JP7269562B2 - Catalyst carrier and catalyst manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a highly active catalyst using a catalyst carrier on which a 12CaO.7Al ₂ O ₃ compound is immobilized.

Calcium aluminate having a 12CaO.7Al ₂ O ₃ structure is known to be useful as an oxidation catalyst, an ion conductor, and a co-catalyst because it has free oxygen in the lattice (Patent Documents 1 and 2). It is also known that this 12CaO.7Al ₂ O ₃ compound supports a transition metal such as Ni or Pt on its surface to obtain a catalyst for synthesizing ammonia, a catalyst for producing hydrogen from a hydrocarbon gas such as methane, and the like. (Patent Documents 3, 4, 5).

JP-A-2002-3218 JP-A-2006-96571 WO2012/077658 JP 2018-143940 A JP 2018-143941 A

However, most of the catalysts currently in practical use in industry, including those for environmental purification and automobile use, are not used in the form of powder, but are carried on various supports. The reason for this is that the powder causes clogging, which makes it difficult for the gas to flow, and there is concern about the environmental impact due to scattering. Therefore, it is desired that the catalyst of the present invention is also supported on a support or the like before use. However, a sufficient study has not been made on a technique for supporting fine particles of 12CaO.7Al ₂ O ₃ compound on a support. Accordingly, an object of the present invention is to provide a method for producing a catalyst carrier in which a 12CaO.7Al ₂ O ₃ compound having a large specific surface area is efficiently immobilized on a ceramics carrier.

When the 12CaO.7Al ₂ O ₃ compound is supported on the ceramic support, the 12CaO.7Al ₂ O ₃ compound particles are dispersed in an organic solvent to prevent the hydration reaction of the 12CaO.7Al ₂ O ₃ compound. I tried coating it on my body. However, in this method, the compatibility between the ceramic support and the organic solvent was poor, and the 12CaO.7Al ₂ O ₃ compound particles did not adhere and most of the particles were easily peeled off (see FIG. 1). As a solution to this problem, after coating the surface of a ceramic support with an aqueous slurry in which only the surface layer of the 12CaO·7Al ₂ O ₃ compound is hydrated, the support is heated to 400 to 1000°C. Calcium aluminate hydrate adhering to the transition metal is regenerated into a 12CaO.7Al ₂ O ₃ compound, and a catalyst carrier in which the 12CaO.7Al ₂ O ₃ compound having a high specific surface area is immobilized on the support is obtained. The present inventors have completed the present invention by finding that a catalyst having excellent catalytic activity can be obtained by supporting

That is, the present invention provides the following [1] to [7].

[1] (A) a step of coating the surface of a ceramic support with an aqueous slurry in which particles containing calcium aluminate hydrate are dispersed;
(B) A method for producing a catalyst carrier, comprising the step of heat-treating the ceramic support at a temperature of 400 to 1000° C. to generate 12CaO.7Al ₂ O ₃ compound particles on the ceramic support and immobilizing them.
[2] The method for producing a catalyst carrier according to [1], wherein the particles containing calcium aluminate hydrate are particles in which calcium aluminate hydrate is formed on the surface of 12CaO·7Al ₂ O ₃ compound particles. .
[3] The aqueous slurry in which the particles containing calcium aluminate hydrate are dispersed is an aqueous slurry obtained by dispersing 12CaO.7Al ₂ O ₃ compound particles in water [1] or [2]. A method for producing a catalyst carrier.
[4] The method for producing a catalyst carrier according to [2] or [3], wherein the 12CaO.7Al ₂ O ₃ compound particles have a BET specific surface area of 3 m ² /g or more.
[5] The method for producing a catalyst carrier according to any one of [1] to [4], wherein the ceramic support has a honeycomb structure.
[6] Further, (C) a step of supporting a transition metal on the 12CaO.7Al ₂ O ₃ compound particles on the ceramic support of the catalyst carrier according to any one of [1] to [5]. Method.
[7] In the step (C), the 12CaO.7Al ₂ O ₃ compound particles on the ceramic support are treated with a dispersion of transition metal fine particles of 0.001 μm or more and 1 μm or less or a transition metal salt solution. A method for producing a catalyst according to [6].

