CN113497237B

CN113497237B - Synthesis method and application of copper polyphenol-triazine supermolecular network structure nano composite material

Info

Publication number: CN113497237B
Application number: CN202110760693.4A
Authority: CN
Inventors: 肖高; 胡凡莹; 刘明华
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2022-04-26
Anticipated expiration: 2041-07-06
Also published as: CN113497237A

Abstract

The invention belongs to the technical field of fuel cell catalysts, and particularly relates to a synthetic method and application of a copper polyphenol-triazine supermolecular network structure nano composite material. The method comprises the following steps: weighing 1,3, 5-triazine-2, 4, 6-triamine and saturated polycyclic ketone, and reacting to obtain a covalent triazine-based organic polymer CTP; preparing CTP into a CPT-polyphenol solution; combining the copper polyphenol solution and the CPT-polyphenol solution for reaction; centrifuging and drying a product obtained by the reaction to obtain a precursor; and calcining the precursor in an inert atmosphere to prepare the copper polyphenol-triazine supermolecular network structure nano composite material. The covalent triazine-based organic polymer is used as a base material, and the nano composite material with excellent oxygen reduction performance is obtained by means of functional modification of the polyphenol network, so that the metal polyphenol network and the triazine polymer skeleton are tightly combined, and the nano composite material has the characteristics of economy, high efficiency, greenness and environmental protection.

Description

Synthesis method and application of copper polyphenol-triazine supermolecular network structure nano composite material

Technical Field

The invention belongs to the technical field of fuel cell catalysts, and particularly relates to a synthetic method and application of a copper polyphenol-triazine supermolecular network structure nano composite material.

Background

In the history development process of human society, the contradiction between energy crisis and environmental pollution is always the main driving force for the research of scientists in the world. With the gradual depletion of traditional fossil fuels, the development of clean and efficient energy storage and conversion technologies is urgent. Among the many new energy technologies, fuel cell and electrolytic water technologies are most studied as sustainable and environmentally friendly energy conversion technologies. Currently, the main problem of fuel cells is cathode electrocatalyst, where cathode Oxygen Reduction Reaction (ORR) kinetics are retarded, so more catalyst is needed to accelerate the Oxygen Reduction Reaction. The best cathode electrocatalyst on the market is platinum catalyst, however, platinum is expensive, has limited reserves and is easy to be poisoned, so that the application of large-scale commercialization of fuel cells is limited, and the development of non-noble metal ORR catalyst with low cost, abundant resources, high activity and durability is urgently needed, which has important significance.

For example, patent document No. CN 107112546B discloses a method for manufacturing a cathode catalyst layer for a fuel cell. The method comprises the following steps:

carrying out heat treatment on the ordered mesoporous carbon containing hydrophilic groups to enable the ordered mesoporous carbon to be subjected to surface modification, wherein the surface of the heat-treated ordered mesoporous carbon has hydrophobicity;

dispersing the heat-treated ordered mesoporous carbon, a catalyst and an ionomer in an organic solvent to form a composition;

and coating the composition on a support film and drying;

wherein the heat treatment is performed at 900 to 3000 ℃ for 30 minutes to 3 hours.

This proposal is based on the realization of commercialization of a polymer electrolyte type fuel cell, and is proposed to reduce the cost by reducing the amount of platinum used. However, if the amount of platinum is reduced, disadvantages are caused in terms of power and durability. The invention effectively solves the problems of power and durability through the technical scheme.

Covalent triazine-based organic polymers (CTPs) have the characteristics of low frame structure mass, large specific surface area, high porosity, diversified structural rigidity and the like, and are therefore deeply researched in the fields of gas adsorption, catalysis, photoelectronic devices, energy storage and the like. However, the CTPs have limited potential for practical application in the electrochemical field due to expensive raw materials and strict preparation conditions for CTPs synthesis. At present, few reports of the application of CTPs in the aspect of fuel cell cathode materials exist.

