WO2018121365A1

WO2018121365A1 - Carbon-based oxygen reduction catalyst, preparation method therefor and use thereof

Info

Publication number: WO2018121365A1
Application number: PCT/CN2017/117301
Authority: WO
Inventors: 邓立波; 钟文华; 张培新; 任祥忠; 李永亮
Original assignee: 深圳大学
Priority date: 2016-12-28
Filing date: 2017-12-19
Publication date: 2018-07-05
Also published as: CN106803595B; CN106803595A

Abstract

Enclosed in the present invention is a carbon-based oxygen reduction catalyst, a preparation method therefor and use thereof. The method comprises: pre-oxidizing biomass in the air, uniformly mixing the product obtained from pre-oxidization with a pore forming agent and a catalyst, and obtaining the mixture; carbonizing the mixture under an inert gas protection condition, cooling to room temperature after carbonizing, removing the pore forming agent product and the catalyst product from the carbonization product by means of an acid, then washing several times and drying, and obtaining biomass based active carbon; performing a plasma treatment on the biomass based active carbon, so that a carbon-based oxygen reduction catalyst is obtained. Compared with the prior art, the present invention has the advantage that the carbon-based oxygen reduction catalyst has the appearance of having etched grooves and holes, has a specific surface area being as high as 1800 m²•g^-1, and has both microporous properties and mesoporous properties. The prepared carbon-based oxygen reduction catalyst has an oxygen reduction performance conforming to a four-electron pathway and has an improved initial potential and limit current density, being an efficient carbon-based oxygen reduction catalyst.

Description

Carbon-based oxygen reduction catalyst and preparation method and application thereof

Technical field

The invention relates to the field of electrochemical energy, in particular to a carbon-based oxygen reduction catalyst and a preparation method and application thereof.

Background technique

Energy shortages, environmental pollution and lack of resources are the most important challenges facing human society today. Developing sustainable clean energy and advanced energy storage technologies provide a good way to solve these problems. As an energy storage and output device, the battery has important research significance. Among them, fuel cells and metal-air batteries, as a kind of green energy source, have the advantages of non-toxicity, no pollution, stable discharge voltage, high specific energy and long storage life, making them a new generation battery with impossible development potential. Oxygen reduction reaction is an important electrode reaction in energy conversion systems such as fuel cells and metal-air batteries. However, the slow oxygen reduction reaction of the cathode becomes a key factor restricting its development. Finding a suitable cathode catalyst can effectively improve the charge and discharge performance and reversibility of fuel cells and metal-air batteries, thereby improving the cathode performance of the battery. The commonly used catalysts are mainly divided into three categories: the first type is carbon material and carbon as a carrier-supported precious metal catalyst (Pt, Pd, etc.); the second type is a metal oxide catalyst such as manganese dioxide, iron oxide, and tetraoxide Iron, copper oxide, etc.; the third type is a multi-metal catalyst of perovskite. Among them, carbon-supported platinum and platinum alloy catalysts are the best and most widely used oxygen reduction catalysts, but their high price and low reserves restrict the commercialization of fuel cells and metal-air batteries. The development of low-cost, high-efficiency non-precious metal oxygen reduction catalysts has become an urgent task for the development of fuel cells and metal-air batteries. Recent studies have shown that carbon materials, especially carbon materials prepared from biomass as raw materials, have a series of advantages and are expected to be an excellent substitute for platinum catalysts. However, the catalytic activity of carbon materials is still not high.

Therefore, the prior art has yet to be improved and developed.

Summary of the invention

In view of the above deficiencies of the prior art, the present invention aims to provide a carbon-based oxygen reduction catalyst and a preparation method and application thereof, aiming at solving the problem that the catalytic activity of the carbon material prepared by using the biomass as a raw material is not high.

The technical solution of the present invention is as follows:

A method for preparing a carbon-based oxygen reduction catalyst, comprising:

Step A, the biomass is pre-oxidized in the air, and the product obtained by pre-oxidation is uniformly mixed with the pore-forming agent and the catalyst to obtain a mixture;

Step B, carbonizing the mixture under inert gas protection conditions, carbonizing and cooling to room temperature, then removing the pore former product and the catalyst product in the carbonized product with an acid, washing several times, and drying to obtain a biomass-based activated carbon;

Step C: performing plasma treatment on the biomass-based activated carbon to obtain a carbon-based oxygen reduction catalyst.

The method for preparing a carbon-based oxygen reduction catalyst, wherein, in the step A, the pre-oxidation conditions are: a temperature of 200 to 300 ° C, and a time of 1 to 5 h.

