Metalloporphyrin acylhydrazone-carbon nanotube gel and preparation method thereof

Abstract

The application discloses a metal porphyrin acylhydrazone-carbon nanotube gel and a preparation method thereof. The metal porphyrin acylhydrazone-carbon nanotube gel takes a metalized porphyrin compound containing four hydrazide groups, a compound containing at least two aldehyde groups and amino-functionalized carbon nanotubes as raw materials, and the three are covalently bonded to form a stable three-dimensional network structure with high catalytic activity and high selectivity, so that the prepared electrolytic seawater hydrogen anode catalyst has high activity, high oxygen evolution selectivity and stability simultaneously.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis, and particularly relates to a metal porphyrin hydrazone-carbon nanotube gel and its preparation method. Background Technology

[0002] With the increasing urgency of global demand for clean energy, hydrogen production through water electrolysis using renewable energy is considered a key technological pathway to achieving carbon neutrality. Seawater accounts for over 97% of the Earth's water resources, and direct seawater electrolysis for hydrogen production can eliminate dependence on scarce freshwater, holding significant strategic importance. However, the complexity of the seawater system, including its high salinity, impurities, and microorganisms, poses severe challenges to the activity, selectivity, and stability of the anode catalyst in seawater electrolysis for hydrogen production. It not only needs to drive a high current density at low overpotentials to reduce energy consumption and exhibit excellent selectivity for the oxygen evolution reaction, effectively suppressing the chlorine evolution side reaction, but also must maintain structural integrity during long-term electrolysis to prevent the active components from dissolving, agglomerating, or becoming poisoned.

[0003] Currently, the mainstream anode catalysts are still mainly oxides of precious metals such as iridium and ruthenium. There are also a small number of non-precious metal-based catalysts such as transition metal oxides, hydroxides, and sulfides. They are relatively low in cost and have considerable theoretical activity, but they often face the dilemma of poor selectivity, high overpotential, and poor stability in harsh seawater environments.

[0004] Therefore, developing anode catalysts for hydrogen production from seawater using non-precious metals that combine high activity, high oxygen evolution selectivity, and stability is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of the existing technology, a metalloporphyrin hydrazone-carbon nanotube gel and its preparation method are provided. The metalloporphyrin hydrazone-carbon nanotube gel uses a metallized porphyrin compound containing four hydrazide groups, a compound with at least two aldehyde groups, and aminated carbon nanotubes as raw materials. The three components are covalently bonded to construct a stable, highly catalytically active, and highly selective three-dimensional network structure, thereby enabling the prepared seawater electrolysis hydrogen production anode catalyst to simultaneously possess high activity, high oxygen evolution selectivity, and stability.

[0006] The first objective of this invention is to provide a metalloporphyrin hydrazone-carbon nanotube gel, the raw materials for which include a metallized porphyrin compound containing four acylhydrazine groups, a compound with at least two aldehyde groups, and aminated carbon nanotubes.

[0007] In this invention, firstly, under mild reaction conditions, a metallized porphyrin compound containing four hydrazide groups, a compound with at least two aldehyde groups, and aminated carbon nanotubes can form acylhydrazone / Schiff base bonds, constructing a three-dimensional network structure in the form of covalent bonds. Furthermore, the acylhydrazone bonds in the gel possess dynamic self-healing properties, automatically repairing defects such as cracks in the catalyst caused by seawater impact, thereby achieving overall catalyst stability. Secondly, the covalently bonded carbon nanotubes can construct a stable conductive framework, driving electrons to rapidly conduct from the highly dispersed metal active centers to the electrode substrate, thus obtaining a lower overpotential. Finally, the precise control of the electronic structure of the highly dispersed metal active centers, and the organic ligand environment around the porphyrin ring, can limit the large ionic radius of Cl... - While hydroxyl radicals can reach the active metal site relatively smoothly via the Grotes mechanism, selectivity in the oxygen evolution reaction can be achieved.

[0008] In some embodiments of the present invention, the molar ratio of the acylhydrazine group in the metalloporphyrin compound containing four acylhydrazine groups to the aldehyde group in the compound containing at least two aldehyde groups is 1:1 to 2, for example, it can be 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, or 1:1.9. By controlling the molar ratio of the two groups within the above range, it is beneficial to control the reaction process for preparing the gel and obtain a gel with an appropriate degree of crosslinking.

