A single-atom-loaded Mxene material and its efficient preparation method and application

Abstract

The present invention belongs to the technical field of single-atom catalysts and discloses a single-atom-loaded MXene material, its efficient preparation method, and application. The method comprises the following steps: 1) dissolving a metal salt corresponding to a target metal single atom in water to obtain a metal ion solution A; 2) mixing the metal ion solution A with a MXene dispersion to obtain a suspension B; 3) placing the suspension B in a gas-liquid discharge plasma reactor and conducting a discharge reaction under an argon plasma atmosphere for 1 to 10 minutes to obtain a suspension C; solid-liquid separation and drying are performed to obtain the metal single-atom-loaded MXene material. The method of the present invention has high processing efficiency and simple operation, and can be used for the efficient preparation and large-scale production of different single-atom-loaded MXene materials. The prepared material has a high utilization rate of metal ions and a more stable coordination state of the single atoms. The material of the present invention has applications in the field of electrochemical catalysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of single-atom catalysts, and specifically relates to a plurality of single-atom-loaded Mxene two-dimensional materials prepared using liquid-phase discharge plasma technology, and a preparation method and application thereof. Background Art

[0002] Single-atom catalysts, that is, single atoms (generally highly active metal atoms) uniformly dispersed on different substrates as catalysts, have become key frontier materials in the fields of chemical or energy conversion and heterogeneous catalysis, and have received widespread attention in recent years. In addition to having the highest atomic utilization efficiency, single-atom catalysts also have the advantages of high intrinsic activity, flexible selectivity and low cost. At the same time, the synergistic effect of single metal atoms and the corresponding matrix is ​​utilized to give single-atom catalysts unique physicochemical properties that can meet various requirements. How to synthesize stable single-atom supported catalysts on suitable supports is a prerequisite for scientific research and practical application of such materials. However, the surface free energy of metals will increase significantly with the decrease in metal particle size, which will cause isolated single atoms to easily aggregate into nanoparticles during the synthesis and reaction process, thereby losing their performance advantages. At present, in order to maintain the isolated single-atom state of metal atoms on the matrix material, there are two aspects: thermodynamic stability and kinetic stability. Thermodynamic stability means forming a strong covalent bond between the central metal atom and the surrounding coordinating atoms, thereby reducing the overall chemical potential of the single-atom loaded catalyst. When the free energy of the single-atom loaded material is lower than that of its nanoparticle system, the metal nanoparticles can spontaneously disperse into single atoms; kinetic stability means that if the aggregation energy barrier of metal atoms on a certain substrate is high enough, even if the free energy of its single-atom system is higher than that of the metal nanoparticles, its agglomeration phenomenon will be suppressed, so that its single atoms can be stably loaded on the surface of the substrate.

[0003] Mxene(M n+1 X n T x MXene (n = 1, 2 or 3) is a two-dimensional transition metal carbon / nitrogen / carbonitride material, where M is a transition metal element (Ti, Ta, Nb, etc.), X is C and / or N, and T is a functional group (-O, -OH, -F, etc.). The functional groups on the surface of the MXene material can effectively adsorb positively charged metal ions and serve as anchoring points to fix single atoms. In addition, the MXene material also has the characteristics of diverse composition, adjustable structure, high conductivity (>10000S / cm), and hydrophilic interface. Therefore, MXene materials are considered to be ideal supports for single-atom catalysts and have received widespread attention in recent years.

[0004] Based on this theory, researchers have proposed an impregnation and coprecipitation method for the preparation and synthesis of single-atom-loaded MXene materials. For example, Chinese invention patent application CN201911268294.5 provides a method for preparing single-atom-loaded MXene materials: a target metal salt is prepared into an aqueous solution and mixed with MXene. After stirring at room temperature and adsorbing for 0.1 to 10 hours, a mineralizer is added and freeze-dried to obtain the single-atom-loaded MXene material. This invention provides a method for rapidly preparing metal single-atom two-dimensional materials on a group-rich and conductive MXene substrate, eliminating the high-temperature annealing process required for traditional single-atom preparation and maintaining good conductivity. However, this invention is limited by the randomness of the various functional groups on the MXene surface. The anchored metal atoms are in a state of variable and unstable coordination environment, which adversely affects the stability and activity of the single-atom-loaded MXene material in practical applications. To solve the above problems, Chinese invention patent application 202111529272.7 provides another method for preparing single-atom-loaded Mxene materials: Mxene is placed in an air atmosphere and heat-treated at 250-400°C for 1-4 hours to obtain oxygen-terminated Mxene (the surface is rich in oxygen functional groups), and then the oxygen-terminated Mxene is evenly dispersed in water, and then an iron-containing quantum dot dispersion is added and mixed, and ultrasonic treatment is performed to obtain the single-atom iron-loaded Mxene material. This invention stabilizes the surface functional groups of Mxene by heat treatment in an air atmosphere. The oxygen-functional group-rich Mxene formed is conducive to compounding with iron-containing quantum dots to generate iron single atoms with a stable coordination environment. However, this invention adds a heat treatment control step for the Mxene functional groups, which not only makes the preparation process more time-consuming and cumbersome, but also easily leads to excessive oxidation of the Mxene material, resulting in low purity of the prepared single-atom-loaded Mxene material and even causing the problem of preparation failure. Existing methods for preparing single-atom-loaded MXene materials have failed to achieve simple, efficient, and controllable preparation of single-atom-loaded MXene materials with a stable coordination environment. This significantly limits the practical scale-up, production, and application of these materials. Therefore, developing simple, feasible methods for efficiently preparing stable single-atom-loaded materials is crucial for the practical application of single-atom catalytic materials.

[0005] In summary, none of the existing methods can achieve the convenient and efficient preparation of single-atom stable load materials. Summary of the Invention

[0006] To overcome the shortcomings of existing single-atom-loaded materials, such as low efficiency and unstable metal coordination states, the present invention provides a highly efficient method for preparing single-atom-loaded MXene materials, inducing stable metal coordination states within a short period of time (10 minutes). This method is highly efficient and, compared to other single-atom-loaded MXene materials prepared by co-precipitation methods, exhibits a more stable metal coordination state due to the efficient plasma reduction effect.

[0007] Another object of the present invention is to provide a single-atom-loaded Mxene material obtained by the above preparation method.