Disclosure of Invention

The invention aims to solve the problems of low activity, poor stability and the like of the existing fuel cell catalyst and provides a copper polyphenol-triazine supermolecular network structure nano composite material. The composite material prepared by the method has high potential, excellent limiting current and excellent stability, and has excellent methanol tolerance.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a synthetic method of a copper polyphenol-triazine supermolecular network structure nano composite material comprises the following steps:

1) weighing 1,3, 5-triazine-2, 4, 6-triamine and saturated polycyclic ketone, reacting under ultrasound, centrifuging to obtain a product, washing the product with volatile alcohol, ether or ester solvent, centrifuging, and drying in vacuum to obtain a covalent triazine-based organic polymer CTP;

2) dispersing the CTP in a plant polyphenol solution, and performing ultrasonic dispersion treatment to prepare a CPT-polyphenol solution;

3) dispersing soluble copper salt in a plant polyphenol solution, and performing ultrasonic dispersion treatment to prepare a copper polyphenol solution; combining the copper polyphenol solution and the CPT-polyphenol solution to react;

4) filtering out the product obtained in the step 3), washing with deionized water and volatile alcohol, ether or ester solvent respectively, centrifuging and drying to obtain CTP @ Cu²⁺-a PP precursor;

5) converting the CTP @ Cu²⁺And (3) calcining the PP precursor in an inert atmosphere to prepare the copper polyphenol-triazine supermolecular network structure nano composite material CTP @ Cu-PP.

In the technical scheme of the invention, the specific synergistic effect of the polyphenol-triazine network is utilized to construct a large-specific-area and rich pore structure on the nano composite material, so that the accumulation of active ingredients is effectively prevented, and the density of catalytic active sites is improved, thereby obtaining the electro-catalytic material with high-efficiency electro-catalytic performance on the ORR electrochemical process.

The plant polyphenol has abundant phenolic hydroxyl structures, can form a stable structure with metal ions, and can be combined with a polymer substrate, so that the active sites of the material can be increased, and the accumulation of active components can be avoided.

The free hydrogen ions released by the plant polyphenols can penetrate into the polymer substrate and destroy the internal skeleton, while the plant polyphenol macromolecules coat the exposed surface of the material, thus protecting its exterior from further etching and collapse of the shell.

According to the invention, the porous structure is elaborately carved by regulating the concentration and the reaction time of the plant polyphenol, so that the CTP @ Cu-PP presents a uniform granular appearance to form a layered porous structure, thereby facilitating the permeation of electrolyte and improving the oxygen reduction catalytic performance of the material.

Preferably, in the step 1), the molar ratio of the 1,3, 5-triazine-2, 4, 6-triamine to the saturated polycyclic ketone is (2-4): 1, and the solvent used for the ultrasonic dispersion treatment is one or more selected from ethanol, propanol, acetic acid and methanol.

Preferably, the plant polyphenol is selected from one or more of acorn tannin, myricetin or larch tannin; the concentration of the plant polyphenol solution is 8-16 mmol/L.

Preferably, in the step 5), the calcination comprises two temperature sections based on time, wherein the temperature of the first temperature section is controlled to be 200-500 ℃, and the temperature of the second temperature section is controlled to be 600-1000 ℃; the residence time of the first temperature section is 1-3 h, and the residence time of the second temperature section is 1-3 h.

Preferably, in the step 1), the ultrasonic temperature is 40-60 ℃ and the ultrasonic time is 1.5-2 h.

Preferably, in the step 1), the vacuum drying is performed at 60-80 ℃ for 8-16 h in a vacuum atmosphere.

Preferably, in the step 2), an ultrasonic instrument and a magnetic stirring device are adopted for ultrasonic dispersion treatment, the temperature is set to be normal temperature, the ultrasonic time is 10-20 min, and the stirring time is 1-2 h.

