Metal-supported catalysts, electrodes and batteries

Abstract

To provide a metal-loaded catalyst that, while having a large noble metal content, exhibits both an excellent durability and an excellent catalytic function and also provide an electrode and a battery.SOLUTION: A metal-loaded catalyst comprises a carbon support and noble metal alloy-containing catalyst metal particles supported by the carbon support. The percentage for the weight of the noble metal with reference to the weight of the metal-loaded catalyst is at least 35 wt.%, and the BET specific surface area is at least 350 (m2 / g-carbon support). The metal-loaded catalyst has the following property (a1) and / or property (a2): (a1) in the Raman spectrum provided by Raman spectroscopy, the ratio of the intensity of the 2D band having a peak top in the vicinity of a Raman shift of 2680 cm-1 to the intensity of the G band having a peak top in the vicinity of a Raman shift of 1600 cm-1, is at least 0.20 and at most 1.00; (a2) in the Raman spectrum provided by Raman spectroscopy, the half width at half maximum of the D band having a peak top in the vicinity of a Raman shift of 1340 cm-1 is at most 41.0 cm-1. The metal-loaded catalyst also has the following property (b1) and / or property (b2): (b1) the alloy composition heterogeneity is at most 0.55; (b2) the half-maximum asymmetry and the 1 / 4-maximum asymmetry are both at most 0.55.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a supported metal catalyst, an electrode, and a battery. [Background technology]

[0002] Patent Document 1 describes a catalyst for an air electrode of a polymer solid electrolyte fuel cell, in which catalyst particles made of an alloy of platinum and one auxiliary metal are supported on a carbon powder support, the auxiliary metal being iron or cobalt, and the compounding ratio of platinum to the auxiliary metal being 6:1 to 3:2 (molar ratio).

[0003] Patent Document 2 describes an electrode catalyst for a fuel cell, which contains a solid carbon support and an alloy of platinum and cobalt supported on the support.

[0004] Patent Document 3 describes an electrode catalyst in which a catalytic metal is supported on a catalyst carrier, the catalytic metal containing platinum and metal components other than platinum, having mesopores with a radius of 1 nm or more, the mode radius of the mesopore distribution being 1 nm or more and less than 2.5 nm, alloy fine particles of platinum and metal components other than platinum supported in the mesopores, and the molar ratio of platinum to metal components other than platinum in the alloy fine particles supported in the mesopores being 1.0 to 10.0.

[0005] Patent Document 4 describes an electrode catalyst in which catalytic components including alloy fine particles made of platinum and metal components other than platinum are supported on a catalyst support, wherein the catalyst support has mesopores with a radius of 1 nm or more, the mode radius of the pore distribution of the mesopores is 1 nm or more and less than 2.5 nm, at least a portion of the alloy fine particles are supported within the mesopores, and the measured lattice constant Q [Å] of the alloy fine particles is smaller than the theoretical lattice constant P [Å] according to Vegard's law, which is calculated using the following formula: theoretical lattice constant P [Å] = (lattice constant of platinum - lattice constant of non-platinum metal atoms) × mole fraction of platinum atoms in the alloy fine particles + lattice constant of non-platinum metal atoms.

[0006] Patent Document 5 describes a method for producing an alloy catalyst, which includes a first step of mixing a precious metal compound containing a precious metal element, a base metal compound containing a base metal element, a first solvent, and a porous material to obtain a mixture; a second step of removing the first solvent from the mixture until the following formula is satisfied: (volume of the first solvent in the mixture)≦(pore volume of the porous material)×5, thereby fixing the precious metal compound and the base metal compound to the porous material; and a third step of contacting the porous material with a reducing solution containing a reducing agent having an oxidation-reduction potential of −1.20 V or less and a second solvent, wherein the amount of the reducing agent in the reducing solution is 5 times or more the total amount of the precious metal elements. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-142112 [Patent Document 2] International Publication No. 2016 / 063968 [Patent Document 3] International Publication No. 2017 / 183475 [Patent Document 4] Japanese Patent Application Publication No. 2018-116815 [Patent Document 5] Japanese Patent Publication No. 2020-171917 Summary of the Invention [Problem to be solved by the invention]

[0008] However, it has been difficult to realize a metal-supported catalyst that has a high noble metal content and yet has both excellent durability and excellent catalytic function.

[0009] The present invention has been made in view of the above-mentioned problems, and one of its objects is to provide a metal-supported catalyst, an electrode, and a battery that have a high precious metal content and yet have both excellent durability and excellent catalytic function. [Means for solving the problem]

[0010] A metal-supported catalyst according to one embodiment of the present invention for solving the above-mentioned problems is a metal-supported catalyst comprising a carbon support and catalytic metal particles containing a precious metal alloy supported on the carbon support, wherein the ratio of the weight of the precious metal to the weight of the metal-supported catalyst is 35% by weight or more, and the BET specific surface area is 350 (m 2 / g-carbon support) or more and has the following characteristics (a1) and / or (a2): (a1) In the Raman spectrum obtained by Raman spectroscopy, the Raman shift is 1600 cm -1 Raman shift of the G band intensity with a peak top near 2680 cm -1 The ratio of the intensities of 2D bands with peak tops nearby is 0.20 or more and 1.00 or less; (a2) In the Raman spectrum obtained by Raman spectroscopy, the Raman shift is 1340 cm -1 The half-width at half maximum of the D band with a peak top near -1 below; and, The following characteristics (b1) and / or (b2): (b1) the alloy composition non-uniformity calculated by the following formula (I) is 0.55 or less; JPEG0007720272000001.jpg12170 (In the above formula (I), the theoretical lattice constant and the measured lattice constant are the theoretical lattice constant and the measured lattice constant of the noble metal alloy, respectively.) (b2) the half-value asymmetry and quarter-value asymmetry calculated by the following formula (II) and formula (III), respectively, are both 0.55 or less; JPEG0007720272000002.jpg11170JPEG0007720272000003.jpg14170 (In the above formula (II) and formula (III), D m is the value of the diffraction angle 2θ at which the diffraction line shows maximum intensity within the range of diffraction angle 2θ in which the diffraction peak of the (111) plane of the precious metal alloy appears in the X-ray diffraction pattern obtained by powder X-ray diffraction, and D Lhis the smallest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line exhibits half the maximum intensity in the above range, and D Hh is the largest value of the diffraction angle 2θ among the diffraction angles 2θ at which the diffraction line shows half the maximum intensity in the above range, and D Lq is the smallest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line exhibits an intensity that is one-fourth of the maximum intensity in the above range, and D Hq is the largest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows an intensity of one-fourth of the maximum intensity within the above range.) According to the present invention, there is provided a metal-supported catalyst that has a large noble metal content and yet combines excellent durability and excellent catalytic function.

[0011] The metal-supported catalyst may have the characteristic (a1). The metal-supported catalyst may have the characteristic (a2). The metal-supported catalyst may have the characteristic (b1). The metal-supported catalyst may have the characteristic (b2).

[0012] The metal-supported catalyst may have an average pore size of 8.0 nm or less, and a molar ratio of noble metal to non-noble metal of 1.0 or more.

[0013] The metal-supported catalyst may have a number-average particle size of the catalytic metal particles of 8.0 nm or less, and a volume-average particle size of the catalytic metal particles of 8.0 nm or less.

[0014] The metal-supported catalyst may have a sweep rate dependency of the electrochemically effective specific surface area (ECSA) of the noble metal contained in the metal-supported catalyst, calculated by the following formula (IV), of 60% or more. JPEG0007720272000004.jpg19170 (In the above formula (IV), "ECSA@1000mV" and "ECSA@10mV" are the electrochemically effective specific surface areas (m) per gram of the noble metal contained in the metal-supported catalyst, which are obtained by cyclic voltammetry using a rotating ring-disk electrode apparatus having a working electrode on which the metal-supported catalyst is supported, with a potential sweep at a sweep rate of 1000mV / sec and a potential sweep at a sweep rate of 10mV / sec, respectively. 2 / g-precious metals).

[0015] According to one embodiment of the present invention, there is provided an electrode having excellent properties, which comprises any one of the above-described metal-supported catalysts.

[0016] According to one embodiment of the present invention, a battery having excellent characteristics is provided, the battery including the electrode. [Effects of the Invention]

[0017] According to the present invention, there are provided a metal-supported catalyst, an electrode, and a battery that have a high noble metal content and yet have both excellent durability and excellent catalytic function. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram showing an example of the results of analyzing a Raman spectrum obtained by Raman spectroscopy of a metal-supported catalyst in an example according to the present embodiment. [Figure 2] FIG. 1 is an explanatory diagram showing a typical X-ray diffraction pattern obtained by powder X-ray diffraction of a metal-supported catalyst. [Figure 3A] FIG. 2 is an explanatory diagram showing an example of the results of analyzing an X-ray diffraction pattern obtained by powder X-ray diffraction of a metal-supported catalyst in an example according to the present embodiment. [Figure 3B] FIG. 10 is an explanatory diagram showing another example of the results of analyzing the X-ray diffraction pattern obtained by powder X-ray diffraction of the metal-supported catalyst in the example according to the present embodiment. [Figure 4A] FIG. 2 is an explanatory diagram showing an example of the results of analyzing an X-ray diffraction pattern obtained by powder X-ray diffraction of a metal-supported catalyst in an example according to the present embodiment. [Figure 4B] FIG. 10 is an explanatory diagram showing another example of the results of analyzing the X-ray diffraction pattern obtained by powder X-ray diffraction of the metal-supported catalyst in the example according to the present embodiment. [Figure 5A] FIG. 2 is an explanatory diagram showing an example of the results of analyzing an X-ray diffraction pattern obtained by powder X-ray diffraction of a metal-supported catalyst in an example according to the present embodiment. [Figure 5B] FIG. 10 is an explanatory diagram showing another example of the results of analyzing the X-ray diffraction pattern obtained by powder X-ray diffraction of the metal-supported catalyst in the example according to the present embodiment. [Figure 5C] FIG. 10 is an explanatory diagram showing yet another example of the results of analyzing the X-ray diffraction pattern obtained by powder X-ray diffraction of the metal-supported catalyst in the example according to the present embodiment. [Figure 5D] FIG. 5D is an explanatory diagram showing an enlarged portion of the X-ray diffraction pattern shown in FIG. 5C. [Figure 6A] FIG. 10 is an explanatory diagram showing yet another example of the results of analyzing the X-ray diffraction pattern obtained by powder X-ray diffraction of the metal-supported catalyst in the example according to the present embodiment. [Figure 6B] FIG. 6B is an explanatory diagram showing an enlarged portion of the X-ray diffraction pattern shown in FIG. 6A. [Figure 7] FIG. 1 is an explanatory diagram showing an example of the results of evaluating the ECSA sweep rate dependency of a metal-supported catalyst in an example according to this embodiment. [Figure 8A] FIG. 2 is an explanatory diagram showing an equivalent circuit. [Figure 8B] FIG. 1 is an explanatory diagram showing actual measurement values and fitting results of a Nyquist plot obtained for a metal-supported catalyst in an example according to the present embodiment. [Figure 9A] FIG. 1 is an explanatory diagram showing the manufacturing conditions of a metal-supported catalyst in an example according to the present embodiment, and the results of evaluating the characteristics of a fuel cell including the metal-supported catalyst. [Figure 9B]FIG. 1 is an explanatory diagram showing the results of evaluating the characteristics of a metal-supported catalyst in an example according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the present invention will be described below, but the present invention is not limited to the example shown in this embodiment.

[0020] The metal-supported catalyst according to this embodiment (hereinafter referred to as "the catalyst") includes a carbon support and catalytic metal particles, which include a noble metal alloy, supported on the carbon support.

[0021] The carbon support contained in the catalyst is a carbon material mainly composed of carbon. The carbon content of the carbon support may be, for example, 70% by weight or more, preferably 75% by weight or more, more preferably 80% by weight or more, and particularly preferably 85% by weight or more.

[0022] The carbon content of the carbon support may be, for example, 100% by weight or less, 95% by weight or less, or 90% by weight or less. The carbon content of the carbon support may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The carbon content of the carbon support is obtained by elemental analysis (combustion method).

[0023] The carbon support is preferably a carbonized material. The carbonized material is obtained by carbonizing a raw material containing organic matter. The content of the organic matter in the raw material for carbonization may be, for example, 5% by weight or more and 90% by weight or less, and preferably 10% by weight or more and 80% by weight or less.

[0024] The organic matter contained in the raw material is not particularly limited as long as it can be carbonized. The organic compounds may be polymers (e.g., thermosets and / or thermoplastics). and / or may be organic compounds with lower molecular weights.

[0025] The carbon support preferably contains nitrogen. That is, the carbon support preferably contains a nitrogen atom in its carbon structure. The nitrogen-containing carbon support is preferably a nitrogen-containing carbonized material. The nitrogen-containing carbonized material is obtained, for example, by carbonizing a raw material containing a nitrogen-containing organic substance. The nitrogen-containing organic substance preferably contains a nitrogen-containing organic compound. The nitrogen-containing organic compound is not particularly limited as long as it is an organic compound containing a nitrogen atom in its molecule. Furthermore, the nitrogen contained in the carbon support may be introduced by nitrogen doping treatment.

[0026] The nitrogen content of the carbon support may be, for example, 0.10 wt% or more, preferably 0.15 wt% or more, more preferably 0.20 wt% or more, even more preferably 0.25 wt% or more, and particularly preferably 0.30 wt% or more. The nitrogen content of the carbon support may be, for example, 10.00 wt% or less. The nitrogen content of the carbon support is obtained by elemental analysis (combustion method) of the carbon support.

[0027] The carbon support is preferably a carbonized material obtained by carbonizing a raw material containing an organic substance and a metal. In this case, the carbon support may be a carbonized material that has been subjected to a metal removal treatment after carbonization. The metal removal treatment is a treatment for reducing the amount of metals derived from the raw material contained in the carbonized material. Specifically, the metal removal treatment is preferably, for example, an acid washing treatment and / or an electrolytic treatment.

[0028] When the carbon support is a carbonized material obtained by carbonizing a raw material containing an organic substance and a metal, the carbon support may contain a metal (hereinafter referred to as a "raw material metal") derived from the raw material of the carbonization. In this case, the carbon support contains the raw material metal inside the skeleton that constitutes its porous structure. Even when the carbon support is a carbonized material produced through a metal removal treatment as described above, the raw material metal remains inside the skeleton of the carbon support. Of the raw material metals contained in the carbon support, the weight of the raw material metal contained inside the skeleton of the carbon support may be greater than the weight of the raw material metal contained on the surface of the skeleton of the carbon support.

[0029] The raw material metal inside the skeleton of the carbon support can be detected, for example, by subjecting the skeleton to a surface etching treatment and analyzing the cross section exposed by the etching treatment. That is, in this case, when one particle of the carbon support is subjected to an etching treatment, the raw material metal is detected on the cross section of the particle exposed by the etching treatment. The raw material metal contained in the carbon support can be detected, for example, by inductively coupled plasma atomic emission spectroscopy of the carbon support.

[0030] The raw metal content of the carbon support (the ratio of the weight of the raw metal contained in the carbon support to the weight of the carbon support) may be, for example, 0.001 wt % or more, 0.005 wt % or more, 0.01 wt % or more, or 0.02 wt % or more. The raw metal content of the carbon support may be, for example, 5 wt % or less, 4 wt % or less, 3 wt % or less, 2 wt % or less, 1 wt % or less, 0.8 wt % or less, or 0.5 wt % or less. The raw metal content of the carbon support may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The raw metal content of the carbon support may be obtained, for example, by inductively coupled plasma atomic emission spectroscopy of the carbon support.

[0031] The raw material metal is preferably a transition metal, that is, the raw material metal is preferably a transition metal belonging to Groups 3 to 12 of the periodic table, and particularly preferably a transition metal belonging to the fourth period of Groups 3 to 12 of the periodic table.

[0032] The source metal may be a transition metal other than platinum, or a transition metal other than a noble metal (e.g., ruthenium (Ru), palladium (Pd), rhodium (Rh), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au)).

[0033] Specifically, the raw material metal may be, for example, one or more selected from the group consisting of scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), lanthanides (e.g., gadolinium (Gd)), and actinides, and is preferably one or more selected from the group consisting of Fe, Co, Ni, Cu, and Zn, more preferably one or more selected from the group consisting of Fe, Co, Ni, and Zn, and particularly preferably one or more selected from the group consisting of Co, Ni, and Zn.

[0034] Carbonization in the production of a carbonized material is carried out by heating the raw material at a temperature at which the organic matter contained in the raw material is carbonized. The carbonization temperature is not particularly limited as long as it is a temperature at which the raw material is carbonized, and is, for example, preferably 1200°C or higher, more preferably 1300°C or higher, even more preferably 1400°C or higher, and particularly preferably 1500°C or higher.

[0035] The carbonization temperature may be, for example, 3000°C or lower, preferably 2500°C or lower, and particularly preferably 2000°C or lower. The carbonization temperature may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The rate of temperature rise to the carbonization temperature is not particularly limited, and may be, for example, 0.5°C / min or higher and 300°C / min or lower. Carbonization is preferably carried out in an inert atmosphere such as a nitrogen atmosphere.

[0036] Carbonization may be carried out under normal pressure (atmospheric pressure), but is preferably carried out under pressure (under pressure higher than atmospheric pressure). When carbonization is carried out under pressure, the pressure of the atmosphere in which the carbonization is carried out may be, for example, 0.05 MPa or more in gauge pressure, preferably 0.15 MPa or more in gauge pressure, more preferably 0.20 MPa or more, even more preferably 0.40 MPa or more, and particularly preferably 0.50 MPa or more. The upper limit of the pressure of the atmosphere in which the carbonization is carried out is not particularly limited, but the pressure may be, for example, 10 MPa or less in gauge pressure.

[0037] The carbon support is preferably a carbonized material that has been subjected to a graphitization treatment after carbonization, i.e., the carbon support is preferably a carbonized material obtained by, for example, carbonizing a raw material containing an organic substance and then graphitizing the carbonized material.

[0038] The graphitization treatment is carried out by heating the carbonized material at a temperature at which graphitization proceeds. The heating temperature at which the carbonized material is heated in the graphitization treatment is not particularly limited as long as it is a temperature at which graphitization proceeds in the carbonized material, but is preferably a temperature higher than the carbonization temperature for obtaining the carbonized material.

[0039] Specifically, the heating temperature in the graphitization treatment may be, for example, 1300°C or higher, preferably 1400°C or higher, more preferably 1500°C or higher, even more preferably 1600°C or higher, still more preferably 1700°C or higher, still more preferably 1750°C or higher, and particularly preferably 1800°C or higher.

