Platinum-carbon catalyst taking hollow carbon nanospheres as carrier and preparation method of platinum-carbon catalyst

Abstract

The invention provides a platinum-carbon catalyst taking hollow carbon nanospheres as a carrier and a preparation method of the platinum-carbon catalyst. The method comprises the following steps: adding a polymer monomer into a nano template dispersion liquid with a uniform size; then adding a proper amount of platinum salt into the solution to obtain a mixed solution, and stirring to react for 0.5-30 hours to obtain a reaction product; and annealing the reaction product, and then removing the nano template to obtain the platinum-carbon catalyst. The obtained platinum-carbon catalyst takes the hollow carbon nanospheres as a carrier and has a larger specific surface area, the platinum catalyst is loaded on the surfaces of the carbon nanospheres and can be in better contact with an electrolyte, and the obtained catalyst has good electrochemical activity and shows excellent electro-catalytic hydrogen evolution performance and oxygen reduction performance; and the related preparation method is simple and reliable, is suitable for preparation of an electrocatalytic hydrogen evolution electrode and an oxygen reduction electrode, and has a good application prospect in the fields of proton exchange membrane electrolytic cells, hydrogen fuel cells and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano hydrogen evolution catalysts, and particularly relates to a platinum-carbon catalyst supported by hollow nano-carbon spheres and a preparation method thereof. Background Art

[0002] Since the 21st century, the rapid growth of the population and the high-speed development of society have led to a sharp increase in the demand for energy by humans. 80% of the energy we need comes from fossil fuels. However, the long-term use of fossil fuels will ultimately lead to the depletion of fossil fuels and cause damage to the environment (Walter M G, Warren E L, McKone J R, et al. Solar watersplitting cells[J]. Chemical Reviews, 2010, 110(11): 6446-6473). Therefore, to solve this problem, we must shift from using fossil fuels to using clean energy with rich resources and low pollution. However, the intermittency and unpredictability of most secondary energy sources result in low energy utilization efficiency. Among them, hydrogen has excellent storage and transportation properties, and hydrogen energy has rich reserves, renewable properties, and near-zero emissions, so it is regarded as the ultimate energy source that can replace fossil fuels (Li X, Zhao L, Yu J, et al. Water splitting: from electrode to greenenergy system[J]. Nano-Micro Letters, 2020, 12: 1-29). In the method of hydrogen production, compared with other methods such as hydrogen production from fossil fuels, water electrolysis for hydrogen evolution is an efficient, green, and sustainable hydrogen production method, and the hydrogen produced is called "green hydrogen". However, the hydrogen evolution reaction (HER) of most electrocatalytic materials usually shows a high overpotential. Therefore, the development of high-activity and low-cost electrode materials and the improvement of electrolysis efficiency are the current research hotspots.

[0003] Among them, platinum metal still has irreplaceable advantages as the "benchmark" of catalysts. Platinum has an almost zero theoretical overpotential and good catalytic stability under a wide range of pH conditions. Therefore, further in-depth research on platinum-based catalysts is of great significance. However, its natural content is low and the cost is high, which limits its large-scale application. At present, using a suitable carrier is a common method to solve the cost and improve the utilization rate. Among them, carbon materials usually have a high specific surface area and high conductivity, which can provide rich active sites for it, reduce the amount of platinum used, and at the same time, platinum-carbon catalysts show good hydrogen evolution performance and oxygen reduction performance. At present, there are many preparation methods for platinum-carbon catalysts. For example, "A Platinum-Carbon Catalyst and Its Preparation Method" (CN202310680852.9) loads platinum nanoparticles onto carbon black by reducing them with ethylene glycol; "Platinum-Carbon Catalyst, Its Preparation Method and Application, and Hydrogen Fuel Cell" (CN202111275071.9) uses a reducing agent containing polyvinylpyrrolidone and formic acid to reduce a platinum-containing solution to prepare the catalyst; "Platinum-Carbon Catalyst, Its Preparation Method and Application" (CN202210168801.3) reduces platinum onto nitrogen-modified conductive carbon black under a reducing atmosphere. The above-mentioned preparation methods have successfully prepared platinum-carbon catalysts, but during the reduction process, platinum particles are prone to agglomeration, reducing the mass activity, and some platinum nanoparticles will enter the interior of the carbon material, affecting its catalytic activity.

[0004] Currently, commercial carbon black is still the most widely used carrier. For platinum-carbon catalysts using this as the carrier, some platinum nanoparticles penetrate deep into the interior of the carbon material and do not come into full contact with the electrolyte. Moreover, the density of platinum-carbon catalysts is relatively large, resulting in problems such as a lower specific surface area of the catalyst, low mass activity, and poor dispersibility. Therefore, in recent years, different types of carbon carriers have been invented, and the functionalization and modification of carbon carriers have been widely studied. For example, in "A Preparation Method and Application of MOF-Derived Mesoporous Carbon" (CN202310373658.6), a novel MOF-derived mesoporous carbon is used as the carbon carrier of the platinum-based catalyst.

