Porous carbon, electrode material, catalyst carrier, capacitor, fuel cell, secondary battery, and method for producing porous carbon

Abstract

Disclosed is a powder porous carbon which has a specific surface area of 1,400 m2 / g to 2,800 m2 / g, a micropore volume of 0.2 cm3 / g to 1.4 cm3 / g, and a mesopore volume of 0.2 cm3 / g to 1.4 cm3 / g, wherein the total gas amount of hydrogen (H2) derived from terminal hydrogen of carbon, water (H2O) derived from an oxygen-containing functional group, carbon monoxide (CO), and carbon dioxide (CO2) detected from the porous carbon by temperature-programmed desorption gas analysis is 0.01-2.0 mmol / g.

Description

Porous carbon, electrode material, catalyst support, capacitor, fuel cell, secondary battery, and method for manufacturing porous carbon

[0001] This disclosure relates to porous carbon, electrodes using the same, and a method for producing porous carbon.

[0002] To realize a sustainable society, development is underway on next-generation high-performance energy devices that support the widespread adoption of electric vehicles such as fuel cell vehicles and electric vehicles, as well as the construction of hydrogen supply chains. In the development of electrochemical devices that handle advanced energy storage and power generation functions, it is no exaggeration to say that electrode material production process technology and electrode interface control technology hold the key to improving device performance.

[0003] Activated carbon, a type of classical porous carbon, has been widely used as an electrode in electrochemical devices due to its large specific surface area and economic viability (see, for example, Non-Patent Document 1).

[0004] On the other hand, in recent years, porous carbons have been developed in which the microstructure, such as pore size and specific surface area, which was difficult to control with activated carbon, is highly controlled. For example, alumina (Al ２ O ３ A method for producing porous carbon called graphene mesosponge is known, in which nanoparticles of alkaline earth metal oxides (MgO, CaO) or other alkaline earth metal oxides are used as templates. After forming several layers of graphene on these template nanoparticles by chemical vapor deposition (CVD) using methane gas, the template nanoparticles are removed by acid etching (see, for example, Patent Documents 1 and 2).

[0005] Furthermore, a method for producing porous carbon is known in which an organic substance such as polyvinyl alcohol (PVA) is mixed with metal oxide (MgO) nanoparticles and fired, and then the metal oxide (MgO) nanoparticles of the template are removed by etching (see, for example, Patent Document 3).

[0006] I. Mochida, S. - I. Lee, S. Mitani, S. - H. Yoon and Y. Korai, Tanso 2003 [No. 210] 250-257 [in Japanese]

[0007] Japanese Patent Publication No. 6460448, Japanese Patent Publication No. 7407393, Japanese Patent Publication No. 6677863

[0008] The porous carbon according to the present disclosure is a powdery porous carbon having each property of a specific surface area of 1400 m ２ / g to 2800 m ２ / g, a micropore volume of 0.2 cm ３ / g to 1.4 cm ３ / g, and a mesopore volume of 0.2 cm ３ / g to 1.4 cm ３ / g, and the total amount of gas of hydrogen (H ２ ) derived from terminal hydrogen of carbon, water (H ２ O) derived from oxygen-containing functional groups, carbon monoxide (CO), and carbon dioxide (CO ２ ) detected by temperature-programmed desorption gas analysis from the porous carbon is 0.01 to 2.0 mmol / g.

[0009] The method for producing porous carbon according to the present disclosure includes a pre-firing step of firing zinc organic acid or a mixture of an organic acid and a zinc precursor at 1000°C or lower in an inert gas atmosphere, and removing hydrogen, water, carbon monoxide, and carbon dioxide as gases during the heating process, while forming micropores and mesopores on the surface of the fired body of the remaining carbon by zinc oxide serving as a template, and then reducing and evaporating and removing the zinc oxide of the template to obtain a fired body of carbon having micropores and mesopores, and a main firing step of firing the fired body of carbon obtained by pre-firing at 1000°C or higher in an inert gas atmosphere to remove terminal hydrogen of carbon to obtain porous carbon.

[0010] This is a schematic cross-sectional view illustrating the cross-sectional structure of macropores, mesopores, and micropores on the surface of porous carbon according to Embodiment 1. This is a schematic flowchart of the method for manufacturing porous carbon according to Embodiment 1 of this disclosure. This figure shows in-situ XRD measurement data of the zinc citrate calcination process of Example 1. This figure shows XRD measurement data of zinc citrate of Example 1 at 300°C and 400°C. This figure shows TEM images of the 450°C decomposition product (a) and 900°C calcined product (b) of zinc citrate of Example 1. This is Table 1 summarizing the manufacturing conditions and evaluation results of Example 1 and Experimental Examples 1 to 9. This figure shows the TG-DTA results of Example 1. This figure shows the TG-DTA results of Experimental Example 1. This figure shows the TG-DTA results of Experimental Example 3. This figure shows the TG-DTA results of Experimental Example 5.

[0011] For example, when activated carbon is used as an electrode in an electric double-layer capacitor (EDLC), there is a problem that under high voltage operation, oxygen-containing surface functional groups and crystallographic defects on the activated carbon surface induce and accelerate the electrolysis of the electrode and electrolyte. Because activated carbon has a large amount of functional groups on its surface, a lot of by-products are generated under high voltage. However, because there are few mesopores (pore size 2 nm to 50 nm) that can trap these impurities, the cycle characteristics of the EDLC deteriorate under high voltage. Furthermore, even if oxygen-containing functional groups and terminal hydrogen present on the activated carbon surface are removed by high-temperature heat treatment (above 1000°C), the blockage of the micropores (pore size 2 nm or less) of the activated carbon causes a large structural change and shrinkage of the material, resulting in a decrease in the specific surface area. Thus, in activated carbon, there is a trade-off problem where it is not possible to achieve both functional group removal and specific surface area maintenance simultaneously.

[0012] Alumina (Al ２ O ３Conventional porous carbon, manufactured by CVD and etching using nanoparticles of alkaline earth metal oxides (MgO, CaO) as a template, uses nanoparticles with a diameter of at least 10 nm. This resulted in a problem of a small number of micropores (pore size of 2 nm or less). Furthermore, the metal oxide nanoparticles in the template had to be washed and removed with strong acids such as hydrofluoric acid, sulfuric acid, and hydrochloric acid. Therefore, in addition to firing equipment, washing and drying equipment were required for the production of porous carbon, and the large amount of acid waste liquid generated led to increased manufacturing costs and environmental burden. Moreover, because carbon has a high affinity for sulfur, sulfur tends to remain as an impurity in the carbon after sulfuric acid washing. In other words, conventional porous carbon faced the challenge of achieving both a high specific surface area, high pore volume, and a low amount of functional groups.

