Method for synthesizing porphyrin-based MOLs composite material by taking lamellar oxide as self-sacrifice template

Abstract

The invention discloses a method for synthesizing a porphyrin-based MOLs composite material by taking a lamellar oxide as a self-sacrifice template, and the method specifically comprises the following steps: preparing a lamellar oxide nanosheet NS-MO, and dispersing the NS-MO in deionized water to obtain an NS-MO suspension; porphyrin ligands with different metal centers are prepared and marked as TCPP (M); the preparation method comprises the following steps: dissolving TCPP (M) in an N, N-dimethylformamide solution, carrying out ultrasonic treatment until the TCPP (M) is completely dissolved, then adding the TCPP (M) into an NS-MO turbid liquid, adding DMF and H2O, and carrying out reaction, centrifugation, washing and vacuum drying in an ultrasonic reactor to obtain the porphyrin-based MOLs composite material. The invention also discloses an application of the porphyrin-based MOLs composite material in a CO2 cycloaddition reaction. According to the porphyrin-based MOLs composite material prepared by the invention, more accessible active sites can be exposed by the porphyrin-based MOLs composite material, and the porphyrin-based MOLs composite material is in contact with substrate molecules as far as possible, so that the catalytic activity is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material preparation, and in particular relates to a method for synthesizing a porphyrin-based MOLs composite material by using a sheet oxide as a self-sacrificial template. Background Art

[0002] CO 2 On the one hand, the raw materials of this reaction are low-cost and have high atomic utilization, which conforms to the concept of green chemistry; on the other hand, cyclic carbonates are widely used in biomedicine, high-energy battery electrolytes, fine chemical intermediates and polar solvents, and are important industrial raw materials. A variety of catalysts have been reported, such as alkali metal salts, metal oxides, metal complexes, ionic liquids, etc., which can react with CO 2 The selective coupling reaction with epoxides is promoted. However, most catalytic systems are complex and have obvious defects in the catalyst surface and separation and purification, which limits their practical application. Therefore, a multiphase catalyst with fine adjustment, Lewis acid-base center, high activity and high stability is designed and developed to achieve CO under mild conditions. 2 Efficient utilization of chemical resources is very important.

[0003] The designability of MOFs catalytic sites endows them with great potential in chemical fixation of CO 2 In 2009, researchers used IRMOF-1 / TBAB as a two-component catalyst and, under relatively mild conditions (50 °C and 0.1 MPa CO 2 ) for the first time efficiently synthesized cyclic carbonates. IRMOF-3 was post-synthetically modified with methyl iodide to successfully immobilize quaternary ammonium salts within the MOF framework. Zn 4 Coordination-Unsaturated Zn in O Clusters 2+ As Lewis acid sites, quaternary ammonium salts on the ligands work together to achieve the single-component efficient catalytic synthesis of cyclic carbonates by IRMOF-3. In addition to the open metal sites, nitrogen-rich groups such as amines and triazoles are introduced into MOFs as Lewis base sites (LBS), which can improve the CO catalysis of MOFs. 2 affinity and adsorption capacity, high CO 2 The adsorption capacity and moderate catalytic active sites can effectively play a synergistic role, thus significantly improving CO 2 However, most MOFs have large blocks, a limited number of exposed active sites, and a highly symmetrical structure that results in few defects on the catalyst surface. The surface catalytic reaction kinetics are slow, and the selective adsorption of substrates is poor, which results in low overall catalytic conversion efficiency and limits its practical application in heterogeneous catalysis.

