CN108565474B - Synthetic method of iron-loaded nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance - Google Patents

Abstract

The invention discloses a synthesis method of an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance. It mixes DMF, pentacyanoammonium ferrite, SBA-15, [VMlm]DCA and sonicates to homogenize, then hydrothermally, adds DMF and transfers it to a flask, then adds 2,2'-azobis, and continues to sonicate, After continuous stirring in the oil bath, the reaction was stopped, dropped into the acetone solution, allowed to stand, suction filtered to obtain the precipitate, dried and ground to obtain a powder product: calcined in a tube furnace to obtain a black powder product; after treatment with dilute hydrofluoric acid The iron-supported nitrogen-doped porous carbon material is obtained; the beneficial effects of the present invention are that, using metallic iron as a metal source, the earth reserves are abundant, the price is low, the material is easy to prepare, and the environmental pollution is small; the electrocatalytic oxygen reduction performance of the obtained material is It has good circulation stability, and methanol has stable anti-toxicity. It has huge economic and social benefits and has a wide application prospect.

Description

An iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance synthetic method

technical field

The invention relates to the field of inorganic nanomaterials and electrochemistry, in particular to a method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance.

Background technique

A fuel cell is a power generation device that directly converts chemical energy stored in fuel and oxidant into electrical energy in an isothermal, efficient and environmentally friendly manner. Due to its high energy conversion efficiency, low pollution, low noise, high continuity and reliability, etc., it has been regarded as the most environmentally friendly and reliable power generation device. However, due to its high cost and immature technology, it is still difficult to industrialize. Cathode oxygen reduction reaction is an important part of fuel cells, and commercial cathode oxygen reduction catalysts mainly use Pt and Pt alloys. However, due to its high price and easy poisoning and inactivation, it is urgent to develop a cheap and reliable alternative.

Transition metal-supported doped porous carbon materials have excellent properties such as low cost, high strength, good stability, environmental protection, strong adsorption capacity, and easy processing, and have the potential to replace commercial platinum carbon. ...) supported heteroatom-doped porous carbon materials have attracted extensive attention due to their abundant earth reserves and excellent properties.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide an iron-supported iron-loaded catalyst with excellent electrocatalytic oxygen reduction performance, which is simple to operate, low in price, high in product yield, and has great economic and practical value. Synthesis of nitrogen-doped porous carbon materials.

The technical scheme of the present invention is as follows:

A method for synthesizing an iron-loaded nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance, characterized in that, pentacyanoammonium ferrite sodium salt and [VMlm]DCA are used as raw materials, and molecular sieve SBA-15 is used as raw material. template, and synthesized according to the quality score ratio. The steps are as follows:

1) Mix 150 parts of pentacyanoammonium ferrite sodium salt, 600 parts of molecular sieve SBA-15, 2000 parts of [VMlm]DCA and 5 parts of anhydrous N,N-dimethylformamide solution (DMF) (feeding ratio 30: 120: 400: 1) Ultrasound is evenly added to the hydrothermal kettle and then heated in water at 80-100°C for 6 hours. Take out the hydrothermal kettle, add 20 parts of anhydrous N,N-dimethylformamide solution to it and transfer it to the flask; take 20 parts of 2,2'-azobis(isobutyronitrile) and dissolve it in 5 parts of anhydrous N,N-dimethylformamide solution, after sonicating uniformly, pour it into a flask; pass nitrogen to the flask for 30-40 minutes, seal it, transfer it to an oil bath at 60-80°C, and stop stirring after 6-10 hours reaction;

The above mixed solution is sealed with nitrogen for 30-40 minutes, transferred to a 60-80 ℃ oil bath, and the reaction is stopped after stirring for 6-10 hours;

2) Drop the solution in step 1) into 200 parts of acetone solution, and after standing, suction filtration to obtain the precipitate, which is then dried in a vacuum drying box. After drying, it is ground into powder for storage.

