Catalyst structure and method for producing catalyst structure

Abstract

To provide a catalyst structure enabling easy production and handling and having a large specific surface area, as well as a method for producing the same.SOLUTION: Provided is a catalyst structure used for a reforming reaction to modify a raw material, the catalyst structure comprising: a core layer; a first mask layer and a second mask layer disposed on both sides of the core layer; a substrate having a plurality of through-holes penetrating the respective layers; a coating containing a first metal element and covering the surface of the substrate including the inner walls of the through-holes; and a plurality of particulate bodies containing a second metal element and being in contact with the coating.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a catalyst structure and a method for manufacturing the catalyst structure.

Background Art

[0002] In a reforming reaction for reforming a raw material to obtain a reformed product, a catalyst for enhancing the reaction efficiency is used. The catalyst has a carrier and an active substance supported thereon. As a method for enhancing the reaction efficiency of the reforming reaction, there is a method of enhancing the contact efficiency between the raw material and the catalyst active sites by increasing the specific surface area of the catalyst. On the other hand, a catalyst having a large specific surface area often has an unstable shape and has a problem that it is difficult to handle.

[0003] For example, Patent Document 1 discloses a zeolite catalyst used for reforming a raw material. This zeolite catalyst contains a mixture of zeolite and a compound containing an alkaline earth metal and silicon. Such a zeolite catalyst is manufactured by kneading powdery zeolite and the compound, extrusion molding, and then firing. Thereby, a catalyst having a large specific surface area and an industrially easy-to-use shape can be obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The zeolite catalyst described in Patent Document 1 is manufactured through a process of molding and firing a mixture of powdery zeolite and a compound. Therefore, large-scale manufacturing equipment is required for manufacturing such a catalyst, and the manufacturing difficulty is high.

[0006] Therefore, it has been an issue to realize a catalyst structure that is easy to manufacture and handle and has a large specific surface area.

Means for Solving the Problem

[0007] The catalyst structure according to an application example of the present invention is a catalyst structure used in a reforming reaction for reforming a raw material, a substrate having a core layer, a first mask layer and a second mask layer provided on both surfaces of the core layer, and a plurality of through holes penetrating these layers, a film containing a first metal element and covering the surface of the substrate including the inner wall of the through hole, a plurality of granular bodies containing a second metal element and contacting the film, and is provided with.

[0008] The manufacturing method of the catalyst structure according to an application example of the present invention is a manufacturing method of a catalyst structure used in a reforming reaction for reforming a raw material, a preparation step of preparing a substrate having a core layer, and a first mask layer and a second mask layer provided on both surfaces of the core layer, a laser light irradiation step of forming a modified portion penetrating the substrate by performing a laser light irradiation treatment on the substrate, a through hole forming step of removing the modified portion by performing an etching treatment on the substrate and forming through holes in the substrate, a film forming step of forming a film containing a first metal element on the surface of the substrate and the inner wall of the through hole, a granular body forming step of forming a plurality of granular bodies containing a second metal element on the film, and has.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 9

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the catalyst structure and the method for manufacturing the catalyst structure of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0011] 1. Catalyst Structure First, the catalyst structure according to the embodiment will be described.

[0012] FIG. 1 is a partial cross-sectional view showing the catalyst structure 1 according to the embodiment. In FIG. 1, the X-axis, Y-axis, and Z-axis are set as three axes orthogonal to each other. Each axis is represented by an arrow, and the tip side of the arrow is defined as "plus" and the base end side of the arrow is defined as "minus". In the following description, for example, the "X-axis direction" includes both the plus direction and the minus direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Further, in the following description, in particular, the Z-axis plus side is also referred to as "up", and the Z-axis minus side is also referred to as "down".

[0013] The catalyst structure 1 shown in Fig. 1 is used as a catalyst in a reforming reaction for reforming a raw material. Examples of the raw material include, but are not limited to, carbon oxides such as carbon monoxide and carbon dioxide, and hydrocarbons such as methane and propane. When these raw materials are brought into contact with the catalyst structure 1, the raw materials are reformed to obtain products. Examples of the products include, but are not limited to, hydrogen, hydrocarbons such as methane and propane, and alcohols such as methanol and ethanol.

[0014] In the following description, for the sake of convenience of explanation, the case where carbon dioxide and hydrogen are used as raw materials and the product is methanol will be described as an example.

[0015] The catalyst structure 1 shown in Fig. 1 includes a substrate 2, a coating 3, and a plurality of granular bodies 4. The substrate 2 has a plate shape extending along the X-Y plane. As shown in Fig. 1, the substrate 2 has a core layer 22, a first mask layer 24, a second mask layer 26, and a plurality of through holes 28 penetrating through these layers.

[0016] The coating 3 contains a first metal element and covers the surface of the substrate 2 including the inner walls of the through holes 28. The granular body 4 contains a second metal element and is in contact with the coating 3.

[0017] One of the coating 3 and the granular body 4 is a catalyst component and the other is a carrier. As an example, when the coating 3 is made of metallic Cu and the granular body 4 is made of zirconium oxide, the coating 3 is the catalyst component and the granular body 4 serves as the carrier. By contacting each other, catalytic active sites C are formed at the interface between the coating 3 and the granular body 4. By forming more of these catalytic active sites C per unit area of the catalyst structure 1, the efficiency of the reforming reaction of the raw material by the catalyst structure 1 can be increased. As a result, the raw material can be efficiently reformed into the product.