[0004] Considering unsaturated metal nodes as Lewis acid active sites, the low-dimensionalization of high-dimensional MOFs is one of the effective methods to improve catalytic active sites. Metal-organic layers (MOLs) combine the advantages of MOFs and 2D nanosheets. Based on their microstructural characteristics, through appropriate modification and modification, better performance than bulk MOFs can be obtained. A catalyst based on stacked nanosheet metal-organic framework (MOF, CASFZU-1) was prepared by a position-selective etching method, and the Cu site coordination number was precisely controlled, improving the reactivity and stability of CO 2 in cycloaddition catalytic conversion. The PC 61 BM ([6, 6]-phenyl C 61 methyl butyrate) was embedded in the CuTCPP film by a solid-phase transfer method. The prepared PC 61 BM / CuTCPP film presents a three-dimensional structure composed of two-dimensional MOF nanosheets, effectively preventing the stacking of nanosheets. Under the conditions of room temperature and 1 atm, with the PC 61 BM@CuTCPP film as the catalyst, the CO 2 conversion efficiency is one of the best among MOF-based catalysts, with a conversion rate as high as 92.4%, and the turnover frequency is 36.0 h -1 . A functionalized metal-organic layer (MTTB MOL) was first synthesized on the surface of three-dimensional (3D) PCN-222 (Co) MOF, (TTB is (4, 4', 4''-s-triazine-2,4,6-triyl-tris(benzoate))). When applied to the cycloaddition reaction, a large number of exposed acidic sites (Co 2+ , Zr 4+ ) and basic sites (−N− groups) in the MOF structural matrix show excellent cooperative catalytic performance and exhibit high catalytic activity under mild conditions. Although some literature has confirmed the advantages of metal-organic layers (MOLs) and their composites as Lewis acid centers, the research on the thickness and surface modification of metal-organic layers lacks systematicness.

[0005] Currently, porphyrin-based metal-organic layers are used as multifunctional components in the topological design of porous networks, and through a bottom-up method, including surfactant-assisted and molecular coordination coordination, they are selectively attached to the surface of the MOF layer to inhibit the anisotropic growth of the MOF, enabling layer-by-layer growth of the MOF to form an ultrathin metal-organic layer. This method has limitations such as low yield, uneven thickness / size, and complex synthesis. In addition, the metal-organic layer prepared by this method has problems such as blockage of exposed active sites, thus limiting its high catalytic activity. Summary of the Invention

[0006] The object of the present invention is to provide a method for synthesizing porphyrin-based MOLs composites using lamellar oxides as self-sacrificial templates, which solves the problems of low catalytic activity of existing MOLs composites and the use of surfactants.

[0007] Another object of the present invention is to provide the above-mentioned porphyrin-based MOLs composites.

[0008] The third object of the present invention is to provide the application of the above-mentioned porphyrin-based MOLs composites in the CO 2 cycloaddition reaction.

[0009] The technical solution adopted by the present invention is a method for synthesizing porphyrin-based MOLs composites using lamellar oxides as self-sacrificial templates, which is specifically implemented according to the following steps: Step 1, prepare lamellar oxide nanosheets NS-MO, disperse NS-MO in deionized water to obtain an NS-MO suspension; Step 2, prepare porphyrin ligands with different metal centers, denoted as TCPP(M); Step 3, dissolve TCPP(M) prepared in Step 2 in N,N-dimethylformamide solution, ultrasonicate until completely dissolved, then add it to the NS-MO suspension prepared in Step 1, add DMF and H 2 O, react the mixture in an ultrasonic reactor, centrifuge, wash, and dry under vacuum to obtain porphyrin-based MOLs composites.

[0010] The characteristics of the present invention also lie in that, In Step 1, specifically: Dissolve nitrate in deionized water to form a nitrate solution with a concentration of 0.05-0.1 mol / L; dissolve sodium hydroxide in deionized water to form an alkali solution with a concentration of 0.1-0.2 mol / L; dropwise add the alkali solution to the nitrate solution to form a suspension, continue stirring for 12-24 h, filter the solution, wash with deionized water, and dry to obtain NS-MOH; Place NS-MOH in a muffle furnace, calcine it in an air atmosphere, and naturally cool to room temperature to obtain NS-MO. Disperse NS-MO in deionized water to obtain an NS-MO suspension with a concentration of 0.1-0.2 mol / L.

[0011] The nitrate is specifically any one of Zn(NO 3 ) 2 , Cu(NO 3 ) 2 , Co(NO 3 ) 2 , Ni(NO 3 ) 2 in it.

