Carbon-coated heterostructure electrocatalyst and preparation and application thereof

Abstract

The present application relates to a kind of carbon-coated heterostructure electrocatalyst and its preparation and application, belong to electrocatalyst technical field.The carbon-coated heterostructure electrocatalyst described in the present application includes nanoparticle with heterostructure and carbon material covering the nanoparticle;The heterostructure is formed by mutual combination of transition metal and its phosphide;The carbon material is nitrogen, phosphorus hetero-element co-doped carbon material.The carbon-coated heterostructure electrocatalyst described in the present application its three-dimensional carbon material base containing a large number of defects has unique structural advantages, including larger specific surface area, high conductivity and good chemical stability, enhance the transfer of electron, effectively promote the activity of water electrolysis hydrogen evolution reaction, the hydrogen evolution reaction activity in full pH range is superior to carbon-supported platinum electrocatalyst.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalysts, and particularly relates to a carbon-coated heterostructure electrocatalyst and a preparation and application thereof. BACKGROUND

[0002] Under the dual pressures of energy crisis and environmental pollution, clean and sustainable energy such as solar energy, wind energy and tidal energy has been developed vigorously, and the commercial development of these new energies needs to convert them into chemical fuels that are easy to store, transport and handle. Among different energy carriers, hydrogen energy has great advantages over other energies due to its high energy density and abundant natural resources, and its final product is only water, so the use of hydrogen energy can greatly reduce the emission of greenhouse gases and harmful gases. The excellent characteristics of hydrogen energy, such as high energy density, zero emission and sustainable recycling, are recognized as one of the ideal energies in the world. In order to meet the development needs of the world's energy demand, it has become a hot spot in the fields of chemistry, materials and energy to develop and develop efficient hydrogen production methods.

[0003] Electrocatalytic water splitting for hydrogen production provides an efficient and clean way. Electrochemical reactions generally occur on the surface of the electrode in the "electrode / solution" interface, so the electrode surface material is an extremely important factor in realizing the electrocatalytic process, and the activity, reaction kinetics and stability also change with the intrinsic properties of the electrode surface and the actual electrochemical conditions. The electrochemical hydrogen evolution reaction is one of the simplest electrochemical reactions, and the reaction steps include adsorption, reduction and desorption processes on the electrode surface. Due to the high overpotential of the hydrogen evolution reaction and the low hydrogen production efficiency, the electrochemical water splitting technology is hindered from being widely used, and in order to overcome these obstacles, it is necessary to introduce active catalysts on the electrode surface, which can significantly reduce the cost of additional energy and improve the conversion efficiency. In the process of hydrogen evolution reaction, hydrogen atoms are adsorbed on the electrode surface catalyst to form hydrogen intermediates, but the formation of hydrogen bonds that is too strong or too weak can lead to a decrease in reaction rate and affect the initial hydrogen adsorption process and the final hydrogen molecule desorption process of the electrode surface catalyst, respectively. If the hydrogen bond formation is too weak, it means that there is no strong interaction between the reactant and the catalyst, and it is difficult for the reactant to complete the process of transforming into the product; if the hydrogen bond formation is too strong, it means that the interaction between the reactant and the catalyst is too strong, which means that the desorption of the product will become extremely difficult. Therefore, the catalyst with neither too strong nor too weak adsorption strength of the reactant is the most efficient catalyst, and in order to improve the hydrogen production efficiency of the electrochemical water splitting hydrogen evolution reaction as much as possible, the development of high-performance electrolytic water hydrogen production catalyst has become one of the real hot spots in the world today.

[0004] It is well known that platinum is the most effective catalyst for hydrogen production by electrolysis of water, which exhibits unique catalytic ability for hydrogen evolution reaction. However, the high price of platinum greatly limits its wide use in commercial and industrial fields. In order to reduce the cost of hydrogen production as much as possible, more inexpensive materials are used and special preparation methods are used to synthesize new catalysts with specific structures, so that they have better water electrolysis hydrogen evolution reaction activity than platinum, and new catalyst synthesis strategies are explored to reduce energy loss and cost in the preparation process as much as possible, so as to facilitate the development of commercial and industrial efficient hydrogen production catalysts. Therefore, it is of great practical significance to further explore and develop low-cost and efficient water electrolysis hydrogen production catalysts to meet the world's future energy demand and national energy strategy development. SUMMARY

[0005] To this end, the technical problem to be solved by the present application is to overcome the problems of high preparation cost and low hydrogen production efficiency of the electrocatalyst in the prior art.

