JP2009091208A - Hydrogen storage material, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen storage material having high productivity regarding a hydrogen storage material mainly used, e.g., for the storage and transport of energy in a fuel tank for a hydrogen automobile, a chemical heat pump or the like and a method for producing the same. <P>SOLUTION: Disclosed is the hydrogen storage material with a micro porous structure on the surface, which is composed of a structure essentially constituted of a trifunctional type fundamental unit expressed by general formula RSiO<SB>1.5</SB>(R denotes a methyl group or a phenyl group) and a tetrafunctional type fundamental unit expressed by SiO<SB>2</SB>. A micro porous structure is formed on the surface, and the micro porous structure has each macro hole, each meso hole formed within the macro hole, and each micro hole formed at least on the surface of the meso hole and adsorbing hydrogen atoms. Regarding the micro hole, a siloxane bond (-O-Si-O-) is inserted into two Si atoms, it has a tetracyclosiloxane structure, and hydrogen molecules are incorporated into the tetracyclosiloxane structure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrogen storage material mainly used for storing and transporting energy such as a fuel tank for a hydrogen automobile and a chemical heat pump, and a method for producing the same.

Conventionally, as a hydrogen storage method, a high-pressure hydrogen cylinder, a liquefied hydrogen cylinder, a hydrogen storage alloy, a carbon material, an organic material, or the like, which is an existing technology, is currently used as a hydrogen storage medium. As a hydrogen storage alloy, LaNi ₅ which is an alloy of lanthanum and nickel has been energetically studied (see Non-Patent Document 1 below). In addition, research on nanostructured graphite and the like is underway for carbon-based materials (see Non-Patent Document 2 below). The most suitable example of utilization of hydrogen storage / transport technology is application to a hydrogen fuel tank in a fuel cell vehicle. In a moving medium such as a fuel cell vehicle, it is required to supply hydrogen stably and safely to a battery. However, a high-pressure cylinder has a risk of explosion and the like. There is a point that needs to be improved for practical use, such as a small amount of hydrogen storage per unit mass.

Yasuaki Osaku: “Hydrogen Energy Utilization Technology”, page 26, published by Agne Technology Center (2002). Zuttel, A. et al .: MRS BULLETIN, 27 (9) (2002), p.705.

However, there are the following problems even when using a hydrogen storage alloy with a commercial record at present.
1) It is expensive.
2) Since it is an alloy, its weight is large and the amount of occlusion per unit is small.
3) Degradation of the alloy due to repeated occlusion-release occurs, such as pulverization and structural changes.
4) When rare metals are included, it is necessary to secure resources for the future.

  Carbon-based materials, organic-based materials, etc. have no commercial results and are in the research and development stage. However, carbon-based materials require cooling with liquid nitrogen, and containers with high pressure resistance are also required.

  The present invention has been made in view of the above problems, and an object thereof is to provide a hydrogen storage material with good productivity.

According to one aspect of the present invention, a trifunctional basic unit represented by the general formula RSiO _1.5 (R represents a methyl group or a phenyl group), a tetrafunctional basic unit represented by SiO ₂ , and , A hydrogen storage material having a microporous structure on the surface is provided.

  The hydrogen storage material can form a hard film or a molded product having a dense three-dimensional structure. However, the liquid state of the present invention includes a high-viscosity substance state such as a paste or gel, and is preferably a paste having a viscosity adjusted to about 100 cps to 10000 cps.

  The porous structure preferably includes macropores, mesopores formed in the macropores, and micropores formed on at least the surface of the mesopores and adsorbing hydrogen molecules.

  The micropore has a tetracyclosiloxane structure represented by the chemical formula (3) in which a siloxane bond (—O—Si—O—) is inserted between the left and right Si atoms in the chemical formula (2). It is characterized in that hydrogen molecules are taken into the tetracyclosiloxane structure.

但し、化学式（１）及び（２）において、Rはメチル基またはフェニル基を表す。

However, in chemical formula (1) and (2), R represents a methyl group or a phenyl group.

  This tetracyclosiloxane structure has a diameter of about 0.4 nm, which corresponds to a micropore in the hydrogen storage material of the present invention, and it is considered that hydrogen molecules having a molecular diameter of about 0.28 nm are mainly adsorbed in this pore. . Further, since the occlusion of hydrogen in the present invention is mainly due to the adsorption of hydrogen molecules, the occlusion / release of hydrogen can be easily performed as compared with a method in which hydrogen atoms form a chemical bond.

