JP7125710B2 - Method for producing hydrogen-supported powder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing hydrogen-supported powder having excellent hydrogen-carrying capacity and hydrogen-releasing capacity at low cost.

In recent years, hydrogen water has been provided by various companies as a food product that has the potential to effectively remove active oxygen, suppress cancer, diet, and the like, and expectations for hydrogen water are increasing. Hydrogen water is water in which the concentration of hydrogen molecules (hydrogen gas) is increased, and various materials that can be used for producing hydrogen water are being investigated.

As a method for producing high-concentration hydrogen water, for example, hydrogen in a gaseous state is pressurized to 1 atm or more and less than 10 atm, mixed with water in a container, and the water and the hydrogen are brought into contact (Patent Document 1) and a method of dispersing a gas such as hydrogen in a liquid solvent such as water in the form of ultrafine bubbles (Patent Document 2).

In recent years, as one form of uptake of hydrogen molecules, there has been developed a method in which hydrogen is supported on a solid carrier, and hydrogen molecules are released simultaneously with contact with water. Hydrogen-supported carriers can be used to prepare hydrogen water when necessary, and if a naturally-derived calcium carbonate-based carrier such as coral calcium is used, hydrogen-supported carriers can be drunk as they are. (Patent Document 3).

The present inventors have developed a method of heat-treating a calcium carbonate-containing powder in two steps as a method for producing a hydrogen-supported powder having excellent hydrogen-supporting and hydrogen-releasing capabilities (Patent Documents 4 and 5).

JP 2015-150472 A Japanese Patent No. 5746411 Japanese Patent No. 4404657 Japanese Patent No. 6244051 Japanese Patent No. 6337192

In general, hydrogen molecules have a very small molecular size, so even if hydrogen water is produced, the hydrogen molecules in hydrogen water easily permeate the container, and the dissolved hydrogen concentration tends to decrease over time. As a container for hydrogen water, a container with low hydrogen permeability such as an aluminum laminate container or an aluminum can is adopted. However, even if a container with low hydrogen permeability is used, hydrogen dissolved in the container rapidly escapes when the container is opened, so it is not easy to store hydrogen water for a long time after opening. Therefore, it is preferable to use a hydrogen-carrying powder that can prepare hydrogen water as needed rather than hydrogen water in which hydrogen is dissolved from the beginning. Such a hydrogen-carrying powder can be added to foods to generate hydrogen in vivo.
On the other hand, even if hydrogen molecules _are to be supported on a solid carrier, for example, in the production method described in Patent Document ₃ , after oxidizing and firing at 700 ° C. for 4 hours, 650 Since reduction firing for 4 hours at °C is essential and the heat treatment requires a great deal of cost, a hydrogen-supported powder cannot be produced at a low cost. Further, as described above, the present inventors have also developed a method for producing a hydrogen-supported powder, but there is a demand for a hydrogen-supported powder that is more excellent in hydrogen-supporting ability and hydrogen-releasing ability.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a new method for producing hydrogen-supported powder having excellent hydrogen-supporting and hydrogen-releasing capabilities at low cost.

The present inventors have made intensive studies to solve the above problems. As a result, the present inventors have found that hydrogen-supported powder having excellent hydrogen-supporting and hydrogen-releasing capabilities can be easily produced by using a powder containing mother-of-pearl as a raw material and subjecting the powder to high-pressure hydrogen treatment, thereby completing the present invention.
The present invention is shown below.

[1] A method for producing a hydrogen-supported powder, comprising a step of subjecting a powder containing a nacre layer to high-pressure hydrogen treatment in a hydrogen atmosphere.
[2] The method for producing a hydrogen-supported powder according to [1] above, which includes a step of calcining the powder containing the mother-of-pearl before the high-pressure hydrogen treatment step.
[3] The method for producing a hydrogen-supported powder according to [2] above, wherein the firing temperature is 200°C or higher and 700°C or lower.
[4] The method for producing a hydrogen-supported powder according to any one of [1] to [3] above, wherein the pressure of the hydrogen atmosphere in the high-pressure hydrogen treatment step is 0.5 MPa or more and 50 MPa or less.
[5] The method for producing a hydrogen-supported powder according to any one of [1] to [4] above, wherein the hydrogen concentration in the hydrogen atmosphere in the high-pressure hydrogen treatment step is 80 vol% or more.
[6] The method for producing a hydrogen-supported powder according to any one of [1] to [5] above, wherein the temperature in the high-pressure hydrogen treatment step is 5°C or higher and 40°C or lower.

