WO2003014018A1

WO2003014018A1 - Carbon material, gas occluding material comprising said carbon material and method for storing gas using said gas occluding material

Info

Publication number: WO2003014018A1
Application number: PCT/JP2002/007708
Authority: WO
Inventors: Yasunori Yokomichi; Hitoshi Nishino; Katsuhiro Sasaki; Ryoichi Nishida; Takeo Matsui
Original assignee: Osaka Gas Company Limited
Priority date: 2001-08-06
Filing date: 2002-07-29
Publication date: 2003-02-20

Abstract

A carbon material which has a real density of 2.1 to 3.1 g/cm3, has a H/C weight ratio of 0.013 or less as determined by elemental analysis, has a volume of ultra-micropores having a pore diameter not larger than 0.6 nm of 0.05 ml/g or more as measured by the ultra high vacuum nitrogen adsorption method at -196˚C, has two or more types of hydrogen adsorbing sites, exhibits d002 determined by the powder X-ray diffraction method (incident X-ray: CuKα) of 4.3 Å or more, and comprises a nanoscale carbon material having an amorphous structure which is composed of amorphous carbon particles, amorphous carbon fibers or a mixture thereof; a gas occluding material comprising said carbon material; and a method for storing a gas using said gas occluding material.

Description

Description Carbon material, gas storage material comprising the carbon material, and gas storage method using the gas storage material

The present invention relates to a carbon material, and more particularly to a carbon material having an amorphous structure, a gas storage material made of the carbon material, and a gas storage method using the gas storage material. Background art

Activated carbon is widely known as a carbon-based gas storage material. Activated carbon has many pores during the manufacturing process, which is due to the crystal structure of activated carbon being an amorphous structure. It is thought that gas molecules are adsorbed on such pores.The type of gas that can be absorbed depends mainly on the size of the pore diameter, and the amount of gas adsorbed depends on the surface area or pore volume of the pores. It is considered.

Conventionally, to improve the gas storage characteristics of activated carbon,? Activated carbon has been manufactured under activation conditions that can provide more pores on the tongue carbon surface.

However, halogen gas such as chlorine, fluorine, bromine, iodine, phosgene, etc., chain and formula hydrocarbons, halogenated hydrocarbons, alcohols, ethers, esters, ketones, aniline, carbon disulfide, etc. Even if activated carbon is the most suitable for storing organic gas, it is necessary to store liquid with very low critical temperature (e.g., 239.8T :) such as hydrogen by using liquid nitrogen temperature (e.g., 196 ° C). ) It was necessary to cool the activated carbon until the storage at room temperature was difficult.

Accordingly, an object of the present invention is to provide a carbon material which can store a gas having a very low critical temperature such as hydrogen even at room temperature. Disclosure of the invention

The present inventors have conducted intensive studies to produce a carbon material that can occlude a gas having a very low critical temperature such as hydrogen even at room temperature, and as a result, treated a certain raw material under specific conditions. By doing so, it is possible to obtain an amorphous nano-carbon having an amorphous structure, for example, a carbon material containing amorphous carbon particles, an amorphous carbon fiber, and the like. It has been found that it has the ability to occlude gases with low critical temperatures even at room temperature.

The present invention has been completed based on the above findings and further studied, and provides the following carbon material, gas storage material and gas storage method.

Item 1 True density is 2.1 to 3.1 gZ cm ³ ,

The hydrogen / carbon weight ratio by elemental analysis is 0.013 or less,

-The volume of the Ultramiku orifice with a diameter of 0.6 nm or less is 0.05 ml / g or more when measured by the ultrahigh vacuum nitrogen adsorption method at 196 ° C,

Has two or more types of hydrogen adsorption sites,

Determined by the diffractometry method in powder X-ray diffraction (incident X-ray: CuKo;) d. 0 ₂ is greater than 4.30 A,

A carbon material characterized by containing nanoscale carbon having an amorphous structure composed of amorphous carbon particles, amorphous carbon fibers or a mixture thereof.

Pi from 1540CHT ¹ obtained in claim 2 Raman spectroscopy has a peak centered at 1650CHT ¹

Item 1 characterized in that the integrated intensity ratio (IaZlb) of the integrated intensity (la) of the peak to the integrated intensity (lb) of the peak having a peak center at 1200 cm- ¹ to 1500 cm- ¹ is 1 or less. The carbon material according to 1.

