JP2009119423A - Active b-c-n material and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a B-C-N material as an adsorbent for adsorption-removal of a harmful substance, in particular, cleaning of an exhaust gas, although the material is not considerted heretofore as an adsorbent. <P>SOLUTION: The active B-C-N material comprises carbon, nitrogen and boron. In the active B-C-N material, a specific surface area is 100-3,000 m<SP>2</SP>/g, an average thin pore diameter is 0.4-50 nm, and the oxygen content of the B-C-N material is 1-20 mass%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an active B—C—N material composed of carbon, nitrogen, and boron, and a method for producing the same, and more specifically, for adsorbing and removing air pollutants and water pollutants, particularly in exhaust gas. The present invention relates to an active B—C—N material for efficiently adsorbing and removing harmful substances and a method for producing the same.

Conventionally, exhaust gas emitted from diesel vehicles has a high oxygen concentration and a relatively low content of reducing hydrocarbons such as propylene compared to the NOx content (usually the oxygen concentration is 10% or more, An exhaust gas having an oxygen concentration of 1% or more is called a lean burn exhaust gas), and even a platinum catalyst having a high ability to oxidize NO to NO ₂ has a very low NOx purification rate. Therefore, a NOx absorbent is added to the catalyst, and NOx contained in the exhaust gas is supplementarily absorbed and removed. For example, alkali metals and alkaline earth metals disclosed in Patent Document 1 are used. In general, a NOx occlusion reduction type catalyst containing a basic substance consisting of is used. However, since these basic NOx absorbents easily combine with the acidic oxides of NOx and SOx, there is a problem that the absorption capacity is lowered over time. In order to restore the absorption capacity, a calcination regeneration treatment at a high temperature (usually 750 ° C. or higher) has been proposed, but it is not preferable because aging of catalyst active components such as platinum (thermal aging of catalyst performance) occurs. In addition, catalyst materials for efficiently purifying low-temperature exhaust gas (typically 120 ° C to 200 ° C) during transient running emitted by diesel vehicles are still undeveloped, so the development of excellent new materials is expected. ing.
The specific surface area of activated carbon is usually 1000 m ² / g or more, has a large adsorbing power, and has many kinds of adsorption sites. Conventional adsorbents for adsorbing and removing air pollutants and water pollutants have been used. It is used as However, since it is a flammable substance, it is usually used for the purpose of adsorption removal of harmful substances such as NOx, SOx, hydrocarbons, PM (particulates) contained in exhaust gas discharged from internal combustion engines such as automobiles. Absent.

On the other hand, around 1970, a heat-resistant graphite-like structure B-C-N (referred to as boron carbon nitride or solid solution of carbon and boron nitride) made of carbon, nitrogen and boron was used in Russia. This result was reported in Non-Patent Document 1. Since then, many types of B—C—N materials have been developed for purposes such as high hardness materials and their precursors, lithium battery electrode materials, semiconductor materials, and the like. B-C-N materials are roughly classified into graphite-like structures and cubic structures. A graphite-like structure is, for example, a method in which a vapor of a nitrogen-containing organic substance such as amine or nitrile and a boron halide gas are reacted in a high-temperature zone under an inert air flow as disclosed in Patent Document 2 (thermal CVD). Method), a method (chemical reaction method) in which nitrogen-containing organic substances such as amines and nitrites such as those disclosed in Patent Document 3 are reacted with boron halides under an inert gas stream, and disclosed in Patent Document 4 A method in which a volatile organic substance, nitrogen gas, and diborane are reacted by a plasma CVD method (plasma CVD method), and a carbon source, a nitrogen source, and a boron source as disclosed in Patent Document 5 are heated at high frequency A thin film-like boron carbonitride on the substrate (high-frequency heating method), high temperature and high pressure treatment of carbon and boron nitride as disclosed in Patent Document 6 That method (high-temperature high-pressure method), has been reported to be produced by such. It has been reported that the cubic structure is produced, for example, by impact compression of a B—C—N material having a graphite-like structure as disclosed in Patent Document 7 (impact compression method). Further, as a graphite-like structure BCN material, for example, a material having improved heat resistance as compared with graphite as disclosed in Non-Patent Document 2 is also known. However, in general, these graphite-like B-C-N materials and cubic B-C-N materials specific surface area very small (typically a few ^m 2 / g to speed ^{10 m} 2 / g or so), adsorption Since the force is very small, it is hardly expected to be used as an adsorbent such as activated carbon. Therefore, it is almost difficult to use it as an adsorbent removal agent for automobile exhaust gas purification as described above.

Recently, as disclosed in Patent Document 8, a mixture of mesoporous carbon and a boron raw material such as boron oxide, boron, or B ₄ C is heated by heating at 1300-1800 ° C. in a nitrogen stream. A method for producing boron carbonitride materials has been reported. However, as reported in Non-Patent Document 1 above, direct synthesis from carbon, boron, and nitrogen is optimal under heating conditions at 1800-2000 ° C., and B—C—N materials at temperatures below this temperature. In addition, since carbon and B ₄ C are described as by-products, there remains a question that the material produced by the method of Patent Document 8 is a single substance in which carbon, nitrogen, and boron are combined. In any case, the material produced by the method of Patent Document 8 is presumed to have a large surface area and a large number of pores, but it is not a production method for generating a functional group that exhibits an adsorptive power. Therefore, the material produced by this method is hardly expected to be used as an adsorbent.

Japanese National Patent Publication No. 06-509374 Japanese Patent Laid-Open No. 06-219730 Japanese Patent Laid-Open No. 2003-081615 JP 2002-293516 A JP 2002-19597 A JP 04-161240 A Japanese Patent Laid-Open No. 06-316411 JP 2007-031170 A Poroshkovaya Metallurgiya, 1971, 1, 27-33. J. Chem. Soc., Faraday Trans., 1996, 92 (24), 5067-5071.

  In view of the above circumstances, the present invention is an active BC for efficiently adsorbing and removing air pollutants and water pollutants, particularly for efficiently adsorbing and removing harmful substances contained in automobile exhaust gas. -N material and its manufacturing method.

