Preparation method of pore dynamic adjustable porous carbon based on photoisomerization

Abstract

The invention belongs to the technical field of porous carbon materials, and relates to a preparation method of pore dynamic adjustable porous carbon based on photoisomerization, which comprises the following steps: (S1) dissolving thermoplastic phenolic resin, an azobenzene derivative containing acyl chloride and a photoinitiator in a solvent inert to acyl chloride, then adding an acid-binding agent, and reacting at 40-60 DEG C; after the reaction is finished, adding a catalyst to obtain a precursor solution; (S2) forming a film from the precursor solution through a spin-coating method to obtain a film I; (S3) sequentially carrying out ultraviolet light irradiation and visible light irradiation on the film I in an inert atmosphere to trigger a photoisomerization reaction, so as to obtain a film II; and (S4) sequentially carrying out thermocuring, pre-oxidation and carbonization on the film II to obtain the porous carbon. According to the method, conventional physical activation and chemical activation processes are omitted, use of corrosive reagents such as strong acid and strong alkali is avoided, and preparation of the environment-friendly porous carbon with dynamically adjustable pores is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of porous carbon materials, and in particular relates to a method for preparing porous carbon with dynamically adjustable pores based on photoisomerization. Background Art

[0002] Porous carbon materials have been widely used in electrochemical energy storage, catalysis, adsorption separation and other fields due to their excellent specific surface area, developed pore structure and good chemical stability. However, existing methods for preparing porous carbon materials, such as physical activation, chemical activation and hard template method, all have certain limitations. Physical activation usually uses activation gases such as water vapor or CO2 to etch the surface of the carbon material under high temperature conditions to generate pores, but this process inevitably leads to a wide pore size distribution, micropores and mesopores are difficult to control independently, and once the pores are formed, they are irreversible. Although chemical activation methods (such as KOH activation) can effectively increase the specific surface area and micropore content, their preparation process requires the consumption of a large amount of strong alkali and is accompanied by severe corrosion. The subsequent neutralization and cleaning steps will produce a large amount of chemical waste liquid, which not only increases costs but also brings environmental pollution risks. Although hard template methods (such as SBA-15 and MgO template methods) can precisely control the formation of mesopores and macropores through templates, strong corrosive agents such as hydrofluoric acid are often required during the demolding process. In addition, the morphology of the template itself limits the flexible regulation of the final pore structure, making it difficult to achieve multi-level pore structure optimization from micropores to mesopores and even macropores. Therefore, the traditional preparation methods of porous carbon materials still have bottlenecks in terms of fine control of pore structure, environmental friendliness, and dynamic response characteristics, which restricts the further development of porous carbon in the fields of intelligent adsorption and controllable catalysis. Summary of the Invention

[0003] Given that the traditional preparation methods of porous carbon mentioned above still have bottlenecks in terms of fine control of pore structure, environmental friendliness and dynamic response characteristics, the present invention proposes a strategy for dynamically adjusting pores based on molecular photoisomerization reactions. By photo-induced cis-trans isomerization of azobenzene derivatives, the dynamic contraction and expansion of the phenolic resin cross-linked network is achieved, thereby forming a controllable multi-level pore structure during the carbonization process.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for preparing porous carbon with dynamically adjustable pores based on photoisomerization comprises the following steps:

[0006] (S1) dissolving a thermoplastic phenolic resin, an azobenzene derivative containing an acyl chloride, and a photoinitiator in a solvent inert to the acyl chloride, then adding an acid binding agent to form a mixed solution, and reacting at 40 to 60° C.; after the reaction is completed, adding a catalyst to obtain a precursor solution;

[0007] (S2) forming a film from the precursor solution by spin coating to obtain film I;

[0008] (S3) irradiating film I with ultraviolet light and then visible light in an inert atmosphere to trigger a photoisomerization reaction, thereby obtaining film II;

[0009] (S4) Thermally curing, pre-oxidizing, and carbonizing the membrane II in sequence to obtain porous carbon.

