MOF525 / TpAQ-COF II type heterogeneous tuberculosis shell structure photocatalyst
The MOF525/TpAQ-COF heterojunction photocatalyst was synthesized by covalent bridging, which solved the problems of fast carrier recombination and poor stability in traditional photocatalysts, and achieved efficient degradation of Rhodamine B and high catalyst stability.
Patent Information
- Application Number
- CN202511865586.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-02-13
AI Technical Summary
Traditional technologies are inefficient at removing synthetic dyes such as Rhodamine B from industrial wastewater, and existing photocatalysts suffer from rapid carrier recombination and poor stability.
MOF525/TpAQ-COFⅡ type heterojunction photocatalyst was synthesized by covalent bridging method. MOF525 is used as the core and TpAQ-COF is used as the shell to form a chemically bonded interface, which promotes the transport of photogenerated carriers across the interface and improves the structural stability.
The efficient degradation of Rhodamine B was achieved, with high interfacial charge transport efficiency, strong catalyst stability, and a degradation rate of 91.7%. The reaction kinetics conformed to the quasi-first-order kinetic model.
Smart Images
Figure CN121513974A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanomaterial preparation research, specifically to the application of a MOF525 / TpAQ-COF II type heterojunction core-shell structure photocatalyst in dye treatment. Background Technology
[0002] The efficient treatment of organic pollutants in industrial wastewater is a major challenge in environmental science today. With the rapid development of the textile and pharmaceutical industries, synthetic dyes, such as Rhodamine B (RhB), are widely detected in the environment. RhB is highly toxic and can induce gene mutations; its accumulation in the natural environment poses a significant threat to ecosystems. Traditional treatment technologies, such as adsorption, filtration, and ion exchange, are ineffective in removing organic pollutants due to their poor performance, complex preparation, and high operating costs. Therefore, there is a need to develop simple, efficient, and cost-effective technologies for eliminating organic pollutants in water.
[0003] In recent years, photocatalysis technology based on semiconductor materials has attracted widespread attention due to its high reaction rate, free radical reaction, reusability, non-toxicity, and low pollution. Covalent organic frameworks (COFs) are crystalline porous polymers in which organic monomers are interconnected by strong covalent bonds. They possess excellent chemical and thermal stability and flexible topological connectivity. Furthermore, COFs have tunable porosity and a large specific surface area, giving them unique properties such as a wide specific surface area and customizable pore structure. They are an important class of photocatalysts in chemisorption, gas storage, sensing, and catalysis. However, single-component photocatalysts lead to rapid recombination of charge carriers; constructing heterojunctions is an effective way to promote the separation of photogenerated charge carriers. Among them, the band arrangement of type II heterojunctions can drive photogenerated electrons and holes to migrate to different material components, thereby achieving effective spatial separation. MOF / COF hybrid materials combine the characteristics and advantages of both, and compared with MOF / COF composites linked by weak interactions, covalently linked composites offer much higher stability and superior photocatalytic performance.
[0004] Here, a novel core-shell structured MOF525 / TpAQ-COFⅡ heterojunction photocatalyst was synthesized in situ using a covalent bridging method. A Zr-MOF framework, characterized by its light-gathering ability, large specific surface area, high thermal stability, and chemical stability, was selected. MOF525 served as the core of the photocatalyst, while AQ units with strong electron-withdrawing groups were connected to Tp units via imine bonds, forming a donor-acceptor (DA) type structure, TpAQ-COF, which served as the shell. The prepared MOF / COF composite material exhibited excellent photocatalytic performance, high stability, and visible light harvesting ability. This study also characterized MT-2 and preliminarily explored the charge transfer mechanism of the MT-2Ⅱ heterojunction. Furthermore, the removal rate of RhB by MT-2 was investigated. Therefore, this work provides valuable reference for the design and construction of efficient and stable MOF / COF heterojunction systems. Summary of the Invention
[0005] This study synthesized a MOF525 / TpAQ-COFⅡ heterojunction photocatalyst in situ using a covalent bridging method. A chemically bonded interface was formed between the MOF525 core and the TpAQ-COF shell, which significantly improved the efficiency of photogenerated carrier transport across the interface and endowed the heterojunction with extremely high structural stability. The high interfacial charge transport efficiency and excellent stability enabled the efficient degradation of RhB. The specific synthesis steps are as follows:
[0006] (1) Preparation of MOF525
[0007] ZrOCl2·8H2O (105 mg, 0.32 mmol) and benzoic acid (2.70 g, 0.02 mol) were dispersed in a glass bottle containing N,N-dimethylformamide (DMF). The reactants were completely dissolved by sonication for 30 minutes and then transferred to a reactor. 4-Carboxyphenylporphyrin (H4TCPP, 47 mg, 0.06 mmol) was added to the above solution and reacted at 80 °C for 24 h. After the reaction, the precipitate was cooled to room temperature, washed three times with DMF and acetone, soaked in acetone for one day, filtered, and vacuum dried at 60 °C for 12 h to obtain a purple powder, MOF525.
