Preparation and application of Fe / Ni carbon-based material derived from core-shell MOFs

Abstract

The invention relates to a core-shell MOFs-derived Fe / Ni carbon-based material, which is prepared by the following method: synthesizing an iron-based MOF-MIL-101 (Fe) by using a hydrothermal method, taking the MIL-101 (Fe) as a core MOF, inducing and growing Ni-MOF outside the core MOF as a shell under the guidance of PVP (Polyvinyl Pyrrolidone), and performing pyrolysis to synthesize the novel core-shell MOFs-derived Fe / Ni carbon-based material. The invention further relates to a preparation method and application of the electrochemical sensor for neurotransmitter detection, the prepared core-shell MOFs derived Fe / Ni carbon-based material is fixed on a carbon paper electrode, the electrochemical sensor is prepared, and the electrochemical sensor is applied to neurotransmitter detection. The Fe / Ni carbon-based material derived from the core-shell MOFs has unique sensing property, and the obtained electrochemical sensor system has the characteristics of high sensitivity, wide detection range, low detection limit, good stability and the like.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical sensors, specifically relating to Fe / Ni carbon-based materials derived from core-shell MOFs for neurotransmitter detection, methods for preparing electrochemical sensors, and their applications. Background Technology

[0002] Neurotransmitters (NTs), as endogenous molecules that act as chemical messengers, participate in neurotransmission between neurons and the regulation of a range of physiological functions. Dopamine (DA) and serotonin (5-HT) are crucial neurotransmitters regulating various physiological and behavioral processes. DA imbalances are associated with physiological and psychological disorders, while 5-HT regulates mood, sleep patterns, appetite, body temperature, and hormonal activity. Imbalances in DA and 5-HT levels are linked to many neurological disorders, including Parkinson's disease, schizophrenia, and depression. Monitoring these two neurotransmitters will contribute to a deeper understanding of the mechanisms underlying animal behavior.

[0003] Various methods for analyzing NTs, such as chromatography, fluorescence, chemiluminescence, and capillary electrophoresis, have been reported. Among them, electrochemical sensing has advantages such as simple operation, low cost, and fast response speed. However, bare electrodes suffer from low sensitivity and poor selectivity, often failing to fully meet the needs of practical applications. Since DA and 5-HT are usually present in biological fluids at ultra-low levels, new materials are needed to construct novel electrochemical sensors for high-sensitivity and selective detection of DA and 5-HT. Currently, conductive elements containing carbon materials, conductive polymers, conductive metal-organic frameworks (MOFs), or metal nanoparticles are commonly used to improve the selectivity, sensitivity, and accuracy of electrochemical sensors. Among them, MOFs are a class of crystalline porous materials with a periodic network structure formed by the self-assembly of inorganic metal centers and bridging organic ligands. They differ from both inorganic porous materials and general organic complexes, combining the rigidity of inorganic materials with the flexibility of organic materials, making them a promising candidate for development in the field of electrochemical sensors. Unfortunately, although MOFs can be used alone as electrode modifications, they suffer from poor stability, weak anti-interference ability, and low sensitivity, making it difficult to meet the needs of determining trace amounts of DA and 5-HT in complex samples. Summary of the Invention

[0004] The first technical problem to be solved by this invention is to prepare a core-shell MOF-derived Fe / Ni carbon-based material. As a porous carbon material, this material partially retains the octahedral carbon framework and disperses Fe3O4 and Ni nanoparticles inside and outside, which is more conducive to electron transport and can effectively improve conductivity.

[0005] The second technical problem to be solved by the present invention is to provide a method for preparing an electrochemical sensor for neurotransmitter detection. The method uses Fe / Ni carbon-based materials derived from core-shell MOFs to modify the electrode. Fe3O4 nanoparticles and Ni nanoparticles each play a role in improving the target catalytic effect, and the synergistic catalytic effect gives the sensor excellent performance and high sensitivity.

[0006] The third technical problem to be solved by this invention is the application of electrochemical sensors for neurotransmitter detection. An electrochemical sensor modified with Fe / Ni carbon-based materials derived from core-shell MOFs is used to prepare a system for detecting neurotransmitters. The system includes a working electrode, a counter electrode, a reference electrode, and an electrolytic cell, which quantitatively measures neurotransmitters and has the advantages of low detection limit, strong anti-interference ability, and high stability.