[0013] Therefore, the present disclosure aims to provide porous carbon that achieves both a high specific surface area and pore volume, and a low amount of functional groups.

[0014] The porous carbon according to the first embodiment has a specific surface area of ​​1400 m². ２ / g ~ 2800m ２ / g, micropore volume 0.2 cm ３ / g ~ 1.4cm ３ / g, mesopore volume 0.2 cm ３ / g ~ 1.4cm ３ A powdery porous carbon having the following properties, wherein hydrogen (H) derived from the terminal hydrogen of the carbon detected by temperature-controlled desorption gas analysis from the porous carbon. ２ ) and water (H) derived from oxygen-containing functional groups ２ O), carbon monoxide (CO), and carbon dioxide (CO) ２ The total amount of gas is 0.01 to 2.0 mmol / g.

[0015] The electrode material according to the second embodiment uses porous carbon according to the first embodiment described above.

[0016] The catalyst support according to the third embodiment uses porous carbon according to the first embodiment described above.

[0017] The capacitor according to the fourth embodiment uses the electrode material according to the second embodiment described above.

[0018] The fuel cell according to the fifth embodiment uses the electrode material according to the second embodiment described above.

[0019] The secondary battery according to the sixth embodiment uses the electrode material according to the second embodiment described above.

[0020] The capacitor according to the seventh embodiment uses the catalyst support according to the third embodiment described above.

[0021] The fuel cell according to the eighth embodiment uses the catalyst carrier according to the third embodiment described above.

[0022] The secondary battery according to the ninth embodiment uses the catalyst carrier according to the third embodiment described above.

[0023] A method for producing porous carbon according to the tenth embodiment includes a pre-calcination step in which zinc organic acid, or a mixture of organic acid and zinc precursor, is calcined at 1000°C or below in an inert gas atmosphere, and during the heating process, hydrogen, water, carbon monoxide, and carbon dioxide are removed as gases, while micropores and mesopores are formed on the surface of the remaining calcined carbon body by zinc oxide, which serves as a template, and then the zinc oxide template is reduced and evaporated to obtain a calcined carbon body having micropores and mesopores; and a main calcination step in which the calcined carbon body obtained by pre-calcination is calcined at 1000°C or above in an inert gas atmosphere to remove terminal hydrogen from the carbon and obtain porous carbon.

[0024] The method for producing porous carbon according to the above disclosure includes a pre-sintering step of producing a carbon sintered body by sintering an organic acid that serves as a carbon source and a material containing zinc or a zinc precursor that serves as a mold source at 1000°C or below, and a main sintering step of reducing terminal hydrogen and crystallographic defects of the carbon by sintering the carbon sintered body at 1000°C or above. The method for producing porous carbon is characterized in that, by changing at least two of the conditions such as the type of organic acid that serves as a carbon source, the ratio of the organic acid that serves as a carbon source to the zinc or zinc precursor that serves as a mold source, and the size of the mold, the amount of oxygen-containing functional groups such as hydroxyl groups, carboxyl groups, and ketone groups, and carbon terminal hydrogen present on the carbon surface is reduced while stably maintaining the high specific surface area and pore volume of the porous carbon.

[0025] With the above configuration, it is possible to reduce the amount of oxygen-containing functional groups and terminal hydrogen while suppressing large changes in the pore structure. The "pore structure" refers to a structure that has a large number of mesopores, as shown in the schematic diagram in Figure 1, and in which micropores are formed in the carbon wall that constitutes the outer casing of these mesopores, at positions surrounding the mesopores. Furthermore, the pore structure has a continuous pore structure in which the above mesopores are continuous. In addition, since the nanoparticles of the mold can be removed by firing alone without etching, etching equipment and drying equipment are not required, and the generation of large amounts of waste liquid, which has a high environmental impact, can be avoided, so the manufacturing cost of porous carbon can be greatly reduced.

[0026] (Embodiment 1) <Porous Carbon> Figure 1 is a schematic cross-sectional view illustrating the cross-sectional structure of macropores, mesopores, and micropores on the surface of porous carbon according to Embodiment 1.

[0027] The porous carbon according to Embodiment 1 is in powder form and has a specific surface area of ​​1400 m². ２ / g ~ 2800m ２ / g, micropore volume 0.2 cm ３ / g ~ 1.4cm ３ / g, mesopore volume 0.2 cm ３ / g ~ 1.4cm ３It possesses the characteristics of each of the / g. In addition, hydrogen (H) derived from the terminal hydrogen of carbon detected by temperature-controlled desorption gas analysis from porous carbon. ２ ) and water (H) derived from oxygen-containing functional groups ２ O), carbon monoxide (CO), and carbon dioxide (CO) ２ The total amount of gas is 0.01 to 2.0 mmol / g.

[0028] The porous carbon according to Embodiment 1 is effective as an electrode material and catalyst support for power generation and energy storage devices. Specifically, the porous carbon according to Embodiment 1 eliminates the trade-off between specific surface area and functional group content in activated carbon, which is commonly used as an electrode material for EDLCs, and can achieve both a high specific surface area and pore volume and a low functional group content. Furthermore, it eliminates the trade-off between specific surface area and oxidation resistance in conventional carbon materials, including Ketjenblack, which is commonly used as a support for electrode catalysts for fuel cells, and can achieve both a high specific surface area and high oxidation resistance.

[0029] (Specific surface area of ​​porous carbon) The BET specific surface area of ​​porous carbon according to this embodiment 1 is not particularly limited, but is 1200 m². ２ It is 1400m or more / g, preferably 1400m ２ It is 1 / g or more. The BET specific surface area of ​​porous carbon is 1200 m². ２ If the amount is greater than / g, a large capacity can be obtained when used as an electrode material for EDLC because the area of ​​the formed electrical double layer becomes larger. From the viewpoint of electrical double layer formation, the larger the BET specific surface area of ​​porous carbon, the better, but considering the balance with pore volume and functional group content, it is substantially 3000 m. ２ It is less than or equal to / g, preferably 2800m ２ It is less than / g.

[0030] The specific surface area of ​​porous carbon is, for example, N, based on JIS Z 8830:2013. ２ It is determined by gas adsorption measurement. Specifically, N ２ By performing BET plot analysis on the desorption side of the gas adsorption / desorption isotherm, the amount of N required to form a monolayer can be determined. ２ Calculate the gas volume (= specific surface area).

