Metal atom doped needle-shaped manganese oxide electrocatalyst as well as preparation method and application thereof

Abstract

The invention discloses a metal atom doped needle-shaped manganese oxide electrocatalyst as well as a preparation method and application thereof, and relates to the technical field of electrocatalysts. According to the method, a one-step hydrothermal method is adopted to directly grow metal atom-doped needle-shaped manganese oxide on a carbon paper substrate, only precursor metal ion compounds and potassium permanganate need to be mixed in the preparation process, hydrothermal reaction and post-treatment are needed, and multi-step synthesis or complex intercalation is not needed. According to the invention, lattice distortion and oxygen vacancy formation are induced through heterogeneous atom doping (such as Ru, Ni, Co and the like), active sites on the surface of the catalyst are stabilized, and the number of the active sites is increased, so that the electronic structure and reaction kinetics are optimized, and the electrocatalytic activity of the catalyst is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrocatalysts, in particular to a metal atom doped needle-shaped manganese oxide electrocatalyst and a preparation method and application thereof. BACKGROUND

[0002] The global energy demand is growing, and therefore the development of efficient energy storage and conversion technologies is crucial for the sustainable development of mankind. Among various technologies, electrochemical water splitting technology has become a promising technology for large-scale production of hydrogen, which is an extremely attractive sustainable energy. Electrocatalytic water splitting involves cathodic hydrogen evolution (HER) and anodic oxygen evolution reaction (OER), which have slow reaction kinetics and large dynamic overpotential. In order to obtain ideal electrocatalytic activity, both reactions require noble metal catalysts (HER reaction uses platinum, and OER reaction uses IrO2 / RuO2). However, due to the high cost and scarcity of platinum and iridium, and the lack of durability during long-term operation, it is not realistic to widely use these catalysts for industrial-scale water splitting.

[0003] In the past few decades, manganese oxides have become ideal candidates for electrocatalytic water splitting due to their natural abundance, low toxicity, and the ability to adopt different oxidation states (Mn 2+ , Mn 3+ , Mn 4+ ). Notably, Mn g with a single electron on the e 3+ orbital is the main active site for electrocatalytic water splitting, and its high-spin electronic configuration can produce coordination unsaturation sites, thereby enhancing the adsorption of reactants and optimizing the intermediate binding kinetics, significantly improving the electrocatalytic efficiency of the catalyst. The increase in Mn 3+ concentration is often accompanied by a higher density of oxygen vacancies, which can further improve the catalytic activity of manganese oxides. Needle-shaped α-MnO2 is a tetragonal crystal system with a (2x2) tunnel structure composed of edge-sharing MnO6 octahedra, which provides effective space for electron transfer and rapid transfer of water molecules during electrocatalysis. However, Mn 3+ rich catalysts are hindered in practical applications due to their inherent instability caused by Jahn-Teller distortion, which leads to structural degradation during long-term catalytic cycles. Therefore, stabilizing Mn 3+ while maintaining its catalytic activity is a key challenge in promoting the use of manganese oxides for sustainable energy applications.

[0004] Current studies show that it is an effective way to improve the electrocatalytic activity, selectivity and stability of the catalyst by doping with heteroatoms such as Fe, Co, Ni, Cu, Ru, Ir, etc. to form a solid solution. Doping or intercalation can induce lattice distortion and the formation of oxygen vacancies, stabilize the active sites on the surface of the catalyst and increase the number of active sites, thereby improving the electrocatalytic activity of the catalyst. Chinese patent CN202410570771.8 provides a two-step method for doping manganese oxyhydroxide with metal ruthenium, but the method for constructing heteroatoms or intercalation is complicated and complex, and many steps are required, which limits its application in industrial production.

