JP2019127409A - Metal oxide porous body and method for producing the same - Google Patents

Abstract

To provide a metal oxide porous body having a meso-porous structure excellent in structural regularity.SOLUTION: A metal oxide porous body has a skeleton part and a mesopore 11 having a two-dimensional hexagonal structure, wherein the skeleton part contains a manganese- and a tantalum-containing amorphous oxide, and has a BET specific surface area of 100 m/g or more. A production method includes: preparing an ethanol solution obtained by dissolving a neutral block copolymer, water, manganese chloride, and tantalum chloride in ethanol; drying the ethanol solution; and calcining the dried product at 450°C or higher and 600°C or lower under an oxygen-containing atmosphere.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal oxide porous body and a method for producing a metal oxide porous body.

  A material having a mesoporous structure is expected as a material having various physicochemical functions such as a highly selective catalyst because of the uniformity of its pores. In addition, since the nanostructured pores of the porous material exhibit a quantum effect, the mesoporous material has attracted attention in various fields from such a viewpoint.

  There is mesoporous oxide as a material of mesoporous structure, but mesoporous oxide has been developed focusing on silica. The high surface area of mesoporous silica is effective for the adsorption of various gases, liquids and toxic heavy metals. When using a mesoporous material such as mesoporous silica as an adsorbent, for example, removal of contaminants from water, adsorption of gases such as carbon dioxide, hydrogen, oxygen, methane, and sulfur dioxide, separation of biological materials and pharmaceuticals, etc. It's being used. However, mesoporous silica has no function such as catalytic action because the substance is silica.

  On the other hand, many transition metal oxide powders have various catalytic properties. The transition metal oxide has a Lewis acid point, a Lewis base point, a Bronsted acid point, and a Bronsted base point, and is an active point that exhibits various catalytic functions. However, much of its performance is highly dependent on the surface area of the powder. In general, the larger the surface area of the oxide, the more these active sites, and the higher the catalytic function per unit mass, the higher the value.

  Therefore, studies have also been made on non-silica based mesoporous oxides.

  For example, in Patent Document 1, at least a metal oxide to be doped is added to an organic solvent solution containing a template agent, and the added solution is stirred to uniformly disperse the metal oxide. Including a transition metal compound that forms a mesoporous structure oxide by a sol-gel method or a transition metal compound that forms a mesoporous structure oxide and an acid, and an acid condition for solubilizing the doped metal oxide. A method of synthesizing a metal-doped mesoporous transition metal oxide has been proposed in which the metal oxide-derived metal is caused to exist at atomic level uniformity by a sol-gel method. Patent Document 1 discloses an example in which Fe-doped mesoporous niobium oxide is prepared.

Patent Document 2 proposes a mesoporous metal oxide composite optical waveguide sensor characterized in that the surface of a light amplification layer provided on the surface layer of an optical waveguide is covered with a mesoporous metal oxide thin film. Patent Document 2 discloses an example in which mesoporous metal oxide WO ₃ is prepared.

JP 2004-250277 A JP, 2006-098284, A

  As proposed in Patent Documents 1 and 2 and the like, various studies have been made on non-silica materials having a mesoporous structure containing a transition metal oxide.

  However, in recent years, it has been studied to use a metal oxide porous body having a mesoporous structure not only for a catalyst but also for various applications such as a nanodevice. And the metal oxide porous body excellent in structural regularity was calculated | required.

  In view of the problems of the prior art described above, an object of the present invention is to provide a metal oxide porous body having a mesoporous structure excellent in structural regularity.

In one aspect of the present invention to solve the above problems,
Having a skeleton and mesopores of a two-dimensional hexagonal structure,
The skeleton contains an amorphous oxide containing manganese and tantalum,
Provided is a metal oxide porous body having a BET specific surface area of 100 m ² / g or more.

  According to one aspect of the present invention, it is possible to provide a metal oxide porous body having a mesoporous structure excellent in structural regularity.

Explanatory drawing of a two-dimensional hexagonal structure. TEM observation image of the metal oxide porous body obtained in Example 2. TEM observation image of the sample obtained in Comparative Example 1. TEM observation image of the sample obtained in Comparative Example 2.

Hereinafter, although the form for carrying out the present invention is explained with reference to drawings, the present invention is not limited to the following embodiment, and does not deviate from the scope of the present invention. Various modifications and substitutions may be made.
[Metal oxide porous body]
Hereinafter, the metal oxide porous body of the present embodiment will be described.