[0012] During calcination, the heating rate is 10 - 20 °C / min, the calcination temperature is 300 - 350 °C, and the heat preservation time is 1 - 2 h.

[0013] In step 2, specifically: Under light - shielding conditions, pyrrole is added dropwise to a propionic acid solution containing methyl p - formylbenzoate, and the mixture is stirred and refluxed at 140 - 151 °C for 10 - 12 h. After cooling to room temperature, propionic acid is removed by vacuum distillation, and the precipitate is washed successively with ethanol and ethyl acetate to obtain purple crystals, denoted as TCPPCOOMe; Under light - shielding conditions, TCPPCOOMe and metal chloride are added to DMF, and the mixture is stirred and refluxed at 100 - 120 °C for 6 - 8 h. After cooling to room temperature, water is added until precipitation no longer increases. The obtained precipitate is filtered and washed, and then with CHCl 3 Purified, the solvent is evaporated to obtain a red powder, denoted as TCPPCOOMe(M); Under stirring conditions, TCPPCOOMe(M) is dissolved in a mixed solution composed of THF and MeOH; an aqueous KOH solution is added, and the mixture is stirred and refluxed at 80 - 100 °C for 8 - 12 h. After cooling to room temperature, THF and MeOH are evaporated. Additional water is added to the obtained aqueous phase until the solid is completely dissolved, and then HCl is added for acidification until no more precipitation occurs. The precipitate is filtered, washed with deionized water, and dried to obtain a purple product, denoted as TCPP(M).

[0014] The metal chloride is ZnCl 2 、CoCl 2 、NiCl 2 、CuCl 2 Any one of them.

[0015] In step 3, the reaction time is 0.5 - 2 h, and the ultrasonic frequency is 25 - 40 kHz.

[0016] The beneficial effects of the present invention are: (1) The present invention synthesizes ultrathin porphyrin - based metal - organic layer M1 - TCPP(M2) MOLs composites using ultrathin oxide nanosheets as self - sacrificial templates. The preparation method is simple to operate, has a short reaction time, and a high yield; (2) The synthesis method of the present invention can obtain ultrathin metal - organic layers with good dispersibility, uniform thickness, and a thickness of 2 - 5 nm; (3) The synthesis method of the present invention can realize the regulation of the yield of styrene carbonate prepared by the cycloaddition of CO 2 with styrene oxide through the functional regulation of the Lewis acid sites at the porphyrin center, and it can be extended to CO 2React with other epoxides and has good application prospects in the field of utilization. 2 BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Is the X-ray diffraction of the precursor ZnO prepared in the example and its standard card diagram; Figure 2 Is the precursor Co prepared in the example 3 O 4 X-ray diffraction and its standard card diagram; Figure 3 Is the X-ray diffraction of the precursor CuO prepared in the example and its standard card diagram; Figure 4 Is the X-ray diffraction of the precursor NiO prepared in the example and its standard card diagram; Figure 5 Is the atomic force microscope image of the layered ZnO prepared in the example; Figure 6 Is the height map of the layered ZnO prepared in the example; Figure 7 Is the X-ray diffraction pattern of Ni-TCPP with different ratios prepared in the example; Figure 8 Is the X-ray diffraction pattern of the composite material Zn-TCPP(M) prepared in the example; Figure 9 Is the transmission electron microscope photograph of the lamellar composite Zn-TCPP(Ni) / ZnO prepared in Example 3; Figure 10 Is the atomic force microscope image of the lamellar composite Zn-TCPP(Ni) / ZnO prepared in Example 3; Figure 11 Is the height map of the lamellar composite Zn-TCPP(Ni) / ZnO prepared in Example 3; Figure 12 Is the scanning electron microscope image of the bulk material prepared in Example 3; Figure 13 Is the transmission electron microscope image of the bulk material prepared in Example 3; Figure 14 Is the time-profile diagram of the cycloaddition reaction of the lamellar composite CO 2 ; Figure 15 Is the cycle efficiency diagram of the cycloaddition reaction of the lamellar composite CO 2 ; DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described in detail below in conjunction with the specific embodiments and the drawings.

