Electrode catalyst for fuel cell and method for producing the same

Abstract

To provide a catalyst for a fuel cell in which activity and durability of the catalyst are improved by alloying not the whole but only a part of the catalyst for the fuel cell, and to provide a method of manufacturing the same.SOLUTION: According to an aspect of the present invention, there is provided an electrode catalyst for a fuel cell including a platinum-based catalyst, wherein the platinum-based catalyst has a triple core-shell structure, platinum is included in each of a core and a shell layer, and a platinum transition metal alloy is included in an intermediate layer disposed between the core and the shell layer, and a method of preparing the same. The electrode catalyst for a fuel cell according to the present invention has a triple core-shell structure by preparing colloidal platinum particles in a solution and alloying a transition metal on the surface of the catalyst, and the electrode catalyst has excellent dispersibility and durability.SELECTED DRAWING: Figure 1

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention relates to an alloy electrode catalyst for fuel cells and a method for producing the same, and more particularly to a platinum-based core-shell alloy catalyst supported on carbon that has high activity and durability, and a method for producing the same.

[0002] The national research and development projects that supported this invention are as follows:

[0003] Project unique number: 1415186363 Project number: 20020437 Ministry in charge: Ministry of Trade, Industry and Energy Issue management organization: Korea Institute for Industrial Technology Evaluation and Management Research project name: Development of innovative nano-fusion product technology Research title: Development of hydrogen electric vehicle fuel cell module technology based on platinum alloy nanocatalyst production with MEA platinum usage of less than 0.2gkW Project execution organization: The Carbon Studio Co., Ltd. Research period: January 1, 2023 to December 31, 2025 Project unique number: 1415185115 Project number: 20022451 Ministry in charge: Ministry of Trade, Industry and Energy Issue management organization: Korea Institute for Industrial Technology Evaluation and Management Research project name: Development of material component technology - package type Research topic: Development of PEM water electrolysis membrane / catalyst production technology Project execution organization: Chemtros Co., Ltd. Research period: January 1, 2023 to December 31, 2025 [Background technology] Fuel cells can be divided into polymer electrolyte membrane fuel cells (PEMFC), direct methanol fuel cells (DMFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), etc. depending on the type of electrolyte and fuel used.

[0004] Polymer electrolyte fuel cells use hydrogen as fuel at low temperatures (usually below 100°C) and produce electrical energy through an electrochemical reaction between the hydrogen and oxygen in the air. These fuel cells are considered environmentally friendly because they produce water (H2O) as a by-product during the electrochemical reaction process.

[0005] A fuel cell is composed of an oxidizing electrode (anode) where fuel is oxidized, a reducing electrode (cathode) where oxygen is reduced, and an electrolyte.

[0006] The hydrogen used as fuel is oxidized at the oxidizing electrode to produce hydrogen ions (H + The electrons generated at the oxidizing electrode generate energy via an external conductor, and the hydrogen ions move to the reducing electrode via the electrolyte. At the reducing electrode, oxygen (O2) supplied from the air reacts with the hydrogen ions transferred from the oxidizing electrode to the electrolyte to produce water (H2O).

[0007] On the other hand, platinum (Pt)-based electrocatalysts, which are stable and have excellent oxygen reduction reaction properties, are typically used as components of the oxidizing and reducing electrodes to increase the activity of the oxygen reduction reaction (ORR).

[0008] Platinum is an expensive precious metal. Therefore, for the commercialization of fuel cell systems, it is necessary to develop a technology to reduce the amount of platinum used in the electrodes, and a technology to reduce the amount of platinum used by increasing the chemical activity of platinum itself through the incorporation of a transition metal alloy into platinum particles is essential.

[0009] Such alloy catalysts generally have improved activity compared to platinum. However, alloy catalysts have different particle growth rates due to the difference between the platinum reduction rate and the transition metal reduction rate during the synthesis process. As a result, alloy catalysts are less dispersible on the carbon support than platinum catalysts, making it difficult to expect improvements in initial performance. Furthermore, there is a risk of a sudden drop in performance due to the elution of transition metals caused by voltage changes during operation of the fuel cell system.