[0018] Since the substrate 2 has a plurality of through-holes 28, it has a large specific surface area. Therefore, a catalyst structure 1 with a high density of catalytic active sites C can be realized. In addition, since the substrate 2 has a plate shape, existing precision processing technologies can be used, and a catalyst structure 1 that is easy to manufacture can be realized. Furthermore, since such a catalyst structure 1 has a plate shape, it is easy to handle and, for example, can be stacked, enabling high-density mounting. That is, by stacking a plurality of catalyst structures 1 with a predetermined gap and storing them in a container, a reforming device with a high density of catalytic active sites C can be constructed. Such a reforming device can efficiently reform a large amount of raw materials even in a space-saving manner, and thus can efficiently manufacture a large amount of products such as methanol at low cost. In particular, when carbon dioxide is used as a raw material, it can contribute to the realization of carbon neutrality or carbon negativity.

[0019] 1.1. Substrate As described above, the substrate 2 has a core layer 22, a first mask layer 24, a second mask layer 26, and a plurality of through-holes 28 that penetrate each of these layers.

[0020] Examples of the constituent material of the core layer 22 include silicon materials such as silicon and silicon carbide, metal materials such as aluminum and iron, glass materials, ceramic materials, and organic materials such as various resins. Further, a composite material combining two or more of these may also be used.

[0021] Among these, the core layer 22 preferably contains silicon. The core layer 22 containing silicon is distributed as a silicon wafer, has stable quality, and is easily available. In addition, for materials containing silicon, since precision processing technology by etching methods has been established, it is suitable as the constituent material of the core layer 22.

[0022] Also, the silicon may be amorphous silicon or polycrystalline silicon, but single-crystalline silicon is preferred. Thereby, the core layer 22 can be machined more precisely by using an anisotropic etching method. As a result, the core layer 22 with a particularly increased specific surface area can be obtained.

[0023] Furthermore, when the core layer 22 is composed of single-crystalline silicon, the main plane of the core layer 22 is preferably a (110) plane or a (100) plane. Since the etching rate of these crystal planes is faster than that of the (111) plane, precision machining by anisotropic etching becomes possible.

[0024] The thickness of the core layer 22 in the Z-axis direction is not particularly limited, but is preferably 100 μm or more and 2000 μm or less, more preferably 200 μm or more and 1000 μm or less, and even more preferably 300 μm or more and 600 μm or less. Thereby, while ensuring the rigidity of the catalyst structure 1, weight reduction and thinning can be achieved. As a result, the catalyst structure 1 that is particularly easy to manufacture and handle can be realized.

[0025] The size of the substrate 2 in the X-Y plane is not particularly limited, but as an example, it is preferably 20 mm or more and 1000 mm or less, more preferably 50 mm or more and 500 mm or less. Thereby, a substrate 2 that is easy to manufacture and handle and has a sufficiently large specific surface area can be obtained. As a result, the catalyst structure 1 that can hold more of the coating 3 and the granular body 4 per unit area can be realized. Note that the above size is the maximum length that can be taken in the X-Y plane.

[0026] The first mask layer 24 and the second mask layer 26 are provided on two main planes (upper surface and lower surface) of the core layer 22 that are in a front-back relationship with each other. The first mask layer 24 is provided on the upper surface of the core layer 22, and the second mask layer 26 is provided on the lower surface of the core layer 22.

[0027] As the constituent materials of each of the first mask layer 24 and the second mask layer 26, a material that functions as an intermediate layer for enhancing the adhesion between the core layer 22 and the coating 3 and preferably can function as an etch stopper when the core layer 22 is processed by an etching method is used. Examples of materials having such functions include silicon compounds such as silicon oxide, silicon nitride, silicon oxynitride, and silicon carbide, various metal materials, various organic materials, and the like. Among these, silicon oxide is preferably used.

[0028] The average thickness of each of the first mask layer 24 and the second mask layer 26 is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less, and more preferably 2 μm or more and 5 μm or less. By setting the thickness of the mask layer within the above range, the adhesion between the core layer 22 and the coating 3 can be sufficiently enhanced. Further, by setting the thickness of each mask layer within the above range, when the core layer 22 is processed by an etching method, these mask layers can function as good etch stoppers.

[0029] Note that the average thickness of each mask layer is the average value of the thicknesses measured at 10 or more randomly extracted points in the magnified observation image of the cross section of each mask layer.

[0030] The through holes 28 penetrate the core layer 22, the first mask layer 24, and the second mask layer 26. A plurality of through holes 28 are distributed at intervals from each other. By providing the through holes 28, the specific surface area of the substrate 2 can be enlarged. As a result, the area of the inner wall of the through holes 28 can be added to the area of the surface of the substrate 2, so that a wider area for the provided coating 3 can be secured. As a result, the density of the catalytic active sites C can be increased.

[0031] The arrangement pattern of the through holes 28 is not particularly limited and may be equally spaced or random. However, from the viewpoint of easily increasing the arrangement density of the through holes 28, it is preferable that they are arranged at equal intervals.

[0032] The average inner diameter of the through-hole 28 is not particularly limited, but is preferably 1 μm or more and 300 μm or less, more preferably 10 μm or more and 200 μm or less, and even more preferably 50 μm or more and 100 μm or less. If the average inner diameter of the through-hole 28 is within the above range, the number density of the through-holes 28 can be sufficiently ensured, and the specific surface area of the catalyst structure 1 can be sufficiently widened. Further, the film 3 and the granular material 4 can be efficiently formed on the inner wall of the through-hole 28, and even after the film 3 and the granular material 4 are formed, it becomes possible to circulate the raw material through the through-hole 28.

[0033] In addition, if the average inner diameter of the through-hole 28 is less than the lower limit value, it may be difficult to form the film 3 on the inner wall of the through-hole 28, or it may be difficult to circulate the gas containing the raw material through the through-hole 28. On the other hand, if the average inner diameter of the through-hole 28 exceeds the upper limit value, the number density of the through-holes 28 decreases, so that the efficiency of the reforming reaction of the raw material by the catalyst structure 1 may decrease.

