TW201545893A - Porous carbon sheet - Google Patents

Abstract

The purpose of the present invention is to provide a porous carbon sheet which is able to achieve improved corrosion resistance, while having improved heat resistance. A porous carbon sheet which is characterized by being composed of a binder and a porous carbon powder that has mesopores irregularly arranged in a carbonaceous wall, with adjacent mesopores communicating each other. It is preferable that the ratio of the binder to the porous carbon powder is from 5% by weight to 50% by weight (inclusive). It is also preferable that the porous carbon sheet has a thickness of from 250 [mu]m to 1,000 [mu]m (inclusive).

Description

Porous carbon flakes

The present invention relates to porous carbon flakes.

For the sheet used for the gas filter, the gas diffusion layer, the spacer, the catalyst carrier, the electrode, or the condenser, various materials such as metal or ceramic can be used. When it is used for such a use, there is a case where heat resistance or corrosion resistance (oxidation resistance) is required depending on the place of use or the like.

As an example of the use of the above-mentioned sheet, a proposal has been made to combine a plurality of metal foil layers into a condenser (Patent Document 1 below).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-86060

However, since the sheet shown in the above Patent Document 1 is gold Since it is used under the strict conditions of high temperature, high humidity, etc., there is a problem of so-called corrosion.

Accordingly, it is an object of the present invention to provide a porous carbon flake which can improve corrosion resistance while improving heat resistance.

In order to achieve the above object, the present invention is characterized in that a porous carbon powder and a binder are provided, and the porous carbon powder has a mesoporous hole, and adjacent mesopores communicate with each other.

According to the present invention, it is possible to exhibit an excellent effect of improving corrosion resistance and improving heat resistance.

1‧‧‧Polyuric acid resin

2‧‧‧Magnesium oxide

3‧‧‧carbon wall

4‧‧‧Pore

5‧‧‧Porous carbon

11‧‧‧Cylinder

12‧‧‧ Sealing body

13‧‧‧N ₂ gas introduction tube

14‧‧‧ Weight measuring platform

15‧‧‧heater

16‧‧‧N ₂ gas discharge pipe

21‧‧‧Sheet

22‧‧‧ water droplets

Fig. 1 is a view showing a manufacturing step of porous carbon used in the present invention, and Fig. 1(a) is an explanatory view showing a state in which a polyamic acid resin and magnesium oxide are mixed, and Fig. 1(b) is a view showing An explanatory view of a state after heat treatment of the mixture, and Fig. 2(c) is an explanatory view showing porous carbon.

Fig. 2 is a graph showing the results of thermogravimetric analysis in an air environment among sheets A1, A2, Z and porous carbon.

Fig. 3 is an explanatory view of a device for measuring the change in weight of each sheet by alternately flowing dry N ₂ and wet N ₂ among the sheets A1, A2, and Z.

Fig. 4 is a graph showing the response of the sheet A1 to environmental humidity.

Fig. 5 is a graph showing the response of the sheet Z to environmental humidity.

Fig. 6 is a photograph showing a state in which water droplets of water droplets on the sheet A1 are dropped.

Fig. 7 is a photograph showing a state of water droplets after 10 seconds from the dropping of water droplets on the sheet A1.

Fig. 8 is a photograph showing a state in which water droplets of water droplets on the sheet Z are dropped.

Fig. 9 is a photograph showing a state of water droplets after 10 seconds from the dropping of water droplets on the sheet Z.

Fig. 10 is a SEM image of porous carbon used for the sheet A1.

Fig. 11 is a photograph when an external force is applied to the sheet A1 in the bending direction.

Fig. 12 is a graph showing a pore distribution curve of the sheets A1 and Z.

[Best Mode for Carrying Out the Invention]

The present invention is composed of a porous carbon powder and a binder, wherein the porous carbon powder has a mesoporous hole, and the adjacent mesopores are in communication with each other.

Since the sheet having such a structure can improve the corrosion resistance and improve the heat resistance, it is most suitable for use in filters and intervals used at a certain high temperature (about 300 to 500 ° C) and in an oxidizing environment. Things and so on. Specifically, the advantages of the present invention will be described by taking the case of using as a gas filter as an example.