The metal oxide porous body of the present embodiment has a skeleton and mesopores of a two-dimensional hexagonal structure, and the skeleton contains an amorphous oxide containing manganese and tantalum, and has a BET specific surface area. Can be 100 m ² / g or more.

  The metal oxide porous body of the present embodiment can have a skeleton and mesopores of a two-dimensional hexagonal structure.

  The skeleton of the metal oxide porous body of the present embodiment can contain an amorphous oxide containing manganese and tantalum. Note that the skeleton portion of the metal oxide porous body of the present embodiment can also be composed of an amorphous oxide containing manganese and tantalum. According to the study of the inventors of the present invention, it is possible to obtain a two-dimensional porous metal oxide body having a skeleton containing an amorphous oxide containing manganese and tantalum, which has not been studied before. It becomes easy to form mesopores of hexagonal structure. For this reason, it can be set as the metal oxide porous body which has the mesoporous structure excellent in structural regularity.

  In addition, about the metal oxide porous body of this embodiment, for example, when the electron beam diffraction using a transmission electron microscope is measured, the oxide contained in the skeleton portion shows a halo pattern, so that manganese and tantalum are obtained. It can be confirmed that the oxide contained is amorphous.

  The two-dimensional hexagonal structure refers to a structure in which mesopores are arranged in a hexagonal shape in a cross section perpendicular to the longitudinal direction of the mesopores. FIG. 1 is a diagram schematically showing a cross section perpendicular to the longitudinal direction of the meso hole 11. The two-dimensional hexagonal structure means a structure in which mesopores 11 are regularly arranged in a hexagonal shape, that is, a hexagonal shape indicated by a dotted line 12 as shown in FIG. By having a two-dimensional hexagonal structure, a metal oxide porous body having a mesoporous structure having a large specific surface area and excellent structure regularity can be obtained.

  In addition, it is possible to perform low-angle X-ray diffraction measurement on the metal oxide porous body, and to determine whether it has a two-dimensional hexagonal structure based on the presence or absence of a diffraction peak resulting from the skeletal structure of the ordered mesopores. In addition, it can be determined whether the mesopores of the metal oxide porous body have a two-dimensional hexagonal structure by observation using a transmission electron microscope.

And it is preferable that the metal oxide porous body of this embodiment has a BET specific surface area of 100 m ² / g or more. This is because when the BET specific surface area is 100 m ² / g or more, particularly excellent characteristics can be exhibited in various uses such as a catalyst and a nanodevice.

Since the BET specific surface area is preferably as large as possible, the upper limit thereof is not particularly limited. However, for example, 200 m ² / g or less is preferable from the viewpoint of exhibiting the mechanical strength of the metal oxide porous body.

  The BET specific surface area can be calculated from the isotherm, for example, by performing adsorption and desorption isotherm measurement by a nitrogen adsorption method. In addition, it can also confirm that the metal oxide porous body used for the measurement has a mesopore by having the shape which the adsorption / desorption isotherm by a nitrogen adsorption method belongs to the IV type of IUPAC.

According to the metal oxide porous body of the present embodiment described above, a metal oxide porous body having a mesoporous structure excellent in structural regularity can be obtained.
[Method for producing porous metal oxide body]
Next, a method of manufacturing the metal oxide porous body of the present embodiment will be described. In addition, the metal oxide porous body described above can be manufactured by the method for manufacturing a metal oxide porous body of the present embodiment. For this reason, explanation is omitted about a part of already explained matter.

  The manufacturing method of the metal oxide porous body of this embodiment can have the following processes.

An ethanol solution preparation step of preparing an ethanol solution in which a neutral block copolymer, water, manganese chloride, and tantalum chloride are dissolved in ethanol.
A drying step of obtaining a dried product by drying the solvent and water in the ethanol solution.
A firing step of firing the dried product at a temperature of 450 ° C. or more and 600 ° C. or less in an atmosphere containing oxygen.
And it is preferable that each component in the ethanol solution prepared at an ethanol solution preparation process satisfies the following ratio.