[0010] The azobenzene derivatives containing acyl chloride in the present invention are photoisomerizable molecules, and under different lighting conditions, the molecular configuration undergoes reversible changes. In the present invention, azobenzene derivatives containing acyl chloride are introduced into thermoplastic phenolic resin, and the acyl chloride in the azobenzene derivatives reacts with the phenolic hydroxyl group in the thermoplastic phenolic resin to form an ester group, thereby introducing the azobenzene derivatives with photoisomerization properties into the phenolic resin in the form of a covalent bond. The introduced azobenzene group acts as a photoisomerization molecular switch, and its cis / trans configuration switches to change the packing density of the phenolic molecules; by adjusting the raw material dosage ratio, regulating the lighting conditions and combining thermal curing cross-linking, pre-oxidation to fix the dynamic network structure, high-temperature carbonization to form a carbon skeleton and lock the pore structure, porous carbon with different pore sizes can be obtained, that is, dynamic regulation of the pore size is achieved. The schematic diagram of the technical route of the present invention is shown as follows. Figure 1 shown.

[0011] Furthermore, in step (S1), the amount of the azobenzene derivative containing acyl chloride is 1 to 10 wt %, preferably 5 to 7.5 wt %, of the thermoplastic phenolic resin.

[0012] Furthermore, in step (S1), the number average molecular weight of the thermoplastic phenolic resin is 300 to 1000, and the hydroxyl content is 2 wt% to 7 wt%; the azobenzene derivative containing acyl chloride is at least one of 4-phenylazobenzoyl chloride, azobenzene-4,4'-dicarbonyl chloride, azobenzene-3,3'-dicarbonyl chloride, and azobenzene-3,3',5,5'-tetracarbonyl chloride, preferably azobenzene-4,4'-dicarbonyl chloride or azobenzene-3,3'-dicarbonyl chloride; and the photoinitiator is 4,4'-bis(dimethylamino)benzophenone, and its amount is 1 to 5 wt% of the azobenzene derivative containing acyl chloride.

[0013] Furthermore, in step (S1), the solvent inert to the acyl chloride is at least one of tetrahydrofuran and dichloromethane; the acid binding agent is at least one of pyridine and triethylamine, and its amount is 0.8 to 1.5 times the mass of the azobenzene derivative containing the acyl chloride; and the concentration of the mixed solution is 15 to 25 wt%.

[0014] Furthermore, in step (S1), the reaction time is 4 to 6 hours.

[0015] Furthermore, in step (S1), the catalyst is hexamethylenetetramine, and its amount is 3-5 wt % of the thermoplastic phenolic resin. Under the catalytic action of hexamethylenetetramine, a self-crosslinking reaction occurs during the thermal curing of the phenolic resin in the subsequent step (S4).

[0016] Furthermore, in step (S2), the spin coating method is a dynamic spin coating method, and its process conditions are: the precursor solution is dynamically spin-coated on the quartz substrate at a rotation speed of 2000-3000 rpm using a spin coater at 20-25°C and a relative humidity of 40%-60%; the thickness of the film I is 150-200 μm, and the standard deviation of the coating thickness is controlled to be less than 5%. Dynamic spin coating refers to the dropwise addition of the solution after the substrate begins to rotate, and compared with static spin coating, the coating thickness and uniformity can be better controlled.

[0017] Furthermore, in step (S3), the conditions of the ultraviolet irradiation are: wavelength 365-405nm, power 50-100mW / cm 2 The conditions of the visible light irradiation are: first at a wavelength of 530 to 560 nm and a power of 60 to 100 mW / cm 2 Irradiate for 5 to 8 minutes, then irradiate at a wavelength of 530 to 560 nm and a power of 120 to 200 mW / cm 2 Under ultraviolet irradiation, the azobenzene group changes from the initial trans configuration to the cis configuration, and the molecular structure changes from linear to curved, that is, the molecule shrinks, forming smaller pores; then switch to low-power visible light irradiation (60-100mW / cm 2 ), the azobenzene group changes from cis configuration to trans configuration, and the pores expand; finally, under high power visible light irradiation (120-200 mW / cm 2 ), so that azobenzene is fully stretched to the trans configuration.

[0018] Furthermore, in step (S3), the inert atmosphere is nitrogen and / or argon.

[0019] Furthermore, in step (S4), the thermal curing conditions are 150-180°C for 4-6 hours; the pre-oxidation conditions are 250-300°C in air for 2-4 hours; and the carbonization conditions are 700-900°C in an inert atmosphere for 3-5 hours. The pre-oxidation stage fixes the dynamic network structure, and the high-temperature carbonization stage forms a carbon skeleton and locks the pore structure.

