A porous carbon supported platinum metal nanomaterial and a preparation method and application thereof

Abstract

The application discloses a porous carbon loaded platinum metal nanomaterial and a preparation method and application thereof, and relates to the technical field of new energy materials.The method comprises the following steps: high-temperature annealing porous carbon is immersed in a mixed solution of a platinum salt and a transition metal salt, metal ions are adsorbed in carbon pores through ultrasonic treatment, and a metal salt / porous carbon composite is obtained by evaporating the solvent; carbon thermal reduction is carried out in a temperature range in which platinum and the transition metal are immiscible, platinum ions are reduced to zero-valence platinum atoms and nucleate and grow, transition metal ions are reduced to oxides, and carbon monoxide produced by reduction is constrained and guided to grow into two-dimensional sheet oxides in anisotropy; sheet interfaces inhibit the isotropic growth of Pt, so that Pt forms two-dimensional sheet nanomaterials; and the oxides are removed through acid washing, so that the porous carbon loaded Pt nanomaterial is obtained.The catalytic material is used as a cathode oxygen reduction catalyst of a proton exchange membrane fuel cell, and has super-high electrochemical area and catalytic activity and excellent durability under acidic conditions.

Description

Technical Field

[0001] This invention relates to a porous carbon-supported platinum metal nano-olefin catalytic material, its preparation method and application, belonging to the field of new energy materials technology. Background Technology

[0002] The oxygen reduction reaction (ORR) in proton exchange membrane fuel cells, the most important electrochemical energy conversion technology, is kinetic, requiring the use of platinum (Pt) as the main component of the catalyst to overcome its slow reaction kinetics. However, Pt resources are scarce, leading to the high cost of catalyst materials. Therefore, it is necessary to rationally design the composition and structure of Pt catalyst materials to improve their inherent activity and reduce the amount of Pt required. Currently, the most commonly used Pt catalyst material in fuel cells is the traditional carbon-supported Pt nanoparticles (NPs), namely Pt NPs / C catalysts. The main method to improve the catalytic activity and Pt utilization of Pt NPs / C catalysts is to reduce the particle size of Pt NPs. However, since Pt NPs are spherical particles formed by the isotropic growth of Pt atoms during the preparation of Pt NPs / C catalysts, even if the diameter of Pt NPs is reduced to about 2 nm, only the Pt atoms on the outer layer of the spherical particles participate in the catalytic reaction, while a large number of Pt atoms inside the sphere cannot be exposed to the reaction interface, resulting in a Pt atom utilization rate of only 20-30%. Therefore, only by innovating the nanostructure of Pt catalytic materials and increasing the atomic utilization rate of Pt catalysts to over 50% can we meet the needs of large-scale application of energy conversion and storage technologies.

[0003] In recent years, two-dimensional materials (also known as metallenes) with close-packed and highly symmetric crystal structures composed of one or several layers of metal atoms have attracted significant attention due to their unique physicochemical properties. The core of sub-nanometer-thick metallenes is the undercoordinated metal nanosheet (NSs). Metallenes possess excellent electrical conductivity and an extremely large specific surface area, along with abundant surface active sites, resulting in unparalleled catalytic activity. Furthermore, the high atomic utilization rate of metallenes helps reduce the amount of precious metals used in catalysts and lower catalyst costs. Therefore, metallenes have become indispensable catalytic materials for many energy conversion technologies, such as fuel cells, water electrolysis, and carbon dioxide reduction, and have broad application prospects in various energy conversion and storage fields.

[0004] Metal atoms tend to form a densely packed bulk structure, making two-dimensional metalene materials thermodynamically difficult to synthesize, thus posing a significant challenge to the preparation of metalenes. For example, it is very difficult to peel metalenes from the three-dimensional structure of metals using a top-down method. Even if peeling is successful, the strong surface energy will cause the monolayer metal atoms to recombine and aggregate. In order to suppress the aggregation between layers and promote the lateral growth of metal atoms along the plane, a bottom-up strategy is mainly used to prepare metalenes. The specific methods mainly include ligand-restricted growth, template-based anisotropic growth, and topological reduction of layered materials. (1) Ligand-restricted growth: mainly guides the metal to grow anisotropically by ligand constraint. For example, CO is used as a ligand confinement agent to suppress the growth of palladium (Pd) in the

[111] direction and thus synthesize Pd metal enes (Pd NSs); pyrolysis of Cr(CO)6 to produce CO is used as a ligand confinement agent to assist in the synthesis of Cr-doped Pd metal enes (Cr-Pdene); formaldehyde solvent that can decompose to produce CO is used to assist in the synthesis of rhodium metal enes (Rh NSs); halogen ions and amines, which have similar ligand confinement effects to CO, are used as ligands to confine the synthesis of antimony (Sb) metal enes (Sb NSs) and Co metal enes (CoNSs). (2) Template-mediated anisotropic growth method: mainly using two-dimensional materials as templates to make cores and guide the epitaxial or planar anisotropic growth of metal enes. For example, layered bimetallic hydroxides (LDH), graphene oxide (GO), and graphene were used as templates to provide controllable spatial effects, and ultrathin gold (Au) metalenes (Au NSs) and iron metalenes (Fe NSs) were synthesized in the interlayer of LDH, on the GO substrate, and in the pores of graphene, respectively. (3) Topological reduction method of layered materials: This method achieves the transformation of metal oxides / hydroxides with layered structures to the metallic state while retaining crystallinity and atomically thin two-dimensional morphology. For example, layered bimetallic Fe / Co-LDH was converted into iron-cobalt alloy metalenes (FeCo NSs), and layered BiOI was topologically completely converted into Bi metalenes. In order to further control the structure of two-dimensional metalenes to improve their intrinsic properties, high-performance metalene materials were prepared by defect engineering, phase engineering, strain engineering, interface engineering, doping and alloying strategies. For example, porous Pd metal olefins (Pd NSs) were prepared using defect engineering strategies; amorphous / crystalline heterophase PdCu metal nanoolefins (PdCu NSs) were prepared using phase engineering strategies; PdMo@Pd bimetallic olefins (PdMo@Pd NSs) were prepared using strain engineering strategies; RuOx atomically dispersed on Pd nanosheets (RuOx-PdNSs) were prepared using interface engineering strategies; and PdIr bimetallic olefins (PdIr NSs) were prepared using doping and alloying strategies.

