Sulfur-doped carbon-supported metal catalyst, and preparation method and application thereof

Abstract

The application relates to the technical fields of nanomaterial preparation and electrochemical energy conversion, and discloses a sulfur-doped carbon-supported metal catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: first ball milling treatment is performed on a carbon source and a sulfur source to obtain a sulfur-doped carbon material mixture; a metal precursor salt is added into the sulfur-doped carbon material mixture to perform second ball milling treatment, thereby obtaining a loaded precursor mixture; the loaded precursor mixture is dissolved in a solvent, the sulfur source not participating in the reaction is dissolved and removed, and after solid-liquid separation and drying, a catalyst precursor is obtained; the catalyst precursor is subjected to calcination treatment under a reducing atmosphere; the product obtained in step S4 is subjected to acid pickling treatment, and then low-temperature reduction treatment is performed, thereby obtaining the sulfur-doped carbon-supported metal catalyst. The catalyst exhibits excellent catalytic activity and stability in electrocatalytic oxygen reduction reaction and electrocatalytic hydrogen evolution reaction, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the fields of nanomaterial preparation and electrochemical energy conversion technology, and particularly to a sulfur-doped carbon-supported metal catalyst, its preparation method, and its application. Background Technology

[0002] Enhancing the interaction between metals and supports is not only useful for improving the electrocatalytic performance of catalysts, but has also attracted widespread attention in recent years for controlling the morphology and structure of metal sites, especially in the field of multivalent metal oxide supports such as TiO2, CeO2, V2O3, Nb2O5, and Ta2O5. Studies have shown that forming an oxide capping layer on the surface of noble metals can effectively suppress the migration of noble metal atoms, thereby improving their resistance to sintering and achieving nanoscale loading of metal sites. However, for graphitized carbon supports, due to their strong chemical inertness, they typically exhibit weak interactions with ligand-free metal species. Therefore, achieving nanoscale loading of metal sites on graphitized carbon supports under high-temperature conditions remains a significant challenge.

[0003] In existing technologies, N and O-doped carbon materials with high specific surface area have been widely used as ideal carbon supports for anchoring nanoscale metal sites. Recently, Liang Haiwei's team developed a series of novel sulfur-doped carbon supports, utilizing the strong bonding between sulfur and noble metals to effectively enhance the anti-sintering ability of noble metal nanoparticles, and successfully prepared a variety of highly dispersed and crystalline ordered carbon-supported noble metal catalysts. Although the above methods have made significant progress, the following technical problems still exist: the graphitization degree of carbon supports prepared by existing in-situ organic carbonization processes is low, the preparation process is complex, and it involves a variety of difficult-to-control process variables, resulting in poor stability and reproducibility of mass-produced high-quality carbon-supported metal catalysts.

[0004] Therefore, developing a simple, green, and scalable synthesis strategy to prepare carbon-supported noble metal catalysts with anti-sintering properties and high activity by enhancing the interaction between metals and supports is a technical challenge that urgently needs to be solved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a sulfur-doped carbon-supported metal catalyst, its preparation method and application, aiming to solve the defects of the prior art in preparing sulfur-doped carbon-supported metal catalysts by in-situ carbonization of organic matter, which is complex, difficult to scale up, and difficult to maintain the small size and high dispersion of metal nanoparticles at high temperature. The invention provides a simple and easily scaled-up method for preparing sulfur-doped carbon-supported noble metal and platinum-rich intermetallic compound catalysts.

[0006] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing a sulfur-doped carbon-supported metal catalyst, the method comprising the following steps: S1. The carbon source and sulfur source are subjected to a first ball milling process to obtain a sulfur-doped carbon material mixture; S2. The metal precursor salt is added to the sulfur-doped carbon material mixture for a second ball milling process to obtain a loaded precursor mixture. S3. Dissolve the supported precursor mixture in a solvent to dissolve and remove the unreacted sulfur source, and obtain the catalyst precursor after solid-liquid separation and drying. S4. The catalyst precursor is calcined under a reducing atmosphere; S5. The product obtained in step S4 is subjected to acid washing and then low-temperature reduction treatment to obtain the sulfur-doped carbon-supported metal catalyst.

[0007] Optionally, in step S1, the mass ratio of the carbon source to the sulfur source is 1:3-10; the carbon source is selected from one or more of expanded graphite, carbon nanotubes, graphene, and carbon black; and the sulfur source is selected from one or more of sulfur powder and sulfur-containing compounds.