The neutral block copolymer / ethanol, which is a mass ratio of the neutral block copolymer to ethanol, is 0.09 or more and 0.11 or less.
Water / ethanol, which is a mass ratio of water to ethanol, is 0.00 or more and 0.015 or less.
Manganese chloride / ethanol, which is a mass ratio of manganese chloride to ethanol, is 0.020 or more and 0.030 or less.
Tantalum chloride / ethanol, which is a mass ratio of tantalum chloride to ethanol, is 0.130 or more and 0.190 or less.

  In the method for producing a metal oxide porous body of the present embodiment, a metal oxide porous body having a mesoporous structure, specifically, a metal oxide having a skeleton and a mesopore of a two-dimensional hexagonal structure by a sol-gel method. Porous body can be manufactured.

  Conventionally, sol-gel methods have been used for the synthesis of mesoporous structure transition metal oxides and the like. As basic materials used in the synthesis of conventional mesoporous structure transition metal oxides, for example, surfactants that are self-assembled in the process of gelation and serve as templates for mesoporous structure transition metal oxides, especially neutral Template agents such as block copolymers are included. Moreover, the organic solvent which melt | dissolves a template agent, especially alcohol, and the salt of the transition metal which forms a mesoporous structure transition metal oxide, for example, a chloride, an oxide, nitrate, an alkoxide, etc. are mentioned.

  However, it has been difficult to produce a metal oxide porous body having a mesoporous structure excellent in structural regularity by the conventional method for producing a mesoporous structured transition metal oxide.

  Therefore, the inventors of the present invention conducted intensive studies and found a method for producing a metal oxide porous body capable of producing a metal oxide porous body having a mesoporous structure excellent in structural regularity, and completed the present invention.

  Hereinafter, each process is explained in full detail, explaining the reaction mechanism of the manufacturing method of the metal oxide porous body of this embodiment.

  In the ethanol solution preparation step, the components to be the raw material of the metal oxide porous body can be mixed to prepare an ethanol solution. Specifically, in the ethanol solution preparation step, the neutral block copolymer, water, manganese chloride and tantalum chloride can be mixed with ethanol to prepare an ethanol solution. Since water may be contained in ethanol or metal salts, water can be added when preparing an ethanol solution when a sufficient amount of water can be supplied by the water contained in ethanol. You can not.

  When the ethanol solution prepared in the ethanol solution preparation step is dried in the drying step and the solvent and water are dried, the neutral block copolymer forms micelles and is arranged in a rod shape. Rod-like micelles are attracted by intermolecular force and regularly arranged in a two-dimensional hexagonal structure.

  Then, according to the study of the inventors of the present invention, by using tantalum chloride as a tantalum source, micelles arranged in a rod shape as described above can be regularly arranged in a two-dimensional hexagonal structure. For this reason, according to the method for producing a metal oxide porous body of the present embodiment, a metal oxide porous body having a mesoporous structure excellent in structural regularity can be produced with good reproducibility.

  Further, when manganese chloride and tantalum chloride contained in the ethanol solution are dissolved in the ethanol solution, hydrochloric acid is generated, and one of the chloride ions is substituted with ethoxide to become a metal compound monomer. In the manufacturing method of the metal oxide porous body of this embodiment, the reason why manganese chloride is used as the manganese source is to obtain the metal compound monomer in this way. During the aging in the ethanol solution preparation step and the drying step described later, the metal compound monomer is hydrolyzed with a small amount of water, and the hydroxyl groups generated in the monomer by hydrolysis are dehydrated and condensed between the monomers. The crosslinking reaction occurs. An inorganic phase is formed by repeating the above hydrolysis and dehydration condensation.

  Thus, the formation of the organic phase micelles in the ethanol solution, self-assembly, ie, the formation of the arrangement of the two-dimensional hexagonal structure, and the timing of the formation of the inorganic phase coincide with each other to form the matrix of the inorganic phase. It will be in the state in which the organic phase self-assembled is contained.

  Then, a dried product maintaining the above-described form is obtained by a drying process described later, and further, an organic phase is burned off by performing a baking process described later, and the inorganic phase maintains its shape and is amorphous (amorphous). ) Become an oxide. For this reason, it can be set as the metal oxide porous body which has the mesoporous structure excellent in structural regularity.

  According to the study of the inventors of the present invention, it is determined that each component in the ethanol solution is contained in a predetermined ratio with respect to ethanol, so that the metal oxide porous material having a mesoporous structure with excellent structure regularity. It is important to gain the body.

