WO2021059777A1 - Organic matter decomposition catalyst, and organic matter decomposition device - Google Patents

Abstract

This organic matter decomposition catalyst for decomposing organic matter is provided with a carrier and platinum supported on the carrier. The carrier contains, at the surface thereof, an aluminum nitride in which the atomic% ratio N/Al of N and Al is 0.40-0.50.

Description

Organic matter decomposition catalyst and organic matter decomposition equipment

The present invention relates to an organic matter decomposition catalyst used for decomposing an organic substance and an organic matter decomposition apparatus provided with an organic matter decomposition catalyst.

Conventionally, catalysts for decomposing organic substances used for decomposing organic substances are known.

Patent Document 1 describes a catalyst in which a metal catalyst made of a metal or a metal oxide is supported on a carrier made of aluminum nitride. Patent Document 1 describes that this catalyst has high mechanical strength and high thermal conductivity.

The catalyst described in Patent Document 1 is produced by the following method. First, the aluminum nitride powder is calcined at 900 ° C. to 1000 ° C. in the presence of air or oxygen to form an aluminum oxide layer on the surface of the aluminum nitride particles. Subsequently, the aqueous solution containing the copper metal particles is impregnated with the aluminum nitride particles and then dried to obtain a catalyst in which the copper fine particles are supported on the surface of the aluminum nitride. Then, the obtained catalyst is calcined in a temperature range of 350 ° C. to 600 ° C. to obtain catalyst particles.

Japanese Unexamined Patent Publication No. 2003-144933

As described above, in the catalyst described in Patent Document 1, an aluminum oxide layer is formed on the surface of the aluminum nitride particles, but the aluminum oxide layer has a lower thermal conductivity than the aluminum nitride, so that the thermal conductivity of the carrier is low. The rate drops. Therefore, when the catalyst is used in a high temperature environment, heat dissipation does not proceed sufficiently, and sintering of the supported metal fine particles easily proceeds, which may reduce the activity of the catalyst.

The present invention solves the above-mentioned problems, and an organic substance decomposition catalyst capable of suppressing a decrease in catalytic activity when used in a high temperature environment, and an organic substance provided with such an organic substance decomposition catalyst. It is an object of the present invention to provide a disassembling device.

The catalyst for decomposing an organic substance of the present invention is a catalyst for decomposing an organic substance used for decomposing an organic substance, and comprises a carrier and platinum supported on the carrier, and the carrier is present on the surface of N. It is characterized by containing aluminum nitride having an atomic% ratio N / Al of 0.40 or more and 0.50 or less.

According to the catalyst for decomposing organic substances of the present invention, it is possible to suppress a decrease in catalytic activity when used in a high temperature environment.

It is a figure which shows the photograph when the surface of the catalyst for organic matter decomposition of Example 1 was observed. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Example 2. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Example 3. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Example 4. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Example 6. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Comparative Example 1. It is a figure which shows the photograph when the surface of the catalyst for organic matter decomposition of the comparative example 2 was observed, (a) is the photograph when the observation magnification is 100,000 times, (b) is the observation magnification. The photograph when it is multiplied by 600,000 is shown. It is a figure which shows the photograph when the surface of the catalyst for organic matter decomposition of the comparative example 3 was observed, (a) is the photograph when the observation magnification is 150,000 times, (b) is the observation magnification. The photograph when it is multiplied by 600,000 is shown. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Comparative Example 4. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Comparative Example 5. It is a figure which shows the photograph at the time of observing the surface of the catalyst for organic matter decomposition of Comparative Example 7. It is a figure which shows the relationship between the average particle diameter of platinum particles of the catalyst for organic matter decomposition of Examples 1 to 4 and Comparative Examples 1 to 5, _{and the amount of H 2 gas adsorbed per platinum mass after heat treatment at 800 degreeC.} Regarding the organic matter decomposition catalysts of Examples 1 to 8 and Comparative Examples 6 to 9, the organic matter decomposition catalysts of _{Comparative Examples having the same amount of H 2} gas adsorbed per platinum mass and the same amount of platinum supported after heat treatment at 800 ° C. It is a figure which shows the relationship with the ratio _{of the H 2} gas unit adsorption amount after the heat treatment at 800 degreeC when compared. Regarding the organic matter decomposition catalysts of Examples 1 to 8 and Comparative Examples 11 to 14, the organic matter decomposition catalysts of _{Comparative Examples having the same amount of H 2} gas adsorbed per platinum mass and the same amount of platinum supported after heat treatment at 800 ° C. It is a figure which shows the relationship with the ratio _{of the H 2} gas unit adsorption amount after the heat treatment at 800 degreeC when compared.

Hereinafter, embodiments of the present invention will be shown, and the features of the present invention will be specifically described.

The catalyst for decomposing an organic substance according to the present invention is a catalyst for decomposing an organic substance used for decomposing an organic substance, and comprises a carrier and platinum supported on the carrier, and the carrier is composed of N and Al existing on the surface thereof. It satisfies the requirement of containing aluminum nitride having an atomic% ratio N / Al of 0.40 or more and 0.50 or less (hereinafter, referred to as the requirement of the present invention).

As will be described later, the catalyst for decomposing organic substances that satisfies the requirements of the present invention can suppress a decrease in activity when used in a high temperature environment such as 800 ° C. This catalyst for decomposing organic substances can be used for various purposes for decomposing organic substances, such as purification of exhaust gas from factories and automobiles. In that case, it can be configured as an organic matter decomposition apparatus provided with a catalyst for organic matter decomposition that satisfies the requirements of the present invention.

