CN114695908A - Preparation and application of platinum-nickel nanoparticles supported by composite hollow graphene balls - Google Patents

Abstract

The invention discloses a composite hollow graphene ball loaded platinum-nickel nano particle and a preparation method and application thereof, wherein different atmosphere radio frequency plasmas are used for treating an iron-cobalt bimetallic nitrogen doped hollow graphene ball as a conductive network, and platinum-nickel nano particles are loaded on the hollow graphene ball; the prepared modified iron-cobalt bimetallic nitrogen-doped hollow graphene ball loaded platinum-nickel nano particles are applied to a methanol fuel cell multifunctional catalyst, can obviously enhance gas adsorption efficiency, improve oxygen reduction and methanol oxidation capacity, improve stability and conductivity in the reaction of catalyzing methanol fuel cells ORR and MOR, and have lower cost and good catalytic performance in the reaction of ORR and MOR.

Description

Preparation and application of platinum-nickel nanoparticles supported by composite hollow graphene balls

technical field

The invention belongs to the technical field of methanol fuel cell catalysts, and in particular relates to the preparation of composite hollow graphene ball-supported platinum-nickel nanoparticles and its application in methanol fuel cells.

Background technique

Energy is the material basis of human social activities and the driving force of world economic development. Non-renewable fossil energy such as coal, oil and natural gas is the most important energy consumed in the world. The energy crisis and environmental problems brought by traditional energy are the resistance to the sustainable development of human society. Rising energy demand, depletion of fossil fuel reserves, and environmental pollution have promoted research into energy conversion devices with high efficiency and low emissions. Fuel cells powered by renewable small molecules such as hydrogen, ethanol, formic acid and methanol, among others, may have the potential to meet these requirements. Fuel cell (FC) is a new power generation method that can directly convert chemical energy stored in fuel into electrical energy through electrochemical reaction without the need for a heat engine to do work and without going through the Carnot cycle. Because it also has the advantages of high power density and long service time, it is known as the fourth power technology after thermal power, hydropower and nuclear power. Direct methanol fuel cells (DMFCs) have attracted considerable interest in recent years due to their high power density, zero or low outgassing, easy charging, simple structure, and fast startup at low temperatures. However, there are still many obstacles in the road to commercialization of DMFC, such as: the electrochemical oxidation kinetics of DMFC at low temperature is slow, and methanol easily permeates from the anode to the cathode through the proton exchange membrane, which poisons the oxygen electrode; Catalysts are susceptible to poisoning by intermediates (CO) from methanol oxidation, and although considerable improvements have been achieved, DMFCs are still far from large-scale commercial applications. Currently, platinum and its alloys are commonly used as bifunctional catalysts for the oxygen reduction reaction and methanol oxidation reaction (MOR). limit. The catalysis of the oxygen reduction reaction on the platinum surface is mainly hindered by over-adsorbed oxygen-containing intermediates, especially at low-coordination surface sites. The combination of Pt and transition metals (Fe, Co, Ni) in the 3d structure can change the electronic structure of Pt, reduce the center of the d-band, weaken the adsorption of oxygen-containing species, and increase the surface active sites. Therefore, it is necessary to develop a catalyst with high utilization rate of Pt, methanol resistance, not easy to be poisoned, low cost and dual function of ORR/MOR catalysis.

Currently, carbon-based materials are widely used as nanoparticle carriers. Iron-cobalt bimetallic nitrogen-doped hollow graphene spheres have physicochemical properties such as unique hollow structure, excellent electronic conductivity, high mechanical strength, high specific surface area, and good chemical stability, and are considered to be an ideal electro- catalyst support material. However, due to the low surface activity (inert and hydrophobic) of the untreated composite hollow graphene spheres, it is difficult to disperse in most organic or inorganic solvents, so it is not easy to uniformly deposit small-sized platinum-nickel nanoparticles on its surface. In the field of electrocatalysis, great progress has been made in the modification of materials by radio frequency plasma, such as etching, doping or other surface treatments. The platinum-nickel nanoparticles are uniformly loaded on the surface of the composite hollow graphene sphere by the modification treatment of radio frequency plasma, and at the same time, heteroatom doping can be performed to change the electronic structure, vibration mode, chemical activity and mechanical properties of the carbon substrate. Improving the electrocatalytic performance and utilization of Pt is the key to efficient ORR/MOR bifunctional catalysts for methanol fuel cells.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of high specific surface area, high Pt utilization rate, good catalytic performance in different atmospheres radio frequency plasma treatment iron cobalt bimetal nitrogen doped hollow graphene ball support platinum nickel nanoparticle preparation method and its preparation method in methanol Applications in fuel cell electrode materials.

For realizing the above-mentioned technical purpose, the present invention adopts following technical scheme:

A preparation method of composite hollow graphene balls loaded with platinum-nickel nanoparticles, the composite hollow graphene balls are iron-cobalt bimetallic nitrogen-doped hollow graphene balls, and the iron-cobalt bimetallic nitrogen-doped hollow graphene balls ( FeCo/N _x HGS) is a carrier, the platinum-nickel nanoparticles are a carrier, and the carrier is loaded on the carrier by radio frequency plasma treatment.

A preparation method of composite hollow graphene ball-loaded platinum-nickel nanoparticles, the preparation steps include:

Step 1. Preparation of FeCo/N _x HGS: After self-assembly of graphene oxide (GO) and polystyrene balls (PS balls), polyaniline was coated on the surface, melamine was added as nitrogen source and carbon source, and then mixed with iron. The transition metal salt, the cobalt transition metal salt and the reducing agent are reacted, and then calcined to obtain FeCo/N _x HGS;

Step 2. Preparation of RF plasma-modified FeCo/N _x HGS: RF plasma-modified FeCo/N _x HGS is obtained by using the iron-cobalt bimetallic nitrogen-doped hollow graphene spheres prepared in step 1 by RF plasma surface treatment in different atmospheres ;

Step 3. Preparation of FeCo/N _{x HGS loaded with platinum-nickel nanoparticles: combining the RF plasma-modified FeCo/N x HGS} prepared in step 2 with platinum-nickel nanoparticles to obtain FeCo/N _x loaded with platinum-nickel nanoparticles HGS.

Further, the preparation step of FeCo/N _x HGS in described step 1 comprises:

(1) Add polystyrene balls (PS balls) into the hydrochloric acid solution and stir evenly, add graphene oxide to water for 20-40 minutes and then add it to the above-mentioned polystyrene ball solution, and conduct a magnetic stirring reaction at room temperature for 6-12 hours;

(2) adding melamine to the above-mentioned (1) solution, adding aniline after continuing the magnetic stirring reaction at room temperature for a period of time, and using an ice-water bath to keep the solution temperature at 0°C; then slowly adding oxidant ammonium persulfate to promote the synthesis of polyaniline , at the same time adding iron cobalt transition metal salts, and reacting in the dark for 10-24 hours, so that polyaniline can be uniformly polymerized on the surface of graphene;

(3) adding a reducing agent to the solution (2), refluxing at 90-120° C. to reduce graphene oxide to graphene, drying to obtain dark green graphene powder after the reaction, and mixing the graphene powder with melamine Dissolved in deionized water, mixed with magnetic stirring and reacted for a period of time, then filtered to collect the sample;

(4) The solid sample obtained in (3) was annealed in a high-temperature tube furnace with a reducing atmosphere, the reaction device was raised from room temperature to 380-450°C, stayed for 2 hours, then raised to 750°C, and continued high-temperature calcination for 1- For 3h, the sample prepared above was heated in a 2M sulfuric acid solution at 80°C for 4-10h to remove unstable and inactive substances in the sample, and then fully washed with deionized water to obtain FeCo/N _x HGS.

