Porous carbon material and method for producing same

Abstract

This porous carbon material: has, in a pore size diameter distribution measured by a mercury intrusion method, a peak located in a pore size diameter range of not less than 3 nm but less than 10 nm; exhibits, in a nitrogen adsorption isotherm, a difference of 110 cm3 / g or more between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98; and exhibits a nitrogen adsorption amount of 150 cm3 / g or less at a relative pressure of 0.07.

Description

Porous carbon material and method for producing the same

[0001] The present disclosure relates to a porous carbon material and a method for producing the same.

[0002] Carbon materials, particularly porous carbon materials having fine pores, are useful for applications such as catalyst supports and electrode materials, and various production methods have been investigated. For example, Patent Document 1 discloses a method of obtaining activated carbon by heating a mixture of a block copolymer having a hydrophilic block and a hydrophobic block, a phenol, formaldehyde, and a solvent to obtain porous carbon, and then activating the porous carbon.

[0003] JP 2014-034475 A

[0004] In recent years, porous carbon materials with better oxidation resistance are desired due to the expansion of applications. Furthermore, in applications in which a reaction substrate is reacted on an active metal (i.e., on a reaction site) supported on a porous carbon material, the presence of sufficient wide voids, such as interparticle voids, is desirable.

[0005] An object of the present disclosure is to provide a porous carbon material that has a sufficient amount of wide voids, such as interparticle voids, and has good oxidation resistance, and is suitable as a catalyst support. Another object of the present disclosure is to provide a method for easily producing the porous carbon material.

[0006] The present disclosure relates to, for example, the following [1] to [4]: ​​[1] A pore size distribution measured by mercury intrusion porosimetry has a peak located in a pore size range of 3 nm or more and less than 10 nm, and a nitrogen adsorption isotherm has a difference of 110 cm between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98. ３ / g or more, and the nitrogen adsorption amount at a relative pressure of 0.07 is 150 cm ３ [2] A porous carbon material in which the difference between the amount of nitrogen adsorption in a nitrogen adsorption isotherm and the amount of nitrogen adsorption in a nitrogen desorption isotherm is 150 cm / g or less at any relative pressure between 0.90 and 0.99. ３[3] The porous carbon material according to [1], wherein the difference between the amount of nitrogen adsorption in the nitrogen adsorption isotherm and the amount of nitrogen adsorption in the nitrogen desorption isotherm is 140 cm / g or less at any relative pressure from 0.90 to 0.99. ３ [4] The porous carbon material according to [2], wherein the difference between the amount of nitrogen adsorption in the nitrogen adsorption isotherm and the amount of nitrogen adsorption in the nitrogen desorption isotherm is 150 cm / g or less at any relative pressure from 0 to 0.99. ３ [5] The porous carbon material according to any one of [1] to [3], wherein the porous carbon material has a nitrogen adsorption of 150 cm3 at a relative pressure of 0.07 in a nitrogen adsorption isotherm of the porous carbon material, the nitrogen adsorption of 150 cm3 at a relative pressure of 0.07 in a nitrogen adsorption isotherm of the porous carbon material, and the porous carbon material has a .... ３ / g or less, and the pulverization step is a step of pulverizing the resin molded body so that the difference between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98 in a nitrogen adsorption isotherm of the porous carbon material is 110 cm ３ [6] The method for producing a porous carbon material according to [5], wherein the mesopore-forming template contains amphiphilic molecules.

[0007] According to the present disclosure, there is provided a porous carbon material that has a sufficient amount of wide voids, such as interparticle voids, and has good oxidation resistance, and is suitable as a catalyst support. Furthermore, according to the present disclosure, there is provided a method for producing the porous carbon material, which can easily produce the porous carbon material.

[0008] FIG. 1 is a diagram showing the pore distribution curve of the porous carbon material obtained in Example 1.

[0009] Preferred embodiments of the present disclosure will be described in detail below.

[0010] (Porous Carbon Material) The porous carbon material of this embodiment is a carbon material having a plurality of pores.

[0011] The porous carbon material of this embodiment has a peak (hereinafter also referred to as a first peak) located in a pore diameter range of 3 nm or more and less than 10 nm in the pore diameter distribution measured by mercury intrusion porosimetry. １ ~A ２ "having a peak located in the range of pore diameter A １ ~A ２ This means that a peak having a peak top in the range of

[0012] The porous carbon material of this embodiment also has a nitrogen adsorption isotherm, which is characterized by a relative pressure (P / P ０ ) The difference between the amount of nitrogen adsorption at 0.99 and the amount of nitrogen adsorption at 0.98 is 110 cm ３ / g or more, and the nitrogen adsorption amount at a relative pressure of 0.07 is 150 cm ３ / g or less.

[0013] It can be said that the porous carbon material of this embodiment has the first group of pores forming the above-mentioned first peak.

[0014] In this embodiment, the difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 is 110 cm ３ / g or more means that there are sufficient wide voids, such as interparticle voids, in the porous carbon material. In addition, in this embodiment, the nitrogen adsorption amount at a relative pressure of 0.07 is 150 cm ３ / g or less means that there are few micropores in the porous carbon material.

