Catalyst composition, catalyst support, cathode electrode for fuel cell, fuel cell, and method for producing catalyst composition and method for producing catalyst support

Abstract

To provide a catalyst composition with a platinum-based catalyst which exhibits high ORR activity over a long period of time even in a high-temperature, strong acidic environment, a catalyst support material, a cathode electrode for a fuel battery and a fuel battery, and methods for manufacturing the catalyst composition and the catalyst support material.SOLUTION: A catalyst composition comprises: a platinum-based catalyst; and a salt modified by the platinum-based catalyst, in which the salt including a 1,3,5-triazine derivative cation represented by the general formula (1) below and a perfluoroalkyl sulfonyl imide anion. (In the formula, R1, R2 and R3 represent identical or different substituted or unsubstituted amino groups, substituted or unsubstituted aryl groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups or other basic functional groups. Rf1 and Rf2 represent identical or different perfluoroalkyls.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a catalyst composition having high oxygen reduction reaction activity, a catalyst support, a cathode electrode for a fuel cell, a fuel cell, a method for producing the catalyst composition, and a method for producing the catalyst support. [Background technology]

[0002] Polymer electrolyte fuel cells (PEFCs) generate electrical energy with high efficiency by generating a hydrogen oxidation reaction at the anode and an oxygen reduction reaction at the cathode, and because the only product is water, they are attracting attention as clean energy conversion devices. Platinum (Pt) is used as a catalyst to promote chemical reactions at the anode and cathode of PEFCs. Platinum-based catalysts have the advantages of high catalytic activity and electrical conductivity, as well as being resistant to corrosion by environmental conditions and substances present in the surrounding environment.

[0003] On the other hand, when platinum catalysts are used in PEFCs, the reduction reaction of oxygen gas on the platinum catalyst has a larger activation energy than the oxidation reaction of hydrogen gas, which is a major factor in the voltage drop of PEFCs. Therefore, increasing the oxygen reduction reaction (ORR) activity of platinum-based catalysts has become an important issue. Furthermore, the PEFC cathode is an extremely harsh environment, with a high temperature (approximately 80°C) and a strong acidity (pH approximately 1). Furthermore, the cathode potential fluctuates between 0.6 and 1.0 V vs. the reversible hydrogen electrode (RHE). Platinum, which is stable under normal conditions, is subject to oxidation and reduction. Therefore, the platinum catalyst used in PEFC cathodes undergoes repeated platinum oxide formation and reduction on its surface. This chemical change in the platinum catalyst surface increases the particle size of the platinum catalyst in PEFC cathodes through repeated dissolution and redeposition (Ostwald ripening). Furthermore, the migration and aggregation of platinum catalyst particles increases the particle size, reducing the surface area and reducing the ORR activity. Therefore, improving the durability of platinum catalysts used in PEFCs is an extremely important issue. Therefore, various approaches have been explored to improve the ORR activity and durability of platinum catalysts.

[0004] Non-Patent Document 1 discloses a platinum-based catalyst whose surface is modified with a hydrophobic ionic liquid (protic ionic liquid) consisting of a 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene cation and a bis(trifluoromethanesulfonyl)imide anion. Non-Patent Document 1 discloses that, based on a comparison of cyclic voltammograms (CV) of a platinum-based catalyst modified with this hydrophobic ionic liquid and an unmodified platinum-based catalyst, modifying the platinum-based catalyst with a hydrophobic ionic liquid suppresses the oxidation reaction of platinum in the potential range of 0.7 V to 1.0 V vs. RHE, and that linear sweep voltammogram (LSV) measurements indicate that the ORR activity of the platinum-based catalyst modified with the hydrophobic ionic liquid is improved. Furthermore, Non-Patent Document 1 discloses that the durability of a platinum-based catalyst modified with a hydrophobic ionic liquid was investigated by a potential cycle test in a potential range of 0.6 V to 0.96 V vs. RHE, and that the durability of the platinum-based catalyst was improved by modifying it with a hydrophobic ionic liquid.

[0005] Non-Patent Document 2 discloses a platinum catalyst modified with a hydrophobic ionic liquid (aprotic ionic liquid) consisting of a 1-butyl-3-methylimidazolium cation and a bis(trifluoromethanesulfonyl)imide anion. Non-Patent Document 2 also discloses that CV and LSV measurements show that the oxidation reaction of platinum is suppressed in the potential range of 0.7 V to 1.0 V vs. RHE, resulting in improved ORR activity. Non-Patent Document 2 also discloses that modification with a hydrophobic ionic liquid improves the ORR activity per unit weight (ORR mass activity) of a platinum catalyst from 330 A / g-Pt (at 0.9 V vs. RHE) to 1010 A / g-Pt (at 0.9 V vs. RHE). Furthermore, Non-Patent Document 2 discloses that the durability of the platinum catalyst modified with a hydrophobic ionic liquid was examined in a potential cycle test over a potential range of 0.4 V to 1.1 V vs. RHE, demonstrating improved durability compared to an unmodified platinum catalyst. As described above, Non-Patent Documents 1 and 2 disclose that modifying a platinum-based catalyst with a hydrophobic protic or aprotic ionic liquid can improve the ORR activity and durability of the platinum-based catalyst. However, further improvements in ORR activity and durability are required for platinum-based catalysts to be put to practical use.

[0006] Patent Document 1 discloses an electrochemical oxygen reduction catalyst in which at least one selected from the group consisting of melamine compounds, thiocyanuric acid compounds, and polymers containing melamine compounds or thiocyanuric acid compounds as monomers is supported on a platinum catalyst coated on a glassy carbon (GC) electrode. It also describes that LSV measurements of platinum catalysts with melamine compounds or other compounds adsorbed (supported) on them show improved ORR activity compared to platinum catalysts without melamine compounds or other compounds adsorbed on them. A similar report is also disclosed in Non-Patent Document 3. Non-Patent Document 4 discloses that a palladium core-platinum shell catalyst coated on a GC electrode is modified with melamine or tetra(t-butyl)tetraazaporphine. The CV and LSV of the platinum core-shell catalyst disclosed in Non-Patent Document 4 reveal that platinum oxidation is suppressed at potentials of 0.7 V to 1.0 V vs. RHE in the platinum core-shell catalyst modified with melamine or tetra(t-butyl)tetraazaporphine, improving ORR activity. In particular, the ORR mass activity of the platinum core-shell catalyst modified with melamine is reported to be improved to 3625 A / g-Pt (at 0.9 V vs. RHE). Patent Document 2 discloses an electrochemical oxygen reduction catalyst containing at least one selected from the group consisting of a polymer with a melamine compound as a monomer and a thiol melamine compound, on a platinum catalyst coated on a glassy carbon (GC) electrode. It also discloses that LSV measurements of the platinum catalyst with a melamine compound or the like adsorbed (supported) show improved ORR activity compared to a platinum catalyst without a melamine compound or the like adsorbed. It also discloses that degradation after potential cycling of 0.6 V to 1.0 V vs. RHE is improved compared to an unmodified platinum catalyst. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication WO2019 / 221156 [Patent Document 2] International Publication WO2021 / 090746 [Non-patent literature]

[0008] [Non-Patent Document 1] J. Snyder et al., Nature Material., 9, 904 (2010) [Non-patent document 2] GR Zhang et al., Angew. Chem., Int. Ed. 55, 2257 (2016) [Non-patent document 3] M. Asahi et al., J. Electrochem. Soc., 166, F498 (2019) [Non-patent document 4] S. Yamazaki et al., ACS Catalysis, 10, 14567-14580 (2020) Summary of the Invention [Problem to be solved by the invention]

[0009] Thus, in the platinum-based catalysts modified with melamine or melamine compounds described in Patent Document 1 and Non-Patent Documents 3 and 4, the oxidation reaction of platinum is suppressed at potentials of 0.7 V to 1.0 V vs. RHE, resulting in improved ORR activity compared to unmodified catalysts. However, melamine or melamine compounds are soluble in water; for example, the solubility of melamine in water is 3.1 g / L at 20 °C. Furthermore, because the cathode environment of a PEFC is strongly acidic at a temperature of approximately 80 °C and a pH of approximately 1, the solubility of melamine or melamine compounds, which exhibit weak basicity, is likely to be significantly increased compared to its solubility in water at 20 °C (3.1 g / L). Furthermore, because water is produced by the oxygen reduction reaction at the PEFC cathode, even if a platinum-based catalyst is modified with melamine or melamine compounds, it is likely that the modified catalyst dissolves in the water produced at the cathode and gradually desorbs. Therefore, it is considered difficult to maintain the high activation effect of Pt-based catalysts by modification with melamine or melamine compounds over a long period of time. The present invention has been made in view of the above problems, and aims to provide a catalyst composition including a platinum-based catalyst that exhibits high ORR activity over a long period of time even in the cathode environment of a PEFC, i.e., a high-temperature environment of about 80°C and a strongly acidic environment of about pH 1, a catalyst support, a fuel cell cathode electrode, a fuel cell, a method for producing the catalyst composition, and a method for producing the catalyst support. [Means for solving the problem]

[0010] The inventors focused on the improved ORR activity of platinum-based catalysts modified with melamine or melamine compounds, as disclosed in Patent Document 1 and elsewhere, and aimed to develop a platinum-based catalyst composition that would enable platinum-based catalysts modified with melamine or melamine compounds to maintain their modification effect for a long period of time, even in the cathode environment of a PEFC, i.e., a strongly acidic environment at a temperature of approximately 80°C and a pH of approximately 1. In this invention, they focused on 1,3,5-triazine derivatives or 2,4-diamino-1,3,5-triazine derivatives having a melamine skeleton, and mixed and reacted these melamine derivatives with perfluoroalkylsulfonylimide metal salts, perfluoroalkylsulfonate metal salts, or perfluoroalkylcarboxylate metal salts in an acidic aqueous solution at 80°C and pH 1. As a result, salts consisting of a melamine derivative cation and a perfluoroalkylsulfonylimide anion, a melamine derivative cation and a perfluoroalkylsulfonate anion, or a melamine derivative cation and a perfluoroalkylcarboxylate anion were produced. These salts were found to be insoluble in a strongly acidic environment of 80°C and pH 1, and to be durable enough to exist for a long period in the cathode environment of a PEFC. Furthermore, platinum-based catalysts modified with these salts were found to exhibit higher ORR activity than unmodified catalysts.