[0031] (Pore volume of porous carbon) In this specification, the definition of pore size follows that of the International Union of Pure and Applied Chemistry (IUPAC), with pores of 2 nm or less being called micropores, pores of 2 nm to 50 nm being called mesopores, and pores of 50 nm or more being called macropores.

[0032] The total pore volume of the porous carbon according to this first embodiment is, for example, 0.2 to 4.0 cm³. ３ The amount is / g, preferably 0.4 to 3.8 cm. ３ It is / g. The total pore volume is 0.2 cm³. ３ / g or more, especially 0.4cm ３ A high specific surface area can be obtained if the amount is greater than or equal to 1 / g. On the other hand, if the total pore volume is 4.0 cm³ ３ Less than / g, especially 3.8cm ３ If the value is less than / g, sufficient mechanical strength for use as an electrode can be ensured. Furthermore, the volume occupied by the micropores should be 0.1 m from the viewpoint of electrical double layer formation. ３ The amount is 0.2 m or more, preferably 0.2 m ３ It is 1.5 cm or more. On the other hand, in terms of maintaining mechanical strength, ３ It is less than or equal to / g, and preferably 1.4cm ３ It is less than / g. Furthermore, the volume occupied by the mesopores is 0.1 m, from the viewpoint of capturing by-products generated by the reaction of oxygen-containing functional groups and terminal hydrogens on the carbon surface with the electrolyte. ３ The amount is 0.2 m or more, preferably 0.2 m ３ It is 1.5 cm² or more. On the other hand, in order to obtain a high specific surface area, the volume occupied by the mesopores should be 1.5 cm². ３ It is less than or equal to / g, and preferably 1.4cm ３ It is less than / g.

[0033] The total pore volume of porous carbon is, for example, N, based on JIS Z 8830:2013. ２Gas adsorption measurements were performed, and the amount of adsorption at a relative pressure (P / P0) of 0.96 could be determined. The volumes of micropores and mesopores were determined from DFT analysis. Specifically, the adsorption kernel of the QSDFT method was used. However, since this kernel only has data up to ~33.2424 nm (below 33.2424 nm), the mesopore volume was calculated by subtracting the volume of micropores (~2 nm) from the volume up to 33.2424 nm.

[0034] (Amount of functional groups in porous carbon) The porous carbon according to this embodiment 1 was heated under reduced pressure at 100°C for 1 hour, then heated from 100°C to 1400°C at a rate of 20°C / min, and held at 1400°C for 30 minutes. The amount of H calculated from the temperature-programmed desorption-mass spectrometry (TPD-MS) was calculated from the temperature-programmed desorption-mass spectrometry (TPD-MS). ２ H ２ O, CO, CO ２ This is a porous carbon in which the total amount of released H is 0.01 to 2.0 mmol / g or less. For example, the amount of H per gram of porous carbon is calculated from TPD-MS measurement when the sample is heated under the above conditions. ２ H ２ O, CO, CO ２ If the total amount of gas released exceeds 2.0 mmol / g, the side reactions between the oxygen-containing functional groups and terminal hydrogen on the carbon surface and the electrolyte cannot be suppressed during high-voltage operation of the EDLC, and sufficient cycle characteristics cannot be obtained. ２ H ２ O, CO, CO ２ While there are no particular restrictions on the lower limit of hydrogen emission in EDLC from the viewpoint of obtaining sufficient cycle characteristics, in order to substantially reduce gas emission to less than 0.01 mmol / g, it is necessary to calcine at a high temperature of 2000°C or higher. However, at temperatures above 2000°C, problems such as a decrease in specific surface area due to further desorption of hydrogen at the carbon terminus, as well as increased process time and energy costs, become unavoidable, so it is preferable to have a specific surface area of ​​0.01 mmol / g or higher. Therefore, from the viewpoint of satisfying both high specific surface area and high durability, the amount of hydrogen per gram of porous carbon is ２ H ２ O, CO, CO２ The total amount of gas emitted is 2.0 mmol / g or less, and the BET specific surface area of ​​the porous carbon is 1400 m². ２ It is preferable that the amount is 1 / g or more.

[0035] The amount of oxygen-containing functional groups and terminal hydrogen contained in porous carbon samples can be estimated from TPD-MS measurements. For example, H ２ By measuring the release rate, the amount of hydrogen released at the carbon terminus can be estimated. ２ By measuring the amount of O and CO released, the total amount of functional groups such as hydroxyl groups derived from the phenol structure, carbonyl groups derived from the quinone structure, ethers, and acid anhydrides can be obtained. ２ By measuring the amount released, the total amount of functional groups such as carboxyl groups, lactones, and acid anhydrides can be obtained. Then, the H calculated by TPD-MS measurement is obtained. ２ H ２ O, CO, CO ２ The sum of each release amount is related to the total amount of terminal hydrogen and oxygen-containing groups contained in the porous carbon. Note that the quantitative determination of terminal hydrogen and oxygen-containing groups contained in porous carbon can also be performed by methods other than TPD-MS measurement (neutralization titration, TG-MS measurement, etc.). For example, in TG-MS measurement, results almost equivalent to those of TPD-MS can be obtained by holding at 100°C for 1 hour under reduced pressure, then increasing the temperature from 100°C to 1400°C at a rate of 20°C / min, and holding at 1400°C for 60 minutes.

[0036] In porous carbon, terminal hydrogen and oxygen-containing functional groups are more abundant at the edge plane (EP) of graphene than at the basal plane (BP). Therefore, H ２ H ２ O, CO, CO ２The greater the amount of released hydrogen, the greater the amount of terminal hydrogen and oxygen-containing functional groups, and the greater the amount of edge surfaces (EP) present in the porous carbon microstructure. Since edge surfaces (EP) are more reactive and more easily oxidized than basal surfaces (BP), when this material is used as an electrode in EDLC, it is thought that the less EP present, the better the cycle characteristics and the higher the capacity retention rate under high voltage operation.

[0037] (Oxidation Resistance of Porous Carbon) Oxidation of porous carbon significantly reduces the durability of devices, therefore, the oxidation resistance of carbon is an important indicator. In fuel cells, which generate electricity directly by chemically reacting hydrogen and oxygen, the carbon, which is the catalyst support, is susceptible to oxidative degradation when a high voltage is applied in an environment where oxygen and water are present. The oxidation resistance of the porous carbon according to this embodiment 1 is not particularly limited, but for example, if the residual mass at 600°C is 98.0% or more as a result of thermogravimetric differential thermal analysis (hereinafter referred to as TG-DTA), the oxidation resistance of the carbon is considered to be sufficiently high (it can be said that the oxidation or combustion reaction of carbon has not progressed), and therefore it is considered that it can exhibit sufficient durability in the actual use of devices such as fuel cells.