[0008] Optionally, the rotation speed of the first ball milling process and the second ball milling process are each independently 300 to 900 rpm, and the processing time is each independently 3 to 7 hours.

[0009] Optionally, the metal precursor salt includes noble metal salts and transition metal salts; the noble metal element in the noble metal salt is selected from one or more of platinum (Pt), palladium (Pd), iridium (Ir), ruthenium (Ru), rhodium (Rh), gold (Au), and silver (Ag); the transition metal element in the transition metal salt is selected from one or more of iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), manganese (Mn), and zinc (Zn).

[0010] Optionally, in step S3, the solvent is one of carbon disulfide, carbon tetrachloride, and benzene.

[0011] Optionally, in step S4, the calcination treatment is carried out at a temperature of 600℃-1000℃ for 1 to 5 hours; the reducing atmosphere is a mixed atmosphere containing hydrogen.

[0012] Optionally, in step S5, the acid solution used in the pickling treatment is a sulfuric acid solution of 0.5 to 2 mol / L; the low-temperature reduction treatment is carried out in a reducing atmosphere containing hydrogen, at a temperature of 350°C to 450°C, for a time of 2 to 6 hours.

[0013] In a second aspect, the present invention provides a sulfur-doped carbon-supported metal catalyst, wherein the sulfur-doped carbon-supported metal catalyst is prepared by the above-described preparation method; The sulfur-doped carbon-supported metal catalyst includes a sulfur-doped carbon support and a metal species supported on the sulfur-doped carbon support, wherein the metal species includes noble metals.

[0014] Optionally, the metal species is an intermetallic compound.

[0015] Optionally, the intermetallic compound is a platinum-rich intermetallic compound.

[0016] In a third aspect, the present invention provides the application of the above-described sulfur-doped carbon-supported metal catalyst as an electrocatalyst in electrocatalytic reactions.

[0017] Optionally, the electrocatalytic reaction is an electrocatalytic oxygen reduction reaction (ORR) or an electrocatalytic hydrogen evolution reaction (HER), or other chemical electrocatalytic reactions.

[0018] The present invention has the following beneficial effects: The preparation method of this invention uses a dry ball milling process to directly mix carbon source, sulfur source and metal precursor salt. The target catalyst can be obtained through simple subsequent solvent cleaning, high-temperature calcination and post-treatment steps. The whole process is simple, with few variables, avoiding the complex organic precursor synthesis and carbonization process, and is easy to achieve large-scale production. It effectively solves the problems of complex processes and difficulty in mass production in the existing technology.

[0019] The preparation method involves ball milling, utilizing the similar electronegativity of sulfur and carbon atoms to generate strong chemical forces between them, sufficient to disrupt the π-π interactions between graphite layers. This not only achieves the exfoliation of the carbon source (such as expanded graphite) and the simultaneous doping of sulfur atoms, but also ensures uniform mixing of the metal precursor and the sulfur-doped carbon material. During the subsequent high-temperature pyrolysis process, strong electron-metal-carrier interactions are formed between the sulfur atoms in the support and the metal atoms. This interaction effectively anchors the metal atoms, inhibiting their migration and aggregation at high temperatures. Thus, metal nanoparticles with an average particle size of less than 5 nm, which can be uniformly dispersed even under high loading, can be obtained without the need for complex organic templates or confined structures.

[0020] Because the metal nanoparticles in the catalyst are small in size and uniformly dispersed, and because sulfur doping in the support enhances the metal-support interaction, the catalyst exposes more active sites and exhibits superior stability in electrocatalytic reactions. Therefore, this catalyst demonstrates excellent catalytic activity and stability in both electrocatalytic oxygen reduction and electrocatalytic hydrogen evolution reactions, showing broad application prospects. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the preparation process and mechanism of sulfur-doped carbon-supported metal catalysts.

[0022] Figure 2 Transmission electron microscopy (TEM) images of the Pt3Fe / SG catalyst prepared in Example 1 and the corresponding particle size distribution of the metal nanoparticles. (a) Low-magnification TEM image; (b) HAADF-STEM image, with embedded particle size distribution from 200 Pt3Fe nanoparticles; (c) HRTEM image.