[0015] The porous carbon material of this embodiment has a low tap density and sufficient wide voids, such as interparticle voids, allowing for efficient transport of reactant substrates to reaction sites and efficient discharge of reaction products. Furthermore, the porous carbon material of this embodiment has a first group of pores, allowing for efficient loading of an active metal within the first group of pores. Furthermore, since this embodiment has the wide voids and the first group of pores, the porous carbon material can be coated with a coating material without poisoning or burying the active metal loaded within the first group of pores. Thus, the porous carbon material of this embodiment allows reactant substrates to easily reach the reaction sites, and the reaction sites can function effectively even when coated with a coating material. Therefore, the porous carbon material of this embodiment can be suitably used as a catalyst support (e.g., a catalyst support for a fuel cell).

[0016] Furthermore, it is believed that the excellent oxidation resistance of the porous carbon material of this embodiment is realized by having a small number of fine pores (micropores) that are likely to become the starting points of deterioration. Furthermore, if a large number of fine pores (micropores) are present, reactants may be adsorbed into the pores, hindering the transport of the reactants (transport of reaction substrates to reaction sites, and discharge of products out of the system). In the porous carbon material of this embodiment, the small number of fine pores (micropores) suppresses the adsorption of reactants (e.g., water) into the pores, resulting in excellent reactant transportability. From this perspective, the porous carbon material of this embodiment can also be suitably used as a catalyst support (e.g., a catalyst support for a fuel cell).

[0017] The first peak is located in the pore diameter range of 3 nm or more and less than 10 nm, and preferably in the pore diameter range of 4 nm or more and 7 nm or less, whereby the above-mentioned effect is more significantly exhibited.

[0018] The peak value of the first peak may be, for example, 0.1 mL / g or more, or 0.5 mL / g or more. The peak value of the first peak may be, for example, 4 mL / g or less, or 2 mL / g or less. That is, the peak value of the first peak may be, for example, 0.1 to 4 mL / g, 0.1 to 2 mL / g, 0.5 to 4 mL / g, or 0.5 to 2 mL / g.

[0019] The porous carbon material of this embodiment may further have a peak (hereinafter also referred to as a second peak) located in a pore size range of 10 nm to 1 μm in the pore size distribution measured by mercury intrusion porosimetry. That is, the porous carbon material of this embodiment may have a second pore group forming the second peak.

[0020] It is believed that when the porous carbon material of this embodiment has a second peak, the reactant can move efficiently through the second group of pores, the reactant can be efficiently transported to the reaction site, and the reaction product can be efficiently discharged.

[0021] The second peak is located in the pore diameter range of 10 nm to 1 μm, and preferably in the pore diameter range of 20 nm to 200 nm, whereby the above-mentioned effect is more pronounced.

[0022] The peak value of the second peak may be, for example, 0.1 mL / g or more, or 0.5 mL / g or more. The peak value of the second peak may be, for example, 6 mL / g or less, or 4 mL / g or less. That is, the peak value of the second peak may be, for example, 0.1 to 6 mL / g, 0.1 to 4 mL / g, 0.5 to 6 mL / g, or 0.5 to 4 mL / g.

[0023] When the porous carbon material of this embodiment has a first peak and a second peak, the first peak and the second peak are preferably the peak with the highest peak value (Peak A) and the peak with the second highest peak value (Peak B) among the peaks located in the pore diameter range of 3 nm to 1 μm. That is, it is preferable that the first peak is Peak A and the second peak is Peak B, or that the first peak is Peak B and the second peak is Peak A.

[0024] In this specification, the pore size distribution of the porous carbon material is measured by mercury intrusion porosimetry. More specifically, it is measured by the following method. The pore size distribution is represented by a pore size distribution curve with the horizontal axis representing the pore size (pore diameter) (logarithmic scale) and the vertical axis representing the log differential pore volume (linear scale). <Measurement of Pore Size Distribution> First, 40 to 80 mg of the porous carbon material is collected in a 5 cc measurement cell. Next, using an automatic mercury porosimeter (Shimadzu Corporation-Micromeritics Autopore V9620), the mercury pressure is increased from 1 psia to 60,000 psia, and the amount of mercury intrusion is measured. The pore size distribution is then determined from the obtained pressure vs. intrusion amount curve. The mercury contact angle is 130 degrees, and the mercury surface tension is 485 dynes / cm.

[0025] The difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 is 110 cm ３ / g or more, and from the viewpoint of obtaining the above-mentioned effects more effectively, 130 cm ３ / g or more, 150cm ３ / g or more, 170cm ３ / g or more, or 180 cm ３ / g or more.

[0026] The difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 is, for example, 1500 cm ３ / g or less, and from the viewpoint of improving the mobility of the substrate due to the presence of voids of an appropriate size, 1300 cm ３ / g or less, 1100cm ３ / g or less or 1000 cm ３ / g or less.

[0027] That is, the difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 is, for example, 110 to 1500 cm ３ / g, 110-1300cm ３ / g, 110-1100cm ３ / g, 110-1000cm ３ / g, 130-1500cm ３ / g, 130-1300cm ３ / g, 130-1100cm３ / g, 130-1000cm ３ / g, 150-1500cm ３ / g, 150-1300cm ３ / g, 150-1100cm ３ / g, 150-1000cm ３ / g, 170-1500cm ３ / g, 170-1300cm ３ / g, 170-1100cm ３ / g, 170-1000cm ３ / g, 180-1500cm ３ / g, 180-1300cm ３ / g, 180-1100cm ３ / g, or 180 to 1000 cm ３ / g.

