Functional structure

Abstract

To provide a functional structure capable of realizing a long life by suppressing functional deterioration of a functional substance.SOLUTION: A functional structure comprises a porous structure carrier composed of a zeolite-type compound and at least one functional substance contained in the carrier. The carrier has passages communicating with each other, the functional substance exists in at least the passages of the carrier, the functional substance contained in the carrier contains a metal element (M), and the content of the metal element (M) is more than 2.5 mass% with respect to the functional structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a functional structure comprising a porous support (skeleton) and a functional substance, and in particular to a functional structure in which a functional substance with a high metal content is present inside the porous skeleton. [Background technology]

[0002] Refineries at petroleum complexes produce a petrochemical raw material called naphtha, as well as various fuels such as heavy oil, diesel, kerosene, gasoline, and LPG from crude oil. Because crude oil is a mixture of the above petrochemical raw materials, various fuels, and various impurities, a process is required to distill and separate the various components contained in the crude oil.

[0003] In the petroleum refining process, the difference in boiling points of each component is utilized to heat crude oil on the trays in the tower of an atmospheric distillation unit to separate each component, and then each separated substance is concentrated. As a result, low-boiling-point substances such as LPG and naphtha are extracted from the upper trays of the atmospheric distillation unit, while high-boiling-point substances such as heavy oil are extracted from the bottom of the atmospheric distillation unit. Various fuel products are then produced by subjecting the separated and concentrated substances to secondary treatment such as desulfurization.

[0004] In general, petroleum reforming catalysts are used in the petroleum refining process to efficiently reform low-boiling naphtha, etc., to produce high-octane gasoline, etc. The naphtha fraction in crude oil has a low octane number as is and is unsuitable as gasoline for running vehicles, so the low-octane paraffin and naphthene components in the naphtha fraction are reformed using petroleum reforming catalysts to convert them into high-octane aromatic components, thereby producing reformed gasoline with properties suitable for vehicle fuel.

[0005] Furthermore, with the increasing heaviness of crude oil, hydrocracking is being carried out to further crack the desulfurized heavy oil and heavy light oil obtained by hydrodesulfurization treatment of heavy oil using hydrodesulfurization units such as direct desulfurization units and indirect desulfurization units, thereby increasing the production of desulfurized naphtha, desulfurized kerosene, and desulfurized light oil. For example, hydrocracking atmospheric distillation residue increases the yield of desulfurized kerosene and light oil fractions and desulfurized naphtha fractions, thereby reducing the desulfurized heavy oil. Furthermore, by using this desulfurized heavy oil in a catalytic cracking unit to produce LPG fractions, FCC gasoline fractions, and LCO fractions, the residual oil is reduced and the light oil fraction is increased. For this purpose, catalysts made of a crystalline aluminosilicate support, a typical example of zeolite, and hydrocracking catalysts containing zeolite and porous inorganic oxides in specific ratios have been proposed.

[0006] For example, a hydrocracking catalyst has been disclosed in which a metal selected from Pd, Pt, Co, Fe, Cr, Mo, W, and mixtures thereof is deposited on the surface of a carrier made of Y-type zeolite (Patent Document 1).

[0007] In the automotive field, a ceramic catalyst body has been proposed as a catalyst structure for exhaust gas from vehicles equipped with diesel engines. The ceramic catalyst body is made by disposing a ceramic carrier on the surface of a substrate ceramic and supporting both a main catalyst component and a promoter catalyst component on the ceramic carrier. In this ceramic catalyst body, a large number of pores consisting of lattice defects in the crystal lattice are formed on the surface of the ceramic carrier made of γ-alumina, and the main catalyst component made of Ce—Zr, Pt, etc. is directly supported near the surface of the ceramic carrier (Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2016 / 0030934 [Patent Document 2] US Patent Application Publication No. 2003 / 0109383 [Patent Document 3] Japanese Patent Application Publication No. 3-502067 [Patent Document 4] Japanese Patent Application Laid-Open No. 2017-128480 [Patent Document 5] International Publication No. 2010 / 097108 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the above-described catalyst structure, because the catalyst particles are supported on or near the surface of the support, they tend to move within the support due to the influence of forces and heat from the fluid, such as the reforming material, during the reforming process, which can easily cause agglomeration (sintering) of catalyst particles. When catalyst particles agglomerate, the effective surface area of ​​the catalyst decreases, which reduces catalytic activity and shortens the catalyst's lifespan. Therefore, the catalyst structure itself must be replaced or regenerated frequently, which is both cumbersome and prevents resource conservation. Furthermore, because petroleum reforming catalysts are typically connected downstream of atmospheric distillation units and used continuously in the petroleum refining process, it is difficult to apply catalyst reactivation techniques. Even if reactivation techniques could be applied, the work would be extremely cumbersome.

