Cu-bdc-nh2 material, preparation method and application thereof

Abstract

The application discloses a Cu-BDC-NH2 material and a preparation method and application thereof, the material takes copper ions as an active center and 2-amino terephthalic acid as a ligand, and a gradient heating solvothermal method is adopted to obtain a peroxidase-like material with a mesoscale layered porous structure. The mesoscale layered porous structure can effectively prevent nanoparticle agglomeration, minimize the interface contact resistance, and has excellent peroxidase-like activity. The material can be applied to an electrochemical biosensor, and a sensing interface of the electrochemical biosensor is formed by three-dimensional assembly of the Cu-BDC-NH2 material and a linker. When the material is used for an electrochemical hydrogen peroxide sensor, the detection limit of hydrogen peroxide can reach 57 nM, and the material has high sensitivity, good stability and low cost.

Description

Technical Field

[0001] This invention relates to a sensor material and its application, and particularly to a Cu-BDC-NH2 material, its preparation method, and its application. Background Technology

[0002] Small-molecule hydrogen peroxide (H2O2) is a typical target analyte in many fields, including pharmaceuticals, clinical applications, environmental studies, food processing, and chemical engineering. As a major reactive oxygen species (ROS), H2O2 is a common product of oxidative metabolism in living organisms and plays a crucial role in various biological processes such as cell signal transduction, host defense, protein folding, and oxidative biosynthesis. There is a significant need for effective and accurate detection methods for H2O2. To date, various detection methods have been developed, such as fluorescence methods, colorimetric methods, chromatography, and electrochemical methods. Electrochemical methods are considered more efficient due to their high sensitivity, good selectivity, low cost, and ease of operation. Electrochemical biosensors are typically constructed using biological or non-biological enzymes, detecting the concentration of hydrogen peroxide by detecting changes in the electrical signal generated by the perturbation of the electrochemical system by hydrogen peroxide. Biological enzymes suffer from poor stability, difficulty in storage, and high cost, while non-biological enzymes such as metallic materials, metal-organic frameworks, metal oxides, and carbon materials exhibit excellent electrochemical performance and stability, attracting researchers' attention. However, while common noble metal electrodes such as gold and platinum offer good performance, they are also expensive. Summary of the Invention

[0003] Objectives of the Invention: The first objective of this invention is to provide a Cu-BDC-NH2 material with excellent catalase-like activity, which does not use precious metals and exhibits high sensitivity and good stability. The second objective of this invention is to provide a method for preparing the Cu-BDC-NH2 material. The third objective of this invention is to provide the application of the Cu-BDC-NH2 material in an electrochemical hydrogen peroxide sensor.

[0004] Technical solution: The Cu-BDC-NH2 material of the present invention has a mesoscale layered porous structure and catalase activity, with copper ions as the active center and 2-aminoterephthalic acid as the ligand.

[0005] The Cu-BDC-NH2 material has a particle size of 1 to 5 micrometers.

[0006] The reactants and their proportions play an extremely important role in the structure, morphology and size of the material. In the preferred embodiment of the present invention, the copper ions react with 2-aminoterephthalic acid in a molar ratio of 1:0.5 to 3.

[0007] The preparation method of Cu-BDC-NH2 material according to the present invention is characterized by comprising the following steps:

[0008] (1) Add copper salt and 2-aminoterephthalic acid to N,N-dimethylformamide;

[0009] (2) Heat the temperature to 80-120℃ and grow for 4-6 hours;

[0010] (3) Continue to raise the temperature to 180-220℃ and grow for 4-6 hours to obtain the Cu-BDC-NH2 material.

[0011] In step (2), at this temperature, the metal precursor and ligand undergo a coordination reaction to produce seed crystals.

[0012] In step (3), the seed crystal is used as a nucleus to further grow into particles with a mesoscale layered porous structure. If this time range is exceeded, the material with this structure and scale cannot be generated and becomes a solution or a discolored precipitate.

[0013] Preferably, the concentration of the 2-aminoterephthalic acid is 0.1–0.3 g / mL.

[0014] Preferably, in step (1), the copper salt is copper nitrate, copper chloride, or copper acetate.

