Method for manufacturing platinum-based alloy catalyst through dry process and platinum-based alloy catalyst manufactured thereby

Abstract

The present invention relates to a method for manufacturing a platinum-based alloy catalyst through a dry process and a platinum-based alloy catalyst manufactured thereby and, specifically, to a method for manufacturing a platinum-based alloy catalyst and a platinum-based alloy catalyst manufactured thereby, the method comprising the steps of: mixing a platinum precursor, a transition metal precursor, and a support material to prepare a mixture (step 1); and heat-treating the mixture under an inert atmosphere to prepare a platinum-based alloy catalyst having a carbon shell (step 2). According to the present invention, the platinum-based alloy catalyst of the present invention can optimize the thickness of the carbon shell by using a transition metal having high solubility in carbon, can be stably distributed to prevent aggregation, and can further form a pore structure, thereby enhancing mass transfer properties and catalyst durability while exhibiting excellent electrochemical activity in an oxygen reduction reaction (ORR). In addition, by using the method of the present invention through a dry process, a platinum-based alloy catalyst can be manufactured in a simple, eco-friendly, and highly productive manner.

Description

Method for manufacturing a platinum-based alloy catalyst through a dry process and a platinum-based alloy catalyst produced thereby

[0001] The present invention relates to a platinum-based alloy catalyst used in fuel cells, oxygen reduction reactions (ORR), and other catalytic applications, and a method for manufacturing the same.

[0002] Proton exchange membrane fuel cells (PEMFCs) efficiently generate electricity from hydrogen fuel. PEMFC vehicles, such as the NEXO or Mirai, are already on the market. Furthermore, these fuel cell vehicles can be used as mobile power supplies without pollutant emissions. Autonomous vehicles, which have high power demands, will make fuel cell vehicles more suitable than purely battery-powered vehicles.

[0003] However, PEMFCs still require large quantities of platinum catalysts to accelerate the slow oxygen reduction (ORR) reaction. While platinum catalysts are capable of performing electrochemical reactions quickly and efficiently, withstanding demanding acidic conditions, and possessing heat resistance, they have limitations in simultaneously satisfying catalytic durability and cost-effectiveness. In particular, because platinum is a rare and expensive precious metal, the high price and limited supply of Pt can become serious obstacles hindering market expansion as the PEMFC vehicle market grows. Therefore, there is an urgent need to develop catalysts with higher activity and durability while minimizing the use of platinum.

[0004] Although nanoparticles with various shapes and compositions have been synthesized using colloidal synthesis methods, complex synthesis processes, small milligram-scale synthesis volumes, and the removal of surface-capping organic materials used during synthesis often occur. An easy and scalable synthesis method is desirable for commercial applications.

[0005] Furthermore, conventionally, the manufacturing of catalysts for fuel cells required a wet process that involved mixing and dispersing platinum precursors and carbon supports in a specific solvent, followed by filtering and drying the resulting catalyst. However, these steps of mixing / dispersing in solvents, filtering, and drying pose challenges for mass production and are characterized by complex processes and high costs. Therefore, a new manufacturing process and technology are required to address these issues.

[0006] It has been widely reported that forming platinum-based alloys with various transition metals such as Mn, Fe, Co, Ni, Cu, and Zn enhances ORR activity. The platinum electronic structure of Pt-TM (Pt-transition metal) alloys is modified by the underlying transition metal, leading to a decrease in the binding energy of oxygen species and an increase in ORR activity.

[0007]

[0008] To enhance the activity of such platinum-based alloy catalysts, they must possess the following characteristics.

[0009] 1) Platinum-transition metal alloy

[0010] 2) Uniform catalyst particle size

[0011] 3) Adsorption onto a support with a high surface area.

[0012]

[0013] Accordingly, there is a continuing demand for research on methods to manufacture platinum-based alloy catalysts, particularly platinum-based alloy catalysts, to ensure uniform particle size and improve catalyst stability and electrochemical performance.

[0014]

[0015] The prior art related to this is as follows.

[0016] Korean Patent Publication No. 2023-0169747 (Date of publication: Dec. 18, 2023) relates to a method for manufacturing a platinum alloy catalyst using an oxide coating, comprising: a first step of preparing a dispersion by mixing a commercial platinum catalyst and a transition metal precursor; a second step of preparing a catalyst by inserting an ultrasonic tip into the dispersion prepared through the first step and performing an ultrasonic process; a third step of performing a first heat treatment process on the catalyst prepared through the second step; a fourth step of performing an acid treatment process on the catalyst that has undergone the first heat treatment process through the third step; and a fifth step of preparing a platinum alloy catalyst by performing a second heat treatment process on the catalyst that has undergone the acid treatment process through the fourth step.

[0017] Korean Registered Patent No. 10-2291160 (Registration Date: August 11, 2021) relates to a gold-doped platinum-based alloy catalyst for fuel cells and a method for manufacturing the same, wherein the catalyst comprises a conductive core comprising a platinum and cobalt alloy; and a surface layer doped with cobalt included on the surface of the conductive core, wherein the gold of the catalyst is dispersed in a monatomic form at a rate of 90% or more.

[0018] Korean Registered Patent No. 10-2254764 (Registration Date: May 14, 2021) relates to a fluorine-doped tin oxide support and a platinum catalyst for a fuel cell containing the same, comprising the steps of: adding a tin precursor at 5 to 17 wt% and a nanotube template material at 10 to 23 wt% based on the total weight of the solvent to a spinning solvent, and adding and mixing a fluorine precursor at 5 to 40 mol%; electrospinning a solution containing the tin precursor and the fluorine precursor at a rate of 0.3 to 0.7 ml / h while applying a voltage of 17 to 20 kV to produce fluorine-doped tin oxide nanofibers; and heat-treating the nanofibers at 500 to 700°C for 1 to 3 hours in an oxygen or air atmosphere to produce a fluorine-doped tin oxide support in the form of a nanotube support. The present invention relates to a method for manufacturing a platinum catalyst for a fuel cell, comprising the step of supporting a platinum-based alloy catalyst on a fluorine-doped tin oxide support, wherein the fluorine is doped at 5 to 10 at.% relative to the total number of atoms of the fluorine-doped tin oxide support prior to supporting the platinum-based alloy catalyst.

[0019] Korean Patent Registration No. 2724367 (Registration Date: Oct. 28, 2024) relates to a core-shell catalyst with improved durability and a method for manufacturing the same, comprising the steps of: irradiating a solution containing a reducing solvent, a precious metal precursor, a transition metal precursor, and a carbon support with ultrasound, thereby forming a cavity due to the irradiation of ultrasound and forming transition metal precursor core and precious metal precursor shell particles due to a vapor pressure difference; and nitriding the transition metal precursor core and precious metal precursor shell particles under a gaseous nitrogen source at a temperature of 450 to 550°C and a pressure of 60 to 100 bar, wherein the transition metal may be any one selected from the group consisting of Y, La, Ce, Zn, and Mn.

[0020] Korean Patent Publication No. 2023-0169749 (Publication Date: Dec. 18, 2023) relates to a method for controlling the shape of palladium for an electrode catalyst through concentration control, comprising: a first step of preparing a solution by dispersing a palladium precursor in a solvent; a second step of purging an inert gas into the solution prepared through the first step; a third step of inducing reduction of the palladium precursor in the solution by purging carbon monoxide (CO) gas into the solution obtained through the second step; a fourth step of adding and dispersing a carbon support into the solution obtained through the third step; and a fifth step of manufacturing a nanosheet by filtering and drying the dispersed solution obtained through the fourth step.