Preferably, in the step 4), the drying temperature is 60-80 ℃.

Preferably, the temperature rise rate of the first temperature section is 5-10 ℃/min, and the temperature rise rate of the second temperature section is 5-10 ℃/min.

The invention also aims to provide application of the composite material prepared by the synthesis method in fuel cells.

In particular to application of the copper polyphenol-triazine supermolecular network structure nano composite material prepared by the synthesis method in the aspect of fuel cell cathode materials.

In conclusion, the invention has the following beneficial effects:

1) the covalent triazine-based organic polymer is used as a base material, and the nano composite material with excellent oxygen reduction performance is obtained by means of functional modification of the polyphenol network, so that the metal polyphenol network and the triazine polymer skeleton are tightly combined, and the nano composite material has the characteristics of economy, high efficiency, greenness and environmental protection. The synthesis steps are simple and convenient to operate, the reaction conditions are mild and easy to control, and the preparation cost is low.

2) The invention utilizes the unique synergistic effect of the polyphenol-triazine network to construct a large specific surface area and a rich pore structure on the nano composite material, effectively prevents the accumulation of active ingredients, and improves the density of catalytic active sites, thereby obtaining the electro-catalytic material with high-efficiency electro-catalytic performance for the ORR electrochemical process.

3) The invention also designs and synthesizes a series of catalyst materials calcined at different Cu loading amounts and different temperatures by regulating and controlling the heat treatment temperature and the metal loading amount. Electrochemical test studies showed that the limiting current density of the CTP @ Cu-PP catalyst in 0.1M KOH at a potential equal to 0.1V was that of a commercial Pt/C catalyst (J_d=5.13 mA cm^-2) 1.28 times of; meanwhile, the reaction history of ORR in alkaline medium is 4 electron dominant, and in addition, has more excellent electrochemical stability and methanol tolerance than commercial Pt/C catalyst.

4) The composite material prepared by the method can be used as a cathode material of a proton membrane fuel cell, and the active component is CTP @ Cu-PP. Cu in the material exists in an atomic form and is tightly combined with a polyphenol-triazine network structure, so that the oxygen reduction catalytic active sites of the material are effectively increased. The material presents a uniform granular structure, has rich pore channel structures inside, increases the specific surface area of the material, and simultaneously exposes rich active sites, thereby promoting the permeation of electrolyte. Therefore, the material shows good oxygen reduction electrocatalytic performance, has high potential and excellent limiting current, and has excellent stability and methanol tolerance.

Drawings

FIG. 1 is a scanning electron microscope image of CTP @ Cu-PP nanocomposite;

FIG. 2 is CTP and CTP @ Cu²⁺-infrared spectrogram of PP precursor;

FIG. 3 is an XRD pattern of CTP and CTP @ Cu-PP nanocomposite (scan interval: 5 ° -80 °, step size: 0.02 °, scan rate: 1.5 °/min);

FIG. 4 is a plot of CTP @ Cu-PP at O for various Cu loadings (40, 50, 60, 70, 80 mg)₂Linear cyclic voltammograms in saturated 0.1M KOH (scan range-0.9-0.1V, scan rate 10 mv/s);

FIG. 5 is a linear cyclic voltammogram of CTP @ Cu-PP catalyst at different heat treatment temperatures (600, 700, 800, 900 deg.C) (test voltage range: -0.9-0.1V, scan speed: 50 mV/s), respectively;

FIG. 6 is a plot of the cyclic voltammetry characteristics of the CTP @ Cu-PP catalyst (test voltage sweep range: -0.9-0.1V, sweep rate: 50 mV/s);

FIG. 7 is a linear cyclic voltammogram of commercial Pt/C (20 wt% Pt) catalysts, CTP and CTP @ Cu-PP catalysts (test voltage range: -0.9-0.1V, scan speed: 50 mV/s);

FIG. 8 is a linear cyclic voltammogram (scan rate: 10 mV/s) of the CTP @ Cu-PP catalyst at different rpm (400, 625, 900, 1225, 1600, 2025 rmp);

FIG. 9 is a K-L curve for a CTP @ Cu-PP catalyst;

FIG. 10 is a graph of stability measurements of CTP @ Cu-PP catalyst and commercial Pt/C (20 wt% Pt) catalyst by potentiostatic amperometry;

FIG. 11 is a graph of methanol tolerance tests of CTP @ Cu-PP catalyst and commercial Pt/C (20 wt% Pt) catalyst by potentiostatic amperometry.