  Specifically, as described above, the neutral ratio of the neutral block copolymer to ethanol, i.e., the value obtained by dividing the mass ratio of the neutral block copolymer added to the ethanol solution by the mass ratio of ethanol. The block copolymer / ethanol is preferably 0.09 or more and 0.11 or less.

  This is because when the neutral block copolymer / ethanol is 0.09 or more, the ratio of the organic phase to the inorganic phase can be sufficiently increased, and the intermolecular force between the adjacent rod-like micelles can be increased. This is because they can work sufficiently and self-arrange in a two-dimensional hexagonal structure. When the neutral block copolymer / ethanol is less than 0.09, a mesopore is formed but a metal oxide porous body having no two-dimensional hexagonal structure may be formed, which is not preferable.

  Further, by setting the mass ratio of neutral block copolymer / ethanol to 0.11 or less, a sufficient amount of inorganic phase can be supplied between rod-like micelles self-aligned in a two-dimensional hexagonal structure, A metal oxide porous body having a desired skeletal structure can be obtained.

  Moreover, it is preferable that water / ethanol which is a value obtained by dividing the mass ratio of water to ethanol, that is, the mass ratio of water added to the ethanol solution by the mass ratio of ethanol is 0.00 or more and 0.015 or less.

  This is because by setting water / ethanol to 0.015 or less, it is possible to suppress the formation of hydroxide for one of the chloride ions, and more reliably substitute with ethoxide to obtain a metal compound monomer. It is. For this reason, a sufficient amount of inorganic phase can be supplied between rod-like micelles to make a metal oxide porous body having a mesoporous structure. In addition, when water / ethanol exceeds 0.015, a mesopore may not be formed but only the aggregate | assembly of a normal nanoparticle may be formed, and it is unpreferable.

  In addition, water is not restricted to the water added when preparing an ethanol solution, For example, it is preferable that water / ethanol satisfy | fills the said range including the water contained in ethanol and the water contained in a metal salt.

  The mass ratio of manganese chloride to ethanol, that is, the value obtained by dividing the mass ratio of manganese chloride added to the ethanol solution by the mass ratio of ethanol, is preferably 0.020 or more and 0.030 or less. In addition, the mass ratio of tantalum chloride to ethanol, that is, the value obtained by dividing the mass ratio of tantalum chloride added to the ethanol solution by the mass ratio of ethanol is preferably 0.130 or more and 0.190 or less. .

  This is because manganese chloride / ethanol is 0.020 or more and tantalum chloride / ethanol is 0.130 or more, so that a sufficient amount of inorganic phase can be supplied between the arranged rod-like micelles. For this reason, after a baking process, a mesopore can not be formed without maintaining a framework | skeletal structure, and it can prevent more reliably becoming an aggregate | assembly of a normal nanoparticle.

  By setting the manganese chloride / ethanol to 0.030 or less and the tantalum chloride / ethanol to 0.190 or less, the ratio of the inorganic phase to the organic phase is prevented from becoming excessively large, and the distance between adjacent rod-like micelles This is because the intermolecular force works sufficiently and can self-arrange in a two-dimensional hexagonal structure. Therefore, it is possible to reliably prevent the formation of a metal oxide porous body in which mesopores are formed but a two-dimensional hexagonal structure can not be obtained after the firing step.

The neutral block copolymer is not particularly limited, but is a polypropylene oxide (PO) chain-polyethylene oxide (EO) chain-polypropylene oxide (PO) chain triblock copolymer ((PO) _x (EO) _y (PO) _x ) Is preferable.

The polypropylene oxide (PO) chain is represented by (CH ₂ CH (CH ₃ ) O) _x and is also referred to as “PO”. The polyethylene oxide (EO) chain is represented by (CH ₂ CH ₂ O) _y and is also referred to as “EO”.

  Although x and y in the above formula are not particularly limited, x is preferably 5 or more and 110 or less, and more preferably 15 or more and 20 or less. Moreover, y is preferably 15 or more and 70 or less, and more preferably 50 or more and 70 or less.

Examples of such triblock copolymer include (EO) ₅ (PO) ₇₀ (EO) ₅ , (EO) ₁₃ (PO) ₃₀ (EO) ₁₃ , (EO) ₂₀ (PO) ₃₀ (EO) ₂₀ , (EO) ₂₆ (PO) ₃₉ (EO) ₂₆ , (EO) ₁₇ (PO) ₅₆ (EO) ₁₇ , (EO) ₁₇ (PO) ₅₈ (EO) ₁₇ , (EO) ₂₀ (PO) ₇₀ (EO) ₂₀ , (EO) ₈₀ (PO) ₃₀ (EO) _{80, and the} like. In particular, (EO) ₂₀ (PO) ₇₀ (EO) ₂₀ can be preferably used.

