CN102626649A - Oxygen reduction non-noble metal catalyst and preparation method thereof - Google Patents

Abstract

The invention provides an oxygen reduction non-noble metal catalyst and a preparation method thereof, belonging to the technical field of fuel cells. A nitrogen-doped non-precious metal fuel cell catalyst with a graphite-like structure is formed by introducing a nitrogen-containing monomer into the interlayer of a layered inorganic compound, and interlayer polymerization and pyrolysis. The near-sealing effect of the layered compound is used to effectively reduce the loss of active nitrogen and improve the degree of graphitization of the catalyst, thereby improving the catalytic activity and stability of the non-noble metal catalyst. The method of the invention is simple and easy, and the production cost is low. The catalyst prepared by the invention has good oxygen reduction catalytic activity and stability, and can be applied to fuel cells using proton exchange membranes as electrolytes. The fuel cell manufactured by the invention is widely used in electric automobiles, various spacecraft, portable electronic equipment, such as video cameras, notebook computers, electric toys and the like.

Description

A kind of oxygen reduction non-noble metal catalyst and preparation method thereof

1. Technical field:

The invention belongs to the technical field of fuel cells, in particular to an oxygen-reducing non-noble metal catalyst and a preparation method thereof.

2. Background technology:

Fuel cells have the advantages of high energy conversion efficiency, environmental friendliness, and rapid start-up at room temperature, and are considered to be the most promising chemical power sources for electric vehicles and other civilian applications in the future. At present, the main cathode catalysts for proton exchange membrane fuel cells (PEMFCs) are platinum-based catalysts, but their disadvantages such as high cost, lack of resources, and easy poisoning seriously restrict the development of fuel cells. Therefore, it is of great significance to develop a low-cost and high-performance non-noble metal catalyst for PEMFCs cathode.

In recent years, a lot of research has been done on non-precious metal catalysts at home and abroad. Chinese invention patent 201110138139.9 discloses "a carbon-supported CoN fuel cell catalyst and its preparation method and application". Under the protection of an inert gas atmosphere, carbon-supported CoN fuel is formed by high-temperature heat treatment of a mixture of Co metal salts, nitrogen compounds and carbon materials battery catalyst. The carbon-supported CoN fuel cell catalyst prepared by this method has certain catalytic oxygen reduction activity in alkaline environment. However, the dissolution of metal Co under acidic conditions will seriously affect the stability and activity of the catalyst. Chinese invention patent 200610113692.6 discloses "a non-precious metal catalyst for direct methanol fuel cell cathode and its preparation method". The carbon-supported transition Metal Nitride Catalysts. The carbon-loaded transition metal nitride catalyst prepared by the method has a certain oxygen reduction activity, but the free metal ions in the catalyst will greatly accelerate the attenuation and aging of the electrolyte membrane and reduce the service life of the fuel cell. Therefore, there is still a certain gap between the catalyst obtained by the above method and the fuel cell catalyst requirements.

3. Contents of the invention:

The object of the present invention is to provide an oxygen-reducing non-noble metal catalyst and a preparation method thereof, aiming at the disadvantages of the existing fuel cell Pt/C catalysts, which are high in cost and lack of resources. In the present invention, firstly, pyrrole or aniline monomer is introduced into the interlayer of the layered inorganic compound, and then a polypyrrole or polyaniline precursor with two-dimensional characteristics is formed between the layers through chemical oxidation polymerization, and finally pyrolyzed at high temperature to form a polypyrrole or polyaniline precursor with Nitrogen-doped non-noble metal fuel cell catalysts with graphite-like structure. The present invention selects polypyrrole or polyaniline, which has a graphite-like structure and is easy to graphitize, as a nitrogen-containing precursor, and cleverly utilizes the unique space confinement effect of layered inorganic compounds to prepare a nano-sheet graphite-like structure with controllable size and thickness. The nearly closed structure of the layered inorganic compound is used to effectively reduce the loss of active nitrogen during the pyrolysis process and increase the content of active nitrogen, thereby improving the catalytic activity and stability of the non-noble metal catalyst.

The object of the present invention is achieved in that a kind of oxygen-reducing non-precious metal catalyst and preparation method thereof, its specific method step comprises:

(1) Preparation of layered compound suspensions intercalated with aniline or pyrrole

Weigh the layered compound and aniline or pyrrole according to the mass ratio of layered compound: aniline or pyrrole is 1:0.1~4, first disperse the layered compound in deionized water, and stir ultrasonically for 3~8 hours to form a mass concentration of 0.01~ 0.1 g/ml layered compound suspension; measure ethanol or acetone or acetonitrile according to the volume ratio of layered compound suspension: ethanol or acetone or acetonitrile, and dissolve aniline or pyrrole in ethanol or acetone or acetonitrile, and added to the layered compound suspension, stirred at 10-60°C for 10-40 hours to form a layered compound suspension intercalated with aniline or pyrrole.

(2) Interlayer polymerization of aniline or pyrrole

The layered compound suspension of the aniline or pyrrole intercalation obtained in step (1): the volume ratio of sulfuric acid or hydrochloric acid solution is 1: 0.1～0.5 Measure sulfuric acid or hydrochloric acid solution, wherein the concentration of sulfuric acid or hydrochloric acid solution is 0.5～1.5 moles per liter; by aniline or pyrrole: the mass ratio of oxidant is 1: 0.5～2 to take oxidant, and be dissolved in deionized water to form mass concentration and be 0.1～1 g/ml oxidant solution; Sulfuric acid or hydrochloric acid solution is added to step (1) In the layered compound suspension obtained by aniline or pyrrole intercalation, stir for 1 to 3 hours, then add the oxidizing agent solution to the suspension at a rate of 0.1 to 1 ml/min, and stir at 0 to 10°C for 10 ~ 30 hours, and finally vacuum filtered, washed three times with deionized water and three times with absolute ethanol, dried at 60°C for 24 hours, and ground to obtain layered compound interlayer polyaniline or polypyrrole.

