Nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst and preparation method thereof

Abstract

This invention relates to a nitrogen-doped graphene oxide sheet-supported NiFe oxygen evolution electrocatalyst and its preparation method. The preparation method includes: adding graphene oxide that has been ultrasonically dispersed for 30-100 min to a methylimidazole solution, stirring continuously, adding 1-5 g of nitrogen-doped precursor, stirring at room temperature, and then adding a mixed solution containing nickel transition metal salt, iron transition metal salt and aluminum transition metal salt, stirring to obtain a mixed solution; filtering the mixed solution under low pressure, drying, and grinding the dried block with an agate mortar to obtain a brownish-yellow powder; pouring the powder into a porcelain boat, passing an inert gas and / or reducing gas through a tube furnace, heating to 300-600℃, calcining for 0.5-5 hours, then heating to 700-1000℃, calcining for 0.5-4 hours, and cooling to room temperature to obtain a black powder; hot washing the black powder in an excess alkaline solution at 60-100℃ for 5-20 hours, then filtering the mixed liquid under low pressure and washing with deionized water until neutral to obtain a nitrogen-doped graphene oxide sheet-supported NiFe oxygen evolution electrocatalyst.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrocatalysis, and in particular to a nitrogen-doped graphene oxide sheet loaded NiFeAl oxygen evolution electrocatalyst and a preparation method. BACKGROUND

[0002] The technology of electrolyzing water using renewable energy has broad prospects, because no fossil fuel is used in the process of electrolysis to produce hydrogen, and the produced hydrogen is a green and sustainable energy. The oxygen evolution reaction (OER) is a half-reaction of water electrolysis, and the kinetics is slower than that of the other half-reaction, i.e. the hydrogen evolution reaction (HER), and the energy consumption is also higher. In order to promote the reaction efficiency while keeping low energy consumption, the OER needs a more efficient catalyst. At present, noble metal-based oxides such as RuO2 and IrO2 have a low overpotential and can exhibit high OER catalytic activity, but they are rare in the earth's crust and have a high market price, which seriously hinders the commercial application of water electrolysis. Therefore, it is of great significance to develop a cheap, high-activity and stable non-noble transition metal-based electrocatalyst to catalyze the OER in the alkaline water electrolysis reaction.

[0003] In this regard, alloys based on the abundant Ni and Fe transition metal elements in the earth's crust as OER active catalysts have attracted great attention. In 1987, Corrigan's team reported that a small amount of Fe (0.01%) in the electrolyte solution significantly affected the OER performance of the Ni electrode. The Tafel slopes of the nickel electrodes with and without iron were 70 mV dec -1 and 20-25 mV dec -1 , respectively, indicating that the incorporation of Fe greatly improved the OER activity. However, the NiFe-based electrocatalyst has a small number of active sites, low conversion rate and insufficient electrical conductivity, which leads to a lack of activity and stability. SUMMARY

[0004] The purpose of the present application is to solve the problems of insufficient OER catalytic activity, too small specific surface area and poor catalytic durability of the traditional NiFe-based carbon-based composite material, and a nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst and a preparation method are provided.

[0005] To this end, in a first aspect, the present application provides a preparation method of a nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst, and the preparation method comprises the following steps:

[0006] Preferably, the nitrogen-doped precursor includes one or more of melamine, ammonia, polypyrrole, or polyaniline.

[0007] The mixed solution is filtered under low pressure at -0.1-0.09 MPa, and the obtained filter cake is vacuum dried at 40-100°C for 10-40 hours. The dried block is ground with an agate mortar for 10-40 min to obtain a brownish yellow powder.

[0008] The powder is poured into a porcelain boat and evenly laid flat. The porcelain boat is placed in a tube furnace, inert gas and / or reducing gas are introduced into the tube furnace, the temperature is raised to 300-600°C at a rate of 2-8°C / min, calcined for 0.5-5 hours, then the temperature is raised to 700-1000°C at a rate of 2-8°C / min, calcined for 0.5-4 hours, and cooled to room temperature to obtain a black powder.

[0009] The black powder is washed in an excess of alkaline solution at 60-100°C for 5-20 hours, and then the mixed liquid is filtered under low pressure and washed with deionized water until neutral to obtain a nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst.