[0006] To solve the above technical problems, the present application provides a carbon-coated heterostructure electrocatalyst and its preparation and application. The electrocatalyst has nanoparticles with a heterostructure embedded in a three-dimensional nitrogen and phosphorus co-doped carbon material containing a large number of defects, forming a porous wrapping layer. The catalyst exhibits excellent activity and stability for water electrolysis hydrogen evolution reaction and hydrazine oxidation reaction in the full pH range, and its water electrolysis hydrogen evolution reaction and hydrazine oxidation reaction performance is better than that of carbon-supported platinum electrocatalyst, and its manufacturing cost is also far lower than that of carbon-supported platinum electrocatalyst, and it has better performance than carbon-supported platinum electrocatalyst.

[0007] The first object of the present application is to provide a carbon-coated heterostructure electrocatalyst, comprising nanoparticles with a heterostructure, and a carbon material coating the nanoparticles; the heterostructure is formed by the mutual combination of transition metals and their phosphides; and the carbon material is a nitrogen and phosphorus hetero-element co-doped carbon material.

[0008] In an embodiment of the present application, the particle size of the nanoparticles is 1-5 nm.

[0009] In an embodiment of the present application, the transition metal is one or more of gold, silver, ruthenium, germanium, palladium, platinum, osmium, iridium, rhodium, platinum and cobalt.

[0010] The second object of the present application is to provide a preparation method of the carbon-coated heterostructure electrocatalyst, comprising the following steps,

[0011] (1) adding a mixed solution to a mixture of transition metal salt, phosphorus source and carbon-nitrogen precursor, and obtaining a powder mixture by ball milling and drying; the mixed solution is obtained by mixing hydrochloric acid solution and ethanol;

[0012] (2) pyrolyzing the powder mixture of step (1) to obtain the carbon-coated heterostructure electrocatalyst; the pyrolysis is divided into two stages, namely a carbon pyrolysis stage and a metal ligand pyrolysis stage.

[0013] In one embodiment of the present application, in step (1), the phosphorus source is one or more of glyphosate, triphenylphosphine, triphenylphosphine oxide, phosphoric acid, phosphorus pentachloride and phosphorus oxychloride.

[0014] In one embodiment of the present application, in step (1), the carbon-nitrogen precursor is one or more of melamine, urea, dicyandiamide, monocyandiamide and aniline.

[0015] In one embodiment of the present application, in step (1), the transition metal salt is a chloride salt and / or an acetate salt.

[0016] In one embodiment of the present application, in step (1), the mass ratio of the transition metal salt, the phosphorus source and the carbon-nitrogen precursor is 1:30-80:300-450.

[0017] Preferably, in step (1), the mass ratio of the transition metal salt, the phosphorus source and the carbon-nitrogen precursor is 1:50-70:320-360.

[0018] In one embodiment of the present application, in step (1), the volume ratio of the hydrochloric acid solution and the ethanol in the mixed solution is 1:3-10.

[0019] In one embodiment of the present application, in step (1), the volume concentration of the hydrochloric acid solution is 30-44%.

[0020] In one embodiment of the present application, in step (2), the carbon pyrolysis stage is to raise the temperature to 500-700℃ at a rate of 1-5℃ / min, and to keep the temperature for 60-180min.

[0021] In one embodiment of the present application, in step (2), the metal ligand pyrolysis stage is to raise the temperature to 700-900℃ at a rate of 1-5℃ / min, and to keep the temperature for 30-180min.

[0022] A third object of the present application is to provide an application of the carbon-coated heterostructure electrocatalyst in electrolytic water hydrogen evolution reaction and hydrazine oxidation reaction.