[0028] The amount of nitrogen adsorption at a relative pressure of 0.07 is 150 cm ３ / g or less, and from the viewpoint of obtaining the above-mentioned effect more significantly, 140 cm ３ / g or less, 130cm ３ / g or less, or 120 cm ３ / g or less.

[0029] The amount of nitrogen adsorption at a relative pressure of 0.07 is, for example, 10 cm ３ / g or more, and from the viewpoint that the catalyst is easily supported due to the presence of fine pores, ３ / g or more, 50cm ３ / g or more, 70cm ３ / g or more, or 90 cm ３ / g or more.

[0030] That is, the amount of nitrogen adsorption at a relative pressure of 0.07 is, for example, 10 to 150 cm ３ / g, 10-140cm ３ / g, 10-130cm ３ / g, 10-120cm ３ / g, 10-150cm ３ / g, 30-140cm ３ / g, 30-130cm ３ / g, 30-120cm ３ / g, 50-150cm ３ / g, 50-140cm ３ / g, 50-130cm ３ / g, 50-120cm ３ / g, 70-150cm ３ / g, 70-140cm ３ / g, 70-130cm ３ / g, 70-120cm ３ / g, 90-150cm ３ / g, 90-140cm ３ / g, 90-130cm ３ / g, or 90 to 120 cm ３ / g.

[0031] The amount of nitrogen adsorption in the nitrogen adsorption isotherm (N １ ) and the nitrogen adsorption amount (N ２ ) and the difference (N １ -N ２ ) at any relative pressure between 0.90 and 0.99 (i.e., in the entire range of relative pressure between 0.90 and 0.99), ３ / g or less. １ -N ２ ) is small, both the transport of the reaction substrate into the porous carbon material and the discharge of the reaction product from the porous carbon material proceed efficiently, and the decrease in the 5% weight loss temperature is suppressed, so it can be said that the porous carbon material is more suitable as a catalyst support.

[0032] The difference (N １ -N ２ ) is 140 cm at any relative pressure between 0.90 and 0.99, from the viewpoint of more significantly exhibiting the above effect. ３ / g or less, 120cm ３ / g or less, 100cm ３ / g or less, 80cm ３ / g or less, or 60 cm ３ / g or less.

[0033] The difference (N １ -N ２ ) is, for example, 0.1 cm at any relative pressure between 0.90 and 0.99 in order to reduce the tap density. ３ / g or more, 0.5cm３ / g or more, 5cm ３ / g or more, 10cm ３ / g or more, 30cm ３ / g or more, or 50 cm ３ / g or more.

[0034] That is, at any relative pressure between 0.90 and 0.99, the difference (N １ -N ２ ) is, for example, 0.1 to 150 cm ３ / g, 0.1 to 140 cm ３ / g, 0.1 to 120 cm ３ / g, 0.1 to 100 cm ３ / g, 0.1 to 80 cm ３ / g, 0.1 to 60 cm ３ / g, 0.5 to 150 cm ３ / g, 0.5 to 140 cm ３ / g, 0.5 to 120 cm ３ / g, 0.5 to 100 cm ３ / g, 0.5 to 80 cm ３ / g, or 0.5 to 60 cm ３ / g.

[0035] The amount of nitrogen adsorption in the nitrogen adsorption isotherm (N １ ) and the nitrogen adsorption amount (N ２ ) and the difference (N １ -N ２ ) is 150 cm at any relative pressure between 0 and 0.99. ３ / g or less. １ -N ２ ) is small, the transport of the reaction substrate into the porous carbon material and the discharge of the reaction product from the porous carbon material both proceed efficiently, making it more suitable as a catalyst support.

[0036] The difference (N １ -N ２ ) is 140 cm at any relative pressure between 0 and 0.99, from the viewpoint of more significantly exhibiting the above effect. ３ / g or less, 120cm ３ / g or less, 100cm ３ / g or less, 80cm３ / g or less, or 60 cm ３ / g or less.

[0037] The difference (N １ -N ２ ) is, for example, 0.1 cm at any relative pressure from 0 to 0.99 in order to reduce the tap density. ３ / g or more, 0.5cm ３ / g or more, 5cm ３ / g or more, 10cm ３ / g or more, 30cm ３ / g or more, or 50 cm ３ / g or more.

[0038] That is, at any relative pressure between 0 and 0.99, the difference (N １ -N ２ ) is, for example, 0.1 to 150 cm ３ / g, 0.1 to 140 cm ３ / g, 0.1 to 120 cm ３ / g, 0.1 to 100 cm ３ / g, 0.1 to 80 cm ３ / g, 0.1 to 60 cm ３ / g, 0.5 to 150 cm ３ / g, 0.5 to 140 cm ３ / g, 0.5 to 120 cm ３ / g, 0.5 to 100 cm ３ / g, 0.5 to 80 cm ３ / g, or 0.5 to 60 cm ３ / g.

[0039] In this specification, the nitrogen adsorption amount of a porous carbon material is measured by the following method. <Measurement of nitrogen adsorption amount> A porous carbon material is dried under vacuum at 300°C for 3 hours using a pretreatment device (BELPREP-VAC II manufactured by Microtrac-Bell). Next, a nitrogen adsorption isotherm and a nitrogen desorption isotherm are measured using a high-precision gas / vapor adsorption amount measuring device (BELSORP MAX II manufactured by Microtrac-Bell). Then, the nitrogen adsorption amount at a predetermined relative pressure is calculated from the obtained nitrogen adsorption isotherm or nitrogen desorption isotherm.

