JP6349157B2 - Composition for gas combustion catalyst, method for producing support including catalyst layer, and gas combustion catalyst - Google Patents

Description

  The present invention relates to a composition for a gas combustion catalyst, a method for producing a support including a catalyst layer, and a gas combustion catalyst.

  Catalysts for combustion of gases such as hydrogen, hydrocarbons and carbon monoxide are widely known. For example, Patent Literature 1 discloses a hydrogen combustion catalyst for burning hydrogen in exhaust gas at a hydrogen production plant or the like. In this hydrogen combustion catalyst, a catalyst metal is supported on a carrier having a washcoat layer. The washcoat layer is composed of zirconia and tungsten oxide having a plurality of crystal structures. Thereby, even if it uses for a long period of time, it becomes difficult for the activity of a catalyst to fall.

  Patent Document 2 discloses a hydrogen combustion catalyst in which a catalyst metal is supported on a support made of an inorganic oxide. The hydroxyl group on the surface of the carrier is modified with a predetermined functional group. Thereby, even when the reaction at a low temperature is required, a decrease in activity due to adsorption of the produced water to the catalyst is prevented.

  Patent Document 3 describes a thermoelectric power generation device that converts a local temperature difference generated by heat accompanying combustion of combustible gas fuel using a catalyst into electrical energy using a thermoelectric conversion material. A paste-like functional material is prepared by mixing a catalyst powder of oxide such as alumina or tin oxide in which a noble metal is dispersed with a vehicle. This pasty functional material is applied to a predetermined position using a dispenser to form a fine pattern. Patent Document 4 discloses a method for forming such a fine pattern.

JP 2013-27811 A JP2011-139991A JP 2012-105512 A JP 2006-47276 A

  In order to form the catalyst layer of the gas combustion catalyst on the support, it is conceivable to prepare a gas combustion catalyst composition having fluidity. In this case, the gas combustion catalyst composition desirably contains a component that improves the adhesion of the catalyst layer to the support. However, Patent Documents 1 to 4 do not specifically examine the components to be included in the gas combustion catalyst composition in order to improve the adhesion of the catalyst layer to the support.

  Then, an object of this invention is to provide the composition for gas combustion catalysts suitable for forming the catalyst layer with high adhesiveness to a support body on a support body.

  Moreover, this invention aims at providing the manufacturing method of the support body containing a catalyst layer using such a composition for gas combustion catalysts.

  Another object of the present invention is to provide a gas combustion catalyst that is desirable as a catalyst to be included in such a composition for gas combustion catalyst.

The present invention
A metal comprising an element belonging to Group 7 to Group 11 of the periodic table and / or an alloy containing the metal, and a support which is a metal oxide supporting the metal or the alloy, and has a BET specific surface area. A catalyst that is 30 m ² / g or more;
Boehmite particles,
A polar solvent,
A composition for a gas combustion catalyst is provided.

The present invention
Applying the composition for gas combustion catalyst to a support;
Removing the polar solvent from the composition for gas combustion catalyst applied to the support to form a catalyst layer, and
A method for producing a support including a catalyst layer is provided.

The present invention
A metal comprising an element belonging to Group 7 to Group 11 of the periodic table and / or an alloy containing the metal;
A support that is a metal oxide carrying the metal or the alloy,
BET specific surface area is 30 m ² / g or more,
A gas combustion catalyst is provided.

  According to the present invention, the adhesion of the catalyst layer to the support can be improved.

Field-emission scanning electron micrograph of the dried product obtained by drying the catalyst carrier material The figure which shows the X-ray-diffraction pattern of the dried material which dried the raw material of the support | carrier of a catalyst The figure which shows the X-ray-diffraction pattern of the catalyst which concerns on an Example. The figure which shows the X-ray-diffraction pattern of the boehmite particle which concerns on an Example. The figure which shows the X-ray-diffraction pattern of the catalyst which concerns on an Example. The figure which shows the X-ray-diffraction pattern of the catalyst which concerns on an Example. The figure which shows the X-ray-diffraction pattern of the catalyst which concerns on an Example. The figure which shows the X-ray-diffraction pattern of the boehmite particle which concerns on an Example. The figure which shows the X-ray-diffraction pattern of the catalyst which concerns on a comparative example

  Hereinafter, embodiments of the present invention will be described. The following description relates to an example of the present invention, and the present invention is not limited thereto.