[0005] Therefore, it is imperative to develop a simple and efficient method for constructing heteroatom-doped manganese oxide. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a metal atom-doped needle-shaped manganese oxide electrocatalyst, a preparation method and application thereof, to solve the problems of instability of active sites in manganese oxides in the prior art and the complicated method for constructing heteroatom-doped manganese oxide. 3+ In view of the deficiencies of the prior art, the purpose of the present application is to provide a metal atom-doped needle-shaped manganese oxide electrocatalyst, a preparation method and application thereof, to solve the problems of instability of active sites in manganese oxides in the prior art and the complicated method for constructing heteroatom-doped manganese oxide.

[0007] The purpose of the present application is to first provide a preparation method of a metal atom-doped needle-shaped manganese oxide electrocatalyst, comprising the following steps:

[0008] S1, pretreatment of carbon paper substrate: cut the carbon paper and sequentially place it in acetone, isopropanol and deionized water for ultrasonic cleaning, and then dry to obtain the pretreated carbon paper;

[0009] S2, preparation of precursor solution: dissolve divalent metal ion compound or trivalent metal ion compound and potassium permanganate (KMnO4) in deionized water and stir, then add HCl and continue to stir to obtain the precursor solution;

[0010] S3, hydrothermal reaction: move the precursor solution obtained in step S2 into a polytetrafluoroethylene-lined high-pressure kettle, vertically place the pretreated carbon paper obtained in step S1, seal, and perform hydrothermal reaction;

[0011] S4, post-treatment: cool, wash and dry the carbon paper after the hydrothermal reaction.

[0012] Preferably, the divalent metal ion includes any one of nickel, cobalt and iron, and the ionic compound includes any one of chloride, nitrate, sulfate and acetate.

[0013] Preferably, the trivalent metal ion includes any one of ruthenium, platinum and aluminum, and the ionic compound includes any one of chloride, nitrate, sulfate and acetate.

[0014] Preferably, in the S1 step, the ultrasonic cleaning time is 8-12 minutes, the drying temperature is 50-80 DEG C, and the drying time is 1-3 hours.

[0015] Preferably, in the S2 step, the molar ratio of the divalent metal ion compound or the trivalent metal ion compound to KMnO4 is 0.01-0.04.

[0016] Preferably, in the S2 step, the concentration of the potassium permanganate solution in deionized water is 0.05-0.1 mol / L, the amount of HCl added is 150-200 muL, the total stirring time is 10-25 minutes, and the stirring rate is 200-800 rpm.

[0017] Preferably, in the S3 step, the hydrothermal reaction temperature is 100-160 DEG C, and the hydrothermal reaction time is 6-18 hours.

[0018] Preferably, in the S4 step, the washing treatment specifically comprises rinsing the surface with deionized water and anhydrous ethanol 2-3 times, and the drying treatment specifically comprises drying at 50-80 DEG C for 12-24 hours.

[0019] The second object of the present application is to provide a metal atom-doped needle-shaped manganese oxide electrocatalyst prepared by the preparation method described above.

[0020] The third object of the present application is to provide an application of a metal atom-doped needle-shaped manganese oxide electrocatalyst, which is applied to hydrogen evolution reaction and oxygen evolution reaction.

[0021] The present application has the following advantages:

[0022] The present application provides a metal atom-doped needle-shaped manganese oxide electrocatalyst and a preparation method. 3+ The present application solves the problems of instability of active sites in manganese oxides prepared by existing methods and complicated methods for constructing heteroatom-doped manganese oxides by directly growing metal atom-doped needle-shaped manganese oxides on a carbon paper substrate by a one-step hydrothermal method.

[0023] In addition, the metal atom doped needle-shaped manganese oxide electrocatalyst is prepared by a one-step method, the preparation method is relatively simple, the types of needle-shaped manganese oxide materials can be expanded, the material adjustability is higher, the inexpensive manganese oxide and divalent / trivalent metal salt materials are used, and the use of noble metals is avoided. Meanwhile, the one-step hydrothermal method only needs a conventional equipment autoclave, the reaction condition is mild (hydrothermal temperature is 100-160 DEG C), and the method is easy to repeat and large-scale applied in an industrial environment. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A step flow chart of the preparation method of the metal atom doped needle-shaped manganese oxide electrocatalyst provided in the embodiments of the present application is shown in the figure.