[0040] The heating temperature in the graphitization treatment may be, for example, 3000°C or lower, preferably 2500°C or lower, more preferably 2400°C or lower, even more preferably 2300°C or lower, still more preferably 2250°C or lower, still more preferably 2200°C or lower, still more preferably 2150°C or lower, and particularly preferably 2100°C or lower. The heating temperature in the graphitization treatment may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The rate of temperature rise up to the heating temperature in the graphitization treatment is not particularly limited and may be, for example, 0.5°C / min or higher and 300°C / min or lower. The graphitization treatment is preferably performed in an inert atmosphere such as a nitrogen atmosphere.

[0041] When the carbon support is a carbonized material that has been subjected to a graphitization treatment after carbonization, it is preferable that the carbonized material after the graphitization treatment is not subjected to a pulverization treatment. That is, in the production of the carbon support, for example, it is preferable that the carbonized material obtained by carbonizing a raw material is subjected to a pulverization treatment to adjust its median diameter, and then the pulverized carbonized material is subjected to a graphitization treatment, but the carbonized material after the graphitization treatment is not subjected to a pulverization treatment.

[0042] The carbon support is preferably a carbon material that exhibits catalytic activity. That is, in this case, the carbon support is a carbon catalyst that exhibits catalytic activity by itself. The carbon support that is a carbon catalyst is preferably a carbonized material obtained by carbonizing a raw material containing an organic substance and a metal, as described above.

[0043] The catalytic activity exhibited by the carbon support is preferably, for example, reduction activity and / or oxidation activity, more preferably oxygen reduction activity and / or hydrogen oxidation activity, and particularly preferably at least oxygen reduction activity.

[0044] In this catalyst, the catalytic metal particles supported on the carbon support contain a precious metal alloy. A precious metal alloy is an alloy of a precious metal and a metal other than a precious metal (hereinafter referred to as a "non-precious metal"). That is, a precious metal alloy contains one or more precious metals and one or more non-precious metals. The catalytic metal particles may further contain a precious metal that is not alloyed (hereinafter sometimes referred to as a "pure precious metal").

[0045] The noble metal is preferably one or more selected from the group consisting of ruthenium (Ru), palladium (Pd), rhodium (Rh), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au), more preferably one or more selected from the group consisting of Ru, Pd, Rh, Ir, and Pt, and particularly preferably Pt.

[0046] That is, the catalytic metal particles preferably contain a platinum alloy. A platinum alloy is an alloy of platinum and a non-precious metal. That is, a platinum alloy contains platinum and one or more non-precious metals. The platinum alloy may further contain one or more other precious metals, or may not contain any other precious metals. The catalytic metal particles may further contain platinum that is not alloyed (hereinafter, sometimes referred to as "pure platinum").

[0047] The non-precious metal constituting the precious metal alloy is not particularly limited as long as it is a metal other than a precious metal that forms an alloy with the precious metal, but is preferably a transition metal other than a precious metal. Specifically, the non-precious metal contained in the precious metal alloy is preferably one or more selected from the group consisting of titanium (Ti), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), niobium (Nb), and cerium (Ce), more preferably one or more selected from the group consisting of Fe, Co, and Ni, and particularly preferably one or more selected from the group consisting of Co and Ni.

[0048] When the carbon support is a carbonized material of a raw material containing an organic substance and a raw material metal, the catalytic metal particles supported on the carbon support may contain the same type of metal as the raw material metal, or may not contain the same type of metal as the raw material metal.

[0049] The catalytic activity of the catalytic metal particles is not particularly limited as long as the effects of the present invention are obtained. However, the catalytic metal particles preferably exhibit, for example, reduction activity and / or oxidation activity, more preferably oxygen reduction activity and / or hydrogen oxidation activity, and particularly preferably at least oxygen reduction activity.

[0050] This catalyst exhibits a Raman shift of 1600 cm in the Raman spectrum obtained by Raman spectroscopy. -1 (specifically, for example, 1550 cm -1 More than 1700cm -1 The Raman shift of the G band with a peak top at 2680 cm -1 around (specifically, for example, 2600 cm -1 More than 2800cm -1 It is preferable that the carbon structure has a ratio of the intensities of 2D bands having peak tops within the range below (hereinafter referred to as "Raman 2D / G ratio") of 0.20 or more and 1.00 or less.

[0051] The Raman 2D / G ratio of the present catalyst is, for example, more preferably 0.25 or more, even more preferably 0.30 or more, even more preferably 0.35 or more, even more preferably 0.40 or more, even more preferably 0.45 or more, even more preferably 0.50 or more, and particularly preferably 0.55 or more.

[0052] Furthermore, the Raman 2D / G ratio of the present catalyst is, for example, preferably 0.95 or less, more preferably 0.90 or less, even more preferably 0.85 or less, even more preferably 0.80 or less, even more preferably 0.75 or less, even more preferably 0.70 or less, even more preferably 0.65 or less, and particularly preferably 0.60 or less. The Raman 2D / G ratio of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0053] Here, the Raman 2D / G ratio of a carbon material indicates the number of layers constituting the graphene stack contained in the carbon structure of the carbon material. That is, when the intensity of the 2D band is greater than the intensity of the G band (Raman 2D / G ratio > 1), the graphene is a single layer. When the intensity of the 2D band is the same as the intensity of the G band (Raman 2D / G ratio = 1), the number of layers of the graphene stack is approximately two. When the intensity of the 2D band is smaller than the intensity of the G band (Raman 2D / G ratio < 1), the number of layers of the graphene stack is three or more. The specific number of layers can be determined from the ratio of the intensity of the 2D band (peak top height) to the intensity of the G band (peak top height).

[0054] A carbon structure that exhibits a too small Raman 2D / G ratio, i.e., a carbon structure with too many graphene stack layers, has poor durability because the relative amount of edge portions, which are the starting point for oxidative degradation, to the basal plane is too large. In contrast, a carbon structure that exhibits a Raman 2D / G ratio equal to or greater than the above-mentioned lower limit contains few-layer graphene in which the number of graphene stack layers is controlled within an appropriate range (e.g., about two to three layers), and the relative amount of exposed edge portions to the basal plane is controlled within an appropriate range, contributing to improved durability.

[0055] On the other hand, the edge portions also function as support sites for catalytic metal particles. Therefore, a carbon structure exhibiting a Raman 2D / G ratio that is too large has too little edge portion relative to the basal plane, making it less suitable for supporting catalytic metal particles. In contrast, a carbon structure exhibiting a Raman 2D / G ratio that is equal to or less than the upper limit described above has an appropriate amount of edge portion relative to the basal plane, making it more suitable for supporting catalytic metal particles, and as a result, contributes to improving the durability and / or catalytic function of the metal-supported catalyst.

[0056] This catalyst exhibited a Raman shift of 1340 cm in the Raman spectrum obtained by Raman spectroscopy. -1 Around (specifically, for example, 1320 cm -1 Above, 1360cm -1 The half width at half maximum of the D band (hereinafter referred to as "Raman D half width at half maximum") having a peak top within the range of 41.0 cm -1 It is preferred to have the carbon structure shown below:

[0057] The Raman D half width at half maximum of this catalyst is, for example, 40.0 cm -1 It is more preferable that it is 38.0 cm or less. -1 More preferably, it is 36.0 cm or less. -1 More preferably, it is 34.0 cm or less. -1 More preferably, it is 32.0 cm or less. -1 More preferably, it is 30.0 cm or less. -1 More preferably, it is 28.0 cm or less. -1 More preferably, it is 27.0 cm or less. -1 More preferably, it is 26.5 cm or less. -1 More preferably, it is 26.0 cm or less. -1 It is particularly preferred that:

[0058] The Raman D half width at half maximum of the catalyst is, for example, 20.0 cm -1 It may be more than 21.0cm -1 It is preferable that it is 22.0 cm or more. -1More preferably, it is 22.5cm or more. -1 More preferably, it is 23.0 cm or more. -1 More preferably, it is 23.5 cm or more. -1 More preferably, it is 24.0 cm or more. -1 More preferably, it is 24.5 cm or more. -1 The Raman D half width at half maximum of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0059] According to a reference (A. Sadezky et al., Carbon 43 (2005) 1731-1742), in the Raman spectrum of a carbon material, the D band is a component derived from carbon atoms close to a disordered lattice, such as the edge portion of a graphene layer. The half-width at half maximum of the D band indicates the crystallinity of the carbon around the edge portion. In other words, the higher the crystallinity of the carbon around the edge portion of a carbon structure, the smaller the Raman D half-width at half maximum of the carbon structure. Therefore, a carbon structure that exhibits a Raman D half-width at half maximum of the above-mentioned upper limit or less contains highly crystalline carbon around the edge portion, which contributes to improved durability.

[0060] On the other hand, a carbon structure exhibiting a Raman D half width at half maximum that is too small has too high a crystallinity of carbon around the edge portion, making it less suitable for supporting catalytic metal particles. In contrast, a carbon structure exhibiting a Raman D half width at half maximum that is equal to or greater than the above-mentioned lower limit contains carbon with an appropriate degree of crystallinity around the edge portion, making it more suitable for supporting catalytic metal particles, thereby contributing to improving the durability and / or catalytic function of the metal-supported catalyst.

[0061] This catalyst has a BET specific surface area of 350 (m 2 / g-carbon support) or more. In this specification, the numerical unit " / g-carbon support" indicates a value per 1g of the carbon support contained in the present catalyst. On the other hand, the numerical unit " / g" indicates a value per 1g of the present catalyst.

[0062] The BET specific surface area of the catalyst is, for example, 400 (m 2 / g-carbon support) or more is more preferable, and 450 (m 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more is more preferable, and 2 / g-carbon support) or more. The BET specific surface area of the catalyst is, for example, 3000 (m 2 / g-carbon support) or less, and 2 / g-carbon support) or less, and 2 / g-carbon support) or less, and 2 / g-carbon support) or less, and may be 1600 (m 2 / g-carbon support) or less, and 2 / g-carbon support) or less, and 2 / g-carbon support) or less, and 2 / g-carbon support) or less. The BET specific surface area of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0063] The BET specific surface area (m 2 / g-carbon support) is the BET specific surface area (m 2 / g) and the weight ratio of the carbon support contained in the present catalyst obtained by inductively coupled plasma atomic emission spectrometry.

[0064] The catalyst preferably has an average pore diameter of 8.0 nm or less. The average pore diameter of the catalyst is, for example, more preferably 7.0 nm or less, even more preferably 6.0 nm or less, even more preferably 5.0 nm or less, even more preferably 4.5 nm or less, even more preferably 4.0 nm or less, even more preferably 3.5 nm or less, and even more preferably 3.0 nm or less. The average pore diameter of the catalyst may be, for example, 1.0 nm or more, preferably 1.5 nm or more, and particularly preferably 2.0 nm or more. The average pore diameter of the catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The average pore diameter of the catalyst is obtained by the BJH method from a nitrogen adsorption isotherm at a temperature of 77 K.

[0065] If the average pore diameter of a metal-supported catalyst is too large, for example, when the metal-supported catalyst is used as an electrode catalyst for a fuel cell, the ionomer tends to penetrate into the pores of the metal-supported catalyst, and as a result, the catalytic metal particles supported in the pores are coated with the ionomer, which tends to reduce catalytic activity. In contrast, a porous structure having an average pore diameter equal to or less than the above-mentioned upper limit makes it difficult for the ionomer to penetrate into the pores, which contributes to improving durability and / or catalytic function.

[0066] Furthermore, if the average pore diameter of the metal-supported catalyst is too small, the catalytic metal particles are more likely to be supported on the outer surface of the carbon support than inside the pores, resulting in reduced durability. In contrast, a porous structure having an average pore diameter equal to or greater than the above-mentioned lower limit allows the catalytic metal particles to be effectively supported inside the pores, contributing to improved durability.

[0067] In the present catalyst, the ratio of the weight of the precious metal contained in the catalyst (more specifically, the precious metal contained in the catalytic metal particles) to the weight of the present catalyst (hereinafter referred to as the "precious metal content") is preferably 35 wt% or more. The precious metal content of the present catalyst is, for example, more preferably 37 wt% or more, even more preferably 40 wt% or more, even more preferably 42 wt% or more, even more preferably 45 wt% or more, and particularly preferably 47 wt% or more. The precious metal content of the present catalyst may be, for example, 90 wt% or less, 80 wt% or less, 70 wt% or less, or 60 wt% or less. The precious metal content of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The precious metal content of the present catalyst is determined by inductively coupled plasma atomic emission spectroscopy.

[0068] The catalyst preferably has a molar ratio of the precious metal contained in the catalyst to the non-precious metal contained in the catalyst (hereinafter referred to as the "precious metal / non-precious metal molar ratio") of 1.0 or more. The precious metal / non-precious metal molar ratio of the catalyst is, for example, more preferably 1.5 or more, even more preferably 2.0 or more, still more preferably 2.5 or more, and particularly preferably 3.0 or more.

[0069] The noble metal / non-noble metal molar ratio of the present catalyst may be, for example, 20.0 or less, preferably 15.0 or less, more preferably 14.0 or less, even more preferably 13.0 or less, even more preferably 12.0 or less, even more preferably 11.0 or less, and particularly preferably 10.5 or less. The noble metal / non-noble metal molar ratio of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The noble metal / non-noble metal molar ratio of the present catalyst is calculated from the respective molar fractions of the noble metal and non-noble metal contained in the present catalyst obtained by inductively coupled plasma atomic emission spectroscopy.

[0070] The present catalyst preferably has an alloy composition nonuniformity calculated by the following formula (I) of 0.55 or less. JPEG0007720272000005.jpg12170

[0071] In the above formula (I), the theoretical lattice constant and the measured lattice constant are, respectively, the theoretical lattice constant and the measured lattice constant of the precious metal alloy contained in the catalyst. The theoretical lattice constant of the precious metal alloy contained in the catalyst is calculated using the mole fractions of the precious metal and non-precious metal obtained by inductively coupled plasma atomic emission spectroscopy of the catalyst. The measured lattice constant of the precious metal alloy contained in the catalyst is calculated using the peak top position (diffraction angle 2θ) of the diffraction peak corresponding to the (111) plane of the precious metal alloy in the X-ray diffraction pattern obtained by powder X-ray diffraction of the catalyst. When the precious metal alloy contained in the catalyst is a platinum alloy, the peak top position of the diffraction peak corresponding to the (111) plane of the platinum alloy in the X-ray diffraction pattern of the catalyst is in the diffraction angle 2θ range of 35° to 44°.

[0072] The alloy composition heterogeneity of the present catalyst is, for example, more preferably 0.50 or less, even more preferably 0.48 or less, even more preferably 0.45 or less, even more preferably 0.42 or less, even more preferably 0.40 or less, and particularly preferably 0.38 or less. The alloy composition heterogeneity of the present catalyst may be, for example, 0.01 or more, or 0.05 or more. The alloy composition heterogeneity of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. An alloy composition heterogeneity equal to or less than the above-mentioned upper limit values indicates high uniformity in the composition of the precious metal alloy contained in the metal-supported catalyst, contributing to improved durability and / or catalytic function.

[0073] The present catalyst preferably has a half-value asymmetry and a quarter-value asymmetry calculated by the following formulas (II) and (III), respectively, of 0.55 or less. JPEG0007720272000006.jpg11170JPEG0007720272000007.jpg14170

[0074] In the above formula (II) and formula (III), D m is the value of the diffraction angle 2θ at which the diffraction line shows maximum intensity in the range of diffraction angle 2θ at which the diffraction peak of the (111) plane of the precious metal alloy appears in the X-ray diffraction pattern obtained by powder X-ray diffraction of the catalyst (for example, when the precious metal alloy is a platinum alloy, the diffraction angle 2θ is in the range of 35° to 44° at which the diffraction peak of the (111) plane of the platinum alloy appears), and D Lh is the smallest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows half the maximum intensity in the range, and D Hh is the largest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows half the maximum intensity in the range, and D Lq is the smallest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows one-fourth of the maximum intensity in the range, and D Hq is the largest value of the diffraction angle 2θ at which the diffraction line shows one-fourth of the maximum intensity in the range.

[0075] The half-value asymmetry and quarter-value asymmetry of the present catalyst are, for example, more preferably 0.53 or less, even more preferably 0.50 or less, even more preferably 0.48 or less, still more preferably 0.45 or less, and particularly preferably 0.43 or less. The half-value asymmetry and quarter-value asymmetry of the present catalyst may be, for example, 0.01 or more, or 0.05 or more. The half-value asymmetry and quarter-value asymmetry of the present catalyst may each be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. A half-value asymmetry and quarter-value asymmetry equal to or less than the above-mentioned upper limit values indicates high uniformity in the composition of the precious metal alloy contained in the metal-supported catalyst, contributing to improved durability and / or catalytic function.

[0076] The number-average particle diameter of the catalytic metal particles contained in the present catalyst is preferably 8.0 nm or less. The number-average particle diameter of the catalytic metal particles is, for example, preferably 7.5 nm or less, more preferably 7.0 nm or less, even more preferably 6.5 nm or less, even more preferably 6.0 nm or less, even more preferably 5.5 nm or less, even more preferably 5.0 nm or less, even more preferably 4.5 nm or less, even more preferably 4.0 nm or less, and particularly preferably 3.5 nm or less. The number-average particle diameter of the catalytic metal particles may be, for example, 1.0 nm or more, 1.5 nm or more, or 2.0 nm or more. The number-average particle diameter of the catalytic metal particles contained in the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The number-average particle diameter of the catalytic metal particles contained in the present catalyst is obtained by powder X-ray diffraction of the present catalyst. Catalytic metal particles having a number-average particle diameter equal to or less than the above-mentioned upper limit values contribute to improved durability and / or catalytic function. If the number-average particle diameter of the catalytic metal particles is too large, the metallic surface area per unit metallic mass of the catalytic metal particles will be too small, which may result in a deterioration in output characteristics. In contrast, a number-average particle diameter of not more than the above-mentioned upper limit increases the metallic surface area per unit metallic mass of the catalytic metal particles, contributing to an improvement in output characteristics.