[0005] Based on the above discussion, the metals primarily selected for preparing noble metal alkenes are Pd and Rh, which have strong interactions with CO ligands. Of these, only Pd can be used as an ORR catalyst for fuel cells. However, Pd catalysts only exhibit high ORR activity under alkaline conditions, while their ORR activity is low under acidic conditions. Furthermore, alkaline proton exchange membrane (PEM) technology is still immature, and the application of Pd catalysts in fuel cells remains a long way off. Currently, Pt catalysts, which exhibit high ORR activity under acidic conditions, are mainly used as ORR catalysts in proton exchange membrane fuel cells. However, due to the weak interaction between Pt and CO ligands, it is difficult to synthesize Pt metal alkenes using the aforementioned ligand-constrained methods. In addition, the metal alkenes reported in the literature have large lateral dimensions, mostly in the micrometer range, making it difficult to uniformly disperse them on nanoscale conductive porous carbon. Noble metal alkenes must be supported on porous carbon supports to be used in fuel cells. To date, achieving anisotropic growth of Pt atoms within the pores of a carbon support to prepare high-performance Pt NSs / C catalysts supported on porous carbon for use in fuel cells remains a significant challenge. Summary of the Invention

[0006] To address the shortcomings of related technologies, this invention provides a porous carbon-supported platinum metal nano-ene catalytic material, its preparation method, and its application. This solves the current problems of synthesizing Pt metal enes and the difficulty in loading the large lateral size of metal enes into porous carbon channels. The catalyst material has the advantages of excellent electrochemical active area and oxygen reduction catalytic activity, and exhibits good durability at both low and high potentials.

[0007] One objective of this invention is to provide a method for preparing porous carbon-supported platinum metal nano-olefin catalytic materials, specifically including the following steps: (1) The conductive porous carbon support is subjected to high-temperature annealing to obtain the porous carbon support after high-temperature annealing.

[0008] (2) The porous carbon support after high-temperature annealing is placed in a mixed solution of platinum salt precursor and transition metal salt precursor, and then ultrasonically treated to obtain the original slurry of the mixture.

[0009] (3) Evaporate the original slurry of the mixture under stirring, and then dry it to obtain a composite powder of metal precursor and porous carbon support; (4) The composite powder was subjected to carbothermal reduction treatment, followed by cooling, to obtain MO. x / Pt NSs / C mixture powder.

[0010] (5) To MO x The Pt NSs / C mixture powder was acid-washed, then filtered to obtain a solid material, which was then washed and dried to obtain a porous carbon-supported platinum metal nano-olefin catalyst material, denoted as Pt NSs / C.

[0011] Preferably, the conductive porous carbon support in step (1) is one of Ketjen Black EC-300J, Ketjen Black EC-600JD, acetylene black, and Cabot BP2000.

[0012] Preferably, the high-temperature annealing treatment in step (1) is carried out in a mixed atmosphere of argon (Ar) and hydrogen (H2), with argon and hydrogen forming a mixed atmosphere in a volume ratio of (2~10):1; the conditions for the high-temperature annealing treatment are: heat treatment at 700~1200℃ for 0.5~10h.

[0013] Preferably, the platinum salt precursor in step (2) is one of platinum acetylacetonate, dihydroxytetramineplatinum, or ethanolamine hydroxyplatinum containing an oxygen group; the transition metal salt precursor is one of cobalt acetylacetonate, copper acetylacetonate, iron acetylacetonate, or nickel acetylacetonate containing an oxygen group.

[0014] More preferably, the platinum salt precursor in step (2) is platinum acetylacetonate with an oxygen-containing group.

[0015] Preferably, in step (2), the mass ratio of platinum salt precursor to transition metal salt precursor in the mixed solution of platinum salt precursor and transition metal salt precursor is (0.5~10):1; the solvent of the mixed solution of platinum salt precursor and transition metal salt precursor is acetone; the platinum content in the original slurry of the mixture is 0.5~10 mg / mL; the porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of (0.5~3):1; the ultrasonic treatment power is 300~650W, and the ultrasonic time is 10~50min.

[0016] Preferably, the stirring speed in step (3) is 200~600 rpm; the evaporation is carried out by water bath evaporation or rotary evaporation, the evaporation temperature is 40~80℃, and the evaporation time is 0.5~2h.

[0017] Preferably, the conditions for the carbothermic reduction treatment in step (4) are: to keep warm at a temperature of 150~450℃ for 4~12h under an inert atmosphere.

[0018] More preferably, the atmosphere for the carbothermic reduction treatment in step (4) is an argon atmosphere, and the flow rate is 90 mL / min.

[0019] Preferably, the pickling temperature in step (5) is 50~90℃, the pickling time is 9~22h, and the acid solution for pickling is one of sulfuric acid aqueous solution, acetic acid aqueous solution, perchloric acid aqueous solution or nitric acid aqueous solution, and the concentration of the acid solution is 2~13mol / L.

[0020] More preferably, the pickling in step (5) is carried out under stirring conditions.

[0021] The second objective of this invention is to provide a porous carbon-supported platinum metal nano-olefin catalytic material prepared by the method of this invention, wherein the material is a composite material formed by highly dispersed nanoscale platinum sheets loaded on a porous carbon support.

[0022] The third objective of this invention is to provide an application of the porous carbon-supported platinum metal nano-ene catalyst material prepared by this invention in hydrogen-oxygen fuel cells.

[0023] Mechanism of the invention: This invention utilizes interface engineering to regulate surface energy using carbon monoxide (CO) ligands, combined with a selective acid washing strategy, to prepare a high-performance porous carbon-supported Pt metal nanoene Pt NSs / C catalyst.