According to the method of the present invention, a powder containing mother-of-pearl is selected as a raw material to easily produce a hydrogen-supported powder having excellent hydrogen-supporting ability and hydrogen-releasing ability. By adding such a hydrogen-supporting powder to water, hydrogen water with a relatively high concentration can be easily prepared, and a relatively large amount of hydrogen can be generated in vivo by direct ingestion. Therefore, the present invention provides highly-concentrated hydrogen water, which is an effective health food and drink that has reducing power and can improve diseases and disorders caused by oxidative conditions in the body by constant intake. It is industrially very useful as a hydrogen-supported powder that can be prepared at a low cost and can be easily produced.

<Method for producing hydrogen-supported powder>
A method for producing a hydrogen-supported powder according to the present invention is characterized by including a step of subjecting a powder containing a mother-of-pearl to high-pressure hydrogen treatment in a hydrogen atmosphere.

The nacreous layer refers to the iridescent layer attached to the inside of the shell, for example. Complex. However, whereas the crystals of aragonite (aragonite) are orthorhombic, the mother-of-pearl has a polygonal or circular cross-section centered on a pseudo-hexagonal system, with a width of 5-20 μm and a thickness of 0.3-1 mm. It is an aggregate of microcrystals of 0.5 μm. Generally, calcium carbonate crystals are brittle, but nacreous layers have a structure in which microcrystals of various sizes are adhered by adhesive components such as chitin and protein, so the Young's modulus is approximately It is very tough as 70 GPa.

According to experimental findings by the present inventors, when pure water calcium carbonate powder is used as a raw material, there is room for improvement in the hydrogen-carrying capacity and hydrogen-releasing capacity of the resulting hydrogen-carrying powder. Even if the hydrogen pressure was increased at that time, the increase in the amount of hydrogen carried was not as much as expected. On the other hand, when the mother-of-pearl-containing powder was used, it was found that the hydrogen-carrying capacity and the hydrogen-releasing capacity tended to improve according to the hydrogen pressure during the high-pressure hydrogen treatment. The reason for this is not necessarily clear, but it is thought that there is some structural feature that efficiently holds hydrogen molecules in the interstices of the microcrystals of various sizes that make up the nacre layer.

The powder containing mother-of-pearl is not particularly limited as long as it is a powder made of a substance containing mother-of-pearl, and for example, pearl powder can be used. As the pearl powder, a substance of biological origin is preferred. By using a biological pearl powder as a raw material, safety is ensured even if the hydrogen-supported powder is ingested. From this point of view, the biological pearl powder is preferably at least one powder selected from the group consisting of pearls, shells of bivalves and gastropods, and nautilus shells. Since pearls have nacreous layers on the surface and seashells have nacreous layers on the inside, they are suitable as raw materials for the present invention.

The size of the mother-of-pearl-containing powder used as a raw material is not particularly limited. It is considered that the smaller the diameter of the powder, the larger the surface area, and the more efficiently the hydrogen molecules can be supported. On the other hand, if the powder diameter is excessively small, the energy required for pulverization may become excessively large. The average particle size is more preferably 10 μm or more, still more preferably 20 μm or more, more preferably 200 μm or less or 100 μm or less, and even more preferably 60 μm or less. The average particle size in the present disclosure means the median size obtained from the volume-based cumulative particle size distribution, that is, the particle size (D50) corresponding to 50% of the cumulative volume. The volume-based cumulative particle size distribution and average particle size can be measured, for example, by a laser diffraction scattering method.
The particle size of the mother-of-pearl-containing powder and the hydrogen-supported powder described below can be appropriately adjusted by pulverization, classification, or the like.

As mentioned above, the mother-of-pearl layer has a unique structure in which plate-like microcrystals of calcium carbonate with an aragonite structure are laminated, and organic components such as chitin and protein exist as adhesive layers in the gaps between the microcrystals. ing. By removing at least part of the adhesive layer composed of this organic component, the amount of hydrogen carried is considered to be further increased. The method for removing the adhesive layer is not particularly limited as long as the adhesive layer can be removed.

