Copper-based MOF nanofiber membranes, methods of making and applications thereof

Abstract

This invention pertains to the field of glucose detection and discloses a copper-based MOF nanofiber membrane, its preparation method, and its application. The copper-based MOF nanofiber membrane is prepared by a method comprising the following steps: (1) adding a polyvinyl alcohol solution to a copper acetate solution to form a spinning solution; (2) electrospinning the spinning solution to obtain a copper-based nanofiber membrane; (3) calcining the copper-based nanofiber membrane in an air atmosphere to obtain a copper oxide fiber membrane; (4) mixing the copper oxide fiber membrane with an organic ligand, adding a solvent, and performing a hydrothermal reaction to obtain a copper-based MOF nanofiber membrane. The copper-based MOF nanofiber membrane prepared by this invention, as an electrode material for an enzyme-free glucose sensor, can improve conductivity, sensitivity, and anti-interference performance. Furthermore, the preparation method is simple and can be mass-produced.

Description

Technical Field

[0001] This invention relates to the field of glucose detection, mainly to the field of enzyme-free glucose sensor electrode materials, and specifically to a copper-based MOF nanofiber membrane, its preparation method, and its application. Background Technology

[0002] With the advancement of modernization, the improvement of living standards, changes in dietary habits, and the deepening of population aging, the number of diabetic patients has increased dramatically. For hundreds of millions of diabetic patients, obtaining accurate blood glucose concentrations every day is an essential procedure for maintaining their health. The hundreds of millions of blood glucose monitoring sessions per day provide a huge market demand and application prospect for glucose sensors.

[0003] Several methods have been developed for the quantitative detection of glucose. For example, methods based on glucose oxidase (GO)... x A glucose biosensor, but due to GO x The activity of glucose is highly sensitive to environmental factors such as temperature, humidity, pH, and toxic substances, leading to stability and reproducibility issues during preparation, transportation, storage, and use, which limits its practical applications. Electrochemical methods are widely used due to their simplicity, rapid response, and low cost; however, electrochemical glucose sensors are not yet perfect in terms of technology and materials, such as their anti-interference capabilities and sensitivity, which need further improvement.

[0004] Metal-organic frameworks (MOFs) possess advantages such as simple synthesis methods, controllable structure, stable and flexible pore characteristics, and large specific surface area, making them a hot research topic. Cu-BTC is one of the classic MOF materials. Its preparation method is simple, and it can be synthesized in one step using a hydrothermal method, with low raw material costs, making it economical. Various analytical results also show that Cu-BTC has good adhesion during film formation, is easy to modify, and has good water stability. In recent years, the performance and applications of Cu-BTC have attracted much attention, especially in the field of catalysis, where it can catalyze multiple organic reactions.

[0005] Patent CN115047041A discloses a method for preparing an enzyme-free electrochemical glucose sensor based on a conductive metal-organic framework (Cu3(HHTP)2). The method employs a hydrothermal synthesis of Cu3(HHTP)2 electrode material, a simple process that overcomes the shortcomings of current MOF-based enzyme-free electrochemical sensing materials, such as poor conductivity or surface area reduction and structural damage caused by doping and pyrolysis of the original MOF material. While the material exhibits high detection sensitivity in this work, the detection limit needs improvement. Patent CN114354692A discloses a method for preparing and applying an enzyme-free glucose sensor electrode material. It involves preparing cobalt-based nanofibers through electrospinning and then achieving phosphorus doping through calcination and phosphating. This method has advantages such as low cost, a large specific surface area of ​​the obtained product, simple operation, and fast detection speed; however, its anti-interference performance needs improvement. Patent CN107192753A discloses a glucose sensing electrode, its preparation method, and its application. The electrode includes a conductive glass layer, a Cu2O layer composited on the surface of the conductive glass layer, and a Cu-BTC metal-organic framework material composited on the surface of the Cu2O layer. This electrode has high photoelectric conversion efficiency. Applying it to glucose detection can effectively improve the sensitivity of glucose detection, broaden the linear range of glucose detection, and achieve a low detection limit. However, its anti-interference performance needs to be improved.

