Metalloporphyrin porous electro-catalytic material with bcu topological network structure, preparation method of metalloporphyrin porous electro-catalytic material and application of metalloporphyrin porous electro-catalytic material in electro-catalytic oxygen evolution

Abstract

The invention discloses a metalloporphyrin porous electro-catalytic material with a bcu topological network structure, a preparation method of the metalloporphyrin porous electro-catalytic material and application of the metalloporphyrin porous electro-catalytic material in electro-catalytic oxygen evolution. A quadrangular pyrenyl skeleton molecule with eight connecting nodes and a quadrangular porphyrin skeleton molecule with eight connecting nodes are adopted, an ordered and expanded double-interpenetrating three-dimensional bcu topological network framework material is obtained through [8 + 8] imine condensation, and metallization of a porphyrin unit is further realized through metal ion post-modification, so that the porphyrin unit is obtained. The metalloporphyrin porous electro-catalysis material is obtained; the material as a heterogeneous catalyst has more excellent mass transfer efficiency and more accessible catalytic sites, has a wide application prospect in the field of catalysis, and particularly has an ideal catalytic effect in an electro-catalysis oxygen evolution reaction; # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of porous materials of covalent organic frameworks (COFs), and particularly relates to a novel metal porphyrin porous electrocatalytic material with a bcu topological network structure, a preparation method thereof, and an application in electrocatalytic oxygen evolution. Background Art

[0002] Covalent Organic Frameworks (COFs) are two-dimensional or three-dimensional porous materials formed by connecting through strong covalent bonds to form a periodic network structure. They have a highly ordered pore structure and a large specific surface area, and have broad application prospects in the fields of gas adsorption, energy storage, catalysis, etc. At present, the research on COFs mainly focuses on two-dimensional materials, and the interlayer π-π stacking interaction can realize the orderly arrangement of active sites in one-dimensional pores. However, three-dimensional COFs, with their unique three-dimensional pore structure, have more excellent mass transfer efficiency and more exposed catalytic sites, showing greater potential in heterogeneous catalysis. However, due to the limitation of the skeleton molecular design, the research on three-dimensional COFs is still less.

[0003] Porphyrin is widely used in the construction of functionalized COFs due to its enzyme-like properties and excellent metal coordination ability. However, in two-dimensional porphyrin COFs, the active metal porphyrin rings are often shielded due to interlayer stacking, restricting their catalytic performance. In contrast, three-dimensional porphyrin COFs can effectively improve the accessibility of active sites due to their open network structure. However, the reported three-dimensional porphyrin COF materials are few, and the topological networks are mainly limited to pcb, pts, dia, tbo, etc. Octa-connected porphyrin-based skeleton molecules, due to their highly symmetric tetrahedral prism configuration and clear spatial orientation, have been successfully used in the construction of three-dimensional porous materials, providing the possibility for expanding the topological structure of three-dimensional porphyrin COFs.

[0004] Based on topological design, this study successfully constructed a novel three-dimensional porphyrin COF with a bcu topology by assembling octa-connected tetrahedral prism configuration pyrene-based skeleton molecules and octa-connected metal porphyrin units. This material has a highly ordered bcu topological network, a relatively high specific surface area, and excellent thermal stability, enabling it to have more excellent mass transfer efficiency and richer catalytic sites in heterogeneous catalysis, and particularly showing excellent catalytic activity in electrocatalytic oxygen evolution. Summary of the Invention

[0005] The purpose of the present invention is to provide a novel metal porphyrin porous electrocatalytic material with a bcu topological network structure, a preparation method thereof, and an application. This metal porphyrin porous electrocatalytic material has high crystallinity, a high specific surface area, and good thermal stability, has practical application prospects in electrocatalysis, and has excellent catalytic stability.

[0006] The technical solution of the present invention is as follows:

[0007] A metal porphyrin porous electrocatalytic material with a bcu topological network structure is formed by connecting the pyrene - type eight - site framework shown in formula (1) and the porphyrin - type eight - site framework shown in formula (2) in three - dimensional space; the linking group is selected from one of -C=N-, -CO - NH-, -C=N - N=C-, -C=N - NH-, -C=C-, -C=C(CN)-, and preferably -C=N-.

[0008] In at least a part of the metal porphyrin porous electrocatalytic material, each pyrene - type eight - site framework is respectively connected to 8 adjacent porphyrin - type eight - site frameworks, and each porphyrin - type eight - site framework is respectively connected to 8 adjacent pyrene - type eight - site frameworks, forming a double - interpenetrating three - dimensional bcu topological network structure.