[0040] The specific surface area of ​​the porous carbon material of this embodiment is, for example, 200 m ２ / g or more, and ２ / g or more, 300m ２ / g or more, 350m ２ / g or more, 400m ２ / g or more or 450m ２ / g or more. This improves the dispersibility of the active metal on the porous carbon material when the active metal is supported, and reaction sites tend to be formed more efficiently. The specific surface area of ​​the porous carbon material of this embodiment may be, for example, 1800 m ２ / g or less, and ２ / g or less, 1000m ２ / g or less, 700m ２ / g or less, or 500m ２ / g or less. This tends to further improve the strength of the porous structure of the porous carbon material. That is, the specific surface area of ​​the porous carbon material of this embodiment may be, for example, 200 to 1800 m ２ / g, 200-1500m ２ / g, 200-1000m ２ / g, 200-700m ２ / g, 200-500m ２ / g, 250-1800m ２ / g, 250-1500m ２ / g, 250-1000m ２ / g, 250-700m ２ / g, 250-500m ２ / g, 300-1800m ２ / g, 300-1500m ２ / g, 300-1000m ２ / g, 300-700m ２ / g, 300-500m ２ / g, 350-1800m ２ / g, 350-1500m ２ / g, 350-1000m ２ / g, 350-700m ２ / g, 350-500m ２ / g, 400-1800m ２ / g, 400-1500m ２ / g, 400-1000m２ / g, 400-700m ２ / g, 400-500m ２ / g, 450-1800m ２ / g, 450-1500m ２ / g, 450-1000m ２ / g, 450-700m ２ / g, or 450 to 500 m ２ / g.

[0041] In this specification, the specific surface area of ​​a porous carbon material refers to a value measured by a nitrogen adsorption method. More specifically, it is measured by the following method in accordance with JIS Z8830. <Measurement of specific surface area> A porous carbon material is dried under vacuum at 300°C for 3 hours using a pretreatment device (BELPREP-VAC II, manufactured by Microtrac-Bell). Next, a nitrogen adsorption isotherm is measured using an automatic specific surface area measuring device (BELSORP MAX II, manufactured by Microtrac-Bell). Then, the specific surface area is calculated from the obtained nitrogen adsorption isotherm using the BET method.

[0042] The tap density of the porous carbon material of this embodiment may be, for example, 0.28 g / mL or less, 0.20 g / mL or less, or 0.15 g / mL or less. This tends to result in the presence of many wide voids, such as interparticle voids, which facilitates the movement of reaction substrates and the discharge of products. The tap density of the porous carbon material of this embodiment may be, for example, 0.01 g / mL or more, 0.04 g / mL or more, 0.08 g / mL or more, or 0.12 g / mL or more. This tends to prevent the porous carbon material from being excessively pulverized, thereby suppressing aggregation. That is, the tap density of the porous carbon material of the present embodiment may be, for example, 0.01 to 0.28 g / mL, 0.01 to 0.20 g / mL, 0.01 to 0.15 g / mL, 0.04 to 0.28 g / mL, 0.04 to 0.20 g / mL, 0.04 to 0.15 g / mL, 0.08 to 0.28 g / mL, 0.08 to 0.20 g / mL, 0.08 to 0.15 g / mL, 0.12 to 0.28 g / mL, 0.12 to 0.20 g / mL, or 0.12 to 0.15 g / mL.

[0043] The porous carbon material of this embodiment may include, for example, a fired product of a resin material. The porous carbon material of this embodiment may be, for example, a fired product of a resin molded body containing a resin material. The porous carbon material of this embodiment may be, for example, a pulverized product obtained by pulverizing the fired product.

[0044] Any resin material may be used as long as it can form amorphous carbon upon firing. Examples of the resin material include phenolic resins (novolac-type phenolic resins, resol-type phenolic resins), furan resins, epoxy resins, unsaturated polyester resins, ester resins, urea resins, melamine resins, alkyd resins, xylene resins, polyurethane resins, polyuric acid resins, acrylonitrile resins, polystyrene resins, bismaleimide-triazine resins, divinylbenzene resins, polyimide resins, diallyl phthalate resins, and vinyl ester resins.

[0045] As the resin material, a polymer of a phenol and formaldehyde can be suitably used.

[0046] Phenols are compounds in which at least one hydroxy group is bonded to an aromatic ring. Examples of phenols include phenol, o-cresol, m-cresol, p-cresol, dihydroxybenzene (1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), 1,4-dihydroxybenzene (hydroquinone)), 5-methylresorcinol (orcinol), urushiol, pyrogallol, phloroglucinol, hydroxyhydroquinone, hydroxynaphthalene, hydroxyanthracene, hydroxypyridine, and furfuryl alcohol. Preferred phenols are phenol, resorcinol, phloroglucinol, 1,5-dihydroxynaphthalene, and furfuryl alcohol, with resorcinol being more preferred. One type of phenol may be used alone, or two or more types may be used in combination.

[0047] The polymer may be one obtained by reacting a phenol with formaldehyde, or one obtained by reacting a phenol with a polymer of formaldehyde (for example, paraformaldehyde).