[0023] Figure 3 X-ray diffraction (XRD) pattern and high-angle annular dark-field transmission electron microscopy (HAADF-STEM) image of the Pt3Fe / SG catalyst prepared in Example 1. (a) XRD pattern; (b) AC-HAADF-STEM image and corresponding elemental distributions of S, Pt, and Fe; (c, d) AC-HAADF-STEM images; (e) SEM images of Pt and Fe atoms in selected regions of image d.

[0024] Figure 4 TEM images and corresponding particle size distributions of the high metal loading Pt3Fe / SG catalyst prepared in Example 2. (a) XRD pattern; (b, c, e) Low-magnification TEM images; (d) Statistical particle size distribution of 200 Pt3Fe nanoparticles; (f) High-magnification TEM image.

[0025] Figure 5 TEM images of the SG-supported multi-component Pt-based intermetallic compound catalysts (Pt2FeCo / SG, Pt3FeCoNi / SG, Pt4FeCoNiCu / SG, Pt5FeCoNiMnCu / SG) prepared in Example 3. (ab) Pt2FeCo; (cd) Pt3FeCoNi; (ef) Pt4FeCoNiCu; (gh) Pt5FeCoNiMnCu.

[0026] Figure 6 TEM images of the Pt3Fe / S-CNT catalyst prepared in Example 4. (a, b) Low-magnification TEM, inset showing the particle size distribution from 200 nanoparticles; (c) High-magnification TEM; (d) HAADF-STEM image and EDS elemental distribution.

[0027] Figure 7 TEM images of the Pt3Fe / S-VC-72 catalyst prepared in Example 4. (a, b) Low-magnification TEM, inset showing the particle size distribution from 200 nanoparticles; (c) High-magnification TEM; (d) HAADF-STEM image and EDS elemental distribution.

[0028] Figure 8 TEM images and corresponding particle size distributions of the Pt / SG catalyst prepared in Example 5. (a) XRD; (b, c) Low-magnification TEM, inset of Figure c shows the particle size distribution from 200 nanoparticles; (d) HAADFS TEM image and EDS elemental distribution.

[0029] Figure 9 TEM images of the Pd / SG catalyst prepared in Example 5. (a) XRD; (b, c) Low-magnification TEM; (d) High-magnification TEM, with the inset showing a magnified HRTEM; (e) HAADF-STEM image and EDS elemental distribution.

[0030] Figure 10 TEM images of the Ir / SG catalyst prepared in Example 5. (a) XRD; (b, c) Low-magnification TEM, inset of (b) shows the particle size distribution from 200 nanoparticles; (d) High-magnification TEM, inset shows the magnified HRTEM; (e) HAADF-STEM image and EDS elemental distribution.

[0031] Figure 11 TEM images of the Pt3Fe / S-free-G catalyst prepared for Comparative Example 1. (a) Low-magnification TEM image; (b) Particle size distribution of 200 Pt3Fe nanoparticles.

[0032] Figure 12 Comparison of oxygen reduction reaction (ORR) polarization curves between Pt3Fe / SG catalyst and commercial Pt / C catalyst in 0.1 M KOH solution. (a) RDE polarization curves, with Tafel plots in the inset; (b) Different catalysts at 0.85 V. J k and E 1 / 2 Figure 13 The power density and discharge curves of a zinc-air battery assembled with Pt3Fe / SG as the air electrode catalyst are shown. (a) Open circuit potential; (b) Polarization curve and power density plot.

[0033] Figure 14 Comparison of hydrogen evolution reaction (HER) polarization curves of Pt3Fe / SG catalyst and commercial Pt / C catalyst in 0.5 M H2SO4 solution. (a) LSV curve; (b) Comparison of overpotentials at different current densities.

[0034] Figure 15Comparison of hydrogen evolution reaction (HER) polarization curves of Pt3Fe / SG catalyst and commercial Pt / C catalyst in 1.0 M PBS solution. (a) LSV curve; (b) Comparison of overpotentials at different current densities.

[0035] Figure 16 Comparison of hydrogen evolution reaction (HER) polarization curves of Pt3Fe / SG catalyst and commercial Pt / C catalyst in 1.0 M KOH solution. (a) LSV curve; (b) Comparison of overpotentials at different current densities. Detailed Implementation

[0036] This invention provides a sulfur-doped carbon-supported metal catalyst, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0037] This invention addresses the challenges of complex and scalable processes in the preparation of sulfur-doped carbon-supported metal catalysts via in-situ carbonization of organic matter, as well as the difficulty in maintaining the small size and high dispersion of metal nanoparticles at high temperatures. It provides a simple and universally applicable solution. The preparation method of this invention is particularly suitable for electrocatalytic energy conversion, such as oxygen reduction reaction (ORR) catalysts in fuel cells and metal-air batteries, and hydrogen evolution reaction (HER) catalysts in water electrolysis.

