JP5069881B2 - R-type manganese dioxide nanoneedle porous body and R-type manganese dioxide nanoneedle constituting the same, hydrogenated manganese oxide, infrared absorbing material, infrared filter, and production method thereof - Google Patents

Description

  The present invention relates to an R-type manganese dioxide nanoneedle porous body, an R-type manganese dioxide nanoneedle constituting the porous body, hydrogenated manganese oxide, an infrared absorbing material, an infrared filter, and methods for producing them.

  Porous material (porous material) is a general term for solids having various pores inside and outside, and using the structure and surface properties, heat insulating material, buffer material, sound absorbing material, or adsorption handled in the present invention It is used in many fields as materials and catalyst carriers. This porous material is classified as microporous (2 nm or less), mesoporous (2 to 50 nm), or macroporous (50 nm or more) according to the average pore diameter.

  The world's first synthesis of mesoporous materials with uniform average pore diameters was reported in 1992, regardless of the synthesis method or constituent elements, and they were oxidized using surfactant molecular aggregates as templates. It was a mesoporous material that realized a silicon mesopore structure (see Non-Patent Documents 1 and 2). Such a mesoporous material having a uniform average pore diameter has not yet been industrially practical since it has not been synthesized since the synthesis was actually successful. However, it is a good model substance for studying catalytic reactions and adsorption reactions involving compounds with large molecular diameters, which were too small to enter with microporous pores such as zeolite, or the physical properties of nanomaterials. Therefore, in recent years, research papers on synthesis methods, physical properties, and their applications have increased rapidly. Among them, there are only a few reports regarding manganese oxides, and as a representative example, synthesis with an average pore diameter of 2 nm was reported in 1997 (see Non-Patent Document 3).

  However, the average pore diameter of 2 nm is a boundary region with microporous, and is used as a host material for catalytic reactions involving complex compounds with large molecular diameters such as natural gas, adsorption / deposition reactions of complexes in solution, or nanofunctional materials. Since the pore diameter is small for the purpose of use, there is great expectation in each direction for the manganese dioxide mesoporous material having an average pore diameter of about 10 to 20 nm. Generally, manganese dioxide is classified into α (alpha), β (beta), γ (gamma), ε (epsilon), δ (delta), λ (lambda), and R (R) types depending on the crystal structure. Has been. Among these, the γ type is a crystal structure in which a β type, an ε type, and an R type are mixed. The difference between these crystal structures is because the uniform and regular arrangement of octahedrons (octahedrons with six oxygen atoms coordinated around manganese atoms), which is the smallest unit constituting the crystal, is different. It is well known to occur.

It should be noted that R-type manganese dioxide is conventionally obtained by a hydrothermal synthesis method using a lithium manganese oxide having a spinel crystal structure in which lithium is coordinated in a λ (lambda) type manganese dioxide crystal as a starting material. Is reported (see Non-Patent Document 4), but there is no example of synthesizing R-type manganese dioxide in a nanoscale and needle shape by other synthesis methods.
J. et al. S. Beck et al, J.A. Am. Chem. Soc. , 114, 10834 (1992) J. et al. C. Vartuli et al. , Chem. Mater. , 6, 2317 (1994) Zheng-Rong Tian et al. Science vol. 276 H. Rossouw, J.M. Mater. chem, vol. 2,1992

  Accordingly, the present invention has been made based on the background as described above, and comprises a high specific surface area R-type manganese dioxide nanoneedle porous body composed of nanoscale R-type manganese dioxide nanoneedles and the porous body. It is an object to provide an R-type manganese dioxide nanoneedle, an infrared absorbing material, an infrared filter, and a method for producing them.

The present invention is characterized by the following in order to solve the above problems.
<1> A manganese dioxide nanoneedle porous body comprising needle-shaped nanoneedles mainly composed of R-type manganese dioxide, wherein a mesoporous porous structure is formed by these nanoneedles.
<2> The mesoporous porous structure has an average pore diameter of 3 nm to 30 nm, a BET specific surface area of 40 to 200 m ² / g, and a total pore volume of 0.1 to 0.5 cm ³ / g. The manganese dioxide nanoneedle porous body according to <1>, wherein the porous body is a manganese dioxide nanoneedle.
<3> The mesoporous porous structure has an average pore diameter of 7 nm to 14 nm, a BET specific surface area of 80 to 130 m ² / g, and a total pore volume of 0.2 to 0.5 cm ³ / g. The porous manganese dioxide nanoneedle described in <1> above, wherein
<4> The mesoporous porous structure has an average pore diameter of 15 nm to 30 nm, a BET specific surface area of 40 to 50 m ² / g, and a total pore volume of 0.1 to 0.3 cm ³ / g. The porous manganese dioxide nanoneedle described in <1> above, wherein
<5> Manganese dioxide nanoneedle porous body according to any one of <1> to <4>, wherein the surface hardness is in the range of Vickers hardness of 15 to 35 as measured by the Vickers hardness test method .
<6> Needle-shaped R-type manganese dioxide nanoneedles having a nanometer scale in size and mainly composed of R-type manganese dioxide.
<7> The R-type manganese dioxide nanoneedle according to the above <6>, which has a thickness of 1 to 100 nm and a length of 3 to 900 nm.
<8> The nanoneedle of R-type manganese dioxide according to the above <6>, which has a thickness of 2 to 10 nm and a length of 5 to 30 nm.
<9> The nanoneedle of R-type manganese dioxide according to the above <6>, which has a thickness of 10 to 30 nm and a length of 30 to 300 nm.
<10> A metal-supported R-type manganese dioxide nanoneedle, wherein a metal is supported on the R-type manganese dioxide nanoneedle according to any one of the above items <6> to <9>.
<11> The metal-supported R-type manganese dioxide nanoneedle according to <10>, wherein the metal to be supported is gold or palladium.
<12> Manganese valence + tetravalent hydrogenated manganese oxide HMnO ₂ nanoparticles in which the crystal structure of R-type manganese dioxide MnO ₂ is impregnated with protons H ⁺ and electrons e ⁻ .
<13> Nanoparticles of hydrogenated manganese oxide HMnO _{2 according} to the above <12>, which are in the range of 2 to 10 nm in thickness and 5 to 30 nm in length and are needle-shaped.
<14> Nanoparticles of hydrogenated manganese oxide HMnO _{2 according} to the above <12>, which have a thickness of 10 to 30 nm and a length of 30 to 300 nm and are needle-shaped.
<15> A mesoporous material formed of the manganese dioxide nanoneedle porous material according to any one of <1> to <5>.
<16> The mesoporous material according to <15>, wherein the mesoporous material is a film-like body formed in a film shape.
<17> A method for producing a manganese dioxide nanoneedle porous body, comprising firing manganese carbonate n-hydrate MnCO ₃ .nH ₂ O powder, treating it with acid to form a paste, and then drying.
<18> The method for producing a manganese dioxide nanoneedle porous body according to <17>, wherein bismuth carbonate carbonate is mixed with manganese carbonate n hydrate and fired.
<19> The method for producing a manganese dioxide nanoneedle porous body according to <17> or <18>, wherein the acid treatment is performed at least twice.
<20> A method for producing nanoparticle of hydrogenated manganese oxide HMnO ₂ , which comprises treating the R-type manganese dioxide nanoneedles of <6> to <9> with an acid. .
<21> An infrared absorbing material comprising the porous manganese dioxide nanoneedle according to any one of <1> to <5>.
<22> An infrared filter comprising the infrared absorbing material according to <21> above.
<23> The infrared filter according to the above <22>, wherein the transmitted infrared light has a wavelength range of 10 to 14 μm.

  According to the present invention as described above, a manganese dioxide nanoneedle porous body having a high specific surface area, an R-type manganese dioxide nanoneedle constituting the same, and a production method capable of easily producing them are provided.

  The above manganese dioxide nanoneedle porous body can be applied to a fuel cell electrode material or a base material such as a catalyst carrier, in addition to the properties of a solid acid and the development of novel optical properties.

Furthermore, according to this invention, the infrared rays absorption material using the above manganese dioxide nanoneedle porous body and the infrared filter containing it are provided. Infrared rays have a wavelength as an electromagnetic wave of the order of micrometers and are heat rays in terms of energy. In general, in order to make materials absorb infrared rays, there are known methods of coating and coating a carbon material having a property of absorbing infrared rays on the surface of the material and adding it to the material with a smaller amount of coating and addition. In order to obtain a higher absorption effect, a material having a large heat capacity per unit volume and a high heat insulating property is required. The infrared ray absorbing material of the present application is composed of a manganese dioxide nanoneedle porous body having a BET specific surface area of 40 to 200 m ² / g, and is twice or more heavier than the specific gravity of a normal carbon material. Large heat capacity. For this reason, infrared rays can be efficiently absorbed with a smaller amount of coating and addition.

  In addition, an infrared filter having a characteristic of selectively transmitting only an infrared ray having a specific wavelength in an infrared region having a wavelength of 10 μm or more has not been realized so far, and the infrared filter of the present application realizes this. Yes, it is highly industrially useful.

  Furthermore, since the above manganese dioxide nanoneedle porous body is inexpensive and can be easily produced, the infrared absorbing material and the infrared filter can also be realized at a low cost.

  The present invention has the features as described above, and an embodiment thereof will be described below.

  The manganese dioxide nanoneedle porous body of the present invention is composed of needle-shaped nanoneedles mainly composed of R-type manganese dioxide, and a mesoporous structure is formed of these nanoneedles. Here, the needle-like nanoneedle mainly composed of R-type manganese dioxide is generally composed of 50% or more, preferably 80% or more, and 95% or more of R-type manganese dioxide as a component by weight. The size, that is, the thickness (average diameter) and the length (distance between both ends) are on a nanometer scale, and the thickness is substantially uniform and has a needle shape (also referred to as a rod). In a normal solution reaction, unevenness of the surface occurs in one needle, so that the thickness is non-uniform, or because several needles are obtained in a bundle, It is extremely difficult to obtain a needle having a substantially uniform thickness as in the present invention.

As this manganese dioxide nanoneedle porous body, for example, a mesoporous porous structure having an average pore diameter in the range of 3 nm to 30 nm and a BET specific surface area of 40 to 115 m ² / g is considered. In particular, the average pore diameter is 3 nm to 15 nm and the BET specific surface area is in the range of 50 to 200 m ² / g. In particular, the average pore diameter is 7 nm to 14 nm and the BET specific surface area is in the range of 80 to 130 m ² / g. And those having an average pore diameter of 15 to 30 nm and a BET specific surface area of 40 to 50 m ² / g. In addition, the total pore volume of the mesoporous structure of the manganese dioxide nanoneedle porous body is about 0.1 to 0.5 cm ³ / g.

