium salt and amine compound is reduced. The Pd(OH)2 / C catalyst prepared by using the material as a carrier shows excellent catalytic activity in the hydrogenolysis debenzyl reaction of a cage-shaped substrate.

Description

Technical Field

[0001] This invention relates to the field of carbon material preparation technology, and in particular to a method for preparing nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material. Background Technology

[0002] Hexanitrohexaazaisowulzane (CL-20) is a high-energy-density material. To date, the optimal process for synthesizing CL-20 involves amine-aldehyde condensation, two hydrogenolysis debenzylation processes, nitration, and crystallization. The two hydrogenolysis debenzylation processes are the key steps in the synthesis of CL-20. The catalytic conversion of the N-benzyl group is a crucial step in the synthesis of this type of energetic molecule, but due to the poor stability of the polynitrogenous cage-like framework, the requirements for the debenzylation catalyst are extremely high. Commercial palladium-based catalysts suffer from low activity, easy deactivation, and high Pd content, becoming a bottleneck limiting the synthesis of this type of energetic molecule, especially its large-scale preparation. It is well known that the type of Pd precursor, the intrinsic properties of the carbon support, and the preparation method of the Pd / C catalyst significantly affect the dispersion, particle size, and distribution of Pd in ​​the support channels, thus influencing the activity of the palladium-based catalyst. The choice of carbon support material is particularly important, as the properties of the support not only affect the morphology, particle size distribution, and dispersion of the active component Pd, but also the ease with which the reaction substrate approaches the active site. Therefore, developing efficient and environmentally friendly methods for preparing porous carbon nanomaterials is of great significance.

[0003] Porous carbon materials, as carbonaceous substances with a hierarchical pore structure, especially porous carbon, possess highly developed pore structures, high specific surface areas, and easily controllable surface chemical properties, making them applicable to fields such as gas adsorption, catalysis, water treatment, drug delivery, and energy conversion / storage. Currently, porous carbon materials are typically prepared by carbonizing, activating, and modifying natural or artificially synthesized precursors. To date, representative synthetic methods for porous carbon materials include: (1) physical, chemical, or physical-chemical composite activation methods; (2) template replication methods; (3) thermal decomposition of organic salt compounds; (4) preparation of porous carbon materials using metal-organic frameworks; (5) sol-gel carbonization methods; and (6) carbonization of precursor compounds composed of unstable and easily thermally decomposed components. Although porous carbon materials can be prepared using these different methods, synthesizing the desired material remains a significant challenge. Compared with traditional activation methods, template-based methods for preparing carbon materials offer several advantages: the pore size and distribution of porous carbon materials can be controlled; reaction temperature and energy consumption are reduced; and corrosion of the carbon framework is avoided while maintaining a high carbonization rate. Benefiting from these advantages, template-based methods have become a routine, effective, and promising approach in recent years. Therefore, developing an efficient method for preparing nitrogen-doped ultrathin nanosheet scaffold microsphere carbon materials using template agents would be a highly meaningful endeavor. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material, thereby obtaining a solvothermal synthesized nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material, which is then used as a support for a Pd(OH)2 / C catalyst in the dehydrobenzyl hydrolysis process.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material, comprising the following steps:

[0007] Step 1) Gallium salt, zinc salt, carbon precursor, amine compound and water are mixed and subjected to a solvothermal reaction to obtain a dark red powder solid;

[0008] Step 2) The dark red powder solid from Step 1) is calcined under an inert atmosphere, and then acid-washed, water-washed, and dried to obtain microsphere carbon material.

[0009] Optionally, the gallium salt comprises one or more of gallium nitrate, gallium acetate, and gallium chloride;

[0010] The zinc salt comprises one or more of zinc acetate, zinc nitrate, and zinc carbonate.

[0011] Optionally, the carbon precursor comprises glucose, maltose, fructose, sucrose, or cellulose;

[0012] The amine organic compounds include one or more of ethylenediamine, triethylamine, triethanolamine, and diethylamine.

[0013] Optionally, the molar ratio of zinc salt to gallium salt is 0.1 to 4:1;

[0014] The concentration of the zinc salt mixed with water is 0.01–0.4 mol / L, and the concentration of the gallium salt mixed with water is 0.01–0.4 mol / L.

[0015] Optionally, the volume ratio of the amine compound to water is 1:0.5 to 2;

[0016] The concentration of the carbon precursor mixed with water is 0.01–1.0 mol / L.

[0017] Optionally, the temperature of the solvothermal reaction is 150–220°C, and the time is 18–24 h.

[0018] Optionally, the calcination temperature is 500–1200°C, and the time is 2–4 hours.