[0023] The technical solution of the present application has the following advantages compared with the prior art:

[0024] (1) The carbon-coated heterostructure electrocatalyst has nanoparticles with a heterostructure embedded in three-dimensional nitrogen and phosphorus co-doped carbon material containing a large number of defects, forming a porous wrapping layer, and the three-dimensional carbon material substrate containing a large number of defects has a unique structural advantage, so that the material has a large specific surface area, and a large number of voids inside, which is beneficial to the transfer of electrons and protons and the adsorption and desorption capacity of gas, thereby enhancing the hydrogen production rate and efficiency of the water electrolysis hydrogen evolution reaction, and has good corrosion resistance.

[0025] (2) The carbon-coated heterostructure electrocatalyst has nanoparticles uniformly distributed, and the particle density is extremely high, so there are a large number of active sites, which enhances the efficiency of the water electrolysis hydrogen evolution reaction.

[0026] (3) The carbon-coated heterostructure electrocatalyst has nanoparticles with a unique heterojunction structure that effectively adjusts the electronic structure of the catalyst surface, optimizes the adsorption / desorption effect of reaction intermediates in the reaction process, thereby improving the rate of the water electrolysis hydrogen evolution reaction and the hydrazine oxidation reaction, so that its activity in the hydrogen evolution reaction in the full pH range and the hydrazine oxidation reaction under alkaline conditions is better than that of the commercial carbon-supported platinum electrocatalyst.

[0027] (4) The preparation method of the carbon-coated heterostructure electrocatalyst adopts a ball milling method to fully mix and mill the precursor uniformly, and then performs high-temperature pyrolysis, so that the overall synthesis method is simple and easy to prepare, and can be mass-produced. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings, in which:

[0029] Figure 1 The SEM image of the carbon-supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application.

[0030] Figure 2 The bright-field TEM image of the carbon-supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application.

[0031] Figure 3 The characterization image of the carbon-supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application; the upper left is a dark-field TEM image, the lower left is an EDS full spectrum image, and the rest are EDS images of the marked elements.

[0032] Figure 4 The XRD image of the carbon-supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application.

[0033] Figure 5BET graph of the carbon supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application.

[0034] Figure 6 Hydrogen evolution reaction electrochemical polarization curve graph of the carbon supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application and 20% carbon supported platinum electrocatalyst.

[0035] Figure 7 Hydrogen evolution reaction electrochemical polarization curve graph of the carbon supported rhodium / diphosphine rhodium heterostructure electrocatalyst of Example 1 of the present application and 20% carbon supported platinum electrocatalyst. DETAILED DESCRIPTION

[0036] The present application will be further described below in conjunction with the accompanying drawings and specific examples so that those skilled in the art can better understand and implement the present application, but the examples are not intended to limit the present application.

[0037] In the present application, unless otherwise specified, the volume concentration of concentrated hydrochloric acid is 34%.

[0038] Example 1

[0039] A carbon-coated heterostructure electrocatalyst and its preparation, specifically comprising the following steps:

[0040] (1) Accurately weigh 25 mg of rhodium chloride and 1.4 g of glyphosate and 8 g of melamine, mix them together and grind for 5 min, and then put them into an oven for full drying.

[0041] (2) Put the fully dried powder mixture into a ball mill tank, use a planetary ball mill to treat for 1.5 h, then add 15 mL of a mixed solution of concentrated hydrochloric acid and ethanol (1:4), use the ball mill to treat for 10 min again, and finally put it into an oven for full drying.

[0042] (3) Put the fully dried mixture into a ball mill and ball mill for 30 min, grind the mixture into powder, put it into a sealed quartz boat, and then transfer the quartz boat into a tube furnace, first heat to 650℃ at a rate of 2.5℃ / min in an inert atmosphere, and keep the temperature for 2 h; then increase to 850℃ at a rate of 2℃ / min, and keep the temperature for 1.5 h, to obtain a carbon supported rhodium / diphosphine rhodium heterostructure electrocatalyst.

[0043] Example 2

[0044] A carbon-coated heterostructure electrocatalyst and its preparation, specifically comprising the following steps:

[0045] (1) Accurately weigh 20 mg of rhodium chloride and 1.6 g of glyphosate and 8.5 g of melamine, mix them together and grind for 5 min, and then put them into an oven for full drying.