[0015] This material can only be obtained within the above-mentioned protection scope. If it is outside the scope, the mesoscale layered porous Cu-BDC-NH2 material described in this invention cannot be obtained.

[0016] The application of the Cu-BDC-NH2 material described in this invention in an electrochemical hydrogen peroxide sensor.

[0017] The sensing interface of the electrochemical hydrogen peroxide sensor is formed by three-dimensional assembly of Cu-BDC-NH2 material and connecting molecules. The exposed amino and carboxyl groups on the surface of the Cu-BDC-NH2 material react with the connecting molecules to form amide bonds. The connecting molecules are 1-ethyl-(3-dimethylaminopropyl)carbodiimide and / or N-hydroxythiosuccinimide.

[0018] Preferably, the sensing interface comprises 90-99 parts by weight of Cu-BDC-NH2 material and 1-10 parts by weight of connecting molecules.

[0019] Mechanism of invention: Highly active layered porous materials typically contain active metal atoms and organic elements such as N, C, and S. Cu atoms, as a transition metal element, have abundant d orbitals and exhibit higher activity. Structure, morphology, and scale play extremely important roles in enzyme activity. Designing the structure of layered porous particles and selecting appropriate structural units to prepare mesoscale layered porous particles is of great significance.

[0020] For mesoscale structural materials, even minor changes in the reactivity and ratio of reactants, as well as preparation conditions, during nucleation and growth can alter the material's morphology and size. This invention uses copper ions and 2-aminoterephthalic acid as structural units and employs a gradient heating solvothermal method to control the particle growth process and morphology, thus preparing a mesoscale layered porous material. The lone pair electrons of the carboxyl and amino groups in the 2-aminoterephthalic acid molecule have strong coordination interactions with copper ions. Under gradient heating conditions, these coordination links form a three-dimensional layered porous structure between the metal ions and ligands.

[0021] The microstructure of functional materials has a significant impact on electrochemical catalytic activity. Layered porous microstructure materials can effectively prevent nanoparticle aggregation and minimize interfacial contact resistance due to their unique characteristics. Compared with similar products, they have the following advantages: (1) more active sites and shorter ion diffusion radius; (2) porous structure facilitates electrolyte entry and buffers volume changes during the reaction process; (3) enhanced light scattering ability, which can form high-performance materials.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) Cu-BDC-NH2 material has a mesoscale layered porous structure, which can effectively prevent the aggregation of nanoparticles, minimize the interfacial contact resistance, and has excellent catalase-like activity; (2) The preparation method does not use expensive metals, and the preparation process is simple and reproducible; (3) When Cu-BDC-NH2 material is applied to an electrochemical hydrogen peroxide sensor, the detection limit of hydrogen peroxide can reach 57 nM, and it has high sensitivity, good stability and low cost. Attached Figure Description

[0023] Figure 1 A schematic diagram illustrating the basic principle of preparing Cu-BDC-NH2 structure;

[0024] Figure 2 SEM image of the Cu-BDC-NH2 material prepared in Example 1;

[0025] Figure 3 This is a high-magnification SEM image of the Cu-BDC-NH2 material prepared in Example 1;

[0026] Figure 4 The image shows the catalase-like activity test result of the Cu-BDC-NH2 material prepared in Example 1.

[0027] Figure 5 The test curve (IT curve) shows the performance of the GCE / Cu-BDC-NH2 electrode in detecting hydrogen peroxide in Example 5.

[0028] Figure 6This is a linear relationship graph between hydrogen peroxide at different concentrations and electric current in Example 5;

[0029] Figure 7 The test curve (IT curve) for the detection of hydrogen peroxide by the GCE / Cu-BDC-NH2 electrode in Example 6 is shown.

[0030] Figure 8 The graph shows the linear relationship between hydrogen peroxide at different concentrations and electric current in Example 6.

[0031] Figure 9 SEM image of the material prepared in Comparative Example 1;

[0032] Figure 10 SEM image of the material prepared for Comparative Example 2. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the embodiments.

[0034] Example 1

[0035] The Cu-BDC-NH2 material of the present invention uses copper ions as the active center and 2-aminoterephthalic acid as the ligand, wherein the molar ratio of copper ions to 2-aminoterephthalic acid is 1:0.5.