[0010] Preferably, the nitrogen-doped precursor includes one or more of melamine, ammonia, polypyrrole, or polyaniline.

[0011] Preferably, the nickel transition metal salt includes one or more of Ni(NO3)2·6H2O, NiCl2·6H2O, Ni(CH3COO)2·6H2O, and Ni SO4·6H2O.

[0012] The iron transition metal salt includes one or more of Fe(NO3)3·6H2O, FeCl3·6H2O, Fe(CH3COO)3, and Fe2(SO4)3·6H2O.

[0013] The aluminum transition metal salt includes one or more of Al(NO3)3·9H2O, Al Cl3·6H2O, Al(OH)(C2H3O2)2, and Al2(SO4)3·16H2O.

[0014] Preferably, the molar ratio of the nickel transition metal salt, the iron transition metal salt and the substance with aluminum transition metal salt is 0.1-5:0.1-5:0.1-5.

[0015] Preferably, the porcelain boat is specifically corundum round-bottom porcelain boat.

[0016] Preferably, the inert gas includes N2 and / or Ar; and the reducing gas includes H2.

[0017] Preferably, the alkali solution includes one or more of KOH, NaOH and NH3H2O; the alkali solution has a dosage of 50-200 mL and a concentration of 0.5-5 mol / L.

[0018] In the second aspect, the present application provides a nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst prepared by the preparation method of the first aspect.

[0019] Preferably, the oxygen evolution electrocatalyst includes a structural unit and a conductive network embedded in the structural unit.

[0020] The structural unit is composed of nitrogen-doped graphene oxide (NGO), and the conductive network is composed of nickel-iron alloy nanoparticles and pores; wherein Al is used to generate the pores, thereby increasing the specific surface area of the material and increasing the exposure of NiFe active sites.

[0021] Preferably, the nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst is used for alkaline electrocatalytic oxygen evolution reaction.

[0022] The present application provides a preparation method of nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst. The method uses nitrogen-doped graphene oxide as a substrate, and by doping metal Al in the NiFe alloy, the Al is removed after the material is synthesized and pores are generated in the alloy nanoparticles. The method improves the conductivity of the NiFe alloy through the nitrogen-doped graphene oxide substrate, and is beneficial to the penetration of the electrolyte and the rapid discharge of oxygen. The pores generated by Al can further increase the specific surface area of the material, fully expose the NiFe active sites, and accelerate mass transfer. The present application uses an in-situ synthesis method with water solvent stirring to prepare a porous NiFe-based OER catalyst with strong catalytic performance and persistent catalytic activity. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The present application provides a preparation method of nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst.

[0024] Figure 2A lower micrograph of a scanning electron microscope (SEM) of the nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst prepared for the present embodiment 1;

[0025] Figure 3 A linear sweep voltammetry characteristic curve test graph (LSV) of the oxygen evolution reaction (OER) of the present embodiment 1 and the comparative examples 1, 2, 3, 4 in 0.1 mol / L KOH solution. DETAILED DESCRIPTION

[0026] The technical solutions of the present application are further described in detail below through the drawings and embodiments.

[0027] The present embodiment provides a nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst, and the main steps of the preparation method are as shown in the figure Figure 1 , including:

[0028] Step 110: 1-10 mmol of 2-methyl imidazole is dissolved in 10-50 mL of deionized water at room temperature to form a methyl imidazole solution, and then 30-100 min of ultrasonic dispersion of graphene oxide (GO) is added in the methyl imidazole solution, and the stirring is continued for 1-20 hours; Then add 1-5 g of nitrogen-doped precursor, stir at room temperature for 1-20 hours; Then add a mixed solution containing 0.1-5 mmol of nickel transition metal salt, 0.1-5 mmol of iron transition metal salt and 0.1-5 mmol of aluminum transition metal salt, and continue to stir for 5-40 hours to obtain a mixed solution;

[0029] Among them, the nitrogen-doped precursor includes one or more of melamine, ammonia, polypyrrole or polyaniline.

[0030] The nickel transition metal salt includes one or more of Ni(NO3)2·6H2O, Ni Cl2·6H2O, Ni(CHCO3)2·6H2O, Ni SO4·6H2O.