The R-type manganese dioxide nanoneedles of the present invention have a thickness (average diameter) and length (distance between both ends) in the range of 1 to 100 nm in thickness and 3 to 900 nm in length. Such a nanometer-scale needle-shaped R-type manganese dioxide nanoneedle has never been reported so far and has been realized for the first time by the present inventors. Furthermore, in the present invention, high-purity R-type manganese dioxide nanoneedles can be synthesized in a short time. In the present invention, the R-type manganese dioxide nanoneedles are particularly provided with a thickness of 2 to 10 nm and a length of 5 to 30 nm, and a thickness of 10 to 30 nm and a length of 30 to 300 nm. The R-type manganese dioxide nanoneedles are aggregated and blocked to form a mesoporous porous structure, resulting in a manganese dioxide nanoneedle porous body. In particular, a manganese dioxide nanoneedle porous body composed of nanoneedles having a thickness of 2 to 10 nm and a length of 5 to 30 nm has an average pore diameter of 7 to 14 nm and a BET specific surface area of 80 to 130 m ^{2 in} a mesoporous structure. / G, a porous structure with a total pore volume in the range of 0.2 to 0.5 cm ³ / g is formed. As described later, bismuth carbonate carbonate is mixed with manganese carbonate n-hydrate and fired. Thus, the average pore diameter can be reduced to about 3 nm, and the BET specific surface area can be increased to about 200 m ² / g. Further, the manganese dioxide nanoneedle porous body composed of nanoneedles having a thickness of 10 to 30 nm and a length of 30 to 300 nm has an average pore diameter of 15 to 30 nm and a BET specific surface area of 40 to 50 m ^{2 in} a mesoporous structure. / G, a porous structure having a total pore volume in the range of 0.1 to 0.3 cm ³ / g is formed.

  The manganese dioxide nanoneedle porous body as described above is blocked by entanglement of nanoneedles. The surface hardness of the blocked manganese dioxide nanoneedle porous body is relatively hard. Specifically, the surface hardness is about 15 to 35 as measured by the Vickers hardness test method. Considering that the Vickers hardness of aluminum metal is 50 or more, it can be seen that the surface hardness of the porous manganese dioxide nanoneedle of the present invention is quite high.

The manganese dioxide nanoneedle porous body described above is, for example, a powder of manganese carbonate n-hydrate MnCO ₃ .nH ₂ O is baked and acid-treated to produce hydrogenated manganese oxide HMnO ₂ , which is then paste-like And then dried and solidified.

The firing temperature is preferably in the range of 180 ° C to 210 ° C, for example. When the firing temperature is less than 180 ° C., the thickness of the outer shell of manganese oxide Mn ₂ O ₃ obtained after firing becomes thin on average. As will be described later, the outer shell of the manganese oxide Mn ₂ O ₃ is changed to manganese dioxide MnO ₂ .H ₂ O hydrated during the acid treatment, thereby ^converting manganese ions Mn ²⁺ in the acid treatment solution into hydrogen. While having a role of a phase change in the manganese oxide HMnO ₂ was turned into, that the thickness of the outer shell of manganese oxide Mn ₂ O ₃ becomes thinner, manganese dioxide MnO hydrated for producing the phase change effectively ₂ · H ₂ O is insufficient, and as a result, the manganese dioxide nanoneedles that finally constitute the porous manganese dioxide nanoneedle cannot be sufficiently produced. When the firing temperature exceeds 210 ° C., the outer shell of manganese oxide Mn ₂ O _{3 on} the surface of manganese carbonate obtained after firing becomes thick, and the residual amount of manganese carbonate as a raw material decreases, so that manganese ions during acid treatment Manganese dioxide nanoneedles constituting the manganese dioxide nanoneedle porous body cannot be sufficiently produced due to insufficient manganese component dissolved as Mn ²⁺ . In addition, it is as follows about the detailed description of the above manganese dioxide nanoneedle production | generation.

First, a predetermined amount of manganese carbonate n-hydrate MnCO ₃ .nH ₂ O powder is put in a crucible such as ceramic and fired for a predetermined time in a temperature range of 180 to 210 ° C., for example, in the atmosphere. More preferably, firing is performed under the conditions of 195 ° C. and 6 hours (including the temperature raising time). By firing, the surface of the raw material manganese carbonate n-hydrate powder is oxidized to obtain a manganese carbonate MnCO ₃ powder having an outer shell of manganese oxide Mn ₂ O ₃ .

Next, the manganese carbonate powder having an outer shell of manganese oxide Mn ₂ O ₃ is acid-treated to dissolve and remove manganese carbonate as manganese chloride to generate manganese ions Mn ²⁺ . The manganese ions ^{Mn 2+} to produce manganese oxide HMnO ₂ was hydrogenated by contacting the manganese dioxide _{MnO 2} · _H 2 O hydrated. An outline of this mechanism is shown in FIG.

FIG. 1A shows manganese carbonate particles having an outer shell (coating) of manganese oxide Mn ₂ O ₃ obtained after firing. These manganese carbonate particles are produced by suspending manganese carbonate particles in an acid treatment solution such as dilute hydrochloric acid by acid treatment, so that the manganese oxide Mn ₂ O _{3 in the} outer shell is generated by contact with dilute hydrochloric acid. The manganese dioxide MnO ₂ · H ₂ O is hydrated under the influence of manganese, and the manganese carbonate MnCO ₃ inside the outer shell is changed to manganese chloride MnCl ₂ , carbon dioxide CO ₂ and water H ₂ O (FIG. 1 ( b)). Manganese chloride MnCl ₂ becomes divalent manganese ion Mn ²⁺ , the carbonic acid component becomes carbon dioxide CO ₂ gas and increases the internal pressure inside the outer shell, and as a result, bubbles of carbon dioxide containing manganese ion Mn ²⁺ become water H with ₂ O, ejected through the hydrated manganese dioxide _{MnO 2} · _H 2 O phased shell surface. During the ejection, since the manganese ions ^{Mn 2+} is good contact manganese dioxide _{MnO 2} · _H 2 O and efficiency hydrated outer shell, the oxidation of manganese ions ^{Mn 2+,} forming a manganese oxide HMnO ₂ was hydrogenated (FIG. 1 (c)). And by making this into paste form and drying, the manganese dioxide nanoneedle porous body comprised with the nanoneedle of high purity R-type manganese dioxide can be synthesize | combined in a short time.

The above reaction is considered a catalytic reaction. That is, when powder obtained by mixing manganese oxide Mn ₂ O ₃ which is a component of the outer shell and manganese carbonate MnCO ₃ n hydrate was subjected to acid treatment and drying treatment in the same manner as described above, beta-type Mn ₂ O ₃ And R-type MnO ₂ was not obtained. In addition, a powder obtained by mixing manganese oxide Mn ₂ O ₃ which is a component of the outer shell and manganese carbonate MnCO ₃ n hydrate is kept in dilute hydrochloric acid for 4 months, and this is filtered and dried. Although manganese dioxide is a mixture of R-type MnO ₂ and beta-type MnO ₂ , nanoscale-sized ones were not obtained. From these experimental results, it can be said that the chemical reaction of this method, which made it possible to synthesize highly pure R-type manganese dioxide nanoneedles in a nanoscale in a short time, is a catalytic reaction.

In the present invention, commercially available products can be used as the powder of manganese carbonate n-hydrate MnCO ₃ .nH ₂ O used. For example, in the present invention, manganese carbonate / n hydrate (made by reagent special grade Wako Pure Chemical Industries) is used in Examples described later. In general, the powder of manganese carbonate n-hydrate MnCO ₃ .nH ₂ O has a size of several nanometers to several tens of nanometers of amorphous single crystal particles aggregated to form about 1 to several tens of micrometers. Particles with a particle size are formed. Incidentally, the powder of the manganese carbonate n-hydrate MnCO 3 · _nH 2 _O, it is preferable to use a in a state of uniform sizes immediately after opening the reagent bottle. If the reagent bottle has been opened for a long time, the manganese carbonate n hydrate absorbs moisture over time and the grains become coarse and become non-uniform particle groups. This is not preferable because the thickness and shape of the resulting manganese oxide Mn ₂ O ₃ may not be uniform.

  It is considered that the acid treatment is performed at a temperature in the range of 5 to 60 ° C. Oxidation reaction of manganese ions can be achieved by setting the acid treatment temperature (the temperature of the acid treatment solution) higher than the temperature of the acid treatment solution stored at room temperature or by applying sunlight (ultraviolet rays). The reaction rate is increased, and a large-sized needle can be synthesized. When synthesizing a needle having a larger size, it is effective to keep the temperature of the acid treatment solution at 30 ° C. or higher and to stir the acid treatment solution in a place where it is exposed to sunlight.

The acid used for the acid treatment may be, for example, an inorganic acid such as hydrochloric acid, nitric acid, and sulfuric acid. Among them, manganese oxide Mn ₂ O ₃ produced as an outer shell of manganese carbonate n hydrate after firing is efficiently used. Hydrochloric acid is preferred in order to change the phase to hydrated manganese dioxide MnO ₂ .H ₂ O. As a density | concentration of an acid, it is the range of 0.1-1.0 mol / L, More preferably, it is the range of 0.5-1.0 mol / L.

As described above, the hydrogenated manganese oxide HMnO ₂ is obtained by baking a powder of manganese carbonate n-hydrate MnCO ₃ .nH ₂ O and stirring it in an acid treatment solution such as dilute hydrochloric acid for about 1 to 5 hours. It is obtained by acid treatment, solid-liquid separation with a vacuum filter and recovery. By repeating this treatment at least twice or more, impurities other than HMnO ₂ , such as residual manganese carbonate components and manganese oxide fine particles, can be dissolved and removed. The number of acid treatments is sufficient if the generation of carbon dioxide bubbles generated from the fired manganese carbonate to be acid-treated becomes invisible even after repeated acid treatments. For example, each time a diluted hydrochloric acid is re-poured into a 1 L beaker each time and the number of acid treatments is not repeated, the pH of the diluted hydrochloric acid during the acid treatment is maintained within 0.5 to 0.6 in one beaker. Although the operation of dropping hydrochloric acid in a timely manner may be performed, the pH rises drastically due to the influence of water generated from the dissolution reaction of manganese carbonate, particularly during the first acid treatment. For this reason, the operation of maintaining the pH at 0.5 to 0.6 is not easy without a dedicated titrator. For this reason, in this method, the number of acid treatments is repeated several times.

The recovered material is in the form of a paste in which a large number of nano particles of manganese oxide HMnO ₂ hydrogenated in a state of containing moisture are collected. The hydrogenated manganese oxide HMnO ₂ nanoparticles are indefinite, but the paste is dried to synthesize R-type manganese dioxide nanoneedles, and then the R-type manganese dioxide nanoneedles are acid-treated again. Thus, hydrogenated manganese oxide HMnO ₂ nano-particles that are hydrogenated manganese oxide HMnO ₂ nanoneedles having the same size and shape as the R-type manganese dioxide nanoneedles can be obtained. The acid treatment of the R-type manganese dioxide nanoneedles is the same as the acid treatment of the powdered manganese carbonate n-hydrate MnCO ₃ .nH ₂ O powder.