[0008] (2) Preparation of TpAQ-COF
[0009] 0.0357 g of 2,6-diaminoanthraquinone (AQ) and 0.021 g of 1,3,5-trihydroxy-2,4,6-trialdehyde phenol (Tp) were added to 0.4 mL of acetic acid, 1 mL of dioxane, and 1 mL of mesitylene. The mixture was transferred to a 50 mL autoclave and heated at 120 °C for 72 h. The filtered solid product was washed three times successively with N,N-dimethylformamide, tetrahydrofuran, and ethanol to obtain TpAQ-COF.
[0010] (3) MOF525 / TpAQ-COF composite photocatalyst
[0011] MOF 525 (50.0 mg), AQ (0.45 mmol, 107 mg), 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethylureonium hexafluorophosphate (HATU, 100 mg), and N,N-diisopropylethylamine (DIPEA, 60 μL) were dispersed in anhydrous DMF and subjected to sonication for 4 h. The mixture was filtered and washed to obtain a precipitate. The precipitate and Tp (0.3 mmol, 63 mg) were dispersed in a mixture of mesitylene (1.5 mL), 1,4-dioxane (1.5 mL), and aqueous acetic acid (0.6 mL, 6 M), transferred to a reaction vessel, and heated at 120 °C for 72 h. The mixture was then vacuum dried at 100 °C for 24 h, and the final product was collected and named MOF525 / TpAQ-COF with a mass ratio of 1:2, which was named MT-2. Attached Figure Description
[0012] Figure 1 This is a SEM image of MOF525 / TpAQ-COF, which also serves as an appendix to the abstract.
[0013] Figure 2 These are the XRD patterns of MOF525, TpAQ-COF, and MOF525 / TpAQ-COF complexes in different proportions;
[0014] Figure 3 The graph shows the photocatalytic performance of MOF525, TpAQ-COF and MOF525 / TpAQ-COF composites with different ratios in removing RhB.
[0015] Figure 4 These are the kinetic fitting curves for the photocatalytic removal of RhB by MOF525, TpAQ-COF, and MOF525 / TpAQ-COF composites with different ratios. Detailed Implementation
[0016] The 2,6-diaminoanthraquinone, 1,3,5-trihydroxy-2,4,6-trialdehydebenzene selected in this invention have a purity of 97.00%; dioxane, 1,3,5-trimethylbenzene have a purity of 99.8% and 98.00%; 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethylureon hexafluorophosphate, N,N-diisopropylethylamine, ZrOCl2·8H2O have a purity of 99%; H4TCPP has a purity of 97%; benzoic acid, N,N-dimethylformamide, dioxane, tetrahydrofuran, ethanol, and glacial acetic acid are all commercially available analytical grade products; the glassware and equipment used are commonly used laboratory instruments and equipment.
[0017] Example: SEM image of the MOF525 / TpAQ-COF complex as shown below. Figure 1 The diagram shows that the surface of TpAQ-COF is anchored by MOF525, and the MOF525 / TpAQ-COF exhibits a cluster structure. This is related to the covalent growth of TpAQ-COF on the MOF525 surface, confirming the interfacial contact between TpAQ-COF and MOF525. The phase composition and crystal structure of the prepared photocatalyst were characterized by XRD. Figure 2 As shown in the figure, the characteristic peaks in composite samples MT-1, MT-2 and MT-3 correspond to the characteristic peaks of MOF525 and TpAQ-COF, respectively, which proves the successful synthesis of MT composite photocatalysis.
