CN113839058A

CN113839058A - Carbon-based oxygen reduction reaction catalyst and preparation method thereof

Info

Publication number: CN113839058A
Application number: CN202111116725.3A
Authority: CN
Inventors: 欧子豪; 郭朝中; 覃媛; 徐川岚; 刘建平; 许欣如; 刘瑶; 高洁; 姜莹
Original assignee: Chongqing University of Arts and Sciences
Current assignee: Chongqing University of Arts and Sciences
Priority date: 2021-09-23
Filing date: 2021-09-23
Publication date: 2021-12-24
Anticipated expiration: 2041-09-23
Also published as: CN113839058B

Abstract

The invention discloses a carbon-based oxygen reduction reaction catalyst and a preparation method thereof, wherein the preparation method comprises the following steps: 1) carrying out pre-carbonization treatment on the waste cosmetic cotton, and then carrying out acid pickling, water washing and drying to obtain a pyrolytic polymer; 2) adding zinc salt and ammonium fluoride into a pyrolytic polymer according to the mass ratio of the pyrolytic polymer to the zinc salt to the ammonium fluoride of 1 (0.2-4) to (0.1-2), adding a solvent, grinding uniformly, and drying to obtain a precursor; 3) putting the precursor into a tubular furnace, heating the precursor from room temperature to 800-1000 ℃ at the heating rate of 5-15 ℃/min for heat treatment for 1-3h under the inert atmosphere, then naturally cooling the precursor to room temperature, taking out the precursor for acid washing, water washing and drying, continuously putting the precursor into the tubular furnace, heating the precursor from room temperature to 800-1000 ℃ at the heating rate of 5-15 ℃/min for heat treatment for 1-3h under the inert atmosphere, and taking out the precursor after the heat treatment is finished and naturally cooling the precursor to room temperature to obtain the catalyst. The carbon-based oxygen reduction reaction catalyst prepared by the method has high activity, good stability and outstanding battery performance.

Description

Carbon-based oxygen reduction reaction catalyst and preparation method thereof

Technical Field

The invention relates to an oxygen reduction reaction catalyst under a fuel cell cathode, in particular to a carbon-based oxygen reduction reaction catalyst and a preparation method thereof.

Background

Due to the energy crisis and environmental pollution caused by the continuous consumption of traditional fossil fuels, advanced and clean new energy technology is widely concerned by academia. However, the Oxygen Reduction Reaction (ORR) at the cathode during the discharge process has been greatly limiting the development of advanced energy conversion systems such as fuel cells and Metal Air Batteries (MABs) due to its slow reaction kinetics and diverse reaction pathways. Currently, platinum-based catalysts are the most effective commercial ORR catalysts. But its price is high, stability is poor, easy to be poisoned, etc., so it has limited its wide application in fuel cell. Therefore, developing a non-noble metal catalyst with high efficiency, low cost, stability to replace the platinum-based noble metal catalyst is a significant challenge in today's world.

In recent years, a carbon-based metal-free catalyst is favored by the scientific research community due to the characteristics of low cost, good conductivity, high stability and the like, and the oxygen reduction catalytic effect of the catalyst is obviously improved after the elements such as N, P, S, F and the like are introduced; in addition, designing and synthesizing a structure with layered porosity and ultrahigh specific surface area is another important method for improving catalytic activity. At present, however, the synthesis process of most catalysts is too complicated, so that the large-scale production of the catalysts is difficult; in addition, it is very difficult to maintain the layered porous active structure with ultra-high specific surface area while doping efficiently.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the carbon-based oxygen reduction reaction catalyst which is low in cost, simple in process steps, large in specific surface area and high in activity and takes waste cosmetic cotton as a carbon source, and the preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a carbon-based oxygen reduction reaction catalyst comprises the following steps:

1) carrying out pre-carbonization treatment on the waste cosmetic cotton, and then carrying out acid pickling, water washing and drying to obtain a pyrolytic polymer;

2) adding zinc salt and ammonium fluoride into a pyrolytic polymer according to the mass ratio of the pyrolytic polymer to the zinc salt to the ammonium fluoride of 1 (0.2-4) to (0.1-2), adding a solvent, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor into a tubular furnace, heating the precursor from room temperature to 800-1000 ℃ at the heating rate of 5-15 ℃/min for heat treatment for 1-3h under the inert atmosphere, then naturally cooling the precursor to room temperature, taking out the precursor for acid washing, water washing and drying, continuously putting the precursor into the tubular furnace, heating the precursor from room temperature to 800-1000 ℃ at the heating rate of 5-15 ℃/min for heat treatment for 1-3h under the inert atmosphere, and taking out the precursor after the heat treatment is finished and naturally cooling the precursor to room temperature to obtain the catalyst.