[0077] The volume average particle diameter of the catalytic metal particles contained in the present catalyst is preferably 8.0 nm or less. The volume average particle diameter of the catalytic metal particles is, for example, preferably 7.5 nm or less, more preferably 7.0 nm or less, even more preferably 6.5 nm or less, even more preferably 6.0 nm or less, even more preferably 5.5 nm or less, even more preferably 5.0 nm or less, even more preferably 4.5 nm or less, and particularly preferably 4.2 nm or less. The volume average particle diameter of the catalytic metal particles may be, for example, 1.0 nm or more, 1.5 nm or more, or 2.0 nm or more. The volume average particle diameter of the catalytic metal particles contained in the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. The volume average particle diameter of the catalytic metal particles contained in the present catalyst is obtained by powder X-ray diffraction of the present catalyst. If the volume average particle diameter of the catalytic metal particles is too large, the metal surface area per unit metal mass of the catalytic metal particles will be too small, which may result in poor output characteristics, and the large variation in particle diameter will make the metal constituting the surface of the catalytic metal particles more likely to dissolve as metal ions. In contrast, a volume average particle diameter of less than the above-mentioned upper limit increases the metal surface area per unit metal mass of the catalytic metal particles, contributing to improved output characteristics, and suppressing dissolution of the catalytic metal particles, contributing to improved durability and / or catalytic function.

[0078] The present catalyst preferably has a sweep rate dependency of the electrochemically effective specific surface area (ECSA) of the precious metal contained in the present catalyst (hereinafter referred to as "ECSA sweep rate dependency"), calculated by the following formula (IV), of 60% or more. JPEG0007720272000008.jpg19170

[0079] The numerical unit " / g-precious metal" indicates a value per gram of precious metal contained in the catalyst. For example, the numerical unit " / g-Pt" indicates a value per gram of platinum contained in the catalyst.

[0080] In the above formula (IV), "ECSA@1000 mV" and "ECSA@10 mV" are the ECSA (m ) per gram of precious metal contained in the catalyst, obtained by cyclic voltammetry using a rotating ring-disk electrode apparatus having a working electrode on which the catalyst is supported, with a potential sweep rate of 1000 mV / sec and a potential sweep rate of 10 mV / sec, respectively. 2 / g-precious metal) (i.e., "ECSA@1000mV(m 2 / g-precious metal)” and “ECSA@10mV(m 2 / g-precious metals)

[0081] The ECSA sweep rate dependence of the present catalyst is, for example, more preferably 65% or more, even more preferably 70% or more, even more preferably 75% or more, and particularly preferably 80% or more. The ECSA sweep rate dependence of the present catalyst may be, for example, 100% or less, 95% or less, or even 90% or less. The ECSA sweep rate dependence of the present catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0082] For example, when the catalytic metal particles supported on the carbon support in the present catalyst contain platinum as the precious metal, the sweep rate dependency (%) of the ECSA of the platinum contained in the present catalyst is represented by "ECSA@1000 mV" and "ECSA@10 mV" in the above formula (IV), which are the ECSA (m ) per 1 g of platinum contained in the present catalyst, obtained by cyclic voltammetry using a rotating ring-disk electrode device having a working electrode on which the present catalyst is supported, with a potential sweep at a sweep rate of 1000 mV / sec and a potential sweep at a sweep rate of 10 mV / sec, respectively. 2 / g‐Pt) (i.e., "ECSA@1000mV(m 2 / g‐Pt)” and “ECSA@10mV(m 2 / g-Pt)).

[0083] Catalytic metal particles supported inside the pores of the carbon support are less likely to aggregate than catalytic metal particles supported on the outer surface of the carbon support, contributing to improved catalytic activity and / or durability. In this regard, when most of the catalytic metal particles in a metal-supported catalyst are supported on the outer surface of the carbon support, the decrease in ECSA with increasing potential sweep rate in the cyclic voltammetry described above is small. On the other hand, when a large proportion of catalytic metal particles are supported inside the pores of the carbon support, the decrease in ECSA with increasing potential sweep rate in the cyclic voltammetry described above is large. Therefore, the magnitude of the ECSA sweep rate dependence of a metal-supported catalyst reflects the relative amount of catalytic metal particles supported inside the pores of the carbon support to the amount of catalytic metal particles supported on the outer surface of the carbon support of the metal-supported catalyst.

[0084] The method for producing a metal-supported catalyst according to this embodiment (hereinafter referred to as "the method") is a method for producing a metal-supported catalyst comprising a carbon support and catalytic metal particles supported on the carbon support, the catalytic metal particles comprising a precious metal alloy, and preferably includes the following steps: a first impregnation step of impregnating the carbon support with a precursor of one of a precious metal and a non-precious metal (hereinafter referred to as "first metal") constituting the precious metal alloy; a first gas-phase reduction step of subjecting the carbon support impregnated with the precursor of the first metal to a gas-phase reduction treatment to obtain a first metal-supported catalyst supporting the first metal; a second impregnation step of impregnating the first metal-supported catalyst with a precursor of the other of the precious metal and the non-precious metal (hereinafter referred to as "second metal"); and a second gas-phase reduction step of subjecting the first metal-supported catalyst impregnated with the precursor of the second metal to a gas-phase reduction treatment, followed by an alloying treatment to obtain a metal-supported catalyst supporting catalytic metal particles comprising an alloy of the first metal and the second metal.

[0085] In the first impregnation step, a carbon support that has not yet been impregnated with a precursor of either a precious metal or a non-precious metal to constitute the precious metal alloy contained in the catalytic metal particles is impregnated with a precursor of a first metal. The first metal may be either a precious metal or a non-precious metal to constitute the precious metal alloy contained in the catalytic metal particles, but if a non-precious metal with a high ionization tendency is selected as the first metal, the non-precious first metal will be ionized when the precious metal, the second metal, is impregnated in the second impregnation step. Therefore, it is preferable to select a precious metal with a lower ionization tendency.

[0086] In the present method, when a precious metal alloy containing two or more precious metals and / or two or more non-precious metals is formed, the first impregnation step may involve impregnating the carbon support with a precursor of only one precious metal or a precursor of only one non-precious metal as the first metal precursor, or with precursors of two or more precious metals or precursors of two or more non-precious metals. Furthermore, when two or more first metal precursors are impregnated into the carbon support, the first impregnation step may involve, for example, first impregnating the carbon support with a precursor of one of the two or more first metals and then impregnating the carbon support with a precursor of the other first metal, or it may involve simultaneously impregnating the carbon support with precursors of two or more first metals.

[0087] The method for impregnating the carbon support with a precursor of the first metal is not particularly limited as long as the effects of the present invention can be obtained, but for example, it is preferable to impregnate the carbon support with a solution containing the precursor of the first metal. Here, when the carbon support is impregnated with precursors of two or more first metals, the first impregnation step may include, for example, first impregnating the carbon support with a solution containing a precursor of one of the two or more first metals, and then impregnating the carbon support with a solution containing a precursor of the other first metal, or may include impregnating the carbon support with a solution containing precursors of two or more first metals.

[0088] The pressure (atmospheric pressure) of the atmosphere in which the first impregnation step is carried out is not particularly limited as long as the effects of the present invention can be obtained, and may be normal pressure (atmospheric pressure), but the first impregnation step preferably includes, for example, maintaining a solution containing a precursor of the first metal and the carbon support under reduced pressure. By maintaining a solution containing a precursor of the first metal and the carbon support under reduced pressure, the inside of the pores of the carbon support is effectively degassed, and the precursor is effectively impregnated into the inside of the pores.

[0089] The pressure of the reduced pressure atmosphere for holding the solution containing the first metal precursor and the carbon support is not particularly limited as long as the effects of the present invention can be obtained, but may be, for example, a gauge pressure of −0.02 MPa (minus 0.02 MPa) or less, preferably −0.04 MPa or less, more preferably −0.06 MPa or less, even more preferably −0.08 MPa or less, and particularly preferably −0.10 MPa or less. Furthermore, the gauge pressure of the reduced pressure atmosphere for holding the solution containing the first metal precursor and the carbon support may be, for example, a gauge pressure of −0.1013 MPa or more. The pressure of the reduced pressure atmosphere for holding the solution containing the first metal precursor and the carbon support may be specified by any combination of the above-mentioned lower limit and any of the above-mentioned upper limit.

[0090] In the first impregnation step, the time for which the solution containing the first metal precursor and the carbon support is held under reduced pressure is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 10 minutes or more, preferably 20 minutes or more, more preferably 30 minutes or more, even more preferably 40 minutes or more, even more preferably 50 minutes or more, and particularly preferably 55 minutes or more. Furthermore, the time for which the solution containing the first metal precursor and the carbon support is held under reduced pressure may be, for example, 24 hours or less, 5 hours or less, or 3 hours or less. The time for which the solution containing the first metal precursor and the carbon support is held under reduced pressure may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0091] The first impregnation step preferably includes holding the solution containing the precursor of the first metal and the carbon support under pressure, whereby the precursor is effectively impregnated into the pores of the carbon support.

[0092] The pressure of the pressurized atmosphere holding the solution containing the first metal precursor and the carbon support is not particularly limited as long as the effects of the present invention can be obtained, but may be, for example, 0.03 MPa or more in gauge pressure, preferably 0.06 MPa or more, more preferably 0.09 MPa or more, even more preferably 0.12 MPa or more, and particularly preferably 0.15 MPa or more in gauge pressure. Furthermore, the pressure of the pressurized atmosphere holding the solution containing the first metal precursor and the carbon support may be, for example, 10 MPa or less in gauge pressure, or 5 MPa or less. The pressure of the pressurized atmosphere holding the solution containing the first metal precursor and the carbon support may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0093] In the first impregnation step, the time for which the solution containing the first metal precursor and the carbon support is held under pressure is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 10 minutes or more, preferably 20 minutes or more, more preferably 30 minutes or more, even more preferably 40 minutes or more, even more preferably 50 minutes or more, and particularly preferably 55 minutes or more. Furthermore, the time for which the solution containing the first metal precursor and the carbon support is held under pressure may be, for example, 24 hours or less, 5 hours or less, or 3 hours or less. The time for which the solution containing the first metal precursor and the carbon support is held under pressure may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0094] The first impregnation step preferably includes first holding the solution containing the precursor of the first metal and the carbon support under reduced pressure and then holding it under pressure, in which case the precursor of the first metal is very effectively impregnated into the pores of the carbon support.

[0095] The first impregnation step preferably includes mixing the solution containing the precursor of the first metal and the carbon support with stirring before holding the solution containing the precursor of the first metal and the carbon support under reduced pressure and / or before holding the solution containing the precursor of the first metal and the carbon support under pressure. By mixing the solution containing the precursor of the first metal and the carbon support with stirring before holding under reduced pressure and / or before holding under pressure, the precursor is effectively impregnated into the pores of the carbon support.

[0096] Furthermore, the first impregnation step preferably includes mixing the solution containing the precursor of the first metal and the carbon support under stirring after holding the solution containing the precursor of the first metal and the carbon support under reduced pressure and / or holding the solution containing the precursor of the first metal and the carbon support under pressure. By mixing the solution containing the precursor of the first metal and the carbon support under stirring after holding under reduced pressure and / or holding under pressure, the precursor is effectively impregnated into the pores of the carbon support.

[0097] The time for stirring and mixing the solution containing the first metal precursor and the carbon support is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 0.1 hours or more, preferably 0.5 hours or more, more preferably 1 hour or more, even more preferably 5 hours or more, even more preferably 10 hours or more, even more preferably 18 hours or more, even more preferably 24 hours or more, even more preferably 35 hours or more, even more preferably 50 hours or more, and particularly preferably 65 hours or more. Furthermore, this stirring and mixing time may be, for example, 120 hours or less, 96 hours or less, or 72 hours or less. The time for stirring and mixing the solution containing the first metal precursor and the carbon support may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0098] The temperature (air temperature) of the atmosphere in which the first impregnation step is carried out is not particularly limited as long as the effects of the present invention can be obtained, and may be room temperature (e.g., about 25°C). However, the first impregnation step preferably includes, for example, maintaining a solution containing a precursor of the first metal and the carbon support at a low temperature. By maintaining a solution containing a precursor of the first metal and the carbon support at a low temperature, adsorption is promoted by equilibrium shift and / or dissolution of gas molecules is promoted, and the precursor is effectively impregnated into the pores of the carbon support.

[0099] That is, the first impregnation step preferably includes holding a solution containing a precursor of the first metal and the carbon support under reduced pressure at a low temperature. The first impregnation step preferably includes holding a solution containing a precursor of the first metal and the carbon support under pressure at a low temperature. The first impregnation step preferably includes mixing the solution containing the precursor of the first metal and the carbon support with stirring at a low temperature before holding the solution containing the precursor of the first metal and the carbon support under reduced pressure and / or before holding the solution containing the precursor of the first metal and the carbon support under pressure. The first impregnation step preferably includes mixing the solution containing the precursor of the first metal and the carbon support with stirring at a low temperature after holding the solution containing the precursor of the first metal and the carbon support under reduced pressure and / or after holding the solution containing the precursor of the first metal and the carbon support under pressure.

[0100] In the first impregnation step, the low temperature at which the solution containing the first metal precursor and the carbon support is maintained is not particularly limited as long as the effects of the present invention can be obtained, but is, for example, preferably 20°C or lower, more preferably 15°C or lower, even more preferably 10°C or lower, and particularly preferably 5°C or lower. Furthermore, the low temperature at which the solution containing the first metal precursor and the carbon support is maintained may be, for example, above 0°C or may be 1°C or higher. The low temperature at which the solution containing the first metal precursor and the carbon support is maintained may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0101] In the first gas-phase reduction step, the carbon support impregnated with the precursor of the first metal in the first impregnation step is subjected to a gas-phase reduction treatment (hereinafter referred to as the "first gas-phase reduction treatment") to obtain a first metal-supported catalyst containing the carbon support and the first metal supported on the carbon support.

[0102] In the first gas-phase reduction step, it is preferable to perform the first gas-phase reduction treatment on a solid obtained by drying a solution containing a carbon support impregnated with a first metal precursor. In this case, the temperature at which the solution containing a carbon support impregnated with a first metal precursor is dried is not particularly limited as long as the effects of the present invention are obtained. For example, the temperature may be 40°C or higher, preferably 60°C or higher, more preferably 80°C or higher, and particularly preferably 100°C or higher. Furthermore, the drying temperature may be, for example, 200°C or lower, preferably 190°C or lower, more preferably 180°C or lower, even more preferably 170°C or lower, and particularly preferably 160°C or lower. The temperature at which the solution containing a carbon support impregnated with a first metal precursor is dried may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. If the temperature at which the solution containing a carbon support impregnated with a first metal precursor is dried is too low, it may take a long time to sufficiently remove the solvent, which may result in the first metal precursor adsorbed on the carbon support being desorbed. Furthermore, if the temperature for drying the solution containing the carbon support impregnated with the precursor of the first metal is too high, the oxidation of the carbon support and / or bumping of the solution may prevent the first metal from being uniformly supported on the carbon support. Therefore, it is preferable to adopt a temperature within the above-mentioned range as the temperature for drying the solution containing the carbon support impregnated with the precursor of the first metal.

[0103] The first gas-phase reduction treatment is carried out by heating the carbon support impregnated with the precursor of the first metal in a reducing atmosphere. The reducing atmosphere in which the first gas-phase reduction treatment is carried out is not particularly limited as long as the effects of the present invention can be obtained, but is preferably an atmosphere containing one or more reducing gases selected from the group consisting of hydrogen gas, ammonia gas, and carbon monoxide gas.

[0104] The concentration of the reducing gas in the reducing atmosphere is not particularly limited as long as the effects of the present invention are obtained, but for example, it is preferably 50% by volume or more, more preferably 60% by volume or more, even more preferably 70% by volume or more, even more preferably 80% by volume or more, even more preferably 90% by volume or more, even more preferably 95% by volume or more, and particularly preferably 100% by volume.

[0105] The temperature at which the carbon support impregnated with the first metal precursor is heated in the first gas-phase reduction treatment (hereinafter referred to as the "first reduction heating temperature") is not particularly limited as long as the effects of the present invention are obtained. For example, the temperature is preferably 100°C or higher, more preferably 150°C or higher, even more preferably 200°C or higher, even more preferably 250°C or higher, and particularly preferably 300°C or higher. The first reduction heating temperature may be, for example, 550°C or lower, preferably 500°C or lower, more preferably 450°C or lower, and particularly preferably 400°C or lower. The first reduction heating temperature may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. By adopting a temperature within the above-mentioned range as the first reduction heating temperature, the first metal precursor can be efficiently reduced while preventing excessive aggregation of the first metal particles.

[0106] The time for heating at the first reduction heating temperature in the first gas-phase reduction treatment (hereinafter referred to as the "first reduction heating time") is not particularly limited as long as the effects of the present invention are obtained, but is, for example, preferably 10 minutes or more, more preferably 30 minutes or more, even more preferably 60 minutes or more, even more preferably 90 minutes or more, and particularly preferably 100 minutes or more. The first reduction heating time may be, for example, 24 hours or less, preferably 12 hours or less, more preferably 6 hours or less, and particularly preferably 3 hours or less. The first reduction heating time may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. By adopting a time within the above-mentioned range as the first reduction heating time, it is possible to effectively prevent excessive aggregation of particles of the first metal while sufficiently progressing the reduction of the precursor of the first metal.

[0107] In the second impregnation step, the first metal supported catalyst obtained in the first vapor-phase reduction step is impregnated with a precursor of a second metal, which is a non-noble metal when the first metal is a noble metal, or a noble metal when the first metal is a non-noble metal.

[0108] In the case where the carbon support is impregnated with a precursor of a precious metal in the first impregnation step, the second impregnation step is preferably a step in which the carbon support is impregnated with a precursor of a non-precious metal for the first time after the first impregnation step. In the case where the carbon support is impregnated with a precursor of a non-precious metal in the first impregnation step, the second impregnation step is preferably a step in which the carbon support is impregnated with a precursor of a precious metal for the first time after the first impregnation step.

[0109] In the present method, when a precious metal alloy containing two or more precious metals and / or two or more non-precious metals is formed, the second impregnation step may involve impregnating the first metal-supported catalyst with only one precursor of the precious metal or only one precursor of the non-precious metal as the second metal precursor, or with two or more precursors of the precious metal or two or more precursors of the non-precious metal. When two or more precursors of the second metals are impregnated into the first metal-supported catalyst, the second impregnation step may involve, for example, first impregnating the first metal-supported catalyst with a precursor of one of the two or more second metals and then impregnating the first metal-supported catalyst with a precursor of the other second metal, or may involve simultaneously impregnating the first metal-supported catalyst with precursors of two or more second metals.

[0110] The method for impregnating the first metal-supported catalyst with a precursor of the second metal is not particularly limited as long as the effects of the present invention can be obtained, but for example, it is preferable to impregnate the first metal-supported catalyst with a solution containing a precursor of the second metal. Here, when the first metal-supported catalyst is impregnated with precursors of two or more second metals, the second impregnation step may include, for example, first impregnating the first metal-supported catalyst with a solution containing a precursor of one of the two or more second metals, and then impregnating the first metal-supported catalyst with a solution containing a precursor of the other second metal, or may include impregnating the first metal-supported catalyst with a solution containing precursors of two or more second metals.