[0031] The iron transition metal salt includes one or more of Fe(NO3)3·6H2O, FeCl3·6H2O, Fe(CH3COO)3, Fe2(SO4)3·6H2O.

[0032] The aluminum transition metal salt includes one or more of Al(NO3)3·9H2O, Al Cl3·6H2O, Al(OH)(C2H3O2)2, Al2(SO4)3·16H2O.

[0033] The mass ratio of the above nickel transition metal salt, iron transition metal salt and aluminum transition metal salt is 0.1-5:0.1-5:0.1-5.

[0034] Step 120, the mixed solution is filtered under low pressure of -0.1-0.09 MPa, the filter cake is dried under vacuum at 40-100℃ for 10-40 hours, and the dried block is ground with a corundum mortar for 10-40 min to obtain a brownish yellow powder;

[0035] Step 130, the powder is poured into a porcelain boat and evenly laid, the porcelain boat is placed in a tube furnace, inert gas and / or reducing gas is introduced into the tube furnace, the temperature is raised to 300-600℃ at a rate of 2-8℃ / min, calcined for 0.5-5 hours, then the temperature is raised to 700-1000℃ at a rate of 2-8℃ / min, calcined for 0.5-4 hours, and a black powder is obtained after cooling to room temperature;

[0036] The porcelain boat can preferably be a corundum round-bottom porcelain boat.

[0037] The inert gas includes N2 and / or Ar; the reducing gas includes H2. Therefore, it can also be a mixture of N2 and H2 or a mixture of Ar and H2.

[0038] Step 140, the black powder is washed at 60-100℃ for 5-20 hours in an excess of an alkaline solution, then the mixed liquid is filtered under low pressure and washed with deionized water until neutral to obtain a nitrogen-doped graphene oxide sheet loaded NiFeAl oxygen evolution electrocatalyst.

[0039] The alkaline solution includes one or more of KOH, NaOH and NH3·H2O; the amount of the alkaline solution is 50-200 mL, and the concentration is 0.5-5 mol / L.

[0040] The Al in the black powder is removed by the alkaline solution, so that the Al metal nanoparticles originally formed by high-temperature sintering are etched, the particle positions are left with voids, and finally the material has a pore structure.

[0041] In order to better illustrate the technical solutions of the present application, the following specific examples and comparative examples are used to further illustrate the present application, but it should be understood that these examples are only used for more detailed illustration, and should not be understood as limiting the present application in any form, i.e. not intended to limit the protection scope of the present application.

[0042] Example 1

[0043] This example provides a synthesis of a nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst:

[0044] The 5 mmol 2-methylimidazole was dissolved in 30 mL deionized water at room temperature, then graphene oxide (GO) dispersed by ultrasonic for 100 min was added into the methyl imidazole solution, and stirred for 10 hours. Then 4 g of melamine was added, and stirred at room temperature for 12 hours. Then a mixed solution containing 2 mmol Ni(NO3)2·6H2O, 2 mmol Fe(NO3)3·6H2O and 6 mmol Al(NO3)3·9H2O was added, and stirred for 20 hours. The uniformly mixed solution was low-pressure suction filtered, and the obtained filter cake was vacuum dried at 80°C for 12 hours. The dried block was ground with an agate mortar for 30 min to obtain a brownish yellow powder. The powder was poured into a corundum round-bottom porcelain boat and evenly spread, and the porcelain boat was placed in a tube furnace, and the tube furnace was connected with an inert gas or a reducing gas. The temperature program was set to increase the temperature to 380°C at a rate of 5°C / min, calcine for 3 hours, then increase the temperature to 900°C at a rate of 3°C / min, calcine for 2 hours, and then cool to room temperature to obtain a black powder sample. The powder sample was washed in an excess of alkali solution at 80°C for 8 hours. After completion, the mixed liquid was low-pressure suction filtered and washed with deionized water until neutral to obtain a sample of nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst.

[0045] The morphology of the nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst material obtained in Example 1 was analyzed by scanning electron microscopy (SEM), and the results are shown in FIG. 1. Figure 2 As shown in FIG. 1, the graphene oxide substrate of the material can be seen, and the metal nanoparticles are embedded in the nitrogen-doped graphene oxide.