[0006] In summary, there is a need to find a simple and efficient method to prepare enzyme-free glucose sensor electrode materials, which also possess a large specific surface area, numerous active sites, and good anti-interference properties, in order to meet their application as copper-based nanomaterials in glucose detection. Summary of the Invention

[0007] This invention provides a copper-based MOF nanofiber membrane, its preparation method, and its application. The technical problem to be solved is that the preparation method has the advantages of low raw material cost, simple operation, and fast response, while also giving the material high sensitivity, low detection limit, and good anti-interference performance.

[0008] The present invention solves the technical problem by adopting the following technical solution:

[0009] A copper-based MOF nanofiber membrane, characterized in that it is prepared by a method comprising the following steps:

[0010] (1) Add polyvinyl alcohol solution to copper acetate solution to form spinning solution;

[0011] (2) Electrospinning the spinning solution to obtain a copper-based nanofiber membrane;

[0012] (3) The copper-based nanofiber membrane is calcined in air to obtain a copper oxide fiber membrane;

[0013] (4) The copper oxide fiber membrane is mixed with an organic ligand, a solvent is added, and a hydrothermal reaction is carried out to obtain a copper-based MOF nanofiber membrane.

[0014] Preferably, in the copper-based MOF nanofiber membrane, the mass fraction of copper acetate in the copper acetate solution is 15-25%, preferably 16%-23.5%, more preferably 22.5%-23.5%; the mass fraction of polyvinyl alcohol in the polyvinyl alcohol solution is 10-12%, preferably 10%, and the volume ratio of copper acetate aqueous solution to polyvinyl alcohol solution is 1:(1.5:2.5).

[0015] Preferably, in the copper-based MOF nanofiber membrane described above, in step (1), the mass ratio of copper acetate to polyvinyl alcohol in the spinning solution is (1.0-1.2):1, more preferably (1.1-1.2):1.

[0016] Preferably, in the above-mentioned copper-based MOF nanofiber membrane, the electrospinning process in step (2) includes the following steps:

[0017] The spinning solution was transferred to a 10 mL syringe for spinning. The flow rate was set to 0.4–0.45 mL / h, the high voltage to 16–17.5 kV, the distance from the copper mesh to the needle to 13–15 cm, and the rotation speed of the receiving plate to 30–35 r / min. A copper gel fiber membrane was obtained on the copper mesh.

[0018] Preferably, in the copper-based MOF nanofiber membrane described above, in step (3), the calcination temperature is 300-420℃, preferably 400-420℃, the calcination time is 100-150min, and the heating rate is 1-2℃ / min.

[0019] Preferably, in the copper-based MOF nanofiber membrane described above, in step (4), the molar ratio of the organic ligand to the copper oxide fiber membrane is (0.4-2.2):1, more preferably (0.8-2.2):1, and even more preferably (2.0-2.2):1.

[0020] Preferably, in the above-mentioned copper-based MOF nanofiber membrane, the organic ligand is selected from pyromellitic acid, terephthalic acid, or pyromellitic tetracarboxylic acid, with pyromellitic acid being the most preferred.

[0021] Preferably, in the above-mentioned copper-based MOF nanofiber membrane, the solvent is selected from methanol, ethanol, or N,N-dimethylformamide.

[0022] Preferably, in the copper-based MOF nanofiber membrane described above, in step (4), the temperature of the hydrothermal reaction is 110℃~140℃, and the reaction time is 8~48h, preferably 8~15h, and more preferably 8~12h.

[0023] This invention also provides a method for preparing the above-mentioned copper-based MOF nanofiber membrane, characterized by comprising the following steps:

[0024] (1) Add polyvinyl alcohol solution to copper acetate solution to form spinning solution;

[0025] (2) Electrospinning the spinning solution to obtain a copper-based nanofiber membrane;

[0026] (3) The copper-based nanofiber membrane is calcined in air to obtain a copper oxide fiber membrane;

[0027] (4) The copper oxide fiber membrane is mixed with an organic ligand, a solvent is added, and a hydrothermal reaction is carried out to obtain a copper-based MOF nanofiber membrane.