[0009] In at least a part of the metal porphyrin porous electrocatalytic material, the molar ratio of the pyrene - type eight - site framework to the porphyrin - type eight - site framework is (0.5 - 1.5):(0.5 - 1.5), preferably 1:1.

[0010] The specific surface area of the metal porphyrin porous electrocatalytic material is 30 - 3000 m 2 / g, and the pore size is 0.6 - 6.0 nm.

[0011]

[0012] In formula (2), M = metal, selected from one or more of iron (Fe), cobalt (Co), nickel (Ni), platinum (Pt), palladium (Pd), zinc (Zn), copper (Cu).

[0013] In formula (1) and formula (2), the wavy line represents the connection site.

[0014] The metal porphyrin porous electrocatalytic material described in the present invention includes the framework unit shown in formula (3):

[0015]

[0016] In formula (3), the definition of M is the same as that in formula (2).

[0017] The preparation method of the metal porphyrin porous electrocatalytic material described in the present invention includes the following steps:

[0018] Step 1: Add the pyrene - type compound shown in formula (4), the porphyrin - type compound shown in formula (5), a catalyst, and a reaction solvent into a reaction vessel, mix them evenly, evacuate and seal, and react at 80 - 180 °C (preferably 120 °C) for 72 - 168 h (preferably 120 h) to generate a precipitate; collect the precipitate, wash and dry it to obtain a covalent organic framework compound.

[0019] Preferably, the molar ratio of the pyrene compound shown in formula (4) to the porphyrin compound shown in formula (5) is 1:1;

[0020] The catalyst is acetic acid, and it is preferably fed in the form of an aqueous solution of 6M acetic acid;

[0021] The reaction solvent is a mixed solvent of anisole and benzyl alcohol;

[0022] Preferably, the volume ratio of anisole, benzyl alcohol, and acetic acid (6M) is 5-15:5-15:1-3, and more preferably 5:5:1;

[0023] Preferably, the ratio of the volume of the reaction solvent to the total mass of the pyrene compound shown in formula (4) and the porphyrin compound shown in formula (5) is 1 mL:15-35 mg, and more preferably 1 mL:25 mg;

[0024] Specifically, the operations of washing and drying the precipitate are as follows: The precipitate is first soaked in N,N-dimethylacetamide for 12 h, repeated twice, then soaked in acetone for 12 h, repeated twice, then Soxhlet extracted with tetrahydrofuran and acetone for 48 h respectively, and then placed in a vacuum drying oven, evacuated to 20 mTorr at 80 °C, and dried for 24 h to obtain the covalent organic framework compound;

[0025] Step 2: Add the covalent organic framework compound, metal salt, and organic solvent obtained in Step 1 to a reaction vessel, mix evenly, evacuate and seal, and react at 90-150 °C (preferably 120 °C) for 12-36 h (preferably 24 h), and then separate the solid product for washing and drying to obtain the metal porphyrin porous electrocatalytic material;

[0026] The metal ion in the metal salt can be Fe 2+ 、Fe 3+ 、Co 2+ 、Co 3+ 、Ni 2+ 、Pt 2+ 、Pd 2+ 、Zn 2+ 、Cu 2+ or one or more of them;

[0027] The mass ratio of the covalent organic framework compound to the metal salt is 1:1-3, preferably 1:2;

[0028] The organic solvent is selected from one of N,N-dimethylformamide, N,N-dimethylacetamide, toluene, and acetonitrile, and preferably N,N-dimethylacetamide;

[0029] Preferably, the ratio of the volume of the organic solvent to the total mass of the covalent organic framework compound and the metal salt is 1 mL:60-120 mg, and more preferably 1 mL:90 mg;

[0030] Specifically, the operations of washing and drying the solid product are as follows: The solid product is first soaked in hot water at 80 °C for 12 h, and this is repeated three times. Then it is soaked in N,N-dimethylacetamide for 12 h, and this is repeated twice. Subsequently, it is soaked in acetone for 12 h, and this is repeated twice. It is subjected to Soxhlet extraction with tetrahydrofuran and acetone for 48 h respectively. Then it is placed in a vacuum drying oven, and the vacuum is pumped to 20 mTorr at 80 °C, and dried for 24 h to obtain the metal porphyrin porous electrocatalytic material;

[0031]

[0032] In formulas (4) and (5),

[0033] One of R1 and R2 is an aldehyde group (-CHO), and the other is an amino group (-NH2); preferably, R1 is an amino group (-NH2) and R2 is an aldehyde group (-CHO).