[0020] In a second aspect, the present invention further provides a porous carbon prepared by the aforementioned preparation method, wherein the average pore diameter thereof is adjustable within a range of 2 to 4 nm. By adjusting the ratio of the azobenzene derivative containing an acyl chloride to the thermoplastic novolac resin and varying the light irradiation conditions, porous carbon with different pore sizes can be obtained.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention obtains porous carbon with adjustable pore size in the range of 2 to 4 nm by adjusting the raw material dosage ratio and controlling the lighting conditions, thus solving the problem that the pore structure of traditional porous carbon is fixed and difficult to dynamically control.

[0023] 2. Compared with traditional activation or template methods, this method avoids the use of corrosive reagents such as strong acids and strong bases, eliminates the conventional physical activation and chemical activation processes, and realizes an environmentally friendly porous carbon material synthesis strategy.

[0024] 3. The entire preparation process has lower energy consumption and does not require complex post-processing steps such as multi-step activation or pickling and neutralization, which greatly simplifies the production process and reduces the cost of industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the technical route of the present invention.

[0026] Figure 2 This is the nitrogen adsorption-desorption curve of the porous carbon prepared in Example 1.

[0027] Figure 3 This is a pore size distribution diagram of the porous carbon prepared in Example 1. DETAILED DESCRIPTION

[0028] The present invention will be described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0029] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0030] Thermoplastic phenolic resin was selected from Hebei Zetian Chemical Co., Ltd., with a number average molecular weight of 650 and a hydroxyl content of 4.8 wt%.

[0031] Example 1

[0032] (S1) 100 g of thermoplastic phenolic resin was added to 450 mL of tetrahydrofuran at room temperature and stirred at 200 rpm for 50 min to fully dissolve the resin; then 5.0 g of azobenzene-4,4'-dicarbonyl chloride and 0.15 g of a photoinitiator, 4,4'-bis(dimethylamino)benzophenone, were slowly added thereto and stirred at 150 rpm for 20 min to completely dissolve the azobenzene-4,4'-dicarbonyl chloride; then 5.0 g of pyridine was added to form a mixed solution; finally, the mixture was reacted at 50° C. for 5 h. After the reaction was completed, 4 g of hexamethylenetetramine was added to obtain a precursor solution;

[0033] (S2) dynamically spin-coating the precursor solution onto an ultrasonically cleaned quartz substrate using a spin coater (2000 rpm) at 20-25° C. and a relative humidity of 40%-60% to obtain a film I with a thickness of 200±3 μm;

[0034] (S3) The film I was placed in a photoreaction chamber and a 365 nm ultraviolet light (80 mW / cm 2 ) irradiation for 10 min, then switched to 530 nm visible light (100 mW / cm 2 ) irradiated for 5 min, and finally irradiated with 530 nm high-intensity visible light (150 mW / cm 2 ) irradiated for 15 min to obtain membrane II;

[0035] (S4) Membrane II was heated to 150°C and kept warm for 4 hours for thermal curing; then the cured membrane was placed in a tubular furnace, and the temperature was increased to 250°C at a rate of 2°C / min in an air atmosphere (flow rate 50 mL / min) and kept warm for 2 hours; then the temperature was switched to a nitrogen atmosphere (flow rate 100 mL / min) and increased to 800°C at a rate of 5°C / min and kept warm for 3 hours. After the insulation was completed, the membrane was cooled to room temperature to obtain a porous carbon material.

[0036] The nitrogen adsorption-desorption curve of the porous carbon prepared in Example 1 is as follows: Figure 2 shown.

[0037] The pore size distribution ratio of the porous carbon prepared in Example 1 is shown in the figure below: Figure 3 shown.

[0038] Example 2

[0039] The rest is the same as Example 1, except that in step (S1), the amount of azobenzene-4,4'-dicarbonyl chloride used is 1.0 g.

[0040] Example 3

[0041] The rest is the same as Example 1, except that in step (S1), the amount of azobenzene-4,4'-dicarbonyl chloride used is 2.5 g.

[0042] Example 4

[0043] The rest is the same as Example 1, except that in step (S1), the amount of azobenzene-4,4'-dicarbonyl chloride used is 7.5 g.

