JP2008071656A - Solution plasma reaction apparatus, and manufacturing method for nanomaterial using the solution plasma reaction apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solution plasma reaction apparatus by which a nanomaterial is manufactured efficiently while the production of hazardous waste is prevented inexpensively, and to provide a manufacturing method for a nanomaterial using the solution plasma reaction apparatus. <P>SOLUTION: The reaction apparatus includes a solution reaction bath 1, and a plasma generating electrode 2 placed in the solution reaction bath 1. The plasma generating electrode 2 is composed of a gas introducing pipe 3 disposed at the center, and a columnar electrode 4 disposed around the gas introduction pipe. A cooling medium introducing portion 5 is disposed at the center of the electrode 4, where the cooling medium introducing portion can be cooled by air or water. The columnar electrode 4 has a high-frequency input terminal 6 for applying high frequency from a high-frequency power supply, which high frequency input terminal extends from the outside of the electrode 4 to reach a cavity 9 at the center of the electrode 4. A gas coming in through the gas introducing pipe 3 is turned into plasma by an electric field introduced through the high frequency input terminal 6, and the plasma is introduced into a reaction solution 8 in the reaction bath 1, where part of the reaction solution turns into plasma to form solution plasma. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention uses a high-frequency electrode having a special shape and generates a plasma state in which a heat, electric field, radical species, and ultraviolet light are combined in a solution, and a raw material compound is dissolved or dissolved in the solvent by the plasma state. The present invention relates to a method for producing a nanomaterial from a dispersed reaction solution.

  Along with the development of power supply and electrode structure in recent years, techniques for generating plasma or discharge in a high-pressure gas atmosphere at or near atmospheric pressure and a solution such as an aqueous solution have been actively proposed. These phenomena in the gas phase are called atmospheric pressure plasma, and these phenomena in the liquid phase are called solution plasma. However, most of them use so-called corona discharge using high-voltage direct current or streamer discharge by a pulse power source having a pulse width of about nano to microseconds. They are applied to surface treatments such as decomposition of organic substances having a simple structure (for example, methane, nitric oxide, etc.) and destruction of the surface structure of low melting point organic compounds.

As an example of surface cleaning with atmospheric pressure plasma, the decomposition of low melting point organic substances due to the discharge phenomenon caused by the application of direct current to parallel plate electrodes and the surface cleaning by the synergistic effect of the blowing effect by the flowed gas have been proposed ( Patent Document 1). However, in general, in these discharge phenomena, only a simple decomposition reaction can occur mainly due to the low energy density of plasma. As described above, in the atmospheric pressure plasma or solution plasma using a direct current or pulse power source, the application range is mainly limited to the use of a phenomenon based on decomposition of a substance.
JP 2006-159209 A

  On the other hand, with regard to the material itself, with the development of industrial technology in recent years, fine particles having a diameter of about 1 nm to 1 μm or particles formed by depositing the fullerene, metal nanoparticles or thin films, inorganic nanoparticles or thin films It is possible to produce a film-like or film-like substance. In particular, substances with a crystal grain size of less than 10 nm are called single nano-level materials, and are used for secondary electron emission materials, illuminants, endotherms, catalysts, energy storage, battery electrodes, and separation classification. A wide range of applications such as filters or adsorbents have been attempted. Many of these can significantly improve their functions if their surfaces can be modified with other materials. However, it is known that the production of a material having such a fine structure is extremely difficult because it is necessary to strictly control the nucleation and the growth process.

  For example, it is known that fine particles having a size of about 1 to 10 nm can be produced by dissolving a metal salt in water and subjecting the metal salt to drying, calcination, or firing in a reducing atmosphere. However, in such a solution method, as the concentration of the solution increases, the density and size of the formed nuclei increase, so that the finally obtained particles increase. Therefore, in general, in order to obtain a single nano-level material, it is necessary to manufacture in a very dilute solution with a metal concentration of about o.o1 mol / l or less. For this reason, in order to obtain a single nano-level material in the solution method, a large amount of solvent is required, and the apparatus must be scaled up. In some cases, it is necessary to add a pH adjuster or a reducing agent. Generally, these additives are often harmful to the human body, so the solution cannot be drained as it is. These have led to an increase in the cost of the solution method, which should be essentially an inexpensive method.

