Carbon material for catalyst support of polymer electrolyte fuel cell, catalyst layer for polymer electrolyte fuel cell, and fuel cell

Abstract

A carbon material for a catalyst carrier of a solid polymer fuel cell comprises porous activated carbon black satisfying requirements (A) to (C). (A) The BET specific surface area is 350 m2 / g to 800 m2 / g. (B) The value (VD5-20 / VA20) obtained by dividing the pore volume VD5-20 indicated by pores having a pore diameter of 5-20 nm derived by analysis using a nitrogen desorption isotherm by a Dollimore-Heal (DH) method by the pore volume VA20 indicated by pores having a pore diameter of 20 nm or less derived by analysis using a nitrogen desorption isotherm by the DH method is 0.35 or less. (C) In thermal weight differential thermal analysis, a temperature Td 10% that decreases by 10% when the temperature is raised at 10°C / min in an air atmosphere is 620-680°C.

Description

[Technical Field]

[0001] The present disclosure relates to a carbon material for a catalyst support of a polymer electrolyte fuel cell, a catalyst layer for a polymer electrolyte fuel cell, and a fuel cell. [Background technology]

[0002] A polymer electrolyte fuel cell, a type of fuel cell, comprises a pair of catalyst layers disposed on both sides of a solid polymer electrolyte membrane, gas diffusion layers disposed on the outer side of each catalyst layer, and separators disposed on the outer side of each gas diffusion layer. One of the pair of catalyst layers serves as the anode of the polymer electrolyte fuel cell, and the other serves as the cathode of the polymer electrolyte fuel cell. In a typical polymer electrolyte fuel cell, multiple unit cells each having the above components are stacked to obtain the desired output.

[0003] A reducing gas such as hydrogen is introduced into the separator on the anode side. The gas diffusion layer on the anode side diffuses the reducing gas, which is then introduced into the anode. The anode contains a catalyst component, a catalyst support that supports the catalyst component, and an electrolyte material (ionomer) that is proton conductive. The catalyst support is often made of a carbon material. An oxidation reaction of the reducing gas occurs on the catalyst component, producing protons and electrons. For example, when the reducing gas becomes hydrogen gas, the following oxidation reaction occurs: H2→2H + +2e - (E0=0V)

[0004] Protons produced by this oxidation reaction pass through the electrolyte material in the anode and the solid polymer electrolyte membrane and are introduced into the cathode. Electrons pass through the catalyst support, gas diffusion layer, and separator to be introduced into the external circuit. After performing work (generating electricity) in the external circuit, these electrons are introduced into the separator on the cathode side. These electrons then pass through the separator on the cathode side and the gas diffusion layer on the cathode side to be introduced into the cathode.

[0005] The solid polymer electrolyte membrane is made of a proton-conductive electrolyte material and introduces the protons generated in the oxidation reaction to the cathode.

[0006] An oxidizing gas, such as oxygen gas or air, is introduced into the cathode separator. The oxidizing gas diffuses through the cathode gas diffusion layer, which then introduces it into the cathode. The cathode contains a catalyst component, a catalyst support that supports the catalyst component, and a proton-conductive electrolyte material (ionomer). The catalyst support is often made of a carbon material. A reduction reaction of the oxidizing gas occurs on the catalyst component, producing water. For example, when the oxidizing gas becomes oxygen gas or air, the following reduction reaction occurs: O2+4H + +4e - →2H2O (E0=1.23V)

[0007] The water produced by the reduction reaction is discharged outside the fuel cell along with the unreacted oxidizing gas. In this way, solid polymer fuel cells generate electricity by utilizing the energy difference (potential difference) between the oxidation reaction and the reduction reaction. In other words, the electrons produced by the oxidation reaction perform work in an external circuit.

[0008] From the viewpoint of power generation performance of fuel cells, it has been proposed to use porous carbon black as a catalyst carrier. Non-Patent Document 1 reports that catalytic metals supported in pores formed inside porous carbon black are highly active because they are not inhibited (poisoned) by the coexisting ionomer coating. In Patent Document 1, the average particle size is 20 to 100 nm, and the pore volume of the porous carbon black with a pore diameter of 4 to 20 nm is 0.23 to 0.78 cm 3 / g of porous carbon black has been proposed. Patent Document 2 proposes a method of making carbon black porous and increasing its surface area by contacting a carbon black starting material with an oxidizing agent in a fluidized bed. Specifically, Patent Document 2 describes a "method for producing high surface area graphitized carbon, in which the surface area of ​​the starting carbon material is increased by at least 100 m 2 In the preceding article, a "method of producing a high surface area graphitized carbon having a surface area of ​​at least 1.32 cc / g, the method comprising the steps of oxidizing and graphitizing the starting carbon material, the oxidation occurring before the graphitization, the oxidation producing the high surface area carbon, and the high surface area graphitized carbon having an average pore volume of at least 1.32 cc / g."

[0009] Furthermore, from the viewpoint of durability of fuel cells, it has been proposed to calcinate porous carbon black to increase its crystallinity. In Patent Document 3, in order to provide durability, a wire is used for a distance of 300 to 700 m. 2 Highly crystalline carbon black having a BET specific surface area of ​​1.0 μm / g and a crystallite size Lc of 2.0 nm or more has been proposed. In Patent Document 4, Lc(002) is 2.0 nm or more, and the G-band (1590 cm ) in the spectrum of the carbon surface by Raman spectroscopy is -1 ) peak area relative to the D1-band (1350 cm -1 ) peak area ratio D / G is 0.5 to 2.5, and the pores include mesopores, and the mesopore volume is 0.35 to 1.3 cm 3 / g porous carbon has been proposed.

[0010] Furthermore, techniques have also been proposed for activating raw carbon black to obtain porous carbon black. Patent Document 5 proposes a method of making carbon black porous by heat-treating it and then activating it with air. Patent Document 6 proposes a method of activating CO2 after supporting a catalytic metal on carbon black. Patent Document 7 proposes a method of controlling the coating site of an ionomer by air-activating carbon black and changing the pore volume of 5 nm to 40 nm.