[0038] <Electrodes and Catalyst Supports Containing Porous Carbon> The electrode according to Embodiment 1 contains the porous carbon described above. The porous carbon according to Embodiment 1 has a large specific surface area, an appropriate micropore volume and mesopore volume, and a small amount of terminal hydrogen and oxygen-containing functional groups. Therefore, the porous carbon according to Embodiment 1 is suitable for a wide range of applications, such as electrodes or catalyst supports in energy storage devices such as EDLCs and LiB (lithium-ion secondary batteries), and power generation devices such as fuel cells and solar cells.

[0039] When the porous carbon according to Embodiment 1 is used, for example, as an electrode material for an EDLC high-voltage cell, it has an appropriate specific surface area, corrosion resistance due to its low functional group content, and pore volume, so it can exhibit high capacity and capacity retention. Furthermore, when the porous carbon according to Embodiment 1 is used, for example, as a platinum catalyst support for a fuel cell, it has an appropriate specific surface area, oxidation resistance, pore size distribution, and pore volume, so it can be expected to exhibit excellent oxygen reduction stress over a long period of time.

[0040] <Method for Manufacturing Porous Carbon> Figure 2 is a schematic flowchart of the method for manufacturing porous carbon according to Embodiment 1 of this disclosure.

[0041] A method for producing porous carbon according to this first embodiment will be described (Figure 2).

[0042] The method for producing porous carbon according to Embodiment 1 includes the following steps: (1) a pre-sintering step and (2) a main sintering step.

[0043] (1) Pre-calcination process (pore formation and zinc removal process): The organic acid zinc, or a mixture of organic acid and zinc precursor, is calcined at 1000°C or below under an inert gas atmosphere to remove hydrogen, water, carbon monoxide, and carbon dioxide as gases, while forming micropores and mesopores in the remaining carbon, and the zinc is evaporated to obtain a calcined carbon body.

[0044] (2) Main firing process (terminal hydrogen removal process): The pre-fired carbon sintered body is fired at 1000°C or higher in an inert gas atmosphere to remove terminal hydrogen from the carbon. Porous carbon is obtained by performing the above steps (1) and (2).

[0045] The above steps (1) and (2) may be performed separately, but in order to improve productivity by omitting the cooling time in step (1) and the heating time in step (2), steps (1) and (2) may be performed consecutively.

[0046] Each step is described in detail below.

[0047] (1) Pre-calcination process (carbonization, pore formation, and zinc evaporation removal process): The pre-calcination process involves calcining zinc organic acid, or a mixture of organic acid and zinc precursor, at a temperature of 1000°C or lower to perform carbonization, pore formation, and zinc removal. Carbonization and pore formation involve removing hydrogen, water, carbon monoxide, and carbon dioxide as gases from the zinc organic acid, or the mixture of organic acid and zinc precursor, during the heating process, while forming micropores and mesopores on the surface of the remaining carbon using zinc oxide as a template. Zinc removal involves reducing and evaporating the zinc oxide template. This pre-calcination process yields a calcined carbon body.

[0048] Firing in an atmospheric environment causes carbon in the raw material to combine with oxygen in the atmosphere, resulting in a combustion reaction that produces carbon dioxide. As a result, carbon is lost, so it is preferable to carry out the pre-firing process in an inert gas atmosphere. There are no particular restrictions on the type of inert gas, but from an economic standpoint, a nitrogen gas or argon gas atmosphere is preferred, and nitrogen gas is even more preferred. The inert gas atmosphere may be maintained by replacing the firing atmosphere with a gas flow rate of 0.1 to 10.0 liters / minute.

[0049] Furthermore, the firing process may be carried out by raising the temperature from a predetermined temperature at a rate of approximately 3 to 20°C / minute to reach the predetermined temperature. The target temperature range in the pre-firing process cannot be generalized as it depends on the firing method, type of firing furnace, processing time (holding time), and amount of raw material processed, but from the viewpoint of sufficiently removing oxygen-containing functional groups of carbon and reduced zinc, a temperature of 910 to 1000°C, which exceeds the boiling point of zinc (907°C), is preferred. Similarly, the processing time (holding time) cannot be generalized as it depends on the firing method, type of firing furnace, and amount of raw material processed, but a temperature of 0.5 to 20 hours is preferred, and a temperature of 1 to 15 hours is even more preferred. Furthermore, the pre-firing process may be carried out under a reduced pressure atmosphere. Both batch and continuous firing methods can be used. Firing furnaces such as core tube type, box furnace, rotary kiln furnace, and conveyor furnace can be used. In the batch process, raw materials are placed in a crucible and fired. The crucible material can be alumina, quartz, carbon, etc., and there are no particular restrictions.

[0050] (2) Main firing process (process for removing terminal hydrogen): The main firing process is a process to obtain porous carbon by firing the pre-fired carbon sintered body at 1000°C or higher in an inert gas atmosphere to remove terminal hydrogen from the carbon. There are no particular restrictions on the type of inert gas, but from an economic standpoint, a nitrogen gas or argon gas atmosphere is preferred, and nitrogen gas is more preferred. The inert gas atmosphere may be maintained by replacing the firing atmosphere with a gas flow rate of 0.1 to 10.0 liters / min. Alternatively, the firing may be performed by raising the temperature from a predetermined temperature at a heating rate of about 3 to 20°C / min to reach the predetermined temperature. The range of temperatures that can be reached in the main firing process cannot be generalized as it depends on the firing method, the type of firing furnace, the processing time (holding time), and the amount of raw material processed, but from the viewpoint of sufficiently removing terminal hydrogen from the carbon, it is preferably 1700 to 2000°C, and more preferably 1800 to 1900°C. Similarly, the processing time (holding time) cannot be generalized as it depends on the firing method, type of firing furnace, and amount of raw material processed, but 0.5 to 20 hours is preferable, and more preferably 1 to 15 hours. Furthermore, firing may be carried out under a reduced pressure atmosphere. Both batch and continuous firing methods can be used. Firing furnaces such as core tube type, box furnace, rotary kiln, and conveyor furnace can be used, but for firing at temperatures above 1200°C, a stationary core tube type or box furnace is preferred. In the case of the batch method, the raw materials are placed in a crucible and fired, and carbon is preferred as the crucible material from the viewpoint of heat resistance.