Since the metal filter has poor corrosion resistance, it is corroded and deforms at a high temperature (about 300 ° C or higher), and the shape cannot be maintained. Therefore, the function as a filter cannot be sufficiently exhibited. In addition, the filter made of the ceramics has a low alkali resistance and is likely to be dissolved in the presence of a vapor such as ammonia, and the porous material such as a ruthenium gel is at a high temperature (about 300 ° C). The structure will be destroyed, so the function as a filter cannot be fully utilized. Further, in the case of the filter using the activated carbon sheet, since the activated carbon is burned at about 300 ° C, it cannot be used at a high temperature. In contrast, the filter using the sheet of the present invention is excellent in corrosion resistance and heat resistance, and has a medium hole. Therefore, even when it is used under severe conditions (for example, in an environment of 300 ° C or higher and high humidity), there is no possibility of oxidation or combustion, and the function as a filter can be sufficiently exerted.

Further, the sheet of the present invention can be most suitably used even in the case of a catalyst carrier or a gas diffusion layer of a fuel cell whose temperature rises to about 300 °C. For example, when a catalyst carrier as a fuel cell is used, the wettability of the sheet of the present invention is excellent compared to the activated carbon sheet, and the following effects can be exhibited. When an activated carbon flake is used as the catalyst carrier of the above fuel cell, since the wettability of the activated carbon flake is poor, a film of water is formed on the surface of the flake. Therefore, since the platinum of the catalyst is hard to come into contact with the O ₂ gas, the catalyst capacity cannot be sufficiently exerted. On the other hand, when the sheet of the present invention is used in a catalyst carrier of a fuel cell, since the wettability of the sheet of the present invention is excellent, a film which forms water on the surface of the sheet can be suppressed. Therefore, since the platinum of the catalyst can be easily contacted with the O ₂ gas, the catalyst capability can be sufficiently exerted.

Further, since the present invention has a sheet shape and can suppress dusting or the like, the operation becomes easy. Moreover, since the sheet of the present invention has flexibility, workability is excellent when assembling parts, collecting parts, and the like.

In the present specification, the term "medium hole" means a hole having a pore diameter of 2 nm or more and 50 nm or less, and "microporous" means a hole of less than 2 nm.

The ratio of the binder to the porous carbon powder is preferably 5% by weight or more and 50% by weight or less.

If the above ratio is less than 5% by weight, there is a case where dust or shape collapses. On the other hand, when the ratio exceeds 50% by weight, the adhesive becomes a main material, so that the flexibility is lowered.

The film thickness is preferably 250 μm or more and 1000 μm or less. When the film thickness is less than 250 μm, the shape of the autonomous sheet cannot be maintained. On the other hand, when the film thickness exceeds 1000 μm, the flexibility may be lowered.

The binder is preferably a binder containing nitrogen and/or fluorine of 1 atom or more, and particularly preferably polytetrafluoroethylene.

The binder may be used up to about 420 ° C as long as it contains nitrogen and/or fluorine of 1 atom or more; the sheet of the present invention may be used up to about 500 ° C as long as the binder is polytetrafluoroethylene.

Hereinafter, specific embodiments will be described below.

The porous carbon used in the present invention can be produced, for example, in the following manner. First, wet or dry mixing in a solution or powder state A fluidity material containing an organic resin and an oxide (molding particles) are used to prepare a mixture. Next, the mixture is carbonized at a temperature of, for example, 500 ° C or higher in a non-oxidizing environment or a reduced pressure environment. Finally, the mold particles are removed by a washing treatment, whereby porous carbon can be produced. The porous carbon produced in such a manner has a large number of pores (middle pores and micropores). The arrangement of the pores is not regular, but is a structure that is randomly arranged (the mesopores are irregularly arranged).

Here, the pore diameter, the pore distribution of the porous carbon, and the thickness of the carbonaceous wall can be adjusted by changing the diameter of the mold particles or the type of the organic resin. Therefore, by appropriately selecting the diameter of the mold particles and the type of the organic resin, porous carbon having a different pore diameter or specific surface area can be easily produced.

Specifically, as the organic resin, a polyimine containing at least one nitrogen or fluorine atom in a unit structure can be preferably used. The polyimine is obtained by polycondensation of an acid component and a diamine component. However, in this case, it is necessary to contain one or more nitrogen atoms or fluorine atoms in either or both of the acid component and the diamine component.