[0048] The polymer may be a polymer produced by an acid catalyst or a polymer produced by a base catalyst, but is preferably a polymer produced by an acid catalyst.

[0049] The fired resin material may be any material obtained by firing the resin material under conditions that form amorphous carbon. By appropriately changing the firing conditions and pulverization conditions as described below, a porous carbon material having the above-mentioned properties can be obtained.

[0050] The porous carbon material of this embodiment can be produced, for example, by the following production method.

[0051] (Method for producing porous carbon material) The method for producing a porous carbon material of this embodiment includes a preparation step of preparing a resin molded body containing a resin material as a carbon source and a mesopore-forming template, a firing step of firing the resin molded body to obtain a fired body, and a crushing step of crushing the fired body to obtain a porous carbon material.

[0052] In this embodiment, the calcination step is carried out in such a manner that the nitrogen adsorption amount at a relative pressure of 0.07 in the nitrogen adsorption isotherm of the porous carbon material is 150 cm ３ The pulverization step is a step of firing the resin molded body so that the carbon density is 110 cm / g or less. ３ The fired body is then pulverized to a powder of 1 / g or more.

[0053] According to the method for producing a porous carbon material of the present embodiment, by using a mesopore-forming template and controlling the firing step and the pulverization step based on the nitrogen adsorption isotherm of the carbonaceous carbon material, it is possible to easily produce a porous carbon material that has the above-mentioned good oxidation resistance and is suitable as a catalyst support.

[0054] Each step of the manufacturing method of this embodiment will be described in detail below.

[0055] In the preparation step, a resin molded body containing a resin material serving as a carbon source and a mesopore-forming template is prepared.

[0056] The resin material may be any material that can form amorphous carbon by firing. Examples of the resin material include the same materials as those mentioned above.

[0057] The mesopore-forming template may be any template capable of forming the first group of pores forming the first peak, and may contain, for example, amphiphilic molecules.

[0058] The amphiphilic molecule is preferably a molecule capable of forming micelles in water, and the micelles formed by such amphiphilic molecules can be dispersed in a resin material to easily obtain a resin molded product containing the template.

[0059] Any known amphiphilic molecule capable of forming micelles in water can be used without any particular limitation as the amphiphilic molecule, including, for example, a diblock copolymer having a hydrophilic block-hydrophobic block structure, a triblock copolymer having a hydrophilic block-hydrophobic block-hydrophilic block structure, and a triblock copolymer having a hydrophobic block-hydrophilic block-hydrophobic block structure.

[0060] Examples of hydrophilic blocks include polyethylene oxide blocks, polyvinylpyridine blocks, and polymethyl methacrylate blocks. Of these, polyethylene oxide blocks are preferred. The number of ethylene oxide units in the polyethylene oxide block is preferably 20 to 150, and more preferably 90 to 120. That is, the number of ethylene oxide units in the polyethylene oxide block may be, for example, 20 to 150, 20 to 120, 90 to 150, or 90 to 120.

[0061] Examples of hydrophobic blocks include polypropylene oxide blocks, hydrocarbon blocks, and polystyrene blocks. Among these, polypropylene oxide blocks are preferred. The number of propylene oxide units in the polypropylene oxide block is preferably 30 to 100, and more preferably 60 to 80. That is, the number of propylene oxide units in the polypropylene oxide block may be, for example, 30 to 100, 30 to 80, 60 to 100, or 60 to 80.

[0062] The amphiphilic molecule is preferably a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.

[0063] In this embodiment, the pore diameter of the first pore group (i.e., the peak position of the first peak) can be adjusted by adjusting the particle size of the micelles formed by the amphiphilic molecules. In other words, the amphiphilic molecules may be capable of forming micelles that serve as templates (mesopore-forming templates) for forming a pore group (first pore group) having a pore diameter peak (first peak) located in the range of 3 nm or more and less than 10 nm.

[0064] In the preparation step, the amount of the mesopore-forming template may be, for example, 30 parts by mass or more, preferably 40 parts by mass or more, and more preferably 50 parts by mass or more, per 100 parts by mass of the resin material. Furthermore, in the preparation step, the amount of the mesopore-forming template may be, for example, 140 parts by mass or less, preferably 120 parts by mass or less, and more preferably 100 parts by mass or less, per 100 parts by mass of the resin material. That is, the amount of the mesopore-forming template in the preparation step may be, for example, 30 to 140 parts by mass, 30 to 120 parts by mass, 30 to 100 parts by mass, 40 to 140 parts by mass, 40 to 120 parts by mass, 40 to 100 parts by mass, 50 to 140 parts by mass, 50 to 120 parts by mass, or 50 to 100 parts by mass, per 100 parts by mass of the resin material.

[0065] By adjusting the amount of the mesopore-forming template, the proportion of pores having a pore diameter of 3 nm or more and less than 10 nm can be adjusted. That is, in this embodiment, the amount of the mesopore-forming template may be appropriately adjusted so that the proportion of pores having a pore diameter of 3 nm or more and less than 10 nm in the porous carbon material falls within a suitable range.

[0066] In a preferred embodiment, the preparation step may include a resin material formation step of forming a resin material in a dispersion containing micelles formed by amphiphilic molecules and an aqueous solvent to obtain a precipitate containing the micelles and the resin material, and a drying step of drying the precipitate to obtain a resin molded product containing the resin material and the amphiphilic molecules.