[0007] To address the first technical problem, this invention provides a core-shell MOF-derived Fe / Ni carbon-based material, which is obtained by pyrolysis of an iron-nickel MOF precursor. The iron-nickel MOF precursor has an iron core layer and a nickel coating layer. The iron core layer is an iron-containing MOF structure, and the nickel coating layer is formed by in-situ reaction and bonded to the nickel-containing MOF structure of the iron core layer.

[0008] Preferably, the iron-nickel MOF precursor is prepared by the following method:

[0009] S1. MIL-101 (Fe) is prepared by reacting ferric salts with terephthalic acid (H2BDC);

[0010] S2. The MIL-101(Fe) prepared in step S1 is activated by polyvinylpyrrolidone (PVP), and then reacted with nickel salt and H2BDC to obtain the iron-nickel MOF precursor.

[0011] Preferably, in step S1, the reaction temperature is 100–120°C, the reaction time is 20–25 h, and the solvent is N,N-dimethylformamide (DMF).

[0012] In this scheme, DMF is used as a solvent to synthesize MOF because DMF can decompose into a small amount of dimethylamine when heated, which can deprotonate the ligands and make it easier to synthesize MOF.

[0013] Preferably, in step S2, the activation reaction is carried out in a solvent with a mass ratio of DMF, water and ethanol of 15:1:1, and the reaction time is 5 to 10 hours.

[0014] Preferably, in step S2, the mass of PVP added in the activation step is 3 to 6 times that of MIL-101(Fe), and the activation time is 5 to 24 hours.

[0015] Preferably, the pyrolysis temperature is 700–900°C, the pyrolysis time is 1–3 h, and the heating rate is 5–10°C / min, to prepare Fe / Ni carbon-based materials derived from core-shell MOFs.

[0016] The material prepared in this scheme has Fe3O4 and Ni nanoparticles dispersed inside and outside the octahedral carbon framework. The Fe3O4 nanoparticles and Ni nanoparticles each play a different role in improving the catalytic effect, and the synergistic catalytic effect gives the material excellent performance.

[0017] Preferably, the particle size of the Fe / Ni carbon-based material derived from the core-shell MOFs is 600–1500 nm.

[0018] The catalytic effect of nanomaterials is closely related to their particle size. In this scheme, the particle size of the Fe / Ni carbon-based material derived from core-shell MOFs should be in the range of 600 to 1500 nm. If the size is too large, it will affect the catalytic effect.

[0019] To address the second technical problem, this invention employs the following method to prepare an electrochemical sensor for neurotransmitter detection, specifically including the following steps: using a carbon paper (CP) electrode as the substrate electrode, after treatment with acetone, ethanol, and water, Fe / Ni carbon-based material derived from core-shell MOFs is drop-coated onto the treated CP electrode, and after drying, an electrochemical sensor for neurotransmitter detection is obtained.

[0020] To address the third technical problem, this invention utilizes the prepared electrochemical sensor for the detection of neurotransmitters.

[0021] Preferably, the electrochemical sensor is applied to neurotransmitter detection, and the specific steps are as follows: In a three-electrode system, an electrochemical sensor modified with Fe / Ni carbon-based material derived from core-shell MOFs is used as the working electrode, and a platinum electrode and an Ag / AgCl electrode are used as the counter electrode and reference electrode, respectively. The neurotransmitter is quantitatively measured by differential pulse voltammetry.

[0022] The present invention has the following beneficial effects:

[0023] 1. The modifying materials used in electrochemical sensors have a great influence on their conductivity. The core-shell MOF-derived Fe / Ni carbon-based material prepared in this invention, as a porous carbon material, partially retains the octahedral carbon framework, and has Fe3O4 and Ni nanoparticles dispersed inside and outside, which is more conducive to electron transport and can effectively improve conductivity.

[0024] 2. An electrochemical sensor was prepared using Fe / Ni carbon-based materials derived from core-shell MOFs. Fe3O4 nanoparticles and Ni nanoparticles each play a different role in improving the target catalytic effect, and the synergistic catalytic effect gives the sensor excellent performance and high sensitivity.

[0025] 3. The electrochemical sensor modified with Fe / Ni carbon-based material derived from the core-shell MOFs of the present invention is used to prepare a system for detecting neurotransmitters and quantitatively determine neurotransmitters. It has the advantages of low detection limit, strong anti-interference ability and high stability. Attached Figure Description

[0026] Figure 1 This is a technical roadmap for the present invention. (A) is the preparation process of Fe / Ni carbon-based materials derived from core-shell MOFs, and (B) is the preparation and application process of electrochemical sensors prepared using Fe / Ni carbon-based materials derived from core-shell MOFs.