(3) Preparation of nitrogen-doped graphene-like catalyst

The layered compound interlayer polyaniline or polypyrrole obtained in step (2) is placed in a tube furnace, and the inert gas is fed into the tube furnace at a flow rate of 50 to 200 ml/min for 0.5 to 1 hour, and then kept inert Gas flow rate, at a heating rate of 6-20°C/min, first raise the tube furnace to 120-180°C and keep it for 1-4 hours, then continue to heat up to 700-1000°C and keep it for 1-4 hours, cool to room temperature, and grind , obtain layered compound interlayer nitrogen-doped graphene; Press layered compound: hydrofluoric acid mass ratio 1: 2 takes hydrofluoric acid, wherein hydrofluoric acid mass concentration is 40%; First above-mentioned layered compound interlayer nitrogen Doped graphene is dispersed in ethanol, and ultrasonically stirred for 3 to 8 hours to form a layered compound interlayer nitrogen-doped graphene suspension with a mass concentration of 0.1 to 1 g/ml, and then hydrofluoric acid is slowly added to the layered compound In the interlayer nitrogen-doped graphene-like suspension, ultrasonically stirred and reacted for 10 to 20 hours, and finally filtered, washed with deionized water for 3 times and absolute ethanol for 3 times, dried at 60°C for 24 hours, and the nitrogen-doped graphene was obtained after grinding. Graphene catalyst.

Wherein the layered compound is one of montmorillonite, kaolin, hydrotalcite and brucite, wherein the oxidant is one of ammonium persulfate, hydrogen peroxide, potassium permanganate and ferric chloride; The inert gas is one of nitrogen and argon.

After the present invention adopts above-mentioned technical scheme, mainly have the following advantages:

(1) The catalyst has good electrical conductivity, a two-dimensional sheet structure similar to graphene, and a high degree of graphitization, thereby ensuring good stability of the catalyst.

(2) The nitrogen doping efficiency is high and the chemical state composition of nitrogen can be controlled, so that the catalyst has excellent oxygen reduction catalytic performance.

(3) There are no metal ions in any form in the catalyst, and there is no problem of accelerating the degradation of the electrolyte membrane during the use of the catalyst.

The method of the invention is simple and easy, and the production cost is low. The nitrogen-doped graphene-like catalyst prepared by the invention has excellent oxygen reduction catalytic activity, stability and methanol resistance. It can be applied to fuel cells with proton exchange membrane as electrolyte, such as gas electrodes of hydrogen-oxygen proton exchange membrane fuel cells and direct methanol fuel cells. The fuel cell manufactured by the invention is widely used in electric automobiles, various spacecraft, portable electronic equipment, such as video cameras, notebook computers, electric toys and the like.

4. Description of drawings:

Fig. 1 is the oxygen reduction linear scan curve of the nitrogen-doped graphene-like catalyst obtained in Example 1 and the commercialized Pt/C (platinum mass percentage 40%) catalyst of British Jonhson-Matthey Company on the rotating disk electrode.

Among the figure: curve 1 is that the nitrogen-doped graphene-like catalyst prepared in embodiment 1 is the working electrode, the silver/silver chloride electrode is the reference electrode, the platinum ring is the counter electrode, and the oxygen-saturated 0.5 mol/liter sulfuric acid aqueous solution is the electrolytic liquid, the oxygen reduction linear scan curve under the condition that the scan speed is 2 mV/s.

Curve 2 is that the commercialized Pt/C (platinum mass percentage 40%) catalyst of British Jonhson-Matthey Company is the working electrode, the silver/silver chloride electrode is the reference electrode, the platinum ring is the counter electrode, and the oxygen saturated 0.5 mol/liter sulfuric acid aqueous solution is the electrolyte, and the scanning speed is the oxygen reduction linear scanning curve under the condition of 2 mV/s.

Fig. 2 is the cyclic voltammetry graph of the nitrogen-doped graphene-like catalyst prepared in Example 2 and the commercialized Pt/C (platinum mass percent 40%) catalyst of British Jonhson-Matthey Company on the rotating disk electrode.

Among the figures: curves 1 to 2 are based on the nitrogen-doped graphene-like catalyst prepared in Example 2 as the working electrode, the silver/silver chloride electrode as the reference electrode, and the platinum ring as the counter electrode, nitrogen saturated with 0.5 mol/liter of sulfuric acid aqueous solution cyclic voltammetry curve under the conditions of electrolyte and scan speed of 50mV/s. Among them, the scanning circle number of curve 1 is the first circle, and the scanning circle number of curve 2 is the 800th circle.

Curves 3 to 4 are the commercialized Pt/C (platinum mass percent 40%) catalyst of British Jonhson-Matthey Company as the working electrode, the silver/silver chloride electrode as the reference electrode, and the platinum ring as the counter electrode, nitrogen saturation 0.5 mol/liter Sulfuric acid aqueous solution is the electrolyte, and the cyclic voltammetry curve is under the condition that the scanning speed is 50mV/s. Among them, the scanning circle number of curve 3 is the first circle, and the scanning circle number of curve 4 is the 800th circle.

Fig. 3 is the oxygen reduction linear scan curve before and after aging of the nitrogen-doped graphene-like catalyst prepared in Example 3.

In the figure: Curve 1 is the catalytic oxygen reduction linear scanning curve of the nitrogen-doped graphene-like catalyst prepared in Example 3 before aging.