[0036] Its preparation method includes the following steps:

[0037] (1) Weigh 10 mmol of copper nitrate and 5 mmol of 2-aminoterephthalic acid and dissolve them in 20 mL of N,N-dimethylformamide. Stir with a magnetic stirrer for 30 minutes.

[0038] (2) Transfer the mixed solution of copper nitrate and 2-aminoterephthalic acid in (1) to a polytetrafluoroethylene high-pressure reactor and heat it to 100°C for 5 hours; then heat it to 200°C for 5 hours; then cool it naturally to room temperature (change the reaction temperature and time to the optimal reaction temperature and time);

[0039] (3) Centrifuge the reaction product at 5000 rpm to obtain the precipitate, and wash it twice with N,N-dimethylformamide;

[0040] (4) The washed precipitate was vacuum dried at 160°C to activate the sample, resulting in a dark blue powder.

[0041] The prepared Cu-BDC-NH2 dark blue powder was observed using a scanning electron microscope, and the resulting SEM image is shown below. Figure 2 As shown, higher magnification SEM images are as follows: Figure 3 As shown, layered porous Cu-BDC-NH2 particles with a particle size of approximately 1–5 micrometers can be observed.

[0042] Example 2

[0043] The Cu-BDC-NH2 material of the present invention uses copper ions as the active center and 2-aminoterephthalic acid as the ligand, wherein the molar ratio of copper ions to 2-aminoterephthalic acid is 1:1. Its preparation method is the same as in Example 1.

[0044] Example 3

[0045] The Cu-BDC-NH2 material of the present invention uses copper ions as the active center and 2-aminoterephthalic acid as the ligand, wherein the molar ratio of copper ions to 2-aminoterephthalic acid is 1:3. Its preparation method is the same as in Example 1.

[0046] Example 4

[0047] Catalase activity test of Cu-BDC-NH2 material: The nanoenzyme activity of Cu-BDC-NH2 particles prepared in Example 1 was tested in a mixed solution of 3,3,5,5-tetramethylbenzidine and hydrogen peroxide. The test results are as follows: Figure 4 As shown.

[0048] Depend on Figure 4 The control group was a colorless solution, while the experimental group was a blue solution. This indicates that the layered porous Cu-BDC-NH2 particles catalyze the decomposition of hydrogen peroxide to produce reactive oxygen species, which in turn oxidize 3,3,5,5-tetramethylbenzidine, turning it blue. This confirms that the layered porous Cu-BDC-NH2 particles possess nanozyme-like, catalase-like activity.

[0049] Example 5

[0050] The application of Cu-BDC-NH2 materials in electrochemical biosensors includes the following steps:

[0051] Step 1: Pretreatment of glassy carbon electrode

[0052] Before modification, the glassy carbon electrode was polished to a mirror surface with 0.3 μm alumina powder, then washed with deionized water and dried with nitrogen to obtain a glassy carbon electrode for use.

[0053] Step 2: Preparation of the mixed coating solution

[0054] 0.5 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.5 parts by weight of N-hydroxythiosuccinimide were dissolved in water, and then 99 parts by weight of Cu-BDC-NH2 mesoscale layered porous particles prepared in Example 1 were added and ultrasonically dispersed to obtain a mixed solution.

[0055] Step 3: Modify the electrode

[0056] 10 μL of the mixed coating solution was transferred using a 10 μL pipette and dropped onto the surface of the prepared glassy carbon electrode. The electrode was then allowed to dry naturally at room temperature for 6 hours to obtain the modified glassy carbon electrode, denoted as GCE / Cu-BDC-NH2.

[0057] like Figure 5 In PBS solution, glassy carbon electrode (GCE) and GCE / Cu-BDC-NH2 were used as working electrodes to perform IT curve tests. Adding 100 nM hydrogen peroxide solution at regular intervals revealed that GCE showed almost no current response to hydrogen peroxide during the test, while the layered porous Cu-BDC-NH2 particle-modified GCE exhibited a significant current response to hydrogen peroxide.

[0058] like Figure 6 Based on the linear relationship between hydrogen peroxide concentration and current, the detection limit of hydrogen peroxide is approximately 57 nM, indicating that the electrochemical biosensor constructed based on layered porous Cu-BDC-NH2 particles has good sensitivity for detecting hydrogen peroxide.