[0005] Therefore, it is of great significance to invent a new type of carbon carrier and a preparation method for platinum-carbon catalysts that have good electrocatalytic hydrogen evolution performance and oxygen reduction performance and can effectively solve problems such as catalyst agglomeration, mass activity, and dispersibility. Summary of the Invention

[0006] The main object of the present invention is to provide a platinum-carbon catalyst supported on hollow carbon nanospheres in view of the problems and deficiencies existing in the prior art. The prepared hollow carbon nanospheres have uniform sizes, high specific surface areas and abundant active sites. The platinum nanoparticles are uniformly distributed on the outer surface of the hollow carbon nanospheres, enabling sufficient contact with the electrolyte. Moreover, the hollow structure significantly reduces the density of the platinum-carbon catalyst, and its suspension has good dispersibility and is not prone to sedimentation, making it more suitable for the requirements of the membrane electrode preparation process. The present invention exhibits good electrocatalytic hydrogen evolution performance and oxygen reduction performance. In addition, the involved preparation method is simple and reliable, applicable to the preparation of electrocatalytic hydrogen evolution electrodes and oxygen reduction electrodes, and has good application prospects in fields such as proton exchange membrane electrolyzers and hydrogen fuel cells.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows:

[0008] A preparation method of a platinum-carbon catalyst supported on hollow carbon nanospheres, comprising the following steps:

[0009] Add a polymer monomer to a dispersion of uniformly sized nano templates, and polymer thin films are formed on the surfaces of the nano templates by monomer molecules.

[0010] Then add an appropriate amount of platinum salt to the above solution to obtain a mixed solution, stir and react for 0.5 - 30 h to obtain a reaction product.

[0011] Anneal the reaction product, and then remove the nano templates to obtain the platinum-carbon catalyst.

[0012] In the above solution, the nano templates are microemulsion droplets, oxide nanoparticles or bubble templates, and the particle size of the nano templates is 10 - 500 nm.

[0013] In the above solution, the microemulsion droplets are formed by uniformly stirring an oil phase, an aqueous phase and a surfactant.

[0014] Preferably, the used oil phase is any one or more of mesitylene, glycerol, n-hexane, toluene, the aqueous phase is a mixed solution of water and ethanol (1:(0.5 - 2)), the surfactant is any one or more of F127 (polyether), P123, SDS (with a mass ratio of 1:1 to the oil phase), and the volume ratio of the oil phase to the aqueous phase is 0.1 - 5:100.

[0015] In the above solution, the oxide nanoparticles are any one of ZnO, MgO, SnO2.

[0016] In the above solution, the bubble template is bubbles generated by stirring after mixing water with a water-soluble organic solvent, and the used water-soluble organic solvent is any one of methanol, ethanol, n-propanol, isopropanol.

[0017] Preferably, the volume ratio of the water-soluble organic solvent to water is 10:1.

[0018] In the above solution, the polymer monomer is any one of glucose, dopamine, pyridine, pyrrole, and aniline.

[0019] In the above solution, the concentration of the polymer monomer in the nano-template dispersion is 0.1 mM to 20 mM.

[0020] In the above solution, the concentration of platinum ions in the mixed solution is 0.01 to 0.5 M.

[0021] In the above solution, the annealing means centrifuging, washing, and drying the reaction product, and then annealing it in a non-oxidizing atmosphere at a temperature of 400 to 1200 °C for 1 to 6 hours, and taking it out after natural cooling.

[0022] In the above solution, the methods for removing the nano-template are as follows: the microemulsion droplets can be removed by ultrasonic washing with acetone and alcohol; the oxide nanoparticles can be etched and washed away with NaOH or HCl.

[0023] The particle size of the platinum-carbon catalyst is 100 - 600 nm. The Pt nanoparticles are uniformly loaded on the hollow carbon spheres. The particle size of the Pt particles is 4 - 9 nm, and the carbon layer thickness of the hollow carbon spheres is 10 - 30 nm.

[0024] The principle of the present invention is:

[0025] The present invention uses the template method to prepare a template with uniform size and small particle size. A polymer monomer is added to the nano-template dispersion, and appropriate conditions are controlled to form a polymer film on the surface of the nano-template by monomer molecules. Then, the polymer itself is used to reduce platinum ions to load platinum on the polymer; the product is annealed to obtain a platinum-carbon catalyst, and then the template is removed by washing or etching to obtain a hollow structure; the performance of the platinum-carbon catalyst is controlled by regulating the size of the hollow nano-carbon spheres, the concentration of platinum ions, and the temperature and time of annealing. The platinum-carbon catalyst obtained by the present invention uses a hollow nano-carbon sphere as a carrier, and the hollow structure provides a larger specific surface area; and the hollow structure significantly reduces the density of the platinum-carbon catalyst, making the platinum-carbon catalyst suspension have good dispersibility; and the polymer used has reducibility itself to reduce platinum ions, and no other reducing agents need to be added, avoiding the pollution of other reducing agents to the catalyst. The obtained catalyst has good electrochemical activity and exhibits excellent electrocatalytic hydrogen evolution performance and oxygen reduction performance; and the involved preparation method is simple and reliable.