Item 3. The carbon material according to Item 1 or 2, wherein the specific surface area is 1000 m ² / g or more. Item 4 In the nitrogen gas adsorption isotherm at liquid nitrogen temperature (-196 ° C), the relative pressure

(That is, the ratio of the nitrogen pressure to the nitrogen saturated vapor pressure (Po) at 196 ° C: PZPO) shows a hysteresis loop in which the ratio between the adsorption amount on the desorption side and the adsorption amount on the adsorption side is 1.1 or more in the range of 0.5 or more. Item 4. The carbon material according to any one of Items 1 to 3 above.

Item 5 A gas P and a storage material comprising the carbon material according to any one of Items 1 to 4 above.

Item 6 A hydrogen storage material comprising the carbon material according to any one of Items 1 to 4.

Item 7 Gas is stored using the gas P and storage material described in Item 5 above. Gas storage method.

Item 8 A hydrogen storage method characterized by storing hydrogen using the hydrogen storage material according to Item 6 above. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph showing the hydrogen storage characteristics of activated carbon (TPD 5 ° C./min temperature rise) in Test Example 2.

FIG. 2 is a graph showing hydrogen storage characteristics (TPD 3 ° C./min temperature rise) of activated carbon in Test Example 2.

FIG. 3 is a graph showing hydrogen storage characteristics (TPD 5 ° C./min temperature rise) of the amorphous carbon material of the present invention in Test Example 2.

FIG. 4 is a graph showing the hydrogen storage characteristics (TPD 3 ° C./min temperature rise) of the amorphous carbon material of the present invention in Test Example 2.

Figure 5 is a graph showing the results of ultrahigh vacuum nitrogen adsorption measurement (SWPA method) in Test Example 3.

The abbreviations in FIGS. 1 to 4 have the following meanings.

“TPD” = Temperature Programmed Desorption

"QMS intensity" = intensity of quadrupole mass spectrum "E + 0 0 J = Γχ 10 ° J (ie" X 1 ")

In FIG. 5, SWPA stands for Super Wide Pressure Adsorption.

The carbon material of the present invention

The carbon material of the present invention has a property of absorbing gas and is a carbon material containing a nanoscale carbon having an amorphous structure. The carbon material of the present invention typically contains amorphous carbon such as amorphous carbon particles and amorphous carbon fiber.

Conventionally, carbon materials having a tube structure such as carbon nanotubes It has been considered to be useful as a gas storage material because it stores gas in the space (hollow portion) surrounded by the tube wall made of such a material.

On the other hand, the present invention provides an excellent gas occlusion that can absorb gas even at room temperature because the nanoscale carbon has a specific amorphous structure regardless of whether it has a tube structure or not. It was completed after finding that it had the ability.

The carbon material of the present invention contains a nanoscale force element substantially consisting of an amorphous structure. In particular, it is preferable that the nanoscale carbon has only an amorphous structure.

Since the carbon material of the present invention has an amorphous structure, it has many pores that effectively work for hydrogen adsorption at room temperature, particularly pores smaller than 2 nm in diameter (that is, ultra-fine particles having a pore diameter of 0.6 nm or less). It has a large number of edges on the hexagonal mesh of carbon. Here, the edge of the carbon hexagonal plane means the end carbon atom of the carbon hexagonal plane. This carbon atom is chemically very active due to its unsaturated sp ² electron, and easily reacts with foreign elements such as oxygen to form surface functional groups. It is presumed that effective interaction for hydrogen adsorption at room temperature occurs between these unsaturated sp ² electrons and surface functional groups and hydrogen.

The amorphous carbon particles constituting the carbon material of the present invention are carbon particles consisting of only an amorphous structure having a particle diameter of about 5 nm to 500 nm, especially about 10 to 400 nm, and have a spherical or cubic shape. Shape, rectangular parallelepiped, disk, flake, film or similar shape. Among these shapes, granules represented by a sphere, a cubic shape, and a rectangular parallelepiped shape, in particular, a spherical shape are more preferable than a fibrous shape when a material is formed at a high density. In particular, a nanopole in which the shape of the constituent amorphous wall is spherical or closed shell can be exemplified. The average diameter of the nanopoles is of the order of 0.5 to 50 nm, in particular 5 to 30 nm.