The composition for gas combustion catalyst of the present invention contains a catalyst, boehmite particles, and a polar solvent. The catalyst exhibits a catalytic action for combustion of a predetermined gas. The catalyst is catalytic for the combustion of, for example, hydrogen, carbon monoxide, hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, or amines. The catalyst includes a metal and / or alloy and a support. The metal contained in the catalyst is a metal composed of elements belonging to Group 7 to Group 11 of the periodic table. Moreover, the alloy contained in the catalyst is an alloy containing a metal composed of an element belonging to Group 7 to Group 11 of the periodic table. The support is a metal oxide carrying the metal or alloy. Further, the BET specific surface area of the catalyst is 30 m ² / g or more. In the gas combustion catalyst composition, the boehmite particles coexist with a catalyst having a predetermined BET specific surface area, whereby the catalyst layer formed by applying the gas combustion catalyst composition to the support is applied to the support. Adhesion is improved. That is, the boehmite particles exhibit desirable characteristics as a binder component in the gas combustion catalyst composition.

When the BET specific surface area of the catalyst is large, the adhesion of the catalyst layer to the support is improved. In addition, the activity of the catalyst is improved. From this viewpoint, the BET specific surface area of the catalyst is desirably 50 m ² / g or more, more desirably 70 m ² / g or more, further desirably 90 m ² / g or more, and particularly desirably 100 m ² / g. That's it.

  The element belonging to Group 7 to Group 11 of the periodic table is, for example, at least one element selected from the group consisting of Ru, Rh, Ir, Pd, Pt, Ag, and Au. Ru, for example, exhibits a catalytic action on the combustion of carbon monoxide. Rh exhibits, for example, a catalytic action for hydrogen combustion. Ir exhibits, for example, a catalytic action for the combustion of carbon monoxide. Pd exhibits a catalytic action for combustion of hydrocarbons such as methane. Pt exhibits, for example, catalytic action for hydrogen combustion. Ag shows a catalytic action with respect to combustion of carbon monoxide, for example. Au, for example, exhibits a catalytic action on the combustion of carbon monoxide. Examples of alloys included in the catalyst include Pt—Ru alloy, Pt—Rh alloy, Pt—Pd alloy, Pt—Ir alloy, Pt—Au alloy, Pt—Sn alloy, Pt—Re alloy, Pd—Au alloy, Rh-Au alloy and Au-Cu alloy can be mentioned.

  When the crystallite diameter of the metal or alloy is within a predetermined range, the BET specific surface area of the catalyst is increased. In addition, since the metal or alloy particles are supported on the support without being excessively agglomerated, the catalytic activity can be enhanced. From this viewpoint, the crystallite diameter of the metal or alloy contained in the catalyst is, for example, 30 nm or less, desirably 20 nm or less, more desirably 15 nm or less, and further desirably 10 nm or less. The lower limit of the crystallite diameter of the metal or alloy contained in the catalyst is not particularly limited, but is 0.5 nm, for example. The crystallite diameter can be measured using a known analysis method such as the Scherrer method.

  The amount of the metal or alloy supported on the carrier is not particularly limited, but it is better that the amount of the metal or alloy supported is larger in order to increase the activity of the catalyst. On the other hand, from the viewpoint of increasing the dispersibility of the metal or alloy and preventing an increase in the amount of the metal or alloy that does not contribute to the activity, it is desirable that the amount of the metal or alloy supported on the support is not more than a predetermined value. For this reason, the loading ratio of the metal or alloy in the catalyst is, for example, 0.5% by mass or more and 60% by mass or less, desirably 1% by mass or more and 50% by mass or less, and more desirably 2% by mass or more and 40% by mass or less. The content is 3% by mass or less, more preferably 3% by mass or more and 30% by mass or less, and particularly preferably 4% by mass or more and 20% by mass or less. Here, the loading rate of the metal or alloy in the catalyst is defined as the ratio of the mass of the catalyst to the mass of the supported metal or alloy.