The hydrogen storage material has the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ 0.1). a number in the range of n ≦ 0.6, x and y are x + 2y = 4 and a number in the range of 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25). It is preferable to contain metal or metal oxide-based fine particles in the precursor as the main agent.

  The proportion of the metal or metal oxide fine particles is preferably 0.5 to 20%, more preferably 1 to 10%. By containing the metal or metal oxide fine particles in the precursor containing the silicone resin as a main agent, the hydrogen storage capacity can be improved as compared with the case where the precursor is not contained. When the content is less than 0.5%, there is almost no effect to be contained. When the content is more than 20%, it is difficult to disperse the fine particles in the main agent, and a uniform mixture cannot be obtained.

The metal or metal oxide-based fine particles are preferably composed of one or more fine particles of Al, Ti, Si, Ag, alumina, titanium oxide, and SiO ₂ .

  The metal or metal oxide-based fine particles listed above can be uniformly dispersed and confused without agglomeration among the fine particles when mixed with the above-mentioned precursor containing silicone resin as a main component. It is.

  The metal or metal oxide fine particles preferably include ultrafine particles having an average particle diameter of about 1 nm to about 50 nm. Ultrafine particles having an average particle size of about 1 nm to about 50 nm and other fine particles having an average particle size of about 50 nm to about 1 mm are generally commercially available and can be used in the present invention. The hydrogen storage material is characterized by being vacuum-heated at least once at a temperature not higher than a temperature at which the hydrogen storage material is cured. The vacuum heat treatment may be performed at a temperature of 230 ° C. or lower and the silicone resin in a liquid state, but a temperature of 60 ° C. to 200 ° C., more preferably 60 to 160 ° C. is used. If it is 230 degreeC or more, the liquefied silicone resin may start thermosetting. If it is 60 ° C. or lower, the silicone resin may not be in a liquid state. The vacuum evacuation may be performed at a low vacuum with a degree of vacuum of about several thousand Pa as long as the pressure is reduced. It is believed that the vacuum heat treatment sufficiently advances the defoaming process of the raw material and increases the density of the microporous structure on the surface of the material when it is made into a hydrogen storage material. Thereby, hydrogen storage capacity can be improved compared with the case where there is no vacuum heat processing.

The hydrogen storage material is preferably a powder material having a particle size of about 0.05 mm to 5 mm, more preferably about 0.1 mm to 2 mm. The material after the thermosetting step is mechanically pulverized, and the material after the thermosetting step is a unit by mechanically pulverizing such as a mortar or a ball mill. The surface area per mass is increased, and the hydrogen storage capacity can be improved as compared with the case where no mechanical pulverization is performed. Moreover, it is preferable to classify and use the pulverized material according to the method of use. The particle size is preferably about 0.05 mm to 5 mm, more preferably about 0.1 mm to 2 mm. General formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0.6. And x, y is a number in the range of x + 2y = 4 and 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25). It is characterized by containing fine particles of metal or metal oxide.

According to another aspect of the present invention, the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0). .1 ≦ n ≦ 0.6, x and y are x + 2y = 4 and 0.2 ≦ x ≦ 1.5, z is an integer of z ≧ 25) A hydrogen comprising: a step of preparing a precursor containing a silicone resin as a main component; a step of adjusting to a liquid state at a temperature of 230 ° C. or lower; and a step of thermosetting at a temperature of 200 ° C. to 500 ° C. A method of manufacturing a storage material is provided.

The general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0.6) The number of ranges, x and y are x + 2y = 4 and the number is in the range of 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25). And metal or metal oxide fine particles. The metal or metal oxide fine particles are preferably composed of one or more fine particles of Al, Ti, Si, Ag, alumina, titanium oxide, and SiO ₂ .

  The metal or metal oxide fine particles preferably include ultrafine particles having an average particle diameter of about 1 nm to about 50 nm. It is preferable to include a step of performing a vacuum heat treatment at least once at a temperature equal to or lower than a temperature at which the precursor containing the silicone resin as a main component is cured. It is preferable to have the process of performing a mechanical grinding | pulverization process after the said thermosetting process.

  According to the present invention, according to the present invention, it is possible to provide a hydrogen storage material having a fine porous structure on the surface, heat resistance of 300 ° C. or more, and excellent water resistance.