[0024] This invention achieves the directed synthesis of two-dimensional platinum nano-enes within carbon channels based on the significant difference in reduction potential between platinum and transition metals and the mechanism of ligand-induced anisotropic growth. First, high-temperature annealing eliminates oxygen-containing groups on the carbon support surface and enhances graphitization. Then, the treated carbon support is immersed in an acetone solution of oxygen-containing Pt salt precursors and oxygen-containing transition metal (M=Co, Fe, Ni) salt precursors. After evaporation, a complex of precursor molecules adsorbed within the carbon channels is obtained. Second, utilizing the significant reduction potential difference between Pt and transition metal M, carbothermic reduction is performed within the temperature range where Pt and M are mutually insoluble (150–450 °C). This allows Pt ions to be preferentially and rapidly reduced to Pt atoms and nucleate and grow within the carbon channels, while M ions can only be reduced to the corresponding transition metal oxides (MO). x Furthermore, the thermally reduced metal precursor containing oxygen groups releases a significant amount of carbon monoxide (CO), which is selectively adsorbed onto MO. x High-energy crystal planes (such as the {100} plane) are used to inhibit the growth of this crystal plane. MO is guided by CO ligand constraint. x Anisotropic growth forms two-dimensional sheet-like MO x Simultaneously, its two-dimensional sheet-like interface restricts the isotropic growth of Pt, forcing Pt to grow along a two-dimensional direction, forming Pt nanoolefins (Pt NSs). Finally, MO is selectively removed by acid washing. x Templates were used to obtain highly dispersed Pt nano-olefin catalysts (Pt NSs / C) materials confined in carbon pores. The resulting Pt NSs / C materials exhibited high electrochemical active area, excellent catalytic activity, and good durability in acidic oxygen reduction reactions due to the abundant exposed active sites and pore confinement effect.

[0025] The beneficial effects of this invention are: (1) This invention provides a novel method for preparing porous carbon-supported Pt metal nanoenes. The Pt metal nanoenes of this invention are confined within the pores of porous carbon, allowing the Pt nanoenes, which expose more Pt atoms than nanoparticles, to exhibit high catalytic activity during electrocatalytic reactions. The pore-confined Pt nanoenes inhibit the migration and aggregation of Pt nanoenes during electrochemical reactions, thereby alleviating catalytic deactivation and improving the durability of catalytic materials.

[0026] (2) In this invention, Pt metal nano-ene has a high specific surface area and abundant active sites, which can significantly improve the utilization efficiency of Pt atoms in Pt NSs / C catalyst and significantly reduce the amount of Pt in the catalyst.

[0027] (3) The method of the present invention is simple, environmentally friendly, and has low requirements for production equipment, low cost, easy to mass-produce, and has the prospect of industrialization. Attached Figure Description

[0028] Figure 1 The X-ray diffraction patterns are of the materials prepared in Example 1 and Comparative Example 1 of this invention.

[0029] Figure 2 This is a low-magnification transmission electron microscope (TEM) image of the porous carbon-supported platinum metal nano-ene catalytic material prepared in Example 1 of the present invention.

[0030] Figure 3 This is a high-magnification transmission electron microscope (TEM) image of the porous carbon-supported platinum metal nano-ene catalytic material prepared in Example 1 of the present invention; Figure 3 (a) is a TEM image with a 20 nm scale. Figure 3 (b) is a TEM image with a 5nm scale.

[0031] Figure 4 This is an atomic resolution aberration-corrected transmission electron microscope (AC-TEM) image of the porous carbon-supported platinum metal nano-olefin catalytic material prepared in Example 1 of the present invention. Figure 4 (a) is a bright-field high-magnification BF-HRTEM image. Figure 4 (b) is the high-angle dark field HAADF-STEM plot of the corresponding field of view.

[0032] Figure 5 The above are high-resolution X-ray photoelectron spectroscopy (XPS) spectra of the catalytic material Pt 4f prepared in Example 1 and Comparative Example 1 of this invention. Figure 5 (a) is the XPS wide scan image; Figure 5 (b) is the high-resolution XPS spectrum.

[0033] Figure 6Cyclic voltammetry (CV) plots and polarization (LSV) plots of the porous carbon-supported platinum metal nano-olefin catalytic material prepared in Example 1 of this invention and a commercial catalyst in a N2-saturated 0.1 M HClO4 solution. Figure 6 (a) shows the cyclic voltammetry (CV) plots of the porous carbon-supported platinum metal nano-olefin catalytic material prepared in Example 1 and the commercial catalyst in a N2-saturated 0.1 M HClO4 solution. Figure 6 (b) shows the polarization (LSV) diagrams of the porous carbon-supported platinum metal nano-ene catalyst prepared in Example 1 and the commercial catalyst in an O2-saturated 0.1M HClO4 solution.

[0034] Figure 7 Cyclic voltammetry (CV) plots and polarization (LSV) plots of the porous carbon-supported platinum metal nano-olefin catalytic material prepared in Example 2 of the present invention and the catalyst in Comparative Example 2 are shown. Figure 7 (a) shows the cyclic voltammetry (CV) plots of the porous carbon-supported platinum metal nano-olefin catalyst prepared in Example 2 and the catalyst in Comparative Example 2 in a N2-saturated 0.1 M HClO4 solution. Figure 7 (b) shows the polarization (LSV) diagrams of the porous carbon-supported platinum metal nano-ene catalyst prepared in Example 2 and the catalyst in Comparative Example 2 in an O2-saturated 0.1 M HClO4 solution.

[0035] Figure 8 The polarization (LSV) diagram of the porous carbon-supported platinum metal nano-ene catalytic material prepared in Example 3 of the present invention in an O2-saturated 0.1 M HClO4 solution.

[0036] Figure 9 Cyclic voltammetry (CV) plots and polarization (LSV) plots of the porous carbon-supported platinum metal nano-olefin catalytic material prepared in Example 4 of the present invention and the catalyst of Comparative Example 1 in N2-saturated 0.1 M HClO4 solution. Figure 9 (a) shows the cyclic voltammetry (CV) plots of the porous carbon-supported platinum metal nano-olefin catalyst prepared in Example 4 and the catalyst in Comparative Example 1 in a N2-saturated 0.1 M HClO4 solution. Figure 9 (b) shows the polarization (LSV) diagrams of the porous carbon-supported platinum metal nano-ene catalyst prepared in Example 4 and the catalyst in Comparative Example 1 in an O2-saturated 0.1 M HClO4 solution.

[0037] Figure 10The polarization (LSV) diagram of the porous carbon-supported platinum metal nano-ene catalytic material prepared in Example 5 of the present invention in an O2-saturated 0.1M HClO4 solution.

[0038] Figure 11 This is a comparative bar chart showing the electrochemical active area of ​​the materials prepared in Examples 1-3 and Comparative Examples 1-3 in a N2-saturated 0.1 M HClO4 solution, as measured by cyclic voltammetry (CV).

[0039] Figure 12 This is a comparative bar chart showing the oxygen reduction (ORR) mass activity of the materials prepared in Examples 1-3 and Comparative Examples 1-3 in O2-saturated 0.1 M HClO4 solution as measured by linear sweep voltammetry (LSV).