The firing method may be any method as long as it can thermally decompose the adhesive layer, but since the thermal decomposition temperature of the adhesive layer is approximately 200 to 250° C., firing at 200° C. or higher is preferable. Moreover, since the thermal decomposition temperature of calcium carbonate, which is the main component, is approximately 800°C, the temperature is preferably 800°C or lower. The temperature is preferably 250° C. or higher, more preferably 300° C. or higher, preferably 700° C. or lower, more preferably 600° C. or lower, and even more preferably 550° C. or lower or 500° C. or lower. Moreover, the firing atmosphere is not particularly limited, and examples thereof include air, oxygen, inert gases such as nitrogen and rare gases, and carbon dioxide. The firing time may be adjusted as appropriate, and may be, for example, 1 minute or more and 10 hours or less.

In the chemical conversion treatment, the adhesive layer can be dissolved and removed with a treating agent. Since the adhesive layer is composed of chitin and protein, it may be treated with a treating agent capable of dissolving them but not dissolving calcium carbonate. Examples thereof include treatment with an alkaline aqueous solution, enzymes, surfactants, etc., but it is preferable to use an alkaline aqueous solution that can be treated in a short time at a low cost, and alkalis such as sodium hydroxide, potassium hydroxide and lithium hydroxide. Examples include metal hydroxides and amines such as ammonia, methylamine, and ethanolamine. Among them, sodium hydroxide or potassium hydroxide is preferable from the viewpoint of toxicity to the human body. After the adhesive layer is removed with the treating agent, it can be used in a high-pressure hydrogen treatment step, for example, by appropriately washing and then drying.

In the present invention, before the high-pressure hydrogen treatment step, a step of replacing the gas after enclosing the mother-of-pearl-containing powder in an airtight container may be performed. The gas replacement step is a step of removing moisture and gas adsorbed on the surface of the mother-of-pearl-containing powder, and the method of gas replacement is not particularly limited. Substitution operations are preferred. As the gas, hydrogen gas is preferably used in addition to an inert gas such as nitrogen or argon.

In the high-pressure hydrogen treatment step, for example, the mother-of-pearl-containing powder may be enclosed in a pressure-resistant hermetic container, and hydrogen gas may be pressurized under predetermined conditions.

The temperature in the high-pressure hydrogen treatment step can be -200°C or higher and 100°C or lower. Since the adsorption of hydrogen to the mother-of-pearl-containing powder is mainly physical adsorption, it can be said that the lower the temperature, the greater the amount of hydrogen carried. On the other hand, since the hydrogen-supported powder is often stored at room temperature, it can be said that the temperature in the high-pressure hydrogen treatment step should be close to room temperature, which is advantageous in terms of production efficiency. The temperature is preferably the boiling point of liquid nitrogen (−196° C.) or higher, more preferably −10° C. or higher, even more preferably 0° C. or higher, preferably 80° C. or lower, and even more preferably 60° C. or lower. Further, if the temperature is normal temperature of 5° C. or more and 40° C. or less, there is no need to adjust the temperature, and the manufacturing cost can be further reduced.

The high pressure hydrogen treatment step is carried out under a hydrogen atmosphere. The hydrogen concentration in the hydrogen atmosphere may be adjusted as appropriate, but can be, for example, 5 vol% or more. Since it can be said that the higher the hydrogen concentration, the higher the hydrogen carrying efficiency, the upper limit can be 100 vol%. The hydrogen concentration is preferably 30 vol% or more, more preferably 50 vol% or more, still more preferably 80 vol% or more or 90 vol%, and preferably 95 vol% or less. In addition, in the hydrogen atmosphere, an inert gas such as nitrogen, argon, or carbon dioxide is preferable as the balance other than hydrogen gas. In the high-pressure hydrogen treatment process, since the hydrogen concentration can be easily adjusted, the high-pressure hydrogen treatment may be performed while a gas having a controlled hydrogen concentration is circulated.

The pressure in the high-pressure hydrogen treatment step is above atmospheric pressure, preferably 0.2 MPa or more or 0.5 MPa or more, more preferably 1 MPa or more, still more preferably 2 MPa or more, preferably 100 MPa or less, more preferably 50 MPa or less, More preferably, it is 20 MPa or less. The higher the pressure, the better the performance of the obtained hydrogen-supported powder, and the higher the amount of hydrogen supported. In particular, in the method of the present invention, by using mother-of-pearl-containing powder obtained by removing at least part of the adhesive layer of the mother-of-pearl as a raw material, the effect of carrying hydrogen by using a high-pressure hydrogen atmosphere is further enhanced.

