Preparation method and application of mesoporous high-entropy alloy-based PtPdRhRuCu / cork wood derived carbon composite catalyst

Abstract

The invention discloses a preparation method and application of a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / cork wood derived carbon, and relates to a preparation method and application of a composite catalyst. The invention aims to solve the problem that during preparation of the Pt-based mesoporous high-entropy alloy, due to coexistence of various metal precursors, significant difference exists in reduction kinetics, so that nucleation and crystal growth processes are difficult to cooperatively control. According to the invention, five metal elements of Pt, Pd, Rh, Ru and Cu are ingeniously combined to form the high-entropy alloy, and the synergistic enhanced cocktail effect is generated by utilizing the unique functions (such as the high activity of Pt and Pd, the strong regulation ability of Rh and Ru on oxygen-containing species, and the Cost-down effect and electronic regulation of Cu) of each element; meanwhile, the composite material is compounded with mesoporous carbon, so that a stable conductive network and a reaction interface are constructed. The invention belongs to the technical field of electrocatalysts.

Description

Technical Field

[0001] This invention relates to a method for preparing a composite catalyst and its application, belonging to the field of electrocatalyst technology. Background Technology

[0002] In recent years, with the large-scale utilization of renewable energy and the rapid development of the electric vehicle industry, the development of next-generation electrochemical energy storage devices with high energy density, high safety, and low cost has become an urgent need in the energy sector. Against this backdrop, zinc-air batteries, due to their outstanding advantages such as high theoretical energy density, abundant raw material sources, environmental friendliness, and good safety, are considered a new energy storage system with great development potential. The oxygen reduction reaction is a key cathode reaction in clean energy conversion devices such as fuel cells and metal-air batteries. However, the slow kinetics of this reaction severely limit the overall efficiency and performance of these energy devices.

[0003] Currently, platinum-based catalysts remain the most effective oxygen reduction reaction catalysts in commercial applications. However, platinum is scarce and expensive, and prone to poisoning, migration, and Ostwald ripening in practical environments, leading to decreased catalytic activity and insufficient stability. This significantly limits the large-scale commercial application of fuel cell technology. The core advantage of Pt-based mesoporous alloy materials lies in their unique structural characteristics: high specific surface area, tunable pore structure, and efficient mass transfer and electron conduction pathways. These characteristics work together to significantly improve their activity and stability in the oxygen reduction reaction. Although preparation methods are constantly maturing, existing materials are mostly composed of two or three metals. This limited elemental combination restricts further optimization of their performance, resulting in catalytic activity and long-term durability that fail to meet the high requirements of practical applications. In other words, there is a clear structure-activity relationship between the long-term durability of catalytic materials and the chemical and structural stability of the metal components under different operating conditions. Materials are prone to failure under harsh operating conditions (such as acidic / alkaline environments, high temperatures, and high voltages), and the metal composition is the fundamental reason for this susceptibility. In recent years, high-entropy alloys, as an emerging material design concept, have provided a new direction for catalyst development. High-entropy alloys are typically composed of five or more main elements in equiatomic or near-equiatomic ratios. Their inherent high-entropy effect, lattice distortion effect, slow diffusion effect, and "cocktail" effect make them thermodynamically inclined to form a stable single solid solution phase, while kinetically exhibiting excellent structural stability and resistance to dissolution. Applying the concept of high-entropy alloys to the field of catalysis holds promise for precisely controlling the electronic structure of active sites at the atomic level through the synergistic effect between multiple elements, thereby obtaining novel catalysts with both high activity and ultra-high stability. However, high-entropy alloy nanoparticles, especially noble metal systems, are prone to agglomeration and phase separation during preparation and reaction due to their high surface energy, thus losing their high-entropy characteristics. Furthermore, the conductivity and mass transfer efficiency of nanoparticles are also key factors affecting their electrocatalytic performance. Combining high-entropy alloy nanoparticles with carbon materials with high specific surface area and high conductivity is an effective strategy to address these problems. Among them, wood-derived carbon is widely used as an oxygen electrocatalyst due to its low cost, renewability, and tunable hierarchical porous structure. Mesoporous carbon materials, due to their ordered pore structure, large specific surface area, and excellent conductivity, can not only serve as a carrier to effectively disperse and stabilize high-entropy alloy nanoparticles and prevent their aggregation, but also provide efficient channels for the transport of reactants and products, fully exposing active sites.