[0028] The present invention also provides an enzyme-free glucose sensor electrode material, characterized in that it comprises the above-mentioned copper-based MOF nanofiber membrane.

[0029] The present invention also provides an enzyme-free glucose sensor electrode, characterized in that it comprises the above-mentioned electrode material.

[0030] The present invention also provides the above-mentioned copper-based MOF nanofiber membrane, the above-mentioned enzyme-free glucose sensor electrode material, or the application of the above-mentioned enzyme-free glucose sensor electrode in the field of glucose detection.

[0031] The advantages of this invention are: (1) This invention can prepare a self-supporting flexible pure MOF fiber membrane with a large specific surface area and high porosity, and many active sites, which can significantly improve its electrochemical activity and conductivity, and the resulting material has high sensitivity. (2) The material, when used as an electrode for electrochemical sensing, exhibits a good sensitizing effect and has good anti-interference properties against non-glucose components in human blood glucose. (3) The self-supporting flexible pure MOF fiber membrane effectively avoids catalyst aggregation and particle shedding, has porosity, can be prepared in large quantities, and has a controllable morphology. Attached Figure Description

[0032] Figure 1 The image shows the XRD pattern of the CuO fiber membrane obtained in Example 1.

[0033] Figure 2 This is a scanning electron microscope image of the CuO fiber membrane obtained in Example 1.

[0034] Figure 3 The image shows the XRD pattern of the Cu-BTC fiber membrane obtained in Example 1.

[0035] Figure 4 This is a scanning electron microscope image of the Cu-BTC fiber membrane obtained in Example 1.

[0036] Figure 5The cyclic voltammetry curves are for the Cu-BTC fiber membrane obtained in Example 1.

[0037] Figure 6 The current-time curve of the Cu-BTC fiber membrane obtained in Example 1 is shown.

[0038] Figure 7 The graph shows the anti-interference curve of the Cu-BTC fiber membrane obtained in Example 1.

[0039] Figure 8 The graph shows the anti-interference curve of the Cu-BTC fiber membrane obtained in Example 2.

[0040] Figure 9 The graph shows the anti-interference curve of the Cu-BTC fiber membrane obtained in Example 3. Detailed Implementation

[0041] Given that the anti-interference ability and sensitivity of current electrochemical glucose sensors still need to be improved, this invention provides a copper-based MOF nanofiber membrane. In general, this invention adopts the following two technologies: (1) Copper-based nanofiber membranes are prepared by electrospinning, and then copper-based MOFs are obtained as enzyme-free glucose sensor materials through further hydrothermal synthesis. Electrospinning technology is simple to operate and can continuously produce uniform nanofibers with high aspect ratio. The composition of the synthesized materials is controllable, with a large specific surface area and good conductivity. Unlike traditional preparation methods, the nanofibers prepared by electrospinning are usually interlaced to form a nanofiber membrane of a certain thickness, which can be directly used as a conductive matrix for the assembly and growth of various nanomaterials. That is to say, the nanofiber membranes obtained have the characteristics of large specific surface area and high porosity, and the electrode materials obtained have high sensitivity and fast response. (2) Copper-based MOFs in MOF materials are selected as the research object of enzyme-free glucose sensor electrode materials, and copper acetate is selected as the copper salt material. Studies have shown that copper-based MOF materials have greater advantages than other MOFs in liquid phase separation, and have a large specific surface area, are easy to modify, and have good water stability. They also have good adhesion during membrane formation. The enzyme-free electrochemical glucose sensor constructed using them has the characteristics of high sensitivity, wide detection linear range, and low detection limit.

[0042] In a preferred embodiment, the present invention provides a simple and efficient method for preparing enzyme-free glucose sensor electrode materials, comprising the following steps:

[0043] (1) Add a 10% PVA solution to the dissolved copper acetate solution and mix well to form a spinning solution;

[0044] (2) Electrospinning the spinning solution to obtain a copper-based fiber film;

[0045] (3) After calcining the product obtained in step (2), a copper oxide fiber membrane is obtained;

[0046] (4) The product obtained in step (3) is added to a mixed solution of ethanol and water of pyromellitic acid for hydrothermal reaction to obtain the Cu-BTC enzyme-free glucose sensor electrode material.