[0040] Figure 13 This is a bar chart comparing the electrochemical active area (ECSA) of the materials prepared in Example 1 and Comparative Example 1 of the present invention after 10,000, 20,000, and 30,000 CV cycles at a low potential of 0.6~0.95V in a N2-saturated 0.1 M HClO4 solution with the initial value.

[0041] Figure 14 This is a bar chart comparing the mass activity (MA) of the materials prepared in Example 1 and Comparative Example 1 of the present invention after 10,000, 20,000 and 30,000 CV cycles at a high potential of 0.6~0.95V in a N2-saturated 0.1 M HClO4 solution with the initial values. Detailed Implementation

[0042] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. In the embodiments and comparative examples of this invention, unless otherwise specified, all chemical reagents were commercially available analytical grade. The platinum acetylacetonate precursor used in the embodiments and comparative examples of this invention is platinum acetylacetonate containing an oxygen-containing group.

[0043] Example 1 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon support Ketjen Black EC-300J was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0044] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetonate and cobalt acetylacetonate (the mass ratio of platinum acetylacetonate to cobalt acetylacetonate in the solution is 2:1), and then ultrasonically treated with a power of 400W for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 2mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 3:4 of the porous carbon support after high-temperature annealing to cobalt acetylacetonate.

[0045] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0046] (4) The composite powder was placed in a quartz tube and heated from 20°C to 250°C under an argon atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 250°C for 8 h, followed by cooling to room temperature to obtain CoO. x / Pt NSs / C mixture powder.

[0047] (5) CoO x The Pt NSs / C mixture powder was placed in an 8.75 mol / L aqueous acetic acid solution and acid-washed for 16 h at a constant temperature of 80 °C and magnetic stirring at 500 rpm. The solid material was then filtered and washed with ultrapure water. Finally, it was placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-olefin catalyst material, denoted as Pt NSs / C.

[0048] To confirm the successful fabrication of porous carbon-supported platinum metal nanoparticle catalytic material (Pt NSs / C) in this embodiment, Pt NSs / C was characterized in detail using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and atomic resolution aberration-corrected electron microscopy (AC-TEM). The XRD patterns (…) Figure 1It can be seen that diffraction peaks appear at 2θ = 39.6°, 46.0°, 67.3° and 81.1°, corresponding to the (111), (200), (220) and (311) crystal plane diffraction of Pt metal, respectively. This is a match between the face-centered cubic (fcc) crystal form of Pt and the standard card PDF#87-0646. There are no diffraction peaks of Co metal and cobalt oxide, indicating that there are no cobalt compounds in the Pt NSs / C catalytic material. XPS test results show that there are no XPS peaks of Co, proving that there is no Co element on the surface of the prepared catalytic material. The binding energy of Pt 4f can be obtained from the high-resolution XPS spectrum as 71.5 eV, indicating that the chemical state of Pt corresponds to the zero-valent Pt(0) form, rather than an ionic or other compound state. Low-magnification TEM ( Figure 2 Characterization results showed that Pt nanoparticles were uniformly dispersed on the porous carbon support; counting 300 nanoparticles, the average particle size of the Pt NSs / C prepared in Example 1 was found to be 3.1 ± 0.6 nm, and the Pt nanoparticles were uniformly dispersed on the porous carbon support (see...). Figure 3 Furthermore, characterization with atomic-resolution spherical aberration electron microscopy revealed bright-field high-magnification TEM images of Pt NSs / C (see...). Figure 4 In (a)), the Pt nanoparticles on the carbon support do not exhibit a typical spherical shape. Instead, they appear as nanosheets or short stripes with less pronounced black-and-white contrast on the graphite layer of the carbon support, and lattice fringes are visible on some of these nanosheets or short stripes. However, the high-angle dark-field STEM image of Pt NSs / C shows nanosheets or short stripes with distinct brightness and darkness, and clear lattice fringes (see [link to image]). Figure 4 (b) Bright-field high-magnification TEM images mainly reflect the black-and-white contrast after the electron beam is absorbed by the sample following electron beam irradiation. Figure 4 (a) The weak contrast between the sheet-like or short strip-shaped Pt nanoparticles and the carbon support indicates that the Pt nanosheets or short strips are relatively thin, resulting in a small difference in contrast between them. Since dark-field STEM primarily reflects differences in atomic numbers within the sample, the atomic number of Pt (78) is much greater than that of carbon (6), leading to a significant difference in brightness between the nanosheets / strips and the carbon. Based on XRD and TEM characterization, combined with bright-field high-magnification TEM and high-angle dark-field STEM analysis, it is fully confirmed that the Pt nanoparticles distributed on the carbon support are sheet-like Pt metal nanoenes. Therefore, this embodiment confirms the preparation of a carbon-supported Pt nanoene catalytic material.

[0049] Depend on Figure 5 As shown in the XPS broad scan image of (a), the catalytic material prepared in Example 1 has no Co XPS peaks, only Pt XPS peaks, indicating that the prepared catalytic material does not contain Co on its surface; Figure 5 (b) The high-resolution XPS spectrum shows that Pt 4f 7 / 2 The binding energy is 71.4 eV. Pt exists in the form of zero-valent metal (Pt(0)) rather than in the form of ions or other compounds, which proves that carbothermic reduction has reduced Pt ions to metallic Pt.

[0050] Cyclic voltammetry results based on the hydrogen underpotential deposition (HUPD) method, see [link to relevant documentation]. Figure 6 In example (a), the electrochemically active surface area (ECSA) of the catalyst prepared in Example 1 is as high as 191 m². 2 g -1 ECSA (60m) of a comparative commercial Pt / C catalyst 2 g -1 The efficiency of ECSA is increased by 3.2 times. According to electrochemical theory, the quantification of ECSA strictly follows the adsorption stoichiometry relationship of one accessible active site on the Pt surface corresponding to one hydrogen atom. Its value directly reflects the total number of exposed Pt active sites and the Pt atom utilization rate on the catalyst surface. Therefore, the catalyst prepared in Example 1 has 3.2 times more accessible Pt active sites than the comparative example, indicating a significant improvement in Pt atom utilization. Combining the morphology of Pt nanomaterials with the structure-activity relationship of ECSA, it can be inferred that the nanoparticles in the catalyst of the examples have a two-dimensional sheet-like nanostructure. The Pt metal nano-ene in the catalyst of the examples is the core reason for its ultra-high Pt active site exposure. Figure 6 As can be seen in (b), compared with commercial Pt / C, the present invention significantly improves the catalytic activity of the catalyst by introducing cobalt oxide as an auxiliary agent into the catalytic system of the examples and by taking advantage of the strong interfacial interaction between cobalt oxide and metallic platinum, thereby regulating the electronic structure of platinum through electron transfer effect and optimizing the adsorption energy of oxygen reduction reaction intermediates.