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-109856 Patent Document 2: Japanese Patent Publication No. 5650542 Patent Document 3: Patent No. 6478677 Patent Document 4: International Publication No. 17 / 208742 Patent Document 5: Patent No. 6563945 Patent Document 6: Patent No. 5326585 Patent Document 7: Patent No. 6772952

[0012] [Non-Patent Document 1] Kongkanand et al., ACS Energy Lett. 2018, 3, 618-621 Summary of the Invention [Problem to be solved by the invention]

[0013] In solid polymer fuel cells, porous carbon black as a carbon material for a catalyst carrier is required to have not only durability but also low load characteristics (characteristics when generating electricity at low current) as power generation performance. However, in the prior art including the above-mentioned documents, the porous carbon black is still insufficient in terms of achieving both high durability and low load characteristics.

[0014] For example, in Patent Document 5, an activation treatment is performed after heat treatment. Because the heat-treated, highly crystalline carbon wall is activated, the activation effect is low and the improvement in pore volume is insufficient. In addition, because air is used as the activation gas, a combustion reaction occurs on the carbon black surface, resulting in the formation of pores with large diameters, resulting in a structure that makes it easy for ionomer to penetrate into the particle interior. As a result, the improvement in low-load characteristics is insufficient.

[0015] In addition, in Patent Document 6, the supported catalytic metal also acts as an activation catalyst, so that the catalyst support site is selectively activated. As a result, the catalyst particles are present on the carbon surface, which is not sufficient to prevent the catalyst from being poisoned by the ionomer.

[0016] Furthermore, Patent Document 7 describes that the ionomer coating site is controlled by changing the volume of pores of 5 nm to 40 nm. However, the pore volume obtained by analyzing the nitrogen adsorption / desorption isotherm on the adsorption side is not sufficient to express the state of communication between the inside and outside of the particle, and is not optimal as an indicator of whether the ionomer can penetrate.

[0017] In Patent Document 2, a carbon black starting material having a first BET nitrogen surface area is contacted with an oxidant in a fluidized bed under conditions effective to produce a carbon black product having a second BET nitrogen surface area greater than the first BET nitrogen surface area, thereby reacting the oxidant with the carbon black in the fluidized bed to make it porous. However, when carbon black having a particle size distribution is used in a fluidized bed, a distribution occurs in the fluidized state, resulting in a distribution in the degree of activation.

[0018] Therefore, an object of the present disclosure is to provide a carbon material for a catalyst support of a polymer electrolyte fuel cell that combines high durability and low load characteristics, a catalyst layer for a polymer electrolyte fuel cell that uses the same, and a fuel cell. [Means for solving the problem]

[0019] The means for solving the problem include the following aspects. <1> A carbon material for a catalyst support in a polymer electrolyte fuel cell, comprising porous activated carbon black that satisfies the following requirements (A), (B), and (C): (A) BET specific surface area is 350m 2 / g or more 800m 2 / g or less. (B) The pore volume VD of pores with diameters between 5 nm and 20 nm, determined by analyzing the nitrogen desorption isotherm using the Dollimore-Heal (DH) method. 5-20 The pore volume VA of pores with a diameter of 20 nm or less is calculated by analyzing the nitrogen adsorption isotherm using the Dollimore-Heal method. 20 Divided by (VD 5-20 / VA 20 ) is less than or equal to 0.35. (C) In thermogravimetric differential thermal analysis (TG-DTA), the temperature (Td) at which a 10% weight loss occurs when the temperature is increased at 10°C / min in an air atmosphere. 10% is 620 to 680°C. <2> The pore volume VA 20 is 0.36 to 0.90 mL / g <1> 2. The carbon material for a catalyst support of a polymer electrolyte fuel cell according to claim 1. <3> <1> or <2> A catalyst layer for a polymer electrolyte fuel cell, comprising the carbon material for a catalyst support of a polymer electrolyte fuel cell according to claim 1. <4> <3> A fuel cell comprising the catalyst layer for a polymer electrolyte fuel cell according to claim 1. <5> The catalyst layer for a polymer electrolyte fuel cell is a catalyst layer on the cathode side. <4> The fuel cell according to claim 1. [Effects of the Invention]

[0020] According to the present disclosure, there are provided a carbon material for a catalyst support of a polymer electrolyte fuel cell that combines high durability and low load characteristics, a catalyst layer for a polymer electrolyte fuel cell that uses the same, and a fuel cell. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram showing an example of the general configuration of a fuel cell according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] In this disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. Furthermore, when the numerical values ​​written before and after "to" are followed by "greater than" or "less than," the numerical range does not include these numerical values ​​as the lower or upper limit. In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved. In the present disclosure, the "electrolyte material having proton conductivity" used in the catalyst layer of a fuel cell is also referred to as an "ionomer."

[0023] <Carbon materials for catalyst supports in polymer electrolyte fuel cells> The carbon material for a catalyst support of a polymer electrolyte fuel cell according to the present disclosure is made of porous activated carbon black that satisfies the requirements (A), (B), and (C) described below. Here, the porous activated carbon black is carbon black that has been made porous by activation. The porous activated carbon black is also called "porous carbon black."

[0024] The carbon material for a catalyst support according to the present disclosure is a carbon material that combines high durability and low load characteristics. The carbon material according to the present disclosure was discovered based on the following findings.

[0025] In recent years, growing interest in carbon neutrality has led to an increased demand for fuel cells in the field of heavy commercial mobility vehicles (hereinafter referred to as "HDVs"), which produce large amounts of CO2. HDVs require higher durability than passenger cars, so catalyst carriers must be even more durable during power generation, while at the same time, materials must be inexpensive for HDVs, which are primarily used for commercial vehicles.

[0026] It has been found that when porous carbon materials with internal mesopores, such as dendritic carbon materials obtained by the autolysis reaction of silver acetylide, Ketjen Black, or Knobel, are used as carbon materials for catalyst supports, the catalyst supported in the internal mesopores is prevented from being poisoned by the ionomer, resulting in improved activity and low-load characteristics. However, because these porous carbon materials are expensive, it is effective in reducing costs to use porous carbon black, which is made porous by activating carbon black, an inexpensive raw material. However, at present, porous carbon black is still insufficient in terms of achieving both high durability and low load characteristics.