3) Put the powder in step 2) into a quartz boat, in a tube furnace, under nitrogen atmosphere, heat up to 400-900°C at a heating rate of 5-10°C/min, and maintain the temperature for 1-4 hours , to obtain a black powder product;

4) The black powder product in step 3) is treated with dilute hydrofluoric acid, washed with deionized water, and dried in a vacuum drying oven to obtain an iron-supported nitrogen-doped porous carbon material.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that, in the step 1), the nitrogen gas passage time is 30-40 minutes, and the oil bath temperature is 60-40 minutes. 80°C, stirring time is 6-10 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that, in the step 2), the vacuum drying temperature is 80-100° C., and the drying time is 10-15 Hour.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that, in the step 3), the heating rate of the tube furnace is 6°C/min, and the temperature is 400- 900°C and maintain this temperature for 1-3 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that in the step 3), the heating rate of the tube furnace is 6°C/min, and the temperature is 500°C , and maintain this temperature for 2 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that, in the step 3), the heating rate of the tube furnace is 6°C/min, and the temperature is 600°C , and maintain this temperature for 2 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that, in the step 3), the heating rate of the tube furnace is 6°C/min, and the temperature is 700°C , and maintain this temperature for 2 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that in the step 3), the heating rate of the tube furnace is 6°C/min, and the temperature is 800°C , and maintain this temperature for 2 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that, in the step 3), the heating rate of the tube furnace is 6°C/min, and the temperature is 900°C , and maintain this temperature for 2 hours.

The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that in the step 4), the dilute hydrofluoric acid concentration is 10% wt, and the acid treatment time is 6 hours, the vacuum drying temperature was 80°C, and the time was 12 hours.

The application of the iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance as a fuel cell oxygen reduction catalyst.

The beneficial effects of the invention are that metal iron is used as the metal source, its earth reserves are abundant, and its price is far lower than that of commercial platinum carbon; the material is easy to prepare and has little environmental pollution; the electrocatalytic oxygen reduction performance of the obtained material is better than that of commercial platinum carbon , The half-wave electric potential of 0.836 V (vs RHE) is better than that of platinum carbon 0.81 V (vs RHE), the performance does not decrease significantly after the cycle stability test for 50,000 seconds, and the methanol is stable against toxicity, which has huge economic and social benefits, and has application prospects. very broad.

Description of drawings

Fig. 1 is the scanning electron microscope picture of Fe@NCNTs-800 under 20 micron scale of the present invention;

Fig. 2 is the transmission electron microscope picture of Fe@NCNTs-800 under 10 nanometer scale of the present invention;

Fig. 3 is the transmission electron microscope picture of Fe@NCNT-800 under 5 nanometer scale of the present invention;

Fig. 4 is the scanning curve of the rotating disk electrode of Fe@NCNTs-800 and Pt/C of the present invention under the rotating speed of 1600;

Figure 5 is the scanning curve of the rotating disk electrode (400rpm to 2025rpm) of Fe@NCNTs-800 of the present invention in 0.1M KOH filled with _O2 .

Detailed ways

The technical scheme of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments of the description, but the protection scope of the present invention is not limited thereto:

A method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance, comprising the steps of:

1) Mix 150 parts of pentacyanoammonium ferrite sodium salt, 600 parts of molecular sieve SBA-15, 2000 parts of [VMlm]DCA and 5 parts of anhydrous N,N-dimethylformamide solution (DMF), then ultrasonically uniformly ; Join in the hydrothermal kettle, after 6 hours of water heating at 80-100 ° C, add 20 parts of anhydrous N,N-dimethylformamide solution and transfer to the flask; Take 20 parts of 2,2'-azobis (isobutyronitrile) was dissolved in 5 parts of anhydrous N,N-dimethylformamide solution, and after ultrasonication was uniform, poured into the flask; the flask was passed nitrogen for 30-40 minutes, then sealed, and transferred to 60-80 ℃ oil In the bath, the reaction is stopped after stirring for 6-10 hours;

2) Drop the solution in step 1) into 200 parts of acetone solution, and after standing, suction filtration to obtain the precipitate, which is then dried in a vacuum drying box. After drying, it is ground into powder for storage.