[0051] <Raw Materials for Porous Carbon> The raw materials for porous carbon according to this embodiment 1 may be any organic acid zinc raw materials containing zinc atoms in their molecular structure. Preferably, one or more selected from the group consisting of zinc citrate, zinc hydrogen citrate, zinc oxalate, zinc fumarate, zinc succinate, zinc caffeate, zinc chlorogenicate, zinc ferulate, zinc quinate, zinc lactate, zinc malonate, zinc gluconate, zinc tartrate, zinc malate, zinc benzoate, zinc picolinate, zinc octolate, etc. Two or more organic acid zinc raw materials may be mixed and used. The above organic acid zinc raw materials may be hydrated or anhydrous.

[0052] The raw materials for porous carbon are not limited to the above-mentioned organic acid zinc raw materials, but may also be mixtures of organic acids and zinc precursors. Examples of organic acids include known organic acids such as citric acid, oxalic acid, fumaric acid, succinic acid, caffeic acid, chlorogenic acid, ferulic acid, quinic acid, lactic acid, malonic acid, gluconic acid, tartaric acid, malic acid, benzoic acid, picolinic acid, and octic acid. Examples of zinc precursors include known zinc precursors such as zinc hydroxide, zinc nitrate, zinc sulfate, zinc acetate, zinc chloride, zinc carbonate, and zinc oxide.

[0053] <Ratio of raw materials> Two or more types of zinc organic acids may be used in a mixture, but there are no particular restrictions on the ratio of zinc organic acids. On the other hand, from the viewpoint of complex formation between the organic acid and zinc, the ratio of the organic acid to the zinc precursor is preferably 0.8 to 2.2 in molar ratio to 1.0 organic acid, and more preferably 1.0 to 2.0 zinc precursor. The method of mixing the organic acid and zinc precursor can be either wet or dry, and there are no particular restrictions.

[0054] According to the method for producing porous carbon in Embodiment 1 of this disclosure, porous carbon is obtained by performing a pre-calcination step of zinc organic acid, or a mixture of organic acid and zinc precursor, and a main calcination step. This makes it possible to remove the mold without etching, and to obtain porous carbon with significantly low content of oxygen-containing functional groups and terminal hydrogen without causing significant structural changes and shrinkage of the porous carbon. This makes it possible to produce porous carbon that is environmentally friendly and economically efficient.

[0055] Porous carbon and a method for producing the same according to Embodiment 1 of this disclosure will be described based on the following examples. However, the embodiments of this disclosure are not limited to the following examples.

[0056] <Example 1> (1) Pre-calcination process (carbonization, pore formation and zinc evaporation removal process) 6.0 g of zinc citrate (white powder, manufactured by Sigma-Aldrich, Zn) raw material is placed in a quartz inner case. ３ (C ６ H ５ O ７ ) ２( ) was placed and set in the central part of the core tube of the Motoyama rotary kiln RK-0330. The core tube was heated and fired in a stationary state without rotation (without stirring the powder raw material). Under a nitrogen gas atmosphere, the temperature was raised from 25 °C at a rate of 3 °C / min to 950 °C, and held and fired at 950 °C for 6 hours to carry out carbonization with pore formation, reduction of zinc oxide, evaporation and removal, and a pre-fired product (0.15 g of black powder, yield 2.5%) was obtained.

[0057] (2) This firing process (terminal hydrogen removal process) Furthermore, 2.55 g of the pre-fired product was heated from 25 °C at a rate of 10 °C / min to 1800 °C under an argon atmosphere and held and fired at 1800 °C for 2 hours to remove the terminal hydrogen of the porous carbon, and this fired product (2.41 g of black powder, yield 94.5%) was obtained.

[0058] (3) Specific surface area S ＢＥＴ and measurement of micropore / mesopore volume The specific surface areas of the pre-fired product and this fired product were determined by N ２ gas adsorption measurement based on JIS Z 8830:2013. That is, using an automatic specific surface area / pore size distribution measuring device manufactured by Anton Paar, nitrogen gas was adsorbed on the sample at a relative pressure of 77 K, and the adsorption isotherm was measured. From the measured nitrogen gas adsorption isotherm, the BET specific surface area was determined using the BET method, and the pore size distribution was determined using the DFT method. The applicable range of the BET method was set as P / P0 = 0.1 to 0.3 where linearity was recognized. The above analysis was performed, and the following results were obtained. (Specific surface area S ＢＥＴ and measurement results of micropore / mesopore volume) S ＢＥＴ : 2632 m ２ / g Micropore volume: 0.52 cm ３ / g Mesopore volume: 1.31 cm ３ / g (Specific surface area S ＢＥＴ and measurement results of micropore / mesopore volume of this fired product) S ＢＥＴ : 1861 m ２ / g Micropore volume: 0.31 cm ３ / g Mesopore volume: 1.02 cm ３ / g

[0059] (4) Analysis of evolved gases by high-temperature TPD-MS Using an apparatus in which a mass spectrometer (Q-MS: M-401 manufactured by Canon Anelva) was directly connected to a furnace with a temperature controller (ULVAC-RIKO E25), the behavior and amount of evolved gas components from the sample were detected as functions of temperature during heating. By using a furnace with a specification of 1500 °C for the heating furnace, it is possible to evaluate gas components generated in a higher temperature region than in general TPD-MS. The measurement was carried out under the condition that He gas was flowing at a flow rate of 300 mL / min, held at 100 °C for 1 hour, then heated from 100 °C to 1400 °C at a rate of 20 °C / min, and held at 1400 °C for 30 minutes. As a result, the following results were obtained. (Results of analysis of evolved gases from the pre-sintered product by high-temperature TPD-MS) ◇ Hydrogen derived from terminal hydrogen H ２ (m / z: 2): 1.30 mmol / g ◇ Water, carbon monoxide, and carbon dioxide derived from oxygen-containing functional groups H ２ O (m / z: 18): 0.042 mmol / g CO (m / z: 28): 0.255 mmol / g CO ２ (m / z: 44): 0.0054 mmol / g ◇ Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gases: 1.6 mmol / g (Results of analysis of evolved gases from the sintered product by high-temperature TPD-MS) ◇ Hydrogen derived from terminal hydrogen H ２ (m / z: 2): 0.16 mmol / g ◇ Water, carbon monoxide, and carbon dioxide derived from oxygen-containing functional groups H ２ O (m / z: 18): 0.195 mmol / g CO (m / z: 28): 0.441 mmol / g CO ２ (m / z: 44): 0.0213 mmol / g ◇ Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gases: 0.8173 mmol / g

[0060] (5) In-situ XRD measurement To clarify the micro / mesopore formation mechanism of porous carbon, zinc citrate as a raw material was sealed in a glass capillary tube, and the behavior of zinc citrate during the heating process from 25 °C to 450 °C under a nitrogen gas atmosphere (100 kPa) was measured by XRD. The heating rate at that time was 10 °C / min, and after reaching the target temperatures (100 °C, 200 °C, 300 °C, 400 °C), the X-ray was irradiated twice for 30 seconds while holding for 60 seconds.