The time of high-pressure hydrogen treatment may be adjusted as appropriate, but is preferably 0.5 hours or longer, more preferably 0.75 hours or longer, still more preferably 1 hour or longer, preferably 2 hours or shorter, and more preferably 1.75 hours. It is preferable to carry out for 1.5 hours or less, more preferably for 1.5 hours or less. By carrying out the high-pressure hydrogen treatment step for a sufficient period of time, a hydrogen-supported powder supporting hydrogen at a high concentration is produced.

<Hydrogen-supporting powder>
The hydrogen-supported powder according to the present invention is produced by the method for producing a hydrogen-supported powder described above. Although the present inventors have made various studies, the full picture of the hydrogen-supported powder obtained by the above-described production method has not been elucidated, and it has not yet been specified what kind of structure of the hydrogen-supported powder directly affects the effects of the present invention. I haven't been able to. However, the hydrogen-supported powder obtained by the above-described production method generates a desired amount of hydrogen gas upon contact with moisture, as shown in the results of Examples below. The structural features of the hydrogen-supported powder are described in detail.

In the present disclosure, “hydrogen-supported powder in which hydrogen is physically adsorbed” specifically refers to mother-of-pearl-containing powder whose crystal structure does not change due to pressurization and high-temperature hydrogen treatment, more specifically, It is defined as a powder characterized by having porosity or mesopores and reversible desorption of hydrogen with respect to each pressure when pressurized with hydrogen. Since the adsorption force of the hydrogen-supported powder in which hydrogen is physically adsorbed is mainly due to van der Waals force, the hydrogen-supported powder is characterized in that hydrogen can be desorbed by evacuation.

The state in which hydrogen is physically adsorbed refers to, for example, an adsorption state in which hydrogen is weakly bound to the surface of the powder by Van der Waals force or the like without the crystal structure being changed by the high-pressure hydrogen treatment. In other words, charge exchange does not take place in the hydrogen-supporting powder, and hydrogen is reversibly desorbed and is in an adsorbed state without dissociation. The crystal structure can be confirmed by the Hanawalt method using an X-ray diffractometer, and the adsorption state can be confirmed by the IUPAC classification according to the profile shape of the adsorption isotherm or by the JIS H7201 pressure-composition isotherm (PCT line) measurement method.

The average particle size of the hydrogen-supporting powder is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and preferably 100 μm or less, more preferably 50 μm or less, still more preferably 20 μm or less.

<Application of hydrogen-supported powder>
The hydrogen-supporting powder according to the present invention can be used in various applications. One application example includes foods containing the hydrogen-carrying powder. Examples of the foods include hydrogen supplements in which the hydrogen-supported powder is encapsulated or tableted so that it can be directly orally administered; processed foods such as candies, gums, gummies, etc. containing the hydrogen-supported powder; In addition, since the hydrogen-supported powder of the present invention releases hydrogen molecules when it comes into contact with water, the hydrogen-supported powder is added to drinking water such as tap water, mineral water, deep sea water, and soft drinks. It can also be preferably used for water production.

Other application examples include cosmetics and fertilizers containing hydrogen-bearing powders. Cosmetics containing the hydrogen-carrying powder according to the present invention include, for example, skin care products such as facial cleansers, lotions, serums, milky lotions, creams, and lotions; oral care products such as liquids and mouthwashes;

The fertilizer containing the hydrogen-carrying powder according to the present invention is, for example, rice; fruit trees such as figs, cherries, and grapes; vegetables such as eggplant, pumpkin, cucumber, tomato, basil, green pepper, corn, and zucchini; It can be used, and according to the fertilizer, effects such as larger fruits, less disease, and faster fruiting are exhibited. In addition, it has been pointed out that active oxygen is involved in the death of plants (Takagi Daisuke et al., Plant Physiology, 171(3), p.1626-1634). If fertilizers are used, they are expected to have the effect of prolonging the life of plants due to the effect of removing active oxygen.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and can be modified appropriately within the scope that can conform to the gist of the above and later descriptions. It is of course possible to implement them, and all of them are included in the technical scope of the present invention.