[0027] Therefore, the inventors have investigated the properties of porous carbon black that enable it to have both high durability and low load characteristics, and have obtained the following findings. (1) It is important to "control activation" so that the "specific surface area," "adsorption volume up to 20 nm," and "desorption pore volume of 5 to 20 nm" are simultaneously within their respective suitable ranges. (2) Regarding activation control, activation that increases the uniformity of the activation degree (specifically, for example, activation that reverses the flow direction of the activation gas flowing through the raw carbon black) is effective. (3) Activation with a high degree of uniformity can increase the average pore volume without producing porous carbon black that is overly activated and has enlarged pores connecting the inside and outside. (4) As a result, there is sufficient space inside the porous carbon black for supporting the catalytic metal, and the pores connecting the inside and outside are narrow, preventing the catalytic metal from being poisoned by the ionomer, thereby suppressing a decrease in catalytic activity and a decrease in low-load characteristics. (5) Regarding durability, it is important to “control the heat treatment” so that the “10% weight loss temperature measured by TG-DTA” falls within an appropriate range.

[0028] From the above findings, it has been found that the carbon material for a catalyst support according to the present disclosure is a carbon material that combines high durability and low load characteristics.

[0029] Requirements (A), (B), and (C) are explained below.

[0030] (Requirement (A)) (A) BET specific surface area is 350m 2 / g or more 800m 2 / g or less. The BET specific surface area of ​​porous carbon black is 350m 2 / g or more 800m 2 / g or less is preferable because the catalytic metal to be supported can be supported with good dispersibility at a target loading rate and particle size within a practical range, and the porous carbon black can have a crystallite structure necessary to obtain the durability required for fuel cells. The BET specific surface area of ​​porous carbon black is 350m 2 If the catalyst metal loading rate is less than 1 / g, the catalyst metal particle size increases and the catalyst metal particles aggregate, making it difficult to obtain high cell performance. The BET specific surface area of ​​porous carbon black is 800m 2 / g or more, high power generation performance can be obtained, but the porous carbon black tends to be unable to obtain the crystallite structure necessary to maintain durability, making it difficult to achieve both high durability and low load characteristics. The BET specific surface area of ​​the porous carbon black is preferably 350 m 2 / g or more 600m 2 / g or less.

[0031] The BET specific surface area is a value measured by the method described in the Examples below.

[0032] (Requirement (B)) (B) The pore volume VD of pores with diameters between 5 nm and 20 nm, determined by analyzing the nitrogen desorption isotherm using the Dollimore-Heal (DH) method. 5-20 The pore volume VA of pores with a diameter of 20 nm or less is calculated by analyzing the nitrogen adsorption isotherm using the Dollimore-Heal method. 20 Divided by (VD 5-20 / VA20 ) is less than or equal to 0.35.

[0033] Porous carbon black value (VD 5-20 / VA 20 ) indicates the degree of uniformity of the activation of the porous carbon black. Porous carbon black value (VD 5-20 / VA 20 If the ratio (ratio) exceeds 0.35, the degree of activation will be poor and the number of porous carbon blacks with an excessive number of pores connecting the interior and exterior of the porous carbon black will increase, causing the ionomer to penetrate into the interior of the porous carbon black and deteriorating the low load characteristics.

[0034] In other words, the BET specific surface area is 350m 2 / g or more 800m 2 / g or less and porous car Bomb black value (VD 5-20 / VA 20 When the ionomer ratio is 0.35 or less, the porous carbon black has sufficient space inside to support the catalytic metal, and the pores connecting the inside and outside are narrow. This prevents the catalytic metal from being poisoned by the ionomer, thereby suppressing a decrease in catalytic activity. As a result, a decrease in low-load characteristics is suppressed.

[0035] Porous carbon black value (VD 5-20 / VA 20 ) is preferably 0.30 or less. On the other hand, from the viewpoint of supplying oxygen gas to the internal mesopores and discharging the generated water, the value of porous carbon black (VD 5-20 / VA 20 ) is, for example, 0.10 or more.

[0036] Here, the pore volume of the porous carbon black VD 5-20 represents the amount of pores connecting the inside and outside of the porous carbon black, and indicates the ease with which the ionomer penetrates into the inside of the porous carbon black. Pore ​​volume VD of porous carbon black 5-20is preferably 0.4 mL / g or less, more preferably 0.3 mL / g or less. Pore ​​volume VD of porous carbon black 5-20 When the ionomer concentration is 0.4 mL / g or less, the uniformity of the activation degree is improved, and the number of pores connecting the interior and exterior of the porous carbon black is prevented from becoming excessively large, which makes it difficult for the ionomer to penetrate into the interior of the porous carbon black, thereby improving the low-load characteristics. However, from the viewpoint of supplying oxygen gas to the mesopores inside the porous carbon black and discharging the generated water, the pore volume VD 5-20 The lower limit is, for example, 0.05 mL / g or more.

[0037] On the other hand, the pore volume VA of porous carbon black 20 represents the pore volume inside the porous carbon black. Pore ​​volume VA of porous carbon black 20 The concentration is preferably 0.36 to 0.90 mL / g, and more preferably 0.39 to 0.61 mL / g. Pore ​​volume VA of porous carbon black 20 When the ionomer content is 0.36 mL / g or more, the internal volume of the porous carbon black is sufficiently secured, and the amount of catalytic metal supported inside the porous carbon black increases, thereby reducing the catalytic metal poisoning by the ionomer and improving low-load characteristics. Pore ​​volume VA of porous carbon black 20 When the pore volume of the porous carbon black is 0.9 mL / g or less, the pore volume inside the porous carbon black is large, and uniformity in the degree of activation is ensured, while the porous carbon black has sufficient strength to suppress collapse, thereby improving durability.

[0038] The pore volume VD 5-20 , and pore volume VA 20 is a value measured by the method described in the Examples below.

[0039] (Requirement (C)) (C) In thermogravimetric differential thermal analysis (TG-DTA), the temperature (Td) at which a 10% weight loss occurs when the temperature is increased at 10°C / min in an air atmosphere. 10% is 620 to 680°C. 10% weight loss temperature Td of porous carbon black 10% If the temperature is less than 620°C, the porous carbon black will be highly susceptible to oxidation and will not be able to ensure sufficient durability. 10% weight loss temperature Td of porous carbon black 10% If the temperature exceeds 680°C, the surface area of ​​the porous carbon black decreases, and the low load characteristics deteriorate. 10% weight loss temperature Td of porous carbon black 10% The temperature is preferably 640 to 680°C.

[0040] The 10% weight loss temperature Td 10% is measured by the method described in the Examples below. This is the value that is set.

[0041] <Method for producing carbon material for catalyst support of polymer electrolyte fuel cells> An example of a method for producing a carbon material for a catalyst support of a polymer electrolyte fuel cell according to the present disclosure (hereinafter also referred to as a "carbon material production method") will be described below.

