A sulfonic acid-functionalized porphyrin zr-based mof material, preparation method and applications thereof

Abstract

The application provides a preparation method and application of a sulfonic acid functionalized porphyrin Zr-based metal organic framework material, and the sulfonic acid functionalized porphyrin Zr-based metal organic framework photocatalyst is prepared by the following steps: synthesizing F-TCPP-Me by reacting 3-fluoro-4-formyl benzoic acid methyl ester with pyrrole in propionic acid, then replacing and hydrolyzing by sodium hydrosulfide, and then purifying by column chromatography to obtain a mercapto porphyrin ligand SH-TCPP; adding a certain amount of hydrogen peroxide in a solvent thermal method to obtain SO3H-MOF-525; and then adding CuCl2 in DMF to heat the MOF to introduce Cu into the porphyrin ring to obtain the sulfonic acid functionalized porphyrin Zr-based metal organic framework photocatalyst. The sulfonic acid group on the 2nd position of the porphyrin benzene ring is relatively close to the Cu catalytic center at the center of the porphyrin ring, the hydrophilicity of the sulfonic acid group improves the hydrophilic microenvironment of the catalytic center, the reaction substrate of the photocatalytic hydrogen evolution can be more quickly contacted with the catalytic center, and therefore the reaction activity of the photocatalytic hydrogen evolution is improved. The sulfonic acid hydrophilic adjustment function and the function of selecting different metals as the active center to achieve different catalytic purposes make the sulfonic acid functionalized porphyrin Zr-based metal organic framework photocatalyst have a wide application prospect in catalysis.

Description

Technical Field

[0001] This invention relates to the fields of organic ligand synthesis, functional material preparation technology and energy applications, specifically to the preparation method of Cu-SO3H-MOF-525 photocatalytic material and its application in photocatalytic hydrogen evolution. Background Technology

[0002] With the increasing severity of the global energy crisis and environmental pollution, the development of clean and renewable energy technologies has become a research hotspot. Photocatalytic water splitting for hydrogen evolution can convert solar energy into hydrogen energy, representing a promising energy conversion pathway. Among numerous photocatalytic materials, metal-organic frameworks (MOFs) have attracted widespread attention in the field of photocatalytic hydrogen evolution due to their advantages such as tunable structure, high specific surface area, and abundant active sites. In particular, porphyrin-based Zr-MOFs (such as MOF-525 and PCN-222) exhibit excellent potential photocatalytic performance due to the good light-harvesting ability of porphyrin ligands combined with the stability of Zr-oxo clusters. However, existing porphyrin Zr-MOFs still face some challenges in photocatalytic hydrogen evolution applications: on the one hand, the microenvironment around the metal active sites at the center of the porphyrin ring is mostly hydrophobic, which is not conducive to the contact between water molecules and the catalytic center, resulting in limited mass transfer of the reaction substrate; on the other hand, the separation efficiency of photogenerated electron-hole pairs needs to be improved, and there is a lack of an effective hydrogen bond network to stabilize reaction intermediates. These factors limit the photocatalytic hydrogen evolution efficiency of the materials.

[0003] To address the aforementioned problems, this invention provides a sulfonic acid-functionalized porphyrin Zr-MOF photocatalyst. By introducing a sulfonic acid group (-SO3H) at the 2-position of the porphyrin benzene ring, the strong hydrophilicity and hydrogen bond donor ability of the sulfonic acid group significantly improve the hydrophilic microenvironment around the catalytic center (such as transition metal ions like Cu), promoting the rapid diffusion of water molecules to the active site. Simultaneously, it modulates the hydrogen bond network within the MOF channels, facilitating proton transfer and hydrogen generation. Experiments show that this sulfonic acid functionalization strategy effectively improves the photocatalytic hydrogen evolution reaction activity, providing a new approach for designing highly efficient MOF photocatalysts. Summary of the Invention