Example 1
Pearl powder (manufactured by Doi Shinju Co., Ltd.) was placed in a dryer and dried at 100° C. for 12 hours. 1.0 g of the dried pearl powder thus obtained was placed in a 40 mL pressure-resistant container, and after the pressure was reduced to 0.001 MPa with a vacuum pump, hydrogen gas was introduced to return the pressure to normal pressure, which was repeated three times. Then, 1 MPa of hydrogen gas was introduced, and high-pressure hydrogen treatment was performed at 20 to 22° C. for 1 hour. After that, the pressure was returned to normal pressure to obtain about 1.0 g of hydrogen-supported powder.

Examples 2 and 3
A hydrogen-supported powder was produced in the same manner as in Example 1, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 4
A hydrogen-supported powder was produced in the same manner as in Example 1, except that pearl powder (manufactured by Doi Pearl Co., Ltd.) was baked in the air at 300° C. for 10 minutes in a muffle furnace instead of drying.

Examples 5 and 6
A hydrogen-supported powder was produced in the same manner as in Example 4, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 7
A hydrogen-supported powder was produced in the same manner as in Example 4, except that the sintering temperature was 400°C.

Examples 8 and 9
A hydrogen-supported powder was produced in the same manner as in Example 7, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 10
A hydrogen-supported powder was produced in the same manner as in Example 4, except that the sintering temperature was 450°C.

Examples 11 and 12
A hydrogen-supported powder was produced in the same manner as in Example 10, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 13
A hydrogen-supported powder was produced in the same manner as in Example 4, except that the sintering temperature was 500°C.

Examples 14 and 15
A hydrogen-supported powder was produced in the same manner as in Example 13, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Comparative example 1
A hydrogen-supporting powder was produced in the same manner as in Example 1, except that calcium carbonate (manufactured by Kojundo Chemical Laboratory Co., Ltd., purity: 99.99%) was used instead of pearl powder (manufactured by Doi Pearl Co., Ltd.).

Comparative Examples 2 and 3
A hydrogen-supported powder was produced in the same manner as in Example 10, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 10 MPa.

Test Example 1: Evaluation of amount of hydrogen generated (1) Preparation of sample Put each hydrogen-supporting powder (3 g) in a vial with a capacity of 40 mL, add pure water (15 mL), cover, and place the vial at 35 ° C. was warmed to The vial was shaken for 24 hours while maintaining 35°C.

(2) Analysis by Gas Chromatography The gas phase in the vial after shaking for 24 hours was analyzed by gas chromatography. The conditions for gas chromatography are as follows.
Gas chromatography: "Tracera (registered trademark)" manufactured by Shimadzu Corporation
Detector: Barrier Discharge Ionization Detector (BID)
Column: "MICROPACKED ST" manufactured by Shinwa Kako Co., Ltd.
Column temperature: Maintained at 35°C for 2.5 minutes - Raised temperature to 250°C at 20°C/min - Raised temperature to 270°C at 15°C/min - Maintained at 270°C for 5.42 minutes (Total: 20 minutes)
Gas injection method: gas-tight syringe Pressure program: 250 kPa maintained for 2.5 minutes - pressurized at 15 kPa/min up to 400 kPa (by He)
Injection Mode: Split (1:10)
Vaporization chamber temperature: 150°C
Detector temperature: 280°C
Discharge gas flow rate: 70 mL/min
Injection volume: 100 μL

(3) Calculation of hydrogen generation amount When the hydrogen concentration measured in (2) is A (ppm) and the volume of the gas phase in the vial is V (mL), the gas phase V (mL) contains The hydrogen capacity V _H2 is represented by the formula (E-1).
_VH2 = A (ppm) x V (mL)
= A x V x 10 ^-3 (μL) ・・・ (E-1)
Since 3 g of the hydrogen-supported powder was used in this test, the amount of hydrogen gas generated per 1 g of the hydrogen-supported powder is obtained by the formula (E-2).
Amount of hydrogen gas generated per 1 g of hydrogen-supported powder = A x V x 10 ^-3 (μL)/3 (g)
= A x (40-15) x 10 ^-3 (µL)/3 (g)
= A x 25 x 10 ^-3 /3 (μL/g) (E-2)
Table 1 shows the results.

