Hydrogen peroxide electrochemical sensing electrode, preparation method and application thereof

Abstract

This invention relates to a hydrogen peroxide electrochemical sensor electrode, its preparation method, and its application. The invention first prepares a monolayer of MXene, and then uses it to prepare an MXene / Co mixture via a hydrothermal method with cobalt acetate tetrahydrate. 3 O 4 The nanocomposite material was then used to modify a glassy carbon electrode. This invention utilizes MXene and Co... 3 O 4 The composite material not only possesses excellent catalytic ability for hydrogen peroxide, but the presence of MXene also enhances its electron transfer-promoting ability, thereby improving catalytic efficiency. This composite material exhibits excellent hydrogen peroxide detection capabilities, with a good linear relationship between the obtained hydrogen peroxide concentration and current value, enabling quantitative detection of hydrogen peroxide content. The process of this invention is simple, stable, and low-cost; the detection limit for hydrogen peroxide reaches 0.196 μmol / L, demonstrating good detection performance and anti-interference ability.

Description

A hydrogen peroxide electrochemical sensing electrode, its preparation method and application Technical Field

[0001] This invention belongs to the technical field of peroxide detection, specifically relating to an electrochemical sensor electrode for hydrogen peroxide, its preparation method, and its application. Background Technology

[0002] Hydrogen peroxide, a common and important small molecule, is a crucial indicator substance within biological cells, playing a role in signal transduction and closely related to human physiological processes, the aging process, and many diseases. Furthermore, hydrogen peroxide is widely present and plays a role in the food and environmental fields. Currently, methods for detecting hydrogen peroxide mainly include titration, chemiluminescence, chromatography, fluorescence, and electrochemical methods. Among these, electrochemical methods offer advantages such as high sensitivity, low cost, ease of operation, faster response time, and portability compared to other methods. Although enzyme-based electrochemical biosensors have been favored in previous studies due to their high sensitivity and selectivity, their complex structure, high manufacturing cost, and stringent environmental requirements limit their practical application. Therefore, the use of non-enzyme electrochemical sensors, including carbon-based materials, metal oxide materials, and hydroxide materials, for hydrogen peroxide detection has been rapidly developed due to their simplicity, low cost, fast response speed, and high sensitivity. However, existing methods also suffer from drawbacks such as poor selectivity and limited electronic conductivity. To address these issues, developing high-performance electrode materials for hydrogen peroxide electrochemical sensors is crucial.

[0003] Existing technology CN 112986358 A describes a method for determining hydrogen peroxide using an electrochemical biosensor based on Ti3C2. The method includes steps (a) constructing a biocomposite material HRP@Ti3C2 / Nafion: using PBS buffer solution with a pH of 7–7.4 as the reaction solvent, Ti3C2 nanomaterials are co-incubated with HRP and Nafion to construct the biocomposite material HRP@Ti3C2 / Nafion; and step (b) electrode modification: the biocomposite material HRP@Ti3C2 / Nafion constructed in step (a) is drop-coated onto the surface of a glassy carbon electrode to obtain a modified glassy carbon electrode. The modified glassy carbon electrode prepared by this method can be used to determine hydrogen peroxide, but its cost is relatively high. Summary of the Invention

[0004] To overcome the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing an electrochemical sensor electrode for hydrogen peroxide with excellent catalytic function. This invention constructs a highly efficient hydrogen peroxide sensor coating on the surface of a glassy carbon electrode using a hydrothermal reaction and drop-coating method. This coating possesses a two-dimensional nanostructure with a large number of cobalt tetroxide nanoparticles bonded to an MXene surface. This electrode coating exhibits high detection sensitivity, achieving highly sensitive detection of hydrogen peroxide.

[0005] Another object of the present invention is to provide a hydrogen peroxide electrochemical sensor electrode prepared by the above method.

[0006] Another object of the present invention is to provide an application of the above-described hydrogen peroxide electrochemical sensor electrode. The hydrogen peroxide electrochemical sensor electrode is used for the efficient detection of hydrogen peroxide.