As described above, the porous manganese dioxide nanoneedle body is obtained by drying the paste. During the drying process, moisture evaporates from the paste, and the hydrogenated manganese oxide is R-type manganese dioxide MnO ₂ nanoparticle. A block having a size of centimeter can be obtained by growing into a needle and intertwining the nanoneedles. In the case where manganese oxide nanoneedles are not obtained and manganese oxide nanoparticles are simply obtained as the main component, or if the removal of the raw material components is incomplete, the material obtained by the drying process is blocked. It does not turn into brittle sand and the surface Vickers hardness is even difficult to measure.

  Also, by applying the above paste to a metal mesh of several hundred meshes (the material of the mesh can be changed depending on the application, such as Teflon (registered trademark) or carbon mesh) during the drying process, The mesh becomes an aggregate, and a film-like body having a shape corresponding to various uses can be produced. Furthermore, it can join by heating at 150-220 degreeC, Preferably it is 200 degreeC in the state which contacted the film-like bodies obtained in this way, and it increases a film thickness easily according to the objective. It is also possible.

When the average pore diameter and the BET specific surface area of the block or film obtained after the above drying treatment were measured by a nitrogen gas adsorption method, the average pore diameter was in the range of 3 to 30 nm, and the BET specific surface area was 40. It turns out that it is a mesoporous porous structure which is the range of -200 m < ² > / g.

The firing of manganese carbonate n-hydrate is carried out in a crucible as described above. As the shape of this crucible, the raw material manganese carbonate MnCO ₃ .nH ₂ O is oxidized to manganese oxide Mn ₂ O _3. It is preferable that the carbon dioxide CO ₂ gas generated when the gas flows out in one direction. Specifically, a shape like a crucible or a test tube having a lid with a small hole in the center is preferable. By making the outflow direction of the carbon dioxide CO ₂ gas one direction, the thickness of the outer shell of manganese oxide Mn ₂ O ₃ obtained after firing can be made constant, and the finally obtained needle-like manganese dioxide The yield of can be improved. When the raw material manganese carbonate MnCO ₃ · nH ₂ O is fired on a flat dish-shaped ceramic plate having a wide opening, for example, the diffusion of CO ₂ gas does not flow out in one direction. The thickness of the outer shell of Mn ₂ O ₃ is not constant, and as a result, the yield of needle-like manganese dioxide is ultimately lowered.

  In addition, although it is considered that an electric furnace is used for firing, this electric furnace has a vent hole to the outside and has a sufficient volume in the furnace in order to uniformly oxidize the surface of manganese carbonate. It is preferable that When the furnace has a volume of only about the size of a crucible containing the raw material and is fired using a sealed electric furnace, the surface of the manganese carbonate is not easily oxidized, which is not preferable.

  In the present invention, by changing the drying conditions of the paste, the size of the resulting manganese dioxide nanoneedles is controlled, and the average pore diameter and the BET specific surface area of the manganese dioxide nanoneedle porous material are adjusted. Can do. For example, the nano-needle of R-type manganese dioxide obtained by drying at 90 to 120 ° C. for 2 to 12 hours in the air, as a drying condition, that is, by increasing the dehydration rate of moisture in the paste Can be made smaller. Specifically, it is possible to form R-type manganese dioxide nanoneedles having a thickness of 2 to 10 nm and a length of 5 to 30 nm.

On the other hand, in order to obtain larger-sized R-type manganese dioxide nanoneedles, the dehydration rate of water in the paste is reduced, or a dilute acid such as dilute hydrochloric acid is added to the paste to add water in the paste. By increasing the amount of hydrogen ions and then drying, R-type manganese dioxide nanoneedles that have grown larger can be obtained. Specifically, it becomes possible to make R-type manganese dioxide nanoneedles having a thickness of 10 to 30 nm and a length of 30 to 300 nm. As described above, the powder of manganese carbonate n-hydrate MnCO ₃ · nH ₂ O is baked, stirred in an acid treatment solution such as dilute hydrochloric acid, and solid-liquid separated with a vacuum filter to obtain a recovered paste. Naturally contains dilute hydrochloric acid. By adding dilute hydrochloric acid to this paste to increase the amount of dilute hydrochloric acid contained in the paste, that is, by increasing the amount of hydrogen ions contained in the paste, Nanoneedles can be obtained. This is because, in the drying process of the paste, the concentration of dilute hydrochloric acid increases as the moisture in the paste evaporates, the hydrogenated manganese oxide dissolves as manganese ions Mn ²⁺ , and the bonds between the hydrogenated manganese oxide particles This is thought to occur. As a method of increasing the amount of hydrogen ions contained in the paste, dilute hydrochloric acid may be newly added to the paste as described above, but the filtration operation is performed when the dilute hydrochloric acid is not sufficiently removed by suction when recovered with a vacuum filter. You may make it stop.

Thus, by adjusting the drying conditions and the amount of hydrogen ions in the paste, the size of the R-type manganese dioxide nanoneedles can be controlled. Therefore, in order to obtain R-type manganese dioxide nanoneedles of a desired size, the nanoneedles are synthesized in advance under predetermined drying conditions, and the size of the nanoneedles is measured appropriately. The target nanoneedle can be obtained by setting conditions. For example, when the target size is larger than the pre-synthesized nanoneedles, the dehydration rate under drying conditions is decreased, or the amount of hydrogen ions contained in the paste is increased. On the other hand, when the target size is smaller than the pre-synthesized nanoneedle, conditions are set so that the dehydration rate in the drying condition is increased or the amount of hydrogen ions in the paste is reduced. By repeating this operation, thin and short R-type manganese dioxide nanoneedles can be made separately from thick and long R-type manganese dioxide nanoneedles. The manganese dioxide nanoneedle porous body in which the R-type manganese dioxide nanoneedles are aggregated to form a mesoporous porous structure has an average pore diameter and a specific surface area that are the same as the thickness and length of the R-type manganese dioxide nanoneedles. Dependent. For example, in a manganese oxide nanoneedle porous body composed of R-type manganese dioxide nanoneedles having a thickness of 2 to 10 nm and a length of 5 to 30 nm, the average pore diameter is in the range of 7 nm to 14 nm, and the BET specific surface area is 80 to 130 m ² / g, and the total pore volume is in the range of 0.2 to 0.5 cm ³ / g. And in the manganese oxide nanoneedle porous body comprised with the nanoneedle of R type manganese dioxide of thickness 10-30 nm and length 30-300 nm, the average pore diameter is in the range of 15-30 nm, and the BET specific surface area is 40- 50 m ² / g, and the total pore volume is in the range of 0.1 to 0.3 cm ³ / g.

  Therefore, the present invention can synthesize a manganese dioxide mesoporous material having an average pore diameter and a specific surface area according to the purpose of use by adjusting the drying conditions and the amount of hydrogen ions contained in the paste.

Further, the present invention is an R-type manganese dioxide finally obtained by mixing bismuth carbonate carbonate with manganese carbonate hydrate as a raw material, and performing firing, acid treatment and drying treatment by the above-described series of methods. It is possible to improve the specific surface area of the mesoporous porous body constituted by the nanoneedle. For example, by mixing bismuth carbonate, the BET specific surface area of the mesoporous porous material is increased by about 1.75 times to about 200 m ² / g and the average pore diameter is reduced to about 3 nm by mixing with bismuth carbonate. be able to. The above bismuth carbonate oxide is considered to play a role as a template to create pores in the finally obtained manganese dioxide mesoporous porous material by dissolving more slowly than manganese carbonate hydrate during acid treatment. . Therefore, as a material that serves as such a template, any material may be used as long as the temperature at which it is changed to an oxide is higher than that of manganese carbonate hydrate and the solubility in the acid treatment solution is lower than that of manganese carbonate. It is not limited to bismuth carbonate oxide.

  The manganese dioxide nanoneedle porous body can be used as an infrared absorbing material. It is effective to evaluate the infrared absorbing ability / transmitting ability as the infrared absorbing material by using an infrared spectrophotometer (FT / IR) as in the examples described later. The measurement with this infrared spectrophotometer is performed by applying an infrared ray in a wavelength region of 2.5 to 25 μm emitted from a ceramic light source with a total output of 170 W to a test body obtained by pressure-molding the above manganese dioxide nanoneedle porous body with a press. Irradiating. For example, when the specimen has a diameter of 10 mm and a thickness of 0.5 mm (error plus or minus 0.1 mm), when the weight of the manganese dioxide nanoneedle porous body in the specimen is 0.2 g or more, the irradiated infrared ray is almost transmitted. It turns out that it absorbs without. It was also found that when the weight of the manganese dioxide nanoneedle porous body in the test specimen was reduced to 0.115 g, infrared transmission was observed in a region of 10 μm or more.

  When actually using manganese dioxide nanoneedle porous material as an infrared absorbing material, the dried manganese dioxide nanoneedle porous material can be applied to the surface of any material or added to the paint to form any surface. Infrared absorption ability can be added. In addition, by applying a paste before drying and solidifying to a cloth such as cloth, and then drying, the infrared ray absorbing ability can be added to the surface of an irregular material such as cloth cloth.

  The present invention also provides an infrared filter containing the above infrared absorbing material. This infrared filter can selectively transmit only infrared rays having a specific wavelength in an infrared region having a wavelength of 10 μm or more. Specifically, for example, when an infrared light having a wavelength region of 2.5 to 25 μm is irradiated from a ceramic light source having a total output of 170 W, the wavelength region is 10 to 14 μm, the half width (from 0% transmittance to the transmittance of the peak top). (Peak width at half height) Infrared rays in the range of 1.2 to 1.6 are transmitted, more preferably in the wavelength region of 12 to 13 μm and half width in the range of 1.3 to 1.5 μm. Is done.

  The above infrared filter can be produced by adding to a transparent material such as glass or resin or KBr powder described later, which transmits infrared rays.

  The performance of this infrared filter can be evaluated by measuring with an infrared spectrophotometer like the above infrared absorbing material. For example, manganese dioxide nanoneedle porous powder and KBr powder are mixed well in an agate mortar at a weight mixing ratio of 1: 15.5, and this is mixed with a press machine with a diameter of 10 mm and a thickness of 0.5 mm (error plus or minus 0). .1 mm) is irradiated with an infrared ray having a wavelength range of 2.5 to 25 μm emitted from a ceramic light source having a total output of 170 W, and the infrared absorption ability and transmission ability are evaluated. The peak top wavelength of the transmission intensity is 12.3 to 12.5 μm, and the half width (peak width at a half height from the transmittance 0% to the peak top transmittance) is 1.36 to 1.49 μm. It can be seen that it exhibits infrared transparency. On the other hand, as will be described later, when commercially available manganese dioxide powder was pelletized under the same conditions and infrared transmittance was measured, a peak due to adsorbed water was observed, and the half-value width of the transmission peak was nearly 10% wider. It was. For this reason, since the infrared absorption capability of the manganese dioxide nanoneedle porous body and the infrared rays in a narrow wavelength region are transmitted, it can be seen that the performance as an infrared filter is excellent.