  Accordingly, it is possible to provide a hydrogen storage material that can efficiently store hydrogen and can be safely handled under conditions that do not greatly deviate from normal temperature and normal pressure. Therefore, application to a hydrogen fuel tank for a fuel cell, which is a power source of a fuel cell vehicle, is enhanced, and its industrial benefit is extremely large.

  Hereinafter, a method for producing a hydrogen storage material and a method for measuring hydrogen storage characteristics according to an embodiment of the present invention will be described with reference to the drawings. The hydrogen storage material is “a material in which the material and structure are devised so that hydrogen can be easily stored”.

The hydrogen storage material according to the present invention is represented by the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group, Ph is phenyl, as exemplified by the chemical formula represented by (3)). M and n are numbers in the range of m + n = 1 and 0.1 ≦ n ≦ 0.6, and x and y are in the range of x + 2y = 4 and 0.2 ≦ x ≦ 1.5. And a step of adjusting a precursor containing a silicone resin as a main component represented by the formula (z, an integer of z ≧ 25) to a liquid state at a temperature of 230 ° C. or lower and a step of thermosetting at a temperature of 200 ° C. to 500 ° C. It is formed by.

Here, the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0. A silicone resin represented by a number in the range of 6, x, y is x + 2y = 4 and a number in the range of 0.2 ≦ x ≦ 1.5, z is an integer of z ≧ 25) is generally used as a paint. It is a substance obtained by stirring and degassing a substance called a silicone varnish used for color developing materials and the like at a temperature of around 100 ° C. for a long time, and is a substance that blocks the permeation of water and oxygen. Since this is usually a solid substance at room temperature, it is heated to a temperature of 230 ° C. or lower, adjusted to a liquid state, and then thermally cured at a temperature of 200 ° C. to 500 ° C. When the general formula RSiO _1.5 (R is a methyl group) Or a basic unit called a trifunctional type represented by a phenyl group and corresponding to x = 1, y = 1.5 in the above general formula) or SiO ₂ (corresponding to x = 0, y = 2 in the above general formula) It is possible to form a hard film or a molded product having a dense three-dimensional structure mainly composed of a basic unit called a tetrafunctional type represented by In general formula RSiO _1.5, for example, are exemplified by the formula (4).

(但し、ＩＩＩ、ＩＶの比率は、上記一般式のｘの値と、熱硬化させる工程の温度と時間が反映され、ｘが小さいほど、また熱硬化させる工程の温度が高く時間が長いほど、ＩＶ、ＩＩＩの順で比率が小さくなる。)

(However, the ratio of III and IV reflects the value of x in the above general formula and the temperature and time of the heat curing step. The smaller x, the higher the temperature of the heat curing step and the longer the time, (The ratio decreases in the order of IV and III.)

  However, the liquid state includes a high-viscosity material state such as a paste or gel, and is preferably a paste having a viscosity adjusted to about 100 cps to 10000 cps.

An example of the above general formula is represented by a structural formula. The chemical formula (3) (R is a methyl group or a phenyl group, II is a basic structure of bifunctional type (R ₂ SiO), III is a trifunctional type (RSiO _1.5 ) Basic structure, IV is tetrafunctional type (SiO ₂ ) basic structure). Here, the order and ratio of II, III, and IV can be appropriately determined in each case. The ratio of II, III, and IV in the chemical formula (3) reflects the value of x in the above general formula, and the smaller the x, the smaller the ratio in the order of IV, III, and II. The order of II, III, and IV is not particularly general.

  The inventors of the present invention provide that the film or molded product after the above-mentioned thermosetting has a fine porous structure on the surface, has a heat resistance of 300 ° C. or more, and is obtained as a hydrogen storage material excellent in water resistance. As a result, the present invention was reached.

  As an example, the fine porous structure 11 on the surface has a mesopore 17 of 2 to 50 nm in the macropore 15 of> 50 nm in the graphite carbon-based material as shown in FIG. <2 nm micropores 21 exist, and it is considered that hydrogen molecules are adsorbed in the micropores.