The method for preparing a carbon-based oxygen reduction catalyst, wherein in the step A, the pore-forming agent is one of zinc chloride and potassium hydroxide; and the catalyst is iron chloride or iron nitrate. One.

The method for preparing a carbon-based oxygen reduction catalyst, wherein in the step A, the mass ratio of the product obtained by pre-oxidation to the pore former and the catalyst is uniformly mixed: 1:1:1 to 1:5:5.

The method for preparing a carbon-based oxygen reduction catalyst, wherein in the step B, the carbonization conditions are: a temperature of 600 to 900 ° C, a time of 1 to 3 h, and a heating rate of 2 to 5 ° C / min.

The method for preparing a carbon-based oxygen reduction catalyst, wherein in the step B, the acid is one of a sulfuric acid solution and a hydrochloric acid solution; and the drying condition is: a temperature of 50 to 100 ° C, and the time is 6 ~ 24h.

The method for preparing a carbon-based oxygen reduction catalyst, wherein the step C is specifically: selecting one of a low frequency, an intermediate frequency, and a high frequency under a condition of a vacuum degree of 50 to 200 Pa, and generating an air plasma pair The biomass-based activated carbon is treated to obtain a carbon-based oxygen reduction catalyst.

The method for preparing a carbon-based oxygen reduction catalyst, wherein, in the step C, the plasma treatment time is 0 to 500 s, and the time is not taken as 0.

A carbon-based oxygen reduction catalyst produced by the method for producing a carbon-based oxygen reduction catalyst as described above.

A use of a carbon-based oxygen reduction catalyst, wherein the carbon-based oxygen reduction catalyst as described above is used as an oxygen reduction catalyst material of a fuel cell or a metal-air battery.

Advantageous Effects: The present invention prepares a carbon-based oxygen reduction catalyst by first pre-oxidizing biomass, then uniformly mixing with a selected pore-forming agent and a catalyst, and then separately performing carbonization and air plasma treatment to prepare a carbon-based oxygen reduction catalyst. The oxygen reduction catalyst has a morphology of groove and pore etching, and has a specific surface area of up to 1800 m ² ·g ^-1 , and has microporosity and mesoporous properties, thereby remarkably improving electrocatalytic activity.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a scanning electron micrograph of a porous carbon obtained by carbonization of chitin in Example 1 of the present invention.

2 is a scanning electron micrograph of a porous carbon obtained by carbonization of chitin by air plasma treatment for 120 s in Example 1 of the present invention.

3 is a cyclic voltammogram of porous carbon obtained by carbonization of chitin and its air plasma treatment for 120 s in Example 1 of the present invention.

4 is a linear scan curve of the porous carbon obtained by carbonization of chitin and its air plasma treatment for 120 s in Example 1 of the present invention.

Fig. 5 is a scanning electron micrograph of a porous carbon obtained by carbonization of a lotus leaf in Example 2 of the present invention.

Fig. 6 is a scanning electron micrograph of the porous carbon obtained by carbonization of a lotus leaf after air plasma treatment for 120 s in Example 2 of the present invention.

Figure 7 is a graph showing the cyclic voltammetry of porous carbon obtained by carbonization of a lotus leaf in Example 2 of the present invention and its treatment by air plasma for 120 s.

Fig. 8 is a linear scanning curve of the porous carbon obtained by carbonization of the lotus leaf in Example 2 of the present invention and after being subjected to air plasma treatment for 120 s.

detailed description

The present invention provides a carbon-based oxygen reduction catalyst, a preparation method and application thereof, and the present invention will be further described in detail below in order to make the objects, technical solutions and effects of the present invention more clear and clear. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The present invention is directed to the current catalytic activity of carbon materials is still not high, and proposes a synergistic effect of first activating biomass and graphitization, and then separately performing different degrees of air plasma treatment. The method can effectively increase the active site of the carbon material, thereby enhancing the oxygen reduction performance of the carbon material non-precious metal catalyst.

Specifically, the present invention provides a preferred embodiment of a method for preparing a carbon-based oxygen reduction catalyst, which comprises:

In the step A, the pre-oxidation conditions are: the temperature is between 200 and 300 ° C (eg, 250 ° C), and the time is between 1 and 5 h (eg, 3 h). The pore former may be one of zinc chloride and potassium hydroxide; and the catalyst may be one of ferric chloride and ferric nitrate. The mass ratio of the product obtained by pre-oxidation to the pore former and the catalyst is uniformly 1:1:1 to 1:5:5, because the biomass-based activated carbon obtained has a higher specific surface area at the mass ratio. At the same time, it has better microporous and mesoporous properties.