[0011] The catalyst composition of the present invention is a catalyst composition comprising a platinum-based catalyst and a salt that modifies the platinum-based catalyst. The salt is characterized by being a salt consisting of a 1,3,5-triazine derivative cation represented by the following general formula (1) and a perfluoroalkylsulfonylimide anion, a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the following general formula (2) and a perfluoroalkylsulfonylimide anion, a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the following general formula (3) and a perfluoroalkylsulfonate anion, or a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the following general formula (4) and a perfluoroalkylcarboxylate anion. In the formula, R1, R2, R3, and R4 are the same or different and represent a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or another basic functional group, and Rf1, Rf2, Rf3, and Rf4 are the same or different and represent a perfluoroalkyl. [ka] [ka] [ka] [ka] In the present invention, the term "salt modified on a platinum-based catalyst" refers to a state in which a salt is adsorbed onto or supported on a platinum-based catalyst, particularly a state in which the platinum-based catalyst is immersed in a liquid in which a salt is dissolved, and then the liquid component is distilled off or dried and evaporated, resulting in the platinum-based catalyst being impregnated with and supported by the salt.

[0012] In the catalyst composition of the present invention, the salts represented by the general formulae (1) to (3) are preferably poorly soluble such that, when 2.74 mmol (rounded to two decimal places) of any of the salts is added to 100 ml of an aqueous perchloric acid solution of pH 1 or 100 ml of an aqueous nitric acid solution of pH 1 and the temperature of these acidic aqueous solutions is raised to 80°C, 50% or more of the salt added precipitates and separates from the acidic aqueous solution. In the catalyst composition of the present invention, the salt represented by the general formula (4) is preferably one that exhibits poor solubility such that, when 2.0 mmol of a 2,4-diamino-1,3,5-triazine derivative constituting the cation of the salt is added to 20 ml of pure water and heated to 80°C, and then 2.0 mmol of a perfluoroalkylcarboxylic acid constituting the cation of the salt and 20 ml of pure water, or 2.0 mmol of a perfluoroalkylcarboxylic acid constituting the cation of the salt and 30 ml of pure water are added, 1.0 mmol or more of the salt precipitates and separates from the aqueous solution.

[0013] In the catalyst composition of the present invention, in the salt represented by the general formula (1) or (2), the perfluoroalkyl of Rf1 and / or Rf2 preferably has 4 or more carbon atoms, and in the salt represented by the general formula (3) or (4), the perfluoroalkyl of Rf3 or Rf4 preferably has more than 4 carbon atoms.

[0014] In the catalyst composition of the present invention, the platinum-based catalyst is preferably a platinum core-shell catalyst consisting of a core particle containing palladium, cobalt, nickel, iron, or copper and a platinum shell formed on the surface of the core particle, or a platinum alloy catalyst containing platinum and palladium, cobalt, nickel, iron, or copper. The catalyst support of the present invention is characterized in that the catalyst composition of the present invention is supported on a porous carbon material as a support.

[0015] The cathode electrode for a fuel cell of the present invention is characterized by comprising the catalyst composition of the present invention or the catalyst support of the present invention. The fuel cell of the present invention is characterized by comprising an anode electrode for a fuel cell and a cathode electrode for a fuel cell of the present invention.

[0016] The method for producing a catalyst composition of the present invention is characterized by contacting a platinum-based catalyst with a modifying solution prepared by dissolving in a polar solvent any one of a salt of a 1,3,5-triazine derivative cation represented by the general formula (1) and a perfluoroalkylsulfonylimide anion, a salt of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (2) and a perfluoroalkylsulfonylimide anion, a salt of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (3) and a perfluoroalkylsulfonate anion, and a salt of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (4) and a perfluoroalkylcarboxylate anion, and then distilling off the polar solvent to modify the platinum-based catalyst with the salt.

[0017] In the method for producing the catalyst composition of the present invention, the salt consisting of the 1,3,5-triazine derivative cation represented by the general formula (1) and the perfluoroalkylsulfonylimide anion is preferably produced by adding a 1,3,5-triazine derivative represented by the following general formula (5) and a perfluoroalkylsulfonylimide metal salt represented by the following general formula (6) to an acidic aqueous solution at 60°C or higher and pH 3 or lower. In the following general formula (5), R1, R2, and R3 are the same or different and represent a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or another basic functional group. In the following general formula (6), Rf1 and Rf2 are the same or different and represent a perfluoroalkyl, and X represents a metal atom. [ka] [ka]

[0018] In the method for producing the catalyst composition of the present invention, the salt consisting of the 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (2) and the perfluoroalkylsulfonylimide anion is preferably produced by adding a 2,4-diamino-1,3,5-triazine derivative represented by the following general formula (7) and a perfluoroalkylsulfonylimide metal salt represented by the following general formula (8) to an acidic aqueous solution at 60°C or higher and pH 3 or lower. In the following general formula (7), R4 represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or another basic functional group. In the following general formula (8), Rf1 and Rf2 represent the same or different perfluoroalkyl groups, and X represents a metal atom. [ka] [ka]

[0019] In the method for producing the catalyst composition of the present invention, the salt consisting of the 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (3) and the perfluoroalkylsulfonate anion is preferably produced by adding a 2,4-diamino-1,3,5-triazine derivative represented by the following general formula (9) and a perfluoroalkylsulfonate metal salt represented by the following general formula (10) to an acidic aqueous solution at 60°C or higher and pH 3 or less. In the following general formula (9), R4 represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or another basic functional group. In the following general formula (10), Rf3 represents a perfluoroalkyl, and X represents a metal atom. [ka] [ka]

[0020] In the method for producing the catalyst composition of the present invention, a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (4) and a perfluoroalkylcarboxylic acid anion is preferably produced by adding a 2,4-diamino-1,3,5-triazine derivative represented by the general formula (11) to an aqueous solution at 60°C or higher containing a perfluoroalkylcarboxylic acid represented by the general formula (12). In the general formula (11), R4 represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or another basic functional group. In the general formula (12), Rf4 represents a perfluoroalkyl group, and X represents a metal atom. [ka] [ka]

[0021] The method for producing a catalyst support of the present invention is a method for producing a catalyst support using the method for producing a catalyst composition of the present invention, and is characterized by bringing the modifying solution into contact with an unmodified catalyst support in which the platinum-based catalyst is supported on a porous carbon material. [Effects of the Invention]

[0022] The catalyst composition of the present invention modifies a platinum-based catalyst with a salt consisting of a 1,3,5-triazine derivative cation or a 2,4-diamino-1,3,5-triazine derivative cation having a melamine skeleton and a perfluoroalkylsulfonylimide anion, a perfluoroalkylsulfonate anion, or a perfluoroalkylcarboxylate anion. This suppresses oxidation of the platinum surface at a potential of 0.7 V to 1.0 V vs. RHE and enhances ORR activity. Furthermore, the salt used in the catalyst composition of the present invention is poorly soluble in strongly acidic aqueous solutions at temperatures above 60°C and below pH 3, allowing the salt modification state to be maintained even in the high-temperature, strongly acidic environment in which PEFCs operate. Therefore, the catalyst composition of the present invention is preferably used as a cathode electrode for a polymer electrolyte fuel cell (PEFC) that exhibits high ORR activity and can maintain that high ORR activity. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing the structure of a cathode electrode containing a catalyst composition of the present invention. [Figure 2] FIG. 1 is a process diagram showing an example of a method for producing a salt used in the catalyst composition of the present invention. [Figure 3] 3a and 3b are cyclic and linear sweep voltammograms, respectively, of the catalyst composition of Example 1. [Figure 4] 4a and 4b are cyclic and linear sweep voltammograms, respectively, of the catalyst composition of Example 2. [Figure 5] 5a and 5b are cyclic and linear sweep voltammograms, respectively, of the catalyst composition of Example 3. [Figure 6] 6a and 6b are cyclic and linear sweep voltammograms, respectively, of the catalyst composition of Example 4. [Figure 7] 7a and 7b are cyclic and linear sweep voltammograms, respectively, of the catalyst composition of Example 5. [Figure 8] 8a and 8b are the cyclic voltammogram and the linear sweep voltammogram of the catalyst composition of Comparative Example 1, respectively. [Figure 9] FIG. 9a is a schematic diagram showing a method for calculating the residual rate of salt, and FIG. 9b is a graph showing the residual rates of Examples 1 to 5 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0024] "Fuel cell cathode catalyst 1" As shown in the schematic diagram of FIG. 1, a cathode catalyst (catalyst support) 1 for a fuel cell comprises a porous carbon support 10 and a catalyst composition. The catalyst composition comprises platinum-based catalyst particles 20 supported on the porous carbon support 10, and a salt 30 that modifies the platinum-based catalyst particles 20. The salt 30 also modifies a portion of the surface of the support 10. However, the salt 30 may also modify only the platinum-based catalyst particles 20, and the catalyst support of the present invention encompasses both concepts. In FIG. 1, the symbol "I" indicates an ionomer. A known ionomer I is used, such as Nafion (registered trademark).