  However, although the structure of the micropore differs depending on the material such as amorphous or carbon nanotube in the graphite carbon-based material, the micropore in the hydrogen storage material of the present invention may be as shown in the chemical formula (3). A general polysiloxane structure is a structure represented by the above chemical formula (2), but the hydrogen storage material of the present invention has a siloxane bond between two Si atoms on the left and right sides as shown in the chemical formula (2). (—O—Si—O—) is inserted to form a structure containing many tetracyclosiloxane structures as shown in chemical formula (3). This tetracyclosiloxane structure has a diameter of about 0.4 nm, which corresponds to a micropore in the hydrogen storage material of the present invention, and it is considered that hydrogen molecules having a molecular diameter of about 0.28 nm are mainly adsorbed in this pore. . Further, since the occlusion of hydrogen in the present invention is mainly due to the adsorption of hydrogen molecules, the occlusion / release of hydrogen can be easily performed as compared with a method in which hydrogen atoms form a chemical bond.

  Among the above general formulas, m and n are numbers in the range of m + n = 1 and 0.1 ≦ n ≦ 0.6. Further, it is preferably a number in the range of m + n = 1 and 0.2 ≦ n ≦ 0.4. When n is 0.1 or less, or 0.6 or more, the heat resistance of the silicone resin is deteriorated and the fine porous structure on the surface is reduced, so that it is sufficient in the step of thermosetting at a temperature of 200 ° C. to 500 ° C. It may become impossible to obtain a material having characteristics. X and y are numbers that are in the range of x + 2y = 4 and 0.2 ≦ x ≦ 1.5. When x is 0.2 or less, the solid silicone resin may not be prepared in the liquid state necessary for the next thermosetting step in the step of adjusting to a liquid state at a temperature of 230 ° C. or less. Further, when x is 1.5 or more, in the step of thermosetting at a temperature of 200 ° C. to 500 ° C., the thermosetting becomes insufficient, the mechanical strength is lowered, and a material having sufficient characteristics cannot be obtained. There is a case. Z is an integer of z ≧ 25. When z is less than 25, in the step of thermosetting at a temperature of 200 ° C. to 500 ° C., the thermosetting becomes insufficient, the mechanical strength is lowered, and a material having sufficient characteristics may not be obtained. .

  Further, the temperature of the step of adjusting to a liquid state at a temperature of 230 ° C. or lower is 230 ° C. or lower, and usually a temperature at which a solid silicone resin becomes a liquid state at room temperature, but preferably 60 ° C. to 200 ° C. Preferably a temperature of 60-160 ° C is used. If it is 230 degreeC or more, the liquefied silicone resin may further start thermosetting. If it is 60 ° C. or lower, the silicone resin may not be in a liquid state. The temperature of the step of thermosetting at a temperature of 200 ° C. to 500 ° C. may be any temperature that cures in the range of 200 ° C. to 500 ° C., but a temperature of 300 ° C. to 450 ° C. is preferably used. If it is 200 ° C. or lower, curing may not proceed sufficiently, and if it is 500 ° C. or higher, the obtained material may be thermally decomposed to liberate single carbon.

Further, the hydrogen storage material has the above general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0. A number in the range of 1 ≦ n ≦ 0.6, x and y are x + 2y = 4 and a number in the range of 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25) A precursor containing a resin as a main component may contain metal or metal oxide fine particles.

  By containing the metal or metal oxide fine particles in the precursor containing the silicone resin as a main component, the hydrogen storage capacity can be improved as compared with the case where the precursor is not included. The content ratio is preferably 0.5 to 20%, more preferably 1 to 10%. When the content is less than 0.5%, there is almost no effect to be contained. When the content is more than 20%, it is difficult to disperse the fine particles in the main agent, and a uniform mixture cannot be obtained.

In the hydrogen storage material, the metal or metal oxide fine particles may be made of one or more fine particles of Al, Ti, Si, Ag, alumina, titanium oxide, and SiO ₂ . In this case, the metal or metal oxide fine particles include ultrafine particles having an average particle diameter of about 1 nm to about 50 nm. Ultrafine particles having an average particle size of about 1 nm to about 50 nm and other fine particles having an average particle size of about 50 nm to about 1 mm are generally commercially available and can be used.

  The hydrogen storage material is characterized in that the vacuum heat treatment is performed at least once at a temperature lower than a temperature at which the hydrogen storage material is cured. The vacuum heat treatment may be performed at a temperature of 230 ° C. or lower and the silicone resin is in a liquid state, but a temperature of 60 ° C. to 200 ° C., more preferably 60 to 160 ° C. is used. If it is 230 degreeC or more, the liquefied silicone resin may start thermosetting. If it is 60 ° C. or lower, the silicone resin may not be in a liquid state. The vacuum evacuation may be performed at a low vacuum with a degree of vacuum of about several thousand Pa as long as the pressure is reduced. It is believed that the vacuum heat treatment sufficiently advances the defoaming process of the raw material, and increases the density of the microporous structure on the surface of the material when the hydrogen storage material is formed. Thereby, hydrogen storage capability can be improved compared with the case where there is no vacuum heat processing.