Specifically, a polylysine film can be obtained by forming a film of polyglycine which is a precursor of polyimine and heating and removing the solvent. Next, the obtained polyaminic acid film is thermally imidated at 200 ° C or higher to produce a polyimide.

As the aforementioned diamine, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(trifluoromethyl)-linked can be exemplified. Aniline [2,2'-Bis(trifluoromethyl)-benzidine], 4,4'-diamino octafluorobiphenyl or 3,3'-difluoro-4,4'-diaminodiphenylmethane, 3,3'-difluoro-4,4'-diamine Diphenyl ether, 3,3'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3'-difluoro-4,4'-diaminodiphenyl Propane, 3,3'-difluoro-4,4'-diaminodiphenylhexafluoropropane, 3,3'-difluoro-4,4'-diaminodiphenyl ketone, 3,3 ',5,5'-tetrafluoro-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetrakis(trifluoromethyl)-4,4'-diaminodi Phenylmethane, 3,3',5,5'-tetrafluoro-4,4'-diaminodiphenylpropane, 3,3',5,5'-tetrakis(trifluoromethyl)-4, 4'-Diaminodiphenylpropane, 3,3',5,5'-tetrafluoro-4,4-diaminodiphenylhexafluoropropane, 1,3-diamino-5-(all Fluorodecenyloxy)benzene, 1,3-diamino-4-methyl-5-(perfluorodecenyloxy)benzene, 1,3-diamino-4-methoxy-5 -(perfluorodecenyloxy)benzene, 1,3-diamino-2,4,6-trifluoro-5-(perfluorodecenyloxy)benzene, 1,3-diamino- 4-chloro-5-(perfluorodecenyloxy)benzene, 1,3-diamino-4-bromo-5-(perfluorodecenyloxy)benzene, 1,2-diamino- 4-(perfluorodecenyloxy)benzene, 1,2-di 4-methyl-5-(perfluorodecenyloxy)benzene, 1,2-diamino-4-methoxy-5-(perfluorodecenyloxy)benzene, 1,2 -diamino-3,4,6-trifluoro-5-(perfluorodecenyloxy)benzene, 1,2-diamino-4-chloro-5-(perfluorodecenyloxy) Benzene, 1,2-diamino-4-bromo-5-(perfluorodecenyloxy)benzene, 1,4-diamino-3-(perfluorodecenyloxy)benzene, 1, 4-Diamino-2-methyl-5-(perfluorodecenyloxy)benzene, 1,4-diamino-2-methoxy-5-(perfluorodecenyloxy)benzene , 1,4-diamino-2,3,6-trifluoro-5-(perfluorodecenyloxy)benzene, 1,4-diamino-2-chloro-5-(perfluorodecene Benzyloxy)benzene, 1,4-diamino-2-bromo-5-(perfluorodecenyloxy)benzene, 1,3-diamino-5-(perfluorohexenyloxy) Benzene, 1,3-diamino-4-methyl-5-(perfluorohexenyloxy)benzene, 1,3-diamino-4-methoxy-5-(perfluorohexenyl) Oxyl) Benzene, 1,3-diamino-2,4,6-trifluoro-5-(perfluorohexenyloxy)benzene, 1,3-diamino-4-chloro-5-(perfluorohexyl) Alkenyloxy)benzene, 1,3-diamino-4-bromo-5-(perfluorohexenyloxy)benzene, 1,2-diamino-4-(perfluorohexenyloxy) Benzene, 1,2-diamino-4-methyl-5-(perfluorohexenyloxy)benzene, 1,2-diamino-4-methoxy-5-(perfluorohexene) Benzyl)benzene, 1,2-diamino-3,4,6-trifluoro-5-(perfluorohexenyloxy)benzene, 1,2-diamino-4-chloro-5- (Perfluorohexenyloxy)benzene, 1,2-diamino-4-bromo-5-(perfluorohexenyloxy)benzene, 1,4-diamino-3-(perfluorohexyl) Alkenyloxy)benzene, 1,4-diamino-2-methyl-5-(perfluorohexenyloxy)benzene, 1,4-diamino-2-methoxy-5-( Perfluorohexenyloxy)benzene, 1,4-diamino-2,3,6-trifluoro-5-(perfluorohexenyloxy)benzene, 1,4-diamino-2- Chloro-5-(perfluorohexenyloxy)benzene, 1,4-diamino-2-bromo-5-(perfluorohexenyloxy)benzene or p-phenylenediamine containing no fluorine atom An aromatic diamine such as (PPD) or dioxydiphenylamine. Further, the diamine component may be used in combination of two or more kinds of the above aromatic diamines.