[0004] Based on this, the present invention provides a sulfonic acid-functionalized porphyrin Zr-based MOF material, which is synthesized by reacting methyl 3-fluoro-4-formylbenzoate with pyrrole to form F-TCPP-Me; then, after substitution with sodium hydrosulfide and hydrolysis, the ligand SH-TCPP is obtained. During the solvothermal preparation process, hydroxyl groups are added with hydrogen peroxide to obtain SO3H-MOF-525. Finally, SO3H-MOF-525 and a transition metal ion source are heated in DMF to introduce the transition metal ions into the porphyrin ring as hydrogen evolution catalytic sites, yielding a sulfonic acid-functionalized porphyrin Zr-based metal-organic framework photocatalyst (M-SO3H-MOF-525). In this material, M is anchored in the porphyrin ring. The addition of M not only provides a hydrogen evolution active site but also improves the carrier separation efficiency of the material. Simultaneously, the presence of the sulfonic acid group significantly enhances the hydrophilic environment of the active site M, thereby enhancing the photocatalytic activity.

[0005] The acid-functionalized porphyrin Zr-based MOF material comprises: The metal-organic framework is formed by zirconium ions and sulfonic acid-functionalized porphyrin ligands linked by coordination bonds; The catalytic active center is supported on the metal-organic framework host; In this embodiment, the sulfonic acid group -SO3H in the sulfonic acid-functionalized porphyrin ligand is spatially adjacent to the catalytic active center, thereby improving the hydrophilic microenvironment of the catalytic active center.

[0006] The catalytic active center is a transition metal ion, preferably copper ion, iron ion, cobalt ion, nickel ion or zinc ion, more preferably copper ion, and the catalytic active center is located at the porphyrin ring center of the sulfonic acid-functionalized porphyrin ligand; the sulfonic acid-functionalized porphyrin ligand is tetrakis(2-sulfonyl-4-carboxyphenyl)porphyrin or a derivative thereof.

[0007] The preparation method of the sulfonate-functionalized porphyrin Zr-based MOF material includes the following steps: (1) A fluorinated aromatic aldehyde derivative is reacted with pyrrole under acid catalysis to generate a fluorinated porphyrin precursor; (2) The fluorinated porphyrin precursor obtained in step (1) is reacted with sodium hydrosulfide to replace the fluorine atom with a thiol group, and then hydrolyzed and purified to obtain the thiol-functionalized porphyrin ligand SH-TCPP. (3) The thiol-functionalized porphyrin ligand is mixed with zirconium salt in a solvent and subjected to a solvothermal reaction in the presence of an oxidant to oxidize the thiol group in situ to a sulfonic acid group, thereby forming a sulfonic acid-functionalized metal-organic framework precursor. (4) The precursor obtained in step (2) is brought into contact with a source containing catalytically active metal ions, so that the catalytically active metal ions are loaded in the precursor, thereby obtaining the sulfonic acid functionalized metal-organic framework material.

[0008] The fluorinated aromatic aldehyde derivative mentioned in step (1) is methyl 3-fluoro-4-carboxymethyl benzoate, the reaction temperature is 120-150 °C, and the reaction time is 0.5-2 h.

[0009] In step (2), the reaction temperature is 70-150 ℃ and the reaction time is 1-5 days; The alkali used in the hydrolysis step is a 2 M potassium hydroxide or sodium hydroxide solution, and the reflux reaction time is 6-24 h.

[0010] The oxidant in step (3) is 20-35% hydrogen peroxide; the zirconium salt is zirconium tetrachloride; the temperature of the solvothermal reaction is 60-150℃ and the time is 1-10 days.

[0011] The source containing catalytically active metal ions in step (4) is any one or a combination of copper salt, iron salt, cobalt salt, nickel salt, or zinc salt; the loading method is by solvothermal method or solution impregnation method; For the solvothermal method, the temperature is 60-100 ℃ and the time is 2-24 h; for the solution immersion method, the immersion time is 2-7 days.