The organic substance to be decomposed is, for example, toluene. When toluene is steam reformed using the organic matter decomposition catalyst according to the present invention, H ₂ is adsorbed on the organic matter decomposition catalyst. Therefore, _{by confirming the amount of H 2} adsorbed during the decomposition of toluene, the amount of decomposition and the decomposition rate of toluene, which is an organic substance, can be confirmed.

However, the organic matter to be decomposed is not limited to toluene. Further, the method of decomposing organic substances is not limited to steam reforming, and carbon dioxide may be used, for example.

The catalysts for decomposing organic substances of Examples 1 to 8 described below are catalysts that satisfy the above-mentioned requirements of the present invention. In the catalysts for organic matter decomposition of Examples 1 to 8, the carrier is made of aluminum nitride having an atomic% ratio N / Al of N and Al existing on the surface of 0.40 or more and 0.50 or less. Further, the catalysts for organic matter decomposition of Examples 1 to 8 do not contain chlorine.

(Example 1)
The catalyst for organic matter decomposition of Example 1 was prepared by the following procedures 1 to 3.

<Operation 1>
Bisacetylacetonate platinum (II) was dissolved in toluene by ultrasonic irradiation to prepare a solution having a platinum content of 1% by mass. Bisacetylacetonate platinum (II) is a platinum salt whose chemical structure does not contain chlorine.

<Operation 2>
An aluminum nitride dispersion having a mass of 0.5 g and an average particle size of D50 of 1.2 μm was added to the above-mentioned solution in which bisacetylacetonate platinum (II) was dissolved to prepare an aluminum nitride dispersion. The amount of the solution was adjusted so that the target loading amount of platinum was 1% by mass. Then, a beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride dispersion was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3>
After evaporation to dryness, the dried product remaining in the beaker was added to the crucible, and the crucible was placed in a heat treatment furnace and heat-treated at 500 ° C. for 1 hour under atmospheric conditions. After that, the crucible was taken out from the heat treatment furnace whose temperature was lowered to 100 ° C. or lower, and again under mixed gas flow in which the ratio of _{H 2} to N _{2 (H 2} / N _{2) was 3% at 400 ° C. for 1 hour.} The catalyst for organic matter decomposition of Example 1 was prepared by performing the heat treatment in.

<Operation 4>
The prepared catalyst for decomposition of organic matter was heat-treated at 800 ° C. for 2 hours under atmospheric conditions.

<Operation 5>
By wide scan spectrum measurement by X-ray photoelectron spectroscopy (XPS), qualitative and semi-quantitative analysis of the surface of the catalyst for organic matter decomposition after heat treatment by the above operation 4 was performed. The measurement area was φ100 mm, and the analysis depth was several nm. Table 1 shows the results of qualitative and semi-quantitative analysis of the elements.

<Operation 6>
The catalyst for decomposition of organic matter was recovered from the crucible, and 0.02 g was added to the sample tube. Then, the catalyst for decomposition of organic substances is desorbed from adsorbents such as water at 400 ° C. using a catalyst analyzer "BELCAT" manufactured by Microtrac Bell, cooled to 50 ° C., and then subjected to a pulse chemisorption method. , The _{amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined. In the pulse chemisorption method, Ar was used as the carrier gas, and H ₂ gas having a concentration of 5% by volume was repeatedly introduced in a pulse shape. The flow rate of the introduced gas is 30 cm ³ / min, and the measurement temperature stabilization time is 15 minutes.

The H ₂ gas was flowed into the measuring tube for 120 seconds and injected into the sample tube 10 seconds later. The judgment value of pulse detection was 0.001 mV / sec, and it was judged that the adsorption equilibrium was reached within 1.2% of the difference between the detectors of the final 3 pulses. As a result, the _{amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined. _{Here, "of H 2} gas _{" obtained by dividing the adsorption amount of H 2} gas by the mass of the catalyst for decomposition of organic substances both before and after the heat treatment at 800 ° C. according to operation 4. a unit adsorption amount ", the amount of adsorption of H ₂ gas were determined and obtained by dividing the mass of the platinum" H ₂ gas adsorption amount per platinum mass ".

<Operation 7>
Using the field emission transmission electron microscope "JEM-2200FS" manufactured by JEOL Ltd. and the energy dispersive X-ray analyzer "NORAN System seven" manufactured by Hitachi, the surface of the catalyst for organic matter decomposition after the heat treatment by the above operation 4 is used. Observed. FIG. 1 shows a photograph when the surface of the catalyst for organic matter decomposition of Example 1 was observed at an observation magnification of 150,000 times. As shown in FIG. 1, platinum (platinum nanoparticles) 2 is supported on the carrier 1 of the organic matter decomposition catalyst 10. Further, as shown in FIG. 1, even after the heat treatment at a high temperature such as 800 ° C., the supported platinum nanoparticles are not coarsened due to excessive sintering and aggregation.

In addition, in order to obtain the average particle size of the supported platinum nanoparticles, the observation magnification was set to 500,000 times, and 40 platinum nanoparticles from a plurality of fields of view were binarized using image analysis software. Was performed, and the equivalent circle diameter was measured. The average value of the measured 40 circle-equivalent diameters was calculated and used as the average particle size of the platinum nanoparticles.