[0067] In the resin material formation step, for example, the resin material may be formed from a precursor of the resin material in a dispersion liquid. Here, the precursor of the resin material may be, for example, a monomer that forms the resin material by polymerization, a polymer that forms the resin material by modification, or the like.

[0068] The aqueous solvent is a solvent containing water and may further contain an organic solvent that is compatible with water, such as alcohols such as methanol, ethanol, 1-propanol, and 2-propanol.

[0069] The resin material forming step may be, for example, a step of polymerizing a phenol and formaldehyde in a dispersion liquid to obtain a precipitate containing a polymer of the phenol and formaldehyde and micelles.

[0070] The polymerization of the phenol and formaldehyde may be carried out in the presence of a polymerization catalyst. The polymerization catalyst may be an acid catalyst or a base catalyst, with an acid catalyst being preferred. That is, the dispersion may contain a polymerization catalyst (an acid catalyst or a base catalyst), with an acid catalyst being preferred.

[0071] Examples of acid catalysts include hydrochloric acid, acetic acid, oxalic acid, sulfonic acid, etc. Examples of base catalysts include sodium hydroxide, ammonia, amines, etc.

[0072] Amount C of phenols provided in dispersion １(mol) and the amount of formaldehyde C ２ (mol) C １ / C ２ may be, for example, 0.1 or more, and preferably 0.3 or more. １ / C ２ may be, for example, 1.0 or less, and is 0.9 or less. That is, the ratio C １ / C ２ may be, for example, 0.1 to 1.0, 0.1 to 0.9, 0.3 to 1.0, or 0.3 to 0.9.

[0073] The reaction conditions for the polymerization of phenols and formaldehyde are not particularly limited. For example, the reaction temperature may be 20 to 80° C., and the reaction time may be 10 minutes to 96 hours.

[0074] In the drying step, the precipitate is collected and the aqueous solvent is removed to obtain a resin molded product. The drying conditions in the drying step are not particularly limited, and the drying temperature may be, for example, 20 to 80°C.

[0075] The firing step is a step of firing the resin molded body to obtain a fired body.

[0076] The firing conditions in the firing step are not particularly limited as long as the resin material in the resin molded body can form amorphous carbon.

[0077] The firing conditions in the firing step may be adjusted as appropriate so that the amount of nitrogen adsorption at a relative pressure of 0.07 in the nitrogen adsorption isotherm of the porous carbon material falls within a suitable range.

[0078] The firing temperature in the firing step may be, for example, 1100 to 3000° C., or 2000 to 2500° C. Increasing the firing temperature tends to decrease the amount of nitrogen adsorption at the relative pressure of 0.07, while decreasing the firing temperature tends to increase the amount of nitrogen adsorption at the relative pressure of 0.07.

[0079] The firing in the firing step is preferably carried out in an inert gas atmosphere (for example, in a nitrogen atmosphere or an argon atmosphere).

[0080] The calcination step may include an activation step in which the material is calcined in an inert gas atmosphere and then heated in air. The heating conditions in the activation step are not particularly limited, and for example, the heating temperature may be 400 to 800°C and the heating time may be 1 minute to 1 hour. The activation step can increase the specific surface area of ​​the porous carbon material. The activation step can also adjust the nitrogen adsorption amount at the above-mentioned relative pressure of 0.07.

[0081] The pulverization step is a step in which the fired body is pulverized to obtain a porous carbon material.

[0082] The pulverization method is not particularly limited, but it is preferable to combine coarse pulverization and fine pulverization. Examples of the coarse pulverization method include pulverization using a mortar, pulverization using a mortar mill, pulverization using a stamp mill, etc. Examples of the fine pulverization method include pulverization using a media stirring mill, pulverization using a container-driven mill, pulverization using a high-speed rotary pulverizer, etc.

[0083] In the pulverization step, the difference between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98 in the nitrogen adsorption isotherm of the porous carbon material was 110 cm ３ That is, the pulverization conditions in the pulverization step may be appropriately adjusted so that the difference between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98 falls within a suitable range.

[0084] In addition, whether the pulverization is insufficient or excessive, the difference between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98 tends to be small. In this embodiment, appropriate pulverization conditions can be set using the difference between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98 as an index.

[0085] The use of the porous carbon material of this embodiment is not particularly limited, and it can be used for known uses of carbon materials without particular limitation.

[0086] The porous carbon material of this embodiment can allow the reaction sites to function effectively even when coated with a coating material, and therefore can be particularly suitably used in applications where the material is coated with a coating material.

[0087] For example, the porous carbon material of this embodiment can be suitably used as a cathode catalyst support for a polymer electrolyte fuel cell. A cathode catalyst is used by supporting an active metal (e.g., platinum) on the porous carbon material and coating it with an ionomer. According to the porous carbon material of this embodiment, the active metal supported inside the first group of pores can fully exhibit catalytic activity without being poisoned by the ionomer.

[0088] The porous carbon material of this embodiment can also be suitably used as an electrode material for capacitors, an electrode material for secondary batteries, a gas adsorption material, and the like.