In addition, many attempts have been reported to produce a single nano-level material by evaporating a metal under reduced pressure, referred to as a vapor phase method. Production of various material systems has been reported depending on the heating method and the like. However, all of these require a vacuum apparatus and the like, and thus an expensive apparatus is necessary for mass production. This has led to a significant increase in the cost of the gas phase method.
As an attempt to produce a single nano-level material at low cost by the solution method, a solution method for producing single nano-level silica particles has been proposed (see Patent Document 2). Since it is necessary to add ammonia as an agent, the waste liquid cannot be drained as it is.
In addition, as an attempt to produce a single nano-level material at a low cost by a gas phase method, there is an example of nanoparticle production using a laser ablation method (see Patent Document 3). Alternatively, since a vacuum apparatus is required to create an oxygen, ozone, water vapor, or ammonia atmosphere, there is a problem that an expensive apparatus is required.
As described above, the production method of a single nano-level material has problems of cost and generation of hazardous waste.
JP 2004-315300 A JP 2006-075979 A

  Therefore, the present invention eliminates these problems of the prior art and uses a solution plasma using a high-frequency power source to efficiently produce nanomaterials while preventing the generation of hazardous waste at low cost and The main purpose is to provide such a device.

As a result of intensive studies in view of the problems of the above prior art, the present inventor has adopted the above-described plasma generation electrode comprising a columnar electrode portion connected to a gas introduction tube and a high-frequency power source disposed around the gas introduction tube. The inventors have found that the object can be achieved and have completed the present invention.
That is, the present invention employs the following configurations 1 to 14.
1. A solution plasma reaction apparatus characterized in that a plasma generation electrode comprising a columnar electrode portion connected to a gas introduction pipe and a high-frequency power source arranged around the gas introduction pipe is provided in the solution reaction tank.
2. 2. The solution plasma reaction apparatus according to 1, wherein a cooling medium introduction part is provided at a central part of the plasma generating electrode.
3. 3. The solution plasma reactor according to 1 or 2, wherein the plasma generating electrode is provided so as to be movable in a vertical direction of the apparatus.
4). 4. The solution plasma reaction apparatus according to any one of 1 to 3, wherein another energy generation source is provided in the solution reaction tank.
5. 5. The solution plasma reaction apparatus according to 4, wherein the other energy generation source is an ultrasonic generation source.
Production of nanomaterials characterized by introducing gas plasma from a gas introduction tube into a reaction solution in which a raw material compound is dissolved or dispersed in a solvent in the solution plasma reactor described in any one of 6.1 to 5 Method.
7). The reaction solution is a reaction solution in which at least one compound selected from an organometallic complex, a metal alkoxide, and a metal salt is dissolved or dispersed in a solvent selected from water, oil, and alcohol. The manufacturing method of nanomaterial as described in any one of.
8). The nano gas according to 6 or 7, wherein the gas supplied from the gas supply pipe is at least one gas selected from water vapor, hydrogen, ammonia, helium, argon, nitrogen, oxygen, and hydrocarbon. Material manufacturing method.
9. The method for producing a nanomaterial according to any one of 6 to 8, wherein a plasma of gas is introduced into the reaction liquid in a state where the plasma generating electrode of the solution plasma reactor is immersed in the reaction liquid.
10. The method for producing a nanomaterial according to any one of 6 to 8, wherein a plasma of gas is introduced into the reaction liquid in a state where the plasma generating electrode of the solution plasma reaction apparatus is spaced upward from the liquid surface of the reaction liquid.
11. The method for producing a nanomaterial according to any one of 6 to 10, wherein the reaction solution is irradiated with other energy together with plasma.
12 12. The method for producing a nanomaterial according to 11, wherein the other energy is an ultrasonic wave.
13. The nanomaterial production method according to any one of 6 to 12, wherein the nanomaterial is fine particles having an average particle diameter of 1 nm to 10 µm.
14 The method for producing a nanomaterial according to any one of claims 6 to 12, wherein a film composed of fine particles having an average particle diameter of 1 nm to 10 µm is formed on the surface of a substrate disposed in the reaction solution.