[0046] (2) The powder mixture after sufficient drying treatment is put into a ball mill tank, and a planetary ball mill is used for ball milling treatment for 1.5 h, then 15 mL of a mixed solution of concentrated hydrochloric acid and ethanol (1:4) is added, and the ball mill is used for ball milling treatment for 10 min, and finally it is put into an oven for sufficient drying.

[0047] (3) The mixture after sufficient drying is put into a ball mill for ball milling for 30 min, and the mixture is ground into powder and put into a sealed quartz boat, and then the quartz boat is transferred into a tube-type calcination furnace, and heated to 650℃ at a rate of 2.5℃ / min in an inert atmosphere, and kept for 2 h; then added to 850℃ at a rate of 2℃ / min, and kept for 1.5 h, to obtain a carbon-coated rhodium / rhodium diphosphide heterostructure electrocatalyst.

[0048] Example 3

[0049] A carbon-coated heterostructure electrocatalyst and a preparation method thereof, specifically comprising the following steps:

[0050] (1) 30 mg of rhodium chloride and 1.5 g of glyphosate and 9 g of melamine are accurately weighed and mixed together, ground for 5 min, and then put into an oven for sufficient drying.

[0051] (2) The powder mixture after sufficient drying treatment is put into a ball mill tank, and a planetary ball mill is used for ball milling treatment for 1.5 h, then 15 mL of a mixed solution of concentrated hydrochloric acid and ethanol (1:4) is added, and the ball mill is used for ball milling treatment for 10 min, and finally it is put into an oven for sufficient drying.

[0052] (3) The mixture after sufficient drying is put into a ball mill for ball milling for 30 min, and the mixture is ground into powder and put into a sealed quartz boat, and then the quartz boat is transferred into a tube-type calcination furnace, and heated to 650℃ at a rate of 2.5℃ / min in an inert atmosphere, and kept for 2 h; then added to 850℃ at a rate of 2℃ / min, and kept for 1.5 h, to obtain a carbon-coated rhodium / rhodium diphosphide heterostructure electrocatalyst.

[0053] Example 4

[0054] A carbon-coated heterostructure electrocatalyst and a preparation method thereof, specifically comprising the following steps:

[0055] (1) 30 mg of rhodium chloride and 1.5 g of glyphosate and 9 g of melamine are accurately weighed and mixed together, ground for 5 min, and then put into an oven for sufficient drying.

[0056] (2) The powder mixture after sufficient drying treatment is put into a ball mill tank, and a planetary ball mill is used for ball milling treatment for 1.5 h, then 20 mL of a mixed solution of concentrated hydrochloric acid and ethanol (1:6) is added, and the ball mill is used for ball milling treatment for 10 min, and finally it is put into an oven for sufficient drying.

[0057] (3) The mixture after sufficient drying is put into a ball mill for ball milling for 30 min, and the mixture is ground into powder and put into a sealed quartz boat, and then the quartz boat is transferred into a tube calciner, and heated to 650℃ at a rate of 2.5℃ / min in an inert atmosphere, and kept for 2 h; then heated to 900℃ at a rate of 2℃ / min, and kept for 1 h, to obtain a carbon-coated ruthenium / ruthenium diphosphide heterostructure electrocatalyst.

[0058] Example 5

[0059] A carbon-coated heterostructure electrocatalyst and a preparation method thereof, specifically comprising the following steps:

[0060] (1) 30 mg of iridium chloride, 1.5 g of glyphosate, and 9 g of melamine are accurately weighed and mixed together, and then ground for 5 min, and then put into an oven for sufficient drying.

[0061] (2) The powder mixture after sufficient drying treatment is put into a ball mill tank, and a planetary ball mill is used for ball milling treatment for 1.5 h, then 20 mL of a mixed solution of concentrated hydrochloric acid and ethanol (1:6) is added, and the ball mill is used for ball milling treatment for 10 min, and finally it is put into an oven for sufficient drying.