Detailed Description

The embodiment provides a synthesis method of a copper polyphenol-triazine supermolecular network structure nano composite material, namely a method for preparing a CTP @ Cu-PP catalyst. The method comprises the following steps:

1) weighing 1,3, 5-triazine-2, 4, 6-triamine and 1,3, 5-cyclohexanetrione according to a molar ratio of 3:1, dispersing in methanol, performing ultrasonic treatment at 40 ℃ for 1.5 h, washing the obtained product with ethanol for several times, centrifuging, and performing vacuum drying at 60 ℃ for 15 h to obtain a covalent triazine-based organic polymer CTP;

2) dispersing 0.3 g of CTP prepared in the step 1) in 30 ml of plant polyphenol solution (12 mmol/L), and carrying out ultrasonic treatment at room temperature for 20 min;

3) dispersing 60 mg of copper sulfate pentahydrate in 30 ml of plant polyphenol solution (12 mmol/L), carrying out ultrasonic treatment at room temperature for 10 min, pouring the ultrasonic treated solution into the ultrasonic CTP solution obtained in the step 2), and stirring and reacting at room temperature for 1 h;

4) washing the product obtained in the step 3) with deionized water and ethanol solution, centrifuging, and drying the product in an oven at 60 ℃ for 12 h to obtain CTP @ Cu²⁺-a PP precursor;

5) uniformly dispersing a proper amount of dried precursor at the bottom of the porcelain ark, putting the porcelain ark in a tube furnace for high-temperature pyrolysis in an argon atmosphere, directly heating to 350 ℃ at a heating rate of 5 ℃/min in a pure argon atmosphere, keeping the temperature for 2 hours, heating to 800 ℃ at the same heating rate, keeping the temperature for 2 hours, and naturally cooling to room temperature to obtain the copper polyphenol-triazine supermolecular network structure nano composite material CTP @ Cu-PP.

Phase identification and micro morphology and structure characterization of the CTP @ Cu-PP material obtained in the embodiment are as follows: and performing phase identification on the prepared material by using a Raman spectrometer, a Fourier transform infrared spectrometer and a powder X-ray diffractometer, and performing micro-morphology and structure characterization on the obtained material by using a scanning electron microscope.

FIG. 1 is a scanning electron microscope image of CTP @ Cu-PP nanocomposite. As can be seen from the figure, the material presents a uniform granular structure, the particle size distribution is about 100 nm, the size is uniform, and the surface has a rich pore structure. This indicates that free H released from plant polyphenols penetrates into CTP and etches it, thereby forming a porous structure inside it to expose more active sites.

FIG. 2 is CTP and CTP @ Cu²⁺-infrared spectrum of PP precursor. As can be seen from the figure, the temperature at 3300-^-1The broad peak in the range corresponds to the stretching vibration characteristic peak of the N-H bond in imine, 1020 and 1350 cm^-1The characteristic peak in the range is caused by stretching vibration of C-N bond in imine by 1640 cm^-1The absorption peak signal at (B) represents the stretching vibration of C = N key at 810 cm^-1The sum of characteristic peaks at (D) and (D) 1370-1520 cm^-1Characteristic peaks within the range belong to the out-of-plane ring vibration and the in-plane ring vibration of the C = N bond in the triazine ring, respectively. Compared with CTP and CTP @ Cu²⁺The position of the absorption peak of the PP precursor is basically unchanged and slightly shifts, which shows that the original structure of the precursor is not damaged by polyphenol modification and Cu doping, and the metal polyphenol network is well combined with CTP.