Further, the preparation of the radio frequency plasma modified FeCo/N _x HGS: the FeCo/N _x HGS will be put into a low temperature radio frequency plasma machine device, and different gases will be introduced to carry out discharge surface treatment modification.

Preferably, the different gas is one of argon, argon hydrogen, argon ammonia, nitrogen or oxygen.

Further, the preparation process of FeCo/N _x HGS loaded with platinum-nickel nanoparticles is as follows: hydrated nickel acetylacetonate, 1,2-tetradecanediol, oleic acid, and oleylamine are added to a three-necked flask containing dioctyl ether. , under nitrogen protection, the solution was heated to 60-90 °C and kept at a temperature to remove crystal water; then rapidly heated to 200 °C, then platinum acetylacetonate was dissolved in dichlorobenzene, and added to the reaction flask through a syringe; kept at 200 °C for 1-3 h , cooled to room temperature; added ethanol to obtain platinum-nickel nanoparticles, collected by centrifugation, washed with ethanol, and then dispersed in n-hexane; a certain amount of modified iron-cobalt bimetallic nitrogen-doped hollow graphene spheres were ultrasonically dispersed in n-hexane 15-30min; at the same time, the prepared platinum-nickel nanoparticles were also ultrasonically dispersed in n-hexane for 15-30min; after that, the nanoparticles were mixed with the substrate in the n-hexane solution, and ultrasonically dispersed for 0.5-1h; then collected by a centrifuge The catalyst was then completely dried overnight.

Preferably, in step 1, the polystyrene ball, hydrochloric acid, graphene oxide, melamine, aniline, ammonium persulfate, iron transition metal salt, cobalt transition metal salt, ammonia water, hydrazine hydrate, hollow graphene ball, melamine, The amount of sulfuric acid is 1500-2000mg, 80-100mL, 80-100mg, 2800-3000mg, 3-5mL, 12000-12500mg, 1000-1200mg, 1000-1200mg, 2-3mL, 0.1-0.2mL, 100-110mg, 1000 -1200mg, 30-50mL.

Preferably, the cobalt transition metal salt in step 1 adopts Co(NO ₃ ) ₂ ·6H ₂ O, CoCl ₂ ·6H ₂ O, Co(CH ₃ COO) ₂ , CoCl ₂ , CoSO ₄ ·7H ₂ O, CoSO ₄ One or more of H ₂ O, the iron transition metal salt adopts Fe(NO ₃ ) ₃ 9H ₂ O, FeCl ₃ 6H ₂ O, Fe(CH ₃ COO) ₃ , Fe ₂ (SO ₄ ) ₃ · 6H ₂ O in one or more.

Preferably, the reducing gas atmosphere in step 1 is Ar/H ₂ (7%H ₂ );

Preferably, in the second step, the pressure in the tube, the discharge power and the treatment time of the radio frequency plasma in different atmospheres are all 20Pa, 100W, 1h.

Preferably, in step 3, the hydrated nickel acetylacetonate, 1,2-tetradecanediol, oleic acid, oleylamine, dioctyl ether, platinum acetylacetonate, dichlorobenzene, ethanol, hexane, modified The amount of composite hollow graphene balls is 65-66mg, 69-70mg, 0.1-0.2mL, 0.1-0.2mL, 10-12mL, 40-45mg, 0.5-0.8mL, 20-25mL, 20-25mL, 66-70mg .

A kind of application of modified composite hollow graphene ball-loaded platinum-nickel nanoparticles as described above, which is used as a dual-function catalyst for methanol fuel cells, and is applied to catalyze ORR and MOR reactions of methanol cells, and hollow graphene spherical carbon doped with heteroatom The base material exhibits excellent electrocatalytic ORR performance, and doped heteroatoms, i.e. electron-rich or electron-poor, can polarize and change the spin density of adjacent carbon atoms, generate new catalytically active sites, and promote electrocatalyst surface intermediate The chemisorption/desorption of the body can improve the catalytic activity of ORR. The iron-cobalt bimetallic nitrogen-doped hollow graphene spheres are etched by radio frequency plasma, and the platinum-nickel nanoparticles are uniformly loaded on the surface of the composite hollow graphene spheres by doping. At the same time, heteroatom doping can be performed to change the electronic structure, vibration mode, chemical activity and mechanical properties of the carbon substrate, thereby improving the electrocatalytic performance.

Compared with the prior art, the present invention has the following beneficial effects:

(1) Iron cobalt nitrogen doped hollow graphene spheres (FeCo/N _x GHS) as a carrier, due to its three-dimensional (3D) and porous structure, are superior to ordinary carbon-based material carriers. The electron orbital energy of adjacent carbon atoms can further improve the excellent electrical conductivity of graphene, thereby improving the electron transfer ability; due to the three-dimensional hollow structure with stretchability, it is not easy to deform and collapse, and its stability is significantly improved; The outer surface of the hollow graphene spheres is coated with polyaniline, which can further form nitrogen-doped carbides during the calcination process, which can avoid the collapse of the spheres during the deposition of nanoparticles; Interaction of particles with Fe-Co bimetallic nitrogen-doped hollow graphene spheres contributes to enhanced electrochemical catalytic activity; Fe-Co alloy nanoparticles (NPs) exhibit better activity than their individual components; The alloyed NPs avoid the dissolution and erosion of the metal by the electrolyte, while preventing the aggregation of the NPs; the composite hollow graphene spheres have a porous structure, which enables them to better access the catalytic reaction, allowing rapid charge transfer in the catalytic reaction; the alloyed NPs are combined with The heterogeneous interface and strong coupling between the carbon shells help drive the fast reaction kinetics.

(2) Radio frequency plasma technology is based on a simple physical principle, obtaining energy supply, and the state of matter will change: from solid to liquid, and then from liquid to gas; and then providing more energy to the gas, the gas will be ionized , and enter a high-energy plasma state, which is the fourth state of matter; RF plasma etching, doping, reducing and increasing defects of Fe-Co-Ni doped hollow graphene spheres not only changes the electrons of the carbon substrate structure, vibration mode, chemical activity and mechanical properties, etc., and create conditions for the deposition of platinum-nickel nanoparticles.