[0038] Based on this, embodiments of the present invention provide a method for preparing a sulfur-doped carbon-supported metal catalyst, the preparation method comprising the following steps: S1. The carbon source and sulfur source are subjected to a first ball milling process to obtain a sulfur-doped carbon material mixture; S2. The metal precursor salt is added to the sulfur-doped carbon material mixture for a second ball milling process to obtain a loaded precursor mixture. S3. Dissolve the supported precursor mixture in a solvent to dissolve and remove the unreacted sulfur source, and obtain the catalyst precursor after solid-liquid separation and drying. S4. The catalyst precursor is calcined under a reducing atmosphere; S5. The product obtained in step S4 is subjected to acid washing and then low-temperature reduction treatment to obtain the sulfur-doped carbon-supported metal catalyst.

[0039] In the preparation process, sulfur atoms are first doped into the carbon support framework through ball milling, activating the originally chemically inert highly graphitized carbon surface. Subsequently, during the high-temperature calcination stage, strong electronic metal-support interactions are formed between the doped sulfur atoms and metal atoms (especially noble metal atoms). This strong interaction acts as an "anchor," effectively inhibiting the migration and aggregation of metal atoms at high temperatures, thus obtaining metal nanoparticles with an average particle size of less than 5 nanometers (nm), uniform dispersion, and an ordered crystal structure. Even when the total metal loading is as high as 51 wt%, the nanoparticles still maintain a small size and uniform dispersion, solving the technical problem of easy aggregation under high loading, ultimately enabling the catalyst to exhibit excellent activity and stability in electrocatalytic reactions such as ORR and HER.

[0040] In some embodiments, in step S1, the mass ratio of the carbon source to the sulfur source is 1:3-10 (e.g., 1:3, 1:5, 1:6, 1:9, 1:10, etc.); the carbon source is selected from expanded graphite, carbon nanotubes, graphene, or carbon black. When expanded graphite is selected as the carbon source, in the ball milling process, sulfur powder not only acts as a dopant source but also as a physical exfoliating agent. Under the shear force of the ball mill jar, the sulfur powder peels off the expanded graphite layer by layer like "tape," simultaneously converting the expanded graphite into few-layer or multi-layer graphene and doping sulfur atoms into the carbon layers of the graphene, thereby efficiently preparing sulfur-doped graphene carriers. This process is simple, green, and easy to scale up for production. In addition to expanded graphite, the carbon source can also be carbon nanotubes, graphene, or carbon black. When using these carbon sources, the ball milling process mainly achieves mechanochemical doping of sulfur atoms, which can also effectively introduce sulfur into the carbon carrier and activate the carrier surface. Compared to using graphene or carbon black directly, using expanded graphite offers advantages such as lower raw material costs and the ability to simultaneously prepare the carrier and dope through a one-step ball milling process. The sulfur source is sulfur powder or a sulfur-containing compound. Sulfur powder is preferred because the sulfur atoms and carbon atoms in the sulfur molecule have similar electronegativity, resulting in strong chemical forces between them. Under ball milling, these forces are sufficient to disrupt the π-π interactions between graphite layers, thus achieving in-situ exfoliation of expanded graphite into two-dimensional multilayer graphene and simultaneously completing surface doping of sulfur atoms. This dry ball milling process involving sulfur powder does not generate waste liquid or wastewater, effectively reducing environmental costs. Furthermore, using carbon disulfide, which has a low boiling point, as the sulfur powder extractant significantly reduces the energy consumption of solvent distillation, and the extracted high-purity sulfur powder can be recycled, avoiding raw material waste and embodying the concept of green and environmentally friendly preparation.

[0041] In some preferred embodiments, the mass ratio of carbon source to sulfur source is 1:5, and the total mass ratio of carbon source to metal elements in metal precursor is [missing information]. This range enables flexible preparation of catalysts from low loading to ultra-high loading (e.g., 51 wt%).

[0042] In some embodiments, the rotational speed of the first and second ball milling processes is independently between 300 and 900 rpm, and the processing time is independently between 3 and 7 hours. The rotational speed of the first and second ball milling processes can be independently 300 rpm, 310 rpm, 320 rpm, 330 rpm, 340 rpm, 350 rpm, 360 rpm, 370 rpm, 380 rpm, 390 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm, or 900 rpm. The processing time can be independently 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, or 7 hours.