  The hydrogen storage material may be mechanically pulverized after the thermosetting step. The material after the thermosetting process is mechanically pulverized using a mortar or ball mill, and the surface area per unit mass is increased. Compared to the case where no mechanical pulverization is performed, hydrogen storage is possible. The ability can be further improved.

  Moreover, it is preferable to classify and use the pulverized material according to the method of use. The particle size is preferably about 0.05 mm to 5 mm, more preferably about 0.1 mm to 2 mm.

Next, the manufacturing method of the hydrogen storage material by this Embodiment is demonstrated. The manufacturing method according to this embodiment has a general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1, and 0. A number in the range of 1 ≦ n ≦ 0.6, x and y are x + 2y = 4 and a number in the range of 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25) It has the process of adjusting the precursor which makes a resin the main ingredient into a liquid state at the temperature of 230 degrees C or less, and the process of thermosetting at the temperature of 200 to 500 degreeC. Here, the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0. 6 is a precursor having a silicone resin as a main component, wherein x and y are x + 2y = 4 and 0.2 ≦ x ≦ 1.5, z is an integer of z ≧ 25) A step of incorporating metal or metal oxide fine particles into the body may be added. At this time, the metal or metal oxide-based fine particles are composed of one or more fine particles of Al, Ti, Si, Ag, alumina, titanium oxide, and SiO ₂ . The metal or metal oxide-based fine particles listed here can be dispersed and confused evenly when they are mixed with the above-mentioned precursor containing the silicone resin as the main agent, without agglomerating among the fine particles. It is an example. The metal or metal oxide fine particles include ultrafine particles having an average particle diameter of about 1 nm to about 50 nm.

Hereinafter, examples of the present invention will be described more specifically.
FIG. 1 is a diagram showing a schematic configuration of an example of a container for evaluating hydrogen storage characteristics according to an embodiment of the present invention. In the container for evaluating hydrogen storage characteristics shown in FIG. 1, the pressure resistant container 1 is filled with a weighed hydrogen storage material, and then the container for evaluating hydrogen storage characteristics is weighed. Further, although the pressure vessel 1 is not shown, it may be cooled to a constant temperature as required by a cooling device or the like. A hydrogen cylinder (not shown) is connected to the pressure vessel 1 through a valve 2, and the valve 2 is opened, and hydrogen gas is filled up to a predetermined pressure from the direction of the white arrow. The pressure is measured by the pressure gauge 3, and after holding at a predetermined pressure for a predetermined time, the valve 2 is closed. Next, after removing the hydrogen cylinder, this hydrogen storage characteristic evaluation container is weighed, and the hydrogen storage capacity is calculated from the difference from the weight before hydrogen aeration, and the hydrogen storage capacity is calculated.

In this example, the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1, and 0.1 ≦ n ≦ A number in the range of 0.6, x and y are x + 2y = 4 and a number in the range of 0.2 ≦ x ≦ 1.5, z is an integer of z ≧ 25), or this A material containing metal or metal oxide fine particles is used as a precursor.

  The precursor is usually m in the above general formula, n is m + n = 1 and about 0.1 ≦ n ≦ 0.6, x and y are x + 2y = 4 and 1 ≦ x ≦ 2, and z is 3000 ≧. Preferably, a silicone resin represented by z ≧ 20 or a solution obtained by dissolving this in an organic solvent such as toluene or xylene, or a material obtained by adding metal or metal oxide fine particles thereto to 230 ° C. or lower is preferable. Is heated at a temperature of 60 ° C. to 200 ° C., more preferably 60 to 160 ° C. for several hours to several tens of hours, and a condensation polymerization reaction is carried out while evaporating the solvent, or at least once during that time, a vacuum heat treatment is performed at In the following, the temperature is preferably 60 ° C. to 200 ° C., more preferably 60 ° C. to 160 ° C., and the degree of vacuum may be as low as several thousand Pa, but the degree of vacuum is preferably 100 Pa to 1P. Obtained by performing a reduced pressure of degree. When a solution dissolved in an organic solvent such as toluene or xylene is used, about 10% or less of the organic solvent may remain in the precursor in addition to the main component of the silicone resin, but the characteristics of the obtained hydrogen storage material are deteriorated. It doesn't let you.