  The carrier is, for example, an oxide particle of at least one element selected from the group consisting of Y, Ce, Ti, Zr, Nb, W, Fe, Zn, Al, Si, and Sn. That is, the carrier is, for example, particles of at least one oxide selected from the group consisting of yttria, ceria, titania, zirconia, niobium oxide, tungsten oxide, iron oxide, zinc oxide, alumina, silica, and tin oxide. Among these, it is desirable to use alumina (γ-alumina) particles having a γ-type crystal structure as a carrier. This is because γ-alumina has a large effect of increasing the BET specific surface area of the catalyst and improving the adhesion of the catalyst layer to the support. The catalyst may contain one kind of oxide as a support, or may contain two or more oxides as a support.

  From the viewpoint of improving the adhesion of the catalyst layer to the support, the carrier preferably has a rod shape. This is because, when the carrier is in the rod shape, the catalyst is liable to come into contact with each other, and the contact ratio with the support increases. The shape of the carrier is, for example, a rod shape having a short axis length of 5 to 30 nm, a long axis length of 20 to 1000 nm, and an aspect ratio of 2 to 200. For example, when the carrier is γ-alumina, a boehmite nanorod dispersion can be used as a raw material for the carrier having such a rod shape. Specifically, a dispersion of boehmite nanorods having a rod shape having a minor axis length of 5 to 30 nm, a major axis length of 20 to 1000 nm, and an aspect ratio of 2 to 200 can be used as a raw material for the carrier. . Such a dispersion of boehmite nanorods can be prepared, for example, by the following method.

  First, a solution containing aluminum carboxylate or aluminum β-diketone complex and water and substantially free of alkali metal elements and alkaline earth metal elements is prepared. In some cases, a carboxylic acid such as acetic acid may be added to this solution. Next, this solution is hydrothermally treated at a temperature of 100 ° C to 300 ° C. Thereby, a dispersion of boehmite nanorods as a raw material for the carrier can be obtained.

  As described above, in the gas combustion catalyst composition, the coexistence of the catalyst and boehmite particles can enhance the adhesion of the catalyst layer formed by applying the gas combustion catalyst composition to the support. The crystallite size of the boehmite particles is not particularly limited, but is, for example, 20 nm or less. The ratio Wb / Wc of the mass Wb of the boehmite particles to the mass Wc of the catalyst in the gas combustion catalyst composition is not particularly limited. Since boehmite particles improve the adhesion of the catalyst layer to the support when the catalyst layer is formed on the support using the composition for gas combustion catalyst, the boehmite particles are more than a predetermined ratio in the composition for gas combustion catalyst. It is desirable to be included. From this viewpoint, Wb / Wc in the composition for gas combustion catalyst is, for example, 0.01 or more, preferably 0.02 or more, and more preferably 0.05 or more. In order to ensure the activity of the catalyst, it is desirable that boehmite particles are contained in the gas combustion catalyst composition in a predetermined ratio or less. From this viewpoint, Wb / Wc is, for example, 1 or less, desirably 0.5 or less, and more desirably 0.3 or less.

  The polar solvent is not particularly limited as long as the catalyst and boehmite particles can be dispersed in the gas combustion catalyst composition. The polar solvent is, for example, water or alcohols. Examples of polar solvents include water, methanol, ethanol, n-propanol, isopropanol, n-butyl alcohol, tert-butyl alcohol, n-pentyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, n- Nonyl alcohol, 1-decanol, 1-dodecanol, 2-ethylhexanol, phenol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, dimethyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, phenyl cellosolve, glycerin, and terpineol can be exemplified .

  Next, an example of the manufacturing method of the composition for gas combustion catalysts is demonstrated. First, a carrier or carrier precursor powder or a dispersion in which these are dispersed is prepared, and this is mixed with a metal or alloy dispersion or a metal salt solution. The solvent is removed from the mixture to obtain a solid. Examples of the dispersion of the metal or alloy include, for example, a polymer such as polyvinylpyrrolidone (PVP), polyethyleneimine (PEI), or polyacrylic acid (PAA), or a dispersant such as tetramethylammonium (TMA). A colloidal solution in which particles are stably dispersed can be used. As the metal salt solution, a metal organic salt solution or a metal inorganic salt solution can be used. In order to increase the activity of the catalyst by reducing the crystallite diameter of the metal or alloy in the catalyst, it is desirable to use a colloidal liquid of the metal or alloy. Even when a metal salt solution is used, it is desirable to use a metal salt containing no halogen element such as chlorine, in order to increase the activity of the catalyst by reducing the crystallite diameter of the metal or alloy in the catalyst. It is desirable to use a solution in which the metal salt is an organic salt.