[0046] Comparative Example 1

[0047] This comparative example provides a synthesis of a nitrogen-doped graphene oxide sheet loaded Ni material (Ni@NGO).

[0048] The 5 mmol 2-methylimidazole was dissolved in 30 mL deionized water at room temperature, then graphene oxide (GO) dispersed by ultrasonic for 100 min was added into the methyl imidazole solution, and stirred for 10 hours. Then 4 g of melamine was added, and stirred at room temperature for 12 hours. Then a solution containing 2 mmol Ni(NO3)2·6H2O was added, and stirred for 20 hours. The uniformly mixed solution was low-pressure suction filtered, and the obtained filter cake was vacuum dried at 80°C for 12 hours. The dried block was ground with an agate mortar for 30 min to obtain a brownish yellow powder. The powder was poured into a corundum round-bottom porcelain boat and evenly spread, and the porcelain boat was placed in a tube furnace, and the tube furnace was connected with an inert gas or a reducing gas. The temperature program was set to increase the temperature to 380°C at a rate of 5°C / min, calcine for 3 hours, then increase the temperature to 900°C at a rate of 3°C / min, calcine for 2 hours, and then cool to room temperature to obtain a black powder sample Ni@NGO.

[0049] Comparative Example 2

[0050] This comparative example provides a synthesis of a nitrogen-doped graphene oxide sheet supported Fe material (Fe@NGO).

[0051] 5 mmol 2-methylimidazole was dissolved in 30 mL deionized water at room temperature, then graphene oxide (GO) was added into the methylimidazole solution and ultrasonically dispersed for 100 min, and stirring was continued for 10 hours. Then 4 g of melamine was added, and stirring was continued at room temperature for 12 hours. Then a solution containing 2 mmol Fe(N03)3-6H20 was added, and stirring was continued for 20 hours. The uniformly mixed solution was filtered under low pressure, and the obtained filter cake was vacuum dried at 80°C for 12 hours. The dried block was ground with an agate mortar for 30 min to obtain a brownish yellow powder. The powder was poured into a corundum round-bottom porcelain boat and evenly spread, and the porcelain boat was placed in a tube furnace, which was purged with an inert gas or a reducing gas. The temperature program was set to increase the temperature to 380°C at a rate of 5°C / min, calcine for 3 hours, then increase the temperature to 900°C at a rate of 3°C / min, calcine for 2 hours, and then cool to room temperature to obtain a black powder sample Fe@NGO.

[0052] Comparative Example 3

[0053] This comparative example provides a synthesis of a nitrogen-doped graphene oxide sheet supported NiFe material (NiFe@NGO).

[0054] 5 mmol 2-methylimidazole was dissolved in 30 mL deionized water at room temperature, then graphene oxide (GO) was added into the methylimidazole solution and ultrasonically dispersed for 100 min, and stirring was continued for 10 hours. Then 4 g of melamine was added, and stirring was continued at room temperature for 12 hours. Then a solution containing 2 mmol Ni(N03)2-6H20 and 2 mmol Fe(N03)3-6H20 was added, and stirring was continued for 20 hours. The uniformly mixed solution was filtered under low pressure, and the obtained filter cake was vacuum dried at 80°C for 12 hours. The dried block was ground with an agate mortar for 30 min to obtain a brownish yellow powder. The powder was poured into a corundum round-bottom porcelain boat and evenly spread, and the porcelain boat was placed in a tube furnace, which was purged with an inert gas or a reducing gas. The temperature program was set to increase the temperature to 380°C at a rate of 5°C / min, calcine for 3 hours, then increase the temperature to 900°C at a rate of 3°C / min, calcine for 2 hours, and then cool to room temperature to obtain a black powder sample NiFe@NGO.

[0055] Comparative Example 4

[0056] This comparative example provides a synthesis of a nitrogen-doped graphene oxide sheet material (NGO).