[0025] In a fuel cell equipped with this fuel cell cathode catalyst 1, the hydrogen oxidation reaction shown in the following reaction formula (Equation 1) proceeds in the anode catalyst (not shown), which serves as the counter electrode, generating protons and electrons. The generated protons pass through an ion exchange membrane (not shown) and are supplied from ionomer I to platinum-based catalyst particles 20. It is believed that protons are not only supplied directly from ionomer I to platinum-based catalyst particles 20, but also to platinum-based catalyst particles 20 via proton-conducting salt 30. Meanwhile, electrons generated in the following reaction formula (Equation 1) are supplied from an external circuit to platinum-based catalyst particles 20 via porous carbon support 10. Oxygen gas in the atmosphere passes through the diffusion layer and microporous layer by gas diffusion and is supplied to platinum-based catalyst particles 20 present in the cathode catalyst layer. Oxygen gas is supplied to platinum-based catalyst particles 20 via ionomer I and / or salt 30, and an oxygen reduction reaction (ORR) shown in the following reaction formula (Equation 2) occurs at the cathode electrode 1 to produce water. H2 → 2H + + 2e - ...(Formula 1) 1 / 2O2+ 2H + + 2e - → H2O (Eq. 2)

[0026] "Porous carbon support 10" Examples of the porous carbon support 10 include carbon black, ketjen black, acetylene black, and carbon nanotubes. In particular, porous carbon materials having pore diameters in the mesopore region (2 to 50 nm) are suitable as supports for platinum-based catalyst particles. The porous carbon support 10 should have a specific surface area of ​​500 to 2000 m2 in order to support platinum-based catalyst particles at a high loading rate. 2 / g, especially 1000m 2 / g or more is preferable.

[0027] "Platinum-based catalyst particles 20" The platinum-based catalyst particles 20 are not particularly limited as long as they contain platinum or platinum and a metal other than platinum. Examples of catalysts containing platinum and a metal other than platinum include platinum core-shell catalysts having a core-shell structure with a core made of a metal other than platinum and a platinum shell formed on the surface of the core, and platinum alloy catalysts containing an alloy of platinum and a metal other than platinum. Platinum core-shell catalysts are composed of a core containing palladium, cobalt, nickel, iron, or copper and a platinum shell formed on the surface of the core particle, with palladium being particularly preferred as the core metal. Platinum alloy catalysts are alloys of platinum and a metal other than platinum, such as palladium, cobalt, nickel, iron, or copper, with cobalt or nickel being particularly preferred as the metal other than platinum. The platinum-based catalyst particles 20 are preferably supported in particulate form on the porous carbon support 10. The particle diameter is 20 nm or less, preferably 10 nm or less, and particularly preferably 6 nm or less. The smaller the particle diameter of the platinum-based catalyst particles 20, the greater the area contributing to ORR. However, if the particle diameter is less than 2 nm, the potential fluctuation (0.6 to 1.0 V vs. RHE) occurring in the PEFC cathode tends to cause Ostwald ripening, resulting in an increase in particle diameter. For this reason, the particle diameter of the platinum-based catalyst particles 20 is preferably greater than 2 nm.

[0028] "Salt 30" The first embodiment of the salt 30 is represented by the above general formula (1) and is composed of a 1,3,5-triazine derivative cation and a perfluoroalkylsulfonylimide anion. Salt 30 represented by the general formula (1) above is such that when 2.74 mmol of salt 30 of the first embodiment is added to 100 ml of a perchloric acid aqueous solution having a pH of 1 or 100 ml of a nitric acid aqueous solution having a pH of 1 and the temperature of these acidic solutions is raised to 80° C., a portion of the added salt separates from the acidic aqueous solution. Particularly preferred is one in which 50% or more, 60% or more, 70% or more, and particularly 80% or more of the amount of the added salt separates from the acidic aqueous solution. Specifically, when 2.74 mmol of the 1,3,5-triazine derivative represented by the general formula (5) is added to 100 mL of a perchloric acid solution having a pH of 1 or a nitric acid solution having a pH of 1, the mixture is heated to 80° C., and then 2.74 mmol of a perfluoroalkylsulfonylimide metal salt represented by the general formula (6) is added while maintaining the temperature at 80° C., a portion of the salt 30 formed, which is composed of the 1,3,5-triazine derivative cation represented by the general formula (1) and the perfluoroalkylsulfonylimide anion, is poorly soluble and separates without dissolving in the acidic aqueous solution, i.e., precipitates in the acidic aqueous solution. It is preferable that 50 mol % or more, 60 mol % or more, 70 mol % or more, and particularly 80 mol % or more of the salt 30 represented by the general formula (1) formed in the acidic aqueous solution does not dissolve and separates from the acidic aqueous solution at 80° C., based on the number of moles of the salt or each precursor added.

[0029] The second embodiment of the salt 30 is represented by the above general formula (2) and is composed of a 2,4-diamino-1,3,5-triazine derivative cation and a perfluoroalkylsulfonylimide anion. Salt 30 represented by the general formula (2) above is sparingly soluble, such that when 2.74 mmol of salt 30 of the second embodiment is added to 100 ml of a perchloric acid aqueous solution having a pH of 1 or 100 ml of a nitric acid aqueous solution having a pH of 1 and the temperature of these acidic aqueous solutions is raised to 80° C. Particularly preferred is one in which 50% or more, 60% or more, 70% or more, and particularly 80% or more of the added salt separates from the acidic aqueous solution. Specifically, when 2.74 mmol of the 2,4-diamino-triazine derivative represented by the general formula (7) is added to 100 mL of a perchloric acid solution having a pH of 1 or a nitric acid solution having a pH of 1, the mixture is heated to 80°C, and 2.74 mmol of a perfluoroalkylsulfonylimide metal salt represented by the general formula (8) is added while maintaining the temperature at 80°C, a portion of the salt 30 formed, which is composed of the 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (2) and the perfluoroalkylsulfonylimide anion, does not dissolve in the acidic aqueous solution and separates, i.e., it is poorly soluble, i.e., precipitates in the acidic aqueous solution. Preferably, 50 mol % or more, 60 mol % or more, 70 mol % or more, and particularly 80 mol % or more of the salt 30 represented by the general formula (2) formed in the acidic aqueous solution does not dissolve and separates from the acidic aqueous solution at 80°C, relative to the number of moles of each precursor added.

[0030] The third embodiment of the salt 30 is represented by the above general formula (3) and is composed of a 2,4-diamino-1,3,5-triazine derivative cation and a perfluoroalkylsulfonate anion. Salt 30 represented by the general formula (3) above is poorly soluble, in that when 2.74 mmol of salt 30 of the third embodiment is added to 100 ml of a perchloric acid aqueous solution having a pH of 1 or 100 ml of a nitric acid aqueous solution having a pH of 1 and the temperature of these acidic solutions is raised to 80° C. Particularly preferred is one in which 50% or more, 60% or more, 70% or more, and particularly 80% or more of the added salt separates from the acidic aqueous solution. Specifically, when 2.74 mmol of the 2,4-diamino-1,3,5-triazine derivative represented by the general formula (9) is added to 100 mL of a perchloric acid solution having a pH of 1 or a nitric acid solution having a pH of 1, the mixture is heated to 80°C, and 2.74 mmol of a perfluoroalkylsulfonic acid metal salt represented by the general formula (10) is added while maintaining the temperature at 80°C. A portion of the salt 30 formed, which is composed of the 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (3) and the perfluoroalkylsulfonic acid anion, does not dissolve in the acidic aqueous solution and separates, i.e., it is poorly soluble, i.e., precipitates in the acidic aqueous solution. Preferably, 50 mol % or more, 60 mol % or more, 70 mol % or more, and particularly 80 mol % or more of the salt 30 represented by the general formula (3) formed in the acidic aqueous solution does not dissolve and separates from the acidic aqueous solution at 80°C, relative to the number of moles of each precursor added.

[0031] The fourth embodiment of the salt 30 is represented by the above general formula (4) and is composed of a 2,4-diamino-1,3,5-triazine derivative cation and a perfluoroalkyl carboxylic acid anion. When 2.0 mmol of the 2,4-diamino-1,3,5-triazine derivative represented by general formula (11) is added to 20 mL of pure water, the mixture is heated to 80°C, and then 2.0 mmol of the perfluoroalkylcarboxylic acid represented by general formula (12) and 20 mL or 30 mL of pure water are added while maintaining the temperature at 80°C. The resulting salt 30, composed of the 2,4-diamino-1,3,5-triazine derivative cation represented by general formula (4) and the perfluoroalkylcarboxylic acid anion, is poorly soluble and separates in the acidic aqueous solution. Preferably, at least 1.0 mmol, at least 1.2 mmol, at least 1.4 mmol, and especially at least 1.6 mmol of the salt 30 represented by general formula (4) produced in the acidic aqueous solution is insoluble and separates from the acidic aqueous solution at 80°C.