[0051] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​140 m². 2 / g (see also) Figure 11 The mass activity is 239 mA / mg (see...). Figure 12 ).

[0052] Compared to the comparative catalyst prepared by conventional methods, the catalyst in this embodiment showed a decrease in electrochemical active area (ECSA) of only 9.74% after 30,000 accelerated aging cycles (see [reference]). Figure 13 The decay rate of mass activity (MA) was only 9.54% (see [reference]). Figure 14 This demonstrates that the preparation method in this embodiment significantly improves the durability and stability of the catalyst.

[0053] Example 2 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon support acetylene black was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0054] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetone and iron acetylacetone (the mass ratio of platinum acetylacetone to iron acetylacetone in the solution is 1:2), and then ultrasonically treated with a power of 400W for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 2mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 4:3 of the porous carbon support after high-temperature annealing to iron acetylacetone.

[0055] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0056] (4) The composite powder was placed in a quartz tube and heated from 20°C to 250°C in an Ar atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 250°C and held for 8 h. The mixture was then cooled to room temperature to obtain FeO. x / Pt NSs / C mixture powder.

[0057] (5) FeO x The Pt NSs / C mixture powder was placed in an 8.75 mol / L aqueous acetic acid solution and acid-washed for 16 h at a constant temperature of 80 °C and magnetic stirring at 500 rpm. The solid material was then filtered to obtain a solid material, washed with ultrapure water, and then placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-ene catalyst.

[0058] XRD, XPS, TEM, and AC-TEM tests on the catalytic material prepared in this embodiment revealed that it contained no iron compounds. XPS analysis showed no Co peaks, indicating the absence of Co on the surface of the catalytic material. The Pt nanoparticles were found to exist in the zero-valent Pt(0) form, rather than as ions or other compounds, and were uniformly dispersed on the porous carbon support. The Pt nanoparticles distributed on the carbon support were thin-film Pt metal nano-enes. Comprehensive analysis concluded that this embodiment successfully prepared a carbon-supported Pt nano-ene catalytic material.

[0059] The cyclic voltammetry (CV) diagram of the catalyst material in the N2-saturated 0.1 M HClO4 solution and the polarization (LSV) diagram in the O2-saturated 0.1 M HClO4 solution of this embodiment are shown below. Figure 7 As shown, Figure 7 This indicates that introducing iron oxide as an auxiliary agent into the catalyst system of this embodiment can significantly improve the electrochemical active area and catalytic activity of the catalyst.

[0060] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​133 m². 2 / g (see also) Figure 11 The mass activity is 192 mA / mg (see...). Figure 12 ).

[0061] After 30,000 accelerated aging cycles, the catalyst in this embodiment showed a 5% degradation rate for ECSA and an 11% degradation rate for MA. This indicates that the preparation method in this embodiment significantly improves the durability and stability of the catalyst.

[0062] Example 3 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon support Ketjen Black EC-600JD was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0063] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetonate and copper acetylacetonate (the mass ratio of platinum acetylacetonate to copper acetylacetonate in the solution is 3:3), and then ultrasonically treated at a stirring speed of 500 rpm and a power of 400 W for 20 min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 2 mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 1:1 between the porous carbon support after high-temperature annealing and copper acetylacetonate.

[0064] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0065] (4) The composite powder was placed in a quartz tube and heated from 20°C to 280°C in an Ar atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 280°C and held for 8 h. The mixture was then cooled to room temperature to obtain CuO. x / Pt NSs / C mixture powder.

[0066] (5) CuO x The Pt NSs / C mixture powder was placed in an 8.75 mol / L aqueous acetic acid solution and acid-washed for 16 h at a constant temperature of 80 °C and magnetic stirring at 500 rpm. The solid material was then filtered to obtain a solid material, washed with ultrapure water, and then placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-ene catalyst.

[0067] XRD, XPS, TEM, and AC-TEM tests on the catalytic material prepared in this embodiment revealed that it contained no copper compounds. XPS analysis showed no Co peaks, indicating the absence of Co on the surface of the catalytic material. The Pt nanoparticles were found to exist in the zero-valent Pt(0) form, rather than as ions or other compounds, and were uniformly dispersed on a porous carbon support. The Pt nanoparticles distributed on the carbon support were thin-film Pt metal nano-enes. Comprehensive analysis concluded that this embodiment successfully prepared a carbon-supported Pt nano-ene catalytic material.

[0068] The cyclic voltammetry (CV) diagram of the catalyst material in the N2-saturated 0.1 M HClO4 solution and the polarization (LSV) diagram in the O2-saturated 0.1 M HClO4 solution of this embodiment are shown below. Figure 8 As shown, Figure 8 This indicates that introducing copper oxide as an auxiliary agent into the catalyst system of this embodiment can significantly improve the catalytic activity of the platinum-carbon catalyst.

[0069] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​80 m². 2 / g (see also) Figure 11 The mass activity is 222 mA / mg (see...). Figure 12 ).

[0070] After 30,000 accelerated aging cycles, the catalyst in this embodiment exhibited an 11% degradation rate for ECSA and an 18% degradation rate for MA. This demonstrates that the preparation method in this embodiment significantly improves the durability and stability of the catalyst.

[0071] Example 4 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon carrier Cabot BP2000 was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon carrier after high-temperature annealing.

[0072] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetonate and nickel acetylacetonate (the mass ratio of platinum acetylacetonate to nickel acetylacetonate in the solution is 3:5), and then ultrasonically treated with a power of 400W for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 2mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 4:3 of the porous carbon support after high-temperature annealing to nickel acetylacetonate.

[0073] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0074] (4) The composite powder was placed in a quartz tube and heated from 20°C to 220°C in an Ar atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 220°C and held for 8 h. The mixture was then cooled to room temperature to obtain NiO. x / Pt NSs / C mixture powder.

[0075] (5) NiO x The Pt NSs / C mixture powder was placed in an 8.75 mol / L aqueous acetic acid solution and acid-washed for 16 h at a constant temperature of 80 °C and magnetic stirring at 500 rpm. The solid material was then filtered to obtain a solid material, washed with ultrapure water, and then placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-ene catalyst.