[0010] In order to increase the activity of the catalyst itself and solve the problem of transition metal leaching, much research has been conducted on the development direction of existing alloy catalysts, focusing on structural changes to the catalyst rather than simply alloying.

[0011] In the US20230395818A1 patent, a PtCo alloy catalyst or a PtCoMn alloy catalyst is configured as an inner core, and a Pt shell is configured on the outside. The different structures of the inside and outside are calculated through lattice parameter measurements, and the catalyst shows better activity than platinum catalysts (Pt).

[0012] In addition, US20120316054A1 patent predicts that the inner core is made of Ag, Ni or an alloy of these, and the outer shell is made of Pt, making it a noble metal catalyst without a support and with a particle size of 20nm, with excellent activity.

[0013] The conventional technology is a patent for a double core-shell type alloy catalyst in which only platinum exists on the surface, and the interior is made up of a platinum alloy catalyst. This has problems such as poor catalyst dispersion on carbon and large catalyst particle size that inhibits catalyst activity, making it difficult to ensure performance and durability at a commercial level.

[0014] [Summary of the Invention] [Problem to be solved by the invention] The object of the present invention is to provide an oxygen reduction reaction catalyst for a fuel cell in order to solve the above problems, and to improve the activity and durability of the catalyst by alloying only a portion of the catalyst for a fuel cell, rather than the entire catalyst.

[0015] However, the technical problem of the present invention is not limited to this, and includes parts that can be clearly understood by a person having ordinary skill in the technical field to which the present invention pertains from the following description.

[0016] [Means for solving the problem] According to one embodiment, there is provided an electrode catalyst for a fuel cell comprising a platinum-based catalyst, the platinum-based catalyst having a triple core-shell structure, the core and shell layers each containing platinum, and an intermediate layer located between the core and shell layers containing a platinum-transition metal alloy.

[0017] The transition metal may be one or more selected from the group consisting of Fe, Co, Ni, Ti, V, Mn, Cu, Zr, Mo, and W.

[0018] The platinum content in the core may be 90 to 95 wt % of the total platinum content in the entire fuel cell electrode catalyst, the platinum content in the intermediate layer may be 5 to 9 wt % of the total platinum content in the entire fuel cell electrode catalyst, and the platinum content in the shell layer may be 0.5 to 1 wt % of the total platinum content in the entire fuel cell electrode catalyst.

[0019] The content of the transition metal may be 33 to 100 wt % based on the total content of platinum contained in the electrode catalyst.

[0020] The platinum catalyst may be supported on carbon.

[0021] The amount of the platinum catalyst supported on the crystalline carbon may be 20 to 90% by weight.

[0022] According to another embodiment, there is provided a method for manufacturing an electrode catalyst for a fuel cell including a platinum-based catalyst, the method including the steps of dispersing carbon in a polyol solvent to prepare a first dispersion, heating a platinum precursor dissolved in the polyol solvent to prepare colloidal platinum particles, preparing a mixed solution of the first dispersion and the colloidal platinum particles, adding a transition metal precursor to the mixed solution and heating it to prepare a catalyst with a double core-shell structure, and washing and filtering the double core-shell catalyst and performing a post-treatment process to prepare a catalyst with a triple core-shell structure.

[0023] The dual core-shell structure may include platinum in the core and a platinum-nonmetallic alloy in the shell layer.

[0024] In the manufacturing method, the triple core-shell structure may contain platinum in each of the core and shell layers, and a platinum-transition metal alloy in an intermediate layer located between the core and shell layers.

[0025] In the manufacturing method, the platinum content in the core may be 90 to 95 wt % of the platinum content in the entire fuel cell electrode catalyst, the platinum content in the intermediate layer may be 5 to 9 wt % of the platinum content in the entire fuel cell electrode catalyst, and the platinum content in the shell layer may be 0.5 to 1 wt % of the platinum content in the entire fuel cell electrode catalyst.

[0026] In the above-described production method, the transition metal may be one or more selected from the group consisting of Fe, Co, Ni, Ti, V, Mn, Cu, Zr, Mo, and W.