[0042] The method for producing a carbon material according to the present disclosure is an activation method in which raw carbon black is treated in the order of a "first activation step," a "heat treatment step," and a "second activation step," and in the "first activation step," the flow direction of the activation gas flowing through the raw carbon black is reversed. The method for producing a carbon material according to the present disclosure makes it possible to obtain a carbon material (that is, porous activated carbon black) that satisfies requirements (A) to (C).

[0043] (First activation step) In the first activation step, the flow direction of the activation gas flowing through the raw carbon black is reversed for activation. The reversal of the flow direction of the activation gas may be performed once or may be repeated two or more times. By reversing the flow direction of the activation gas, it is possible to suppress the difference in activation degree that occurs between the raw carbon black on the upstream side of the activation gas flow channel and the raw carbon black on the downstream side of the activation gas flow channel, thereby increasing the uniformity of the activation degree of the porous carbon black.

[0044] Examples of raw carbon black include furnace black, which is produced by continuously pyrolyzing a gaseous or liquid raw material in a reactor; channel black, which is produced by burning a raw material gas and applying the flame to the bottom surface of a channel steel to rapidly cool and precipitate the material; thermal black, which is produced by periodically repeating combustion and pyrolysis of a gas as the raw material; and acetylene black, which is produced from acetylene gas as the raw material. Furnace black is preferred as the raw carbon black from the viewpoints of ease of generating internal pores upon activation and a primary particle size suitable for use as a catalyst support for solid polymer fuel cells. These carbon blacks can be used alone or in combination of two or more kinds, but from the viewpoint of uniformly progressing activation, it is preferable to use them alone.

[0045] (heat treatment process) In the heat treatment step performed after the first activation step, heat treatment is performed in an inert atmosphere to grow the crystallites that make up the raw carbon black that has undergone the first activation step, thereby imparting the durability required for fuel cells. By performing the heat treatment step, the 10% weight loss temperature Td of the porous carbon black is reached. 10% This keeps the temperature high, improving oxidation resistance (i.e. durability).

[0046] In the heat treatment step, the raw carbon black that has been subjected to the first activation step is heat treated in a vacuum or in an inert gas (nitrogen, argon, etc.) atmosphere at a temperature of 1500°C or higher and 1900°C or lower (preferably 1600 to 1800°C). Heat treatment at 1500°C or higher develops highly aromatic carbon crystals that form the skeleton of the porous carbon black, and the pore walls become sufficiently thick, resulting in porous carbon black that satisfies requirement (C). Heat treatment at 1900°C or below prevents the reduction in mesopore volume due to excessive crystallization of carbon.

[0047] (Second activation step) In the second activation step, the pores of the heat-treated activated carbon black intermediate that were closed in the heat treatment step are reopened, thereby increasing the specific surface area and pore volume that were reduced in the heat treatment step. Without the second activation step, it is difficult to obtain a sufficient specific surface area and pore volume. In the second activation step, too, it is preferable to reverse the flow direction of the activation gas flowing through the raw carbon black to activate it.

[0048] Then, by undergoing the first activation step and the second activation step, porous carbon black is obtained that has sufficient space inside the porous carbon black for supporting the catalytic metal and has narrow pores connecting the inside and outside, thereby satisfying requirements (A) and (B).

[0049] (Activation Modes of the First Activation Step and the Second Activation Step) The type of activation gas used in the first activation step and the second activation step is not particularly limited as long as it contains a gas capable of oxidizing and consuming the carbon constituting the raw carbon black through a reaction. Examples of gases capable of oxidizing and consuming the carbon constituting the raw carbon black through a reaction include air, oxygen, ozone, water vapor, carbon dioxide, nitrogen dioxide, nitric oxide, and nitrous oxide. The activation gas may be a mixture of these gases. Alternatively, the activation gas may be a gas diluted with an inert gas such as nitrogen, argon, or helium. Furthermore, exhaust gases or industrial gases containing these gases may also be used. Preferably, the activation gas is water vapor or carbon dioxide, or a gas containing these. The type of gas used in the first activation step and the second activation step may be different.

[0050] As the activation device for the first activation step and the second activation step, various types of devices such as a rotary kiln, a fluidized bed furnace, a fixed bed furnace, a moving bed furnace, etc. can be used, and either a continuous furnace in which raw materials are continuously charged and the product is discharged, or a batch furnace in which they are conducted intermittently, can be used. As the activation device, a rotary kiln and a fixed bed furnace are preferred because they allow easy switching of the gas introduction direction. Furthermore, from the viewpoint of uniformity of the activation degree, a batch furnace is preferred because a continuous furnace in which raw materials are continuously charged causes a distribution in the activation degree.

[0051] In the activation apparatus for activating the raw material carbon black in the first activation step and the second activation step (particularly the first activation step), it is preferable to change the direction of introduction of the activation gas. To change the gas introduction direction, the inlet and outlet of the gas flow path may be interchanged, or, when a tubular furnace or the like is used as the activation apparatus, the direction of the furnace tube may be reversed and connected. The proportion of gas supply flowing from the initial gas introduction direction at the end of activation can be expressed as GasR ([supply amount from initial gas introduction direction / (supply amount from initial gas introduction direction + supply amount from gas introduction direction reversed from the initial direction)] × 100. The GasR value is preferably 30 to 70%. If the GasR value is 70% or more, the activation level of the raw material carbon black present on the initial gas introduction side will proceed excessively, impairing activation uniformity. On the other hand, if the GasR value is 30% or less, the activation level of the raw material carbon black present on the initial gas discharge side will proceed excessively, impairing activation uniformity.

[0052] <Catalyst layer for polymer electrolyte fuel cell and polymer electrolyte fuel cell> The polymer electrolyte fuel cell will now be described together with the catalyst layer for a polymer electrolyte fuel cell of the present disclosure. The carbon material of the present disclosure can be applied to, for example, catalyst layers 150 and 160 provided in a polymer electrolyte fuel cell 100 shown in Fig. 1. Fig. 1 is a schematic diagram showing an example of the general configuration of a fuel cell of the present disclosure. The polymer electrolyte fuel cell 100 shown in FIG. 1 includes separators 110 and 120, gas diffusion layers 130 and 140, catalyst layers 150 and 160, and an electrolyte membrane 170.