Specifically, the step B is: placing the mixture into a porcelain boat, performing carbonization at a high temperature under inert gas protection conditions in a tube furnace, carbonizing, cooling to room temperature, and then removing the pore former in the carbonized product with an acid. The product and the catalyst product were washed several times and blast dried to obtain a biomass-based activated carbon.

Wherein, the inert gas is one of nitrogen gas and argon gas, and the carbonization condition is: a temperature of 600-900 ° C (such as 800 ° C), a time of 1 to 3 h (such as 2 h), and a heating rate of 2 to 5 °C/min. The acid may be one of a sulfuric acid solution, a hydrochloric acid solution, etc., and the concentration of the acid solution is 0.5 to 3 mol/L. The conditions for the blast drying are: a temperature of 50 to 100 ° C (eg, 80 ° C), and a time of 6 to 24 h (eg, 15 h).

The plasma treatment technology is a technology in which a rare air emits a glow by a glow discharge at a low voltage, and belongs to the cold plasma category, and has the following basic characteristics: (1) a high-purity reaction substance can be obtained; (2) a reaction The particle activity is higher than the thermal plasma, and the film deposition temperature is lower than the high temperature vapor phase chemical deposition; (3) the high energy metastable substance which is difficult to obtain by other methods can be obtained by the non-thermal equilibrium chemical reaction and the control of the ion energy; (4) The ionization rate is high. The free path length of the particle motion can complete the etching of the grooves and holes of the sub-micron and deep sub-micron materials; (5) The plasma has a short duration and can only last for several tens of hours or even several minutes. The use of air plasma to treat carbon materials is expected to introduce hydrophilic oxygen-containing groups on the surface of the material to improve the wettability of the carbon material in the electrolyte. More importantly, plasma etching will produce a large amount of material in the material. Defects, these defects will become catalytically active centers, thereby significantly increasing the electrocatalytic activity.

The above step C is specifically: under a certain vacuum condition, selecting a suitable radio frequency, generating an air plasma, and performing plasma treatment on the biomass-based activated carbon to obtain a highly efficient carbon-based oxygen reduction catalyst. The selected vacuum degree may be 50-200 Pa; the radio frequency may be one of a low frequency, an intermediate frequency, and a high frequency; the plasma processing time is 0-500 s, and the time is not taken as 0. The invention utilizes plasma to treat biomass-based activated carbon, so that the prepared carbon-based oxygen reduction catalyst has a morphology of groove and pore etching, and has a specific surface area of up to 1800 m ² ·g ^-1 , and has microporosity and mesoporous properties. Thereby significantly improving the electrocatalytic activity.

The invention firstly pre-oxidizes the biomass, and then mixes with the selected suitable pore-forming agent and catalyst uniformly, and then separately performs carbonization and air plasma treatment to prepare a carbon-based oxygen reduction catalyst, thereby effectively improving the carbon-based oxygen reduction catalyst. Cathode performance. Compared with the prior art, the present invention has the following advantages: the carbon-based oxygen reduction catalyst prepared by the invention has the morphology of groove and pore etching, and has a specific surface area of up to 1800 m ² ·g ^-1 , and has micropores and Mesoporous properties. The prepared carbon-based oxygen reduction catalyst has a four-electron approach, has a better initial potential and a limiting current density, and is a high-efficiency carbon-based oxygen reduction catalyst. The preparation conditions of the invention are relatively mild, safe, environmentally friendly, convenient and inexpensive.

Based on the above method, the present invention also provides a carbon-based oxygen reduction catalyst which is produced by the method for producing a carbon-based oxygen reduction catalyst as described above. The carbon-based oxygen reduction catalyst prepared by the invention has the morphology of groove and pore etching, and has a specific surface area of up to 1800 m ² ·g ^-1 , and has microporosity and mesoporous properties, thereby significantly improving oxygen reduction ability.

The present invention also provides an application of a carbon-based oxygen reduction catalyst characterized in that the carbon-based oxygen reduction catalyst as described above is used as an oxygen reduction catalyst material of a fuel cell or a metal-air battery.

The specific application method is as follows: uniformly mixing the carbon-based oxygen reduction catalyst with a dispersing agent and a film-forming agent, and uniformly mixing the carbon-based oxygen reduction catalyst material; or the metal-air battery; The mass ratio of the catalyst to the dispersant was 1 mg/ml, and the amount of the film-forming agent was a small amount.