[0012] In some preferred embodiments, the preparation method includes the following steps: (1) Synthesis of F-TCPP-Me: Methyl 3-fluoro-4-formylbenzoate and pyrrole were refluxed in propionic acid for several hours, and F-TCPP-Me was obtained by filtration and washing. (2) Synthesis of SH-TCPP: F-TCPP-Me was reacted with sodium hydrosulfide in DMF for several days, then acidified with 1M hydrochloric acid, filtered and washed with water, and the filter cake was added to a potassium hydroxide mixed solution for hydrolysis and purified by column chromatography to obtain SH-TCPP. (3) Synthesis of SO3H-MOF-525: SH-TCPP and ZrCl4 were mixed in DMF, and an appropriate amount of acetic acid regulator and hydrogen peroxide were added. SO3H-MOF-525 was synthesized by solvothermal method. (4) Synthesis of Cu-SO3H-MOF-525 material: SO3H-MOF-525 and CuCl2 were mixed in DMF and heated and stirred for several hours to obtain Cu-SO3H-MOF-525 photocatalyst.

[0013] In step (1), the concentration of methyl 3-fluoro-4-formylbenzoate is 18-160 mmol / L, the molar ratio of pyrrole to methyl 3-fluoro-4-formylbenzoate is 1:0.5 - 1:1.5, the reaction temperature is 120-150 ℃, and the reaction time is 0.5-2 h.

[0014] The concentration of F-TCPP-Me in step (2) is 0.0011 - 0.0165 mmol / L, and the molar ratio of F-TCPP-Me to sodium hydrosulfide is 1:4 - 1:10; the heating temperature is 70-150 ℃, and the reaction time is 1-5 days.

[0015] The reflux reaction time for the potassium hydroxide solution hydrolysis is 6-24 h.

[0016] In step (3), the concentration of DMF solution for SH-TCPP is 0.54 - 4.4 mmol / L, the mass ratio of ZrCl4 to SH-TCPP is 1:2 - 2:1, the volume ratio of acetic acid to DMF is 1:1.7 - 1:20, and the volume ratio of 30% hydrogen peroxide to acetic acid is 1:20000 - 1:150000; the reaction is carried out at 70 °C for 2-5 days.

[0017] In step (4), the concentration of SO3H-MOF-525 suspension is 200-10000 mg / L, the mass ratio of CuCl2 to SO3H-MOF-525 is 1:0.1-1:2.5, the heating temperature is 60-100 ℃, and the time is 2-24 h.

[0018] The 1H NMR spectrum and high-resolution mass spectra of the mercaptoporphyrin ligand SH-TCPP in the Cu-SO3H-MOF-525 material prepared by the aforementioned method are shown in the attached figure. Figure 1 Appendix Figure 2 The XRD data and infrared spectrum of the Cu-SO3H-MOF-525 photocatalyst material are shown in the attached figure. Figure 3 Appendix Figure 4 As shown.

[0019] Another technical solution of the present invention is the application of the sulfonic acid functionalized porphyrin Zr-based MOF material or the sulfonic acid functionalized porphyrin Zr-based MOF material prepared by the method in photocatalytic hydrogen evolution.

[0020] The photocatalytic hydrogen evolution is carried out under light conditions in the presence of a sacrificial agent and / or a photosensitizer.

[0021] The sacrificial agent is triethanolamine; the photosensitizer is eosin Y.

[0022] In some preferred embodiments, the Zhongjiao Jinyuan photocatalytic activity evaluation device is used as the hydrogen evolution reaction analysis device, with a 300 W xenon lamp as the light source and an AM 1.5 filter simulating sunlight irradiation. The prepared composite material is dispersed in a reactor containing a mixed solution of water and triethanolamine to carry out the photocatalytic hydrogen evolution reaction. The reactor contains eosin Y as a photosensitizer, and the hydrogen evolution performance is tested under light irradiation.

[0023] The triethanolamine content is 5-30%, the catalyst dosage is 10-30 mg, and the eosin dosage is 20-60 mg.

[0024] The beneficial effects of this invention are as follows: (1) This invention synthesizes medium-tetra(2-mercapto-4-carboxyphenyl)porphyrin for the first time. First, F-TCPP-Me is synthesized by refluxing methyl 3-fluoro-4-formylbenzoate and pyrrole in propionic acid. Then, it is replaced with sodium hydrosulfide and hydrolyzed to obtain the ligand SH-TCPP. This ligand can anchor a metal single atom in the porphyrin ring as a catalytic active center. The position of the mercapto group is close to the active center. After oxidation, a highly hydrophilic sulfonic acid group can be obtained, thereby improving the hydrophilicity of the microenvironment near the active center.