[0053] Separator 110 is an anode-side separator that introduces a reducing gas such as hydrogen into gas diffusion layer 130. Separator 120 is a cathode-side separator that introduces an oxidizing gas such as oxygen gas or air into the gas diffusion condensation layer. The types of separators 110 and 120 are not particularly limited, and may be any separator used in conventional fuel cells (e.g., solid polymer fuel cells).

[0054] The gas diffusion layer 130 is an anode-side gas diffusion layer that diffuses the reducing gas supplied from the separator 110 and then supplies the gas to the catalyst layer 150. The gas diffusion layer 140 is a cathode-side gas diffusion layer that diffuses the oxidizing gas supplied from the separator 120 and then supplies the gas to the catalyst layer 160. The type of gas diffusion layers 130 and 140 is not particularly limited, and they may be any gas diffusion layer used in conventional fuel cells (e.g., polymer electrolyte fuel cells). Examples of the gas diffusion layers 130 and 140 include porous carbon materials (carbon cloth, carbon paper, etc.) and porous metal materials (metal mesh, metal wool, etc.). A preferred example of the gas diffusion layers 130 and 140 is a gas diffusion layer with a two-layer structure. Specifically, the gas diffusion layers 130 and 140 have a two-layer structure in which the layer on the separator 110 or 120 side is a gas diffusion fiber layer mainly composed of a fibrous carbon material, and the layer on the catalyst layer 150 or 160 side is a micropore layer mainly composed of carbon black.

[0055] The catalyst layer 150 is a so-called anode. An oxidation reaction of the reducing gas occurs in the catalyst layer 150, producing protons and electrons. For example, when the reducing gas becomes hydrogen gas, the following oxidation reaction occurs. H2→2H + +2e - (E0=0V)

[0056] Protons produced by the oxidation reaction pass through the catalyst layer 150 and the electrolyte membrane 170 to reach the catalyst layer 160. Electrons produced by the oxidation reaction pass through the catalyst layer 150, the gas diffusion layer 130, and the separator 110 to reach the external circuit. After performing work (generating electricity) in the external circuit, the electrons are introduced into the separator 120. The electrons then pass through the separator 120 and the gas diffusion layer 140 to reach the catalyst layer 160.

[0057] There are no particular limitations on the configuration of the catalyst layer 150 that serves as the anode. The configuration of the catalyst layer 150 may be the same as that of a conventional anode, the same as that of the catalyst layer 160, or a configuration that is more hydrophilic than that of the catalyst layer 160.

[0058] The catalyst layer 160 is a so-called cathode. Within the catalyst layer 160, a reduction reaction of the oxidizing gas occurs, producing water. For example, when the oxidizing gas becomes oxygen gas or air, the following reduction reaction occurs: The water produced by the oxidation reaction is discharged to the outside of the polymer electrolyte fuel cell 100 together with the unreacted oxidizing gas. O2+4H + +4e - →2H2O (E0=1.23V)

[0059] In this way, the energy difference (potential difference) between the oxidation reaction and the reduction reaction is utilized to generate electricity in the polymer electrolyte fuel cell 100. In other words, the electrons generated in the oxidation reaction perform work in an external circuit.

[0060] The catalyst layer 160 contains the carbon material for a catalyst support of the present disclosure. That is, the catalyst layer 160 contains the carbon material for a catalyst support of the present disclosure, an electrolyte material (ionomer), and a catalyst component (platinum, etc.). This can improve the durability and low-load characteristics within the catalyst layer 160. This can also improve the durability and low-load characteristics of the solid polymer electrolyte fuel cell 100.

[0061] The catalyst loading rate in the catalyst layer 160 is not particularly limited, and is preferably 30% by mass or more and less than 80% by mass. A catalyst loading rate within this range further enhances durability and low load characteristics. Here, the catalyst loading rate is expressed as the mass % of the catalyst component relative to the total mass of the catalyst-loaded particles (particles in which the catalyst component is loaded on a carbon material for a catalyst carrier). If the catalyst loading rate is less than 30% by mass, it may be necessary to thicken the catalyst layer 160 to make the polymer electrolyte fuel cell 100 practical. On the other hand, if the catalyst loading rate is 80% by mass or more, catalyst aggregation is likely to occur. Furthermore, if the catalyst layer 160 becomes too thin, flooding may occur.

[0062] The mass ratio I / C of the mass I of the electrolyte material in the catalyst layer 160 to the mass C of the catalyst support carbon material is not particularly limited, but is preferably greater than 0.5 and less than 5.0. In this case, both the pore network and the electrolyte material network are compatible, resulting in improved durability and low-load characteristics. On the other hand, if the mass ratio I / C is 0.5 or less, the electrolyte material network tends to be weak and the proton conduction resistance tends to increase. If the mass ratio I / C is 5.0 or more, the pore network may be disrupted by the electrolyte material. In either case, durability and low-load characteristics may be reduced.

[0063] Furthermore, the thickness of the catalyst layer 160 is not particularly limited, but is preferably more than 5 μm and less than 20 μm. In this case, the oxidizing gas is more likely to diffuse within the catalyst layer 160, and flooding is less likely to occur. If the thickness of the catalyst layer 160 is 5 μm or less, flooding is more likely to occur. If the thickness of the catalyst layer 160 is 20 μm or more, the oxidizing gas is less likely to diffuse within the catalyst layer 160, and the catalytic components near the electrolyte membrane 170 become less active. In other words, the catalyst utilization rate may decrease.

[0064] The electrolyte membrane 170 is made of an electrolyte material having proton conductivity. The electrolyte membrane 170 introduces protons generated in the oxidation reaction to the catalyst layer 160 (cathode). The type of electrolyte material is not particularly limited, and any electrolyte material used in conventional fuel cells, such as solid polymer fuel cells, may be used. An example of a suitable electrolyte material is an electrolyte resin. Examples of electrolyte resins include polymers into which phosphate groups, sulfonic acid groups, etc. are introduced. Specific examples include perfluorosulfonic acid polymers and polymers into which benzenesulfonic acid, etc., are introduced. Of course, other types of electrolyte materials may also be used. Examples of such electrolyte materials include inorganic and inorganic-organic hybrid electrolyte materials. The solid polymer fuel cell 100 may be a fuel cell that operates within a temperature range of room temperature (25°C) to 150°C.

