Preparation method and application of a MXene-based nickel-cobalt bimetallic oxide electrode material

Abstract

The present invention discloses a method for preparing a MXene-based nickel-cobalt bimetallic oxide electrode material. The method comprises the following steps: using deionized water as a solvent to prepare a mixed solution containing nickel nitrate, cobalt nitrate, urea, and MXene; pouring the mixed solution into a polytetrafluoroethylene mold and heating it in an autoclave at high temperature; after the high-pressure reaction, centrifuging the mixed solution in a centrifuge; drying the solid precipitate obtained by centrifugation in an oven; and insulating the solid precipitate in a tube furnace after drying to obtain the MXene-based nickel-cobalt bimetallic oxide electrode material. The material prepared by this method has a microstructure composed of numerous spherical crystals stacked together, has a large specific surface area, exhibits good electron transfer efficiency, and has more active sites. Compared with other electrode materials, it has higher conductivity, high surface activity, larger interlayer spacing, and good hydrophilicity.

Description

Technical Field

[0001] The present invention belongs to the field of material technology and relates to chemical sensor electrodes, in particular to a preparation method and application of a MXene-based nickel-cobalt bimetallic oxide electrode material. Background Art

[0002] Diabetes is a serious metabolic disease characterized by high blood sugar levels. Sustained high blood sugar levels and long-term metabolic disturbances can lead to damage to organs and tissues such as the heart, brain, microvasculature, kidneys, eyes, and nerves. Therefore, strict control of blood sugar concentration is crucial for the health of diabetic patients. Currently, the most widely used blood glucose monitors utilize electrochemical and photochemical methods based on glucose oxidase (GOx). Electrochemical methods offer advantages such as high sensitivity, good selectivity, excellent stability, and simple operation. However, enzyme-based glucose sensors have limitations such as high cost, inaccurate detection, and unstable performance. Therefore, the development of novel, enzyme-free electrochemical glucose sensors has become a new research hotspot.

[0003] Electrochemical sensors primarily determine glucose concentration through the reaction between electrode materials and glucose. The key is to create specialized electrode materials. Nickel, as an easily prepared metal, has excellent conductivity. Nickel foam, with its high conductivity, large specific surface area, and three-dimensional network structure, can serve as a glucose sensor. However, nickel foam itself suffers from low sensitivity and inaccurate detection. MXene, as a supercapacitor electrode material, not only enhances conductivity but also provides active sites that facilitate the reaction between substrate and glucose, thereby increasing the substrate's sensitivity to glucose. The resulting MXene-based cobalt-nickel bimetallic oxide electrode material exhibits extremely high sensitivity and detection accuracy for glucose, fully leveraging the advantages of electrochemical sensors. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the prior art and provide a method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] A method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene, the method comprising the following steps:

[0007] Step 1: Using deionized water as a solvent, a mixed solution containing nickel nitrate, cobalt nitrate, urea, and MXene is prepared;

[0008] Step 2: Pour the mixed solution into a polytetrafluoroethylene mold and place it in a high-pressure reactor for high-temperature heating;

[0009] Step 3: After the high pressure reaction is completed, the mixed solution is placed in a centrifuge for centrifugation;

[0010] Step 4: After the solution is centrifuged, the solid precipitate obtained by centrifugation is dried in an oven;

[0011] Step 5: After the solid precipitate is dried, it is placed in a tube furnace for insulation to obtain a MXene-based nickel-cobalt bimetallic oxide electrode material.

[0012] Furthermore, in step 1, the concentration of nickel nitrate in the solution is 1 to 3 mM, the concentration of cobalt nitrate in the solution is 1 to 3 mM, the concentration of urea in the solution is 1 to 3 mM, and the mass of MXene in each mixed solution with a total volume not exceeding 20 ml is 80 to 120 mg.

[0013] Furthermore, in step 2, the temperature of the high-pressure reactor is 80-120° C., and the reaction time is 8-10 h.

[0014] Furthermore, in step 3, the rotation speed during centrifugation is 3000-5000 r / min, and the centrifugation time is 8-15 min.

[0015] Furthermore, in step 4, the temperature of the oven is controlled to be 80-100° C. during drying, and the drying time is 24-36 hours.

[0016] Furthermore, in step 5, the temperature of the tube furnace is 200-300° C., and the holding time is 2-4 hours.

[0017] Application of the electrode material prepared by the preparation method described above in the preparation method of a glucose sensor.

[0018] The beneficial effects achieved by the present invention are:

[0019] 1. The MXene used in the method of the present invention is green and environmentally friendly, harmless to the human body, and has excellent electrical conductivity, hydrophilicity, adjustable interlayer spacing and surface functional groups. It can enhance the conductivity, electron transmission efficiency and ion diffusion rate of nickel-cobalt bimetallic oxide and provide active sites for it.

[0020] 2. The nickel-cobalt bimetallic oxide obtained by the method of the present invention has high specific capacitance, good conductivity, and good stability. It can be coated on the surface of MXene as a reaction substrate to protect MXene from oxidation.