[0034] The average inner diameter of the through-hole 28 is the average value of the inner diameters (equivalent circle diameters) measured by randomly extracting 10 or more images after identifying the image of the through-hole 28 in the enlarged observation image of the surface of the substrate 2.

[0035] The number density of the through-holes 28 on the surface of the substrate 2 is not particularly limited, but is preferably 0.1 holes / mm 2 or more and 10,000 holes / mm 2 or less, more preferably 3 holes / mm 2 or more and 10,000 holes / mm 2 or less, and even more preferably 30 holes / mm 2 or more and 10,000 holes / mm 2 or less. If the number density of the through-holes 28 is within the above range, the number density of the through-holes 28 is optimized, so that it is possible to increase the density of the number of catalytic active points C while avoiding a decrease in the mechanical strength of the substrate 2.

[0036] Note that if the number density of the through-holes 28 is lower than the lower limit value, the number density of the catalytic active sites C may be insufficient, and the efficiency of the reforming reaction of the raw material by the catalyst structure 1 may decrease. On the other hand, if the number density of the through-holes 28 exceeds the upper limit value, the mechanical strength of the substrate 2 may decrease.

[0037] Note that the number density of the through-holes 28 is measured as follows. First, in the magnified observation image of the surface of the substrate 2, the image of the through-holes 28 is identified. Next, the number of images in one image is counted. Then, the number of images is divided by the area (mm 2 ) of one image to obtain the number density (pieces / mm 2 ).

[0038] 1.2. Coating The coating 3 covers the surface (upper and lower surfaces) of the substrate 2 and the inner walls of the through-holes 28, respectively.

[0039] The coating 3 contains a first metal element and functions as a catalyst component, for example. Examples of the first metal element include Cu, Pt, In, Zn, Ru, Sn, Au, Re, etc. Among these, the first metal element is preferably Cu, Pt, or In. By contacting these elements with the second metal element, a particularly high catalytic activity is exhibited at the catalytic active site C. When carbon dioxide and hydrogen are brought into contact with this catalytic active site C under various conditions (temperature, pressure, supply rate of raw material, reaction time, etc.) being adjusted, the probability of carbon dioxide being hydrogenated increases, and the efficiency of various reforming reactions such as methanol production can be enhanced.

[0040] The content of the first metal element in the coating 3 is not particularly limited, but is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more.

[0041] The film 3 may contain elements other than the first metal element, if necessary. That is, the first metal element may exist alone or as a compound or mixture with other elements. Specific examples of the single substance include metallic copper, metallic platinum, and the like. Examples of the compound include, for example, oxides of the first metal element, and specific examples include indium oxide and the like. Examples of the mixture include, for example, alloys containing the first metal element.

[0042] As shown in FIG. 1, the film 3 preferably continuously covers the surface of the substrate 2 and the inner wall of the through hole 28, but may be partially interrupted. The ratio (coverage rate) of the coverage area of the film 3 to the total area of the surface of the substrate 2 and the inner wall of the through hole 28 is preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more. Thereby, the density of the catalytic active sites C in the catalyst structure 1 can be sufficiently increased.

[0043] The average thickness of the film 3 is not particularly limited, but is preferably 1 nm or more and 100 nm or less, and more preferably 1 nm or more and 50 nm or less. If the average thickness of the film 3 is within the above range, the adhesion of the film 3 can be ensured, so that the possibility of realizing the catalyst structure 1 with excellent long-term reliability is increased. In addition, the possibility of realizing the catalyst structure 1 with a sufficiently high density of the catalytic active sites C is increased.

[0044] Note that if the average thickness of the film 3 is less than the lower limit value, the adhesion of the film 3 may decrease or the density of the catalytic active sites C may become insufficient. On the other hand, if the average thickness of the film 3 exceeds the upper limit value, the effect of increasing the adhesion of the film 3 and the density of the catalytic active sites C reaches a plateau, and there is a possibility that the film 3 is easily peeled off.

[0045] The average thickness of the film 3 is the average value of the thicknesses measured at 10 or more randomly extracted points in the magnified observation image of the cross section of the film 3.

[0046] 1.3. Granular bodies The granular bodies 4 are in contact with the coating 3 at a plurality of points. The granular bodies 4 are granular in shape. As a result, the contact efficiency between the catalytic active sites C formed at the interface between the granular bodies 4 and the coating 3 and the raw material can be increased as compared with the case where the granular bodies 4 are present in a layered form rather than in a granular form. As a result, even if the catalytic active sites C are present at a high density, a catalyst structure 1 having a high reforming reaction efficiency can be realized.

[0047] Note that the shape of the granular bodies 4 when the catalyst structure 1 is viewed in plan from the Z-axis direction is not particularly limited as long as it is granular, and may be, for example, a specific shape such as a circle or a polygon, or an irregular shape that is not a specific shape. Also, the shapes of the granular bodies 4 may be the same as each other or different from each other.

[0048] The granular bodies 4 contain a second metal element and function, for example, as a carrier on which a catalyst is supported. Examples of the second metal element include Zr, Hf, Ta, Zn, Mo, Ti, Ga, Al, Sn, etc. Among these, the second metal element is preferably Zr, Hf, Ta, Zn, Mo or Ti. By contacting these elements with the first metal element, a particularly high catalytic activity is exhibited at the catalytic active sites C. When carbon dioxide and hydrogen are brought into contact with the catalytic active sites C under various conditions (temperature, pressure, supply rate of raw material, reaction time, etc.) adjusted, the probability of carbon dioxide being hydrogenated increases, and the efficiency of various reforming reactions such as the production of methanol can be increased.