[0021] Korean Patent Publication No. 2023-0161557 (Publication Date: Nov. 28, 2023) relates to a palladium-transition metal core-based core-shell electrode catalyst and a method for manufacturing the same, comprising: a first step of preparing a slurry by irradiating a dispersion solution containing a solvent, a platinum precursor, a palladium precursor, a carbon support, and a transition metal precursor with ultrasound; a second step of preparing a solid by filtering the slurry prepared through the first step, followed by washing and drying; and a third step of preparing a core-shell electrode catalyst by heat-treating the solid prepared through the second step in a specific gas atmosphere.

[0022] Korean Patent Registration No. 2496278 (Registration Date: Feb. 10, 2023) relates to a method for controlling the size of core-shell nanoparticles, comprising the steps of: preparing a slurry by irradiating a dispersion containing a reducing solvent, a carbon support, a transition metal precursor, and a precious metal precursor with ultrasound; preparing a solid by filtering the prepared slurry, washing, and drying it; and preparing nanoparticles by heat-treating the dried solid under an N2 atmosphere at a pressure of 1 to 80 bar, a temperature of 450 to 600 ℃, and for 30 minutes to 10 hours, thereby controlling the size of core-shell nanoparticles to have excellent stability (durability), a small average diameter, and excellent dispersion and uniformity without performing a complex post-treatment process to remove the protective layer used in conventional heat treatment.

[0023] Korean Patent Publication No. 2023-0130846 (Publication Date: Dec. 19, 2024) relates to a method for manufacturing core-shell particles using a divalent platinum precursor and carbon monoxide, comprising: a first step of adding a palladium (Pd) precursor to a solution in which carbon particles are dispersed by ultrasound; a second step of adjusting the pH of the solution from the first step to 10 to 12; a third step of purging the solution from the second step with nitrogen and purging with carbon monoxide to produce a solution containing Pd / C particles adsorbed with carbon monoxide; a fourth step of purging the solution from the third step with nitrogen and adding a divalent platinum precursor; and a fifth step of washing and drying the catalyst particles produced by the fourth step to produce particles in which core-shell particles are formed on carbon.

[0024] Korean Patent Registration No. 2398409 (Registration Date: May 11, 2022) relates to a method for manufacturing core-shell particles using carbon monoxide, comprising the steps of adsorbing carbon monoxide onto a transition metal for the core and reacting the carbon monoxide adsorbed on the surface of the transition metal for the core with a metal precursor for the shell and a solvent to form a core-shell structured particle in which a reduced metal shell layer is formed on the transition metal core. This method enables the production of particles through a simple and rapid one-pot reaction, thereby reducing process costs, facilitating scale-up, and allowing for the modification of various types of core and shell metals and the formation of a multilayer shell structure.

[0025] Korean Patent Publication No. 2022-0033545 (Publication Date: Dec. 19, 2024) relates to an apparatus and method for manufacturing core-shell particles utilizing carbon monoxide linked to laser ablation, comprising the steps of adsorbing carbon monoxide onto a transition metal for the core and reacting the carbon monoxide adsorbed on the surface of the transition metal for the core with a metal precursor for the shell and a solvent to form a core-shell structured particle in which a reduced metal shell layer is formed on the transition metal core. This method enables the production of particles through a simple and fast one-pot reaction, thereby reducing process costs, facilitating scale-up, and enabling the modification of various types of core and shell metals and the formation of a multilayer shell structure.

[0026]

[0027] In addition, alloying platinum with nickel (Ni) is known to increase the electrochemically active surface area by increasing the platinum utilization rate and improve performance in oxygen reduction reactions. However, these platinum-nickel alloy catalysts are typically manufactured through a wet process, which is complex and environmentally inefficient. Therefore, there is a need for technology to manufacture and optimize more desirable platinum-based alloy catalysts.

[0028]

[0029] Conventional technology

[0030] Patent Document 1 Republic of Korea Published Patent No. 2023-0169747 (Date of Publication: Dec. 18, 2023)

[0031] Patent Document 2 Republic of Korea Registered Patent No. 10-2291160 (Registration Date: August 11, 2021)

[0032] Patent Document 3 Republic of Korea Registered Patent No. 10-2254764 (Registration Date: May 14, 2021)

[0033] Patent Document 4 Republic of Korea Patent Registration No. 2724367 (Registration Date: Oct. 28, 2024)

[0034] Patent Document 5 Republic of Korea Patent Publication No. 2023-0169749 (Publication Date: Dec. 18, 2023)

[0035] Patent Document 6 Republic of Korea Patent Publication No. 2023-0161557 (Publication Date: Nov. 28, 2023)

[0036] Patent Document 7 Republic of Korea Patent Registration No. 2496278 (Registration Date: Feb. 10, 2023)

[0037] Patent Document 8 Republic of Korea Patent Publication No. 2023-0130846 (Publication Date: Dec. 19, 2024)

[0038] Patent Document 9 Republic of Korea Patent Registration No. 2398409 (Registration Date: May 11, 2022)

[0039] Patent Document 10 Republic of Korea Patent Publication No. 2022-0033545 (Publication Date: Dec. 19, 2024)

[0040]

[0041] The objective of the present invention is to solve the problems of the prior art by resolving the issues of non-uniform distribution and aggregation of platinum-based alloy catalysts, and to provide a method for manufacturing a platinum-based alloy catalyst cost-effectively through a simple and environmentally friendly approach that is stable and has improved electrochemical activity, as well as the platinum-based alloy catalyst manufactured thereby.

[0042]

[0043] Meanwhile, the technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0044] To achieve the above objective,

[0045] One aspect of the present invention provides a method for manufacturing a platinum-based alloy catalyst through a dry process.

[0046] Specifically, the method for manufacturing the platinum-based alloy catalyst of the present invention

[0047] A step of preparing a mixture by mixing a platinum precursor, a transition metal precursor, and a support material without using a solvent (Step 1); and

[0048] The method includes the step (step 2) of heat-treating the above mixture under an inert atmosphere to produce a platinum-based alloy catalyst having a carbon shell.

[0049]

[0050] An embodiment of one aspect of the present invention is characterized in that step 1 involves mixing a platinum precursor, a transition metal precursor, e.g., a nickel precursor, and a support material, e.g., carbon, and ball-milling the mixture to produce a mixture.

[0051] An embodiment of one aspect of the present invention is characterized in that, in step 1, the platinum precursor is platinum acetylacetonate (Pt(acac)2) and the transition metal precursor is Nackel acetylacetonate (Ni(acac)2).

[0052] An embodiment of one aspect of the present invention is characterized in that, in step 2, the inert atmosphere is a nitrogen (N2) atmosphere and the heat treatment is performed at 400 to 800°C.

[0053] An embodiment of one aspect of the present invention is characterized in that, in step 2, the heat treatment temperature is 400 to 500°C, 500 to 600°C, 600 to 700°C, or 700 to 800°C.

[0054] An embodiment of one aspect of the present invention is characterized in that the heat treatment in step 2 is performed at 600°C.

[0055] An embodiment of one aspect of the present invention is characterized in that the platinum alloy has a size of 1 nm to 5 nm.

[0056] An embodiment of one aspect of the present invention is characterized by further including, after step 2, a step of forming a pore structure by performing acid treatment at 600°C and treatment in a 5 mol% H2 / N2 atmosphere.

[0057]

[0058] Another aspect of the present invention provides a platinum-based alloy catalyst produced by the method of the present invention.

[0059] Another embodiment of another aspect of the present invention is characterized in that the platinum-based alloy catalyst has a size of 1 nm to 5 nm, the composition ratio of platinum to transition metal is 3:1 or 1:1, and a pore structure of a carbon shell is formed.

[0060]

[0061] In addition, another aspect of the present invention is

[0062] A step of preparing a mixture by mixing a platinum precursor, a transition metal precursor, and carbon without using a solvent (Step 1); and

[0063] A step (step 2) of heat-treating the above mixture under an inert atmosphere to produce a platinum-based alloy catalyst having a carbon shell,

[0064] A method for manufacturing a platinum-based alloy catalyst is provided.