FIG. 3 is an XRD pattern of CTP and CTP @ Cu-PP nanocomposite. As can be seen from the figure, a broader diffraction peak is generated at 2 θ = 26.5 °, corresponding to the characteristic peak of graphitic carbon, indicating that the material has good graphitization degree after heat treatment. CTP @ Cu-PP shows strong diffraction peaks at 2 θ =43.3 °, 50.5 ° and 74.1 °, corresponding to the (111), (200) and (220) crystal planes of metallic Cu, respectively. Illustrating Cu carried on the material after heat treatment²⁺Is reduced into a Cu simple substance, and the Cu atom increases the catalytic active site of the material, so that the oxygen reduction catalytic performance of the CTP @ Cu-PP is obviously improved.

The embodiment provides a method for synthesizing a copper polyphenol-triazine supermolecular network structure nano composite material and an oxygen reduction catalyst using the material.

The active substance described in this example, abbreviated as CTP @ Cu-PP, exhibits a uniform particulate structure.

In this example, a carbon rod was used as a counter electrode, a saturated silver chloride electrode (Ag/AgCl) was used as a reference electrode, and a glassy carbon electrode was used as a working electrode.

The concentration of Nafion added in the preparation process of the catalyst described in this example was 5%, and the amount used was 15 ul.

In the test process of the embodiment, the pretreatment of the electrode is to add alpha-Al on a nylon polishing cloth base₂O₃Polishing the rotating disc electrode for 10 min in an 8-shaped manner by using electrode polishing powder and a small amount of deionized water, cleaning residual powder on the electrode by using the deionized water, and finally naturally drying to finish the treatment.

The catalyst described in this example was prepared by dispersing 4 mg of the catalyst in a 1 mL centrifuge tube using a balance, adding 250 uL of deionized water, 735 uL of isopropanol and 15 uL of 5 wt% Nafion solution, and then sonicating for 50 minutes to obtain the catalyst ink (ink). Then gradually dropping 28 uL ink on the surface of the glassy carbon electrode (catalyst loading amount is 0.25 mg cm)^-2) And carrying out an electrocatalysis performance test after naturally drying.

All electrocatalytic performance tests described in this example were performed in 0.1M KOH (pH =13.62) electrolyte and the experimentally measured potential was converted to a potential relative to a Reversible Hydrogen Electrode (RHE) by the following equation:

the potential values referred to in this example are all potentials relative to the reversible hydrogen electrode.

The catalyst described in this example requires CV activation for 3 cycles before electrochemical testing.

The catalyst described in this example is tested at normal temperature, and the influence of large temperature variation difference on the performance of the catalyst is prevented.

Nafion added during the catalyst preparation described in this example was manufactured by Aldrich sigma and had a concentration of 5%.

The catalyst is absorbed by a pipette gun to be 7 ul and dropped on a working electrode, the step is repeated for 3 times after the catalyst is naturally dried, then the working electrode is slowly immersed into 0.1M KOH electrolyte saturated by oxygen, bubbles are prevented from being generated on the working electrode in the step, and the electrolyte is continuously introduced into oxygen in the whole testing process to ensure oxygen saturation.