[0032] The amount of the salt 30 supported is not particularly limited, but is 100% by weight or less, 50% by weight or less, and preferably 20% by weight or less, when the entire catalyst is taken as 100% by weight.

[0033] "1,3,5-triazine derivative cation" In the 1,3,5-triazine derivative cation that forms the cation of salt 30 represented by the above general formula (1), R1, R2, and R3 may be the same or different and may be a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or another basic functional group. Preferred examples of the substituted amino group include an amino group in which one hydrogen atom is substituted with a hydrocarbon group and an amino group in which two hydrogen atoms are substituted with a hydrocarbon group, particularly an amino group substituted with a linear or branched alkyl group or allyl group having 1 to 10 carbon atoms, or more preferably 1 to 6 carbon atoms. Examples of the aryl group include aryl groups such as phenyl, naphthyl, anthracenyl, and tolyl groups (particularly, aryl groups having 6 to 20 carbon atoms, and more particularly, 6 to 18 carbon atoms). The aryl group may also have 1 to 6 (particularly, 1 to 3) substituents such as a nitrogen-containing multi-membered ring, such as an imidazole group, or an amino group. Examples of the alkyl group include lower alkyl groups (particularly straight-chain or branched-chain alkyl groups having 1 to 10 carbon atoms, more particularly 1 to 6 carbon atoms) such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups. The alkyl group may also have 1 to 6 (particularly 1 to 3) substituents, such as a nitrogen-containing multi-membered ring, e.g., an imidazole group, or an amino group. Examples of alkenyl groups include lower alkenyl groups (particularly straight-chain or branched-chain alkenyl groups having 2 to 10 carbon atoms, more particularly 2 to 6 carbon atoms) such as vinyl, allyl, 2-butenyl, 3-butenyl, 1-methylallyl, 2-pentenyl, and 2-hexenyl. The alkenyl group may also have 1 to 6 (particularly 1 to 3) substituents, such as a nitrogen-containing multi-membered ring such as an imidazole group, or an amino group. Preferred examples of the basic functional group include functional groups containing a nitrogen-containing multi-membered ring, such as an imidazole group.

[0034] As the 1,3,5-triazine derivative cation, the 2,4-diamino-1,3,5-triazine cation shown in the above general formula (2) is particularly preferred, where R4 is preferably a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or other basic functional group as described above.

[0035] "Perfluoroalkylsulfonylimide anion" The perfluoroalkylsulfonylimide anion is shown in the general formulas (1) and (2) above. In the formula, Rf1 and Rf2 may be the same or different perfluoroalkyls. At least one of the perfluoroalkyls Rf1 and Rf2 has 2 or more, 3 or more, and preferably 4 or more carbon atoms. It is particularly preferred that both perfluoroalkyls have 4 or more carbon atoms. It is difficult for the above-mentioned 1,3,5-triazine derivative cation alone to survive in the strongly acidic environment of a PEFC cathode (temperature of approximately 80°C, pH of approximately 1). Survival is improved by forming a salt with a perfluoroalkylsulfonylimide anion. Survival becomes evident when the number of carbon atoms on one side of the perfluoroalkylsulfonylimide anion used is 2 or more, 3 or more, and particularly 4 or more. On the other hand, because survival saturates when the number of carbon atoms is 10 or more, from an economical perspective, it is preferable that the number of carbon atoms on one side of the perfluoroalkylsulfonylimide anion is 10 or less.

[0036] "Perfluoroalkylsulfonic acid anion" The perfluoroalkylsulfonate anion is shown in the above general formula (3). In the formula, Rf3 is a perfluoroalkyl. It is difficult for the salt 30 shown in the above general formula (3) to survive in the strongly acidic environment of a PEFC cathode, which has a temperature of about 80°C and a pH of about 1, using only the 2,4-diamino-1,3,5-triazine derivative cation. Forming a salt with a perfluoroalkylsulfonate anion improves survivability. The perfluoroalkylsulfonate anion preferably has 5 or more, 6 or more, 7 or more, or particularly 8 or more carbon atoms, as this enhances survivability. On the other hand, since survivability saturates when the carbon number is 18 or more, from an economical perspective, it is preferable that the perfluoroalkylsulfonate anion has 18 or less carbon atoms.

[0037] "Perfluoroalkyl carboxylic acid anion" The perfluoroalkyl carboxylate anion is shown in the above general formula (4). In the formula, Rf4 is a perfluoroalkyl. It is difficult for the salt 30 shown in the above general formula (4) to survive in the strongly acidic environment of a PEFC cathode, which has a temperature of about 80°C and a pH of about 1, using only the 2,4-diamino-1,3,5-triazine derivative cation. Forming a salt with a perfluoroalkyl carboxylate anion improves survivability. The perfluoroalkyl sulfonate anion preferably has 5 or more, 6 or more, 7 or more, or particularly 8 or more carbon atoms, because this enhances survivability. On the other hand, since survivability saturates when the carbon number is 18 or more, from an economical perspective, the perfluoroalkyl carboxylate anion preferably has 18 or less carbon atoms.

[0038] In this way, fuel cell cathode catalyst (catalyst support) 1 has platinum-based catalyst particles 20 modified with salt 30 composed of a 1,3,5-triazine derivative cation having a melamine skeleton and a perfluoroalkylsulfonylimide anion, or a perfluoroalkylsulfonate anion, or a perfluoroalkylcarboxylate anion, thereby suppressing oxidation of the platinum-based catalyst surface and enhancing ORR activity. Furthermore, because the salt of the present invention is poorly soluble at a temperature of 80°C and in a strongly acidic aqueous solution with a pH of approximately 1, the modification effect of the salt of the present invention can be maintained for a long period of time even when used in a PEFC cathode, which is subject to high temperatures and a strongly acidic environment. The catalyst support of the present invention is not limited to the fuel cell cathode catalyst 1 shown in FIG. 1. For example, the fuel cell cathode catalyst (catalyst support 1) shown in FIG. 1 is composed of a catalyst support provided with a carrier 10 made of a porous carbon material, but it may also be composed of a catalyst support in which a catalyst composition is supported on a carrier made of another porous material that exhibits electrical conductivity. Furthermore, the fuel cell cathode catalyst may not necessarily have a carrier. For example, a catalyst composition may be formed by using a platinum-based catalyst as an electrode without using a carrier, and modifying the platinum-based catalyst with a salt.

[0039] "Method of producing catalyst composition" The method for producing a catalyst composition of the present invention includes the following steps 1 to 4. "Process 1" A salt 30 represented by any one of the above general formulas (1) to (4) is synthesized. "Process 2" The salt 30 represented by any one of the above general formulas (1) to (4) is separated from the acidic aqueous solution. [Process 3] A salt 30 represented by any one of the above general formulas (1) to (4) is dissolved in a polar solvent to prepare a modifying solution. [Step 4] The modifying solution prepared in step 3 is brought into contact with a platinum-based catalyst, and then the polar solvent is distilled off to modify the salt 30 into a platinum-based catalyst.

[0040] Step 1 is a step of synthesizing a salt 30 represented by any one of the above general formulas (1) to (4). The salt 30 represented by any one of the general formulas (1) to (3) is synthesized in an acidic aqueous solution having a pH of 3 or less. The acidic aqueous solution used for salt synthesis preferably has a pH of 3 or less, pH 2 or less, particularly pH 1 or less. Furthermore, an acidic aqueous solution heated to 60°C or higher, 70°C or higher, particularly 80°C or higher is more preferred. For example, an aqueous perchloric acid solution heated to 80°C and having a pH of about 1, or an aqueous nitric acid solution heated to 80°C and having a pH of about 1, can be used. By adjusting the acidic aqueous solution to pH 3 or less, the 1,3,5-triazine derivative can be cationized. In particular, by adjusting the temperature of the acidic solution to 60°C or higher, the cationization of the 1,3,5-triazine derivative can be further promoted. For example, a preferred method (step 1) for producing the salts represented by general formulas (1) to (3) includes mixing a 1,3,5-triazine derivative constituting the cation of each salt and a perfluoroalkylsulfonylimide metal salt or a perfluoroalkylsulfonate constituting the anion of each salt in an aqueous perchloric acid solution at 60°C or higher and pH 3 or lower, or in an aqueous nitric acid solution at 60°C or higher and pH 3 or lower. On the other hand, salt 30 represented by general formula (4) is preferably prepared by adding a 1,3,5-triazine derivative constituting the cation of the salt to an aqueous solution containing a perfluoroalkylcarboxylic acid constituting the anion of the salt at a temperature of 60° C. or higher, 70° C. or higher, and particularly 80° C. or higher. In this case, the pH of the aqueous solution containing the perfluoroalkylcarboxylic acid is 3 or lower, 2 or lower, and preferably 1 or lower.