(3) Pt-nickel nanoparticles enhance ORR activity and reduce Pt loading, improving Pt utilization. However, the catalyst structures using metal (alloy) nanoparticles on carbon supports suffer from severe defects, including agglomeration and exfoliation of alloy nanoparticles; moreover, carbon supports are susceptible to corrosion under typical direct methanol fuel cell operating conditions. Modified iron-cobalt-nitrogen-doped hollow graphene spheres can improve these problems, not only providing more electrochemically active sites, but also getting a rougher surface, which is beneficial for the deposition of platinum-nickel nanoparticles. Therefore, different atmospheres RF plasma treatment of iron-cobalt bimetallic nitrogen-doped hollow graphene balls supports platinum-nickel nanoparticles with higher specific surface area and more uniform distribution, platinum-nickel nanoparticles are uniformly grown on the surface of the carrier, which can effectively solve the traditional preparation The technical process has serious agglomeration problems, thereby improving its electrochemical performance.

(4) Pt-nickel nanoparticles supported by iron-cobalt bimetal nitrogen-doped hollow graphene spheres supported by RF plasma in different atmospheres can be directly used as electrode materials for methanol fuel cells, with the advantages of high Pt utilization and good stability.

Description of drawings

Figure 1. Microscopic morphology of the prepared argon RF plasma-treated iron-cobalt bimetal nitrogen-doped hollow graphene spheres loaded with platinum-nickel nanoparticles under a scanning electron microscope (SEM);

Fig. 2 Linear sweep voltammetry of the oxygen reduction reaction (ORR) of the prepared iron-cobalt bimetal nitrogen-doped hollow graphene spheres supported platinum-nickel nanoparticle catalysts in 0.1 M KOH solution saturated with _O2 prepared by RF plasma treatment in different atmospheres test chart (LSV);

Figure 3. Linear scans of the oxygen reduction reaction (ORR) of the prepared iron-cobalt bimetallic nitrogen-doped hollow graphene sphere-supported platinum _- nickel nanoparticle catalysts in _0.5MH2SO4 solution saturated with _O2 prepared by RF plasma treatment in different atmospheres Voltammetry chart (LSV).

Detailed ways

In order to make the objectives, technical solutions and beneficial technical effects of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments described in this specification are only for explaining the present invention, not for limiting the present invention. , the parameters, ratios, etc. of the embodiments can be selected according to local conditions and have no substantial impact on the results.

Embodiment 1: a kind of preparation method of composite hollow graphene ball loaded platinum nickel nanoparticle, specifically comprises the following steps:

(1) Synthesis of Fe-Co bimetallic nitrogen-doped hollow graphene spheres:

2 g of polystyrene spheres (PS ⁺ ) were added to 100 mL of 0.5M HCl solution and stirring was started. After 100 mg of GO was sonicated for 30 min, it was added to the above PS ⁺ solution, and the reaction was magnetically stirred at room temperature for 12 h. Then, 3 g of melamine was added, and the magnetic stirring reaction was continued for 12 h at room temperature. Then, 5 mL of aniline was added, and the temperature of the solution was kept at 0°C using an ice-water bath. Then slowly add the oxidant ammonium persulfate to promote the synthesis of polyaniline (the amount of ammonium persulfate added is calculated in the same number of moles as aniline), and also add transition metal salt 0.004mol FeCl ₃ ·6H ₂ O, 0.004mol Co ( NO ₃ ) ₂ ·6H ₂ O. The reaction was kept away from light for 24h, so that the polyaniline could be uniformly polymerized on the surface of graphene oxide. After that, a reducing agent (2 mL ammonia water, 0.1 mL N ₂ H ₄ ·H ₂ O) was added to the mixed solution, and then refluxed at 110° C. for 24 h to reduce graphene oxide to graphene (rGO). After the solution was dried in a blast drying oven to obtain dark green powder, 100 mg of the dark green powder sample prepared above and 1200 mg of melamine were mixed and dissolved in 25 mL of distilled water respectively, and the mixture was magnetically stirred and reacted for 12 h. The obtained mixed solution sample was collected by filtration under reduced pressure. The solid sample was then placed in the center of the high temperature tube furnace reactor. Ar/H ₂ (7%H ₂ ) mixed gas was introduced into one end, the reaction device was raised from room temperature to 420°C at a heating rate of 2°C/min, stayed for 2h, then increased to 750°C at 2°C/min, and continued high temperature calcination for 1h . The samples prepared above were heated in a 2M H ₂ SO ₄ solution at 80 °C for 8 h to remove unstable and inactive substances in the samples, and then fully washed with deionized water to obtain FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetallic nitrogen-doped hollow graphene spheres treated with argon RF plasma:

Put the iron cobalt nitrogen doped hollow graphene ball into a low-temperature radio frequency plasma reaction device, pass argon gas into it, control the pressure in the tube to be 20Pa, the discharge power of 100W, and the treatment time of 1h, and carry out radio frequency plasma discharge surface modification treatment. The obtained sample is denoted Ar-FeCo/N _x HGS.

(3) Synthesis of iron-cobalt bimetal nitrogen-doped hollow graphene spheres supported platinum-nickel nanoparticles treated by argon radio frequency plasma:

0.15mL of oleic acid and 0.15mL of oleylamine were added to a three-necked flask containing 10mL of dioctyl ether, then 69.1mg of 1,2-tetradecanediol and 65.78mg of hydrated nickel acetylacetonate were added, and nitrogen was passed for 30min to remove air. Under a stream of nitrogen, the solution was heated to 80 °C and held for 30 min to remove crystal water. The temperature rose to 200° C. within 20 min, and then 40 mg of platinum acetylacetonate was dissolved in 0.5 mL of dichlorobenzene, and then added to the reaction flask at one time through a syringe through insulating rubber. Incubate at 200°C for 1 h, then cool to room temperature. 20 mL of ethanol was added to precipitate the nanoparticles overnight, without removing the supernatant and without adding ethanol, directly collected by centrifugation (8000 rpm, 10 min), the nanoparticles were further washed with ethanol 3-4 times, and then dispersed in 20 mL of n-hexane. 66mg Ar-FeCo/N _x HGS was dispersed in 20 mL of n-hexane, ultrasonicated for 15 min, and the nanoparticles were ultrasonically dispersed in n-hexane for 15 min at the same time, and added dropwise to Ar-FeCo/N _x HGS in n-hexane through a dropper while stirring. , after the dropwise addition, ultrasonication was performed for 1 h, and then the catalyst was collected by centrifugation (3000 rpm, 5 min), and then completely dried overnight. To remove the surfactant, the catalyst was heated in air at 180°C for 1 hour. _N2 was then blown into the furnace at 180°C for 2 hours to remove _O2 , and then further annealed in a 400°C Ar/ _H2 (7% _H2 ) mixture for 4h. The resulting sample is denoted as Pt ₁ Ni ₂ @Ar-FeCo-N _x HGS.

The morphology of the Pt ₁ Ni ₂ @Ar-FeCo-N _x HGS material obtained in Example 1 was analyzed by scanning electron microscopy (SEM). The results are shown in Figure 1. The FeCo/N _x HGS structure is stable and the PtNi nanoparticles are stable. Evenly loaded on the carrier surface.

Bifunctional catalytic performance evaluation:

All electrochemical tests were performed using an electrochemical workstation model CHI 760E equipped with a PINE rotating disk electrode test system, and the electrochemical tests were performed at room temperature.