[0043] In some embodiments, the metal precursor salt includes a noble metal salt and a transition metal salt; the noble metal element in the noble metal salt is selected from one or more of platinum (Pt), palladium (Pd), iridium (Ir), ruthenium (Ru), rhodium (Rh), gold (Au), and silver (Ag); the transition metal element in the transition metal salt is selected from one or more of iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), manganese (Mn), and zinc (Zn). By adjusting the type and ratio of the noble metal salt and the transition metal salt, platinum-rich intermetallic compounds ranging from elemental noble metals to binary, ternary, and even more elemental compounds can be prepared. Intermetallic compounds have long-range ordered crystal structures, and their electronic structure and geometric effects are generally superior to disordered alloys, which can significantly enhance intrinsic catalytic activity. The amount of metal precursor salt added is determined according to the stoichiometric ratio of the metal elements in the target product.

[0044] In some embodiments, in step S3, the solvent is one of carbon disulfide, carbon tetrachloride, and benzene.

[0045] In some embodiments, in step S4, the calcination treatment temperature is 600℃-1000℃, and the time is 1 to 5 hours; the reducing atmosphere is a mixed atmosphere containing hydrogen. The calcination treatment temperature can be 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, or 1000℃, and the time can be 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours.

[0046] In some embodiments, in step S5, the acid solution used for pickling is a 0.5 to 2 mol / L sulfuric acid solution; the low-temperature reduction treatment is carried out in a reducing atmosphere containing hydrogen, at a temperature of 350°C to 450°C, for 2 to 6 hours. The concentration of the sulfuric acid can be 0.5 mol / L, 1 mol / L, 1.5 mol / L, or 2 mol / L; the low-temperature reduction treatment is carried out in a reducing atmosphere containing hydrogen, at a temperature of 350°C, 400°C, or 450°C, for 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours.

[0047] In some embodiments, a method for preparing the above-mentioned sulfur-doped carbon-supported noble metal and platinum-rich intermetallic compound catalyst is provided. For example... Figure 1 As shown, the method includes: Step 1.1 involves placing the carbon source and sulfur source in a ball mill jar for ball milling to obtain a mixed product. In this step, the ball milling speed is 300 to 900 revolutions per minute (r / min), and the processing time is 3 to 7 hours. This process utilizes mechanical force to achieve the exfoliation of carbon materials (for expanded graphite) and the initial doping of sulfur atoms.

[0048] Step 1.2: Add the metal precursor salt to the mixture obtained in Step 1.1 and continue ball milling to obtain a mixed powder loaded with the metal precursor. This ball milling process takes 3 to 8 hours. This step ensures that the metal precursor and the sulfur-doped carbon material are thoroughly and uniformly mixed, laying the foundation for the subsequent formation of uniform metal nanoparticles.

[0049] Step 1.3 involves dispersing the mixed powder obtained in Step 1.2 in a solvent with stirring to dissolve and remove excess sulfur powder. The resulting powder is then filtered and dried to obtain the precursor powder. The solvent is carbon disulfide (CS2) or other solvents capable of dissolving sulfur powder. This step washes away excess free sulfur, preventing its excessive volatilization during high-temperature calcination and ensuring a more uniform sulfur doping state.

[0050] Step 1.4: The precursor powder dried in Step 1.3 is subjected to high-temperature pyrolysis calcination under a reducing atmosphere to obtain carbon-supported metal nanoparticles. The reducing atmosphere is a mixed atmosphere containing hydrogen, such as a mixture of hydrogen and argon with a volume percentage of 5%. The high-temperature pyrolysis calcination temperature is 600℃ to 1000℃, and the calcination time is 1 to 5 hours. This high-temperature process induces the reduction, diffusion, and orderly arrangement of metal atoms to form intermetallic compounds. Simultaneously, strong electron-metal-carrier interactions are formed between the sulfur atoms doped in the support and the metal atoms, strongly anchoring the metal particles and inhibiting their high-temperature growth.