  And in the manufacturing method of the metal oxide porous body of this embodiment, a drying process and a baking process can be further implemented.

  In the drying step, the solvent and water in the ethanol solution can be dried to obtain a dried product. In addition, ethanol etc. are mentioned as a solvent.

  Although the drying conditions in this case are not particularly limited, it is preferable that the drying does not proceed rapidly from the viewpoint of enhancing the structural regularity of the obtained metal oxide porous body. For this reason, it is preferable to implement the drying in a drying process in the environment of 20 degreeC or more and 80 degrees C or less, for example. Moreover, it is preferable to arrange | position lid | covers, such as a wrap, in the opening part of the container which put the ethanol solution, and to open several holes in this cover part, and to adjust a drying rate.

  In the firing step, the dried product obtained in the drying step can be fired at 450 ° C. to 600 ° C. in an atmosphere containing oxygen, for example, in the air.

  According to the manufacturing method of the metal oxide porous body of the present embodiment described above, by using a predetermined ethanol solution, the metal oxide porous body having a mesoporous structure excellent in structural regularity can be stably reproduced with high reproducibility. Can be manufactured.

The present invention will be described with reference to specific examples, but the present invention is not limited to these examples.
(About evaluation method)
The following evaluation was performed about the sample produced by the following example and comparative example.
(1) Nitrogen adsorption / desorption isotherm shape, BET specific surface area For samples prepared in each example and comparative example, a nitrogen adsorption method using a specific surface area / pore distribution measuring device (Beckman Coulter Model: SA3100) The adsorption / desorption isotherm was measured by means of the above, and it was examined whether or not the isotherm had an IUPAC type IV shape as seen when it has a mesoporous structure. If it has the IUPAC form IV, it is described as "IUPAC form IV" in the "Form of nitrogen adsorption and desorption isotherm" column of Table 1, otherwise it is described as x ing. In addition, when it has the form of IUPAC type IV, the sample has mesopores.

Moreover, the specific surface area by BET method was estimated from the isotherm obtained at this time. Table 1 lists the evaluation results in the column “BET specific surface area”.
(2) Presence / absence of low-angle X-ray diffraction peak due to skeleton structure of regular arrangement of mesopores For samples prepared in each Example and Comparative Example, an X-ray diffractometer (Model: RINT2100, CuKα ray manufactured by Rigaku) was used. Then, low-angle X-ray diffraction measurement was performed, and the presence or absence of a diffraction peak due to the skeleton structure of the ordered arrangement of mesopores was examined. When such a diffraction peak is observed, the mesopores have a two-dimensional hexagonal structure. For this reason, in the sample in which the column of "presence or absence of the low angle X-ray diffraction peak due to the skeletal structure of the ordered array of mesopores" in Table 2 is "presence", Will be. The sample in which the column is “absent” can not confirm the diffraction peak due to the skeleton structure of the ordered array of mesopores, and does not have the mesopores arranged in the two-dimensional hexagonal structure.
(3) Presence / absence of mesopores having a two-dimensional hexagonal structure by TEM observation For the samples obtained in each of the examples and comparative examples, transmission electron microscope (TEM) (manufactured by JEOL Ltd., model: JEOL JEM2010) Observation of mesopore formation by. In Table 2, in the sample in which “presence or absence of mesopores having a two-dimensional hexagonal structure by TEM observation” is “presence”, it is observed that the mesopores have a two-dimensional hexagonal structure when observed by TEM. It means that it was confirmed. The sample in which the column is “absent” can not be confirmed to have a two-dimensional hexagonal structure when observed by TEM, and thus it does not have mesopores arranged in a two-dimensional hexagonal structure. .

Further, from the electron diffraction, all oxides showed a halo pattern, so it was confirmed that they had an amorphous structure.
Example 1
The production and evaluation of the metal oxide porous body were performed according to the following procedure.