[0065] <Method of manufacturing a polymer electrolyte fuel cell> The method for manufacturing the polymer electrolyte fuel cell 100 is not particularly limited, and may be the same as a conventional manufacturing method. However, the catalyst carrier is made of the carbon material for a catalyst carrier of the present disclosure. Of the catalyst layers 150 and 160, it is preferable to use the carbon material for a catalyst carrier of the present disclosure for the catalyst carrier of at least the catalyst layer 160 that serves as the cathode. Of course, the carbon material for a catalyst carrier of the present disclosure may also be used for the catalyst carrier of both the catalyst layer 150 that serves as the anode and the catalyst layer 160 that serves as the cathode. [Example]

[0066] Experimental examples of the carbon material for a catalyst support according to the present disclosure will be described below. First, the method for measuring each parameter will be described.

[0067] <Measuring methods for each parameter> (Nitrogen adsorption / desorption isotherm (VA 20 , V.D. 5-20 , BET specific surface area) Approximately 30 mg of a sample of the carbon material for catalyst support was weighed out and vacuum dried at 200°C for 2 hours. After that, the nitrogen adsorption-desorption isotherm was measured using an automatic specific surface area analyzer (AUTOSORB iQ, manufactured by Anton Paar Japan) with nitrogen gas as the adsorbate. Pore ​​volume VA of pores with diameters of 20 nm or less 20 , and the pore volume VD of pores with diameters of 5 to 20 nm 5-20 The nitrogen adsorption and desorption isotherms were analyzed by the DH method using the software attached to the device. The calculation was made as follows. The BET specific surface area was calculated by BET analysis of the nitrogen adsorption isotherm in the range of relative pressure P / P0 of 0.30 or less.

[0068] (10% weight loss temperature Td in thermogravimetric differential thermal analysis (TG-DTA) 10% (measurement of Approximately 6 mg of the carbon material for catalyst support was used as a sample. The sample was then placed in a thermogravimetric and differential calorimeter (Hitachi High-Technologies Corporation, EXSTAR TG / DTA7200) and the weight loss was measured up to 900°C at a heating rate of 10°C / min and a dry air flow of 200 mL / min. The weight at the start of the weight loss curve was taken as 100%, and the weight at the end of the measurement was taken as 0%. The temperature at which the weight lost 10% was determined as the 10% weight loss temperature, Td. 10% It was decided.

[0069] <Example: Preparation of carbon material for catalyst support> Example 1 (1) First activation step A 1-inch diameter tubular reactor was filled with 7 g of Niteron #10 carbon black (manufactured by Nippon Steel Carbon) as the raw material, and a mass flow controller set upstream of the tubular reactor was used to flow CO gas at 400 Nml / min. In this state, the tubular reactor was heated to 840 °C at a rate of 20 °C / min. and held at 840 °C for 36 hours. Then, valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of the gas introduced into the tubular reactor, and the reactor was held at 840 °C for another 36 hours, performing the first activation step. After holding, the flow gas was switched to N2, the temperature was lowered, and the first activation sample was collected.

[0070] (2) Heat treatment process The entire amount of the recovered first activation sample was placed in a heating crucible, and the temperature was increased at 15°C / min in a heating furnace under Ar flow, and a heat treatment step was carried out at 1600°C for 1 hour, and a heat-treated sample was recovered.

[0071] (3) Second activation step The entire heat-treated sample was again loaded into a 1-inch diameter tubular reactor, and a mass flow controller installed upstream of the tubular reactor was used to circulate CO gas at 400 Nml / min. In this state, the tubular reactor was heated to 850°C at 20°C / min and held at 850°C for 15 minutes. Subsequently, the valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of gas flow into the tubular reactor, and the temperature was held at 850°C for an additional 15 minutes, performing a second activation. After holding, the flow gas was switched to N2, and the temperature was lowered. The second activated sample obtained by these operations was collected as the carbon material for a catalyst support of Example 1 (that is, the porous activated carbon black).

[0072] Example 2 A carbon material for a catalyst support (that is, porous activated carbon black) was obtained in the same manner as in Example 1, except that the holding temperature in the heat treatment step was 1800°C.

[0073] Example 3 In the first activation step, the tubular reactor was heated and then maintained at 840°C for 24 hours, and then the valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of the gas introduced into the tubular reactor, and the reactor was further maintained at 840°C for 48 hours. Except for this, a carbon material for a catalyst support (i.e., porous activated carbon black) was obtained in the same manner as in Example 1.

[0074] Example 4 In the first activation step, the temperature of the tubular reactor was increased to 820°C at a rate of 20°C / min., and the temperature was maintained at 820°C for 36 hours. Then, the valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of the gas introduced into the tubular reactor, and the temperature was maintained at 820°C for another 36 hours. Except for this, a carbon material for a catalyst support (i.e., porous activated carbon black) was obtained in the same manner as in Example 1.

[0075] Example 5 In the first activation step, the temperature of the tubular reactor was increased to 820°C at a rate of 20°C / min. and maintained at 820°C for 36 hours. Then, the valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of the gas introduced into the tubular reactor, and the temperature was maintained at 820°C for another 36 hours. A carbon material for a catalyst support (i.e., porous activated carbon black) was obtained in the same manner as in Example 1, except that the holding time in the second activation step was set to 2 hours (1 hour each before and after reversing the gas direction, totaling 2 hours).

[0076] Example 6 In the first activation step, Nittelon #3350 manufactured by Nippon Steel Carbon was used as the raw material carbon black, and the temperature of the tubular reactor was raised to 1000°C at a rate of 20°C / min. and maintained at 1000°C for 3 hours. After that, the valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of the gas being introduced into the tubular reactor, and the reactor was maintained at 1000°C for another 3 hours. The holding temperature of the heat treatment process was changed to 1700°C. A carbon material for a catalyst support (i.e., porous activated carbon black) was obtained in the same manner as in Example 1, except that the holding temperature in the second activation step was 950°C and the holding time was 4 hours (2 hours each before and after reversing the gas direction, totaling 4 hours).

[0077] Example 7 In the first activation step, Nittelon #3350 manufactured by Nippon Steel Carbon was used as the raw material carbon black, and the temperature of the tubular reactor was raised to 1000°C at a rate of 20°C / min. and maintained at 1000°C for 3 hours. After that, the valves installed upstream and downstream of the tubular reactor were operated to reverse the direction of the gas being introduced into the tubular reactor, and the reactor was maintained at 1000°C for another 3 hours. The holding temperature of the heat treatment process was changed to 1700°C. A carbon material for a catalyst carrier (i.e., porous activated carbon black) was obtained in the same manner as in Example 1, except that the holding temperature in the second activation step was 950°C and the holding time was 2 hours (1 hour each before and after reversing the gas direction, totaling 2 hours).