[0008] Another object of the present invention is to provide applications of the above-mentioned single-atom-loaded MXene materials. The above-mentioned single-atom-loaded MXene materials can be used in the field of electrochemical catalysis, especially in the electrocatalytic oxygen evolution reaction.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] An efficient preparation method of a single-atom-loaded MXene material comprises the following steps:

[0011] (1) dissolving a metal salt corresponding to a target metal single atom in water to obtain a metal ion solution A;

[0012] (2) mixing the metal ion solution A obtained in step (1) with the MXene dispersion to obtain a suspension B;

[0013] (3) placing the suspension B obtained in step (2) in a gas-liquid discharge plasma reactor and performing a discharge reaction under an argon plasma atmosphere to obtain a suspension C;

[0014] (4) solid-liquid separation, freeze-drying the precipitate to obtain single-atom-loaded Mxene material.

[0015] In step (1), the metal salt is a metal chloride or a metal acetate, and the metal ion solution A is a solution obtained by dissolving the metal salt in water, with a concentration of 2 to 5 mg / mL based on the mass of the metal ion.

[0016] The metal ions used in step (1) for the preparation of single-atom-loaded Mxene materials include but are not limited to Mn, Fe, Co, Ni, Cu, Ru, Pd, In, Pt, etc.

[0017] In step (2), the MXene dispersion is obtained by dispersing the MXene material in water; the MXene material includes but is not limited to Ti3C2T x and Ti2CT x Material.

[0018] Step (2) specifically comprises slowly adding the metal ion solution A obtained in step (1) to the MXene dispersion, stirring at room temperature for 10 to 30 minutes to obtain a suspension B; the stirring speed is 100 to 400 rpm.

[0019] The concentration of the Mxene dispersion in step (2) is 5-10 mg / mL, and the mass ratio of the metal ions in the metal ion solution A to the Mxene material in the Mxene dispersion is (0.05-0.20):1.

[0020] The gas-liquid discharge plasma reactor described in step (3) comprises a needle-shaped hollow electrode, a reactor body, and a disc electrode. The reactor body is a cavity with openings at both ends, the bottom of the reactor body is closed by a disc electrode, and the needle-shaped hollow electrode is placed in the cavity of the reactor body through the opening at the upper end of the reactor body. The needle-shaped hollow electrode is provided with an air inlet. One end of the needle-shaped hollow electrode provided with the air inlet is connected to the negative electrode output end, and one end of the air outlet is placed in the reactor body; the disc electrode is connected to the positive electrode output end.

[0021] The reactor body is a cylindrical reactor made of polytetrafluoroethylene. The needle-shaped hollow electrode is made of stainless steel, and the disk electrode is a graphite electrode. The reactor body has a depth of 50 mm and an inner diameter of 60 mm. After the addition of mixed solution B, the depth of mixed solution B is 10 to 30 mm, and the distance between the liquid level of mixed solution B and the lower end of the needle-shaped hollow electrode is 2 to 5 mm.

[0022] In step (3), the argon gas flow rate in the needle-shaped hollow electrode is 5 to 20 mL / min, and the purity is 99.999%.

[0023] The plasma discharge of the present invention is a pulsed direct current discharge.

[0024] The discharge conditions in step (3) are: input voltage of 20 to 80 volts, output high voltage of 1 to 10 kilovolts, discharge frequency of 10 to 100 kilohertz, and treatment time of 1 to 10 minutes.

[0025] The centrifugation in step (4) is carried out 3 to 4 times at a low speed of 2000 to 5000 rpm for 3 to 5 minutes each time, and the supernatant is discarded and the precipitate is retained.

[0026] The drying in step (4) is freeze drying, the drying pressure is 0.36 to 1.5 Pascals, and the drying time is 24 to 48 hours.

[0027] The single-atom-loaded Mxene material obtained by the present invention maintains the few-layer morphology of the Mxene material, and does not have metal clusters and particles caused by excessive reduction.

[0028] The liquid-phase discharge plasma-induced single-atom loaded Mxene material is used in the field of electrochemical catalysis, especially in the electrocatalytic oxygen evolution reaction, especially in the iron-nickel alloy oxygen evolution electrode.

[0029] The principles of this invention are as follows: First, the surface of the MXene material in the few-layer MXene dispersion is rich in negatively charged functional groups such as O, Cl, and F. Upon addition of a metal cation solution, the metal cations attract these functional groups due to electrostatic forces and become evenly dispersed on the surface of the MXene material. Second, the gas-liquid discharge plasma system, unlike other reaction systems, generates a large number of solvated electrons under the interaction between the plasma and the liquid phase. Because these solvated electrons have a strong reducing potential (with a reduction potential of up to -2.8V in solution), they can easily and rapidly reduce most of the metal ions in the solution and anchor them to the MXene surface. Their coordination structure is more stable than that of materials not treated with the gas-liquid discharge plasma system. Through the combined action of these principles, MXene materials loaded with various metal atoms can be prepared using the liquid-phase discharge plasma system.

[0030] The present invention has the following advantages and beneficial effects compared to the prior art:

[0031] (1) The present invention adopts a liquid-phase discharge plasma system. Under the action of plasma and liquid phase, a large number of strongly reducing solvated electrons are generated, which can quickly and efficiently reduce most of the metal ions in the solution and anchor them on the surface of the MXene material. The utilization rate of metal ions is high and the coordination state of single atoms is more stable.

[0032] (2) The present invention can induce single atoms to be loaded on the surface of the MXene material through a simple one-step liquid-phase discharge plasma treatment method. The discharge reaction time can be controlled within 10 minutes. It is easy to operate, has a short process flow, high efficiency and reliability, and is easy to achieve large-scale production.