Moreover, as the fluid material, a resin which generates fluidity at a temperature of 200 ° C or lower or a polymer resin of a varnish type is preferably used. When a fluid which generates fluidity at a temperature of 200 ° C or lower or a varnish-like polymer resin is used as the fluid material, the above-described porous carbon can be produced more smoothly.

However, the fluid material is not limited to a resin that generates fluidity at a temperature of 200 ° C or lower, and does not generate fluidity at a temperature of 200 ° C or lower, as long as it is a polymer material soluble in water or an organic solvent. It can be used in the present invention. As such a material, PVA (polyvinyl alcohol), PET (polyethylene terephthalate) resin, quinone imine can be exemplified. Resin, phenolic resin, and the like.

Further, as the fluid material, it is preferable to use a carbon yield of 40% or more and 85% or less. If the carbon yield of the fluid material is too small or too large (specifically, if the carbon yield of the fluid material is less than 40% or exceeds 85%), there is a formation that cannot maintain the three-dimensional mesh structure. In the case of a carbon powder, if a fluid material having a carbon yield of 40% or more and 85% or less is used, after removing the mold particles, it is possible to surely obtain a three-dimensional network in which a place where the mold particles originally exist is a continuous hole. Porous carbon in the ocular structure. Further, if the particle diameters are substantially the same as the mold particles, since continuous pores having the same size can be formed, porous carbon having a sponge shape and a cage shape can be produced.

Further, if the carbon yield of the fluid material is in the above range, since the micropores are very developed, the specific surface area will become large. However, even if the carbon yield of the fluid material is in the above range, the micropores are not developed without using the mold particles.

On the other hand, as the acid component, 4,4-hexafluoroisopropylidene dicarboxylic anhydride (6FDA) containing a fluorine atom, and 3,4,3',4'-biphenyl tetra containing no fluorine atom can be exemplified. Carboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), and the like.

Further, examples of the organic solvent used as the solvent of the polyimide precursor are N-methyl-2-pyrrolidone and dimethylformamide.

As a method of ruthenium imidization, it can also be based on a well-known method [refer to, for example, the Polymer Society, "New Polymer Experiments", Co-published, March 28, 1996, Volume 3, Polymer Synthesis, Reaction (2) 158 As shown in the page, any method of heating or chemical hydrazine imidation, the present invention is not affected by the method of imidization.

Further, as the resin other than the polyimide, petroleum-based tar pitch, acrylic resin, or the like can be used.

On the other hand, as the raw material of the above-mentioned oxide, a metal organic acid which changes to a state of magnesium oxide during thermal decomposition by heat treatment in addition to an alkaline earth metal oxide (magnesium oxide, calcium oxide, or the like) may be used ( Magnesium citrate, magnesium oxalate, calcium citrate, calcium oxalate, etc.), chloride, nitrate, sulfate.

Further, as the cleaning liquid for removing the oxide, a usual inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, citric acid, acetic acid or formic acid is used, and a dilute acid of 2 mol/l or less is preferably used. Further, hot water of 80 ° C or higher can also be used.

Further, it is preferred that the carbonization of the mixture be carried out at a temperature of from 500 ° C to 1500 ° C in a non-oxidizing atmosphere or a reduced pressure atmosphere. The reason is that since the resin having a high carbon yield is a polymer, when the temperature is less than 500 ° C, the carbonization is insufficient and the pores are not sufficiently developed. On the other hand, when the temperature is 1500 ° C or higher, the shrinkage is large and the oxide is large. Since it is sintered and coarsened, the size of the pores becomes small and the specific surface area becomes small. The non-oxidizing environment refers to an argon atmosphere or a nitrogen atmosphere, and the reduced pressure environment refers to an environment of 133 Pa (1 torr) or less.

Further, the bulk density of the porous carbon is preferably 0.07 g/cc or more and 1.0 g/cc or less. If the bulk density is less than 0.07g/cc, it will be difficult to ensure the specific surface area, and the shape of the carbon wall will not be maintained. On the other hand, when the bulk density exceeds 1.0 g/cc or less, it is difficult to form a three-dimensional network structure, and the formation of pores may be insufficient.