[0010] Furthermore, from the viewpoint of practical application, further improvement of catalytic activity is required, and one of the measures to achieve this is to increase the content of catalyst particles. Specifically, Patent Document 3 discloses that the CO conversion rate of the Fischer-Tropsch synthesis reaction (hereinafter referred to as "FT synthesis reaction") improves as the content of cobalt metal particles relative to the catalyst support increases up to about 40%. However, on the other hand, the higher the content of catalyst particles, the more catalyst particles there are on the support surface, making the catalyst particles more likely to aggregate with each other.

[0011] Furthermore, suppressing or preventing the above-mentioned deterioration of functionality over time is a challenge not only in the field of catalysts but also in various other technical fields, and solutions are needed to maintain functionality over the long term. For example, Patent Documents 4 and 5 report a technology for suppressing catalyst aggregation by preparing amorphous silica-coated metal particles using an emulsion method, followed by hydrothermal treatment of these particles to encapsulate the metal particles in zeolite. The preparation of amorphous silica-coated metal particles using the emulsion method involves adding a reducing agent to an emulsion of a surfactant and a metal source in an organic solvent to form metal particles, and then adding a silane coupling agent to form a silica layer on the metal particles. However, when preparing metal particles using the emulsion method, the particle size of the resulting particles is affected by the size of the emulsion droplets and the tendency of the metal particles to aggregate. In general, it is difficult to maintain base metals in nanoparticle form. In fact, in the examples of cited documents 4 and 5, nano-sized particles are only described in the case of precious metal samples, and nano-sized particles are not disclosed for samples of base metals and their oxides, which tend to aggregate. Cited documents 4 and 5 also report that in the emulsion method, organic solvents, surfactants, etc. remain, and the reagents used to form the zeolite structure become impurities, which adversely affect the thermal stability of the zeolite.

[0012] An object of the present invention is to provide a functional structure that can increase the various functions of a functional substance and suppress the deterioration of the function of the functional substance caused by the influence of force, heat, etc., thereby achieving a longer life. [Means for solving the problem]

[0013] As a result of intensive research into achieving the above-mentioned object, the inventors have found that a functional structure comprising a carrier having a porous structure composed of a zeolite-type compound and at least one functional substance present in the carrier, wherein the carrier has passages communicating with each other, the functional substance is present in at least the passages of the carrier, and the functional substance present in the carrier contains a metal element (M), and the content of the metal element (M) is more than 2.5 mass% of the functional structure, thereby increasing the function of the functional substance and suppressing deterioration of the function of the functional substance caused by the influence of force, heat, etc., thereby achieving a functional structure with a longer life, and have completed the present invention based on this finding.

[0014] That is, the gist of the present invention is as follows. [1] A functional structure comprising a porous support made of a zeolite-type compound and at least one functional substance present in the support, wherein the support has passages that communicate with each other, the functional substance is present in at least the passages of the support, the functional substance present in the support contains a metal element (M), and the content of the metal element (M) is more than 2.5 mass% with respect to the functional structure. [2] The functional structure according to [1], wherein the functional substance present in the carrier contains at least one of a metal and a metal oxide. [3] The passages have one of one-dimensional pores, two-dimensional pores, and three-dimensional pores in the framework structure of the zeolite-type compound, and an expanded portion different from any of the one-dimensional pores, the two-dimensional pores, and the three-dimensional pores; and The functional structure according to [1] or [2], characterized in that the functional substance is present at least in the expanded diameter portion. [4] The functional structure according to [3], wherein the enlarged diameter portion connects a plurality of pores that constitute any one of the one-dimensional pores, the two-dimensional pores, and the three-dimensional pores. [5] The functional structure according to [3] or [4], characterized in that the average particle size of the functional substance is larger than the average inner diameter of the passage and equal to or smaller than the inner diameter of the expanded portion. [6] The functional material is a catalytic material, The functional structure according to any one of [1] to [5], wherein the support supports the at least one catalyst substance. [7] The functional structure according to any one of [1] to [6], wherein the average particle size of the functional substance is 0.08 nm to 50 nm. [8] The functional structure according to any one of [1] to [7], wherein the ratio of the average particle size of the functional substance to the average inner diameter of the passages is 0.05 to 500. [9] The functional structure according to any one of [1] to [8], wherein the average inner diameter of the passage is 0.1 nm to 1.5 nm.