[0033] (3) The present invention proposes to use liquid-phase discharge plasma to induce the loading of various metal single atoms on the surface of different two-dimensional materials. The metal single atoms include but are not limited to Mn, Fe, Co, Ni, Cu, Ru, Pd, In, and Pt. The types of MXene include but are not limited to Ti3C2T x and Ti2CT x Materials have universal applicability and huge scalability potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the structure of the gas-liquid discharge plasma reactor used in the present invention;

[0035] Figure 2Schematic diagram of the gas-liquid discharge plasma reactor used in the present invention;

[0036] Figure 3 The XRD diffraction pattern of the S-Co-Ti2C material prepared in Example 1 and the original few-layer Ti2CT x diffraction patterns of materials;

[0037] Figure 4 This is a scanning electron microscope image of the S-Co-Ti2C material prepared in Example 1;

[0038] Figure 5 The original few-layer Ti2CT used in Examples 1-4 x Scanning electron microscope images of the materials;

[0039] Figure 6 This is a high-angle annular dark-field scanning transmission electron microscopy image of the S-Co-Ti2C material prepared in Example 1 corrected for spherical aberration;

[0040] Figure 7 Electrochemical test curves of the S-Co-Ti2C material and the iron-nickel alloy prepared in Example 1;

[0041] Figure 8 The XRD diffraction pattern of the S-Ni-Ti2C material prepared in Example 2 and the original few-layer Ti2CT x diffraction patterns of materials;

[0042] Figure 9 This is a scanning electron microscope image of the S-Ni-Ti2C material prepared in Example 2;

[0043] Figure 10 The XRD diffraction pattern of the S-Fe-Ti2C material prepared in Example 3 and the original few-layer Ti2CT x diffraction patterns of materials;

[0044] Figure 11 This is a scanning electron microscope image of the S-Fe-Ti2C material prepared in Example 3;

[0045] Figure 12 The XRD diffraction pattern of the S-Ru-Ti2C material prepared in Example 4 and the original few-layer Ti2CT x diffraction patterns of materials;

[0046] Figure 13 This is a scanning electron microscope image of the S-Ru-Ti2C material prepared in Example 4;

[0047] Figure 14 The XRD diffraction pattern of the S-Pt-Ti3C2 material prepared in Example 5 and the original few-layer Ti3C2T xdiffraction patterns of materials;

[0048] Figure 15 This is a scanning electron microscope image of the S-Pt-Ti3C2 material prepared in Example 5;

[0049] Figure 16 The original few-layer Ti3C2T in Examples 5-6 x Scanning electron microscope images of the materials;

[0050] Figure 17 The XRD diffraction pattern of the S-Ni-Ti3C2 material prepared in Example 6 and the original few-layer Ti3C2T x diffraction patterns of materials;

[0051] Figure 18 This is a scanning electron microscope image of the S-Ni-Ti3C2 material prepared in Example 6;

[0052] Figure 19 The XRD diffraction pattern of the reaction product S-Co-Ti2C-D material in Comparative Example 1 and the original few-layer Ti2CT x diffraction patterns of materials;

[0053] Figure 20 This is a scanning electron microscope image of the reaction product S-Co-Ti2C-D material in Comparative Example 1;

[0054] Figure 21 These are the electrochemical test curves of the S-Co-Ti2C-D material and the iron-nickel alloy in Comparative Example 1. DETAILED DESCRIPTION

[0055] For a better understanding of the present invention, the present invention will be further described below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0056] like Figure 1 and Figure 2 As shown, the gas-liquid discharge plasma reactor used in the present invention comprises an upper needle-shaped hollow electrode 1, a reactor body 2, and a lower disk electrode 3. The upper needle-shaped hollow electrode 1 and the lower disk electrode 3 are made of stainless steel and graphite, respectively. The reactor body 2 is a cylindrical reactor made of polytetrafluoroethylene, with a depth of 50 mm and an inner wall diameter of 60 mm. The mixed solution to be reacted is added to a depth of 10 to 30 mm, and the distance between the liquid surface of the mixed solution and the upper needle-shaped hollow electrode 1 is 2 to 5 mm, which is the discharge distance or discharge gap. The argon gas flow rate within the upper needle-shaped hollow electrode 1 is 5 to 20 ml / min, with a purity of 99.999%.

[0057] The plasma power supply used in this invention is a model CTP-2000K, manufactured by Nanjing Suman Plasma Technology Co., Ltd. To maximize the characteristics of DC discharge, a rectifier is used to convert the plasma power supply's output signal into a pulsed DC signal. The positive output terminal of the rectifier is connected to the lower disk electrode, and the negative output terminal of the rectifier is connected to the upper needle-shaped hollow electrode.

[0058] The Mxene material in the embodiment is prepared by the following method:

[0059] S1: dissolving LiF powder in a hydrochloric acid solution and slowly adding it to a Ti3AlC2 or Ti2AlC powder precursor under stirring to obtain a mixed solution A; the mass concentration of the hydrochloric acid is 3-27%; the amount of the LiF powder is 2.5-10% of the mass of the hydrochloric acid solution; the Ti3AlC2 powder precursor is a powder of 200-400 mesh and 99% purity, and the amount of the Ti3AlC2 precursor is 30-200% of the mass of the LiF powder;

[0060] S2: transferring the mixed solution A obtained in step (1) to a gas-liquid discharge plasma reactor, and performing a discharge reaction in an argon plasma atmosphere for 5 to 45 minutes to obtain a mixed solution B; during the discharge reaction, controlling the discharge current to be 500 to 1500 mA, the input voltage to be 20 to 80 V, the output high voltage to be 10 to 30 KV, the discharge frequency to be 5 to 40 KHz, the discharge power to be 30 to 90 W, and the discharge treatment time to be 5 to 45 minutes;

[0061] S3: Centrifuge the mixed solution B to collect the solid. After multiple centrifugations, collect the upper black precipitate and dry it to obtain Ti3C2T x Mxene material or Ti2CT x Mxene material.

[0062] In the preparation of MXene materials, the gas-liquid discharge plasma reactor comprises an upper electrode, a dielectric cover, a reactor body, a gas inlet, a gas outlet, and a lower electrode. The reactor body is a sealed, hollow, disc-shaped reactor with a gas inlet and outlet. The upper end of the hollow reactor body is fitted with a dielectric cover. Both the dielectric cover and the reactor body are made of polytetrafluoroethylene. The upper and lower electrodes are made of stainless steel. The hollow reactor body has a depth of 6 mm. After the addition of mixed solution A, the depth of mixed solution A is 1-2 mm, and the distance between the liquid level of mixed solution A and the bottom surface of the dielectric cover is 4-5 mm. The argon gas flow rate is 5-20 ml / min, with a purity of 99.999%.