[0025] Figure 2 A scanning electron microscope image of the Ru atom doped needle-shaped manganese oxide electrocatalyst provided in Embodiment 2 of the present application is shown in the figure.

[0026] Figure 3 A transmission electron microscope image of the Ru atom doped needle-shaped manganese oxide electrocatalyst provided in Embodiment 2 of the present application is shown in the figure.

[0027] Figure 4 An X-ray diffraction pattern of the Ru atom doped needle-shaped manganese oxide electrocatalyst provided in Embodiment 2 of the present application is shown in the figure.

[0028] Figure 5 A linear sweep voltammetry curve of the Ru atom doped needle-shaped manganese oxide electrocatalyst provided in Embodiments 1-4 of the present application in 1M potassium hydroxide solution is shown in the figure.

[0029] Figure 6 A Tafel slope curve of the Ru atom doped needle-shaped manganese oxide electrocatalyst provided in Embodiments 1-4 of the present application in 1M potassium hydroxide solution is shown in the figure.

[0030] Figure 7 A Nyquist impedance plot of the Ru atom doped needle-shaped manganese oxide electrocatalyst provided in Embodiments 1-4 of the present application in 1M potassium hydroxide solution is shown in the figure. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inner", "outer", "inner side", "outer side" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0033] In the description of the present application, several meanings are one or more, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, within, etc. are understood as including the number. If the terms "first", "second", "third" are described, they are only for the purpose of description and for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "setting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. The embodiments will be described below according to the overall structure of the present application.

[0035] Figure 1 The step flow chart of the preparation method of the metal atom doped needle-shaped manganese oxide electrocatalyst provided in the embodiments of the present application is shown in Figure 1 The present application first provides a preparation method of a metal atom doped needle-shaped manganese oxide electrocatalyst, comprising the following steps:

[0036] S1, pretreatment of carbon paper substrate: cut the carbon paper, and sequentially place it in acetone, isopropanol and deionized water for ultrasonic cleaning, and dry to obtain pretreated carbon paper;

[0037] S2, preparation of precursor solution: dissolve divalent metal ion compound or trivalent metal ion compound and KMnO4 in deionized water and stir, then add HCl and continue to stir to obtain the precursor solution;

[0038] S3, hydrothermal reaction: the precursor solution obtained in S2 is moved to a polytetrafluoroethylene-lined autoclave, vertically placed in the pretreated carbon paper obtained in S1, sealed, and subjected to hydrothermal reaction;

[0039] S4, post-treatment: after the hydrothermal reaction, the carbon paper is cooled, washed, and dried.

[0040] In a specific embodiment, the carbon paper is cut into a size of 1*2 cm.

[0041] In a preferred embodiment, the divalent metal ion comprises any one of nickel, cobalt, and iron, and the ionic compound comprises any one of chloride, nitrate, sulfate, and acetate.

[0042] In a preferred embodiment, the trivalent metal ion comprises any one of ruthenium, platinum, and aluminum, and the ionic compound comprises any one of chloride, nitrate, sulfate, and acetate.

[0043] In a preferred embodiment, in S1, the ultrasonic cleaning time is 8-12 minutes, the drying temperature is 50-80℃, and the drying time is 1-3 hours.

[0044] In a preferred embodiment, in S2, the molar ratio of the divalent metal ion compound or the trivalent metal ion compound to KMnO4 is 0.01-0.04.

[0045] In a preferred embodiment, in S2, the concentration of the potassium permanganate solution in deionized water is 0.05-0.1 mol / L, the amount of HCl added is 150-200 μL, the total stirring time is 10-25 minutes, and the stirring rate is 200-800 rpm.

[0046] In a preferred embodiment, in S3, the hydrothermal reaction temperature is 100-160℃, and the hydrothermal reaction time is 6-18 hours.