Curve 2 is the linear scan curve of catalytic oxygen reduction after aging of the nitrogen-doped graphene-like catalyst prepared in Example 3.

FIG. 4 is a scanning electron microscope image of the nitrogen-doped graphene-like catalyst prepared in Example 4 at a magnification of 50,000 times.

Fig. 5 is a test curve of a proton exchange membrane hydrogen-oxygen fuel cell single cell in which the nitrogen-doped graphene-like catalyst prepared in Example 1 is used as the cathode oxygen reduction catalyst.

Among the figure: Curve 1 is the power curve of the fuel cell cathode catalyst based on the nitrogen-doped graphene-like catalyst prepared in Example 1, and curve 2 is based on the nitrogen-doped graphene-like catalyst prepared in Example 1 as the fuel cell cathode catalyst Polarization curve.

5. Specific implementation methods:

The present invention will be further described below in combination with specific embodiments.

Example 1

An oxygen-reducing non-noble metal catalyst and a preparation method thereof, the specific method steps comprising:

(1) Preparation of montmorillonite suspension for aniline intercalation

Weigh montmorillonite and aniline according to the mass ratio of montmorillonite: aniline of 1:1, first disperse montmorillonite in deionized water, and ultrasonically stir for 5 hours to form a montmorillonite suspension with a mass concentration of 0.05 g/ml Measure ethanol by montmorillonite suspension: the volume ratio of ethanol is 1: 0.5, dissolve aniline in ethanol, and join in the above-mentioned montmorillonite suspension, stir 30 hours at 20 ℃, form the montmorillonite intercalation of aniline Desoil suspension.

(2) Interlayer polymerization of aniline

The montmorillonite suspension of the aniline intercalation obtained by step (1): the volume ratio of sulfuric acid solution 1: 0.3 measures sulfuric acid solution, wherein the concentration of sulfuric acid solution is 1 mole/liter; by aniline: the mass ratio of ammonium persulfate Ammonium persulfate is weighed at 1:1, and dissolved in deionized water to form a mass concentration of 0.5 g/ml ammonium persulfate solution; the sulfuric acid solution is first added to the aniline intercalated montmorillonite suspension obtained in step (1) solution, stirred for 2 hours, then ammonium persulfate solution was added to the above suspension at a rate of 0.5 ml/min, stirred and reacted at 5°C for 20 hours, and finally vacuum filtered, washed with deionized water for 3 times and absolute ethanol for 3 times Once, dry at 60°C for 24 hours and grind to obtain polyaniline interlayered with montmorillonite.

(3) Preparation of nitrogen-doped graphene-like catalyst

The montmorillonite interlayer polyaniline obtained in step (2) is placed in a tube furnace, and after 0.8 hours of nitrogen gas is passed into the tube furnace with a flow rate of 100 ml/min, the nitrogen flow rate is maintained and the temperature is raised at 10° C./min. Speed, first raise the tube furnace to 150°C for 3 hours, then continue to heat up to 900°C for 3 hours, cool to room temperature, and grind to obtain montmorillonite interlayer nitrogen-doped graphene; according to montmorillonite: hydrogen Hydrofluoric acid mass ratio 1:2 Weigh hydrofluoric acid, wherein the mass concentration of hydrofluoric acid is 40%; first disperse the above-mentioned montmorillonite interlayer nitrogen-doped graphene in ethanol, and ultrasonically stir for 5 hours to form a mass concentration of 0.5% gram/milliliter montmorillonite interlayer nitrogen-doped graphene-like suspension, then slowly add hydrofluoric acid into the above-mentioned montmorillonite interlayer nitrogen-doped graphene-like suspension, ultrasonically stir for 15 hours, and finally filter and deionize Washing with water for 3 times and absolute ethanol for 3 times, drying at 60° C. for 24 hours, and grinding to obtain a nitrogen-doped graphene-like catalyst.

(4) Oxygen reduction test of nitrogen-doped graphene-like catalyst

Weigh 2 mg of the nitrogen-doped graphene-like catalyst prepared in step (3) and add it to 200 microliters of absolute ethanol solution and ultrasonically oscillate for 10 minutes to disperse evenly. After drying at 60°C on the rotating disc electrode, pipette 5 microliters of 0.05% Nafion solution and drop it on the catalytic layer, and keep it at 60°C for 2 hours. Use this electrode as the working electrode, the platinum ring electrode and the silver/silver chloride electrode (Ag/AgCl) electrode as the auxiliary electrode and the reference electrode respectively, and measure the linear scan curve of oxygen reduction in a sulfuric acid solution saturated with oxygen at 0.5mol/L . The scan rate is 2mV/s, and the scan range is 0.9-0V (vs.Ag/AgCl). The test results are shown in curve 1 in Figure 1.

(5) Single-cell performance evaluation of nitrogen-doped graphene-like catalyst proton exchange membrane fuel cell electrode

The nitrogen-doped graphene-like catalyst electrode prepared in step (3) was used as the cathode of the proton exchange membrane fuel cell, and the catalyst loading was 3.7 mg/cm ² , and the traditional Pt/C gas porous electrode was used as the anode. The Nafion112 membrane was placed between the anode and the cathode, and after hot pressing at 137°C and 5 MPa pressure for 120 seconds, it was taken out and cooled to room temperature to obtain the "membrane electrode" assembly of the fuel cell. The "membrane electrode" assembly was then loaded into a fuel cell fixture for evaluation. Using pure hydrogen as fuel and pure oxygen as oxidant, the battery test temperature is 80°C, the positive and negative electrode back pressures are both 200 kPa (absolute pressure), the negative electrode hydrogen flow rate is 180-200 ml/min, and the positive electrode _O2 flow rate is 200-300 ml/min minute.