[0009] In some embodiments of the present invention, the mass of the aminated carbon nanotubes is 5-15% of the sum of the mass of the metallized porphyrin compound containing four acylhydrazine groups and the compound containing at least two aldehyde groups. By controlling the amount of carbon nanotubes within the above range, it is beneficial to simultaneously achieve good mechanical strength and construct a stable conductive network in the gel, thereby improving the stability and catalytic activity of the anode catalyst. Furthermore, it is understood that the carbon nanotubes are industrially common multi-walled carbon nanotubes.

[0010] In some embodiments of the present invention, the metal of the metallized porphyrin compound containing four acylhydrazine groups is selected from Pt(II), Pd(II), Ni(II), Ag(I), Zn(II) or Co(II).

[0011] In some embodiments of the present invention, the metallized porphyrin compound containing four acylhydrazine groups is selected from metallized 5,10,15,20-tetra(p-acylhydrazinephenyl)porphyrin.

[0012] In some embodiments of the present invention, the compound having at least two aldehyde groups is selected from at least one of glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, hexanal, heptanedialdehyde, anthracenedialdehyde, terephthalaldehyde, o-phthalaldehyde, isophthalaldehyde, 2-bromomalondialdehyde, 4-hydroxyphenylglyoxal, 2-chloromalondialdehyde, 2,3-thiophenedialdehyde, 2,5-thiophenedialdehyde, 4,4'-biphenyldialdehyde, 2-(4-pyridine)malondialdehyde, 2,6-pyridinedialdehyde, pyromellitic tricarboxaldehyde, 2,4,6-tris(4-aldehydephenyl)-1,3,5-triazine, tetra-(4-formylphenyl)methane, 1,3,6,8-tetra(4-formaldehydephenyl)pyrene, and 1,1'-ferrocenedialdehyde.

[0013] A second objective of this invention is to provide a method for preparing the aforementioned metalloporphyrin hydrazone-carbon nanotube gel, characterized by comprising the following steps:

[0014] S1. Synthesize the metallized porphyrin compound containing four acylhydrazide groups;

[0015] S2. Dissolve the metallized porphyrin compound containing four acylhydrazide groups and the compound containing at least two aldehyde groups in an organic solvent to obtain a pre-reaction solution;

[0016] S3. After adding the aminated carbon nanotubes and catalyst to the pre-reaction solution, a gelation reaction is carried out, followed by post-treatment to obtain the metal porphyrin hydrazone-carbon nanotube gel.

[0017] In some embodiments of the present invention, the step of synthesizing the metallized porphyrin compound containing four acylhydrazine groups in S1 includes: the porphyrin compound containing four acylhydrazine groups undergoes a metallization reaction with a metal salt to obtain the metallized porphyrin compound containing four acylhydrazine groups.

[0018] In some embodiments of the present invention, the metallized porphyrin compound containing four acylhydrazine groups is selected from 5,10,15,20-tetra(p-acylhydrazinephenyl)porphyrin.

[0019] In some embodiments of the present invention, the metal salt is selected from at least one of metal acetate salts and hydrated metal acetate salts.

[0020] In some embodiments of the present invention, the temperature of the metallization reaction is 80~120°C.

[0021] In some embodiments of the present invention, the metallization reaction takes 30 min to 12 h.

[0022] In some embodiments of the present invention, the metallization reaction step is followed by a post-treatment step of filtration and washing.

[0023] In some embodiments of the present invention, the organic solvent in S2 is selected from dimethyl sulfoxide.

[0024] In some embodiments of the present invention, in the pre-reaction solution described in S2, the concentrations of the porphyrin compound containing four acylhydrazine groups and the compound containing at least two aldehyde groups are independently 0.03~0.06 mol / L.

[0025] In some embodiments of the present invention, the catalyst in S3 is selected from acetic acid.

[0026] In some embodiments of the present invention, the temperature of the gelation reaction in S3 is 25~80°C.

[0027] In some embodiments of the present invention, the gelation reaction in S3 takes 1 to 24 hours.

[0028] In some embodiments of the present invention, the post-processing described in S3 includes the steps of washing with DMSO, ethanol and subcritical CO2 extraction in sequence.

[0029] In some embodiments of the present invention, the subcritical CO2 extraction step is carried out in a high-pressure stainless steel solenoid extractor, with an extraction temperature of about 1±3℃, an extraction pressure of 5.8±1 MPa, and an extraction time of 20±4h.