As a result of intensive studies to achieve the above object, the present inventors have found that the activated BCN material is very effective in removing harmful substances such as NOx in exhaust gas. As a result, the present invention has been completed based on this finding.
That is, the present invention
(1) An active B—C—N material composed of carbon, nitrogen, and boron, having a specific surface area of 100 to 3000 m ² / g, an average pore diameter of 0.4 to 50 nm, and an oxygen content of 1 to 20 Active B—C—N material, characterized in that it is by weight,
(2) The production of an active BCN material as described in (1) above, wherein a BCN material having a specific surface area of 0.1 to 50 m ² / g is activated with an oxidizing agent. Method,
(3) The method for producing an active BCN material as described in (2) above, wherein the oxidizing agent is a strongly basic substance,
(4) The method for producing an active B—C—N material according to (2), wherein the oxidizing agent is an oxo acid or an oxo acid salt;
(5) The method for producing an active BCN material as described in (2) above, wherein the oxidizing agent is supercritical water;
(6) An exhaust gas purification method characterized by using the active B—C—N material described in (1) above for exhaust gas purification.

  By using the active B—C—N material of the present invention for exhaust gas purification, the lean burn exhaust NOx, which has been difficult to purify so far, can be purified extremely efficiently from the low temperature region to the intermediate temperature region. For example, a NOx occlusion reduction type catalyst containing an alkaline earth metal oxide (NOx occlusion agent) as a catalyst when a nitrogen monoxide-containing harmful gas having an oxygen concentration of 10% is purified on the catalyst using propylene as a reducing agent. Is used, the reaction starts at around 250 ° C. and the NOx purification rate is about 40% at the maximum, but in the case of a platinum catalyst containing the activated boron carbonitride material of the present invention as a NOx adsorbent, it is 150 ° C. The reaction starts from the vicinity, and a NOx purification rate of 90% or more can be achieved in a wide temperature range of 160 ° C to 400 ° C.

Hereinafter, the present invention will be described in detail.
The B—C—N material in the present invention is a boron carbide nitride material composed of carbon atoms, boron atoms, and nitrogen atoms. Each atom is bonded to each other by chemical bonds, also known as a solid solution of carbon and boron nitride. It is a single substance formed by combining carbon, nitrogen, and boron, and is different from a mixture of carbon and boron nitride.
The composition ratio x: y: z in the chemical formula BxCyNz of the B—C—N material is not particularly limited. The boron atom to be contained is an important component for improving the heat oxidation resistance of the material. The nitrogen atom is an important component for fixing the boron atom as boron nitride. A carbon atom and a nitrogen atom are important components for forming an adsorption active site. Therefore, although the composition ratio x: y: z is not specified in the present invention, boron carbonitride such that y = (0.1-100) x and x≈Z from the viewpoint of adsorption performance and durability. It has been found that materials are preferred, and boron carbonitride materials such that y = (1-20) x and x≈z are more preferred. Even when the carbon component ratio exceeds 100 times that of boron or nitrogen, it has a high adsorption performance, but since the heat resistance approaches the properties of activated carbon, it is preferably 100 times or less. Further, when the carbon component ratio is less than one-tenth of boron or nitrogen, the property of the adsorption site is changed from hydrophilic to oleophilic, so that it is preferably at least one-tenth.

Since the active BCN material of the present invention is produced by subjecting a normal BCN material having poor adsorptivity to an activation treatment, the physical properties of the BCN material used (for example, the ratio) The activation process is possible regardless of the surface area or crystal structure), but the properties common to B—C—N materials with poor adsorptivity are that there are almost no surface functional groups and no pores. Such B—C—N materials are subject to activation treatment because they are not substantially present or very little, if any. The amount of pores is also directly related to the specific surface area, and the small number of pores means that the specific surface area is small. Conventionally, knowledge about the specific surface area of the B—C—N material is very small. Therefore, when approximate values are estimated, the film-like material is in the range of 0.1 to ¹ m ² / g, and the particulate material is 1 It is estimated to be in the range of ˜50 m ² / g. Therefore, the specific surface area of the B—C—N material used as a raw material in the present invention is usually in the range of 0.1 to 50 m ² / g, but in general, a particulate material rather than a thin film material. Since it is more productive to activate the material, the preferred specific surface area is 1 to 50 m ² / g. In addition, the quantitative measure of pores can be generally expressed by pore volume. Although it is difficult to accurately express that the pores are substantially absent or very few, if any, most conventional B—C—N materials with poor adsorptivity have their fine details. The pore volume is 0.1 cm ³ / g or less.

The B—C—N material used as a raw material in the present invention can be produced by the production methods described in Patent Documents 2 to 8 as described in [Background Art]. BCN materials produced by these methods usually have a graphite-like structure (generic name such as a graphite structure or a turbostratic structure that is less symmetrical in the c-axis direction than the graphite structure) or a clear X-ray diffraction pattern. It has an amorphous material that does not have, and a dense cubic structure. However, in general, the conventional B—C—N material does not have a function as an adsorbent because of a small specific surface area, few pores, few functional groups for adsorption, and the like. The active B—C—N material of the present invention uses such a poor B—C—N material as a raw material. In order to produce the active B—C—N material of the present invention, a graphite-like structure or an amorphous B—C—N material that is relatively easy to activate and can be mass-produced is preferred.
The specific surface area of this invention active BCN material obtained by an activation process is 100-3000 m < ² > / g normally, Preferably it is 200-1000 m < ² > / g. If it is less than 100 m ² / g, the adsorption performance is insufficient, and therefore it is preferably 100 m ² / g or more, and if it exceeds 3000 m ² / g, the mechanical durability is greatly reduced, so that it is 3000 m ² / g or less. It is preferable that

The active B—C—N material of the present invention not only has a specific surface area increased by the activation treatment, but also contains a large amount of fine pores and hydrophilic functional groups. The pore distribution of pores newly generated by the activation treatment is usually preferably in the range of 0.4 nm to 50 nm, more preferably in the range of 0.6 nm to 20 nm, and most preferably in the range of 0.8 nm to 3 nm. If it is less than 0.4 nm, the diffusion of the substance to be adsorbed in the pores is insufficient, so that it is preferably 0.4 nm or more. preferable. Moreover, the hydrophilic functional group newly generated by the activation treatment is a hydroxyl group (OH), an alcoholic hydroxyl group (ROH), a carbonyl group (CO), a carboxyl group (CO ₂ H), an amino group (NH ₂ ), or the like. In general, the total concentration of these functional groups is preferably in the range of 1 to 20% by mass and more preferably in the range of 5 to 15% by mass in terms of oxygen content per B—C—N material. preferable. If it is less than 1% by mass, the adsorption performance is insufficient, so that it is preferably 1% by mass or more, and if it exceeds 20% by mass, the mechanical durability decreases greatly, so it is 20% by mass or less. It is preferable.