[0111] The pressure (atmospheric pressure) of the atmosphere in which the second impregnation step is carried out is not particularly limited as long as the effects of the present invention can be obtained, and may be normal pressure (atmospheric pressure), but the second impregnation step preferably includes, for example, maintaining a solution containing a precursor of the second metal and a first metal-supported catalyst under reduced pressure. By maintaining a solution containing a precursor of the second metal and a first metal-supported catalyst under reduced pressure, the inside of the pores of the first metal-supported catalyst is effectively degassed, and the precursor is effectively impregnated into the inside of the pores.

[0112] The pressure of the reduced pressure atmosphere holding the solution containing the second metal precursor and the first metal supported catalyst is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, a gauge pressure of −0.02 MPa (minus 0.02 MPa) or less, preferably −0.04 MkPa or less, more preferably −0.06 MkPa or less, even more preferably −0.08 MPa or less, and particularly preferably −0.10 MPa or less. Furthermore, the pressure of the reduced pressure atmosphere holding the solution containing the second metal precursor and the first metal supported catalyst may be, for example, a gauge pressure of −0.1013 MPa or more. The pressure of the reduced pressure atmosphere holding the solution containing the second metal precursor and the first metal supported catalyst may be specified by any combination of the above-mentioned lower limit and any of the above-mentioned upper limit.

[0113] In the second impregnation step, the time for which the solution containing the second metal precursor and the first metal-supported catalyst is held under reduced pressure is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 10 minutes or more, preferably 20 minutes or more, more preferably 30 minutes or more, even more preferably 40 minutes or more, even more preferably 50 minutes or more, and particularly preferably 55 minutes or more. Furthermore, the time for which the solution containing the second metal precursor and the first metal-supported catalyst is held under reduced pressure may be, for example, 24 hours or less, 5 hours or less, or 3 hours or less. The time for which the solution containing the second metal precursor and the first metal-supported catalyst is held under reduced pressure may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0114] The second impregnation step preferably includes holding the solution containing the second metal precursor and the first metal supported catalyst under pressure, whereby the precursor is effectively impregnated into the pores of the carbon support.

[0115] The pressure of the pressurized atmosphere holding the solution containing the second metal precursor and the first metal supported catalyst is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, a gauge pressure of 0.03 MPa or more, preferably 0.06 MPa or more, more preferably 0.09 MPa or more, even more preferably 0.12 MPa or more, and particularly preferably 0.15 MPa or more. Furthermore, the pressure of the pressurized atmosphere holding the solution containing the second metal precursor and the first metal supported catalyst may be, for example, a gauge pressure of 10 MPa or less, or 5 MPa or less. The pressure of the pressurized atmosphere holding the solution containing the second metal precursor and the first metal supported catalyst may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0116] In the second impregnation step, the time for which the solution containing the second metal precursor and the first metal-supported catalyst is held under pressure is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 10 minutes or more, preferably 20 minutes or more, more preferably 30 minutes or more, even more preferably 40 minutes or more, even more preferably 50 minutes or more, and particularly preferably 55 minutes or more. Furthermore, the time for which the solution containing the second metal precursor and the first metal-supported catalyst is held under pressure may be, for example, 24 hours or less, 5 hours or less, or 3 hours or less. The time for which the solution containing the second metal precursor and the first metal-supported catalyst is held under pressure may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0117] The second impregnation step preferably includes first holding the solution containing the second metal precursor and the first metal supported catalyst under reduced pressure and then holding it under increased pressure, in which case the second metal precursor is highly effectively impregnated into the pores of the first metal supported catalyst.

[0118] The second impregnation step preferably includes mixing the solution containing the second metal precursor and the first metal-supported catalyst with stirring before holding the solution containing the second metal precursor and the first metal-supported catalyst under reduced pressure and / or before holding the solution containing the second metal precursor and the first metal-supported catalyst under pressure. By mixing the solution containing the second metal precursor and the first metal-supported catalyst with stirring before holding under reduced pressure and / or before holding under pressure, the precursor is effectively impregnated into the pores of the first metal-supported catalyst.

[0119] The second impregnation step preferably includes mixing the solution containing the second metal precursor and the first metal-supported catalyst under agitation after holding the solution containing the second metal precursor and the first metal-supported catalyst under reduced pressure and / or after holding the solution containing the second metal precursor and the first metal-supported catalyst under pressure. By mixing the solution containing the second metal precursor and the first metal-supported catalyst under agitation after holding under reduced pressure and / or after holding under pressure, the precursor is effectively impregnated into the pores of the first metal-supported catalyst.

[0120] The time for stirring and mixing the solution containing the second metal precursor and the first metal-supported catalyst is not particularly limited as long as the effects of the present invention are obtained, but may be, for example, 0.1 hours or more, preferably 0.5 hours or more, more preferably 1 hour or more, even more preferably 5 hours or more, even more preferably 10 hours or more, even more preferably 18 hours or more, even more preferably 24 hours or more, even more preferably 35 hours or more, even more preferably 50 hours or more, and particularly preferably 65 hours or more. Furthermore, this stirring and mixing time may be, for example, 120 hours or less, 96 hours or less, or 72 hours or less. The time for stirring and mixing the solution containing the second metal precursor and the first metal-supported catalyst may be specified by any combination of the above-mentioned lower limit and any of the above-mentioned upper limit.

[0121] The temperature (air temperature) of the atmosphere in which the second impregnation step is carried out is not particularly limited as long as the effects of the present invention can be obtained, and may be room temperature (e.g., about 25°C), but the second impregnation step preferably includes, for example, maintaining a solution containing a second metal precursor and a first metal-supported catalyst at a low temperature. By maintaining a solution containing a second metal precursor and a first metal-supported catalyst at a low temperature, adsorption is promoted by equilibrium shift and / or dissolution of gas molecules is promoted, and the precursor is effectively impregnated into the pores of the first metal-supported catalyst.

[0122] That is, the second impregnation step preferably includes holding a solution containing a second metal precursor and a first metal-supported catalyst under reduced pressure at a low temperature. The second impregnation step preferably includes holding a solution containing a second metal precursor and a first metal-supported catalyst under pressure at a low temperature. The second impregnation step preferably includes mixing the solution containing the second metal precursor and the first metal-supported catalyst with stirring at a low temperature before holding the solution containing the second metal precursor and the first metal-supported catalyst under reduced pressure and / or before holding the solution containing the second metal precursor and the first metal-supported catalyst under pressure. The second impregnation step preferably includes mixing the solution containing the second metal precursor and the first metal-supported catalyst with stirring at a low temperature after holding the solution containing the second metal precursor and the first metal-supported catalyst under reduced pressure and / or after holding the solution containing the second metal precursor and the first metal-supported catalyst under pressure.

[0123] In the second impregnation step, the low temperature at which the solution containing the second metal precursor and the first metal supported catalyst is maintained is not particularly limited as long as the effects of the present invention can be obtained, but is, for example, preferably 20°C or lower, more preferably 15°C or lower, even more preferably 10°C or lower, and particularly preferably 5°C or lower. Furthermore, the low temperature at which the solution containing the second metal precursor and the first metal supported catalyst is maintained may be, for example, above 0°C or 1°C or higher. The low temperature at which the solution containing the second metal precursor and the first metal supported catalyst is maintained may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0124] In the second gas-phase reduction step, the first metal-supported catalyst impregnated with the precursor of the second metal in the second impregnation step is subjected to a gas-phase reduction treatment (hereinafter referred to as the "second gas-phase reduction treatment"), and then an alloying treatment is performed to obtain a metal-supported catalyst supported on catalytic metal particles containing an alloy of the first metal and the second metal (i.e., a precious metal alloy which is an alloy of a precious metal and a non-precious metal).

[0125] In the second gas-phase reduction step, it is preferable to subject the solid obtained by drying the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal to the second gas-phase reduction treatment. In this case, the temperature at which the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal is dried is not particularly limited as long as the effects of the present invention are obtained. For example, it may be 40°C or higher, preferably 60°C or higher, more preferably 80°C or higher, and particularly preferably 100°C or higher. Furthermore, the temperature at which the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal is dried may be, for example, 200°C or lower, preferably 180°C or lower, more preferably 160°C or lower, even more preferably 140°C or lower, and particularly preferably 110°C or lower. The temperature at which the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal is dried may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. If the temperature for drying the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal is too low, it may take a long time to sufficiently remove the solvent, resulting in the desorption of the precursor of the second metal adsorbed on the first metal-supported catalyst. Furthermore, if the temperature for drying the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal is too high, for example, oxidation of the carbon support and / or bumping of the solution may prevent the second metal from being uniformly supported on the carbon support. Therefore, it is preferable to use a temperature within the above-mentioned range as the temperature for drying the solution containing the first metal-supported catalyst impregnated with the precursor of the second metal.

[0126] The second gas-phase reduction treatment is carried out by heating the first metal-supported catalyst impregnated with the precursor of the second metal in a reducing atmosphere. The reducing atmosphere in which the second gas-phase reduction treatment is carried out is not particularly limited as long as the effects of the present invention can be obtained, but is preferably an atmosphere containing one or more reducing gases selected from the group consisting of hydrogen gas, ammonia gas, and carbon monoxide gas.

[0127] The concentration of the reducing gas in the reducing atmosphere is not particularly limited as long as the effects of the present invention are obtained, but for example, it is preferably 50% by volume or more, more preferably 60% by volume or more, even more preferably 70% by volume or more, even more preferably 80% by volume or more, even more preferably 90% by volume or more, even more preferably 95% by volume or more, and particularly preferably 100% by volume.

[0128] The temperature at which the first metal-supported catalyst impregnated with the second metal precursor is heated in the second gas-phase reduction treatment (hereinafter referred to as the "second reduction heating temperature") is not particularly limited as long as the effects of the present invention are obtained. For example, the temperature is preferably 500°C or higher, more preferably 550°C or higher, even more preferably 600°C or higher, and particularly preferably 650°C or higher. The second reduction heating temperature may be, for example, 1300°C or lower, preferably 1100°C or lower, more preferably 1000°C or lower, and particularly preferably 900°C or lower. The second reduction heating temperature may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. By adopting a temperature within the above-mentioned range as the second reduction heating temperature, the second metal precursor can be efficiently reduced while preventing excessive aggregation of the second metal particles.

[0129] The time for heating at the second reduction heating temperature in the second gas-phase reduction treatment (hereinafter referred to as the "second reduction heating time") is not particularly limited as long as the effects of the present invention are obtained, but is, for example, preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, even more preferably 40 minutes or more, and particularly preferably 50 minutes or more. The second reduction heating time may be, for example, 24 hours or less, preferably 12 hours or less, more preferably 6 hours or less, and particularly preferably 3 hours or less. The second reduction heating time may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. By adopting a time within the above-mentioned range as the second reduction heating time, it is possible to effectively prevent excessive aggregation of particles of the second metal while sufficiently progressing the reduction of the precursor of the second metal.

[0130] The alloying treatment is carried out by heating the metal-supported catalyst carrying the first metal and the second metal after the second gas-phase reduction treatment at a temperature at which an alloy between the first metal and the second metal is formed (hereinafter referred to as the "alloying heating temperature").

[0131] The alloying heating temperature is not particularly limited as long as the effects of the present invention can be obtained, but is preferably 500°C or higher, more preferably 550°C or higher, even more preferably 600°C or higher, and particularly preferably 650°C or higher. The alloying heating temperature may be, for example, 1300°C or lower, preferably 1100°C or lower, more preferably 1000°C or lower, and particularly preferably 900°C or lower. The alloying heating temperature may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. By adopting a temperature within the above-mentioned range as the alloying heating temperature, alloying can proceed while preventing excessive aggregation of alloy particles.

[0132] The time for heating at the alloying heating temperature in the alloying treatment (hereinafter referred to as "alloying heating time") is not particularly limited as long as the effects of the present invention are obtained, but is, for example, preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, even more preferably 40 minutes or more, and particularly preferably 50 minutes or more. The alloying heating time may be, for example, 24 hours or less, preferably 12 hours or less, more preferably 6 hours or less, and particularly preferably 3 hours or less. The alloying heating time may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values. By adopting a time within the above-mentioned range as the alloying heating time, excessive aggregation of alloy particles can be effectively prevented while allowing alloying to proceed sufficiently.

[0133] The atmosphere in which the alloying treatment is performed is not particularly limited as long as the effects of the present invention can be obtained, but is preferably an inert gas atmosphere or a vacuum. The atmosphere in which the alloying treatment is performed is not particularly limited as long as the effects of the present invention can be obtained, but is preferably an atmosphere containing one or more inert gases selected from the group consisting of nitrogen gas, argon gas, and helium gas.

[0134] The concentration of the inert gas in the inert gas atmosphere is not particularly limited as long as the effects of the present invention are obtained, but for example, it is preferably 50% by volume or more, more preferably 60% by volume or more, even more preferably 70% by volume or more, even more preferably 80% by volume or more, even more preferably 90% by volume or more, even more preferably 95% by volume or more, and particularly preferably 100% by volume.

[0135] In the second gas-phase reduction step, the second reduction heating temperature and the alloying heating temperature may be determined independently. However, for example, the second reduction heating temperature is preferably a temperature at which the reduction of the second metal proceeds and also at which the alloying of the second metal and the first metal proceeds.

[0136] That is, in the second gas-phase reduction step, for example, it is preferable to heat the first metal-supported catalyst impregnated with a precursor of the second metal in a reducing atmosphere at a second reduction heating temperature at which alloying of the first metal and the second metal proceeds. In this case, in the second gas-phase reduction treatment, the reduction of the precursor of the second metal and the alloying of the second metal and the first metal can proceed in parallel, which effectively reduces, for example, the time and cost required for producing the metal-supported catalyst. Furthermore, by proceeding in parallel with the reduction of the precursor of the second metal and the alloying of the second metal and the first metal, the time from the reduction of the precursor to alloying is shortened, which effectively suppresses the aggregation of unalloyed metal particles, and as a result, the support of alloy particles having a uniform alloy composition is achieved.

[0137] The second reduction heating temperature at which alloying proceeds is, for example, preferably 500°C or higher, more preferably 550°C or higher, even more preferably 600°C or higher, and particularly preferably 650°C or higher. The second reduction heating temperature at which alloying proceeds may be, for example, 1300°C or lower, preferably 1100°C or lower, more preferably 1000°C or lower, and particularly preferably 900°C or lower. The second reduction heating temperature at which alloying proceeds may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0138] In addition, alloying in a reducing atmosphere may deteriorate the carbon support. In this regard, in the second gas-phase reduction step, the second metal is first reduced by performing a second gas-phase reduction treatment in a reducing atmosphere at a second reduction heating temperature at which alloying proceeds, and then alloying treatment is further performed in an inert gas atmosphere, thereby effectively alloying the first metal and the second metal supported on the carbon support while suppressing deterioration of the carbon support.

[0139] In the second gas-phase reduction step, the timing of the alloying treatment is not particularly limited as long as it is performed after the second gas-phase reduction treatment, but it is preferable to perform the second gas-phase reduction treatment and the alloying treatment consecutively in one container. That is, in the second gas-phase reduction step, for example, it is preferable to first perform the second gas-phase reduction treatment in a reducing atmosphere in a container, then exchange the reducing atmosphere in the container for an inert gas atmosphere, and then perform the alloying treatment in the inert gas atmosphere in the container.

[0140] In this case, in the second gas-phase reduction step, it is preferable to first carry out a second gas-phase reduction treatment at a second reduction heating temperature in a reducing atmosphere in a container, and then replace the reducing atmosphere in the container with an inert gas atmosphere while maintaining the temperature in the container at a temperature that is 200°C or less, preferably 150°C or less, more preferably 100°C or less, even more preferably 70°C or less, and particularly preferably 50°C or less, different from the second reduction temperature.

[0141] Furthermore, in this case, after replacing the reducing atmosphere in the container with an inert gas atmosphere, it is preferable to carry out alloying treatment in the inert gas atmosphere in the container at an alloying heating temperature that is 200°C or less, preferably 150°C or less, more preferably 100°C or less, even more preferably 50°C or less, even more preferably 30°C or less, and particularly preferably 10°C or less, different from the second reduction heating temperature.

[0142] The present method may further include a post-treatment step after the second gas-phase reduction step. In the post-treatment step, the metal-supported catalyst obtained in the second gas-phase reduction step is subjected to a treatment for removing excess metal and / or a treatment for removing precious metal oxide. The treatment for removing excess metal is not particularly limited as long as the effects of the present invention are obtained, but is preferably, for example, a washing treatment using an acid such as nitric acid. The treatment for removing precious metal oxide is not particularly limited as long as the effects of the present invention are obtained, but is preferably, for example, a heat treatment in an inert gas atmosphere such as a nitrogen atmosphere. In the post-treatment step, subjecting the metal-supported catalyst to a heat treatment in an inert gas atmosphere removes oxides on the metal surface generated in the treatment for removing excess metal and / or reduces metal surface roughness, contributing to improved durability and / or catalytic function.

[0143] The temperature at which the metal-supported catalyst is heated in an inert gas atmosphere in the post-treatment step (hereinafter referred to as "post-treatment heating temperature") is not particularly limited as long as the effects of the present invention are obtained, but is, for example, preferably 500°C or higher, more preferably 550°C or higher, even more preferably 600°C or higher, and particularly preferably 650°C or higher. The post-treatment heating temperature may be, for example, 1300°C or lower, preferably 1100°C or lower, more preferably 1000°C or lower, and particularly preferably 900°C or lower. The post-treatment heating temperature may be specified by any combination of any of the above-mentioned lower limit values and any of the above-mentioned upper limit values.

[0144] The present method may further include an impregnation step and / or a gas-phase reduction step. That is, the present method may further include, for example, a third impregnation step in which a precursor of the first metal, the second metal, or a third metal different from the first metal and the second metal is further impregnated after the second gas-phase reduction step described above, and a third gas-phase reduction step in which a gas-phase reduction treatment and an alloying treatment are further performed after the third impregnation step. In this case, the third impregnation step is not particularly limited as long as the effects of the present invention are obtained, but it is preferably performed in the same manner as the first impregnation step or the second impregnation step described above. Furthermore, the third gas-phase reduction step is not particularly limited as long as the effects of the present invention are obtained, but it is preferably performed in the same manner as the first gas-phase reduction step or the second gas-phase reduction step described above.

[0145] According to the present method, a metal-supported catalyst having a high noble metal content and excellent durability and catalytic function can be produced. That is, the present catalyst described above is preferably produced by the present method.