[0004] In the preparation of Pt-based mesoporous high-entropy alloys, the coexistence of multiple metal precursors leads to significant differences in their reduction kinetics, making it difficult to coordinate the control of nucleation and crystal growth processes. This challenge has resulted in limited successful reports of such materials under mild wet chemical synthesis routes. Therefore, developing novel and simple synthetic strategies to prepare Pt-based mesoporous high-entropy alloy catalysts for efficient oxygen reduction reactions (ORRs) is particularly urgent. Summary of the Invention

[0005] This invention addresses the problem that, in the preparation of Pt-based mesoporous high-entropy alloys, the coexistence of multiple metal precursors leads to significant differences in their reduction kinetics, making it difficult to coordinate and control the nucleation and crystal growth processes. Therefore, this invention proposes a method for preparing a composite catalyst based on the mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon composite catalyst and its application.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows: The steps of the method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon include: Step 1: Dissolve F127 in 1 mL of ultrapure water, add 40 mM K2PtCl4, Na2PdCl4, Na3RhCl6, RuCl3·xH2O, and CuCl2·2H2O and stir for 1 hour to obtain a brownish-brown solution. Add 6.0 M hydrochloric acid solution to the obtained brownish-red solution and shake. Add 0.1 M L-AA solution to the brownish solution, and treat the entire solution system in an oil bath at 100°C for 24 hours to obtain a black solution. After centrifugation and washing of the black solution, it was freeze-dried to obtain a PtPdRhRuCu mesoporous high-entropy alloy. Step 2: Place the balsa wood in a tube furnace and carbonize it at high temperature in an inert gas atmosphere. After the process is complete, grind it for one hour and then add it to ethanol. Then, PtPdRhRuCu mesoporous high-entropy alloy was added and ultrasonically treated. After filtration, it was dried in a vacuum drying oven to obtain the PtPdRhRuCu / C catalyst.

[0007] Furthermore, the dosage of F127 in step 1 is 20 mg.

[0008] Furthermore, in step 1, the amounts of K2PtCl4 and Na2PdCl4 are 0.3 mL, the amount of Na3RhCl6 is 0.5 mL, the amount of CuCl2·2H2O is 0.4 mL, and the amount of RuCl3·xH2O is 2 mL.

[0009] Furthermore, in step 1, the amount of hydrochloric acid used is 0.5 mL, and the amount of L-AA used is 2 mL.

[0010] Furthermore, in step 1, the black solution is centrifuged and washed using a centrifuge at a speed of 14,000 rpm for 5 minutes, and the centrifugation is repeated at least 5 times.

[0011] Furthermore, in step 2, the high-temperature carbonization is carried out under an argon atmosphere at 5°C for 5 minutes. -1 The temperature was increased to 900℃ at a rapid rate and held for 3 hours.

[0012] Furthermore, in step 2, 40 mg of balsamic charcoal, 10 mg of PtPdRhRuCu mesoporous high-entropy alloy, and 50 mL of ethanol are added to the ethanol.

[0013] Furthermore, in step 2, the ultrasonic treatment time for adding PtPdRhRuCu mesoporous high-entropy alloy is 1-2 hours.

[0014] Furthermore, in step 2, the temperature of the vacuum drying oven is 60℃, and the drying time is 12 hours.

[0015] The composite catalyst described in this invention is applied to the cathode oxygen reduction reaction in a standard three-electrode system, wherein the reference electrode is an Ag / AgCl electrode, the working electrode is a disk electrode loaded with an electrocatalyst, and the counter electrode is a Pt sheet.