[0027] Figure 2 These are scanning electron microscope images of MIL-101(Fe)(A), Ni-MOF(B), MIL-101(Fe)@Ni-MOF(CD) and Fe3O4 / Ni NPs@NPC(EF) prepared in this invention.

[0028] Figure 3 These are transmission electron microscope images of MIL-101(Fe)@Ni-MOF(AB) and Fe3O4 / Ni NPs@NPC(CD).

[0029] Figure 4 This invention characterizes the cyclic voltammetry (A, C), AC impedance (B), and differential pulse voltammetry (D) of different modified electrochemical sensors. The solution used in A and B is 5 mM [Fe(CN)6] in 0.1 MkCl solution. 3- / 4- The solutions used in C were a mixed solution of 100 μM DA and 5-HT; in D, (1) the bare CP electrode and (2) the Fe3O4 / Ni NPs@NPC modified CP electrode were measured in a 0.1 MPB (pH 7.0) solution, and (3) the bare CP electrode, (4) the MIL-101(Fe)@Ni-MOF and (5) the Fe3O4 / Ni NPs@NPC modified CP electrode were measured in a mixed solution containing 100 μM DA and 5-HT.

[0030] Figure 5 These are the current response curves of the electrochemical sensor of the present invention for different concentrations of DA and 5-HT during the detection process, and the working curves of the sensing system.

[0031] Figure 6 These are the results of differential pulse voltammetry tests on the stability, selectivity, and anti-interference capabilities of the electrochemical sensor of this invention. Detailed Implementation

[0032] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The technical solution of the present invention will be further described below with reference to the embodiments. The following embodiments are only used to illustrate the present invention, but do not limit the scope of the present invention in any way.

[0034] Example 1

[0035] 1. Preparation methods of Fe / Ni carbon-based materials derived from core-shell MOFs, such as... Figure 1 As shown in A, the specific steps are as follows:

[0036] (1) Preparation of MIL-101(Fe): Iron-based MOF—MIL-101(Fe) was synthesized by hydrothermal method. Specifically, 5 mmol FeCl3·6H2O (1.35 g) and 2.5 mmol H2BDC (0.412 g) were placed in 15 mL DMF and stirred for 30 minutes until dissolved. The two substances were mixed evenly and placed in a 40 mL stainless steel high-pressure reactor. The temperature was maintained at 110 °C and the reaction was continued for 20 h. After the reaction was completed, the precipitate was centrifuged and washed at 8000 rpm for 5 min, and washed three times each with DMF, water, and ethanol. Finally, the precipitate was dried overnight in a vacuum oven at 60 °C.

[0037] (2) Preparation of core-shell MOFs: Using MIL-101(Fe) as the core MOF, Ni-MOF was induced to grow on its outer shell through PVP guidance to synthesize MIL-101(Fe)@Ni-MOF. Specifically, 0.1 g of orange MIL-101(Fe) powder was placed in a mixed solution of DMF (30 mL), water (2 mL), and ethanol (2 mL), and sonicated for 30 min to mix evenly. Then, 0.4 g of PVP was added and stirred for 12 h to disperse the PVP evenly and activate MIL-101(Fe). Under vigorous stirring, 0.0625 g of H2BDC and 0.09 g of NiCl2·6H2O were added, followed by rapid injection of 1 mL of triethylamine. The mixture was continuously sonicated at room temperature for 8 h. The resulting product was then centrifuged three times with DMF and methanol, respectively. After the precipitate was washed clean, the material was dried overnight in a vacuum drying oven at 60 °C to obtain core-shell MOFs (MIL-101(Fe)@Ni-MOF).

[0038] (3) Preparation of porous carbon composite material: Fe / Ni carbon-based material derived from core-shell MOFs is formed by pyrolysis. Specifically, MIL-101(Fe)@Ni-MOF is placed in a corundum ceramic boat and placed in the middle of a tube furnace. The heating rate is set to 5℃min-1 and heated to 800℃. The temperature is maintained at 800℃ for 2h. After the tube furnace cools naturally to room temperature, the product is collected to obtain porous carbon composite material (Fe3O4 / Ni NPs@NPC).

[0039] 2. Preparation method of electrochemical sensor for neurotransmitter detection, such as... Figure 1 As shown in B, the specific steps are as follows:

[0040] (1) Cut CP into pieces with an area of ​​1×1cm. 2 The sample was sized and then ultrasonically treated with acetone, ethanol, and water for 30 minutes in sequence, and then dried for later use.

