A ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode, its preparation method, and its application.

Abstract

This invention belongs to the field of nanomaterial preparation technology and discloses a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode, its preparation method, and its application. The method includes the following steps: soluble cobalt salt and 2-methylimidazole are dissolved in water and mixed to form solution C; carbon is arranged in solution C and reacted to obtain a ZIF / CC precursor; a selenium source and a nitrogen source are sequentially added to water to form solution D; solution D and the ZIF / CC precursor are placed in a reactor and reacted via DBD micro-plasma to obtain the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode. The ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode material prepared by this invention reacts at room temperature and atmospheric pressure using an 80V voltage for only 60 minutes; CoSe nanoparticles can effectively prevent the aggregation of nitrogen-doped polymer carbon dots, and the target material is directly grown and synthesized on carbon cloth, improving conductivity and stability.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode, its preparation method, and its application. Background Technology

[0002] Carbon dots (CDs) exhibit satisfactory electrochemical sensing performance in carbon nanomaterials due to their advantages such as low cost, simple synthesis, high conductivity, good biocompatibility, and good chemical stability. For example, Wu et al. (Anal. Chim. Acta 2022, 1229, 340365) designed a carbon dot-enhanced laccase electrochemical sensor, which can serve as an immobilization substrate for laccase, improving its electron transfer efficiency and achieving highly sensitive detection of dopamine. Jiang et al. (J. Colloid Interf. Sci. 2015, 452, 199-202.) prepared a novel nitrogen-doped carbon dots (NCDs) using microwave-assisted technology. These NCDs have abundant hydroxyl and amino groups on their surface and can be used for the direct electrochemical detection of trace amounts of dopamine in human serum and urine samples. Currently reported methods for synthesizing CDs include electrolysis, solvothermal methods, acid etching, chemical synthesis, and high-temperature pyrolysis. However, most of these methods suffer from problems such as easy agglomeration of carbon dots, difficulty in purification, complex synthesis steps, high energy consumption, and long reaction times. Therefore, it is urgent to select appropriate strategies to solve these problems in CD synthesis.

[0003] Transition metal selenides possess a unique electronic structure (4s 4p), with selenium atoms having empty 3d orbitals and energy levels close to the 3s and 3p orbitals. This endows transition metal selenides with more metallic properties, exhibiting excellent electron transfer capabilities that help accelerate electrochemical reactions. Their excellent conductivity and electrocatalytic activity make them widely used in energy storage, sensors, and water splitting, among other fields. Studies have shown that combining transition metal selenides with carbon nanomaterials can significantly enhance the conductivity of the materials. However, carbon nanomaterials generally require external addition or stepwise composite methods, which are cumbersome and time-consuming. In recent years, there have been reports of one-step synthesis of transition metal selenide / carbon nanocomposites using organic framework materials (MOFs) as precursors through high-temperature pyrolysis followed by selenization, but most of these methods employ time-consuming hydrothermal / solvothermal or electrochemical methods, resulting in high energy consumption. Therefore, exploring a rapid, energy-saving, and environmentally friendly method for preparing transition metal selenide@carbon nanocomposite electrode materials is of great significance. Summary of the Invention

[0004] The purpose of this invention is to address the problems of complex operation and high energy consumption in the preparation of existing transition metal selenide@carbon nanocomposites, and to provide a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode (CoSe@NPCDs / CC), its preparation method, and applications. This invention utilizes DBD microplasma to rapidly prepare ZIF-derived CoSe@NPCDs / CC self-supporting electrode material on CC in a one-step process at room temperature and ambient pressure. Free radicals and solvated electrons (eaq-) generated by microplasma-liquid interaction break down ZIF to form hydrocarbons and Co. 2+ Under normal pressure and low temperature, a chemical reaction occurs, accelerating the generation of CoSe@NPCDs nanoparticles, forming a uniform CoSe@NPCDs nanosphere morphology, and further selenization to form the target material; CoSe nanoparticles can effectively prevent the aggregation of NPCDs, and the target material grows directly on CC in situ, reducing the use of binders and improving the conductivity and stability of the material. CoSe@NPCDs / CC, as a self-supporting sensing electrode, exhibits the advantages of high sensitivity, stability and high selectivity for DA detection.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] The first objective of this invention is to provide a method for preparing a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode, comprising the following steps:

[0007] S1. Dissolve soluble cobalt salt and 2-methylimidazole in water to form solution A and solution B, then mix solution A and solution B to form solution C. Arrange the treated carbon in solution C to react and obtain the ZIF / CC precursor.