[0026] Compared with the prior art, the present invention has the following positive effects:

[0027] The present invention prepares hollow carriers with uniform size and small particle size by a simple template method, which have a larger specific surface area, can better contact with the electrolyte, fully exert the activity of the platinum catalyst, and improve the atomic utilization rate; it also enables the platinum-carbon catalyst to have more active sites, thus enhancing its performance; at the same time, the hollow structure significantly reduces the density of the platinum-carbon catalyst, making the dispersibility of the catalyst suspension better than that of the commercial platinum-carbon catalyst, not easily sedimenting, and having good application prospects in fields such as membrane electrode preparation.

[0028] The hollow nanopolymer used in the present invention has its own reducibility and can reduce platinum ions without adding other reducing agents, avoiding the pollution of the catalyst by other reducing agents, and the platinum reduced by this method is not easily agglomerated, achieving the formation of platinum particles with small particle size and uniform dispersion on the hollow nanocarbon spheres;

[0029] The present invention further regulates the performance of the platinum-carbon catalyst by the size of the hollow nanocarbon spheres, the concentration of platinum ions, the annealing temperature and time, thereby realizing the controllable adjustment of the platinum-carbon catalyst and achieving good hydrogen evolution performance and oxygen reduction performance;

[0030] The preparation method involved in the present invention is simple and reliable, applicable to the preparation of electrocatalytic hydrogen evolution electrodes and oxygen reduction electrodes, and has good application prospects in fields such as proton exchange membrane electrolyzers and hydrogen fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0032] Figure 1 It is the scanning electron microscope image of the platinum-carbon catalyst obtained in Example 11 of the present invention;

[0033] Figure 2 It is the scanning electron microscope image of the platinum-carbon catalyst obtained in Example 1 of the present invention;

[0034] Figure 3 It is the high-resolution transmission electron microscope image of the platinum-carbon catalyst obtained in Example 1 of the present invention;

[0035] Figure 4 It is the hydrogen evolution reaction activity result diagram of the platinum-carbon catalyst obtained by annealing the product of Example 1 of the present invention at different temperatures for 3 h and the 20% commercial Pt / C catalyst in a 0.5 M H2SO4 solution;

[0036] Figure 5 It is the comparison of the dispersibility in water of the platinum-carbon catalyst (right) obtained in Example 1 of the present invention and the commercial platinum-carbon catalyst (left), and the comparison after ultrasonic dispersion in water and standing for 3 months. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] To avoid repetition, the template fabrication removal and annealing processes involved in this specific embodiment are described uniformly as follows and will not be elaborated in the following specific embodiments:

[0039] The nano-droplet template is formed by stirring an oil phase, an aqueous phase, and a surfactant evenly in appropriate proportions; the oil phase used is any one or more of mesitylene, glycerol, n-hexane, and toluene, the aqueous phase is a mixed solution of water and ethanol (1:(0.5 - 2)), the surfactant is any one or more of F127 (polyether), P123, and SDS (mass ratio to the oil phase 1:1), and the volume ratio of the oil phase is 0.1% - 5%. Among them, the volume ratio of the oil phase to the aqueous phase is 0.5 - 5:100.

[0040] The annealing refers to centrifuging the product obtained after reacting with the platinum solution, washing it with water and ethanol, drying it in an oven, then placing it in a tube furnace, annealing it at a temperature of 400 - 1200 °C for 1 - 6 hours in a non-oxidizing atmosphere, and taking it out after natural cooling.

[0041] The methods for removing the template are as follows: the microemulsion droplets are removed by ultrasonic washing with acetone and alcohol (1:1) for 20 - 30 min; the oxide nanoparticles are etched away with 2M NaOH or HCl.

[0042] Example 1

[0043] A platinum-carbon catalyst supported on hollow nano-carbon spheres, and its preparation method includes the following steps:

[0044] Add dopamine (DA) to the MgO dispersion to make the concentration of dopamine in the MgO dispersion 8 mM, stir for 24 h to polymerize dopamine on the template, then add chloroplatinic acid solution to the solution to obtain a mixed solution, the concentration of platinum ions in the mixed solution is 0.01 M, stir for 24 h to obtain MgO@PDA / Pt NP. Centrifuge the product, wash it alternately with water and ethanol and then dry it in an oven; then place it in a tube furnace, set the temperature to 1000 °C (subsequently prepared at different carbonization temperatures of 700 °C, 800 °C, 900 °C, and 1100 °C), anneal it for 3 h in a nitrogen atmosphere, and finally etch away the MgO template with 2M HCl to obtain a platinum-carbon catalyst supported on hollow nano-carbon spheres.