[0047] In this invention, an electrospinning method is used to prepare the substrate. Electrospinning is a simple and controllable method for preparing nanoparticle composite porous nanofibers. The nanofibers prepared by electrospinning are usually arranged in an interlaced manner to form a nanofiber film of a certain thickness, which can be directly used as a conductive substrate for the assembly and growth of various nanomaterials.

[0048] In this invention, copper-based MOFs (Cu-MOFs) themselves contain variable-valence metal ions Cu. 2+ Under an applied voltage, the electron transfer process in the Cu(II)-MOF / Cu(I)-MOF redox couple promotes the gain and loss of electrons in the analyte, thus exhibiting high electrochemical activity. Electrochemically active MOFs, due to their nano-open pore structure, allow glucose molecules to fully contact their surface and freely enter and exit. If the electron and ion transport properties of the framework are sufficiently good, the metal ion utilization rate can reach 100%, showing potential application value in the enzyme-free detection and analysis of glucose. Different copper-based MOFs have different framework structures and pore sizes, and Cu-BTC exhibits certain good anti-interference properties.

[0049] In this invention, the copper-based MOF fiber membrane was prepared using a "dissolution-reprecipitation" mechanism. The oxide dissolves at the solid-liquid interface into the solution, immediately forming a stable MOF phase at the same location as the dissolved precursor. Previous studies have shown that MOF fiber membranes prepared via the "dissolution-reprecipitation" mechanism effectively avoid catalyst aggregation and particle shedding.

[0050] In this invention, copper-based MOF refers to a metal-organic framework material with copper ions as the metal ion. Cu-BTC refers to a MOF material synthesized with copper ions as the metal ion and pyromellitic acid as the organic ligand, also known as HUKST-1. Cu-BDC refers to a MOF material synthesized with copper ions as the metal ion and terephthalic acid as the organic ligand. Cu-BTEC refers to a MOF material synthesized with copper ions as the metal ion and pyromellitic acid as the organic ligand.

[0051] The copper-based MOF nanofiber membrane, its preparation method, and its application are further illustrated below through specific embodiments.

[0052] In the following examples, the PVA model is 1788, purchased from Aladdin, and all other reagents used were purchased from Sinopharm Reagents.

[0053] The information of the instruments used in the embodiments is shown in the table below:

[0054] Table 1 Instrument Information Sheet

[0055] Reagents / Instruments Specifications / Model Manufacturer / Source spinning machine E05-001 Foshan Light Zinc Tubular furnace OTF-1200X Hefei Kejing Scanning electron microscope Zeiss Supra 40 Carl Zeiss, Germany X-ray diffraction instrument PANalytical X-Pert PRO MPD Panaco, Netherlands Electrochemical workstation CHI600E Shanghai Chenhua

[0056] Example 1

[0057] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0058] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0059] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0060] (3) The fiber membrane was placed in a muffle furnace and calcined at 400°C in air for 2 hours with a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0061] (4) Weigh 0.1 g of CuO fiber membrane and 0.5376 g of H3BTC (1,3,5-trimethylbenzenetricacid, also known as pyromellitic acid), add them to a mixed solution of 15 mL of ethanol and water with a volume ratio of V / V = 1:1, stir for 10 min, transfer the mixture to a 50 mL LFlon reactor, heat to 110 °C, and react for 8 h. After centrifugation, wash three times with ethanol and water, and dry under vacuum at 80 °C for 12 h to obtain a copper-based MOF fiber membrane, which is used as an electrode material.

[0062] The XRD pattern of the copper oxide fiber membrane obtained in step (3) is as follows: Figure 1 As shown, comparison with the standard CuO card reveals that the obtained copper oxide fiber membrane is pure copper oxide; the scanning electron microscope image is shown below. Figure 2 As shown in the figure, the fiber diameter is 0.1–0.5 μm.