[0027] The post-processing step may include a freeze-drying step under vacuum.

[0028] In the production method, the content of the transition metal may be 33 to 100 wt % with respect to the total content of platinum contained in the electrode catalyst.

[0029] In the step of producing colloidal platinum particles, the heating temperature may be 90 to 130°C.

[0030] In the step of preparing the catalyst having a double core-shell structure, the heating temperature may be 200 to 250°C.

[0031] Before washing the dual core-shell catalyst, it may undergo at least one of a heat treatment and an acid treatment process.

[0032] The heat treatment may be carried out at a temperature of 300 to 900° C. in a vacuum, hydrogen, nitrogen or argon atmosphere.

[0033] The acid treatment may be carried out in 0.5 to 1 M nitric acid at a temperature of 60°C to 100°C.

[0034] [Effects of the invention] The fuel cell electrode catalyst according to the present invention has a triple core-shell structure in which the core and shell layers contain platinum and the intermediate layer between the core and shell layers contains a platinum-non-metallic alloy, thereby ensuring both catalyst dispersibility and durability.

[0035] The method for manufacturing an electrode catalyst for a fuel cell according to the present invention involves preparing colloidal platinum particles in a solution and alloying a transition metal on the surface of the catalyst to obtain a triple-layer catalyst with excellent dispersibility and durability.

[0036] [Brief description of the drawing] FIG. 1 is a diagram schematically illustrating the triple core-shell structure of an electrode catalyst for a fuel cell according to the present invention. FIG. 2 is a flowchart illustrating a method for producing an electrode catalyst for a fuel cell according to the present invention. FIG. 3 is a TEM photograph of the colloidal state of the catalysts according to Examples 1 to 3. FIG. 4 shows TEM photographs of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2. FIG. 5 is a TEM-EDX photograph of the catalyst according to Example 2. FIG. 6 shows XRD results of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2. FIG. 7 shows the results of ORR and catalyst durability, which show the electrochemical effects of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2. FIG. 8 shows the results of the cell voltage performance and catalyst durability of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2.

[0037] [Mode for Carrying Out the Invention] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention; FIG. 2 is a block diagram of a semiconductor device according to an embodiment of the present invention; FIG. 3 is a block diagram of a semiconductor device according to an embodiment of the present invention;

[0038] As used herein, the term "platinum particles" may refer to both primary platinum particles and secondary platinum particles in the form of particle structures formed by the aggregation of a plurality of primary platinum particles.

[0039] An electrode catalyst for a fuel cell according to one embodiment will be described below.

[0040] According to one embodiment, there is provided an electrode catalyst for a fuel cell comprising a platinum-based catalyst, The platinum-based catalyst has a triple core-shell structure, and the core and shell layers each contain platinum, and the intermediate layer located between the core and shell layers contains a platinum-transition metal alloy.

[0041] The fuel cell electrode catalyst according to the present invention has a triple core-shell structure.

[0042] Here, the triple core-shell structure refers to a three-layered three-dimensional structure consisting of 1) the innermost part of the catalyst, i.e., the core, 2) the outermost part of the catalyst, i.e., the shell layer located at the outermost shell, and 3) an intermediate layer located between the core and the shell layer.

[0043] The following description will be given with reference to FIG.

[0044] Referring to FIG. 1, the core and shell layers of the fuel cell electrode catalyst contain platinum.

[0045] The content of platinum contained in the core may be 90 to 95 wt % of the total content of platinum contained in the entire electrode catalyst for a fuel cell.

[0046] The intermediate layer located between the core and the shell layer contains a platinum-transition metal alloy, and the transition metal may be, for example, one or more selected from the group consisting of Fe, Co, Ni, Ti, V, Mn, Cu, Zr, Mo, and W, but is not limited thereto.

[0047] The content of platinum in the intermediate layer may be 5 to 9 wt % based on the total weight of platinum in the fuel cell electrode catalyst, but is not limited thereto.

[0048] In the intermediate layer, it is not necessary for all of the platinum and transition metal to be alloyed, and a portion of the platinum and transition metal may be present in the form of a composite that is not an alloy but is merely a physical bond.