[0030] In some embodiments of the present invention, after the subcritical CO2 extraction step, a step of slowly reducing the pressure to atmospheric pressure at room temperature is further included, preferably, reducing the pressure to atmospheric pressure within 2 to 3 hours.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) In the metal porphyrin hydrazone-carbon nanotube gel of the present invention, the raw materials include metallized porphyrin compounds with four hydrazide groups, compounds with at least two aldehyde groups, and aminated carbon nanotubes. Under mild reaction conditions, hydrazone / Schiff base bonds can be formed to construct a three-dimensional network structure in the form of covalent bonds. The hydrazone bonds in the gel have dynamic self-healing properties and can automatically repair defects such as cracks generated by the catalyst under the impact of seawater, thereby achieving the overall stability of the catalyst.

[0033] (2) In the metal porphyrin hydrazone-carbon nanotube gel of the present invention, the carbon nanotubes covalently bonded together can form a stable conductive framework, which can drive electrons to be rapidly conducted from highly dispersed metal active centers to the electrode substrate, thereby obtaining a lower overpotential.

[0034] (3) In the metal porphyrin hydrazone-carbon nanotube gel of the present invention, the electronic structure of the highly dispersed metal active centers is precisely regulated, and the organic ligand environment around the porphyrin ring can limit the large ionic radius of Cl.- While hydroxyl radicals can reach the active metal site relatively smoothly via the Grotes mechanism, selectivity in the oxygen evolution reaction can be achieved. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0036] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0037] Example 1

[0038] This embodiment provides a metalloporphyrin hydrazone-carbon nanotube gel, the preparation steps of which include:

[0039] S1. Dissolve 1.0 mmol of 5,10,15,20-tetra(p-acylhydrazine phenyl)porphyrin THPP in 150 mL of N,N-dimethylformamide DMF, add 10 mmol of Ni(OAc)2·4H2O, react at about 120 °C for 8 h, then cool to room temperature, filter, wash, and dry to obtain the metallized porphyrin compound Ni-THPP containing four acylhydrazine groups;

[0040] S2. Dissolve 0.2 mmol Ni-THPP and 0.48 mmol glutaraldehyde in dimethyl sulfoxide to obtain a pre-reaction solution, wherein the concentration of Ni-THPP is approximately 0.03 mol / L;

[0041] S3. Add 10 wt% (relative to the sum of Ni-THPP and glutaraldehyde) of aminated multi-walled carbon nanotubes and 30 μL of DMSO solution (3 mol / L) of acetic acid to the pre-reaction solution of S2. Mix well and react at 80℃ for about 12 h to obtain an opaque gel. Let the obtained opaque gel stand at 80℃ for 24 h, cool to room temperature, and wash continuously with DMSO, changing the DMSO once a day for three days to obtain a wet gel. Then wash the wet gel with ethanol for three days in the same way. Place the solvent-exchanged gel in a 0.75 L high-pressure stainless steel solenoid extractor and extract with subcritical CO2 (l) (270 g) for 20 h at an extraction temperature of about 17℃ (pressure 5.8 MPa). After completion, slowly reduce the pressure to atmospheric pressure at room temperature (about 2-3 h) and take it out to obtain the metal porphyrin hydrazone-carbon nanotube gel.

[0042] Example 2

[0043] This embodiment provides a metalloporphyrin hydrazone-carbon nanotube gel, which differs from Example 1 only in that the 0.48 mmol glutaraldehyde in S2 of Example 1 is replaced with 0.48 mmol 1,1'-ferrocenediformaldehyde. Everything else remains the same as in Example 1.

[0044] Example 3

[0045] This embodiment provides a metalloporphyrin hydrazone-carbon nanotube gel, which differs from Example 1 only in that the 0.48 mmol glutaraldehyde in S2 of Example 1 is replaced with 0.24 mmol 1,3,6,8-tetra(4-carboxymethylphenyl)pyrene. Everything else remains the same as in Example 1.

[0046] Example 4

[0047] This embodiment provides a metalloporphyrin hydrazone-carbon nanotube gel, the preparation steps of which include:

[0048] S1. Dissolve 1.0 mmol THPP in 150 mL N,N-dimethylformamide DMF, add 10 mmol Pd(OAc)2, react at about 120 °C for 6 h, then cool to room temperature, filter, wash, and dry to obtain Pd-THPP, a metallized porphyrin compound containing four acylhydrazine groups.

[0049] S2. Dissolve 0.2 mmol Pd-THPP and 0.48 mmol 1,1'-ferrocene dicarboxaldehyde in dimethyl sulfoxide to obtain a pre-reaction solution, wherein the concentration of Pd-THPP is approximately 0.03 mol / L.