According to the present invention, the following excellent effects can be obtained.
(1) In the apparatus of the present invention, a plasma having a high energy density is generated by using a high-frequency power source and a plasma generating electrode having a unique electrode structure, and this is introduced into a reaction solution to generate a solution plasma. It can be generated efficiently. At that time, by moving the position of the plasma generating electrode in the vertical direction, plasma having high energy can be introduced directly or separated into the reaction solution.
In addition, by providing the cooling medium introduction portion at the center of the electrode, damage due to heating of the electrode can be prevented. Furthermore, the configuration of the apparatus is simple and contributes to cost reduction, and the degree of freedom of the apparatus is increased, and the combined use with other energy irradiation sources (laser, external heating, ultrasonic wave, microwave, etc.) becomes easy.
(2) In the production method of the present invention, the reaction is completed by discharge, electromagnetic waves, heat, radicals, ultraviolet rays, etc. supplied from plasma, so that a pH adjusting agent, oxidizing agent, reducing agent required in a normal solution method is used. Etc. are unnecessary. For this reason, it becomes easy to process the waste liquid and it is a clean method.
In addition, it does not require a vacuum device, which is essential for ordinary vapor phase processes, and is not restricted by heating temperature or severe material selectivity conditions. It is possible to produce a material.
In addition, since the process is in solution, for example, in water, the temperature is essentially 100 ° C. or lower, so it is possible to select a substrate having a wide range of materials and shapes for use in film formation. Therefore, it can be applied not only to metal materials, but also to the production of engineering plastics, ceramic dielectric materials or piezoelectric materials, semiconductor materials, catalysts and the like.
As described above, the present invention enables preparation of metals, alloys or inorganic compounds composed of single nano-level crystal particles at a low cost by a simple process, and can be used in various industries from the electrical and electronic fields to the agricultural field. It can be widely applied to the world, medical field or various living environments.

Next, preferred embodiments of the present invention will be described with reference to the drawings, but the following specific examples do not limit the present invention.
1 and 2 are schematic cross-sectional views showing an example of the solution plasma reaction apparatus of the present invention. This reaction apparatus comprises a solution reaction tank 1 and a plasma generating electrode 2 disposed in the reaction tank 1, and the plasma generating electrode 2 is disposed around a gas introduction pipe 3 disposed in the center and the periphery thereof. A cylindrical electrode portion 4 is used. Since the plasma generating electrode 2 is heated to a high temperature by plasma generation, a cooling medium introducing unit 5 is installed at the center of the electrode unit 4 and can be cooled by air cooling or water cooling. In addition, a high frequency input terminal 6 for applying a high frequency from a high frequency power source (not shown) is provided in the electrode portion 4 so as to reach the cavity 9 at the center of the electrode portion 4 from the outside of the electrode portion 4.
An ultrasonic generator 7 is installed in the reaction tank 1 containing the reaction liquid 8 as another energy generation source for irradiation with plasma. The ultrasonic generator 7 can be omitted.

The plasma generating electrode 2 has a state in which the lower end portion of the electrode 2 is immersed in the reaction solution 8 as seen in FIG. 1 and the lower end portion of the electrode 2 is the liquid level of the reaction solution 8 as seen in FIG. It is configured to be movable in the vertical direction by a driving device (not shown) between the state and the state separated from the state.
In the state of FIG. 1, when a high frequency is applied from the high frequency input terminal 6 to the plasma generating electrode 2 while introducing the gas from the gas introduction tube 3, the electric field introduced from the high frequency input terminal 6 is introduced from the high frequency input terminal 6. This is converted into plasma, and this plasma is introduced into the reaction solution 8 in the reaction tank 1, and a part of the reaction solution is directly converted into plasma to form a solution plasma. This is called direct solution plasma. In direct solution plasma, the effects of discharge, radicals and heat can be directly and effectively transmitted to the reaction solution.

  On the other hand, when a high frequency is applied to the plasma generating electrode 2 in the state of FIG. 2, the reaction solution 8 is not directly converted into plasma at the input high frequency, but is indirectly converted into plasma through plasma by the introduced gas. This is called remote solution plasma. At this time, the distance between the lower end portion of the plasma generating electrode 2 and the reaction liquid surface is usually about 0.1 mm to 5 cm, preferably about 0.1 mm to 1 cm. In the remote solution plasma, the purity of the reaction solution can be maintained because it does not touch the electrode or the jig.

Moreover, the length L to the lower end part of the high frequency input terminal 6 and the electrode 2 is called a gap length (refer FIG. 2). The gap length L can be appropriately selected within a range of about 1 mm to about 10 cm, but is usually preferably about 1 cm to 5 cm.
When the gap length L exceeds 10 cm, the plasma does not efficiently propagate to the solution. On the other hand, when L is 1 mm or less, the high-frequency leakage electric field is rapidly increased, so that an electromagnetic wave shield is required in the periphery, which causes a practical problem.