[0146] The electrode according to this embodiment (hereinafter referred to as "the electrode") contains the catalyst. That is, the electrode is, for example, a battery electrode containing an electrode substrate and the catalyst supported on the electrode substrate. The electrode is preferably a battery electrode. That is, the electrode is preferably an electrode of, for example, a fuel cell (e.g., a polymer electrolyte fuel cell), an air cell, a water electrolyzer (e.g., a polymer electrolyte water electrolyzer), a redox flow battery, or a halogen battery.

[0147] The electrode may be either a cathode or an anode, but is preferably a cathode, i.e., the electrode is the cathode or anode, preferably a cathode, of a fuel cell, air cell, water electrolyzer, redox flow battery, or halogen battery.

[0148] The battery according to this embodiment (hereinafter referred to as "this battery") includes this electrode. Specifically, this battery is preferably a fuel cell (e.g., a polymer electrolyte fuel cell), an air battery, a redox flow battery, or a halogen battery that includes this electrode. This battery preferably has a membrane electrode assembly (MEA) that includes this electrode.

[0149] The present battery is a battery having the present electrode as a cathode or an anode, preferably a battery having the present electrode as a cathode. That is, the present battery is a fuel cell, air battery, redox flow battery, or halogen battery having the present electrode as a cathode or an anode, preferably a fuel cell, air battery, redox flow battery, or halogen battery having the present electrode as a cathode.

[0150] Next, a specific example according to this embodiment will be described. [Example]

[0151] [Manufacturing of carbon supports] 1.0 g of polyacrylonitrile (PAN), 1.0 g of 2-methylimidazole, 6.0 g of zinc chloride (ZnCl), and 30 g of dimethylformamide were mixed. The resulting mixture was dried to remove the solvent. The dried mixture was heated in an air atmosphere to 250°C for infusibility.

[0152] The infusibilized mixture was heated to 1500°C under a gauge pressure of 0.90 MPa in a nitrogen atmosphere to carbonize it. Dilute hydrochloric acid was added to the carbonized material obtained by carbonization and stirred. The suspension containing the carbonized material was then filtered using a filter membrane, and the carbonized material was washed with distilled water until the filtrate became neutral. In this way, metal removal treatment by acid washing was performed.

[0153] The carbonized material after the metal removal treatment was pulverized using a fine grinder until the median particle size was 0.4 μm or less. The pulverized carbonized material was vacuum dried to remove moisture. The carbonized material was then subjected to a heat treatment at 300°C in a nitrogen atmosphere. The carbonized material obtained in this manner was used as the carbon support C1500.

[0154] Further, a carbonized material obtained in the same manner as in the case of the carbon support C1500, except that the carbonization temperature was changed from 1500°C to 2000°C, was used as the carbon support C2000.

[0155] Furthermore, the carbon support C1500 was graphitized by heating it in a nitrogen atmosphere under atmospheric pressure at 1700°C, 1800°C, 1900°C, 2000°C, 2100°C, 2200°C, or 2400°C. The carbonized materials obtained by the graphitization treatments at 1800°C, 1900°C, 2000°C, 2100°C, 2200°C, and 2400°C were used as carbon supports C1500-G1700, C1500-G1800, C1500-G1900, C1500-G2000, C1500-G2100, C1500-G2200, and C1500-G2400, respectively.

[0156] Commercially available Ketjenblack (EC600JD, manufactured by Lion Specialty Chemicals Co., Ltd.) was used as the carbon support KB. The carbon support KB was graphitized by heating it at 2000°C under atmospheric pressure in a nitrogen atmosphere. The carbon material obtained by this graphitization process was used as the carbon support KB-G2000.

[0157] [Production of metal-supported catalysts] In Examples 1, 3 to 6, 14, C1, C5, and C7 to C10, catalytic metal particles were supported on a carbon support by the following vapor-phase reduction method. First, a first impregnation step was performed. Specifically, 1 g of the carbon support and 22.2 g of an aqueous solution containing chloroplatinic acid (HPtCl), a platinum precursor, in an amount sufficient to achieve a platinum concentration of 5 wt % (1.11 g platinum content) were mixed and stirred for 1 hour. The mixed solution was first maintained under a reduced pressure of −0.10 MPa or less (specifically, −0.10 MPa to −0.1013 MPa) for 1 hour, then maintained under an increased pressure of 0.15 MPa or more (specifically, 0.15 MPa to 0.20 MPa) for 1 hour, and then stirred and mixed for 66 hours. This first impregnation step was performed while maintaining the temperature of the mixed solution at 5°C or less (specifically, 0°C to 5°C).

[0158] Next, a first gas-phase reduction step was carried out. That is, the mixed solution obtained in the first impregnation step was dried under vacuum at 100°C, and then the solvent component was volatilized by maintaining it in a nitrogen atmosphere at 150°C. The obtained solid was subjected to a heat treatment (first gas-phase reduction treatment) at 350°C for 120 minutes in a hydrogen atmosphere (100% by volume of hydrogen gas) to obtain a platinum-supported catalyst.

[0159] Next, the second impregnation step was carried out. Specifically, 2.1 g of the platinum-supported catalyst obtained in the first gas-phase reduction step was mixed with 20 g of an aqueous solution containing cobalt chloride (COCl2), a cobalt precursor, in an amount sufficient to achieve a cobalt concentration of 0.56 wt% (cobalt content: 0.112 g), and the mixture was stirred for 1 hour. The mixture was first maintained under reduced pressure of -0.10 MPa or less (specifically, -0.10 MPa to -0.1013 MPa) for 1 hour, then maintained under increased pressure of 0.15 MPa or more (specifically, 0.15 MPa to 0.20 MPa) for 1 hour, and then stirred and mixed for 18 hours. This second impregnation step was carried out while maintaining the temperature of the mixture at 5°C or less (specifically, 0°C to 5°C).

[0160] Next, a second gas-phase reduction step was carried out. That is, the mixed solution obtained in the second impregnation step was dried under vacuum at 100°C. The obtained solid was subjected to a heat treatment (second gas-phase reduction treatment) in a hydrogen atmosphere (100% hydrogen gas by volume) at 700°C for 60 minutes, and then, while maintaining the atmosphere temperature in the range of 650 to 750°C, the hydrogen atmosphere was replaced with a nitrogen atmosphere (100% nitrogen gas by volume), and a heat treatment (alloying treatment) in the nitrogen atmosphere at 700°C for 120 minutes was carried out to obtain a platinum alloy supported catalyst.

[0161] Next, a post-treatment step was carried out. Specifically, in order to remove excess metal from the platinum alloy-supported catalyst obtained in the second gas-phase reduction step, the platinum alloy-supported catalyst was mixed with a 10% nitric acid solution for 2 hours. The platinum alloy-supported catalyst was then separated from the acid solution by filtration, and the platinum alloy-supported catalyst was further washed with distilled water until the filtrate became neutral. The washed platinum alloy-supported catalyst was dried in a vacuum at 60°C to remove moisture.

[0162] Thereafter, the platinum alloy supported catalyst was subjected to a heat treatment in nitrogen at 300°C to remove nitric acid, and further to a heat treatment in nitrogen at 700°C to reduce and remove platinum oxide. In this way, a metal-supported catalyst was obtained, comprising a carbon support (carbon support C1500-G1700 in Example 1, carbon support C1500-G1800 in Example 3, carbon support C1500-G1900 in Example 4, carbon support C1500-G2000 in Example 5, carbon support C1500-G2100 in Example 6, carbon support C2000 in Example 14, carbon support C1500-G2000 in Example C1, carbon support C1500 in Example C5, carbon support C1500 in Example C7, carbon support C1500-G2200 in Example C8, carbon support C1500-G2400 in Example C8, carbon support KB in Example C9, and carbon support KB-G2000 in Example C10) and platinum and cobalt alloy particles supported on the carbon support.

[0163] In Example 2, a metal-supported catalyst comprising carbon support C1500-G1800 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that in the first impregnation step, 14.3 g of an aqueous solution containing chloroplatinic acid in an amount such that the platinum concentration became 5 wt % (platinum content: 0.71 g) was used, and in the second impregnation step, 20 g of an aqueous solution containing cobalt chloride in an amount such that the cobalt concentration became 0.36 wt % (cobalt content: 0.072 g) was used.

[0164] In Example 7, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that in the second impregnation step, 20 g of an aqueous solution containing cobalt chloride in an amount such that the cobalt concentration was 0.32 wt % (cobalt content: 0.064 g) was used.

[0165] In Example 8, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that the first impregnation step and the second impregnation step were carried out while maintaining the temperature of the mixed solution at 25°C.

[0166] In Example 9, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that the mixed solution was held under reduced pressure and under increased pressure for one hour each, and then the mixed solution was stirred and mixed for 18 hours instead of 66 hours.

[0167] In Example 10, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that 20 g of an aqueous solution containing cobalt chloride in an amount such that the cobalt concentration became 0.23 wt % (cobalt content: 0.045 g) was used in the second impregnation step.

[0168] In Example 11, a metal-supported catalyst comprising carbon support C1500-G2000 and platinum-nickel alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that in the second impregnation step, 20 g of an aqueous solution containing nickel chloride hexahydrate (NiCl 6H O) in an amount such that the nickel concentration was 0.56 wt % (nickel content: 0.111 g) was used instead of the aqueous solution containing cobalt chloride.

[0169] In Example 12, a metal-supported catalyst comprising carbon support C1500-G2000 and alloy particles of platinum, nickel, and manganese supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that in the second impregnation step, instead of the aqueous solution containing cobalt chloride, 20 g of an aqueous solution containing nickel chloride hexahydrate (NiCl 6H O) and manganese chloride tetrahydrate (MnCl 4H O) in amounts such that the nickel concentration was 0.278 wt % (nickel content 0.056 g) and the manganese concentration was 260 wt % (manganese content 0.052 g) was used.

[0170] In Example 13, the first impregnation step was carried out in the same manner as in the above-mentioned Example 1, etc., except that 17.8 g of an aqueous solution containing chloroplatinic acid in an amount such that the platinum concentration was 5 wt % (platinum content: 0.89 g) was used. Thereafter, the first gas-phase reduction step, second impregnation step, and second gas-phase reduction step were carried out in the same manner as in the above-mentioned Example 1, etc.

[0171] Next, a third impregnation step was carried out. 1.99 g of the platinum alloy supported catalyst obtained in the second gas-phase reduction step was mixed with 22.2 g of an aqueous solution containing chloroplatinic acid in an amount sufficient to give a platinum concentration of 1 wt % (platinum content: 0.22 g) by stirring for 1 hour. The mixed solution was first maintained at a reduced pressure of -0.10 MPa or less (specifically, -0.10 MPa to -0.1013 MPa) for 1 hour, then maintained at a pressure of 0.15 MPa or more (specifically, 0.15 MPa to 0.20 MPa) for 1 hour, and then stirred and mixed for 66 hours. This third impregnation step was carried out while maintaining the temperature of the mixed solution at 5°C or less.

[0172] Next, a third gas-phase reduction step was carried out. That is, the mixed solution obtained in the third impregnation step was dried in a vacuum at 100°C and further maintained in nitrogen at 150°C to volatilize the solvent component. The obtained solid was subjected to a heat treatment (gas-phase reduction treatment) at 700°C for 60 minutes in a hydrogen atmosphere (100% by volume of hydrogen gas). Subsequently, while maintaining the atmosphere temperature in the range of 650 to 750°C, the hydrogen atmosphere was replaced with a nitrogen atmosphere (100% by volume of nitrogen gas), and a heat treatment (alloying treatment) was carried out in the nitrogen atmosphere at 700°C for 120 minutes. Thereafter, a post-treatment step was carried out in the same manner as in Example 1 above, to obtain a metal-supported catalyst comprising a carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support.

[0173] In Example 15, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that in the first impregnation step and the second impregnation step, the mixed solution was held at atmospheric pressure for 2 hours instead of being held under reduced pressure for 1 hour and under pressure for 1 hour.

[0174] In Example 16, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that the heating temperature in the hydrogen atmosphere and nitrogen atmosphere in the second gas-phase reduction step was 1000°C instead of 700°C.

[0175] In Example C1, a metal-supported catalyst comprising carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in Example 1 above, except that 9.0 g of an aqueous solution containing chloroplatinic acid in an amount such that the platinum concentration was 5 wt % (platinum content: 0.45 g) was used in the first impregnation step.

[0176] In Example C2, a metal-supported catalyst comprising carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that in the first impregnation step, instead of the aqueous solution containing chloroplatinic acid, 42.2 g of an aqueous solution containing chloroplatinic acid and cobalt chloride in amounts such that the platinum concentration was 5 wt % (platinum content: 1.1 g) and the cobalt concentration was 0.56 wt % (cobalt content: 0.112 g) was used; in the first impregnation step and the second impregnation step, instead of holding the mixed solution under reduced pressure for 1 hour and under pressure for 1 hour, the mixed solution was held at atmospheric pressure for 2 hours; and the second impregnation step and the second gas-phase reduction step were not performed.

[0177] In Example C3, a metal-supported catalyst containing carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in Example 1 above, except that the heating temperature in the hydrogen atmosphere and nitrogen atmosphere in the second gas-phase reduction step was 500°C instead of 700°C.

[0178] In Example C4, catalytic metal particles were supported on a carbon support by the following liquid-phase reduction method. First, a first impregnation step was performed. 1 g of the carbon support and 22.2 g of an aqueous solution containing chloroplatinic acid in an amount sufficient to achieve a platinum concentration of 5 wt % (platinum content: 1.11 g) were mixed and stirred for 1 hour. The mixed solution was first maintained under a reduced pressure of -0.10 MPa or less (specifically, -0.10 MPa to -0.1013 MPa) for 1 hour, then maintained under an increased pressure of 0.15 MPa or more (specifically, 0.15 MPa to 0.20 MPa) for 1 hour, and then stirred and mixed for 66 hours. This first impregnation step was performed while maintaining the temperature of the mixed solution at 5°C or less (specifically, 0°C to 5°C).

[0179] Next, a first liquid-phase reduction step was carried out: Ethylene glycol was added as a reducing agent to the mixed solution obtained in the first impregnation step, and the mixture was kept in air at 80°C for 4 hours to carry out a liquid-phase reduction treatment, thereby obtaining a platinum-supported catalyst.

[0180] Next, a second impregnation step was carried out. Specifically, the mixed solution obtained in the first liquid-phase reduction step was dried in a vacuum at 100°C and then maintained at 150°C in nitrogen to volatilize the solvent component. 2.0 g of the resulting platinum-supported catalyst was mixed with 20 g of an aqueous solution containing cobalt chloride in an amount sufficient to achieve a cobalt concentration of 0.56 wt% (cobalt content: 0.112 g) by stirring for 1 hour. The mixed solution was maintained under a reduced pressure of -0.10 MPa or less (specifically, -0.10 MPa to -0.1013 MPa) for 1 hour, then under an increased pressure of 0.15 MPa or more (specifically, 0.15 MPa to 0.20 MPa) for 1 hour, and then stirred and mixed for 18 hours. This second impregnation step was carried out while maintaining the mixed solution at a temperature of 5°C or less (specifically, 0°C to 5°C).

[0181] Next, a second liquid-phase reduction step was carried out. That is, ethylene glycol was added as a reducing agent to the mixed solution obtained in the second impregnation step, and the mixture was kept in air at 80°C for 4 hours to carry out a liquid-phase reduction treatment.

[0182] Next, an alloying step was carried out. That is, the mixed liquid obtained in the second liquid-phase reduction step was dried in a vacuum at 100°C. The obtained solid was subjected to a heat treatment (alloying treatment) at 700°C for 60 minutes in a hydrogen atmosphere (100% by volume of hydrogen gas). Subsequently, while maintaining the temperature of the atmosphere in the range of 650 to 750°C, the hydrogen atmosphere was replaced with a nitrogen atmosphere (100% by volume of nitrogen gas), and a heat treatment was performed in the nitrogen atmosphere at 700°C for 120 minutes to obtain a platinum alloy supported catalyst.

[0183] Next, a post-treatment step was carried out. Specifically, in order to remove excess metal from the platinum alloy-supported catalyst obtained in the alloying step, the platinum alloy-supported catalyst was mixed with a 10% nitric acid solution for 2 hours. The platinum alloy-supported catalyst was then separated from the acid solution by filtration, and the platinum alloy-supported catalyst was further washed with distilled water until the filtrate became neutral. The washed platinum alloy-supported catalyst was dried in a vacuum at 60°C to remove moisture.

[0184] Thereafter, the platinum alloy-supported catalyst was subjected to a heat treatment in nitrogen at 300°C to remove nitric acid. Further, the platinum alloy-supported catalyst was subjected to a heat treatment in nitrogen at 700°C to reduce and remove platinum oxide. In this way, a metal-supported catalyst was obtained, which included the carbon support C1500-G2000 and platinum-cobalt alloy particles supported on the carbon support.

[0185] In Example C6, a metal-supported catalyst containing carbon support C1500 and platinum-cobalt alloy particles supported on the carbon support was obtained in the same manner as in the above-mentioned Example 1, etc., except that the heating temperature in the hydrogen atmosphere and nitrogen atmosphere in the second gas-phase reduction step was 500°C instead of 700°C.

[0186] [Raman spectroscopy] The metal-supported catalysts were analyzed by Raman spectroscopy. Raman spectra were measured using a HORIBA microscopic laser Raman spectrometer (LabRAM, HORIBA Jobin Yvon). The laser used for the measurements had an excitation wavelength of 532 nm, an output of 50 mW, and was measured through a neutral density filter D3 under the conditions of 90 seconds of exposure x 2 accumulations.

[0187] The Raman spectra were subjected to baseline correction. -1 ) is 600cm -1 Scattering intensity near 2000cm -1 A straight line connecting nearby scattering intensities was determined as the baseline, and baseline correction was performed by subtracting this baseline from each intensity of the scattering spectrum.

[0188] Then the Raman shift is 1340cm -1 Around (specifically, 1320 cm -1 Above, 1360cm -1 The D band with a peak top in the range of 1000 to 15000 was identified. d (D band peak top intensity) -1 )A dFrom the above, the intensity of the D band I d The Raman shift (cm) corresponding to half the intensity of -1 )B d By subtracting the Raman D half-width at half maximum (cm -1 That is, the Raman D half width at half maximum of the metal-supported catalyst was calculated by the following formula: Raman D half width at half maximum (cm -1 )=A d (cm -1 )-B d (cm -1 ).

[0189] Then the Raman shift is 1600cm -1 Around (specifically, 1550 cm -1 More than 1700cm -1 G band with a peak top in the range below 2680 cm -1 around (specifically, 2600 cm -1 More than 2800cm -1 The 2D bands with peak tops in the range of 1000 to 15000 were identified. 2d (Intensity of the peak top of the 2D band) is the intensity of the G band, I g (G band peak top intensity) to obtain the G band intensity I g Intensity I of the 2D band 2d The ratio (Raman 2D / G ratio) of the carbon support was calculated using the following formula: Raman 2D / G ratio = I 2d / I g .