[0050] S3. Add 10 wt% (relative to the mass of Pd-THPP and 1,1'-ferrocene dicarboxaldehyde) of aminated multi-walled carbon nanotubes and 30 μL of DMSO solution (3 mol / L) of acetic acid to the pre-reaction solution of S2. Mix well and react at 80℃ for about 12 h to obtain an opaque gel. Let the obtained opaque gel stand at 80℃ for 24 h, cool to room temperature, and wash continuously with DMSO, changing the DMSO once a day for three days to obtain a wet gel. Then wash the wet gel with ethanol for three days in the same way. Place the solvent-exchanged gel in a 0.75 L high-pressure stainless steel solenoid extractor and extract with subcritical CO2 (l) (270 g) for 20 h at an extraction temperature of about 17℃ (pressure 5.8 MPa). After extraction, slowly reduce the pressure to ambient (about 2-3 h) at room temperature to obtain the metalloporphyrin hydrazone-carbon nanotube gel.

[0051] Example 5

[0052] This embodiment provides a metalloporphyrin hydrazone-carbon nanotube gel, the preparation steps of which include:

[0053] S1. Dissolve 1.0 mmol THPP in 150 mL N,N-dimethylformamide DMF, add 10 mmol Zn(OAc)2·2H2O, react at about 120 °C for 1 h, then cool to room temperature, filter, wash, and dry to obtain Zn-THPP, a metallized porphyrin compound containing four acylhydrazine groups.

[0054] S2. Dissolve 0.2 mmol Zn-THPP and 0.48 mmol 1,1'-ferrocene dicarboxaldehyde in dimethyl sulfoxide to obtain a pre-reaction solution, wherein the concentration of Zn-THPP is approximately 0.03 mol / L;

[0055] S3. Add 10 wt% (relative to the combined mass of Zn-THPP and 1,1'-ferrocene dicarboxaldehyde) of aminated multi-walled carbon nanotubes and 30 μL of DMSO solution (3 mol / L) of acetic acid to the pre-reaction solution of S2. Mix well and react at 80°C for about 12 h to obtain an opaque gel. Let the obtained opaque gel stand at 80°C for 24 h, cool to room temperature, and wash continuously with DMSO, changing the DMSO once a day for three days to obtain a wet gel. Then wash the wet gel with ethanol for three days using the same method. Place the solvent-exchanged gel in a 0.75 L high-pressure stainless steel solenoid extractor and extract with subcritical CO2 (l) (270 g) for 20 h at an extraction temperature of about 17°C (pressure 5.8 MPa). After extraction, slowly reduce the pressure to ambient (about 2-3 h) at room temperature to obtain the metalloporphyrin hydrazone-carbon nanotube gel.

[0056] Example 6

[0057] This embodiment provides a metalloporphyrin hydrazone-carbon nanotube gel, the preparation steps of which include:

[0058] S1. Dissolve 1.0 mmol THPP in 150 mL N,N-dimethylformamide DMF, add 10 mmol Co(OAc)2·4H2O, react at about 120 °C for 4 h, then cool to room temperature, filter, wash, and dry to obtain Co-THPP, a metallized porphyrin compound containing four acylhydrazine groups.

[0059] S2. Dissolve 0.2 mmol Co-THPP and 0.48 mmol 1,1'-ferrocene dicarboxaldehyde in dimethyl sulfoxide to obtain a pre-reaction solution, wherein the concentration of Co-THPP is approximately 0.03 mol / L;

[0060] S3. Add 10 wt% (relative to the combined mass of Co-THPP and 1,1'-ferrocene dicarboxaldehyde) of aminated multi-walled carbon nanotubes and 30 μL of DMSO solution (3 mol / L) of acetic acid to the pre-reaction solution of S2. Mix well and react at 80°C for about 12 h to obtain an opaque gel. Let the obtained opaque gel stand at 80°C for 24 h, cool to room temperature, and wash continuously with DMSO, changing the DMSO once a day for three days to obtain a wet gel. Then wash the wet gel with ethanol for three days using the same method. Place the solvent-exchanged gel in a 0.75 L high-pressure stainless steel solenoid extractor and extract with subcritical CO2 (l) (270 g) for 20 h at an extraction temperature of about 17°C (pressure 5.8 MPa). After extraction, slowly reduce the pressure to ambient (about 2-3 h) at room temperature to obtain the metalloporphyrin hydrazone-carbon nanotube gel.