  Next, the solid material obtained as described above is fired and pulverized. Thereby, catalyst powder is obtained. The firing temperature and firing time are not particularly limited. The firing temperature is, for example, 200 to 600 ° C., and the firing time is, for example, 0.1 hour to 5 hours.

  Next, the catalyst powder is added to a sol solution in which boehmite particles are dispersed in a polar solvent. That is, such a sol liquid is supplied as a binder component of the composition for gas combustion catalyst. The sol solution to which the catalyst powder is added is stirred to disperse the catalyst in a polar solvent. Thereby, the composition for gas combustion catalysts of this embodiment can be obtained. The stirring time for dispersing the catalyst in the polar solvent is not particularly limited, and is, for example, 1 to 120 minutes. Instead of using a sol solution in which boehmite particles are dispersed in a polar solvent, the catalyst powder and boehmite particle powder are polarized by adding the catalyst powder and boehmite particle powder to the polar solvent and then stirring. A composition for gas combustion catalyst may be obtained by dispersing in a solvent.

  Next, the manufacturing method of the support body containing a catalyst layer is demonstrated. The support including the catalyst layer includes a step of applying the gas combustion catalyst composition obtained as described above to the support, and removing the polar solvent from the gas combustion catalyst composition applied to the support. And a step of forming a catalyst layer. The support is not particularly limited, and examples thereof include a semiconductor substrate such as a Si substrate with a thermal oxide film, a metal support, a ceramic support, a glass substrate, and a resin substrate. The shape of the support is not particularly limited, and examples thereof include a flat plate shape, a honeycomb shape, a cylindrical shape, a ring shape, and a pellet shape.

  A method for applying the composition for gas combustion catalyst to the support is not particularly limited, and for example, a spin coating method, a spray method, a screen printing method, a stamp printing method, an ink jet method, or a dip method can be used.

  Hereinafter, the present invention will be described in detail with reference to examples. The following examples are examples of the present invention, and the present invention is not limited to the following examples.

<Example 1>
A solution was prepared by adding 22.6 g of basic aluminum acetate (Sigma Aldrich) and 1.2 g of acetic acid (Wako Pure Chemical Industries) to 560 g of water. This solution was put into an autoclave and hydrothermally treated at 200 ° C. for 24 hours. Thereafter, the autoclave was cooled to room temperature, and the reaction solution was taken out from the autoclave. A part of this reaction solution was dried to obtain a dried product. FIG. 1 is a photograph of this dried product observed with an FE-SEM (field emission scanning electron microscope). FIG. 2 shows the measurement results of this dried product by XRD (X-ray diffraction). From the results shown in FIGS. 1 and 2, it was confirmed that the dried product was an aggregate of boehmite nanorods.

Half of the above reaction solution was mixed with 2.58 g of an aqueous hexachloroplatinum (IV) acid solution (Tanaka Kikinzoku Kogyo Co., Ltd., Pt content: 15.325 wt%). Then, this liquid mixture was put in the environment of the temperature of 100 degreeC decompressed with the rotary evaporator, the solvent was removed from this liquid mixture, and solid substance was obtained. Next, the obtained solid was calcined in an air atmosphere at a temperature of 550 ° C. for 1 hour and then pulverized to obtain Catalyst A. The catalyst A supported by Pt was 10% by mass. FIG. 3 shows the measurement results of Catalyst A by XRD. As shown in FIG. 3, a diffraction peak of Pt and a diffraction peak of γ-alumina were observed. When the crystallite diameter of Pt was calculated from the diffraction peak of the Pt (111) plane near 2θ = 39.8 °, the crystallite diameter of Pt was 22.4 nm. Further, the BET specific surface area of the catalyst A was 99 m ² / g.

  0.50 g of catalyst A, 0.22 g of sol solution of boehmite particles (manufactured by Nissan Chemical Industries, Ltd., alumina content: 20% by weight, product name: alumina sol 520), and an appropriate amount of water are placed in a glass container, and rotation and revolution type stirring is performed. The composition for gas combustion catalyst according to Example 1 was obtained by stirring and degassing for several minutes using a machine (trade name: manufactured by Shinky Co., Ltd., trade name: Nertaro Awatori). FIG. 4 shows an XRD measurement result of a solid obtained by drying a small amount of alumina sol 520. From FIG. 4, it was confirmed that this solid was boehmite (AlO (OH)). The alumina sol 520 was confirmed to be a dispersion containing 23.5% by weight boehmite particles. The ratio of the boehmite mass to the catalyst mass (mass of boehmite / mass of catalyst) in the composition for gas combustion catalyst according to Example 1 was 0.10. The crystallite diameter of the boehmite particles calculated from the diffraction peak near 2θ = 13.9 ° in FIG. 4 was 8.3 nm.