According to the method of the present invention, the 12CaO.7Al ₂ O ₃ compound adheres well to the ceramic support, and a catalyst carrier in which the 12CaO.7Al ₂ O ₃ compound having a large specific surface area is immobilized on the support is obtained. is obtained, the co-catalyst performance of the obtained catalyst carrier is also enhanced. By supporting a transition metal on the surface of the supported 12CaO.7Al ₂ O ₃ compound layer, industrially useful oxidation catalysts, reduction catalysts and catalysts for cracking hydrocarbons can be obtained.

The adhesion to the cordierite ceramic support surface and scanning electron microscope images are shown. 12 shows changes in crystal structure depending on contact time with water when fine particles of 12CaO.7Al ₂ O ₃ compound are dispersed in water. It shows the change of crystal structure due to coating treatment using aqueous slurry and heat treatment temperature. FIG. 2 shows a conceptual diagram of improving adhesion to a support by coating treatment using an aqueous slurry and heat treatment. The results of evaluation of the promoter effect of 12CaO.7Al ₂ O ₃ compound by dispersion treatment in water and heat treatment using temperature-rising reaction method are shown.

The method for producing the catalyst of the present invention comprises (A) the step of coating the surface of a ceramic support with an aqueous slurry in which particles containing calcium aluminate hydrate are dispersed;
(B) heat-treating the ceramic support at a temperature of 400 to 1000° C. to generate 12CaO.7Al ₂ O ₃ compound particles on the ceramic support and immobilizing them.

Particles containing calcium aluminate hydrate used in step ₍ A) may be calcium aluminate particles in which calcium aluminate _hydrate is present on the particle surface. Particles in which calcium aluminate hydrate is formed are preferred. Here, the calcium aluminate hydrate preferably contains a hydrate that regenerates a 12CaO.7Al ₂ O ₃ compound by heat treatment, such as Ca ₃ Al ₂ O ₆ .xH ₂ O and Ca ₂ Al ₂ O _{5 .} * _xH2O , _{Ca4Al2O7 * xH2O} etc. are mentioned _.

Here, the 12CaO.7Al ₂ O ₃ compound is calcium aluminate having a 12CaO.7Al ₂ O ₃ structure, and can be produced, for example, by heating a mixture of a calcium compound and an aluminum compound.

Calcium oxide, calcium carbonate, etc. are mentioned as a calcium compound used as a raw material. The aluminum compound includes aluminum oxide, and the crystal structure of aluminum oxide may be either α-type or γ-type. Further, these calcium compounds and aluminum compounds may be in any form, such as powder, solid sintered product, solid single crystal, and the like. The mixing ratio of the raw materials is preferably 1.5 or more and 1.9 or less, more preferably 1.6 or more and 1.8 or less, in terms of oxide equivalent molar ratio [(CaO)/(Al ₂ O ₃ )].

The mixture of the calcium compound and the aluminum compound can be heated in a vacuum, an inert gas atmosphere, a hydrogen atmosphere, an oxygen atmosphere, or the like. However, an atmosphere containing water vapor is not preferable. It can also be carried out in dry air with an oxygen concentration of about 21%. In the case of heating and manufacturing in an oxygen atmosphere, it is preferable to set the mixing ratio of the raw materials to a molar ratio [(CaO)/(Al ₂ O ₃ )] in the range of 1.5 or more and 1.7 or less. It is preferable from the viewpoint of obtaining a 12CaO.7Al ₂ O ₃ compound.
As for the heating conditions, the maximum temperature is preferably the temperature at which the raw material compounds react to form calcium aluminate or higher, more preferably 1250° C. or higher and 2500° C. or lower, and 1300° C. or higher and 1800° C. or lower. More preferred. When the raw material compound is melted to produce the 12CaO.7Al ₂ O ₃ compound, the temperature is preferably 1400° C. or higher.

By heating to the above temperature, the raw material compound reacts to form a 12CaO.7Al ₂ O ₃ compound, which is pulverized as necessary to obtain fine particles of the 12CaO.7Al ₂ O ₃ compound. When it is melted, it is cooled to form a solidified product, and the obtained solidified product is pulverized to obtain 12CaO.7Al ₂ O ₃ compound fine particles.
The cooling conditions are not particularly limited, but in the case of melting, the temperature drop rate is preferably 50° C./hour or more and 600° C./hour or less until the temperature after melting reaches 1200° C. or less.
The 12CaO.7Al ₂ O ₃ compound produced may be either crystalline or vitreous. The 12CaO.7Al ₂ O ₃ compound _has a purity _of 50% or more and may contain other calcium aluminate compounds. It is preferably 80% or more, more preferably 90% or more.
For the pulverization step of the solidified 12CaO.7Al ₂ O ₃ compound, either dry pulverization or wet pulverization using an organic solvent to prevent hydration of the 12CaO.7Al ₂ O ₃ compound can be used. . The fine particles to be obtained are preferably fine powder having a BET specific surface area of 2 m ² /g or more from the viewpoint of dispersion in aqueous slurry.