[0008] S2. Selenium source and nitrogen source are added to water in sequence to form solution D. Solution D and ZIF / CC precursor are mixed and placed in DBD microplasma reactor for DBD microplasma reaction. After the reaction is completed, the solution is washed and dried to obtain ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode.

[0009] Preferably, in S1, the mass-to-volume ratio of the soluble cobalt salt to water is 1.164 g: 80 mL, and the soluble cobalt salt is Co(NO3)2·6H2O; the mass-to-volume ratio of the 2-methylimidazole to water is 2.627 g: 40 mL.

[0010] Preferably, in S1, the volume ratio of solution A to solution B is 2:1.

[0011] Preferably, in S1, the carbon cloth is treated by immersing it in 8 mol / L nitric acid at 90°C for 1 hour, then washing it with ethanol and water in sequence, and finally drying it at 60°C for 6 hours.

[0012] Preferably, in S1, the ratio of the carbon cloth to solution C is 1 × 3 cm⁻¹. 2 120 mL, reaction time 12 h.

[0013] Preferably, in S2, the mass-to-volume ratio of the selenium source, nitrogen source, and water is 20 mg: 0.5 mL: 5 mL; the selenium source is one of selenium powder, selenium dioxide, or sodium selenite, and the nitrogen source is one of hydrazine hydrate, ethylenediamine, urea, or ammonia.

[0014] Preferably, in S2, the ratio of the ZIF / CC precursor to solution D is 1 × 3 cm⁻¹. 2 5mL.

[0015] Preferably, in S2, the voltage of the DBD microplasma reaction is 40-100V and the time is 50-100min.

[0016] A second objective of this invention is to provide a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode prepared according to the above-described preparation method.

[0017] A third objective of this invention is to provide the application of ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrodes in the detection of dopamine.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. This invention is the first to utilize dielectric barrier discharge (DBD) microplasma to rapidly prepare ZIF-derived CoSe@NPCDs / CC in situ on carbon cloth (CC) in a one-step process at room temperature and pressure. Dielectric barrier discharge (DBD) microplasma is a type of plasma with advantages such as small physical size, high electron density, and stable operation at room temperature and pressure. The free radicals and solvated electrons (eaq-) generated by the microplasma-liquid interaction destroy ZIF to form hydrocarbons and Co. 2+ A chemical reaction occurs at ambient pressure and low temperature, accelerating the generation of CoSe@NPCDs nanoparticles to form a uniform CoSe@NPCDs nanosphere morphology. Further selenization then forms the target material. This method eliminates the need for any binder, effectively solving the carbon dot aggregation problem and improving conductivity. The method is simple; a ZIF-derived CoSe@NPCDs / CC self-supporting electrode is obtained in just 60 minutes at room temperature and pressure using an 80V voltage.

[0020] 2. This invention effectively prevents the aggregation of NPCDs by using CoSe nanoparticles. The target material is grown directly on CC in situ, reducing the use of binders and improving conductivity and stability. Under the test conditions of pH=7.4, the large specific surface area of ​​CoSe@NPCDs and the abundant amino, hydroxyl and carboxyl groups on the surface can bind to (dopamine)DA through electrostatic attraction and hydrogen bonding, which significantly improves the electrocatalytic performance for DA. Therefore, CoSe@NPCDs / CC, as a self-supporting sensing electrode, exhibits the advantages of high sensitivity, stability and high selectivity for the detection of DA, and has been successfully applied to the detection of real human serum samples. Attached Figure Description

[0021] Figure 1 A process flow diagram for preparing ZIF-derived CoSe@NPCDs / CC self-supporting electrodes according to the present invention;

[0022] Figure 2 This is the X-ray diffraction pattern of CoSe@NPCDs / CC in Embodiment 1 of the present invention;

[0023] Figure 3 This is the X-ray diffraction pattern of CoSe@NPCDs powder in Example 1 of the present invention;

[0024] Figure 4 These are scanning electron microscope images of Example 1 CoSe@NPCDs / CC and Comparative Example 1 ZIF / CC of the present invention;

[0025] Figure 5 This is a transmission electron microscope image of CoSe@NPCDs from Embodiment 1 of the present invention;