[0034] The metal porphyrin porous electrocatalytic material of the present invention can be used for electrocatalytic oxygen evolution reaction.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The present invention provides a design strategy for a metal porphyrin porous electrocatalytic material with a novel bcu topological network structure. By using a tetragonal prism-shaped pyrene-based skeleton molecule with eight connection nodes and a tetragonal prism-shaped porphyrin-based skeleton molecule with eight connection nodes, an ordered and extended three-dimensional bcu topological network framework compound with double interpenetration is obtained through [8 + 8] imine condensation. Further, through post-modification of metal ions, metallization of the porphyrin unit is achieved to obtain the metal porphyrin porous electrocatalytic material.

[0037] In the present invention, the three-dimensional covalent organic framework material has high crystallinity, high specific surface area and good thermal stability, making this novel three-dimensional covalent organic framework material have more excellent mass transfer efficiency and more accessible catalytic sites as a heterogeneous catalyst, and has broad application prospects in the field of catalysis, especially having ideal catalytic effects in electrocatalytic oxygen evolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 : Topological network structure diagram of the three-dimensional porphyrin-based covalent organic framework compound in Example 1 of the present invention.

[0039] Figure 2 : Schematic synthesis diagram of the three-dimensional porphyrin-based covalent organic framework compound in Example 1 of the present invention.

[0040] Figure 3 : Schematic synthesis diagram of the metal porphyrin porous electrocatalytic material synthesized by post-modifying the metal of the three-dimensional porphyrin-based covalent organic framework compound in Example 1 of the present invention.

[0041] Figure 4 : Scanning electron microscope photos of the three-dimensional porphyrin-based covalent organic framework compound (a) and the metal porphyrin porous electrocatalytic material (b) in Example 1 of the present invention.

[0042] Figure 5 : Three-dimensional spatial structure diagram of the three-dimensional porphyrin-based covalent organic framework compound in Example 1 of the present invention constructed by Materials studio software.

[0043] Figure 6 : Powder X-ray (PXRD) test spectra of the three-dimensional porphyrin-based covalent organic framework compound and the metal porphyrin porous electrocatalytic material in Example 1 of the present invention.

[0044] Figure 7 : Infrared absorption (FT-IR) spectra of the pyrene-based skeleton molecule, porphyrin-based skeleton molecule, three-dimensional porphyrin-based covalent organic framework compound, and metal porphyrin porous electrocatalytic material in Example 1 of the present invention.

[0045] Figure 8 : Nitrogen adsorption-desorption isotherm and pore size distribution diagram of the three-dimensional porphyrin-based covalent organic framework compound and the metal porphyrin porous electrocatalytic material in Example 1 of the present invention at 77K.

[0046] Figure 9 : Polarization curve diagrams of linear sweep voltammetry (LSV) of the three-dimensional porphyrin-based covalent organic framework compound, the metal porphyrin porous electrocatalytic material, and commercial RuO2 in Example 1 of the present invention. Detailed implementation manners

[0047] For a clearer understanding of the purpose, technical solution and advantages of the present invention, the following further describes the present invention in detail with specific examples and drawings. However, it should be understood that the specific examples described in this part are only for clearly explaining the features and advantages of the present invention and are not used to limit the present invention.

[0048] Example 1

[0049] (1) Synthesis of three-dimensional covalent organic framework material (referred to as PCOF-1, PCOF = porphyrin-based covalent organic framework)