[0076] XRD, XPS, TEM, and AC-TEM tests on the catalytic material prepared in this embodiment revealed that it contained no nickel compounds. XPS analysis showed no Co peaks, indicating the absence of Co on the surface of the catalytic material. The Pt nanoparticles were found to exist in the zero-valent Pt(0) form, rather than as ions or other compounds, and were uniformly dispersed on the porous carbon support. The Pt nanoparticles distributed on the carbon support were sheet-like Pt metal nano-enes. Comprehensive analysis concluded that this embodiment successfully prepared a carbon-supported Pt nano-ene catalytic material.

[0077] The cyclic voltammetry (CV) diagram of the catalyst material in the N2-saturated 0.1 M HClO4 solution and the polarization (LSV) diagram in the O2-saturated 0.1 M HClO4 solution of this embodiment are shown below. Figure 9 As shown, Figure 9 This indicates that introducing nickel oxide as an auxiliary agent into the catalyst system of the examples can significantly improve the electrochemical area and catalytic activity of the catalyst.

[0078] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​191 m². 2 / g, with a mass activity of 375mA / mg.

[0079] In this embodiment, after 30,000 accelerated aging cycles, the ECSA catalyst exhibited a degradation rate of 12%, and the MA catalyst exhibited a degradation rate of 10%. This demonstrates that the preparation method of this embodiment significantly improves the durability and stability of the catalyst.

[0080] Example 5 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon support Ketjen Black EC-300J was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0081] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetonate and manganese acetylacetonate (the mass ratio of platinum acetylacetonate to manganese acetylacetonate in the solution is 3:5), and then ultrasonically treated with a power of 400W for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 2mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 4:3 of the porous carbon support after high-temperature annealing to manganese acetylacetonate.

[0082] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0083] (4) The composite powder was placed in a quartz tube and heated from 20°C to 220°C in an Ar atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 220°C and held for 8 h. The mixture was then cooled to room temperature to obtain MnO. x / Pt NSs / C mixture powder.

[0084] (5) MnO x The Pt / NSs / C mixture powder was placed in a 10 mol / L aqueous acetic acid solution and acid-washed for 16 h at a constant temperature of 80 °C and magnetic stirring at 500 rpm. The solid material was then filtered and washed with ultrapure water. Finally, it was placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-olefin catalyst.

[0085] XRD, XPS, TEM, and AC-TEM tests on the catalytic material prepared in this embodiment revealed that it contained no manganese compounds. XPS analysis showed no Co peaks, indicating the absence of Co on the surface of the catalytic material. The Pt nanoparticles were found to exist in the zero-valent Pt(0) form, rather than as ions or other compounds, and were uniformly dispersed on the porous carbon support. The Pt nanoparticles distributed on the carbon support were thin-film Pt metal nano-enes. Comprehensive analysis concluded that this embodiment successfully prepared a carbon-supported Pt nano-ene catalytic material.

[0086] Figure 10 This indicates that the introduction of manganese oxide as an auxiliary agent into the catalyst system of this embodiment can significantly improve the catalytic activity of the platinum-carbon catalyst.

[0087] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​66 m². 2 / g, with a mass activity of 199mA / mg.

[0088] In this embodiment, after 30,000 accelerated aging cycles, the ECSA catalyst exhibited a 5% degradation rate, while the MA catalyst showed a 15% degradation rate. This demonstrates that the preparation method of this embodiment significantly improves the durability and stability of the catalyst.

[0089] Example 6 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon support Ketjen Black EC-300J was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 2:1). The high-temperature annealing temperature was 1200℃ and the treatment time was 0.5h, thus obtaining the porous carbon support after high-temperature annealing.

[0090] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetone and manganese acetylacetone (the mass ratio of platinum acetylacetone to manganese acetylacetone in the solution is 10:1), and then ultrasonically treated with a power of 300W for 50min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 10mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 0.5:1 between the porous carbon support after high-temperature annealing and manganese acetylacetone.

[0091] (3) The original slurry of the mixture was placed in a rotary evaporator and stirred for 2 hours at a constant temperature of 40°C and 200 rpm. After the acetone was evaporated, the product was placed in a vacuum drying oven and dried under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0092] (4) The composite powder was placed in a quartz tube and heated from 20°C to 450°C in an Ar atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 450°C and held for 4 h. The mixture was then cooled to room temperature to obtain MnO. x / Pt NSs / C mixture powder.

[0093] (5) MnO x The Pt / NSs / C mixture powder was placed in a 13 mol / L sulfuric acid aqueous solution and acid-washed for 9 h at a constant temperature of 50 °C and magnetic stirring at 500 rpm. The solid material was then filtered and washed with ultrapure water. Finally, it was placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-olefin catalyst.

[0094] XRD, XPS, TEM, and AC-TEM tests on the catalytic material prepared in this embodiment revealed that it contained no cobalt compounds. XPS analysis showed no Co peaks, indicating the absence of Co on the surface of the catalytic material. The Pt nanoparticles were found to exist in the zero-valent Pt(0) form, rather than as ions or other compounds, and were uniformly dispersed on a porous carbon support. The Pt nanoparticles distributed on the carbon support were thin-film Pt metal nano-enes. Comprehensive analysis concluded that this embodiment successfully prepared a carbon-supported Pt nano-ene catalytic material.

[0095] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​95m². 2 / g, with a mass activity of 247mA / mg.

[0096] After 30,000 accelerated aging cycles, the catalyst in this embodiment exhibited a 7% degradation rate for ECSA and a 13% degradation rate for MA. This demonstrates that the preparation method in this embodiment significantly improves the durability and stability of the catalyst.

[0097] Example 7 A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material specifically includes the following steps: (1) The conductive porous carbon support Ketjen Black EC-300J was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 10:1). The high-temperature annealing temperature was 700℃ and the treatment time was 10h to obtain the porous carbon support after high-temperature annealing.

[0098] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetonate and manganese acetylacetonate (the mass ratio of platinum acetylacetonate to manganese acetylacetonate in the solution is 8:1), and then ultrasonically treated with a power of 650W for 10min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 0.5mg / mL. The porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of 3:1 between the porous carbon support after high-temperature annealing and manganese acetylacetonate.