[0045] Example 2

[0046] A platinum-carbon catalyst supported on hollow nano-carbon spheres, and its preparation method includes the following steps:

[0047] Glucose was added to the ZnO dispersion to make the glucose concentration in the ZnO dispersion 0.1 mM, and stirred for 20 h to polymerize glucose on the template. Then, a platinum acetate solution was added to the solution to obtain a mixed solution, and the platinum ion concentration in the mixed solution was 0.3 M. After stirring for 0.5 h, ZnO@polyg lucose / Pt NP was obtained. The product was centrifuged, washed alternately with water and ethanol, and then placed in an oven for drying. Then, it was placed in a tubular furnace, the temperature was set to 700 °C, and annealed for 4 h in an argon atmosphere. Finally, the ZnO template was etched away with 2 M NaOH to obtain a platinum-carbon catalyst with hollow carbon nanospheres as the carrier.

[0048] Example 3

[0049] A platinum-carbon catalyst with hollow carbon nanospheres as the carrier, and its preparation method includes the following steps:

[0050] Pyridine was added to the SnO2 dispersion to make the pyridine concentration in the SnO2 dispersion 2 mM, and stirred for 16 h to carry out the polymerization reaction of pyridine on the template. Then, a platinum dichloride solution was added to the solution to obtain a mixed solution, and the platinum ion concentration in the mixed solution was 0.1 M. After stirring for 3 h, SnO2@polypyridine / Pt NP was obtained. The product was centrifuged, washed alternately with water and ethanol, and then placed in an oven for drying. Then, it was placed in a tubular furnace, the temperature was set to 900 °C, and annealed for 3 h in a helium atmosphere. Finally, the SnO2 template was etched away with 2 M HCl to obtain a platinum-carbon catalyst with a hollow polymer as the carrier.

[0051] Example 4

[0052] A platinum-carbon catalyst with hollow carbon nanospheres as the carrier, and its preparation method includes the following steps:

[0053] Pyrrole was added to the MgO dispersion to make the pyrrole concentration in the dispersion 4 mM, and stirred for 28 h to polymerize pyrrole on the template. Then, a platinum-containing solution (composed of platinum acetate and platinum tetrachloride in a molar ratio of 1:1) was added to the solution to obtain a mixed solution, and the platinum ion concentration in the mixed solution was 0.4 M. After stirring for 6 h, MgO@polypyrrole / Pt NP was obtained. The product was centrifuged, washed alternately with water and ethanol, and then placed in an oven for drying. Then, it was placed in a tubular furnace, the temperature was set to 1000 °C, and annealed for 4 h in a hydrogen atmosphere. Finally, the MgO template was etched away with 2 M HCl to obtain a platinum-carbon catalyst with hollow carbon nanospheres as the carrier.

[0054] Example 5

[0055] A platinum-carbon catalyst with hollow carbon nanospheres as the carrier, and its preparation method includes the following steps:

[0056] Add methanol to water (the volume ratio of water to methanol is 10:1), stir for 3 - 6 minutes, then add aniline to the solution to make the aniline concentration 18 mM, stir for 50 min to polymerize aniline on the template, and then add platinum(IV) chloride solution to the solution to obtain a mixed solution. The concentration of platinum ions in the mixed solution is 0.2 M, stir for 9 h to obtain polyaniline / Pt NPs. Centrifuge the product, wash it alternately with water and ethanol, and then place it in an oven for drying; then put it into a tube furnace, set the temperature to 1100 °C, and anneal it for 3 h in a nitrogen atmosphere to obtain a platinum-carbon catalyst supported on hollow nanocarbon spheres.

[0057] Example 6

[0058] A platinum-carbon catalyst supported on hollow nanocarbon spheres, and its preparation method includes the following steps:

[0059] Add ethanol to water (the volume ratio of water to ethanol is 10:1), stir for 3 - 6 minutes, then add pyridine to the solution to make the pyridine concentration 6 mM, stir for 50 min to polymerize pyridine on the template, and then add chloroplatinic acid solution to the solution to obtain a mixed solution. Make the concentration of platinum ions in the mixed solution 0.01 M, stir for 12 h to obtain polypyridine / Pt NPs. Centrifuge the product, wash it alternately with water and ethanol, and then place it in an oven for drying; then put it into a tube furnace, set the temperature to 1200 °C, and anneal it for 3 h in an argon atmosphere to obtain a platinum-carbon catalyst supported on hollow nanocarbon spheres.