[0026] Figure 6 Example 1, CoSe@NPCDs / CC, and Comparative Example 1, ZIF / CC, were prepared in 0.1M PBS (pH = 7.4) at 50 mV for s. -1 Cyclic voltammetry (CV) curves at scan rates with and without DA and with 1 mM DA. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0029] This invention prepares a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode using a DBD microplasma method. This method utilizes a plasma with advantages such as small physical size, high electron density, and stable operation at room temperature and pressure. Free radicals and solvated electrons (eaq-) generated by the microplasma-liquid interaction disrupt ZIF, forming hydrocarbons and Co. 2+ A chemical reaction occurs at ambient pressure and low temperature, accelerating the generation of CoSe@NPCDs nanoparticles and forming uniform CoSe@NPCDs nanospheres. Further selenization then forms the target material, eliminating the need for any binders and effectively solving the carbon dot aggregation problem, thus improving conductivity. The method is simple, requiring only 60 minutes of reaction at 80V under room temperature and pressure to rapidly prepare a ZIF-derived CoSe@NPCDs / C self-supporting electrode in situ on a C substrate. The unique electronic structure of CoSe nanoparticles (4s 4p) and the presence of empty 3d orbitals in selenium atoms, with energy levels close to the 3s and 3p orbitals, endow transition metal selenides with more metallic properties and excellent electron transfer capabilities, facilitating faster electrochemical reactions and effectively preventing NPCDs aggregation. The target material grows directly in situ on the C substrate, reducing the use of binders and improving conductivity and stability. Specific examples are provided below for illustration.

[0030] Example 1

[0031] A method for fabricating a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode, the fabrication process is as follows: Figure 1 As shown, it includes the following steps:

[0032] S1, CC pretreatment: 1×3cm 2 Carbon cloth (CC) was immersed in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water in sequence and dried at 60°C for 6 h to obtain the treated CC.

[0033] Weigh 1.164g of Co(NO3)2·6H2O and dissolve it in 80mL of deionized water to form solution A; weigh 2.627g of 2-methylimidazole and dissolve it in 40mL of deionized water to form solution B;

[0034] Then, solutions A and B were mixed to form a purple solution (solution C). The treated CC was placed in solution C and reacted at room temperature for 12 hours. After the reaction was completed, the solution was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain the ZIF / CC precursor.

[0035] S2. Weigh 20 mg of selenium dioxide (SeO2) and 0.5 mL of hydrazine hydrate, add 5 mL of deionized water to form solution D. Mix solution D with the ZIF / CC precursor and place it in a dielectric barrier (DBD) microplasma reactor for DBDDBD microplasma reaction. The voltage is 80 V and the reaction time is 60 min. After the reaction, wash the sample three times with ethanol and deionized water alternately, and dry it overnight at 60 °C to obtain ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode (CoSe@NPCDs / CC).

[0036] Example 2

[0037] A method for fabricating a ZIF-derived CoSe@NPCDs / CC self-supporting electrode includes the following steps:

[0038] S1, CC pretreatment: 1×3cm 2 CC was immersed in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water in sequence and dried at 60°C for 6 h to obtain the treated CC;

[0039] Weigh 1.164g of Co(NO3)2·6H2O and dissolve it in 80mL of deionized water to form solution A; weigh 2.627g of 2-methylimidazole and dissolve it in 40mL of deionized water to form solution B;

[0040] Then, solutions A and B were mixed to form solution C. The treated CC was placed in solution C and reacted at room temperature for 12 hours. After the reaction was completed, the solution was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain the ZIF / CC precursor.

[0041] S2. Weigh 20 mg of selenium powder (Se) and 0.5 mL of hydrazine hydrate, add 5 mL of deionized water to form solution D. Mix solution D with the ZIF / CC precursor and place it in a DBD microplasma reactor to carry out the DBD-BD microplasma reaction. The reaction voltage is 40 V and the reaction time is 100 min. After the reaction, wash the sample three times with ethanol and deionized water alternately, and dry it overnight at 60 °C to obtain the CoSe@NPCDs / CC self-supporting electrode.

[0042] Experiments show that the characterization data of the CoSe@NPCDs / CC self-supporting electrode obtained in this embodiment are not substantially different from those in Example 1.