[0051] Step 1.5 involves acid washing the product obtained in Step 1.4 in an acid solution, followed by filtration and water washing. The product is then subjected to a low-temperature reduction treatment under a reducing atmosphere to obtain the target catalyst. The acid solution is a 0.5 to 2 mol / L sulfuric acid solution. The purpose of acid washing is to remove some metal oxides, amorphous carbon impurities, or unstable metal species that may be generated during calcination, thus purifying the catalyst surface. The low-temperature reduction treatment is carried out in a reducing atmosphere containing hydrogen at a temperature of 350°C to 450°C for 2 to 6 hours. This step aims to further reduce any metal surfaces that may have been oxidized after acid washing, ensuring that the active metal sites exist in a metallic state, thereby obtaining optimal catalytic activity.

[0052] This invention provides a sulfur-doped carbon-supported metal catalyst, which is prepared by the above-described preparation method. The sulfur-doped carbon-supported metal catalyst includes a sulfur-doped carbon support and a metal species supported on the sulfur-doped carbon support, wherein the metal species includes noble metals.

[0053] Optionally, the metal species is an intermetallic compound.

[0054] Optionally, the intermetallic compound is a platinum-rich intermetallic compound.

[0055] This invention provides the application of the sulfur-doped carbon-supported metal catalyst described above as an electrocatalyst in electrocatalytic reactions.

[0056] Preferably, sulfur-doped carbon-supported metal catalysts are used as electrocatalysts in electrocatalytic oxygen reduction reaction (ORR) or electrocatalytic hydrogen evolution reaction (HER).

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0058] The following detailed description uses specific examples.

[0059] Example 1: Preparation of Pt3Fe / SG catalyst (1) Place 0.5 g of expanded graphite and 3 g of sulfur powder into a ball mill jar and ball mill at 500 r / min for 4 hours; (2) Add platinum chloride and ferric chloride (total metal content about 20 wt%) according to the Pt:Fe stoichiometric ratio, and continue ball milling for 3 hours; (3) The product was dispersed and washed with carbon disulfide to remove excess sulfur powder, filtered and dried; (4) The dried powder was calcined at 750°C for 3 hours under a 5% H2 / Ar atmosphere; (5) The product was acid-washed with 0.5 M H2SO4 and then washed with water. It was then reduced at 400℃ in H2 / Ar atmosphere to obtain Pt3Fe / SG.

[0060] Phase morphology characterization: TEM analysis showed that the average particle size of the Pt3Fe nanoparticles was 3.62 nm, and XRD analysis revealed that they exhibited an ordered L12-Pt3Fe crystal structure. The phase morphology characterization is as follows: Figure 2-3 As shown.

[0061] Example 2: Preparation of Pt3Fe / SG with high metal loading The preparation steps are the same as in Example 1, except that the amount of metal salt added in step (2) is increased to make the theoretical metal loading reach 51 wt%.

[0062] Phase morphology characterization: Tests showed that even under high loading, the average particle size of Pt3Fe was only 3.81 nm, with no obvious large particle agglomeration observed. Figure 4 As shown.

[0063] Example 3: Preparation of S-G supported multi-component Pt-based intermetallic compound catalyst The preparation steps are the same as in Example 1, except that the metal precursor is replaced with chloride salts of Pt, Fe, Co, Ni, Cu, and Mn, and the amount of each metal salt is determined according to the stoichiometric ratio of each metal element in the target product.

[0064] Phase morphology characterization: The average particle sizes of the four platinum-rich -i-NPs, Pt2FeCo, Pt3FeCoNi, Pt4FeCoNiCu and Pt5FeCoNiMnCu, were 3.39, 3.99, 4.31 and 4.91 nm, respectively, with average sizes all less than 5 nm. Figure 5 As shown.

[0065] Example 4: Verification of different carbon supports The preparation steps are the same as in Example 1, except that the expanded graphite in Example 1 is replaced with carbon nanotubes (CNTs) and Vulcan XC-72 carbon black, respectively.

[0066] Phase morphology characterization: The average particle sizes of the synthesized Pt3Fe / S-CNT and Pt3Fe / S-VC-72 were 2.35 nm and 3.21 nm, respectively, verifying the universality of the method. Figure 6-7 As shown.

[0067] Example 5: Synthesis of S-G noble metal elemental nanoparticles The preparation steps are the same as in Example 1, except that the metal source is replaced with a single noble metal salt (metal loading of about 20 wt%).

[0068] Phase morphology characterization: The average particle sizes of the obtained Pt / SG, Pd / SG, and Ir / SG were 2.41 nm, 1.62 nm, and 2.18 nm, respectively. Figure 8-10 As shown.