Further, the porous carbon produced in the above manner is mixed with a binder, and then dried, and further, a porous carbon sheet can be produced by pressing. At this time, as the binder, polytetrafluoroethylene, polyimide, butadiene elastomer, acrylic elastomer, or the like can be used, and among them, polytetrafluoroethylene is particularly preferable.

[Examples] (Example 1)

As shown in Fig. 1(a), magnesium oxide powder (MgO, average particle diameter: 5 nm) 2 as a mold particle was mixed at a weight ratio of 3:2, and an organic resin (polyvinyl alcohol) 1 as a carbon precursor was mixed. . Next, as shown in FIG. 1(b), the mixture is thermally decomposed at 900 ° C for 2 hours in an inert atmosphere to thermally decompose the polyvinyl alcohol, thereby obtaining a burned material having the carbonaceous wall 3. . Next, the obtained fired product was washed with a sulfuric acid solution added at a ratio of 1 mol/l to completely dissolve the MgO. Thereby, as shown in FIG. 1(c), an amorphous porous carbon powder 5 having a plurality of pores 4 can be obtained.

Further, the porous carbon powder has an average particle diameter of 50 μm (particle diameter of 2 to 70 μm). Further, as shown in Fig. 10, the porous carbon powder is irregularly arranged in the carbonaceous wall, and the adjacent mesopores are in communication with each other, and the carbonaceous wall is formed into a three-dimensional network structure.

Then, the porous carbon powder and polytetrafluoroethylene (PTFE-6J manufactured by DuPont) were mixed at a weight ratio of 8:2, and stirred at room temperature, and then dried at 120 ° C using a dryer. The mixture was dried for 5 hours to obtain a mixture of porous carbon powder and Teflon (registered trademark). Finally, the above mixture was rolled by using a roll press (roll gap: 500 μm) to prepare a sheet having a specific surface area of 1200 m ² /g and a thickness of 500 μm.

Hereinafter, a sheet produced in such a manner is referred to as a sheet A1.

Here, when an external force is applied to the sheet A1 in the bending direction, it is bent as shown in FIG. 11, and when the external force is applied, it returns to the original state. For this reason, it was confirmed that the sheet A1 was flexible.

(Example 2)

A sheet was produced in the same manner as in Example 1 except that polytetramethylene was used instead of polytetrafluoroethylene as the above binder. Further, the specific surface area and thickness are the same as in the above-described first embodiment.

Hereinafter, a sheet produced in such a manner is referred to as a sheet A2.

Further, the sheet A2 was confirmed to have flexibility similarly to the sheet A1 described above.

(Comparative example)

In place of the above porous carbon, a commercially available activated carbon (manufactured by Wako Pure Chemical Industries, Ltd. (Product No. 037-02115)) is used as the carbon powder. A sheet was produced in the same manner as in Example 2 except for the powder. Further, the specific surface area and thickness are the same as in the above-described first embodiment.

Hereinafter, such a sheet is referred to as a sheet Z.

(Experiment 1)

As described above, since the sheets A1, A2, and Z were subjected to thermogravimetric analysis in an air atmosphere, the results are shown in Fig. 2 . Further, for reference, in the case where only the porous carbon used in Examples 1 and 2 was also measured, the results were also collectively shown.

As can be seen from Fig. 2, the sheet Z has a weight loss from the start of heating, and a significant weight loss occurs when it reaches about 200 °C or higher. In contrast, if the sheets A1 and A2 do not reach about 420 ° C or higher, no weight reduction will occur. In particular, the sheet A1 did not cause weight loss until it reached about 500 ° C, and it was found that heat resistance was superior to the case of only porous carbon.

(Experiment 2)

Alternately exposing the sheets A1, Z in a dry N ₂ environment and a wet N ₂ environment, and after exposing to a dry N ₂ environment to produce a weight reduction, it is possible to revert to the exposure time in a wet N ₂ environment for a long time. The original state (state before the start of the experiment) was investigated using the apparatus shown in Fig. 3, and the results are shown in Figs. 4 and 5.