[0025] (2) SO3H-MOF-525 was synthesized by hydrothermal reaction of SH-TCPP with ZrCl4 and a small amount of hydrogen peroxide. Then, M (Cu) was anchored into the porphyrin ring by heating with a transition metal salt solution (CuCl2 as an example) to obtain the M-SO3H-MOF-525 (Cu-SO3H-MOF-525 as an example) photocatalyst. After oxidation and oxidation, the mercapto group forms a sulfonic acid group. Because its position is at position 2 of the benzene ring, close to the active neutral point, this high hydrophilicity makes it easier for the active center to contact the hydrogen evolution reaction substrate (water). The sulfonic acid group acts as a water-trapping group, accelerating the hydrogen evolution rate. Furthermore, the framework structure formed by MOF makes the active sites of M (Cu) in the ligand highly dispersed, which is more conducive to the catalytic reaction. At the same time, the presence of the sulfonic acid group and copper single atoms improves the separation of charge carriers.

[0026] (3) The M-SO3H-MOF-525 (taking Cu-SO3H-MOF-525 as an example) photocatalyst prepared in this invention uses the first synthesized ligand SH-TCPP. The M-SO3H-MOF-525 (taking Cu-SO3H-MOF-525 as an example) photocatalyst has excellent performance in photocatalytic hydrogen evolution. At the same time, the ligand has the function of anchoring different catalytic metals and improving the hydrophilicity of the active center, which can realize more potential catalytic applications. Attached Figure Description

[0027] Figure 1 This is the 1H NMR spectrum of Cu-SH-TCPP.

[0028] Figure 2 This is a high-resolution mass spectrum of Cu-SH-TCPP.

[0029] Figure 3 The image shows the X-ray powder diffraction pattern of Cu-SO3H-MOF-525.

[0030] Figure 4 The image shows the infrared spectrum of Cu-SO3H-MOF-525.

[0031] Figure 5 The graph shows the photocatalytic hydrogen evolution performance of Cu-SO3H-MOF-525 and the original MOF (Cu-MOF-525). Detailed Implementation

[0032] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific implementation examples and accompanying drawings. However, the implementation examples given are not intended to limit the present invention.

[0033] Unless otherwise specified, the experimental and detection methods described in the following implementation examples are all conventional methods; unless otherwise specified, the reagents and materials described are all commercially available.

[0034] Example 1 (1) Synthesis of F-TCPP-Me: 1 g of methyl 3-fluoro-4-formylbenzoate and 0.6 mL of pyrrole were heated to 130 °C for 1.5 hours in 100 mL of propionic acid. After filtration, F-TCPP-Me was obtained by washing with methanol. (2) Synthesis of SH-TCPP: 250 mg F-TCPP-Me and 550 mg sodium hydrosulfide were dissolved in 50 mL DMF and reacted at 90 °C for 3 days under N2 atmosphere. After acidification with 1 M hydrochloric acid, the mixture was filtered and washed with water. The product was added to a 100 mL flask, and 30 mL of THF / MeOH = 1:1 mixed solution was added to the flask. Then 15 mL of 2 M potassium hydroxide aqueous solution was added. After reflux for 12 h, THF and MeOH were removed by rotary evaporation. 100 mL of water was added and acidified with 1 M hydrochloric acid. The mixture was then filtered and dried. Finally, SH-TCPP was purified by column chromatography. (3) Synthesis of SO3H-MOF-525: 15 mg SH-TCPP, 12.5 mg ZrCl4 and 10 mL DMF were mixed in a 20 mL glass bottle, 2.5 mL acetic acid and 45 μL hydrogen peroxide were added, and the mixture was placed in a 70 °C oven for 3 days and filtered to obtain SO3H-MOF-525 powder; (4) Synthesis of Cu-SO3H-MOF-525 photocatalyst: 50 mg SO3H-MOF-525 and 30 mg CuCl2 were mixed in 20 mL DMF, heated and stirred at 90 °C for 8 hours, and then filtered and washed to obtain Cu-SO3H-MOF-525 photocatalyst.