Preparation of working electrode: Before using rotating disk electrode (RDE), namely glassy carbon electrode (GCE, d = 0.4 cm), first use Al ₂ O ₃ powder to polish the electrode surface on a polishing cloth to a mirror surface, and then rinse with distilled water Several times, and ultrasonically oscillated for 10 s, and dried at room temperature for later use. Accurately weigh 4 mg of the Pt ₁ Ni ₂ @Ar-FeCo-N _x HGS material obtained in Example 1, 282 μL of isopropanol, 705 μL of deionized water, 13 μL of Nafion solution (5 wt. %) and mixed, the mixture was sonicated for 1 h, and finally 10 μL of the ink prepared above was evenly drop-coated on the surface of the GCE, and dried naturally to obtain the working electrode used for the test. The loading of the catalyst on the electrode surface is about 0.32 mg cm ^-2 . As a control experiment, a commercial 20 wt.% Pt/C catalyst was also prepared and tested using the same electrode preparation method.

Electrochemical performance test: A standard three-electrode electrochemical test system was used in the test process, wherein the counter electrode was a Pt sheet, the reference electrode was a saturated calomel electrode (SCE) and the working electrode prepared above.

The Pt ₁ Ni ₂ @Ar-FeCo-N _x HGS sample obtained in Example 1 was tested with a rotating disk electrode (RDE) for LSV in a solution of 0.1 M KOH and 0.5 MH ₂ SO ₄ saturated with O ₂ at 1600 rpm curve, the results are shown in Figures 2 and 3. The Pt ₁ Ni ₂ @Ar-FeCo-N _x HGS sample exhibits high ORR electrocatalytic activity with an onset potential and half-wave potential of 0.95 and 0.84 V in an alkaline environment, respectively vs. RHE, and an onset potential and a half-wave potential in an acidic environment of 0.95 and 0.84 V, respectively. The half-wave potentials are 0.83 and 0.75 V vs. RHE, respectively, and the Pt ₁ Ni ₂ @Ar-FeCo-N _x HGS samples exhibit high limiting current densities.

Comparative Example 1: Preparation of an iron-cobalt bimetallic nitrogen-doped hollow graphene ball supported platinum-nickel nanoparticles (Pt ₁ Ni ₂ @FeCo-N _x HGS), which specifically includes the following steps:

(1) Synthesis of FeCo bimetallic nitrogen-doped hollow graphene spheres (FeCo/N _x HGS):

2 g of polystyrene spheres (PS ⁺ ) were added to 100 mL of 0.5M HCl solution and stirring was started. After 100 mg of GO was sonicated for 30 min, it was added to the above PS ⁺ solution, and the reaction was magnetically stirred at room temperature for 12 h. Then, 3 g of melamine was added, and the magnetic stirring reaction was continued for 12 h at room temperature. Then, 5 mL of aniline was added, and the temperature of the solution was kept at 0°C using an ice-water bath. Then slowly add the oxidant ammonium persulfate to promote the synthesis of polyaniline (the amount of ammonium persulfate added is calculated in the same number of moles as aniline), and also add transition metal salt 0.004mol FeCl ₃ ·6H ₂ O, 0.004mol Co ( NO ₃ ) ₂ ·6H ₂ O. The reaction was kept away from light for 24h, so that the polyaniline could be uniformly polymerized on the graphene surface. After that, a reducing agent (2 mL ammonia water, 0.1 mL N ₂ H ₄ ·H ₂ O) was added to the mixed solution, and then refluxed at 110° C. for 24 h to reduce graphene oxide to graphene (rGO). After the solution was dried in a blast drying oven to obtain dark green powder, 100 mg of the dark green powder sample prepared above and 1200 mg of melamine were mixed and dissolved in 25 mL of distilled water respectively, and the mixture was magnetically stirred and reacted for 12 h. The obtained mixed solution sample was collected by filtration under reduced pressure. The solid sample was then placed in the center of the high temperature tube furnace reactor. Ar/H ₂ (7%H ₂ ) mixed gas was introduced into one end, the reaction device was raised from room temperature to 420°C at a heating rate of 2°C/min, stayed for 2h, then increased to 750°C at 2°C/min, and continued high temperature calcination for 1h . The samples prepared above were heated in a 2M H ₂ SO ₄ solution at 80 °C for 8 h to remove unstable and inactive substances in the samples, and then fully washed with deionized water to obtain FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetallic nitrogen-doped hollow graphene balls supported platinum-nickel nanoparticles:

0.15mL of oleic acid and 0.15mL of oleylamine were added to a three-necked flask containing 10mL of dioctyl ether, then 69.1mg of 1,2-tetradecanediol and 65.78mg of hydrated nickel acetylacetonate were added, and nitrogen was passed for 30min to remove air. Under a stream of nitrogen, the solution was heated to 80 °C and held for 30 min to remove crystal water. The temperature rose to 200° C. within 20 min, and then 40 mg of platinum acetylacetonate was dissolved in 0.5 mL of dichlorobenzene, and then added to the reaction flask at one time through a syringe through insulating rubber. Incubate at 200°C for 1 h, then cool to room temperature. Add 20 ml of ethanol overnight to precipitate the nanoparticles, without removing the supernatant and without adding ethanol, directly centrifuging to collect (8000 rpm, 10 min) the nanoparticles, further washed with ethanol 3-4 times, and then dispersed in 20 mL of n-hexane. 66mg FeCo/N _x HGS was dispersed in 20mL of n-hexane, ultrasonicated for 15min, meanwhile, the nanoparticles were ultrasonically dispersed in n-hexane for 15min, and added dropwise to the FeCo/N _x HGS n-hexane solution through a dropper while stirring, and added dropwise. After completion, sonicate for 1 h, then centrifuge (3000 rpm, 5 min) to collect the catalyst, and then completely dry overnight. To remove the surfactant, the catalyst was heated in air at 180 °C for 1 h. _N2 was then blown into the furnace at 180°C for 2 hours to remove _O2 , and then further annealed in a 400°C Ar/ _H2 (7% _H2 ) mixture for 4h. The resulting sample is denoted as Pt ₁ Ni ₂ @FeCo-N _x HGS.

The LSV curves of the Pt ₁ Ni ₂ @FeCo-N _x HGS sample catalyst in 0.1 MKOH and 0.5 MH ₂ SO ₄ solutions saturated with O ₂ at 1600 rpm were tested using a rotating disk electrode (RDE), and the results are shown in Figure 2 and 3 shown. The onset potential and half-wave potential of Pt ₁ Ni ₂ @FeCo-N _x HGS sample in alkaline environment are 0.93 and 0.83 V vs. RHE, respectively, and the onset potential and half-wave potential in acidic environment are 0.84 and 0.76 V vs. .RHE;

Embodiment 2: a kind of preparation method of composite hollow graphene ball-loaded platinum-nickel nanoparticles, specifically comprises the following steps:

(1) Synthesis of Fe-Co bimetallic nitrogen-doped hollow graphene spheres:

2 g of polystyrene spheres (PS ⁺ ) were added to 100 mL of 0.5M HCl solution and stirring was started. After 100 mg of GO was sonicated for 30 min, it was added to the above PS ⁺ solution, and the reaction was magnetically stirred at room temperature for 12 h. Then, 3 g of melamine was added, and the magnetic stirring reaction was continued for 12 h at room temperature. Then, 5 mL of aniline was added, and the temperature of the solution was kept at 0°C using an ice-water bath. Then slowly add the oxidant ammonium persulfate to promote the synthesis of polyaniline (the amount of ammonium persulfate added is calculated in the same number of moles as aniline), and also add transition metal salt 0.004mol FeCl ₃ ·6H ₂ O, 0.004mol Co ( NO ₃ ) ₂ ·6H ₂ O. The reaction was kept away from light for 24h, so that the polyaniline could be uniformly polymerized on the surface of graphene oxide. After that, a reducing agent (2 mL ammonia water, 0.1 mL N ₂ H ₄ ·H ₂ O) was added to the mixed solution, and then refluxed at 110° C. for 24 h to reduce graphene oxide to graphene (rGO). After the solution was dried in a blast drying oven to obtain dark green powder, 100 mg of the dark green powder sample prepared above and 1200 mg of melamine were mixed and dissolved in 25 mL of distilled water respectively, and the mixture was magnetically stirred and reacted for 12 h. The obtained mixed solution sample was collected by filtration under reduced pressure. The solid sample was then placed in the center of the high temperature tube furnace reactor. Ar/H ₂ (7%H ₂ ) mixed gas was introduced into one end, the reaction device was raised from room temperature to 420°C at a heating rate of 2°C/min, stayed for 2h, then increased to 750°C at 2°C/min, and continued high temperature calcination for 1h . The samples prepared above were heated in a 2M H ₂ SO ₄ solution at 80 °C for 8 h to remove unstable and inactive substances in the samples, and then fully washed with deionized water to obtain FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetallic nitrogen-doped hollow graphene spheres treated with argon-ammonia radio-frequency plasma:

Put the iron-cobalt bimetallic nitrogen-doped hollow graphene ball into the low-temperature radio frequency plasma reaction device, pass Ar/NH ₃ (7%NH ₃ ) into it, control the pressure in the tube to be 20Pa, the discharge power to be 100W, and the treatment time to be 1h. The surface modification treatment by radio frequency plasma discharge was carried out, and the obtained sample was recorded as Ar/NH ₃ -FeCo/N _x HGS.

(3) Synthesis of iron-cobalt bimetal nitrogen-doped hollow graphene sphere-supported platinum-nickel nanoparticles treated by argon-ammonia RF plasma:

0.15mL of oleic acid and 0.15mL of oleylamine were added to a three-necked flask containing 10mL of dioctyl ether, then 69.1mg of 1,2-tetradecanediol and 65.78mg of hydrated nickel acetylacetonate were added, and nitrogen was passed for 30min to remove air. Under a stream of nitrogen, the solution was heated to 80 °C and held for 30 min to remove crystal water. The temperature rose to 200° C. within 20 min, and then 40 mg of platinum acetylacetonate was dissolved in 0.5 mL of dichlorobenzene, and then added to the reaction flask at one time through a syringe through insulating rubber. Incubate at 200°C for 1 h, then cool to room temperature. 20 mL of ethanol was added to precipitate the nanoparticles overnight, without removing the supernatant and without adding ethanol, directly collected by centrifugation (8000 rpm, 10 min), the nanoparticles were further washed with ethanol 3-4 times, and then dispersed in 20 mL of n-hexane. 66mg Ar/NH ₃ -FeCo/N _x HGS was dispersed in 20 mL of n-hexane, ultrasonicated for 15 min, and the nanoparticles were ultrasonically dispersed in n-hexane for ₁₅ min. In N _x HGS n-hexane, after the dropwise addition, ultrasonication was performed for 1 h, and then the catalyst was collected by centrifugation (3000 rpm, 5 min), and then completely dried overnight. To remove the surfactant, the catalyst was heated in air at 180°C for 1 hour. _N2 was then blown into the furnace at 180°C for 2 hours to remove _O2 , and then further annealed in a 400°C Ar/ _H2 (7% _H2 ) mixture for 4h. The resulting sample was denoted as Pt ₁ Ni ₂ @Ar/NH ₃ -FeCo-N _x HGS.

The LSV curves of the Pt ₁ Ni ₂ @Ar/NH ₃ -FeCo-N _x HGS sample catalyst in 0.1MKOH and 0.5MH ₂ SO ₄ solution saturated with O ₂ at 1600 rpm were tested using a rotating disk electrode (RDE), The results are shown in Figures 2 and 3. The Pt ₁ Ni ₂ @Ar/NH ₃ -FeCo-N _x HGS sample exhibits high ORR electrocatalytic activity, with onset potential and half-wave potential of 0.96 and 0.85 V in alkaline environment vs. RHE, respectively, and onset in acidic environment. The onset potential and half-wave potential are 0.86 and 0.78V vs. RHE, respectively, and its electrocatalytic activity exceeds that of the Pt ₁ Ni ₂ @FeCo-N _x HGS catalyst obtained in Comparative Example 1 tested under the same conditions (onset potential under alkaline conditions). and half-wave potential of 0.93 and 0.83 V vs. RHE, respectively, and onset potential and half-wave potential of 0.84 and 0.76 V vs. RHE under acidic conditions), Pt ₁ Ni ₂ @Ar/NH ₃ -FeCo-N _x HGS The samples exhibited high limiting current densities. The above shows that the Pt ₁ Ni ₂ @Ar/NH ₃ -FeCo-N _x HGS material has fast reaction kinetics in the ORR electrocatalysis process.

Embodiment 3: a kind of preparation method of composite hollow graphene ball-loaded platinum-nickel nanoparticles, specifically comprises the following steps:

(1) Synthesis of Fe-Co bimetallic nitrogen-doped hollow graphene spheres:

2 g of polystyrene spheres (PS ⁺ ) were added to 100 mL of 0.5M HCl solution and stirring was started. After 100 mg of GO was sonicated for 30 min, it was added to the above PS ⁺ solution, and the reaction was magnetically stirred at room temperature for 12 h. Then, 3 g of melamine was added, and the magnetic stirring reaction was continued for 12 h at room temperature. Then, 5 mL of aniline was added, and the temperature of the solution was kept at 0°C using an ice-water bath. Then slowly add the oxidant ammonium persulfate to promote the synthesis of polyaniline (the amount of ammonium persulfate added is calculated in the same number of moles as aniline), and also add transition metal salt 0.004mol FeCl ₃ ·6H ₂ O, 0.004mol Co ( NO ₃ ) ₂ ·6H ₂ O. The reaction was kept away from light for 24h, so that the polyaniline could be uniformly polymerized on the surface of graphene oxide. After that, a reducing agent (2 mL ammonia water, 0.1 mL N ₂ H ₄ ·H ₂ O) was added to the mixed solution, and then refluxed at 110° C. for 24 h to reduce graphene oxide to graphene (rGO). After the solution was dried in a blast drying oven to obtain dark green powder, 100 mg of the dark green powder sample prepared above and 1200 mg of melamine were mixed and dissolved in 25 mL of distilled water respectively, and the mixture was magnetically stirred and reacted for 12 h. The obtained mixed solution sample was collected by filtration under reduced pressure. The solid sample was then placed in the center of the high temperature tube furnace reactor. Ar/H ₂ (7%H ₂ ) mixed gas was introduced into one end, the reaction device was raised from room temperature to 420°C at a heating rate of 2°C/min, stayed for 2h, then increased to 750°C at 2°C/min, and continued high temperature calcination for 1h . The samples prepared above were heated in a 2M H ₂ SO ₄ solution at 80 °C for 8 h to remove unstable and inactive substances in the samples, and then fully washed with deionized water to obtain FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetallic nitrogen-doped hollow graphene spheres treated with oxygen radio frequency plasma:

The iron-cobalt bimetal nitrogen-doped hollow graphene balls were put into a low-temperature radio frequency plasma reaction device, oxygen was introduced into it, the pressure in the control tube was 20Pa, the discharge power was 100W, and the treatment time was 1h, and the surface modification treatment by radio frequency plasma discharge was carried out. , and the obtained sample is denoted as O ₂ -FeCo/N _x HGS.