The invention also provides a preparation method of a fuel cell and a metal-air battery cathode catalyst. According to the above ratio, the carbon-based oxygen reduction catalyst and the anhydrous ethanol dispersing agent are first mixed in a 10 ml strain bottle, and then ultrasonicated for 30 minutes. Then, 50 ul of Nafion film-forming agent was ultrasonicated for 20 min to obtain a fuel cell, metal-air battery cathode catalyst suspension.

First, use a pipetting gun to measure 5 ul of the film forming agent Nafion, evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. Then use a pipette to measure 10 ul of the fuel cell and metal-air battery cathode catalyst suspension, which are evenly dropped on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. A three-electrode system was prepared using 0.1 M KOH as an electrolyte. The cyclic voltammetry curve was tested at a potential window of 0.2 to -0.8 V, a rotational speed of 0 rpm, and a scanning speed of 10 mV/s; at the same potential window and scanning speed, a linear scanning curve with a rotational speed of 1600 rpm was sequentially tested. The results show that the high-efficiency carbon-based oxygen reduction catalyst prepared by the invention follows the four-electron route and has high oxygen reduction ability.

The invention will now be described in detail by way of specific examples.

Example 1

Preparation of chitin-based porous carbon (PCZF-800): Take 3g of chitin, put it in a porcelain boat and pre-oxidize it for 2h in an air atmosphere at 250°C. After the reaction is finished, the temperature of the reaction system will be lowered to room temperature. Oxidized chitin based carbon material. According to ZnCl ₂ , FeCl ₃ and pre-oxidized chitin-based carbon material, the mixture is mixed at a mass ratio of 1:3:1, and heated at a heating rate of 5 ° C/min to 800 ° C for 2 h under N ₂ atmosphere to obtain impurities. Chitin based porous carbon. After cooling to room temperature, the Fe, Zn metal compound in the chitin-based porous carbon was removed with a 2 M HCl solution, and washed 5 times with deionized water, and dried to obtain a chitin-based porous carbon. 1 is a scanning electron micrograph of a porous carbon obtained by carbonization of chitin in Example 1 of the present invention.

Preparation of high-efficiency chitin-based porous carbon-oxygen reduction catalyst (PCZF-800-120s): Take 3g of chitin, put it in a porcelain boat, pre-oxidize for 2h in an air atmosphere at 250 °C, after the reaction is over, the temperature of the reaction system drops. After room temperature, a pre-oxidized chitin-based carbon material is obtained. According to ZnCl ₂ , FeCl ₃ and pre-oxidized chitin-based carbon material, the mixture is mixed at a mass ratio of 1:3:1, and heated at a heating rate of 5 ° C/min to 800 ° C for 2 h under N ₂ atmosphere to obtain impurities. Chitin based porous carbon. After cooling to room temperature, the Fe, Zn metal compound in the chitin-based porous carbon was removed with a 2 M HCl solution, and washed 5 times with deionized water, and dried to obtain a chitin-based porous carbon. Then, the chitin-based porous carbon was placed under a vacuum of 80 Pa to adjust the radio frequency to a high frequency, and the generated air plasma was subjected to a chitin-based porous carbon treatment for 120 s to obtain a high-efficiency chitin-based porous carbon-oxygen reduction catalyst. 2 is a scanning electron micrograph of the porous carbon obtained by carbonization of chitin by air plasma treatment for 120 s in Example 1 of the present invention.

3 is a cyclic voltammogram of porous carbon obtained by carbonization of chitin and its air plasma treatment for 120 s in Example 1 of the present invention. The sample preparation process and performance test: 4 mg of chitin carbonized porous carbon and its carbon after air treatment for 120 s in a 10 ml strain bottle, and then 4 ml of absolute ethanol was obtained to make the dispersion density 1 mg/ml. Ultrasound for 30 min, then add 50 ul of film-forming agent Nafion for 20 min. First, use a pipetting gun to measure 5 ul of the film forming agent Nafion, evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. Then, use a pipetting gun to measure 10 ul of the prepared catalyst suspension, and evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. A three-electrode system was prepared using 0.1 M KOH as an electrolyte. The cyclic voltammetry curve was tested at a potential window of 0.2 to -0.8 V, a rotation speed of 0 rpm, and a scanning speed of 10 mV/s. The results show that under the same catalyst loading condition, the chitin-based porous carbon after 120 s treatment with air plasma has a more positive and more obvious oxygen reduction peak (the oxygen reduction peak potential is shifted from -0.229V to -0.161V). ).