[0007] The present invention achieves its objective through the following technical solutions:

[0008] A method for preparing an electrochemical sensor electrode for hydrogen peroxide includes the following steps:

[0009] (1) Prepare monolayer MXene by ultrasonically dispersing monolayer MXene in ethanol to obtain MXene ethanol dispersion for later use;

[0010] (2) Preparation of MXene / Co3O4 nanocomposite materials

[0011] A mixture of water and ethanol of cobalt acetate tetrahydrate was stirred and mixed with MXene ethanol dispersion, and ammonia was added. The mixture was then heated to react. After the reaction was completed, the precipitate was separated by centrifugation, washed and dried to obtain MXene / Co3O4 nanocomposite material.

[0012] (3) Preparation of composite material modified electrodes

[0013] The MXene / Co3O4 nanocomposite material was ultrasonically dispersed in a mixed solution of deionized water, Nafion solution and isopropanol solution. The ultrasonically dispersed solution was then drop-coated onto the surface of a polished glassy carbon electrode and allowed to evaporate and dry naturally in the air to obtain the MXene / Co3O4 nanocomposite material modified electrode, which is the hydrogen peroxide electrochemical sensor electrode.

[0014] Preferably, the specific steps of step (1) are as follows: under stirring conditions, MAX material (Ti3AlC2) is added to the solvent for etching reaction, so that the Al layer is separated from the MAX phase. After the etching reaction is completed, the material is centrifuged and filtered, the precipitate is collected and washed to obtain multilayer Ti3C2T x Precipitation; using LiCl solution to precipitate multilayer Ti3C2T xThe precipitate was washed into another reaction vessel for intercalation. After the reaction, the mixture was centrifuged and washed until the supernatant turned a clear dark green. Centrifugation was then stopped, and the supernatant was the monolayer Ti3C2T. x MXene dispersion; the resulting monolayer Ti3C2T x The MXene dispersion was dried to obtain a monolayer of MXene; the monolayer of MXene was ultrasonically dispersed in ethanol to obtain an MXene ethanol dispersion for later use.

[0015] More preferably, the solvent is prepared from HCl solution, HF solution and deionized water; the volume ratio of HCl solution, HF solution and deionized water is (6-12):(1-2):(3-6), preferably 36:6:18; the concentration of HCl solution is 10.8 mol / L and the concentration of HF solution is 22.5 mol / L.

[0016] More preferably, the etching reaction temperature is 30–60°C, and more preferably 45°C.

[0017] More preferably, the etching reaction takes 24 to 48 hours, preferably 36 hours.

[0018] More preferably, the mass ratio of the MAX material to the LiCl in the LiCl solution is 1-2:1-2, preferably 1:1.

[0019] More preferably, the centrifugation speed is 3000-5000 rpm, preferably 3500 rpm; the centrifugation time is 3-7 min, preferably 5 min.

[0020] More preferably, the temperature of the intercalation reaction is 30-60°C, preferably 45°C; and the time of the intercalation reaction is 16-32 hours, preferably 24 hours.

[0021] More preferably, the drying temperature is ≤60°C.

[0022] Preferably, the mass ratio of cobalt acetate tetrahydrate to monolayer MXene in step (2) is 2.0-3.0:0.008-0.036, more preferably 2.5:0.01-0.05, and most preferably 2.5:0.02.

[0023] The ammonia concentration mentioned in step (2) is 37% (mass concentration).

[0024] The heating reaction in step (2) is carried out at a temperature of 120 to 180°C, preferably 150°C.

[0025] The heating reaction time in step (2) is 2 to 4 hours, preferably 3 hours.

[0026] The drying temperature mentioned in step (2) is ≤80℃.

[0027] The ratio of MXene / Co3O4 nanocomposite material, deionized water, Nafion solution and isopropanol solution used in step (3) is 2.0-4.0 mg: 0.25-0.50 mL: 0.50-0.65 mL, preferably 3.0 mg: 0.375 mL: 0.050 mL: 0.575 mL.

[0028] The Nafion solution concentration mentioned in step (3) is 5 wt%.

[0029] The ultrasonic dispersion time in step (3) is 10 to 20 minutes, preferably 15 minutes.