The aqueous slurry in which particles containing calcium aneminate hydrate in step (A) are dispersed is an aqueous slurry obtained by dispersing the 12CaO.7Al ₂ O ₃ compound particles obtained as described above in water. is preferred. The slurry is preferably obtained by adding and mixing 12CaO.7Al ₂ O ₃ compound in an amount of preferably 0.1 to 30 parts by mass, more preferably 1 to 10 parts by mass, with respect to 100 parts by mass of water. Here, the preparation temperature of the aqueous slurry may be 0.1°C to 30°C.
By dispersing the 12CaO·7Al ₂ O ₃ compound particles in water to form an aqueous slurry, calcium aluminate hydrate is formed on the surfaces of the 12CaO·7Al ₂ O ₃ compound particles. Here, as a method for dispersing in water, it is preferable to slowly stir with a weak force using a stirrer using a stirring blade, a stirrer, or the like. Since it is sufficient if the surface of the 12CaO.7Al ₂ O ₃ compound particles is hydrated and a layer of calcium aluminate hydrate is formed on the surface of the 12CaO.7Al ₂ O ₃ compound particles, an unnecessarily strong force is applied. It is not necessary to stir and mix with , and it is not preferable to prepare an aqueous slurry by wet pulverization. The contact time with water (stirring time) is not particularly limited, but is preferably 1 to 120 minutes, more preferably 5 to 90 minutes.
The BET specific surface area of the obtained particles containing calcium aluminate hydrate is preferably 5 m ² /g or more, more preferably 10 m ² /g or more, and even more preferably 100 m ² /g or more.
The aqueous slurry is coated on the surface of the ceramic support. Here, ceramic supports include ceramic pellets, ceramic foams, ceramic honeycombs, plugging _{type ceramic} honeycombs, and the like. A ceramic support is more preferred. Examples of ceramics include silicon carbide, cordierite, mullite, alumina, zirconia, titania, titanium phosphate, aluminum titanate, and aluminosilicate. In addition, the ceramic support in the present invention includes those whose surfaces have the properties of ceramics. For example, it is possible to use metals such as iron, aluminum, chromium, titanium, and alloys thereof, on which a passivated film of ceramics such as metal oxides is formed.

In order to coat the aqueous slurry on the surface of the ceramic support, the aqueous slurry may be brought into contact with the surface of the ceramic support. Specific examples include a method of coating or spraying the aqueous slurry onto the ceramic support, or a method of immersing the ceramic support in the aqueous slurry. About 10 seconds is sufficient for the immersion. The immersion temperature is preferably 0.1 to 30°C. The number of times of immersion is preferably multiple times, but regardless of the number of times of immersion including once, the 12CaO.7Al ₂ O ₃ compound particles are present on the surface of the support after the heat treatment in step (B). All you have to do is

According to such step (A), the adhesion rate of calcium aluminate to the ceramic support becomes extremely high.

Next, the ceramic support whose surface is coated with the aqueous slurry is heat-treated at a temperature of 400 to 1000° C. to generate and immobilize 12CaO.7Al ₂ O ₃ compound particles on the ceramic support (step (B)). .

The heat treatment of _the ceramic support converts the calcium aluminate hydrate into a 12CaO.7Al.sub.2O.sub.3 compound and improves the specific surface area of _{the obtained 12CaO.7Al.sub.2O.sub.3} compound particles. °C, preferably 400 to 900°C, more preferably 450 to 800°C, even more preferably 450 to 700°C, even more preferably 450 to 600°C. The heat treatment time is not particularly limited as long as the calcium aluminate hydrate is changed to the 12CaO.7Al ₂ O ₃ compound, but about 60 minutes is sufficient.
By the heat treatment, new 12CaO.7Al ₂ O ₃ compound particles are generated and immobilized on the ceramic support. Here, the newly generated 12CaO.7Al ₂ O ₃ compound particles have a form in which a new fine 12CaO.7Al ₂ O ₃ aggregate layer is formed on the surface layer of the 12CaO.7Al ₂ O ₃ compound core portion. It is preferable to be The BET specific surface area of the 12CaO.7Al ₂ O ₃ compound particles is preferably 3 m ² /g or more, more preferably 5 m ² /g or more. Moreover, the upper limit of the BET specific surface area of the 12CaO.7Al ₂ O ₃ compound particles is preferably 50 m ² /g or less.