  Next, in the step of adjusting the precursor to a liquid state at a temperature of 230 ° C. or lower, it may be a temperature at which the solid silicone resin is in a liquid state at 230 ° C. or lower and usually at room temperature, preferably 60 ° C. It is maintained at a temperature of ˜200 ° C., more preferably 60 ° C. to 160 ° C., and a viscosity is preferably prepared as a paste of about 100 cps to 10000 cps.

  Next, the precursor prepared with the above viscosity is cast into an arbitrary mold by a known method such as a dispenser, spray, or screen printing, and thermally cured at a temperature of 200 ° C to 500 ° C.

  The temperature of the step of thermosetting at a temperature of 200 ° C. to 500 ° C. may be any temperature that cures in the range of 200 ° C. to 500 ° C., but a temperature of 300 ° C. to 450 ° C. is preferably used. In the case where metal or metal oxide fine particles are not added to the precursor, generally around 300 ° C. is used, and in the case where metal or metal oxide fine particles are added, around 400 ° C. is generally used.

  A hydrogen storage material is obtained by the thermosetting step. Then, although it depends on the method of use, it is used after being granulated by mechanical pulverization after the step of thermosetting. A mechanically pulverized material such as a mortar or ball mill is used after classifying the particle size according to the method of use. The particle size is preferably about 0.05 mm to 5 mm, more preferably about 0.1 mm to 2 mm. The granular material finally obtained can be used by being filled in a predetermined cylinder and incorporated in a desired apparatus.

  Hereinafter, the present invention will be described in more detail with reference to preferred examples. However, the present invention is not limited to these examples, and each element may be replaced or replaced within a range in which the object of the present invention is achieved. Also includes those in which design changes and process order changes have been made.

(Example 1)
(Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1 and n is about 0.3, x and y are x + 2y = 4 and x is about 1.3 and z is an integer of about 20 to 80. A solution of 120 g of a silicone resin dissolved in 80 g of toluene is heated to 120 ° C. to evaporate the toluene, and about 10 hours. A condensation polymerization reaction is performed. Next, the reaction product is transferred onto a hot plate in a vacuum chamber and evacuated while the hot plate is heated. Defoaming is performed at a vacuum degree of about 1 Pa in a vacuum chamber and a hot plate temperature of 140 ° C. for 60 minutes. As a result, (Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1, and n is about 0.3, x and y are A precursor based on a silicone resin in which x + 2y = 4, x is about 0.7, and z is an integer of z ≧ 25 is obtained. Next, the atmosphere was returned to the atmosphere while cooling the hot plate, and then heated again to 100 ° C. to obtain a paste-like precursor having a viscosity of 100 cps. This paste-like precursor was solid-printed on a 5 mm thick Teflon sheet, placed in a firing furnace, heated once in the atmosphere at 220 ° C. for 1 hour, then heated to 300 ° C. and fired for another 1 hour. A sheet-like film having no crack of about 2 mm was prepared. Next, the obtained film was mechanically pulverized in a mortar, and the obtained granular material was classified to about 0.1 mm to 1 mm by a sieve. Next, 40 g of the finally obtained granular material was weighed and filled in the pressure vessel 1 to evaluate the hydrogen storage characteristics. The measurement was performed as described above with reference to FIG. 1 (a diagram showing a schematic configuration of an example of a container for evaluating hydrogen storage characteristics according to an embodiment of the present invention). Here, the pressure vessel 1 was cooled to −20 ° C. by a cooling device. The pressure vessel 1 was opened with a valve 2 and filled with hydrogen gas to a pressure of 0.8 MPa from the direction of the white arrow. The pressure was measured by a pressure gauge 3 and maintained at a pressure of 0.8 MPa for 30 minutes, and then the valve 2 was closed. Next, after removing the hydrogen cylinder, the container for evaluating hydrogen storage characteristics was weighed, the amount of hydrogen stored was determined from the difference from the weight before hydrogen aeration, and the hydrogen storage capacity was calculated. The measurement results are shown in Table 1.