[0019] Optionally, the inert gas includes one or more of nitrogen, helium, and argon.

[0020] The present invention also provides nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material prepared by the above preparation method. Each carbon sphere is composed of multiple carbon nanosheets stacked in an orderly manner. The diameter of the microsphere carbon material is 1-4 μm and the thickness of the nanosheets is 10-60 nm.

[0021] This invention also provides the application of the Pd(OH)2 / C catalyst prepared using the above-mentioned microsphere carbon material as a support in the debenzylation of hydrogen.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention involves adding water-soluble zinc salt, water-soluble gallium salt, and a carbon precursor to a mixed solution of amine compounds and water in a specific ratio. After thorough stirring, the resulting suspension undergoes a solvothermal reaction, followed by calcination to obtain nitrogen-doped ultrathin nanosheet scaffold microsphere carbon materials. Furthermore, any residual template agent after calcination can be completely removed with dilute hydrochloric acid, avoiding the use of strong corrosive reagents such as HF, KOH, or NaOH. This method enables the mass production of nitrogen-doped ultrathin nanosheet scaffold microsphere carbon materials, offering simple operation, stable process, and easily controllable product morphology, while reducing the amount of gallium salt and amine compounds required.

[0024] This invention successfully synthesized a nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material using biomass as the carbon source and a solvothermal carbonization method. The Pd(OH)₂ / C catalyst prepared using this material as a support exhibited excellent catalytic activity in the hydrodebenzylation reaction of cage-like substrates. Attached Figure Description

[0025] Figure 1 A scanning electron microscope image of the white powder of the 1-1# ultrathin nanosheet scaffold microspheres prepared in Comparative Example 1;

[0026] Figure 2 The image shows a scanning electron microscope (SEM) image of the nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material prepared in Example 1.

[0027] Figure 3 X-ray diffraction pattern of white powder of ultrathin nanosheet scaffold microspheres prepared in Comparative Example 1 (1-1#);

[0028] Figure 4 The X-ray diffraction pattern of the nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material prepared in Example 1 is shown below.

[0029] Figure 5 This is a scanning electron microscope image of the nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material No. 5 prepared in Comparative Example 2;

[0030] Figure 6 This is a scanning electron microscope image of the nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material No. 6 prepared in Comparative Example 3;

[0031] Figure 7 The activity diagram of the catalyst prepared in HBIW using nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material as a support, as shown in Examples 1-2 and Comparative Examples 2-3. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0036] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0037] This invention provides a method for preparing nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material, comprising the following steps:

[0038] Step 1) Gallium salt, zinc salt, carbon precursor, amine compound and water are mixed and subjected to a solvothermal reaction to obtain a dark red powder solid;

[0039] Step 2) The dark red powder solid from Step 1) is calcined under an inert atmosphere, and then acid-washed, water-washed, and dried to obtain microsphere carbon material.

[0040] In this invention, the most preferred mixing method in step 1) is to add gallium salt, zinc salt, and carbon precursor to amine organic compound and deionized water, and stir to form a uniform brownish-red solution.

[0041] In this invention, the specific steps of the solvothermal reaction in step 1) are to transfer the above-mentioned brownish-red solution into a polytetrafluoroethylene liner, and then place the liner into a stainless steel self-pressurized autoclave, and perform solvothermal treatment at a certain temperature to obtain a dark red powder solid.

[0042] In this invention, step 2) involves placing the dark red powder from step 1) in a tube furnace and calcining it under an inert atmosphere to obtain a black powder solid. The black powder solid is then placed in a dilute hydrochloric acid solution of a certain concentration and stirred to remove the template agent. After filtration, washing, and drying, nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material is obtained.

[0043] In this invention, the gallium salt comprises one or more of gallium nitrate, gallium acetate, and gallium chloride, preferably one or two of gallium nitrate and gallium acetate, and most preferably gallium nitrate.

[0044] The zinc salt comprises one or more of zinc acetate, zinc nitrate, and zinc carbonate, preferably one or two of zinc acetate and zinc nitrate, and most preferably zinc acetate.

[0045] In this invention, the carbon precursor comprises glucose, maltose, fructose, sucrose or cellulose, preferably glucose, maltose, fructose or sucrose, more preferably glucose, maltose or fructose, and even more preferably glucose.

[0046] The amine organic compound comprises one or more of ethylenediamine, triethylamine, triethanolamine, and diethylamine, preferably one or more of ethylenediamine, triethylamine, and triethanolamine, and more preferably one or two of ethylenediamine and triethylamine.