The active B—C—N material of the present invention is produced by activation treatment using a boron carbonitride material having a small specific surface area as a raw material as described above. It is preferable to use an oxidizing agent as the agent used for the activation treatment in order to form a surface functional group for adsorbing harmful substances. As the oxidizing agent, strong basic substances, oxo acids, oxo acid salts, supercritical water, halogen, hydrogen peroxide, ozone, nitrogen dioxide, sulfur dioxide, sulfur trioxide, phosphorus pentoxide, vanadium pentoxide, etc. are used. Among these, strong basic substances, oxoacids, oxoacid salts, and supercritical water are preferable from the viewpoint of oxidizing power and handleability. Strongly basic substances include alkali metals, alkali metal hydroxides, alkali metal oxides, alkali metal peroxides, alkali metal superoxides, alkali metal nitrates, alkaline earth metals, alkaline earths Metal hydroxides, alkaline earth metal peroxides, alkaline earth metal superoxides, alkaline earth metal nitrates, etc. are preferred, among which alkali metal hydroxides and alkaline earth metal water Oxides are more preferred because they are basic and easy to handle. As oxo acid and oxo acid salt, nitric acid, sulfuric acid, phosphoric acid, aqua regia, mixed acid (mixed solution of sulfuric acid and nitric acid), perchloric acid, perchlorate, hypohalous acid, hypohalous acid salt, iron acid Salts, heteropolyacids, heteropolyacid salts, and permanganates are more preferable because they have high oxidizing power and are relatively easy to handle. The supercritical water in the present invention is a water molecule in a state exceeding the critical constant. As for the critical constant of water, the critical temperature is Tc = 647.3K and the critical pressure is Pc = 22.22 MPa. Therefore, in this temperature-pressure state, the water molecules are in phase equilibrium between the liquid and gas phases. Moreover, 500 degreeC or more and 36.65 Mpa or more are usually called a supercritical state, and since radical decomposition | disassembly of a water molecule has arisen, very strong oxidation property is shown. The supercritical water in the present invention refers to water in such a supercritical state.
Activation treatment with a strongly basic substance not only oxidizes the carbon atoms contained in the B—C—N material to alcohol groups (ROH), carbonyl groups (CO), carboxyl groups (CO ₂ H), etc., but also nitrogen atoms Is converted to an amino group which is a basic functional group. The activation treatment with an oxo acid and an oxo acid salt is characterized by generating a hydroxyl group and oxidizing a carbon atom contained in the boron carbonitride material to a carbonyl group (CO), a carboxyl group (CO ₂ H), or the like. In addition, the activation treatment with supercritical water is characterized in that a hydroxyl group is newly generated.

  The activation treatment using the above drugs (excluding supercritical water) is usually performed by adding a B—C—N material as a raw material to an aqueous solution of the drug at a temperature ranging from room temperature to the boiling point of the aqueous solution. Although it is possible to perform the treatment for a period of time, it is also possible to carry out the treatment in the range of room temperature to 500 ° C. for several tens of minutes to several hundreds of hours using a molten chemical or a gaseous chemical. The activation treatment conditions such as the heating temperature and treatment time of the activation treatment must be appropriately adjusted according to the oxidizing power of the oxidizing agent used. For example, when a strongly basic alkali hydroxide is used, the specific surface area of the active B—C—N material obtained when activated in an aqueous solution and at a temperature above the melting point, This is because the pore size, the amount of functional groups generated, and the B / C / N composition ratio may differ greatly. Normally, the treatment time is longer under mild conditions, but the B / C / N composition ratio can be activated without changing much from the composition ratio of the raw material, but under severe conditions, activation can be performed in a short time. However, the mass loss of the material is significant and the nitrogen and boron contents are significantly reduced. The case of using oxo acid, oxo acid salt, or supercritical water is basically the same as that of a strongly basic substance.

Among the above-mentioned activation treatment with a strong basic substance, activation treatment with an oxo acid or oxo acid salt, and activation treatment with supercritical water, the activation treatment with a strong basic substance increases the specific surface area, the pore size distribution, and This is the most preferable method because it is moderately harmonized in the generation of functional groups.
In the above activation treatment, oxygen-containing functional groups, amino groups, and the like are newly introduced. After performing the activation treatment described above in order to adjust the oxygen content or the amino group content, Reduction treatment can also be performed using a reducing agent. Such a reduction treatment can be performed in a gas stream using hydrogen, hydrazine, ammonia, etc. or in a solution using sodium borohydride, lithium aluminum hydride, hydrogen peroxide, thiosulfate, etc. Reduction can be performed.
The active B—C—N material of the present invention is much better in oxidation resistance than activated carbon, like the B—C—N material that is the raw material, and even when heated to 400 ° C. or higher in air, There is no complete combustion, and the mass reduction starts from around 600 ° C., but the mass reduction almost stops at around 800 ° C., and the mass is maintained at about 60% even at 1200 ° C. Therefore, it can be used as an adsorbing material for purifying automobile exhaust gas, which has heretofore been difficult to use.