[0044] Example 5

[0045] The rest is the same as Example 1, except that in step (S1), the amount of azobenzene-4,4'-dicarbonyl chloride used is 10.0 g.

[0046] Example 6

[0047] The rest is the same as Example 1, except that in step (S1), 4-phenylazobenzoyl chloride is used instead of azobenzene-4,4'-dicarbonyl chloride, and the reaction conditions are adjusted accordingly, specifically:

[0048] (S1) 100 g of thermoplastic phenolic resin was added to 450 mL of tetrahydrofuran at room temperature and stirred at 200 rpm for 50 min to fully dissolve the resin; then, 5.0 g of 4-phenylazobenzoyl chloride and 0.15 g of photoinitiator 4,4'-bis(dimethylamino)benzophenone were slowly added thereto and stirred at 150 rpm for 20 min to completely dissolve the azobenzene-4,4'-dicarbonyl chloride, followed by 5.0 g of pyridine to form a mixed solution; finally, the mixture was reacted at 40° C. for 6 h. After the reaction was completed, 4 g of hexamethylenetetramine was added to obtain a precursor solution;

[0049] (S2) Same as Example 1;

[0050] (S3) Same as Example 1;

[0051] (S4) Same as Example 1.

[0052] Example 7

[0053] The rest is the same as Example 1, except that in step (S1), azobenzene-3,3',5,5'-tetracarbonyl chloride is used instead of azobenzene-4,4'-dicarbonyl chloride, and the reaction conditions are adjusted accordingly, specifically as follows:

[0054] (S1) 100 g of thermoplastic phenolic resin was added to 450 mL of tetrahydrofuran at room temperature and stirred at 200 rpm for 50 min to fully dissolve the resin; then 5.0 g of azobenzene-3,3',5,5'-tetracarbonyl chloride and 0.15 g of photoinitiator 4,4'-bis(dimethylamino)benzophenone were slowly added thereto and stirred at 150 rpm for 20 min to completely dissolve the azobenzene-4,4'-dicarbonyl chloride, followed by 5.0 g of pyridine to form a mixed solution; finally, the mixture was reacted at 60° C. for 5 h, and after the reaction was completed, 4 g of hexamethylenetetramine was added to obtain a precursor solution;

[0055] (S2) Same as Example 1;

[0056] (S3) Same as Example 1;

[0057] (S4) Same as Example 1.

[0058] Example 8

[0059] The rest is the same as Example 1, except that in step (S3), the irradiation conditions of ultraviolet light and visible light are different, specifically:

[0060] (S1) Same as Example 1;

[0061] (S2) Same as Example 1;

[0062] (S3) The film I was placed in a photoreaction chamber and a 365 nm ultraviolet light (80 mW / cm 2 ) irradiation for 15 min, then switched to 530 nm visible light (100 mW / cm 2 ) irradiated for 5 min, and finally irradiated with 530 nm high-intensity visible light (150 mW / cm 2 ) irradiated for 20 min to obtain membrane II;

[0063] (S4) Same as Example 1.

[0064] Example 9

[0065] The rest is the same as Example 1, except that in step (S3), the irradiation conditions of visible light are different, specifically:

[0066] (S1) Same as Example 1;

[0067] (S2) Same as Example 1;

[0068] (S3) The film I was placed in a photoreaction chamber and a 365 nm ultraviolet light (80 mW / cm 2 ) irradiation for 10 min, then switched to 530 nm visible light (100 mW / cm 2 ) irradiated for 8 min, and finally irradiated with 530 nm high-intensity visible light (150 mW / cm 2 ) irradiated for 15 min to obtain membrane II;

[0069] (S4) Same as Example 1.

[0070] Example 10

[0071] The rest is the same as Example 1, except that only high-intensity visible light is used during visible light irradiation in step (S3), specifically:

[0072] (S1) Same as Example 1;

[0073] (S2) Same as Example 1;

[0074] (S3) The film I was placed in a photoreaction chamber and a 365 nm ultraviolet light (80 mW / cm 2 ) irradiation for 10 min, then switched to 530 nm visible light (150 mW / cm 2 ) irradiated for 20 min to obtain membrane II;

[0075] (S4) Same as Example 1.

[0076] Comparative Example 1

[0077] The rest is the same as Example 1, except that azobenzene-4,4'-dicarbonyl chloride is not added in step (S1).