The material and dimensions of each member constituting the plasma generating electrode 2 can be arbitrarily selected using commonly used materials such as metal and ceramics. For example, metals having good thermal conductivity such as aluminum and brass are preferably used as the electrode portion 4, and metals having high rigidity such as stainless steel can be used as the high frequency input terminal 6. And as the gas introduction tube 3, heat resistant ceramics, such as quartz and an alumina, are used suitably, and it is preferable that the diameter is normally about 100 micrometers-50 cm.
Further, the input high frequency has an optimal high frequency output and frequency in order to efficiently convert the reaction liquid into plasma. These are selected according to the diameter of the gas introduction tube 3, the type and flow rate of the gas to be introduced, and the type and amount of the solvent, and the output is about 1 W to 10 kW, preferably about 100 W to 6 kW, and its frequency. Is about 1 kHz to 100 GHz, preferably about 20 MHz to 10 GHz. The electric field density of the plasma generating electrode is preferably 1 × 10 ⁵ V / m or more, and more preferably about 1 × 10 ⁷ to 1 × 10 ⁹ V / m.

Next, a method for producing a nanomaterial using the solution plasma production apparatus of the present invention will be described.
As a preferable reaction solution used as a raw material of the nanomaterial, at least one compound containing metal selected from various organometallic complexes, metal alkoxides, metal salts, and the like, water, oil (for example, kerosene, benzene, It is possible to use those dissolved or dispersed in a solvent selected from hydrocarbon oils such as toluene) and alcohols (for example, aliphatic alcohols such as methanol and ethanol).
As such a compound, it is preferable to use at least one of an organometallic complex, a metal alkoxide, and a metal salt. It is appropriate to use those compounds whose decomposition temperature is usually in the range of about 20 ° C to 1000 ° C, particularly 20 to 350 ° C. Of these, compounds having a high vapor pressure and a low decomposition temperature can be more preferably used. In addition, when the solubility of these compounds is low, the solution is stirred during the treatment in order to enhance dispersibility.

The organometallic complex is not limited, but β diketones are particularly preferred. Among them, acetylacetonato ligand (acac), dipivaloylmethanato ligand (DPM), diisobutylmethanato ligand (DIBM), 2,2,6,6-tetramethyl-3,5-octane A complex having at least one kind of ligand such as diato ligand (TMOD) and 6-ethyl-2,2-dimethyl-3,5-octane dionato ligand (EDMOD) can be suitably used. . More specifically, Pd (acac) ₂ , Pt (acac) ₂ , Ni (acac) ₂ , Fe (acac) ₂ , Sn (acac) ₂ , In (acac) ₂ , Cu (acac) ₂ , Mg ( _{DPM) 2, La (DPM)} 3, Zr (DPM) 4, Ti (DPM) 2 (O-iso-C 3 H 7) 2 and the like.

Examples of the metal alkoxide include Si (OC ₂ H ₅ ) ₅ , Sb (OCH ₂ O ₅ ) ₃ , Ti (OC ₃ H ₇ ) ₄ , Zr (O-iso-C ₃ H ₇ ) ₄ , Al (O— iso-C ₃ H ₇ ) _{3 and the} like.
As the metal salt, metal halides such as chlorides and bromides can be preferably used. More specifically, iron chloride, platinum chloride, nickel chloride, HAuCl ₄ , K ₂ PtCl ₄ , Na ₂ PdCl _{4 and the} like can be mentioned.
Among these, it is preferable to use an organometallic complex in that no residue remains in the product.

The type of metal in the compound is not particularly limited, and can be appropriately selected according to catalyst characteristics, light emission characteristics, and other various desired performances. For example, gold, silver, copper, platinum, palladium, nickel, iron, aluminum, magnesium and the like are exemplified. These can be used alone or in combination of two or more. When using 2 or more types, it is also possible to form the nanoparticle or film which consists of an alloy or an intermetallic compound. In this case, two or more second-phase supply sources that differ only in metal species may be used, or two or more second-phase supply sources that differ in both metal species and organic sites may be used.
The purity of the compound to be used is not particularly limited, but a compound having a purity of 97% or more is preferably used. The concentration of these compounds in the reaction solution can be appropriately selected, but is usually about 0.01 to 40% by weight, preferably about 0.1 to 20% by weight.