[0041] In the cathode catalyst composition for fuel cells of the present invention, the salt modifying the platinum-based catalyst must survive in the high-temperature (80°C) and strongly acidic (pH approximately 1) environment that is the operating environment of a PEFC. Therefore, in the cathode catalyst composition of the present invention, an acidic aqueous solution (particularly, a perchloric acid aqueous solution or a nitric acid aqueous solution) heated to 60°C or higher and having a pH of 3 or less is used to synthesize the salt modifying the platinum-based catalyst. This synthesis environment simulates the operating environment of a PEFC. When equimolar amounts of the cation and anion of the salt 30 represented by any one of the general formulas (1) to (4) are added to an acidic aqueous solution in this synthesis environment simulating the operating environment of a PEFC, it is extremely important that the salt is generated and separated in the acidic aqueous solution and exhibits poor solubility in order to survive in the operating environment of a PEFC. Here, poor solubility of the separated salt means that 50% or more of the salt is separated and generated in the acidic aqueous solution based on the number of moles of each precursor added to a given amount of acidic aqueous solution. The concentrations of the cations and anions of the salt 30 represented by any one of the general formulas (1) to (4) in the acidic aqueous solution are not particularly limited, as long as the salt can be separated and produced in the acidic aqueous solution. For example, the lower limit of the concentration is 5 mM or more, 10 mM or more, and preferably 20 mM or more. (The concentration unit "M" indicates "mol / l", and the same applies below.) The upper limit of the concentration is 1000 mM or less, 500 mM or less, and preferably 100 mM or less. Note that the metal cation (X + ) is not particularly limited, but alkali metals such as lithium and potassium are preferred.

[0042] Step 2 is a step of separating the salt represented by any one of general formulas (1) to (4) separated and produced with an acidic aqueous solution. For example, the salt is filtered from the acidic aqueous solution and dried. In this case, since the salt is synthesized under strongly acidic conditions, it is preferable to redisperse the produced salt in pure water, and repeat stirring and filtration 5 to 6 times until the pH of the filtrate reaches a neutral range (e.g., pH 6 to 7). After the pH of the filtrate reaches a neutral range, the separated salt is dried in the air at 60°C for 24 hours. Another method involves dissolving the salt in dichloromethane, separating it from the acidic aqueous solution, and then evaporating the dichloromethane. In this case, after separating and generating the salt in the acidic aqueous solution, dichloromethane (CHCl) is added to the acidic aqueous solution to dissolve the generated salt in the dichloromethane phase. The supernatant is then removed, pure water is added to the dichloromethane phase containing the dissolved salt, and the mixture is stirred. The supernatant is then removed. This process is repeated five or six times, until the pH of the supernatant reaches a neutral range (pH 6-7). After the pH of the supernatant reaches a neutral range, the dichloromethane phase is heated overnight at 60°C in the air, evaporating the dichloromethane and yielding the desired salt.

[0043] Step 3 is a step of preparing a modification solution by dissolving the salt 30 represented by any one of the above general formulas (1) to (4) in a polar solvent. Specifically, the washed and dried salt 30 is dissolved in a polar solvent. The polar solvent is not particularly limited as long as it dissolves the salt of the 1,3,5-triazine derivative cation and the perfluoroalkylsulfonylimide anion. Examples of the polar solvent include alcohols such as ethanol, n-propanol, and 2-propanol, and ketones such as acetone and methyl ethyl ketone. The concentration of the salt dissolved in the modification solution is not particularly limited.

[0044] Step 4 is a step in which the modifying solution prepared in step 3 is brought into contact with a platinum-based catalyst, and then the polar solvent is distilled off to modify the salt 30 into a platinum-based catalyst. The platinum catalyst is not particularly limited in shape as long as it contains platinum or platinum and a metal other than platinum, but a particulate catalyst is preferred. As a catalyst containing platinum and a metal other than platinum, a platinum core-shell catalyst or a platinum alloy catalyst is preferred, as described above. Methods for contacting the platinum-based catalyst with the modifying solution include immersing the platinum-based catalyst in the modifying solution, applying the modifying solution to the platinum-based catalyst, and spraying the modifying solution onto the platinum-based catalyst. A method of immersing a platinum-based catalyst in a modifying solution and distilling off the polar solvent involves, for example, adding a predetermined weight of platinum catalyst or a platinum catalyst supported on a porous carbon material and salt to a predetermined volume of polar solvent, subjecting the mixture to ultrasonic dispersion for 10 to 30 minutes, and then placing the mixture in an evaporator and distilling off the polar solvent under reduced pressure, thereby impregnating and modifying the platinum-based catalyst with the salt. The time required to distill off the polar solvent under reduced pressure using an evaporator is not particularly limited, as long as the platinum-based catalyst can be impregnated and supported with the salt. For example, the lower limit of the distillation time is 1 hour or more, preferably 3 hours or more. The upper limit of the distillation time is not particularly limited, but is 10 hours or less, preferably 5 hours or less. As a method for applying a modifying solution to a platinum-based catalyst and then evaporating off the polar solvent, for example, the platinum-based catalyst can be modified with a salt by applying the modifying solution to the platinum-based catalyst and then evaporating off the polar solvent by heating or the like. The weight of the salt to be impregnated and supported is preferably 10 to 100% by weight, and more preferably 50% by weight or less, particularly preferably 20% by weight or less, when the entire catalyst is taken as 100% by weight.

[0045] In step 4, an unmodified catalyst support, in which a platinum-based catalyst is supported on a porous carbon material, is brought into contact with the modifying solution, and then the polar solvent is distilled off to modify the salt 30 into a platinum-based catalyst, thereby achieving a method for producing a catalyst support of the present invention using the method for producing a catalyst composition of the present invention. Methods for bringing the unmodified catalyst support into contact with the modifying solution include, as described above, immersing the unmodified catalyst support in the modifying solution, applying the modifying solution to the unmodified catalyst support, and spraying the modifying solution onto the unmodified catalyst support. However, the catalyst support of the present invention is not limited to the above-mentioned production method, and may be produced by producing the catalyst composition of the present invention and then supporting it on a carrier. [Example]

[0046] [Salt Selection] A 200 mL beaker was charged with 100 mL of a pH 1 perchloric acid solution. To this acidic solution, 2.744 mmol of either a melamine or 1,3,5-triazine derivative represented by the following general formulas (13) to (18) was added and the mixture was heated to 80°C while being dispersed. Next, 2.744 mmol of either a lithium metal salt of perfluoroalkylsulfonate or a lithium metal salt of perfluoroalkylsulfonylimide represented by the following general formulas (19) to (23) was added to the acidic solution heated to 80°C (Table 1, Samples 1 to 30). After stirring these samples for 10 minutes, if a solid salt was formed, the salt was filtered off and dispersed in 300 mL of pure water, stirred for 10 minutes, and filtered off. This procedure was repeated five times until the pH of the filtrate reached a neutral range (between pH 6 and 7). The washed salt was dried overnight in an oven at 60°C in the air, and the weight of the resulting salt was measured (see Figure 2). For samples where solid salt was confirmed at 80°C, the yield was calculated from the amount of salt obtained, and the results are summarized in Table 1. The yield here is calculated by dividing the yield of the obtained salt by the formula weight of the salt, which is 2.744 x 10 -3This value is obtained by dividing the value by the number of moles of the 1,3,5-triazine derivative and the lithium metal salt of perfluoroalkylsulfonate or the lithium metal salt of perfluoroalkylsulfonylimide used in the synthesis and multiplying the result by 100%. For samples 1 to 30 in Table 1, if this value is 50% or more, it means that the sample will separate from an acidic aqueous solution at 80°C and will be poorly soluble. 20 mL of pure water was placed in a test tube, and 2.0 mmol of either melamine represented by the following general formula (13) or the following general formula (18) was added. The mixture was then heated to 80°C while stirring. Next, either 2.0 mmol of a perfluoroalkylcarboxylic acid represented by the following general formula (24) and 20 mL of pure water, or 2.0 mmol of a perfluoroalkylcarboxylic acid represented by the following general formula (25) and 30 mL of pure water, was added to the solution heated to 80°C (Table 1, Samples 31 to 34). After stirring these samples for 10 to 30 minutes, if a solid salt was formed, the salt was filtered and washed with 200 mL of boiling water. The washed salt was vacuum-dried overnight in a 60°C oven, and the weight of the resulting salt was measured. For samples in which a solid salt was confirmed at 80°C, the yield was calculated from the amount of salt obtained, and the results are summarized in Table 1. The yield was calculated by dividing the yield of the resulting salt by the formula weight of the salt, which is 2.0 x 10 -3 This is the value obtained by dividing the value by the number of moles of the 1,3,5-triazine derivative and perfluoroalkylcarboxylic acid used in the synthesis and multiplying the result by 100%. For samples 31 to 34 in Table 1, if this value is 50% or more, it means that the sample will separate from an acidic aqueous solution at 80°C and will be poorly soluble.

[0047] [ka] "Butylmelamine" [ka] "Benzoguanamine" [ka] "Imizoid-containing 1,3,5 triazine derivatives" [ka] "Diethylmelamine" [ka] "Diallylmelamine" [ka] "melamine" [ka] "Lithium nonafluorobutanesulfonate" [ka] "Lithium heptadecafluorooctanesulfonate" [ka] "Lithium bis(trifluoromethanesulfonyl)imide" [ka] "Lithium bis(pentafluoroethanesulfonyl)imide" [ka] "Lithium bis(nonafluorobutanesulfonyl)imide" [ka] "Nonafluoropentanoic acid" [ka] "Heptadecafluorononanoic acid"

[0048] [Table 1]

[0049] As shown in Table 1, salts were confirmed in samples 2, 5, 7, 10, 12, 14, 15, 17, 20, 22, 25, 30, 31, 32, and 34. In particular, the salts formed from the 11 combinations of samples 2, 5, 12, 14, 15, 17, 20, 22, 25, 32, and 34 had a yield of 50% or more and were found to be highly insoluble in a strongly acidic environment at a temperature of 80°C and a pH of approximately 1.