(3) Synthesis of iron-cobalt bimetal nitrogen-doped hollow graphene balls supported by oxygen radio frequency plasma treated platinum-nickel nanoparticles:

0.15mL of oleic acid and 0.15mL of oleylamine were added to a three-necked flask containing 10mL of dioctyl ether, then 69.1mg of 1,2-tetradecanediol and 65.78mg of hydrated nickel acetylacetonate were added, and nitrogen was passed for 30min to remove air. Under a stream of nitrogen, the solution was heated to 80 °C and held for 30 min to remove crystal water. The temperature rose to 200° C. within 20 min, and then 40 mg of platinum acetylacetonate was dissolved in 0.5 mL of dichlorobenzene, and then added to the reaction flask at one time through a syringe through insulating rubber. Incubate at 200°C for 1 h, then cool to room temperature. 20 mL of ethanol was added to precipitate the nanoparticles overnight, without removing the supernatant and without adding ethanol, directly collected by centrifugation (8000 rpm, 10 min), the nanoparticles were further washed with ethanol 3-4 times, and then dispersed in 20 mL of n-hexane. 66mgO ₂ -FeCo/N _x HGS was dispersed in 20mL of n-hexane, ultrasonicated for 15min, at the same time the nanoparticles were ultrasonically dispersed in n-hexane for 15min, under stirring, added dropwise to O ₂ -FeCo/N _x HGS n-hexane through a dropper In alkane, after the dropwise addition, ultrasonication was performed for 1 h, and then the catalyst was collected by centrifugation (3000 rpm, 5 min), and then completely dried overnight. To remove the surfactant, the catalyst was heated in air at 180°C for 1 hour. _N2 was then blown into the furnace at 180°C for 2 hours to remove _O2 , and then further annealed in a 400°C Ar/ _H2 (7% _H2 ) mixture for 4h. The resulting sample is denoted as Pt ₁ Ni ₂ @O ₂ -FeCo-N _x HGS.

The LSV curve of Pt ₁ Ni ₂ @O ₂ -FeCo-N _x HGS sample catalyst in saturated O ₂ solution of 0.1MKOH and 0.5MH ₂ SO ₄ at 1600 rpm was tested by rotating disk electrode (RDE), and the results are as follows Figure 2 and Figure 3. The onset potential and half-wave potential of Pt ₁ Ni ₂ @O ₂ -FeCo-N _x HGS in alkaline environment are 0.93 and 0.82 V, respectively vs. RHE, and the onset potential and half-wave potential in acidic environment are 0.81 and 0.73, respectively V vs. RHE.

Embodiment 4: a kind of preparation of composite hollow graphene ball-loaded platinum-nickel nanoparticles, specifically comprises the following steps:

(1) Synthesis of Fe-Co bimetallic nitrogen-doped hollow graphene spheres:

2 g of polystyrene spheres (PS ⁺ ) were added to 100 mL of 0.5M HCl solution and stirring was started. After 100 mg of GO was sonicated for 30 min, it was added to the above PS ⁺ solution, and the reaction was magnetically stirred at room temperature for 12 h. Then, 3 g of melamine was added, and the magnetic stirring reaction was continued for 12 h at room temperature. Then, 5 mL of aniline was added, and the temperature of the solution was kept at 0°C using an ice-water bath. Then slowly add the oxidant ammonium persulfate to promote the synthesis of polyaniline (the amount of ammonium persulfate added is calculated in the same number of moles as aniline), and also add transition metal salt 0.004mol FeCl ₃ ·6H ₂ O, 0.004mol Co ( NO ₃ ) ₂ ·6H ₂ O. The reaction was kept away from light for 24h, so that the polyaniline could be uniformly polymerized on the surface of graphene oxide. After that, a reducing agent (2 mL ammonia water, 0.1 mL N ₂ H ₄ ·H ₂ O) was added to the mixed solution, and then refluxed at 110° C. for 24 h to reduce graphene oxide to graphene (rGO). After the solution was dried in a blast drying oven to obtain dark green powder, 100 mg of the dark green powder sample prepared above and 1200 mg of melamine were mixed and dissolved in 25 mL of distilled water respectively, and the mixture was magnetically stirred and reacted for 12 h. The obtained mixed solution sample was collected by filtration under reduced pressure. The solid sample was then placed in the center of the high temperature tube furnace reactor. Ar/H ₂ (7%H ₂ ) mixed gas was introduced into one end, the reaction device was raised from room temperature to 420°C at a heating rate of 2°C/min, stayed for 2h, then increased to 750°C at 2°C/min, and continued high temperature calcination for 1h . The samples prepared above were heated in a 2M H ₂ SO ₄ solution at 80 °C for 8 h to remove unstable and inactive substances in the samples, and then fully washed with deionized water to obtain FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetal nitrogen-doped hollow graphene spheres treated by nitrogen radio frequency plasma:

Put the iron-cobalt bimetal nitrogen-doped hollow graphene ball into the low-temperature radio frequency plasma reaction device, pass nitrogen gas into it, control the pressure in the tube to be 20Pa, the discharge power of 100W, and the treatment time of 1h, and carry out the surface modification treatment of radio frequency plasma discharge. , and the obtained sample is denoted as N ₂ -FeCo/N _x HGS.