[0021] 3. The one-step hydrothermal process of the present invention is relatively simple, has low energy consumption, is widely applicable, and the reaction environment is relatively closed, effectively avoiding problems such as impurities.

[0022] 4. The MXene-based nickel-cobalt bimetallic oxide developed in this invention exhibits rapid response, high sensitivity, and excellent selectivity for glucose, making it suitable for use as an electrode in a glucose sensor. This method retains the excellent rate performance of MXene while also exhibiting the unique synergistic effect of MXene and nickel-cobalt bimetallic oxide.

[0023] 5. The present method uses nickel nitrate, cobalt nitrate, urea, and MXene as raw materials. A one-step hydrothermal high-pressure reaction is carried out, followed by high-temperature heating in air in a tubular furnace. This produces a MXene-based nickel-cobalt bimetallic oxide electrode material. This material's microstructure, composed of numerous spherical crystals stacked together, offers a large specific surface area, good electron transfer, and numerous active sites. Compared to other electrode materials, it exhibits higher conductivity, high surface activity, a larger interlayer spacing, and excellent hydrophilicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Comparative SEM morphology of electrode materials prepared by the preparation method of nickel-cobalt bimetallic oxide electrode material based on MXene provided in Example 1 of the present invention and the comparative example;

[0025] Figure 2 Comparison of cyclic voltammetry (CV) results of the electrode materials prepared by the preparation methods of MXene-based nickel-cobalt bimetallic oxide electrode materials provided in Examples 1 and 2 of the present invention in 1 mM glucose solution;

[0026] Figure 3 A comparison chart of cyclic voltammetry (CV) tests of electrode materials prepared by the method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene provided in Example 1 of the present invention and the comparative example in 1 mM glucose solution;

[0027] Figure 4 Comparison chart of cyclic voltammetry (CV) tests of the electrode material prepared by the preparation method of a MXene-based nickel-cobalt bimetallic oxide electrode material provided in Example 1 of the present invention in 0.1M NaOH and 1mM glucose + 0.1M NaOH.

[0028] Figure 5 This is a comparison chart of the alternating current impedance test (EIS) of the electrode materials prepared by the preparation method of a MXene-based nickel-cobalt bimetallic oxide electrode material provided in Example 1 and Example 2 of the present invention. DETAILED DESCRIPTION

[0029] For a better understanding of the present invention, the present invention is further described in detail below with reference to the embodiments. However, the scope of protection claimed by the present invention is not limited to the scope represented by the embodiments.

[0030] Unless otherwise specified, the raw materials used in the present invention are all conventional commercial products. Unless otherwise specified, the methods used in the present invention are all conventional methods in the art. The quality of each substance used in the present invention is the quality of conventional use.

[0031] A method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene, the method comprising the following steps:

[0032] Step 1: Using deionized water as a solvent, a mixed solution containing nickel nitrate, cobalt nitrate, urea, and MXene is prepared;

[0033] Step 2: Pour the mixed solution into a polytetrafluoroethylene mold and place it in a high-pressure reactor for high-temperature heating;

[0034] Step 3: After the high pressure reaction is completed, the mixed solution is placed in a centrifuge for centrifugation;

[0035] Step 4: After the solution is centrifuged, the solid precipitate obtained by centrifugation is dried in an oven;

[0036] Step 5: After the solid precipitate is dried, it is placed in a tube furnace for insulation to obtain a MXene-based nickel-cobalt bimetallic oxide electrode material.

[0037] Preferably, in step 1, the concentration of nickel nitrate in the solution is 1-3 mM, the concentration of cobalt nitrate in the solution is 1-3 mM, the concentration of urea in the solution is 1-3 mM, and the mass of MXene in each mixed solution with a total volume not exceeding 20 ml is 80-120 mg.

[0038] Preferably, in step 2, the temperature of the autoclave is 80-120° C., and the reaction time is 8-10 h.

[0039] Preferably, in step 3, the rotation speed during centrifugation is 3000-5000 r / min, and the centrifugation time is 8-15 min.

[0040] Preferably, in step 4, the temperature of the oven is controlled at 80-100° C. during drying, and the drying time is 24-36 hours.

[0041] Preferably, in step 5, the temperature of the tube furnace is 200-300° C., and the holding time is 2-4 hours.

[0042] Application of the electrode material prepared by the preparation method described above in the preparation method of a glucose sensor.

[0043] Specifically, the relevant preparation and testing are as follows:

[0044] Example 1

[0045] A method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene, the specific operation method is as follows:

[0046] Step 1: Using deionized water as the solvent, prepare a mixed solution containing 3 mM nickel nitrate, 1 mM cobalt nitrate, 1 mM urea, and 100 mg MXene. The total volume of the mixed solution does not exceed 20 ml.

[0047] Step 2: Pour the mixed solution into a polytetrafluoroethylene mold and place it into a high-pressure reactor and heat it at 120° C. for 10 hours.

[0048] Step 3: After the high pressure reaction is completed, the mixed solution is placed in a centrifuge at a speed of 5000 r / min and centrifuged for 10 minutes.

[0049] Step 4: After the solution is centrifuged, the solid precipitate obtained by centrifugation is dried in an oven at 100° C. for 24 h.