<Example 2>
Instead of the hexachloroplatinum (IV) acid aqueous solution, the catalyst A was replaced in the same manner as in Example 1 except that 9.87 g of a PtPVP colloid aqueous solution (Tanaka Kikinzoku Kogyo Co., Ltd., Pt content: 4.0 wt%) was used. Catalyst B was prepared in the same manner as above, and a gas combustion catalyst composition according to Example 2 was obtained. The supporting rate of Pt in the catalyst B was 10% by mass. The XRD measurement result of the catalyst B is shown in FIG. Table 1 shows the measurement results of the BET specific surface area of catalyst B and the crystallite diameter of Pt in catalyst B. In the composition for gas combustion catalyst according to Example 2, the ratio of boehmite mass to catalyst mass (boehmite mass / catalyst mass) was 0.10.

<Example 3>
In the same manner as in Example 1 except that 4.46 g of an ethanolamine Pt solution (Tanaka Kikinzoku Kogyo Co., Ltd., Pt content: 8.850 wt%) was used instead of the hexachloroplatinic (IV) acid aqueous solution, Instead, catalyst C was prepared, and the composition for gas combustion catalyst according to Example 3 was obtained. The supporting rate of Pt in the catalyst C was 10% by mass. The XRD measurement result of the catalyst C is shown in FIG. Table 1 shows the measurement results of the BET specific surface area of catalyst C and the crystallite diameter of Pt in catalyst C. The ratio of the boehmite mass to the catalyst mass (boehmite mass / catalyst mass) was 0.10.

<Example 4>
Instead of the aqueous solution of hexachloroplatinic (IV) acid, in the same manner as in Example 1 except that 19.75 g of an aqueous PtPAA colloidal solution (Tanaka Kikinzoku Kogyo Co., Ltd., Pt content: 2.0 wt%) was used, A catalyst D was prepared to obtain a gas combustion catalyst composition according to Example 4. The loading ratio of Pt in catalyst D was 10% by mass. The XRD measurement result of catalyst D is shown in FIG. Table 1 shows the measurement results of the BET specific surface area of catalyst D and the crystallite diameter of Pt in catalyst D. The ratio of the boehmite mass to the catalyst mass (boehmite mass / catalyst mass) was 0.10.

<Example 5>
0.55 g of the catalyst B obtained in Example 2, 0.15 g of a sol solution of boehmite particles (manufactured by Nissan Chemical Industries, Ltd., alumina content: 20 wt%, product name: alumina sol 520), and 4.5 g of propylene glycol; 15 g of zirconia beads having a diameter of 1 mm were placed in a glass container and dispersed for 1 hour using a paint shaker. Thereafter, the zirconia beads were separated by filtration, and the composition for gas combustion catalyst according to Example 5 was obtained. In the composition for gas combustion catalyst according to Example 5, the ratio of boehmite mass to catalyst mass (boehmite mass / catalyst mass) was 0.07.

<Example 6>
0.50 g of catalyst B obtained in Example 2, 0.30 g of a sol solution of boehmite particles (manufactured by Nissan Chemical Industries, Ltd., alumina content: 10% by weight, product name: alumina sol 200), and 4.5 g of ethylene glycol; A zirconia bead having a diameter of 1 mm was placed in a glass container and subjected to a dispersion treatment for 1 hour using a paint shaker. Thereafter, the zirconia beads were separated by filtration, and the composition for gas combustion catalyst according to Example 6 was obtained. In the composition for gas combustion catalyst according to Example 6, the ratio of boehmite mass to catalyst mass (boehmite mass / catalyst mass) was 0.07.

  FIG. 8 shows an XRD measurement result of a solid obtained by drying a small amount of the alumina sol 200. As shown in FIG. 8, this solid was confirmed to be boehmite (AlO (OH)). The alumina sol 200 was confirmed to be a dispersion containing 11.8% by weight boehmite particles. The crystallite diameter of the boehmite particles calculated from the diffraction peak around 2θ = 38.5 ° in FIG. 8 was 3.6 nm.