[0041] (2) CP was modified under heating at 60℃, and 2 mg mL of the solution was prepared using a 1:1 mixture of ultrapure water and anhydrous ethanol. -1 Fe3O4 / Ni NPs@NPC solution.

[0042] (3) Use a pipette to transfer 50 μL of the above solution and drop it onto CP. After drying, the Fe3O4 / Ni NPs@NPC / CP electrochemical sensor is ready for use.

[0043] Experimental Example 1: Morphology and Microstructure

[0044] The MIL-101(Fe), MIL-101(Fe)@Ni-MOF, and Fe3O4 / Ni NPs@NPC in Example 1 were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results are as follows: Figure 2 and Figure 3 As shown.

[0045] in, Figure 2 A is a SEM image of MIL-101(Fe). Figure 2 B is the SEM image of Ni-MOF. Figure 2 CD is the SEM image of MIL-101(Fe)@Ni-MOF. Figure 2 EF is the SEM image of Fe3O4 / Ni NPs@NPC. Figure 3 AB are TEM images of MIL-101(Fe)@Ni-MOF. Figure 3 CD is a TEM image of Fe3O4 / Ni NPs@NPC.

[0046] Regarding the above structural changes Figure 2AD demonstrates that the shell Ni-MOF was successfully coated on the surface of the core MIL-101(Fe), i.e., the successful preparation of MIL-101(Fe)@Ni-MOF. Figure 2 EF indicates that the pyrolyzed Fe3O4 / Ni NPs@NPC can partially retain the octahedral configuration of MIL-101(Fe)@Ni-MOF and is doped with nanoparticles. Figure 3 AB also demonstrated the successful preparation of MIL-101(Fe)@Ni-MOF. Figure 3 CD proved that Fe3O4 / Ni NPs@NPC pyrolysis did indeed yield two types of nanoparticles: Fe3O4NPs and NiNPs.

[0047] Example 2: Performance Evaluation of Electrochemical Sensors

[0048] The performance of electrochemical sensors modified with different materials was characterized using cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The results are as follows: Figure 4 As shown.

[0049] in, Figure 4 A is a cyclic voltammetry diagram. Figure 4 B is the AC impedance diagram. The solution used in both diagrams is 5mM [Fe(CN)6] in 0.1M KCl. 3- / 4- The solution used bare CP, Fe@PC, Ni@PC, and Fe3O4 / Ni NPs@NPC / CP as electrodes. Fe@PC and Ni@PC were obtained by pyrolysis of MIL-101(Fe) and Ni-MOF at 800℃ for 2 hours, respectively. Experimental results show that, compared to electrochemical sensors prepared with other modified materials, the electrochemical sensor modified with the Fe / Ni carbon-based material derived from core-shell MOFs described in this invention exhibits a stronger current response.

[0050] Figure 4 C represents the cyclic voltammogram. The solution used in the figure is a 100 μM mixed solution of DA and 5-HT. The electrodes used are bare CP, Fe@PC, Ni@PC, and Fe3O4 / Ni NPs@NPC / CP. Experimental results show that, compared with electrochemical sensors prepared with other modified materials, the electrochemical sensor modified with the core-shell MOF-derived Fe / Ni carbon-based material described in this invention exhibits stronger response to DA and 5-HT currents, higher detection sensitivity, and better detection performance.

[0051] Figure 4 D is the differential pulse voltammogram, using the following electrodes and test solutions:

[0052] (1) Bare CP electrode, 0.1M PB (pH 7.0) solution;

[0053] (2) Fe3O4 / Ni NPs@NPC / CP electrode, 0.1M PB (pH 7.0) solution;

[0054] (3) Bare CP electrode, 100 μM mixed solution of DA and 5-HT;

[0055] (4) MIL-101(Fe)@Ni-MOF modified electrode, 100 μM mixed solution of DA and 5-HT;

[0056] (5) Fe3O4 / Ni NPs@NPC / CP electrode, 100 μM mixed solution of DA and 5-HT.

[0057] Figure 4 The results from D showed that neither the bare electrode nor the Fe3O4 / Ni NPs@NPC modified electrode had a detection signal in the PB solution, indicating that the material itself does not affect the detection of the target analyte. Detection of the bare electrode and the modified electrode in a mixed solution of DA and 5-HT demonstrated that the prepared Fe3O4 / Ni NPs@NPC material can effectively separate the two analytes and improve their detection sensitivity.