[0050] Refer to Figure 2, 5',5"",5'""',5"""""(porphyrin-5,10,15,20-tetrayl)tetrakis(([1,1':3',1"-terphenyl]-4,4"-dicarbaldehyde)) (Por-8-CHO) (28.92 mg, 0.02 mmol), 5',5"",5'""',5"""""(pyrene-1,3,6,8-tetrayl)tetrakis(([1,1':3',1"-terphenyl]-4,4"-diamine)) (Py-8-NH2) (24.69 mg, 0.02 mmol), anisole (1.0 mL) and benzyl alcohol (1.0 mL) were weighed into a glass ampoule together. The solution was sonicated for 5 minutes to obtain a dark purple turbid solution. 6 M acetic acid (0.2 mL) was added as a catalyst to the glass ampoule. The glass ampoule was quickly frozen in a liquid nitrogen bath at 77 K and degassed by freeze-pump-thaw cycle three times, and then sealed. The glass ampoule was placed in an oven at 120 °C for 5 days. The purple-red solid was separated by centrifugation and soaked and washed with N,N-dimethylacetamide (2 × 10 mL) and acetone (2 × 10 mL). The obtained precipitate was filtered and then thoroughly washed with tetrahydrofuran and acetone by Soxhlet extraction for 48 h. Then the sample was transferred to a vacuum chamber and evacuated to 20 mTorr at 80 °C and dried for 24 h to obtain PCOF-1 as a brown-red powder (yield: 46.39 mg, 91%).

[0051] (2) Metal porphyrin porous electrocatalytic material (named PCOF-1@Co)

[0052] See Figure 3 , the three-dimensional porphyrin-based covalent organic framework material (60 mg) synthesized in the previous step, cobalt(II) acetate tetrahydrate (119.6 mg, 0.48 mmol) and N,N-dimethylacetamide (2.0 mL) were weighed into a glass ampoule together. The glass ampoule was quickly frozen in a liquid nitrogen bath at 77 K and degassed by freeze-pump-thaw cycle three times, and then sealed. The glass ampoule was placed in an oven at 120 °C for 24 h. The dark red solid was separated by centrifugation, washed with hot water at 80 °C (3 × 10 mL), and then immersed in N,N-dimethylacetamide to exchange solvents several times. The obtained precipitate was filtered and then thoroughly washed with tetrahydrofuran and acetone by Soxhlet extraction for 48 h. Then the sample was transferred to a vacuum chamber and evacuated to 20 mTorr at 80 °C and dried for 24 h to obtain PCOF-1@Co as a dark red powder (yield: 53.4 mg, 84.8%).

[0053] (3) Product characterization and performance testing

[0054] Scanning electron microscope (SEM) pattern, Figure 4 in (a) shows that the PCOF-1 has a uniform particle morphology of ~100 nm and is further assembled into nanoscale spheres. In contrastFigure 4 The morphology of PCOF-1@Co obtained by post-metallization of (b) metal was maintained.

[0055] See Figure 5 , the crystal structure of the three-dimensional porphyrin-based covalent organic framework was analyzed by XRD measurement and simulation. Based on the double interpenetrated bcu topological network structure, the preset structure of the three-dimensional porphyrin-based covalent organic framework was optimized for geometric energy using Materials Studio software. Refer to Figure 6 , the simulated XRD curve generated by the double interpenetrated bcu topology matched well with the experiment. The peaks obtained experimentally at 4.17°, 5.83°, 8.46°, 10.64°, 12.79°, 13.64°, 17.06°, 19.79°, 21.65°, and 23.83° 2θ corresponded to the Bragg peaks (110 / 011), (200 / 020), (220), (320), (033), (142), (044), (360), (461), and (811) of the P2 / m space group. The crystallinity of PCOF-1@Co obtained by post-metallization was maintained.

[0056] See Figure 7 , Fourier transform infrared (FT-IR) spectroscopy showed that compared with the ligands Por-8-CHO and Py-8-NH2, PCOF-1 had new absorption peaks corresponding to the characteristic stretching vibration of the C=N bond at 1623 cm -1 . In addition, the significant reduction of the C=O stretching vibration of Por-8-CHO at 1700 cm -1 confirmed the conversion of the aldehyde group. The structure of PCOF-1@Co obtained by post-metallization was maintained.

[0057] See Figure 8 , the N2 adsorption measurement at 77 K showed that this three-dimensional covalent organic framework material had a type-IV isotherm, which is characteristic of mesoporous materials, with specific surface areas of PCOF-1 (1001.6 m 2 / g) and PCOF-1@Co (892.5 m 2 / g). The pore size distributions of PCOF-1 and PCOF-1@Co calculated by non-local density functional theory (NLDFT) were mainly and , which was consistent with the proposed double interpenetrated bcu structure.