(Example 2)
The organic matter decomposition catalyst of Example 2 was prepared by the same operations as in Operations 1 to 3 of Example 1 except that the target loading amount of platinum was adjusted to be 2% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 4 of Example 1.

_{In addition, the amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined by the same method as described in step 6 of Example 1. From the adsorption amount of H ₂ gas was determined and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

Further, the surface of the catalyst for organic matter decomposition of Example 2 was observed by the same method as that described in Operation 7 of Example 1. A photograph of the surface of the catalyst for decomposing organic matter of Example 2 is shown in FIG.

Further, the average particle size of the supported platinum nanoparticles was determined by the same method as that described in operation 7 of Example 1.

(Example 3)
The organic matter decomposition catalyst of Example 3 was prepared by the same operations as in Operations 1 to 3 of Example 1 except that the target loading amount of platinum was adjusted to 3% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 4 of Example 1.

_{In addition, the amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined by the same method as described in step 6 of Example 1. From the adsorption amount of H ₂ gas was determined and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

Further, the surface of the catalyst for organic matter decomposition of Example 3 was observed by the same method as that described in Operation 7 of Example 1. A photograph of the surface of the catalyst for decomposing organic matter of Example 3 is shown in FIG.

Further, the average particle size of the supported platinum nanoparticles was determined by the same method as that described in operation 7 of Example 1.

(Example 4)
The organic matter decomposition catalyst of Example 4 was prepared by the same operations as in Operations 1 to 3 of Example 1 except that the target loading amount of platinum was adjusted to 5% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 4 of Example 1.

The surface of the catalyst for organic matter decomposition of Example 4 was qualitatively and semi-quantitatively analyzed by the same method as that described in Operation 5 of Example 1. Table 2 shows the results of qualitative and semi-quantitative analysis of the elements.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined by the same method as described in step 6 of Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

Further, the surface of the catalyst for organic matter decomposition of Example 4 was observed by the same method as that described in Operation 7 of Example 1. A photograph of the surface of the catalyst for decomposing organic matter of Example 4 is shown in FIG.

Further, the average particle size of the supported platinum nanoparticles was determined by the same method as that described in the above operation 7.

After dissolving each of the above-mentioned catalysts for decomposition of organic substances in Examples 1 to 4 by acid treatment, the insoluble matter was filtered, and the mass% of platinum in the filtrate was measured. The mass% of this platinum means the actual amount of platinum supported. The mass% of platinum was measured twice using an ICP emission spectrometer "iCAP6300" manufactured by Thermo Fisher Scientific Co., Ltd., and the average value was obtained. For Examples 1 to 4, the target carrier amount of platinum and the actual carrier amount of platinum are shown in Table 3.

As shown in Table 3, it was found that the actual supported amount of platinum did not deviate significantly from the target supported amount.

(Example 5)
The catalyst for organic matter decomposition of Example 5 was prepared by the following procedures from Operation 1A to Operation 3A.

<Operation 1A>
Hexachloroplatinic acid (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 1% by mass. Hexachloroplatin (IV) acid / hexahydrate is a platinum salt whose chemical structure does not contain chlorine.

<Operation 2A>
An aluminum nitride dispersion having a mass of 0.5 g and an average particle size of D50 of 1.2 μm was added to the above-mentioned solution in which hexachloride platinum (IV) acid / hexahydrate was dissolved to prepare an aluminum nitride dispersion. The amount of the solution was adjusted so that the target loading amount of platinum was 1% by mass. A beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride solution was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3A>
After evaporating to dryness, the catalyst for organic matter decomposition of Example 5 was prepared by performing heat treatment under the same conditions and the same method as the heat treatment conditions of Operation 3 of Example 1.

<Operation 4A>
The produced catalyst for decomposition of organic matter was heat-treated under the same conditions as the heat treatment conditions of operation 4 of Example 1.

<Operation 5A>
A qualitative and semi-quantitative analysis of the surface of the catalyst for organic matter decomposition of Example 5 was performed by the same method as that described in Operation 5 of Example 1. Table 4 shows the results of qualitative and semi-quantitative analysis of the elements.

<Operation 6A>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in step 6 of Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Example 6)
The organic matter decomposition catalyst of Example 6 was prepared by the same method as the organic matter decomposition catalyst of Example 5 except that the target carrying amount of platinum was adjusted to be 2% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 4 of Example 1.

_{In addition, the amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined by the same method as described in step 6 of Example 1. From the adsorption amount of H ₂ gas was determined and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

Further, the surface of the catalyst for organic matter decomposition of Example 6 was observed by the same method as that described in Operation 7 of Example 1. A photograph of the surface of the catalyst for decomposing organic matter of Example 6 is shown in FIG.

Further, the average particle size of the supported platinum nanoparticles was determined by the same method as that described in operation 7 of Example 1.

(Example 7)
The organic matter decomposition catalyst of Example 7 was prepared by the same method as the organic matter decomposition catalyst of Example 5 except that the target carrying amount of platinum was adjusted to 3% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 4 of Example 1.

_{In addition, the amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined by the same method as described in step 6 of Example 1. From the adsorption amount of H ₂ gas was determined and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Example 8)
The organic matter decomposition catalyst of Example 8 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Example 5 except that the target carrying amount of platinum was adjusted to 5% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 4 of Example 1.

Further, qualitative and semi-quantitative analysis of the surface of the catalyst for organic matter decomposition of Example 8 was performed by the same method as that described in Operation 5 of Example 1. Table 5 shows the results of qualitative and semi-quantitative analysis of the elements.