[0047] In a preferred embodiment, in S4, the washing treatment specifically comprises rinsing the surface with deionized water and anhydrous ethanol for 2-3 times, and the drying treatment specifically comprises drying at 50-80℃ for 12-24 hours.

[0048] The application also provides a metal atom-doped needle-shaped manganese oxide electrocatalyst prepared by the above preparation method.

[0049] The metal atom doped needle-shaped manganese oxide electrocatalyst and the preparation method provided by the application are based on the strategy of lattice distortion induction and oxygen vacancy formation, the metal atom doped needle-shaped manganese oxide is obtained by introducing metal atoms, carbon paper is used as a substrate, and a hydrothermal method is used, the doping of different atoms can stabilize the active sites on the surface of the catalyst and increase the number of the active sites, so that the electrocatalytic activity of the catalyst is improved. In addition, the metal atom doped needle-shaped manganese oxide electrocatalyst is prepared by using a one-step method, the preparation method is relatively simpler, the types of the needle-shaped manganese oxide materials can be expanded, and the adjustability of the materials is higher.

[0050] The application also provides an application of the metal atom doped needle-shaped manganese oxide electrocatalyst.

[0051] Example 1

[0052] Example 1 provides a metal atom doped needle-shaped manganese oxide electrocatalyst and a preparation method thereof, and the specific implementation is as follows:

[0053] The carbon paper is pretreated to remove surface contaminants, specifically, the carbon paper is cut into small pieces of 1*2 cm, and is ultrasonically cleaned in acetone, isopropyl alcohol and deionized water for 10 minutes, respectively, and the cleaned carbon paper is dried in an oven at 60 DEG C for 3 hours, ready for use in the subsequent hydrothermal synthesis process. 0.0042g RuCl3 and 0.2789g KMnO4 are dissolved in 32mL deionized water, stirred for 10 minutes, then 185ul HCl is added to the solution, and stirred for another 15 minutes. The obtained solution is transferred to a 100mL Teflon lined autoclave, the carbon paper is vertically placed in the autoclave, the autoclave is sealed and heated to 120 DEG C, and the reaction is carried out for 12 hours. After the reaction is completed, the autoclave is cooled to room temperature. Then the surface is washed with deionized water and anhydrous ethanol for 2-3 times, respectively, and dried at 60 DEG C for 12 hours. The final sample Ru0.01MnO2 / CP (0.01 is the molar ratio of Ru and Mn) is obtained.

[0054] Example 2

[0055] Example 2 provides a metal atom doped needle-shaped manganese oxide electrocatalyst and a preparation method thereof, and the specific implementation is as follows:

[0056] The carbon paper was pre-treated to remove surface contaminants. Specifically, the carbon paper was cut into 1 x 2 cm pieces and ultrasonically cleaned in acetone, isopropanol and deionized water for 10 minutes each. The cleaned carbon paper was oven dried at 60 °C for 3 hours and ready for use in the subsequent hydrothermal synthesis. 0.0084 g of RuCl3and 0.2789 g of KMnO4were dissolved in 32 mL of deionized water and stirred for 10 minutes. 185 μL of HCl was then added to the solution and stirred for another 15 minutes. The resulting solution was transferred to a 100 mL Teflon lined autoclave and the carbon paper was placed vertically inside the autoclave. The autoclave was sealed and heated to 120 °C for 12 hours. After the reaction was completed, the autoclave was allowed to cool to room temperature. The carbon paper was then rinsed with deionized water and absolute ethanol for 2-3 times each and dried at 60 °C for 12 hours. The final sample Ru0.02MnO2 / CP (0.02 is the molar ratio of Ru to Mn) was obtained.

[0057] Figure 2 Figure 2 is a scanning electron microscope image of the Ru atom doped needle-like manganese oxide electrocatalyst obtained in Example 2, Figure 3 Figure 3 is a transmission electron microscope image of the Ru atom doped needle-like manganese oxide electrocatalyst obtained in Example 2, Figure 4 Figure 4 is an X-ray diffraction pattern of the Ru atom doped needle-like manganese oxide electrocatalyst obtained in Example 2. It shows that the manganese oxide prepared in Example 2 is needle-like and that the Ru atoms are successfully doped.