4 is a linear scan curve of the porous carbon obtained by carbonization of chitin and its air plasma treatment for 120 s in Example 1 of the present invention. The preparation process and performance test: the porous carbon obtained by carbonization of 4 mg of chitin in a 10 ml strain bottle and its air plasma treatment for 120 s, and then 4 ml of absolute ethanol is obtained, so that the dispersion density is 1 mg/ml. Ultrasound for 30 min, then add 50 ul of film-forming agent Nafion for 20 min. First, use a pipetting gun to measure 5 ul of the film forming agent Nafion, evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. Then, use a pipetting gun to measure 10 ul of the prepared catalyst suspension, and evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. A three-electrode system was prepared using 0.1 M KOH as an electrolyte. The linear scan was tested under the conditions of a potential window of 0.2 to -0.8 V, a rotation speed of 1600 rpm, and a scanning speed of 10 mV/s. The results show that the chitin-based porous carbon after 120 s of air plasma treatment has a more positive initial potential (positive shift from -0.006 V to -0.002 V) and a larger limiting current density under the same catalyst loading conditions ( Increased from 2.72 mAcm ^-2 to 4.08 mAcm ^-2 ).

Example 2

Preparation of lotus leaf porous carbon (CK): Take 3g of lotus leaf sample, wash and chop, transfer to porcelain boat, and mix according to KOH and dried lotus leaf at a mass ratio of 3:1, in N ₂ The mixture was heated at a heating rate of 5 ° C / min under an atmosphere to a constant temperature of 400 ° C for 1 h, and then at 800 ° C for 2 h to obtain a lotus leaf-based porous carbon containing impurities. Upon cooling to room temperature, the KOH powder in the lotus leaf-based porous carbon was removed with a 1 M HCl solution, and washed 5 times with deionized water, and dried to obtain an impurity-free, lotus-based porous carbon. Here, FIG. 5 is a scanning electron micrograph of the porous carbon obtained by carbonization of the lotus leaf in Example 2 of the present invention.

Preparation of high-efficiency lotus leaf-based porous carbon electrocatalyst (CK-120s): take 3g of lotus leaf sample, wash and chop, transfer to porcelain boat, and according to KOH and dry lotus leaf at a mass ratio of 3:1 The mixture was heated to a temperature of 5 ° C / min under a N ₂ atmosphere and heated to 400 ° C for 1 h, and then to 800 ° C for 2 h to obtain a lotus leaf-containing porous carbon containing impurities. Upon cooling to room temperature, the KOH powder in the lotus leaf-based porous carbon was removed with a 1 M HCl solution, and washed 5 times with deionized water, and dried to obtain an impurity-free, lotus-based porous carbon. Then, the lotus leaf-based porous carbon was placed under a vacuum of 80 Pa to adjust the radio frequency to a high frequency, and the generated air plasma was subjected to 120 s treatment of the lotus-based porous carbon to obtain a highly efficient lotus-based porous carbon electrocatalyst. 6 is a scanning electron micrograph of the porous carbon obtained by carbonization of the lotus leaf after air plasma treatment for 120 s in Example 2 of the present invention.

Figure 7 is a graph showing the cyclic voltammetry of porous carbon obtained by carbonization of a lotus leaf in Example 2 of the present invention and its treatment by air plasma for 120 s. The preparation process and performance test: 4mg of the carbonized porous carbon obtained by the lotus leaf in the 10ml strain bottle and the carbon after 120s of air plasma treatment, and then 4ml of absolute ethanol is obtained, so that the dispersion density is 1mg/ml. Ultrasound for 30 min, then add 50 ul of film-forming agent Nafion for 20 min. First, use a pipetting gun to measure 5 ul of the film forming agent Nafion, evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. Then, use a pipetting gun to measure 10 ul of the prepared catalyst suspension, and evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. A three-electrode system was prepared using 0.1 M KOH as an electrolyte. The cyclic voltammetry curve was tested at a potential window of 0.2 to -0.8 V, a rotation speed of 0 rpm, and a scanning speed of 10 mV/s. The results show that under the same catalyst loading condition, the lotus-based porous carbon after 120 s of air plasma treatment has a more positive and more obvious oxygen reduction peak (the oxygen reduction peak potential is shifted from -0.286V to -0.174V). ).