[0065]

[0066] In addition, another aspect of the present invention provides a platinum-based alloy catalyst produced by the method of the present invention.

[0067]

[0068] According to the present invention, the platinum-based alloy catalyst of the present invention utilizes a transition metal having high solubility in carbon to optimize the carbon shell thickness and ensure stable distribution to prevent aggregation. Additionally, by forming a porous structure, it can enhance mass transferability and catalyst durability while exhibiting excellent electrochemical activity in the oxygen reduction reaction (ORR). Furthermore, by using the method of the present invention through a dry process, the platinum-based alloy catalyst can be manufactured simply, environmentally friendly, and with high productivity.

[0069]

[0070] Figure 1 is a graph showing a schematic diagram of the manufacturing method of the present invention, heat treatment conditions, and XRD experimental data under 3:1 and 1:1 conditions of platinum and nickel.

[0071] Figure 2 is a graph showing the XRD, TGA, DSC, and melting point measurement analysis experimental data of platinum and nickel under 1:1 conditions measured according to real-time (in-situ) temperature.

[0072] Figure 3 shows TEM analysis experimental data of platinum and nickel under 1:1 conditions measured according to real-time (in-situ) temperature.

[0073] Figure 4 is a photograph and graph showing experimental data on particle size distribution under a 3:1 condition of platinum and nickel.

[0074] Figure 5 is a photograph and graph showing experimental data on particle size distribution under 1:1 conditions of platinum and nickel.

[0075] Figure 6 is a graph showing experimental data for TGA experiments under 1:1 and 3:1 conditions of platinum and nickel.

[0076] Figure 7 is a graph and table showing experimental data on crystal size, etc., before and after post-treatment under 1:1 and 3:1 conditions of platinum and nickel.

[0077] Figure 8 is a photograph and graph showing the particle size distribution after post-processing.

[0078] Figure 9 is a graph and photograph showing XRD, TGA, TEM, and EDS experimental data after post-processing.

[0079] Figure 10 is a graph and table comparing electrical activity before and after post-treatment under heat treatment temperature conditions of 600℃.

[0080] Figure 11 shows TEM experimental data measured in SE mode and TE mode under 1:1 conditions for platinum and nickel.

[0081] Figure 12 is a graph and table showing XPS experimental data after post-treatment under 1:1 and 3:1 conditions of platinum and nickel.

[0082] Figure 13 is a graph showing electrochemical experimental data before and after post-treatment under 1:1 and 3:1 conditions of platinum and nickel.

[0083] Figure 14 is a graph showing the results of a durability test after post-treatment under a heat treatment temperature of 600℃.

[0084] Figure 15 is a photograph and graph showing the change in particle size distribution of the control group Pt / C after the durability test.

[0085] Figure 16 is a photograph and graph showing the change in particle size distribution after durability testing by post-treatment under a heat treatment temperature of 600℃.

[0086] Figure 17 shows XRD experimental data of small and large batch samples obtained by post-treatment under a heat treatment temperature of 600℃.

[0087] Figure 18 shows TEM experimental data of small and large batch samples obtained by post-treatment under a heat treatment temperature of 600℃.

[0088] Figure 19 shows the XRD and TEM experimental data of a sample with a 1:1 ratio of Pt and transition metal obtained under a heat treatment temperature of 600℃.

[0089] Figure 20 is a table showing the XRD analysis results and crystallographic characteristics of Pt3M / C_400 (M=Al, Ce, Co, Cu, Fe, La, Mn, V, Y).

[0090] Figure 21 is a table showing the XRD analysis results and crystallographic characteristics of Pt3M / C_800 (M=Al, Ce, Co, Cu, Fe, La, Mn, V, Y).

[0091] Figure 22 shows the TEM and EDS analysis results of the Pt3M / C_400 (M=Al, Ce, Co, Cu, Fe, La, Mn, V, Y) catalyst.

[0092] Figure 23 shows the TEM and EDS analysis results of the Pt3M / C_800 (M=Al, Ce, Co, Cu, Fe, La, Mn, V, Y) catalyst.

[0093] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a skilled expert in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0094] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0095]

[0096] The present invention will be described in detail below.

[0097]

[0098] One aspect of the present invention provides a method for manufacturing a platinum-based alloy catalyst through a dry process.

[0099] Specifically, the method for manufacturing the platinum-based alloy catalyst of the present invention

[0100] A step of preparing a mixture by mixing a platinum precursor, a transition metal precursor, and a support material without using a solvent (Step 1); and

[0101] The method includes the step (step 2) of heat-treating the above mixture under an inert atmosphere to produce a platinum-based alloy catalyst having a carbon shell.

[0102]

[0103] FIG. 1 is a schematic diagram illustrating the manufacturing method of the present invention, which will be explained in detail step by step below.

[0104]

[0105] Step 1 involves preparing a mixture by mixing a platinum precursor, a transition metal precursor, and a support material without using a solvent.

[0106] The platinum precursor serves as a source for a platinum-based alloy catalyst, and in the present invention, Pt(acac)2, Pt(CH3)4, Pt(C6H5)4, Pt(CO)4, bis(dibenzylideneacetone)platinum(0), tetrakis(triphenylphosphine)platinum(0), MeCpPtMe3, Pt(acac)2, (H2NCH2CH2NH2)PtCl2, [C6H 10[NH2]PtCl2, PtCl2, or H2Pt(OH)6 can be used, and preferably Pt(acac)2 can be used.

[0107] The transition metal precursor is a precursor of a transition metal selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Y, Zr, Pb, Bi, In, Ga, Mg, La, Ce, and Gd; as an example, a nickel precursor can be used. These transition metals can provide effects such as an increase in the active surface area of ​​the platinum catalyst, improved performance of the oxygen reduction reaction, and enhanced catalyst durability through alloying with platinum.

[0108] As an example, nickel is a metal characterized by having high solubility, and in the present invention, its addition can optimize the carbon shell thickness and ensure the stability of nanoparticles, and through the alloying of platinum and nickel, it can increase the active surface area of ​​platinum and improve performance in the oxygen reduction reaction. In the present invention, Ni(acac)2 or a Ni precursor containing various organic ligands can be used as a nickel precursor, and preferably, Ni(acac)2 can be used.

[0109] The support material is a material that covers the surface of the platinum-based alloy catalyst, and any support material having the above function can be used, and it is preferable to use carbon powder.

[0110] In the present invention, the three components are mixed, and it is preferable that the mixing ratio is ultimately Pt:transition metal (e.g., Ni) = 3:1 or 1:1.

[0111]

[0112] Any mixing device that can be conventionally used in the field may be used, and the present invention is not specifically limited thereto.

[0113] Subsequently, the mixture can be placed in a ball mill device and ball-milled to produce a mixture of small particles. In addition to ball milling, simple mixing methods such as hand mixing can also be used.

[0114] The ball mill device may be a ball mill device that is commonly used in the field.

[0115] The ball milling time can be appropriately adjusted by a person skilled in the art, and is preferably 1 to 2 hours, preferably 1 hour.

[0116]

[0117] Step 2 involves heat-treating the mixture under an inert atmosphere to produce a platinum-based alloy catalyst having a carbon shell.

[0118] The mixture prepared in Step 1 above is placed in a container and transferred to a heat treatment device.

[0119] The heat treatment is performed under an inert atmosphere, which can be performed under an argon (Ar) atmosphere or a nitrogen (N2) atmosphere, and preferably under a nitrogen (N2) atmosphere.