[0061] Figure 3 shows the XRD measurement results of zinc citrate from 25 to 400°C. As shown in Figure 3, diffraction peaks originating from the raw material zinc citrate were detected up to 200°C, but the diffraction peaks of zinc citrate disappeared at 300°C and 400°C.

[0062] Figure 4 shows the XRD measurement results at 300°C and 400°C. At 300°C, faint diffraction peaks corresponding to the plane indices (100), (002), (101), (102), and (110) of zinc oxide (ZnO), indicated by ● in the figure, were detected. At 400°C, these diffraction peaks were detected even more strongly and clearly. From thermal analysis results, it is known that zinc citrate decomposes at around 260°C, and considering these XRD measurement results together, it is thought that zinc citrate decomposes at temperatures above 260°C, forming zinc oxide nanoparticles that serve as templates for pore formation.

[0063] (6) Transmission Electron Microscope (TEM) Observation To obtain direct evidence of zinc oxide nanoparticles that would likely be formed during the thermal decomposition of zinc citrate at temperatures above 260°C, TEM observation of zinc citrate decomposition products was performed. Figure 5(a) is a TEM image of zinc citrate decomposition products at 450°C, and Figure 5(b) is a TEM image of products calcined at 900°C. As shown in Figure 5(a), at 450°C, countless zinc oxide nanocrystals of 4-5 nm size were present, while as shown in Figure 5(b), the pore size of the porous carbon after calcination at 900°C was 4.5 nm. In other words, the size of the zinc oxide nanocrystals in Figure 5(a) and the pore size in Figure 5(b) were approximately the same. This revealed that zinc oxide nanocrystals are formed as a template in the temperature range of 260-500°C during the decomposition of zinc citrate.

[0064] (7) Oxidation Resistance Test To evaluate the oxidation resistance of porous carbon, a TG / DTA7200 (manufactured by Hitachi High-Tech) was used to heat the porous carbon from 25°C to 1000°C at a heating rate of 20°C / min under an atmospheric environment, and then hold it at 1000°C for 30 minutes. The mass loss due to the combustion reaction of carbon and the heat balance were then analyzed. The TG-DTA of the porous carbon obtained in Example 1 was measured, and the residual mass at 600°C was 98.56% (Figure 7A), indicating that the porous carbon obtained under these conditions has high oxidation resistance.

[0065] Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm ３ / g, mesopore volume 0.2–1.4 cm ３ Hydrogen (H) detected by temperature-controlled desorption gas analysis / g ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ Since all conditions were met, including the total amount of gas being between 0.01 and 2.0 mmol / g, the overall evaluation was a passing grade.

[0066] <Experimental Example 1> As porous carbon, steam-activated activated carbon YP50F (manufactured by Kuraray) was used. The analysis of this sample was carried out in the same manner as in Example 1, and the following results were obtained. (Specific surface area S ＢＥＴ (and measurement results of micropore / mesopore volume) S ＢＥＴ : 1592m ２ Micropore volume: 0.49 cm³ / g ３ / g Mesopore volume: 0.18cm ３ / g (Results of gas analysis by high-temperature TPD-MS) ◇Hydrogen H derived from terminal hydrogen ２ (m / z:2): 39 mmol / g ◇ Water, carbon monoxide, carbon dioxide H derived from oxygen-containing functional groups ２ O (m / z: 18): 0.242 mmol / g CO (m / z: 28): 1.51 mmol / g CO ２(m / z: 44): 0.99 mg mmol / g ◇Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gas: 41.742 mg mmol / g The oxidation resistance test of steam-activated activated carbon YP50F (manufactured by Kuraray) showed that the remaining mass at 600°C was 86.36%, indicating low oxidation resistance (Figure 7B). From the exothermic peak of DTA, the mass reduction of carbon was due to the combustion reaction by oxidation (C + O ２ →CO ２ It is thought to originate from ).

[0067] Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm ３ The saturation level per gram was satisfactory, but the mesopore volume was 0.2–1.4 cm³. ３ / g and hydrogen (H) detected by temperature-controlled desorption gas analysis. ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ The total amount of gases, such as 0.01–2.0 mmol / g, was not satisfactory, resulting in an overall failing grade.

[0068] <Experimental Example 2> Steam-activated activated carbon YP50F (0.38 g, manufactured by Kuraray) placed in a cylindrical carbon crucible was set in a Thermonic firing furnace. The furnace was fired at 1800°C for 2 hours under an argon gas atmosphere to obtain a fired product (yield 0.32 g, yield 84.2%). The analysis of this sample was carried out in the same manner as in Example 1, and the following results were obtained. (Specific surface area S) ＢＥＴ (and measurement results of micropore / mesopore volume) S ＢＥＴ 780m ２ Micropore volume: 0.21 cm³ / g ３ / g Mesopore volume: 0.18cm ３ / g (Results of gas analysis by high-temperature TPD-MS) ◇Hydrogen H derived from terminal hydrogen ２ (m / z:2): 0.12 mmol / g ◇ Water, carbon monoxide, carbon dioxide H derived from oxygen-containing functional groups ２ O (m / z: 18): 0.06 mmol / g CO (m / z: 28): 0.19 mmol / g CO ２(m / z: 44): 0.32 mg mmol / g ◇Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gas: 0.69 mg mmol / g Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, mesopore volume 0.2–1.4 cm ３ The saturation level per gram was satisfactory, but the micropore volume was 0.2–1.4 cm². ３ / g and hydrogen (H) detected by temperature-controlled desorption gas analysis. ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ The overall evaluation was unsatisfactory because the total amount of gases, such as 0.01 to 2.0 mmol / g, was not met.