[0060] Example 7

[0061] A platinum-carbon catalyst supported on hollow nanocarbon spheres, and its preparation method includes the following steps:

[0062] Add isopropanol to water (the volume ratio of water to isopropanol is 10:1), stir for 3 - 6 minutes, then add dopamine to the solution to make the dopamine concentration 10 mM, stir for 50 min to polymerize dopamine on the template, and then add platinum nitrate solution to the solution to obtain a mixed solution. Make the concentration of platinum ions in the mixed solution 0.1 M, stir for 15 h to obtain PDA / Pt NPs. Centrifuge the product, wash it alternately with water and ethanol, and then place it in an oven for drying; then put it into a tube furnace, set the temperature to 1200 °C, and anneal it for 1 h in a helium atmosphere to obtain a platinum-carbon catalyst supported on hollow nanocarbon spheres.

[0063] Example 8

[0064] A platinum-carbon catalyst supported on hollow nanocarbon spheres, and its preparation method includes the following steps:

[0065] Add n-propanol to water (the volume ratio of water to n-propanol is 10:1), stir for 3 - 6 minutes, then add pyrrole to the solution to make the concentration of pyrrole 12 mM, stir for 50 min to polymerize pyrrole on the template, and then add chloroplatinic acid solution to the solution to obtain a mixed solution, so that the concentration of platinum ions in the mixed solution is 0.2 M, stir for 18 h to obtain polypyrrole / Pt NP. Centrifuge the product, wash it alternately with water and ethanol, and then put it in an oven to dry; then put it into a tube furnace, set the temperature to 800 °C, and anneal it in a hydrogen atmosphere for 5 h to obtain a platinum-carbon catalyst supported by hollow nanocarbon spheres.

[0066] Example 9

[0067] A platinum-carbon catalyst supported by hollow nanocarbon spheres, and its preparation method includes the following steps:

[0068] Add aniline to the MgO dispersion, the concentration of aniline in the dispersion is 14 mM, stir for 16 h to polymerize aniline on the template, and then add platinum acetate solution to the solution to obtain a mixed solution, so that the concentration of platinum ions in the mixed solution is 0.3 M, stir for 21 h to obtain MgO@polyaniline / Pt NP. Centrifuge the product, wash it alternately with water and ethanol, and then put it in an oven to dry; then put it into a tube furnace, set the temperature to 900 °C, anneal it in a nitrogen atmosphere for 3 h, and finally etch away the MgO template with 2 M HCl to obtain a platinum-carbon catalyst supported by hollow nanocarbon spheres.

[0069] Example 10

[0070] A platinum-carbon catalyst supported by hollow nanocarbon spheres, and its preparation method includes the following steps:

[0071] Add glucose to the ZnO dispersion, the concentration of glucose in the dispersion is 16 mM, stir for 28 h to polymerize glucose, and then add chloroplatinic acid solution to the solution to obtain a mixed solution, so that the concentration of platinum ions in the mixed solution is 0.4 M, stir for 30 h to obtain ZnO@polyglycose / Pt NP. Centrifuge the product, wash it alternately with water and ethanol, and then put it in an oven to dry; then put it into a tube furnace, set the temperature to 1000 °C, anneal it in an argon atmosphere for 4 h, and finally etch away the ZnO template with 2 M NaOH to obtain a platinum-carbon catalyst supported by hollow nanocarbon spheres.

[0072] Example 11

[0073] A platinum-carbon catalyst supported by hollow nanocarbon spheres, and its preparation method includes the following steps:

[0074] 1) Use 1,3,5-trimethylbenzene as the oil phase with a volume fraction of 0.5% (relative to the aqueous phase), water and ethanol (1:1) as the aqueous phase. After mixing the aqueous and oil phases, add F127 (mass ratio to the oil phase is 1:1), and stir for 30 min to form a microemulsion;

[0075] 2) Add dopamine (DA) to the above microemulsion to make the DA concentration in the microemulsion 8 mM. Stir for 24 h to allow DA to self-polymerize on the template to obtain PDA. Remove the template by washing. Then add chloroplatinic acid solution to PDA to obtain a mixed solution with a platinum ion concentration of 0.1 M in the mixed solution. Stir and react for 24 h to obtain Pt / PDA nanospheres. Wash the product alternately with water and ethanol, dry it in an oven, and then anneal it in a tube furnace under a nitrogen atmosphere at an annealing temperature of 800 °C for 3 h to obtain a platinum-carbon catalyst supported on hollow nanocarbon spheres.

[0076] Example 12

[0077] A platinum-carbon catalyst supported on hollow nanocarbon spheres, and its preparation method includes the following steps:

[0078] 1) Use toluene as the oil phase with a volume fraction of 1% (relative to the aqueous phase), water and ethanol (1:1) as the aqueous phase. After mixing the aqueous and oil phases, add P123 (mass ratio to the oil phase is 1:1), and stir for 30 min to form a microemulsion;

[0079] 2) Add glucose to the above microemulsion to make the glucose concentration in the microemulsion 0.1 mM. Stir for 20 h to allow glucose to polymerize on the template to obtain polyglucose. Remove the template by washing. Then add platinum dichloride solution to the polymer solution to obtain a mixed solution with a platinum ion concentration of 0.2 M in the mixed solution. Stir and react for 0.5 h to obtain Pt / polymer nanospheres. Wash the product alternately with water and ethanol, dry it in an oven, and then anneal it in a tube furnace under an argon atmosphere at an annealing temperature of 400 °C for 2 h to obtain a platinum-carbon catalyst supported on hollow nanocarbon spheres.