Further, the amorphous carbon fiber is a carbon fiber having a diameter of 100 nm or less, particularly about 5 to 500 nm, particularly about 10 to 400 nm, and has only an amorphous structure. The ratio (L / D) of the length L of the fiber to the outer diameter D is 2 or more, preferably 5 or more, and more preferably 50 to 500. The particle diameter of the amorphous carbon particles and the diameter of the amorphous fiber are measured by measuring the size of an image observed by a scanning electron microscope or a transmission electron microscope.

The carbon material of the present invention may be composed of amorphous carbon particles, amorphous carbon fibers, or the like, or may be composed of a mixture thereof.

The carbon material of the present invention has various physical properties. Hereinafter, these physical properties will be described.

True density>

The carbon material of the present invention has a true density of 2.:! ~ 3.1 gZ cm ³ about, is particularly 2.4～2.7.01 ³ extent. Here, the true density is usually measured by the same procedure as the weight method used for measuring the amount of stored hydrogen, by measuring the buoyancy of helium exerted on the sample under a pressure of! The volume was determined from the measured buoyancy and calculated from the weight / volume.

The hydrogen / carbon weight ratio by elemental analysis is 0.013 or less, preferably 0.011 or less, more preferably 0.0063 or less, and particularly 0.005 to 0.011.

The carbon material of the present invention has an ultra-micro pore diameter of 0.6 nm or less as measured by an ultra-high vacuum nitrogen adsorption method at 1196 ° C (ultimate vacuum = 10 to ¹⁵ Pa; SWPA method). Is at least 0.05 ml / g, especially 0.05-0.1 ml / g, preferably 0.05-0.08 ml / g

(See Test Example 3 below).

As used herein, "Ultra-micro pores", ultra-high vacuum nitrogen adsorption method at the one 196 (ultimate vacuum = 10_ ⁵ Pa) as measured by, it will have the following pore diameters 0.6nm .

In the present specification, “ultramicropore volume” or “ultramicropore volume” refers to the ultrahigh vacuum nitrogen adsorption at 1196 ° C. per 1 g of the carbon material of the present invention. measured by law (ultimate vacuum = 10- ⁵ Pa), it refers to the total volume of the following ultra Miku port pore diameter 0.6 nm. Samples of amorphous carbon material of the present invention, after holding 0.99 ° C, 2 hours under a reduced pressure of 10 ^"3 Pa or less, - 196 ° C, and have use gravimetry the adsorption isotherm of nitrogen at 10- ⁵ Pa By analyzing the obtained adsorption isotherm of nitrogen under ultra-high vacuum, the pore volume of pertramic mixture was determined.

Here, the above-mentioned SWPA means super wide pressure adsorption. In general, high-resolution adsorption (HRA) cannot detect the pores of the Ultramic mouth. In contrast, SWPA, the apparatus in the pressure (about 1 0- ² P a) of the HRA measuring device © 1/1 0 0 0 pressure or lower pressure than, i.e., 1 0- ⁵ P a or By using a lower pressure, the measurement method is improved so that the measurement of the pores of the Ultramic mouth can be performed. Among the carbon materials of the present invention, in the nitrogen gas adsorption isotherm at liquid nitrogen temperature (-196 ° C), the relative pressure (that is, the nitrogen pressure (P), the nitrogen saturated vapor pressure (Po (PZPO) in the range of 0.5 or more shows a hysteresis loop in which the ratio between the adsorption amount on the desorption side and the adsorption amount on the adsorption side is 1.1 or more. This is advantageous because it has the property that it can be stably held. Further, the carbon material of the present invention has a pore volume of 0.2 ml or less for micropores having a pore diameter of 2 nm or less determined by a Dubinin analysis method using a gas adsorption amount of a gas at a boiling point under atmospheric pressure in a gas adsorption method. / g or more. In the present specification, the term "micropore" refers to a pore having a pore diameter of 2 nm or less obtained by the Dubinin analysis method using the gas adsorption amount at the boiling point of the gas at atmospheric pressure in the above gas adsorption method. .