[0043] Example 3

[0044] A method for fabricating a ZIF-derived CoSe@NPCDs / CC self-supporting electrode includes the following steps:

[0045] S1, CC pretreatment: 1×3cm 2 CC was immersed in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water in sequence and dried at 60°C for 6 h to obtain the treated CC;

[0046] Weigh 1.164g of Co(NO3)2·6H2O and dissolve it in 80mL of deionized water to form solution A; weigh 2.627g of 2-methylimidazole and dissolve it in 40mL of deionized water to form solution B;

[0047] Then, solutions A and B were mixed to form solution C. The treated CC was placed in solution C and reacted at room temperature for 12 hours. After the reaction was completed, the solution was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain the ZIF / CC precursor.

[0048] S2. Weigh 20 mg of sodium selenite and 0.5 mL of hydrazine hydrate, add 5 mL of deionized water to form solution D. Mix solution D with the ZIF / CC precursor and place it in a DBD microplasma reactor to carry out the DBD-BD microplasma reaction. The reaction voltage is 100 V and the reaction time is 40 min. After the reaction, wash the sample three times with ethanol and deionized water alternately, and dry it overnight at 60 °C to obtain the CoSe@NPCDs / CC self-supporting electrode.

[0049] Experiments show that the characterization data of the CoSe@NPCDs / CC self-supporting electrode obtained in this embodiment are not substantially different from those in Example 1.

[0050] Example 4

[0051] A method for fabricating a ZIF-derived CoSe@NPCDs / CC self-supporting electrode includes the following steps:

[0052] S1, CC pretreatment: 1×3cm 2 CC was immersed in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water in sequence and dried at 60°C for 6 h to obtain the treated CC;

[0053] Weigh 1.164g of Co(NO3)2·6H2O and dissolve it in 80mL of deionized water to form solution A; weigh 2.627g of 2-methylimidazole and dissolve it in 40mL of deionized water to form solution B;

[0054] Then, solutions A and B were mixed to form solution C. The treated CC was placed in solution C and reacted at room temperature for 12 hours. After the reaction was completed, the solution was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain the ZIF / CC precursor.

[0055] S2. Weigh 20 mg of selenium powder and 0.5 mL of urea, add 5 mL of deionized water to form solution D. Mix solution D with the ZIF / CC precursor and place it in a DBD microplasma reactor to carry out the DBD-BD microplasma reaction. The reaction voltage is 100 V and the reaction time is 40 min. After the reaction, wash the sample three times with ethanol and deionized water alternately, and dry it overnight at 60 °C to obtain the CoSe@NPCDs / CC self-supporting electrode.

[0056] Experiments show that the characterization data of the CoSe@NPCDs / CC self-supporting electrode obtained in this embodiment are not substantially different from those in Example 1.

[0057] Example 5

[0058] A method for fabricating a ZIF-derived CoSe@NPCDs / CC self-supporting electrode includes the following steps:

[0059] S1, CC pretreatment: 1×3cm 2 CC was immersed in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water in sequence and dried at 60°C for 6 h to obtain the treated CC;

[0060] Weigh 1.164g of Co(NO3)2·6H2O and dissolve it in 80mL of deionized water to form solution A; weigh 2.627g of 2-methylimidazole and dissolve it in 40mL of deionized water to form solution B;

[0061] Then, solutions A and B were mixed to form solution C. The treated CC was placed in solution C and reacted at room temperature for 12 hours. After the reaction was completed, the solution was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain the ZIF / CC precursor.

[0062] S2. Weigh 20 mg of selenium powder and 0.5 mL of ethylenediamine, add 5 mL of deionized water to form solution D. Mix solution D with the ZIF / CC precursor and place it in a DBD microplasma reactor to carry out the DBD-BD microplasma reaction. The reaction voltage is 80 V and the reaction time is 60 min. After the reaction, wash the sample three times with ethanol and deionized water alternately, and dry it overnight at 60 °C to obtain the CoSe@NPCDs / CC self-supporting electrode.

[0063] Experiments show that the characterization data of the CoSe@NPCDs / CC self-supporting electrode obtained in this embodiment are not substantially different from those in Example 1.