[0190] Here, FIG. 1 shows, as an example of a Raman spectrum, the results of analyzing the Raman spectrum obtained by Raman spectroscopy of the metal-supported catalyst of Example 2. In FIG. 1, the horizontal axis represents the Raman shift (cm -1 ) and the vertical axis indicates the scattering intensity after baseline correction. d is the Raman shift (cm) corresponding to the peak top of the D band -1 ) and B d is the A d D band intensity I at lower wavenumbers dThe Raman shift (cm) corresponding to the Raman spectrum showing half the intensity (height of the peak top of the D band) -1 ) is shown in Fig. 1. The G-band intensity I g (G band peak top height) and 2D band intensity I 2d (height of the peak top of the 2D band) are also shown.

[0191] [Metal content: Inductively coupled plasma atomic emission spectroscopy] The platinum and non-platinum metal (metals other than platinum) contents of the metal-supported catalyst were measured by inductively coupled plasma optical emission spectroscopy (ICP-OES). First, 100 mg of the metal-supported catalyst was heated at 800°C for 3 hours in an air atmosphere to remove non-metallic components (components other than metals) from the metal-supported catalyst.

[0192] The metal-supported catalyst was then immersed in 5 mL of aqua regia and heated at 50°C for 1 hour to dissolve the metals contained in the metal-supported catalyst. Distilled water was then added to dilute the solution to a volume of 50 mL, yielding a metal solution. The platinum and non-platinum metal concentrations of the resulting metal solution were then measured using a sequential plasma emission spectrometer (ICPS-8100, manufactured by Shimadzu Corporation).

[0193] The platinum concentration (mg / mL) and non-platinum metal concentration (mg / mL) of the metal solution were multiplied by the volume of the metal solution (50 mL) to obtain the platinum weight (mg) and non-platinum metal weight (mg) per 100 mg of metal-supported catalyst.

[0194] Furthermore, the platinum content (wt%) and non-platinum metal content (wt%) obtained by ICP-OES were calculated by dividing the platinum weight (mg) and non-platinum metal weight (mg) contained in the metal-supported catalyst by 100 mg, which is the weight of the metal-supported catalyst, and then multiplying this result by 100. The sum of the platinum content (wt%) and non-platinum metal content (wt%) of the metal-supported catalyst was also calculated as the metal content (wt%) of the metal-supported catalyst.

[0195] [Specific surface area and average pore diameter] The specific surface area and average pore diameter of the metal-supported catalyst were measured by nitrogen adsorption using a specific surface area / pore size distribution analyzer (TriStar II 3020, manufactured by Shimadzu Corporation) and the accompanying analysis software (TriStar II 3020).

[0196] First, 0.1 g of the metal-supported catalyst was heated at 100°C for 6.7 × 10 -2 The water adsorbed on the metal-supported catalyst was removed by holding the catalyst at 77 Pa for 3 hours. Next, the change in the amount of nitrogen adsorbed on the metal-supported catalyst with the change in nitrogen gas pressure was measured at a temperature of 77 K, and a nitrogen adsorption isotherm at a temperature of 77 K was obtained.

[0197] The nitrogen adsorption isotherm at 77 K was used to calculate the BET specific surface area (m 2 / g) was obtained. Furthermore, the BET specific surface area (m 2 / g) and the metal content (wt%) of the metal-supported catalyst obtained by ICP-OES described above, the BET specific surface area (m 2 / g-carbon support). That is, the weight ratio of the carbon support contained in the metal-supported catalyst was first calculated using the following formula: Weight ratio of carbon support = 1 - (metal content (wt%) obtained by ICP-OES) / 100. Next, the BET specific surface area (m 2 / g), the BET specific surface area per 1 g of carbon support (m 2 The total pore volume (cm) of the metal-supported catalyst was calculated from the amount of adsorption at a relative pressure P / P of 0.98 in the nitrogen adsorption isotherm at 77 K. 3 / g) was obtained.

[0198] Then, using the analysis software attached to the specific surface area / pore size distribution measurement device, the average pore size (nm) of the metal-supported catalyst was calculated according to the following formula: average pore size (nm) = 4 × {total pore volume (cm 3 / g)×10 21} / {specific surface area(m 2 / g)×10 18}.

[0199] [Alloy composition heterogeneity] The alloy composition heterogeneity was calculated according to the following formula (I) using the measured lattice constant of the platinum alloy contained in the metal-supported catalyst, determined by powder X-ray diffraction (XRD) of the metal-supported catalyst, and the theoretical lattice constant of the platinum alloy contained in the metal-supported catalyst, determined by ICP-OES of the metal-supported catalyst. That is, the alloy composition heterogeneity was calculated by subtracting the value obtained by dividing the theoretical lattice constant by the measured lattice constant from 1, and then multiplying the result by 100. JPEG0007720272000009.jpg12170

[0200] The measured lattice constant of the platinum alloy contained in the metal-supported catalyst was determined using the Bragg equation from the XRD pattern obtained by powder X-ray diffraction of the metal-supported catalyst. Specifically, XRD measurements were performed using an X-ray diffractometer (Rigaku RINT2100 / PC, Rigaku Corporation). The voltage and current applied to the X-ray tube were 50 kV and 300 mA, respectively. The sampling interval was 0.1°, the scanning rate was 1° / min, and the measurement angle range (2θ) was 5 to 90°. CuKα was used as the incident X-ray. The sample thickness was 0.5 mm, and the divergence slit width β was 2 / 3°.

[0201] The lattice spacing was calculated from the peak top position (diffraction angle 2θ) of the diffraction peak corresponding to the (111) plane of the platinum alloy, which appeared in the diffraction angle 2θ range of 39° to 44° in the obtained XRD pattern, using the following Bragg equation: 2d sinθ=nλ, where d is the lattice spacing, θ is the X-ray incident angle, λ is the X-ray incident wavelength, and n is an integer.

[0202] Then, the lattice constant (measured lattice constant) a was calculated using the following relational expression between the lattice spacing and the plane index: d = a / (h 2 +k 2 +l 2 ) 0.5In this relationship between the lattice spacing and the plane index, d is the lattice spacing, a is the lattice constant (measured lattice constant), and h, k, and l are the plane indexes.

[0203] The theoretical lattice constant of the platinum alloy contained in the metal-supported catalyst was calculated from the mole fraction of platinum and non-platinum metals measured by ICP-OES using Vegard's law. Vegard's law is an empirical rule that shows the relationship between the composition of an alloy and its lattice constant, and the lattice constant (theoretical lattice constant) a of the alloy is calculated using the following formula (V): JPEG0007720272000010.jpg13170

[0204] In the above formula (V), a on the left side is the lattice constant (theoretical lattice constant) of the alloy, and N is the mole fraction of each metal (for example, N A , N B and N c are the mole fractions of metal A, metal B, and metal C, respectively, and a on the right side is the lattice constant of each metal (for example, a A , a B and a c are the lattice constants of the metals A, B, and C, respectively. Specifically, for example, when an alloy is composed of two metals, namely, metal A and metal B, the theoretical lattice constant a of the alloy is calculated by the following formula: a=N A a A +N B a B In addition, when an alloy is composed of three metals, namely, metal A, metal B, and metal C, the theoretical lattice constant a of the alloy is calculated by the following formula: a = N A a A +N B a B +N c a c In addition, when an alloy is composed of four or more metals, the right side of the above formula (V) contains the term "N" for the fourth and subsequent metals. X a X " (X indicates the metal type) is added.

[0205] The molar fraction of each metal was determined by measuring the metal content of the metal-supported catalyst using ICP-OES. Specifically, the platinum content (wt%) and the content (wt%) of one or more non-platinum metals obtained by ICP-OES as described above were divided by the atomic weight of each metal species to calculate the molar amount of platinum and each of the one or more non-platinum metals. The molar amount of each metal species was then divided by the sum of the molar amounts of all metal species to calculate the molar fraction of each metal species. The theoretical lattice constant of the platinum alloy was determined by substituting the molar fraction thus determined into the Vegard's law formula.

[0206] [Half-value asymmetry and quarter-value asymmetry] Based on the XRD pattern of the metal-supported catalyst obtained as described above, the half-value asymmetry and the quarter-value asymmetry were calculated by the following formulas (II) and (III), respectively. JPEG0007720272000011.jpg11170JPEG0007720272000012.jpg14170

[0207] The above formulas (II) and (III) will be explained with reference to the typical XRD patterns shown in FIG. 2. As shown in FIG. m The diffraction line has a maximum intensity I in the range of 35° to 44° in the diffraction angle 2θ of the XRD pattern of the metal-supported catalyst (the range of diffraction angle 2θ in which the diffraction peak of the (111) plane of the platinum alloy appears). M is the value of the diffraction angle 2θ (the position of the peak top), and D Lh is the diffraction line with the maximum intensity I when the diffraction angle 2θ is in the range of 35° to 44°. M Half the strength of I h The smallest diffraction angle 2θ among the diffraction angles 2θ that exhibit D Hh is the diffraction line with the maximum intensity I when the diffraction angle 2θ is in the range of 35° to 44°. M Half the strength of I h The largest diffraction angle 2θ among the diffraction angles 2θ that Lq is the diffraction line with the maximum intensity I when the diffraction angle 2θ is in the range of 35° to 44°. M One-fourth the strength of I qThe smallest diffraction angle 2θ among the diffraction angles 2θ that exhibit D Hq is the diffraction line with the maximum intensity I when the diffraction angle 2θ is in the range of 35° to 44°. M One-fourth the strength of I q The largest diffraction angle 2θ among the diffraction angles 2θ at which

[0208] Figures 3A and 3B show the XRD patterns obtained for the metal-supported catalysts of Examples 2 and 6, respectively, and Figures 4A and 4B show the XRD patterns obtained for the metal-supported catalysts of Examples C2 and C4, respectively.

[0209] [Platinum / non-platinum metal molar ratio] The ratio of the molar amount of platinum to the molar amount of non-platinum metals constituting the platinum alloy particles supported on the metal-supported catalyst (Pt / M molar ratio) was calculated by dividing the molar fraction of platinum determined by ICP-OES as described above by the molar fraction of the non-platinum metals.

[0210] [Number-average particle size and volume-average particle size of catalytic metal particles: Powder X-ray diffraction] The number-average particle size (nm) and volume-average particle size (nm) of the catalytic metal particles supported on the carbon support in the metal-supported catalyst were measured by powder X-ray diffraction (XRD). Specifically, a powdered metal-supported catalyst sample was placed in a recess (2 cm × 2 cm × 0.5 mm thick) of a glass sample plate and pressed down with a glass slide. The sample was then uniformly packed into the recess so that its surface coincided with the reference plane. The glass sample plate was then fixed to a wide-angle X-ray diffraction sample stage to maintain the shape of the packed sample.

[0211] Powder X-ray diffraction measurements were then performed using an X-ray diffractometer (Rigaku RINT2100 / PC, Rigaku Corporation). The voltage and current applied to the X-ray tube were 50 kV and 300 mA, respectively. The sampling interval was 0.1°, the scanning speed was 1° / min, and the measurement angle range (2θ) was 5 to 90°. CuKα was used as the incident X-ray. The sample thickness was 0.5 mm, and the divergence slit width β was 2 / 3°.

[0212] The obtained XRD pattern was subjected to peak separation using a Gaussian function as described below, and the crystallite diameter corresponding to each peak obtained by the peak separation was calculated using the Scherrer equation. The number of crystallite diameters obtained was calculated as "peak area ratio / crystallite diameter". 3 The number-average particle size of the catalytic metal particles was calculated by a weighted average using the "peak area ratio" as a weight. On the other hand, the volume-average particle size of the catalytic metal particles was calculated by a weighted average using the volume, i.e., the "peak area ratio" as a weight, of the obtained crystallite size.

[0213] Here, the method for determining the number-average particle diameter (nm) and volume-average particle diameter (nm) will be explained in more detail. For a metal-supported catalyst in which platinum alloy particles are supported as catalytic metal particles, the XRD pattern obtained by powder X-ray diffraction using CuKα radiation shows a (111) diffraction line of the platinum alloy at a diffraction angle (2θ) of around 40° (for example, within a range of 35° to 44°). This diffraction line includes a diffraction line derived from pure platinum, a diffraction line derived from the platinum alloy, and a diffraction line derived from the carbon structure of the carbon support.

[0214] Diffraction lines originating from pure platinum are defined as those having a peak top at a diffraction angle (2θ) of 39.6° or more and less than 39.8°. Diffraction lines originating from platinum alloys are defined as those having a peak top at a diffraction angle (2θ) of 39.9° or more and less than 43.0°. Diffraction lines originating from the carbon structure of the carbon support are defined as those having a peak top at a diffraction angle (2θ) of 43.3° or more and less than 43.7°.

[0215] When a metal-supported catalyst contains multiple types of platinum alloys with different compositions and / or crystal structures, multiple diffraction lines originating from the platinum alloys appear. The diffraction angles at which the peak tops of the diffraction lines originating from the platinum alloys are located are determined by their compositions and crystal structures.

[0216] For example, the composition Pt XThe diffraction lines originating from platinum-cobalt alloys represented by Co (X=1 to 20) are defined as diffraction lines having a peak top at a diffraction angle of 39.9° or more and less than 41.8°. X The diffraction lines originating from platinum-nickel alloys represented by Ni (X=1 to 20) are defined as diffraction lines having a peak top at a diffraction angle of 39.9° or more and less than 42.0°. X The diffraction lines originating from a platinum-nickel-manganese alloy represented by Ni1Mn1 (X=2 to 40) are defined as diffraction lines having a peak top at a diffraction angle of 39.9° or more and less than 41.2°.

[0217] Specifically, for example, a diffraction line derived from a platinum-cobalt alloy with a composition of PtCo is defined as a diffraction line having a peak top at a diffraction angle of 41.4° or more and less than 41.8°. A diffraction line derived from a platinum-cobalt alloy with a composition of PtCo is defined as a diffraction line having a peak top at a diffraction angle of 40.3° or more and less than 41.2°. A diffraction line derived from a platinum-cobalt alloy with a composition of PtCo is defined as a diffraction line having a peak top at a diffraction angle of 39.9° or more and less than 40.3°.

[0218] For example, a diffraction line derived from a platinum-nickel alloy with a composition of PtNi is defined as a diffraction line having a peak top at a diffraction angle of 41.6° or more and less than 42.0°. A diffraction line derived from a platinum-nickel alloy with a composition of PtNi is defined as a diffraction line having a peak top at a diffraction angle of 40.4° or more and less than 41.2°. A diffraction line derived from a platinum-nickel alloy with a composition of PtNi is defined as a diffraction line having a peak top at a diffraction angle of 39.9° or more and less than 40.3°. A diffraction line derived from a platinum-nickel-manganese alloy with a composition of PtNiMn is defined as a diffraction line having a peak top at a diffraction angle of 40.1° or more and less than 40.8°.

[0219] Furthermore, when the metal-supported catalyst contains multiple types of platinum particles that have the same composition and crystal structure but different crystallite sizes, multiple diffraction lines appear that have peak tops at approximately the same diffraction angle and different full widths at half maximum.

[0220] In fact, in the XRD pattern obtained for the metal-supported catalyst, the (111) diffraction line of the platinum alloy appeared at a diffraction angle (2θ) of approximately 40°. Therefore, baseline correction was first performed. That is, the line connecting the diffraction intensity at a diffraction angle (2θ) of 35° to 37° and the diffraction intensity at a diffraction angle (2θ) of 50° to 52° was determined as the baseline, and baseline correction was performed by subtracting this baseline from the intensity of each diffraction line.

[0221] Next, the baseline-corrected diffraction lines were separated into peaks derived from one or more types of pure platinum and / or one or more types of platinum alloys, and a peak derived from carbon. The separation of the diffraction lines was performed by assuming that each of the multiple peaks obtained by the separation was represented by a Gaussian function, and optimizing the intensity of the Gaussian function for each of the multiple peaks, the diffraction angle at the peak top, and the full width at half maximum so that the sum of squares of the residuals obtained by adding up the squares of the differences (residuals) between the intensity of the diffraction line and the sum of the intensities of each of the multiple peaks at each diffraction angle in the XRD pattern was minimized.

[0222] Here, with reference to the XRD pattern obtained by powder XRD measurement of the metal-supported catalyst of Example 2, the peak separation of the (111) diffraction line of a platinum-cobalt alloy having a peak top at a diffraction angle (2θ) of around 40° (within the range of 39° to 44°) will be described.

[0223] In the XRD pattern of the metal-supported catalyst of Example 2, after baseline correction, a diffraction line with a peak top at a diffraction angle (2θ) of 40.5° appeared, as shown in Figure 5A. The central shape of this diffraction line was significantly narrower than the lower shape, and the upper shape was even narrower than the central shape. Therefore, it was thought that at least two diffraction lines overlapped at the peak at a diffraction angle (2θ) of 40.5°: a first PtCo diffraction line with a relatively large full width at half maximum and a second PtCo diffraction line with a different crystallite diameter from the first PtCo and a smaller full width at half maximum. Furthermore, because the metal-supported catalyst contained a carbon support, it was thought that a carbon-derived diffraction line was also present near a diffraction angle (2θ) of 43.5°.

[0224] Therefore, using the peak separation method described above, the diffraction line having a peak top at a diffraction angle (2θ) of 40.5° was separated into three components consisting of a peak derived from the first Pt3Co, a peak derived from the second Pt3Co, and a peak derived from carbon.

[0225] The results of this peak separation into three components are shown in Figure 5B. In Figure 5B, the "baseline corrected" diffraction lines indicate diffraction lines obtained by applying baseline correction to the diffraction lines obtained by XRD measurement, and the "PtCo(1)" peak, the "PtCo(2)" peak, and the "carbon" peak indicate the first PtCo-derived peak, the second PtCo-derived peak, and the carbon-derived peak, respectively, obtained by peak separation of the "baseline corrected" diffraction lines.

[0226] However, as shown in Figure 5B, when the baseline-corrected diffraction line peak separation was performed to match the broadening of the base at diffraction angles (2θ) from around 35° to around 39° and the intensity up to the eighth station of the peak, the sharp angle of the peak top around 40.5° could not be reproduced.

[0227] In this regard, as mentioned above, the diffraction line originating from the platinum-cobalt alloy represented by Pt3Co has a peak top at a diffraction angle of 40.3° or more and less than 41.2°, and therefore it was thought that a third diffraction line of Pt3Co having a peak top at a position around 40.5° was mixed in.