[0080] Example 13

[0081] A platinum-carbon catalyst supported on hollow nanocarbon spheres, and its preparation method includes the following steps:

[0082] 1) Use ethylene glycol as the oil phase with a volume fraction of 2% (relative to the aqueous phase), water and ethanol (1:0.5) as the aqueous phase. After mixing the aqueous and oil phases, add SDS (mass ratio to the oil phase is 1:1), and stir for 30 min to form a microemulsion;

[0083] 2) Pyridine was added to the above microemulsion to make the concentration of pyridine in the microemulsion 2 mM, and stirred for 16 h to polymerize pyridine on the template to obtain a pyridine polymer. The template was removed by washing. Then, a platinum-containing solution (composed of chloroplatinic acid and platinum dichloride in a molar ratio of 1:1) was added to the polymer solution to obtain a mixed solution, so that the concentration of platinum ions in the mixed solution was 0.3 M. After stirring and reacting for 3 h, Pt / polymer nanospheres were obtained. The product was washed alternately with water and ethanol, dried in an oven, and then annealed in a tube furnace under a helium atmosphere at an annealing temperature of 600 °C for 5 h to obtain a platinum-carbon catalyst supported on hollow carbon nanospheres.

[0084] Example 14

[0085] A platinum-carbon catalyst supported on hollow carbon nanospheres, and its preparation method includes the following steps:

[0086] 1) Glycerol was used as the oil phase with a volume fraction of 3% (relative to the aqueous phase), water and ethanol (1:0.6) were used as the aqueous phase. After mixing the aqueous phase and the oil phase, F127 (mass ratio to the oil phase 1:1) was added, and stirred for 30 min to form a microemulsion;

[0087] 2) Pyrrole was added to the above microemulsion to make the concentration of pyridine in the microemulsion 4 mM, and stirred for 28 h to self-polymerize pyrrole on the template to obtain polypyrrole. The template was removed by washing. Then, a platinum tetrachloride solution was added to the polymer solution to obtain a mixed solution, so that the concentration of platinum ions in the mixed solution was 0.4 M. After stirring and reacting for 6 h, Pt / polypyrrole nanospheres were obtained. The product was washed alternately with water and ethanol, dried in an oven, and then annealed in a tube furnace under a hydrogen atmosphere at an annealing temperature of 700 °C for 4 h to obtain a platinum-carbon catalyst supported on hollow carbon nanospheres.

[0088] Example 15

[0089] A platinum-carbon catalyst supported on hollow carbon nanospheres, and its preparation method includes the following steps:

[0090] 1) Toluene and glycerol were used as the oil phase (volume ratio 1:1) with a volume fraction of 4% (relative to the aqueous phase), water and ethanol (1:1) were used as the aqueous phase. After mixing the aqueous phase and the oil phase, P123 (mass ratio to the oil phase 1:1) was added, and stirred for 30 min to form a microemulsion;

[0091] 2) Add aniline to the above microemulsion to make the concentration of aniline in the microemulsion 18 mM, stir for 30 h to polymerize aniline on the template to obtain polyaniline, remove the template by washing, then add a platinum-containing solution (composed of platinum tetrachloride and platinum dichloride in a molar ratio of 1:1) to the polymer solution to obtain a mixed solution, make the concentration of platinum ions in the mixed solution 0.5 M, stir and react for 9 h to obtain Pt / polyaniline nanospheres, wash the product alternately with water and ethanol, dry it in an oven and then put it into a tube furnace to anneal under a nitrogen atmosphere, the annealing temperature is 900 °C, and the annealing time is 3 h to obtain a platinum-carbon catalyst with hollow nanocarbon spheres as the carrier.

[0092] Example 16

[0093] A platinum-carbon catalyst with hollow nanocarbon spheres as the carrier, and its preparation method includes the following steps:

[0094] 1) Use 1,3,5-trimethylbenzene and glycerol as the oil phase (volume ratio 1:1), with a volume fraction of 3.5% (relative to the water phase), water and ethanol (1:1) as the water phase. After mixing the water phase and the oil phase, add SDS (mass ratio to the oil phase 1:1), and stir for 30 min to form a microemulsion;

[0095] 2) Add pyridine to the above microemulsion to make the concentration of pyridine in the microemulsion 6 mM, stir for 20 h to polymerize pyridine on the template, remove the template by washing, then add a platinum nitrate solution to the polymer solution to obtain a mixed solution, make the concentration of platinum ions in the mixed solution 0.05 M, stir and react for 12 h to obtain Pt / polypyridine nanospheres, wash the product alternately with water and ethanol, dry it in an oven and then put it into a tube furnace to anneal under an argon atmosphere, the annealing temperature is 1000 °C, and the annealing time is 2 h to obtain a platinum-carbon catalyst with hollow nanocarbon spheres as the carrier.