In a Teflon (registered trademark) beaker, 10 g of ethanol (super-dehydrated, 99.5%) was weighed as a solvent. Next, the neutral block copolymer P123 (manufactured by Aldrich Co.) represented by HO (CH ₂ CH ₂ O) ₂₀ (CH ₂ CH (CH ₃ ) O) ₇₀ (CH ₂ CH ₂ O) ₂₀ H in the above ethanol ) 1 g was added and stirred with a magnetic stirrer to dissolve completely.

  Then, to a solution in which a neutral block copolymer was dissolved in ethanol, manganese chloride and tantalum chloride (manufactured by High Purity Chemical Co., Ltd.) were added and stirred to dissolve completely to prepare an ethanol solution (ethanol solution preparation Process).

  In addition, manganese chloride (II) anhydride (STREM CHEMICALS, INC) was used as manganese chloride.

  Neutral block copolymer in ethanol solution, water, manganese chloride, mass ratio of tantalum chloride to ethanol, specifically neutral block copolymer / ethanol, water / ethanol, manganese chloride / ethanol, tantalum chloride / ethanol Is shown in Table 1. The amount of water in calculating water / ethanol in Table 1 is derived from water in ethanol. In addition, the water in ethanol is calculated from purity, and is calculated as 0.5%.

  The prepared ethanol solution was transferred to a beaker with a diameter of 100 mm, covered with a wrap with 20 small holes evenly with a needle so that the solvent would volatilize appropriately, and placed in a constant temperature bath at 40 ° C. and dried for 1 week (dry Process).

  The dried product obtained in the drying step was peeled off from the petri dish, placed in a crucible and set in an electric furnace, and heated and calcined at 550 ° C. for 30 hours in the air to obtain an oxide (baking step).

  The evaluation described above was performed on this oxide. The results are shown in Table 2.

Further, the obtained metal oxide porous body was quantitatively analyzed by ICP (Inductively Coupled Plasma) emission spectroscopy using an ICP emission analyzer (model: ICPS-800 manufactured by Shimadzu Corporation). Manganese and tantalum were almost as prepared. It was confirmed that the composition ratio was reached.
[Examples 2 to 5]
In the same manner as in Example 1, except that in the ethanol solution preparation step, the mass ratio of each raw material was made to be the value shown in Table 1, a metal oxide porous body was prepared and the evaluation described above was performed. It was.

  In Example 3, manganese chloride (II) tetrahydrate (special grade, Wako Pure Chemical Industries, Ltd.) was used as manganese chloride instead of manganese chloride (II) anhydride. For this reason, the amount of water when calculating water / ethanol is calculated by adding water in ethanol and water derived from manganese (II) chloride tetrahydrate.

  The evaluation results are shown in Table 2.

Further, the obtained metal oxide porous body was quantitatively analyzed by ICP emission spectroscopy, and it was confirmed that the composition ratio of manganese and tantalum was almost as prepared.
[Comparative Examples 1 to 5]
In the same manner as in Example 1, except that in the ethanol solution preparation step, the mass ratio of each raw material was made to be the value shown in Table 1, a metal oxide porous body was prepared and the evaluation described above was performed. It was.

  In Comparative Example 3, manganese chloride (II) tetrahydrate (special grade, Wako Pure Chemical Industries, Ltd.) was used instead of manganese chloride (II) anhydride (STREM CHEMICALS, INC) as manganese chloride. Ion exchange water was added dropwise to prepare an ethanol solution. For this reason, the amount of water when calculating water / ethanol is calculated by adding the water in ethanol, the water derived from manganese (II) chloride tetrahydrate, and the ion-exchanged water dropped. Yes.

  The evaluation results are shown in Table 2.

  Further, the obtained metal oxide porous body was quantitatively analyzed by ICP emission spectroscopy, and it was confirmed that the composition ratio of manganese and tantalum was almost as prepared.

As shown in Table 2, Examples 1 to 5 have a skeleton part and a mesopore having a two-dimensional hexagonal structure, and the skeleton part is an amorphous oxide containing manganese and tantalum. It has been confirmed that a metal oxide porous body containing a BET specific surface area of 100 m ² / g or more can be obtained.

  This is because the components in the ethanol solution are mixed so as to have a predetermined mass ratio, and in the ethanol solution, micelles that are organic phases, self-organization, that is, the formation of a two-dimensional hexagonal structure array, It is considered that sufficient inorganic phase can be supplied between the organic phases. Then, a dried product maintaining the above-described form is obtained by the drying step, and further, the organic phase is burned out by carrying out the firing step, and the inorganic phase maintains its shape and becomes an amorphous (amorphous) oxide. Since it became, it is thought that it could be set as the metal oxide porous body which has the mesoporous structure excellent in structural regularity.