[0120] The heat treatment can be performed at a temperature of 200 to 800°C, preferably at one or more temperatures selected from the group consisting of 200 to 300°C, 300 to 400°C, 400 to 500°C, 500 to 600°C, 600 to 700°C, and 700 to 800°C, more preferably at a temperature of 400 to 800°C, 400 to 500°C, 500 to 600°C, 600 to 700°C, or 700 to 800°C, 400°C, 500°C, 600°C, 700°C, or 800°C, and even more preferably at 600°C. If the above range is exceeded, problems may arise in which the physical properties and electrochemical activity of the platinum-based alloy catalyst decrease due to heat treatment.

[0121] The heat treatment time can be appropriately adjusted according to the temperature, and the present invention does not specifically limit this.

[0122]

[0123] The platinum-based alloy catalyst prepared in step 2 above has the form of Pt3Ni / C or PtNi / C, and has a particle size of 1 nm to 5 nm, preferably 1.5 nm to 4 nm. This allows for uniform distribution and can resolve aggregation problems (see FIGS. 4 and 5).

[0124] The manufactured platinum-based alloy catalyst has a carbon shell formed on its surface, and the thickness of this carbon shell can be optimized depending on the addition of a transition metal, preferably 0.5 nm or less.

[0125] Specifically, under heat treatment conditions of 400℃, a platinum-nickel alloy begins to form and can exhibit optimal electrochemical performance, and

[0126] Under heat treatment conditions of 600℃, a stable carbon shell is formed and alloying is completed.

[0127]

[0128] In addition, after step 2, a step of forming a pore structure by performing acid treatment at 600°C and treatment in a 5 mol% H2 / N2 atmosphere may be additionally included.

[0129] Acid washing of the catalyst is performed to effectively remove nickel compounds from the catalyst surface, improve mass transfer characteristics, and minimize nickel leaching. This is intended to resolve nickel leaching issues that may occur during catalyst slurry preparation or fuel cell operation, and to prevent leached nickel from accelerating the degradation of the ionomer or electrolyte and causing performance degradation. Specifically, 0.2 g of the catalyst sample is placed in a mixed solution of 0.1 M HClO4 (600 mL) and ethanol (200 mL) and subjected to ultrasonic stirring at 85°C for 2 hours. Afterward, the mixture is filtered through a membrane filter and dried in a vacuum oven at 60°C for 24 hours.

[0130] Hydrogen atmosphere treatment is performed to restore the catalyst structure weakened by acid treatment and to improve the catalyst surface properties. During this process, platinum (Pt) migrates to the outer layer of the catalyst particles based on surface energy differences, forming a Pt-rich shell. Additionally, the heat treatment stabilizes the thin and uniform carbon shell structure, thereby enhancing catalyst performance and durability. The acid-treated sample is further heat-treated at 600°C for 6 hours in an atmosphere of H2 / N2 mixed gas (v / v = 5 / 95), and then cooled naturally to room temperature.

[0131] As a result of acid treatment and hydrogen atmosphere heat treatment, the particle size of the catalyst samples (Pt3Ni@C / C, PtNi@C / C) increased slightly, but the metal content and elemental composition did not change significantly. These treatments effectively removed nickel compounds from the catalyst surface and contributed to improving mass transfer characteristics. In addition, the carbon shell was formed as a thin, defect-containing structure, which was advantageous for increasing oxygen diffusion and accessibility to the catalytic active site. The Pt-rich shell formed during the heat treatment process played an important role in improving the electrochemical performance of the catalyst particles.

[0132] As a result of scaling up the same acid and heat treatment processes to a 2 g scale, the same particle size, distribution, and elemental composition as the small-scale sample were maintained. This demonstrates that the process is suitable for mass production and shows the commercial potential of catalyst fabrication.

[0133]

[0134] Through these additional steps, an additional porous structure is formed, which can enhance mass transferability and catalyst durability.

[0135]

[0136] The present invention focuses on systematically verifying the structural changes in the carbon shell according to the heat treatment temperature and the resulting performance and durability by manufacturing a carbon shell-coated platinum catalyst (Pt@C / C) on a gram scale using a simple and economical dry process, as described in the examples below, and applying it as a fuel cell electrode catalyst. Pt(acac)2, Ni(acac)2, and carbon black were mixed, and the precursor powder was homogenized through ball milling. Subsequently, heat treatment was performed under various temperature conditions ranging from 200°C to 800°C in a nitrogen atmosphere. The Pt@C / C catalyst synthesized through this process exhibited controlled carbon shell thickness and structure depending on the heat treatment temperature, and showed a form in which small, uniform platinum nanoparticles, mainly 2 to 4 nm in size, were stably dispersed on a carbon support.

[0137] In particular, detailed observation of the morphological changes of the carbon shell according to the heat treatment temperature through in-situ heating TEM analysis revealed that at 200°C, a thin, amorphous carbon shell of less than 1 nm was formed on the surface of platinum nanoparticles, while at 400°C, the carbon shell partially decomposed and changed to cover only a portion of the platinum particle surface. Conversely, at temperatures above 600°C, a dense graphene layer was reformed, confirming a stable carbon structure consisting of one and two layers. These changes in the carbon shell directly affect the platinum active surface area and mass transfer characteristics, suggesting that heat treatment conditions are a key variable for optimizing catalyst performance and durability.

[0138] As a result of electrochemical half-cell evaluations, the Pt@C / C catalysts prepared at 200°C and 400°C exhibited an electrochemical active area (ECSA) similar to that of the commercial Pt / C catalyst (54 m² / g), and demonstrated superior performance, particularly in oxygen reduction reaction (ORR) activity per mass and per area, surpassing the commercial catalyst. This is interpreted as a result of the carbon shell acting to suppress poisoning by the ionomer, in addition to the small and uniform platinum particle size. Furthermore, the carbon shell remained stable even after 30,000 cycles of accelerated durability testing by the U.S. DOE, and changes in platinum particle size were minimized, demonstrating higher durability compared to the commercial Pt / C catalyst.

[0139] The Pt@C / C catalyst produced in this invention is a key material capable of significantly improving fuel cell performance and durability, and it secures both economic feasibility and mass production potential through an innovative dry manufacturing process. This approach is expected to establish itself as a significant technological breakthrough that will ultimately accelerate the realization of hydrogen-based eco-friendly mobility by reducing costs and extending the lifespan of fuel cell stacks.

[0140]

[0141] In addition, another aspect of the present invention provides a platinum-based alloy catalyst produced by the method of the present invention.

[0142] The platinum-based alloy catalyst of the present invention has a size of 1 to 5 nm, preferably 1.5 nm to 4 nm, and exhibits a uniform distribution, which can solve the aggregation problem.

[0143] Furthermore, the platinum-based alloy catalyst of the present invention can optimize the carbon shell thickness by forming an alloy with nickel, which has high solubility for carbon, and can prevent aggregation through stable distribution. Additionally, since a carbon shell is formed on its surface and, preferably, has a porous structure through post-treatment, mass transferability and catalyst durability can be enhanced. At the same time, since it exhibits optimal electrochemical performance, it can be applied and used as a catalyst in fuel cells or oxygen reduction reactions.

[0144]

[0145] In addition, another aspect of the present invention is

[0146] A step of preparing a mixture by mixing a platinum precursor, a transition metal precursor, and carbon without using a solvent (Step 1); and

[0147] A method for preparing a platinum-based alloy catalyst, comprising the step (step 2) of heat-treating the above mixture under an inert atmosphere to prepare a platinum-based alloy catalyst having a carbon shell, and

[0148] A platinum-based alloy catalyst manufactured by the above method is provided.

[0149]

[0150] The details of the process of the present invention will be explained below through examples and experimental examples. These are representative examples related to the present invention, and it should be noted that the scope of application of the present invention cannot be limited solely by these examples.