  In order to produce a nanomaterial from a reaction solution containing these compounds, first, the reaction solution 8 is accommodated in the solution reaction tank 1 of the solution plasma reaction apparatus of the present invention. Next, at least one gas selected from water vapor, hydrogen, ammonia, helium, argon, nitrogen, oxygen, and hydrocarbon is supplied from the gas introduction pipe 3 at a rate of about 20 mL / min to 50 L / min, preferably 100 mL / min to 5 L. / Minute, and a high frequency is applied from the high frequency input terminal 6 to generate plasma, which is introduced into the solution reaction tank 1 to form solution plasma.

By this solution plasma, the metal raw material in the reaction solution is decomposed, reduced or heated to aggregate, and particles having a particle diameter of about 1 nm to 10 μm are formed. The structure of such nanoparticles can be easily confirmed with a transmission electron microscope or the like.
In order to form a film made of nanoparticles, a film made of nanoparticles is formed on the surface of the substrate by placing a substrate such as a plate-like body in the reaction solution and generating solution plasma. it can.

  According to the present invention, when the reaction solution is exposed to direct solution plasma or remote solution plasma, the raw material compound is simply decomposed by the effects of discharge generated by the plasma, active species such as hydrogen radicals, heat, and ultraviolet rays. In addition to reduction deposition, the nanoparticle or coating containing a metal, alloy or inorganic compound is formed by reacting with the solution.

  In the present invention, since direct solution plasma or remote solution plasma is formed in the reaction solution, the degree of freedom in the reaction is increased. In particular, in the remote solution plasma, the degree of freedom of the configuration of the reaction liquid portion is high, and other energy such as ultrasonic waves can be simultaneously applied as seen in FIGS. As this energy type, any of heat, light (including infrared rays, ultraviolet rays, and lasers), ultrasonic waves, electromagnetic fields (including microwaves and terahertz waves) can be used. In particular, irradiation with ultrasonic waves is preferable because the dispersibility of the obtained particles is improved. As the frequency of this ultrasonic wave, a frequency of 10 kHz to 1 MHz can be used, but 20 to 100 kHz is preferable for the purpose of dispersion. In addition, examples of the ultrasonic wave generation method at this time include a horn type and a Langevin vibrator type, and may be appropriately used in accordance with the shape of the solution tank.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these specific examples.
(Example 1)
The solution plasma reactor shown in FIG. 2 was used, and a high frequency power source consisting of 2.45 GHz and a maximum output of 6 kW was connected to the plasma generating electrode 2. At that time, the gap length L was 3 cm, and the distance between the lower end of the electrode 2 and the liquid surface was fixed to 1 mm. Further, helium (purity 99.99%) was used as a plasma generating gas. As the reaction solution 8, water (50 mL) is used as a solvent, tetrachloroauric acid (HAuCl ₄ ) is weighed to be 0.5 mM / L as a metal supply source, mixed with water, and sufficiently stirred. Thus, an aqueous solution was prepared and set in the solution reaction tank 1.
A high frequency was applied to the reaction solution at an output of 500 W at a helium flow rate of 1 L / min, and the resulting helium plasma was introduced into the reaction solution 8 and held for 10 minutes.

The obtained solution is dropped on the collodion film, and the result of observation with a transmission electron microscope after drying is shown in FIG. As shown in FIG. 3, it was confirmed that a nanomaterial composed of gold particles having an average particle diameter of 7 nm was obtained. It was also found that the particle size slightly increased by increasing the concentration of tetrachloroauric acid (HAuCl ₄ ).

(Example 2)
The solution plasma reactor shown in FIG. 2 was used, and a high frequency power source consisting of 2.45 GHz and a maximum output of 6 kW was connected to the plasma generating electrode 2. At that time, the gap length L was 3 cm, and the distance between the lower end of the electrode 2 and the liquid surface was fixed to 1 mm. In this example, a Langevin vibrator type ultrasonic generator 7 having a frequency of 40 kHz and an output of 90 W was installed in the reaction tank 1 to perform ultrasonic irradiation.
Further, helium (purity 99.99%) was used as a plasma generating gas. As the reaction solution 8, water (50 mL) is used as a solvent, and tetrachloroauric acid is weighed to be 0.5 mM / L as a metal supply source, and then mixed with water as a solvent and sufficiently stirred. Thus, an aqueous solution was prepared and set in the solution reaction tank 1. A high frequency was applied to the reaction solution 8 at an output of 500 W at a helium flow rate of 1 L / min, and the resulting helium plasma was introduced into the reaction solution and held for 10 minutes while simultaneously irradiating ultrasonic waves. The obtained solution is dropped on the collodion membrane, and the result of observation with a transmission electron microscope after drying is shown in FIG. As shown in FIG. 4, it was confirmed that a nanomaterial composed of gold particles having an average particle diameter of 7 nm was obtained. In this example, unlike Example 1 in which the particles are agglomerated, it was confirmed that substantially monodispersed particles were obtained.