[0063] The scanning electron microscope image of the Cu-BTC fiber membrane obtained in step (4) is shown below. Figure 3 As shown, a comparison with the HUKST-1 standard card confirms that this embodiment successfully synthesized the HUKST-1 copper-based MOF material; the scanning electron microscope image is shown below. Figure 4As shown in the figure, the diameter of the copper-based MOF fiber material obtained in this embodiment is 200-400 nm.

[0064] The electrode material obtained in step (4) was subjected to cyclic voltammetry in a mixed solution of 0.1 M sodium hydroxide and 0.1 M sodium hydroxide + 1 mM glucose. The detection process was as follows: 2 mg of the sample obtained in step (4) was dispersed in 50 μL of Nafion solution, 150 μL of anhydrous ethanol and 800 μL of deionized water and ultrasonically dispersed evenly. 5 μL of the dispersion was then dropped onto the treated glassy carbon electrode and allowed to air dry naturally. This glassy carbon electrode was used as the working electrode, the saturated calomel electrode as the reference electrode, and the platinum wire as the counter electrode, forming a three-electrode system. The three-electrode system was placed in 20 mL of 0.1 M sodium hydroxide solution and 20 mL of a mixed solution of 0.1 M sodium hydroxide + 1 mM glucose for cyclic voltammetry (CV) scanning. The scanning range was -0.1 to 0.7 V, and the scanning rate was 50 mV / s. The results are as follows: Figure 5 As shown in the figure, the current value of the sample containing glucose is greater in the 0.5-0.65V range, indicating that the material has the ability to oxidize glucose.

[0065] The material obtained in step (4) was added dropwise to a 2M glucose solution, and the current-time curve was plotted as follows: Figure 6 As shown, the detection process was as follows: the three-electrode system was placed in 20 mL of 0.1 M sodium hydroxide solution, and starting from 100 seconds, 20 μL of 2 M glucose solution was added dropwise every 20 seconds. The current-time curve was obtained, and by fitting the curve, the sensitivity of the material was found to be 1146 μA·mM. -1 ·cm -2 .

[0066] Figure 7 The interference immunity curve for this example is shown. The detection process was as follows: the three-electrode system was placed in 20 mL of 0.1 M sodium hydroxide solution. Starting from 150 seconds, 20 μL each of 10 mM glucose (Glu), 1 mM sodium chloride (NaCl), 1 mM potassium chloride (KCl), 1 mM uric acid (UA), 1 mM sucrose (Suc), 1 mM maltose (Mal), 1 mM dopamine (DA), 1 mM ascorbic acid (AA), and 10 mM glucose (Glu) were added dropwise every 30 seconds. As can be seen from the graph, the current barely increased after the addition of sodium chloride, potassium chloride, uric acid, sucrose, maltose, dopamine, and ascorbic acid, indicating that the material has excellent interference immunity.

[0067] Example 2

[0068] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0069] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0070] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0071] (3) The fiber membrane was placed in a muffle furnace and calcined at 400°C for 2 hours in air atmosphere at a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0072] (4) Weigh 0.1g CuO fiber membrane and 0.5376g H3BTC (1,3,5-benzenetricarboxylic acid), add them to a 15mL mixture of ethanol and water with a volume ratio of V / V = 1:1, stir for 10min, transfer the mixture to a 50mL Teflon reactor, heat to 110℃, keep the temperature constant for 10h, centrifuge the product, wash it three times with ethanol and water, and dry it under vacuum at 80° for 12h to obtain a copper-based MOF fiber membrane, which is used as an electrode material.

[0073] The sensitivity of the electrode material obtained in this example was measured to be 1351.76 μA·mM using the same method as in Example 1. -1 ·cm -2 .