  Furthermore, when the infrared filter of this application uses the manganese dioxide nanoneedle porous body with a large specific surface area, it exists in the tendency for the infrared rays intensity | strength which permeate | transmits a test body to become low. Therefore, when the output of incident infrared rays is high, infrared rays can be effectively absorbed by using a manganese dioxide nanoneedle porous body having a large specific surface area. Moreover, the infrared filter of this application can control infrared transmittance by selecting the addition amount and specific surface area of a manganese dioxide nanoneedle porous body suitably.

The hydrogenated manganese oxide HMnO ₂ of the present invention is a manganese valence + tetravalent nanoparticle in which proton H ⁺ and an electron e ⁻ are impregnated in the crystal structure of manganese dioxide MnO ₂ , and this hydrogenated manganese oxide is Without additional electrical energy, it has a strong reducing ability to deposit gold complex HAuCl ₄ and palladium complex PdCl ₂ on the surface of hydrogenated manganese oxide as metal gold nanoparticles and metal palladium nanoparticles in water, respectively. ing. Therefore, by using hydrogenated manganese oxide obtained by acid-treating R-type manganese dioxide nanoneedles as described above, metal gold nanoparticles or metal palladium nanoparticles can be deposited on the surface thereof. Therefore, it is possible to obtain metal-supported R-type manganese dioxide nanoneedles on which a metal is supported.

Conventionally reported hydrogenated manganese oxides are Groulite (alpha · MnOOH) and Groutelite (Mn _0.5 Mn _0.5 ) O _1.5 (OH) _0.5 ). R-type manganese dioxide is a chemical species generated by reducing manganese to +3 valence by invasion of proton H ⁺ , and contains at least 40% or more of + 3-valent manganese. Furthermore, these X-ray diffraction patterns show a clear shift of the diffraction peak position depending on the proton content, compared with the X-ray diffraction pattern of R-type manganese dioxide. C. Klingsberg and R.K. Roy, Amer. Mineral. , Vol. 44, pp. 819-838, 1959, L.A. A. H. MacLean and F.M. L. Tye, The Structure of full H-Insert gamma-Manganese Dioxide Conounds, J. Am. Solid State Chem. , Vol. 123, pp. 150-160, 1996, J. MoI. E. Post and P.M. J. et al. Heney, Neutron and synchrotron X-ray diffraction study of the structure and hydration of ramsdello and agroutol. 89, pp. 969-975, 2004.

Considering the above, the hydrogenated manganese oxide of the present invention 1) exhibits the same X-ray diffraction peak position as that of R-type manganese dioxide, and 2) is + 4-valent manganese by X-ray absorption edge analysis. ) A new kind of hydrogenated manganese oxide, which is a new kind of hydrogenated manganese oxide, because it has a strong reducing ability for gold complex and palladium complex which have not been reported in Groulite, which is a conventionally known hydrogenated manganese oxide, and Groutellite. Is considered to be (H ⁺ , e ⁻ ) _x MnO ₂ . In this manganese oxide, since proton H ⁺ is expected to exist between two oxygen atoms O—O, X is 1.0 or less in the chemical formula of (H ⁺ , e ⁻ ) _x MnO _2. It is considered that This hydrogenated manganese is in a state in which proton H ⁺ and electron e ⁻ are in solid solution in the crystal structure of R-type manganese dioxide, and its own electrons are brought into contact with a gold complex or a palladium complex. It is believed that e ⁻ is donated to these complexes and proton H ⁺ is released into water.

  Further, the hydrogenated manganese oxide of the present invention will be described in detail.

  By irradiating the hydrogenated manganese oxide of the present invention with neutrons and examining the inelastically scattered neutrons, the vibration energy of the hydrogen atom-oxygen atom bond contained in the hydrogenated manganese oxide can be measured. The result is shown in FIG.

In FIG. 2, the vertical axis represents the vibration intensity, and the horizontal axis represents the vibration energy. The graph shown by the black circle is the result of irradiating the hydrogenated manganese oxide of the present invention with neutrons, and the other graph is the result of irradiating ice with neutrons for comparison. FIG. 2A is an enlarged view of the vibration energy range of 0 to 50 meV (horizontal axis). In the graph of hydrogenated manganese oxide, the peak detected at 366 meV indicates the presence of proton H ⁺ trapped and oscillating between oxygen atoms and oxygen atoms having a bond distance of 2.57 to 2.60 Å. This is vibration energy of hydrogen atom-oxygen atom bond different from 410 meV which is vibration energy of proton H ⁺ in water H ₂ O contained in manganese oxide hydrogenated by acid treatment. On the other hand, in the ice graph, there is no peak of 366 meV originating from acid treatment, and only OH vibration originating from water is observed. For measurement, an inelastic neutron scattering energy measuring device HRMECS of the Intense Pulsed Neutron Source division at Argonne National Laboratory is used, and the measurement temperature is 9K.

  Table 1 shows oxygen atom-oxygen atom distances existing in manganese dioxide having various crystal structures.

In Table 1, it can be seen that the crystal structure of R-type manganese dioxide has oxygen atom-oxygen atom distances of 2.573 and 2.589Å. Oxygen-oxygen corresponding to a bond distance of 2.57 to 2.60 km, which is information obtained from the result of the previous neutron irradiation experiment, is thus present in the crystal of R-type manganese dioxide. Therefore, it can be seen that the proton H ^{+ which} has entered the crystal of R-type manganese dioxide by the acid treatment is trapped between oxygen atoms and oxygen atoms having bond distances of 2.573 and 2.589 and is dissolved.

  The oxygen atom-oxygen atom bond having an interatomic distance of 2.589 cm forms a network along the b-axis direction of the crystal structure of R-type manganese dioxide, as shown in FIG.

For this reason, it is considered that the proton H ^{+ that} has entered the crystal of R-type manganese dioxide diffuses and conducts along this network. The b direction in which this network exists is also the growth direction of the length of the R-type manganese dioxide nanoneedles. For this reason, the mechanism by which the length of the nanoneedle grows is considered to be related to a phenomenon in which proton H ⁺ invading by the acid treatment is network-conducted. In general, gamma-type manganese dioxide, which consumes 200,000 tons per year as a battery material, contains an epsilon-type crystal structure and a beta-type crystal structure as impurities in the R-type crystal structure. In the crystal structure of these impurities, as shown in Table 1, there is no oxygen atom-oxygen atom bond having a bond distance of 2.57 to 2.60 mm. For this reason, the network which conducts proton H ⁺ will be interrupted in the location where those impurities exist.

For this reason, the R-type manganese dioxide of the present application in which high-purity R-type crystals are obtained as highly reactive nanoparticles includes a battery material with less energy loss related to conduction of protons H ⁺ and electrons e ⁻ accompanied by protons. As expected.

The maximum number of protons H ⁺ and electrons e ⁻ that can be dissolved in hydrogenated manganese oxide is equal to the number of oxygen atom-oxygen atom bonds with bond lengths of 2.573 and 2.589Å existing in the crystal. it is conceivable that. In addition, since the bonds between oxygen atoms and oxygen atoms having such interatomic distances form a regular network in the crystal structure, protons H ⁺ and electrons e trapped between these oxygen atoms and oxygen atoms. ^-Is also considered to be distributed at a uniform density within the crystal. For this reason, compared with the case where only the electrons e ⁻ are present in the crystal of manganese dioxide, there is an advantage that local electric field concentration hardly occurs on the surface of manganese dioxide. Therefore, as described above, metal gold nanoparticles or metal palladium nanoparticles can be deposited on the surface of the hydrogenated manganese oxide of the present application. However, the deposition state is uniform and high density of the metal nanoparticles. Precipitation can occur on the surface. Metallic palladium has the property of decomposing hydrogen gas H ₂ into proton H ⁺ and allowing it to penetrate into the crystals of palladium as Pd—H bonds. Manganese oxide that deposits is expected to be applied in the field of cracking catalysts for hydrogen gas and hydrocarbon gas.

  Hereinafter, examples will be shown and described in more detail. Of course, the present invention is not limited by the following examples.

<Example 1> Synthesis and characteristics of mesoporous porous material composed of R-type manganese dioxide nanoneedles having a thickness of 2 to 10 nm and a length of 5 to 30 nm Reagent-grade manganese carbonate n-hydrate MnCO ₃ · nH ₂ O (Wako pure Chemical) 25 g of the crucible alumina placed in (a crucible having an inner diameter of 6 cm, depth 5 cm, the inner diameter 5mm gas outflow hole at the center of the lid), under atmospheric pressure, at 195 ° C., the temperature Firing was performed using an electric furnace for a total of 6 hours including warm time. At that time, the rate of temperature increase from room temperature to 195 ° C. was 3 ° C./min. Next, 50 g of the powder obtained by firing was suspended in 1 L of dilute hydrochloric acid having a water temperature of 14 ° C. and a concentration of 0.5 M, and stirred with a magnetic stirrer for 1 hour. At the time of stirring, a magnetic stirrer was installed in a place where the suspension was exposed to sunlight that passed through the ground glass of the laboratory window and stirred. Manganese oxide was collected from the suspension after stirring for 1 hour on a filter paper with a vacuum filter to obtain a wet paste. The paste was again acid-treated under the same conditions as described above twice. Therefore, the acid treatment was performed three times on the calcined manganese carbonate n-hydrate. Finally, the acid-treated paste was washed with 100 mL of pure water and stored in a glass sealed container as it was.

  10 g was taken out from the wet paste stored in the glass sealed container, transferred to a glass petri dish, and dried in a dryer at 110 ° C. for 6 hours under atmospheric pressure. From the solidified block after drying, the necessary amount for observation by a transmission electron microscope and surface analysis by a nitrogen gas adsorption method was sampled and observed and analyzed according to each measurement procedure. As a result, it was observed by observation with a transmission electron microscope that nanoneedles having a thickness of 2 to 10 nm and a length of 5 to 30 nm were aggregated in a state where voids were formed (see FIG. 4). Moreover, the photograph which observed the front-end | tip part of nanoneedle is shown in FIG. From FIG. 5, it was confirmed that the tip of the nanoneedle has a rounded shape (rounded corners). In addition, the transmission electron microscope JEM-ARM1000 made from JEOL was used for imaging | photography of a TEM photograph.

Further, from the surface analysis by the nitrogen gas adsorption method, the sampled material is mesoporous having an average pore diameter of 11.7 nm (see FIG. 6), a BET specific surface area of 109.35 m ² / g, and a total pore volume of 0.32 cm ³ / g. It confirmed that it was a porous body. For measurement of the average pore diameter and the BET specific surface area, ASAP2020 manufactured by Shimadzu Corporation-Micromeritics was used.

  In addition, X-ray diffraction analysis of the material sampled from the block revealed that the chemical composition of the block was R-type manganese dioxide, and that no diffraction peak originating from manganese carbonate was observed in the X-ray diffraction pattern. It was confirmed that no manganese carbonate remained. In addition, a Rigaku X-ray diffraction analyzer RAD-IIB was used for the X-ray diffraction analysis.