[10] The functional structure according to any one of [1] to [9], further comprising at least one other functional substance held on the outer surface of the carrier.

[11] The functional structure according to

[10] , characterized in that the content of the at least one functional substance present in the carrier is greater than the content of the at least one functional substance held on the outer surface of the carrier.

[12] The functional structure according to any one of [1] to

[11] , wherein the zeolite-type compound is a silicate compound.

[13] A method for producing a functional structure, comprising: a calcination step of calcining a precursor material (B) obtained by impregnating a precursor material (A) with a metal-containing solution to obtain a porous support composed of a zeolite-type compound; and a hydrothermal treatment step of adding a structure-directing agent to a precursor material (C) obtained by calcining the precursor material (B) in the presence of a film containing silica particles, and then hydrothermally treating the precursor material (C). [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a functional structure that can suppress the deterioration of the function of a functional substance caused by the influence of force, heat, etc., and thereby realize a longer life. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing the internal structure of a functional structure according to an embodiment of the present invention, in which FIG. 1(a) is a perspective view (partially shown in cross section), and FIG. 1(b) is a partially enlarged cross-sectional view. [Figure 2] 2A and 2B are enlarged partial cross-sectional views for explaining an example of the function of the functional structure of FIG. 1, where FIG. 2A illustrates the sieving function and FIG. 2B illustrates the catalytic function. [Figure 3] FIG. 3 is a flowchart showing an example of a method for manufacturing the functional structure of FIG. [Figure 4] FIG. 4 is a schematic diagram showing a modified example of the functional structure of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0018] [Configuration of functional structures] 1A and 1B are diagrams schematically illustrating the configuration of a functional structure according to an embodiment of the present invention, in which (a) is a perspective view (partially shown in cross section), and (b) is a partially enlarged cross-sectional view. Note that the functional structure in Fig. 1 is merely an example, and the shape, dimensions, etc. of each component according to the present invention are not limited to those in Fig. 1.

[0019] As shown in FIG. 1(a), the functional structure 1 comprises a framework 10, which is a porous support composed of a zeolite-type compound, and at least one functional substance 20 contained within the framework 10.

[0020] The functional material 20 is a material that exerts one or more functions, either alone or in cooperation with the framework 10. Specific examples of the functions include a catalytic function, a light-emitting (or fluorescent) function, a light-absorbing function, and an identification function. The functional material 20 is preferably, for example, a catalytic material having a catalytic function. When the functional material 20 is a catalytic material, the framework 10 is a carrier that supports the catalytic material.

[0021] In the functional structure 1, a plurality of functional materials 20, 20, ... are encapsulated within the porous structure of the skeleton 10. A catalytic material, which is an example of the functional material 20, is preferably at least one of metal oxide fine particles and metal fine particles. Metal oxide fine particles and metal fine particles will be described in detail later. The functional material 20 may also be particles containing a metal oxide, an alloy, or a composite material thereof.

[0022] The skeleton 10 has a porous structure, and as shown in Fig. 1(b), preferably has a plurality of pores 11a, 11a, ... formed therein to form interconnected passages 11. The functional substance 20 is present in at least the passages 11 of the skeleton 10, and is preferably held in at least the passages 11 of the skeleton 10.

[0023] With this configuration, the movement of the functional material 20 within the framework 10 is restricted, and aggregation of the functional materials 20, 20 is effectively prevented. As a result, the reduction in the effective surface area of ​​the functional material 20 can be effectively suppressed, and the function of the functional material 20 is maintained for a long period of time. In other words, the functional structure 1 can suppress the deterioration of the function of the functional material 20 due to aggregation, and the life of the functional structure 1 can be extended. Furthermore, the extended life of the functional structure 1 can reduce the frequency of replacement of the functional structure 1, significantly reducing the amount of used functional structure 1 that is discarded, thereby conserving resources.

[0024] Typically, when a functional structure is used in a fluid (e.g., heavy oil, reformed gas such as NOx, etc.), it may be subjected to an external force from the fluid. In this case, if the functional material is merely held in an adhered state on the outer surface of the skeleton 10, there is a problem that the functional material is easily detached from the outer surface of the skeleton 10 due to the external force from the fluid. In contrast, in the functional structure 1, the functional material 20 is held at least in the passages 11 of the skeleton 10, and therefore the functional material 20 is less likely to detach from the skeleton 10 even when it is affected by the external force from the fluid. That is, when the functional structure 1 is in a fluid, the fluid flows into the passages 11 through the pores 11a of the skeleton 10, and the speed of the fluid flowing through the passages 11 is thought to be slower than the speed of the fluid flowing along the outer surface of the skeleton 10 due to flow resistance (frictional force). Due to the effect of such flow resistance, the pressure that the functional material 20 held in the passages 11 receives from the fluid is lower than the pressure that the functional material receives from the fluid outside the skeleton 10. Therefore, it is possible to effectively prevent the functional substance 20 contained in the skeleton 11 from being released, and to stably maintain the function of the functional substance 20 for a long period of time. Note that the above-mentioned flow path resistance is considered to increase as the passage 11 of the skeleton 10 has multiple bends and branches and the interior of the skeleton 10 has a more complex, three-dimensional structure.