[0058] Experimental Example 3, Example 1: Sensing Performance of Electrochemical Sensor for Detecting DA and 5-HT

[0059] In this experimental example, the sensing performance was tested using a three-electrode system. The modified electrochemical sensor of this invention was used as the working electrode, a platinum wire as the counter electrode, and Ag / AgCl as the reference electrode. The sensor was tested in 0.1 M PB electrolyte solution at 100 mV·s⁻¹. -1 Differential pulse voltammetry was used to test the sensor at a scan rate in the range of 0 to 0.6 V, and the voltammetric response signal of the sensor was recorded. The corresponding oxidation peak current was recorded by measuring standard solutions of DA and 5-HT at different concentrations, and a standard curve was plotted using peak current-concentration.

[0060] like Figure 5 As shown in AE, DA and 5-HT exhibit a non-linear growth trend in the range of 0.5 μM to 1 mM, but at low concentrations, they show a linear growth trend. Specifically:

[0061] like Figure 5 As shown in B, the nonlinear regression equation of DA is fitted as: I DA =172.95+(-174.56) / (1+(C DA / 251.17)^0.7173)(R 2 =0.994);

[0062] like Figure 5 As shown in C, the linear regression equation of DA is fitted as: (1)I DA=1.364C DA +0.055(R 2 =0.998); (2)I DA =0.318C DA +22.421(R 2 =0.986).

[0063] like Figure 5 As shown in D, the nonlinear regression equation of 5-HT is fitted as: I 5-HT =99.93+(-100.16) / (1+(C 5-HT / 153.57)^0.8196)(R 2 =0.988);

[0064] like Figure 5 As shown in E, the linear regression equation of 5-HT is fitted as: (1)I 5-HT =0.653C 5-HT +0.109(R 2 =0.981); (2)I 5-HT =0.134C 5-HT +27.905(R 2 =0.991).

[0065] The detection limit for DA was 0.165 μM, and the detection limit for 5-HT was 0.327 μM. Example 3 demonstrates that this electrochemical sensor exhibits high sensitivity for the determination of DA and 5-HT standard solutions.

[0066] Experimental Example 4, Example 1: Repeatability, stability, selectivity, and anti-interference of electrochemical sensor for detecting DA and 5-HT.

[0067] 1. Repetitiveness

[0068] To investigate the repeatability of the electrochemical sensor of this invention, six repeated measurements of 100 μM DA and 5-HT were performed using the same sensor, with relative standard deviations of 1.64% and 1.60% for the current response. Reproducibility tests were conducted using six independent sensors to detect DA and 5-HT, with relative standard deviations of 2.69% and 3.58%, respectively, indicating that the electrochemical sensor of this invention has good repeatability.

[0069] 2. Stability

[0070] To investigate the stability of the electrochemical sensor, the changes in its volt-ampere response were measured after storage at room temperature for 1, 2, 3, 4, and 5 weeks. Figure 6 As shown in Figure A, the signal values ​​of the two target substances, DA and 5-HT, remained stable at the same position, indicating that the electrochemical sensor of this invention has good stability.

[0071] 3. Selectivity and anti-interference ability

[0072] All experiments were conducted in a 100 μM mixed solution of DA and 5-HT, using sodium ions (Na+) as the preferred ion. + ), potassium ions (K) + ), chloride ions (Cl) - ), nitrate ions (NO3) - Ascorbic acid (AA), D-glutamic acid (D-Glu), L-tyrosine (L-Tyr), L-cysteine ​​(L-Cys), and glucose were used as interfering agents for performance verification.

[0073] like Figure 6 As shown in Figure B, when the concentration of other interfering substances was 100 μM, no peak values ​​were detected at the potential locations of the two target substances, DA and 5-HT. Figure 6 As shown in Figure C, when other interfering substances were at 10 times the concentration of the target analyte (1 mM), the test results showed no substantial interference with the detection of the target analyte, and the signal values ​​fluctuated within an acceptable range. Therefore, this electrochemical sensor can distinguish DA at 5-HT from other interfering substances in solution, demonstrating that the electrochemical sensor of this invention has good anti-interference and selectivity.

[0074] Experimental Example 5, Example 1: Determination of DA and 5-HT in serum samples using an electrochemical sensor.