[0016] The beneficial effects of this invention are as follows: This invention ingeniously integrates the synergistic advantages of ordered mesoporous structures and high-entropy intermetallic compounds. Its three-dimensionally ordered mesoporous channels greatly enhance the accessibility of active sites and mass transfer efficiency, thereby significantly enhancing the mass activity and surface activity of the catalyst. Simultaneously, the robust mesoporous framework effectively inhibits Ostwald ripening of nanoparticles during cycling, ensuring long-term stability. On the other hand, the high-entropy intermetallic compound, composed of five specific elements, exhibits unique atomic-level isomerism on its surface, creating continuous active sites covering multiple adsorption energies, greatly optimizing the reaction pathway and accelerating reaction kinetics. It is particularly noteworthy that when this high-entropy alloy is physically loaded onto a hierarchical porous carbon support derived from balsa wood, the latter inherits the interconnected channels and abundant functional groups of natural wood, providing not only uniform dispersion and robust anchoring points for the alloy nanoparticles, but also constructing an efficient electron transport network and electrolyte permeation pathway, further enhancing the overall atomic durability of the catalytic system. The key feature of this invention is that it not only develops a novel catalyst with both excellent oxygen reduction activity and stability, but its simple one-step synthesis strategy also shows good potential for large-scale production, while providing key theoretical insights for the design of efficient electrocatalytic materials at the atomic scale. Attached Figure Description

[0017] Figure 1These are SEM, TEM, and corresponding elemental mapping images of the mesoporous high-entropy alloy / carbon (MHEA / C) of Embodiment 1 of the present invention. Figure 2 These are the XRD patterns of Embodiment 1 and Comparative Example 1 of the present invention; Figure 3 These are the oxygen reduction catalytic performance related test curves for Example 1; Figure 3 a is the CV curve of Example 1 and Comparative Example 1 under O2 gas; Figure 3 b is a comparison graph of LSV polarization curves of Example 1, Comparative Example 1, and Comparative Example 2 at 1600 rpm; Figure 3 c is the ORR Tafel curve for Example 1, Comparative Example 1, and Comparative Example 2; Figure 3 d and Figure 3 e represents the electron transfer number and H2O2 yield in the RRDE curve of Example 1 at a rotational speed of 1600 rpm; Figure 3 f is the it curve of Example 1 after approximately 36,000 seconds; Figure 4 This is Example 1 、 Comparison curves of relevant tests of zinc-air batteries assembled with RuO2 in Comparative Example 1 and Comparative Example 2 respectively; Figure 4 a is a photo of an assembled zinc-air battery lighting an LED light, based on its charge-discharge cycle curve; Figure 4 b is a comparison chart of open-circuit voltage curves; Figure 4 c is a comparison curve of battery polarization curve and power density. Figure 4 d is a comparison of charge-discharge polarization curves; Figure 4 e is the specific capacity test curve; Figure 4 f is a comparison curve of charge and discharge rates; Figure 4 g is at a current density of 5 mA cm⁻¹ -2 The constant current cyclic charge and discharge curve at that time. Detailed Implementation

[0018] Specific implementation method one: as follows Figures 1 to 4 As shown, the steps of a method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon include: Step 1: Dissolve F127 completely in ultrapure water. The amount of F127 used is 15~30 mg. Step 2: Add K2PtCl4, Na2PdCl4, Na3RhCl6, RuCl3·xH2O, and CuCl2·2H2O to the ultrapure water in Step 1 where F127 was dissolved, and stir to obtain a brownish-yellow solution. The concentrations of K2PtCl4, Na2PdCl4, Na3RhCl6, CuCl2·2H2O, and RuCl3·xH2O are 40 mM. Step 3: Add hydrochloric acid solution to the brownish-red solution obtained in the previous step and shake gently. The concentration of hydrochloric acid is 6M. Step 4: Add L-AA solution to the brown solution in Step 3, and treat the entire solution system in an oil bath at 80~140℃ for 12~36 hours to obtain a black solution. The concentration of L-AA is 0.1 M. Step 5: Place the black solution in a centrifuge for centrifugation, washing, and freeze-drying to obtain PtPdRhRuCu mesoporous high-entropy alloy. The centrifuge speed is 12000-15000 rpm, the centrifugation time is 3-10 minutes, the number of centrifugations is more than 6, and the centrifugation solvent is acetone / ethanol. Step 6: Take an appropriate amount of balsa wood and carbonize it at high temperature in a tube furnace under an inert gas atmosphere. After the process is completed, grind it for one hour. The high-temperature carbonization is carried out under an argon atmosphere at a temperature of 600~1000℃ for 1~5 hours. Step 7: Add the powder obtained in step 6 to ethanol, then add PtPdRhRuCu mesoporous high-entropy alloy and sonicate to obtain a dispersion; wherein, the amount of balsamic charcoal added to ethanol is 40 mg, the amount of PtPdRhRuCu mesoporous high-entropy alloy is 10 mg, the volume of ethanol is 50 mL, and the sonication time is 1~2 h. Step 8: Filter the dispersion from Step 7, and then dry it in a vacuum drying oven to obtain the PtPdRhRuCu / C catalyst. The temperature of the vacuum drying oven is 50~90℃, and the drying time is 8~12 h.