[0078] Example 8 In the first activation step, 230 g of Nitelon #10 (manufactured by Nippon Steel Carbon) raw carbon black was packed to a uniform thickness into a cylindrical retort container with an inner diameter of 120 mm and a length of 500 mm, equipped with four lifters. The retort container was then placed inside a rotary kiln, CO gas was introduced at a flow rate of 3000 Nml / min, and the rotary kiln was rotated at a speed of one revolution per second. In this state, the rotary kiln was heated to 850 °C at a rate of 20 °C / min and held at 850 °C for 35 hours. After this hold, the flow gas was switched to N2, the temperature was lowered, the retort container was removed from the rotary kiln, and the container was inverted and reinstalled in the rotary kiln. CO gas was then introduced at a flow rate of 3000 Nml / min, and the rotary kiln was rotated at a speed of one revolution per second. In this state, the rotary kiln was heated to 850°C at a rate of 20°C / min and then maintained at 850°C for a further 35 hours. After this temperature was reached, the flow gas was switched to N2, the temperature was lowered, and the first activation sample was recovered. The holding temperature in the second activation step was 950° C., and the holding time was 0.5 hours (15 minutes each before and after reversing the gas direction, totaling 0.5 hours). The same procedure as in Example 1 was carried out except for these operations.

[0079] (Comparative Example 1) A carbon material for a catalyst support was obtained in the same manner as in Example 1, except that in the first activation step, the direction of the gas introduced into the tubular reactor was not reversed.

[0080] (Comparative Example 2) A carbon material for a catalyst support was obtained in the same manner as in Example 8, except that in the first activation step, the retort container was removed from the rotary kiln and was not turned over.

[0081] (Comparative Example 3) A carbon material for a catalyst support was obtained in the same manner as in Example 8, except that in the first activation step, the holding time before inverting the retort container was 56 hours and the holding time after inverting the retort container was 14 hours.

[0082] Comparative Example 4 A carbon material for a catalyst support was obtained in the same manner as in Example 8, except that in the first activation step, the holding time before inverting the retort container was 14 hours and the holding time after inverting the retort container was 56 hours.

[0083] (Comparative Example 5) A carbon material for a catalyst support was obtained in the same manner as in Example 1, except that the second activation step was not carried out.

[0084] (Comparative Example 6) A carbon material for a catalyst support was obtained in the same manner as in Example 1, except that the holding temperature in the heat treatment step was set to 1400°C.

[0085] (Comparative Example 7) A carbon material for a catalyst support was obtained in the same manner as in Example 1, except that the holding temperature in the heat treatment step was set to 1200°C.

[0086] (Comparative Example 8) A carbon material for a catalyst support was obtained in the same manner as in Example 1, except that the holding temperature in the heat treatment step was set to 2000°C.

[0087] (Comparative Example 9) Ketjen Black EC300J manufactured by Lion Specialty Chemicals Co., Ltd., which was not subjected to any additional treatment, was used as the carbon material for a catalyst support in Comparative Example 9.

[0088] (Comparative Example 10) Ketjen Black EC600JD manufactured by Lion Specialty Chemicals Co., Ltd., which was not subjected to any additional treatment, was used as the carbon material for a catalyst support in Comparative Example 10.

[0089] (Comparative Example 11) 2 g of Ketjen Black EC300J (Lion Specialty Chemicals Co., Ltd.) was used as the raw carbon black and was subjected to a heat treatment process in a heat treatment furnace under an Ar flow at 1600°C for 1 hour to obtain a carbon material for a catalyst support of Comparative Example 11.

[0090] (Comparative Example 12) As the raw material carbon black, 2 g of Ketjen Black EC600JD manufactured by Lion Specialty Chemicals Co., Ltd. was subjected to a heat treatment process in a heat treatment furnace under an Ar flow at 1600°C for 1 hour to obtain a carbon material for a catalyst support of Comparative Example 12.

[0091] <Catalyst preparation, catalyst layer preparation, MEA fabrication, fuel cell assembly, and evaluation of cell performance (power generation performance, durability)> Next, using each of the porous carbon blacks prepared as described above, a catalyst for a polymer electrolyte fuel cell carrying a catalytic metal was prepared as follows: a catalyst layer ink solution was prepared using the obtained catalyst; a catalyst layer was then formed using this catalyst layer ink solution; a membrane electrode assembly (MEA) was fabricated using the formed catalyst layer; the fabricated MEA was incorporated into a fuel cell; and a power generation test was performed using a fuel cell measuring device. The preparation of each component and cell evaluation through the power generation test are described in detail below.

[0092] (1) Preparation of catalysts (platinum-supported carbon materials) for polymer electrolyte fuel cells Each carbon material for catalyst support was dispersed in distilled water. Formaldehyde was added to the dispersion, which was then placed in a water bath set at 40°C. Once the temperature of the dispersion reached the same temperature as the bath (40°C), an aqueous solution of dinitrodiamine platinum complex nitric acid was slowly poured into the stirred dispersion. Stirring was continued for approximately 2 hours, followed by filtration and washing of the resulting solid. The solid was vacuum dried at 90°C, pulverized in a mortar, and then heat-treated at 200°C for 1 hour in an argon atmosphere containing 5% hydrogen by volume to produce a platinum-supported carbon material. The platinum loading of the platinum-supported carbon material was adjusted to 35% by mass relative to the total mass of the catalyst support carbon material and platinum particles, and was confirmed by inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0093] (2) Preparation of the catalyst layer Using the platinum-supported carbon material (Pt catalyst) prepared as described above and a 5 mass % Nafion solution (DE2020CS, registered trademark: Nafion, manufactured by DuPont) as the electrolyte resin, the Pt catalyst and Nafion were mixed under an Ar atmosphere in a ratio of 1.0 times the mass of the Nafion solid content to the mass of the porous carbon black (the mass of only the porous carbon black in the Pt catalyst excluding the Pt content), and after light stirring, the Pt catalyst was crushed using ultrasound. Ethanol was further added to adjust the total solid content concentration of the Pt catalyst and electrolyte resin to 0.5 mass %, thereby preparing a catalyst layer ink liquid in which the Pt catalyst and electrolyte resin were mixed.