Further, the temperature of the pre-carbonization treatment in the step 1) is 200-.

Further, the zinc salt in the step 2) is one or a combination of any several of zinc chloride, zinc sulfate and zinc nitrate.

Further, the solvent in the step 2) is methanol or ethanol.

Further, the acid washing condition in the step 1) and the step 3) is that the acid is magnetically stirred for 6 to 10 hours in 0.4 to 0.6M sulfuric acid at the temperature of between 70 and 85 ℃.

The invention also provides a carbon-based oxygen reduction reaction catalyst which is an N, F co-doped porous carbon-based structure and has a specific surface area of more than 2000m².g^-1。

Compared with the prior art, the invention has the following technical effects:

1. the waste cosmetic cotton is used as a raw material, so that the waste is utilized, and the cost is saved.

2. The preparation process of the catalyst is simple and convenient, and is easy for large-scale industrial production.

3. The catalyst prepared by the method has rich pore structures, and the structure can increase the diffusion rate of electrolyte, accelerate oxygen transmission and enable the catalyst to have higher reaction activity; and the zinc salt and ammonium fluoride can expose more N, F doping sites as a dual activator, so that the electrocatalytic performance of the catalyst is remarkably improved, and the power density and the energy density of the catalyst can be higher than those of a commercial Pt/C catalyst when the catalyst is assembled into a battery.

Drawings

FIG. 1 is a transmission electron micrograph of a CF-Zn-F catalyst prepared in example 1 of the present invention;

FIG. 2 is a nitrogen adsorption-desorption isotherm plot of the CF-Zn-F catalyst prepared in example 1 of the present invention, with the inset being the corresponding BJH pore size distribution plot;

FIG. 3 is an XRD scan of the CF-Zn-F catalyst prepared in example 1 of the present invention;

FIG. 4 is a Raman plot of the CF-Zn-F, CF-Zn and CF-F catalysts prepared in example 1, comparative example 2 and comparative example 3 of the present invention;

FIG. 5 shows the results of the reactions of the CF-Zn-F, CF-Zn and CF-F catalysts prepared in example 1, comparative example 2 and comparative example 3 of the present invention in O₂And N₂CV curve in saturated 0.1M KOH solution.

FIG. 6 is an LSV curve of the CF-Zn-F, CF-Zn and CF-F catalysts prepared in example 1, comparative example 2 and comparative example 3 of the present invention versus a commercial Pt/C catalyst;

FIG. 7 is a statistical graph of the average hydrogen peroxide yields and average number of transferred electrons for the CF-Zn-F, CF-Zn, and CF-F catalysts prepared in example 1, comparative example 2, and comparative example 3 according to the present invention and the commercial Pt/C catalyst;

FIG. 8 is a LSV graph of catalysts prepared at different heat treatment temperatures according to the present invention in example 1, comparative example 4, comparative example 5 and comparative example 6;

FIG. 9 is a LSV plot of CF-Zn-F and commercial Pt/C catalysts prepared in example 1 of the present invention after 0 and 5000 passes of the scan;

FIG. 10 is a graph showing the methanol poisoning resistance curves of CF-Zn-F and a commercial Pt/C catalyst prepared in example 1 of the present invention;

FIG. 11 is a graph of discharge polarization curves and corresponding power densities for a zinc-air cell with CF-Zn-F and a commercial Pt/C catalyst, respectively, as air electrodes, prepared in example 1 of the present invention;

FIG. 12 is a graph showing the energy density of a zinc-air battery in which CF-Zn-F prepared in example 1 of the present invention and a commercial Pt/C catalyst are used as air electrodes, respectively.

Detailed Description

The present invention will be explained in further detail with reference to examples.