According to the step (B), the 12CaO.7Al ₂ O ₃ compound particles are fixed on the ceramic support at a high rate, are not easily peeled off, and are particularly excellent as a catalyst support (having co-catalyst performance). there is

The resulting 12CaO.7Al ₂ O ₃ compound particles immobilized on the ceramic support can further support transition metals having various catalytic activities.
Examples of transition metals include one or more elements selected from Groups 8, 9 and 10 such as Ni, Pt, Pd, Ru, Rh and Co. For example, a heterogeneous catalyst such as a binary system or a ternary system may be used. These transition metals can be selected according to the desired catalytic activity. For example, in the case of hydrogen production catalysts, Ni, Pt, Pd, Ru and Rh are more preferable, and Pt is particularly preferable.
The particle size of the transition metal is preferably small from the viewpoint of catalytic activity and securing a high degree of dispersion on the surface of the catalyst support. The following are more preferable, and 0.001 μm or more and 0.01 μm or less are even more preferable. Here, the median diameter is the particle size value at which the cumulative frequency by the dynamic light scattering method is 50%.

A transition metal can be supported on a catalyst carrier in which 12CaO.7Al ₂ O ₃ compound particles are immobilized on a ceramic support, for example, by an impregnation method using an organic solvent. Specifically, after the catalyst carrier is put into a dispersion of the transition metal in an organic solvent such as hexane, the mixture is stirred to evaporate the solvent. Here, the supported amount of the transition metal is preferably 0.1 to 40% by mass, more preferably 1 to 20% by mass, relative to the catalyst carrier.

According to the method of the present invention, the adhesion of the 12CaO.7Al ₂ O ₃ compound particles on the ceramic support is improved, the specific surface area is increased, and the fixation property is improved without peeling off. . Therefore, it is practically important to simultaneously realize an increase in the co-catalyst performance of the 12CaO.7Al ₂ O ₃ compound. By supporting a metal catalyst such as Ni or Pt according to the purpose on the surface of the coated film, pellet-type or honeycomb-type functional catalysts having the co-catalytic action of the 12CaO 7Al ₂ O ₃ compound can be produced. , the expansion of the application range can be expected by being able to be used in industrial practical sites. An example of its application is the direct decomposition of methane to produce hydrogen. This method does not emit _CO2 and produces carbon. Accumulation, easy to remove by vibration, air blow, etc.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1
(Preparation of 12CaO.7Al ₂ O ₃ compound fine particles)
A mixed powder in which the molar ratio of calcium oxide and α-type aluminum oxide is [(CaO)/(Al ₂ O ₃ )]=1.63 is placed in a magnesium oxide crucible, and heated at a rate of 400 in dry air having an oxygen concentration of 21%. C./hr to 1440.degree. C., held in a molten state for 3 hours, and _slowly cooled to room temperature at a cooling rate of _150.degree . A jet mill pulverization method was used for fine pulverization, and Nano Jet Mizer NJ-50-C type (manufactured by Aisin Nano Technologies Co., Ltd.) was used. At this time, the specific surface area of the obtained 12CaO.7Al ₂ O ₃ compound fine particles was 2.1 m ² /g. The specific surface area was calculated as a BET specific surface area using an N ₂ gas adsorption measuring device (BELsorp MAX manufactured by Microtrack Bell Co., Ltd.).

(Coating treatment with aqueous slurry)
2 parts by mass of the resulting 12CaO.7Al ₂ O ₃ compound fine particles were added to 100 parts by mass of distilled water, and the mixture was stirred for 1 hour to prepare an aqueous slurry. A honeycomb type cordierite having a mesh size of 400 per square inch was used as the support, and a honeycomb surface of 3 cm×3 cm in the vertical direction and 5 cm in the horizontal direction was cut out and used. This honeycomb support (3 cm×5 cmH) was immersed in the aqueous slurry for 10 seconds, dried at 100° C. for 1 hour in the air, then immersed again in the aqueous slurry for 10 seconds, and heated at 500° C. for 1 hour in the air. A catalyst carrier was prepared by carrying 12CaO.7Al ₂ O ₃ compound fine particles on a honeycomb support after heat treatment. The obtained catalyst carrier was immersed in an ultrasonic cleaner containing distilled water and subjected to _ultrasonic vibration at a frequency of 40 kHz for 1 _minute . As a result, it was 5% or less.