The polarization curve of the single cell was tested under constant potential conditions, and the variation of the potential with the current density was recorded, corresponding to curve 2 in Figure 5. The variation of recording power density with current density corresponds to curve 1 in Fig. 5 .

Example 2

An oxygen-reducing non-noble metal catalyst and a preparation method thereof, the specific method steps comprising:

(1) Preparation of kaolin suspension for pyrrole intercalation

It is 1: 4 to weigh kaolin and pyrrole by kaolin: the mass ratio of pyrrole, first kaolin is dispersed in deionized water, and ultrasonic stirring 8 hours forms the kaolin suspension that mass concentration is 0.1 g/ml; Press kaolin suspension: acetone Acetone was measured at a volume ratio of 1:1, pyrrole was dissolved in acetone, and added to the above kaolin suspension, stirred at 60°C for 10 hours to form a pyrrole-intercalated kaolin suspension.

(2) Interlayer polymerization of pyrrole

The kaolin suspension of pyrrole intercalation obtained by step (1): the volume ratio of hydrochloric acid solution 1: 0.5 measures hydrochloric acid solution, wherein the concentration of hydrochloric acid solution is 0.5 mole/liter; by pyrrole: the mass ratio of hydrogen peroxide is 1: 2 Weigh hydrogen peroxide, and dissolve it in deionized water to form a hydrogen peroxide solution with a mass concentration of 1 g/ml; first add the hydrochloric acid solution to the pyrrole-intercalated kaolin suspension obtained in step (1), stir for 3 hours, and then add the hydrogen peroxide The solution was added to the above suspension at a speed of 1 ml/min, stirred and reacted at 10°C for 30 hours, finally vacuum filtered, washed with deionized water and absolute ethanol for 3 times, dried at 60°C for 24 hours, and kaolin was obtained after grinding Interlayer polypyrrole.

(3) Preparation of nitrogen-doped graphene-like catalyst

The kaolin interlayer polypyrrole obtained in step (2) is placed in a tube furnace, and after 0.5 hours of passing argon gas into the tube furnace with a flow rate of 200 ml/min, the argon flow rate is maintained and the temperature is raised at 20° C./min. Speed, first raise the tube furnace to 180°C for 4 hours, then continue to heat up to 1000°C for 1 hour, cool to room temperature, and grind to obtain kaolin interlayer nitrogen-doped graphene; according to the mass ratio of kaolin: hydrofluoric acid Weigh hydrofluoric acid at 1:2, wherein the mass concentration of hydrofluoric acid is 40%; first disperse the above-mentioned kaolin interlayer nitrogen-doped graphene in ethanol, and ultrasonically stir for 8 hours to form a kaolin interlayer with a mass concentration of 1 g/ml Nitrogen-doped graphene-like suspension, hydrofluoric acid is slowly added to the above-mentioned kaolin interlayer nitrogen-doped graphene-like suspension, ultrasonically stirred for 20 hours, finally filtered, washed with deionized water for 3 times and absolute ethanol for 3 times Once, dry at 60°C for 24 hours, and grind to obtain a nitrogen-doped graphene-like catalyst.

(4) Stability test of nitrogen-doped graphene-like catalyst

Weigh 2 mg of the nitrogen-doped graphene-like catalyst prepared in step (3) and add it to 200 microliters of absolute ethanol solution and ultrasonically oscillate for 10 minutes to disperse evenly. After drying at 60°C on the rotating disc electrode, pipette 5 microliters of 0.05% Nafion solution and drop it on the catalytic layer, and keep it at 60°C for 2 hours. Using this electrode as the working electrode, the platinum ring electrode and the silver/silver chloride electrode (Ag/AgCl) electrode as the auxiliary electrode and the reference electrode, respectively, the cyclic voltammetry curve was tested in a sulfuric acid solution saturated with nitrogen at 0.5 mol/L. The scanning rate is 50mV/s, the scanning range is -0.2～0.8V (vs.Ag/AgCl), and a total of 800 cycles are scanned. The test results are shown in curves 1-2 in Figure 2.

Example 3

An oxygen-reducing non-noble metal catalyst and a preparation method thereof, the specific method steps comprising:

(1) Preparation of hydrotalcite suspension for aniline intercalation

Weigh hydrotalcite and aniline according to the mass ratio of hydrotalcite: aniline of 1:0.1, first disperse the hydrotalcite in deionized water, and stir ultrasonically for 3 hours to form a hydrotalcite suspension with a mass concentration of 0.01 g/ml; The volume ratio of liquid: acetonitrile is 1:0.3. Measure acetonitrile, dissolve aniline in acetonitrile, and add it to the above hydrotalcite suspension, stir at 10°C for 40 hours to form an aniline-intercalated hydrotalcite suspension.

(2) Interlayer polymerization of aniline

The hydrotalcite suspension of the aniline intercalation obtained by step (1): the volume ratio of sulfuric acid solution 1: 0.1 measures sulfuric acid solution, wherein the concentration of sulfuric acid solution is 1.5 mol/liter; by aniline: the mass ratio of potassium permanganate Potassium permanganate is weighed at 1:0.5, and dissolved in deionized water to form a mass concentration of 0.1 g/ml potassium permanganate solution; the sulfuric acid solution is first added to the hydrotalcite intercalated with aniline obtained in step (1) In the suspension, stir for 1 hour, then add potassium permanganate solution to the above suspension at a rate of 0.1 ml/min, stir and react at 0°C for 10 hours, and finally vacuum filter, wash with deionized water 3 times and absolute ethanol Wash 3 times, dry at 60°C for 24 hours, and grind to obtain polyaniline interlayered with hydrotalcite.