[0059] Example 6

[0060] The application of Cu-BDC-NH2 materials in electrochemical biosensors includes the following steps:

[0061] Steps 1 and 3 are the same as in Example 5.

[0062] Step 2: Preparation of the mixed coating solution

[0063] Five parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and five parts by weight of N-hydroxythiosuccinimide were dissolved in water, and then 90 parts by weight of Cu-BDC-NH2 mesoscale layered porous particles prepared in Example 1 were added and ultrasonically dispersed to obtain a mixed solution.

[0064] like Figure 7 In PBS solution, glassy carbon electrode (GCE) and GCE / Cu-BDC-NH2 were used as working electrodes to perform IT curve tests. Adding 100 nM hydrogen peroxide solution at regular intervals revealed that GCE showed almost no current response to hydrogen peroxide during the test, while the layered porous Cu-BDC-NH2 particle-modified GCE exhibited a significant current response to hydrogen peroxide.

[0065] like Figure 8 Based on the linear relationship between different concentrations of hydrogen peroxide and current, the detection limit of hydrogen peroxide is approximately 65 nM, indicating that the electrochemical biosensor constructed based on layered porous Cu-BDC-NH2 particles has good sensitivity in detecting hydrogen peroxide.

[0066] Comparative Example 1

[0067] Based on Example 1, the heating conditions were changed to "heat to 100°C and react for 3 hours; then heat to 200°C and react for 3 hours" to prepare the material. SEM images are shown below. Figure 9 As shown.

[0068] Depend on Figure 9 As can be seen, the material did not form layered porous particles, but rather fragmented.

[0069] Comparative Example 2

[0070] Based on Example 1, the linker 2-aminoterephthalic acid was replaced with terephthalic acid, while other conditions remained unchanged, and the material was prepared. SEM images are shown below. Figure 10 As shown.

[0071] Depend on Figure 10 Therefore, the material is in sheet form, rather than in layered porous granular form.

Claims

1. A Cu-BDC-NH2 material, characterized in that, With copper ions as the active center and 2-aminoterephthalic acid as the ligand, it has a mesoscale layered porous particle structure and catalase activity; the molar ratio of copper ions to 2-aminoterephthalic acid is 1:0.5~3; the material is prepared by a solvothermal method with gradient heating, including the following steps: (1) adding copper salt and 2-aminoterephthalic acid to N,N-dimethylformamide; (2) Raise the temperature to 80~120℃ and grow for 4~6 hours; (3) Continue to raise the temperature to 180~220℃ and grow for 4~6 hours to obtain the Cu-BDC-NH2 material.

2. The Cu-BDC-NH2 material according to claim 1, characterized in that, The Cu-BDC-NH2 material has a particle size of 1~5 micrometers.

3. A method for preparing the Cu-BDC-NH2 material according to claim 1 or 2, characterized in that, The solvothermal method employing gradient heating includes the following steps: (1) Add copper salt and 2-aminoterephthalic acid to N,N-dimethylformamide; (2) Raise the temperature to 80~120℃ and grow for 4~6 hours; (3) Continue to raise the temperature to 180~220℃ and grow for 4~6 hours to obtain the Cu-BDC-NH2 material.

4. The method for preparing Cu-BDC-NH2 material according to claim 3, characterized in that, The concentration of the 2-aminoterephthalic acid is 0.1~0.3 g / mL.

5. The method for preparing Cu-BDC-NH2 material according to claim 3, characterized in that, In step (1), the copper salt is copper nitrate, copper chloride, or copper acetate.

6. The application of the Cu-BDC-NH2 material according to claim 1 or 2 in an electrochemical hydrogen peroxide sensor.

7. The application according to claim 6, characterized in that, The sensing interface of the electrochemical hydrogen peroxide sensor is formed by three-dimensional assembly of Cu-BDC-NH2 material and connecting molecules.

8. The application according to claim 7, characterized in that, The linker molecules are 1-ethyl-(3-dimethylaminopropyl)carbodiimide and / or N-hydroxythiosuccinimide.

9. The application according to claim 7 or 8, characterized in that, The sensing interface comprises, by weight, 90-99 parts of Cu-BDC-NH2 material and 1-10 parts of connecting molecules.

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