[0030] The hydrogen peroxide electrochemical sensor electrode described in this invention is used for hydrogen peroxide concentration detection.

[0031] The steps for applying the hydrogen peroxide electrochemical sensor electrode to detect hydrogen peroxide include: using a platinum sheet as the counter electrode, Ag / AgCl as the reference electrode, the hydrogen peroxide electrochemical sensor electrode as the working electrode, using a KCl solution of a certain concentration as the electrolyte, adding H2O2 solution to the KCl solution, detecting the current value by a constant potential instantaneous current test method at a certain potential, and quantitatively detecting the concentration of H2O2 by utilizing the linear relationship between the H2O2 concentration and the current value.

[0032] The linear relationship between H2O2 concentration and current value is as follows: I = -0.0216C - 12.4526, where I represents the current value in μA and C represents the H2O2 concentration in μmol / L.

[0033] The current-concentration relationship between H2O2 concentration and concentration is very good in the range of 0-1.0 mmol / L.

[0034] The concentration of the KCl solution is 0.1 mol / L to 0.5 mol / L, preferably 0.1 mol / L.

[0035] The potential is -0.3 to -0.4V, preferably -0.35V.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] (1) This invention utilizes hydrothermal treatment technology to construct a hydrogen peroxide electrochemical sensor electrode modified with a catalytically active semiconductor two-dimensional nanomaterial, MXene / Co3O4 composite. Cobalt tetroxide, as a metal oxide semiconductor, possesses excellent catalytic properties and can promote the redox reaction of hydrogen peroxide. Simultaneously, the presence of MXene effectively enhances the adsorption of hydrogen peroxide and promotes electron transfer, providing a more convenient transport pathway for reaction intermediates and further accelerating the hydrogen peroxide reaction process.

[0038] (2) The preparation process of this invention is simple, stable and low cost. The prepared Co3O4 nanoparticles are generated on the surface of MXene. While ensuring that the material can catalyze hydrogen peroxide, it can also promote the transfer of electrons, thereby promoting the faster occurrence of the reduction reaction.

[0039] (3) The electrode material of the present invention has low interface resistance and has a low detection limit and a wide detection range for the detection of hydrogen peroxide, and has a wide range of applications. Attached Figure Description

[0040] Figure 1 is a scanning electron image of the monolayer MXene prepared in Example 1;

[0041] Figure 2 is a scanning electron image of the MXene / Co3O4 nanocomposite material prepared in Example 1;

[0042] Figure 3 shows the X-ray photoelectron spectroscopy full spectrum analysis of the MXene / Co3O4 nanocomposite material prepared in Example 1; (b) shows the high-resolution Ti2p spectrum analysis of the MXene / Co3O4 nanocomposite material; and (c) shows the high-resolution Co2p spectrum analysis of the MXene / Co3O4 nanocomposite material.

[0043] Figure 4 shows the CV curves of the composite material modified electrodes in Examples 1, 2, and 3, respectively, tested in a solution containing 6 mM H2O2. MXene / Co3O4-1 represents the composite material modified electrode prepared in Example 2, MXene / Co3O4-2 represents the composite material modified electrode prepared in Example 1, and MXene / Co3O4-3 represents the composite material modified electrode prepared in Example 3.

[0044] Figure 5(a) shows the Ampere response of the hydrogen peroxide electrochemical sensor electrode in Example 4 (the inset shows the time to reach steady state after adding hydrogen peroxide); (b) shows the linear fitting curve of hydrogen peroxide concentration and current intensity in Example 4.

[0045] Figure 6 shows the amperometric response on the hydrogen peroxide electrochemical sensor electrode in Example 4 after hydrogen peroxide, glucose, uric acid, urea, sodium chloride, and hydrogen peroxide were added sequentially to a 0.1 mol / L KCl solution. Detailed Implementation

[0046] The specific embodiments of the present invention will be further described in detail below with reference to specific examples. Many specific details are set forth in the following description to provide a thorough understanding of the present invention, but the embodiments of the present invention are not limited thereto. Examples 1-3 illustrate the specific preparation of the MXene / Co3O4 nanocomposite material and the preparation of the modified electrode; Example 4 illustrates the detection of hydrogen peroxide by an electrochemical sensor electrode for hydrogen peroxide.