[0035] The 1H NMR spectrum of the MOF ligand Cu-SH-TCPP prepared in Example 1 was analyzed.1 Characterization by 1H NMR and high-resolution mass spectrometry (HRMS) yielded the following results: Figure 1 and Figure 2 As shown in the ¹H NMR spectrum, in addition to the active hydrogen signals from the carboxyl and mercapto groups, hydrogen signals from three different chemical environments on the benzene ring appeared in the range of 8-8.5 ppm, with an integral value of approximately 12; a hydrogen signal from the pyrrole ring appeared at 8.9 ppm, with an integral value of approximately 8. The molecular ion peak measured by high-resolution mass spectrometry was m / z 919.06, consistent with the theoretical mass-to-charge ratio of the target ligand, indicating that the organic ligand was successfully synthesized. The catalyst was characterized by X-ray powder diffraction (PXRD), and the results are as follows. Figure 3 As shown: the diffraction peaks at 6.4°, 7.9°, 9.15°, and 11.2° can be attributed to the (022), (222), (004), and (224) crystal planes, respectively. Infrared spectrum ( Figure 4 In ), 1260 cm -1 The absorption peak at 1103 cm⁻¹ is attributed to the asymmetric stretching vibration of S=O. -1 The absorption peak at 661 cm⁻¹ is attributed to the C–S stretching vibration. -1 The absorption peak at that point is attributed to the SO stretching vibration, indicating that the catalyst was successfully prepared.

[0036] Example 2 Synthesis of Cu-MOF-525: 15 mg of copper metallized porphyrin (Cu-TCPP), 12.5 mg of ZrCl4 and 10 mL of DMF were mixed in a 20 mL glass bottle, 2.5 mL of acetic acid was added, and the mixture was placed in a 70 ℃ oven for 3 days. The mixture was then filtered to obtain Cu-MOF-525 powder without sulfonic acid groups.

[0037] The catalyst was subjected to X-ray powder diffraction, and the results are as follows: Figure 3 As shown, 6.4 degrees corresponds to the 022 crystal plane, 7.9 degrees corresponds to the 222 crystal plane, 9.15 degrees corresponds to the 004 crystal plane, and 11.2 degrees corresponds to the 224 crystal plane.

[0038] The catalyst Cu-MOF-525 was characterized by X-ray powder diffraction (PXRD), and the results are as follows: Figure 3 As shown, the diffraction peaks at 6.4°, 7.9°, 9.15° and 11.2° can be attributed to the (022), (222), (004) and (224) crystal planes, respectively, indicating that the material was successfully prepared.

[0039] Example 3 20 mg of the photocatalyst prepared in Examples 1 and 2 and 30 mg of eosin Y were added to 80 mL of 10% triethanolamine solution, ultrasonically dispersed, and then added to the reactor. A 300 W xenon lamp light source equipped with an Am1.5 filter was used to simulate sunlight to initiate the photocatalytic reaction. Infrared spectroscopy of the catalyst was performed, and the results are as follows: Figure 4 As shown, the characteristic signal of sulfonic acid groups appeared in the infrared spectrum, indicating that the addition of hydrogen peroxide during MOF synthesis successfully oxidized the thiol group to a sulfonic acid group. Furthermore, the photocatalytic hydrogen evolution performance of MOFs without sulfonic acid groups was compared. Figure 5 As shown, the results indicate that the photocatalytic hydrogen evolution performance of the sulfonic acid-functionalized porphyrin Zr-based MOF reaches 4.9 mmol / g / h, which is about 3.4 times that of the unmodified original MOF.

[0040] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention. Those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Equivalent substitutions or transformations made by those skilled in the art based on the present invention are all within the protection scope of the present invention. The protection scope of the present invention is defined by the claims.