[0050] [Examples 1 to 5, Comparative Example 1] [Preparation of platinum core-shell catalyst] In the present invention, a highly active platinum-based catalyst was used in which Pt core-shell catalyst particles were supported on Ketjen Black EC-600JD (KB-600JD) manufactured by Lion, a porous carbon support with mesopores of 2 to 50 nm in diameter. 500 mg of KB-600JD was added to 150 ml of pure water and ultrasonically dispersed for 10 minutes. Pd precursor salt was added to this dispersion to achieve a Pd metal loading rate of 50 wt%, and then the water was removed using an evaporator. The resulting solid was collected and dried overnight in an oven at 60°C in air. The dried solid was placed in an alumina boat, placed in a tubular furnace, and thermally reduced at 400°C for 4 hours under an Ar atmosphere to obtain a Pd / KB-600JD core. 600 mg of the resulting Pd / KB-600JD core was added to a separable flask containing 800 ml of pure water and ultrasonically dispersed for 10 minutes. Nitrogen gas was then bubbled through at 500 ml / min while stirring, and the dispersion was cooled to 5°C using an ice bath. When the dispersion reached 5°C, 30 g of 4 M aqueous sulfuric acid was added, adjusting the pH of the dispersion to 0.85. One monolayer of K2PtCl4, a Pt shell precursor, was then added. After stirring at 5°C for 30 minutes, the dispersion was heated to 70°C using a water bath and stirred at 70°C for 3 hours to synthesize the Pt / Pd / KB-600JD core-shell catalyst. The average particle size of this core-shell catalyst was 5.1 nm.

[0051] [Salt modification] [Example 1] Butylmelamine (the above general formula (13)) and lithium bis(nonafluorobutanesulfonyl)imide (Li +[NFSI] - ) (general formula (23)) and [NFSI] - Salt 1 (general formula (26) below) consisting of an anion was dissolved in acetone to a concentration of 100 μM to prepare acetone solution 1 for salt modification (combination of sample 5 in Table 1). A Pt / Pd / KB-600JD core-shell catalyst (amount of Pt metal applied: 14.1 μg / cm) was applied to a glassy carbon (GC) electrode with a diameter of 6 mm. 2 ) (unmodified catalyst support) was immersed in 30 ml of this salt-modifying acetone solution for 10 minutes while stirring at 300 rpm. The GC electrode was then removed from the salt-modifying acetone solution and washed with acetone for 5 seconds to prepare an electrode catalyst (catalyst support) modified with salt 1 (Example 1). [ka]

[0052] [Example 2] Diallylmelamine (the above general formula (17)) and lithium bis(nonafluorobutanesulfonyl)imide (Li + [NFSI] - ) (general formula (23)) and [NFSI] - Salt 2 (general formula (27) below) consisting of an anion was dissolved in acetone to a concentration of 100 μM to prepare acetone solution 2 for salt modification (combination of sample 25 in Table 1). A Pt / Pd / KB-600JD core-shell catalyst (amount of Pt metal applied: 14.1 μg / cm) was applied to a glassy carbon (GC) electrode with a diameter of 6 mm. 2 ) (unmodified catalyst support) was immersed in 30 ml of this salt-modifying acetone solution for 10 minutes while stirring at 300 rpm. The GC electrode was then removed from the salt-modifying acetone solution and washed with acetone for 5 seconds to prepare an electrode catalyst (catalyst support) modified with salt 2 (Example 2). [ka]

[0053] [Example 3] Diethylmelamine (the above general formula (16)) and lithium bis(nonafluorobutanesulfonyl)imide (Li + [NFSI] - ) (general formula (23)) and [NFSI] - Salt 3 (general formula (28) below) consisting of an anion was dissolved in acetone to a concentration of 100 μM to prepare acetone solution 3 for salt modification (combination of sample 20 in Table 1). A Pt / Pd / KB-600JD core-shell catalyst (coated amount as Pt metal: 14.1 μg / cm) was applied to a glassy carbon (GC) electrode with a diameter of 6 mm. 2 ) (unmodified catalyst support) was immersed in 30 ml of this salt-modifying acetone solution for 10 minutes while stirring at 300 rpm. The GC electrode was then removed from the salt-modifying acetone solution and washed with acetone for 5 seconds to prepare an electrode catalyst (catalyst support) modified with salt 3 (Example 3). [ka]

[0054] [Example 4] Imidazole-containing melamine 1,3,5-triazine derivatives (general formula (15)) and lithium bis(nonafluorobutanesulfonyl)imide (Li + [NFSI] - ) (general formula (23)) and [NFSI] - Salt 4 (general formula (29) below) consisting of an anion was dissolved in acetone to a concentration of 100 μM to prepare acetone solution 4 for salt modification (combination of sample 15 in Table 1). A Pt / Pd / KB-600JD core-shell catalyst (coated amount as Pt metal: 14.1 μg / cm) was applied to a glassy carbon (GC) electrode with a diameter of 6 mm. 2) (unmodified catalyst support) was immersed in 30 ml of this salt-modifying acetone solution for 10 minutes while stirring at 300 rpm. The GC electrode was then removed from the salt-modifying acetone solution and washed with acetone for 5 seconds to prepare an electrode catalyst (catalyst support) modified with salt 4 (Example 4). [ka]

[0055] [Example 5] A salt 5 (general formula (30) below) consisting of a diethylmelamine cation and a heptadecafluorooctanesulfonate anion, synthesized using diethylmelamine (general formula (16) above) and lithium heptadecafluorooctanesulfonate (general formula (20) above), was dissolved in acetone to a concentration of 100 μM to prepare an acetone solution 5 for salt modification (combination of sample 17 in Table 1). A Pt / Pd / KB-600JD core-shell catalyst (coated amount of Pt metal: 14.1 μg / cm) was applied to a 6 mm diameter glassy carbon (GC) electrode. 2 ) (unmodified catalyst support) was immersed in 30 ml of this salt-modifying acetone solution for 10 minutes while stirring at 300 rpm. The GC electrode was then removed from the salt-modifying acetone solution and washed with acetone for 5 seconds to prepare an electrode catalyst (catalyst support) modified with salt 5 (Example 5). [ka]

[0056] [Comparative Example 1] Melamine (general formula (18) above) was dissolved in a perchloric acid solution to a concentration of 100 μM (a 1 M perchloric acid solution was used because melamine is insoluble in acetone), and a perchloric acid solution 6 for salt modification was prepared. A Pt / Pd / KB-600JD core-shell catalyst (amount of Pt metal applied: 14.1 μg / cm) was applied to a 6 mm diameter glassy carbon (GC) electrode. 2) (unmodified catalyst support) was immersed in 30 ml of this modifying perchloric acid aqueous solution for 10 minutes while stirring at 300 rpm. Thereafter, the GC electrode was removed from the modifying perchloric acid aqueous solution and washed with pure water for 5 seconds to prepare an electrode catalyst (catalyst support) modified with melamine cations and perchlorate anions (Comparative Example 1).

[0057] "CV measurement and LSV measurement" The GC electrodes (unmodified catalyst carriers) before modification with the salts or melamine of Examples 1 to 5 and Comparative Example 1 were immersed in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 25°C. Cyclic voltammetry (CV) was measured using a three-electrode cell with a platinum wire as the counter electrode and a reversible hydrogen electrode (RHE) as the reference electrode. The potential range during CV measurement was 0.05 V to 1.2 V vs. RHE, and the potential sweep rate was 50 mV / s. To clean the catalyst surface before CV measurement, 70 potential sweeps were repeated with a potential range of 0.05 V to 1.2 V vs. RHE and a potential sweep rate of 100 mV / s. Next, oxygen gas was bubbled through the 0.1 M aqueous perchloric acid solution for 30 minutes to achieve oxygen saturation, and linear sweep voltammetry (LSV) was measured. The potential range during LSV measurement was 0.05 V to 1.2 V vs. RHE, the potential sweep rate was 10 mV / sec, and the rotation speed of the GC electrode was 1600 rpm, sweeping in the positive direction to measure LSV. After completing the electrochemical measurements (CV and LSV) of the unmodified catalyst support, CV and LSV measurements were performed in the same manner on the GC electrodes (catalyst supports) modified with the salts or melamine of Examples 1 to 5 and Comparative Example 1. After electrochemical measurements (CV and LSV) of the catalyst carrier were completed for the GC electrodes of Examples 1 to 5 and Comparative Example 1, each electrode was immersed for 1 hour in a 0.1 M aqueous solution of perchloric acid saturated with argon gas at a temperature of 80° C. Thereafter, the GC electrodes were washed with pure water, and each electrode was again immersed in a 0.1 M aqueous solution of perchloric acid at 25° C., and the CV and LSV were measured under the same conditions. The CV results for Examples 1 to 5 and Comparative Example 1 are shown in Figures 3 to 8(a), and the LSV results are shown in Figures 3 to 8(b). In each figure, "Before modification" represents the CV and LSV of the unmodified catalyst supports of Examples 1 to 5 and Comparative Example 1 before the Pt / Pd / KB-600JD core-shell catalyst was modified with melamine. "After modification" represents the CV and LSV of the catalyst supports of Examples 1 to 5 in which the Pt / Pd / KB-600JD core-shell catalyst was modified with melamine. "80°C, 1 hour" represents the CV and LSV of the salts of Examples 1 to 5 and the catalyst support of Comparative Example 1 after immersion in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C for 1 hour.