Fig. 8 is a linear scanning curve of the porous carbon obtained by carbonization of the lotus leaf in Example 2 of the present invention and after being subjected to air plasma treatment for 120 s. The preparation process and performance test: 4 mg of lotus leaf carbonized in a 10 ml strain bottle and its air plasma treatment for 120 s, and then 4 ml of absolute ethanol, so that the dispersion density is 1 mg/ml. Ultrasound for 30 min, then add 50 ul of film-forming agent Nafion for 20 min. First, use a pipetting gun to measure 5 ul of the film forming agent Nafion, evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. Then, use a pipetting gun to measure 10 ul of the prepared catalyst suspension, and evenly drip on the center of the rotating glass glass carbon electrode, and then baked with infrared light for 1-2 minutes. A three-electrode system was prepared using 0.1 M KOH as an electrolyte. The linear scan was tested under the conditions of a potential window of 0.2 to -0.8 V, a rotation speed of 1600 rpm, and a scanning speed of 10 mV/s. The results show that under the same catalyst loading condition, the lotus-based porous carbon after 120 s of air plasma treatment has a more positive initial potential (positive shift from -0.134 V to -0.056 V) and a larger limiting current density ( Increased from 2.10 mAcm ^-2 to 3.74 mAcm ^-2 ).

In summary, the carbon-based oxygen reduction catalyst of the present invention, and the preparation method and application thereof, the invention firstly pre-oxidizes the biomass, and then mixes with the selected suitable pore-forming agent and catalyst, and then separately. The carbon-based oxygen reduction catalyst is prepared by carbonization and plasma treatment to effectively improve the cathode performance of the carbon-based oxygen reduction catalyst. Compared with the prior art, the present invention has the following advantages: the carbon-based oxygen reduction catalyst prepared by the invention has the morphology of groove and pore etching, and has a specific surface area of up to 1800 m ² ·g ^-1 , and has micropores and Mesoporous properties. The prepared carbon-based oxygen reduction catalyst has a four-electron approach, has a better initial potential and a limiting current density, and is a high-efficiency carbon-based oxygen reduction catalyst. The preparation conditions of the invention are relatively mild, safe, environmentally friendly, convenient and inexpensive.

It is to be understood that the application of the present invention is not limited to the above-described examples, and those skilled in the art can make modifications and changes in accordance with the above description, all of which are within the scope of the appended claims.

Claims

A method for preparing a carbon-based oxygen reduction catalyst, comprising:

Step A, the biomass is pre-oxidized in the air, and the product obtained by pre-oxidation is uniformly mixed with the pore-forming agent and the catalyst to obtain a mixture;

Step B, carbonizing the mixture under inert gas protection conditions, carbonizing and cooling to room temperature, then removing the pore former product and the catalyst product in the carbonized product with an acid, washing several times, and drying to obtain a biomass-based activated carbon;

Step C: performing plasma treatment on the biomass-based activated carbon to obtain a carbon-based oxygen reduction catalyst.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein in the step A, the pre-oxidation conditions are: a temperature of 200 to 300 ° C, and a time of 1 to 5 hours.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein in the step A, the pore-forming agent is one of zinc chloride and potassium hydroxide; and the catalyst is chlorinated. One of iron and ferric nitrate.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein in the step A, the mass ratio of the product obtained by pre-oxidation to the pore former and the catalyst is uniformly 1:1:1 to 1: 5:5.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein in the step B, the carbonization condition is: a temperature of 600 to 900 ° C, a time of 1 to 3 h, and a heating rate of 2 ~ 5 ° C / min.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein in the step B, the acid is one of a sulfuric acid solution and a hydrochloric acid solution; and the drying condition is: a temperature of 50 ~100 ° C, time is 6 ~ 24h.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein the step C is specifically: selecting one of a low frequency, an intermediate frequency, and a high frequency under a condition of a vacuum degree of 50 to 200 Pa. The generated air plasma treats the biomass-based activated carbon to obtain a carbon-based oxygen reduction catalyst.
The method for preparing a carbon-based oxygen reduction catalyst according to claim 1, wherein in the step C, the plasma treatment time is 0 to 500 s, and the time is not taken as 0.
A carbon-based oxygen reduction catalyst produced by the method for producing a carbon-based oxygen reduction catalyst according to any one of claims 1 to 8.
Use of a carbon-based oxygen reduction catalyst characterized in that the carbon-based oxygen reduction catalyst according to claim 9 is used as an oxygen reduction catalyst material for a fuel cell or a metal-air battery.