[0019] The method for synthesizing porphyrin-based MOLs composite materials using lamellar oxides as self-sacrificing templates in the present invention is specifically implemented according to the following steps: Step 1, preparing layered oxide nanosheets; specifically: Dissolve nitrate in deionized water to form a nitrate solution with a concentration of 0.05 - 0.1 mol / L; dissolve sodium hydroxide in deionized water to form an alkali solution with a concentration of 0.1 - 0.2 mol / L; dropwise add the alkali solution to the nitrate solution to form a suspension, continue stirring for 12 - 24 h, filter the solution, wash it with deionized water, and dry it to obtain NS-MOH; The nitrate is specifically any one of Zn(NO 3 ) 2 , Cu(NO 3 ) 2 , Co(NO 3 ) 2 , Ni(NO 3 ) 2 ; Place NS-MOH in a muffle furnace, calcine it in an air atmosphere, with a heating rate of 10 - 20 °C / min, hold it at 300 - 350 °C for 1 - 2 h, and naturally cool it to room temperature to obtain NS-MO. Disperse NS-MO in deionized water to obtain an NS-MO suspension with a concentration of 0.1 - 0.2 mol / L; Step 2, preparing porphyrin ligands with different metal centers, specifically: Under light-shielded conditions, dropwise add pyrrole to a propionic acid solution containing methyl p-formylbenzoate, stir and reflux at 140 - 151 °C for 10 - 12 h. After cooling to room temperature, remove propionic acid by vacuum distillation, wash the precipitate with ethanol and ethyl acetate in sequence to obtain purple crystals, denoted as TCPPCOOMe; Under light-shielded conditions, add TCPPCOOMe and metal chloride to DMF, stir and reflux at 100 - 120 °C for 6 - 8 h. After cooling to room temperature, add water until precipitation no longer increases. Filter and wash the obtained precipitate, and then purify it with CHCl 3 , evaporate the solvent to obtain a red powder, denoted as TCPPCOOMe(M); The metal chloride is any one of ZnCl 2 , CoCl 2 , NiCl 2 , CuCl 2 ; Under stirring conditions, TCPPCOOMe (M) was dissolved in a mixed solution composed of THF and MeOH with a volume ratio of 1:1; an equal volume of aqueous KOH solution was added, and the mixture was stirred and refluxed at 80 - 100 °C for 8 - 12 h. After cooling to room temperature, THF and MeOH were removed by evaporation. Extra water was added to the resulting aqueous phase until the solid was completely dissolved, and then HCl was added for acidification until no precipitate was formed. The precipitate was filtered and washed three times with deionized water, and dried at 80 °C for 12 h to obtain a purple product, denoted as TCPP(M).

[0020] Step 3: Prepare the porphyrin-based MOLs composite material; Dissolve TCPP(M) prepared in Step 2 in N,N-dimethylformamide solution, and ultrasonicate until completely dissolved. Then add it to the NS-MO suspension prepared in Step 1, add DMF and H 2 O, and react the mixture in an ultrasonic reactor for 0.5 - 2 h with an ultrasonic frequency of 25 - 40 kHz; a uniform porphyrin-based metal-organic layer grows on the surface of the oxide. Centrifuge, wash, and dry in vacuum to obtain the porphyrin-based MOLs composite material.

[0021] The porphyrin-based MOLs composite material prepared in the present invention enables the porphyrin-based MOLs material to expose more accessible active sites and contact the substrate molecules as much as possible, thereby improving the catalytic activity.