(3) Preparation of nitrogen-doped graphene-like catalyst

The hydrotalcite interlayer polyaniline obtained in step (2) is placed in a tube furnace, and after nitrogen is passed into the tube furnace with a flow rate of 50 ml/min for 1 hour, the nitrogen flow rate is maintained, and the temperature rise rate is 6° C./min. First, the tube furnace is raised to 120°C for 1 hour, and then continues to heat up to 700°C for 4 hours. After cooling to room temperature and grinding, a hydrotalcite interlayer nitrogen-doped graphene is obtained; according to the hydrotalcite: hydrofluoric acid mass Weigh hydrofluoric acid at a ratio of 1:2, wherein the mass concentration of hydrofluoric acid is 40%; first disperse the above-mentioned hydrotalcite interlayer nitrogen-doped graphene in ethanol, and ultrasonically stir for 3 hours to form a mass concentration of 0.1 g/ml Hydrotalcite interlayer nitrogen-doped graphene-like suspension, then slowly add hydrofluoric acid into the above-mentioned hydrotalcite interlayer nitrogen-doped graphene-like suspension, ultrasonically stir and react for 10 hours, finally filter, wash with deionized water for 3 times and remove Washed with water and ethanol three times, dried at 60°C for 24 hours, and ground to obtain a nitrogen-doped graphene-like catalyst.

(4) Oxygen reduction test before and after aging of nitrogen-doped graphene-like catalyst

Weigh 2 mg of the nitrogen-doped graphene-like catalyst prepared in step (3) and add it to 200 microliters of absolute ethanol solution and ultrasonically oscillate for 10 minutes to disperse evenly. After drying at 60°C on the rotating disc electrode, pipette 5 microliters of 0.05% Nafion solution and drop it on the catalytic layer, and keep it at 60°C for 2 hours. This electrode is used as the working electrode, the platinum ring electrode and the silver/silver chloride electrode (Ag/AgCl) electrode are used as the auxiliary electrode and the reference electrode respectively, and the oxygen reduction linearity before aging is tested in a sulfuric acid solution saturated with oxygen at 0.5mol/L. Scan curve. The scan rate is 2mV/s, and the scan range is 0.9-0V (vs.Ag/AgCl). The test results are shown in curve 1 in Figure 3. After cyclic voltammetric aging of the electrode for 800 cycles in a nitrogen-saturated 0.5mol/L sulfuric acid solution, the oxygen reduction linear scan curve after aging was tested again in an oxygen-saturated 0.5mol/L sulfuric acid solution. The test structure is shown in Figure 3 Curve 2 shows.

Example 4

An oxygen-reducing non-noble metal catalyst and a preparation method thereof, the specific method steps comprising:

(1) Preparation of brucite suspension for pyrrole intercalation

According to brucite: the mass ratio of pyrrole is 1: 3 to take brucite and pyrrole, first brucite is dispersed in deionized water, and ultrasonic stirring is formed for 6 hours to form a mass concentration of brucite suspension of 0.8 g/ml; The volume ratio of brucite suspension: ethanol is 1:0.6. Measure ethanol, dissolve pyrrole in ethanol, and add it to the above-mentioned brucite suspension, stir at 35°C for 25 hours to form pyrrole-intercalated brucite suspension.

(2) Interlayer polymerization of pyrrole

The brucite suspension of pyrrole intercalation obtained by step (1): the volume ratio of hydrochloric acid solution 1: 0.4 measures hydrochloric acid solution, wherein the concentration of hydrochloric acid solution is 0.8 mole/liter; by pyrrole: the mass ratio of ferric chloride Ferric chloride is weighed as 1: 1.5, and dissolved in deionized water to form a mass concentration of 0.8 g/ml ferric chloride solution; first the hydrochloric acid solution is added to the pyrrole-intercalated brucite suspension obtained in step (1) solution, stirred for 2.5 hours, then ferric chloride solution was added to the above suspension at a rate of 0.6 ml/min, stirred and reacted at 8°C for 25 hours, and finally vacuum filtered, washed with deionized water for 3 times and absolute ethanol for 3 times Once, dry at 60°C for 24 hours and grind to obtain brucite interlayer polypyrrole.

(3) Preparation of nitrogen-doped graphene-like catalyst

The brucite interlayer polypyrrole obtained in step (2) is placed in a tube furnace, and after 0.8 hours of passing argon gas into the tube furnace with a flow rate of 120 ml/min, the argon flow rate is maintained at 15° C./min. Minute heating rate, first raise the tube furnace to 150°C for 2 hours, then continue to heat up to 800°C for 2 hours, cool to room temperature, and grind to obtain brucite interlayer nitrogen-doped graphene; according to brucite : Hydrofluoric acid mass ratio 1: 2 takes hydrofluoric acid, wherein hydrofluoric acid mass concentration is 40%; First above-mentioned brucite interlayer nitrogen-doped graphene is dispersed in ethanol, and ultrasonic stirring forms mass concentration in 5 hours 0.6 g/ml brucite interlayer nitrogen-doped graphene-like suspension, then hydrofluoric acid is slowly added to the above-mentioned brucite interlayer nitrogen-doped graphene-like suspension, ultrasonically stirred for 12 hours, and finally filtered, Washing with deionized water for 3 times and absolute ethanol for 3 times, drying at 60°C for 24 hours, and grinding to obtain a nitrogen-doped graphene-like catalyst.

The prepared nitrogen-doped graphene-like catalyst was tested with a scanning electron microscope to obtain a scanning electron microscope (SEM) photo in FIG. 4 .