[0049] The granular bodies 4 may contain elements other than the second metal element, if necessary. That is, the second metal element may exist alone or as a compound or mixture with other elements. Examples of the compound include oxides of the second metal element, and specific examples include zirconium oxide, hafnium oxide, tantalum oxide, zinc oxide, molybdenum oxide, titanium oxide, etc.

[0050] Further, examples of the preferred combination of the first metal element and the second metal element include the following combinations. · When the first metal element is Cu, the second metal element is Zr, Hf, Ta or Zn · When the first metal element is Pt, the second metal element is Mo or Ti · When the first metal element is In, the second metal element is Zr According to such a combination, the catalytic activity of the catalytic active site C can be particularly enhanced.

[0051] The granular bodies 4 may be in contact with each other, but preferably they are separated from each other as shown in FIG. 1. Thereby, compared with the case where the granular bodies 4 are in contact with each other, the contact efficiency between the catalytic active site C formed at the interface between the granular body 4 and the film 3 and the raw material can be enhanced.

[0052] The average particle diameter of the granular body 4 is not particularly limited because it varies depending on other conditions. As an example, it is preferably 1 nm or more and 100 nm or less, more preferably 2 nm or more and 50 nm or less, and even more preferably 3 nm or more and 20 nm or less. If the average particle diameter of the granular body 4 is within the above range, sufficient adhesion between the granular body 4 and the film 3 can be ensured, and the number density of the catalytic active sites C can be enhanced. Thereby, the efficiency of the reforming reaction in the catalyst structure 1 can be particularly enhanced.

[0053] In addition, when the average particle diameter of the granular body 4 is less than the lower limit value, the manufacturing difficulty of the granular body 4 may increase. On the other hand, when the average particle diameter of the granular body 4 exceeds the upper limit value, the granular body 4 may easily fall off, or the number density of the catalytic active sites C may decrease and the efficiency of the reforming reaction may decrease.

[0054] The average particle diameter of the granular body 4 is the average value of the particle diameters (equivalent circle diameters) measured by randomly extracting 10 or more particle images after identifying the particle images of the granular body 4 based on the difference in contrast or the like in the enlarged observation image of the surface of the catalyst structure 1.

[0055] 2. Method for manufacturing the catalyst structure Next, a method for manufacturing the catalyst structure according to the embodiment will be described. Here, a method for manufacturing the catalyst structure 1 shown in FIG. 1 will be described as an example.

[0056] FIG. 2 is a process diagram for explaining a method for manufacturing the catalyst structure 1 shown in FIG. 1. FIGS. 3 to 9 are cross-sectional views for explaining the method for manufacturing the catalyst structure 1 shown in FIG. 2.

[0057] The method for manufacturing the catalyst structure 1 shown in FIG. 2 is a method for manufacturing the catalyst structure 1 used in the reforming reaction for reforming raw materials, and includes a preparation step S102, a half-etching step S104, a laser light irradiation step S106, a through-hole forming step S108, a film forming step S110, a granular body forming step S112, and a reduction treatment step S114.

[0058] 2.1. Preparation Step In the preparation step S102, a substrate 20 is prepared. As shown in FIG. 3, the substrate 20 has a core layer 22 and a first mask layer 24 and a second mask layer 26 provided on both surfaces (upper surface and lower surface) of the core layer 22.

[0059] The first mask layer 24 may be provided with openings 25 in advance. The opening 25 is a hole penetrating the first mask layer 24 and is provided at a position where a through-hole 28 is to be formed in the through-hole forming step S108 described later. Therefore, the first mask layer 24 shown in FIG. 3 has a plurality of openings 25 that expose the core layer 22. Similarly, the second mask layer 26 may be provided with openings 27 in advance. The opening 27 is a hole penetrating the second mask layer 26 and is provided at a position where a through-hole 28 is to be formed in the through-hole forming step S108 described later. Therefore, the second mask layer 26 shown in FIG. 3 has a plurality of openings 27 that expose the core layer 22. Thereby, in the through-hole forming step S108 described later, a plurality of through-holes 28 can be formed simultaneously and easily according to the positions of the openings 25 and 27.

[0060] As a method for forming the first mask layer 24 and the second mask layer 26 on the core layer 22, for example, there is a method of forming a constituent material through a mask material (not shown) having a mask pattern corresponding to each shape of the first mask layer 24 and the second mask layer 26 to be formed. According to such a method, since the constituent material is formed in a region corresponding to the mask pattern of the mask material, the first mask layer 24 and the second mask layer 26 can be efficiently formed.

[0061] Note that the method for forming the first mask layer 24 and the second mask layer 26 is not limited to this. For example, after forming a film of a material or modifying the surface of the core layer 22 to form a film on the entire both surfaces of the core layer 22, the first mask layer 24 and the second mask layer 26 may be formed by removing a part of the film. Examples of the removing method include a method combining a photolithography method and an etching method, a machining method, and the like.

[0062] As a method for forming a film of each constituent material of the first mask layer 24 and the second mask layer 26, for example, there are a vapor deposition method such as a thermal CVD method and a plasma CVD method, and a thermal oxidation method.

[0063] In the vapor deposition method, the film may be formed under normal pressure, but preferably under reduced pressure. Thereby, denser first mask layer 24 and second mask layer 26 can be obtained.

[0064] 2.2. Half-etching process The half-etching process S104 is provided between the preparation process S102 and the laser light irradiation process S106 described later. Note that the half-etching process S104 is provided as necessary and may be omitted.

[0065] In the half-etching step S104, a half-etching process E1 shown in FIG. 3 is performed on the substrate 20. The half-etching process E1 is a process of etching to such an extent that the core layer 22 is not penetrated, using the first mask layer 24 and the second mask layer 26 as etching masks, respectively. As a result, the surface of the core layer 22 corresponding to the openings 25 and 27 is selectively recessed, and a recess 29 shown in FIG. 4 is formed. By forming such a recess 29, when the core layer 22 is altered in the laser light irradiation step S106 described later, the thickness of the core layer 22 can be reduced in advance. As a result, since the irradiation amount of the laser light can be reduced, the time required for the laser light irradiation step S106 can be shortened.