[0061] Comparative Example 1

[0062] This comparative example provides a metalloporphyrin hydrazone gel, the preparation steps of which include:

[0063] S1. Dissolve 1.0 mmol of 5,10,15,20-tetra(p-acylhydrazine phenyl)porphyrin THPP in 150 mL of N,N-dimethylformamide DMF, add 10 mmol of Ni(OAc)2·4H2O, react at about 120 °C for 8 h, then cool to room temperature, filter, wash, and dry to obtain the metallized porphyrin compound Ni-THPP containing four acylhydrazine groups;

[0064] S2. Dissolve 0.2 mmol Ni-THPP and 0.48 mmol 1,1'-ferrocene dicarboxaldehyde in dimethyl sulfoxide to obtain a pre-reaction solution, wherein the concentration of Ni-THPP is approximately 0.03 mol / L.

[0065] S3. Add 30 μL of DMSO solution (3 mol / L) of acetic acid to the pre-reaction solution of S2, mix well, and react at 80℃ for about 12 h to obtain an opaque gel. Let the obtained opaque gel stand at 80℃ for 24 h, cool to room temperature, and wash continuously with DMSO, changing the DMSO once a day for three days to obtain a wet gel. Then wash the wet gel with ethanol for three days in the same way. Place this solvent-exchanged gel in a 0.75 L high-pressure stainless steel solenoid extractor and extract with subcritical CO2 (l) (270 g) for 20 h at an extraction temperature of about 17℃ (pressure 5.8 MPa). After completion, slowly reduce the pressure to atmospheric pressure at room temperature (about 2-3 h) and take it out to obtain the metalloporphyrin hydrazone gel.

[0066] Comparative Example 2

[0067] This comparative example provides a metalloporphyrin imine-carbon nanotube gel, the preparation steps of which include:

[0068] S1. Dissolve 1.0 mmol of 5,10,15,20-tetra(p-aminophenyl)porphyrin TAPP in 150 mL of N,N-dimethylformamide DMF, add 10 mmol of Ni(OAc)2·4H2O, react at about 120 °C for 4 h, then cool to room temperature, filter, wash, and dry to obtain the metallized porphyrin compound Ni-TAPP containing four amino groups.

[0069] S2. Dissolve 0.2 mmol Ni-TAPP and 0.48 mmol 1,1'-ferrocene dicarboxaldehyde in dimethyl sulfoxide to obtain a pre-reaction solution, wherein the concentration of Ni-TAPP is approximately 0.03 mol / L.

[0070] S3. Add 10 wt% (relative to the mass of Ni-TAPP and 1,1'-ferrocene dicarboxaldehyde) of aminated multi-walled carbon nanotubes and 30 μL of DMSO solution (3 mol / L) of acetic acid to the pre-reaction solution of S2. Mix well and react at 80°C for about 12 h to obtain an opaque gel. Let the obtained opaque gel stand at 80°C for 24 h, cool to room temperature, and wash continuously with DMSO, changing the DMSO once a day for three days to obtain a wet gel. Then wash the wet gel with ethanol for three days using the same method. Place the solvent-exchanged gel in a 0.75 L high-pressure stainless steel solenoid extractor and extract with subcritical CO2 (l) (270 g) for 20 h at an extraction temperature of about 17°C (pressure 5.8 MPa). After extraction, slowly reduce the pressure to ambient (about 2-3 h) at room temperature to obtain the metalloporphyrin imine-carbon nanotube gel.

[0071] Performance testing:

[0072] After preparing the gels of Examples 1-6 and Comparative Examples 1-2 into catalyst slurries, an electrolytic cell was built, and the following performance tests were conducted. The results are shown in Table 1 ("-" indicates that the performance was not tested).

[0073] Preparation of catalyst slurry: For Examples 1-6 and Comparative Example 2, 5 mg of the gel was mixed with 50 μL of 5 wt% Nafion and 2 mL of anhydrous ethanol, and then ultrasonically dispersed for 30 min to obtain the catalyst slurry. For Comparative Example 1, 5 mg of the gel was mixed with 0.5 mg of carbon nanotubes, 50 μL of 5 wt% Nafion, and 2 mL of anhydrous ethanol, and then ultrasonically dispersed for 30 min to obtain the catalyst slurry. Construction of electrolytic cell: 20 μL of the above catalyst slurry was coated onto a glassy carbon electrode and air-dried to obtain the working electrode. Then, using the glassy carbon electrode as the counter electrode, the saturated calomel electrode as the reference electrode, and 1.0 M KOH + seawater as the electrolyte, an electrolytic cell was constructed.