Here, the Dubinin analysis method is a method of obtaining the pore volume of the pores of the Miku mouth from adsorption isotherms of various gases. Here, using the nitrogen adsorption isotherm at the liquid nitrogen temperature, the pore volume of the pores in the orifice of Miku was determined by Dubinin-Radushkevich plot. In this method, the nitrogen gas adsorption method uses liquid nitrogen temperature (1 196) and various relative pressures of nitrogen (ratio of nitrogen pressure (P) to nitrogen saturated vapor pressure (Po) at 1 196: P / Po). In this method, the amount of nitrogen adsorbed on the sample is measured, and the specific surface area, pore volume, and pore size distribution of the solid are determined from the amount of nitrogen molecules adsorbed.

The measurement of the amount of nitrogen adsorbed on the sample in the present invention is performed by a constant volume method that calculates the amount of nitrogen adsorbed from a change in the nitrogen pressure in a container of known volume filled with the sample. A pore distribution measuring device (ASAP2400, manufactured by Micromeritics Co., Ltd.) was used. Before the nitrogen adsorption measurement, 0.02 g of the sample was heated at 200 ° C while evacuating the sample container, and the process was continued until the degree of vacuum in the sample container reached lOmmTorr. In the carbon material of the present invention, the pore volume of the micropores having a pore diameter of 2 nm or less determined by the above analysis method may be 0.2 ml / g or more, preferably 0.25 ml / g or more, more preferably 0.3mlZg or more. The upper limit of the pore volume is not particularly limited, but is generally about 1.5 ml / g, particularly about 2.0 ral / g.

The carbon material of the present invention has two or more (particularly 2 to 4) types of hydrogen adsorption sites. This was demonstrated by the fact that at least two peaks were observed in thermal desorption (TPD) measurement using hydrogen gas (see Test Example 2 below).

Further, the carbon material of the present invention is characterized by having an amorphous structure instead of graphite. The amorphous structure in the present invention is an average distance d between carbon hexagonal mesh planes obtained by a diffractometry method in a powder X-ray diffraction method (incident X-ray: CuKQ!). . ₂ is 0.43 nm (4.3 A) or more. d. _{0 2,} particularly preferably 0.43~ 0.55nm (4.3-5.5A) about.

Further, the amorphous carbon material of the present invention has a diffraction angle (2 is 25.1 degrees or less, preferably 24.1 degrees or less) determined by the diffractometry method in powder X-ray diffraction (incident X-ray: CuKQ!). In particular, it is 23.5-24.5 degrees, and the half-width at 2Θ band is 3.2 degrees or more, preferably 7 degrees or more, particularly 5.0 to 8.0 degrees.

Further, the carbon material of the present invention, the integrated intensity of a peak having a peak centered at 1540cm- ^¹ ~ SOcnT ¹ obtained by Raman spectroscopy (la), a peak having a peak one click from central 1200cm one ¹ to 1500Cm- ¹ It is preferable that the integrated intensity ratio R (= Ia / lb) to the integrated intensity (lb) be 1 or less.

This integrated intensity ratio has the following significance. That is, of the Raman-active vibrations of the graphite structure, which peak center of the scan Bae spectrum is observed Raman shift 1540cm- ^¹ ~ 1650cm- ¹ in the range (especially 1580cm- around ^1), E _{2 g} vibratory And originates from the lattice vibration in the carbon hexagonal plane. On the other hand, in general, the range of 1200 cm- ¹ to 1500 cm- ¹ The center of the spectrum peak is also observed around (especially around 1360 cm- ¹ ). This vibration is an _Alg- type vibration, which is thought to be caused by the transition or loss of the local structure from hexagonal symmetry to lower symmetry, reflecting the disorder of the crystal structure. I have.

Accordance connexion, ranging from 1540CnT ¹ of 1650Cm_ ¹ (especially 1580Cm_ ¹ near) range 1200CHT ¹ peak (la) having a peak Ichiku center of 1500Arufaita ^{_ 1} (especially 1360cm one ¹ near) a peak having a peak center ( The integrated intensity ratio R (= Ia / lb) of lb) is an index that has a strong correlation with the crystal structure.

Generally, when R is small, the crystallite size (L _a ) parallel to the basal plane is small. This reflects that the influence of the crystal structure of the crystal local part becomes strong when R is small. This reflects that the smaller the R, the lower the crystallinity of the structure.