[0094] Using the catalyst layer ink liquid prepared in this manner, the spray conditions were adjusted so that the mass of platinum per unit area of ​​the catalyst layer (hereinafter referred to as "platinum coverage") was 0.2 mg / cm, and the catalyst layer ink was sprayed onto a Teflon (registered trademark) sheet, followed by a drying treatment in argon at 120°C for 60 minutes to produce a catalyst layer.

[0095] (3) Fabrication of MEA Using the catalyst layer prepared as above, an MEA (membrane electrode assembly) was prepared by the following method. A square electrolyte membrane with sides of 6 cm was cut out from a Nafion membrane (NR211 manufactured by DuPont). The anode and cathode catalyst layers coated on Teflon (registered trademark) sheets were each cut into a square with sides of 2.5 cm using a cutter knife. The electrolyte membrane was sandwiched between the catalyst layers of the anode and cathode cut out in this way so that each catalyst layer was in contact with the center of the electrolyte membrane and there was no misalignment between them, and pressed at 120°C and 100 kg / cm² for 10 minutes, then cooled to room temperature, and the Teflon (registered trademark) sheets were carefully peeled off from both the anode and cathode. A catalyst layer-electrolyte membrane assembly was prepared in which the catalyst layers of the cathode and the cathode were fixed to the electrolyte membrane.

[0096] Next, a pair of square carbon paper sheets, each 2.5 cm on a side, was cut out from carbon paper (39BC manufactured by SGL Carbon Co., Ltd.) to form a gas diffusion layer. The catalyst layer-electrolyte membrane assembly was sandwiched between these carbon papers so that the anode and cathode catalyst layers were aligned and not misaligned. The assembly was then heated at 120°C and 50 kg / cm 2 The mixture was pressed at 100°C for 10 minutes to prepare an MEA. The basis weight of each component of the catalytic metal component, carbon material, and electrolyte material in each of the produced MEAs was calculated from the mass ratio of the composition of the catalyst layer by determining the mass of the catalyst layer fixed to the Nafion membrane (electrolyte membrane) from the difference between the mass of the Teflon (registered trademark) sheet with the catalyst layer before pressing and the mass of the Teflon (registered trademark) sheet peeled off after pressing.

[0097] (4) Fuel cell assembly and initial power generation performance evaluation The MEAs produced using the porous carbon materials according to the examples and comparative examples were incorporated into cells, which were then set in a fuel cell measuring device, and the initial power generation performance of the fuel cells was evaluated according to the following procedure. Air was supplied to the cathode side, and pure hydrogen was supplied to the anode side. The pressure was adjusted using a back pressure valve installed downstream of the cell to achieve a back pressure gauge pressure of 0.1 MPaG, with utilization rates of 40% and 70%, respectively. The cell temperature was set to 80°C, and the air and pure hydrogen supplied to the fuel cell were humidified by passing them through distilled water kept at 80°C in a humidifier (i.e., bubbling). This set the relative humidity of the anode and cathode to approximately 100%. Under these settings, the reaction gas was supplied to the cell, and the operation of gradually increasing the current density until the cell terminal voltage reached 0.3 V was repeated 10 times. Then, the current density was reduced to 0.2 A / cm 2 The voltage between the cell terminals was recorded when the battery was held at this temperature for 10 minutes, and the low load performance was evaluated using the following criteria: pass rank A or B, and fail rank C. The results are shown in Table 1. [Passing rank] A: Current density 0.2A / cm 2 The cell terminal voltage is 0.83V or more. B: Current density 0.2A / cm 2 The voltage between the cell terminals is 0.81V or more. [Failure rank] C: Does not meet the passing grade B.

[0098] (5) Durability evaluation After the initial power generation performance evaluation, a durability test was conducted under the following conditions. First, the cell temperature was 80°C, the relative humidity was 100%, the cell back pressure was 0.0 MPaG, and the cathode gas was switched to argon gas. Next, the cell voltage was set to 0.6 V and held for 4 seconds, followed by 1.2 V and held for 4 seconds. This square-wave voltage fluctuation cycle was repeated 1,000 times. The anode and cathode gas utilization rates were then set to 40% and 70%, respectively, the cell back pressure was 0.1 MPaG, the cell temperature was 80°C, the relative humidity was 100%, and the current density was recorded at a cell voltage of 0.3 V. Durability was evaluated using the following criteria: pass rank A, B, and fail rank C. The results are shown in Table 1. [Passing rank] A: The current density after 1000 cycles is 80% or more of the current density during the initial power generation performance evaluation. B: The current density after 1000 cycles is 70% or more of the current density during the initial power generation performance evaluation. [Failure rank] C: Does not meet the passing grade B.

[0099] [Table 1-1]

[0100] [Table 1-2]

[0101] From the above results, it is clear that the carbon material for a catalyst carrier of the example (that is, the porous activated carbon black) can achieve both high durability and low load characteristics.

[0102] The symbols are explained as follows: 100 Solid polymer fuel cell 110, 120 separator 130, 140 Gas diffusion layer 150, 160 catalyst layer 170 Electrolyte membrane

[0103] The disclosure of Japanese Patent Application No. 2023-108951 is incorporated herein by reference in its entirety. All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A carbon material for a catalyst support in a polymer electrolyte fuel cell, comprising porous activated carbon black that satisfies the following requirements (A), (B), and (C): (A) BET specific surface area is 350 m ２ / g or more 800m ２ / g or less. (B) The pore volume VD of pores with a pore diameter of 5 nm or more and 20 nm or less, obtained by analyzing the nitrogen desorption isotherm using the DH (Dollimore-Heal) method. ５－２０ The pore volume VA of pores with a pore diameter of 20 nm or less, which is obtained by analyzing the nitrogen adsorption isotherm using the DH (Dollimore-Heal) method, ２０ The value divided by (VD ５－２０ / VA ２０ ) is 0.35 or less, and the pore volume VA 20 is 0.36 to 0.90 mL / g. (C) In thermogravimetric differential thermal analysis (TG-DTA), the temperature Td at which a 10% weight loss occurs when the temperature is increased at 10°C / min in an air atmosphere １０％ is 620 to 680°C.

2. A catalyst layer for a polymer electrolyte fuel cell, comprising the carbon material for a catalyst support of a polymer electrolyte fuel cell according to claim 1.

3. A fuel cell comprising the catalyst layer for a polymer electrolyte fuel cell according to claim 2.

4. 4. The fuel cell according to claim 3, wherein the catalyst layer for a polymer electrolyte fuel cell is a catalyst layer on the cathode side.

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