[0096] Example 17

[0097] A platinum-carbon catalyst with hollow nanocarbon spheres as the carrier, and its preparation method includes the following steps:

[0098] 1) Use toluene and ethylene glycol as the oil phase (volume ratio 1:1), with a volume fraction of 0.5% (relative to the water phase), water and ethanol (1:1) as the water phase. After mixing the water phase and the oil phase, add F127 (mass ratio to the oil phase 1:1), and stir for 30 min to form a microemulsion;

[0099] 2) Add DA to the above microemulsion to make the concentration of DA in the microemulsion 10 mM, stir for 30 h to self-polymerize DA on the template to obtain PDA, remove the template by washing, then add chloroplatinic acid solution to the PDA solution to obtain a mixed solution, make the concentration of platinum ions in the mixed solution 0.2 M, stir and react for 15 h to obtain Pt / PDA nanospheres, wash the product alternately with water and ethanol, dry it in an oven and then put it into a tube furnace for annealing under a helium atmosphere, the annealing temperature is 1100 °C, and the annealing time is 2 h to obtain a platinum-carbon catalyst with hollow nanocarbon spheres as the carrier.

[0100] Example 18

[0101] A platinum-carbon catalyst with hollow nanocarbon spheres as the carrier, and its preparation method includes the following steps:

[0102] 1) Use 1,3,5-trimethylbenzene and ethylene glycol as the oil phase (volume ratio 1:1), with a volume fraction of 5% (relative to the water phase), water and ethanol (1:1.2) as the water phase. After mixing the water phase and the oil phase, add P123 (mass ratio to the oil phase 1:1), and stir for 30 min to form a microemulsion;

[0103] 2) Add pyrrole to the above microemulsion to make the concentration of pyridine in the microemulsion 12 mM, stir for 24 h to polymerize pyrrole on the template, remove the template by washing, then add platinum acetate solution to the polymer solution to obtain a mixed solution, make the concentration of platinum ions in the mixed solution 0.3 M, stir and react for 14 h to obtain Pt / polypyrrole nanospheres, wash the product alternately with water and ethanol, dry it in an oven and then put it into a tube furnace for annealing under a hydrogen atmosphere, the annealing temperature is 1200 °C, and the annealing time is 6 h to obtain a platinum-carbon catalyst with hollow nanocarbon spheres as the carrier.

[0104] Example 19

[0105] A platinum-carbon catalyst with hollow nanocarbon spheres as the carrier, and its preparation method includes the following steps:

[0106] 1) Use a mixed solution of toluene, glycerol and ethylene glycol as the oil phase (volume ratio 1:1:1), with a volume fraction of 2% (relative to the water phase), water and ethanol (1:1.5) as the water phase. After mixing the water phase and the oil phase, add SDS (mass ratio to the oil phase 1:1), and stir for 30 min to form a microemulsion;

[0107] 2) Add aniline to the above microemulsion to make the concentration of aniline in the microemulsion 14 mM, stir for 12 h to polymerize aniline on the template, remove the template by washing, then add a platinum-containing solution (composed of chloroplatinic acid and platinum acetate in a molar ratio of 1:1) to the polymer solution to obtain a mixed solution, make the concentration of platinum ions in the mixed solution 0.2 M, stir and react for 21 h to obtain Pt / polyaniline nanospheres, wash the product alternately with water and ethanol, dry it in an oven and then put it into a tube furnace for annealing under a nitrogen atmosphere, with an annealing temperature of 800 °C and an annealing time of 5 h, to obtain a platinum-carbon catalyst supported by hollow nanocarbon spheres.

[0108] Example 20

[0109] A platinum-carbon catalyst supported by hollow nanocarbon spheres, and its preparation method includes the following steps:

[0110] 1) Use a mixed solution of 1,3,5-trimethylbenzene, glycerol and toluene as the oil phase (volume ratio 1:1:1), with a volume fraction of 1% (relative to the water phase), use water and ethanol (1:1.6) as the water phase, add F127 (mass ratio to the oil phase 1:1) after mixing the water phase and the oil phase, and stir for 30 min to form a microemulsion;

[0111] 2) Add glucose to the above microemulsion to make the concentration of glucose in the microemulsion 16 mM, stir for 26 h to polymerize glucose on the template, remove the template by washing, then add a platinum tetrachloride solution to the polymer solution to obtain a mixed solution, make the concentration of platinum ions in the mixed solution 0.5 M, stir and react for 20 h to obtain Pt / polyglycose nanospheres, wash the product alternately with water and ethanol, dry it in an oven and then put it into a tube furnace for annealing under an argon atmosphere, with an annealing temperature of 500 °C and an annealing time of 4 h, to obtain a platinum-carbon catalyst supported by hollow nanocarbon spheres.