[0019] Example This embodiment provides a method for preparing a composite catalyst based on the mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon, the specific steps of which include: Step 1: Dissolve 20 mg F127 completely in 1 mL of ultrapure water, add 0.4 mL of 40 mM K2PtCl4, Na2PdCl, Na3RhCl6, RuCl3·xH2O, CuCl2·2H2O and 1 mL of 40 mM RuCl3·xH2O, and stir for 1 h to obtain a brownish-red solution; Add 0.4 mL of 6.0 M hydrochloric acid solution to the obtained brownish-red solution and shake gently; Then add 2 mL of 0.1 M L-AA solution to the brown solution, and treat the entire solution system in an oil bath at 100°C for 24 hours to obtain a black solution; After centrifugation and washing of the black solution, it was freeze-dried to obtain a PtPdRhRuCu mesoporous high-entropy alloy. Step 2: Take an appropriate amount of balsa wood and carbonize it at high temperature in a tube furnace under an inert gas atmosphere. After the carbon is removed, grind it for one hour. Take 40 mg of carbon and add it to 50 mL of ethanol. Then add 10 mg of PtPdRhRuCu mesoporous high-entropy alloy and sonicate it for 1-2 h. After filtration, place it in a vacuum drying oven to dry and obtain the PtPdRhRuCu / C catalyst. The centrifuge speed was 14,000 rpm, the centrifugation time was 5 minutes, the number of centrifugations was more than 6, the centrifugation solvent was acetone / ethanol, and the high-temperature carbonization was carried out under an argon atmosphere at 5°C for 5 minutes. -1 The temperature was increased to 900℃ at a rapid rate and held for 3 hours.

[0020] Comparative Example 1 The preparation method of the non-mesoporous high-entropy alloy / carbon catalyst based on balsa wood-derived carbon differs from that in Example 1 in that F127 is not added in step 1. The other steps are as follows: Step 1: First, add 0.4 mL of 40 mM K2PtCl4, Na2PdCl, Na3RhCl6, RuCl3·xH2O, CuCl2·2H2O and 1 mL of 40 mM RuCl3·xH2O, and stir for 1 hour to obtain a brownish-yellow solution; Add 0.4 mL of 6.0 M hydrochloric acid solution to the obtained brownish-red solution and shake gently; Then add 2 mL of 0.1 M L-AA solution to the brown solution, and treat the entire solution system in an oil bath at 100°C for 24 hours to obtain a black solution; After centrifugation and washing of the black solution, it was freeze-dried to obtain a PtPdRhRuCu mesoporous high-entropy alloy. Step 2: Take an appropriate amount of balsa wood and carbonize it at high temperature in a tube furnace under an inert gas atmosphere. After the carbon is removed, grind it for one hour. Take 40 mg of carbon and add it to 50 mL of ethanol. Then add 10 mg of PtPdRhRuCu mesoporous high-entropy alloy and sonicate it for 1-2 h. After filtration, place it in a vacuum drying oven to dry and obtain the PtPdRhRuCu / C catalyst. The centrifuge speed was 14,000 rpm, the centrifugation time was 5 minutes, the number of centrifugations was more than 6, the centrifugation solvent was acetone / ethanol, and the high-temperature carbonization was carried out under an argon atmosphere at 5°C for 5 minutes. -1 The temperature was increased to 900℃ at a rapid rate and held for 3 hours.

[0021] Comparative Example 2 Preparation of Pt nanoparticles (NPs) Commercial Pt / C catalysts were used for catalytic property comparison.

[0022] A catalyst slurry with a concentration of 5 mg / mL was prepared for electrochemical detection. The preparation method was as follows: 10 mg of catalyst (MHEA / C, HEA / C) was placed in a 5 mL centrifuge tube, 2 mL of isopropanol and 40 μL of naphthol were added, and the mixture was sonicated for 30 min until it was evenly dispersed and dissolved to obtain the slurry for later use.