<Comparative Example 1>
4.89 g of alumina (manufactured by Wako Pure Chemical Industries, Ltd.), 4.89 g of hexachloroplatinum (IV) acid aqueous solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., Pt content: 15.325 wt%), and 450 g of water are mixed in a beaker. did. Thereafter, this mixed solution was placed in an environment at a temperature of 100 ° C. reduced in pressure by a rotary evaporator, and the solvent was removed to obtain a solid. Next, the obtained solid was calcined in an air atmosphere at a temperature of 550 ° C. for 1 hour and then pulverized to obtain Catalyst E. The Pt loading on catalyst E was 10% by mass. The XRD measurement result of the catalyst E is shown in FIG. As shown in FIG. 9, a diffraction peak of Pt and a diffraction peak of alumina having an α-type crystal structure (α-alumina) were observed. When the crystallite diameter of Pt was calculated from the Pt (111) diffraction peak around 2θ = 39.8 °, the crystallite diameter of Pt was 36.5 nm. Further, the BET specific surface area of the catalyst E was 0.8 m ² / g.

  0.50 g of catalyst E, sol solution of boehmite particles (Nissan Chemical Industry Co., Ltd., alumina content: 20% by weight, trade name: alumina sol 520), 0.22 g, and an appropriate amount of water are placed in a glass container, and the rotation and revolution type Using a stirrer (manufactured by Shinky Co., Ltd., trade name: Nertaro Awatori), the mixture was stirred and degassed for several minutes to obtain a gas combustion catalyst composition according to Comparative Example 1. The ratio of the mass of boehmite particles to the mass of the catalyst in the gas combustion catalyst composition according to Comparative Example 1 (the mass of boehmite / the mass of the catalyst) was 0.10.

<Comparative example 2>
0.25 g of catalyst A, water-dispersed sol of silica having a particle size of 10 to 20 nm as a binder component (manufactured by Nissan Chemical Industries, SiO ₂ content: 20 wt%, trade name: Snowtex O) 0.11 g, and an appropriate amount of water Was put into a glass container and stirred and degassed for several minutes using a rotation and revolution type stirrer (trade name: Aritori Nertaro, manufactured by Shinky Corporation), to obtain a composition for gas combustion catalyst according to Comparative Example 2.

<Comparative Example 3 and Comparative Example 4>
A gas combustion catalyst composition according to Comparative Example 3 was obtained in the same manner as in Comparative Example 2 except that Catalyst B was used instead of Catalyst A. Moreover, the composition for gas combustion catalysts which concerns on the comparative example 4 was obtained like the comparative example 2 except having used the catalyst E instead of the catalyst A.

<Comparative Example 5>
0.25 g of catalyst A, 0.11 g of ethyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.) as a binder component, and an appropriate amount of terpineol were placed in a glass container, and a rotating and rotating stirrer (manufactured by Shinky Co., Ltd. Was used to stir and degas for several minutes to obtain a composition for gas combustion catalyst according to Comparative Example 5.

<Comparative Example 6 and Comparative Example 7>
A gas combustion catalyst composition according to Comparative Example 6 was obtained in the same manner as in Comparative Example 5 except that Catalyst B was used instead of Catalyst A. Moreover, the composition for gas combustion catalysts which concerns on the comparative example 7 was obtained like the comparative example 5 except having used the catalyst E instead of the catalyst A.

<Evaluation of adhesion of catalyst layer to support>
The composition for gas combustion catalyst according to each example and each comparative example was dropped onto a Si substrate with a thermal oxide film having an area of 2 cm × 2 cm, and applied to the substrate using a spin coater (manufactured by Mikasa). The substrate after coating was placed in a firing furnace and heated in an air atmosphere at a temperature of 500 ° C. for 10 minutes. This produced the board | substrate which hold | maintains a catalyst layer on one side. In any substrate formed using any composition for gas combustion catalyst, the thickness (film thickness) of the catalyst layer was 3 μm.