[0047] Example 1

[0048] (1) Preparation of MXene: Add 36.0 mL of 10.8 mol / L HCl, 18 mL of deionized water, and 6 mL of 22.5 mol / L HF solution to a 50 mL PTFE etching cup. Place the cup in a water bath and stir. Set the water bath temperature to 45℃. Weigh 3.0 g of Ti3AlC2 material and slowly add it to the PTFE etching cup. Cover the cup and allow it to react for 36 h. After the reaction is complete, transfer the solution to a centrifuge tube and centrifuge at 3500 rpm for 5 min. Pour off the acid solution, add deionized water, and continue centrifuging at 3500 rpm for 5 min until the pH of the solution is approximately 6. Stop washing to obtain multilayer Ti3C2T x Precipitation. Weigh 3.0 g of LiCl powder and dissolve it in 50 mL of deionized water. Use this solution to precipitate the resulting multilayer Ti3C2T. x The precipitate was washed into a new etching cup and heated in a water bath at 45°C for 24 hours. After the reaction was complete, the solution was centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded, and the solution was washed with deionized water until the supernatant turned dark green. The supernatant is the monolayer MXene dispersion, and the bottom layer consists of the remaining multilayer Ti3C2T. x And incompletely etched Ti3AlC2. The resulting monolayer MXene dispersion was placed in a vacuum drying oven and dried at 50°C to obtain monolayer MXene material.

[0049] (2) Preparation of MXene / Co3O4 nanocomposite material: Prepare a 100 mL mixed solution of water and ethanol (water:ethanol = 1:9, v / v), weigh 2.5 g of cobalt acetate tetrahydrate powder into the solution and ultrasonically mix it evenly (10-15 min) to obtain a pink transparent cobalt acetate solution. Weigh 20 mg of monolayer MXene and disperse it in 10 mL of ethanol, and ultrasonically mix it in an ice bath for 10 min; stir and mix the ultrasonically obtained MXene ethanol dispersion with the cobalt acetate solution and add 25 mL of 37% ammonia water; transfer the solution to a polytetrafluoroethylene reactor and react at 150 °C for 3 hours. After the reactor cools, centrifuge the obtained solution to separate the precipitate, and wash the precipitate with water and ethanol until the supernatant is transparent and odorless. Place the washed precipitate in a drying oven at 60 °C for 12 hours to obtain the MXene / Co3O4 nanocomposite material.

[0050] (3) Preparation of composite material modified electrode: A 3 mm glassy carbon electrode was polished using alumina powder, then ultrasonically treated in ethanol and deionized water respectively, and air-dried for later use. 3.0 mg of MXene / Co3O4 nanocomposite material was weighed and dispersed in a mixed solution containing 0.375 mL of deionized water, 50 μL of 5 wt% Nafion solution, and 0.575 mL of isopropanol solution, and ultrasonically dispersed for 15 min. 2.5 μL of the ultrasonically dispersed solution was dropped onto the surface of the glassy carbon electrode and allowed to evaporate naturally in air to obtain the MXene / Co3O4 nanocomposite material modified electrode.

[0051] Figure 1 shows the SEM image of the monolayer MXene prepared in Example 1. Figure 2 shows the SEM image of the MXene / Co3O4 nanocomposite material prepared in Example 1; as shown in Figure 2, the prepared Co3O4 nanoparticles are distributed on the surface of the monolayer MXene. Figure 3 shows the X-ray photoelectron spectrum of the MXene / Co3O4 nanocomposite material prepared in Example 1. In addition to the characteristic peaks of C and O elements, there are also obvious characteristic peaks of Co and Ti elements. Fitting analysis of the high-magnification scanning spectra of Ti and Co elements on the material surface revealed that Ti2p splits into Ti2p. 3 / 2 and Ti2p 1 / 2 Two spin orbital bimodalities were observed, with high-intensity peaks concentrated at 458.4 eV and 463.6 eV, which are characteristic peak positions of Ti-C, and low-intensity peaks concentrated at 459.4 eV and 465.1 eV, which are characteristic peak positions of Ti-O. Simultaneously, Co2p spin orbital splitting was observed at 780.0 eV and 795.2 eV, corresponding to the Co2p3 / 2 and Cop1 / 2 regions respectively, with a spin energy difference of 15.2 eV. All these analyses indicate the successful preparation of the MXene / Co3O4 nanocomposite material.