Comparative Experiment

The oxygen reduction linear sweep curve test of the commercialized Pt/C (platinum mass percent 40%) catalyst of British Johnson-Matthey company is the same as step (4) in Example 1, and the oxygen reduction linear sweep curve is as shown in curve 2 among Fig. 1; The stability test is the same as step (4) in Example 2, as shown in curves 3-4 in FIG. 2 .

Test result of the present invention:

The oxygen reduction curve in Figure 1 shows that the nitrogen-doped graphene-like catalyst exhibits excellent oxygen reduction catalytic performance, and the half-wave potential of the catalytic oxygen reduction is only 50mV away from the commercial Pt/C catalyst of Jonhson-Matthey Company. As can be seen from Fig. 2, after cyclic desk scanning 800 circles, the cyclic desk curve (Fig. 2 curve 1～2) of the nitrogen-doped graphene-like catalyst prepared by the present invention does not change substantially, while British Jonhson-Matthey company The hydrogen absorption/desorption area of the commercial Pt/C catalyst (curve 3-4 in Figure 2) has been significantly reduced, which indicates that the nitrogen-doped graphene-like catalyst is significantly more stable than the commercial Pt/C catalyst. C catalyst. It can be seen from Figure 3 that the catalytic oxygen reduction activity of the nitrogen-doped graphene-like catalyst has no significant change before and after cyclic desk aging, indicating that the nitrogen-doped graphene-like catalyst has excellent catalytic oxygen reduction stability. The nitrogen-doped graphene-like catalyst in Figure 4 has a nanosheet structure similar to graphene. It can be seen from Fig. 5 that when the nitrogen-doped graphene-like catalyst is used as the cathode catalyst, the maximum power of the single cell can reach 263mW/cm ² .

Claims (6)