[0058] Example 3

[0059] Example 3 provides a metal atom doped needle-like manganese oxide electrocatalyst and a method for preparing the same, which is as follows:

[0060] The carbon paper was pre-treated to remove surface contaminants. Specifically, the carbon paper was cut into 1 x 2 cm pieces and ultrasonically cleaned in acetone, isopropanol and deionized water for 10 minutes each. The cleaned carbon paper was oven dried at 60 °C for 3 hours and ready for use in the subsequent hydrothermal synthesis. 0.0084 g of RuCl3and 0.2789 g of KMnO4were dissolved in 32 mL of deionized water and stirred for 10 minutes. 185 μL of HCl was then added to the solution and stirred for another 15 minutes. The resulting solution was transferred to a 100 mL Teflon lined autoclave and the carbon paper was placed vertically inside the autoclave. The autoclave was sealed and heated to 120 °C for 12 hours. After the reaction was completed, the autoclave was allowed to cool to room temperature. The carbon paper was then rinsed with deionized water and absolute ethanol for 2-3 times each and dried at 60 °C for 12 hours. The final sample Ru0.02MnO2 / CP (0.02 is the molar ratio of Ru to Mn) was obtained.

[0061] Example 4

[0062] Example 4 provides a metal atom doped needle-like manganese oxide electrocatalyst and a method for preparing the same, as follows:

[0063] The carbon paper was pretreated to remove surface contaminants. Specifically, the carbon paper was cut into 1 x 2 cm pieces and ultrasonically cleaned in acetone, isopropanol and deionized water for 10 minutes each. The cleaned carbon paper was dried in an oven at 60 °C for 3 hours for later use in the hydrothermal synthesis. 0.0168 g of RuCl3and 0.2789 g of KMnO4were dissolved in 32 mL of deionized water and stirred for 10 minutes. Then, 185 μL of HCl was added to the solution and stirred for another 15 minutes. The resulting solution was transferred to a 100 mL Teflon-lined autoclave, and the carbon paper was placed vertically in the autoclave. The autoclave was sealed and heated to 120 °C for 12 hours. After the reaction, the autoclave was cooled to room temperature. The carbon paper was then rinsed with deionized water and anhydrous ethanol for 2-3 times each and dried at 60 °C for 12 hours. The final sample Ru0.04MnO2 / CP (0.04 is the molar ratio of Ru and Mn) was obtained.

[0064] The Ru atom doped needle-like manganese oxide electrocatalyst samples RuxMnO2 / CP (x is the molar ratio of Ru and Mn, x is 0.01, 0.02, 0.03, 0.04) obtained in Examples 1-4 were tested for hydrogen evolution catalytic activity in 1 M KOH aqueous solution, and the results are shown in Figure 5 From Figure 5 it can be seen that the Ru atom doped needle-like manganese oxide electrocatalyst has low overpotential and excellent catalytic performance, with HER at 10 mA cm -2 overpotential of only 107 mV, which is superior to other metal doped manganese oxide catalysts reported.

[0065] Figure 6 The Tafel slope plots of the Ru atom doped needle-like manganese oxide electrocatalysts obtained in Examples 1-4 show that they have excellent electrochemical kinetics.

[0066] Figure 7 The Nyquist impedance plots of the Ru atom doped needle-like manganese oxide electrocatalysts obtained in Examples 1-4 show that they have low electrochemical impedance.

[0067] In summary, the metal atom doped needle-like manganese oxide electrocatalyst and the method for preparing the same provided by the present application address the problem of Mn 3+The unstable active site, the method for constructing the heteroatom doped manganese oxide is complicated and complex, the metal atom doped needle-like manganese oxide is directly grown on the carbon paper substrate by one-step hydrothermal method. The preparation process only needs to mix the precursor metal ion compound and KMnO4, hydrothermal reaction and post-processing, without multi-step synthesis or complex intercalation. The application induces lattice distortion and oxygen vacancy formation by heteroatom doping (such as Ru, Ni, Co, etc.), stabilizes the active site on the catalyst surface and increases the number of active sites, thereby optimizing the electronic structure and reaction kinetics, and improving the electrocatalytic activity of the catalyst.