The surface hardness of the block was measured by the Vickers hardness test method. In the measurement, the surface of the block was coated with a gold thin film by the sputtering method, thereby increasing the reflectance of the surface and measuring the size of the test indentation. As a result of the measurement, it was found that the block surface had a Vickers hardness of 24. For measurement of Vickers hardness, a micro Vickers hardness tester HMV-2000 manufactured by Shimadzu Corporation was used.
<Example 2> Synthesis and properties of mesoporous porous material composed of R-type manganese dioxide nanoneedles having a thickness of 10 to 30 nm and a length of 30 to 300 nm Reagent-grade manganese carbonate n-hydrate MnCO ₃ · nH ₂ O (Wako pure Chemical) 25 g of the crucible alumina placed in (a crucible having an inner diameter of 6 cm, depth 5 cm, the inner diameter 5mm gas outflow hole at the center of the lid), atmospheric pressure, preheated to 200 ° C. It was quickly installed in the electric furnace in the above state and baked for a total of 6 hours including the temperature rising time. Next, 50 g of the powder obtained by firing was suspended in 1 L of dilute hydrochloric acid having a water temperature of 32 ° C. and a concentration of 0.5 M, and stirred for 2 hours with a magnetic stirrer. When stirring, a magnetic stirrer was installed in a place where the suspension was exposed to sunlight and stirred. Since the day of the experiment was a clear day in August, the water temperature of the dilute hydrochloric acid used for the acid treatment was high, and the sunlight was irradiated through the transparent glass in the laboratory, so that the oxidation of manganese ions It is considered that the reaction was promoted compared to the cases of Example 1 and Example 3. Manganese oxide was collected from the suspension after stirring for 2 hours and 30 minutes on a filter paper with a vacuum filter to obtain a wet paste. The paste was again acid-treated under the same conditions as described above twice and collected on a filter paper with a vacuum filter to obtain a wet paste. Therefore, the acid treatment was performed three times on the calcined manganese carbonate n-hydrate.

  Add 2 mL of 0.5 M dilute hydrochloric acid dropwise to the wet paste on the filter paper, and then wrap the paste with 2 sheets of filter paper sufficiently containing 0.5 M dilute hydrochloric acid in a glass bottle with a height of 80 mm and an inner diameter of 30 mm. Inserted. Then, this glass bottle was dried at 100 ° C. under atmospheric pressure in a dryer. From the solidified block after drying, a necessary amount was sampled for observation by a transmission electron microscope (TEM) and surface analysis by a nitrogen gas adsorption method, and observed and analyzed according to each measurement procedure. As a result, it was observed by observation with a transmission electron microscope that nanoneedles having a thickness of 10 to 30 nm and a length of 30 to 300 nm were aggregated in a state where voids were formed (see FIGS. 7 and 8). Moreover, the photograph which observed the front-end | tip part of nanoneedle is shown in FIG. From FIG. 9, it was confirmed that the tip of the nanoneedle has a rounded shape. FIG. 10 is a high-resolution photograph of FIG. In FIG. 10, the disorder of the crystal on the (101) plane can be observed. The high contrast of the electron diffraction pattern obtained by the lower right image processing indicates the high crystallinity of this sample. In addition, the transmission electron microscope JEM-ARM1000 made from JEOL was used for imaging | photography of a TEM photograph.

Further, from the surface analysis by the nitrogen gas adsorption method, the sampled material is mesoporous having an average pore diameter of 18.68 nm (see FIG. 11), a BET specific surface area of 46.47 m ² / g, and a total pore volume of 0.22 cm ³ / g. It confirmed that it was a porous body. For measurement of the average pore diameter, BET specific surface area, and total pore volume, ASAP2020 manufactured by Shimadzu Corporation-Micromeritics was used.

  In addition, by performing X-ray diffraction analysis of the material sampled from the block, the block is mainly composed of R-type manganese dioxide, and no diffraction peak derived from manganese carbonate is observed in the X-ray diffraction pattern. From this, it was confirmed that the raw material manganese carbonate did not remain (see FIG. 12). In the figure, the number next to the rhombus indicates the theoretical diffraction angle peak position of the X-ray diffraction peak of R-type manganese dioxide. It can be seen that the sample of the present invention shows a peak at the theoretical diffraction angle peak of R-type manganese dioxide. In addition, a Rigaku X-ray diffraction analyzer RAD-IIB was used for the X-ray diffraction analysis.

The surface hardness of the block was measured by the Vickers hardness test method. In the measurement, the surface of the block was coated with a gold thin film by the sputtering method, thereby increasing the reflectance of the surface and confirming the size of the test indentation. As a result of the measurement, it was found that the block surface had a Vickers hardness of 27. For measurement of Vickers hardness, a micro Vickers hardness tester HMV-2000 manufactured by Shimadzu Corporation was used.
Example 3 Experiment for Improving the Specific Surface Area of a Mesoporous Porous Material Constructed by R-type Manganese Dioxide Nanoneedles with a Thickness of 2 to 10 nm and a Length of 5 to 30 nm Reagent-specialized manganese carbonate n-hydrate MnCO 25 g of ₃ · nH ₂ O (manufactured by Wako Pure Chemical Industries, Ltd.) and 2.5 g of reagent special grade bismuth (III) carbonate and Bi ₂ (CO ₃ ) O ₂ are mixed well in an agate mortar. The mixed powder was transferred to an alumina crucible (the inner diameter of the crucible was 6 cm, the depth was 5 cm, the inner diameter of the gas outlet hole at the center of the lid was 5 mm), and the total pressure was 6 at 195 ° C., including the temperature rising time. Baking using an electric furnace for an hour. At that time, the rate of temperature increase from room temperature to 195 ° C. was 3 ° C./min. Next, 25 g of the powder obtained by firing was suspended in 1 L of dilute hydrochloric acid having a water temperature of 12 ° C. and a concentration of 0.5 M, and stirred with a magnetic stirrer for 1 hour. When stirring, a magnetic stirrer was placed in a place where the suspension was exposed to sunlight transmitted through the ground glass of the laboratory. Manganese oxide was collected from the suspension after stirring for 1 hour on a filter paper with a vacuum filter to obtain a wet paste. The paste was again acid-treated under the same conditions as described above twice. Therefore, the acid treatment was performed a total of three times on the powder obtained by firing the mixed powder of manganese carbonate n-hydrate and bismuth carbonate carbonate. Finally, the acid-treated paste was washed with 100 mL of pure water and then stored in a glass sealed container in a wet state.

  2 g was taken out from the wet paste stored in the glass sealed container, transferred to a glass petri dish, and dried in a dryer at 110 ° C. for 6 hours under atmospheric pressure. From the solidified block after drying, a necessary amount was sampled for observation by a transmission electron microscope (TEM) and surface analysis by a nitrogen gas adsorption method, and observed and analyzed according to each measurement procedure. As a result, it was observed by observation with a transmission electron microscope that nanoneedles having a thickness of 2 to 10 nm and a length of 5 to 30 nm were aggregated in a state where voids were formed. Moreover, the enlarged photograph of one nanoneedle is shown in FIG. According to FIG. 13, it was observed that the nanoneedle was about 6 nm thick. Moreover, the photograph which observed the front-end | tip part of nanoneedle is shown in FIG. From FIG. 14, it was confirmed that the tip of the nanoneedle has a rounded shape. In addition, the transmission electron microscope JEM-ARM1000 made from JEOL was used for imaging | photography of a TEM photograph.

From the surface analysis by the nitrogen gas adsorption method, the sampled material is a mesoporous material having an average pore diameter of 9.26 nm, a BET specific surface area of 173.29 m ² / g, and a total pore volume of 0.40 cm ³ / g. confirmed.

In addition, when the amount of bismuth carbonate mixed with 25 g of manganese carbonate n-hydrate was increased to 5 g, manganese dioxide nanoneedles of the same size were finally obtained by the method under the same conditions as described above. As a result, it was confirmed that a mesoporous material having an average pore diameter of 5.487 nm, a BET specific surface area of 190.93 m ² / g, and a total pore volume of 0.263 cm ³ / g was obtained.

By mixing a small amount of bismuth carbonate carbonate in this way, the BET specific surface area of the finally obtained mesoporous porous block composed of R-type manganese dioxide nanoneedles was synthesized under the same conditions. It was confirmed that the effect of increasing the BET specific surface area of 109.35 m ² / g (Example 1) when not mixed by about 1.59 times to 1.75 times was obtained. In addition, Shimadzu Corporation ASAP2020 was used for the measurement of an average pore diameter and a BET specific surface area.

Also, by performing X-ray diffraction analysis of the material sampled from the block, the block is mainly composed of R-type manganese dioxide, and the X-ray diffraction pattern has a diffraction peak originating from manganese carbonate, and carbonic acid oxidation. It was confirmed that almost no peaks originating from bismuth and bismuth oxide were observed. Therefore, the raw material manganese carbonate and bismuth carbonate oxide hardly remain in the block, and bismuth oxide Bi ₂ which becomes an impurity from the viewpoint of the chemical composition of the porous body when firing at a low temperature such as 195 ° C. It was confirmed that O ₃ was not generated. In addition, a Rigaku X-ray diffraction analyzer RAD-IIB was used for the X-ray diffraction analysis.

The surface hardness of the block was measured by the Vickers hardness test method. In the measurement, the surface of the block was coated with a gold thin film by the sputtering method, thereby increasing the reflectance of the surface and confirming the size of the test indentation. As a result of the measurement, it was found that the block surface had a Vickers hardness of 20. For measurement of Vickers hardness, a micro Vickers hardness tester HMV-2000 manufactured by Shimadzu Corporation was used.
<Example 4> In synthesizing nano-needle of R-type manganese dioxide having a thickness of 2 to 10 nm and a length of 5 to 30 nm, an experiment for confirming the influence of the water temperature of dilute hydrochloric acid used during acid treatment, and hydrogenation were performed. Experiment confirming that the crystal structure of manganese oxide HMnO ₂ is disturbed Reagent-grade manganese carbonate n-hydrate MnCO ₃ · nH ₂ O (manufactured by Wako Pure Chemical Industries) 25 g of alumina crucible (crucible inner diameter 6 cm, depth 5 cm, the inner diameter of the gas outlet hole at the center of the lid 5 mm), and baked in an electric furnace at 200 ° C. under atmospheric pressure for a total of 6 hours including the temperature rising time. At that time, the rate of temperature increase from room temperature to 195 ° C. was 5 ° C./min. Next, 5 g of the powder obtained by firing was suspended in 100 mL of dilute hydrochloric acid having a water temperature of 14 ° C. and a concentration of 0.5 M, or 100 mL of dilute hydrochloric acid having a water temperature of 35 ° C. and a concentration of 0.5 M, respectively. Stir for 1 hour. At the time of stirring, a magnetic stirrer was installed and stirred in a place where each suspension was exposed to sunlight transmitted through the ground glass of the laboratory window. Manganese oxide was collected from each suspension after stirring for 1 hour on a filter paper with a vacuum filter to obtain a wet paste. The paste was again acid-treated under the same conditions as described above twice. Therefore, the acid treatment was performed three times on the calcined manganese carbonate n-hydrate. Each paste after acid treatment obtained when the temperature of the diluted hydrochloric acid during the acid treatment was 14 ° C. and 35 ° C. was stored in a glass sealed container in a state moistened with diluted hydrochloric acid.