Also, as can be seen from the Raman spectrum of diamond-like carbon, a broad spectrum having a peak center near 1360 cm- ¹ is considered to have a diamond-like structure, that is, a property derived from sp ³ bonds. Thus, the broad scan Bae spectrum near 1360Cm- ^1, but be derived from that L _a is small it is thought to be the main, there are cases where both the properties of sp ³ bonds. Here, a case where both the properties of sp ³ bonds is a case where in the structure sp ² is the main binding, partially sp ³ bond occurs. It is considered that the part where the sp ³ bond has occurred has a dangling bond of a carbon bond, or an atom other than carbon is bonded to the carbon atom, and is considered to be chemically active. This is presumed to be effective for gas storage at room temperature.

In the carbon material of the present invention, the integrated intensity ratio R (= Ia / lb) is preferably 1 or less, particularly preferably 0.9 or less.

The carbon material of the present invention has a specific surface area measured by the BET method of 1000 m ² / g or more, particularly 1000 to 1500 m ² / g.

Average area of carbon hexagonal mesh>

Further, the carbon material of the present invention is characterized in that the average area of one carbon hexagonal mesh plane is 0.85 nm ² or less. The average area of the carbon hexagonal mesh plane is calculated by squaring the length of the crystallite image included in a range of 10 OA squares selected arbitrarily in the observation image of the transmission electron microscope and the area of the carbon hexagonal mesh plane. By defining and summing the area of the carbon hexagonal meshes included in the range of 10 OA square by the number of carbon hexagonal meshes, the area value of each carbon hexagonal mesh is averaged.

The carbon material of the present invention has the various physical properties described above and is useful as a gas storage material.

Method for producing carbon material of the present invention

The carbon material of the present invention can be obtained by subjecting a fixed power source and a specific catalyst to heat treatment under specific conditions.

Examples of the carbon source include a fluorine-containing polymer or fluorine-containing carbon, and among them, PTFE film, PTTE powder, Freon 116 (C ₂ F ₆ ) and the like are preferable. Furthermore, polyimide can be used as a source of carbon. Polyimide has a property that the carbon skeleton is easily retained when pyrolyzed and carbonized, and pores are easily formed in the process of removing the desorbed components due to the thermal decomposition. A particularly preferred example is a polyimide film sold by DuPont under the trade name "Kapton". As the catalyst, an iron fluoride or iron oxide can be exemplified, inter alia FeF ₂ or Fe ₂ 0 ₃ is preferred. Although the particle size of these catalysts is not particularly limited, it is generally preferable to use them in the form of powder having an average particle size of about 0.01 to 50 m, particularly about 0.01 to about 10 m.

The carbon source and the catalyst are placed in a reactor separately or in contact with each other. For example, when a carbon source in the form of a film is used, a method in which the above powdery catalyst is uniformly sprinkled on a film and put into a reaction furnace can be exemplified, and when a powdery carbon source is used, the powdery catalyst is used. For example, a method in which a carbon source and catalyst particles are previously dry-blended or wet-blended and uniformly mixed and then placed in a reaction furnace can be exemplified. Although various reactors can be used, a vacuum furnace using a quartz tube, an alumina tube or the like can be generally used.

The reaction conditions are typically such that the carbon source and the catalyst are placed in the furnace as described above, the furnace is set to an inert gas atmosphere, and the pressure in the furnace is set to lPa to 200 kPa, preferably 5 Pa to The carbon material of the present invention is manufactured by setting the furnace temperature to 150 kPa, setting the furnace temperature to 600 to 1500 ° C, preferably 800 to 1200, and heating the furnace for 0.5 hours or more, particularly 0.5 to 5 hours. can do.

In the present invention, the product obtained by the above method may contain an iron compound which is a residue derived from the above catalyst, but this iron compound does not significantly impair the gas storage properties of the carbon material of the present invention. Therefore, the product obtained by the above method may be used as it is.

Gas storage material and gas storage method comprising carbon material of the present invention

The carbon material of the present invention is excellent in gas storage capacity. Therefore, the present invention also provides a gas occluding material comprising the carbon material of the present invention.