Cyclic voltammetry and linear cyclic voltammetry tests were performed on the catalyst obtained in this example: the cyclic voltammetry test was carried out using an electrochemical workstation manufactured by Pine of the United states, the test voltage sweep range was-0.9-0.1V, the sweep rate was 50 mV/s, and during the test, the cyclic voltammetry test was carried out after 3 cycles of activation with a current density of 50 mV/s. Linear cyclic voltammetry tests were also performed using the Pine electrochemical workstation, with a test voltage sweep range of-0.9-0.1V and a sweep rate of 50 mV/s. The current density of the catalyst material under different rotating speeds can be obtained through rotating speed test, the number of transferred electrons can be obtained by utilizing a K-L equation, the test current density is 10 mV/s, and the rotating speeds are 625 rmp, 900 rmp, 1225 rmp, 1600 rmp and 2025 rmp. The stability and the methanol tolerance are also important indexes of the catalyst performance, the test is also completed on an electrochemical workstation, the stability test voltage is-0.189V, and the test time length is 20000 s; the methanol tolerance test voltage was-0.189V, the test duration was 1000 s, and a 3M methanol solution was dropped at 300 s.

FIG. 4 is a plot of CTP @ Cu-PP at O for various Cu loadings (40, 50, 60, 70, 80 mg)₂The linear cyclic voltammogram in saturated 0.1M KOH (the scanning range is-0.9-0.1V, the scanning speed is 10 mv/s), and according to the chart, the oxygen reduction catalytic performance of the nano composite material is obviously improved along with the increase of Cu loading under the heat treatment temperature of 800 ℃, and the limiting current density is 5.77 mA cm²Increased to 6.55 mA cm²The ORR performance of the material reached the optimum at a loading of 60 mg, after which the oxygen reduction performance of the material began to decline as the Cu loading increased.

FIG. 5 is a linear cyclic voltammogram of the CTP @ Cu-PP catalyst at different heat treatment temperatures (600, 700, 800, 900 deg.C) (test voltage range: -0.9-0.1V, scanning speed: 50 mV/s), as shown in the figure, the half-wave potential and the limiting current density become better gradually with the increase of the initial potential of the nanocomposite material, but the initial potential and the half-wave potential of the CTP @ Cu-PP are further optimized but the limiting current density is decreased when the calcination temperature reaches 900 deg.C. This indicates that the CTP @ Cu-PP catalyst performs optimally when the heat treatment temperature is 800 ℃.

FIG. 6 is a plot of cyclic voltammetry characteristics (test voltage sweep range: -0.9-0.1V, sweep rate: 50 mV/s) for CTP @ Cu-PP catalyst at O₂In the saturated electrolyte, there is a distinct cathodic oxygen reduction peak at 0.73V, indicating that a catalytic oxygen reduction reaction has taken place, whereas in N₂No obvious oxygen reduction peak appears under saturated conditions, and the response to oxygen shows that CTP @ Cu-PP has obvious oxygen reduction catalytic activity in alkaline solution.

FIG. 7 is a linear cyclic voltammogram of commercial Pt/C (20 wt% Pt) catalysts, CTP and CTP @ Cu-PP catalysts (test voltage range: -0.9-0.1V, scanning speed: 50 mV/s), from which it can be seen that CTP @ Cu-PP modified by polyphenol and Cu doping has greatly improved initial potential, half-wave potential and limiting current density compared with CTP, which indicates that the metal polyphenol network provides more active sites and effectively improves the oxygen reduction catalytic performance of the material. Although the onset potential and half-wave potential of CTP @ Cu-PP are slightly behind compared to commercial Pt/C catalysts, the limiting current density exhibits great advantage.

FIG. 8 is a linear cyclic voltammogram (scan rate: 10 mV/s) of CTP @ Cu-PP catalyst at different rotation speeds (400, 625, 900, 1225, 1600, 2025 rmp), and it can be seen that the limiting diffusion current density of the catalyst gradually increases with increasing rotation speed, since the faster the rotation speed, the faster the diffusion rate of oxygen, indicating that the oxygen reduction catalytic process is mass transfer controlled.