1. An oxygen-reducing non-noble metal catalyst and a preparation method thereof, the specific method steps comprising It is characterized by: (1) Preparation of layered compound suspensions intercalated with aniline or pyrrole Weigh the layered compound and aniline or pyrrole according to the mass ratio of layered compound: aniline or pyrrole is 1:0.1~4, first disperse the layered compound in deionized water, and stir ultrasonically for 3~8 hours to form a mass concentration of 0.01~ 0.1 g/ml layered compound suspension; measure ethanol or acetone or acetonitrile according to the volume ratio of layered compound suspension: ethanol or acetone or acetonitrile, and dissolve aniline or pyrrole in ethanol or acetone or Acetonitrile, and added to the above-mentioned layered compound suspension, stirred at 10-60°C for 10-40 hours to form a layered compound suspension intercalated with aniline or pyrrole; (2) Interlayer polymerization of aniline or pyrrole The layered compound suspension of the aniline or pyrrole intercalation obtained in step (1): the volume ratio of sulfuric acid or hydrochloric acid solution is 1: 0.1～0.5 Measure sulfuric acid or hydrochloric acid solution, wherein the concentration of sulfuric acid or hydrochloric acid solution is 0.5～1.5 moles per liter; by aniline or pyrrole: the mass ratio of oxidant is 1: 0.5～2 to take oxidant, and be dissolved in deionized water to form mass concentration and be 0.1～1 g/ml oxidant solution; Sulfuric acid or hydrochloric acid solution is added to step (1) In the layered compound suspension obtained by aniline or pyrrole intercalation, stir for 1 to 3 hours, then add the oxidizing agent solution to the suspension at a rate of 0.1 to 1 ml/min, and stir at 0 to 10°C for 10 ~ 30 hours, finally vacuum filtered, washed 3 times with deionized water and 3 times with absolute ethanol, dried at 60°C for 24 hours, and obtained layered compound interlayer polyaniline or polypyrrole after grinding; (3) Preparation of nitrogen-doped graphene-like catalyst The layered compound interlayer polyaniline or polypyrrole obtained in step (2) is placed in a tube furnace, and the inert gas is fed into the tube furnace at a flow rate of 50 to 200 ml/min for 0.5 to 1 hour, and then kept inert Gas flow rate, at a heating rate of 6-20°C/min, first raise the tube furnace to 120-180°C and keep it for 1-4 hours, then continue to heat up to 700-1000°C and keep it for 1-4 hours, cool to room temperature, and grind , obtain layered compound interlayer nitrogen-doped graphene; Press layered compound: hydrofluoric acid mass ratio 1: 2 takes hydrofluoric acid, wherein hydrofluoric acid mass concentration is 40%; First above-mentioned layered compound interlayer nitrogen Doped graphene is dispersed in ethanol, and ultrasonically stirred for 3 to 8 hours to form a layered compound interlayer nitrogen-doped graphene suspension with a mass concentration of 0.1 to 1 g/ml, and then hydrofluoric acid is slowly added to the layered compound In the interlayer nitrogen-doped graphene-like suspension, ultrasonically stirred and reacted for 10 to 20 hours, and finally filtered, washed with deionized water for 3 times and absolute ethanol for 3 times, dried at 60°C for 24 hours, and the nitrogen-doped graphene was obtained after grinding. Graphene catalyst. 2. according to a kind of oxygen-reducing non-precious metal catalyst and preparation method thereof according to claim 1, it is characterized in that described layered compound is wherein one of montmorillonite, kaolin, waterstone and brucite; The oxidant is one of ammonium persulfate, hydrogen peroxide, potassium permanganate and ferric chloride; the inert gas is one of nitrogen and argon. 3. according to a kind of oxygen-reducing non-precious metal catalyst and preparation method thereof according to claim 1, it is characterized in that the steps (1)～(3) of specific preparation method: (1) Preparation of montmorillonite suspension for aniline intercalation Weigh montmorillonite and aniline according to the mass ratio of montmorillonite: aniline of 1:1, first disperse montmorillonite in deionized water, and ultrasonically stir for 5 hours to form a montmorillonite suspension with a mass concentration of 0.05 g/ml Measure ethanol by montmorillonite suspension: the volume ratio of ethanol is 1: 0.5, dissolve aniline in ethanol, and join in the above-mentioned montmorillonite suspension, stir 30 hours at 20 ℃, form the montmorillonite intercalation of aniline desoiled suspension; (2) Interlayer polymerization of aniline The montmorillonite suspension of the aniline intercalation obtained by step (1): the volume ratio of sulfuric acid solution 1: 0.3 measures sulfuric acid solution, wherein the concentration of sulfuric acid solution is 1 mole/liter; by aniline: the mass ratio of ammonium persulfate Ammonium persulfate is weighed at 1:1, and dissolved in deionized water to form a mass concentration of 0.5 g/ml ammonium persulfate solution; the sulfuric acid solution is first added to the aniline intercalated montmorillonite suspension obtained in step (1) solution, stirred for 2 hours, then ammonium persulfate solution was added to the above suspension at a rate of 0.5 ml/min, stirred and reacted at 5°C for 20 hours, and finally vacuum filtered, washed with deionized water for 3 times and absolute ethanol for 3 times Once, dry at 60°C for 24 hours, and obtain montmorillonite interlayer polyaniline after grinding; (3) Preparation of nitrogen-doped graphene-like catalyst The montmorillonite interlayer polyaniline obtained in step (2) is placed in a tube furnace, and after 0.8 hours of nitrogen gas is passed into the tube furnace with a flow rate of 100 ml/min, the nitrogen flow rate is maintained and the temperature is raised at 10° C./min. Speed, first raise the tube furnace to 150°C for 3 hours, then continue to heat up to 900°C for 3 hours, cool to room temperature, and grind to obtain montmorillonite interlayer nitrogen-doped graphene; according to montmorillonite: hydrogen Hydrofluoric acid mass ratio 1:2 Weigh hydrofluoric acid, wherein the mass concentration of hydrofluoric acid is 40%; first disperse the above-mentioned montmorillonite interlayer nitrogen-doped graphene in ethanol, and ultrasonically stir for 5 hours to form a mass concentration of 0.5% gram/milliliter montmorillonite interlayer nitrogen-doped graphene-like suspension, then slowly add hydrofluoric acid into the above-mentioned montmorillonite interlayer nitrogen-doped graphene-like suspension, ultrasonically stir for 15 hours, and finally filter and deionize Washing with water for 3 times and absolute ethanol for 3 times, drying at 60° C. for 24 hours, and grinding to obtain a nitrogen-doped graphene-like catalyst. 