The active B—C—N material of the present invention is suitable for efficiently adsorbing and removing harmful substances such as NOx and SOx in exhaust gas from a low temperature region to a medium temperature region. When used for purification of automobile exhaust gas, the active BCN material material of the present invention and an oxidation catalyst such as platinum are usually used in combination. The reason for this is to catalytically rotate the adsorption / desorption cycle with the active B—C—N material. Since the adsorption rate of the adsorbed substance depends on the concentration difference between the adsorbed substance concentration in the gas phase and the adsorbed substance adsorbed on the active BCN material, the adsorbed substance adsorbs on the active BCN material. It is important to quickly remove the adsorbed substances, and for that purpose, the adsorbed substances adsorbed by the active B—C—N material should be reduced and removed with a reducing substance on the catalyst.
As an oxidation catalyst such as platinum, a conventional platinum-rhodium catalyst supported on γ-alumina can be used, but platinum or the like is used as a mesoporous material having a very large specific surface area and an average pore diameter of 2 to 50 nm in a meso region. A catalyst supporting bismuth is preferred because it gives better results. Among them, a catalyst in which platinum or the like is supported on an amorphous mesoporous silica material having a specific surface area of 400 to 2000 m ² / g and an average pore diameter of several nanometers (which means that the pore arrangement is not regular) is very Is preferable because it gives good results.

In the case where the powder of the present invention active B—C—N material is filled in an exhaust gas purification tank and used, it can be used by mixing with a powder of an oxidation catalyst such as a platinum catalyst. When the N material is applied to a honeycomb support for automobiles, it is preferable to apply an oxidation catalyst such as a platinum catalyst on the honeycomb support after applying the active B—C—N material of the present invention to the honeycomb support. (This is called a double wash coat). The reason is that when the uniform mixed slurry in which the active BCN material and the oxidation catalyst of the present invention are mixed is applied to the honeycomb support, the surface of the oxidation catalyst is partially covered with the active BCN material. This is to prevent the catalyst performance from being impaired. The coating layer of the double wash coat is composed of at least two layers. An oxidation catalyst such as a platinum catalyst is provided in the uppermost layer (a layer in direct contact with the exhaust gas), and the coating layer of the present active BCN material is provided in the lower layer. The reason for this is to oxidize nitric oxide in the exhaust gas to NO ₂ in the uppermost layer, and to adsorb the produced NO ₂ with the lower active B—C—N material of the present invention. Part of the adsorbed NO ₂ is reduced by the adsorbed hydrocarbon, and part of it is desorbed and reduced by the hydrocarbon on the upper oxidation catalyst.
In addition, when the active BCN material of the present invention is used in combination with a catalyst used in the urea SCR method for purifying exhaust gas from trucks and buses, NOx purification starts from around 100 ° C. It is also very preferable as a vehicle exhaust gas purifier.

The present invention will be specifically described below with reference to examples.
The X-ray diffraction patterns in the examples were measured using an X-ray diffractometer (manufactured by Rigaku Corporation: RINT-UltimaIII). Specific surface area, pore volume, and pore distribution were measured with a Sorpmatic 1800 type apparatus manufactured by Carlo Elba using nitrogen as a desorption gas. The specific surface area and pore volume were determined by the BET method. The pore distribution was measured in the range of 0.4 to 200 nm and indicated by a differential distribution obtained by the BJH method. The pore distribution curve draws an exponentially upward distribution, and when a peak is shown at a specific pore diameter position, the pore diameter that gives this peak was taken as the average pore diameter. The functional group was measured with an infrared absorption spectrum measuring apparatus (JASCO FT-IR460). Elemental analysis was performed using an elemental analyzer (manufactured by PerkinElmer, Inc .: 2400II CHNS / O elemental analyzer). The analysis of boron was measured using an ICP-MS analyzer (VG-Elemental Plasmatrace ICP-mass Analyzer). A mixed gas of nitric oxide (NO) -oxygen (O ₂ ) -propylene (C ₃ H ₆ ) diluted with helium was used as a model gas for the exhaust gas. The NOx treatment rate is determined by measuring the NOx contained in the treated gas with a reduced pressure chemiluminescence NOx analyzer (manufactured by Nippon Thermo Co., Ltd .: models 42i-HL and 46C-H), and the following formula (1) Calculated by The NOx concentration is the sum of the concentration of nitric oxide and the concentration of nitrogen dioxide.
[Equation 1]
{1- (NOx concentration contained in gas after reaction / NOx concentration contained in gas before reaction)} × 100 (%) (1)

[Production Example 1] Production of BC ₂ N material 50 g of melamine was placed in a quartz three-necked flask and heated to 200 ° C. Boron trichloride gas was introduced into this, and the reaction was continued until the absorption of boron trichloride gas was stopped. After completion of the reaction, the inside of the flask was replaced with nitrogen gas, the temperature was raised to 500 ° C. while flowing nitrogen gas, and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, this intermediate product was transferred to an alumina crucible, placed in an electric furnace, heated to 1500 ° C. under a nitrogen stream, and heated at this temperature for 2 hours. The product was taken out after standing_to_cool to room temperature. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen≈1: 1: 1. Infrared absorption spectrum showed a weak peak at strong peak at 1400 cm ^-1 (attributed to the hetero ring stretching vibration) and 794cm ^-1 (attributed to the heterocyclic deformation vibration). As a result of X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.245 nm and c ₀ = 0.696 nm. The specific surface area was 15 m ² / g, the pore volume was 0.06 cm ³ / g, and the pore distribution curve rising to the left showed very small peaks at positions of about 4 nm and about 80 nm. From these results, it was confirmed that the product was a graphite-like BC ₂ N material having a small specific surface area and almost no pores.

“Production Example 2” Production of BC ₂ N Material 50 g of acetonitrile liquid was placed in a quartz three-necked flask, boron trichloride gas was introduced into the flask, and the reaction was continued until absorption of boron trichloride gas was stopped. After completion of the reaction, the inside of the flask was replaced with nitrogen gas, the temperature was raised to 500 ° C. while flowing nitrogen gas, and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, this intermediate product was transferred to an alumina crucible, placed in an electric furnace, heated to 1500 ° C. under a nitrogen stream, and heated at this temperature for 2 hours. The product was taken out after standing_to_cool to room temperature. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen≈1: 2: 1. Infrared absorption spectrum showed a weak peak at strong peak and 794cm ^-1 to 1387cm ^-1. As a result of X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.682 nm. The specific surface area was 18 m ² / g, the pore volume was 0.07 cm ³ / g, and the pore distribution curve rising to the left showed very small peaks at about 4 nm and about 80 nm. From these results, it was confirmed that the product was a graphite-like BC ₂ N material having a small specific surface area and almost no pores.