[0066] The half-etching process E1 may be a dry etching process, but is preferably a wet etching process. Thereby, the recess 29 can be formed efficiently. Examples of the etching solution used in the wet etching process include an acid-based etching solution containing hydrofluoric acid and nitric acid, and an alkali-based etching solution such as an aqueous solution of potassium hydroxide or tetraammonium hydroxide. Among these, an alkali-based etching solution is preferably used.

[0067] When the constituent material of the core layer 22 is a single crystal material, the etching rate varies depending on the crystal plane, and thus the recess 29 can be formed efficiently using this property. For example, when the constituent material of the core layer 22 is single crystal silicon and the main surface of the core layer 22 is the (110) plane, the etching rate decreases when the (111) plane is exposed after the start of the wet etching process. Therefore, the recess 29 having a predetermined depth can be formed efficiently without strictly controlling the depth of the recess 29.

[0068] The time of the half-etching process E1 is appropriately adjusted according to the etching rate and the like. As an example, it is set to be 5 minutes or more and 60 minutes or less. Also, the temperature of the etching solution is appropriately set according to the etching rate and the like. As an example, it is set to be 40°C or more and 90°C or less.

[0069] The depth of the recess 29 is not particularly limited, but is preferably 3 μm or more and 400 μm or less, more preferably 5 μm or more and 50 μm or less. By providing the recess 29 with such a depth, the positional accuracy of the altered portion 31 formed in the laser light irradiation step S106 described later can be increased, or the formation efficiency of the altered portion 31 can be increased.

[0070] 2.3. Laser light irradiation step In the laser light irradiation step S106, the laser light irradiation process L shown in FIG. 4 is performed on the substrate 20 that has undergone the half-etching step S104. As a result, the region penetrating the substrate 20 is altered, and the altered portion 31 shown in FIG. 5 is formed. The altered portion 31 is formed by altering the core layer 22 by the laser light irradiation process L. Alteration means changing the crystal structure, composition, etc. from the original state. For example, when the constituent material of the core layer 22 is single-crystalline silicon, it changes to amorphous silicon by the laser light irradiation process L.

[0071] Examples of the laser used for the laser light irradiation process L include a YAG laser, a YVO 4 laser, a YLF laser, and the like.

[0072] In addition, in the laser light irradiation process L, it may be performed through an optical system that focuses the laser light on the focal point. In this case, it is preferable to align the focal point within the core layer 22. Moreover, the focal point may be moved in the thickness direction of the core layer 22.

[0073] 2.4. Through-hole formation step In the through-hole forming step S108, the etching process E2 shown in FIG. 5 is performed on the substrate 20 that has undergone the laser beam irradiation step S106. As a result, the altered portion 31 is removed, and a through-hole 28 is obtained as shown in FIG. 6. The etching rate of the altered portion 31 is higher than that of the unaltered portion, that is, the portion of the core layer 22 covered by the first mask layer 24 and the second mask layer 26. Therefore, the altered portion 31 can be selectively removed by the etching process E2. As a result, the through-hole 28 is formed corresponding to the openings 25 and 27, and the substrate 2 shown in FIG. 1 is obtained.

[0074] The etching process E2 may be a dry etching process, but is preferably a wet etching process. Thereby, the through-hole 28 can be efficiently formed. Examples of the etching solution used in the wet etching process include an acid-based etching solution containing hydrofluoric acid and nitric acid, and an alkaline-based etching solution such as an aqueous solution of potassium hydroxide or tetraammonium hydroxide. Among these, an alkaline-based etching solution is preferably used.

[0075] The time of the etching process E2 is appropriately adjusted according to the etching rate. As an example, it is set to be 30 minutes or more and 240 minutes or less. The temperature of the etching solution is appropriately set according to the etching rate and the like. As an example, it is set to be 40°C or more and 90°C or less.

[0076] 2.5. Film formation step In the film formation step S110, as shown in FIG. 7, a film 3 is formed on the surface of the substrate 2 and the inner wall of the through-hole 28.

[0077] Examples of the film formation method of the film 3 include vapor deposition methods such as thermal CVD method, plasma CVD method, and MOCVD method.

[0078] In the vapor deposition method, the film may be formed under normal pressure, but preferably under reduced pressure. Thereby, the film 3 is easily formed on the inner wall of the through-hole 28, and the coverage rate of the film 3 can be increased. As a result, further densification of the catalytic active sites C can be achieved.

[0079] When forming the coating film 3, the temperature is appropriately set according to the constituent material of the coating film 3, the film forming method, etc., and is not particularly limited, but is preferably 100°C or higher and 500°C or lower, more preferably 150°C or higher and 300°C or lower. Thereby, since the coating film 3 can be formed at a relatively low temperature and in a short time, the coating film 3 can be efficiently formed.

[0080] The pressure when forming the coating film 3 is preferably 100 Pa or lower, more preferably 0.001 Pa or higher and 10 Pa or lower, and still more preferably 0.001 Pa or higher and 1 Pa or lower. Thereby, the coverage rate and the denseness of the coating film 3 can be particularly enhanced. As a result, the catalytic active sites C can be particularly densified.