[0068] In addition, the application adopts one-step method to prepare metal atom doped needle-like manganese oxide electrocatalyst, the preparation method is relatively simpler, at the same time, the kind of needle-like manganese oxide material can be expanded, the material is more adjustable, the rich and cheap manganese oxide and divalent / trivalent metal salt material is used, and the use of noble metal is avoided. At the same time, one-step hydrothermal method only needs conventional equipment autoclave, the reaction condition is mild (hydrothermal temperature 100-160 DEG C), and it is easy to repeat and large-scale application in industrial environment.

[0069] The above is only the specific embodiment of the application, it should be pointed out that, for those skilled in the technical field, without departing from the principle of the application, a number of improvements and refinements can be made, these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1. A method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst, characterized by, The method comprises the following steps: S1, pretreatment of carbon paper substrate: cut the carbon paper, and sequentially place it in acetone, isopropanol and deionized water for ultrasonic cleaning, and dry to obtain the pretreated carbon paper; S2, preparation of precursor solution: dissolve the divalent metal ion compound or trivalent metal ion compound and potassium permanganate in deionized water and stir, and then add HCl and continue to stir to obtain the precursor solution; S3, hydrothermal reaction: move the precursor solution obtained in step S2 into a polytetrafluoroethylene lined autoclave, vertically place the pretreated carbon paper obtained in step S1, seal, and perform hydrothermal reaction; S4, post-treatment: cool the carbon paper after the hydrothermal reaction, wash, and dry.

2. The method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 1, characterized in that, The divalent metal ion includes any one of nickel, cobalt, and iron, and the ionic compound includes any one of chloride, nitrate, sulfate, and acetate.

3. The method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 1, characterized in that, The trivalent metal ion includes any one of ruthenium, platinum, and aluminum, and the ionic compound includes any one of chloride, nitrate, sulfate, and acetate.

4. The method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 1, characterized in that, In the S1 step, the ultrasonic cleaning time is 8-12 minutes, the drying temperature is 50-80°C, and the drying time is 1-3 hours.

5. The method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 1, characterized in that, In the S2 step, the molar ratio of the divalent metal ion compound or trivalent metal ion compound to potassium permanganate is 0.01-0.

04.

6. The method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 1, characterized in that, In the S2 step, the concentration of the potassium permanganate solution in deionized water is 0.05-0.1 mol / L, the amount of HCl added is 150-200 μL, the total stirring time is 10-25 minutes, and the stirring rate is 200-800 rpm.

7. The method for preparing a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 1, characterized in that, In the S3 step, the hydrothermal reaction temperature is 100-160°C, and the hydrothermal reaction time is 6-18 hours.

8. The method of claim 1, wherein the metal atom-doped needle-shaped manganese oxide electrocatalyst is prepared by the following steps: (1) preparing a manganese oxide precursor; (2) mixing the manganese oxide precursor with a metal atom source to form a mixture; (3) heating the mixture to obtain the metal atom-doped needle-shaped manganese oxide electrocatalyst. In the S4 step, the washing treatment specifically involves rinsing the surface with deionized water and anhydrous ethanol for 2-3 times, and the drying treatment specifically involves drying at 50-80°C for 12-24 hours.

9. A metal atom-doped needle-shaped manganese oxide electrocatalyst, characterized by, The electrocatalyst is prepared by the preparation method of any one of claims 1-8.

10. The use of a metal atom-doped needle-shaped manganese oxide electrocatalyst according to claim 9, characterized in that, The electrocatalyst is applied to hydrogen evolution reaction and oxygen evolution reaction.

Images