[0151]

[0152] <Example 1> Preparation of the platinum-based alloy catalyst of the present invention

[0153] Step 1: Prepare the mixture

[0154] 20.823 g of Pt(acac), 20.537 g of Ni(acac), and 0.520 g of carbon powder were added to a mixing container, and then mixed for 10 minutes using a stirrer to ensure uniform mixing. The mixed sample was then ball-milled using a ball-milling device (FRITSCH PULVERISETTE 7 Planetary Micro Mill). A 45 mL zirconium oxide container was used for ball milling, and five 10 mm diameter zirconia balls and ten 5 mm diameter zirconia balls were added. Ball milling was performed for 30 minutes at a rotational speed of 350 rpm, followed by an additional 30 minutes in the opposite direction under the same conditions to prepare the mixture.

[0155]

[0156] Step 2: Heat Treatment

[0157] A platinum-based alloy catalyst was prepared by performing the above mixture under an N2 atmosphere at 200°C, 300°C, 400°C, 500°C, 600°C, or 800°C for 1 to 2 hours.

[0158]

[0159] Step 3: Post-processing

[0160] For post-treatment, 0.2 g of the heat-treated catalyst was placed in a solution of 0.1 M HClO4 (600 mL) and ethanol (200 mL) and sonicated at 85°C for 2 hours, filtered using a hydrophobic PTFE membrane filter, and dried in a vacuum oven at 60°C for 24 hours. The dried sample was heat-treated at 600°C for 6 hours in an H2 / N2 (v / v = 5 / 95) mixed gas atmosphere and then naturally cooled to room temperature to prepare the final catalyst, which was named PtxNi@C / C (x=1,3) according to its composition.

[0161]

[0162] <Experimental Example 1> Characterization of the platinum-based alloy catalyst of the present invention

[0163] (1) Analysis of the size and distribution of platinum-based alloy catalysts and the characteristics of carbon shells

[0164] The structure, nanoparticle size and distribution, and nanoparticle uniformity of the platinum-based alloy catalyst prepared in Example 1 were confirmed through XRD (X-Ray Diffraction; D-max 2500, Rigaku), TEM (Transmission Electron Microscopy, F200, JEOL), and STEM (Scanning Transmission Electron Microscopy; HF5000, HITACHI) analysis.

[0165] The crystal structure, lattice constant, and crystal size of the catalyst were analyzed using an X-ray diffraction (XRD, D-max 2500, Rigaku). The size, shape, and distribution of catalyst particles were analyzed using a transmission electron microscope (TEM, F200, JEOL), and the chemical composition and distribution of specific elements were confirmed through mapping using an energy dispersive spectroscopy (EDS). The positional distribution of alloy nanoparticles within a carbon support was investigated using transmission electron (TE) and scanning electron (SE) modes of a scanning transmission electron microscope (STEM, HF5000, HITACHI), and the arrangement of individual atoms and elemental distribution were confirmed through EDS mapping and line profile analysis using a high-resolution STEM (Spectra Ultra, Thermo Fisher).

[0166] The chemical composition and oxidation state of each element of the synthesized alloy nanoparticles were analyzed using inductively coupled plasma photoemission spectroscopy (ICP-OES, AVIO500, PerkinElmer) and X-ray photoelectron spectroscopy (XPS, NEXSA G2, ThermoScientific). In-situ XRD (SmartLab High Temp XRD, Rigaku) ​​analysis was performed in a nitrogen atmosphere to confirm structural changes with temperature changes and to determine the alloying temperature. The in-situ XRD analysis was conducted by measuring the range from 10° to 80° at a scan rate of 10° / min and heating from 25°C to 1000°C at a rate of 5°C / min.

[0167] In-situ TEM (JEM-ARM200F, JEOL) analysis was performed to elucidate the synthesis mechanism of alloy catalyst particles by observing nanometer-scale structural changes in real time under specific conditions. This analysis involved observing structural changes in nanoparticles in real time while heating from 25°C to 1000°C in a vacuum and then cooling back down to 25°C.

[0168] A thermogravimetric analyzer (TGA, TGA 550, TA), a differential scanning calorimeter (DSC, DSC 131, EVO), and a melting point measuring instrument (SMP 50, Cole-Parmer) were used to evaluate thermal properties and phase changes. TGA analysis was performed in an air atmosphere with a gas flow rate set to 10 cc / min, heating from 25°C to 800°C at a rate of 10°C / min. DSC analysis was conducted in a nitrogen atmosphere over a temperature range of 30–550°C at a rate of 5°C / min. Melting point measurements were performed under air conditions over a temperature range of 30–600°C at a rate of 5°C / min.

[0169]

[0170] Temperature (°) Peak Position (°) (111) Crystalline Size (nm) 400 41.2 1 1.5 5500 41.2 0 1.7 6600 41.2 0 1.9 4700 41.2 2 2.0 8800 41.2 4 2.2 5900 41.2 6 2.5 11000 41.2 6 3.0 325 41.4

[0171]

[0172] Pt3Ni / C Temperature (°) Peak Position (°) (111) Crystalline Size (nm) Lattice Constant (Å) MM Distance (Å) Metal Content (ICP) XRD (111) TEMP t(at%) Ni(at%) 200-------400 40.18 2.03 2.36±0.63.88 52.74 675.55 24.45 600 40.42 2.19 2.20±0.53.86 22.73 75.41 24.59 800 40.54 2.54 2.78±0.73.85 12.72 376.08 23.92

[0173] PtNi / C Temperature (°) Peak Position (°) (111) Crystalline Size (nm) Lattice Constant (Å) MM Distance (Å) Metal Content (ICP) XRD (111) TEMP t(at%) Ni(at%) 200-------400 41.2 21.7 0 1.9 1±0.4 3.7 9 12.6 80 50.1 84 9.8 2600 41.4 6 2.0 0 2.2 7±0.5 3.7 6 92.6 6 54 9.9 35 0.0 7 800 41.4 22.4 32.4 3±0.6 3.7 7 32.6 6 50.9 94 9.0 1

[0174] Sample peak position (°) (111) Crystalline size (nm) Lattice constant (Å) MM distance (Å) Elemental composition (ICP) XRD (111) TEMP t(at%) Ni(at%) Pt3Ni / C_200-------Pt3Ni / C_400 40.18 2.03 2.36±0.6 3.88 52.74 69 1.1(75.6) 8.9(24.5) Pt3Ni / C_600 40.42 2.19 2.20±0.5 3.86 22.73 9 1.3(76.0) 8.7(24.0) Pt3Ni / C_800 40.54 2.54 2.78±0.7 3.85 12. 72391.4(76.1)8.6(23.9)PtNi / C_200-------PtNi / C_40041.221.701.91±0.43.7912.68077.0(50.2)23.0(49.8)PtNi / C_60041.462.002.27±0.53.7692.66549.9350.07PtNi / C_80041.422.432.43±0.63.7732.66777.6(51.0)22.4(49.0)

[0175]

[0176] Sample Metal Content (at%) PtNi Pt3Ni / C_600 75.99 24.01 Pt3Ni@C / C 75.41 24.59 PtNi / C_600 50.12 49.88 PtNi@C / C 49.93 50.07

[0177]

[0178] The physical and chemical properties of the PtNi alloy catalyst change depending on the heat treatment temperature and composition. According to Table 1, which shows the crystallite size and (111) peak position of the PtNi alloy catalyst, as the heat treatment temperature increases, the peak position gradually increases from 41.21° (400°C) to 41.26° (1000°C), which means that the lattice has contracted slightly. At the same time, the crystallite size increases from 1.55 nm to 3.03 nm, showing that the particle size increases at high temperatures.