(Preparation of Ni catalyst)
The obtained catalyst carrier was immersed in a liquid in which 5% by mass of Ni was dispersed in hexane for 10 seconds, heat-treated at 400°C for 1 hour in an air atmosphere, and then heat-treated at 400°C for 1 hour in a hydrogen atmosphere. A Ni catalyst was produced.

(Evaluation of catalyst performance by direct methane decomposition reaction)
Methane gas was flowed at 4.5 L/hr while the Ni catalyst was heated to 700° C. in a flow-type reaction tube, and the hydrogen generation characteristics at that time were measured by gas chromatography. As a result, the methane conversion rate was 37.4% and the hydrogen concentration was 53.6% at the initial stage of methane flow.

Example 2
(Coating treatment with aqueous slurry)
A honeycomb support (3 cm×5 cmH) prepared in the same manner as in Example 1 was immersed in an aqueous slurry for 10 seconds, dried at 100° C. for 1 hour in an air atmosphere, and then immersed again in the aqueous slurry for 10 seconds. A catalyst carrier was prepared by carrying out a heat treatment at 800° C. for 1 hour in an air atmosphere to carry 12CaO.7Al ₂ O ₃ compound fine particles on a honeycomb support.

(Preparation of Ni catalyst)
The obtained catalyst carrier was immersed in a liquid in which 5% by mass of Ni was dispersed in hexane for 10 seconds, heat-treated at 400°C for 1 hour in an air atmosphere, and then heat-treated at 400°C for 1 hour in a hydrogen atmosphere. A Ni catalyst was produced.

(Evaluation of catalyst performance by direct methane decomposition reaction)
Methane gas was flowed at 4.5 L/hr while the Ni catalyst was heated to 700° C. in a flow-type reaction tube, and the hydrogen generation characteristics at that time were measured by gas chromatography. As a result, the methane conversion rate was 31.1% and the hydrogen concentration was 46.0% at the initial stage of methane flow.

Comparative example 1
2% by mass of 12CaO.7Al ₂ O ₃ compound fine particles obtained in the same manner as in Example 1 were added to hexane, and the mixture was stirred for 5 minutes to prepare a slurry. A honeycomb support (3 cm×5 cmH) was immersed in this slurry for 10 seconds, dried at 100° C. for 1 hour in an air atmosphere, then immersed in the slurry again for 10 seconds, and heat-treated at 500° C. for 1 hour in an air atmosphere. A catalyst carrier was prepared by carrying 12CaO.7Al ₂ O ₃ compound fine particles on a honeycomb support. The obtained catalyst carrier was immersed in an ultrasonic cleaner containing distilled water and subjected to _ultrasonic vibration at a frequency of 40 kHz for 1 _minute . As a result, it was 90% or more, and it was difficult to stably coat the fine particles of the 12CaO.7Al ₂ O ₃ compound.

Comparative example 2
(Preparation of Ni catalyst)
12CaO.7Al ₂ O ₃ compound fine particles obtained in the same manner as in Example 1 were stirred in a liquid in which 5% by mass of Ni was dispersed in hexane, and the solvent was volatilized. After the time heat treatment, heat treatment was performed in a hydrogen atmosphere at 400° C. for 1 hour to prepare a powdered Ni catalyst.

(Evaluation of catalyst performance by direct methane decomposition reaction)
Methane gas was flowed at 4.5 L/hr while the Ni catalyst was heated to 700° C. in a flow-type reaction tube, and the hydrogen generation characteristics at that time were measured by gas chromatography. As a result, the methane conversion rate was 26.2% and the hydrogen concentration was 25.3% at the initial stage of methane circulation.

Reference example 1
In order to clarify the changes in the physical properties of the 12CaO 7Al ₂ O ₃ compound due to the coating treatment using an aqueous slurry and the heat treatment, the crystal structure and specific surface area were analyzed using an X-ray diffractometer (SmartLab manufactured by Rigaku Co., Ltd.) and N ₂ gas adsorption. Analysis was performed using a measurement device (BELsorp MAX manufactured by Microtrack Bell Co., Ltd.).