  10 g of each was taken out from the wet paste stored in a glass sealed container, transferred to a glass petri dish, and dried at 110 ° C. for 2 hours under atmospheric pressure in a dryer. A necessary amount for observation with a transmission electron microscope was sampled from each solidified block after drying, and observed according to a measurement procedure. As a result, when the water temperature of the acid during the acid treatment was 14 ° C., it was observed that nanoneedles having a thickness of 3 nm and a length of 10 nm were aggregated in a state where voids were formed. On the other hand, when the water temperature during the acid treatment was 35 ° C., it was observed that nanoneedles having a thickness of 3 to 8 nm and a length of 20 to 30 nm were aggregated in a state where voids were formed. Thus, it was found that a nanoneedle having a large size can be obtained when the temperature of the acid used during the acid treatment is high. In addition, the transmission electron microscope JEM-ARM1000 made from JEOL was used for imaging | photography of a TEM photograph.

Next, each paste immediately after the acid treatment and the change in crystal structure produced when each paste was dried under the above drying conditions were examined by X-ray diffraction analysis. As a result, as shown in FIG. 15, when the acid water temperature is 14 ° C., the paste immediately after the acid treatment (main component is HMnO ₂ ) shows a very broad X-ray diffraction peak (a), and the proton H ⁺ As a result, the regularity of the crystal structure was weakened by the penetration. When this paste sample was dried, an X-ray diffraction pattern having a diffraction angle characteristic of R-type manganese dioxide as shown in FIG.

On the other hand, when the water temperature of the acid is as high as 35 ° C. as shown in FIG. 16, the specific surface area becomes small due to the large size of the nanoneedle, as is apparent from the previous transmission electron microscope observation results. As a result, the penetration amount of proton H ⁺ is reduced, and as a result, the diffraction pattern (a) of the paste immediately after acid treatment (main component is HMnO ₂ ) has the same strength as the diffraction pattern (b) of R-type manganese dioxide after drying. X-ray diffraction peaks are observed. It can be seen that the paste of (a) also has a crystal structure of R-type manganese dioxide as shown in FIG. In addition, Rigaku X-ray diffraction analyzer RAD-IIB was used for these X-ray diffraction analyses.
<Example 5> Evaluation of purity of R-type manganese dioxide The purity of R-type manganese dioxide obtained in Example 1 was evaluated by X-ray diffraction analysis. Purity is an index indicating strain of manganese dioxide crystal, “strain coefficient” Jahn-Teller distortion factor (Y. Chabre and J. Pannetier, Structural and electrochemicals of the Prot. Vol. 23, pp. 1-130, 1995). Sweetsugu, K. et al. Sekitani and T. Shoji, An investigation of structural water inductive diode (EMD), TOSOH, Research & Technology Review, Vol. 49, pp. It was calculated and evaluated according to the calculation method of 21-27, 2005. As a result of the calculation, the strain coefficient obtained in the case of the R-type manganese dioxide of the present application is 0.957, and the purity of the R-type manganese dioxide having a purity of 100% which is not mixed with other crystal structures such as the beta type and the epsilon type is 100%. A value very close to the theoretical distortion coefficient value of 0.95 was obtained. As a comparative example of purity, conditions for obtaining high-purity R-type manganese dioxide using an electrolytic method, which is a general technique for industrially synthesizing manganese dioxide (anode current 12 A / m ² , 9 × 10 ⁴ C, dioxide dioxide) If 50 mm × 100 mm is used for the electrode on which manganese is deposited, the strain coefficient of R-type manganese dioxide obtained when synthesized in the case of 17 days for deposition is 0.96 or more. Considering this value, it becomes clear that the R-type manganese dioxide of the present application is extremely high in purity and can be synthesized in a very short time of 1 to 3 hours by a catalytic reaction in an aqueous solution that does not require additional electrical energy. It was.

In calculating the distortion coefficient, d ₍₂₁₀₎ = 2.424, d ₍₂₁₁₎ , which is a lattice multiplier obtained from the X-ray (Cu-Kα) diffraction pattern of R-type manganese dioxide obtained by the method of the present application. = 2.127, d ₍₆₁₀₎ = 1.359 Å was used. At this time, the a, b, and c axes, which are three-dimensional axes that determine the crystal axis, are set in C.I. Fong, B.B. J. et al. Kennedy, M.M. M.M. Elcombe, A powder neutron diffraction study of lambda and gamma manganese dioxide and of LiMn2O4, Zeitschrift Fuel Kristallogography. 209, pp. 941-945, 1994.
<Example 6> Types of acids used for acid treatment In Example 2, acid treatment was performed using dilute sulfuric acid having a concentration of 0.5M instead of dilute hydrochloric acid having a concentration of 0.5M. Also, the acid added to the acid-treated paste and the acid contained in the filter paper packaging the paste were dried under the conditions of Example 2 using dilute sulfuric acid with a concentration of 0.5 M instead of dilute hydrochloric acid. The obtained sample was subjected to X-ray diffraction analysis. As a result, an X-ray diffraction pattern specific to R-type manganese dioxide was obtained. For this reason, it was found that R-type manganese dioxide was obtained even when sulfuric acid having a lower unit price than hydrochloric acid was used. However, since the intensity of the X-ray diffraction pattern of the obtained R-type manganese dioxide is slightly lower than when dilute hydrochloric acid is used for acid treatment under the same conditions, it is rare to promote the growth of R-type manganese dioxide. It can be said that it is preferable to use dilute hydrochloric acid rather than sulfuric acid. Similarly, R-type manganese dioxide was obtained even when dilute nitric acid was used for the acid treatment instead of dilute hydrochloric acid.
Example 7 Evaluation of Hydrogenated Manganese Oxide 25 g of powder obtained by heating manganese carbonate n-hydrate at 200 ° C. for 6 hours was suspended in 1 L of 0.5 M dilute hydrochloric acid, stirred for 1 hour, and collected by filtration. To obtain a paste. Furthermore, a series of acid treatments such as suspending this paste in 1 L of 0.5 M dilute hydrochloric acid and stirring for 1 hour were repeated twice (therefore, the acid treatment was performed three times in total), and the paste was collected by filtration. This was applied to a glass plate and immediately loaded into a powder X-ray diffraction analyzer for analysis. In addition, 2 mL of 0.5 M dilute hydrochloric acid was added dropwise to this paste and packaged with filter paper containing the dilute hydrochloric acid, then inserted into a glass bottle with a height of 80 mm and an inner diameter of 30 mm, and kept at 100 ° C. under atmospheric pressure for 12 hours in the dryer. -R type manganese dioxide was obtained by drying treatment. The mass of R-type manganese dioxide was pulverized with an agate mortar and pressed onto a glass plate to perform powder X-ray diffraction analysis. FIG. 17 shows the results of X-ray diffraction analysis of the paste and R-type manganese dioxide (R-MnO ₂ ) obtained by drying the paste.

In FIG. 17, the paste and R-type manganese dioxide (R—MnO ₂ ) show peaks at the same diffraction angle. This indicates that the crystal structure of the material constituting the paste has the same crystal structure as that of R-type manganese dioxide. Moreover, the peak related to the (101) plane of the paste is broader than the peak of the (101) plane of R-type manganese dioxide, and the (101) plane of the paste is strongly influenced by the invasion of proton H ⁺ and has a crystal structure. You can see that it is disturbed. In addition, the diffraction peak shown by the line at the bottom in FIG. 17 is a literature value (C. Fong, B. J. Kennedy, MM Elcombe, A powder neutron diffractive study of lambda ampere and gammadane 2, The theoretical diffraction peak position of R-type manganese dioxide according to Zeitschrift Fuel Kristalography, Vol. 209, pp. 941-945, 1994) is shown. The measurement used Rigaku RAD-II B.

  Moreover, the analysis result of the manganese valence by the X-ray absorption edge analysis (XANES) of a paste is shown in FIG. In the measurement of XANES, in order to prevent the paste from drying, it was sealed in a polyethylene bag transparent to X-rays to obtain a measurement sample, and Rigaku R-XAS Looper was used for the measurement.

In FIG. 18, the position of the X-ray absorption edge of the paste occurs at substantially the same position as the manganese dioxide MnO ₂ measured as the standard sample, and what is the absorption edge of the standard sample of Mn ₂ O ₃ that is + trivalent manganese It has become clear that it occurs in different locations.

From the above results, it is confirmed that the paste is a manganese valence + tetravalent hydrogenated manganese oxide HMnO ₂ in which the crystal structure of R-type manganese dioxide MnO ₂ is impregnated with protons H ⁺ and electrons e ^−. It was.
<Example 8> Synthesis of R-type manganese dioxide nanoneedles supported on metal palladium The R-type manganese dioxide nanoneedles produced in Example 2 were sufficiently ground in an agate mortar and suspended in 1 L of 0.5 M dilute hydrochloric acid. After stirring for 1 hour, the paste consisting of nanoneedles was collected on the filter paper with a vacuum filter. Next, 100 mL of a palladium chloride aqueous solution (manufactured by Kishida Chemical Co., Ltd.) having a palladium concentration of 10,000 ppm was transferred to a beaker and adjusted to pH 6.2 using sodium hydroxide pellets and an aqueous solution of sodium hydroxide. In this pH-adjusted palladium chloride aqueous solution, a paste composed of nanoneedles collected on a filter paper was suspended and stirred for 24 hours. Since the pH of the aqueous palladium solution in which the nanoneedles are suspended decreases as the precipitation of palladium proceeds, an aqueous sodium hydroxide solution was added dropwise in a timely manner so as to maintain pH 6.0 during stirring. After 24 hours of stirring, the paste suspended in an aqueous palladium solution was collected on a filter paper using a vacuum filter, then transferred to a glass petri dish, and dried at 100 ° C. under atmospheric pressure for 12 hours using an electric furnace. By such a series of operations, R-type manganese dioxide nanoneedles carrying metal palladium nanoparticles were obtained. The result of observation with a transmission electron microscope is shown in FIG.

In order to deposit palladium on the nanoneedle, it is necessary to transfer the electrons contained in the nanoneedle itself to the palladium complex for reduction. In addition, the pH of the aqueous palladium solution in which the nanoneedles are suspended during the palladium reduction / precipitation reaction is lowered. From these facts, this nanoneedle is a nanoparticle of hydrogenated manganese oxide of manganese valence + tetravalence in which the crystal structure of R-type manganese dioxide MnO ₂ is impregnated with proton H ⁺ and electron e ^−. Recognize. The chemical formula of R-type manganese dioxide supporting nanoparticles of metal palladium is that hydrogenated manganese oxide (H ⁺ , e ⁻ ) _x MnO ₂ nanoparticles are converted to palladium chloride (+ divalent palladium) PdCl ₂ in an aqueous solution. Since two electrons are supplied and deposited as metallic palladium Pd, it is considered to be Pd _{x / 2} MnO ₂ .