_{In addition, the amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined by the same method as described in step 6 of Example 1. From the adsorption amount of H ₂ gas was determined and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

The catalysts for decomposition of organic substances of Comparative Examples 1 to 14 described below are catalysts that do not satisfy the above-mentioned requirements of the present invention.

(Comparative Example 1)
The catalyst for decomposition of organic matter of Comparative Example 1 was prepared by the following procedures 1B to 5B.

<Operation 1B>
Hexachloroplatin (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 5% by mass.

<Operation 2B>
An aluminum nitride dispersion having a mass of 0.5 g and an average particle size of D50 of 1.2 μm was added to the above-mentioned solution in which hexachloride platinum (IV) acid / hexahydrate was dissolved to prepare an aluminum nitride dispersion. Then, the produced aluminum nitride dispersion was stirred with a stirrer at 300 rpm.

Then, 50 mL of 0.1 M sodium hydroxide prepared by dissolving in pure water was added to the above-mentioned aluminum nitride dispersion, and 10 mL of a 1 M sodium hydroxide aqueous solution was additionally added. After 30 minutes were required for pH adjustment, the pH of the aluminum nitride dispersion was examined using a Lithomas test paper and found to be 12. After that, the aluminum nitride dispersion was stirred at 70 ° C. after the pH reached 12. Since the pH was 11 after 45 minutes of stirring, 5 mL of 1 M aqueous sodium hydroxide solution was added to maintain the pH at 12. After that, the pH of the aluminum nitride dispersion did not change in 15 minutes.

<Operation 3B>
The aluminum nitride dispersion was solid-liquid separated using a membrane filter having a pore size of 1 μm. The surface of the powder existing on the surface of the membrane filter was washed by performing suction filtration three times with 20 mL of pure water.

<Operation 4B>
The powder recovered from the membrane filter using a spatula was placed in an aluminum petri dish and dried overnight at room temperature using a vacuum low temperature dryer.

<Operation 5B>
The dried product obtained by the above operation 4B was transferred from an aluminum petri dish to a crucible and heat-treated in the atmosphere at 500 ° C. for 1 hour. Then, after taking out the crucible from the heat treatment furnace whose temperature was lowered to 100 ° C. or lower, the mixed gas flow in which the ratio of _{H 2} to N _{2 (H 2} / N _{2) was 3% again at 400 ° C. for 1 hour.} By heat-treating underneath, a catalyst for decomposition of organic matter of Comparative Example 1 was prepared.

<Operation 6B>
The surface of the produced catalyst for decomposition of organic matter was observed using a scanning electron microscope "HD-2300A" manufactured by Hitachi and an energy dispersive X-ray analyzer "Genesis XM4" manufactured by EDAX. The observation photograph is shown in FIG. By observing the surface of the catalyst for decomposition of organic matter, it was confirmed that platinum nanoparticles having a size of about 5 nm were uniformly supported on the surface of aluminum nitride.

<Operation 7B>
The prepared catalyst for decomposition of organic matter was added to the crucible, and the mixture was further heat-treated at 800 ° C. for 2 hours in the atmosphere.

<Operation 8B>
The catalyst for decomposition of organic matter was recovered from the crucible, and 0.1 g was added to the sample tube. Then, the catalyst for decomposition of organic substances is desorbed from adsorbents such as water at 400 ° C. using a catalyst analyzer "BELCAT" manufactured by Microtrac Bell, cooled to 50 ° C., and then subjected to a pulse chemisorption method. , The _{amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined. In the pulse chemisorption method, Ar was used as the carrier gas, and H ₂ gas having a concentration of 5% by volume was repeatedly introduced in a pulse shape. The flow rate of the introduced gas is 30 cm ³ / min, and the measurement temperature stabilization time is 15 minutes.

The H ₂ gas was flowed into the measuring tube for 120 seconds and injected into the sample tube 10 seconds later. The judgment value of pulse detection was 0.001 mV / sec, and it was judged that the adsorption equilibrium was reached within 1.2% of the difference between the detectors of the final 3 pulses. As a result, the _{amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles were determined. Again, before performing the heat treatment at 800 ° C. due to the operation 7C, both after the heat treatment, the adsorption amount of H ₂ gas, obtained by dividing by the mass of organic decomposition catalyst "of the H ₂ gas a unit adsorption amount ", the amount of adsorption of H ₂ gas were determined and obtained by dividing the mass of the platinum" H ₂ gas adsorption amount per platinum mass ".

(Comparative Example 2)
The catalyst for decomposition of organic matter of Comparative Example 2 was prepared by the following procedures 1C to 5C.

<Operation 1C>
Hexachloroplatinic acid (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 0.58% by mass and 30 mM.

<Operation 2C>
After ultrasonically dispersing aluminum nitride powder having a mass of 0.5 g and an average particle size D50 of 1.2 μm in 2 mL of pure water with an ultrasonic cleaner, the above-mentioned hexachloride platinum (IV) acid / hexahydrate was obtained. An aluminum nitride dispersion was prepared by adding 4 mL of a solution dissolved in pure water. The amount of the solution added was adjusted so that the target loading amount of platinum was 5% by mass. Then, a beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride dispersion was stirred at room temperature and 500 rpm for 1 hour.