(Example 3)
In Example 2, a solution plasma reaction was performed in the same manner as in Example 2 except that potassium tetrachloroplatinate (II) (K ₂ PtCl ₄ ) was used as the metal supply source. The obtained solution was dropped on the collodion film, and the result of observation with a transmission electron microscope after drying was shown in FIG. As shown in FIG. 5, it was confirmed that a nanomaterial composed of platinum particles having an average particle diameter of 6 nm was obtained. Also in this example, as in Example 2, it was confirmed that substantially monodispersed particles were obtained.

Even when the nanomaterials obtained in Examples 2 and 3 were observed with a transmission electron microscope having a resolution of 1 nm or less, impurities other than gold or platinum particles were not confirmed, and ultrasonic waves were used together. It was confirmed that the method is a method of producing a very clean nanomaterial.
As described above, by using the solution plasma generator having the novel electrode structure of the present invention, there is no need for a highly restrictive means such as a vacuum system, and there is a risk of contamination into the solution and material selection. Without being restricted, nanomaterials having a fine form can be efficiently produced at low cost by a simple process.

It is a schematic diagram which shows one use condition of the solution plasma reaction apparatus of this invention. It is a schematic diagram which shows the other use condition of the solution plasma reactor of this invention. 2 is a transmission electron microscope image of gold particles obtained in Example 1. FIG. 3 is a transmission electron microscope image of gold particles obtained in Example 2. FIG. 3 is a transmission electron microscope image of platinum particles obtained in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solution reaction tank 2 Plasma generating electrode 3 Gas introducing pipe 4 Electrode part 5 Cooling medium introducing | transducing part 6 High frequency input terminal 7 Ultrasonic generator 8 Reaction liquid 9 Cavity

Claims (14)

  A solution plasma reaction apparatus characterized in that a plasma generation electrode comprising a columnar electrode portion connected to a gas introduction pipe and a high-frequency power source arranged around the gas introduction pipe is provided in the solution reaction tank.   The solution plasma reaction apparatus according to claim 1, wherein a cooling medium introduction part is provided at a central part of the plasma generating electrode.   3. The solution plasma reactor according to claim 1, wherein the plasma generating electrode is provided so as to be movable in a vertical direction of the apparatus.   The solution plasma reaction apparatus according to claim 1, further comprising another energy generation source in the solution reaction tank.   5. The solution plasma reactor according to claim 4, wherein the other energy generation source is an ultrasonic generation source.   Production of a nanomaterial characterized by introducing gas plasma from a gas introduction tube into a reaction solution in which a raw material compound is dissolved or dispersed in a solvent in the solution plasma reactor according to any one of claims 1 to 5. Method.   The reaction solution is a reaction solution in which at least one compound selected from an organometallic complex, a metal alkoxide, and a metal salt is dissolved or dispersed in a solvent selected from water, oil, and alcohol. Item 7. A method for producing a nanomaterial according to Item 6.   The gas supplied from the gas supply pipe is at least one gas selected from water vapor, hydrogen, ammonia, helium, argon, nitrogen, oxygen, and hydrocarbons. Nanomaterial manufacturing method.   The method for producing a nanomaterial according to any one of claims 6 to 8, wherein a plasma of gas is introduced into the reaction liquid in a state where the plasma generating electrode of the solution plasma reaction apparatus is immersed in the reaction liquid.   9. The nanomaterial production according to claim 6, wherein a plasma of gas is introduced into the reaction liquid in a state where the plasma generating electrode of the solution plasma reaction apparatus is spaced upward from the liquid surface of the reaction liquid. Method.   The method for producing a nanomaterial according to claim 6, wherein the reaction liquid is irradiated with other energy together with plasma.   The nanomaterial manufacturing method according to claim 11, wherein the other energy is ultrasonic.   The method for producing a nanomaterial according to any one of claims 6 to 12, wherein the nanomaterial is a fine particle having an average particle diameter of 1 nm to 10 µm.   The method for producing a nanomaterial according to any one of claims 6 to 12, wherein a film composed of fine particles having an average particle diameter of 1 nm to 10 µm is formed on the surface of a substrate disposed in the reaction solution.

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