3) Put the powder in step 2) into a quartz boat, in a tube furnace, under nitrogen atmosphere, heat up to 400-900°C at a heating rate of 5-10°C/min, and maintain the temperature for 2-4 hours , to obtain a black powder product;

4) The black powder product in step 3) is treated with dilute hydrofluoric acid, washed with deionized water, and dried in a vacuum drying oven to obtain an iron-supported nitrogen-doped porous carbon material.

The application of the iron-supported nitrogen-doped porous carbon material obtained by the present invention as a fuel cell oxygen reduction catalyst, the performance testing method thereof is as follows:

The prepared iron-supported nitrogen-doped porous carbon material, anhydrous ethanol and Nafion solution were dispersed uniformly by ultrasonic, dropped on the electrode, and then dried in air to form an electrode. The electrode was used as the working electrode, and platinum was used as the working electrode. The sheet electrode was used as the counter electrode, Ag/AgCl was used as the reference electrode, and KOH was used as the electrolyte to assemble a test device for oxygen reduction catalyst to test CV and RDE. The dosage ratio of the porous carbon material and ethanol Nafion solution was 4 mg. : 0.9 mL : 0.1 mL. The electrolyte is a KOH solution with a molar concentration of 0.1 mol/L.

Example 1

Preparation of metallic iron supported nitrogen-doped porous carbon material Fe@NCNTs-800:

Measure 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 150 mg of pentacyanamide ferric sodium salt and 2000 mg of [VMlm]DCA, and after ultrasonication is uniform, the mixture is mixed. Transfer to the liner of the hydrothermal kettle, and after 6 hours of water heating at 80 °C, add 20 mL of N,N-dimethylformamide solution (DMF) and transfer it to a 100 mL flask. Measure another 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 20 mg of 2,2'-azobis(isobutyronitrile), and add it to the above-mentioned flask after sonicating uniformly. After passing nitrogen gas through the above flask for 40 minutes, the flask was sealed and transferred to an oil bath at 70°C. After stirring and heating for 8 hours, the reaction was stopped. After cooling to room temperature, it was dropped into 200 mL of acetone solution and allowed to stand for 2 hours. After that, the product was obtained by suction filtration. The product was dried in a vacuum drying oven at 80°C for 10 hours, and then ground to obtain powder. The above powder was evenly poured into a quartz boat, raised to 800°C at a heating rate of 6°C/min, maintained for 2 hours, and then cooled to room temperature naturally. The calcined product was treated with 10% wt hydrofluoric acid solution for 6 hours, filtered with suction, and washed with deionized water. The obtained product was dried in a vacuum drying oven at 80 °C for 12 hours to obtain the final iron-supported nitrogen-doped porous carbon material Fe@NCNTs-800.

As shown in Figure 1-3, the SEM images of Fe@NCNTs-800 are at 20 microns, 10 microns and 5 microns respectively, and Figure 4 is Fe@NCNTs-800 and Pt/C of the present invention at 1600 rotation speed The scanning curve of the rotating disk electrode; Fig. 5 is the scanning curve of the rotating disk electrode (400rpm to 2025rpm) of Fe@NCNTs-800 of the present invention in 0.1M KOH filled with _O2 ; Nitrogen-doped porous carbon material Fe@NCNTs-800, anhydrous ethanol and Nafion were mixed in a ratio of 4 mg: 0.9 mL: 0.1 mL, and after ultrasonication was uniform, it was dropped on the working electrode, and Ag/AgCl was used as a reference. The specific electrode, KOH as the electrolyte, was assembled into a test device for the oxygen reduction catalyst, and the CV and RDE were tested. The scan rate was 50 mV/s, and the electrolyte was 0.1 M KOH. Its half-wave electric potential of 0.836 V (vs RHE) is better than that of platinum carbon 0.81 V (vs RHE), the performance does not decrease significantly after the cycle stability test for 50,000 seconds, and the methanol has excellent anti-toxicity.