(3) Synthesis of iron-cobalt bimetal nitrogen-doped hollow graphene ball-supported platinum-nickel nanoparticles treated by nitrogen radio frequency plasma:

0.15mL of oleic acid and 0.15mL of oleylamine were added to a three-necked flask containing 10mL of dioctyl ether, then 69.1mg of 1,2-tetradecanediol and 65.78mg of hydrated nickel acetylacetonate were added, and nitrogen was passed for 30min to remove air. Under a stream of nitrogen, the solution was heated to 80 °C and held for 30 min to remove crystal water. The temperature rose to 200° C. within 20 min, and then 40 mg of platinum acetylacetonate was dissolved in 0.5 mL of dichlorobenzene, and then added to the reaction flask at one time through a syringe through insulating rubber. Incubate at 200°C for 1 h, then cool to room temperature. 20 mL of ethanol was added to precipitate the nanoparticles overnight, without removing the supernatant and without adding ethanol, directly collected by centrifugation (8000 rpm, 10 min), the nanoparticles were further washed with ethanol 3-4 times, and then dispersed in 20 mL of n-hexane. _66mg N _{2 -FeCo} /N _x HGS was dispersed in 20mL of n-hexane, ultrasonicated for 15min, at the same time, the nanoparticles were ultrasonically dispersed in n-hexane for 15min. In alkane, after the dropwise addition, ultrasonication was performed for 1 h, and then the catalyst was collected by centrifugation (3000 rpm, 5 min), and then completely dried overnight. To remove the surfactant, the catalyst platinum nickel nanoparticles were heated in air at 180 °C for 1 hour. _N2 was then blown into the furnace at 180°C for 2 hours to remove _O2 , and then further annealed in a 400°C Ar/ _H2 (7% _H2 ) mixture for 4h. The resulting sample is denoted as Pt ₁ Ni ₂ @N ₂ -FeCo-N _x HGS.

The LSV curve of Pt ₁ Ni ₂ @N ₂ -FeCo-N _x HGS sample catalyst in saturated O ₂ solution of 0.1MKOH and 0.5MH ₂ SO ₄ at 1600 rpm was tested by rotating disk electrode (RDE), and the results are as follows Figure 2 and Figure 3. The onset potential and half-wave potential of Pt ₁ Ni ₂ @N ₂ -FeCo-N _x HGS in alkaline environment are 0.94 and 0.84 V, respectively vs. RHE, and the onset potential and half-wave potential in acidic environment are 0.82 and 0.75, respectively V vs. RHE.

Embodiment 5: a kind of preparation of composite hollow graphene ball-loaded platinum-nickel nanoparticles, specifically comprises the following steps:

(1) Synthesis of Fe-Co bimetallic nitrogen-doped hollow graphene spheres:

2 g of polystyrene spheres (PS ⁺ ) were added to 100 mL of 0.5M HCl solution and stirring was started. After 100 mg of GO was sonicated for 30 min, it was added to the above PS ⁺ solution, and the reaction was magnetically stirred at room temperature for 12 h. Then, 3 g of melamine was added, and the magnetic stirring reaction was continued for 12 h at room temperature. Then, 5 mL of aniline was added, and the temperature of the solution was kept at 0°C using an ice-water bath. Then slowly add the oxidant ammonium persulfate to promote the synthesis of polyaniline (the amount of ammonium persulfate added is calculated in the same number of moles as aniline), and also add transition metal salt 0.004mol FeCl ₃ ·6H ₂ O, 0.004mol Co ( NO ₃ ) ₂ ·6H ₂ O. The reaction was kept away from light for 24h, so that the polyaniline could be uniformly polymerized on the surface of graphene oxide. After that, a reducing agent (2 mL ammonia water, 0.1 mL N ₂ H ₄ ·H ₂ O) was added to the mixed solution, and then refluxed at 110° C. for 24 h to reduce graphene oxide to graphene (rGO). After the solution was dried in a blast drying oven to obtain dark green powder, 100 mg of the dark green powder sample prepared above and 1200 mg of melamine were mixed and dissolved in 25 mL of distilled water respectively, and the mixture was magnetically stirred and reacted for 12 h. The obtained mixed solution sample was collected by filtration under reduced pressure. The solid sample was then placed in the center of the high temperature tube furnace reactor. Ar/H ₂ (7%H ₂ ) mixed gas was introduced into one end, the reaction device was raised from room temperature to 420°C at a heating rate of 2°C/min, stayed for 2h, and then increased to 750°C at 2°C/min, and continued calcination at high temperature for 1h . The samples prepared above were heated in a 2M H ₂ SO ₄ solution at 80 °C for 8 h to remove unstable and inactive substances in the samples, and then fully washed with deionized water to obtain FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetal nitrogen-doped hollow graphene spheres treated with argon hydrogen radio frequency plasma:

Put the iron-cobalt bimetallic nitrogen-doped hollow graphene ball into the low-temperature radio frequency plasma reaction device, pass Ar/H ₂ (7%H ₂ ) into it, control the pressure in the tube to be 20Pa, the discharge power of 100W, and the treatment time of 1h, The surface modification treatment by radio frequency plasma discharge was carried out, and the obtained sample was recorded as Ar/H ₂ -FeCo/N _x HGS.

(2) Synthesis of iron-cobalt bimetallic nitrogen-doped hollow graphene sphere-supported platinum-nickel nanoparticles treated by argon hydrogen radio frequency plasma:

0.15mL of oleic acid and 0.15mL of oleylamine were added to a three-necked flask containing 10mL of dioctyl ether, then 69.1mg of 1,2-tetradecanediol and 65.78mg of hydrated nickel acetylacetonate were added, and nitrogen was passed for 30min to remove air. Under a stream of nitrogen, the solution was heated to 80 °C and held for 30 min to remove crystal water. The temperature rose to 200° C. within 20 min, and then 40 mg of platinum acetylacetonate was dissolved in 0.5 mL of dichlorobenzene, and then added to the reaction flask at one time through a syringe through insulating rubber. Incubate at 200°C for 1 h, then cool to room temperature. 20 mL of ethanol was added to precipitate the nanoparticles overnight, without removing the supernatant and without adding ethanol, directly collected by centrifugation (8000 rpm, 10 min), the nanoparticles were further washed with ethanol 3-4 times, and then dispersed in 20 mL of n-hexane. 66mg Ar/H _{2 -FeCo} /N _x HGS was dispersed in 20mL of n-hexane, ultrasonicated for 15min, and the nanoparticles were ultrasonically dispersed in n-hexane for 15min. In N _x HGS n-hexane, after the dropwise addition, ultrasonication was performed for 1 h, and then the catalyst was collected by centrifugation (3000 rpm, 5 min), and then completely dried overnight. To remove the surfactant, the catalyst was heated in air at 180°C for 1 hour. _N2 was then blown into the furnace at 180°C for 2 hours to remove _O2 , and then further annealed in a 400°C Ar/ _H2 (7% _H2 ) mixture for 4h. The resulting sample is denoted as Pt ₁ Ni ₂ @Ar/H ₂ -FeCo-N _x HGS.

The LSV curves of the Pt ₁ Ni ₂ @Ar/H ₂ -FeCo-N _x HGS sample catalyst in 0.1MKOH and 0.5MH ₂ SO ₄ solution saturated with O ₂ at 1600 rpm were tested using a rotating disk electrode (RDE), The results are shown in Figures 2 and 3. The Pt ₁ Ni ₂ @Ar/H ₂ -FeCo-N _x HGS sample exhibits high ORR electrocatalytic activity, with onset potential and half-wave potential of 0.94 and 0.84 V in alkaline environment vs. RHE, respectively, and onset in acidic environment. The onset potential and half-wave potential were 0.83 and 0.74 V vs. RHE, respectively.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: It is still possible to modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements to some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. range.

Claims (10)

1. The preparation method of the composite hollow graphene ball loaded with the platinum-nickel nanoparticles is characterized in that the composite hollow graphene ball is an iron-cobalt bimetallic nitrogen-doped hollow graphene ball (FeCo/N) which is doped with iron-cobalt bimetallic nitrogen_xHGS) is a carrier, the platinum nickel nano particles are a load, and the load is loaded on the carrier through radio frequency plasma treatment.