[0081] The raw material when forming the coating film 3 is appropriately selected according to the constituent material of the coating film 3. For example, when the first metal element contained in the coating film 3 is Cu, an organometallic compound containing Cu is used. Specifically, in addition to copper trimethylvinylsilyl hexafluoroacetylacetonate {Cu(I)(hfac)(tmvs) complex}, Cu(II)(hfac) 2 complex, Cu(II)(6MHPD) 2 complex, Cu(II)(2MHXD) 2 complex, Cu(II)(TMOD) 2 complexes and other organometallic complexes can be mentioned. By using such an organometallic complex as the raw material, Cu can be formed even at a relatively low temperature.

[0082] 2.6. Granular body forming step In the granular body forming step S112, as shown in FIG. 8, a plurality of granular bodies 4 are formed on the coating film 3.

[0083] Examples of the method for forming the granular bodies 4 include, for example, vacuum evaporation method, sputtering method, CVD method, atomic layer deposition method (ALD), etc. Among these, the atomic layer deposition method is preferably used. By performing the process of forming the granular bodies 4 by the atomic layer deposition method, minute granular bodies 4 can be efficiently formed without performing patterning or the like. Specifically, in the atomic layer deposition method, island-shaped nuclei are first formed on the film 3, and then the nuclei grow to form the granular bodies 4. Therefore, by adjusting the film formation time according to the growth stage of the nuclei, granular granular bodies 4 can be efficiently formed. Also, in the atomic layer deposition method, since the film formation amount can be controlled at the atomic layer level, the particle size of the granular bodies 4 can be precisely controlled. Furthermore, in the atomic layer deposition method, since the raw material gas and the oxidizing agent can penetrate into the concave portions and holes to form a film, the granular bodies 4 can also be efficiently formed on the inner walls of the through holes 28. Therefore, according to the atomic layer deposition method, the catalyst structure 1 in which the catalytic active points C are formed particularly densely can be manufactured.

[0084] The raw material gas and the oxidizing agent used in the atomic layer deposition method are appropriately selected according to the constituent material of the granular bodies 4. For example, the raw material gas is a gas containing a precursor of the constituent material. For example, when the second metal element contained in the granular bodies 4 is Zr, zirconium oxide (ZrO 2 ) can be used. In this case, examples of the precursor include, for example, Zr(O t Bu) 4 (zirconium tert-butoxide, ZTB), Zr(NEt 2 ) 4 (tetrakis(diethylamide)zirconium, TDEAZ), Zr(NMeEt) 4 (tetrakis(ethylmethylamide)zirconium, TEMAZ), Zr(NMe 2 ) 4 (tetrakis(dimethylamide)zirconium, TDMAZ), etc.

[0085] Hereinafter, an example of the procedure for forming the granular material 4 by atomic layer deposition will be described. First, the substrate 2 with the film 3 formed thereon is placed in a chamber capable of evacuation and atmosphere control. Next, a raw material gas containing a precursor is introduced into the chamber and adsorbed on the film 3. Next, after discharging the excess precursor, an oxidizing agent is introduced into the chamber. Examples of the oxidizing agent include ozone, plasma oxygen, water vapor, etc. The introduced oxidizing agent reacts with the precursor adsorbed on the film 3, and the granular material 4 is formed.

[0086] When forming the granular material 4, the temperature in the chamber is appropriately set according to the types of the precursor and the oxidizing agent, etc., but it is preferably 100°C or higher and 350°C or lower, and more preferably 200°C or higher and 300°C or lower. Thereby, while suppressing the deterioration of the film 3 and the substrate 2 due to heat, the precursor can be reacted with high precision. As a result, the granular material 4 with a sufficiently high content of the target constituent material and capable of a highly efficient modification reaction can be formed.

[0087] When forming the granular material 4, the pressure in the chamber is preferably 100 Pa or lower, more preferably 0.001 Pa or higher and 10 Pa or lower, and even more preferably 0.001 Pa or higher and 1 Pa or lower. Thereby, since the concentrations of the precursor and the oxidizing agent can be optimized, the reaction efficiency of the precursor can be increased. As a result, the granular material 4 with a sufficiently high content of the target constituent material and capable of a highly efficient modification reaction can be formed.

[0088] When the granular material 4 is formed as described above, catalytic active sites C shown in FIG. 9 are formed at the interface between the granular material 4 and the film 3. Thereby, the catalyst structure 1 shown in FIG. 9 is obtained.

[0089] 2.7. Reduction treatment step In the reduction treatment step S114, the catalyst structure 1 that has undergone the granule formation step S112 is subjected to a reduction treatment. As a result, the oxide is reduced in at least one of the coating 3 and the granules 4. Specifically, when the constituent material of the coating 3 is a metal such as Cu, the copper oxide contained in the coating 3 is reduced to metallic Cu. On the other hand, unlike this embodiment, when the constituent material of the granules 4 is a metal such as Cu, the copper oxide contained in the granules 4 is reduced to metallic Cu. As a result, the catalytic activity at the catalytic active site C is enhanced. Note that the reduction treatment step S114 is provided as necessary and may be omitted.

[0090] Examples of the reducing agent used for the reduction treatment include hydrogen, carbon monoxide, methane, and the like. Alternatively, the catalyst structure 1 may be heated under reduced pressure, and the oxide may be reduced by thermal dissociation. Among these, considering the stability, efficiency, safety, etc. of the reduction reaction, the reduction treatment using hydrogen is preferably used. By performing the reduction treatment, the catalytic activity of the catalytic active site C is enhanced. Thereby, the catalyst structure 1 with improved reforming efficiency can be obtained.

[0091] In the case of the reduction treatment using a reducing agent, the catalyst structure 1 is heated while introducing the reducing agent into the heating furnace.

[0092] The temperature in the heating furnace in the reduction treatment is not particularly limited, but is preferably 100°C or higher and 700°C or lower, and more preferably 200°C or higher and 500°C or lower. The heating time is not particularly limited, but is preferably 0.5 hours or longer and 10 hours or shorter, and more preferably 1 hour or longer and 5 hours or shorter. Thereby, the catalytic activity can be enhanced efficiently.