Example 2

Preparation of metallic iron supported nitrogen-doped porous carbon material Fe@NCNTs-400:

Measure 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 150 mg of pentacyanamide ferric sodium salt and 2000 mg of [VMlm]DCA, and after ultrasonication is uniform, transfer the mixture to water In the inner tank of the hot kettle, after 6 hours of water heating at 80 °C, add 20 mL of N,N-dimethylformamide solution (DMF) and transfer it to a 100 mL flask. Take another 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 20 mg of 2,2'-azobis(isobutyronitrile), and add it to the above-mentioned flask after sonicating for uniformity. After passing nitrogen gas through the above flask for 40 minutes, the flask was sealed and transferred to an oil bath at 70°C. After stirring and heating for 8 hours, the reaction was stopped. After cooling to room temperature, it was dropped into 200 mL of acetone solution. After standing, The product was obtained by suction filtration. The product was dried in a vacuum drying oven at 80°C for 10 hours, and then ground to obtain powder. The above powder was evenly poured into a quartz boat, raised to 400°C at a heating rate of 6°C/min, maintained for 2 hours, and then cooled to room temperature naturally. The calcined product was treated with 10% wt hydrofluoric acid solution for 6 hours, filtered with suction, and washed with deionized water. The obtained product was dried in a vacuum drying oven at 80 °C for 12 hours to obtain the final iron-supported nitrogen-doped porous carbon material Fe@NCNTs-400.

The electrocatalytic oxygen reduction reaction performance test conditions are the same as in Example 1, the half-wave electric potential is 0.60 V (vsRHE), the performance does not decrease significantly after the cycle stability test for 50,000 seconds, and the methanol has excellent anti-toxicity.

Example 2

Preparation of metallic iron supported nitrogen-doped porous carbon material Fe@NCNTs-500:

Measure 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 150 mg of pentacyanamide ferric sodium salt and 2000 mg of [VMlm]DCA, and after ultrasonication is uniform, transfer the mixture to water In the inner tank of the hot kettle, after 6 hours of water heating at 80 °C, add 20 mL of N,N-dimethylformamide solution (DMF) and transfer it to a 100 mL flask. Take another 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 20 mg of 2,2'-azobis(isobutyronitrile), and add it to the above-mentioned flask after sonicating for uniformity. After passing nitrogen gas through the above flask for 40 minutes, the flask was sealed and transferred to an oil bath at 70°C. After stirring and heating for 8 hours, the reaction was stopped. After cooling to room temperature, it was dropped into 200 mL of acetone solution. After standing, The product was obtained by suction filtration. The product was dried in a vacuum drying oven at 80°C for 10 hours, and then ground to obtain powder. The above powder was evenly poured into a quartz boat, raised to 500°C at a heating rate of 6°C/min, maintained for 2 hours, and then cooled to room temperature naturally. The calcined product was treated with 10% wt hydrofluoric acid solution for 6 hours, filtered with suction, and washed with deionized water. The obtained product was dried in a vacuum drying oven at 80 °C for 12 hours to obtain the final iron-supported nitrogen-doped porous carbon material Fe@NCNTs-500.

The test conditions of electrocatalytic oxygen reduction reaction performance are the same as those of Example 1. Example 2, the half-wave electric potential is 0.75 V (vs RHE), and the performance does not decrease significantly after the cycle stability test for 50,000 seconds.

Preparation of metallic iron supported nitrogen-doped porous carbon material Fe@NCNTs-600:

Measure 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 150 mg of pentacyanamide ferric sodium salt and 2000 mg of [VMlm]DCA, and after ultrasonication is uniform, transfer the mixture to water In the inner tank of the hot kettle, after 6 hours of water heating at 80 °C, add 20 mL of N,N-dimethylformamide solution (DMF) and transfer it to a 100 mL flask. Take another 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 20 mg of 2,2'-azobis(isobutyronitrile), and add it to the above-mentioned flask after sonicating for uniformity. After passing nitrogen gas through the above flask for 40 minutes, the flask was sealed and transferred to an oil bath at 70°C. After stirring and heating for 8 hours, the reaction was stopped. After cooling to room temperature, it was dropped into 200 mL of acetone solution. After standing, The product was obtained by suction filtration. The product was dried in a vacuum drying oven at 80°C for 10 hours, and then ground to obtain powder. The above powder was evenly poured into a quartz boat, raised to 600°C at a heating rate of 6°C/min, maintained for 2 hours, and then cooled to room temperature naturally. The calcined product was treated with 10% wt hydrofluoric acid solution for 6 hours, filtered with suction, and washed with deionized water. The obtained product was dried in a vacuum drying oven at 80 °C for 12 hours to obtain the final iron-supported nitrogen-doped porous carbon material Fe@NCNTs-600.