[0075] To evaluate the detection performance of the electrochemical sensor for DA and 5-HT in serum samples, the recovery rate of serum samples from healthy individuals was determined using the standard addition method. Based on the linear equation obtained in Experimental Example 3, the concentrations of DA and 5-HT in the human serum could be determined, thus achieving quantitative detection. The results are shown in Table 1. When the added amounts of DA and 5-HT were 10 μM, 20 μM, 50 μM, 100 μM, and 150 μM, respectively, the spiked recovery rate of DA ranged from 98.26% to 102.7%, and the spiked recovery rate of 5-HT ranged from 98.02% to 103.03%. These results indicate that the invention has good accuracy and potential for application in clinical diagnosis.

[0076] Table 1. Determination results of DA and 5-HT in human serum samples using the electrochemical sensor of the present invention.

[0077]

[0078]

[0079] a The symbol "-" means "not detected".

[0080] Experimental Example 6, Example 1: Determination of DA in Cell Secretion Fluid Samples using Electrochemical Sensors

[0081] To further investigate the applicability of the electrochemical sensor for DA detection, we cultured and stimulated PC-12 cells to study the accuracy of this invention in detecting DA in cell supernatant, and performed corresponding spiking tests. The results are shown in Table 2. The results indicate that the spiked detection values ​​conform to the linear curve we plotted, and the DA recovery rate ranged from 98.06% to 10819%. Therefore, this invention demonstrates good accuracy and reliability and holds promise for the detection of DA in real cell samples.

[0082] Table 2. Measurement results of DA by the electrochemical sensor of the present invention in cell supernatant.

[0083]

[0084] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A Fe / Ni carbon-based material derived from core-shell MOFs, characterized in that, It is obtained by pyrolysis of an iron-nickel MOF precursor, which has an iron core layer and a nickel coating layer. The iron core layer is an iron-containing MOF structure, and the nickel coating layer is an in-situ reaction bonded to the nickel-containing MOF structure of the iron core layer.

2. The Fe / Ni carbon-based material derived from core-shell MOFs according to claim 1, characterized in that, The iron-nickel MOF precursor was prepared by the following method: S1. MIL-101 (Fe) is prepared by reacting ferric salts with terephthalic acid (H2BDC); S2. The MIL-101(Fe) prepared in step S1 is activated by polyvinylpyrrolidone (PVP), and then reacted with nickel salt and H2BDC to obtain the iron-nickel MOF precursor.

3. The Fe / Ni carbon-based material derived from core-shell MOFs as described in claim 2, characterized in that: In step S1, the reaction temperature is 100–120°C, the reaction time is 20–25 h, and the solvent is N,N-dimethylformamide (DMF).

4. The Fe / Ni carbon-based material derived from core-shell MOFs as described in claim 2, characterized in that: In step S2, the activation reaction is carried out in a solvent of DMF, water and ethanol in a mass ratio of 15:1:1 for 5 to 10 hours.

5. The Fe / Ni carbon-based material derived from core-shell MOFs according to claim 2, characterized in that: In step S2, the mass of PVP added in the activation step is 3 to 6 times that of MIL-101(Fe), and the activation time is 5 to 24 hours.

6. The Fe / Ni carbon-based material derived from core-shell MOFs as described in claim 1, characterized in that: The pyrolysis temperature is 700–900℃, the pyrolysis time is 1–3 h, and the heating rate is 5–10℃ / min, to prepare Fe / Ni carbon-based materials derived from core-shell MOFs.

7. The Fe / Ni carbon-based material derived from core-shell MOFs according to claim 1, characterized in that, The core-shell MOFs-derived Fe / Ni carbon-based materials have a particle size of 600–1500 nm.

8. A method for preparing an electrochemical sensor for neurotransmitter detection using Fe / Ni carbon-based materials derived from core-shell MOFs prepared according to claim 1, characterized in that, The process includes the following steps: using a carbon paper (CP) electrode as the substrate electrode, after treatment with acetone, ethanol and water, Fe / Ni carbon-based material derived from core-shell MOFs is drop-coated onto the treated CP electrode, and after drying, an electrochemical sensor for neurotransmitter detection is obtained.

9. An application of the electrochemical sensor for neurotransmitter detection prepared as claimed in claim 8, characterized in that, Used for the detection of neurotransmitters.

10. An application of the electrochemical sensor for neurotransmitter detection as described in claim 9, characterized in that, In the three-electrode system, an electrochemical sensor modified with Fe / Ni carbon-based material derived from core-shell MOFs was used as the working electrode, and a platinum electrode and an Ag / AgCl electrode were used as the counter electrode and reference electrode, respectively. Differential pulse voltammetry was used to quantitatively determine neurotransmitters.

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