[0049] The shell layer, which is the outermost layer of the intermediate layer, contains platinum, and its content may be, but is not limited to, 0.5 to 1 wt % of the total platinum content contained in the fuel cell electrode catalyst.

[0050] The electrode catalyst for a fuel cell according to the present invention includes a platinum catalyst having a triple structure, which reduces the amount of expensive platinum by alloying transition metals, while treating the shell layer with platinum to prevent an increase in platinum surface roughness caused by dissolution of the transition metal. In other words, the use of the platinum catalyst according to the present invention can ensure both catalytic activity and durability.

[0051] In one embodiment, the content of the transition metal in the electrode catalyst may be, but is not limited to, 33 to 100 wt % of the total platinum content in the electrode catalyst. If the amount of the transition metal is too small beyond the above range, it is difficult to control the size, shape, and dispersion of the platinum via the transition metal. If the amount of the transition metal precursor is too large, some of the transition metal particles reduced in the final stage may be present in the outermost layer of the catalyst, which is undesirable.

[0052] The platinum-based catalyst may be supported on carbon.

[0053] There are no limitations on the carbon material as long as it is a carbon material with a porous structure that can support metal particles.

[0054] The amount of platinum particles supported in the electrode catalyst for a battery may be 20 to 90 wt %, more specifically 30 to 80 wt %, based on the total weight of the electrode catalyst. The electrode catalyst according to the present invention is not only capable of supporting a large amount of platinum metal particles, but also, as can be seen from the following experimental examples, has a small average particle size of platinum, a small standard deviation of particle size, and is evenly dispersed in the crystalline carbon support, with almost no aggregation observed, thereby ultimately exhibiting excellent electrochemical properties.

[0055] According to another embodiment of the present invention, there is provided a method for producing a fuel cell electrode catalyst including a platinum-based catalyst.

[0056] The method for producing an electrode catalyst for a fuel cell according to the present invention will be described below with reference to FIG.

[0057] Referring to FIG. 2, a method for manufacturing a fuel cell electrode catalyst including a platinum-based catalyst according to the present invention includes the steps of: a) dispersing carbon in a polyol solvent to prepare a first dispersion; b) separately heating a platinum precursor dissolved in a polyol solvent to prepare colloidal platinum particles; c) preparing a mixed solution of the first dispersion and the colloidal platinum particles; d) adding a transition metal precursor to the mixed solution and heating it to prepare a catalyst having a double core-shell structure; and e) washing and filtering the double core-shell catalyst and performing a post-treatment process to prepare a catalyst having a triple core-shell structure.

[0058] According to the production method of the present invention, colloidal platinum particles are formed in a solution, a transition metal precursor is applied to the surface of the platinum particles to form platinum-transition metal alloy particles on the surface of the platinum particles, and then the transition metal is eluted onto the surface to obtain a triple-structure core-shell catalyst in which only platinum is present in the outermost particles.

[0059] According to the present invention, the amount of expensive platinum used can be reduced by alloying platinum and transition metals. However, by alloying only a portion of the catalyst rather than the entire catalyst, it is possible to reduce the phenomenon of increased platinum surface roughness during the dealloying process in which the transition metal is dissolved, resulting in a decrease in durability, and the decrease in catalytic activity due to an increase in particle size caused by high-temperature heat treatment during the alloying process.

[0060] In step a), the first dispersion liquid can be prepared by dispersing carbon in a polyol solvent.

[0061] There are no limitations on the crystalline carbon, so long as it is a carbon material with a porous structure that can support metal particles.

[0062] The polyol acts as a solvent and a reducing agent to reduce the metal precursor. The polyol may be, but is not limited to, at least one selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, and glycerol. Specifically, the polyol may be ethylene glycol, which is inexpensive, easily oxidized to glycolaldehyde at high temperatures, and has strong reducing power.