[0063] Example 1

[0064] (1) Analytical pure CoCl2·6H2O (purity 99.5%, 40.38 mg) was dissolved in 5 ml of deionized water to make solution A, the concentration of which was calculated based on Co 2+ The mass is 2 mg / ml;

[0065] (2) Solution A was slowly added to 20 ml of Ti2CT under magnetic stirring at 200 rpm. x Mxene dispersion (Ti3C2T x The MXene material was dispersed in water to obtain a suspension B, wherein the concentration of the MXene dispersion was 5 mg / mL, and the suspension B was obtained after stirring for 20 minutes, wherein Co 2+ Ti2CT in MXene dispersion x The mass ratio is 0.1:1;

[0066] (3) The suspension B obtained in step (2) was transferred to the main body of the gas-liquid discharge plasma reactor, and the distance between the lower end of the needle-shaped hollow metal electrode and the liquid surface of the suspension B was controlled to be 3 mm, which was recorded as the discharge distance of 3 mm. After fixing, the needle-shaped electrode was controlled to flow high-purity argon gas (10 ml / min, purity 99.999%) directly to the liquid surface; the upper end of the needle-shaped hollow metal electrode was connected to the negative output of the rectifier, and the lower end of the graphite electrode was connected to the positive output of the rectifier. The plasma power was turned on, and the reaction was continued stably for 10 minutes under the conditions of input voltage 40 V, output high voltage 5 kV, and discharge frequency 34.5 kHz to obtain a black suspension C;

[0067] (4) Using a centrifuge, the black suspension C obtained in step (3) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 3500 rpm for 5 minutes. The supernatant was discarded and the black precipitate D was retained. The black precipitate D was freeze-dried at a low pressure of 0.6 Pascal for 48 hours to obtain pure cobalt single-atom-loaded Ti2CT x Mxene material, denoted as S-Co-Ti2C.

[0068] The S-Co-Ti2C material was subjected to energy spectrum analysis. The results are shown in Table 1. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Co element was also detected with a mass percentage of 3.78% and an atomic percentage of 1.63%, indicating that Co was successfully introduced into Ti2C x In Mxene materials.

[0069] Figure 3 The XRD diffraction pattern of the S-Co-Ti2C material prepared in Example 1 and the original few-layer Ti2CT x The diffraction pattern of the material shows that after treatment, the S-Co-Ti2C material retains the original few-layer Ti2CT xThe diffraction peaks of the material did not appear, and no new diffraction peaks appeared, proving that the reduction treatment did not reduce the Co ions to a metallic state or its oxide state. Figure 4 This is the scanning electron microscope image of the S-Co-Ti2C material prepared in Example 1, which is different from the original few-layer Ti2CT x Compared with the material ( Figure 5 ), no obvious agglomeration of metal particles was observed on the surface of S-Co-Ti2C. Figure 6 The high-angle annular dark field scanning transmission electron microscopy image of the S-Co-Ti2C material prepared in Example 1, which was corrected for spherical aberration, shows the appearance of white bright spots, which is direct evidence of the existence of Co single atoms with higher atomic numbers. Therefore, the above results show that Co in Ti2CT x MXene exists in a single-atom state in the material.

[0070] Table 1 Cobalt single atom-loaded Ti2CT x Energy spectrum analysis results of Mxene materials

[0071] Element type atomic number Characteristic X-rays Element mass percentage Element atomic percentage C 6 K 7.79 16.50 O 8 K 29.88 47.51 F 9 K 3.23 4.32 Cl 17 K 3.49 2.50 Ti 22 K 51.83 27.54 Co 27 K 3.78 1.63

[0072] Electrocatalytic performance test:

[0073] The S-Co-Ti2C material prepared in this embodiment is uniformly dispersed in a Nafion aqueous solution to obtain a catalyst dispersion. A small amount of the above catalyst dispersion is dropped onto a porous iron-nickel alloy conductive substrate and dried as an oxygen evolution reaction electrode. A three-electrode system is used, with the oxygen evolution reaction electrode as the working electrode, a platinum sheet as the counter electrode, mercury oxide as the doping electrode, and 1 mol / L potassium hydroxide as the electrolyte. Electrochemical tests are performed on a Gamry electrochemical workstation to characterize the catalytic activity of the oxygen evolution reaction of the S-Co-Ti2C material. The specific test parameters are as follows: linear sweep voltammetry, a scan rate of 5 mV / s, and a scan voltage window of 1.2 to 1.6 volts (relative to the reversible hydrogen electrode). The test results are as follows: Figure 7 As shown. Figure 7 It can be seen that when the porous iron-nickel alloy is loaded with the S-Co-Ti2C material prepared by the present invention, the electrocatalytic activity is significantly improved, and the overpotential at 10 mA / cm2 is only 251 mV, which is less than 293 mV of the porous iron-nickel alloy.

[0074] It can be seen that using liquid phase discharge plasma technology, stable Co single atoms can be induced in Ti2CT within 10 minutes. x The S-Co-Ti2C material prepared by the present invention has a synergistic effect with the porous iron-nickel alloy, which can effectively improve the thermodynamic conditions of the electrocatalytic oxygen evolution reaction of the iron-nickel alloy and has broad application prospects in the field of electrochemical catalysis.

[0075] Example 2

[0076] (1) Analytical pure NiC4H6O4·4H2O (purity 99.5%, 63.60 mg) was dissolved in 5 ml of deionized water to make solution A, the concentration of which was based on Ni 2+ The mass is calculated as 3 mg / ml;

[0077] (2) Solution A was slowly added to 30 ml of Ti2CT under magnetic stirring at 300 rpm. x In the Mxene dispersion, the concentration of the Mxene dispersion was 10 mg / ml, and after stirring for 10 minutes, suspension B was obtained, wherein Ni 2+ Ti2CT in MXene dispersion x The mass ratio is 0.05:1;

[0078] (3) The suspension B obtained in step (2) was transferred to the main body of the gas-liquid discharge plasma reactor, and the distance between the needle-shaped hollow metal electrode and the liquid surface of the suspension B was controlled to be 5 mm, which was recorded as the discharge distance of 5 mm. After fixing, the needle-shaped electrode was controlled to flow high-purity argon gas (15 ml / min, purity 99.999%) directly to the liquid surface; the upper end of the needle-shaped hollow metal electrode was connected to the negative output of the rectifier, and the lower end of the graphite electrode was connected to the positive output of the rectifier. The plasma power was turned on, and the reaction was continued stably for 8 minutes under the conditions of input voltage of 20 V, output high voltage of 1 kV, and discharge frequency of 10 kHz to obtain a black suspension C;

[0079] (4) Using a centrifuge, the black suspension C obtained in step (3) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 4500 rpm for 4 minutes. The supernatant was discarded and the black precipitate D was retained. The black precipitate D was freeze-dried at a low pressure of 1 Pascal for 36 hours to obtain pure nickel single-atom-loaded Ti2CT x Mxene material, denoted as S-Ni-Ti2C.