[0047] In this invention, the molar ratio of zinc salt to gallium salt is 0.1 to 4:1, preferably 0.5 to 3.5:1, more preferably 1 to 3:1, and even more preferably 1.5 to 2:1;

[0048] The concentration of the zinc salt mixed with water is 0.01–0.4 mol / L, preferably 0.05–0.35 mol / L, more preferably 0.1–0.3 mol / L, and even more preferably 0.2–0.25 mol / L. The concentration of the gallium salt mixed with water is 0.01–0.4 mol / L, preferably 0.05–0.35 mol / L, more preferably 0.1–0.3 mol / L, and even more preferably 0.2–0.25 mol / L.

[0049] In this invention, by adjusting the amount of amine compounds, different nitrogen doping amounts can be achieved, and the morphology of the template agent can be precisely controlled, thereby realizing the synthesis of nitrogen-doped ultrathin nanosheet scaffold microsphere carbon materials.

[0050] In this invention, the volume ratio of the amine compound to water is 1:0.5 to 2, preferably 1:0.8 to 1.8, more preferably 1:1 to 1.5, and even more preferably 1:1.2 to 1.4;

[0051] The concentration of the carbon precursor mixed with water is 0.01–1.0 mol / L, preferably 0.05–0.5 mol / L, and more preferably 0.08–0.2 mol / L.

[0052] In this invention, by adjusting the molar ratio of gallium salt, zinc salt, and amine compounds, the amount of template agent can be reduced while maintaining the specific morphology of carbon, thereby achieving mass production of carbon carriers while minimizing the generation of hazardous waste.

[0053] In this invention, the temperature of the solvothermal reaction is 150–220°C, preferably 160–210°C, more preferably 180–200°C, and most preferably 180°C, and the time is 18–24 h, preferably 20–22 h.

[0054] In this invention, gallium salt and zinc salt generate a zinc-gallium complex with a special morphology during a solvothermal reaction, which serves as an in-situ template agent for carbon precursor synthesis.

[0055] In this invention, the calcination temperature is 500–1200°C, preferably 600–1100°C, more preferably 800–1000°C, and the time is 2–4 hours, preferably 3 hours.

[0056] In this invention, gallium salts, zinc salts, amine compounds and water are mixed in a certain ratio to undergo a solvothermal reaction to generate a template agent with a specific morphology. During the in-situ synthesis process, carbon precursors are hydrolyzed, condensed and carbonized into chains to form carbon materials with a specific morphology on the template agent.

[0057] In this invention, the inert gas includes one or more of nitrogen, helium, and argon, preferably one or more of nitrogen and helium, and more preferably nitrogen.

[0058] In this invention, the acid washing involves dissolving the product obtained from calcination in a dilute hydrochloric acid solution and stirring for 2 to 4 hours, preferably 3 hours. The concentration of the dilute hydrochloric acid solution is 10 to 30 wt%, preferably 20 wt%.

[0059] The present invention also provides nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material prepared by the above preparation method. Each carbon sphere is composed of multiple carbon nanosheets stacked in an orderly manner. The diameter of the microsphere carbon material is 1-4 μm and the thickness of the nanosheets is 10-60 nm.

[0060] This invention also provides the application of the Pd(OH)2 / C catalyst prepared using the above-mentioned microsphere carbon material as a support in the debenzylation of hydrogen.

[0061] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0062] Example 1

[0063] Weigh 0.6 mmol of zinc acetate, 1 mmol of gallium nitrate, and 0.9 g of glucose and dissolve them in a mixed solution of 10 mL of deionized water and 5 mL of ethylenediamine. Stir thoroughly and transfer the homogeneous suspension to a polytetrafluoroethylene liner. Place the liner in a stainless steel autoclave and hydrothermally heat it at 180 °C for 24 h. Filter to obtain a brown solid. Place the brown solid in a tube furnace and calcine it at 800 °C for 2 h. After cooling to room temperature, remove the template agent with 20 wt% dilute hydrochloric acid. Wash thoroughly with deionized water and dry to obtain sample #1.

[0064] The carbon material in sample #1 has a diameter of 2–3 μm. Each carbon sphere is composed of multiple carbon nanosheets with a thickness of 25–35 nm stacked in an orderly manner, exhibiting abundant mesoporous and macroporous structures, and a specific surface area of ​​615 m². 2 / g. The nitrogen doping content is approximately 10.0wt%.

[0065] Comparative Example 1

[0066] Weigh 0.6 mmol of zinc acetate and 1 mmol of gallium nitrate and dissolve them in a mixed solution of 10 mL of deionized water and 5 mL of ethylenediamine. Stir thoroughly and transfer the homogeneous suspension to a polytetrafluoroethylene liner. Place the liner in a stainless steel autoclave and hydrothermally heat it at 180 °C for 24 h. Filter to obtain a white powder. Wash thoroughly with deionized water and dry to obtain sample 1-1#.