[0093] The introduction amount of the reducing agent into the heating furnace in the reduction treatment is not particularly limited, but is preferably 50 mL / min or more and 1000 mL / min or less, and more preferably 100 mL / min or more and 500 mL / min or less. By adjusting to such an optimum value, it becomes easier to efficiently enhance the catalytic activity.

[0094] 3. Effects Exhibited by the Embodiment As described above, the catalyst structure 1 according to the above embodiment is a catalyst structure used for a reforming reaction to reform a raw material, and includes a substrate 2, a film 3, and a plurality of granular bodies 4. The substrate 2 has a core layer 22, a first mask layer 24 and a second mask layer 26 provided on both surfaces of the core layer 22, and a plurality of through holes 28 penetrating through these layers. The film 3 contains a first metal element and covers the surface of the substrate 2 including the inner walls of the through holes 28. The granular bodies 4 contain a second metal element and are in contact with the film 3.

[0095] According to such a configuration, a catalyst structure 1 that is easy to manufacture and handle and has a large specific surface area can be obtained. Such a catalyst structure 1 can be used, for example, to construct a reforming apparatus in which catalytic active sites C are densely integrated by stacking (laminating) a plurality of them with a predetermined gap and storing them in a container. Such a reforming apparatus can efficiently reform a large amount of raw material even in a space-saving manner.

[0096] Further, the core layer 22 may contain silicon. In this case, the first mask layer 24 and the second mask layer 26 preferably contain silicon oxide.

[0097] According to such a configuration, for example, when processing the core layer 22 by an etching method, the first mask layer 24 and the second mask layer 26 can function as an etch stopper. Thereby, precise processing of the core layer 22 by the etching method becomes possible.

[0098] Further, the average inner diameter of the through holes 28 is preferably 1 μm or more and 300 μm or less. According to such a configuration, the number density of the through holes 28 can be sufficiently ensured, and the specific surface area of the catalyst structure 1 can be sufficiently widened. Also, the film 3 and the granular bodies 4 can be efficiently formed on the inner walls of the through holes 28, and even after forming the film 3 and the granular bodies 4, it becomes possible to circulate the raw material through the through holes 28.

[0099] Further, the average thickness of each of the first mask layer 24 and the second mask layer 26 is preferably 0.5 μm or more and 10 μm or less.

[0100] According to such a configuration, a first mask layer 24 and a second mask layer 26 that can sufficiently enhance the adhesion between the core layer 22 and the coating 3 can be obtained. Further, for example, when the core layer 22 is processed by an etching method, a first mask layer 24 and a second mask layer 26 that function as good etch stoppers can be obtained.

[0101] Further, the average thickness of the coating 3 is preferably 1 nm or more and 100 nm or less. According to such a configuration, since the adhesion of the coating 3 can be ensured, the catalyst structure 1 excellent in long-term reliability can be realized. Further, the catalyst structure 1 having a sufficiently high density of catalytic active sites C can be realized.

[0102] Further, the average particle diameter of the granular material 4 is preferably 1 nm or more and 100 nm or less. According to such a configuration, the adhesion between the granular material 4 and the coating 3 can be sufficiently ensured, and the number density of the catalytic active sites C can be increased. Thereby, the efficiency of the reforming reaction in the catalyst structure 1 can be particularly increased.

[0103] Further, when the first metal element is Cu, Pt, or In, the second metal element is preferably Zr, Hf, Ta, Zn, Mo, or Ti. According to such a configuration, the catalytic activity of the catalytic active site C can be particularly increased.

[0104] The method for manufacturing the catalyst structure according to the above embodiment is a method for manufacturing the catalyst structure 1 used in the reforming reaction for reforming raw materials, and includes a preparation step S102, a laser light irradiation step S106, a through-hole formation step S108, a film formation step S110, and a granule formation step S112. In the preparation step S102, a substrate 2 having a core layer 22 and a first mask layer 24 and a second mask layer 26 provided on both surfaces of the core layer 22 is prepared. In the laser light irradiation step S106, by performing a laser light irradiation treatment L on the substrate 2, a modified portion 31 penetrating the substrate 2 is formed. In the through-hole formation step S108, by performing an etching treatment E2 on the substrate 2, the modified portion 31 is removed, and a through-hole 28 is formed in the substrate 2. In the film formation step S110, a film 3 containing a first metal element is formed on the surface of the substrate 2 and the inner wall of the through-hole 28. In the granule formation step S112, a plurality of granules 4 containing a second metal element are formed on the film 3.

[0105] According to such a configuration, the catalyst structure 1 that is easy to handle and has a large specific surface area can be easily manufactured.

[0106] Further, the core layer 22 may contain silicon. In this case, the first mask layer 24 and the second mask layer 26 preferably contain silicon oxide.

[0107] According to such a configuration, for example, when the core layer 22 is processed by an etching method, the first mask layer 24 and the second mask layer 26 can function as an etch stopper. Thereby, precise processing of the core layer 22 by the etching method becomes possible.

[0108] Further, the granule formation step S112 may include a process of forming the granules 4 by an atomic layer deposition method.

[0109] According to such a configuration, the granular material 4 in granular form can be efficiently formed. Further, in the atomic layer deposition method, since the film formation amount can be controlled at the atomic layer level, the particle size of the granular material 4 can be precisely controlled. Furthermore, in the atomic layer deposition method, since the raw material gas and the oxidant can penetrate into the concave portions and holes to form a film, the granular material 4 can also be efficiently formed on the inner wall of the through hole 28. Therefore, according to the atomic layer deposition method, the catalyst structure 1 in which the catalytic active sites C are formed particularly at a high density can be manufactured.