The invention provides a preparation method of a carbon-based oxygen reduction reaction catalyst, which specifically comprises the following steps:

1) carrying out pre-carbonization treatment on the waste cosmetic cotton to remove internal grease to form a standard carbon material, then cleaning the carbon material by acid washing, washing for multiple times to remove residual acid, and drying to obtain a pyrolytic polymer;

2) adding zinc salt and ammonium fluoride into a pyrolytic polymer according to the mass ratio of the pyrolytic polymer to the zinc salt to the ammonium fluoride of 1 (0.2-4) to (0.1-2), adding a solvent, grinding uniformly, and drying to obtain a precursor, wherein the solvent is added only for fully grinding, and no special requirement is imposed on the amount of the solvent;

3) putting the precursor into a tubular furnace, heating the precursor from room temperature to 800-1000 ℃ at the heating rate of 5-15 ℃/min for heat treatment for 1-3h in an inert atmosphere to form N, F co-doped porous carbon-based structure, naturally cooling the porous carbon-based structure to the room temperature, taking out the material, removing unstable metal agglomerated substances in the material by acid washing, washing the material for multiple times to remove residual acid, drying the material, continuously putting the material into the tubular furnace, heating the material from the room temperature to 800-1000 ℃ at the heating rate of 5-15 ℃/min for heat treatment for 1-3h in the inert atmosphere to form more stable N, F co-doped porous carbon-based structure, and taking out the catalyst after the heat treatment is finished and naturally cooled to the room temperature.

The invention also relates to a carbon-based oxygen reduction reaction catalyst prepared by the method, wherein the catalyst is an N, F co-doped porous carbon-based structure, and the specific surface area of the catalyst is more than 2000m².g^-1。

The drying referred to above has no special requirements on temperature, but generally does not exceed 100 ℃.

To further explain the technical solution of the present invention in detail, the following description will be given with reference to specific examples.

Example 1

The embodiment provides a preparation method of a carbon-based oxygen reduction reaction catalyst, which specifically comprises the following steps:

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 1h at 350 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.5M sulfuric acid, carrying out magnetic stirring for 8h in a water bath at 80 ℃, washing for many times to remove residual sulfuric acid, filtering, and drying in an oven at 60 ℃ to obtain a pyrolytic polymer;

2) adding 0.24g of zinc chloride and 0.03g of ammonium fluoride into the 0.12g of pyrolytic polymer obtained in the step 1), mixing, adding ethanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, removing unstable metal agglomerated substances in the material, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ oven, putting the precursor into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF-Zn-F.

FIG. 1 is a Transmission Electron Microscope (TEM) image of the CF-Zn-F catalyst prepared in this example; from the TEM image, the catalyst is composed of a disordered carbon structure and contains a rich pore structure, and the structure can increase the diffusion rate of an electrolyte, accelerate oxygen transmission and enable the catalyst to have better performance.

FIG. 2 is a nitrogen adsorption-desorption isotherm plot of the CF-Zn-F catalyst prepared in this example, with the corresponding BJH pore size distribution as the inset; it can be seen from the figure that the catalyst is at a relatively low N₂Pressure (P/P)₀<0.1) shows a steep increase at higher N₂Pressure (P/P)₀>0.4) shows a clear hysteresis loop reflecting a typical type I isotherm of the coexistence of micropores and mesopores, and the specific surface area of the catalyst was measured to be 2251m².g^-1Wherein the micropore area fraction is calculated to be up to 90.8%. This ultra-high BET specific surface area is attributed to the activation of zinc chloride, which is introduced into the carbon material, creating a large number of pores after pyrolysis and etching, and the rich microporous structure facilitates increased mass transfer capacity, ultimately improving electrocatalytic performance.

FIG. 3 is an XRD scan of the CF-Zn-F catalyst prepared in this example; two peaks at approximately 23 ° and 44 ° were observed in the XRD pattern of the prepared catalyst, which are (002) and (101) planes of carbon, respectively, indicating that no zinc or zinc oxide particles were formed.

Comparative example 1

A preparation method of a carbon-based oxygen reduction reaction catalyst specifically comprises the following steps:

2) taking 0.12g of the pyrolysis polymer in the step 1), adding ethanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then placing the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ drying oven, then putting into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF.

Comparative example 2

2) taking 0.12g of the pyrolysis polymer in the step 1) and 0.24g of zinc chloride, adding ethanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, removing unstable metal agglomerated substances in the material, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ oven, putting the precursor into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF-Zn.

Comparative example 3

2) taking 0.12g of the pyrolysis polymer and 0.03g of ammonium fluoride in the step 1), adding ethanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then placing the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ oven, then putting into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF-F.

Comparative example 4

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 800 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, removing unstable metal agglomerated substances in the material, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ oven, putting the precursor into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 800 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF-Zn-F-800.