[0179] Table 2 presents the characteristics of the Pt3Ni / C catalyst according to the heat treatment temperature (200°C–800°C). The peak position increased from 40.18° (400°C) to 40.54° (800°C), and the crystallite size increased from 2.03 nm (400°C) to 2.54 nm (800°C) in XRD analysis, with TEM data showing a similar trend. The lattice constant decreased from 3.885 Å (400°C) to 3.851 Å (800°C), reflecting lattice shrinkage due to heat treatment and alloying. The metal content was approximately 75% Pt and 25% Ni, which is in good agreement with the theoretical alloy composition.

[0180] According to Table 3, which shows the characteristics of the PtNi / C catalyst, the peak position shifted significantly from 41.22° (400°C) to 41.42° (800°C), suggesting that compressive stress was applied due to the increased nickel content. The crystallite size increased from 1.70 nm (400°C) to 2.43 nm (800°C), and the lattice constant decreased from 3.791 Å (400°C) to 3.773 Å (800°C), reflecting structural stabilization due to heat treatment. The metal content shows a uniform alloy composition with Pt and Ni each accounting for approximately 50%.

[0181] Table 4 compares the characteristics of the Pt3Ni / C and PtNi / C catalysts. The peak position of Pt3Ni / C was 40.18° (400°C), which was lower than that of PtNi / C at 41.22° (400°C); this indicates that the higher nickel content in PtNi / C resulted in greater compressive stress. The crystallite size of Pt₃Ni / C (2.03–2.54 nm) was larger than that of PtNi / C (1.70–2.43 nm), which is interpreted as nickel contributing to grain size stabilization. The lattice constants of both catalysts decreased with increasing temperature, and the values ​​for Pt3Ni / C (3.885–3.851 Å) and PtNi / C (3.791–3.773 Å) demonstrate that alloying was well achieved. The metal content shows a difference in composition, with Pt3Ni / C having 75% Pt : 25% Ni and PtNi / C having 50% Pt : 50% Ni.

[0182] According to Table 5, which provides a comparison of the final metal content, the Pt3Ni / C and PtNi / C catalysts maintained stable compositions after acid treatment and subsequent heat treatment. Pt3Ni / C showed no significant change with Pt 75.99% and Ni 24.01%, while Pt3Ni@C / C maintained a stable composition with Pt 75.41% and Ni 24.59%. PtNi / C showed a balanced composition with Pt 50.12% and Ni 49.88%, and PtNi@C / C maintained a stable composition even after post-treatment with Pt 49.93% and Ni 50.07%.

[0183] Overall, the Pt3Ni / C and PtNi / C catalysts maintained stable alloy compositions and structures at high temperatures even during heat treatment and post-treatment processes. Pt3Ni / C exhibited larger lattice constants and peak positions due to its higher Pt content, while PtNi / C contributed to structural stabilization due to its higher Ni content. These characteristics enhance the activity and durability of the catalysts and demonstrate that heat treatment temperature and alloy composition have a significant influence on the crystal size, lattice constant, and metal content of the catalysts.

[0184]

[0185] (2) Electrochemical analysis of the platinum-based alloy catalyst of the present invention

[0186] The electrochemical properties of the platinum-based alloy catalyst prepared in Example 1 were evaluated through ECSA (Electrochemical Surface Area), MA (Mass Activity), and SA (Specific Activity) analysis.

[0187]

[0188] The results were evaluated using a 3-electrode system (BioLogic, VSP-3e) equipped with a rotating disk electrode (RDE). Cycle voltamogram (CV) measurements were performed in a 0.1 M HClO4 solution saturated with N2 at a scan rate of 20 mV / s in the range of 0.03 V to 1.1 V (vs. RHE). The ECSA of each sample was calculated based on the proton adsorption current peak area (1 molar hydrogen adsorption current: 210 μC / cm²) from the CV curve. Oxygen reduction reaction (ORR) performance was evaluated by measuring linear sweep voltamograms (LSV) at a rotation speed of 1600 rpm in a 0.1 M HClO4 solution saturated with O2 at a scan rate of 10 mV / s in the range of 0.05 V to 1.1 V (vs. RHE). MA and SA were calculated by dividing the current density value obtained at 0.9 V from the obtained LSV curve by the platinum content and platinum surface area used in the electrode.

[0189]

[0190] Binding energy (eV) Pt 4f 7 / 2 Pt 0 Pt 4f 7 / 2 Pt 2+ Pt 4f 7 / 2 Pt 4+ Pt 4f 5 / 2 Pt 0 Pt 4f5 / 2 Pt 2+ Pt 4f 5 / 2 Pt 4+1Pt / C71.1572.4074.8174.4275.8778.252Pt3Ni@C / C71.1872.3074.8574.4975.8078.353PtNi@C / C71.2072.3074.8574.4975.8078.35

[0191]

[0192] Sample AST Cycle ESCA(m 2 g -1 pt )MA@0.9V(Amg -1 pt )SA @ 0.9V(mA cm -2 pt ) Half-wave potential (mV) Initial rate of change (%) Initial rate of change (%) Initial rate of change (%) Pt / c Initial 5 4.02 -0.226 -0.419 -888 10k 4 2.32 -21.66 0.138 -38.94 0.327 -21.968 69 30k 3 3.62 -37.76 0.133 -41.15 0.396 -5.498 63 PT3Ni@C / C Initial 68.87 -0.433 -0.628 -906 10k 7 6.84 +11.72 0.407 -6.01 0.529 -15.769 630k 7 2.11 +4.71 0.381 -12.01 0.529 -15.769 460k 69 .77+1.310.398-8.080.570-9.2490490k61.09-11.300.351-18.940.575-8.44904PtNi@C / CInitial77.74-0.404-0.519-90310k77.90+0.240.348-13.90 .447-13.8789930k71.30-8.250.379-6.190.531+2.3190260k68.45-11.9 20.383-5.200.559+7.7190190k64.98-16.380.384-4.950.590+13.68901

[0193]

[0194] Table 7 shows the durability and electrochemical performance changes of Pt / C, Pt3Ni@C / C, and PtNi@C / C catalysts. For the Pt / C catalyst, the ECSA in the accelerated degradation test (AST) was an initial value of 54.02 m 2 g -1 Pt33.62 m after 90,000 cycles 2 g -1 Pt It decreased by approximately 37.76%, while MA and SA decreased by 41.15% and 5.49%, respectively. The half-wave potential decreased by 25 mV from an initial 888 mV to 863 mV, and these results show that the performance of the Pt / C catalyst deteriorated rapidly and its durability was low during the degradation test.

[0195] On the other hand, the Pt3Ni@C / C catalyst had an initial ECSA value of 68.87 m 2 g -1 Pt 69.76 m after 90,000 cycles 2 g -1 Pt It increases by 1.31%, showing almost no deterioration. MA is an initial 0.433 A mg -1 Pt 0.351 A mg at -1 Pt It decreased by 18.94%, and SA was an initial 0.628 mA cm -2 Pt At 0.570 mA cm -2 Pt It decreased by 9.25%. The half-wave potential decreased by 2 mV from the initial 906 mV to 904 mV, demonstrating excellent durability.

[0196] For the PtNi@C / C catalyst, the initial ECSA is 77.90 m 2 g -1 Pt 64.98 m after 90,000 cycles 2 g -1 Pt Although it decreased by 16.38%, MA was initially 0.404 A mg -1 Pt 0.395 A mg at -1 Pt The reduction rate is very low at 2.23%. SA is an initial 0.519 mA cm -2 Pt At 0.590 mA cm-2 Pt It increased by 13.68%, indicating increased exposure of the active site. The half-wave potential decreased by 2 mV from an initial 903 mV to 901 mV, showing durability similar to Pt3Ni@C / C.