[0080] The S-Ni-Ti2C material was subjected to energy spectrum analysis. The results are shown in Table 2. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Ni was also detected with a mass percentage of 2.65% and an atomic percentage of 1.02%, indicating that Ni was successfully introduced into Ti2C x In Mxene materials.

[0081] Figure 8 The XRD diffraction pattern of the S-Ni-Ti2C material prepared in Example 2 and the original few-layer Ti2CT x The diffraction pattern of the material shows that after treatment, the S-Ni-Ti2C material retains the original few-layer Ti2CT xThe diffraction peaks of the material did not appear, and no new diffraction peaks appeared, proving that the reduction treatment did not reduce the Ni ions to a metallic state or its oxide state. Figure 9 This is the scanning electron microscope image of the S-Ni-Ti2C material prepared in Example 2, which is different from the original few-layer Ti2CT x Compared with the material ( Figure 5 ), no obvious metal particle agglomeration was observed on the surface of S-Ni-Ti2C. The above results show that Ni x MXene exists in a single-atom state in the material.

[0082] Table 2 Ti2CT supported by nickel single atoms x Energy spectrum analysis results of Mxene materials

[0083] Element type atomic number Characteristic X-rays Element mass percentage Element atomic percentage C 6 K 15.85 29.87 O 8 K 27.96 39.56 F 9 K 4.87 5.80 Cl 17 K 4.42 2.82 Ti 22 K 44.26 20.93 Ni 28 K 2.65 1.02

[0084] It can be seen that using liquid phase discharge plasma technology, stable Ni single atoms can be induced on Ti2CT within 8 minutes. x Efficient loading on Mxene materials. The S-Ni-Ti2C material prepared in this example has a synergistic effect with the porous iron-nickel alloy. The electrochemical test results are similar to those in Example 1. It can effectively improve the thermodynamic conditions of the electrocatalytic oxygen evolution reaction of the iron-nickel alloy and has broad application prospects in the field of electrochemical catalysis.

[0085] Example 3

[0086] (1) Analytical pure FeCl2·4H2O (purity 99.5%, 35.60 mg) was dissolved in 5 ml of deionized water to make solution A, the concentration of which was based on Fe 2+ The mass is 2 mg / ml;

[0087] (2) Solution A was slowly added to 40 ml of Ti2CT under magnetic stirring at 400 rpm. x The MXene dispersion was prepared at a concentration of 5 mg / ml and stirred for 30 minutes to obtain suspension B, wherein Fe 2+ Ti2CT in MXene dispersion x The mass ratio is 0.05:1;

[0088] (3) The suspension B obtained in step (2) was transferred to the main body of the gas-liquid discharge plasma reactor, and the distance between the needle-shaped hollow metal electrode and the liquid surface of the suspension B was controlled to be 4 mm, which was recorded as the discharge distance of 4 mm. After fixing, the needle-shaped electrode was controlled to flow high-purity argon gas (5 ml / min, purity 99.999%) directly to the liquid surface; the upper end of the needle-shaped hollow metal electrode was connected to the negative output of the rectifier, and the lower end of the graphite electrode was connected to the positive output of the rectifier. The plasma power was turned on, and the reaction was continued stably for 9 minutes under the conditions of input voltage 30 V, output high voltage 4 kV, and discharge frequency 20 kHz to obtain a black suspension C;

[0089] (4) Using a centrifuge, the black suspension C obtained in step (3) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 5000 rpm for 3 minutes. The supernatant was discarded and the black precipitate D was retained. The black precipitate D was freeze-dried at a low pressure of 1.5 Pascal for 24 hours to obtain pure iron single-atom-loaded Ti2CT x Mxene material, denoted as S-Fe-Ti2C.

[0090] The S-Fe-Ti2C material was subjected to energy spectrum analysis. The results are shown in Table 3. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Ni was also detected with a mass percentage of 0.89% and an atomic percentage of 0.37%, indicating that Fe was successfully introduced into Ti2C x In Mxene materials.

[0091] Figure 10 The XRD diffraction pattern of the S-Fe-Ti2C material prepared in Example 3 and the original few-layer Ti2CT x The diffraction pattern of the material shows that after treatment, the S-Fe-Ti2C material retains the original few-layer Ti2CT x The diffraction peaks of the material did not appear, and no new diffraction peaks appeared, proving that the reduction treatment did not reduce the Fe ions to a metallic state or its oxide state. Figure 11 This is the scanning electron microscope image of the S-Fe-Ti2C material prepared in Example 3, which is different from the original few-layer Ti2CT x Compared with the material ( Figure 5 ), no obvious metal particle agglomeration was observed on the surface of S-Fe-Ti2C. The above results show that Fe x MXene exists in a single-atom state in the material.

[0092] Table 3 Ti2CT supported by single iron atoms x Energy spectrum analysis results of Mxene materials

[0093] Element type atomic number Characteristic X-rays Element mass percentage Element atomic percentage C 6 K 16.17 31.14 O 8 K 26.13 37.78 F 9 K 3.60 4.38 Cl 17 K 3.60 2.35 Ti 22 K 49.62 23.98 Fe 28 K 0.89 0.37

[0094] It can be seen that using liquid phase discharge plasma technology, stable Fe single atoms can be induced in Ti2CT within 8 minutes. x Efficient loading on Mxene materials. The S-Fe-Ti2C material prepared in this example has a synergistic effect with the porous iron-nickel alloy. The electrochemical test results are similar to those in Example 1. It can effectively improve the thermodynamic conditions of the electrocatalytic oxygen evolution reaction of the iron-nickel alloy and has broad application prospects in the field of electrochemical catalysis.