Comparative example 5

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 900 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, removing unstable metal agglomerated substances in the material, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ oven, putting the precursor into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 900 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF-Zn-F-900.

Comparative example 6

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 1000 ℃ at the heating rate of 10 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.5M sulfuric acid, magnetically stirring for 8h in 80 ℃ water bath, removing unstable metal agglomerated substances in the material, washing for many times to remove residual sulfuric acid, filtering, drying in a 60 ℃ oven, putting the precursor into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 1000 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst which is marked as CF-Zn-F-1000.

To illustrate the technical effects of the present invention in detail, the following electrochemical catalytic oxygen reduction reaction performance tests were performed on CF-Zn-F, CF-Zn, CF-F, CF-Zn-F-800, CF-Zn-F-900 and CF-Zn-F-1000 prepared in example 1 and comparative example 1, comparative example 2, comparative example 3, comparative example 4, comparative example 5 and comparative example 6, respectively; the catalyst CF-Zn-F obtained in example 1 was assembled into a zinc air fuel cell, tested for cell performance, and compared to a commercial 20% Pt/C catalyst.

All electrochemical data were tested using an electrochemical workstation of CHI760E (shanghai chenhua instruments ltd., china), using a three-electrode system with a rotating ring-disk as the working electrode (RRDE, Pine, usa), a saturated mercury oxide electrode (Hg/HgO) as the reference electrode, and a graphite rod as the counter electrode. All electrode potentials were switched to the potential of the Reversible Hydrogen Electrode (RHE). The cyclic voltammetric sweep (CV) measurement is at O₂And N₂Saturated 0.1M KOH solution at a scan rate of 50mV/s, whereas Linear voltammetric scanning (LSV) was performed at a rotation rate of 400 and 2500rpm, at a scan rate of 10 mV/s. The primary metal zinc-air battery comprises the following components: the metal zinc plate is used as an anode, the carbon paper loaded with the catalyst is used as an air cathode, the foamed nickel is used as a current collector, and the electrolyte of 6M KOH is added.

The following detailed analysis is performed in conjunction with FIGS. 4-10.

FIG. 4 shows Raman spectra of CF-Zn-F, CF-Zn and CF-F catalysts prepared in example 1, comparative example 2 and comparative example 3 of the present invention; it can be seen from the figure that CF and CF-Zn have the same I_D/I_GIt is shown that activation with zinc chloride alone does not significantly affect the degree of graphitization of the catalyst; and CF-Zn-F has the smallest I_D/I_GDemonstrating its highest degree of graphitization and excellent conductivity, it was demonstrated that zinc chloride and ammonium fluoride as dual activators can expose more N, F doping sites, thereby increasing the degree of graphitization.

FIG. 5 shows the respective O contents of the CF-Zn-F, CF-Zn and CF-F catalysts prepared in example 1, comparative example 2 and comparative example 3 according to the present invention₂And N₂Cyclic voltammetric scan curves in saturated 0.1M KOH solution; as is clear from the figure, CF-Zn-F (0.78V) has more positive oxygen reduction peak potential than CF (0.62V), CF-Zn (0.69V) and CF-F (0.68V) (vs. RHE), indicating that the prepared CF-Zn-F catalyst has higher reactivity.

FIG. 6 shows linear voltammograms of the CF-Zn-F, CF-Zn and CF-F catalysts prepared according to the present invention in example 1, comparative example 2 and comparative example 3 versus a commercial Pt/C catalyst; CF-Zn-F (0.83V, 6.27 mA/cm) in oxygen-saturated 0.1M KOH at 1600rpm²) Half-wave potential of (2) with commercial Pt/C (0.85V, 5.80 mA/cm)²) Comparable, but stronger limiting current densities. Furthermore, it is specific to CF (0.68V, 3.25 mA/cm)²)、CF-Zn(0.73V，3.91mA/cm²) And CF-F (0.72V, 4.46 mA/cm)²) Much higher. These results indicate that activation of zinc chloride and doping of heteroatoms can significantly improve the electrocatalytic properties of CF, while the high ORR activity of CF-Zn-F benefits from the dual activation effect.