[0074] Figure 8 The interference immunity curve for this example is shown. The detection process was as follows: the three-electrode system was placed in 20 mL of 0.1 M sodium hydroxide solution. Starting from 200 seconds, 20 μL each of 10 mM glucose (Glu), 1 mM potassium chloride (KCl), 1 mM sodium chloride (NaCl), 1 mM sucrose (Suc), 1 mM maltose (Mal), 1 mM uric acid (UA), 1 mM dopamine (DA), 1 mM ascorbic acid (AA), and 10 mM glucose (Glu) were added dropwise every 30 seconds. As can be seen from the graph, the current barely increased after the addition of sodium chloride, potassium chloride, sucrose, maltose, uric acid, dopamine, and ascorbic acid, indicating that the material has excellent interference immunity.

[0075] Example 3

[0076] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0077] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0078] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0079] (3) The fiber membrane was placed in a muffle furnace and calcined at 400°C in air for 1 hour with a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0080] (4) Weigh 0.1 g of CuO fiber membrane and 0.5376 g of H3BTC (1,3,5-benzenetricarboxylic acid), add them to a 15 mL mixture of ethanol and water in a volume ratio of 1:1 (V / V = 1:1), stir for 10 min, transfer the mixture to a 50 mL Teflon reactor, heat to 110 °C, and react for 10 h. After centrifugation, wash three times with hot ethanol and water, and dry under vacuum at 80 °C for 12 h to obtain Cu-BTC fiber membrane, which is used as electrode material.

[0081] The sensitivity of the electrode material obtained in this example was measured to be 805.24 A·mM using the same method as in Example 1. -1 ·cm -2 .

[0082] Figure 9 The interference immunity curve for this example is shown. The detection process was as follows: the three-electrode system was placed in 20 mL of 0.1 M sodium hydroxide solution. Starting from 150 seconds, 20 μL each of 10 mM glucose (Glu), 1 mM potassium chloride (KCl), 1 mM sodium chloride (NaCl), 1 mM uric acid (UA), 1 mM maltose (Mal), 1 mM sucrose (Suc), 1 mM ascorbic acid (AA), 1 mM dopamine (DA), and 10 mM glucose (Glu) were added dropwise every 30 seconds. As can be seen from the graph, the current barely increased after the addition of sodium chloride, potassium chloride, uric acid, maltose, sucrose, ascorbic acid, and dopamine, indicating that the material has excellent interference immunity.

[0083] Example 4

[0084] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0085] (1) Prepare a 12wt% PVA solution, dissolve 0.6g of copper acetate solid in 3ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:1.5.

[0086] (2) Copper gel fiber membranes were obtained by electrospinning under the conditions of a spinning distance of 15 cm, a voltage of 17 kV, a humidity of less than 50%, and a liquid supply rate of 0.45 ml / h. The copper gel fiber membranes obtained by electrospinning were dried at 80 °C for 12 h.

[0087] (3) The fiber membrane was calcined in a muffle furnace at 420℃ under air protection for 2 hours, with a heating rate of 1℃·min. -1 A CuO fiber membrane was obtained.

[0088] (4) Weigh 0.1 g of CuO fiber membrane and 0.5376 g of H3BTC (1,3,5-benzenetricarboxylic acid), add them to 15 mL of a mixed solution of ethanol and water with a volume ratio of V / V = 1:1, stir for 10 min, transfer the mixture to 50 mL of Teflon reactive gold and heat to 110 °C for 10 h. After centrifugation, wash three times with hot ethanol and water, and dry under vacuum at 80 °C for 12 h.

[0089] The sensitivity of the electrode material obtained in this example was measured to be 1203.41 μA·mM using the same method as in Example 1. -1 ·cm -2 .

[0090] Example 5

[0091] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0092] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0093] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0094] (3) The fiber membrane was placed in a muffle furnace and calcined at 300°C in air for 2 hours with a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0095] (4) Weigh 0.1 g of CuO fiber membrane and 0.5376 g of H3BTC (1,3,5-benzenetricarboxylic acid), add them to a 15 mL mixture of ethanol and water in a volume ratio of 1:1 (V / V = 1:1), stir for 10 min, transfer the mixture to a 50 mL Teflon reactor, heat to 110 °C, and react for 10 h. After centrifugation, wash three times with hot ethanol and water, and dry under vacuum at 80 °C for 12 h to obtain Cu-BTC fiber membrane, which is used as electrode material.