[0110] Further, the first mask layer 24 may have a plurality of openings 25 for exposing the core layer 22. In this case, the laser light irradiation process L is a process of irradiating the core layer 22 with laser light through the openings 25.

[0111] According to such a configuration, in the through hole forming step S108, a plurality of through holes 28 can be simultaneously and easily formed according to the positions of the openings 25.

[0112] Further, the method for manufacturing the catalyst structure according to the embodiment includes a half etching step S104 provided between the preparation step S102 and the laser light irradiation step S106, and performing a half etching process on the core layer 22 corresponding to the openings 25 and 27.

[0113] According to such a configuration, when the core layer 22 is altered in the laser light irradiation step S106, the thickness of the core layer 22 can be reduced in advance. As a result, since the irradiation amount of the laser light can be reduced, the time required for the laser light irradiation step S106 can be shortened.

[0114] Further, when the first metal element is Cu, Pt or In, the second metal element is preferably Zr, Hf, Ta, Zn, Mo or Ti.

[0115] According to such a configuration, the catalyst structure 1 in which the catalytic activity of the catalytic active sites C is particularly enhanced can be manufactured.

[0116] Further, the method for manufacturing the catalyst structure according to the embodiment includes a reduction treatment step S114 provided after the granule formation step S112, which performs a reduction treatment on at least one of the coating 3 and the granules 4.

[0117] According to such a configuration, the catalytic activity can be enhanced. As a result, in at least one of the coating 3 and the granules 4, the oxide is reduced. As a result, the catalytic activity at the catalytic active site C can be enhanced.

[0118] As described above, the catalyst structure and the method for manufacturing the catalyst structure of the present invention have been described based on the preferred embodiments, but the present invention is not limited thereto. For example, the catalyst structure according to the present invention may be one in which each part of the above embodiment is replaced with an arbitrary component having the same function, or an arbitrary component may be added to the above embodiment.

[0119] In addition, the method for manufacturing the catalyst structure of the present invention may be one in which a process for an arbitrary purpose is added to the above embodiment.

Explanation of Reference Numerals

[0120] 1... Catalyst structure, 2... Substrate, 3... Coating, 4... Granules, 20... Substrate, 22... Core layer, 24... First mask layer, 25... Opening, 26... Second mask layer, 27... Opening, 28... Through hole, 29... Concave portion, 31... Altered portion, C... Catalytic active site, E1... Half etching treatment, E2... Etching treatment, L... Laser light irradiation treatment, S102... Preparation step, S104... Half etching step, S106... Laser light irradiation step, S108... Through hole formation step, S110... Coating formation step, S112... Granule formation step, S114... Reduction treatment step

Claims

1. A catalyst structure used in a reforming reaction for reforming a raw material, comprising: a substrate having a core layer, a first mask layer and a second mask layer provided on both sides of the core layer, and a plurality of through-holes penetrating through these layers; a film containing a first metal element and covering the surface of the substrate including the inner walls of the through-holes; a plurality of granular bodies containing a second metal element and contacting the film; The catalyst structure is characterized by comprising the above.

2. The core layer contains silicon, The catalyst structure according to claim 1, wherein the first mask layer and the second mask layer contain silicon oxide.

3. The catalyst structure according to claim 1 or 2, wherein the average inner diameter of the through-holes is 1 μm or more and 300 μm or less.

4. The catalyst structure according to claim 1 or 2, wherein the average thickness of each of the first mask layer and the second mask layer is 0.5 μm or more and 10 μm or less.

5. The catalyst structure according to claim 1 or 2, wherein the average thickness of the film is 1 nm or more and 100 nm or less.

6. The catalyst structure according to claim 1 or 2, wherein the average particle diameter of the granular bodies is 1 nm or more and 100 nm or less.

7. The first metal element is Cu, Pt or In, The catalyst structure according to claim 1 or 2, wherein the second metal element is Zr, Hf, Ta, Zn, Mo or Ti.

8. A method for manufacturing a catalyst structure used in a reforming reaction for reforming a raw material, comprising: a preparation step of preparing a substrate having a core layer, and a first mask layer and a second mask layer provided on both sides of the core layer; a laser light irradiation step of forming a modified portion penetrating through the substrate by performing laser light irradiation treatment on the substrate; a through-hole forming step of removing the modified portion by performing etching treatment on the substrate to form through-holes in the substrate; a film forming step of forming a film containing a first metal element on the surface of the substrate and the inner walls of the through-holes; a granular body forming step of forming a plurality of granular bodies containing a second metal element on the film; The method for manufacturing a catalyst structure is characterized by comprising the above.

9. The core layer contains silicon, The method for manufacturing a catalyst structure according to claim 8, wherein the first mask layer and the second mask layer contain silicon oxide.

10. The method for manufacturing a catalyst structure according to claim 8 or 9, wherein the granular body forming step includes a process of forming the granular bodies by atomic layer deposition.

11. The first mask layer has a plurality of openings for exposing the core layer, The method for manufacturing a catalyst structure according to claim 8 or 9, wherein the laser light irradiation treatment is a treatment of irradiating the core layer with laser light through the openings.

12. The method for manufacturing a catalyst structure according to claim 11, further comprising a half-etching step provided between the preparation step and the laser light irradiation step, the half-etching step being configured to perform a half-etching treatment on the core layer corresponding to the openings.

13. The first metal element is Cu, Pt, or In, The method for manufacturing a catalyst structure according to claim 8 or 9, wherein the second metal element is Zr, Hf, Ta, Zn, Mo, or Ti.

14. The method for manufacturing a catalyst structure according to claim 8, further comprising a reduction treatment step provided after the granule formation step, the reduction treatment step being configured to perform a reduction treatment on at least one of the coating and the granules.

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