[0089] The porous carbon material of this embodiment has excellent oxidation resistance. The oxidation resistance can be evaluated, for example, by the 5% weight loss temperature. The 5% weight loss temperature of the porous carbon material of this embodiment may be, for example, 500°C or higher, or may be 520°C or higher, 540°C or higher, 560°C or higher, 565°C or higher, 570°C or higher, 580°C or higher, or 600°C or higher.

[0090] In this specification, the 5% weight loss temperature of a porous carbon material is measured by the following method. <Measurement of 5% weight loss temperature> After weighing out about 5 mg of a porous carbon material, the sample is placed in a thermogravimetric / differential calorimeter (STA2500 manufactured by NETZSCH), and the weight loss is measured from 25°C to 1000°C under a heating rate of 10°C / min and an air flow of 20 mL / min. The weight at 25°C on the obtained weight curve is taken as 100%, and the temperature at which 5% weight loss occurs is taken as the 5% weight loss temperature.

[0091] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

[0092] The present disclosure will be described in more detail below, but the present disclosure is not limited to these examples.

[0093] Example 1 6.4 parts by mass of resorcinol, 0.8 parts by mass of 5 mol / L hydrochloric acid, 10.0 parts by mass of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (Pluronic F127 manufactured by Sigma-Aldrich), 31.9 parts by mass of ethanol, and 40.0 parts by mass of ultrapure water were mixed, and then 10.9 parts by mass of formaldehyde solution (formaldehyde content: 37% by mass) was added to prepare a dispersion. This dispersion was stirred at 25°C for 72 hours to obtain a precipitate. This precipitate was dried at 70°C for 48 hours to obtain a resin molded body. This resin molded body was heated to 900°C at a rate of 1.5°C / min under a nitrogen atmosphere and then maintained at 900°C for 3 hours to obtain a porous carbon material. The obtained porous carbon material was pulverized in a mortar and further pulverized in a wet bead mill for 60 minutes. The pulverized porous carbon material was heated to 2100° C. at a rate of 10° C. / min in an argon atmosphere, and then held at 2100° C. for 1 hour to obtain a powdered porous carbon material.

[0094] Example 2 A porous carbon material was produced in the same manner as in Example 1, except that the firing temperature was changed from 2100°C to 1800°C.

[0095] Example 3 A porous carbon material was produced in the same manner as in Example 1, except that the treatment time in the bead mill was changed from 60 minutes to 40 minutes.

[0096] Comparative Example 1 A porous carbon material was produced in the same manner as in Example 1, except that the firing temperature was changed from 2100° C. to 900° C. and the treatment using a bead mill was not carried out.

[0097] Comparative Example 2 A porous carbon material was produced in the same manner as in Example 1, except that the treatment using a bead mill was not carried out.

[0098] Comparative Example 3 A porous carbon material was produced in the same manner as in Example 1, except that the firing temperature was changed from 2100° C. to 900° C. and the treatment time in the bead mill was changed from 60 minutes to 120 minutes.

[0099] Comparative Example 4 A porous carbon material was produced in the same manner as in Example 1, except that the firing temperature was changed from 2100°C to 900°C.

[0100] The porous carbon materials produced in the examples and comparative examples were measured and evaluated by the following methods.

[0101] <Measurement of pore size distribution by mercury intrusion porosimetry> 40 to 80 mg of porous carbon material was collected in a 5 cc measurement cell. Next, using an automatic mercury porosimeter (Shimadzu Corporation-Micromeritics, Autopore V9620), the mercury pressure was increased from 1 psia to 60,000 psia, and the amount of mercury intrusion was measured. The pore size distribution was then determined from the obtained curve of pressure and intrusion amount. The mercury contact angle was 130 degrees, and the mercury surface tension was 485 dynes / cm. The positions of the first and second peaks in the obtained pore size distribution were determined and are listed in Tables 1 and 2. Note that FIG. 1 shows the pore size distribution curve of the porous carbon material obtained in Example 1.

[0102] <Measurement of nitrogen adsorption amount> The porous carbon material was dried under vacuum at 300°C for 3 hours using a pretreatment device (BELPREP-VAC II manufactured by Microtrac-Bell). Next, a high-precision gas / vapor adsorption amount measuring device (BELSORP MAX II manufactured by Microtrac-Bell) was used to measure the nitrogen adsorption isotherm and nitrogen desorption isotherm. From the measurement results of the nitrogen adsorption isotherm, the relative pressure (P / P ０ ) is between 0.98 and 0.99 Ａ ), relative pressure (P / P ０ ) is between 0 and 0.07. Ｂ The results are shown in Tables 1 and 2. From the results of measuring the nitrogen adsorption isotherm and nitrogen desorption isotherm, any relative pressure (P / P) between 0.90 and 0.99 was obtained. ０ ) The maximum difference between the nitrogen adsorption amount of the nitrogen adsorption isotherm and the nitrogen desorption isotherm (N Ｘ The results are shown in Tables 1 and 2.

[0103] <Measurement of specific surface area> The porous carbon material was dried under vacuum at 300°C for 3 hours using a pretreatment device (BELPREP-VAC II manufactured by Microtrac-Bell). Next, a nitrogen adsorption isotherm was measured using a high-precision gas / vapor adsorption measurement device (BELSORP MAX II manufactured by Microtrac-Bell). The specific surface area was then calculated from the obtained nitrogen adsorption isotherm using the BET method. The calculated specific surface areas are shown in Tables 1 and 2.