[0078] Comparative Example 2

[0079] The rest is the same as Example 1, except that step (S3) is omitted, that is, the ultraviolet light irradiation and visible light irradiation are not performed.

[0080] Comparative Example 3

[0081] The rest is the same as Example 1, except that in step (S3), visible light irradiation is performed first and ultraviolet light irradiation is performed later, as follows:

[0082] (S1) Same as Example 1;

[0083] (S2) Same as Example 1;

[0084] (S3) The film I was placed in a photoreaction chamber and a 530 nm visible light (100 mW / cm 2 ) irradiated for 5 min, and then 530 nm high-intensity visible light (150 mW / cm 2 ) irradiation for 15 min, and then switched to 365 nm UV light (80 mW / cm 2 ) irradiated for 10 min to obtain membrane II;

[0085] (S4) Same as Example 1.

[0086] Testing and Analysis

[0087] The porous carbons prepared in the above examples and comparative examples were tested for specific surface area, average pore diameter and pore volume. The specific results are shown in Table 1.

[0088] Table 1 Test of specific surface area, average pore diameter and pore volume

[0089]

[0090]

[0091] As can be seen from Table 1, the present invention does not require the use of complex activation processes and corrosive reagents such as strong acids and strong bases, and achieves the preparation of environmentally friendly porous carbon. The prepared porous carbon has abundant pores with a pore diameter of 2 to 4 nm, which is mesoporous and has a specific surface area of 1000 m 2 / above.

[0092] From the data of Examples 1-5, it can be seen that the addition amount of azobenzene-4,4'-dicarbonyl chloride has an optimal range (5-7.5wt%). The porous carbon prepared in Example 1 (5wt% addition amount) and Example 4 (7.5wt% addition amount) exhibits better comprehensive performance, with a specific surface area of 1300m 2 / g, average pore diameter 3.1~3.2nm, pore volume 1.02~1.04cm 3 However, when the addition amount was increased to 10 wt% (Example 5), the pore volume decreased to 0.86 cm 3 / g, the specific surface area decreased to 1204.0m 2 / g, the possible reason is that too much azobenzene derivatives containing acyl chloride lead to too high a cross-linking density, which in turn hinders the full development of pores. From the data comparison of Examples 1, 6, and 7, it can be seen that the porous carbon prepared by monofunctional 4-phenylazobenzoyl chloride (Example 6) and tetrafunctional azobenzene-3,3',5,5'-tetracarbonyl chloride (Example 7) has relatively inferior performance, with specific surface areas of 1146.5m 2 / g and 1246.5m 2 / g, and the pore volume is 0.57cm 3 / g and 0.68cm 3 This result indicates that the bifunctional design of azobenzene derivatives can effectively promote the formation of a rich porous structure while ensuring sufficient cross-linking density, thereby optimizing material performance. The possible reasons are that the high functionality of the acyl chloride leads to excessively high cross-linking density, which in turn hinders the full development of pores; while the low functionality of the acyl chloride leads to low stability of the network structure.

[0093] The data of Examples 1, 8, and 9 reveal the importance of a phased light control strategy during light irradiation. Extending the UV irradiation time to 15 minutes (Example 8) can promote a more thorough configurational transformation of azobenzene, increasing the specific surface area to 1367.7 m 2 / g; Properly extending the low-power visible light stage to 8 minutes (Example 9) is conducive to achieving more uniform pore expansion, and 1329.3m 2These results indicate that precise control of light irradiation parameters is crucial for optimizing pore structure. The comparative example further verifies the key mechanism. The specific surface area of the porous carbon material prepared in comparative example 1 without adding azobenzene derivatives is only 463.2 m 2 / g, pore volume as low as 0.18cm 3 / g; while the performance of comparative example 2 without light irradiation treatment was even worse, with a specific surface area of only 443.2m 2 / g, pore volume as low as 0.13cm 3 / g; Comparative Example 3, which was irradiated with visible light first and then with ultraviolet light, also had poor performance, with a specific surface area of only 502.7m 2 / g, pore volume as low as 0.21cm 3 This indicates that the photoresponse characteristics of azobenzene derivatives and their configurational transformation behaviors play a decisive role in the preparation of porous carbon materials.