The carbon material comprising the carbon material of the present invention can stably store various gases at room temperature. Examples of the gas that can be stored by the gas storage material of the present invention include hydrogen, methane, argon, nitrogen, neon, and the like. The gas occluding material of the present invention has an advantage that the gas can be stably occluded at room temperature, and therefore has extremely high industrial value. In particular, the gas occluding material of the present invention has an occluding ability even at room temperature. For example, at a hydrogen pressure of 10 MPa, at room temperature, 1% or more, particularly 3 to 5% by weight of hydrogen, Indicates the amount of occlusion.

Since the carbon material of the present invention has many structures capable of stably adsorbing various gases, it can occlude various gases stably, and in particular, a gas having a very low critical temperature such as hydrogen. However, it can be stably stored even at a temperature around room temperature (for example, 0 to 40). In particular, the carbon material of the present invention is useful as a hydrogen storage material.

Further, by filling the carbon material of the present invention into a high-pressure gas cylinder container, it becomes possible to store more gas than can be stored in a high-pressure gas cylinder container of the same volume, and it is possible to improve the gas storage amount per unit volume. Become like

Therefore, the present invention also provides a gas storage method, particularly a hydrogen storage method, using the carbon material of the present invention.

Various methods can be employed to occlude the gas using the gas occlusion material of the present invention. Generally, for example, at a temperature of about 0 to 40, a gas occlusion material made of the carbon material of the present invention is used. What is necessary is just to expose to the said gas atmosphere. Here, the pressure of the above gas atmosphere Is not less than 0.03 MPa, preferably from 0.2 MPa to 50 MPa, more preferably from 0.5 MPa to 20 MPa.

The gas storage method of the present invention has an advantage that a gas such as hydrogen, which has been difficult to occlude at room temperature with conventional activated carbon, can be occluded well even at room temperature. The gas storage method of the present invention is also advantageous in that gas can be taken in and out only by pressure change. That is, gas can be taken in and out in the same way as a conventional gas cylinder.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these Examples, and various modifications can be made without departing from the present invention.

In Examples and Comparative Examples, each physical property of the obtained carbon material was measured according to the method described above.

Example 1

0.2 g of FeF ₂ powder (particle diameter: 500 m or less) was uniformly sprinkled on 600 pieces of PTFE film having a size of 60 mX 10 mm X 10 mm, and then placed in a furnace. The furnace used was a quartz tube with an inner diameter of 50 mm, a length of 650 mm, and a wall thickness of 2.5 mm. After the inside of the furnace was replaced with nitrogen three times, the pressure was reduced to 5 Pa, and the inside of the furnace was heated at 900 ° C for 1 hour to obtain 0.7 g of a carbon material.

As a result of SEM observation, the carbonaceous material obtained was composed of amorphous carbon with a diameter of 20 to 500 nm. Table 1 shows the physical properties of the obtained carbon material containing amorphous carbon fibers as a main component.

Example 2

The particle size 10 X m or less of the PTFE powder 10g and the particle size lO U m following Fe ₂ 0 ₃ powder 1 g were mixed using a mill, the mixture was placed in an alumina container was placed in a furnace. The same quartz tube as in Example 1 was used for the furnace. After the inside of the furnace was replaced with argon three times, the pressure was reduced to 5 Pa, and the furnace was heated at 1200 ° C for 1 hour to obtain 2.1 g of a carbon material.

As a result of SEM observation, the carbonaceous material was composed of amorphous carbon particles having a diameter of 20 to 200 nm. Table 1 shows the physical properties of the obtained carbon material mainly composed of amorphous force-pong particles. Example 3

A 5 m piece of a 100 mX 10 mm X 10 mm polyimide film (manufactured by DuPont, trade name "Rockton Film") was sprinkled with 1 _§ of powder uniformly and placed in a furnace. The same quartz tube as in Example 1 was used for the furnace. After the inside of the furnace was replaced with He three times, the furnace pressure was set to 50 Pa, the temperature was raised to 900 ° C at a heating rate of l ° CZmin, and the furnace was heated at 900 ° C for 1 hour to produce a carbon material. 1.6 g were obtained.

As a result of SEM observation, the carbonaceous material was composed of amorphous carbon particles having a diameter of 100 to 200 nm. Table 1 shows the physical properties of the carbon material containing the obtained amorphous carbon particles as a main component.