[0023] (1) SEM, TEM and corresponding element mapping analysis Observe the SEM image of Example 1, such as Figure 1 As shown, the synthesized MHEA exhibited mesoporous spherical pores (≈162 nm) and uniformly sized mesopores (≈10 nm), effectively ensuring a high specific surface area. The elemental mapping spectrum of MHEA / C in Example 1 was observed, as shown... Figure 1 As shown, the five elements exhibit the characteristic of having Pd as the core and the other four elements being evenly distributed, indicating the successful reduction of the five elements; while Comparative Example 1 shows a particle size of about 300 nm, with no mesopores generated, and the mapping image does not show a core-shell structure with Pd as the core. Figure 1 The crystallinity and clearly visible lattice fringes of Example 1 and Comparative Example 1 are clearly shown, with interplanar spacings of 0.22 and 0.19 nm, respectively. The concentric diffraction rings with bright discrete diffraction points are formally identified as face-centered cubic (FCC) structures, which can effectively promote electron transfer, increase the abundance of active sites, and improve the oxygen electrocatalytic performance of the materials.

[0024] (2) Phase analysis The surface crystal structure of the samples from Examples 1 and 2 was detected using X-ray diffraction. Figure 2 As shown, according to X-ray diffraction spectroscopy analysis and comparison with the PDF standard card, not only were peaks of amorphous carbon displayed, but also that MHEA and HEA are metal face-centered cubic structures with four diffraction peaks at 2θ = 40.7°, 47.2°, 69.3° and 83.2°, located on the (111), (200), (220) and (311) crystal planes, respectively. This is consistent with the results of transmission electron microscopy, and the crystallinity of Example 1 is better than that of Comparative Example 1.

[0025] (3) Analysis of scanning voltammetry and linear voltammetry curves for oxygen reduction reaction The oxygen reduction electrocatalytic performance of Example 1, Comparative Example 1, and Comparative Example 2 was tested using a standard three-electrode system and an electrochemical workstation. Figure 3 (a) This proves that the reaction occurring in the workstation is an oxygen reduction reaction; such as Figure 3 As shown in (b), the maximum diffusion current for oxygen reduction gradually increases with increasing rotational speed. Furthermore, comparing the LSV curves of Example 1, Comparative Example 1, and Comparative Example 2 reveals that MHEA / C exhibits better ORR kinetic activity compared to other catalysts. This indicates that MHEA / C demonstrates the best oxygen reduction catalytic performance.

[0026] (4) Analysis of Faraday efficiency of oxygen reduction reaction The Tafel slope of the oxygen reduction reaction was analyzed for Example 1, Comparative Example 1, and Comparative Example 2. Figure 3 (c) It can be seen that MHEA / C exhibits a lower Tafel slope, which further indicates that MHEA / C exhibits better ORR kinetic activity compared to other catalysts.

[0027] (5) Analysis of electron transfer number and H2O2 yield The number of transferred electrons and the yield of H2O2 in Example 1 were detected using a rotating ring-disk electrode and an electrochemical workstation. Figure 3 As shown in (d) and (e), MHEA / C maintains a low hydrogen peroxide conversion rate throughout the entire potential range, exhibiting high selectivity. Meanwhile, calculations show that the average number of electrons transferred during the reaction is 3.8, proving that the reaction occurs via a highly efficient four-electron reaction pathway throughout the entire potential range.

[0028] (6) Stability analysis of oxygen reduction reaction The oxygen reduction reaction stability of Example 1 was tested using a three-electrode system and an electrochemical workstation. Figure 3 (f) MHEA / C exhibits excellent oxygen reduction reaction stability, maintaining a high current density even after 36,000 s of continuous operation.