[0063] In the present invention, a first dispersion can be prepared by dispersing 100 to 1,000 parts by weight of polyol in 1 part by weight of the carbon. This dispersion can be performed using a physical method such as a homogenizer or ultrasonic device. If the amount of crystalline carbon is high or the amount of polyol is low outside the above ranges, the carbon support particles tend to form clumps and aggregate. If the amount of crystalline carbon is low or the amount of polyol is high, the reaction process efficiency decreases, making it difficult to achieve the intended effects of the present invention. Specifically, a first dispersion can be prepared by dispersing 1 part by weight of the crystalline carbon in 200 to 400 parts by weight of polyol.

[0064] In step b), the platinum precursor dissolved in the polyol solvent is heated to prepare colloidal platinum particles.

[0065] The type and content of the transition metal have already been explained in the section relating to the electrode catalyst of the present invention, and therefore the explanation thereof will be omitted here.

[0066] In the step of preparing the colloidal platinum particles, the heating temperature may be, but is not limited to, 90 to 130°C.

[0067] In preparing the colloidal platinum particles, the ratio of platinum to polyol solvent in the platinum precursor may be, but is not limited to, 1:488 to 1:732. If the ratio of platinum to polyol solvent is less than 1:488, the colloidal platinum particle size increases, resulting in reduced activity. If the ratio of platinum to polyol solvent is greater than 1:732, the colloidal platinum particle size decreases, causing alloying of the core platinum inside, making it difficult to prepare triple core-shell type particles.

[0068] In the step c), the first dispersion obtained in the step a) and the colloidal platinum particles obtained in the step b) are mixed to prepare a mixed solution.

[0069] Next, in step d), a transition metal precursor is added to the mixed solution obtained above, and the mixture is heated to prepare a catalyst having a double core-shell structure (secondary core-shell catalyst).

[0070] Here, the double core-shell structure is a structure in which the core contains platinum and the outer shell layer contains a platinum-non-metallic alloy, and corresponds to the state before the triple-structure catalyst according to the present invention is obtained.

[0071] In the step of preparing the catalyst having a double core-shell structure, the heating temperature may be, but is not limited to, 200 to 250°C.

[0072] Then, in step e), the double core-shell catalyst obtained above is washed and filtered, and a post-treatment process is carried out to prepare a catalyst with a triple core-shell structure.

[0073] Here, the dual core-shell catalyst may be subjected to heat treatment and / or acid treatment after filtering and washing. The heat treatment may be performed at a temperature of 300 to 900°C in a vacuum, hydrogen, nitrogen, or argon atmosphere for 4 to 8 hours, but is not limited thereto. The acid treatment may be performed in 0.5 to 1 M nitric acid at a temperature of 60 to 100°C for 2 to 6 hours, but is not limited thereto.

[0074] After washing and filtering in step e), a post-treatment process is carried out, which may be a freeze-drying process under vacuum. After completing this post-treatment process, a platinum-based catalyst having a triple core-shell structure according to the present invention is obtained. Through step e), the transition metal on the surface of the double core-shell structure catalyst (secondary core-shell catalyst) is dissolved, leaving only platinum on the surface of the catalyst.

[0075] The molar ratio of the transition metal to platinum present in the double core-shell structure catalyst (secondary core catalyst) may be, but is not limited to, 1:6 to 1:1.

[0076] Other details regarding the triple structure have been described above, and therefore, redundant description will be omitted here.

[0077] The present invention will be described in detail below with reference to examples. However, the following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

[0078] Electrocatalyst production Example 1 A platinum colloidal solution was prepared by placing 6.336 g of platinum precursor (10 wt%, (MEA)2Pt(OH)6·xH2O, TMI Chem. Co.), 0.387 g of dispersant (50 wt% NaH2PO2·H2O in H2O), and 435.3 g of ethylene glycol (EG) in a reflux-type glass reactor at 90 °C for 4 hours.

[0079] Add 0.75g of carbon (420m 2 / g, crystal size 3.1 nm) and ultrasonic / high speed mixing for 30 minutes to produce a platinum colloidal particle and carbon dispersion.

[0080] 9.38 g of cobalt precursor (4 wt% CoCl2 in EG, Sigma-Aldrich) is added to the dispersion and stirred for about 60 minutes to prepare an alloy catalyst dispersion.