The physical properties in Table 1 above were all measured by the method described in the section “Carbon material of the present invention”. Therefore, in Table 1, the “true density”, “specific surface area”, “hydrogen-Z carbon weight ratio”, “volume of ultramicropores having pore diameters of 0.55 nm or less”, “d ₀₀₂ "," Integrated intensity ratio (IaZlb) ", and" the presence or absence of a hysteresis loop "were measured as follows.

“True density” was measured by the gravimetric method using helium.

"Specific surface area" was measured by the BET method.

“Hydrogen to carbon weight ratio” was calculated from the results of elemental analysis and elemental analysis.

The “volume of ultramicropores having a pore diameter of 0.55 nm or less” was measured according to the ultrahigh vacuum nitrogen adsorption method at 196 ° C. described above.

“D. ₂ ” is determined by the diffractometry method in powder X-ray diffraction (incident X-ray: CuKQ!).

"Integrated intensity ratio (IaZlb)" is the integrated intensity of a peak having a peak centered at l ^ Ocm- ¹ from 1650Cm- ¹ obtained by Raman spectroscopy (la), having a peak center from 1200Cm- ¹ to 1500 cm ^_1 This is the ratio of the integrated intensity to the integrated intensity (lb) of the peak.

The presence or absence of a hysteresis loop is defined as the relative pressure (ie, nitrogen pressure (P), — nitrogen saturation vapor pressure (Po) at 196 ° C) in the nitrogen gas adsorption isotherm at liquid nitrogen temperature (1 196 ° C). The ratio was determined by examining the presence or absence of a hysteresis loop in which the ratio between the adsorption amount on the desorption side and the adsorption amount on the adsorption side was 1.1 or more in the range of 0.5 or more.

Test example 1

With respect to the carbon material of the present invention produced in the above examples;! To 3, the hydrogen storage capacity was evaluated by the volumetric method at 25 ° C and a hydrogen pressure of lOMPa.

For comparison, activated carbon (physical properties: pore volume of micropores with a pore diameter of 2 nm or less = 0.19 ml / g, doo ^ O ^ Onm. Average area of one hexagonal carbon screen = 0.93 nm ² : these physical properties The measurement method is the same as in Table 1), and the amount of hydrogen storage was similarly evaluated. Table 2 shows the results. The evaluation criteria in Table 2 are as follows:

〇: The hydrogen storage amount was 1% by weight or more based on the weight of the storage material even at room temperature.

X: No hydrogen absorption was observed at room temperature. Table 2

Table 2 shows that conventional activated carbon does not absorb hydrogen at room temperature, but that the carbon material of the present invention has excellent hydrogen storage ability even at room temperature.

Test Example 2 Evaluation of hydrogen storage characteristics of sample by thermal desorption method

The hydrogen storage characteristics of the amorphous carbon material of the present invention and the activated carbon (comparative) were evaluated using a thermal desorption apparatus.

As the amorphous carbon material of the present invention, the one produced in Example 1 was used. A commercial product (trade name “Maxsorb”, manufactured by Kansai Thermal Chemical Co., Ltd.) was used as the activated carbon.

(1) Thermal desorption measurement procedure

a Pre-processing

① sample was placed in a sample tube, and kept warm said 1 hour to 250 ^D C after the pressure was reduced to 10_ ³ Pa.

② Cool to room temperature and introduce 1 atm of hydrogen.

(3) While maintaining the hydrogen pressure at 1 atm, it was cooled to below 165 ° C and maintained for 1 hour.

④ cooled remained evacuated to 10 one ⁴ Pa, and maintained under reduced pressure for 1 hour.

b Measurement

(1) The temperature was raised from 1 165 ° C (start temperature) to 50 ° C (end temperature) at a rate of 3 ° CZ, and the amount of desorbed hydrogen was measured.

(2) After repeating the above pretreatment a, at a heating rate of 5 Z for 1 165 ° C (start Temperature) to 50 ° C (end temperature), and the amount of desorbed hydrogen was measured.

(2) Evaluation of hydrogen storage characteristics of each Sankare by thermal desorption method

Figures 1 to 4 show the hydrogen storage characteristics of each sample using thermal desorption (TPD). 1 and 2 show the hydrogen storage properties of activated carbon, and FIGS. 3 and 4 show the hydrogen storage properties of the amorphous carbon material of the present invention.