2. The preparation method of the composite hollow graphene sphere-loaded platinum-nickel nanoparticle according to claim 1, wherein the preparation method specifically comprises the following steps:

step one, FeCo/N_xPreparation of HGS: after Graphene Oxide (GO) and polystyrene spheres (PS spheres) are self-assembled, polyaniline is coated on the surface, melamine is added as a nitrogen source and a carbon source, then the polyaniline reacts with iron transition metal salt, cobalt transition metal salt and a reducing agent, and FeCo/N is obtained by calcining_xHGS；

Step two, radio frequency plasmaDaughter-modified FeCo/N_xPreparation of HGS: the method comprises the step of processing the surfaces of the radio frequency plasmas in different atmospheres by adopting the iron-cobalt bimetallic nitrogen doped hollow graphene ball prepared in the step I to obtain the radio frequency plasma modified FeCo/N_xHGS；

Step three, FeCo/N loaded with platinum-nickel nano particles_xPreparation of HGS: modifying FeCo/N by the radio frequency plasma prepared in the step two_xFeCo/N loaded with platinum-nickel nanoparticles obtained by combining HGS and platinum-nickel nanoparticles_xHGS。

3. The method for preparing platinum-nickel nanoparticles loaded on composite hollow graphene spheres according to claim 2, wherein FeCo/N is adopted in the first step_xThe preparation steps of the HGS comprise:

(1) adding polystyrene spheres (PS spheres) into a hydrochloric acid solution, uniformly stirring, adding graphene oxide into water, performing ultrasonic treatment for 20-40 min, adding the graphene oxide into the polystyrene sphere solution, and performing magnetic stirring reaction at room temperature for 6-12 h;

(2) adding melamine into the solution (1), continuously carrying out magnetic stirring reaction at room temperature for a period of time, adding aniline, and keeping the temperature of the solution at 0 ℃ by adopting an ice-water bath; slowly adding an oxidant ammonium persulfate to promote the synthesis of polyaniline, simultaneously adding iron-cobalt transition metal salt, and reacting for 10-24 hours in a dark place to ensure that the polyaniline can be uniformly polymerized on the surface of the graphene;

(3) adding a reducing agent into the solution (2), refluxing at 90-120 ℃ to reduce graphene oxide into graphene, drying after reaction to obtain dark green graphene powder, mixing the graphene powder and melamine, dissolving in deionized water, mixing, magnetically stirring, reacting for a period of time, filtering and collecting a sample;

(4) annealing the solid sample obtained in the step (3) in a reducing atmosphere high-temperature tube furnace, heating the reaction device from room temperature to 380-450 ℃, preserving heat for 2h, then heating to 750 ℃, continuing to calcine at high temperature for 1-3 h, cooling to room temperature, heating the prepared sample in 2M sulfuric acid solution at 80 ℃ for 4-10 h to remove unstable and inactive substances in the sample, and fully washing with deionized water to obtain FeCo/N_xHGS。

4. The method for preparing composite hollow graphene sphere loaded platinum-nickel nanoparticles according to claim 2, wherein the radio frequency plasma modified FeCo/N_xPreparation of HGS: FeCo/N_xPutting the HGS into a low-temperature radio frequency plasma machine device, and introducing different gases to carry out discharge surface treatment modification.

5. The method for preparing the composite hollow graphene sphere-loaded platinum-nickel nanoparticle according to claim 4, wherein the different gas is one of argon, argon-hydrogen, argon-ammonia, nitrogen or oxygen.

6. The method for preparing the composite hollow graphene sphere loaded platinum-nickel nanoparticle as claimed in claim 2, wherein the platinum-nickel nanoparticle loaded FeCo/N is_xThe preparation process of the HGS comprises the following steps: adding hydrated nickel acetylacetonate, 1, 2-tetradecanediol, oleic acid and oleylamine into a three-neck flask containing dioctyl ether, heating the solution to 60-90 ℃ under the protection of nitrogen, and keeping the temperature to remove crystal water; rapidly heating to 200 ℃, dissolving acetylacetone platinum in dichlorobenzene, adding into a reaction bottle through an injector, preserving heat for 1-3 h at 200 ℃, and cooling to room temperature; adding ethanol to obtain platinum nickel nanoparticles, centrifuging, collecting, washing with ethanol, and dispersing in n-hexane; ultrasonically dispersing a certain amount of modified iron-cobalt bimetallic nitrogen doped hollow graphene balls in n-hexane for 15-30 min, and ultrasonically dispersing the prepared platinum-nickel nanoparticles in the n-hexane for 15-30 min; and mixing the nano particles with the substrate in a normal hexane solution, carrying out ultrasonic dispersion for 0.5-1 h, collecting the catalyst by using a centrifugal machine, and drying.

7. The method for preparing the composite hollow graphene ball-loaded platinum nickel nanoparticle as claimed in claim 3, wherein in the first step, the amounts of the polystyrene ball, the hydrochloric acid, the oxidized graphene, the melamine, the aniline, the ammonium persulfate, the iron transition metal salt, the cobalt transition metal salt, the ammonia water, the hydrazine hydrate, the hollow graphene ball, the melamine and the sulfuric acid are 1500-2000mg, 80-100mL, 80-100mg, 2800-3000mg, 3-5mL, 12000-12500mg, 1000-1200mg, 2-3mL, 0.1-0.2mL, 100-110mg, 1000-1200mg and 30-50mL respectively.

8. The method for preparing composite hollow graphene sphere loaded platinum-nickel nanoparticles according to claim 7, wherein the cobalt transition metal salt in the first step is Co (NO)₃)₂·6H₂O、CoCl₂·6H₂O、Co(CH₃COO)₂、CoCl₂、CoSO₄·7H₂O、CoSO₄·H₂One or more of O, Fe (NO) is adopted as the iron transition metal salt₃)₃·9H₂O、FeCl₃·6H₂O、Fe(CH₃COO)₃、Fe₂(SO₄)₃·6H₂And one or more of O.

9. The method for preparing the platinum-nickel nanoparticle loaded on the composite hollow graphene sphere according to claim 6, wherein the amounts of the hydrated nickel acetylacetonate, 1, 2-tetradecanediol, oleic acid, oleylamine, dioctyl ether, platinum acetylacetonate, dichlorobenzene, ethanol, n-hexane and the modified composite hollow graphene sphere are 65-66mg, 69-70mg, 0.1-0.2mL, 10-12mL, 40-45mg, 0.5-0.8mL, 20-25mL and 66-70mg, respectively.

10. The application of the modified composite hollow graphene ball-loaded platinum-nickel nanoparticles is characterized in that the modified composite hollow graphene ball-loaded platinum-nickel nanoparticles are used as a bifunctional catalyst of a methanol fuel cell and applied to catalyzing ORR and MOR reactions of the methanol fuel cell, have excellent electrocatalysis ORR performance, can promote chemical adsorption/desorption of an intermediate on the surface of the electrocatalysis, and improve catalytic activity of ORR.

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