“Production Example 3” Production of BC ₅ N material A quartz three-necked flask was charged with 50 g of polyacrylonitrile (Asahi Kasei product: homopolymer of acrylonitrile having a molecular weight of about 10,000), and boron trichloride gas was introduced into it. The reaction was continued until the absorption of boron trichloride gas stopped. After completion of the reaction, the inside of the flask was replaced with nitrogen gas, the temperature was raised to 500 ° C. while flowing nitrogen gas, and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, this intermediate product was transferred to an alumina crucible, placed in an electric furnace, heated to 1500 ° C. under a nitrogen stream, and heated at this temperature for 2 hours. The product was taken out after standing_to_cool to room temperature. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen≈1: 5: 1. Infrared absorption spectrum showed a weak peak at strong peak and 794cm ^-1 to 1400 cm ^-1. As a result of X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.242 nm and c ₀ = 0.676 nm. The specific surface area was 17 m ² / g, the pore volume was 0.07 cm ³ / g, and the pore distribution curve rising to the left showed very small peaks at about 4 nm and about 80 nm. From these results, it was confirmed that the product was a graphite-like BC ₅ N material having a small specific surface area and almost no pores.

And heated to "Production Example 4" _{BC 10} N 100 ° C. was placed in a three-necked flask 1,10 diaminodecane 50g steel manufacturing quartz material. Boron trichloride gas was introduced into this, and the reaction was continued until the absorption of boron trichloride gas was stopped. After completion of the reaction, the inside of the flask was replaced with nitrogen gas, the temperature was raised to 500 ° C. while flowing nitrogen gas, and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, this intermediate product was transferred to an alumina crucible, placed in an electric furnace, heated to 1500 ° C. under a nitrogen stream, and heated at this temperature for 2 hours. The product was taken out after standing_to_cool to room temperature. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen≈1: 10: 1. Infrared absorption spectrum showed a weak peak at strong peak and 794cm ^-1 to 1400 cm ^-1. As a result of X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.670 nm. The specific surface area was 16 m ² / g, the pore volume was 0.06 cm ³ / g, and the pore distribution curve rising to the left showed very small peaks at about 4 nm and about 80 nm. From these results, it was confirmed that the product was a graphite-like BC ₁₀ N material having a small specific surface area and almost no pores.

“Production Example 5” Production of active BC ₂ N material by activation treatment with alkaline aqueous solution 10 g of the powder of BC ₂ N material of Production Example 1 was put in a beaker, and 100 g of 50% by mass potassium hydroxide aqueous solution was added thereto. Boiled for 2 hours. After allowing to cool to room temperature, 1 liter of distilled water was added thereto, and the stirred solution was filtered under reduced pressure. The filtrate was sufficiently washed with water until the filtrate became almost neutral, and then dried in vacuo at 120 ° C. for 5 hours. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen: hydrogen: oxygen≈1: 2: 1: 0.2: 0.2, and the oxygen content was about 6 mass%. The infrared absorption spectrum shows a broad weak peak near 1560 cm ⁻¹ (attributed to C = C stretching vibration and C═O stretching vibration), and a broad medium peak near 1400 cm ⁻¹ (in the heterocyclic stretching vibration). attributed), attributed to the peak (C-O stretching vibration of medium broad around of 1020 cm ^-1), showed a weak peak at 795 cm ^-1 (attributed to the heterocyclic deformation vibration). As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.682 nm. The specific surface area was 120 m ² / g, the pore volume was 0.12 cm ³ / g, and the average pore diameter was 2.4 nm. From these results, it was found that the product was an active BC ₂ N material.

“Production Example 6” Production of activated BC ₆ N material by activation treatment under molten alkali conditions 10 g of the powder of BC ₂ N material of Production Example 1 is put in a porcelain dish, and 20 g of 50% by weight aqueous potassium hydroxide solution is added thereto. After evaporating to dryness, the temperature was raised to about 400 ° C. and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, 1 liter of distilled water was added thereto, and the dispersion in which the solid was dispersed was filtered under reduced pressure, washed thoroughly with water until the filtrate was almost neutral, and then vacuum dried at 120 ° C. for 5 hours. did. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen: hydrogen: oxygen≈1: 6: 1: 3: 0.6, and the oxygen content was about 8% by mass. Infrared absorption spectrum (attributed to C-H stretching vibration) very small peak at 2920 cm ^-1 and 2950 cm ^-1, a broad weak peak near 1560 cm ^-1, a broad weak peak near 1400 cm ^-1, A broad medium peak was observed around 1020 cm ⁻¹ . As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.682 nm. The specific surface area was 430 m ² / g, the pore volume was 0.36 cm ³ / g, and the average pore diameter was 1.0 nm. These results showed that the product was an active BC ₆ N material.

“Production Example 7” Production of activated BC ₁₂ N material by activation treatment under molten alkaline conditions 10 g of the powder of BC ₂ N material of Production Example 2 is put in a porcelain dish, and 20 g of 50% by mass aqueous potassium hydroxide solution is added thereto. After evaporating to dryness, the temperature was raised to about 400 ° C. and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, a dispersion obtained by adding 100 times the amount of distilled water thereto was filtered under reduced pressure, sufficiently washed with water until the filtrate became almost neutral, and then vacuum-dried at 120 ° C. for 5 hours. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen: hydrogen: oxygen≈1: 12: 1: 6: 1, and the oxygen content was about 8% by mass. Infrared absorption spectrum, a very small peak at 2920 cm ^-1 and 2950 cm ^-1, a broad weak peak near 1560 cm ^-1, a broad weak peak near 1400 cm ^-1, a peak of moderate broad in of 1020 cm ^-1 Indicated. As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.242 nm and c ₀ = 0.711 nm. The specific surface area was 330 m ² / g, the pore volume was 0.28 cm ³ / g, and the average pore diameter was 0.8 nm. These results indicated that the product was an active BC ₁₂ N material.