[0069] <Experimental Example 3> CNovel MH (manufactured by Toyo Tanso) was used as the porous carbon. The analysis of this sample was carried out in the same manner as in Example 1, and the following results were obtained. (Specific surface area S) ＢＥＴ (and measurement results of micropore / mesopore volume) S ＢＥＴ : 1504m ２ Micropore volume: 0.13 cm³ / g ３ / g Mesopore volume: 1.67cm ３ / g (Results of gas analysis by high-temperature TPD-MS) ◇Hydrogen H derived from terminal hydrogen ２ (m / z:2): 3.3 mmol / g ◇ Water, carbon monoxide, carbon dioxide H derived from oxygen-containing functional groups ２ O (m / z: 18): 0.48 mmol / g CO (m / z: 28): 3.443 mmol / g CO ２ (m / z: 44): 0.338 mg mmol / g ◇Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gas: 7.56 mg mmol / g The oxidation resistance test results for CNovel MH (manufactured by Toyo Tanso) showed that the remaining mass at 600°C was 70.78%, indicating low oxidation resistance (Figure 7C). From the exothermic peak of DTA, the mass reduction of carbon was due to the combustion reaction by oxidation (C + O ２ →CO ２ It is thought to originate from ).

[0070] Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm３ The saturation level per gram was satisfactory, but the mesopore volume was 0.2–1.4 cm³. ３ / g and hydrogen (H) detected by temperature-controlled desorption gas analysis. ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ The overall evaluation was unsatisfactory because the total amount of gases, such as 0.01 to 2.0 mmol / g, was not met.

[0071] <Experimental Example 4> The porous carbon (3.29 g, manufactured by Toyo Tanso) from Experimental Example 4, placed in a cylindrical carbon crucible, was set in a thermonic firing furnace. The furnace was fired at 1800°C for 2 hours under an argon atmosphere to obtain a fired product (yield 2.09 g, yield 63.6%). Analysis of this sample was performed in the same manner as in Example 1, and the following results were obtained. Because the specific surface area decreased significantly during this firing, gas analysis by high-temperature TPD-MS was not performed. (Specific surface area S ＢＥＴ (and measurement results of micropore / mesopore volume) S ＢＥＴ : 1285m ２ Micropore volume: 0.13 cm³ / g ３ / g Mesopore volume: 1.25cm ３ Based on the above, the porous carbon obtained under these conditions has a micropore volume of 0.2 to 1.4 cm². ３ / g and mesopore volume 0.2–1.4 cm ３ The / g ratio was satisfactory, but the specific surface area was between 1400 and 2800 m². ２ The overall evaluation was a failure because it did not satisfy the requirement of / g.

[0072] <Experimental Example 5> CNovel MJ(4) 030-00 (manufactured by Toyo Tanso) was used as the porous carbon. The analysis of this sample was carried out in the same manner as in Example 1, and the following results were obtained. (Specific surface area S) ＢＥＴ (and measurement results of micropore / mesopore volume) S ＢＥＴ : 636m ２ / g Micropore volume: 0.04 cm³ ３ Mesopore volume: 1.64 cm³ / g ３ / g (Results of gas analysis by high-temperature TPD-MS) ◇Hydrogen H derived from terminal hydrogen ２(m / z:2): 2.5 mmol / g ◇ Water, carbon monoxide, carbon dioxide H derived from oxygen-containing functional groups ２ O (m / z: 18): 0.557 mmol / g CO (m / z: 28): 1.53 mmol / g CO ２ (m / z: 44): 0.124 mmol / g ◇Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gas: 4.71 mmol / g The oxidation resistance test results for CNovel MJ(4)030-00 (manufactured by Toyo Tanso) showed that the remaining mass at 600°C was 67.43%, indicating low oxidation resistance (Figure 7D). From the exothermic peak of DTA, the mass reduction of carbon was due to the combustion reaction by oxidation (C + O ２ →CO ２ It is thought to originate from ).

[0073] Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm ３ / g, mesopore volume 0.2–1.4 cm ３ Hydrogen (H) detected by temperature-controlled desorption gas analysis / g ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ The overall evaluation was unsatisfactory because the total amount of gases, such as 0.01 to 2.0 mmol / g, was not met in all aspects.

[0074] <Experimental Example 6> The porous carbon (3.20 g, manufactured by Toyo Tanso) from Experimental Example 6, placed in a cylindrical carbon crucible, was set in a thermonic firing furnace. The furnace was fired at 1800°C for 2 hours under an argon atmosphere to obtain a fired product (yield 2.72 g, yield 84.9%). Analysis of this sample was performed in the same manner as in Example 1, and the following results were obtained. Gas analysis by high-temperature TPD-MS was not performed. (Specific surface area S) ＢＥＴ (and measurement results of micropore / mesopore volume) S ＢＥＴ : 632m ２ / g Micropore volume: 0 cm ３ Mesopore volume: 1.99 cm³ / g ３ Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm３ / g, mesopore volume 0.2–1.4 cm ３ Because it did not satisfy all the requirements of / g, the overall evaluation was a failure.

[0075] <Experimental Example 7> CNovel MJ(4) 010-00 (manufactured by Toyo Tanso) was used as the porous carbon. Gas analysis of this sample was performed by high-temperature TPD-MS, and the following results were obtained. Specific surface area S ＢＥＴ Micropore / mesopore volume measurements were not performed. (Results of generated gas analysis by high-temperature TPD-MS) ◇Hydrogen H derived from terminal hydrogen ２ (m / z:2): 2.55 mmol / g ◇ Water, carbon monoxide, carbon dioxide H derived from oxygen-containing functional groups ２ O (m / z: 18): 1.47 mmol / g CO (m / z: 28): 2.49 mmol / g CO ２ (m / z: 44): 1.0 mg mmol / g ◇Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gas: 7.51 mg mmol / g Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm ３ / g, mesopore volume 0.2–1.4 cm ３ Hydrogen (H) detected by temperature-controlled desorption gas analysis / g ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ The overall evaluation was unsatisfactory because the total amount of gases, such as 0.01 to 2.0 mmol / g, was not met in all aspects.