[0052] Example 2

[0053] (1) Preparation of MXene: Add 36.0 mL of 10.8 mol / L HCl, 18 mL of deionized water, and 6 mL of 22.5 mol / L HF solution to a 50 mL PTFE etching cup. Place the cup in a water bath and stir. Set the water bath temperature to 45℃. Weigh 3.0 g of Ti3AlC2 material and slowly add it to the PTFE etching cup. Cover the cup and allow it to react for 36 h. After the reaction is complete, transfer the solution to a centrifuge tube and centrifuge at 3500 rpm for 5 min. Pour off the acid solution, add deionized water, and continue centrifuging at 3500 rpm for 5 min until the pH of the solution is approximately 6. Stop washing to obtain multilayer Ti3C2T x Precipitation. Weigh 3.0 g of LiCl powder and dissolve it in 50 mL of deionized water. Use this solution to precipitate the resulting multilayer Ti3C2T. x The precipitate was washed into a new etching cup and heated in a water bath at 45°C for 24 hours. After the reaction was complete, the solution was centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded, and the solution was washed with deionized water until the supernatant turned dark green. The supernatant was the monolayer MXene dispersion, with multiple layers of Ti3C2T remaining at the bottom. x And incompletely etched Ti3AlC2. The resulting monolayer MXene dispersion was placed in a vacuum drying oven and dried at 50°C to obtain monolayer MXene material.

[0054] (2) Preparation of MXene / Co3O4 composite material: Prepare a 100 mL mixed solution of water and ethanol (water:ethanol = 1:9, v / v), weigh 2.5 g of cobalt acetate tetrahydrate powder into the solution and ultrasonically mix it evenly (10-15 min) to obtain a pink transparent cobalt acetate solution. Weigh 10 mg of monolayer MXene and disperse it in 10 mL of ethanol, and ultrasonically mix it in an ice bath for 10 min; stir and mix the ultrasonically obtained MXene ethanol dispersion with the cobalt acetate solution and add 25 mL of 37% ammonia water; transfer the solution to a polytetrafluoroethylene reactor and react at 150 °C for 3 hours. After the reactor cools, centrifuge the obtained solution to separate the precipitate, and wash the precipitate with water and ethanol until the supernatant is transparent and odorless. Place the washed precipitate in a drying oven at 60 °C for 12 hours to obtain the MXene / Co3O4 nanocomposite material.

[0055] (3) Preparation of composite material modified electrode: A 3 mm glassy carbon electrode was polished using alumina powder, then ultrasonically treated in ethanol and deionized water respectively, and air-dried. 3.0 mg of MXene / Co3O4 nanocomposite material was weighed and dispersed in a mixed solution containing 0.375 mL of deionized water, 50 μL of 5 wt% Nafion solution, and 0.575 mL of isopropanol solution, and ultrasonically dispersed for 15 min. 2.5 μL of the ultrasonically dispersed solution was dropped onto the surface of the glassy carbon electrode and allowed to evaporate naturally in air to obtain the MXene / Co3O4 nanocomposite material modified electrode.

[0056] The composite material prepared in this embodiment has a similar structure and testing performance to that in Example 1, as shown in Figure 4.