[0050] Step 5: After the solid precipitate is dried, it is placed in a tube furnace at 300°C and kept warm for 2 hours.

[0051] A nickel-cobalt bimetallic oxide electrode material based on MXene was prepared.

[0052] Example 2

[0053] A method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene, the specific operation method is as follows:

[0054] Step 1: Using deionized water as the solvent, prepare a mixed solution containing 1 mM nickel nitrate, 3 mM cobalt nitrate, 1 mM urea, and 100 mg MXene. The total volume of the mixed solution does not exceed 20 ml.

[0055] Step 2: Pour the mixed solution into a polytetrafluoroethylene mold and place it into a high-pressure reactor and heat it at 120° C. for 10 hours.

[0056] Step 3: After the high pressure reaction is completed, the mixed solution is placed in a centrifuge at a speed of 5000 r / min and centrifuged for 10 minutes.

[0057] Step 4: After the solution is centrifuged, the solid precipitate obtained by centrifugation is dried in an oven at 80° C. for 24 h.

[0058] Step 5: After the solid precipitate is dried, it is placed in a tube furnace at 300°C and kept warm for 4 hours.

[0059] A nickel-cobalt bimetallic oxide electrode material based on MXene was prepared.

[0060] Comparative Example

[0061] A method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene, the specific operation method is as follows:

[0062] Step 1: Using deionized water as solvent, prepare a mixed solution containing 3 mM nickel nitrate, 1 mM cobalt nitrate and 1 mM urea, with the total volume of the mixed solution not exceeding 20 ml.

[0063] Step 2: Pour the mixed solution into a polytetrafluoroethylene mold and place it into a high-pressure reactor and heat it at 120° C. for 10 hours.

[0064] Step 3: After the high pressure reaction is completed, the mixed solution is placed in a centrifuge at a speed of 5000 r / min and centrifuged for 10 minutes.

[0065] Step 4: After the solution is centrifuged, the solid precipitate obtained by centrifugation is dried in an oven at 100° C. for 24 h.

[0066] Step 5: After the solid precipitate is dried, it is placed in a tube furnace at 300°C and kept warm for 2 hours.

[0067] A nickel-cobalt bimetallic oxide electrode material based on MXene was prepared.

[0068] Figure 1 This is a SEM morphology comparison diagram of Example 1 and the comparative example. By comparison, Example 1 has many spherical crystals piled together, with a large specific surface area. When reacting with glucose, it can have a better electron transfer effect and more active sites. Figure 2 This is a comparison chart of cyclic voltammetry (CV) tests of Example 1 and Example 2. It can be seen from the figure that when Ni:Co is set to 3:1 during the preparation of the electrode material, its peak shape is more obvious, proving that its conductivity is better than that when Ni:Co is set to 1:3. Figure 3 This is a comparison chart of cyclic voltammetry (CV) tests of Example 1 and the comparative example. It can be seen from the figure that when Ni:Co is set to 3:1 during the preparation of the electrode material, the peak type of the composite material after adding Mxene is more obvious, proving that its conductivity is improved. It can be proved that Mxene has a synergistic effect with nickel nitrate and cobalt nitrate, and can synergistically improve the relevant properties of the obtained electrode material. Figure 4 This is a comparison chart of the cyclic voltammetry test (CV) of Example 1 in 0.1MNaOH and 1mM glucose + 0.1MNaOH. It can be seen that in the presence of glucose, the peak shape of the material is more obvious, proving that its conductivity is improved, which proves the excellent specificity of the material for glucose. Figure 5The EIS test (EIS) comparison diagram of Example 1 and Example 2 shows that during the preparation of the electrode material, the diameter of the capacitive arc with Ni:Co=3:1 is smaller than the x-axis intercept, so its Rct (charge transfer resistance) and R Ω Smaller, proving that the material has better charge transport performance.

[0069] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing a nickel-cobalt bimetallic oxide electrode material based on MXene, characterized in that: The specific operation method is: Step 1: Using deionized water as the solvent, prepare a mixed solution containing 3 mM nickel nitrate, 1 mM cobalt nitrate, 1 mM urea, and 100 mg MXene. The total volume of the mixed solution does not exceed 20 ml. Step 2: Pour the mixed solution into a polytetrafluoroethylene mold and heat it in a high-pressure reactor at 120°C for 10 hours; Step 3: After the high pressure reaction is completed, the mixed solution is placed in a centrifuge at a speed of 5000 r / min and centrifuged for 10 minutes; Step 4: After the solution is centrifuged, the solid precipitate obtained by centrifugation is dried in an oven at 100° C. for 24 h; Step 5: After the solid precipitate is dried, it is placed in a tube furnace at 300°C and kept warm for 2 hours; Prepared MXene-based nickel-cobalt bimetallic oxide electrode materials; The sensitivity of the electrode material in the non-enzymatic glucose sensor is ≥7 mA·mM-1·cm -2 , detection limit ≤5μM.

2. Use of the electrode material prepared by the preparation method according to claim 1 in a method for preparing a glucose sensor.

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