[0096] The sensitivity of the electrode material obtained in this example was 397.99 μA·mM, measured using the same method as in Example 1. -1 ·cm -2 .

[0097] Example 6

[0098] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0099] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0100] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0101] (3) The fiber membrane was placed in a muffle furnace and calcined at 350°C in air for 1 hour, with a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0102] (4) Weigh 0.1 g of CuO fiber membrane and 0.5376 g of H3BTC (1,3,5-benzenetricarboxylic acid), add them to a 15 mL mixture of ethanol and water in a volume ratio of 1:1 (V / V = 1:1), stir for 10 min, transfer the mixture to a 50 mL Teflon reactor, heat to 110 °C, and react for 10 h. After centrifugation, wash three times with hot ethanol and water, and dry under vacuum at 80 °C for 12 h to obtain Cu-BTC fiber membrane, which is used as electrode material.

[0103] The sensitivity of the electrode material obtained in this example was 239.63 μA·mM, measured using the same method as in Example 1. -1 ·cm -2 .

[0104] Example 7

[0105] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0106] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0107] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0108] (3) The fiber membrane was placed in a muffle furnace and calcined at 400°C in air for 2 hours, with a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0109] (4) Weigh 0.0595 g of CuO fiber membrane and 0.1207 g of H3BDC (terephthalic acid), add them to 14.5 mL of DMF solution, stir for 10 min, transfer the mixture to a 50 mL Teflon reactor, heat to 110 °C, and react for 36 h. After centrifugation, wash three times with DMF, and dry under vacuum at 80 °C for 12 h to obtain Cu-BDC fiber membrane, which is used as electrode material.

[0110] The sensitivity of the electrode material obtained in this example was 254.79 μA·mM, measured using the same method as in Example 1. -1 ·cm -2 .

[0111] Example 8

[0112] The preparation process of copper-based MOF fiber material for enzyme-free glucose sensor electrode material is as follows:

[0113] (1) Prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0114] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0115] (3) The fiber membrane was placed in a muffle furnace and calcined at 400°C in air for 2 hours, with a heating rate of 1°C·min. -1 CuO fiber membrane was obtained.

[0116] (4) 0.127 g of H3BTEC (pyromellitic tetracarboxylic acid) was dissolved in 8 mL of anhydrous methanol solution. 0.040 g of CuO fiber membrane aqueous solution was added to the above solution, and the mixture was stirred for 10 min. The mixture was then transferred to a 50 mL Teflon reactor and heated to 140 °C for 48 h. After centrifugation, the membrane was washed three times with hot ethanol and water, and dried under vacuum at 80 °C for 12 h to obtain Cu-BTEC fiber membrane, which was used as electrode material.

[0117] The sensitivity of the electrode material obtained in this example was measured to be 622.00 μA·mM using the same method as in Example 1. -1 ·cm -2 .

[0118] Comparative Example 1

[0119] The preparation process of Cu-BTC fiber membrane is as follows:

[0120] (1) Prepare a 10wt% PVA solution (polyvinyl alcohol), dissolve 0.38g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:3.

[0121] (2) The spinning solution was transferred to a 10mL syringe for spinning. The flow rate was set to 0.45ml / h, the high voltage to 17kV, the distance from the copper mesh to the needle to 15cm, the rotation speed of the receiving plate to 30r / min, the humidity to 50%, and the temperature to 30℃. A copper gel fiber membrane was obtained on the copper mesh and dried at 80℃ for 12h.

[0122] (3) The fiber membrane was calcined in a tube furnace at 400℃ under a nitrogen atmosphere for 2 hours, with a heating rate of 1℃·min. -1 , thus obtaining a fiber membrane.

[0123] (4) Weigh 0.1 g of the above fiber membrane and 0.5376 g of H3BTC (1,3,5-benzenetricarboxylic acid), add them to a 15 mL mixture of ethanol and water in a volume ratio of V / V = 1:1, stir for 10 min, transfer the mixture to a 50 mL Teflon reactor, heat to 110 °C, and react for 8 h. After centrifugation, wash three times with ethanol and water, and dry under vacuum at 80 °C for 12 h to obtain Cu-BTC fiber material, which is used as electrode material.