[0029] (7) Performance analysis of zinc-air batteries To verify whether the catalytic performance of MHEA / C in Example 1 can be used in practical applications, it was assembled with Comparative Examples 1 and 2 into a zinc-air battery for testing. At 6 mol L... -1 KOH solution and 0.2 mol L -1 Zinc acetate was prepared as an electrolyte, and MHEA / C loaded carbon paper was used as the air cathode. The zinc sheet was polished smooth to serve as the metal anode. Figure 4 (a) A photograph showing the assembled zinc-air battery illuminating an LED, based on the charge-discharge cycle curve. The LED was successfully lit when connected in series with the two assembled zinc-air batteries, demonstrating that the assembled battery can provide power to the LED. To further verify the performance of the assembled zinc-air battery, this paper tested its polarization curve and open-circuit voltage during operation and calculated its power density curve. Figure 4As shown in (b) and (c), the MHEA / C zinc-air battery exhibits a high open-circuit voltage (1.45 V) and a maximum power density of 152.5 mW / cm². -2 .like Figure 4 As shown in (d), the MHEA / C zinc-air battery has charge-discharge capability. The zinc-air battery loaded with MHEA / C was discharged at a current density of 5 mA cm⁻¹. -2 Below, its specific capacity was measured to be 834.4 mA hg. -1 (like Figure 4 (e) shows that the battery has a large specific capacity. This is demonstrated by the rate charge / discharge test (…). Figure 4 (f) It can be seen that as the current density increases exponentially, the voltage remains stable. When the current density decreases to 0, the discharge voltage can return to its initial state, indicating that the assembled zinc-air battery has good rate performance. To further confirm whether the assembled MHEA / C+RuO2 zinc-air battery has the ability to be used for a long time, its stability was tested. Figure 4 As shown in (g), the battery can operate stably for more than 350 hours after a short activation period, with the charging potential stabilizing at around 2.1 V and the discharging voltage stabilizing at around 1.22 V, demonstrating excellent charging and discharging efficiency and stability.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon, characterized in that, The specific steps include: Step 1: Dissolve F127 in 1 mL of ultrapure water, add 40 mM K2PtCl4, Na2PdCl4, Na3RhCl6, RuCl3·xH2O, and CuCl2·2H2O and stir for 1 hour to obtain a brownish-brown solution. Add 6.0 M hydrochloric acid solution to the obtained brownish-red solution and shake. Add 0.1 M L-AA solution to the brownish solution, and treat the entire solution system in an oil bath at 100°C for 24 hours to obtain a black solution. After centrifugation and washing of the black solution, it was freeze-dried to obtain a PtPdRhRuCu mesoporous high-entropy alloy. Step 2: Place the balsa wood in a tube furnace and carbonize it at high temperature in an inert gas atmosphere. After the process is complete, grind it for one hour and then add it to ethanol. Then, PtPdRhRuCu mesoporous high-entropy alloy was added and ultrasonically treated. After filtration, it was dried in a vacuum drying oven to obtain the PtPdRhRuCu / C catalyst.

2. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, The dosage of F127 in step 1 is 20 mg.

3. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 1, the amounts of K2PtCl4 and Na2PdCl4 are 0.3 mL, the amount of Na3RhCl6 is 0.5 mL, the amount of CuCl2·2H2O is 0.4 mL, and the amount of RuCl3·xH2O is 2 mL.

4. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 1, the amount of hydrochloric acid used is 0.5 mL, and the amount of L-AA used is 2 mL.

5. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 1, the black solution is washed by centrifuging at a speed of 14,000 rpm for 5 minutes, and the centrifugation is repeated at least 5 times.

6. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 2, the high-temperature carbonization is carried out under an argon atmosphere at 5°C for 5 minutes. -1 The temperature was increased to 900℃ at a rapid rate and held for 3 hours.

7. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 2, 40 mg of balsamic charcoal, 10 mg of PtPdRhRuCu mesoporous high-entropy alloy, and 50 mL of ethanol were added to the ethanol.

8. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 2, the ultrasonic treatment time for adding PtPdRhRuCu mesoporous high-entropy alloy is 1-2 hours.

9. The method for preparing a composite catalyst based on mesoporous high-entropy alloy PtPdRhRuCu / balsa wood-derived carbon according to claim 1, characterized in that, In step 2, the temperature of the vacuum drying oven is 60℃, and the drying time is 12 hours.

10. The application of a composite catalyst prepared by the method according to any one of claims 1 to 9, characterized in that, The composite catalyst is used in the cathode oxygen reduction reaction of a standard three-electrode system, wherein the reference electrode is an Ag / AgCl electrode, the working electrode is a disk electrode loaded with an electrocatalyst, and the counter electrode is a Pt sheet.

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