FIG. 9 is a K-L curve of a CTP @ Cu-PP catalyst, and by linear fitting of the corresponding current density and rotation speed at different voltages, it can be seen that the slope of the curve remains substantially constant over the whole scanning potential range, which means that oxygen reduction under the action of the catalyst has the same number of transferred electrons at different potentials. The ORR electron transfer number (n) of the catalyst CTP @ Cu-PP in the potential range of 0.2V to 0.4V is calculated to be 3.99 according to the RRDE test results, which proves that the oxygen reduction catalytic process of the CTP @ Cu-PP catalyst belongs to a four-electron transfer process in an alkaline electrolyte.

FIG. 10 is a graph of stability measurements of CTP @ Cu-PP catalyst and commercial Pt/C (20 wt% Pt) catalyst by potentiostatic amperometry. It can be seen that the current density retention of CTP @ Cu-PP after 20000 s test period is about 88%, and the current density retention of Pt/C catalyst under the same condition is only 78%, which indicates that the CTP @ Cu-PP catalyst has good stability beyond that of Pt/C catalyst.

FIG. 11 is a graph of methanol tolerance tests of CTP @ Cu-PP catalyst and commercial Pt/C (20 wt% Pt) catalyst by potentiostatic amperometry. As shown in the figure, after 3 ml of methanol is added into the electrolyte at 300 s, the current density of the CTP @ Cu-PP catalyst fluctuates in a small range and then tends to be stable, and the current density of the Pt/C catalyst immediately shows a trend of greatly decreasing after the methanol is added, so that the result shows that the CTP @ Cu-PP catalyst has better methanol tolerance and can keep stable oxygen reduction catalytic activity in a more complex electrolyte environment compared with the Pt/C catalyst.

Claims

1. A synthetic method of a copper polyphenol-triazine supermolecular network structure nano composite material comprises the following steps:

5) converting the CTP @ Cu²⁺Calcining the PP precursor in an inert atmosphere to prepare a copper polyphenol-triazine supermolecular network structure nano composite material CTP @ Cu-PP;

in the step 5), the calcination comprises two temperature sections based on time, wherein the temperature of the first temperature section is controlled to be 200-500 ℃, and the temperature of the second temperature section is controlled to be 600-1000 ℃; the residence time of the first temperature section is 1-3 h, and the residence time of the second temperature section is 1-3 h.

2. The method for synthesizing the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 1, wherein the method comprises the following steps: in the step 1), the molar ratio of the 1,3, 5-triazine-2, 4, 6-triamine to the saturated polycyclic ketone is (2-4): 1, and the solvent used for ultrasonic dispersion treatment is one or more selected from ethanol, propanol, acetic acid and methanol.

3. The method for synthesizing the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 1, wherein the method comprises the following steps: the plant polyphenol is one or more selected from acorn tannin, myricetin or larch tannin; the concentration of the plant polyphenol solution is 8-16 mmol/L.

4. The method for synthesizing the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 1, wherein the method comprises the following steps: in the step 1), the ultrasonic temperature is 40-60 ℃, and the ultrasonic time is 1.5-2 h.

5. The ultrasonic synthesis method of the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 1, wherein the ultrasonic synthesis method comprises the following steps: in the step 1), the vacuum drying is drying for 8-16 h at 60-80 ℃ in a vacuum atmosphere.

6. The method for synthesizing the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 1, wherein the method comprises the following steps: in the step 2), an ultrasonic instrument and a magnetic stirring device are adopted for ultrasonic dispersion treatment, the temperature is set to be normal temperature, the ultrasonic time is 10-20 min, and the stirring time is 1-2 h.

7. The method for synthesizing the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 1, wherein the method comprises the following steps: in the step 4), the drying temperature is 60-80 ℃.

8. The method for synthesizing the copper polyphenol-triazine supermolecular network structure nanocomposite material according to claim 4, wherein the method comprises the following steps: the temperature rise rate of the first temperature section is 5-10 ℃/min, and the temperature rise rate of the second temperature section is 5-10 ℃/min.

9. The application of the copper polyphenol-triazine supermolecular network structure nano composite material prepared by the synthetic method of claims 1-8 in the aspect of fuel cell cathode materials.