[Production Example 8] Production of activated BC ₂₀ N material by activation treatment under molten alkali conditions 10 g of the powder of BC ₅ N material of Production Example 3 is placed in a porcelain dish, and 20 g of a 50% by mass aqueous potassium hydroxide solution is added thereto. After evaporating to dryness, the temperature was raised to about 400 ° C. and heating was continued at this temperature for 1 hour. After allowing to cool to room temperature, a dispersion obtained by adding 100 times the amount of distilled water thereto was filtered under reduced pressure, sufficiently washed with water until the filtrate became almost neutral, and then vacuum-dried at 120 ° C. for 5 hours. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen: hydrogen: oxygen≈1: 20: 8: 2, and the oxygen content was about 10% by mass. Infrared absorption spectrum, a very small peak at 2920 cm ^-1 and 2950 cm ^-1, (attributable to C = C stretching vibration and C = O stretching vibration) broad weak peak near 1580 cm ^-1, 1400 cm around ^-1 A broad weak peak was observed at 1020 cm ⁻¹ . As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.720 nm. The specific surface area was 650 m ² / g, the pore volume was 0.48 cm ³ / g, and the average pore diameter was 1.0 nm. These results indicated that the product was an active BC ₂₀ N material.

“Production Example 9” Production of Active BC ₂₀ N Material by Activation Treatment Using Oxo Acid 200 g of mixed acid (mixed solution of concentrated sulfuric acid: concentrated nitric acid = 8: 2) was placed in a beaker. 10 g of powder of BC ₂ N material was added and stirred at room temperature for 1 hour. After diluting with 2 liters of distilled water, the solid was filtered off with a glass filter. The solid was placed in 100 g of a 10% aqueous sodium hydrogen carbonate solution, the precipitate was filtered off with a glass filter, thoroughly washed with distilled water until the filtrate was almost neutral, and then dried in vacuo at 120 ° C. for 5 hours. . As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen: hydrogen: oxygen≈1: 20: 1: 10: 3, and the oxygen content was about 15% by mass. Infrared absorption spectrum (attributed to the stretching vibration of the carboxyl group) broad weak peak near 1732 cm ^-1, and a peak moderate broad around 1600 cm ^-1 (C = C stretching vibration and C = O attributed to stretching vibration). As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.730 nm. The specific surface area was 820 m ² / g, the pore volume was 0.70 cm ³ / g, and the average pore diameter was 1.0 nm. These results indicated that the product was an active BC ₂₀ N material.

“Production Example 10” Production of active BC ₁₆ N material by activation treatment using oxo acid salt 200 g of 20% by weight aqueous sodium hypochlorite aqueous solution was placed in a beaker, and the powder of BC ₁₀ N material of Production Example 4 was added thereto. 10 g was added and boiled for 1 hour. The solid matter was separated by filtration with a glass filter, washed with 100 g of a 10% by mass aqueous sodium hydrogen carbonate solution, sufficiently washed with distilled water until the filtrate became almost neutral, and then vacuum-dried at 120 ° C. for 5 hours. . As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen: hydrogen: oxygen≈1: 16: 1: 1: 1, and the oxygen content was about 7% by mass. Infrared absorption spectrum (attributed to C = C stretching vibration and C = O stretching vibration) broad weak peak near 1590 cm ^-1, a peak of moderate broad near 1400 cm ^-1, broad in of 1020 cm ^-1 Weak peak and a small peak at 795 cm ⁻¹ . As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.682 nm. The specific surface area was 210 m ² / g, the pore volume was 0.18 cm ³ / g, and the average pore diameter was 1.0 nm. These results indicated that the product was an active BC ₁₆ N material.

[Production Example 11] Production of activated BC ₂₀ N material by activation treatment using supercritical water 10 g of the powder of BC ₂ N material of Production Example 1 is put in an iron pressure vessel, 100 g of distilled water is added, and after sealing And placed in an electric furnace and heated at 500 ° C. for 5 hours. After cooling to room temperature, the contents were taken out, filtered under reduced pressure, washed with distilled water, and then vacuum dried at 120 ° C. for 5 hours. As a result of elemental analysis, the composition ratio was boron: carbon: nitrogen≈1: 20: 1: 10: 4, and the oxygen content was about 19% by mass. Infrared absorption spectrum, a very small peak at 2920 cm ^-1 and 2950 cm ^-1, (attributable to C = C stretching vibration and C = O stretching vibration) broad moderate peak near 1580 cm ^-1, 1400 cm ^{- A} broad weak peak in the vicinity of ¹ and a broad medium peak at 1020 cm ⁻¹ were shown. As a result of powder X-ray diffraction measurement, it was assigned to a hexagonal system similar to graphite, and a ₀ = 0.240 nm and c ₀ = 0.740 nm. The specific surface area was 1860 m ² / g, the pore volume was 2.60 cm ³ / g, and the average pore diameter was 1.0 nm. These results indicated that the product was an active BC ₂₀ N material.

"Production Example 12" [Pt-Rh / gamma-alumina] 0.6642g of _{H 2} PtCl ₆ · 6H 2 O for the production of distilled water 20g of catalyst, and was dissolved by adding 0.0153g rhodium chloride. Put this aqueous solution into an evaporating dish, put 5 g of commercially available γ-alumina (manufactured by JGC Chemical Co., Ltd .: specific surface area 250 m ² / g, average pore diameter 6.2 nm), stir uniformly, evaporate to dryness with a steam bath. After solidifying, it was put in a vacuum dryer and vacuum dried at 100 ° C. for 3 hours. This sample was put into a quartz tube and reduced at 500 ° C. for 3 hours in a helium-diluted hydrogen gas (10 v / v%) stream. The supported amounts of platinum and rhodium supported on γ-alumina were 5% by mass and 0.15% by mass, respectively.

"Production Example 13" NOx occlusion reduction type catalyst produced distilled water 20g of _{H 2} PtCl ₆ · 6H 2 O to 0.6642G, and the rhodium chloride 0.0153G, and dissolved by adding 1.762g of barium carbonate. Put this aqueous solution into an evaporating dish, put 5 g of commercially available γ-alumina (manufactured by JGC Chemical Co., Ltd .: specific surface area 250 m ² / g, average pore diameter 6.2 nm), stir uniformly, evaporate to dryness with a steam bath. After solidifying, it was put in a vacuum dryer and vacuum dried at 100 ° C. for 3 hours. This sample was put into a quartz tube and reduced at 500 ° C. for 3 hours in a helium-diluted hydrogen gas (10 v / v%) stream. The supported amounts of platinum, rhodium, and barium supported on γ-alumina were 5 mass%, 0.15 mass%, and 10 mass%, respectively.