[0022] Example 1 Preparation of layered oxide nanosheets (1) Dissolve M(NO 3 ) 2 (M = Zn 2+ , Cu 2+ , Co 2+ , Ni 2+ ) (5 mmol) in 100 mL of deionized water, and then transfer the above solution to a 200 mL volumetric flask and make up the volume to obtain solution A1; dissolve sodium hydroxide (400 mg, 10.0 mmol) in 100 mL of deionized water, and then transfer the above solution to a 200 mL volumetric flask and make up the volume to form a solution A2 with a concentration of 0.05 mol / L; (2) Dropwise add solution A2 to solution A1 to form a suspension, continue stirring overnight. The resulting precipitate was filtered, washed with deionized water, and air-dried at room temperature to obtain a sample, denoted as NS-MOH for later use; (3) The obtained material NS-MOH (5 g) was placed in a muffle furnace and calcined under an air atmosphere with a heating rate of 5 °C / min. It was held at 350 °C for 2 h and then naturally cooled to room temperature, denoted as NS-MO, and dispersed in water to obtain suspension A3; X-ray diffraction confirmed the phase structure and crystal form of the oxide (as Figures 1-4 shown), and atomic force microscopy showed that the lateral size of the ZnO nanosheets was 1.2 μm and the thickness was about 1.5 nm (as Figures 5-6 shown).

[0023] Example 2 Synthesis of porphyrin ligands with different metal centers (4) Under light-shielded conditions, in a 250 mL three-necked flask, pyrrole (5.96 mL, 0.086 mol) was added dropwise to a propionic acid solution (100 mL) containing methyl p-formylbenzoate (0.086 mol, 14.12 g). Then it was refluxed at 150 °C for 12 h. After cooling to room temperature, propionic acid was removed by vacuum distillation. The precipitate was washed successively with a large amount of ethanol and ethyl acetate to obtain purple crystals, denoted as TCPPCOOMe.

[0024] (5) Under light-shielded conditions, TCPPCOOMe (0.854 g, 1.0 mmol) and ZnCl 2 (1.75 g, 12.8 mmol) were added to 100 mL of DMF and refluxed for 8 h. After cooling to room temperature, an appropriate amount of water was added until the precipitation no longer increased. The obtained precipitate was filtered, washed, and purified with CHCl 3 . The solvent was evaporated to obtain a red powder denoted as TCPPCOOMe(Zn); (6) Similar to the synthesis of TCPPCOOMe(Zn), other metal chlorides were used instead of ZnCl 2 , and the ratio was adjusted to synthesize TCPPCOOMe(M) with different metal centers.

[0025] (7) Under stirring, TCPPCOOMe(M) (0.75 g) was dissolved in a mixed solution of THF:MeOH (v:v = 1:1), and then an equal volume of an aqueous solution of KOH (2.63 g) was added. It was refluxed for 12 h. After cooling to room temperature, THF and MeOH were removed by evaporation. Additional water was added to the obtained aqueous phase until the solid was completely dissolved. Then 1M HCl was added for acidification until no further precipitation occurred. The precipitate was filtered and washed three times with deionized water, and then dried at 80 °C for 12 h to obtain a purple product, recorded as TCPP(M).

[0026] Example 3 Synthesis of porphyrin-based metal-organic layers and their composites Taking the synthesis of Zn-TCPP(M) and its composite as an example: (8) The NS-ZO synthesized in Example 1 was dispersed in deionized water to form suspension A3; a part of ZnO in the suspension was dissolved, which played the role of a nucleation regulator and effectively hindered the anisotropic growth of MOF.

[0027] (9) H 2 TCPP (50 mg) was dissolved in N,N-dimethylformamide (10 mL) solution, ultrasonicated until completely dissolved, and then added to suspension A3. The ratio of DMF:H 2 O was adjusted to 3:1. The mixed solution was reacted in an ultrasonic reactor for 0.5 h, and a porphyrin-based metal-organic layer grew uniformly on the surface of ZnO, obtaining well-dispersed dark brown powder. After centrifugation (rotation speed 8000 - 10000 rpm, time 5 min) and washing, it was vacuum dried at 60 °C, denoted as Zn-TCPP / ZnO. The reaction time was adjusted by temperature and frequency. Different content ratios of 2D / 2D composites were obtained by adjusting the ratio of H 2 TCPP to ZnO. Figure 7 The XRD patterns of Zn-TCPP(Ni) and its Zn-TCPP(Ni) / ZnO composites are shown. The results indicate that the prepared two-dimensional Zn-TCPP(Ni) / ZnO catalyst has characteristic diffraction peaks corresponding to ZnO and Zn-TCPP(Ni). The diffraction peaks at 31.77°, 34.42°, and 36.25° correspond to the (100), (002), and (101) crystal planes of hexagonal ZnO. The diffraction peaks in the range of 5 - 20° correspond to the (110), (002), and (004) crystal planes of MOF respectively. The reduced diffraction peaks are attributed to the selective growth of MOFs.