[0074] Catalyst selectivity evaluation: measured current density at 200 mA / cm² -2 The absorbance of the electrolyte at the maximum absorption peak of 500~600nm after continuous electrolysis for 100h was used as a reference, with the absorbance of the original electrolyte as a reference.

[0075] Catalyst activity assessment: measured current density up to 10 mA / cm² -2 Overpotential at time;

[0076] Catalyst stability assessment: measured current density of 200 mA / cm² -2 The maximum voltage change after 500 hours of continuous electrolysis.

[0077] Table 1: Properties of gels from Examples 1-6 and Comparative Examples 1-2

[0078]

[0079] As shown in Table 1, the metal porphyrin hydrazone-carbon nanotube gels prepared in Examples 1-6 of this invention exhibit good selectivity, catalytic activity, and stability when used as anolyte catalysts in the electrolysis of alkaline seawater.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention.

Claims

1. A metalloporphyrin hydrazone-carbon nanotube gel, characterized in that, The raw materials for preparation include metallized porphyrin compounds containing four acylhydrazine groups, compounds with at least two aldehyde groups, and aminated carbon nanotubes.

2. The metalloporphyrin hydrazone-carbon nanotube gel according to claim 1, characterized in that, The molar ratio of the acylhydrazine group in the metallized porphyrin compound containing four acylhydrazine groups to the aldehyde group in the compound containing at least two aldehyde groups is 1:1 to 2.

3. The metalloporphyrin hydrazone-carbon nanotube gel according to claim 1, characterized in that, The mass of the aminated carbon nanotubes is 5 to 15% of the sum of the mass of the metallized porphyrin compound containing four acylhydrazine groups and the compound containing at least two aldehyde groups.

4. The metalloporphyrin hydrazone-carbon nanotube gel according to claim 1, characterized in that, The metal in the metallized porphyrin compound containing four acylhydrazine groups is selected from Pt(II), Pd(II), Ni(II), Ag(I), Zn(II) or Co(II).

5. The metalloporphyrin hydrazone-carbon nanotube gel according to claim 1, characterized in that, The metallized porphyrin compound containing four acylhydrazide groups is selected from metallized 5,10,15,20-tetra(p-acylhydrazidephenyl)porphyrin.

6. The metalloporphyrin hydrazone-carbon nanotube gel according to claim 1, characterized in that, The compound having at least two aldehyde groups is selected from at least one of glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, hexanal, heptanedialdehyde, anthracenedialdehyde, terephthalaldehyde, o-phthalaldehyde, iso-phthalaldehyde, 2-bromomalondialdehyde, 4-hydroxyphenylglyoxal, 2-chloromalondialdehyde, 2,3-thiophenedialdehyde, 2,5-thiophenedialdehyde, 4,4'-biphenyldialdehyde, 2-(4-pyridine)malondialdehyde, 2,6-pyridinedialdehyde, pyromellitic tricarboxaldehyde, 2,4,6-tris(4-aldehydephenyl)-1,3,5-triazine, tetra-(4-formylphenyl)methane, 1,3,6,8-tetra(4-formaldehydephenyl)pyrene, and 1,1'-ferrocenedialdehyde.

7. The method for preparing the metalloporphyrin hydrazone-carbon nanotube gel according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Synthesize the metallized porphyrin compound containing four acylhydrazide groups; S2. Dissolve the metallized porphyrin compound containing four acylhydrazide groups and the compound containing at least two aldehyde groups in an organic solvent to obtain a pre-reaction solution; S3. Add the aminated carbon nanotubes and catalyst to the pre-reaction solution to carry out a gelation reaction, followed by post-treatment to obtain the metal porphyrin hydrazone-carbon nanotube gel.

8. The method for preparing the metalloporphyrin hydrazone-carbon nanotube gel according to claim 7, characterized in that, The organic solvent mentioned in S2 is selected from dimethyl sulfoxide.

9. The method for preparing the metalloporphyrin hydrazone-carbon nanotube gel according to claim 7, characterized in that, The gelation reaction described in S3 is carried out at a temperature of 25~80℃.

10. The method for preparing the metalloporphyrin hydrazone-carbon nanotube gel according to claim 7, characterized in that, The post-processing described in S3 includes the steps of washing with DMSO and ethanol in sequence and then extracting with subcritical CO2.

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