[0095] Example 4

[0096] (1) Analytical pure RuCl3·xH2O (purity 99.5%, 98.51 mg) was dissolved in 12 ml of deionized water to make solution A, the concentration of which was based on Ru 3+ The mass is calculated as 4 mg / ml;

[0097] (2) Solution A was slowly added to 30 ml of Ti2CT under magnetic stirring at 400 rpm. x In the Mxene dispersion, the concentration of the Mxene dispersion is 8 mg / ml, after stirring for 15 minutes, suspension B is obtained, wherein Ru 3+ Ti2CT in MXene dispersion x The mass ratio is 0.2:1;

[0098] (3) The suspension B obtained in step (2) was transferred to the main body of the gas-liquid discharge plasma reactor, and the distance between the needle-shaped hollow metal electrode and the liquid surface of the suspension B was controlled to be 2 mm, which was recorded as the discharge distance of 2 mm. After fixing, the needle-shaped electrode was controlled to flow high-purity argon gas (10 ml / min, purity 99.999%) directly to the liquid surface; the upper end of the needle-shaped hollow metal electrode was connected to the negative output of the rectifier, and the lower end of the graphite electrode was connected to the positive output of the rectifier. The plasma power supply was turned on, and the reaction was continued stably for 1 minute under the conditions of input voltage 80 V, output high voltage 10 kV, and discharge frequency 60 kHz to obtain a black suspension C;

[0099] (4) Using a centrifuge, the black suspension C obtained in step (3) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 4000 rpm for 4 minutes. The supernatant was discarded and the black precipitate D was retained. The black precipitate D was freeze-dried at a low pressure of 0.36 Pascal for 48 hours to obtain pure ruthenium single atom-loaded Ti2CT x Mxene material, denoted as S-Ru-Ti2C.

[0100] The S-Ru-Ti2C material was subjected to energy spectrum analysis. The results are shown in Table 4. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Ru was also detected with a mass percentage of 5.25% and an atomic percentage of 2.17%, indicating that Ni was successfully introduced into Ti2C x In Mxene materials.

[0101] Figure 12 The XRD diffraction pattern of the S-Ru-Ti2C material prepared in Example 4 and the original few-layer Ti2CT x The diffraction pattern of the material shows that after treatment, the S-Ru-Ti2C material retains the original few-layer Ti2CT x The diffraction peaks of the material did not appear, and no new diffraction peaks appeared, proving that the reduction treatment did not reduce the Ru ions to a metallic state or its oxide state. Figure 13 This is the scanning electron microscope image of the S-Ru-Ti2C material prepared in Example 4, which is different from the original few-layer Ti2CT x Compared with the material ( Figure 5 ), no obvious metal particle agglomeration was observed on the surface of S-Ru-Ti2C. The above results show that Ru x MXene exists in a single-atom state in the material.

[0102] Table 4 Ruthenium single atom loaded Ti2CT x Energy spectrum analysis results of Mxene materials

[0103]

[0104]

[0105] It can be seen that using liquid phase discharge plasma technology, stable Ru single atoms can be induced on Ti2CT within 1 minute. x Efficient loading on Mxene materials. The S-Ru-Ti2C material prepared in this example has a synergistic effect with the porous iron-nickel alloy. The electrochemical test results are similar to those in Example 1. It can effectively improve the thermodynamic conditions of the electrocatalytic oxygen evolution reaction of the iron-nickel alloy and has broad application prospects in the field of electrochemical catalysis.

[0106] Example 5

[0107] (1) Analytical pure H2PtCl6·6H2O (purity 99.5%, 26.55 mg) was dissolved in 5 ml of deionized water to make solution A, the concentration of which was calculated based on the Pt 3+ The mass is 2 mg / ml;

[0108] (2) Solution A was slowly added to 20 ml of Ti3C2T under magnetic stirring at 300 rpm.x In the Mxene dispersion, the concentration of the Mxene dispersion was 10 mg / ml, and after stirring for 10 minutes, suspension B was obtained, in which Pt 3+ Ti2CT in MXene dispersion x The mass ratio is 0.05:1;

[0109] (3) The suspension B obtained in step (2) was transferred to the main body of the gas-liquid discharge plasma reactor, and the distance between the needle-shaped hollow metal electrode and the liquid surface of the suspension B was controlled to be 5 mm, which was recorded as the discharge distance of 5 mm. After fixing, the needle-shaped electrode was controlled to flow high-purity argon gas (20 ml / min, purity 99.999%) directly to the liquid surface; the upper end of the needle-shaped hollow metal electrode was connected to the negative output of the rectifier, and the lower end of the graphite electrode was connected to the positive output of the rectifier. The plasma power supply was turned on, and the reaction was continued stably for 1 minute under the conditions of input voltage 80 V, output high voltage 10 kV, and discharge frequency 50 kHz to obtain a black suspension C;

[0110] (4) Using a centrifuge, the black suspension C obtained in step (3) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 4500 rpm for 4 minutes. The supernatant was discarded and the black precipitate D was retained. The black precipitate D was freeze-dried at a low pressure of 0.65 Pascal for 48 hours to obtain pure Ti3C2T3 supported by single platinum atoms. x Mxene material, denoted as S-Pt-Ti3C2.

[0111] The S-Pt-Ti3C2 material was subjected to energy spectrum analysis. The results are shown in Table 5. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Pt element was also detected with a mass percentage of 0.23% and an atomic percentage of 0.03%, indicating that Pt was successfully introduced into the Ti3C2T x In Mxene materials.

[0112] Figure 14 The XRD diffraction pattern of the S-Pt-Ti3C2 material prepared in Example 5 and the original few-layer Ti2CT x The diffraction pattern of the material shows that after treatment, the S-Pt-Ti3C2 material retains the original few-layer Ti2CT x The diffraction peaks of the material did not appear, and no new diffraction peaks appeared, proving that the reduction treatment did not reduce the Pt ions to a metallic state or its oxide state. Figure 15 This is the scanning electron microscope image of the S-Pt-Ti3C2 material prepared in Example 5, which is different from the original few-layer Ti3C2T x Compared with the material ( Figure 16 ), no obvious metal particle agglomeration was observed on the surface of S-Ni-Ti3C2. The above results show that Pt xMXene exists in a single-atom state in the material.