<Operation 3C>
0.85 g of sodium borohydride was weighed and dissolved in 9.15 mL of pure water subjected to _{N 2 bubbling overnight to prepare a reducing agent.} The concentration of the reducing agent is 85 g / L. The prepared reducing agent was slowly added dropwise to the aluminum nitride dispersion using a micropipette. The dropping of the reducing agent caused vigorous foaming, and the yellowish aluminum nitride dispersion instantly turned gray. After defoaming, the aluminum nitride dispersion was stirred for 2 hours.

<Operation 4C>
The aluminum nitride dispersion was solid-liquid separated using a membrane filter having a pore size of 1 μm. The surface of the powder existing on the surface of the membrane filter was washed by performing suction filtration three times with 20 mL of ethanol.

<Operation 5C>
The powder recovered from the membrane filter using a spatula is placed in an aluminum petri dish and dried at 60 ° C. for 30 minutes under atmospheric conditions using a constant temperature dryer to obtain the catalyst for organic matter decomposition of Comparative Example 2. Made.

<Operation 6C>
The surface of the produced catalyst for decomposition of organic matter was observed by the same method as that described in Operation 6B of Comparative Example 1. The observation photograph is shown in FIG. FIG. 7A is a photograph when the observation magnification is 100,000 times, and FIG. 7B is a photograph when the observation magnification is 600,000 times. By observing the surface of the catalyst for decomposition of organic matter, it was confirmed that platinum nanoparticles having a size of about 15 nm were uniformly supported on the surface of aluminum nitride.

<Operation 7C>
The prepared catalyst for decomposition of organic matter was added to the crucible, and the mixture was further heat-treated at 800 ° C. for 2 hours in the atmosphere.

<Operation 8C>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 3)
The catalyst for organic matter decomposition of Comparative Example 3 was produced by the following procedures from Operation 1D to Operation 5D.

<Operation 1D>
In the same manner as in Operation 1B of Comparative Example 1, hexachloride platinum (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 5% by mass.

<Operation 2D>
1.3 mL of 1 M aqueous sodium hydroxide solution was added to the solution in which hexachloride platinum (IV) acid / hexahydrate was dissolved. The pH of this solution was measured using a pH meter manufactured by HORIBA, Ltd. and found to be 12.43.

Subsequently, an aluminum nitride dispersion having a mass of 1 g and an average particle size of D50 of 1.2 μm was added to the above-mentioned pH-adjusted solution to prepare an aluminum nitride dispersion. Then, a beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride dispersion was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3D>
The aluminum nitride dispersion was solid-liquid separated by the same cleaning method as that described in Operation 3B of Comparative Example 1, and then the powder surface existing on the membrane filter surface was cleaned.

<Operation 4D>
The powder was dried by the same method as the drying method described in Operation 4B of Comparative Example 1.

<Operation 5D>
The organic matter decomposition catalyst of Comparative Example 3 was prepared by heat-treating the dried product by the same method as the heat treatment method described in Operation 5B of Comparative Example 1.

<Operation 6D>
The surface of the produced catalyst for decomposition of organic matter was observed by the same method as that described in Operation 6B of Comparative Example 1. The observation photograph is shown in FIG. FIG. 8A is a photograph when the observation magnification is 150,000 times, and FIG. 8B is a photograph when the observation magnification is 600,000 times. By observing the surface of the catalyst for decomposition of organic matter, it was confirmed that platinum nanoparticles having a size of about 25 nm were uniformly supported on the surface of aluminum nitride.

<Operation 7D>
The organic matter decomposition catalyst was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

<Operation 8D>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 4)
The catalyst for decomposition of organic matter of Comparative Example 4 was prepared by the following procedures from Operation 1E to Operation 5E.

<Operation 1E>
In the same manner as in Operation 1B of Comparative Example 1, hexachloride platinum (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 5% by mass.

<Operation 2E>
1.23 mL of 1 M aqueous sodium hydroxide solution was added to the solution in which hexachloride platinum (IV) acid / hexahydrate was dissolved. The pH of this solution was measured using a pH meter manufactured by HORIBA, Ltd. and found to be 7.09.

Subsequently, an aluminum nitride dispersion having a mass of 1 g and an average particle size of D50 of 1.2 μm was added to the above-mentioned pH-adjusted solution to prepare an aluminum nitride dispersion. Then, a beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride dispersion was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3E>
The aluminum nitride dispersion was solid-liquid separated by the same cleaning method as that described in Operation 3B of Comparative Example 1, and then the powder surface existing on the membrane filter surface was cleaned.

<Operation 4E>
The powder recovered from the membrane filter using a spatula was placed in an aluminum petri dish and dried at 110 ° C. for 3 hours under atmospheric conditions using a constant temperature dryer.

<Operation 5E>
The organic matter decomposition catalyst of Comparative Example 4 was prepared by heat-treating the dried product by the same method as the heat treatment method described in Operation 5B of Comparative Example 1.

<Operation 6E>
The surface of the produced catalyst for decomposition of organic matter was observed by the same method as that described in Operation 6B of Comparative Example 1. The observation photograph is shown in FIG. By observing the surface of the catalyst for decomposition of organic matter, it was confirmed that platinum nanoparticles having a size of about 50 nm were uniformly supported on the surface of aluminum nitride.

<Operation 7E>
The organic matter decomposition catalyst was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

<Operation 8E>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 5)
The catalyst for organic matter decomposition of Comparative Example 5 was produced by the following procedures from Operation 1F to Operation 5F.

<Operation 1F>
In the same manner as in Operation 1B of Comparative Example 1, hexachloride platinum (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 5% by mass.