[0124] The sensitivity of the electrode material obtained in this example was 10.52 μA·mM, obtained by testing using the same method as in Example 1.-1 ·cm -2 .

[0125] Comparative Example 2

[0126] Comparative Example 3 is similar to Comparative Example 1, except that step (1) is: prepare a 10wt% PVA solution, dissolve 0.6g of copper acetate solid in 2ml of deionized water to prepare a copper acetate aqueous solution, and prepare a spinning solution with the PVA solution at a volume ratio of 1:2.5.

[0127] The sensitivity of the electrode material obtained in this example was 216.70 μA·mM, measured using the same method as in Example 1. -1 ·cm -2 .

[0128] This technology innovatively employs electrospinning to prepare copper-based MOF nanofiber membranes, exhibiting excellent fiber morphology. Electrospinning increases the specific surface area of ​​the material, improving its conductivity and sensitivity. This method for synthesizing copper-based MOF nanofiber membranes based on electrospinning technology is original in the field of enzyme-free glucose sensors.

Claims

1. A copper-based MOF nanofiber membrane suitable for use as an electrode material in enzyme-free glucose sensors, characterized in that, Prepared by a method comprising the following steps: (1) A polyvinyl alcohol solution is added to a copper acetate solution to form a spinning solution, wherein the mass fraction of copper acetate in the copper acetate solution is 22.5%~23.5%, the mass fraction of polyvinyl alcohol in the polyvinyl alcohol solution is 10%~12%, and the volume ratio of copper acetate solution to polyvinyl alcohol solution is 1:2.5; (2) Electrospinning the spinning solution to obtain a copper-based nanofiber membrane; (3) The copper-based nanofiber membrane is calcined in air atmosphere to obtain copper oxide fiber membrane, wherein the calcination temperature is 400℃ and the calcination time is 2h; (4) The copper oxide fiber membrane is mixed with an organic ligand, a solvent is added, and a copper-based MOF nanofiber membrane is obtained after hydrothermal reaction. The organic ligand is trimesic acid, the molar ratio of the organic ligand to the copper oxide fiber membrane is (2.0~2.2):1, the solvent is a mixed solution of ethanol and water in a volume ratio of 1:1, the hydrothermal reaction temperature is 110℃, and the reaction time is 10h.

2. The method for preparing the copper-based MOF nanofiber membrane according to claim 1, characterized in that, Includes the following steps: (1) A polyvinyl alcohol solution is added to a copper acetate solution to form a spinning solution, wherein the mass fraction of copper acetate in the copper acetate solution is 22.5%~23.5%, the mass fraction of polyvinyl alcohol in the polyvinyl alcohol solution is 10%~12%, and the volume ratio of copper acetate solution to polyvinyl alcohol solution is 1:2.5; (2) Electrospinning the spinning solution to obtain a copper-based nanofiber membrane; (3) The copper-based nanofiber membrane is calcined in air atmosphere to obtain copper oxide fiber membrane, wherein the calcination temperature is 400℃ and the calcination time is 2h; (4) The copper oxide fiber membrane is mixed with an organic ligand, a solvent is added, and a copper-based MOF nanofiber membrane is obtained after hydrothermal reaction. The organic ligand is trimesic acid, the molar ratio of the organic ligand to the copper oxide fiber membrane is (2.0~2.2):1, the solvent is a mixed solution of ethanol and water in a volume ratio of 1:1, the hydrothermal reaction temperature is 110℃, and the reaction time is 10h.

3. An enzyme-free glucose sensor electrode material, characterized in that, Includes the copper-based MOF nanofiber membrane of claim 1.

4. An enzyme-free glucose sensor electrode, characterized in that, Includes the electrode material described in claim 3.

5. The application of the copper-based MOF nanofiber membrane of claim 1, the enzyme-free glucose sensor electrode material of claim 3, or the enzyme-free glucose sensor electrode of claim 4 in the field of glucose detection.

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