[0057] Example 3

[0058] (1) Preparation of MXene: Add 36.0 mL of 10.8 mol / L HCl, 18 mL of deionized water, and 6 mL of 22.5 mol / L HF solution to a 50 mL PTFE etching cup. Place the cup in a water bath and stir. Set the water bath temperature to 45℃. Weigh 3.0 g of Ti3AlC2 material and slowly add it to the PTFE etching cup. Cover the cup and allow it to react for 36 h. After the reaction is complete, transfer the solution to a centrifuge tube and centrifuge at 3500 rpm for 5 min. Pour off the acid solution, add deionized water, and continue centrifuging at 3500 rpm for 5 min until the pH of the solution is approximately 6. Stop washing to obtain multilayer Ti3C2T x Precipitation. Weigh 3.0 g of LiCl powder and dissolve it in 50 mL of deionized water. Use this solution to precipitate the resulting multilayer Ti3C2T. x The precipitate was washed into a new etching cup and heated in a water bath at 45°C for 24 hours. After the reaction was complete, the solution was centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded, and the solution was washed with deionized water until the supernatant turned dark green. The supernatant was the monolayer MXene dispersion, with multiple layers of Ti3C2T remaining at the bottom. x And incompletely etched Ti3AlC2. The resulting monolayer MXene dispersion was placed in a vacuum drying oven and dried at 50°C to obtain monolayer MXene material.

[0059] (2) Preparation of MXene / Co3O4 composite material: Prepare a 100 mL mixed solution of water and ethanol (water:ethanol = 1:9, v / v), weigh 2.5 g of cobalt acetate tetrahydrate powder into the solution and ultrasonically mix it evenly (10-15 min) to obtain a pink transparent cobalt acetate solution. Weigh 50 mg of monolayer MXene and disperse it in 10 mL of ethanol, and ultrasonically mix it in an ice bath for 10 min; stir and mix the ultrasonically obtained MXene ethanol dispersion with the cobalt acetate solution and add 25 mL of 37% ammonia water; transfer the solution to a polytetrafluoroethylene reactor and react at 150 °C for 3 hours. After the reactor cools, centrifuge the obtained solution to separate the precipitate, and wash the precipitate with water and ethanol until the supernatant is transparent and odorless. Place the washed precipitate in a drying oven at 60 °C for 12 hours to obtain the MXene / Co3O4 nanocomposite material.

[0060] (3) Preparation of composite material modified electrode: A 3 mm glassy carbon electrode was polished using alumina powder, then ultrasonically treated in ethanol and deionized water respectively, and air-dried. 3.0 mg of MXene / Co3O4 nanocomposite material was weighed and dispersed in a mixed solution containing 0.375 mL of deionized water, 50 μL of 5 wt% Nafion solution, and 0.575 mL of isopropanol solution, and ultrasonically dispersed for 15 min. 2.5 μL of the ultrasonically dispersed solution was dropped onto the surface of the glassy carbon electrode and allowed to evaporate naturally in air to obtain the MXene / Co3O4 nanocomposite material modified electrode.

[0061] The composite material prepared in this embodiment has a similar structure and testing performance to that in Example 1, as shown in Figure 4.

[0062] Example 4 (Application Example)

[0063] The MXene / Co3O4 nanocomposite modified electrode (hydrogen peroxide electrochemical sensor electrode) prepared in Example 1 was used as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode. A 0.1 mol / L KCl solution was used as the electrolyte. A certain concentration of H2O2 solution was continuously added to the KCl solution, and the current value was detected by a potentiostatic instantaneous current measurement method at a potential of -0.35 V. The measured it curve is shown in Figure 5(a), and the relationship between the response current and the H2O2 concentration is shown in Figure 5(b). It can be seen that within the linear range of H2O2 concentration of 0-1.0 mmol / L, the H2O2 concentration and the corresponding current value show a good linear relationship, with a linear relationship of I = -0.0216C - 12.4526 and a linear correlation coefficient R. 2=0.998; where I represents the current value in μA and C represents the H2O2 concentration in μmol / L. The calculated detection limit of the hydrogen peroxide electrochemical sensor in this embodiment is 0.196 μmol / L.

[0064] The electrodes prepared in Examples 2 and 3 also have good hydrogen peroxide detection capabilities, and the detection results are highly reliable.