[0094] The data of Example 1 and Example 10 show that gradient irradiation during visible light irradiation, that is, first irradiating with low-intensity visible light and then irradiating with high-intensity visible light, is more conducive to pore expansion.

[0095] In summary, the present invention does not require a complex activation process and the use of corrosive reagents such as strong acids and strong bases. By adjusting the amount and type of azobenzene derivatives containing acyl chloride and different light irradiation conditions, porous carbon with different pore structures can be obtained, thereby achieving dynamic regulation of the pore structure of the porous carbon material.

Claims

1. A method for preparing porous carbon with dynamically adjustable pores based on photoisomerization, characterized in that: The following steps are involved: (S1) dissolving a thermoplastic phenolic resin, an azobenzene derivative containing an acyl chloride, and a photoinitiator in a solvent inert to the acyl chloride, then adding an acid binding agent to form a mixed solution, and reacting at 40 to 60° C.; after the reaction is completed, adding a catalyst to obtain a precursor solution; (S2) forming a film from the precursor solution by spin coating to obtain film I; (S3) irradiating film I with ultraviolet light and then visible light in an inert atmosphere to trigger a photoisomerization reaction, thereby obtaining film II; (S4) Thermally curing, pre-oxidizing, and carbonizing the membrane II in sequence to obtain porous carbon.

2. The preparation method according to claim 1, characterized in that In step (S1), the amount of the azobenzene derivative containing acyl chloride is 1 to 10 wt % of the thermoplastic phenolic resin.

3. The preparation method according to claim 2, characterized in that In step (S1), the amount of the azobenzene derivative containing acyl chloride is preferably 5 to 7.5 wt % of the thermoplastic phenolic resin.

4. The preparation method according to claim 1, characterized in that In step (S1), the number average molecular weight of the thermoplastic phenolic resin is 300 to 1000, and the hydroxyl content is 2 wt% to 7 wt%; the azobenzene derivative containing acyl chloride is at least one of 4-phenylazobenzoyl chloride, azobenzene-4,4'-dicarbonyl chloride, azobenzene-3,3'-dicarbonyl chloride, and azobenzene-3,3',5,5'-tetracarbonyl chloride; and the photoinitiator is 4,4'-bis(dimethylamino)benzophenone, and the amount used is 1 to 5 wt% of the azobenzene derivative containing acyl chloride.

5. The preparation method according to claim 4, characterized in that In step (S1), the azobenzene derivative containing acyl chloride is azobenzene-4,4'-dicarbonyl chloride or azobenzene-3,3'-dicarbonyl chloride.

6. The preparation method according to claim 1, characterized in that In step (S1), the solvent inert to the acyl chloride is at least one of tetrahydrofuran and dichloromethane; the acid binding agent is at least one of pyridine and triethylamine, and its amount is 0.8 to 1.5 times the mass of the azobenzene derivative containing the acyl chloride; the concentration of the mixed solution is 15 to 25 wt%; and / or The reaction time is 4 to 6 hours; and / or The catalyst is hexamethylenetetramine, and its usage is 3-5 wt% of the thermoplastic phenolic resin.

7. The preparation method according to claim 1, characterized in that In step (S2), the spin coating method is a dynamic spin coating method, and its process conditions are: 20-25°C, relative humidity 40%-60%, the precursor solution is dynamically spin-coated on the quartz substrate through a spin coater at a rotation speed of 2000-3000 rpm; the thickness of the film I is 150-200 μm, and the standard deviation of the coating thickness is controlled below 5%.

8. The preparation method according to claim 1, characterized in that In step (S3), the conditions of the ultraviolet irradiation are: wavelength 365-405nm, power 50-100mW / cm 2 The conditions of the visible light irradiation are: first at a wavelength of 530 to 560 nm and a power of 60 to 100 mW / cm 2 Irradiate for 5 to 8 minutes, then irradiate at a wavelength of 530 to 560 nm and a power of 120 to 200 mW / cm 2 Irradiate for 15 to 20 minutes.

9. The preparation method according to claim 1, characterized in that In step (S4), the thermal curing conditions are curing at 150-180°C for 4-6 hours; the pre-oxidation conditions are: keeping warm at 250-300°C in an air atmosphere for 2-4 hours; and the carbonization conditions are: keeping warm at 700-900°C in an inert atmosphere for 3-5 hours.

10. A porous carbon, characterized in that: The nanostructured ...

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