  The R-type manganese dioxide nanoneedles obtained in Example 2 were acid-treated, and the filtered and recovered paste was applied to a glass plate and analyzed by X-ray diffraction. The position of the diffraction angle of the R-type manganese dioxide nanoneedles It was confirmed that there was almost no deviation.

The important point in this synthesis method is that after synthesizing the R-type manganese dioxide nanoneedles once, the surface of the R-type manganese dioxide nanoneedles is hydrogenated by acid treatment again, and then added to an aqueous palladium chloride solution. Suspending and depositing palladium on the surface of the nanoneedle. Immediately after the acid treatment of the calcined manganese carbonate, when it is brought into contact with the palladium chloride aqueous solution under the same conditions, a bulky R in which metallic palladium nanoparticles (dense points of dark contrast) are deposited as shown in FIG. Type manganese dioxide is obtained and cannot be obtained in the form of needles. This is because, in the precipitation reaction in an aqueous palladium solution, protons H ⁺ are neutralized to hydroxyl groups OH ⁻ in water when protons H ⁺ are released into the aqueous palladium solution of about pH 6 with the supply of electrons from the hydrogenated manganese oxide. Therefore, it is considered that the paste in which palladium is deposited lacks the proton H ⁺ flowing through the oxygen-oxygen bond network described above, and does not grow as a nanoneedle even if the paste is dried.
<Example 9> Synthesis of nanoneedle of R-type manganese dioxide carrying metal gold In Example 8, instead of an aqueous palladium chloride solution with a palladium concentration of 10000 ppm, an aqueous solution of HAuCl ₄ with a gold concentration of 1000 ppm "reagent name: standard reagent for atomic absorption analysis gold When the same operation was performed using “1000 ppm” (Wako Pure Chemical Industries), it was confirmed that R-type manganese dioxide nanoneedles carrying metal gold nanoparticles were obtained.
<Example 10> Preparation of mesoporous porous membrane of R-type manganese dioxide from acid-treated paste When the acid-treated paste obtained during the synthesis of Examples 1 to 3 was dried, the diameter was 3 cm, The paste was applied to a 300 mesh stainless steel net and dried at 100 ° C. for 7 hours. As a result, the mesh became an aggregate, and a membrane carrying a mesoporous material composed of R-type manganese dioxide nanoneedles having a shape corresponding to the shape and area of the mesh could be produced. Furthermore, the membranes could be joined to each other by leaving them in a heater heated to 200 ° C. with the surfaces of the membranes thus obtained in contact with each other. For this reason, it has been proved that the film thickness can be easily increased by increasing the number of bonded members in accordance with the purpose.
Example 11 Evaluation of Infrared Absorbing Capacity of Infrared Absorbing Material Consisting of Porous Manganese Dioxide Nanoneedle Body Average pore diameter obtained in Example 2 18.68 nm, BET specific surface area 46.47 m ² / g, total pores Crush 0.115 g of manganese dioxide nanoneedle porous material with a volume of 0.22 cm ³ / g in an agate bowl, place it in a pressure molding jig, and compress it at a pressure of 4 MPa for 3 minutes while degassing it with a rotary pump. Thus, a test specimen pellet (infrared absorbing material) having a diameter of 10 mm and a thickness of 0.5 mm was prepared.

This specimen pellet is placed in an infrared spectrophotometer, irradiated with infrared rays having a wave number of 4000 to 400 cm ⁻¹ (wavelength 2.5 to 25.0 μm), and the intensity and wave number of infrared rays transmitted through the specimen pellet ( Wavelength). The measurement results are shown in FIG. In FIG. 21, when the wave number is 1000 cm ⁻¹ or less (10.0 μm or less), the transmittance on the vertical axis is 0.01% or less, and it can be seen that infrared rays are absorbed in most wavelength regions. Permeation is observed when the wave number is 1000 cm ⁻¹ or more (10.0 μm or more). This is because the amount of the manganese dioxide nanoneedle porous material in the test specimen pellet is as very small as 0.115 g. It was confirmed that the transmission intensity at a wave number of 1000 cm ⁻¹ or more (10.0 μm or more) rapidly decreases as the amount of the manganese dioxide nanoneedle porous material is increased. For the measurement, a Fourier transform infrared spectrophotometer FT-IR4200TYPE-A manufactured by JASCO was used. Moreover, it was confirmed that it was extremely difficult to try to observe the test specimen pellet with an optical microscope even when a strong observation light source was irradiated. This is because the manganese dioxide nanoneedle porous body has higher absorbability not only for infrared rays but also for visible light as compared with carbon materials typified by graphite and the like. This is an advantage compared to excellent carbon materials. In addition, the Fourier transform infrared spectrophotometer FT-IR4200TYPE-A made from JASCO was used for the measurement of infrared absorption.
<Example 12> Evaluation of infrared absorbing ability of infrared filter (1)
0.0286 g of a manganese dioxide nanoneedle porous material having an average pore diameter of 9.26 nm, a BET specific surface area of 173.29 m ² / g, and a total pore volume of 0.40 cm ³ / g obtained in Example 3 was added to a KBr powder in an amount of 0. It is pulverized and mixed together with 4362 g in an agate bowl, put in a pressure molding jig, compressed with a pressure of 4 MPa for 3 minutes while degassing with a rotary pump, and 10 mm in diameter and 0.5 mm in thickness (plus Minus 0.1 mm) test specimen pellets were prepared. Therefore, the mixing weight ratio of the nano needle porous body of manganese dioxide and KBr in this test body pellet is 1: 15.3. Moreover, the manganese dioxide nanoneedle porous body density | concentration is 6.15 wt%.

This specimen pellet is placed in an infrared spectrophotometer, irradiated with infrared rays having a wave number of 4000 to 400 cm ⁻¹ (wavelength 2.5 to 25.0 μm), and the intensity and wave number (wavelength) of infrared rays that pass through the specimen pellet. ). The measurement results are shown in FIG. In FIG. 22, the peak top of the transmittance on the vertical axis has a wave number of 799.74 cm ⁻¹ (12.5 μm) and a half width (half the height from transmittance 0% to the transmittance of the peak top). Only infrared rays having a peak width (90 cm ⁻¹ (1.36 μm)) are transmitted. For this reason, it turns out that the created test body is functioning as a filter which permeate | transmits infrared rays of a specific wavelength range.

Further, 0.0283 g of baked manganese carbonate powder, which is a precursor for obtaining a manganese dioxide nanoneedle porous body, is pulverized and mixed together with 0.4389 g of KBr powder in an agate mortar, and placed in a pressure molding jig. Was subjected to compression molding at a pressure of 4 MPa for 3 minutes to prepare a test specimen pellet having a diameter of 10 mm and a thickness of 0.5 mm (weight mixing ratio of calcined manganese carbonate and KBr was 1:15. 5. The concentration of the burned manganese carbonate in the test specimen pellet is 0.00606 wt%). The infrared transmission characteristics of this test specimen pellet are shown in FIG. In FIG. 23, since an infrared transmission component due to carbonate is observed, in the procedure for synthesizing the manganese dioxide nanoneedle porous body, it is possible to remove the carbonate component by performing sufficient acid treatment to obtain an infrared filter. It turns out that it is important for enhancing the characteristics. In addition, for the measurement of infrared transmission, a Fourier transform infrared spectroscopic analyzer Spectrum One Image System FT-IR Spectrometer manufactured by PerkinElmer was used.
<Example 13> Evaluation of infrared absorbing ability of infrared filter (2)
0.0280 g of manganese dioxide nanoneedle porous material having an average pore diameter of 18.68 nm, a BET specific surface area of 46.47 m ² / g, and a total pore volume of 0.22 cm ³ / g obtained in Example 2 was added to KB355 powder 0.4355 g. At the same time, it is pulverized and mixed in an agate bowl, placed in a pressure molding jig, compressed with a pressure of 4 MPa for 3 minutes while degassing with a rotary pump, and has a diameter of 10 mm and a thickness of 0.5 mm (plus or minus) 0.1 mm) specimen pellets were prepared. Therefore, the mixing weight ratio of the manganese dioxide nanoneedle porous material and KBr in this test specimen pellet is 1: 15.6. Moreover, the manganese dioxide nanoneedle porous body density | concentration is 6.04 wt%.

This specimen pellet is placed in an infrared spectrophotometer, irradiated with infrared rays having a wave number of 4000 to 400 cm ⁻¹ (wavelength 2.5 to 25.0 μm), and the intensity and wave number (wavelength) of infrared rays that pass through the specimen pellet. ). The measurement results are shown in FIG. In FIG. 24, the peak top of the transmittance on the vertical axis has a wave number of 810.92 cm ⁻¹ (12.3 μm) and a half-value width (half the height from the transmittance of 0% to the transmittance of the peak top). It transmits only infrared rays having a peak width of 100 cm ⁻¹ (1.49 μm). For this reason, it turns out that the created test body is functioning as a filter which permeate | transmits infrared rays of a specific wavelength range. Compared with FIG. 22 which is the result of Example 11, this example using a manganese dioxide nanoneedle porous body having a small specific surface area and a large average pore diameter is a transmission peak having a slightly wider half width, Since the value of the transmittance is high, it can be seen that the infrared transmittance in substantially the same wavelength region is higher than that of the test specimen pellet of Example 11.

Moreover, carbon materials such as graphite and activated carbon were added to KBr to prepare similar test specimen pellets, and the infrared transmission characteristics were confirmed by the same method. When carbon materials were added, 2.5 to It was confirmed that the filter effect as in the present invention could not be obtained because infrared absorption occurred over the entire wavelength region of 25 μm. In addition, for the measurement of infrared transmission, a Fourier transform infrared spectroscopic analyzer Spectrum One Image System FT-IR Spectrometer manufactured by PerkinElmer was used.
<Example 14>
The acid-treated paste synthesized in Example 3 above was evenly applied to a smooth cloth and then naturally dried. Prepare a paper cup (10cm in height and 6cm in diameter) containing hot water of about 50 ° C, and place this paper cup on the table 10mm in front of the paper cup. 1) Nothing 2) White cloth 3) A flat cloth coated with porous powder composed of manganese dioxide nanoneedles was set up and observed with an infrared monitor night vision (Honda Motor Legend 2005). The distance between the paper cup and the car equipped with the infrared sensor was set to 10 m.