FIG. 7 is a statistical graph of the average hydrogen peroxide yields and average number of transferred electrons for the CF-Zn-F, CF-Zn, and CF-F catalysts prepared in example 1, comparative example 2, and comparative example 3 according to the present invention and the commercial Pt/C catalyst; as can be seen from the graph, the average H of CF-Zn-F₂O₂The yield is 5.8%, which is far lowerCompared with CF (3.02), CF-Zn (3.28) and CF-F (3.74), the CF-Zn-F has an average electron number of transmission of 3.88, which is equivalent to that of a Pt/C catalyst, and is far higher than that of CF (3.9), CF-Zn (35.8%) and CF-F (12.7%), which shows that the CF-Zn-F has a near four-electron reaction path and has high selectivity for oxygen reduction of water.

Fig. 8 shows linear voltammetry scan curves for catalysts prepared according to the present invention in example 1, comparative example 4, comparative example 5, and comparative example 6 at different heat treatment temperatures. In 0.1M KOH saturated with oxygen, at 1600rpm, CF-Zn-F-950 has higher half-wave potential and limiting current density than CF-Zn-F-800, CF-Zn-F-900 and CF-Zn-F-1000, indicating that temperature can promote the generation of more active sites, but too high temperature can decompose the active sites, therefore, the result indicates that the catalytic effect is best when heat treatment is carried out at 950 ℃.

FIG. 9, FIG. 10, shows the long cycle stability and methanol poisoning resistance of the CF-Zn-F catalyst and Pt/C catalyst prepared in example 1 of the present invention. As can be seen from FIG. 9, the half-wave potential of the Pt/C catalyst decayed by 22mV after 5000 CV cycles, while the CF-Zn-F decayed by only 12mV, indicating that the synthesized CF-Zn-F catalyst has good stability; as can be seen from FIG. 10, the current density of CF-Zn-F shows negligible decay, reflecting its excellent methanol resistance, compared to the sharp drop in current density after Pt/C injection of 3M methanol at 400 and 700 seconds.

Fig. 11 and 12 show the discharge polarization curve and the corresponding power density and energy density plots of the zinc-air battery using the CF-Zn-F catalyst and the Pt/C catalyst prepared in example 1 of the present invention as air electrodes, respectively. The maximum power density of the battery assembled by using CF-Zn-F at the air cathode is 220.3mW/cm²Much higher than Pt/C (136.5 mW/cm)²) Meanwhile, the zinc-air battery based on the CF-Zn-F electrocatalyst is at 50mA/cm²When providing

Specific capacity of (2), this ratio being Pt/C

Slightly lower, and corresponding energy density of

Greatly exceeds Pt/C

The performance of the primary zinc-air battery shows that the CF-Zn-F electrocatalyst has considerable application potential in an advanced energy conversion system.

In order to fully illustrate the technical scheme of the invention, the invention also provides the following specific embodiments:

example 2

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 1h at 250 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.6M sulfuric acid, carrying out magnetic stirring for 6h in a 70 ℃ water bath, washing with water for multiple times, filtering, and drying in a 70 ℃ oven to obtain a pyrolytic polymer;

2) adding 0.024g of zinc sulfate and 0.012g of ammonium fluoride into the pyrolytic polymer (0.12g) obtained in the step 1), mixing, adding ethanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing argon gas for protection in the whole process, heating to 800 ℃ at the heating rate of 10 ℃/min for heat treatment for 3h, naturally cooling to room temperature after the heat treatment is finished, then placing the precursor into 0.6M sulfuric acid, magnetically stirring for 6h in 70 ℃ water bath, washing with water for multiple times, filtering, drying in a 70 ℃ oven, putting into the tubular furnace again, introducing argon gas for protection in the whole process, heating to 1000 ℃ at the heating rate of 15 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst.

Example 3

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 2h at 200 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.55M sulfuric acid, carrying out magnetic stirring for 9h in a water bath at 85 ℃, washing for multiple times, filtering, and drying in an oven at 55 ℃ to obtain a pyrolytic polymer;

2) adding 0.024g of zinc sulfate and 0.24g of ammonium fluoride into the pyrolytic polymer (0.12g) obtained in the step 1), mixing, adding methanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 800 ℃ at the heating rate of 5 ℃/min for heat treatment for 3h, naturally cooling to room temperature after the heat treatment is finished, then placing the precursor into 0.55M sulfuric acid, magnetically stirring for 9h in a water bath at 85 ℃, washing for multiple times, filtering, drying in a drying oven at 55 ℃, then putting into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 800 ℃ at the heating rate of 5 ℃/min for heat treatment for 3h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst.