[0058] "CV result" In the CV of the melamine-modified GC electrode (catalyst carrier) of Comparative Example 1 (Figure 8(a)), the platinum oxidation current observed at 0.7 V to 1.0 V vs. RHE was reduced compared to the unmodified catalyst carrier, indicating that platinum oxidation was suppressed by the melamine modification. However, when immersed in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80 °C for 1 hour, a platinum oxidation current was observed at 0.7 V to 1.0 V vs. RHE similar to that of the GC electrode (unmodified catalyst carrier) before melamine modification. This is thought to be due to the melamine that modified the Pt core-shell catalyst being dissolved and desorbed into the 0.1 M aqueous perchloric acid solution at 80 °C or into the catalyst layer. In Examples 1 to 5 (FIGS. 3 to 7(a)), when the sample was immersed for one hour in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C, the platinum oxidation current at a potential of 0.7 V to 1.0 V vs. RHE increased compared to after modification, but the degree of increase was smaller than in the case of melamine. Therefore, based on the CV change at 0.7 V to 1.0 V vs. RHE, it is believed that in Examples 1 to 5, platinum oxidation was suppressed compared to the melamine in Comparative Example 1, even after one hour of immersion in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C.

[0059] "LSV result" The LSV (Figure 8(b)) of the GC electrode (catalyst support) after melamine modification in Comparative Example 1 shifted to a higher potential side compared to the GC electrode (unmodified catalyst support) before melamine modification, indicating improved ORR activity of the Pt core-shell catalyst. On the other hand, when the electrode was immersed in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C for 1 hour, the LSV shifted to a lower potential side compared to the pre-modification side, indicating a decrease in ORR activity. This is thought to be due to the dissolution and desorption of melamine into the perchloric acid solution or catalyst layer at 80°C, as seen from the change in CV (Figure 8(a)) described above. The LSVs (after modification in Figures 3 to 7(b)) of the GC electrodes (catalyst carriers) modified with the salts of Examples 1 to 5 were shifted to a higher potential side compared to the unmodified GC electrodes. This indicates that modification with the salts of Examples 1 to 5 improved the ORR activity of the Pt core-shell catalysts. Furthermore, when the Pt core-shell catalysts modified with the salts of Examples 1 to 5 were immersed in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C for 1 hour, the LSVs shifted to a lower potential side (80°C, 1 hour in Figures 3 to 7(b)), similar to Comparative Example 1, and the ORR activity decreased. Therefore, it is believed that some of the salts of Examples 1 to 5 were dissolved and desorbed in the 0.1 M aqueous perchloric acid solution at 80°C or in the catalyst layer. As shown in the CV of Figure 8(a), when the melamine-modified GC electrode of Comparative Example 1 was immersed in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80 °C for 1 hour, the platinum oxidation current at 0.7 V to 1.0 V vs. RHE increased to nearly the oxidation current before modification, indicating that melamine was dissolved and desorbed. However, melamine had the greatest effect on highly activating the Pt-based catalyst (see Table 2). When immersed in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80 °C for 1 hour, most of the melamine was dissolved and desorbed. However, due to the significant high-activation effect of melamine, the ORR activity did not decrease significantly compared to Examples 1 to 5 due to the small amount of remaining melamine.

[0060] In the CVs of Examples 1 to 5 and Comparative Example 1, the quantity of electricity was calculated by integrating the platinum oxidation current observed at 0.5 V to 1.0 V vs. RHE. The quantity of electricity after modification was defined as "S1," and the quantity of electricity after immersion for 1 hour in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C was defined as "S2," and the residual rate R of salt or melamine was defined by the following (Equation 3). R=1-(S2-S1) / S1 (Formula 3) As shown in Figure 9(a), the platinum oxidation current observed at 0.5 V to 1.0 V vs. RHE for each CV in Figures 3 to 8 was integrated after modification and after immersion for 1 hour in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80°C, and the electrical quantity after modification, "S1," and the electrical quantity after the high-temperature durability test, "S2," were calculated. 9(b) shows the results of calculating the residual ratio R of the salt using the above formula 3. The residual ratio of melamine in Comparative Example 1 was 0.662, while the residual ratios of the salts in Examples 1 to 5 were 0.755 to 0.800. This shows that modifying the catalyst with a salt comprising a triazine derivative cation according to the present invention and a perfluoroalkylsulfonylimide anion or a perfluoroalkylsulfonate anion increases the residual ratio in 0.1 M perchloric acid at 80°C.

[0061] Table 2 shows the yields (see Table 1) described in "Selection of Salt" for Examples 1 to 5 and Comparative Example 1, the residual ratios of the modified products calculated by the following formula (3), and the ORR mass activities before and after modification and after immersion for 1 hour in a 0.1 M aqueous solution of perchloric acid saturated with argon gas at 80°C. The ORR mass activity was calculated using the diffusion-limited current I at 0.4 V vs. RHE for each LSV. L The ORR current I at 0.9V vs. RHE was calculated, and the activation dominant current I was calculated from the following equation (4). k Calculate this I k The Pt weight on the GC electrode (14.1 μg / cm 2 The ORR mass activity at 0.9 V vs. RHE was calculated by dividing the calculated value by the formula (1). I k =I×I L / (II L )) (Formula 4) The yield of melamine in Comparative Example 1 was 0, and it was soluble in a perchloric acid solution at 80°C and pH 1. On the other hand, the yield of the salts in Examples 1 to 5 was 60% or more, and they were poorly soluble in a perchloric acid solution at 80°C and pH 1. Therefore, the residual rates of the salts in Examples 1 to 5 were higher than that of the melamine in Comparative Example 1. The ORR mass activities of the Pt core-shell catalysts modified with the salts of Examples 1 to 5 were all improved compared to the ORR mass activity before modification. Therefore, it was found that modifying a catalyst with a salt of a triazine derivative cation and a perfluoroalkylsulfonate anion or a salt of a triazine derivative cation and a perfluoroalkylsulfonylimide anion according to the present invention increases the ORR mass activity of the Pt core-shell catalyst. Furthermore, even after immersion of the catalysts modified with the salts of Examples 1 to 5 in a 0.1 M perchloric acid solution (@J) at 80°C for 1 hour, their ORR mass activities remained higher than those of the unmodified catalyst. Therefore, it is believed that a Pt-based catalyst modified with a salt of a triazine derivative cation and a perfluoroalkylsulfonate anion or a salt of a triazine derivative cation and a perfluoroalkylsulfonylimide anion according to the present invention can maintain high ORR activity for a long period of time in the high-temperature (approximately 80°C) and strongly acidic pH (approximately 1) environment of a PEFC cathode.

[0062] [Table 2] *Melamine is colorless and transparent in 0.1M perchloric acid at 80°C and does not produce any sparingly soluble salts, so the yield is 0.

[0063] "Catalyst durability" In Pt core-shell catalysts and Pt alloy catalysts, the high ORR activity is due to the strain effect and electronic effect of non-dispersed metals such as Pd and Co present in the layer below the surface Pt layer. In PEFC cathodes, the potential fluctuates between 0.6 V and 1.0 V vs. RHE due to acceleration and deceleration. The CVs shown in Figures 3(a) to 7(a) indicate that the Pt surface layer is oxidized and reduced within this potential range. This oxidation and reduction causes Ostwald ripening and migration and aggregation of catalyst particles, increasing catalyst particle size and reducing surface area, resulting in a decrease in the ORR mass activity of Pt-based catalysts. Furthermore, this oxidation and reduction also causes the oxidation and leaching of non-Pt metals such as Pd and Co present in the layer below the surface Pt layer, reducing the ORR mass activity. 3(a) to 7(a) show that in the Pt core-shell catalyst modified with a salt of a triazine derivative cation and a perfluoroalkylsulfonate anion according to the present invention, or a salt of a triazine derivative cation and a perfluoroalkylsulfonylimide anion, oxidation of the platinum surface is suppressed at 0.7 V to 1.0 V vs. RHE. Therefore, by modifying a Pt-based catalyst with a salt of a triazine derivative cation and a perfluoroalkylsulfonate anion according to the present invention, or a salt of a triazine derivative cation and a perfluoroalkylsulfonylimide anion, oxidation and elution of non-Pt metals such as Pd and Co can be suppressed, and improved durability can also be expected.