Further, Fig. 4 is a graph showing the experimental results of the sheet A1, and Fig. 5 is a graph showing the experimental results of the sheet Z. Moreover, the apparatus of FIG. 3 is the apparatus used by this experiment, and it is set as the following structures. The sealing body 12 and 12 are sealed at both ends of the cylindrical body 11, and the sealing body 12 of one of the sealing bodies 12 and 12 penetrates the N ₂ gas introduction pipe 13 and the sealing body 12 of the other end penetrates the N _{2 .} Gas discharge pipe 16. A weight measuring table 14 on which a sheet is placed and which can continuously measure the weight of the sheet is disposed inside the cylindrical body 1. On the other hand, a heater 15 for heating the sheet is disposed outside the cylindrical body 11. Further, the dry N ₂ environment is at a temperature of 25 ° C and a humidity of about 1% or less, and the wet N ₂ environment is at a temperature of 25 ° C and a humidity of about 85%.

As can be seen from Fig. 5, the sheet Z cannot be returned to the original state after the introduction of the wet type N ₂ even after about 9 hours. As can be seen from Fig. 4, it can be confirmed that the sheet A1 is After the wet N _{2 is} introduced, it returns to its original state in a very short time. In order to investigate such experimental results, the following experiment 3 was carried out.

(Experiment 3)

The same amount of water droplets were dropped on the sheet A1 and the sheet Z, and the state of the water droplets dropped immediately after, and the state of the water droplets after 10 seconds from the dropping were examined, and the results are shown in FIGS. 6 to 9. In addition, FIG. 6 is a photograph showing a state in which water droplets of water droplets are dropped on the sheet A1, and FIG. 7 is a photograph showing a state of water droplets after 10 seconds from the dropping of the water droplets on the sheet A1; A photograph of the state of the water droplets immediately after the sheet Z; FIG. 9 is a photograph showing a state of water droplets after 10 seconds from the dropping of the water droplets on the sheet Z. Also, in Figures 6 to 9, 21 It is a thin sheet and 22 is a water drop.

As can be seen from FIG. 8 and FIG. 9, it can be confirmed that the state of the water droplets after the droplet Z has dropped the water droplets for a short time and the water droplets have elapsed for 10 seconds has not changed greatly, and the water has not penetrated into the sheet. In contrast, as can be seen from FIG. 6 and FIG. 7, it can be confirmed that the sheet A1 is soaked into the sheet immediately after dropping the water droplets; after 10 seconds from the dropping of the water droplets, most of the water is saturated to the sheet. . From this, it can be seen that the wettability of the sheet A1 is remarkably improved as compared with the sheet Z.

In this manner, since the wettability of the sheet A1 is excellent, as shown in the above experiment 2, after the wet type N _{2 is} introduced, it returns to the original state in a short time. On the other hand, since the wettability of the sheet Z is inferior, as described in the above experiment 2, it is considered that it is not possible to return to the original state after taking the wet N ₂ for a long time. In the case of the sheet A2, it is considered that the sheet A1 is also based on the same reason. Therefore, the wet type N ₂ is introduced and returned to the original state in a short time.

(Experiment 4)

Since the pore distributions of the sheets A1 and Z were investigated, the results are shown in Fig. 12. In the experiment, nitrogen was used as an adsorption gas, and the pore distribution was analyzed by a BJH method based on a nitrogen adsorption isotherm measured at a temperature of 77K.

As can be seen from Fig. 12, it is found that the sheet A1 has a pore diameter distribution in which a pore diameter of about 5 nm is set as a peak, and a mesopores exist. In contrast, it was found that the sheet Z had a flat pore diameter distribution without a peak, and no mesopores were present.

[Industry Utilization]

The present invention can be used as a gas filter, a gas diffusion layer, a spacer, a catalyst carrier, an electrode, or the like.

Claims (5)

A porous carbon flake characterized by comprising a porous carbon powder and a binder, wherein the porous carbon powder has a mesoporous hole, and adjacent mesopores communicate with each other. The porous carbon sheet according to claim 1, wherein the ratio of the binder to the porous carbon powder is 5% by weight or more and 50% by weight or less. The porous carbon flakes of claim 1 or 2, wherein the film thickness is from 250 μm to 1000 μm. The porous carbon sheet according to any one of claims 1 to 3, wherein the binder contains a binder of nitrogen and/or fluorine of 1 atom or more. The porous carbon sheet according to claim 4, wherein the binder containing nitrogen and/or fluorine of 1 atom or more is polytetrafluoroethylene.