FIG. 2 shows the change in the crystal structure according to the contact time with water when the 12CaO.7Al ₂ O ₃ compound fine particles after the jet mill pulverization treatment used in each example and comparative example were stirred in distilled water. are shown in Table 1. The crystal structure changed at the point of contact time of 5 minutes, and the spectrum of calcium aluminate hydrate was confirmed in addition to the 12CaO.7Al ₂ O ₃ compound. I didn't. The specific surface area increased with increasing contact time with water.

FIG. 3 shows changes in the crystal structure of the 12CaO.7Al ₂ O ₃ compound fine particles according to the heat treatment temperature after stirring them in distilled water for 1 hour, and Table 2 shows changes in the specific surface area. It can be confirmed from FIG. 3 that the spectrum of the calcium aluminate hydrate disappeared and the spectrum of the 12CaO.7Al ₂ O ₃ compound grew by heat treatment at 500° C. and 800° C. FIG. In addition, as shown in Table 2, the specific surface area decreased due to the heat treatment after stirring in water, but the coating treatment with the aqueous slurry resulted in a larger specific surface area than the jet mill pulverization treatment alone (no contact with water). became.

FIG. 4 shows a conceptual diagram of coating treatment using an aqueous slurry and improvement of adhesion to a support by heat treatment. As shown in Reference Example 1, it is presumed that calcium aluminate hydrate is produced during preparation of the aqueous slurry, forming a bond with the support via hydroxyl groups. Therefore, it is considered that the subsequent heat treatment results in immobilization on the support.

Reference example 2
In order to clarify the change in the promoter effect of 12CaO.7Al ₂ O ₃ compound fine particles due to dispersion treatment in water and heat treatment, the reaction temperature at the time of complete combustion of organic compound gas (ethanol) is measured by the temperature programmed reaction method. It was indirectly evaluated by Specifically, a sample (0.2 g) is packed in a flow reaction tube, and the temperature is gradually increased (3 ° C./min) while flowing dry air (100 mL / min) containing about 500 ppm ethanol, and the residual The gas chromatograph installed on the outlet side was used to measure the organic substances present and the carbon dioxide generated by the combustion of ethanol.

FIG. 5 shows the evaluation results of the co-catalyst effect of the 12CaO.7Al ₂ O ₃ compound by dispersion treatment in water and heat treatment using the temperature-rising reaction method. The horizontal axis is the reaction temperature, and the vertical axis is the carbon dioxide concentration. Normally, the decomposition temperature of methanol is about 800°C, but the decomposition initiation temperature of methanol was lowered to about 350°C by using the fine particles of 12CaO.7Al ₂ O ₃ compound after pulverization by a jet mill as a catalyst. Further, when the 12CaO.7Al ₂ O ₃ compound fine particles were stirred in water for 30 minutes and heat-treated at 800°C, the decomposition initiation temperature further decreased to about 300°C. From this, it was confirmed that the co-catalyst effect of the 12CaO.7Al ₂ O ₃ compound fine particles is improved by dispersion treatment in water and heat treatment.

Claims (5)

(A) 12CaO·7Al ₂ O ₃ compound particles are dispersed in water for 1 to 120 minutes to form an aqueous slurry, thereby forming calcium aluminate hydrate on the surface of the 12CaO·7Al ₂ O ₃ compound particles. After that, a step of coating the surface of the ceramic support with an aqueous slurry in which particles containing the calcium aluminate hydrate are dispersed;
(B) heat-treating the ceramic support at a temperature of 500 to 800° C. to form 12CaO.7Al ₂ O ₃ compound particles on the ceramic support and immobilizing them. Production method. 2. The method for producing a hydrocarbon cracking catalyst carrier according to claim 1 , wherein the 12CaO.7Al ₂ O ₃ compound particles after the heat treatment have a BET specific surface area of 3 m ² /g or more. 3. The method for producing a hydrocarbon cracking catalyst carrier according to claim 1 , wherein the ceramic support has a honeycomb structure. Further, (C) production of a hydrocarbon cracking catalyst comprising the step of supporting a transition metal on the 12CaO.7Al ₂ O ₃ compound particles on the ceramic support of the catalyst carrier according to any one of claims 1 to 3 . Method. The step (C) is a step of treating the 12CaO.7Al ₂ O ₃ compound particles on the ceramic support with a dispersion of transition metal fine particles of 0.001 μm or more and 1 μm or less or a transition metal salt solution. Item 5. A method for producing a hydrocarbon cracking catalyst according to item 4 .

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