[0057] 5 mmol 2-methylimidazole was dissolved in 30 mL deionized water at room temperature, then graphene oxide (GO) was added into the methylimidazole solution and ultrasonically dispersed for 100 min, and stirred for 10 h. Then 4 g of melamine was added, and stirred at room temperature for 12 h. The uniformly mixed solution was low-pressure suction filtered, and the obtained filter cake was vacuum dried at 80 °C for 12 h. The dried block was ground with an agate mortar for 30 min to obtain a brownish yellow powder. The powder was poured into a corundum round-bottom porcelain boat and evenly spread, and the porcelain boat was placed in a tube furnace, and the tube furnace was purged with an inert gas or a reducing gas. The temperature program was set to increase the temperature to 380 °C at a rate of 5 °C / min, and calcined for 3 h, then increased to 900 °C at a rate of 3 °C / min, and calcined for 2 h, and then cooled to room temperature to obtain a black powder sample NGO.

[0058] The bifunctional catalytic performance of the above examples and comparative examples was evaluated, and all the electrochemical tests used an electrochemical workstation model CHI 760E equipped with a PINE rotating disc electrode test system, and the electrochemical tests were all carried out at room temperature.

[0059] Preparation of working electrode: using a rotating disc electrode (RDE), i.e. a glassy carbon electrode (GCE, d = 5 mm), the electrode surface was first polished to a mirror surface using Al2O3 powder on a polishing cloth, then rinsed several times with deionized water, and dried at room temperature before use. 4 mg of the NiFe@NGO material obtained in Example 1, 261 μL of isopropanol, 652 μL of deionized water, and 87 μL of a Nafion solution (5 wt%) were accurately weighed and mixed, and the mixture was ultrasonically treated for 1 h. Finally, 10 μL of the above prepared slurry was uniformly dropped on the surface of the GCE, and naturally dried to obtain the working electrode used for testing. The loading of the catalyst on the electrode surface was 0.20 mg / cm 2 .

[0060] As a control experiment, a commercial RuO2 catalyst was also prepared using the same working electrode preparation method, and was used as Comparative Example 5 for electrochemical performance testing.

[0061] Electrochemical performance test: a standard three-electrode electrochemical test system was used during the test, in which the counter electrode was a Pt sheet, the reference electrode was a saturated calomel electrode (SCE), and the working electrode was prepared as described above.

[0062] The OER performance of the sample obtained in Example 1 in 0.1 mol / L KOH solution was tested using a rotating disc electrode (RDE), and the LSV curve at a rotation speed of 1600 rpm is shown in Figure 3 The sample of Example 1 showed high OER electrocatalytic activity, and when the current density reached 10 mA / cm 2At this time, the overpotential in the alkaline medium was 360 mV. The overpotential of Comparative Example 1 was 465 mV, the overpotential of Comparative Example 2 was 438 mV, the overpotential of Comparative Example 3 was 397 mV, the overpotential of Comparative Example 4 was 669 mV, and the overpotential of Comparative Example 5 was 411 mV. Compared with Example and Comparative Example 3, Comparative Examples 1 and 2 used single metals Ni and Fe, respectively. By comparing the oxygen evolution overpotentials of the three, it can be concluded that the activity of the Example using the double metal NiFe is better than that of Comparative Examples 1 and 2. Compared with the Example, Comparative Example 3 only introduced the double metal Ni and Fe, but did not use the method of etching the Al metal with alkali to manufacture pores, expand the active area, and enhance the catalytic activity. It can be concluded from the oxygen evolution overpotentials of the two that the Example using the method of etching the Al metal with alkali to manufacture pores has more excellent catalytic activity. Comparative Example 4 does not introduce metal, and the purpose of comparison with the Example is to prove that the performance of the substrate graphene is improved after the introduction of metal. Comparative Example 5 is a commercial oxygen evolution reaction active catalyst, and the purpose of comparison with the Example is to prove that the product prepared by the application has a catalytic activity better than that of the commercial material.

[0063] The preparation method of the nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst provided by the embodiment of the application. The method uses nitrogen-doped graphene oxide as a substrate, introduces metal Al into the NiFe alloy, removes Al after the synthesis of the material, and manufactures pores in the alloy nanoparticles. The method improves the conductivity of the NiFe alloy through the nitrogen-doped graphene oxide substrate, facilitates the penetration of the electrolyte and the rapid discharge of oxygen, eliminates the pores generated by Al, further increases the specific surface area of the material, fully exposes the NiFe active sites, and accelerates mass transfer. The application uses an in-situ synthesis method of stirring in an aqueous solvent to prepare a porous NiFe-based OER catalyst with strong catalytic performance and persistent catalytic activity.