[0081] The dispersion was placed in an autoclave reactor equipped with a stirrer, and the temperature of the reactor was raised to about 250° C. to carry out a reduction reaction. After the reaction was completed, a filtration / washing process was repeated to obtain a slurry, which was then dried in a vacuum oven at 250° C. for 4 hours to prepare a catalyst composition.

[0082] After the drying process was completed, the catalyst composition was heat-treated in a heat treatment furnace in a hydrogen gas atmosphere at 600°C for 6 hours, and then acid-treated in 1M nitric acid at 90°C for 4 hours, followed by filtration and washing. The catalyst sample was placed in a freeze-drying apparatus and freeze-dried under vacuum to obtain the final electrode catalyst (Pt@PtCo@Pt / C-1).

[0083] Example 2 An electrode catalyst (Pt@PtCo@Pt / C-2) was prepared in the same manner as in Example 1, except that the platinum colloidal solution was prepared at 110°C to change the size of the colloidal platinum particles.

[0084] Example 3 An electrode catalyst (Pt@PtCo@Pt / C-3) was prepared in the same manner as in Example 1, except that the platinum colloidal solution was prepared at 130°C to change the size of the colloidal platinum particles.

[0085] Comparative Example 1 0.75g of crystalline carbon (420m 2 A crystalline carbon dispersion was prepared by mixing 435.3 g of ethylene glycol (EG) with 4.0 g of platinum precursor (Pt(NH3)4Cl2·xH2O, TMI Chem. Co.) and 0.387 g of dispersant (10 wt% NaH2PO2·H2O in H2O) for approximately 30 minutes.

[0086] These dispersions were mixed and then placed in a glass reactor equipped with a Reflux device, and the temperature of the reactor was raised to about 165°C to carry out the reduction reaction. Once the reaction was completed, the filtration / washing process was repeated to obtain a slurry, which was then dried in a vacuum oven at 250°C for 4 hours to produce a catalyst composition.

[0087] After the drying process was completed, the catalyst composition was heat-treated in a heat treatment furnace in a hydrogen gas atmosphere at 600°C for 6 hours, and then acid-treated in 1M nitric acid at 90°C for 4 hours, followed by filtration and washing. The catalyst sample was placed in a freeze-drying apparatus and freeze-dried under vacuum to obtain the final electrode catalyst (Pt / C).

[0088] Comparative Example 2 0.75g of crystalline carbon (420m 2 A crystalline carbon dispersion was prepared by mixing 435.3 g of ethylene glycol (EG) with 4.5 g of platinum precursor (4 wt%, Pt(NH3)4Cl2·xH2O, TMI Chem. Co.), 0.387 g of dispersant (10 wt% NaH2PO2·H2O in H2O), and 9.38 g of cobalt precursor (4 wt% CoCl2 in EG, Sigma-Aldrich) for approximately 30 minutes.

[0089] The dispersion was placed in an autoclave reactor equipped with a stirrer, and the temperature of the reactor was raised to about 250° C. to carry out the reduction reaction. After the reaction was completed, the filtration / washing process was repeated to obtain a slurry, which was then dried in a vacuum oven at 250° C. for 4 hours to prepare a catalyst composition.

[0090] After the drying process was completed, the catalyst composition was heat-treated in a heat treatment furnace in a hydrogen gas atmosphere at 600°C for 6 hours, and then acid-treated in 1M nitric acid at 90°C for 4 hours, followed by filtration and washing. The catalyst sample was placed in a freeze-drying apparatus and freeze-dried under vacuum to obtain the final electrode catalyst (PtCo@Pt / C).

[0091] Experimental Example 1: TEM image of colloidal platinum catalyst The colloidal catalysts of Examples 1 to 3 were observed by TEM photography, and the results are shown in FIG.

[0092] 3, it can be seen that the colloidal platinum particles according to Examples 1 to 3 were formed uniformly, and that the particle size increased in part as the reaction temperature increased.

[0093] Thus, the uniform platinum particles according to Examples 1 to 3 form platinum-transition metal alloy particles, and it is expected that the degree of dispersion can be improved even within the carbon support.