<Operation 2F>
1.30 mL of a 1 M aqueous sodium hydroxide solution was added to a solution in which hexachloride platinum (IV) acid / hexahydrate was dissolved. The pH of this solution was measured using a pH meter manufactured by HORIBA, Ltd. and found to be 12.43.

Subsequently, an aluminum nitride dispersion having a mass of 1 g and an average particle size of D50 of 1.2 μm was added to the above-mentioned pH-adjusted solution to prepare an aluminum nitride dispersion. Then, a beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride dispersion was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3F>
The aluminum nitride dispersion was solid-liquid separated by the same cleaning method as that described in Operation 3B of Comparative Example 1, and then the powder surface existing on the membrane filter surface was cleaned.

<Operation 4F>
The powder was dried by the same method as the drying method described in Operation 4B of Comparative Example 1.

<Operation 5F>
The organic matter decomposition catalyst of Comparative Example 5 was prepared by heat-treating the dried product by the same method as the heat treatment method described in Operation 5B of Comparative Example 1.

<Operation 6F>
The surface of the produced catalyst for decomposition of organic matter was observed by the same method as that described in Operation 6B of Comparative Example 1. The observation photograph is shown in FIG. By observing the surface of the catalyst for decomposition of organic matter, it was confirmed that platinum nanoparticles having a size of about 60 nm were uniformly supported on the surface of aluminum nitride.

<Operation 7F>
The organic matter decomposition catalyst was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

<Operation 8F>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 6)
The catalyst for organic matter decomposition of Comparative Example 6 was produced by the following procedures from Operation 1G to Operation 3G.

<Operation 1G>
Hexachloroplatinic acid (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 1% by mass.

<Operation 2G>
An α-alumina dispersion was prepared by adding 0.5 g of α-alumina powder having a particle size of about 2 to 3 μm to the solution in which the above-mentioned hexachloride platinum (IV) acid / hexahydrate was dissolved. The amount of the solution was adjusted so that the target loading amount of platinum was 1% by mass. Then, a beaker containing the α-alumina dispersion was placed on a hot stirrer, and the α-alumina dispersion was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3G>
After evaporating to dryness, the catalyst for organic matter decomposition of Comparative Example 6 was produced by performing heat treatment in the same manner as the heat treatment method described in Operation 5B of Comparative Example 1.

<Operation 4G>
The produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

<Operation 5G>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 7)
The organic matter decomposition catalyst of Comparative Example 7 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 6 except that the target carrying amount of platinum was adjusted to be 2% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

The surface of the catalyst for organic matter decomposition of Comparative Example 7 was observed by the same method as that described in Operation 7 of Example 1. FIG. 11 shows a photograph of Comparative Example 7 when the surface of the catalyst for decomposition of organic matter was observed.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

Further, the average particle size of the supported platinum nanoparticles was determined by the same method as that described in operation 7 of Example 1.

(Comparative Example 8)
The organic matter decomposition catalyst of Comparative Example 8 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 6 except that the target carrying amount of platinum was adjusted to 3% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 9)
The organic matter decomposition catalyst of Comparative Example 9 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 6 except that the target carrying amount of platinum was adjusted to 5% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 10)
The catalyst for organic matter decomposition of Comparative Example 10 was prepared by the following procedures from Operation 1H to Operation 3H. The catalyst for decomposition of organic matter in Comparative Example 10 corresponds to the catalyst of Example 19 described in JP-A-2003-144933.

<Operation 1H>
Hexachloroplatinic acid (IV) acid / hexahydrate was dissolved in pure water by ultrasonic irradiation to prepare a solution having a platinum content of 0.58% by mass and 30 mM.

<Operation 2H>
Aluminum nitride powder having an average particle size D50 of 1.2 μm was heat-treated at 1000 ° C. for 2 hours under atmospheric conditions. 0.5 g of the heat-treated aluminum nitride powder was added to the above-mentioned solution in which the hexachloride platinum (IV) acid / hexahydrate was dissolved to prepare an aluminum nitride dispersion. The amount of the solution was adjusted so that the target loading amount of platinum was 0.5% by mass. A beaker containing the aluminum nitride dispersion was placed on a hot stirrer, and the aluminum nitride dispersion was dried while stirring with a stirring rod at a set temperature of 100 ° C.

<Operation 3H>
After evaporating to dryness, a catalyst for decomposition of organic substances of Comparative Example 10 was prepared by performing a heat treatment in the same manner as the heat treatment method described in Operation 5B of Comparative Example 1.

<Operation 4H>
A qualitative and semi-quantitative analysis of the surface of the catalyst for organic matter decomposition of Comparative Example 10 was performed by the same method as that described in Operation 5 of Example 1. Table 6 shows the results of qualitative and semi-quantitative analysis of the elements.

<Operation 5H>
The heat treatment was performed by the same method as the heat treatment method described in the operation 7B of Comparative Example 1.

<Operation 6H>
_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 11)
The organic matter decomposition catalyst of Comparative Example 11 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 10 except that the target carrying amount of platinum was adjusted to 1% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 12)
The organic matter decomposition catalyst of Comparative Example 12 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 10 except that the target carrying amount of platinum was adjusted to be 2% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 13)
The organic matter decomposition catalyst of Comparative Example 13 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 10 except that the target carrying amount of platinum was adjusted to be 3% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

(Comparative Example 14)
The organic matter decomposition catalyst of Comparative Example 14 was prepared by the same method as the method for producing the organic matter decomposition catalyst of Comparative Example 10 except that the target carrying amount of platinum was adjusted to 5% by mass. Further, the produced catalyst for decomposition of organic matter was heat-treated by the same method as the heat treatment method described in operation 7B of Comparative Example 1. The catalyst for decomposition of organic matter of Comparative Example 14 corresponds to the catalyst of Example 20 described in JP-A-2003-144933.