[0058] Example 2

[0059] Electrocatalytic oxygen evolution activity test

[0060] PCOF-1@Co, PCOF-1, and commercial noble metal catalyst RuO₂ were coated on carbon cloth to form electrodes (the coating method refers to Materials Chemistry Frontiers 2023, 7, 230-237), and comparisons were made by linear sweep voltammetry (LSV). Figure 9 The LSV polarization curves after current compensation are shown. The unpostmodified PCOF-1 exhibited a low anodic current density and a high overpotential. After postmodification with Co ions, the anodic current density of PCOF-1@Co increased significantly. By taking the current density of 10 mA / cm 2 as the benchmark for comparing electrocatalytic performance, PCOF-1@Co could be achieved at a lower overpotential of 295 mV, comparable to the overpotential of commercial RuO₂ (257 mV) and lower than most reported porphyrin-based covalent polymer catalysts, which is attributed to the three-dimensional framework structure promoting more excellent mass transfer efficiency and the exposure of more catalytic active sites.

[0061] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A metal porphyrin porous electrocatalytic material with a bcu topological network structure, characterized in that, It is formed by the connection of the pyrene - based eight - site skeleton shown in formula (1) and the porphyrin - based eight - site skeleton shown in formula (2) in three - dimensional space; In at least a part of the metal porphyrin porous electrocatalytic material, each pyrene - based eight - site skeleton is respectively connected to 8 adjacent porphyrin - based eight - site skeletons, and each porphyrin - based eight - site skeleton is respectively connected to 8 adjacent pyrene - based eight - site skeletons, constituting a double - interpenetrated three - dimensional bcu topological network structure; In formula (2), M = metal, selected from one or more of iron, cobalt, nickel, platinum, palladium, zinc, copper; In formula (1) and formula (2), the wavy line represents the connection site.

2. The metal porphyrin porous electrocatalytic material with a bcu topological network structure as described in claim 1, characterized in that, The connecting group for the connection of the pyrene - based eight - site skeleton shown in formula (1) and the porphyrin - based eight - site skeleton shown in formula (2) in three - dimensional space is selected from one of -C=N-, -CO - NH-, -C=N - N=C-, -C=N - NH-, -C=C-, -C=C(CN)-.

3. The metal porphyrin porous electrocatalytic material with a bcu topological network structure as described in claim 1, characterized in that, In at least a part of the metal porphyrin porous electrocatalytic material, the molar ratio of the pyrene - based eight - site skeleton to the porphyrin - based eight - site skeleton is (0.5 - 1.5):(0.5 - 1.5).

4. The metal porphyrin porous electrocatalytic material with a bcu topological network structure as described in claim 1, characterized in that, The metal porphyrin porous electrocatalytic material includes a skeleton unit shown in formula (3): In formula (3), the definition of M is the same as that in formula (2).

5. The preparation method of the metal porphyrin porous electrocatalytic material with a bcu topological network structure as described in claim 1, characterized in that, It includes the following steps: Step 1: Add the pyrene - based compound shown in formula (4), the porphyrin - based compound shown in formula (5), a catalyst, and a reaction solvent into a reaction vessel, mix them evenly, evacuate and seal, and react at 80 - 180 °C for 72 - 168 h to generate a precipitate; collect the precipitate, wash and dry it to obtain a covalent organic framework compound; The catalyst is acetic acid; The reaction solvent is a mixed solvent of anisole and benzyl alcohol; Step 2: Add the covalent organic framework compound obtained in Step 1, a metal salt, and an organic solvent into a reaction vessel, mix them evenly, evacuate and seal, and react at 90 - 150 °C for 12 - 36 h, then separate the solid product, wash and dry it to obtain the metal porphyrin porous electrocatalytic material; The metal ions in the metal salt are selected from Fe 2+ , Fe 3+ , Co 2+ , Co 3+ , Ni 2+ , Pt 2+ , Pd 2+ , Zn 2+ , Cu 2+ ; one or more of them The organic solvent is selected from one of N,N - dimethylformamide, N,N - dimethylacetamide, toluene, and acetonitrile; In formula (4) and formula (5), One of R1 and R2 is an aldehyde group, and the other is an amino group.

6. The preparation method according to claim 5, characterized in that, In Step 1, the molar ratio of the pyrene - based compound shown in formula (4) to the porphyrin - based compound shown in formula (5) is 1:

1.

7. The preparation method according to claim 5, wherein, In Step 2, the mass ratio of the covalent organic framework compound to the metal salt is 1:1 - 3.

8. The application of the metal porphyrin porous electrocatalytic material with a bcu topological network structure as described in claim 1 in the electrocatalytic oxygen evolution reaction.

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