[0076] <Experimental Example 8> The porous carbon (0.14 g, manufactured by Toyo Tanso) from Experimental Example 8, placed in a cylindrical carbon crucible, was set in a thermonic firing furnace. The furnace was fired at 1800°C for 2 hours under an argon atmosphere to obtain a fired product (yield 0.13 g, yield 93.0%). Gas analysis of this sample was performed by high-temperature TPD-MS, and the following results were obtained: Specific surface area S ＢＥＴ Micropore / mesopore volume measurements were not performed. (Results of generated gas analysis by high-temperature TPD-MS) ◇Hydrogen H derived from terminal hydrogen ２(m / z:2): 2.18 mmol / g ◇ Water, carbon monoxide, carbon dioxide H derived from oxygen-containing functional groups ２ O (m / z: 18): 0 mmol / g CO (m / z: 28): 0 mmol / g CO ２ (m / z: 44): 0 mg mmol / g ◇Total amount of hydrogen, water, carbon monoxide, and carbon dioxide gas: 2.18 mg mmol / g Based on the above, the porous carbon obtained under these conditions has a specific surface area of ​​1400 to 2800 m². ２ / g, micropore volume 0.2–1.4 cm ３ / g, mesopore volume 0.2–1.4 cm ３ Hydrogen (H) detected by temperature-controlled desorption gas analysis / g ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ The overall evaluation was unsatisfactory because the total amount of gases, such as 0.01 to 2.0 mmol / g, was not met in all aspects.

[0077] Figure 6 is Table 1, which summarizes the manufacturing conditions and evaluation results for Example 1 and Experimental Examples 1 to 8.

[0078] <Considerations regarding structural maintenance in porous carbon related to this disclosure> Porous carbon obtained by pre-calcining and main calcination of zinc citrate has a specific surface area, micropore volume, mesopore volume, and hydrogen (H) detected by temperature-induced desorption gas analysis. ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO) ２ All requirements were met, such as the total amount of gas being within the desired range (Example 1). However, the specific surface area of ​​the activated carbon decreased significantly during the final firing (Experimental Example 3). In relation to this, we will consider below why the specific surface area can be maintained to some extent during the final firing of the zinc citrate pre-fired material.

[0079] In the case of activated carbon, 39 mM of hydrogen derived from terminal hydrogen was detected per gram by TPD-MS (Experimental Example 1). In contrast, in the case of zinc citrate, only an extremely small amount, 1.30 mM, was detected, which is 1 / 243rd of the amount detected in activated carbon (pre-calcined product). Furthermore, regarding oxygen-containing functional groups, the amount of gas detected (water (H)) was also small. ２O), carbon monoxide (CO), carbon dioxide (CO) ２ In general, zinc citrate contained 0.30 mmol / g, which was one-ninth less than activated carbon. From the above, it is thought that activated carbon, which generates a large amount of gas, underwent significant structural changes and a remarkable decrease in specific surface area during the calcination process due to the removal of a large amount of terminal hydrogen and oxygen-containing functional groups by thermal decomposition, resulting in the blockage of micropores and ring fusion.

[0080] On the other hand, the porous carbon relating to this disclosure is thought to have avoided significant structural changes and a decrease in specific surface area due to the low amount of terminal hydrogen and oxygen-containing functional groups in the raw materials and pre-calcined products, as a result of micropore blockage and ring fusion.

[0081] The method for producing porous carbon according to this disclosure includes a pre-calcination step of calcining an organic acid zinc, or a mixture of an organic acid and a zinc precursor, at a temperature of 1000°C or lower under an inert gas atmosphere to obtain a calcined carbon body having micropores and mesopores, and a main calcination step of calcining the calcined carbon body at a temperature of 1000°C or higher under an inert gas atmosphere to remove terminal hydrogen from the carbon and obtain porous carbon. As described above, by calcining at a temperature of 1000°C or higher, it is possible to produce and provide porous carbon in which the total amount of oxygen-containing functional groups and terminal hydrogen on the surface of the porous carbon and the microstructure (mesopore capacity, micropore capacity, specific surface area) are highly controlled. This material is expected to be a high-performance electrode material because it has a low amount of oxygen-containing functional groups and terminal hydrogen, has micropores / mesopores, and has a large specific surface area.

[0082] The porous carbon and method for producing the same according to this disclosure includes a pre-calcination step of calcining an organic acid zinc, or a mixture of an organic acid and a zinc precursor, at a temperature of 1000°C or lower under an inert gas atmosphere to obtain a calcined carbon body having micropores and mesopores, and a main calcination step of calcining the calcined carbon body at a temperature of 1000°C or higher under an inert gas atmosphere to remove terminal hydrogen from the carbon and obtain porous carbon. As described above, by calcining at a temperature of 1000°C or higher, it is possible to produce and provide porous carbon in which the total amount of oxygen-containing functional groups and terminal hydrogen on the surface of the porous carbon and the microstructure (mesopore capacity, micropore capacity, specific surface area) are highly controlled. Because this material has a low amount of oxygen-containing functional groups and terminal hydrogen, has an appropriate micropore / mesopore volume, and has a large specific surface area, it can be applied to a wide range of applications, such as power generation devices such as fuel cells and solar cells, and high-performance electrode materials for energy storage devices such as lithium-ion secondary batteries and electric double-layer capacitors.

Claims

1. Powdery porous carbon having each property of specific surface area of 1400 m ２ / g to 2800 m ２ / g, micropore volume of 0.2 cm ３ / g to 1.4 cm ３ / g, mesopore volume of 0.2 cm ３ / g to 1.4 cm ３ / g, wherein the total amount of gas of hydrogen (H ２ ) derived from terminal hydrogen of carbon, water (H ２ O) derived from oxygen-containing functional groups, carbon monoxide (CO), and carbon dioxide (CO ２ ) detected by temperature-programmed desorption gas analysis from the porous carbon is 0.01 to 2.0 mmol / g. Porous carbon.

2. An electrode material using the porous carbon described in claim 1.

3. A catalyst support using the porous carbon described in claim 1.

4. A capacitor using the electrode material described in claim 2.

5. A fuel cell using the electrode material described in claim 2.

6. A secondary battery using the electrode material described in claim 2.

7. A capacitor using the catalyst support according to claim 3.

8. A fuel cell using the catalyst carrier described in claim 3.

9. A secondary battery using the catalyst support described in claim 3.

10. A method for producing porous carbon, comprising: a pre-calcination step in which zinc organic acid, or a mixture of organic acid and zinc precursor, is calcined at a temperature of 1000°C or lower under an inert gas atmosphere, and during the heating process, hydrogen, water, carbon monoxide, and carbon dioxide are removed as gases, while micropores and mesopores are formed on the surface of the remaining carbon calcined body by zinc oxide, which serves as a template; and then the zinc oxide of the template is reduced and evaporated to obtain a carbon calcined body having micropores and mesopores; and a main calcination step in which the carbon calcined body obtained by the pre-calcination is calcined at a temperature of 1000°C or higher under an inert gas atmosphere to remove terminal hydrogen from the carbon and obtain porous carbon.

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