(Example 2)
(Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1 and n is about 0.5, x and y are x + 2y = 4 and x is about 1.9, z is about 1000 to 2000, and a solution of 100 g of a silicone resin dissolved in 100 g of xylene is heated to 100 ° C. to evaporate xylene for about 10 hours. A condensation polymerization reaction is performed. Next, the reaction product is transferred onto a hot plate in a vacuum chamber and evacuated while the hot plate is heated. Defoaming is performed for 60 minutes at a vacuum degree of about 1 Pa and a hot plate temperature of 120 ° C. As a result, (Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1, and n is about 0.5, x and y are A precursor based on a silicone resin in which x + 2y = 4, x is about 1.0, and z is an integer of z ≧ 1000 is obtained. Next, the atmosphere was returned to the atmosphere while cooling the hot plate, and then heated again to 120 ° C. to obtain a paste-like precursor having a viscosity of 100 cps. This paste-like precursor was applied by solid printing onto a 5 mm thick Teflon sheet, placed in a baking furnace, heated once in the atmosphere at 220 ° C. for 1 hour, then heated to 350 ° C. and further baked for 1 hour. A sheet-like film having no cracks of about 2 mm was prepared. Next, the obtained film was mechanically pulverized in a mortar, and the obtained granular material was classified into about 0.1 mm to 1 mm by a sieve. Next, 30 g of the finally obtained granular material was weighed and filled in the pressure vessel 1, and the hydrogen storage characteristics were evaluated in the same manner as in Example 1. The measurement results are shown in Table 1.

(Example 3)
(Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1 and n is about 0.3, x and y are x + 2y = 4 and a silicone resin 120 g represented by an integer of about 1.3 to about 80 and z is dissolved in 80 g of toluene, and ultrafine silica (SiO ₂₎ having an average particle size of about 12 nm is dissolved in this solution. ) (Trade name: Aerosil Degussa Co., Ltd.) 4 g is added and toluene is evaporated while this solution is heated to 120 ° C. and subjected to a condensation polymerization reaction for about 10 hours. Next, the reaction product is transferred onto a hot plate in a vacuum chamber and evacuated while the hot plate is heated. Defoaming is performed at a vacuum degree of about 1 Pa in a vacuum chamber and a hot plate temperature of 140 ° C. for 60 minutes. As a result, (Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1, and n is about 0.3, x and y are A precursor containing ultrafine silica particles with a silicone resin represented by an integer of x + 2y = 4, x being about 0.7, and z being an integer of z ≧ 25 is obtained. Next, the atmosphere was returned to the atmosphere while cooling the hot plate, and then heated again to 100 ° C. to obtain a paste-like precursor having a viscosity of 100 cps. This paste-like precursor was solid-printed on a 5 mm thick Teflon sheet, placed in a firing furnace, heated once in the atmosphere at 220 ° C. for 1 hour, then heated to 400 ° C. and fired for an additional hour. A sheet-like film having no crack of about 2 mm was prepared. Next, the obtained film was mechanically pulverized in a mortar, and the obtained granular material was classified to about 0.1 mm to 1 mm by a sieve. Next, 40 g of the finally obtained granular material was weighed and filled in a pressure vessel 1 and evaluated for hydrogen storage characteristics in the same manner as in Example 1. The measurement results are shown in Table 1.

Example 4
(Si (Me _m Ph _n ) _x O _y ) _z (where Me is a methyl group and Ph is a phenyl group), m and n are m + n = 1 and n is about 0.3, x and y are x + 2y = 4 except that 120 g of a silicone resin represented by an integer of about 1.3 and z is about 20 to 80 is dissolved in 80 g of toluene, and 20 g of silica fine particles having an average particle size of about 20 μm are added to this solution. Prepared the hydrogen storage material of the present invention in the same manner as in Example 3, and evaluated the hydrogen storage characteristics. The measurement results are shown in Table 1.

Next, a standard example will be described.
(Comparative example)
40 g of commercially available granular activated carbon was weighed and filled in a pressure vessel 1 and evaluated for hydrogen storage characteristics in the same manner as in Example 1. The measurement results are shown in Table 1.

  From the above examples, the hydrogen storage material of the present invention showed a significantly larger hydrogen storage capacity than the commercially available activated carbon. Furthermore, when the metal resin-based fine particles are contained in a precursor mainly composed of a silicone resin (Examples 3 and 4), the hydrogen storage capacity is improved as compared with the case where they are not contained (Examples 1 and 2). did.