4. according to a kind of oxygen reduction non-precious metal catalyst and preparation method thereof according to claim 1, it is characterized in that the steps (1)～(3) of specific preparation method: (1) Preparation of kaolin suspension for pyrrole intercalation It is 1: 4 to weigh kaolin and pyrrole by kaolin: the mass ratio of pyrrole, first kaolin is dispersed in deionized water, and ultrasonic stirring 8 hours forms the kaolin suspension that mass concentration is 0.1 g/ml; Press kaolin suspension: acetone Measure acetone at a volume ratio of 1:1, dissolve pyrrole in acetone, add it to the kaolin suspension, and stir at 60°C for 10 hours to form a kaolin suspension intercalated with pyrrole; (2) Interlayer polymerization of pyrrole The kaolin suspension of pyrrole intercalation obtained by step (1): the volume ratio of hydrochloric acid solution 1: 0.5 measures hydrochloric acid solution, wherein the concentration of hydrochloric acid solution is 0.5 mole/liter; by pyrrole: the mass ratio of hydrogen peroxide is 1: 2 Weigh hydrogen peroxide, and dissolve it in deionized water to form a hydrogen peroxide solution with a mass concentration of 1 g/ml; first add the hydrochloric acid solution to the pyrrole-intercalated kaolin suspension obtained in step (1), stir for 3 hours, and then add the hydrogen peroxide The solution was added to the above suspension at a speed of 1 ml/min, stirred and reacted at 10°C for 30 hours, finally vacuum filtered, washed with deionized water and absolute ethanol for 3 times, dried at 60°C for 24 hours, and kaolin was obtained after grinding Interlayer polypyrrole; (3) Preparation of nitrogen-doped graphene-like catalyst The kaolin interlayer polypyrrole obtained in step (2) is placed in a tube furnace, and after 0.5 hours of passing argon gas into the tube furnace with a flow rate of 200 ml/min, the argon flow rate is maintained and the temperature is raised at 20° C./min. Speed, first raise the tube furnace to 180°C for 4 hours, then continue to heat up to 1000°C for 1 hour, cool to room temperature, and grind to obtain kaolin interlayer nitrogen-doped graphene; according to the mass ratio of kaolin: hydrofluoric acid Weigh hydrofluoric acid at 1:2, wherein the mass concentration of hydrofluoric acid is 40%; first disperse the above-mentioned kaolin interlayer nitrogen-doped graphene in ethanol, and ultrasonically stir for 8 hours to form a kaolin interlayer with a mass concentration of 1 g/ml Nitrogen-doped graphene-like suspension, hydrofluoric acid is slowly added to the above-mentioned kaolin interlayer nitrogen-doped graphene-like suspension, ultrasonically stirred for 20 hours, finally filtered, washed with deionized water for 3 times and absolute ethanol for 3 times Once, dry at 60°C for 24 hours, and grind to obtain a nitrogen-doped graphene-like catalyst. 5. According to claim 1, a kind of oxygen-reducing non-noble metal catalyst and preparation method thereof, it is characterized in that the steps (1)～(3) of the specific preparation method: (1) Preparation of hydrotalcite suspension for aniline intercalation Weigh hydrotalcite and aniline according to the mass ratio of hydrotalcite: aniline of 1:0.1, first disperse the hydrotalcite in deionized water, and stir ultrasonically for 3 hours to form a hydrotalcite suspension with a mass concentration of 0.01 g/ml; The volume ratio of liquid: acetonitrile is 1: 0.3. Measure acetonitrile, dissolve aniline in acetonitrile, and add it to the above-mentioned hydrotalcite suspension, and stir at 10°C for 40 hours to form an aniline-intercalated hydrotalcite suspension; (2) Interlayer polymerization of aniline The hydrotalcite suspension of the aniline intercalation obtained by step (1): the volume ratio of sulfuric acid solution 1: 0.1 measures sulfuric acid solution, wherein the concentration of sulfuric acid solution is 1.5 mol/liter; by aniline: the mass ratio of potassium permanganate Potassium permanganate is weighed at 1:0.5, and dissolved in deionized water to form a mass concentration of 0.1 g/ml potassium permanganate solution; the sulfuric acid solution is first added to the hydrotalcite intercalated with aniline obtained in step (1) In the suspension, stir for 1 hour, then add potassium permanganate solution to the above suspension at a rate of 0.1 ml/min, stir and react at 0°C for 10 hours, and finally vacuum filter, wash with deionized water 3 times and absolute ethanol Wash 3 times, dry at 60°C for 24 hours, and obtain hydrotalcite interlayer polyaniline after grinding; (3) Preparation of nitrogen-doped graphene-like catalyst The hydrotalcite interlayer polyaniline obtained in step (2) is placed in a tube furnace, and after nitrogen is passed into the tube furnace with a flow rate of 50 ml/min for 1 hour, the nitrogen flow rate is maintained, and the temperature rise rate is 6° C./min. First, the tube furnace is raised to 120°C for 1 hour, and then continues to heat up to 700°C for 4 hours. After cooling to room temperature and grinding, a hydrotalcite interlayer nitrogen-doped graphene is obtained; according to the hydrotalcite: hydrofluoric acid mass Weigh hydrofluoric acid at a ratio of 1:2, wherein the mass concentration of hydrofluoric acid is 40%; first disperse the above-mentioned hydrotalcite interlayer nitrogen-doped graphene in ethanol, and ultrasonically stir for 3 hours to form a mass concentration of 0.1 g/ml Hydrotalcite interlayer nitrogen-doped graphene-like suspension, then slowly add hydrofluoric acid into the above-mentioned hydrotalcite interlayer nitrogen-doped graphene-like suspension, ultrasonically stir and react for 10 hours, finally filter, wash with deionized water for 3 times and remove Washed with water and ethanol three times, dried at 60°C for 24 hours, and ground to obtain a nitrogen-doped graphene-like catalyst. 6. According to claim 1, a kind of oxygen-reducing non-noble metal catalyst and preparation method thereof, it is characterized in that the steps (1)～(3) of the specific preparation method: (1) Preparation of brucite suspension for pyrrole intercalation According to brucite: the mass ratio of pyrrole is 1: 3 to take brucite and pyrrole, first brucite is dispersed in deionized water, and ultrasonic stirring is formed for 6 hours to form a mass concentration of brucite suspension of 0.8 g/ml; The volume ratio of brucite suspension: ethanol is 1:0.6. Measure ethanol, dissolve pyrrole in ethanol, and add it to the above-mentioned brucite suspension, stir at 35°C for 25 hours to form pyrrole-intercalated brucite suspension; (2) Interlayer polymerization of pyrrole The brucite suspension of pyrrole intercalation obtained by step (1): the volume ratio of hydrochloric acid solution 1: 0.4 measures hydrochloric acid solution, wherein the concentration of hydrochloric acid solution is 0.8 mole/liter; by pyrrole: the mass ratio of ferric chloride Ferric chloride is weighed as 1: 1.5, and dissolved in deionized water to form a mass concentration of 0.8 g/ml ferric chloride solution; first the hydrochloric acid solution is added to the pyrrole-intercalated brucite suspension obtained in step (1) solution, stirred for 2.5 hours, then ferric chloride solution was added to the above suspension at a rate of 0.6 ml/min, stirred and reacted at 8°C for 25 hours, and finally vacuum filtered, washed with deionized water for 3 times and absolute ethanol for 3 times times, dry at 60°C for 24 hours, and obtain brucite interlayer polypyrrole after grinding; (3) Preparation of nitrogen-doped graphene-like catalyst The brucite interlayer polypyrrole obtained in step (2) is placed in a tube furnace, and after 0.8 hours of passing argon gas into the tube furnace with a flow rate of 120 ml/min, the argon flow rate is maintained at 15° C./min. Minute heating rate, first raise the tube furnace to 150°C for 2 hours, then continue to heat up to 800°C for 2 hours, cool to room temperature, and grind to obtain brucite interlayer nitrogen-doped graphene; according to brucite : Hydrofluoric acid mass ratio 1: 2 takes hydrofluoric acid, wherein hydrofluoric acid mass concentration is 40%; First above-mentioned brucite interlayer nitrogen-doped graphene is dispersed in ethanol, and ultrasonic stirring forms mass concentration in 5 hours 0.6 g/ml brucite interlayer nitrogen-doped graphene-like suspension, then hydrofluoric acid is slowly added to the above-mentioned brucite interlayer nitrogen-doped graphene-like suspension, ultrasonically stirred for 12 hours, and finally filtered, Washing with deionized water for 3 times and absolute ethanol for 3 times, drying at 60°C for 24 hours, and grinding to obtain a nitrogen-doped graphene-like catalyst.

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