[0064] The above specific embodiments further illustrate the purpose, technical solutions, and beneficial effects of the application. It should be understood that the above description is only a specific embodiment of the application and is not used to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A method for preparing a nitrogen-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst, characterized in that, The preparation method comprises: 1-10 mmol of 2-methylimidazole is dissolved in 10-50 mL of deionized water to form a methylimidazole solution at room temperature, and then graphene oxide after ultrasonic dispersion for 30-100 min is added into the methylimidazole solution, and stirring is continued for 1-20 hours; then 1-5 g of a nitrogen-doped precursor is added, and stirring is continued at room temperature for 1-20 hours; then a mixed solution containing 0.1-5 mmol of a nickel transition metal salt, 0.1-5 mmol of an iron transition metal salt and 0.1-5 mmol of an aluminum transition metal salt is added, and stirring is continued for 5-40 hours to obtain a mixed solution; The mixed solution is filtered under low pressure at -0.1~0.09 MPa, and the obtained filter cake is vacuum dried at 40-100℃ for 10-40 hours, and the dried block is ground with a jade mortar for 10-40 min to obtain a brownish yellow powder; The powder is poured into a porcelain boat and evenly laid, and the porcelain boat is placed in a tube furnace, inert gas and / or reducing gas are introduced into the tube furnace, the temperature is raised to 300-600℃ at a rate of 2-8℃ / min, calcination is performed for 0.5-5 hours, then the temperature is raised to 700-1000℃ at a rate of 2-8℃ / min, calcination is performed for 0.5-4 hours, and a black powder is obtained after cooling to room temperature; The black powder is washed in an excess of an alkaline solution at 60-100℃ for 5-20 hours to remove the aluminum component in the black powder, then the mixed solution is filtered under low pressure and washed with deionized water until neutral to obtain a nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst with a porous hole structure.

2. The production method according to claim 1, characterized by, The nitrogen-doped precursor comprises one or more of melamine, ammonia, polypyrrole or polyaniline.

3. The preparation method according to claim 1, characterized in that, The nickel transition metal salt comprises one or more of Ni(NO3)2·6H2O, NiCl2·6H2O, Ni(CHCO3)2·6H2O and NiSO4·6H2O; The iron transition metal salt comprises one or more of Fe(NO3)3·6H2O, FeCl3·6H2O, Fe(CH3COO)3 and Fe2(SO4)3·6H2O; The aluminum transition metal salt comprises one or more of Al(NO3)3·9H2O, AlCl3·6H2O, Al(OH)(C2H3O2)2 and Al2(SO4)3·16H2O.

4. The production method according to claim 1, characterized by, The molar ratio of the nickel transition metal salt, the iron transition metal salt and the aluminum transition metal salt is 0.1-5:0.1-5:0.1-5.

5. The preparation method according to claim 1, characterized in that, The porcelain boat is specifically a corundum round-bottom porcelain boat.

6. The method of claim 1, wherein, The inert gas comprises N2 and / or Ar, and the reducing gas comprises H2.

7. The preparation method according to claim 1, characterized in that, The alkaline solution comprises one or more of KOH, NaOH and NH3·H2O, and the amount of the alkaline solution is 50-200 mL, and the concentration is 0.5-5 mol / L.

8. A nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst prepared by the preparation method of any one of claims 1-7.

9. The N-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst of claim 8, wherein, The oxygen evolution electrocatalyst comprises structural units and a conductive network inlaid in the structural units; The structural units are composed of nitrogen-doped graphene oxide, and the conductive network is composed of nickel-iron alloy nanoparticles and pores; wherein the pores are formed after removal of an aluminum transition metal salt by alkaline washing, so as to increase the specific surface area of the material and increase the exposure of NiFe active sites.

10. The N-doped graphene oxide sheet supported NiFe oxygen evolution electrocatalyst of claim 8, wherein, The nitrogen-doped graphene oxide sheet loaded NiFe oxygen evolution electrocatalyst is used for alkaline electrocatalytic oxygen evolution reaction.

Images