[0094] Experimental Example 2: TEM image of triple core-shell platinum alloy catalyst The catalysts of Examples 1 to 3 and Comparative Examples 1 and 2 were observed by TEM photographs, and the results are shown in FIG.

[0095] 4, it can be seen that the catalysts of Examples 1 to 3 exhibit superior dispersion compared to the catalysts of Comparative Examples 1 and 2.

[0096] Experimental Example 3: TEM-EDX photograph (structure confirmation) The catalyst of Example 2 was observed by TEM-EDX photography, and the results are shown in FIG.

[0097] From FIG. 5, it can be seen that the catalyst according to Example 2 has a platinum layer in the outermost layer.

[0098] Experimental Example 4: XRD and XRF The XRD and XRF results of the catalysts according to Examples 1 to 3, Comparative Examples 1 and 2 are shown in FIG. 6 and Table 1, respectively.

[0099] 6, the catalysts according to Examples 1 to 3 have a relatively broader distribution of 2θ (39° to 41°) values ​​than the catalysts according to Comparative Examples 1 and 2. This indicates that the Pt and PtCo particles are not uniform in phase, meaning that Pt core and PtCo phases exist simultaneously.

[0100] [Table 1]

[0101] Referring to Table 1, it can be seen that the catalysts according to Examples 1 to 3, which are manufactured with a triple core-shell structure, have smaller particle sizes than the catalysts according to Comparative Examples 1 and 2, which are manufactured with platinum or conventional PtCo. This suggests that the catalysts according to Examples 1 to 3, which are manufactured with a triple core-shell structure, are expected to have excellent electrochemical activity.

[0102] Experimental Example 5: Evaluation results of oxygen reduction reactivity and durability The ORR results showing the electrochemical effects of the catalysts according to Examples 1 to 3, Comparative Example 1 and Comparative Example 2 are shown in FIG.

[0103] [Table 2]

[0104] 7 and Table 2, it can be seen that the catalysts of Examples 1 to 3 are superior in oxygen reduction reaction performance to the catalysts of Comparative Examples 1 and 2. Furthermore, in a durability evaluation under conditions for evaluating catalyst durability, 0.6 to 1.0 V and 10,000 cycles, Example 2 showed a lower rate of decrease relative to the initial performance than Comparative Examples 1 and 2.

[0105] Experimental example 6: Single cell performance The cell voltages according to the current densities, which indicate the electrochemical effects of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2, were measured.

[0106] The results are shown in Figure 8 and Table 3.

[0107] [Table 3]

[0108] 8 and Table 3, it can be seen that the catalyst according to Example 2 has superior voltage performance at the same current density compared to the catalysts according to Comparative Examples 1 and 2. Furthermore, the performance of Example 2 was also superior in voltage evaluation after the catalyst durability test, confirming that it also has superior durability compared to conventional catalysts.

[0109] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to these, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Brief explanation of the drawings]

[0110] [Figure 1] FIG. 1 is a diagram schematically illustrating the triple core-shell structure of an electrode catalyst for a fuel cell according to the present invention. [Figure 2] 1 is a flowchart illustrating a method for producing an electrode catalyst for a fuel cell according to the present invention. [Figure 3] 1 is a TEM photograph of the colloidal state of the catalysts according to Examples 1 to 3. [Figure 4] 1 shows TEM photographs of catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2. [Figure 5] 1 is a TEM-EDX photograph of a catalyst according to Example 2. [Figure 6] 1 shows XRD results of catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2. [Figure 7] 1 shows the results of ORR and catalyst durability showing the electrochemical effects of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2. [Figure 8] 1 shows the results of the cell voltage performance and catalyst durability of the catalysts according to Examples 1 to 3 and Comparative Examples 1 and 2.

Claims

1. An electrode catalyst for a fuel cell comprising a platinum-based catalyst, The platinum-based catalyst is It has a triple core-shell structure, The core and shell layers each contain platinum, An electrode catalyst for a fuel cell, wherein an intermediate layer located between the core and the shell layer contains a platinum-transition metal alloy.