[0067] The diameter of the microspheres in the ultrathin nanosheet scaffold of sample 1-1# is 2-3 μm, and the thickness of the nanosheets is between 30-38 nm.

[0068] Water-soluble zinc salt and water-soluble gallium salt were dissolved in a mixed solution of ethylenediamine and deionized water in a specific ratio, and a white zinc gallate powder was formed by hydrothermal treatment. The morphology of the powder was mainly that of ultrathin nanosheet scaffold microspheres. After adding a carbon precursor, the carbon precursor was carbonized on the surface of zinc gallate under hydrothermal conditions to form a nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material with the same morphology (Example 1).

[0069] Scanning electron microscope images of sample 1-1# prepared in Comparative Example 1 are shown below. Figure 1 As shown, according to Figure 1 It can be seen that zinc gallate microspheres with regular morphology can be obtained in this solvent system, thus providing a template for in-situ synthesis of carbon materials.

[0070] The scanning electron microscope image of sample #1 prepared in Example 1 is shown below. Figure 2 As shown, according to Figure 2 It can be seen that the prepared sample has the same morphology as the template and the thickness of the nanosheet is between 25 and 35 nm.

[0071] The XRD pattern of sample 1-1# prepared in Comparative Example 1 is shown below. Figure 3 As shown, according to Figure 3It can be seen that zinc gallate with a regular microsphere morphology was first synthesized under the solvothermal reaction conditions, and the crystal structure of zinc gallate was confirmed by XRD spectrum.

[0072] The XRD pattern of sample #1 prepared in Example 1 is shown below. Figure 4 As shown, according to Figure 4 It can be seen that the material synthesized by this method has a relatively broad graphite diffraction peak for amorphous carbon.

[0073] Example 2:

[0074] Weigh 0.6 mmol of zinc acetate, 1 mmol of gallium nitrate, and 0.9 g of glucose, dissolve them in 7.5 mL of ethylenediamine and 7.5 mL of deionized water, stir thoroughly, transfer the homogeneous suspension to a polytetrafluoroethylene liner, and place the liner in a stainless steel autoclave for hydrothermal treatment at 180°C for 24 h. Filter to obtain a brown solid, place the brown solid in a tube furnace and calcine at 800°C for 2 h, cool to room temperature, remove the template agent with 20 wt% dilute hydrochloric acid, wash thoroughly with deionized water, and dry to obtain sample #2.

[0075] The carbon material in sample #2 has a diameter of 2.5–3.5 μm. Each carbon sphere is composed of multiple carbon nanosheets with a thickness of 40–45 nm stacked in an orderly manner, exhibiting abundant mesoporous and macroporous structures, and a specific surface area of ​​450 m². 2 / g.

[0076] Example 3

[0077] The only difference from Example 1 is that the molar ratio of zinc acetate to gallium nitrate is 0.1:1, and it is designated as sample #3.

[0078] The carbon material in sample #3 has a diameter of 4.0–5.5 μm. Each carbon sphere is composed of multiple carbon nanosheets with a thickness of 50–60 nm stacked in an orderly manner, exhibiting abundant mesoporous and macroporous structures, and a specific surface area of ​​275 m². 2 / g.

[0079] Example 4

[0080] The only difference from Example 1 is that the molar ratio of zinc acetate to gallium nitrate is 4:1, and it is designated as sample #4.

[0081] The carbon material in sample #4 has a diameter of 1.0–2.0 μm. Each carbon sphere is composed of multiple carbon nanosheets with a thickness of 20–25 nm stacked in an orderly manner, exhibiting abundant mesoporous and macroporous structures, and a specific surface area of ​​952 m². 2 / g.

[0082] Comparative Example 2

[0083] Weigh 0.6 mmol of zinc acetate, 1 mmol of gallium nitrate, and 0.9 g of glucose and dissolve them in 15 mL of deionized water. Stir thoroughly and transfer the homogeneous suspension to a polytetrafluoroethylene liner. Place the liner in a stainless steel autoclave and hydrothermally heat it at 180 °C for 24 h. Filter to obtain a brown solid. Place the brown solid in a tube furnace and calcine it at 800 °C for 2 h. After cooling to room temperature, remove the template agent with 20 wt% dilute hydrochloric acid. Wash thoroughly with deionized water and dry to obtain sample #5.