[0228] Therefore, using the peak separation method described above, the diffraction line having a peak top at a diffraction angle (2θ) of 40.5° was separated into four components consisting of a peak derived from the first Pt3Co, a peak derived from the second Pt3Co, a peak derived from the third Pt3Co, and a peak derived from carbon.

[0229] The results of this peak separation into four components are shown in Figure 5C. Figure 5D also shows an enlarged portion of Figure 5C. In Figures 5C and 5D, the "baseline-corrected" diffraction lines indicate diffraction lines obtained by applying baseline correction to the diffraction lines obtained by XRD measurement, and the "PtCo(1)" peak, the "PtCo(2)" peak, the "PtCo(3)" peak, and the "carbon" peak indicate the first PtCo-derived peak, the second PtCo-derived peak, the third PtCo-derived peak, and the carbon-derived peak, respectively, obtained by peak separation of the "baseline-corrected" diffraction lines.

[0230] The peak obtained by adding the peaks of "Pt3Co(1)," "Pt3Co(2)," "Pt3Co(3)," and "carbon" was almost completely consistent with the "baseline corrected" diffraction line, and is therefore not shown in Figures 5C and 5D.

[0231] Thus, the sum of squares of residuals when the peaks were separated into four components was reduced to an extremely small value compared to the sum of squares of residuals when the peaks were separated into three components. Therefore, it was concluded that the metal-supported catalyst of Example 2 supported first Pt3Co particles, second Pt3Co particles, and third Pt3Co particles as platinum-cobalt alloy particles.

[0232] The crystallite diameters of the first Pt3Co particles, the second Pt3Co particles, and the third Pt3Co particles were calculated using the following Scherrer formula: Crystallite diameter (nm) = Kλ / β cos θ, where K is the Scherrer constant (0.94), λ is the wavelength of CuKα radiation (0.15418 nm), β is the full width at half maximum (radian), and θ is the diffraction angle (radian).

[0233] That is, for example, the crystallite diameter of the first Pt3Co particles was calculated by substituting the diffraction angle and full width at half maximum of the "Pt3Co(1)" separated peak in the XRD pattern shown in Figure 5C into the Scherrer equation. As a result, the crystallite diameter of the first Pt3Co particles was calculated to be 2.3 nm, the crystallite diameter of the second Pt3Co particles was calculated to be 5.6 nm, and the crystallite diameter of the third Pt3Co particles was calculated to be 18.8 nm.

[0234] Furthermore, the peak area ratio (%) of each Pt3Co separation peak was calculated by dividing the area of each of the three Pt3Co separation peaks obtained by the above-mentioned peak separation (i.e., the peak area of "Pt3Co(1)," the peak area of "Pt3Co(2)," and the peak area of "Pt3Co(3)") by the sum of the areas of the three Pt3Co separation peaks and multiplying the result by 100. As a result, the peak area ratio of the first Pt3Co particle was calculated to be 56.4%, the peak area ratio of the second Pt3Co particle was calculated to be 42.0%, and the peak area ratio of the third Pt3Co particle was calculated to be 1.6%.

[0235] The volume average particle diameter of the catalytic metal particles was calculated by a weighted average using the peak area ratios as weights. Specifically, the volume average particle diameter of the platinum alloy particles supported on the metal-supported catalyst of Example 2 was calculated to be 4.0 nm using the following formula: Volume average particle diameter (nm) = {(2.3 × 56.4) + (5.6 × 42.0) + (18.8 × 1.6)} / (56.4 + 42.0 + 1.6).

[0236] Furthermore, the ratio of peak area to crystallite diameter 3The number average particle size of the catalytic metal particles was calculated by a weighted average using " as a weight. Specifically, the number average particle size of the Pt3Co particles supported on the metal-supported catalyst of Example 2 was calculated to be 2.5 nm using the following formula: Number average particle size (nm) = {(2.3 × 56.4 / 2.3 3 )+(5.6×42.0 / 5.6 3 )+(18.8×1.6 / 18.8 3 )} / (56.4 / 2.3 3 +42.0 / 5.6 3 +1.6 / 18.8 3 ).

[0237] Figure 6A shows the results of peak separation in the XRD pattern obtained for the metal-supported catalyst of Example C2. Figure 6B shows an enlarged view of a portion of the XRD pattern shown in Figure 6A. As shown in Figures 6A and 6B, the baseline-corrected diffraction lines were separated into one peak derived from pure platinum, one peak derived from the platinum-cobalt alloy, and a peak derived from carbon.

[0238] In the XRD pattern obtained by powder XRD measurement of the metal-supported catalyst of Example C2, after baseline correction, diffraction lines with peak tops at diffraction angles (2θ) of 39.7° and 41.0° appeared. The shape of the central portion of each peak diffraction line was significantly narrower than the shape of the lower portion, and the shape of the upper portion was even narrower than the shape of the central portion. Therefore, it was thought that three diffraction lines overlapped at the 39.7° peak: a diffraction line of a first Pt with a relatively large full width at half maximum, a diffraction line of a second Pt with a different crystallite diameter from the first Pt and a smaller full width at half maximum, and a diffraction line of a third Pt with a different crystallite diameter from the first and second Pt and an even smaller full width at half maximum. Furthermore, it was considered that three diffraction lines overlapped at the peak at 41.0°: a diffraction line of the first Pt3Co with a relatively large full width at half maximum, a diffraction line of the second Pt3Co with a different crystallite diameter from the first PtCo and a smaller full width at half maximum, and a diffraction line of the third Pt3Co with a different crystallite diameter from the first and second Pt3Co and an even smaller full width at half maximum. Furthermore, since the metal-supported catalyst contains a carbon support, it was considered that there was a diffraction line derived from carbon at a diffraction angle (2θ) of around 43.5°.

[0239] Therefore, as shown in Figures 6A and 6B, by the above-mentioned peak separation method, the diffraction line having a peak top at a diffraction angle (2θ) of 39.7° and the diffraction line having a peak top at a diffraction angle (2θ) of 40.1° were separated into seven components consisting of a peak derived from the first Pt, a peak derived from the second Pt, a peak derived from the third Pt, a peak derived from the first PtCo, a peak derived from the second PtCo, a peak derived from the third PtCo, and a peak derived from carbon.

[0240] 6A and 6B, the "baseline corrected" diffraction lines indicate diffraction lines obtained by applying baseline correction to the diffraction lines obtained by XRD measurement, and the "Pt(1)" peak, the "Pt(2)" peak, the "Pt(3)" peak, the "PtCo(1)" peak, the "PtCo(2)" peak, the "PtCo(3)" peak, and the "carbon" peak indicate the first Pt-derived peak, the second Pt-derived peak, the third Pt-derived peak, the first PtCo-derived peak, the second PtCo-derived peak, the third PtCo-derived peak, and the carbon-derived peak, respectively, obtained by peak separation of the "baseline corrected" diffraction lines.

[0241] The crystallite diameters of the first Pt particles, second Pt particles, and third Pt particles, as well as the first Pt3Co particles, second Pt3Co particles, and third Pt3Co particles, were calculated using the Scherrer formula. For example, the crystallite diameter of the first Pt particles was calculated by substituting the diffraction angle and full width at half maximum of the "Pt(1)" peak in the XRD patterns shown in Figures 6A and 6B into the Scherrer formula. As a result, the crystallite diameter of the first Pt particles was calculated to be 3.7 nm, the crystallite diameter of the second Pt particles was calculated to be 8.1 nm, the crystallite diameter of the third Pt particles was calculated to be 18.7 nm, the crystallite diameter of the first Pt3Co particles was calculated to be 5.7 nm, the crystallite diameter of the second Pt3Co particles was calculated to be 18.6 nm, and the crystallite diameter of the third Pt3Co particles was calculated to be 29.5 nm.

[0242] In addition, the area of each of the separated peaks of the three Pt and three Pt3Co particles obtained by the above-mentioned peak separation (i.e., the peak area of "Pt(1)," the peak area of "Pt(2)," and the peak area of "Pt(3)," the peak area of "Pt3Co(1)," the peak area of "Pt3Co(2)," and the peak area of "Pt3Co(3)") was divided by the sum of the areas of the separated peaks of the three Pt and three Pt3Co particles, respectively, and multiplied by 100 to calculate the peak area percentage (%) of each of the Pt and Pt3Co particles. As a result, the peak area ratio of the first Pt particles was calculated to be 17.3%, the peak area ratio of the second Pt particles was calculated to be 44.4%, the peak area ratio of the third Pt particles was calculated to be 17.7%, the peak area ratio of the first Pt3Co particles was calculated to be 8.7%, the peak area ratio of the second Pt3Co particles was calculated to be 5.8%, and the peak area ratio of the third Pt3Co particles was calculated to be 6.1%.

[0243] The volume average particle size of the catalytic metal particles was calculated by a weighted average using the peak area ratios as weights. Specifically, the volume average particle size of the platinum alloy particles supported on the metal-supported catalyst of Example C2 was calculated to be 11.0 nm using the following formula: Volume average particle size (nm) = {(3.7 × 17.3) + (8.1 × 44.4) + (18.7 × 17.7) + (5.7 × 8.7) + (18.6 × 5.8) + (29.5 × 6.1)} / (17.3 + 44.4 + 17.7 + 8.7 + 5.8 + 6.1).

[0244] Furthermore, the ratio of peak area to crystallite diameter 3 The number average particle size of the catalytic metal particles was calculated by a weighted average using " as a weight. Specifically, the number average particle size of the Pt3Co particles supported on the metal-supported catalyst of Example C2 was calculated to be 4.9 nm using the following formula: Number average particle size (nm) = {(3.7 × 17.3 / 3.7 3 )+(8.1×44.4 / 8.1 3 )+(18.7×17.7 / 18.7 3 )+(5.7×8.7 / 5.7 3 )+(18.6×5.8 / 18.6 3)+(29.5×6.1 / 29.5 3 )} / (17.3 / 3.7 3 +44.4 / 8.1 3 +17.7 / 18.7 3 +8.7 / 5.7 3 +5.8 / 18.6 3 +6.1 / 29.5 3 ).

[0245] [ECSA sweep speed dependence] The electrochemically effective specific surface area (ECSA) (m 2 / g‐Pt) was evaluated by the rotating ring‐disk electrode method using a rotating ring‐disk electrode apparatus (RRDE‐3A rotating ring‐disk electrode apparatus ver. 1.2, manufactured by BAS Co., Ltd.) and a dual electrochemical analyzer (CHI700C, manufactured by ALS Co., Ltd.).

[0246] That is, first, a three-electrode rotating ring-disk electrode device having a working electrode containing a metal-supported catalyst was fabricated. Specifically, 5 mg of the metal-supported catalyst, 50 μL of 5% Nafion (registered trademark) (manufactured by Sigma-Aldrich, Nafion perfluorinated ion exchange resin, 5% solution (product number: 510211)), 400 μL of water, and 100 μL of isopropyl alcohol were mixed to prepare a slurry. Next, this slurry was subjected to ultrasonic treatment for 10 minutes, and then to homogenization for 2 minutes. The obtained slurry was then subjected to a 10-minute ultrasonic treatment with a metal-supported catalyst coating amount of 0.1 mg / cm. 2 The solution was applied to a working electrode (RRDE-3A ring-disk electrode, platinum ring-gold disk electrode, disk diameter 4 mm, manufactured by BAS Inc.) so that the solution satisfies the above formula, and then dried to prepare a working electrode supported with the metal-supported catalyst.

[0247] A platinum electrode (23 cm Pt counter electrode, manufactured by BAS Co., Ltd.) was used as the counter electrode, and a reversible hydrogen electrode (RHE) (reservoir-type reversible hydrogen electrode, manufactured by EC Frontier Co., Ltd.) was used as the reference electrode. Thus, a rotating ring-disk electrode device was obtained, which had a working electrode containing a metal-supported catalyst, a platinum electrode as the counter electrode, and a reversible hydrogen electrode (RHE) as the reference electrode. A 0.1 M aqueous solution of perchloric acid was used as the electrolyte.

[0248] The ECSA was measured using the rotating ring-disk electrode apparatus described above. Specifically, cyclic voltammetry (CV) was performed in a nitrogen atmosphere using a three-electrode rotating ring-disk electrode apparatus having a working electrode containing a metal-supported catalyst.

[0249] For CV, oxygen was removed from the electrolyte by bubbling nitrogen for 10 min, and then the potential was swept from 0.0 V (vs. NHE) to 0.94 V (vs. NHE) at a sweep rate of 10 mV / sec. The current density was recorded as a function of potential.

[0250] From the cyclic voltammogram thus obtained, ECSA@10 mV (m 2 Specifically, in the cyclic voltammogram of the third cycle, the hydrogen adsorption charge (Q Hupd )(mC / cm 2 ) to obtain the area converted electrical charge (210 μC / cm 2 ) and platinum coating amount (L Pt )(mg-Pt / cm 2 ) and calculated ECSA according to the following formula (VI). JPEG0007720272000013.jpg14170

[0251] Similarly, ECSA@1000mV(m) at a sweep rate of 1000mV / sec 2The ECSA sweep rate dependence (%) of the metal-supported catalyst was calculated using the ECSA@10 mV and ECSA@1000 mV obtained in this way according to the following formula (IV): ECSA@1000 mV was divided by ECSA@10 mV, the value was subtracted from 1, and the result was multiplied by 100 to obtain the ECSA sweep rate dependence (%). JPEG0007720272000014.jpg19170

[0252] Figure 7 shows the results of evaluating the ECSA sweep rate dependency using the metal-supported catalyst of Example 5 and the metal-supported catalyst of Example C4. In Figure 7, the horizontal axis represents the sweep rate (mV / sec), and the vertical axis represents the ECSA retention rate (%). The ECSA retention rate was calculated by dividing the ECSA at each sweep rate by the ECSA @ 10 mV and multiplying the result by 100. In other words, the value obtained by subtracting the ECSA retention rate (%) at a sweep rate of 1000 mV / sec on the horizontal axis from 100 corresponds to the ECSA sweep rate dependency (%) described above.

[0253] As shown in Figure 7, when the metal-supported catalyst of Example C4 was used, the decrease in ECSA due to an increase in the sweep rate was smaller than when the metal-supported catalyst of Example 5 was used. Therefore, it was thought that in the metal-supported catalyst of Example C4, more catalytic metal particles were supported outside the pores of the carbon support than in the metal-supported catalyst of Example 5. In other words, since the metal-supported catalyst of Example C4 was produced by supporting catalytic metal particles on a carbon support by a liquid-phase reduction method, it was thought that the catalytic metal particles were preferentially supported on the outer surface of the carbon support.

[0254] [Performance evaluation of batteries with electrodes containing metal-supported catalysts] The performance of a fuel cell having a cathode containing a metal-supported catalyst was evaluated. Specifically, a cell cathode was fabricated with a catalyst layer containing the metal-supported catalyst. Specifically, an electrolyte solution was prepared by adding 0.25 g of the metal-supported catalyst to the carbon support in an amount such that the weight ratio of the electrolyte to the carbon support was 1.1 (equivalent mass EW = 820), followed by 2 g each of distilled water and 1-propanol. This electrolyte solution was placed in a pot with 25 g of balls and mixed in a ball mill at 200 rpm for 50 minutes to obtain a slurry-like catalyst layer composition containing the uniformly dispersed metal-supported catalyst.

[0255] The resulting slurry composition for catalyst layer was applied to a gas diffusion layer ("29BC", manufactured by SGL Carbon Co., Ltd.) (2.3 cm x 2.3 cm) with an area of 5 cm 2 The platinum content per unit area of the battery electrode is 0.2 (mg-Pt / cm 2 ) and dried to form a catalyst layer on the gas diffusion layer. In this way, a battery electrode having a catalyst layer containing a metal-supported catalyst formed thereon was obtained.

[0256] Next, a fuel cell including a cell electrode on which a catalyst layer containing a metal-supported catalyst was formed was manufactured. That is, the cell electrode including the catalyst layer (cathode catalyst layer) manufactured as described above was used as the positive electrode.

[0257] On the other hand, the negative electrode was prepared as follows. 0.5 g of a commercially available platinum-supported catalyst (Pt / C) (UNPC40-II, manufactured by Ishifuku Metal Industries Co., Ltd.) containing platinum particles supported on a carbon support, 10 g of 5% Nafion (registered trademark), 2 g of distilled water, and 25 g of balls were placed in a pot and mixed in a ball mill at 200 rpm for 50 minutes to prepare a Pt / C composition slurry. This Pt / C composition slurry was applied to a gas diffusion layer (5 cm 2 ) with a platinum content per unit area of 0.1 (mg-Pt / cm 2 ) was used to prepare a negative electrode including a catalyst layer (negative electrode catalyst layer) formed from the Pt / C composition in the same manner as the positive electrode.

[0258] A solid polymer electrolyte membrane (NAFION (registered trademark) 211 manufactured by DuPont) was then placed between the positive electrode catalyst layer and the negative electrode catalyst layer, and these were pressure-bonded at 150°C and 1 MPa for 3 minutes to produce an MEA. A pair of gaskets was attached to this MEA, which was then sandwiched between a pair of separators to produce a single fuel cell. The single cell produced as described above was then installed in an automatic fuel cell evaluation system (manufactured by Toyo Corporation), and first a power generation test was performed, followed by a durability test.

[0259] The power generation test was carried out by supplying saturated humidified air (oxygen) to the positive electrode side at 2.5 L / min (relative humidity 100%) with a back pressure of 150 kPa and saturated humidified hydrogen to the negative electrode side at 1.0 L / min (relative humidity 100%). The cell temperature was set to 75°C and the open circuit voltage was measured for 5 minutes. After that, the cell current density was increased to 4.0 A / cm. 2 to 0 A / cm 2 The cell voltage was measured while maintaining each current density for 3 minutes.

[0260] And the output characteristics are current density 2.5A / cm 2 The voltage (mV) at a current density of 0.2 A / cm was measured as the catalytic activity. 2 The voltage (mV) at the start of the start / stop test was measured at a current density of 1.0 A / cm. 2 The voltage (mV) at

[0261] Next, a start-stop test was performed by setting the cell temperature to 80°C, supplying saturated humidified nitrogen to both sides of the single cell at 1.0 L / min (relative humidity 100%) with a back pressure of 35 kPa, and supplying saturated humidified hydrogen to the anode side at 1.0 mL / min (relative humidity 100%), and repeating a triangular wave cycle of scanning the potential from 1.0 V to 1.5 V at a sweep rate of 500 mV / sec.

[0262] After repeating the above triangular wave cycle 1000 times, a power generation test was conducted again, and the power consumption was 1.0 A / cm after the start / stop test. 2The voltage (mV) at 1.0 A / cm was measured as the initial performance in the power generation test before the start-stop test. 2 From the voltage (mV) at 1.0A / cm2 measured in the power generation test after the start-stop test, 2 The voltage loss (mV) obtained by subtracting the voltage (mV) at 1000 cycles (the voltage (mV) after 1000 cycles) was used as an index of durability in the first start-stop test.