[0064] Example 6

[0065] A method for fabricating a ZIF-derived CoSe@NPCDs / CC self-supporting electrode includes the following steps:

[0066] S1, CC pretreatment: 1×3cm 2 CC was immersed in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water in sequence and dried at 60°C for 6 h to obtain the treated CC;

[0067] Weigh 1.164g of Co(NO3)2·6H2O and dissolve it in 80mL of deionized water to form solution A; weigh 2.627g of 2-methylimidazole and dissolve it in 40mL of deionized water to form solution B;

[0068] Then, solutions A and B were mixed to form solution C. The treated CC was placed in solution C and reacted at room temperature for 12 hours. After the reaction was completed, the solution was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain the ZIF / CC precursor.

[0069] S2. Weigh 20 mg of sodium selenite and 0.5 mL of urea, add 5 mL of deionized water to form solution D. Mix solution D with the ZIF / CC precursor and place it in a DBD microplasma reactor to carry out the DBD-BD microplasma reaction. The reaction voltage is 50 V and the reaction time is 60 min. After the reaction, wash the sample three times with ethanol and deionized water alternately, and dry it overnight at 60 °C to obtain the CoSe@NPCDs / CC self-supporting electrode.

[0070] Experiments show that the characterization data of the CoSe@NPCDs / CC self-supporting electrode obtained in this embodiment are not substantially different from those in Example 1.

[0071] Comparative Example 1

[0072] A method for preparing ZIF / CC includes the following steps:

[0073] CC pretreatment: 1×3cm 2CC was soaked in 8 mol / L nitric acid at 90°C for 1 h, then washed with ethanol and water sequentially, and dried at 60°C for 6 h to obtain the treated CC; 1.164 g of Co(NO3)2·6H2O was weighed and dissolved in 80 mL of deionized water to form solution A; 2.627 g of 2-methylimidazole was weighed and dissolved in 40 mL of deionized water to form solution B; then solutions A and B were mixed to form solution C, and the treated CC was placed in solution C and reacted at room temperature for 12 h. After the reaction, it was washed three times alternately with ethanol and deionized water, and dried at 60°C overnight to obtain ZIF / CC.

[0074] Figure 2 This is the X-ray diffraction (XRD) pattern of CoSe@NPCDs / CC in Embodiment 1 of the present invention. Figure 2 As shown, the main diffraction peaks of CoSe@NPCDs / CC are located at 33.2°, 33.9°, 44.8°, 50.4° and 66.7°, which belong to the (101), (002), (102), (110) and (201) crystal planes of CoSe, respectively. Figure 3 The XRD pattern of CoSe@NPCDs powder in Example 1 of this invention shows a broad peak at 24.5°, which may be related to the highly cross-linked polymer backbone, proving the successful preparation of NPCDs.

[0075] Figure 4 These are scanning electron microscope (SEM) images of the CoSe@NPCDs / CC self-supporting electrode of Example 1 and the precursor of Comparative Example 1 ZIF / CC of the present invention. Figure 4 In the table, a represents ZIF / CC, and b represents CoSe@NPCDs / CC. For example... Figure 4 As shown in Figure a, the SEM image of the precursor comparative example 1 ZIF / CC confirms that the sheet-like ZIF structure grows uniformly on CC, and after the DBD micro-plasma reaction, as... Figure 4 As shown in Figure b (Example 1), the original sheet-like morphology was completely destroyed, transforming into a uniform CoSe@NPCDs nanosphere morphology. This may be due to the free radicals and solvated electrons (eaq-) generated by micro-plasma-liquid interactions destroying ZIF to form hydrocarbons and Co. 2+ Furthermore, selenization is carried out to form the target material, which can effectively solve the problem of carbon dot aggregation and improve conductivity. The method of this invention is simple, and the reaction only takes 60 minutes at room temperature and pressure using 80V voltage to obtain a self-supporting electrode derived from ZIF, which is rapidly prepared in situ on CC in one step.

[0076] TEM images further confirmed the nanosphere morphology of CoSe@NPCDs. Figure 5These are transmission electron microscope (TEM) images of the CoSe@NPCDs self-supporting electrode from Embodiment 1 of the present invention at different magnifications. Figure 5 In the diagram, a and b represent CoSe@NPCDs at different scales, c is the HRTEM plot, and d is the SAED plot. From... Figure 5 As can be seen from this, the diameter of the CoSe@NPCDs nanospheres in Example 1 is approximately 159 nm. Figure 5 b. High-resolution TEM (HRTEM) shows the presence of NPCDs particles (indicated by dashed circles). Figure 5 The lattice spacing of c is 0.296 nm, corresponding to the (101) crystal plane of CoSe. Selected area electron diffraction (SAED) pattern ( Figure 5 d) further confirms the presence of the (101) lattice plane of CoSe. However, no lattice planes associated with carbon points were observed. Figure 5 c) This proves that the carbon dots synthesized in this work are amorphous polymeric carbon dots. In summary, we successfully prepared CoSe@NPCDs / CC in a rapid, one-step process using DBD microplasma at room temperature and pressure. The NPCDs were uniformly dispersed in the CoSe nanospheres without any binder, which effectively solved the carbon dot aggregation problem and improved the conductivity.