[0084] Scanning electron microscope (SEM) images of the nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material prepared in Comparative Example 2 are shown below. Figure 5 As shown, sample #5 carbon did not form regular carbon spheres during the solvothermal synthesis process without the addition of ethylenediamine. Instead, it was formed by the accumulation of a large number of disordered nanosheets with a thickness of 80–100 nm.

[0085] Comparative Example 3

[0086] Weigh out 0.6 mmol of zinc acetate, 1 mmol of gallium nitrate, and 0.9 g of glucose, dissolve them in 12 mL of ethylenediamine and 3 mL of deionized water, stir thoroughly, transfer the homogeneous suspension to a polytetrafluoroethylene liner, and place the liner in a stainless steel autoclave for hydrothermal treatment at 180°C for 24 h. Filter to obtain a brown solid, place the brown solid in a tube furnace and calcine at 800°C for 2 h, cool to room temperature, remove the template agent with 20 wt% dilute hydrochloric acid, wash thoroughly with deionized water, and dry to obtain sample #6.

[0087] Scanning electron microscope (SEM) image of the nitrogen-doped ultrathin nanosheet scaffold microsphere carbon material prepared in Comparative Example 3 is shown below. Figure 6 As shown, increasing the amount of ethylenediamine during the solvothermal synthesis of carbon sample #6 causes the collapse of some regular carbon spheres. This is because the addition of excessive ethylenediamine inhibits the dehydration, condensation, and chain formation of the carbon precursor during the reaction process.

[0088] Application examples

[0089] Using nitrogen-doped ultrathin nanosheet scaffold microsphere carbon materials obtained in Examples 1-2 and Comparative Examples 2-3 as supports, and commercial activated carbon from ACROS Organics as a control support, corresponding Pd(OH)₂ / C catalysts were prepared by deposition-precipitation method. The catalytic activity was evaluated using the hydrogenodebenzylation reaction of HBIW as a probe. The reaction conditions were as follows: 50 g HBIW, 1.0 g catalyst, 100 mL DMF, and 50 mL Ac₂O. After addition, hydrogen was purged three times, stirring was started, and the reaction was carried out at 23°C for 14 h. The hydrogen absorption curves of the catalyst samples prepared in the examples and the palladium catalyst supported on commercial activated carbon are shown in the appendix. Figure 7 ,Depend on Figure 7It can be seen that, compared with commercial activated carbon supported catalysts, the Pd(OH)2 / C-1# and Pd(OH)2 / C-2# catalysts prepared in Examples 1 and 2 exhibit excellent catalytic activity with faster hydrogen absorption rate and greater hydrogen absorption capacity in the hydrogen debenzylation reaction of HBIW.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a nitrogen-doped ultrathin nanosheet supported microsphere carbon material, characterized in that, Comprising the following steps: Step 1) mixing gallium salt, zinc salt, carbon precursor, amine compound and water, and carrying out solvothermal reaction to obtain deep red powder solid; Step 2) calcining the deep red powder solid in step 1) under inert atmosphere, and obtaining microspherical carbon material through acid washing, water washing and drying; The molar ratio of the zinc salt and the gallium salt is 0.1-4:1; The concentration of the zinc salt mixed with water is 0.01-0.4 mol / L, and the concentration of the gallium salt mixed with water is 0.01-0.4 mol / L; The volume ratio of the amine compound and water is 1:0.5-2; The concentration of the carbon precursor mixed with water is 0.01-1.0 mol / L; The gallium salt comprises one or more of gallium nitrate, gallium acetate and gallium chloride; The zinc salt comprises one or more of zinc acetate, zinc nitrate and zinc carbonate; The carbon precursor comprises glucose, maltose, fructose, sucrose or cellulose; The amine compound comprises one or more of ethylenediamine, triethylamine, triethanolamine and diethylamine; The temperature of the solvothermal reaction is 150-220℃, and the time is 18-24h; The calcination temperature is 500-1200℃, and the time is 2-4h.

2. The preparation method of the nitrogen-doped ultrathin nanosheet scaffold microspheres carbon material according to claim 1, characterized in that, The inert atmosphere comprises one or more of nitrogen, helium and argon.

3. The nitrogen-doped ultrathin nanosheet supported microsphere carbon material prepared by the preparation method of claim 1 or 2, characterized in that, Each carbon sphere is formed by ordered accumulation of multiple carbon nanosheets, the diameter of the microspherical carbon material is 1-4μm, and the thickness of the nanosheet is 10-60nm.

4. The application of the nitrogen-doped ultrathin nanosheet scaffold microspherical carbon material in claim 3 as a carrier for preparing Pd(OH)2 / C catalyst in hydrogenolysis debenzylization.

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