[0028] (11) By using TCPP(M2) to replace H 2 TCPP, through simple regulation of the reaction time, the controllable preparation of metal-organic layers of Zn-TCPP(M) with different Lewis acid centers can be achieved. X-ray diffraction confirmed the successful synthesis of Zn-TCPP(M) / ZnO composites with different Lewis acid centers (as Figure 8 shown). The TEM results show that Zn-TCPP(Ni) / ZnO presents a lamellar structure ( Figure 9 shown), and the AFM results show that the prepared lamellar structure has uniform lateral dimensions and thickness (as Figures 10-11 shown).

[0029] Example 4 (12) As a comparison, when Zn 2+ was used to replace ZnO as the zinc source and mixed with TCPP(Ni), under hydrothermal conditions, layered bulk MOFs B-Zn-TCPP(Ni) were obtained. Figure 12Scanning electron microscope and transmission electron microscope images of the prepared MOFs B-Zn-TCPP(Ni) Figure 13 ); Example 5 CO 2 Reaction with epoxides to form cyclic carbonates (13) In the present invention, the series of Zn-TCPP(M) metal-organic layers prepared above are applied to catalyze the reaction of CO 2 with epoxides to form cyclic carbonates. The specific method is as follows: (14) Using the reaction of CO 2 with styrene oxide as a model reaction, the parameters of the reaction process including temperature, catalyst dosage, type of cocatalyst and catalyst were optimized. The reaction uses 2 mmol of epoxide as the substrate, 5 mol% of tetrabutylammonium bromide TBAB as the cocatalyst, and 0.5 mol% of the catalyst. At a reaction temperature of 50-70 °C, CO 2 balloon atmosphere overnight.

[0030] (15) During the reaction process, GC / MS (Agilent 7890A / MSD 5975C) and GC (Agilent Technologies 6890N)) were used to qualitatively and quantitatively analyze the target product. The obtained sampling results are the average values of three experiments. The catalytic results show that Zn-TCPP(Ni) / ZnO has the best catalytic effect. The time-yield sampling results show ( Figure 14 ) that at 50 °C, the complete conversion of styrene oxide can be achieved after reacting for 6 h.

[0031] (16) After the reaction, the catalyst can be recycled after washing, filtering and drying. After the catalyst is recycled 6 times, its catalytic results, morphology and structure are still maintained ( Figure 15 ).

[0032] (17) The substrates include propylene oxide, epichlorohydrin, allyl glycidyl ether, cyclohexene oxide, styrene oxide, phenyl glycidyl ether and phenylpropylene oxide, and NMR was used to further confirm the products.

[0033] Example 6 Application expansion (18) By regulating the amounts of ZnO and TCPP(M), the organic of functional 2D / 2D composites with different loadings can be realized, thereby expanding their application scope. For example, Zn-TCPP(Mn) / ZnO can be used as an efficient catalyst for the epoxidation of olefins. When using H 2 O 2 as the oxidant, in a mixed solvent of acetonitrile / water, at room temperature, the complete conversion of styrene can be achieved within 20 min.