The electrocatalytic oxygen reduction reaction performance test conditions are the same as in Example 1, the half-wave electric potential is 0.76 V (vs RHE), the performance does not decrease significantly after the cycle stability test for 50,000 seconds, and the methanol has excellent anti-toxicity.

Example 3

Preparation of metallic iron supported nitrogen-doped porous carbon material Fe@NCNTs-700:

Measure 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 150 mg of pentacyanamide ferric sodium salt and 2000 mg of [VMlm]DCA, and after ultrasonication is uniform, the mixed solution is mixed. Transfer to the liner of the hydrothermal kettle, and after 6 hours of water heating at 80 °C, add 20 mL of N,N-dimethylformamide solution (DMF) and transfer it to a 100 mL flask. Measure another 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 20 mg of 2,2'-azobis(isobutyronitrile), and add it to the above-mentioned flask after sonicating uniformly. After passing nitrogen gas through the above flask for 40 minutes, the flask was sealed and transferred to an oil bath at 70°C. After stirring and heating for 8 hours, the reaction was stopped. After cooling to room temperature, it was dropped into 200 mL of acetone solution. After standing, The product was obtained by suction filtration. The product was dried in a vacuum drying oven at 80°C for 10 hours, and then ground to obtain powder. The above powder was evenly poured into a quartz boat, raised to 700°C at a heating rate of 6°C/min, maintained for 2 hours, and then cooled to room temperature naturally. The calcined product was treated with 10% wt hydrofluoric acid solution for 6 hours, filtered with suction, and washed with deionized water. The obtained product was dried in a vacuum drying oven at 80 °C for 12 hours to obtain the final product Fe@NCNTs-700, an iron-supported nitrogen-doped porous carbon material.

The test conditions of the electrocatalytic oxygen reduction reaction are the same as those of Example 1, the half-wave electric potential is 0.82 V (vs RHE), the performance does not decrease significantly after the cycle stability test for 50,000 seconds, and the methanol has excellent anti-toxicity.

Example 4

Preparation of metallic iron supported nitrogen-doped porous carbon material Fe@NCNTs-900:

Measure 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 150 mg of pentacyanamide ferric sodium salt and 2000 mg of [VMlm]DCA, and after ultrasonication is uniform, the mixed solution is mixed. Transfer to the liner of the hydrothermal kettle, and after 6 hours of water heating at 80 °C, add 20 mL of N,N-dimethylformamide solution (DMF) and transfer it to a 100 mL flask. Measure another 5 mL of N,N-dimethylformamide solution (DMF) into a 50 mL beaker, add 20 mg of 2,2'-azobis(isobutyronitrile), and add it to the above-mentioned flask after sonicating uniformly. After passing nitrogen gas through the above flask for 40 minutes, the flask was sealed and transferred to an oil bath at 70°C. After stirring and heating for 8 hours, the reaction was stopped. After cooling to room temperature, it was dropped into 200 mL of acetone solution. After standing, The product was obtained by suction filtration. The product was dried in a vacuum drying oven at 80°C for 10 hours, and then ground to obtain powder. The above powder was evenly poured into a quartz boat, raised to 900°C at a heating rate of 6°C/min, maintained for 2 hours, and then cooled to room temperature naturally. The calcined product was treated with 10% wt hydrofluoric acid solution for 6 hours, filtered with suction, and washed with deionized water. The obtained product was dried in a vacuum drying oven at 80 °C for 12 hours to obtain the final product Fe@NCNTs-900, an iron-supported nitrogen-doped porous carbon material.

The test conditions of the electrocatalytic oxygen reduction reaction are the same as those of Example 1, the half-wave electric potential is 0.81 V (vs RHE), the performance does not decrease significantly after the cycle stability test for 50,000 seconds, and the methanol has excellent anti-toxicity.