[0069] Comparative Example 1: Pt3Fe / S-free-EG (sulfur-free doping) Without adding sulfur powder, expanded graphite and metal salt were directly mixed and ball-milled, and the subsequent steps were the same as in Example 1.

[0070] Phase morphology characterization: TEM showed severe agglomeration of metal particles, with an average particle size reaching 10.5 nm. Figure 11 As shown.

[0071] Performance testing Oxygen reduction (ORR) performance testing: Tested in 0.1 M KOH electrolyte. Results showed that the half-wave potential of Pt3Fe / SG was 0.928 V, superior to commercially available Pt / C (0.858 V). A zinc-air battery assembled using it as the cathode achieved a peak power density of 280 mW / cm². 2 ,like Figure 12-13 As shown.

[0072] Hydrogen evolution reaction (HER) performance was tested in 0.5 M H₂SO₄, 1.0 M PBS, and 1.0 M KOH. Results showed a HER rate of 10 mA / cm⁻¹. 2 The overpotentials at current densities were 11 mV, 38 mV, and 28 mV, respectively, all significantly better than those of commercial Pt / C. Figure 14-16 As shown.

[0073] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a sulfur-doped carbon-supported metal catalyst, characterized in that, The preparation method includes the following steps: S1. The carbon source and sulfur source are subjected to a first ball milling process to obtain a sulfur-doped carbon material mixture; S2. The metal precursor salt is added to the sulfur-doped carbon material mixture for a second ball milling process to obtain a loaded precursor mixture. S3. Dissolve the supported precursor mixture in a solvent to dissolve and remove the unreacted sulfur source, and obtain the catalyst precursor after solid-liquid separation and drying. S4. The catalyst precursor is calcined under a reducing atmosphere; S5. The product obtained in step S4 is subjected to acid washing and then low-temperature reduction treatment to obtain the sulfur-doped carbon-supported metal catalyst.

2. The method for preparing the sulfur-doped carbon-supported metal catalyst according to claim 1, characterized in that, In step S1, the mass ratio of the carbon source to the sulfur source is 1:3-10; the carbon source is selected from one or more of expanded graphite, carbon nanotubes, graphene and carbon black; the sulfur source is selected from one or more of sulfur powder and sulfur-containing compounds.

3. The method for preparing the sulfur-doped carbon-supported metal catalyst according to claim 1, characterized in that, The rotational speed of the first ball milling process and the second ball milling process are each independently between 300 and 900 rpm, and the processing time is each independently between 3 and 7 hours.

4. The method for preparing the sulfur-doped carbon-supported metal catalyst according to claim 1, characterized in that, The metal precursor salt includes noble metal salts and transition metal salts; the noble metal element in the noble metal salt is selected from one or more of platinum, palladium, iridium, ruthenium, rhodium, gold, and silver; the transition metal element in the transition metal salt is selected from one or more of iron, cobalt, nickel, copper, manganese, and zinc.

5. The method for preparing the sulfur-doped carbon-supported metal catalyst according to claim 1, characterized in that, In step S3, the solvent is one of carbon disulfide, carbon tetrachloride, and benzene.

6. The method for preparing the sulfur-doped carbon-supported metal catalyst according to claim 1, characterized in that, In step S4, the calcination treatment is carried out at a temperature of 600℃-1000℃ for 1 to 5 hours; the reducing atmosphere is a mixed atmosphere containing hydrogen.

7. The method for preparing the sulfur-doped carbon-supported metal catalyst according to claim 1, characterized in that, In step S5, the acid solution used in the pickling treatment is a sulfuric acid solution of 0.5 to 2 mol / L; the low-temperature reduction treatment is carried out in a reducing atmosphere containing hydrogen, at a temperature of 350°C to 450°C, for a time of 2 to 6 hours.

8. A sulfur-doped carbon-supported metal catalyst, characterized in that, The sulfur-doped carbon-supported metal catalyst was prepared using the above-described preparation method. The sulfur-doped carbon-supported metal catalyst includes a sulfur-doped carbon support and a metal species supported on the sulfur-doped carbon support, wherein the metal species includes noble metals.

9. The sulfur-doped carbon-supported metal catalyst according to claim 8, characterized in that, The metal species are intermetallic compounds.

10. The use of the sulfur-doped carbon-supported metal catalyst according to any one of claims 1-3 as an electrocatalyst in electrocatalytic reactions.

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