  Further, from the results of TEM observation, in Examples 1 to 5, mesopores having a two-dimensional hexagonal structure with pore diameters of about 3.9 nm to 4.5 nm and wall thicknesses of 3.3 nm to 3.8 nm are formed. I could confirm that it was done.

  The TEM photograph of Example 2 is shown in FIG. 2 as an example of a TEM photograph. As shown in FIG. 2, it was confirmed that a mesoporous metal oxide porous body excellent in structural regularity in which the mesopores 21 were arranged so as to have a two-dimensional hexagonal structure was obtained. In addition, although only the TEM image of Example 2 is shown here, it has been confirmed that the same structure is provided also in the other Example 1 and Examples 3 to 5.

  On the other hand, in Comparative Example 1, mesopores were formed but no two-dimensional hexagonal structure was observed. This is because the mass ratio of the metal chloride in the ethanol solution was large, and it is considered that the micelles of the surfactant were not regularly arranged due to the intermolecular force.

  The TEM observation image of the sample obtained in Comparative Example 1 is shown in FIG. As shown in FIG. 3, although mesopores were confirmed, structural regularity could not be confirmed.

  In Comparative Example 2, the nitrogen adsorption / desorption isotherm is not in the form of IUPAC type IV, and mesopores are not formed. This is considered to be due to the disappearance of the skeleton of the inorganic phase when the micelles are burned off at the time of firing since the mass proportion of metal chloride in the ethanol solution was small.

  The TEM observation image of the sample obtained in Comparative Example 2 is shown in FIG.

  The sample obtained in Comparative Example 3 had a small specific surface area and the nitrogen adsorption and desorption isotherm was not in the form of IUPAC type IV. This is thought to be because the amount of water in the ethanol solution was so large that the metal chloride was hydrolyzed too quickly and a hydroxide precipitate was produced.

  The sample obtained in Comparative Example 4 had an IUPAC type IV nitrogen adsorption / desorption isotherm, confirming the formation of mesopores. However, it was confirmed from the results of low angle X-ray diffraction and TEM observation that the mesopores were not arranged in a two-dimensional hexagonal structure. This is because the neutral block copolymer mass ratio in the ethanol solution was small, and the mass ratio of the metal chloride content was relatively large, so that the micelles of the surfactant were not ordered by intermolecular force. It can be considered that.

  In the sample obtained in Comparative Example 5, it was confirmed that the shape of the nitrogen adsorption / desorption isotherm was not IUPAC type IV and no mesopores were formed. This is because the mass proportion of the neutral block copolymer in the ethanol solution is too large, and the mass proportion of the metal chloride is relatively too small, and the skeleton of the inorganic phase disappears when the micelles are burned off at the time of firing It is thought that it is due to having been done.

11, 21 Mesopore

Claims (3)

Having a skeleton and mesopores of a two-dimensional hexagonal structure,
The skeleton contains an amorphous oxide containing manganese and tantalum,
A metal oxide porous body having a BET specific surface area of 100 m ² / g or more. Preparing an ethanol solution in which a neutral block copolymer, water, manganese chloride, and tantalum chloride are dissolved in ethanol;
A drying step of obtaining a dried product by drying the solvent and water in the ethanol solution;
And B. firing the dried product at a temperature of 450 ° C. or more and 600 ° C. or less in an atmosphere containing oxygen,
In the ethanol solution,
The neutral block copolymer / ethanol which is a mass ratio of the neutral block copolymer to the ethanol is 0.09 or more and 0.11 or less,
Water / ethanol which is a mass ratio of the water to the ethanol is 0.00 or more and 0.015 or less,
Manganese chloride / ethanol which is a mass ratio of the manganese chloride to the ethanol is 0.020 or more and 0.030 or less,
The manufacturing method of the metal oxide porous body whose tantalum chloride / ethanol which is the mass ratio of the said tantalum chloride with respect to the said ethanol is 0.130 or more and 0.190 or less.   The method for producing a metal oxide porous body according to claim 2, wherein the neutral block copolymer is a triblock copolymer of polypropylene oxide (PO) chain-polyethylene oxide (EO) chain-polypropylene oxide (PO) chain.