As the results shown in Table 1 show, the amount of hydrogen gas generated by contact with moisture can be increased by subjecting the mother-of-pearl-containing powder to high-pressure hydrogen treatment, compared to the case of using calcium carbonate as a raw material. I found out. Moreover, the amount of hydrogen gas generated was remarkably increased by increasing the hydrogen pressure in the high-pressure hydrogen treatment. In addition, it was shown that the amount of hydrogen supported by air firing of the mother-of-pearl-containing powder increased dramatically, and as a result, the amount of hydrogen gas generated also increased dramatically. The reason for this is thought to be that the adhesion layer of the mother-of-pearl-containing powder is thermally decomposed and removed, and the resulting specific structure contributes to the amount of hydrogen carried.

Example 16
Pearl powder (manufactured by Orange Flower Co., Ltd., 500 mesh) was placed in a dryer and dried at 100° C. for 12 hours. 1.0 g of the dried pearl powder thus obtained was placed in a 40 mL pressure-resistant container, and after the pressure was reduced to 0.001 MPa with a vacuum pump, the pressure was returned to normal pressure by introducing hydrogen gas, which was repeated three times. Then, 1 MPa of hydrogen gas was introduced, and high-pressure hydrogen treatment was performed at 20 to 22° C. for 1 hour. After that, the pressure was returned to normal pressure to obtain about 1.0 g of hydrogen-supported powder.

Examples 17 and 18
A hydrogen-supported powder was produced in the same manner as in Example 16, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 19
A hydrogen-supported powder was produced in the same manner as in Example 16, except that instead of drying, a muffle furnace was used and the pearl powder was calcined at 300° C. in the air for 10 minutes.

Examples 20 and 21
A hydrogen-supported powder was produced in the same manner as in Example 19, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 22
A hydrogen-supported powder was produced in the same manner as in Example 19, except that the sintering temperature was 400°C.

Examples 23 and 24
A hydrogen-supported powder was produced in the same manner as in Example 22, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 25
A hydrogen-supported powder was produced in the same manner as in Example 19, except that the sintering temperature was 450°C.

Examples 26 and 27
A hydrogen-supported powder was produced in the same manner as in Example 25, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 28
A hydrogen-supported powder was produced in the same manner as in Example 19, except that the sintering temperature was 500°C.

Examples 29 and 30
A hydrogen-supported powder was produced in the same manner as in Example 28, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Example 31
A hydrogen-supported powder was produced in the same manner as in Example 19, except that the sintering temperature was 600°C.

Examples 32 and 33
A hydrogen-supported powder was produced in the same manner as in Example 31, except that the pressure of hydrogen gas in the high-pressure hydrogen treatment was changed to 5 MPa or 12 MPa.

Test Example 2: Evaluation of Amount of Hydrogen Generated In the same manner as in Test Example 1, the amount of hydrogen generated from the hydrogen-supported powders of Examples 16 to 33 was evaluated. Table 2 shows the results.

As the results shown in Table 2 show, even when other nacre-containing powders were used, it was found that high-pressure hydrogen treatment could increase the amount of hydrogen gas generated by contact with moisture. Moreover, the amount of hydrogen gas generated was remarkably increased by increasing the hydrogen pressure in the high-pressure hydrogen treatment. Even when the firing temperature of the mother-of-pearl-containing powder was increased to 600°C, a hydrogen-supported powder was obtained that generated hydrogen well, but the amount of hydrogen generated was greater when the firing temperature was 500°C.

Claims (5)

A method for producing a hydrogen-supported powder, comprising a step of subjecting a powder containing a mother-of-pearl to high-pressure hydrogen treatment at a temperature of 5°C or higher and 40°C or lower in a hydrogen atmosphere. 2. The method for producing a hydrogen-supported powder according to claim 1, further comprising a step of calcining the powder containing the mother-of-pearl before the high-pressure hydrogen treatment step. 3. The method for producing a hydrogen-supporting powder according to claim 2, wherein the temperature of the firing treatment is 200[deg.] C. or higher and 700[deg.] C. or lower. The method for producing a hydrogen-supported powder according to any one of claims 1 to 3, wherein the pressure of the hydrogen atmosphere in the high-pressure hydrogen treatment step is 0.5 MPa or more and 50 MPa or less. The method for producing a hydrogen-supported powder according to any one of claims 1 to 4, wherein the hydrogen concentration in the hydrogen atmosphere in the high-pressure hydrogen treatment step is 80 vol% or more.