[0062] (3) The mixture after sufficient drying is put into a ball mill for ball milling for 30 min, and the mixture is ground into powder and put into a sealed quartz boat, and then the quartz boat is transferred into a tube calciner, and heated to 650℃ at a rate of 2.5℃ / min in an inert atmosphere, and kept for 2 h; then heated to 900℃ at a rate of 2℃ / min, and kept for 1 h, to obtain a carbon-coated iridium / ruthenium diphosphide heterostructure electrocatalyst.

[0063] Example 6

[0064] A carbon-coated heterostructure electrocatalyst and a preparation method thereof, specifically comprising the following steps:

[0065] (1) 30 mg of iridium chloride, 1.5 g of glyphosate, and 9 g of melamine are accurately weighed and mixed together, and then ground for 5 min, and then put into an oven for sufficient drying.

[0066] (2) The powder mixture after sufficient drying treatment is put into a ball mill tank, and a planetary ball mill is used for ball milling treatment for 1.5 h, then 20 mL of a mixed solution of concentrated hydrochloric acid and ethanol (1:6) is added, and the ball mill is used for ball milling treatment for 10 min, and finally it is put into an oven for sufficient drying.

[0067] (3) The mixture after sufficient drying was put into a ball mill and ball-milled for 30 min. After the mixture was ground into powder, it was put into a sealed quartz boat, and then the quartz boat was transferred into a tube furnace. The temperature was raised to 650°C at a rate of 2.5°C / min in an inert atmosphere, and then the temperature was kept for 2 h. Then the temperature was raised to 900°C at a rate of 2°C / min, and then the temperature was kept for 1 h to obtain the carbon-supported cobalt / biphosphide cobalt heterogeneous structure electrocatalyst.

[0068] Test Example 1

[0069] (1) Scanning Electron Microscope (SEM)

[0070] The carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst prepared in Example 1 was subjected to scanning electron microscope (SEM) characterization, and the results are shown in FIG. 1, which shows that the three-dimensional graphene substrate contains a large number of pore defects. Figure 1 Figure 1

[0071] (2) Transmission Electron Microscope (TEM)

[0072] The carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst prepared in Example 1 was subjected to transmission electron microscope (TEM) characterization, and the results are shown in FIG. 2, which shows that the average size of the nanoparticles formed by the carbon-supported rhodium / biphosphide rhodium heterogeneous structure in the carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst is about 2.59 nm. Figure 2 Figure 2

[0073] (3) EDS-Mapping

[0074] The carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst prepared in Example 1 was subjected to EDS-Mapping analysis, and the results are shown in FIG. 3, which shows that the main elements in the carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst are carbon, nitrogen, phosphorus, and rhodium elements, which are uniformly dispersed. Figure 3 Figure 3

[0075] (4) X-ray Diffraction (XRD)

[0076] The carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst prepared in Example 1 was subjected to X-ray diffraction (XRD) analysis, and the results are shown in FIG. 4, which clearly shows the characteristic diffraction peaks belonging to rhodium and the characteristic diffraction peaks belonging to biphosphide rhodium. Figure 4 Figure 4

[0077] (5) Specific Surface Area

[0078] The carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst prepared in Example 1 was subjected to specific surface area test (BET), and the results are shown in FIG. 5, which shows that the specific surface area of the carbon-supported rhodium / biphosphide rhodium heterogeneous structure electrocatalyst is about 1.23 m2 / g. Figure 5 Figure 5 ​​​​​​​​​It can be seen that the specific surface area of ​​the carbon-supported rhodium / rhodium diphosphide heterostructure electrocatalyst is 913.38 cm -2 .