Claims

1. A method for synthesizing a porphyrin-based MOLs composite material using a sheet oxide as a self-sacrificial template, characterized in that: Follow the steps below to implement it: Step 1, preparing layered oxide nanosheets NS-MO, dispersing NS-MO in deionized water to obtain NS-MO suspension; Step 2, preparing porphyrin ligands with different metal centers, denoted as TCPP(M); Step 3, dissolving the TCPP(M) prepared in step 2 in N,N-dimethylformamide solution, ultrasonicating until completely dissolved, then adding it to the NS-MO suspension prepared in step 1, adding DMF and H2O, reacting the mixture in an ultrasonic reactor, centrifuging, washing, and vacuum drying to obtain a porphyrin-based MOLs composite material.

2. The method for synthesizing porphyrin-based MOLs composite materials using sheet oxide as a self-sacrificial template as claimed in claim 1, characterized in that: In the step 1, specifically: Dissolve nitrate in deionized water to form a nitrate solution with a concentration of 0.05-0.1 mol / L; dissolve sodium hydroxide in deionized water to form an alkaline solution with a concentration of 0.1-0.2 mol / L; add the alkaline solution dropwise to the nitrate solution to form a suspension, continue stirring for 12-24 hours, filter the solution, wash with deionized water, and dry to obtain NS-MOH; NS-MOH is placed in a muffle furnace, calcined in an air atmosphere, and naturally cooled to room temperature to obtain NS-MO. NS-MO is dispersed in deionized water to obtain a NS-MO suspension with a concentration of 0.1-0.2 mol / L.

3. The method for synthesizing porphyrin-based MOLs composite materials using sheet oxide as a self-sacrificial template as claimed in claim 2, characterized in that: Specifically, the nitrate is any one of Zn(NO3)2, Cu(NO3)2, Co(NO3)2, and Ni(NO3)2.

4. The method for synthesizing porphyrin-based MOLs composite materials using sheet oxide as a self-sacrificial template as claimed in claim 2, characterized in that: During calcination, the heating rate is 10-20°C / min, the calcination temperature is 300-350°C, and the holding time is 1-2h.

5. The method for synthesizing a porphyrin-based MOLs composite material using a sheet oxide as a self-sacrificial template as claimed in claim 1, wherein in step 2, specifically: Under light-proof conditions, pyrrole was added dropwise to a propionic acid solution containing methyl paraformylbenzoate, and the mixture was stirred and refluxed at 140-151°C for 10-12 hours. After cooling to room temperature, propionic acid was removed by distillation under reduced pressure, and the precipitate was washed with ethanol and ethyl acetate in sequence to obtain purple crystals, which were recorded as TCPPCOOMe. TCPPCOOMe and metal chloride were added to DMF under light-proof conditions, and the mixture was stirred and refluxed at 100-120°C for 6-8h. After cooling to room temperature, water was added until precipitation was precipitated and the amount of precipitation did not increase. The obtained precipitate was filtered and washed, and then purified with CHCl3. The solvent was evaporated to obtain a red powder, which was recorded as TCPPCOOMe(M). Under stirring conditions, TCPPCOOMe(M) is dissolved in a mixed solution, the mixed solution is a mixture of THF and MeOH; KOH aqueous solution is added, and the mixture is stirred and refluxed at 80-100°C for 8-12 hours. After cooling to room temperature, THF and MeOH are evaporated to remove, and additional water is added to the obtained aqueous phase until the solid is completely dissolved, and then HCl is added for acidification until no precipitation is precipitated. The precipitate is filtered and washed with deionized water, and dried to obtain a purple product, which is recorded as TCPP(M).

6. The method for synthesizing a porphyrin-based MOLs composite material using a lamellar oxide as a self-sacrificial template as claimed in claim 5, wherein the metal chloride is any one of ZnCl2, CoCl2, NiCl2, and CuCl2.

7. The method for synthesizing a porphyrin-based MOLs composite material using a lamellar oxide as a self-sacrificial template as claimed in claim 1, wherein in step 3, the reaction time is 0.5-2 h and the ultrasonic frequency is 25-40 kHz.

8. A porphyrin-based MOLs composite material prepared by the method according to any one of claims 1 to 7.

9. Use of the porphyrin-based MOLs composite material prepared by the method according to any one of claims 1 to 7 in CO2 cycloaddition reaction.

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