As a result, in 1), a white paper cup clearly appears on the monitor. 2) A white paper cup appears. 3) You can see that there is something in the gray color, but it doesn't become white like 1) or 2). The result was obtained. From this result, it was found that the porous powder composed of manganese dioxide nanoneedles coated on the cloth absorbs and blocks infrared rays emitted from a paper cup containing hot water. Therefore, it has been proved that the material of the present invention exhibits an effective infrared absorber performance even when a highly reliable and highly sensitive infrared monitor incorporated in a commercial vehicle is used.
<Comparative example>
Commercially available manganese dioxide (special grade manganese oxide IV product manufactured by Wako Pure Chemical Industries), commercial manganese oxide (special grade manganese oxide III Mn ₂ O ₃ manufactured by Wako Pure Chemical Industries), commercial titanium oxide (special grade titanium oxide III manufactured by Wako Pure Chemical Industries, Ltd. III) TiO ₂ ) was crushed and mixed in an agate mortar under the conditions shown in Table 2, put into a pressure molding jig, and compressed and molded at a pressure of 4 MPa for 3 minutes while degassing with a rotary pump. A test specimen pellet having a thickness of 0.5 mm (plus / minus 0.1 mm) was prepared.

Next, each prepared specimen pellet is installed in an infrared spectrophotometer, and irradiated with infrared rays having a wave number of 4000 to 400 cm ⁻¹ (wavelength 2.5 to 25.0 μm) to transmit each specimen pellet. Infrared intensity and wave number (wavelength) were examined. The measurement results are shown in FIGS.

FIG. 25 shows the infrared transmission characteristics of a test specimen pellet in which commercially available manganese dioxide and KBr are mixed. This commercially available manganese dioxide (special grade manufactured by Wako Pure Chemical Industries, Ltd.) is a fine powder having a size of about 10 nanometers when observed with a transmission electron microscope. Therefore, when the nanoneedle porous body of manganese dioxide of the present invention is used 22 shows the transmission wavelength and transmission intensity similar to those of FIG. 22 and FIG. 24, but an infrared transmission peak based on adsorbed water containing commercially available manganese dioxide is observed in the wave number region of 1500 to 1000 cm ^−1. . This is because the commercially available manganese dioxide is simply an aggregate of fine particles, so that the irradiated infrared rays are diffusely reflected inside the material as in the case of using the manganese dioxide nanoneedle porous body of the present invention, and the intensity is increased. This is probably because the attenuation effect cannot be obtained. For this reason, it can be said that the manganese dioxide nanoneedle porous body of the present invention is superior as an additive for making an infrared filter.

Next, FIG. 26 shows the infrared transmission characteristic regarding the test body pellet which mixed commercially available manganese oxide (III) (the reagent 99% made from STREM CHEMICALS) and KBr. Compared to the commercially available manganese dioxide of FIG. 25, there is no transmission peak of adsorbed water in the wave number region of 1500 to 1000 cm ⁻¹ , but the intensity of incident infrared rays is high because the transmission intensity is more than 7 times higher and the half width is wider. In this case, it is expected that the filter characteristics will deteriorate as the half-value width increases.

  Moreover, FIG. 27 shows the infrared transmission characteristic regarding the test body pellet which mixed commercially available titanium oxide (IV) (the reagent special grade made from Wako Pure Chemical Industries) and KBr. The result of FIG. 27 is different from the case of FIG. 22 and FIG. 24 in which the manganese dioxide nanoneedle porous body of the present invention is used in that the transmission wavelength peak is seen at 9.2 μm. I understand that. However, since the transmission intensity is 6 to 10 times higher than that in FIGS. 22 and 24, when the energy of the incident infrared rays is high, it is expected that the filter characteristics will be deteriorated by widening the half width.

  In addition, the Fourier transform infrared spectroscopic analyzer Spectrum One Image System FT-IR Spectrometer manufactured by PerkinElmer was used for the above infrared transmission measurement.

Is a schematic view of the mechanism of the present hydrogenated synthetic manganese oxide HMnO _2. This is a result of irradiating hydrogenated manganese oxide and ice with neutrons. FIG. 2 schematically shows a network composed of an oxygen atom-oxygen atom having a bond distance of 2.589 Å (b direction) and an oxygen atom-oxygen atom of 2.573 Å (a direction) in the crystal structure of R-type manganese dioxide. It is a figure. 2 is a transmission electron microscope image of nanoneedle aggregates in Example 1. FIG. 2 is a transmission electron microscope image of a tip portion of a nanoneedle in Example 1. FIG. It is the surface analysis result by the nitrogen gas adsorption method of the nanoneedle aggregate in Example 1. 3 is a transmission electron microscope image of nanoneedle aggregates in Example 2. FIG. 3 is a transmission electron microscope image of another nanoneedle aggregate in Example 2. FIG. 4 is a transmission electron microscope image of a tip portion of a nanoneedle in Example 2. FIG. FIG. 9 is a high resolution photograph of FIG. 8. It is the surface analysis result by the nitrogen gas adsorption method of the nanoneedle aggregate in Example 2. 3 is an X-ray diffraction pattern of nanoneedle aggregates in Example 2. FIG. 6 is a transmission electron microscope image of nanoneedles in Example 3. FIG. 4 is a transmission electron microscope image of a tip portion of a nanoneedle in Example 3. FIG. 4 is an X-ray diffraction pattern of nanoneedle aggregates obtained when dilute hydrochloric acid having a water temperature of 14 ° C. is used for acid treatment in Example 4. 4 is an X-ray diffraction pattern of nanoneedle aggregates obtained when dilute hydrochloric acid having a water temperature of 35 ° C. is used for acid treatment in Example 4. FIG. It is a X-ray-diffraction analysis result of the paste in Example 7, and the R type manganese dioxide obtained by drying it. It is an analysis result of the manganese valence by the X-ray absorption edge analysis (XANES) of the paste in Example 7. 9 is a transmission electron microscope image of R-type manganese dioxide nanoneedles carrying metallic palladium nanoparticles in Example 8. FIG. 6 is a transmission electron microscope image of R-type manganese dioxide carrying metallic palladium nanoparticles in Example 8. FIG. It is a figure showing the infrared absorption characteristic of the manganese dioxide nanoneedle porous body in Example 11. It is a figure showing the infrared transmission characteristic of the manganese dioxide nanoneedle porous body in Example 12. It is a figure showing the infrared transmission characteristic of the baked manganese carbonate in Example 12. It is a figure showing the infrared absorption characteristic of the manganese dioxide nanoneedle porous body in Example 13. It is a figure showing the infrared transmission characteristic of the commercially available manganese dioxide in a comparative example. It is a figure showing the infrared transmission characteristic of commercial manganese oxide (III) in a comparative example. It is a figure showing the infrared transmission characteristic of the commercially available titanium oxide (IV) in a comparative example.

Claims (20)

It is composed of needle-shaped nanoneedles mainly composed of R-type manganese dioxide, and a mesoporous porous body structure in which a mesoporous porous structure is formed with these nanoneedles, wherein the mesoporous porous structure is Manganese dioxide nanoneedles having an average pore diameter of 3 nm to 30 nm, a BET specific surface area of 40 to 200 m ² / g, and a total pore volume of 0.1 to 0.5 cm ³ / g Porous body. It is composed of needle-shaped nanoneedles mainly composed of R-type manganese dioxide, and a mesoporous porous body structure in which a mesoporous porous structure is formed with these nanoneedles, wherein the mesoporous porous structure is Manganese dioxide nanoneedles having an average pore diameter of 7 nm to 14 nm, a BET specific surface area of 80 to 130 m ² / g, and a total pore volume of 0.2 to 0.5 cm ³ / g Porous body. It is composed of needle-shaped nanoneedles mainly composed of R-type manganese dioxide, and a mesoporous porous body structure in which a mesoporous porous structure is formed with these nanoneedles, wherein the mesoporous porous structure is Manganese dioxide nanoneedles having an average pore diameter of 15 nm to 30 nm, a BET specific surface area of 40 to 50 m ² / g, and a total pore volume of 0.1 to 0.3 cm ³ / g Porous body. 4. The manganese dioxide nanoneedle porous body according to claim 1, wherein the surface hardness is in the range of Vickers hardness of 15 to 35 as measured by a Vickers hardness test method . 5. A needle-shaped R-type manganese dioxide nanoneedle having a size of nanometer scale and mainly composed of R-type manganese dioxide, wherein the nanoneedle has a thickness of 1 to 100 nm and a length of 3 to 900 nm. An R-type manganese dioxide nanoneedle characterized by the above. A needle-shaped R-type manganese dioxide nanoneedle having a size of nanometer scale and mainly composed of R-type manganese dioxide, wherein the nanoneedle has a thickness of 2 to 10 nm and a length of 5 to 30 nm. An R-type manganese dioxide nanoneedle characterized by the above . A needle-shaped R-type manganese dioxide nanoneedle having a size of nanometer scale and mainly composed of R-type manganese dioxide, wherein the nanoneedle has a thickness of 10 to 30 nm and a length of 30 to 300 nm. An R-type manganese dioxide nanoneedle characterized by the above . A metal-supported R-type manganese dioxide nanoneedle, wherein a metal is supported on the R-type manganese dioxide nanoneedle according to claim 5. 9. The metal-supported R-type manganese dioxide nanoneedle according to claim 8, wherein the supported metal is gold or palladium. R-type manganese dioxide MnO ₂ In the crystal structure of ⁺ And e ⁻ Impregnated manganese valence + tetravalent hydrogenated manganese oxide HMnO ₂ The hydrogenated manganese oxide HMnO is characterized in that the nanoparticle has a thickness of 2 to 10 nm, a length of 5 to 30 nm and a needle shape. ₂ Nano particles. R-type manganese dioxide MnO ₂ In the crystal structure of ⁺ And e ⁻ Impregnated manganese valence + tetravalent hydrogenated manganese oxide HMnO ₂ The hydrogenated manganese oxide HMnO is characterized in that the nanoparticle has a thickness of 10 to 30 nm, a length of 30 to 300 nm, and a needle shape. ₂ Nano particles. A mesoporous material made of the manganese dioxide nanoneedle porous material according to any one of claims 1 to 4. 13. The mesoporous material according to claim 12, wherein the mesoporous material is a film-like body. It is a manufacturing method of the manganese dioxide nanoneedle porous body of Claim 1, Comprising: Manganese carbonate n-hydrate MnCO ₃ ・ NH ₂ A method for producing a manganese dioxide nanoneedle porous body, which comprises firing O powder, treating it with an acid to form a paste, and then drying the paste. The method for producing a manganese dioxide nanoneedle porous body according to claim 14, wherein bismuth carbonate carbonate is mixed with manganese carbonate n-hydrate and baked. The method for producing a manganese dioxide nanoneedle porous body according to claim 14 or 15, wherein the acid treatment is performed at least twice. Hydrogenated manganese oxide HMnO, characterized by acid-treating the R-type manganese dioxide nanoneedles according to any one of claims 5 to 7 ₂ Of producing nano-particles. An infrared-absorbing material comprising the porous manganese dioxide nanoneedle according to claim 1. An infrared filter comprising the infrared absorbing material according to claim 18. The infrared filter according to claim 19, wherein the transmitted infrared light has a wavelength range of 10 to 14 μm.