[0197] Table 6 shows the results of analyzing the electronic structures of Pt / C, Pt3Ni@C / C, and PtNi@C / C catalysts through their Pt 4f binding energies. The Pt binding energies of Pt3Ni@C / C and PtNi@C / C increased slightly compared to Pt / C, indicating that the electron density of Pt decreased slightly due to interactions with Ni. This suggests that interactions with Ni shifted the d-band center of Pt downward, thereby adjusting the adsorption energy in the oxygen reduction reaction (ORR) and contributing to improved catalytic performance.

[0198] Overall, Pt3Ni@C / C and PtNi@C / C exhibit superior durability and performance compared to Pt / C, playing a crucial role in performance enhancement by adjusting the electronic structure of Pt through interactions with Ni. In particular, Pt3Ni@C / C demonstrated excellent characteristics in maintaining ECSA and minimizing MA reduction rates, while PtNi@C / C exhibited unique properties by optimizing the exposure of the active site through increased SA.

[0199]

[0200] When mixing platinum, transition metal precursors, and carbon supports using a dry process, uniform mixing is difficult because no solvent is used, and there is a possibility that platinum and transition metal precursors may aggregate, leading to non-uniform catalyst particle sizes. This can result in a reduction in the active surface area of ​​the catalyst, which may degrade electrochemical performance, and there is also a concern that the physical durability of the catalyst may be compromised due to non-uniform dispersion. While these issues were resolved in conventional wet processes by using solvents for mixing and dispersion, a new method is required in dry processes because such steps are absent.

[0201] Experimental data demonstrated that the platinum-based alloy catalyst produced through the dry process presented in this invention did not exhibit the aforementioned anticipated problems. XRD and TEM analysis results showed that the particle size of the catalyst produced through the dry process was uniformly distributed within the range of 1 to 5 nm. In the case of platinum-nickel alloys (Pt3Ni / C and PtNi / C), the sizes were 2.2 ± 0.5 nm and 2.3 ± 0.6 nm, respectively, confirming that uniform dispersion was achieved. Furthermore, in the electrochemical performance evaluation, the ECSA (Electrochemical Surface Area) was measured at 77.71 m² / g, indicating performance equivalent to that of catalysts produced by the conventional wet process. The MA (Mass Activity) and SA (Specific Activity) were also measured at 0.404 A / mg and 0.519 mA / cm², respectively, satisfying the criteria for a high-performance catalyst. In the durability test results, the catalyst post-treated at 600℃ showed minimal change in particle size and maintained stable catalytic properties.

[0202] These results provide the basis for how the process conditions of the present invention were able to solve anticipated problems. Heat treatment was performed at 400 to 800°C in an inert atmosphere to induce alloy formation and uniform distribution, and particle aggregation was prevented by stabilizing the carbon shell at temperatures above 600°C. In addition, mass transferability and catalyst durability were further enhanced by forming a porous structure through acid treatment and hydrogen atmosphere treatment steps. In particular, as nickel alloys with platinum through the interaction between the nickel precursor and the carbon support, the platinum utilization rate increases and the electrochemically active surface area of ​​the catalyst is expanded, and both the electrochemical activity and stability of the catalyst are improved by optimizing the carbon shell thickness.

[0203] The reason the above-mentioned problems do not occur while using a dry process in the present invention is presumed to be due to a combination of factors, such as heat treatment conditions, interactions between materials, nanoparticle stabilization, and the optimization of post-treatment steps. By optimizing heat treatment conditions and using a temperature of 400 to 800°C and an inert gas, platinum and transition metal precursors are rearranged and alloyed. This process induces a uniform particle distribution and contributes to preventing aggregation. In particular, high-temperature heat treatment promotes the formation of a carbon shell, thereby blocking inter-particle bonding and providing physical stability.

[0204] The strong interaction between the carbon support and the precursor also plays a significant role. It is highly likely that the high surface area and chemical properties of the carbon support facilitated the uniform distribution of platinum and transition metal precursors. Furthermore, transition metal precursors, such as nickel acetylacetonate, alloy with platinum, which may have contributed to inhibiting particle growth and stabilizing their size. This process helps increase the active surface area of ​​platinum alloy nanoparticles and enhance catalytic performance through changes in electronic structure.

[0205] Acid treatment and hydrogen atmosphere treatment during the post-processing stage further optimize the surface properties of nanoparticles and form pore structures, thereby improving mass transferability. These pore structures likely contributed to strengthening the durability of the catalyst and maintaining the uniformity of catalyst particle size. In particular, the alloying of platinum and nickel can have the effect of preventing aggregation and inhibiting particle growth through the modification of the crystal structure.

[0206] In conclusion, the dry process of the present invention demonstrates that, despite the absence of solvent use, a catalyst with a uniform particle distribution, high electrochemical performance, and excellent durability can be produced through the complex interaction between heat treatment conditions, post-treatment steps, and material properties. This can be viewed as an important example proving the potential for environmentally friendly and efficient catalyst manufacturing using a dry process.

[0207]

[0208] In addition, looking at the XRD analysis results in Fig. 20, the graphs on the left and right show the data for the Pt-Al, Pt-Ce, Pt-Co, Pt-Cr, and Pt-Cu samples, and the Pt-Fe, Pt-La, Pt-Mn, Pt-V, and Pt-Y samples, respectively. Each graph represents the XRD intensity according to the 2-Theta (°) value of the sample, which allows for the confirmation of the crystal structure of the Pt3M alloy catalyst. Characteristic diffraction peaks of the Pt (111) plane are observed in all samples, indicating whether an alloy of Pt and a transition metal has formed. Furthermore, subtle changes in the peak position and intensity of Pt appear depending on the type of transition metal, which indicates that the lattice constant has changed due to alloying.

[0209] The data shown in the table of Fig. 20 summarize the crystallographic characteristics of each sample. Peak Position (°) (111) indicates the diffraction peak position of the Pt (111) crystal plane and shows slight variations depending on the type of transition metal. For example, a peak appears at 39.53° for Pt-Al / C and at 39.93° for Pt-Co / C. This is determined by the atomic size of the transition metal and the degree of alloying of Pt. Crystalline size (nm) is the grain size calculated using the Scherrer formula, and for example, Pt-Al / C shows a size of 1.88 nm, and Pt-V / C shows a size of 1.24 nm. Small crystal size is closely associated with high catalytic activity. Lattice constant (Å) indicates the lattice constant in the Pt crystal structure and shows the deformation of the crystal structure due to the addition of transition metals. For example, the lattice constant of Pt-Ce / C is 3.943 Å, and that of Pt-V / C is 3.959 Å. In addition, the MM distance (Å) represents the average distance between metals, and it is measured to be 2.789 Å for Pt-Al / C and 2.788 Å for Pt-Ce / C.

[0210] This experiment is conducted with a total metal content of 50 wt% (Pt: 45 wt%, M: 5 wt%) by heat treatment at 400°C for 2 hours in a nitrogen (N2) atmosphere. These conditions appear to be optimal for the alloying of Pt and transition metals and the stabilization of the crystal structure. The experimental results confirm the possibility that smaller grain sizes increase the surface area of ​​the catalyst, thereby enhancing electrochemical activity, while lattice constants and MM distances play a crucial role in evaluating alloy formation and structural stability. Furthermore, XRD peak shifts and crystallographic changes indicate the degree of alloying between Pt and transition metals, suggesting that if alloying is successful, activity in the oxygen reduction reaction (ORR) may be enhanced.

[0211]

[0212] Looking at the XRD analysis results in Fig. 21, the graph on the left shows the XRD patterns of Pt-Al, Pt-Ce, Pt-Co, Pt-Cr, and Pt-Cu catalysts, and the graph on the right shows the XRD patterns of Pt-Fe, Pt-La, Pt-Mn, Pt-V, and Pt-Y catalysts. The graph shows the XRD intensity according to the 2-Theta (°) value, and characteristic diffraction peaks of the Pt (111) plane are observed in all samples. This indicates whether alloying occurs between Pt and transition metals, and shows that alloying occurs more distinctly and crystal structure stabilization appears under heat treatment conditions of 800°C. Depending on the type of transition metal (M), the position and intensity of the Pt (111) peak appear differently, which reflects changes in metal atom size and the degree of alloy formation.