[0099] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 30 minutes at a constant temperature of 80°C and 200 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0100] (4) The composite powder was placed in a quartz tube and heated from 20°C to 150°C in an Ar atmosphere at a flow rate of 90 mL / min. Carbothermic reduction treatment was then performed at 150°C and held for 12 h. The mixture was then cooled to room temperature to obtain MnO. x / Pt NSs / C mixture powder.

[0101] (5) MnO x The Pt NSs / C mixture powder was placed in a 2 mol / L nitric acid aqueous solution and acid-washed for 22 h at a constant temperature of 90 °C and magnetic stirring at 500 rpm. The solid material was then filtered to obtain a solid material, washed with ultrapure water, and then placed in a vacuum drying oven at 60 °C to obtain a porous carbon-supported platinum metal nano-olefin catalyst.

[0102] XRD, XPS, TEM, and AC-TEM tests on the catalytic material prepared in this embodiment revealed that it contained no cobalt compounds. XPS analysis showed no Co peaks, indicating the absence of Co on the surface of the catalytic material. The Pt nanoparticles were found to exist in the zero-valent Pt(0) form, rather than as ions or other compounds, and were uniformly dispersed on a porous carbon support. The Pt nanoparticles distributed on the carbon support were thin-film Pt metal nano-enes. Comprehensive analysis concluded that this embodiment successfully prepared a carbon-supported Pt nano-ene catalytic material.

[0103] The porous carbon-supported platinum metal nanoparticle catalytic material prepared in this embodiment has an electrochemical area of ​​87m². 2 / g, with a mass activity of 261mA / mg.

[0104] In this embodiment, after 30,000 accelerated aging cycles, the ECSA catalyst exhibited an 8% degradation rate, while the MA catalyst showed a 15% degradation rate. This demonstrates that the preparation method of this embodiment significantly improves the durability and stability of the catalyst.

[0105] This invention introduces an oxide auxiliary into the catalytic system. By leveraging the strong interfacial interaction between the oxide and metallic platinum, the electronic structure of platinum is controlled through electron transfer effect, and the adsorption energy of oxygen reduction reaction intermediates is optimized, thereby significantly increasing the electrochemical active area of ​​the catalyst.

[0106] Comparative Example 1 A method for preparing a Pt / C catalyst material specifically includes the following steps: (1) The conductive porous carbon support Ketjen Black EC-300J was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0107] (2) The porous carbon support after high-temperature annealing was placed in an acetone solution of platinum acetylacetone and then ultrasonically treated with 400W power for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture was 2mg / mL and the amount of porous carbon support after high-temperature annealing in the original slurry of the mixture was 49mg / mL.

[0108] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0109] (4) The composite powder was placed in a quartz tube and heated from 20°C to 250°C in an Ar atmosphere at a flow rate of 90 mL / min. The powder was then subjected to carbothermal reduction at 250°C for 8 hours and cooled to room temperature to obtain the Pt / C catalyst.

[0110] The X-ray diffraction pattern of the catalyst prepared in this comparative example is shown below. Figure 1 As shown. The XPS plot of the catalyst prepared in this comparative example is shown below. Figure 5 As shown.

[0111] The Pt / C catalyst material prepared in this comparative example has an electrochemical area of ​​52 m². 2 / g (see also) Figure 11 The mass activity is 162 mA / mg (see...). Figure 12 ).

[0112] After 30,000 cycles of accelerated aging testing, the ECSA in this comparative example showed a degradation rate of 51.32% (see [link to relevant documentation]). Figure 13 The attenuation rate of MA was 69.46%.

[0113] In the catalyst preparation process, this comparative catalyst lacks the strong interfacial interaction of oxides. Pt atoms grow isotropically to form spherical Pt nanoparticles, resulting in a small electrochemically active surface area of ​​only 52 μm. 2 The utilization rate of Pt atoms is low. Therefore, under the same Pt ​​loading, the number of Pt atoms participating in the catalytic reaction in the catalyst is small, ultimately resulting in low mass activity of the comparative catalyst, only 162 mA / mg. In addition, the weak interaction between spherical nanoparticles and carbon means that in the comparative catalyst, during multiple cyclic aging experiments at high and low potentials, the lack of strong anchoring between Pt nanoparticles and carbon support makes it prone to nano-migration and aggregation, oxidative dissolution and Ostwald ripening, as well as electrochemical corrosion of the carbon support. This leads to a significant decrease in the electrochemical active area and catalytic mass activity of the catalyst, resulting in poor catalyst durability.

[0114] Comparative Example 2 A method for preparing a Pt / C catalyst material specifically includes the following steps: (1) The conductive porous carbon support EC600JD was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0115] (2) The porous carbon support after high-temperature annealing was placed in an acetone solution of platinum acetylacetone and then ultrasonically treated with 400W power for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture was 2mg / mL and the amount of porous carbon support after high-temperature annealing in the original slurry of the mixture was 49mg / mL.

[0116] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0117] (4) The composite powder was placed in a quartz tube and heated from 20°C to 250°C in an Ar atmosphere at a flow rate of 90 mL / min. The powder was then subjected to carbothermal reduction at 250°C for 8 hours. The sample was then cooled to room temperature to obtain the Pt / C catalyst.

[0118] The cyclic voltammetry (CV) plot of this comparative catalyst in N2-saturated 0.1 M HClO4 solution and the polarization (LSV) plot in O2-saturated 0.1 M HClO4 solution are shown below. Figure 7 As shown, Figure 7 This indicates that without the introduction of iron oxide as an auxiliary agent, the electrochemical active area and catalytic activity of the catalyst are poor.

[0119] The Pt / C catalyst material prepared in this comparative example has an electrochemical area of ​​57 m². 2 / g (see also) Figure 11 The mass activity is 145 mA / mg (see...). Figure 12 ).

[0120] After 30,000 accelerated aging cycles, the comparative catalyst showed a 45% degradation rate for ECSA and a 50% degradation rate for MA. During catalyst preparation, this comparative catalyst lacked strong interfacial interactions from oxides; Pt atoms grew isotropically to form spherical Pt nanoparticles, resulting in a relatively small electrochemical active surface area of ​​only 57 μm. 2 The utilization rate of Pt atoms is low. Therefore, under the same Pt ​​loading, the number of Pt atoms participating in the catalytic reaction in the catalyst is small, ultimately resulting in low mass activity of the comparative catalyst, only 145 mA / mg. In addition, the weak interaction between spherical nanoparticles and carbon means that in the comparative catalyst, during multiple cyclic aging experiments at high and low potentials, the lack of strong anchoring between Pt nanoparticles and carbon support makes it prone to nano-migration and aggregation, oxidative dissolution and Ostwald ripening, as well as electrochemical corrosion of the carbon support. This leads to a significant decrease in the electrochemical active area and catalytic mass activity of the catalyst, resulting in poor catalyst durability.