2. 2. The fuel cell electrode catalyst according to claim 1, wherein the transition metal is one or more selected from the group consisting of Fe, Co, Ni, Ti, V, Mn, Cu, Zr, Mo and W.

3. The content of platinum contained in the core is 90 to 95 wt % of the total content of platinum contained in the fuel cell electrode catalyst; The content of platinum contained in the intermediate layer is 5 to 9 wt % based on the total content of platinum contained in the fuel cell electrode catalyst; 2. The fuel cell electrode catalyst according to claim 1, wherein the content of platinum contained in the shell layer is 0.5 to 1 wt % of the total content of platinum contained in the fuel cell electrode catalyst.

4. 2. The fuel cell electrode catalyst according to claim 1, wherein the content of the transition metal is 33 to 100 wt % based on the total content of platinum contained in the electrode catalyst.

5. 2. The fuel cell electrode catalyst according to claim 1, wherein the platinum-based catalyst is supported on carbon.

6. 6. The fuel cell electrode catalyst according to claim 5, wherein the amount of the platinum catalyst supported on the crystalline carbon is 20 to 90% by weight.

7. A method for producing an electrode catalyst for a fuel cell containing a platinum-based catalyst, comprising: Dispersing crystalline carbon in a polyol solvent to prepare a first dispersion; heating a platinum precursor dissolved in a polyol solvent to produce colloidal platinum particles; preparing a mixed solution of the first dispersion and the colloidal platinum particles; adding a transition metal precursor to the mixed solution and heating the mixture to prepare a catalyst having a double core-shell structure; and washing and filtering the double core-shell catalyst and carrying out a post-treatment process to produce a catalyst having a triple core-shell structure.

8. 8. The method for producing an electrode catalyst for a fuel cell according to claim 7, wherein the double core-shell structure contains platinum in the core and a platinum-nonmetallic alloy in the shell layer.

9. The triple core-shell structure is The core and shell layers each contain platinum, 8. The method for producing an electrode catalyst for a fuel cell according to claim 7, wherein an intermediate layer located between the core and the shell layer contains a platinum-transition metal alloy.

10. The content of platinum contained in the core is 90 to 95 wt % of the total content of platinum contained in the fuel cell electrode catalyst; The content of platinum contained in the intermediate layer is 5 to 9 wt % based on the total content of platinum contained in the fuel cell electrode catalyst; 10. The method for producing an electrode catalyst for a fuel cell according to claim 9, wherein the content of platinum contained in the shell layer is 0.5 to 1 wt % of the total content of platinum contained in the electrode catalyst for a fuel cell.

11. 8. The method for producing an electrode catalyst for a fuel cell according to claim 7, wherein the transition metal is one or more selected from the group consisting of Fe, Co, Ni, Ti, V, Mn, Cu, Zr, Mo and W.

12. The method for producing an electrode catalyst for a fuel cell according to claim 7 , wherein the post-treatment step includes a freeze-drying step under vacuum.

13. 8. The method for producing an electrode catalyst for a fuel cell according to claim 7, wherein the content of the transition metal is 33 to 100 wt % based on the total content of platinum contained in the electrode catalyst.

14. 8. The method for producing an electrode catalyst for a fuel cell according to claim 7, wherein the heating temperature is 90 to 130° C. in the step of producing colloidal platinum particles.

15. 8. The method for manufacturing an electrode catalyst for a fuel cell according to claim 7, wherein the heating temperature is 200 to 250° C. in the step of manufacturing the catalyst having a double core-shell structure.

16. 8. The method for producing an electrode catalyst for a fuel cell according to claim 7, wherein the double core-shell catalyst is subjected to both a heat treatment and an acid treatment in a post-treatment process after being washed and filtered.

17. 17. The method for producing an electrode catalyst for a fuel cell according to claim 16, wherein the heat treatment is carried out at a temperature of 300 to 900° C. in a vacuum, hydrogen, nitrogen or argon atmosphere.

18. 17. The method for producing an electrode catalyst for a fuel cell according to claim 16, wherein the acid treatment is carried out in 0.5 to 1 M nitric acid at a temperature of 60° C. to 100° C.

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