[0077] Example 1 CoSe@NPCDs / CC and precursor Comparative Example 1 ZIF / CC were used as self-supporting electrodes for the electrochemical detection of dopamine (DA).

[0078] In the classic three-electrode system, CoSe@NPCDs / CC self-supporting electrodes and ZIF / CC self-supporting electrodes (0.04cm) were used respectively. -2 The loading capacity was 1.1 mg / cm³. 2 The electrode is a working electrode, a carbon rod is a counter electrode, an Ag / AgCl electrode is a reference electrode, and the electrolyte is a 0.1M PBS buffer solution.

[0079] Figure 6 Example 1 of the present invention, CoSe@NPCDs / CC, and the precursor comparative example 1, ZIF / CC, were prepared in 0.1M PBS (pH=7.4) at 50mV s. -1 Cyclic voltammetry (CV) curves at scan rates with and without DA (dissolved ionomer) and with 20 μL 1 mM DA. Figure 6 As shown, CoSe@NPCDs / CC exhibits superior catalytic activity for DA oxidation compared to ZIF / CC. This is likely because the functional groups on the NPCDs surface form electrostatic attraction and hydrogen bonds with DA molecules, enhancing the catalytic activity of DA. These results demonstrate that CoSe@NPCDs / CC possesses significant electrochemical sensing performance for DA and holds promise as a low-cost alternative electrode for high-performance DA detection.

[0080] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the implementation examples, preferred implementation examples are described here to avoid redundancy. Although preferred implementation examples of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these implementation examples. Therefore, the appended claims are intended to be interpreted as including the preferred implementation examples as well as all changes and modifications falling within the scope of this invention.

[0081] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode, characterized in that, Includes the following steps: S1. Dissolve soluble cobalt salt and 2-methylimidazole in water to form solution A and solution B, then mix solution A and solution B to form solution C. Arrange the treated carbon in solution C and react at room temperature. After the reaction is complete, wash and dry to obtain ZIF / CC precursor. S2. Selenium source and nitrogen source are added to water in sequence to form solution D. Solution D and ZIF / CC precursor are mixed and placed in DBD microplasma reactor for DBD microplasma reaction. After the reaction is completed, the solution is washed and dried to obtain ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode.

2. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S1, the mass-to-volume ratio of the soluble cobalt salt to water is 1.164 g: 80 mL, and the soluble cobalt salt is Co(NO3)2·6H2O; the mass-to-volume ratio of the 2-methylimidazole to water is 2.627 g: 40 mL.

3. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S1, the volume ratio of solution A to solution B is 2:

1.

4. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S1, the carbon cloth is treated by immersing it in 8 mol / L nitric acid at 90°C for 1 hour, then washing it with ethanol and water in sequence, and finally drying it at 60°C for 6 hours.

5. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S1, the ratio of the amount of carbon cloth to solution C is 1 × 3 cm⁻¹. 2 120 mL, reaction time 12 h.

6. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S2, the mass-volume ratio of the selenium source, nitrogen source, and water is 20 mg: 0.5 mL: 5 mL; the selenium source is selenium powder, selenium dioxide, or sodium selenite, and the nitrogen source is hydrazine hydrate, ethylenediamine, urea, or ammonia.

7. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S2, the ratio of the ZIF / CC precursor to solution D is 1×3cm. 2 5mL.

8. The method for preparing the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 1, characterized in that, In S2, the voltage of the DBD microplasma reaction is 40-100V and the time is 50-100min.

9. A ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode prepared by the preparation method according to any one of claims 1-8.

10. The application of the ZIF-derived CoSe@nitrogen-doped polymer carbon dot self-supporting electrode according to claim 9 in dopamine electrochemical sensing and detection.

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