Example 4

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 0.5h at 400 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.4M sulfuric acid, carrying out magnetic stirring for 10h in a water bath at 85 ℃, washing for multiple times, filtering, and drying in a drying oven at 65 ℃ to obtain a pyrolytic polymer;

2) adding 0.48g of zinc nitrate and 0.012g of ammonium fluoride into the 0.12g of pyrolytic polymer obtained in the step 1), mixing, adding ethanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 850 ℃ at the heating rate of 8 ℃/min for heat treatment for 2h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.4M sulfuric acid, magnetically stirring for 10h in 85 ℃ water bath, washing with water for multiple times, filtering, drying in a 65 ℃ oven, putting into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 1000 ℃ at the heating rate of 15 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst.

Example 5

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 1h at 300 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.45M sulfuric acid, carrying out magnetic stirring for 8h in a water bath at 75 ℃, carrying out water washing for multiple times, filtering, and drying in an oven at 60 ℃ to obtain a pyrolytic polymer;

2) adding 0.48g of zinc chloride and 0.24g of ammonium fluoride into the 0.12g of pyrolytic polymer obtained in the step 1), mixing, adding methanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 1000 ℃ at the heating rate of 15 ℃/min for heat treatment for 1h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.45M sulfuric acid, magnetically stirring for 8h in 75 ℃ water bath, washing for many times, filtering, drying in a 60 ℃ oven, putting into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 10 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst.

Example 6

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 1h at 300 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.5M sulfuric acid, carrying out magnetic stirring for 8h in a water bath at 75 ℃, carrying out water washing for multiple times, filtering, and drying in an oven at 60 ℃ to obtain a pyrolytic polymer;

2) adding 0.12g of zinc chloride, 0.24g of zinc sulfate and 0.12g of ammonium fluoride into the 0.12g of the pyrolytic polymer obtained in the step 1), mixing, adding ethanol, grinding uniformly and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 1000 ℃ at the heating rate of 15 ℃/min for heat treatment for 1h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.45M sulfuric acid, magnetically stirring for 8h in 75 ℃ water bath, washing for many times, filtering, drying in a 60 ℃ oven, putting into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 15 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst.

Example 7

1) placing the waste cosmetic cotton in a tubular furnace, carrying out pre-carbonization treatment for 1.5h at 300 ℃ to remove internal grease to form a standard carbon material, then placing the standard carbon material in 0.45M sulfuric acid, carrying out magnetic stirring for 8h in a water bath at 75 ℃, washing for many times, filtering, and drying in an oven at 60 ℃ to obtain a pyrolytic polymer;

2) adding zinc sulfate (0.12g), zinc nitrate (0.24g) and ammonium fluoride (0.06g) into the pyrolytic polymer (0.12g) obtained in the step 1), mixing, adding methanol, grinding uniformly, and drying to obtain a precursor;

3) putting the precursor in the step 2) into a tubular furnace, introducing nitrogen for protection in the whole process, heating to 1000 ℃ at the heating rate of 10 ℃/min for heat treatment for 3h, naturally cooling to room temperature after the heat treatment is finished, then putting the precursor into 0.45M sulfuric acid, magnetically stirring for 8h in 75 ℃ water bath, washing for many times, filtering, drying in a 60 ℃ oven, putting the precursor into the tubular furnace again, introducing nitrogen for protection in the whole process, heating to 950 ℃ at the heating rate of 5 ℃/min for heat treatment for 1h, and naturally cooling to room temperature after the heat treatment is finished, thus obtaining the carbon-based oxygen reduction reaction catalyst.

Claims

1. A preparation method of a carbon-based oxygen reduction reaction catalyst is characterized by comprising the following steps:

2. The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein the temperature of the pre-carbonization treatment in the step 1) is 200-400 ℃, and the treatment time is 0.5-2 h.

3. The method for preparing the carbon-based oxygen reduction catalyst according to claim 1, wherein the zinc salt in the step 2) is one or a combination of any of zinc chloride, zinc sulfate and zinc nitrate.

4. The method of preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein the solvent in the step 2) is methanol or ethanol.

5. The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein the acid washing in step 1) and step 3) is performed under magnetic stirring in 0.4-0.6M sulfuric acid at 70-85 ℃ for 6-10 h.

6. A carbon-based oxygen reduction catalyst prepared according to the method of claim 1, wherein the catalyst is an N, F co-doped porous carbon-based structure having a specific surface area greater than 2000m².g^-1。