[0064] Salt 3 (general formula 28) consisting of diethylmelamine cation and bis(nonafluorobutanesulfonyl)imide anion, obtained in Example 3, was dissolved in acetone to prepare a modification solution. This solution was applied to a Pt / Pd / KB-600JD core-shell catalyst coated on a GC electrode at a concentration of 10 wt% relative to the catalyst weight, modifying the Pt / Pd / KB-600JD core-shell catalyst with Salt 3. Accelerated durability tests (ADTs) were performed using this GC electrode. ADT consisted of 10,000 square-wave potential cycles from 0.6 V (3 s) to 1.0 V (3 s) vs. RHE in a 0.1 M aqueous perchloric acid solution saturated with argon gas at 80 °C. For comparison, ADT was also performed on a Pt / Pd / KB-600JD core-shell catalyst not modified with Salt 3. The Pt and Pd compositions of the catalysts before and after ADT were analyzed by TEM-EDX, and the oxidation elution rate of the Pd core was calculated from the change in composition before and after ADT (calculated assuming that Pt was not oxidized and eluted). Table 3 shows the Pt and Pd composition and the oxidation and elution rate of the Pd core of the Pt / Pd / KB-600JD core-shell catalyst before and after ADT. For the unmodified catalyst, ADT oxidized and eluted 64% of the Pd core. On the other hand, for the catalyst modified with 10 wt% salt 3, the oxidation and elution rate of the Pd core was 44%. The modification with salt 3 reduced the oxidation and elution rate of the Pd core by 20 percentage points, demonstrating that modification with salt 3 improved the durability of the Pt / Pd / KB-600JD core-shell catalyst. This is because modification with a salt composed of a triazine derivative cation and a perfluoroalkylsulfonate anion, or a salt composed of a triazine derivative cation and a perfluoroalkylsulfonylimide anion, according to the present invention, suppressed oxidation of the platinum surface in the potential range of 0.7 V to 1.0 V vs. RHE.

[0065] [Table 3]

[0066] These results suggest that modifying a Pt-based catalyst with a salt of a triazine derivative cation and a perfluoroalkylsulfonate anion or a salt of a triazine derivative cation and a perfluoroalkylsulfonylimide anion according to the present invention can maintain high ORR mass activity for a long period of time while also improving the durability of the Pt-based catalyst. [Explanation of symbols]

[0067] 1. Fuel cell cathode catalyst 10. Porous carbon support 20 Platinum catalyst particles 30 salt Ionomer

Claims

1. A catalyst composition comprising a platinum-based catalyst and a salt modified with the platinum-based catalyst, wherein the salt comprises a 1,3,5-triazine derivative cation represented by the following general formula (1) and a perfluoroalkylsulfonylimide anion: Catalyst composition. (In the formula, R １ , R ２ , R ３ Rf represents the same or different substituted or unsubstituted amino group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, or other basic functional group. １ , Rf ２ represent the same or different perfluoroalkyl groups.)

2. The salt represented by the general formula (1) is poorly soluble in water, in that when 2.74 mmol of the salt is added to 100 ml of a perchloric acid aqueous solution having a pH of 1 or 100 ml of a nitric acid aqueous solution having a pH of 1 and the temperature of these acidic aqueous solutions is raised to 80°C, 50% or more of the salt added is separated from the acidic aqueous solution. The catalyst composition of claim 1.

3. A catalyst composition comprising a platinum-based catalyst and a salt modified by the platinum-based catalyst, wherein the salt is a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the following general formula (2) and a perfluoroalkylsulfonylimide anion: Catalyst composition. (In the formula, R ４ Rf represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or any other basic functional group. １ , Rf ２ represent the same or different perfluoroalkyl groups.)

4. The salt represented by the general formula (2) is poorly soluble in water, in that when 2.74 mmol of the salt is added to 100 ml of a perchloric acid aqueous solution having a pH of 1 or 100 ml of a nitric acid aqueous solution having a pH of 1 and the temperature of these acidic aqueous solutions is raised to 80°C, 50% or more of the salt added is separated from the acidic aqueous solution. The catalyst composition of claim 3.

5. The Rf １ and / or Rf ２ The perfluoroalkyl has 4 or more carbon atoms.

5. The catalyst composition according to claim 1.

6. A catalyst composition comprising a platinum-based catalyst and a salt modified by the platinum-based catalyst, wherein the salt is a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the following general formula (3) and a perfluoroalkylsulfonate anion: Catalyst composition. (In the formula, R ４ Rf represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or any other basic functional group. ３ represents perfluoroalkyl.)

7. The salt represented by the general formula (3) is poorly soluble in water, in that when 2.74 mmol of the salt is added to 100 ml of a perchloric acid aqueous solution having a pH of 1 or 100 ml of a nitric acid aqueous solution having a pH of 1 and the temperature of these acidic aqueous solutions is raised to 80°C, 50% or more of the salt added is separated from the acidic aqueous solution. The catalyst composition of claim 6.

8. The Rf ３ The number of carbon atoms of the perfluoroalkyl is greater than 4, The catalyst composition according to claim 6 or 7.

9. A catalyst composition comprising a platinum-based catalyst and a salt modified by the platinum-based catalyst, wherein the salt is a salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the following general formula (4) and a perfluoroalkyl carboxylic acid anion: Catalyst composition. (In the formula, R ４ Rf represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or any other basic functional group. ４ represents perfluoroalkyl.)

10. The salt represented by the general formula (4) is poorly soluble in such a manner that, when 2.0 mmol of the 2,4-diamino-1,3,5-triazine derivative constituting the salt is added to 20 ml of pure water and the mixture is heated to 80°C, and then 2.0 mmol of perfluoroalkylcarboxylic acid and 20 ml or 30 ml of pure water are added, 1.0 mmol or more of the salt is separated from the aqueous solution. The catalyst composition of claim 9.

11. The Rf ４ The number of carbon atoms of the perfluoroalkyl is greater than 4, The catalyst composition according to claim 9 or 10.

12. The platinum-based catalyst is a platinum core-shell catalyst comprising a core particle containing palladium, cobalt, nickel, iron, or copper, and a platinum shell formed on the surface of the core particle.

12. The catalyst composition according to any one of claims 1 to 11.

13. The platinum-based catalyst is a platinum alloy catalyst containing platinum and palladium, cobalt, nickel, iron, or copper.

12. The catalyst composition according to any one of claims 1 to 11.

14. A catalyst support comprising the catalyst composition according to any one of claims 1 to 13 supported on a porous carbon material.

15. A cathode electrode for a fuel cell, comprising the catalyst composition according to any one of claims 1 to 13 or the catalyst support according to claim 14.

16. A fuel cell comprising an anode electrode for a fuel cell and the cathode electrode for a fuel cell according to claim 15.

17. a modifying solution obtained by dissolving any one of a salt of a 1,3,5-triazine derivative cation represented by the general formula (1) and a perfluoroalkylsulfonylimide anion, a salt of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (2) and a perfluoroalkylsulfonylimide anion, a salt of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (3) and a perfluoroalkylsulfonate anion, or a salt of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (4) and a perfluoroalkylcarboxylate anion in a polar solvent, the solution being brought into contact with a platinum-based catalyst, and the polar solvent being distilled off to modify the platinum-based catalyst with the salt; A method for producing a catalyst composition. (In general formulas (1) to (4), R １ , R ２ , R ３ , R ４ Rf represents the same or different substituted or unsubstituted amino group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, or other basic functional group. １ , Rf ２ , Rf ３ , Rf ４ represent the same or different perfluoroalkyl groups.)

18. A salt consisting of a 1,3,5-triazine derivative cation represented by the general formula (1) and a perfluoroalkylsulfonylimide anion is produced by adding a 1,3,5-triazine derivative represented by the general formula (5) and a perfluoroalkylsulfonylimide metal salt represented by the general formula (6) to an acidic aqueous solution having a temperature of 60°C or higher and a pH of 3 or lower. A method for producing the catalyst composition of claim 17. (In general formulas (5) and (6), R １ , R ２ , R ３ Rf represents the same or different substituted or unsubstituted amino groups, substituted or unsubstituted aryl groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, or other basic functional groups; １ , Rf ２ represent the same or different perfluoroalkyl groups, and X represents a metal atom.

19. A salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (2) and a perfluoroalkylsulfonylimide anion is produced by adding a 2,4-diamino-1,3,5-triazine derivative represented by the general formula (7) and a perfluoroalkylsulfonylimide metal salt represented by the general formula (8) to an acidic aqueous solution having a temperature of 60°C or higher and a pH of 3 or lower. A method for producing the catalyst composition of claim 17. (In general formulas (7) and (8), R ４ represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or any other basic functional group; Rf １ , Rf ２ represent the same or different perfluoroalkyl groups, and X represents a metal atom.

20. A salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (3) and a perfluoroalkylsulfonic acid anion is produced by adding a 2,4-diamino-1,3,5-triazine derivative represented by the general formula (9) and a perfluoroalkylsulfonic acid metal salt represented by the general formula (10) to an acidic aqueous solution having a temperature of 60°C or higher and a pH of 3 or lower. A method for producing the catalyst composition of claim 17. (In general formulas (9) and (10), R ４ represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or any other basic functional group; Rf ３ represents a perfluoroalkyl group, and X represents a metal atom.

21. A salt consisting of a 2,4-diamino-1,3,5-triazine derivative cation represented by the general formula (4) and a perfluoroalkylcarboxylic acid anion is produced by adding a 2,4-diamino-1,3,5-triazine derivative represented by the general formula (11) to an aqueous solution of 60°C or higher containing a perfluoroalkylcarboxylic acid represented by the general formula (12). A method for producing the catalyst composition of claim 17. (In general formulas (11) and (12), R ４ represents a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or any other basic functional group; Rf ４ represents a perfluoroalkyl group, and X represents a metal atom.

22. A method for producing a catalyst support using the method for producing a catalyst composition according to any one of claims 17 to 21, bringing the modifying solution into contact with an unmodified catalyst support in which the platinum-based catalyst is supported on a support made of a porous carbon material; A method for producing a catalyst support.

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