Production Example 14 Production of [Pt-Rh / Mesoporous Silica] Catalyst 240 g of ethanol and 30 g of dodecylamine were added to 300 g of distilled water and dissolved. While stirring, 125 g of tetraethoxysilane was added and stirred at room temperature for 22 hours. The product was filtered, washed with water, dried in warm air at 110 ° C. for 5 hours, and then calcined in air at 550 ° C. for 5 hours to decompose and remove the contained dodecylamine to produce mesoporous silica. As a result of small-angle X-ray diffraction measurement of the mesoporous silica, one broad diffraction peak was observed at a 2θ angle of 2.72 degrees (d = 3.25 nm). Further, as a result of observation with a transmission electron microscope, a regular arrangement was not observed in the pore arrangement, and a disordered state was observed. From these results, it was confirmed that the produced mesoporous silica was amorphous with respect to the pore arrangement. As a result of pore distribution and specific surface area measurement, a pore peak was found at a position of about 2.5 nm, the specific surface area was 1123 m ² / g, and the pore volume was 0.89 cm ³ / g.
Then, the _{H 2} PtCl ₆ · 6H 2 O in distilled water 20 g 0.6642G, and rhodium chloride were placed an aqueous solution prepared by dissolving 0.0153g in an evaporating dish, to which the mesoporous silica material 5g addition, a steam bath After evaporating to dryness, it was placed in a vacuum dryer and vacuum dried at 100 ° C. for 3 hours. This sample was put into a quartz tube and reduced at 500 ° C. for 3 hours in a helium-diluted hydrogen gas (10 v / v%) stream. The supported amounts of platinum and rhodium supported on mesoporous silica were 5% by mass and 0.15% by mass, respectively.

"Production Example 15" [Pt-Rh / γ alumina] Catalyst and alkali-activated active BC ₂ N material mixed catalyst 80 mg of Production Example 12 catalyst and 100 mg of Active BC ₂ N material of Production Example 5 were placed in a mortar and homogeneous. A mixture was prepared.
“Production Example 16” [Pt—Rh / Mesoporous Silica] Catalyst and Alkaline-Activated Active BC ₆ N Material Mixed Catalyst Production Example 14 Catalyst 80 mg and Production Example 6 Active BC ₆ N Material 100 mg were uniformly placed in a mortar. A mixture was prepared.
Production Example 17 Production of Mixed Catalyst of [Pt-Rh / Mesoporous Silica] Catalyst and Alkaline-Activated Active BC ₁₂ N Material 80 mg of the catalyst of Production Example 14 and 100 mg of the activated BC ₁₂ N material of Production Example 7 are placed in a mortar and uniform. A mixture was prepared.

“Production Example 18” [Pt—Rh / Mesoporous Silica] Catalyst and Alkaline-Activated Active BC ₂₀ N Material Mixed Catalyst Production 80 mg of the catalyst of Production Example 14 and 100 mg of the active BC ₂₀ N material of Production Example 8 were placed in a mortar uniformly. A mixture was prepared.
Production Example 19 Production of Mixed Catalyst of [Pt-Rh / Mesoporous Silica] Catalyst and Oxo Acid-Activated Active BC ₂₀ N Material 80 mg of the catalyst of Production Example 14 and 100 mg of the active BC ₂₀ N material of Production Example 9 are placed in a mortar. A homogeneously mixed catalyst was produced.
[Production Example 20] [Pt-Rh / mesoporous silica] Production of mixture of catalyst and oxoacid salt activated active BC ₁₆ N material 80 mg of the catalyst of Production Example 14 and 100 mg of the active BC ₁₆ N material of Production Example 10 were placed in a mortar. A homogeneous mixture was produced.
"Production Example 21" [Pt-Rh / Mesoporous Silica] Catalyst and Supercritical Water Activation Activated BC ₂₀ N Material Mixture Production Example 14 Catalyst 80 mg and Production Example 11 Active BC ₂₀ N Material 100 mg in a mortar A homogeneous mixture was produced.

“Production Example 22” [Pt—Rh / mesoporous silica] Production of honeycomb catalyst coated with alkali-activated active BC ₆ N material 12.5 g of powder of active BC ₆ N material of Production Example 6 was added to 100 mL of distilled water. The slurry was prepared by stirring (slurry A). Further, 10 g of the catalyst of Production Example 14 and 1 g of silica sol were added to 100 ml of distilled water and stirred to prepare a slurry (slurry B). A mini-molded body (diameter 38 mm x length 50 mm) cut from a commercially available cordierite monolith molded body (4.5 mil / 400 cells / in ² , diameter 143.8 mm x length 118 mm) is immersed in slurry A, and mini-molded. The body was taken out and air-dried, and then heat-treated in a nitrogen stream at 500 ° C. for 3 hours. Next, after this mini-molded body was immersed in slurry B, the mini-molded body was taken out and air-dried, and then heat-treated in a nitrogen stream at 500 ° C. for 3 hours. The amount of active BC ₆ N material deposited per mini-molded body was 6 g, and the amount of mesoporous silica-supported platinum-rhodium catalyst deposited was 4.6 g.

“Production Example 23” [Pt—Rh / Mesoporous Silica] Catalyst and Untreated BC ₅ N Material Mixed Catalyst Production Example 14 Catalyst 80 mg and Production Example 3 Untreated BC ₅ N Material 100 mg were uniformly placed in a mortar. A mixture was prepared.
"Comparative Example 1" NOx purification performance of [Pt-Rh / γ alumina] catalyst 80 mg of the catalyst of Production Example 12 and 1 ml of sea sand were uniformly mixed, and a continuous flow reaction tube made of quartz (outer diameter 20 mm x inner diameter 16 mm x NOx purification was carried out by circulating a NOx-containing simulated gas whose concentration was adjusted with helium. The component molar concentrations of the simulated gas were 250 ppm nitric oxide, 10% oxygen, and 400 ppm propylene. The flow rate of the simulated gas introduced into the reaction tube was 500 ml per minute. The temperature of the simulated gas at the inlet of the reaction tube was adjusted from 150 ° C to 400 ° C. The NOx concentration contained in the treated gas was measured online to determine the NOx treatment rate. The results are shown in Table 1.