The surface of the catalyst for organic matter decomposition of Comparative Example 14 was qualitatively and semi-quantitatively analyzed by the same method as that described in Operation 5 of Example 1. Table 7 shows the results of qualitative and semi-quantitative analysis of the elements.

_{The amount of H 2} gas adsorbed and the degree of dispersion of platinum nanoparticles supported on the carrier were determined by the same method as described in Operation 8B of Comparative Example 1. Further, it determined from the adsorption amount of H ₂ gas, and the unit amount of adsorption of H ₂ gas before and after the heat treatment is performed at 800 ° C., and H ₂ gas adsorption amount per platinum mass.

Here, the qualitative / semi-quantitative analysis results of the surfaces of the catalysts for organic matter decomposition of Examples 1, 4, 5 and 8 and Comparative Examples 10 and 14 and the atomic% ratio N / Al of N and Al existing on the surface are shown. Shown in 8.

As shown in Table 8, the atomic% ratio N / Al of N and Al present on the surface of the carrier of the catalyst for organic matter decomposition of Examples 1, 4, 5, and 8 is 0.40 or more and 0.50 or less. .. Although not shown in Table 8, the atomic% ratio N / Al of N and Al present on the surface of the carrier of the catalyst for organic matter decomposition of Examples 2, 3, 6 and 7 is 0.40 or more and 0.50. It was also confirmed that it was as follows. Further, not only the organic matter decomposition catalysts of Comparative Examples 10 and 14 but also the atomic% ratio N / Al of N and Al present on the surface of the carrier of the organic matter decomposition catalysts of Comparative Examples 1 to 9 and 11 to 13 was 0. It was also confirmed that it was out of the range of 40 or more and 0.50 or less.

Regarding the catalysts for organic substance decomposition of Examples 1 to 8 and Comparative Examples 1 to 14 described above, the target loading amount of platinum, the _{adsorption amount of H 2} gas unit after heat treatment at 800 ° C., the adsorption amount of H ₂ gas per platinum mass, and the heat treatment. H ₂ gas adsorption amount per H ₂ gas unit adsorption amount and the platinum mass before, and show a reduction rate of the H ₂ gas adsorption amount per platinum mass by annealing 800 ° C. Table 9. _{The reduction rate R of the H 2} gas adsorption amount per platinum mass due to the heat treatment is as follows, assuming that the H _{2 gas adsorption amount per platinum mass before the heat treatment is Q1 and the H 2} gas adsorption amount per platinum mass after the heat treatment is Q2. It is represented by the formula (1).
R = (Q1-Q2) / Q1 × 100 (1)

As shown in Table 9, the catalysts for organic matter decomposition of Comparative Examples 1 to 14 which do not satisfy the requirements of the present invention have _{a reduction rate of H 2} gas adsorption amount per platinum mass of 94% or more before and after the heat treatment at 800 ° C. I grew up. On the other hand, in the catalysts for organic matter decomposition of Examples 1 to 8 satisfying the requirements of the present invention, _{the reduction rate of the amount of H 2} gas adsorbed per platinum mass before and after the heat treatment at 800 ° C. is 61% or more and 94% or less. It was. That is, the catalysts for decomposing organic substances of Examples 1 to 8 satisfying the requirements of the present invention suppress the decrease in the amount of _{H 2 gas adsorbed when used in a high temperature environment such as 800 ° C., and decrease the catalytic activity.} Can be suppressed.

Further, as shown in Table 9, Example 1 organic decomposition catalyst of 1-8, 800 H ₂ gas adsorption amount per platinum mass in after heat treatment at ℃ is 0.46 cm ³ / g or more 1.61cm ³ / It is less than or equal to g.

Further, for the catalysts for organic matter decomposition of Examples 1 to 8 and Comparative Examples 1 to 14 described above, the target carrying amount of platinum, the dispersity of platinum after the heat treatment at 800 ° C., and the dispersity of platinum before the heat treatment are shown. Shown in 10.

Table 11 shows the target loading amount of platinum and the average particle size of platinum particles for the catalysts for organic matter decomposition in Examples 1 to 4, 6 and Comparative Examples 1 to 5, 7. For the catalysts for organic matter decomposition of Examples 1 to 4, 6 and Comparative Example 7, the standard deviation, the minimum value, and the maximum value of the particle size of the platinum particles are also shown.

As shown in Table 11, the average particle size of the platinum particles of the catalysts for organic matter decomposition in Examples 1 to 4 and 6 is 28 nm or more and 41 nm or less. It has also been confirmed that the average particle size of the platinum particles of the catalysts for decomposition of organic substances in Examples 5, 7 and 8 is 28 nm or more and 41 nm or less.

FIG. 12 is a diagram showing the relationship between the average particle size of platinum particles of the catalysts for organic matter decomposition of Examples 1 to 4 and Comparative Examples 1 to 5 _{and the amount of H 2 gas adsorbed per platinum mass after heat treatment at 800 ° C.} Is. As shown in FIG. 12, the organic matter decomposition catalysts of Examples 1 to 4 satisfying the requirements of the present invention have a temperature of 800 ° C. as compared with the organic matter decomposition catalysts of Comparative Examples 1 to 5 which do not satisfy the requirements of the present invention. It can be seen that the amount _{of H 2} gas adsorbed per platinum mass after the heat treatment is large.