[0079] Test Example 2

[0080] (1) Hydrogen evolution reaction by water electrolysis

[0081] The carbon-supported rhodium / rhodium diphosphide heterostructure electrocatalyst prepared in Example 1 and the 20% carbon-supported platinum electrocatalyst were tested for hydrogen evolution reaction in water electrolysis, specifically comprising the following steps:

[0082] 5 mg of sample was mixed with 0.49 mL of isopropanol, 0.49 mL of deionized water, and 0.02 mL of Nafion solution (5 wt.%, CAS NO. 31175-20-9), and then ultrasonicated for 2 hours to mix evenly. 6 microliters of the prepared mixed solution was then dropped onto a glassy carbon electrode (5 mm in diameter) and dried naturally to obtain a working electrode. After the material was prepared into a working electrode, the electrolysis of water and hydrogen evolution reaction were carried out in 0.5 M H2SO4 (a), 0.5 M PBS (b), and 0.1 M KOH (c) at room temperature, respectively. The linear sweep voltammetry graphs are shown in FIG. Figure 6 As shown by Figure 6 It can be seen that under the three environmental conditions, the activity of carbon-supported rhodium / rhodium diphosphide heterostructure electrocatalyst in the electrolysis of water and hydrogen evolution reaction is better than that of carbon-supported platinum catalyst.

[0083] (2) Hydrazine oxidation reaction

[0084] The carbon-supported rhodium / rhodium diphosphide heterostructure electrocatalyst prepared in Example 1 and the 20% carbon-supported platinum electrocatalyst were subjected to a hydrazine oxidation reaction test, specifically comprising the following steps:

[0085] After the material was prepared into a working electrode, hydrazine oxidation reaction was carried out in a mixed solution of 1M KOH and 0.1M hydrazine at the optimal working temperature. The linear sweep voltammetry diagram is shown in FIG. Figure 7 As shown by Figure 7 It can be seen that under these environmental conditions, the hydrazine oxidation reaction activity of the carbon-supported rhodium / rhodium diphosphide heterostructure electrocatalyst is better than that of the carbon-supported platinum electrocatalyst, which indicates that the carbon-supported rhodium / rhodium diphosphide heterostructure electrocatalyst is also an extremely active bifunctional catalyst.

[0086] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A carbon-coated heterostructure electrocatalyst, characterized in that: The invention relates to nanoparticles having a heterogeneous structure and a carbon material coating the nanoparticles; the heterogeneous structure is formed by combining a transition metal and its phosphide; the carbon material is a carbon material co-doped with nitrogen and phosphorus heterogeneous elements; the transition metal is one or more of gold, silver, ruthenium, palladium, platinum, osmium, iridium, rhodium and cobalt; and the particle size of the nanoparticles is 1-5 nm. The preparation method of the carbon-coated heterostructure electrocatalyst, The following steps are included: (1) adding a mixed solution to a mixture of a transition metal salt, a phosphorus source, and a carbon-nitrogen precursor, ball milling, and drying to obtain a powder mixture; the mixed solution is obtained by mixing a hydrochloric acid solution and ethanol; The mass ratio of the transition metal salt, the phosphorus source and the carbon-nitrogen precursor is 1:30-80:300-450; (2) Pyrolyzing the powder mixture described in step (1) to obtain the carbon-coated heterostructure electrocatalyst; the pyrolysis is divided into two stages, namely, a carbon pyrolysis stage and a metal ligand pyrolysis stage.

2. The carbon-coated heterostructure electrocatalyst according to claim 1, characterized in that: In step (1), the phosphorus source is one or more of glyphosate, triphenylphosphine, triphenylphosphine oxide, phosphoric acid, phosphorus pentachloride and phosphorus oxychloride; and the carbon-nitrogen precursor is one or more of melamine, urea, dicyandiamide, monocyanamide and aniline.

3. The carbon-coated heterostructure electrocatalyst according to claim 1, characterized in that: In step (1), the volume ratio of hydrochloric acid solution to ethanol in the mixed solution is 1:3-10.

4. The carbon-coated heterostructure electrocatalyst according to claim 1, characterized in that: In step (2), the carbon pyrolysis stage is to increase the temperature to 500-700°C at a rate of 1-5°C / min and keep the temperature for 60-180 minutes.

5. The carbon-coated heterostructure electrocatalyst according to claim 1, characterized in that: In step (2), the metal ligand thermal decomposition stage is to increase the temperature to 700-900°C at a rate of 1-5°C / min and keep the temperature for 30-180 minutes.

6. Use of the carbon-coated heterostructure electrocatalyst according to any one of claims 1 to 5 in hydrogen evolution reaction by water electrolysis and hydrazine oxidation reaction.

Images