  In order to examine the adhesion between the catalyst layer obtained above and the Si substrate, the catalyst layer on the Si substrate was rubbed with a cellulose fiber nonwoven fabric (trade name: Bencot, manufactured by Asahi Kasei Co., Ltd.). At this time, the case where the catalyst layer was not peeled was evaluated as ◯, the case where a part of the catalyst layer was peeled as Δ, and the case where the catalyst layer was completely peeled as ×, and the adhesion between the catalyst layer and the Si substrate was evaluated in three stages. . Table 2 shows the evaluation results of the catalyst layers formed using the compositions for gas combustion catalysts according to each example and each comparative example. As shown in Table 2, the adhesion of the catalyst layers formed using the gas combustion catalyst compositions according to Examples 1 to 6 to the Si substrate was good.

<Evaluation of catalyst activity>
Using the composition for gas combustion catalyst according to Examples 1 to 4 and Comparative Example 1, a substrate holding a catalyst layer on one side was prepared in the same manner as the substrate used in the above adhesion evaluation. In any substrate, the thickness (film thickness) of the catalyst layer was 3 μm.

  In order to investigate the activity of the catalyst related to hydrogen combustion, the substrate holding the catalyst layer was placed in a quartz reaction tube having an inner diameter of 2.6 cm, and the quartz reaction tube was installed in a heating apparatus. While the air was allowed to flow through the reaction tube at a flow rate of 300 ml / min, the surface temperature of the catalyst layer was maintained at 50 ° C. (reference temperature). Subsequently, the gas to be circulated in the reaction tube was changed from air to a mixed gas of hydrogen and air containing 2% hydrogen on a volume basis, and this mixed gas was allowed to flow at a flow rate of 300 ml / min for 3 minutes. Thereafter, the gas flowing through the reaction tube was changed to air again, and air was flowed at a flow rate of 300 ml / min. During this period, the surface temperature of the catalyst layer increased due to the combustion heat of hydrogen and decreased after reaching the maximum temperature. The activity related to hydrogen combustion of each catalyst layer was evaluated by a temperature change ΔT (maximum temperature−reference temperature) from the reference temperature. The results are shown in Table 3. It can be determined that the greater the temperature change ΔT, the higher the activity of the catalyst for hydrogen combustion.

  As shown in Table 3, the catalyst layer formed using the composition for gas combustion catalyst according to Examples 1 to 4 showed high catalyst activity with respect to hydrogen combustion. It was also suggested that the activity of the catalyst layer related to hydrogen combustion increases as the BET specific surface area of the catalyst increases or as the Pt crystallite size in the catalyst decreases.

Claims (8)

A metal comprising an element belonging to Group 7 to Group 11 of the periodic table and / or an alloy containing the metal, and a support which is a metal oxide supporting the metal or the alloy, and has a BET specific surface area. A catalyst that is 30 m ² / g or more;
Boehmite particles,
It contains a polar solvent, and
The carrier is in the form of a rod having a minor axis length of 5-30 nm, a major axis length of 20-1000 nm, and an aspect ratio of 2-200,
The carrier comprises γ-alumina and no α-alumina,
Composition for gas combustion catalyst.   The composition for gas combustion catalysts according to claim 1, wherein the boehmite particles have a crystallite diameter of 20 nm or less. The composition for gas combustion catalyst according to claim 1 or 2, wherein the catalyst does not include a support that is a metal oxide supporting Co, Mn, Ni, Cu, and Fe. The elements, Ru, Rh, Ir, Pd , Pt, Ag, and Ru at least one element der selected from the group consisting of Au, gas combustion catalyst according to any one of 請 Motomeko 1-3 Composition.   The composition for gas combustion catalysts of any one of Claims 1-4 whose crystallite diameter of the said metal or the said alloy is 30 nm or less.   The composition for gas combustion catalyst according to any one of claims 1 to 5, wherein the catalyst exhibits a catalytic action with respect to hydrogen combustion. Applying the composition for gas combustion catalyst according to any one of claims 1 to 6 to a support;
Removing the polar solvent from the composition for gas combustion catalyst applied to the support to form a catalyst layer, and
A method for producing a support including a catalyst layer. A metal comprising an element belonging to Group 7 to Group 11 of the periodic table and / or an alloy containing the metal;
A support that is a metal oxide carrying the metal or the alloy,
Der BET specific surface area of 30m ² / g or more is,
The carrier is in the form of a rod having a minor axis length of 5-30 nm, a major axis length of 20-1000 nm, and an aspect ratio of 2-200,
The carrier comprises γ-alumina and no α-alumina,
Gas combustion catalyst.