[0065] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an electrochemical sensor electrode for hydrogen peroxide, characterized in that, Includes the following steps: (1) Under stirring conditions, the MAX material was added to the solvent and etched at 30~60℃ for 24~48 h to separate the Al layer from the MAX phase. After the etching reaction was completed, the material was centrifuged and filtered. The precipitate was collected and washed to obtain multilayer Ti3C2T. x Precipitation; using LiCl solution to precipitate multilayer Ti3C2T x The precipitate was washed into another reaction vessel and subjected to an intercalation reaction at 30–60 °C for 16–32 h. After the reaction, the mixture was centrifuged and washed until the supernatant turned a transparent dark green. Centrifugation was then stopped, and the supernatant was the monolayer Ti3C2T. x MXene dispersion; the resulting monolayer Ti3C2T x The MXene dispersion was dried to obtain a single layer of MXene, which was then ultrasonically dispersed in ethanol to obtain an MXene ethanol dispersion for later use. The solvent was prepared by mixing HCl solution, HF solution and deionized water in a volume ratio of (6~12):(1~2):(3~6). (2) The water and ethanol mixture of cobalt acetate tetrahydrate was stirred and mixed with the MXene ethanol dispersion, and ammonia was added. The mixture was heated at 120~180℃ for 2~4 h. After the reaction was completed, the precipitate was separated by centrifugation, washed and dried to obtain the MXene / Co3O4 nanocomposite material. The mass ratio of the single layer of MXene in the cobalt acetate tetrahydrate and MXene ethanol dispersion was 2.0~3.

0. : 0.008~0.036; (3) Take MXene / Co3O4 nanocomposite material and ultrasonically disperse it in a mixed solution of deionized water, Nafion solution and isopropanol solution. Take the ultrasonically dispersed solution and drop it onto the surface of the polished glassy carbon electrode. Let it evaporate and dry naturally in the air to obtain the MXene / Co3O4 nanocomposite material modified electrode, which is the hydrogen peroxide electrochemical sensor electrode.

2. The method according to claim 1, characterized in that, The volume ratio of the HCl solution, HF solution, and deionized water is 36:6:18; the concentration of the HCl solution is 10.8 mol / L, and the concentration of the HF solution is 22.5 mol / L; the mass ratio of the MAX material to the LiCl in the LiCl solution is 1~2:1~2; the etching reaction temperature is 45℃; the etching reaction time is 36 h; the intercalation reaction temperature is 45℃; and the intercalation reaction time is 24 h.

3. The method according to claim 2, characterized in that, The mass ratio of the MAX material to the LiCl in the LiCl solution is 1:

1.

4. The method according to claim 1, characterized in that, The mass ratio of cobalt acetate tetrahydrate to monolayer MXene in step (2) is 2.5:0.02; the mass concentration of ammonia in step (2) is 37%.

5. The method according to claim 1, characterized in that, The heating reaction in step (2) is carried out at a temperature of 150°C and for a duration of 3 hours.

6. The method according to claim 1, characterized in that, The ratio of MXene / Co3O4 nanocomposite material, deionized water, Nafion solution and isopropanol solution used in step (3) is 3.0 mg: 0.375 mL: 0.050 mL: 0.575 mL; the concentration of Nafion solution used in step (3) is 5 wt%.

7. The method according to claim 1, characterized in that, The drying temperature in step (2) is ≤80℃; the ultrasonic dispersion time in step (3) is 10~20 min.

8. The method according to claim 7, characterized in that, The ultrasonic dispersion time mentioned in step (3) is 15 min.

9. A hydrogen peroxide electrochemical sensor electrode prepared by the method according to any one of claims 1 to 8.

10. The application of the hydrogen peroxide electrochemical sensor electrode according to claim 9 in the detection of hydrogen peroxide concentration.

11. The application according to claim 10, characterized in that, The process includes the following steps: using a platinum sheet as the counter electrode, Ag / AgCl as the reference electrode, and the hydrogen peroxide electrochemical sensor electrode as the working electrode; using KCl solution as the electrolyte; adding H2O2 solution to the KCl solution; detecting the current value at a certain potential using a constant potential instantaneous current testing method; and quantitatively detecting the concentration of H2O2 by utilizing the linear relationship between the H2O2 concentration and the current value.

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