The above descriptions are only part of the embodiments of the present invention and are not intended to limit the present invention; all equivalent changes and modifications made according to the content of the present invention are within the protection scope of the present invention.

Claims (9)

1. A synthetic method of an iron-loaded nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance is characterized in that sodium pentacyano-ammine ferrate and 1-vinyl-3-methylimidazolium dinitrile amine salt [ VMlm ] DCA are used as raw materials, and a molecular sieve SBA-15 is used as a template, and the method is characterized by comprising the following steps:

1) mixing sodium pentacyano-amino ferrate, a molecular sieve SBA-15, [ VMlm ] DCA and an anhydrous N, N-dimethylformamide solution uniformly by ultrasound, adding the mixture into a hydrothermal kettle, maintaining the mixture at 80-100 ℃ for a period of time, taking out the hydrothermal kettle after the completion of the ultrasonic mixing, adding the anhydrous N, N-dimethylformamide solution into the hydrothermal kettle, transferring the solution into a flask, dissolving 2, 2' -azobis (isobutyronitrile) in the anhydrous N, N-dimethylformamide solution uniformly by ultrasound, and pouring the solution into the flask; introducing nitrogen into the flask for 30-40 minutes, sealing, transferring into an oil bath kettle at 60-80 ℃, and stirring for reacting for 6-10 hours to obtain a solution;

2) dripping the solution obtained in the step 1) into an acetone solution, standing, performing suction filtration to obtain a precipitate, drying the precipitate in a vacuum drying oven, grinding the dried precipitate into powder, and storing the powder, wherein the vacuum drying temperature is 80-100 ℃, and the drying time is 10-15 hours;

3) putting the powder in the step 2) into a quartz boat, heating to 400-900 ℃ at a heating rate of 5-10 ℃/min in a tube furnace under a nitrogen atmosphere, and preserving heat for 1-4 hours to obtain a black powder product;

4) treating the black powder product obtained in the step 3) with hydrofluoric acid, washing with deionized water, and drying in a vacuum drying oven to obtain the iron-loaded nitrogen-doped porous carbon material, wherein the concentration of the dilute hydrofluoric acid is 10 wt%, the acid treatment time is 6 hours, the vacuum drying temperature is 80 ℃, and the vacuum drying time is 12 hours.

2. The method for synthesizing an iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties as claimed in claim 1, wherein the nitrogen gas is introduced for 30 to 40 minutes in step 1), the oil bath temperature is 60 to 80 ℃, and the stirring time is 6 to 10 hours.

3. The method for synthesizing an iron-supported nitrogen-doped porous carbon material with excellent electrocatalytic oxygen reduction performance as claimed in claim 1, wherein the temperature rise rate of the tubular furnace in the step 3) is 6 ℃/min, the temperature is 400-.

4. The method for synthesizing an iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties as claimed in claim 1, wherein the temperature rise rate of the tube furnace in the step 3) is 6 ℃/min, the temperature is 500 ℃, and the temperature is maintained for 2 hours.

5. The method for synthesizing an iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties as claimed in claim 1, wherein the temperature rise rate of the tube furnace in the step 3) is 6 ℃/min, the temperature is 600 ℃, and the temperature is maintained for 2 hours.

6. The method for synthesizing an iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties as claimed in claim 1, wherein the temperature rise rate of the tube furnace in the step 3) is 6 ℃/min, the temperature is 700 ℃, and the temperature is maintained for 2 hours.

7. The method for synthesizing an iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties as claimed in claim 1, wherein the temperature rise rate of the tube furnace in the step 3) is 6 ℃/min, the temperature is 800 ℃, and the temperature is maintained for 2 hours.

8. The method for synthesizing an iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties as claimed in claim 1, wherein the temperature rise rate of the tube furnace in the step 3) is 6 ℃/min, the temperature is 900 ℃, and the temperature is maintained for 2 hours.

9. Use of the iron-supported nitrogen-doped porous carbon material having excellent electrocatalytic oxygen reduction properties prepared according to the method of claim 1 as a fuel cell oxygen reduction catalyst.

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