Claims

1. A sulfonic acid-functionalized porphyrin Zr-based MOF material, characterized in that, The material comprises: The metal-organic framework is formed by zirconium ions and sulfonic acid-functionalized porphyrin ligands linked by coordination bonds; The catalytic active center is supported on the metal-organic framework host; In this embodiment, the sulfonic acid group -SO3H in the sulfonic acid-functionalized porphyrin ligand is spatially adjacent to the catalytic active center, thereby improving the hydrophilic microenvironment of the catalytic active center.

2. The sulfonate-functionalized porphyrin Zr-based MOF material according to claim 1, characterized in that, The catalytic active center is a transition metal ion, preferably copper ion, iron ion, cobalt ion, nickel ion or zinc ion, more preferably copper ion, and the catalytic active center is located at the porphyrin ring center of the sulfonic acid-functionalized porphyrin ligand; the sulfonic acid-functionalized porphyrin ligand is tetrakis(2-sulfonyl-4-carboxyphenyl)porphyrin or a derivative thereof.

3. The method for preparing sulfonate-functionalized porphyrin Zr-based MOF materials according to claim 1 or 2, characterized in that, Includes the following steps: (1) A fluorinated aromatic aldehyde derivative is reacted with pyrrole under acid catalysis to generate a fluorinated porphyrin precursor; (2) The fluorinated porphyrin precursor obtained in step (1) is reacted with sodium hydrosulfide to replace the fluorine atom with a thiol group, and then hydrolyzed and purified to obtain the thiol-functionalized porphyrin ligand. (3) The thiol-functionalized porphyrin ligand is mixed with zirconium salt in a solvent and subjected to a solvothermal reaction in the presence of an oxidant to oxidize the thiol group in situ to a sulfonic acid group, thereby forming a sulfonic acid-functionalized metal-organic framework precursor. (4) The precursor obtained in step (2) is brought into contact with a source containing catalytically active metal ions, so that the catalytically active metal ions are loaded in the precursor, thereby obtaining the sulfonic acid functionalized metal-organic framework material.

4. The method for preparing the sulfonate-functionalized porphyrin Zr-based MOF material according to claim 3, characterized in that, The fluorinated aromatic aldehyde derivative mentioned in step (1) is methyl 3-fluoro-4-carboxymethyl benzoate, the reaction temperature is 120-150 °C, and the reaction time is 0.5-2 h.

5. The method for preparing the sulfonate-functionalized porphyrin Zr-based MOF material according to claim 3, characterized in that, In step (2), the reaction temperature is 70-150 ℃ and the reaction time is 1-5 days; The alkali used in the hydrolysis step is a 2 M potassium hydroxide or sodium hydroxide solution, and the reflux reaction time is 6-24 h.

6. The method for preparing sulfonate-functionalized porphyrin Zr-based MOF materials according to claim 3, characterized in that, The oxidant in step (3) is 20-35% hydrogen peroxide; the zirconium salt is zirconium tetrachloride; the temperature of the solvothermal reaction is 60-150℃ and the time is 1-10 days.

7. The method for preparing sulfonate-functionalized porphyrin Zr-based MOF materials according to claim 3, characterized in that, The source containing catalytically active metal ions in step (4) is any one or a combination of copper salt, iron salt, cobalt salt, nickel salt, or zinc salt; the loading method is by solvothermal method or solution impregnation method; When using the solvothermal method, the temperature is 60-100 ℃ and the time is 2-24 h; When using the solution immersion method, immerse for 2-7 days.

8. The application of the sulfonic acid-functionalized porphyrin Zr-based MOF material according to any one of claims 1-7 or the sulfonic acid-functionalized porphyrin Zr-based MOF material prepared by the method according to any one of claims 3-7 in photocatalytic hydrogen evolution.

9. The application according to claim 6, characterized in that, The photocatalytic hydrogen evolution is carried out under light conditions in the presence of a sacrificial agent and / or a photosensitizer.

10. The application according to claim 9, characterized in that, The sacrificial agent is triethanolamine; the photosensitizer is eosin Y.

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