[0104] <Evaluation of Oxidation Resistance> The oxidation resistance of the porous carbon material was evaluated by measuring the 5% weight loss temperature. The higher the 5% weight loss temperature, the better the oxidation resistance. The 5% weight loss temperature was measured using the following method. The results are shown in Tables 1 and 2. <Measurement of 5% Weight Loss Temperature> Approximately 5 mg of the porous carbon material was weighed out, and the sample was placed in a thermogravimetric / differential calorimeter (STA2500, manufactured by NETZSCH). The weight loss was measured from 25°C to 1000°C at a heating rate of 10°C / min and an air flow of 20 mL / min. The weight at 25°C in the obtained weight curve was taken as 100%, and the temperature at which 5% weight loss occurred was taken as the 5% weight loss temperature.

[0105] <Measurement of tap density> Measurement was carried out according to JIS K1469 by the following method. A porous carbon material was poured into a 100 mL measuring cylinder up to the 100 mL mark. A rubber stopper was fitted to the measuring cylinder, and the sample was allowed to drop naturally from a height of 5 cm onto a rubber plate 50 times, after which the volume of the sample was read. The weight of the measured porous carbon material was divided by the read volume of the porous carbon material to calculate the tap density.

[0106]

[0107]

[0108] Relative pressure (P / P ０ ) is the difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 (N Ａ ) is 110 cm ３ In Examples 1 to 3, where the tap density was 1 / g or more, it was confirmed that there were many large voids such as interparticle voids due to the small tap density. ０The nitrogen adsorption amount (N Ｂ ) is 150 cm ３ In Examples 1 to 3, where the 5% weight loss temperature was 1 / g or more, it was confirmed that the alloys had excellent oxidation resistance, based on their high 5% weight loss temperatures.

[0109] In Comparative Examples 1 and 2, the relative pressure (P / P ０ ) is the difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 (N Ａ ) and the tap density is high, it is thought that wide voids such as interparticle voids are not sufficiently formed. ０ The nitrogen adsorption amount (N Ｂ ) and a low 5% weight loss temperature, it is believed that the presence of many fine pores in the porous carbon material results in poor oxidation resistance.

[0110] <Measurement of Water Vapor Adsorption Amount> The water vapor adsorption amounts of the porous carbon materials of Example 1 and Comparative Example 4 were measured by the following method. First, the porous carbon material was dried under vacuum at 300°C for 3 hours using a pretreatment device (BELPREP-VAC II manufactured by Microtrac-Bel). Next, the water vapor adsorption isotherm of the sample was measured using a high-precision gas / vapor adsorption amount measurement device (BELSORP MAX II manufactured by Microtrac-Bel), and the water vapor adsorption amount at a relative pressure of 0.9 was read. The results are shown in Table 3.

[0111]

[0112] The results in Table 3 confirm that the porous carbon material of Example 1 has less water adsorption within the porous carbon material than the porous carbon material of Comparative Example 4, and is suitable as a catalyst support, in which transportability of reactants is one of the important factors.

Claims

1. In the pore size distribution measured by mercury intrusion porosimetry, the pore size peak is in the range of 3 nm to less than 10 nm, and in the nitrogen adsorption isotherm, the difference between the amount of nitrogen adsorption at a relative pressure of 0.99 and the amount of nitrogen adsorption at a relative pressure of 0.98 is 110 cm ３ / g or more, and the nitrogen adsorption amount at a relative pressure of 0.07 is 150 cm ３ / g or less.

2. At any relative pressure between 0.90 and 0.99, the difference between the amount of nitrogen adsorbed in the nitrogen adsorption isotherm and the amount of nitrogen adsorbed in the nitrogen desorption isotherm is 150 cm ３ The porous carbon material according to claim 1, wherein the molecular weight of the porous carbon material is 1 / g or less.

3. At any relative pressure between 0.90 and 0.99, the difference between the amount of nitrogen adsorbed in the nitrogen adsorption isotherm and the amount of nitrogen adsorbed in the nitrogen desorption isotherm is 140 cm ３ The porous carbon material according to claim 2, wherein the molecular weight of the porous carbon material is 1 / g or less.

4. At any relative pressure between 0 and 0.99, the difference between the amount of nitrogen adsorbed in the nitrogen adsorption isotherm and the amount of nitrogen adsorbed in the nitrogen desorption isotherm is 150 cm ３ The porous carbon material according to claim 1 or 2, wherein the molecular weight is 1 / g or less.

5. A method for producing a porous carbon material, comprising: a preparation step of preparing a resin molded body containing a resin material as a carbon source and a mesopore-forming template; a firing step of firing the resin molded body to obtain a fired body; and a pulverization step of pulverizing the fired body to obtain a porous carbon material, wherein the firing step is carried out to obtain a porous carbon material having a nitrogen adsorption isotherm of 150 cm at a relative pressure of 0.

07. ３ / g or less, and the pulverization step is a step of pulverizing the resin molded body so that the difference between the nitrogen adsorption amount at a relative pressure of 0.99 and the nitrogen adsorption amount at a relative pressure of 0.98 in a nitrogen adsorption isotherm of the porous carbon material is 110 cm ３ and pulverizing the fired body so that the sintered body has a porosity of 1 / g or more.

6. The method according to claim 5, wherein the mesopore-forming template comprises an amphiphilic molecule.

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