"Comparative Example 2" NOx purification performance of NOx occlusion reduction type catalyst The NOx treatment rate was determined by the same method as Comparative Example 1 using 80 ml of the catalyst of Production Example 13 and 1 ml of powder in which sea sand was uniformly mixed. The results are shown in Table 1.
"Comparative Example 3" NOx purification performance of [Pt-Rh / mesoporous silica] catalyst The NOx treatment rate was determined in the same manner as in Comparative Example 1 using 1 ml of powder in which 80 mg of the catalyst of Production Example 14 and sea sand were uniformly mixed. . The results are shown in Table 1.
"Comparative Example 4" NOx purification performance of a mixture of [Pt-Rh / mesoporous silica] catalyst and untreated BC ₅ N material Comparative Example 1 using 180 mg of the catalyst of Production Example 23 and 1 ml of powder uniformly mixed with sea sand The NOx treatment rate was determined by the same method. The results are shown in Table 1.

"Example 1" [Pt-Rh / γ alumina] catalyst + NOx purification performance of alkali activated BC ₂ N material Same as Comparative Example 1 using 1 ml of powder in which 180 mg of catalyst of Production Example 15 and sea sand were uniformly mixed The NOx treatment rate was determined by the method. The results are shown in Table 1.
"Example 2" [Pt-Rh / mesoporous silica] catalyst + alkali-activated activated BC ₆ N material NOx purification performance The same as in Comparative Example 1 using 180 mg of the catalyst of Production Example 16 and 1 ml of powder in which sea sand was uniformly mixed The NOx treatment rate was determined by the method. The results are shown in Table 1.
"Example 3" [Pt-Rh / mesoporous silica] catalyst + alkali-activated BC ₁₂ N material NOx purification performance The same as Comparative Example 1 using 180 mg of the catalyst of Production Example 17 and 1 ml of powder in which sea sand was uniformly mixed The NOx treatment rate was determined by the method. The results are shown in Table 1.

"Example 4" [Pt-Rh / mesoporous silica] catalyst + alkali-activated BC ₂₀ N material NOx purification performance 80 mg of the catalyst of Production Example 18 and 1 ml of powder obtained by uniformly mixing sea sand were used as in Comparative Example 1. The NOx treatment rate was determined by the method. The results are shown in Table 1.
"Example 5" [Pt-Rh / mesoporous silica] catalyst + oxo acid activation activated BC ₂₀ N material NOx purification performance 80% of the catalyst of Production Example 19 and 1 ml of powder in which sea sand is uniformly mixed, as in Comparative Example 1 The NOx treatment rate was determined by this method. The results are shown in Table 1.
"Example 6" [Pt-Rh / mesoporous silica] catalyst + oxo acid salt activation activated BC ₁₆ N material NOx purification performance 180% of the catalyst of Production Example 20 and 1 ml of powder in which sea sand is uniformly mixed with Comparative Example 1 The NOx treatment rate was determined by the same method. The results are shown in Table 1.

“Example 7” [Pt—Rh / mesoporous silica] catalyst + supercritical water activation activated BC ₂₀ N material NOx purification performance 180% of the catalyst of Production Example 21 and 1 ml of powder in which sea sand is uniformly mixed with Comparative Example 1 The NOx treatment rate was determined by the same method. The results are shown in Table 1.
"EXAMPLE 8" [Pt-Rh / Mesoporous Silica] catalyst + alkali activation activity BC 6 _N material a honeycomb catalyst made of quartz continuous flow reaction tube NOx purification performance Production Example 22 of the coated honeycomb catalyst (outer diameter 46 mm × inner diameter 40 mm × length 500 mm), put in a tubular electric furnace, and circulated a NOx-containing simulated gas whose concentration was adjusted with helium, to perform NOx purification. The component molar concentrations of the simulated gas were 250 ppm nitric oxide, 10% oxygen, and 400 ppm propylene. The flow rate of the simulated gas introduced into the reaction tube was 27.5 liters per minute. The temperature of the simulated gas at the inlet of the reaction tube was adjusted from 160 ° C to 400 ° C. The NOx concentration contained in the treated gas was measured online to determine the NOx treatment rate. The results are shown in Table 2.

表１の結果から、本発明活性Ｂ−Ｃ−Ｎ材料は、低温領域の排ガス浄化に効果があるだけでなく中温領域でも優れた性能を発揮することがわかる。

From the results shown in Table 1, it can be seen that the active B—C—N material of the present invention is not only effective in purifying exhaust gas in a low temperature region, but also exhibits excellent performance in a medium temperature region.

表２の結果から、本発明活性Ｂ−Ｃ−Ｎ材料を塗布した自動車排ガス浄化用ハニカム触媒は、低温から中温領域の全温度領域に渡って優れた浄化性能を示すので、自動車排ガス浄化用に好適であることがわかる。

From the results of Table 2, the honeycomb catalyst for automobile exhaust gas purification coated with the active BCN material of the present invention exhibits excellent purification performance over the entire temperature range from low temperature to medium temperature range. It turns out that it is suitable.

  The active B—C—N material of the present invention can be used for adsorption removal of harmful substances. In particular, it is useful as an adsorption removal material for exhaust gas purification for automobiles.

Claims (6)

An active B—C—N material comprising carbon, nitrogen, and boron, having a specific surface area of 100 to 3000 m ² / g, an average pore diameter of 0.4 to 50 nm, and an oxygen content of the B—C—N material Is an active B—C—N material, characterized in that 1 to 20% by weight. The method for producing an active B—C—N material according to claim 1, wherein a B—C—N material having a specific surface area of 0.1 to 50 m ² / g is activated by an oxidizing agent.   The method for producing an active BCN material according to claim 2, wherein the oxidizing agent is a strongly basic substance.   The method for producing an active B—C—N material according to claim 2, wherein the oxidizing agent is an oxo acid or an oxo acid salt.   The method for producing an active B—C—N material according to claim 2, wherein the oxidizing agent is supercritical water.   An exhaust gas purification method using the activated B—C—N material according to claim 1 for exhaust gas purification.