[0113] Table 5 Ti3C2T supported by single platinum atoms x Energy spectrum analysis results of Mxene materials

[0114] Element type atomic number Characteristic X-rays Element mass percentage Element atomic percentage C 6 K 24.01 46.20 O 8 K 13.48 19.47 F 9 K 5.09 6.19 Cl 17 K 3.03 1.97 Ti 22 K 54.16 26.14 Pt 78 L 0.23 0.03

[0115] It can be seen that using liquid phase discharge plasma technology, stable Pt single atoms can be induced in Ti3C2T within 1 minute. x Efficient loading on Mxene materials. The S-Ni-Ti3C2 material prepared in this example has a synergistic effect with the porous iron-nickel alloy. The electrochemical test results are similar to those in Example 1. It can effectively improve the thermodynamic conditions of the electrocatalytic oxygen evolution reaction of the iron-nickel alloy and has broad application prospects in the field of electrochemical catalysis.

[0116] Example 6

[0117] (1) Analytical pure NiC4H6O4·4H2O (purity 99.5%, 63.60 mg) was dissolved in 5 ml of deionized water to make solution A, the concentration of which was based on Ni 2+ The mass is calculated as 3 mg / ml;

[0118] (2) Solution A was slowly added to 25 ml of Ti3C2T under magnetic stirring at 300 rpm. x The MXene dispersion was 6 mg / ml in concentration and stirred for 10 minutes to obtain suspension B, in which Ni 2+ Ti3C2T in MXene dispersion x The mass ratio is 0.1:1;

[0119] (3) The suspension B obtained in step (2) was transferred to the main body of the gas-liquid discharge plasma reactor, and the distance between the needle-shaped hollow metal electrode and the liquid surface of the suspension B was controlled to be 3 mm, which was recorded as the discharge distance of 3 mm. After fixing, the needle-shaped electrode was controlled to flow high-purity argon gas (15 ml / min, purity 99.999%) directly to the liquid surface; the upper needle-shaped hollow metal electrode 1 was connected to the negative output of the rectifier, and the lower graphite electrode 3 was connected to the positive output of the rectifier. The plasma power supply was turned on, and the reaction was continued stably for 10 minutes under the conditions of input voltage of 20 V, output high voltage of 1 kV, and discharge frequency of 10 kHz to obtain a black suspension C;

[0120] (4) Using a centrifuge, the black suspension C obtained in step (3) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 4500 rpm for 4 minutes. The supernatant was discarded and the black precipitate D was retained. The black precipitate D was freeze-dried at a low pressure of 0.8 Pascal for 36 hours to obtain pure nickel single-atom-loaded Ti3C2T x Mxene material, recorded as S-Ni-Ti3C2.

[0121] The S-Ni-Ti3C2 material was subjected to energy spectrum analysis. The results are shown in Table 6. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Ni was also detected with a mass percentage of 3.00% and an atomic percentage of 1.40%, indicating that Ni was successfully introduced into the Ti3C2T x In Mxene materials.

[0122] Figure 17 The XRD diffraction pattern of the S-Ni-Ti3C2 material prepared in Example 6 and the original few-layer Ti3C2T x The diffraction pattern of the material shows that after treatment, the S-Ni-Ti3C2 material retains the original few-layer Ti3C2T x The diffraction peaks of the material did not appear, and no new diffraction peaks appeared, proving that the reduction treatment did not reduce the Ni ions to a metallic state or its oxide state. Figure 18 This is the scanning electron microscope image of the S-Ni-Ti3C2 material prepared in Example 6, which is different from the original few-layer Ti3C2T x Compared with the material ( Figure 16 ), no obvious metal particle agglomeration was observed on the surface of S-Ni-Ti3C2. The above results show that Ni x MXene exists in a single-atom state in the material.

[0123] Table 6 Nickel single atom supported Ti3C2T x Energy spectrum analysis results of Mxene materials

[0124] Element type atomic number Characteristic X-rays Element mass percentage Element atomic percentage C 6 K 12.68 28.92 O 8 K 14.53 24.88 F 9 K 4.87 7.02 Cl 17 K 3.09 2.39 Ti 22 K 61.84 35.39 Ni 28 K 3.00 1.40

[0125] It can be seen that using liquid phase discharge plasma technology, stable Ni single atoms can be induced in Ti3C2T within 10 minutes. x Efficient loading on Mxene materials. The S-Ni-Ti3C2 material prepared in this example has a synergistic effect with the porous iron-nickel alloy. The electrochemical test results are similar to those in Example 1. It can effectively improve the thermodynamic conditions of the electrocatalytic oxygen evolution reaction of the iron-nickel alloy and has broad application prospects in the field of electrochemical catalysis.

[0126] Comparative Example 1

[0127] (1) Analytical pure CoCl2·6H2O (purity 99.5%, 40.38 mg) was dissolved in 5 ml of deionized water to make solution A, the concentration of which was calculated based on Co 2+ The mass is 2 mg / ml;

[0128] (2) Solution A was slowly added to 20 ml of homemade Ti2CT under magnetic stirring at 200 rpm. x In the Mxene dispersion, the concentration of the Mxene dispersion was 5 mg / ml, and after stirring for 20 minutes, a black suspension B was obtained, wherein Co 2+ Ti2CT in MXene dispersion x The mass ratio is 0.1:1;

[0129] (3) Using a centrifuge, the black suspension B obtained in step (2) was centrifuged and washed with deionized water. The centrifugal washing was repeated 4 times, each time at a speed of 3500 rpm for 5 minutes. The supernatant was discarded and the black precipitate C was retained. The black precipitate C was freeze-dried at a low pressure of 0.6 Pascal for 48 hours to obtain pure cobalt single-atom-loaded Ti2CT x Mxene material, denoted as S-Co-Ti2C-D.

[0130] The S-Co-Ti2C-D material was subjected to energy spectrum analysis. The results are shown in Table 7. In addition to Ti, C and their surface adsorbed functional groups (F, Cl, O), Co was also detected with a mass percentage of 5.19% and an atomic percentage of 2.13%, indicating that Co can be introduced into Ti2CT without plasma reduction treatment. x In Mxene materials.

[0131] Figure 19 The XRD diffraction pattern of the S-Co-Ti2C-D material prepared in Comparative Example 1 and the original few-layer Ti2CT x The diffraction pattern of the material shows that the S-Co-Ti2C-D material retains the original few-layer Ti2CT x The diffraction peaks of the material are the same and no new diffraction peaks appear, which proves that Co does not exist in the form of metal or oxidation in the Mxene material. Figure 20 The SEM image of the S-Co-Ti2C material prepared in Comparative Example 1 is compared with the original few-layer Ti2CT x Compared with the material ( Figure 5 ), no obvious metal particle agglomeration was observed on the surface of S-Co-Ti2C-D. Therefore, the above results show that without plasma reduction treatment, Co x MXene materials also exist in a single-atom state.