[0263] A load change test was also carried out. As in the start-stop test described above, the voltage at the start of the load change test was set to a current density of 1.0 A / cm. 2 The voltage (mV) at the time of the test was recorded. The cell temperature was then set to 75°C, and saturated humidified nitrogen was supplied to both sides of the single cell at 0.5 L / min (relative humidity 100%) under a back pressure of 150 kPa. Saturated humidified hydrogen was supplied to the anode side at 0.5 mL / min (relative humidity 100%). A load change test was performed by repeating a square wave cycle in which the potential was first held at 0.6 V for 10 seconds and then at 0.95 V for 10 seconds.

[0264] After repeating the above square wave cycle 10,000 times, the power generation test was conducted again, and the current density after the load fluctuation test was 1.0 A / cm 2 The voltage (mV) at 1.0 A / cm was measured as the initial performance in the power generation test before the load change test. 2 From the voltage (mV) at 1.0A / cm2 measured in the power generation test after the load change test, 2 The voltage loss (mV) obtained by subtracting the voltage (mV) at 10,000 cycles (voltage (mV) after 10,000 cycles) was used as an index of durability in the load variation test.

[0265] [Evaluation of ionic resistance] For impedance measurements, the cell temperature was set to 80°C, saturated humidified nitrogen was supplied to both sides of the single cell at 0.5 L / min (relative humidity 100%) under a back pressure of 35 kPa, and saturated humidified hydrogen was supplied to the anode side at 0.5 mL / min (relative humidity 100%). The open circuit voltage was measured for 10 minutes. Then, measurements were performed using an electrochemical measurement system (VSP-300, BioLogic) with an applied voltage of 450 mV, a measurement frequency of 20 kHz to 50 mHz, and an amplitude voltage of ±10 mV.

[0266] The Nyquist plot of the actual measured values was fitted using ZView equivalent circuit analysis software (Scribner Associates) to obtain the ionic resistance R i asked for.

[0267] The state of the electrodes under the above measurement conditions can be modeled by the equivalent circuit shown in Figure 8A. In this equivalent circuit, L is the inductance due to wiring, etc., and R c is the resistance of the electrolyte membrane and electrode materials, and R sh is the short-circuit resistance and W DeLevie is the Warburg impedance. Then the Warburg impedance Z w is represented by the following formula (VII). JPEG0007720272000015.jpg14170

[0268] In the above formula (VII), T is a time constant, and R i and C dl It is defined as the product of R i is the ionic resistance (mΩ cm 2 ) and C dl is the electric double layer capacitance (F). ω is the frequency (Hz). j is the imaginary unit.

[0269] By fitting the Nyquist plot of the actual measured values using the equivalent circuit shown in Figure 8A, R iwas calculated (Reference: Journal of The Electrochemical Society, 157 (3) B425-B436 (2010)). i This is mainly due to the ionic resistance of the catalyst layer, which is thought to be affected by the thickness of the catalyst layer, the hydrophilicity of the catalyst layer, and the degree of degradation of the ionomer.

[0270] FIG. 8B shows the measured values and fitting results of the Nyquist plot obtained for Example 3. As a result of the fitting, the ionic resistance R i is 54 mΩ·cm 2 It was.

[0271] [result] FIG. 9A shows the production conditions for the metal-supported catalysts of Examples 1 to 16 and Examples C1 to C10, and the results of evaluating the characteristics of fuel cells containing the metal-supported catalysts.

[0272] In the start-stop test, as described above, the durability test was performed at a relatively high potential of 1.0 V to 1.5 V. In this potential range, for example, deterioration due to oxidation of the carbon support is likely to progress. Therefore, the smaller the voltage loss in the start-stop test, the higher the durability of the metal-supported catalyst.

[0273] 9A, the durability of the metal-supported catalysts of Examples 1 to 16 was superior to that of Examples C5, C6, and C9, and was comparable to that of Examples C1 to C4, C7, C8, and C10. Furthermore, in the start-stop test, the durability of the metal-supported catalysts of Examples 2 to 16 was superior to that of Example 1, the durability of the metal-supported catalysts of Examples 4 to 16 was superior to that of Examples 2 and 3, and the durability of the metal-supported catalysts of Examples 4 to 8, 10 to 13, 15, and 16 was superior to that of Examples 9 and 14.

[0274] In the load variation test, as described above, the durability test was performed at relatively low potentials of 0.6 V and 0.95 V. In the above potential range, for example, deterioration (e.g., aggregation and / or dissolution) of catalytic metal particles supported on a carbon support is likely to progress. Therefore, the smaller the voltage loss in the load variation test, the higher the durability of the metal-supported catalyst.

[0275] 9A, the durability of the metal-supported catalysts of Examples 1 to 16 was superior to that of Examples C3, C4, C8, and C9, and was comparable to that of Examples C1, C2, C5 to C7, and C10. Furthermore, in the load fluctuation test, the durability of the metal-supported catalysts of Examples 1 to 5, 7, 9 to 13, 15, and 16 was superior to that of Examples 6, 8, and 14.

[0276] Current density of 2.5A / cm showing the power output characteristics of the metal-supported catalyst 2 The larger the voltage (mV) at 2.0 A / cm, the better the output characteristics of the metal-supported catalyst. 2 In the above-mentioned high current density region, a large amount of water is produced, filling the pores of the carbon support with produced water and inhibiting material transport, which tends to result in a decrease in voltage as a battery performance factor.

[0277] 9A, the output characteristics of the metal-supported catalysts of Examples 1 to 16 were superior to those of Examples C8 to C10 and comparable to those of Examples C1 to C7. The output characteristics of Examples 1 to 8 and 10 to 13 were superior to those of Examples 9 and 14 to 16, and the output characteristics of Examples 1 to 5, 7 and 10 to 13 were superior to those of Examples 6 and 8.

[0278] Current density of 0.2 A / cm indicates catalytic activity of metal-supported catalysts 2 The higher the voltage (mV) at 0.2 A / cm, the better the catalytic activity of the metal-supported catalyst. That is, the overvoltage of a fuel cell is classified into activation overvoltage, resistance overvoltage, and diffusion overvoltage. 2 In this case, the influence of the resistance overpotential and the diffusion overpotential is small, so it is suitable for evaluating catalytic activity.

[0279] 9A, the catalytic activities of the metal-supported catalysts of Examples 1 to 16 were superior to those of Examples C7 to C10 and comparable to those of Examples C1 to C6. In addition, the catalytic activities of Examples 1 to 7 and 11 to 13 were superior to those of Examples 8 to 10 and 14 to 16.

[0280] The smaller the ionic resistance, the higher the proton conductivity of the catalyst layer. The ionic resistance is thought to be affected by, for example, the thickness of the catalyst layer, the hydrophilicity of the catalyst layer, and the degree of deterioration of the ionomer. In a catalyst layer containing a metal-supported catalyst, a small ionic resistance is preferred.

[0281] 9A, the ionic resistance of the metal-supported catalysts of Examples 1 to 16 was smaller than that of Examples C1 to C3 and similar to that of Examples C4 to C10. In addition, the ionic resistance of Examples 1, 2, 5 to 13, 15, and 16 was smaller than that of Examples 3, 4, and 14.

[0282] 9B shows the results of evaluating the properties of the metal-supported catalysts of each example. The Raman 2D / G ratios of the metal-supported catalysts of Examples 1 to 16 were higher than those of Examples C5 and C6, comparable to those of Examples C1 to C4 and C8, and lower than those of Example C8. The metal-supported catalysts of Examples 2 to 16 also had a higher Raman 2D / G ratio than that of Example 1, and the metal-supported catalysts of Examples 4 to 13, 15, and 16 also had a higher Raman 2D / G ratio than those of Examples 2 and 3. The metal-supported catalysts of Examples 1 to 13, 15, and 16 also had a lower Raman 2D / G ratio than that of Example 14.

[0283] The Raman D half width at half maximum of the metal-supported catalysts of Examples 1 to 16 was larger than that of Examples C7, C8, and C10, comparable to that of Examples C1 to C4, and smaller than that of Examples C5, C6, and C9. The Raman D half width at half maximum of the metal-supported catalysts of Examples 2 to 16 was smaller than that of Example 1, and the Raman D half width at half maximum of the metal-supported catalysts of Examples 4 to 16 was smaller than that of Examples 2 and 3. The Raman D half width at half maximum of the metal-supported catalysts of Examples 1 to 5, 7 to 13, 15, and 16 was larger than that of Examples 6 and 14.

[0284] The average pore diameter of the metal-supported catalysts of Examples 1 to 16 was larger than that of Examples C5 and C6, comparable to that of Examples C1 to C4, C7 and C9, and smaller than that of Examples C8 and C10. The average pore diameter of the metal-supported catalysts of Examples 1 to 13, 15 and 16 was smaller than that of Example 14, and the average pore diameter of the metal-supported catalysts of Examples 1 to 5, 7 to 13, 15 and 16 was smaller than that of Example 6.

[0285] The BET specific surface areas of the metal-supported catalysts of Examples 1 to 16 were larger than those of Examples C7, C8, and C10, comparable to those of Examples C1 to C4, and C9, and smaller than those of Examples C5 and C6. The metal-supported catalysts of Examples 1 to 5, 7 to 13, 15, and 16 also had larger BET specific surface areas than those of Examples 6 and 14.

[0286] The platinum contents of the metal-supported catalysts of Examples 1 to 16 were higher than that of Example C1 and similar to those of Examples C2 to C10. In addition, the platinum contents of the metal-supported catalysts of Examples 1 and 3 to 16 were higher than that of Example 2.

[0287] Regarding the platinum / non-platinum metal (Pt / M) molar ratio, the metal-supported catalysts of Examples 1 to 16 had a platinum / non-platinum metal molar ratio similar to that of Examples C1 to C10. In addition, the metal-supported catalysts of Examples 1, 3 to 9, and 11 to 16 had a platinum content lower than that of Examples 2 and 10.

[0288] The alloy heterogeneity of the metal-supported catalysts of Examples 1 to 16 was comparable to that of Examples C1, C5, and C7 to C9, but smaller than that of Examples C2 to C4, C6, and C10. In addition, the metal-supported catalysts of Examples 1 to 8 and 10 to 16 had smaller alloy heterogeneity than that of Example 9.

[0289] The half-value asymmetry of the metal-supported catalysts of Examples 1 to 16 was comparable to that of Examples C1 to C3, C5, C7, and C9, and smaller than that of Examples C4, C6, C8, and C10. The metal-supported catalysts of Examples 1 to 8 and 10 to 16 had a smaller half-value asymmetry than that of Example 9, and the metal-supported catalysts of Examples 1 to 7, 10 to 13, and 16 had a smaller half-value asymmetry than that of Examples 8, 14, and 15.

[0290] The metal-supported catalysts of Examples 1 to 16 had a quarter-value asymmetry comparable to that of Examples C1, C5 to C7, C9, and C10, but smaller than that of Examples C2 to C4 and C8. The metal-supported catalysts of Examples 1 to 5 and 7 to 16 also had a quarter-value asymmetry smaller than that of Example 6.

[0291] Regarding the number average particle diameter of the catalytic metal particles, the metal-supported catalysts of Examples 1 to 16 had number average particle diameters comparable to those of Examples C1 to C10. The metal-supported catalysts of Examples 1 to 14 had number average particle diameters smaller than those of Examples 15 and 16, and the metal-supported catalysts of Examples 1 to 7 and 10 to 13 had number average particle diameters smaller than those of Examples 8, 9 and 14.

[0292] The volume average particle diameter of the catalytic metal particles of the metal-supported catalysts of Examples 1 to 16 was similar to that of Examples C1 to C3 and C5 to C9, but smaller than that of Examples C4 and C10. The metal-supported catalysts of Examples 1 to 14 had a smaller volume average particle diameter than that of Examples 15 and 16, and the metal-supported catalysts of Examples 1 to 7 and 10 to 13 had a smaller volume average particle diameter than that of Examples 8, 9, and 14.

[0293] Regarding the ECSA sweep rate dependence, the metal-supported catalysts of Examples 1 to 16 had a higher ECSA sweep rate dependence than those of Examples C8 and C10, and were comparable to those of Examples C1 to C7 and C9. In addition, the metal-supported catalysts of Examples 1 to 15 had a higher ECSA sweep rate dependence than that of Example 16, and the metal-supported catalysts of Examples 1, 3 to 7 and 10 to 13 had a higher ECSA sweep rate dependence than those of Examples 2, 8, 9, 14 and 15.

Claims

1. a carbon support; catalytic metal particles containing a precious metal alloy supported on the carbon support; A metal supported catalyst comprising: The weight ratio of the noble metal to the weight of the metal-supported catalyst is 35% by weight or more, BET specific surface area is 350 (m ２ / g-carbon support) or more, The following characteristics (a1) and / or (a2): (a1) In the Raman spectrum obtained by Raman spectroscopy using an excitation wavelength of 532 nm, a Raman shift of 1600 cm －１ Raman shift of the G band intensity with a peak top near 2680 cm －１ The ratio of the intensities of 2D bands having peak tops nearby is 0.20 or more and 1.00 or less; (a2) In the Raman spectrum obtained by Raman spectroscopy using an excitation wavelength of 532 nm, a Raman shift of 1340 cm －１ The half width at half maximum of the D band having a peak top in the vicinity is 41.0 cm －１ below; and, The following characteristics (b1) and / or (b2): (b1) the alloy composition non-uniformity calculated by the following formula (I) is 0.55 or less; (In the above formula (I), the theoretical lattice constant and the measured lattice constant are the theoretical lattice constant and the measured lattice constant of the noble metal alloy, respectively.) (b2) the half-value asymmetry and quarter-value asymmetry calculated by the following formulas (II) and (III), respectively, are both 0.55 or less; (In the above formula (II) and formula (III), D ｍ is the value of the diffraction angle 2θ at which the diffraction line shows the maximum intensity in the range of diffraction angles 2θ at which the diffraction peak of the (111) plane of the precious metal alloy appears in the X-ray diffraction pattern obtained by powder X-ray diffraction, and D Ｌｈ is the smallest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows half the maximum intensity in the above range, and D Ｈｈ is the largest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows half the maximum intensity in the above range, and D Ｌｑ is the smallest diffraction angle 2θ value among the diffraction angles 2θ at which the diffraction line shows an intensity that is one-fourth of the maximum intensity in the above range, and D Ｈｑ is the largest value of the diffraction angle 2θ among the diffraction angles 2θ at which the diffraction line shows an intensity that is one-fourth of the maximum intensity within the above range.) A metal-supported catalyst for a cathode of a fuel cell or air cell, comprising:

2. A carbon support; catalytic metal particles containing a precious metal alloy supported on the carbon support; A metal supported catalyst comprising: The weight ratio of the noble metal to the weight of the metal-supported catalyst is 35% by weight or more, The BET specific surface area is 350 (m 2 / g-carbon support) or more; The following characteristics (a1) and / or (a2): (a1) In a Raman spectrum obtained by Raman spectroscopy using an excitation wavelength of 532 nm, the ratio of the intensity of the 2D band having a peak top at a Raman shift of about 2680 cm −1 to the intensity of the G band having a peak top at a Raman shift of about 1600 cm −1 is 0.20 or more and 1.00 or less; (a2) In a Raman spectrum obtained by Raman spectroscopy using an excitation wavelength of 532 nm, the half width at half maximum of the D band having a peak top at a Raman shift of about 1340 cm −1 is 41.0 cm −1 or less; and, The following characteristics (b1) and / or (b2): (b1) the alloy composition non-uniformity calculated by the following formula (I) is 0.55 or less; (In the above formula (I), the theoretical lattice constant and the measured lattice constant are the theoretical lattice constant and the measured lattice constant of the noble metal alloy, respectively.) (b2) the half-value asymmetry and quarter-value asymmetry calculated by the following formulas (II) and (III), respectively, are both 0.55 or less; (In the above formulas (II) and (III), D m is the value of the diffraction angle 2θ at which the diffraction line shows the maximum intensity within the range of diffraction angles 2θ at which the diffraction peak of the (111) plane of the precious metal alloy appears in an X-ray diffraction pattern obtained by powder X-ray diffraction; D Lh is the smallest value of the diffraction angle 2θ within said range at which the diffraction line shows an intensity of half of the maximum intensity; D Hh is the largest value of the diffraction angle 2θ within said range at which the diffraction line shows an intensity of half of the maximum intensity; D Lq is the smallest value of the diffraction angle 2θ within said range at which the diffraction line shows an intensity of one-fourth of the maximum intensity; and D Hq is the largest value of the diffraction angle 2θ within said range at which the diffraction line shows an intensity of one-fourth of the maximum intensity.) A metal-supported catalyst for oxygen reduction reaction comprising:

3. Having the characteristic (a1), The metal-supported catalyst according to claim 1 or 2.

4. Having the characteristic (a2), The metal-supported catalyst according to any one of claims 1 to 3.

5. Having the characteristic (b1), The metal-supported catalyst according to any one of claims 1 to 4.

6. Having the characteristic (b2), The metal-supported catalyst according to any one of claims 1 to 5.

7. The average pore diameter is 8.0 nm or less. The metal-supported catalyst according to any one of claims 1 to 6.

8. the molar ratio of the noble metal to the non-noble metal is 1.0 or greater; The metal-supported catalyst according to any one of claims 1 to 7.

9. The number average particle diameter of the catalytic metal particles is 8.0 nm or less. The metal-supported catalyst according to any one of claims 1 to 8.

10. The volume average particle diameter of the catalytic metal particles is 8.0 nm or less. The metal-supported catalyst according to any one of claims 1 to 9.

11. the sweep rate dependency of the electrochemically effective specific surface area (ECSA) of the noble metal contained in the metal-supported catalyst, calculated by the following formula (IV), is 60% or more; (In the above formula (IV), "ECSA@1000 mV" and "ECSA@10 mV" are the electrochemically effective specific surface areas (m) per gram of the noble metal contained in the metal-supported catalyst, which are obtained by cyclic voltammetry using a rotating ring-disk electrode apparatus having a working electrode on which the metal-supported catalyst is supported, with potential sweep at a sweep rate of 1000 mV / sec and potential sweep at a sweep rate of 10 mV / sec, respectively. ２ / g-precious metal). The metal supported catalyst according to any one of claims 1 to 10.

12. The metal-supported catalyst according to any one of claims 1 to 11, Cathode of fuel cell or air battery.

13. Comprising the cathode of claim 12 Fuel cells or air batteries.

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