FIG. 13 shows the organic substances of Comparative Examples having the same amount of platinum supported as the amount _{of H 2} gas adsorbed per platinum mass after heat treatment at 800 ° C. for the catalysts for decomposition of organic substances of Examples 1 to 8 and Comparative Examples 6 to 9. when compared to cracking catalyst is a diagram showing the relationship between the ratio P1 of the H ₂ gas unit amount of adsorption after heat treatment of 800 ° C.. The ratio P1 of the H ₂ gas unit adsorption amount, the H ₂ gas unit amount of adsorption after heat treatment 800 ° C. of the catalyst for decomposing organic substances of Examples 1 ~ 8 K1, the amount of platinum supported equivalent to their organic decomposition catalyst It is represented by K1 / K2 when the amount _{of H 2} gas unit adsorbed after the heat treatment of the organic substance decomposition catalyst of Comparative Example (any of Comparative Examples 6 to 9) at 800 ° C. is K2. The ratio P1 of the _{H 2} gas unit adsorption amount for the organic matter decomposition catalysts of Comparative Examples 6 to 9 is 1.

FIG. 14 shows the organic substances of Comparative Examples of Examples 1 to 8 and Comparative Examples 11 to 14 _{having the same amount of H 2} gas adsorbed per platinum mass after heat treatment at 800 ° C. and the same amount of platinum supported. It is a figure which shows the relationship with the ratio P2 _{of the H 2} gas unit adsorption amount after the heat treatment at 800 degreeC when compared with the decomposition catalyst. The H ₂ gas unit adsorption ratio P2 is H ₂ gas unit amount of adsorption after heat treatment 800 ° C. of the catalyst for decomposing organic substances of Examples 1 ~ 8 K1, the amount of platinum supported equivalent to their organic decomposition catalyst It is represented by K1 / K3 when the amount _{of H 2} gas unit adsorbed after the heat treatment of the organic substance decomposition catalyst of Comparative Example (any of Comparative Examples 11 to 14) at 800 ° C. is K3. The ratio P2 of the _{H 2} gas unit adsorption amount for the organic matter decomposition catalysts of Comparative Examples 11 to 14 is 1.

As shown in FIG. 14, the organic matter decomposition catalysts of Examples 1 to 8 satisfying the requirements of the present invention _{adsorb H 2} gas units after heat treatment at 800 ° C. as compared with the organic matter decomposition catalysts of Comparative Examples 11 to 14. The amount is large.

In the catalyst for organic substance decomposition that satisfies the requirements of the present invention, platinum nanoparticles that do not easily oxidize are supported on one surface of aluminum nitride contained in the carrier with a high degree of dispersion, so that the catalyst can be used in a high temperature environment such as 800 ° C. Even if it is used, it can suppress the oxidation of aluminum nitride. Therefore, since the thermal conductivity of aluminum nitride is maintained, heat dissipation proceeds even when the aluminum nitride is used in a high temperature environment, and the sintering of the supported platinum can be suppressed. Thereby, the decrease in the dispersity of platinum can be suppressed (sintering can be suppressed), and the decrease in the catalytic activity can be suppressed.

As described above, the average particle size of the platinum particles of the catalysts for organic matter decomposition of Examples 1 to 8 satisfying the requirements of the present invention is 28 nm or more and 41 nm or less. Therefore, in the catalyst for organic matter decomposition that satisfies the requirements of the present invention, it is preferable that the average particle size of platinum particles is 28 nm or more and 41 nm or less.

The present invention is not limited to the above embodiment, and various applications and modifications can be added within the scope of the present invention.

1 Carrier 2 Platinum 10 Catalyst for decomposition of organic matter

Claims (6)

1. A catalyst for decomposing organic matter used to decompose organic matter.
   With the carrier
   Platinum supported on the carrier and
   With
   The carrier is a catalyst for decomposition of organic substances, which comprises aluminum nitride having an atomic% ratio N / Al of N and Al present on the surface thereof of 0.40 or more and 0.50 or less.
2. The catalyst for organic matter decomposition according to claim 1, wherein the average particle size of the platinum is 28 nm or more and 41 nm or less.
3. When the _{amount of H 2 gas adsorbed on the organic substance decomposition catalyst is confirmed by introducing H 2} gas, the organic substance decomposition catalyst is adsorbed on the organic substance decomposition catalyst before and after the heat treatment at 800 ° C. The catalyst for organic substance decomposition according to claim 1 or 2, wherein the rate of decrease in the adsorption amount of the _{H 2 gas per mass of the platinum is 61% or more and 94% or less.}
4. When introducing the H ₂ gas was confirmed adsorption amount of H ₂ gas to be adsorbed to the organic material cracking catalyst, the platinum of the H ₂ gas to be adsorbed to the organic material cracking catalyst after heat treatment at 800 ° C. adsorption amount per mass, 0.46 cm ³ / g or more 1.61cm ³ / g organic decomposition catalyst according to any one of claims 1 to 3, wherein the less.
5. The catalyst for decomposing organic substances according to any one of claims 1 to 4, which is characterized by containing no chlorine.
6. An organic matter decomposition apparatus comprising the catalyst for organic matter decomposition according to any one of claims 1 to 5.

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