In the present invention, the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0. .6, x and y are x + 2y = 4 and 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25). By forming the precursor into a liquid state at a temperature of 230 ° C. or lower and a step of thermosetting at a temperature of 200 ° C. to 500 ° C., the surface has a fine porous structure, and has a temperature of 300 ° C. or higher. A hydrogen storage material having heat resistance and excellent water resistance can be provided.

  Accordingly, it is possible to provide a hydrogen storage material that can efficiently store hydrogen and can be safely handled under conditions that do not greatly deviate from normal temperature and normal pressure. Therefore, application to a hydrogen fuel tank for a fuel cell, which is a power source of a fuel cell vehicle, is enhanced, and its industrial benefit is extremely large.

  Further, it is possible to provide a hydrogen storage material that can efficiently store hydrogen and can be handled safely under conditions that do not greatly deviate from normal temperature and normal pressure.

  The present invention can be used as a hydrogen storage material.

It is a figure which shows schematic structure of an example of the container for hydrogen storage characteristic evaluation which can be used for this invention. It is a figure which shows the structure corresponding to the micropore in the surface of the hydrogen storage material by this Embodiment.

Explanation of symbols

1 ... pressure vessel, 2 ... valve, 3 ... pressure gauge.

Claims (14)

It has a structure mainly composed of a trifunctional basic unit represented by the general formula RSiO _1.5 (R represents a methyl group or a phenyl group) and a tetrafunctional basic unit represented by SiO ₂ . A hydrogen storage material having a microporous structure on the surface.   The porous structure includes macropores, mesopores formed in the macropores, and micropores formed at least on the surface of the mesopores and adsorbing hydrogen molecules. The hydrogen storage material according to claim 1. The micropore has a tetracyclosiloxane structure represented by the chemical formula (2) in which a siloxane bond (—O—Si—O—) is inserted between the left and right Si atoms in the chemical formula (1). The hydrogen storage material according to claim 2, wherein hydrogen molecules are taken into the tetracyclosiloxane structure.

The hydrogen storage material has the general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n) ≦ 0.6 number, x and y are x + 2y = 4 and 0.2 ≦ x ≦ 1.5, z is an integer of z ≧ 25) The hydrogen storage material according to any one of claims 1 to 3, wherein the precursor is made to contain metal or metal oxide fine particles.   The hydrogen storage material according to claim 4, wherein the proportion of the metal or metal oxide-based fine particles is preferably 0.5 to 20%, more preferably 1 to 10%. Particles of the metal or metal oxide system, Al, Ti, Si, Ag, alumina, hydrogen storage of claim 5, characterized in that it consists of any one or more of the fine particles of titanium oxide and SiO ₂ material.   The hydrogen storage material according to claim 6, wherein the metal or metal oxide-based fine particles include ultra fine particles having an average particle diameter of about 1 nm to about 50 nm.   The hydrogen storage material is a powder material having a particle size of about 0.05 mm to 5 mm, more preferably about 0.1 mm to 2 mm, according to any one of claims 1 to 7. Hydrogen storage material. General formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0.6. And x, y is a number in the range of x + 2y = 4 and 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25). And a step of adjusting to a liquid state at a temperature of 230 ° C. or lower, and a step of thermosetting at a temperature of 200 ° C. to 500 ° C. The general formula (Si (Me _m Ph _n ) _x O _y ) _z (where Me represents a methyl group, Ph represents a phenyl group, m and n are m + n = 1 and 0.1 ≦ n ≦ 0.6) The number of ranges, x and y are x + 2y = 4 and the number is in the range of 0.2 ≦ x ≦ 1.5, and z is an integer of z ≧ 25). The method for producing a hydrogen storage material according to claim 9, further comprising metal or metal oxide fine particles. 11. The metal or metal oxide-based fine particle according to claim 9, wherein the metal or metal oxide-based fine particle includes one or more fine particles of Al, Ti, Si, Ag, alumina, titanium oxide, and SiO ₂ . A method for producing a hydrogen storage material.   12. The method for producing a hydrogen storage material according to claim 11, wherein the metal or metal oxide fine particles include ultra fine particles having an average particle diameter of about 1 nm to about 50 nm.   The hydrogen storage material according to any one of claims 9 to 12, comprising a step of performing a vacuum heat treatment at least once at a temperature not higher than a temperature at which the precursor containing the silicone resin as a main ingredient is cured. Manufacturing method.   The method for producing a hydrogen storage material according to any one of claims 9 to 13, further comprising a step of performing mechanical pulverization after the step of thermosetting.

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