[0132] Table 7 Energy spectrum analysis results of materials prepared in Comparative Example 1

[0133] Element type atomic number Characteristic X-rays Element mass percentage Element atomic percentage C 6 K 14.08 28.19 O 8 K 21.40 32.38 F 9 K 8.25 10.51 Cl 17 K 5.46 3.74 Ti 22 K 45.61 23.06 Co 27 K 5.19 2.13

[0134] The S-Co-Ti2C-D material prepared in this comparative example is uniformly dispersed in a Nafion aqueous solution to obtain a catalyst dispersion. A small amount of the above catalyst dispersion is dropped onto a porous iron-nickel alloy conductive substrate and dried as an oxygen evolution reaction electrode. A three-electrode system is used, with the oxygen evolution reaction electrode as the working electrode, a platinum sheet as the counter electrode, mercury oxide as the mixed electrode, and 1 mol / L potassium hydroxide as the electrolyte. Electrochemical tests are performed on a Gamry electrochemical workstation to characterize the catalytic activity of the oxygen evolution reaction of the S-Co-Ti2C-D material. The specific test parameters are as follows: linear sweep voltammetry, a scan rate of 5 mV / s, and a scan voltage window of 1.2 to 1.6 volts (relative to the reversible hydrogen electrode). The test results are as follows: Figure 21 As shown. Figure 21 It can be seen that when the porous iron-nickel alloy is loaded with S-Co-Ti2C-D material that has not been treated with plasma reduction, the electrocatalytic activity is not improved.

[0135] It can be seen that Co single atom-loaded Ti2CT can be prepared even without plasma reduction treatment. x However, there is no synergistic effect between the prepared S-Co-Ti2C-D material and the porous Fe-Ni alloy, and it cannot effectively improve the thermodynamic conditions of the Fe-Ni alloy electrocatalytic oxygen evolution reaction. This is due to the unstable coordination environment of the Co single atom without plasma reduction treatment.

Claims

1. An efficient preparation method of single-atom-loaded MXene materials, characterized by: The following steps are involved: (1) Dissolving the metal salt corresponding to the target metal single atom in water to obtain metal ion solution A; (2) The metal ion solution A obtained in step (1) is mixed with the MXene dispersion to obtain a suspension B; the mass ratio of the metal ions in the metal ion solution A to the MXene in the MXene dispersion is (0.05-0.20):1; (3) placing the suspension B obtained in step (2) in a gas-liquid discharge plasma reactor, and performing a discharge reaction in an argon plasma atmosphere to obtain a suspension C; the discharge reaction conditions in step (3) are: an input voltage of 20 to 80 volts, an output high voltage of 1 to 10 kilovolts, a discharge frequency of 10 to 100 kilohertz, and a treatment time of 1 to 10 minutes; (4) Solid-liquid separation, freeze-drying the precipitate to obtain metal single atom-loaded Mxene material.

2. The efficient preparation method of single-atom-loaded MXene material according to claim 1, characterized in that: The metal salt is a salt corresponding to a metal ion, and the metal ion includes one or more of Mn, Fe, Co, Ni, Cu, Ru, Pd, In, and Pt; The distance between the liquid surface of the suspension B and the needle-shaped hollow electrode of the discharge plasma reactor is 2 to 5 mm; The argon gas flow rate in the needle-shaped hollow electrode in the reactor is 5-20 ml / min.

3. The efficient preparation method of single-atom-loaded MXene material according to claim 1, characterized in that: The gas-liquid discharge plasma reactor comprises a needle-shaped hollow electrode, a reactor body and a disk electrode; The reactor body is a cavity with two ends open, and the disc electrode is arranged at the lower end of the reactor body to seal the lower end of the reactor body; The needle-shaped hollow electrode is provided with an air inlet and an air outlet, the air outlet is arranged at the top end of the needle-shaped hollow electrode, and the air inlet is arranged at the other end of the electrode; the needle-shaped hollow electrode is placed in the cavity of the reactor body through the open end of the reactor body.

4. The efficient preparation method of single-atom-loaded MXene material according to claim 3, characterized in that: The reactor body is a cylindrical reactor made of polytetrafluoroethylene; the needle-shaped hollow electrode is made of stainless steel, and the disk electrode is a graphite electrode; the depth of the reactor body is 50 mm and the inner wall diameter is 60 mm. After the suspension B is added, the depth of the suspension B is 10-30 mm, and the distance between the liquid surface of the suspension B and the needle-shaped hollow electrode is 2-5 mm.

5. The efficient preparation method of single-atom-loaded MXene material according to claim 1, characterized in that: The metal salt is a metal chloride or acetate, and the metal ion solution A is a solution obtained by dissolving the metal salt in water, with a concentration of 2 to 5 mg / ml based on the mass of the metal ion; The MXene dispersion is obtained by dispersing MXene materials in water. The types of MXene include Ti3C2T x and / or Ti2CT x Material; The concentration of the MXene dispersion is 5~10 mg / mL.

6. The efficient preparation method of single-atom-loaded MXene material according to claim 1, characterized in that: The solid-liquid separation in step (4) refers to centrifugation; the centrifugation conditions are: centrifugation at a speed of 2000-5000 rpm for 3-4 times, 3-5 minutes per time, discarding the supernatant and retaining the precipitate; in step (4), the drying is freeze drying, the drying pressure is 0.36-1.5 Pascal, and the drying time is 24-48 hours.

7. The efficient preparation method of single-atom-loaded MXene material according to claim 1, characterized in that: The specific steps of step (2) are as follows: slowly adding the metal ion solution A to the MXene dispersion, stirring at room temperature for 10 to 30 minutes to obtain a suspension B; the stirring is magnetic stirring, the speed is 100 to 400 rpm, and the stirring time is 10 to 30 minutes.

8. A single-atom-loaded Mxene material obtained by the preparation method according to any one of claims 1 to 7.

9. Application of the single-atom-loaded Mxene material according to claim 8 in the field of electrochemical catalysis.

10. The use according to claim 9, characterized in that: The single-atom-loaded Mxene material is used for electrocatalytic oxygen evolution reaction.

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