In all samples, the measurement was stopped when the peak was not detected in the temperature range higher than about 25 ° C for about 25 times (5 to 10 minutes in measurement time).

As shown in Fig. 1 and Fig. 2, activated carbon has a slower heating rate from 57 minutes to 3 ° CZ, and the release of hydrogen is slower, resulting in a lower peak and a broader peak. A single peak was observed at around -178 even under the temperature increasing conditions. Therefore, it is assumed that activated carbon has only one kind of adsorption site.

On the other hand, as shown in FIGS. 3 and 4, the amorphous carbon material of the present invention has two peaks in a low temperature region of −160 ° C. or lower regardless of the heating conditions, and the peak position and the shape of the peaks Showed remarkable changes depending on the heating conditions. When the heating rate was 3 Z minutes, a weak broad peak was observed at around -50 ° C. These observations indicate that the amorphous carbon material of the present invention has at least two types of adsorption sites, and each of the adsorption sites has a complicated behavior upon hydrogen adsorption. Test example 3

Samples of amorphous carbon material of the present invention prepared by the method described in Example 1, 10_ ³ Pa after holding the following under vacuum at 0.99 ° C, 2 hours, ultra-high vacuum nitrogen adsorption measurements at _196 ° C (SWPA Method), the graph shown in Fig. 5 was obtained.

Here, the above-mentioned SPA indicates super wide pressure adsorption. In general, high-resolution adsorption (HRA) cannot detect the pores of the Ultramic mouth. In contrast, SWPA is 1/1 0 0 0 pressure or lower pressure than that of the device the pressure of the HRA measuring apparatus (about 1 0- ² P a), i.e., 1 0- ⁵ P a or By using a lower pressure, the measurement method is improved so that the measurement of the pores of the Ultramic mouth can be performed. Analysis of this graph showed that the volume of ultramicropores of 0.55 nm or less was It was shown to be 0.06 ml / g.

In the graph of FIG. 5, Pobs on the horizontal axis indicates the measured nitrogen pressure, and Pvap indicates the nitrogen vapor pressure at the measurement temperature. INDUSTRIAL APPLICABILITY The carbon material of the present invention can stably occlude various gases, and in particular, stably occlude gases such as hydrogen having a very low critical temperature even at room temperature. Therefore, the industrial value is extremely high.

Claims

True density of 2.1~3.1 g / cm ^3,

The hydrogen / carbon weight ratio by elemental analysis is 0.013 or less,

-Ultra-micro vacuum nitrogen adsorption method at 196 ° C has a volume of pores of Ultramiku with a diameter of 0.6 nm or less of 0.05 ml / g or more and has two or more hydrogen adsorption sites. ,

In powder X-ray diffraction method (λ-irradiated X-ray: CuKa), d _Q 02 obtained by the diffractometer method is 4.30 A or more,

A carbon material comprising amorphous carbon particles, amorphous carbon fibers, or nanoscale carbon having an amorphous structure composed of a mixture thereof. The integrated intensity ratio to the integral intensity of a peak having a peak centered at ¹ (lb) ^- peak with a peak centered at 1650Cm_ ¹ from 1540Cm_ ¹ obtained by Raman spectroscopy - the integrated intensity of the click of (la), 1500 cm from 1200Cm- ¹ 2. The carbon material according to claim 1, wherein (Ia / Ib) is 1 or less. ^2. The carbon material according to claim 1, having a specific surface area of 1000 m ² / g or more. In the adsorption isotherm of nitrogen gas at liquid nitrogen temperature (1 196 ° C), the relative pressure (ie, the ratio of nitrogen pressure (P) to nitrogen saturated vapor pressure (Po) at _196: P / Po) is 0.5 or more 2. The carbon material according to claim 1, wherein the carbon material exhibits a hysteresis loop in which the ratio between the adsorption amount on the desorption side and the adsorption amount on the adsorption side is 1.1 or more. A gas P and storage material comprising the carbon material according to claim 1. A hydrogen storage material comprising the carbon material according to claim 1. A gas storage method using the gas storage material according to claim 5 to store gas. A hydrogen storage method comprising storing hydrogen using the hydrogen storage material according to claim 6.