[0018] The photocatalytic performance of the prepared catalyst was evaluated by testing the degradation of RhB in water under simulated sunlight. Figure 3 As shown, it was observed that the sample reached adsorption equilibrium after stirring in the dark for 30 min. After 70 min of illumination, the adsorption of 40 mg·L⁻¹ samples was... -1 The degradation rate of RhB reached 91.7%. Further analysis of the photodegradation curve of RhB was conducted as follows: Figure 4 As shown, ln(C0 / C) was found. t The reaction kinetics show an approximately linear relationship with the illumination time, proving that the reaction kinetics conform to a quasi-first-order kinetic model. The MT-2 complex exhibits the highest RhB photodegradation rate constant (k = 0.03578 min). -1 ).
[0019] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.
Claims
1. A binary MOF525 / TpAQ-COF core-shell structured II heterojunction photocatalyst, characterized in that, The photocatalyst has a porous structure, a large specific surface area, and strong light absorption capacity. Under simulated sunlight conditions, it can absorb 40 mg·L⁻¹ light within 70 minutes. -1 The photocatalytic degradation rate of Rhodamine B (RhB) reached 91.7%.
2. A method for preparing a binary MOF525 / TpAQ-COF organic-organic core-shell structure type II heterojunction photocatalyst, characterized in that, MOF525 / TpAQ-COF was prepared by covalently-bridged in-situ synthesis. The specific synthetic steps are as follows: (1) Preparation of MOF525 2.0 g of benzoic acid and 0.105 g of ZrOCl2·8H2O were added to a 20 mL vial, followed by 8 mL of N,N-dimethylformamide (DMF). The mixture was dissolved uniformly by sonication and heated at 353 K for 2 h. After naturally cooling to room temperature, 0.053 g of 4-carboxyphenylporphyrin (H4TCPP) was added to the above solution and reacted at 80 °C for 24 h. The precipitate was cooled to room temperature, washed three times with DMF and acetone, filtered, and vacuum dried at 60 °C for 12 h to obtain the purple powder MOF 525. (2) Preparation of TpAQ-COF 1,3,5-trihydroxy-2,4,6-trialdehydebenzene (0.3 mmol, 63 mg) and 2,6-diaminoanthraquinone (0.45 mmol, 107 mg) were added separately to dioxane (1.5 mL), trimethylbenzene (1.5 mL), and aqueous acetic acid solution (0.5 mL, 6 M). The mixture was transferred to a stainless steel autoclave and heated at 120 °C for 72 h. The filtered solid product was washed three times with N,N-dimethylformamide, tetrahydrofuran, and ethanol. The final product TpAQ-COF was dried in a vacuum oven at 100 °C for 24 h to obtain a red powder. (3) Preparation of MOF525 / TpAQ-COF composite photocatalyst MOF 525 (50.0 mg), TpAQ-COF (0.45 mmol, 107 mg), 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethylureonium hexafluorophosphate (HATU, 100 mg), and N,N-diisopropylethylamine (DIPEA, 60 μL) were dispersed in anhydrous DMF and sonicated for 4 h. The mixture was filtered and washed to obtain a precipitate. The precipitate and Tp (0.3 mmol) were then reacted. 63 mg) was dispersed in a mixture of mesitylene (1.5 mL), 1,4-dioxane (1.5 mL) and acetic acid aqueous solution, transferred to a 20 mL stainless steel high-pressure reactor, and heated at 120 °C for 72 h. The filtered solid product was washed three times with N,N-dimethylformamide, tetrahydrofuran and ethanol. The final product MOF525 / TpAQ-COF was dried in a vacuum oven at 100 °C for 24 h to obtain a red powder. The mass ratio of MOF 525 to TpAQ-COF in the composite material was 1:
2. A novel type II heterojunction photocatalyst with a core-shell structure was prepared by in-situ synthesis via covalent bridging. The best-performing heterojunction composite was obtained by adjusting the amount of TpAQ-COF. Under simulated light conditions, the optimized MT-2 composite exhibited better performance at 40 mg / L irradiation within 70 min. -1 The degradation rate of RhB was 91.7%. MT-2 exhibited excellent recycling performance, maintaining a high removal rate even after five cycles of photocatalytic reaction. Capture characterization confirmed the transfer mechanism of the type II heterojunction between TpAQ-COF and MOF525. The successful construction of the type II heterojunction can effectively inhibit photogenerated electron-hole recombination, generate more free radicals with strong redox capabilities, and effectively remove RhB from the solution. This study provides a new approach for the efficient degradation of dyes.