[0112] Figure 1 SEM image of the platinum-carbon catalyst obtained in Example 11 of the present invention; it can be seen from the figure that we have prepared a nano platinum-carbon catalyst with uniform size and a diameter of about 500 nm.

[0113] Figure 2 SEM image of the platinum-carbon catalyst obtained in Example 1 of the present invention; it can be seen from the figure that we have prepared a nano platinum-carbon catalyst with uniform size and a diameter of about 200 nm.

[0114] Figure 3 TEM image of the platinum-carbon catalyst obtained in Example 1 of the present invention; it can be seen from the figure that the prepared Pt nanoparticles are uniformly loaded on the hollow carbon spheres, the particle size of the Pt particles is 4 - 9 nm, the carbon layer thickness of the hollow carrier is 18 nm, and it can also be obtained from the figure that the crystal plane with a lattice spacing of 0.23 nm comes from the (111) crystal plane of Pt.

[0115] Figure 4 The hydrogen evolution reaction activity results of the platinum-carbon catalyst obtained by annealing the product of Example 1 of the present invention at different temperatures for 3 hours and a 20% commercial Pt / C catalyst in a 0.5M H2SO4 solution; from the figure, we can see that the performance of the Pt / C catalyst carbonized at 1000°C is the best, superior to the 20% commercial Pt / C catalyst and the platinum-carbon catalysts carbonized at other temperatures.

[0116] Figure 5 Comparison of the dispersibility in water of the platinum-carbon catalyst obtained in Example 1 of the present invention (right) and the commercial platinum-carbon catalyst (left). After ultrasonic dispersion in water and standing for 3 months, it can be seen that the sedimentation phenomenon of the commercial platinum-carbon catalyst is very serious after three months of placement, but there is no obvious sedimentation phenomenon for the platinum-carbon catalyst with hollow carbon spheres as the carrier after standing for 3 months, and it is still evenly dispersed in water.

[0117] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a platinum-carbon catalyst with hollow carbon nanospheres as a carrier, characterized in that, It includes the following steps: Adding a polymer monomer to a dispersion of uniformly sized nano-templates, and forming a polymer film on the surface of the nano-templates by monomer molecules; Then adding an appropriate amount of platinum salt to the above solution to obtain a mixed solution, stirring and reacting for 0.5 - 30 h to obtain a reaction product; annealing the reaction product, and then removing the nano-templates to obtain the platinum-carbon catalyst.

2. The preparation method of the platinum-carbon catalyst using hollow nano-carbon spheres as a carrier according to claim 1, characterized in that, The nano-templates are microemulsion droplets, oxide nanoparticles or bubble templates, and the particle size of the nano-templates is 10 - 500 nm.

3. The preparation method of the platinum-carbon catalyst with hollow carbon nanospheres as the carrier according to claim 2, wherein, The microemulsion droplets are formed by uniformly stirring an oil phase, an aqueous phase and a surfactant.

4. The preparation method of the platinum-carbon catalyst with hollow carbon nanospheres as the carrier according to claim 2, characterized in that, The bubble template is bubbles generated by stirring after mixing water and a water-soluble organic solvent, and the water-soluble organic solvent used is any one of methanol, ethanol, n-propanol and isopropanol.

5. The preparation method of the platinum-carbon catalyst using hollow carbon nanospheres as a carrier according to claim 1, characterized in that, The polymer monomer is any one of glucose, dopamine, pyridine, pyrrole and aniline.

6. The preparation method of the platinum-carbon catalyst using hollow carbon nanospheres as a carrier according to claim 1, characterized in that, The concentration of the polymer monomer in the nano-template dispersion is 0.1 mM - 20 mM.

7. The preparation method of the platinum-carbon catalyst with hollow nano-carbon spheres as the carrier according to claim 1, characterized in that, The concentration of platinum ions in the mixed solution is 0.01 - 0.5 M.

8. The preparation method of the platinum-carbon catalyst with hollow nano-carbon spheres as the carrier according to claim 1, characterized in that, The annealing means centrifuging, washing and drying the reaction product, and then annealing at a temperature of 400 - 1200 °C for 1 - 6 hours in a non-oxidizing atmosphere, and taking it out after natural cooling.

9. A platinum-carbon catalyst with a hollow nano-carbon sphere as the carrier obtained by the preparation method according to any one of claims 1 to 8.

10. The platinum-carbon catalyst according to claim 9, characterized in that, The particle size of the platinum-carbon catalyst is 100 - 600 nm, the Pt nanoparticles are uniformly loaded on the hollow carbon sphere, the particle size of the Pt particles is 4 - 9 nm, and the carbon layer thickness of the hollow carbon sphere is 10 - 30 nm.

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