[0213] Analyzing the table data in Fig. 21, the peak position (°) (111) represents the diffraction peak position of the Pt (111) crystal plane. For example, Pt-Al / C shows a peak at 39.90° and Pt-Co / C at 40.02°, showing a slight shift depending on the atomic size of the transition metal and the degree of alloying of Pt. The crystallite size (nm) is the grain size calculated using the Scherrer formula, and is 2.36 nm for Pt-Al / C and 2.02 nm for Pt-V / C. As the heat treatment temperature increases, the grain size increases, which affects the electrochemical activity and stability of the catalyst. The lattice constant (Å) represents the lattice constant of the Pt crystal structure, and is 3.925 Å for Pt-Ce / C and 3.907 Å for Pt-V / C. This indicates that the lattice constant is modified due to the addition of the transition metal and serves as a key indicator of alloy formation. In addition, the MM distance (Å) represents the average distance between metals, which is 2.764 Å for Pt-Al / C and 2.750 Å for Pt-La / C. This demonstrates the difference in distance between metals depending on the type of transition metal and the alloy structure.

[0214] This experiment was conducted by heat treating at 800°C for 2 hours under a nitrogen (N2) atmosphere under conditions of a total metal content of 50 wt% (Pt: 45 wt%, M: 5 wt%). This high-temperature heat treatment strengthens the alloying between Pt and transition metals and helps stabilize the crystal structure. XRD data can confirm alloy formation and changes in the crystal structure through the shift of the Pt (111) peak, which directly affects the physical properties of the catalyst, particularly its durability and activity.

[0215] Increases in grain size and changes in lattice constants serve as important indicators for evaluating the balance between catalytic activity and stability. Changes in MM distance represent structural changes resulting from the addition of transition metals, which can significantly influence catalytic performance in electrochemical reactions such as the oxygen reduction reaction (ORR). Consequently, it is demonstrated that Pt-M alloy catalysts can achieve excellent physical stability and electrochemical performance through high-temperature heat treatment. In particular, crystal structure stability and the degree of alloying are expected to play important roles in catalyst design and application.

[0216]

[0217] Examining the TEM analysis results of the Pt-Al / C, Pt-Ce / C, Pt-Co / C, Pt-Cr / C, and Pt-Cu / C catalysts in Figs. 22 and 23, the 50 nm scale TEM images clearly reveal the microstructure of the catalysts. In each sample, nanoparticles are evenly distributed on the carbon support, and the particle size appears mostly uniform. These particle sizes range from approximately 1 to 5 nm, which matches the grain size confirmed by XRD analysis, suggesting that the carbon shell structure formed during the heat treatment process plays a role in stabilizing the nanoparticles. The 10 nm scale TEM images allow for clearer observation of the catalyst particles, indicating that the alloying of platinum and transition metals is well-established. The catalyst particles are dispersed on the surface of the carbon support, confirming structural characteristics that prevent aggregation.

[0218] EDS analysis visually displays the elemental distribution of Pt (green) and transition metals (M; red). This confirms that an alloy structure is formed in which Pt and transition metal elements are evenly mixed. For example, an even distribution of Pt and Al is observed in Pt-Al / C, while an even distribution of Pt and Cu is observed in Pt-Cu / C. This uniform elemental distribution is expected to enhance the electrochemical activity of the catalyst and provide stable catalytic properties.

[0219] Meanwhile, TEM analysis results of the Pt-Fe / C, Pt-La / C, Pt-Mn / C, Pt-V / C, and Pt-Y / C catalysts show that 50 nm scale TEM images reveal uniformly dispersed nanoparticles existing in a stable alloy form under heat treatment conditions. These nanoparticles maintain strong interactions with the carbon support, supporting the structural stability of the catalyst. The 10 nm scale TEM images more clearly show the shape and size of the nanoparticles, confirming that the size is maintained between 1 and 5 nm. This indicates that alloying between Pt and transition metals has been well achieved and that aggregation is minimal.

[0220] EDS analysis results show a uniform elemental distribution of Pt (green) and transition metals (M; red), demonstrating the success of alloy formation. For example, an even distribution of Pt and Fe is observed in Pt-Fe / C, while an even distribution of Pt and Y is observed in Pt-Y / C. This elemental distribution is expected to contribute to improving the durability and mass transfer performance of the catalyst.

[0221] In summary, the two figures demonstrate that the Pt3M / C catalyst formed a stable and uniform alloy structure under heat treatment conditions of 400°C through TEM and EDS analysis. The TEM images highlight the uniform size and distribution of nanoparticles, which are expected to have a positive impact on electrochemical activity and catalyst durability. Furthermore, the EDS mapping results confirm that Pt and transition metals are evenly distributed, demonstrating successful alloying, which is expected to contribute to improved catalyst performance. This catalyst is highly likely to exhibit excellent performance in applications such as fuel cells, and it is determined that optimal structure and properties have been secured through heat treatment conditions and alloying.

[0222] The platinum-based alloy catalyst of the present invention utilizes a transition metal having high solubility in carbon to optimize the carbon shell thickness and ensure stable distribution to prevent aggregation. Additionally, by forming a porous structure, it enhances mass transferability and catalyst durability while exhibiting excellent electrochemical activity in the oxygen reduction reaction (ORR). Furthermore, since the platinum-based alloy catalyst can be manufactured simply, environmentally friendly, and with high productivity using the method of the present invention through a dry process, it has industrial applicability.

Claims

A step of preparing a mixture by mixing a platinum precursor, a transition metal precursor, and a support material without using a solvent (Step 1); and A step (step 2) of heat-treating the above mixture under an inert atmosphere to produce a platinum-based alloy catalyst having a carbon shell, Method for manufacturing a platinum-based alloy catalyst. A method according to claim 1, characterized in that step 1 involves mixing a platinum precursor, a transition metal precursor, and a support material and performing ball milling to produce a mixture. A method according to claim 1, characterized in that, in step 1, the platinum precursor is platinum acetylacetonate (Pt(acac)2) and the transition metal precursor is Nackel acetylacetonate (Ni(acac)2). A method according to claim 1, characterized in that in step 2, the inert atmosphere is a nitrogen (N2) atmosphere and the heat treatment is performed at 400 to 800°C. A method according to claim 4, characterized in that the heat treatment temperature in step 2 is 400 to 500℃, 500 to 600℃, 600 to 700℃, or 700 to 800℃. A method according to claim 4, characterized in that the heat treatment in step 2 is performed at 600℃. A method according to claim 1, characterized in that the platinum alloy has a size of 1 nm to 5 nm. A method according to claim 1, characterized by additionally including, after step 2, a step of forming a pore structure by performing acid treatment at 600℃ and treatment in a 5 mol% H2 / N2 atmosphere. Platinum-based alloy catalyst produced by the method of claim 1. A platinum-based alloy catalyst according to claim 9, characterized in that the platinum-based alloy catalyst has a size of 1 nm to 5 nm, the composition ratio of platinum to transition metal is 3:1 or 1:1, and a pore structure of a carbon shell is formed. A step of preparing a mixture by mixing a platinum precursor, a transition metal precursor, and carbon without using a solvent (Step 1); and A step (step 2) of heat-treating the above mixture under an inert atmosphere to produce a platinum-based alloy catalyst having a carbon shell, Method for manufacturing a platinum-based alloy catalyst. Platinum-based alloy catalyst produced by the method of claim 11.

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