[0121] Comparative Example 3 A method for preparing a Pt / C catalyst material specifically includes the following steps: (1) The conductive porous carbon support EC-300J was placed in a tube furnace and subjected to high-temperature annealing in a mixed atmosphere of Ar and H2 (the mixed atmosphere was composed of Ar and H2 in a volume ratio of 4:1). The high-temperature annealing temperature was 900℃ and the treatment time was 1.5h to obtain the porous carbon support after high-temperature annealing.

[0122] (2) The porous carbon support after high-temperature annealing is placed in an acetone solution of platinum acetylacetone and then ultrasonically treated with 400W power for 20min to obtain the original slurry of the mixture. The platinum content in the original slurry of the mixture is 2mg / mL and the amount of porous carbon support after high-temperature annealing added to the original slurry of the mixture is 30mg / mL.

[0123] (3) Place the original slurry of the mixture in a water bath and stir magnetically for 40 minutes at a constant temperature of 60°C and 500 rpm. After the acetone evaporates, place the product in a vacuum drying oven and dry it under vacuum at 60°C to obtain a composite powder of metal precursor and porous carbon support.

[0124] (4) The composite powder was placed in a quartz tube and heated from 20°C to 280°C in an Ar atmosphere with a flow rate of 90 mL / min. The carbothermic reduction treatment was carried out at 280°C and kept at the temperature for 8 hours. The sample collected after the sample was cooled to room temperature was a Pt / C catalyst.

[0125] The Pt / C catalyst material prepared in this comparative example has an electrochemical area of ​​65 nm. 2 / g (see also) Figure 11 The mass activity is 155 mA / mg.

[0126] After 30,000 cycles of accelerated aging test, the degradation rate of ECSA was 4% and that of MA was 10%.

[0127] In the catalyst preparation process, this comparative catalyst lacks the strong interfacial interaction of oxides. Pt atoms grow isotropically to form spherical Pt nanoparticles, resulting in a small electrochemically active surface area of ​​only 65 μm. 2The utilization rate of Pt atoms is low. Therefore, under the same Pt ​​loading, the number of Pt atoms participating in the catalytic reaction in the catalyst is small, ultimately resulting in low mass activity of the comparative catalyst, only 155 mA / mg. In addition, the weak interaction between spherical nanoparticles and carbon means that in the comparative catalyst, during multiple cyclic aging experiments at high and low potentials, the lack of strong anchoring between Pt nanoparticles and carbon support makes it prone to nano-migration and aggregation, oxidative dissolution and Ostwald ripening, as well as electrochemical corrosion of the carbon support, leading to a significant decrease in the electrochemical active area and catalytic mass activity of the catalyst.

[0128] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a porous carbon-supported platinum metal nano-olefin catalytic material, characterized in that, Specifically, the following steps are included: (1) The conductive porous carbon support is subjected to high-temperature annealing to obtain a porous carbon support after high-temperature annealing. (2) The porous carbon support after high-temperature annealing is placed in a mixed solution of platinum salt precursor and transition metal salt precursor, and then ultrasonically treated to obtain the original slurry of the mixture. (3) Evaporate the original slurry of the mixture under stirring, and then dry it to obtain a composite powder of metal precursor and porous carbon support; (4) The composite powder was subjected to carbothermal reduction treatment, followed by cooling, to obtain MO. x / Pt NSs / C mixture powder; (5) To MO x The Pt NSs / C mixture powder was acid-washed, then filtered to obtain a solid material, which was then washed and dried to obtain a porous carbon-supported platinum metal nano-olefin catalyst material, denoted as Pt NSs / C.

2. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, The conductive porous carbon support in step (1) is one of Ketjen Black EC-300J, Ketjen Black EC-600JD, acetylene black, or Cabot BP2000.

3. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, The high-temperature annealing treatment in step (1) is carried out in a mixed atmosphere of argon and hydrogen, with argon and hydrogen forming a mixed atmosphere in a volume ratio of (2~10):1; the conditions for the high-temperature annealing treatment are: heat treatment at 700~1200℃ for 0.5~10h.

4. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, The platinum salt precursor in step (2) is one of platinum acetylacetonate, dihydroxytetramineplatinum, or ethanolamine hydroxyplatinum containing an oxygen group; the transition metal salt precursor is one of cobalt acetylacetonate, copper acetylacetonate, iron acetylacetonate, or nickel acetylacetonate containing an oxygen group.

5. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, In step (2), the mass ratio of platinum salt precursor to transition metal salt precursor in the mixed solution of platinum salt precursor and transition metal salt precursor is (0.5~10):1; the solvent of the mixed solution of platinum salt precursor and transition metal salt precursor is acetone; the platinum content in the original slurry of the mixture is 0.5~10 mg / mL; the porous carbon support after high-temperature annealing is added to the original slurry of the mixture at a mass ratio of (0.5~3):1; the ultrasonic treatment power is 300~650W, and the ultrasonic time is 10~50min.

6. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, The stirring speed in step (3) is 200~600 rpm; the evaporation is carried out by water bath evaporation or rotary evaporation, the evaporation temperature is 40~80℃, and the evaporation time is 0.5~2h.

7. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, The conditions for the carbothermic reduction treatment in step (4) are: to keep warm at a temperature range of 150~450℃ for 4~12h under an inert atmosphere.

8. The method for preparing the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 1, characterized in that, The pickling temperature in step (5) is 50~90℃, the pickling time is 9~22h, and the acid solution for pickling is one of sulfuric acid aqueous solution, acetic acid aqueous solution, perchloric acid aqueous solution or nitric acid aqueous solution, and the concentration of the acid solution is 2~13mol / L.

9. The porous carbon-supported platinum metal nano-olefin catalytic material prepared by the method according to any one of claims 1 to 8, characterized in that, The material is a composite material formed by highly dispersed nanoscale platinum sheets loaded on a porous carbon support.

10. The application of the porous carbon-supported platinum metal nano-olefin catalytic material according to claim 9 in hydrogen-oxygen fuel cells.

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