[0025] The content of the metal element (M) in the functional substance is also characterized by being greater than 2.5% by mass relative to the functional structure 1. This allows the function of the functional substance to be obtained more effectively. For example, if the functional substance 20 is a substance having catalytic function, the greater the content of the metal element (M), the higher the frequency of collision and contact between the raw materials for the catalytic reaction and the functional substance 20 present inside the framework 10, resulting in higher catalytic activity. Moreover, even if the content of the metal element (M) is thus high, the movement of the functional substance 20 is restricted as described above, so aggregation between the functional substances 20 can be effectively prevented, and the function of the functional substance 20 can be stably maintained for a long period of time.

[0026] The metal elements (M) contained in the functional structure 1 were quantified using ICP (inductively coupled plasma) alone or a combination of ICP and XRF (X-ray fluorescence analysis). XRF (energy dispersive X-ray fluorescence analyzer "SEA1200VX", manufactured by SSI NanoTechnology) was performed in a vacuum atmosphere at an accelerating voltage of 15 kV (using a Cr filter) or 50 kV (using a Pb filter).

[0027] Furthermore, the passage 11 preferably has one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound, and an expanded diameter portion 12 that is different from any of the one-dimensional pores, the two-dimensional pores, and the three-dimensional pores. In this case, the functional substance 20 is preferably present at least in the expanded diameter portion 12, and more preferably is included in at least the expanded diameter portion 12. The one-dimensional pore here refers to a tunnel-type or cage-type pore that forms a one-dimensional channel, or multiple tunnel-type or cage-type pores (multiple one-dimensional channels) that form multiple one-dimensional channels. The two-dimensional pore refers to a two-dimensional channel in which multiple one-dimensional channels are connected two-dimensionally, and the three-dimensional pore refers to a three-dimensional channel in which multiple one-dimensional channels are connected three-dimensionally.

[0028] This further restricts the movement of the functional substance 20 within the framework 10, making it possible to more effectively prevent the functional substance 20 from detaching and the aggregation of the functional substances 20, 20 together. Inclusion refers to a state in which the functional substance 20 is encapsulated in the framework 10. In this case, the functional substance 20 and the framework 10 do not necessarily need to be in direct contact with each other, and the functional substance 20 may be indirectly held in the framework 10 with another substance (for example, a surfactant) interposed between the functional substance 20 and the framework 10.

[0029] 1(b) shows a case where the functional substance 20 is encapsulated in the enlarged diameter portion 12, but the present invention is not limited to this configuration, and the functional substance 20 may be held in the passage 11 with a portion of it protruding outside the enlarged diameter portion 12. The functional substance 20 may also be partially embedded in a portion of the passage 11 other than the enlarged diameter portion 12 (for example, the inner wall portion of the passage 11), or may be held by adhesion or the like.

[0030] Furthermore, it is preferable that the expanded diameter portion 12 connects the plurality of holes 11a, 11a constituting any one of the one-dimensional, two-dimensional, and three-dimensional holes, with each other, thereby providing a separate passage different from the one-dimensional, two-dimensional, or three-dimensional holes inside the framework 10, thereby enabling the functional substance 20 to exhibit its functions more effectively.

[0031] Furthermore, the passage 11 is formed three-dimensionally inside the framework 10, including a branching portion or a junction portion, and the enlarged diameter portion 12 is preferably provided at the branching portion or the junction portion of the passage 11.

[0032] The average inner diameter D of the passage 11 formed in the skeleton 10 F is calculated from the average value of the minor axis and the major axis of the pores 11a constituting any one of the one-dimensional pores, the two-dimensional pores, and the three-dimensional pores, and is, for example, 0.1 nm to 1.5 nm, preferably 0.3 nm to 0.8 nm. E The inner diameter D of the expanded diameter portion 12 is, for example, 0.5 nm to 50 nm, preferably 1.1 nm to 40 nm, and more preferably 1.1 nm to 3.3 nm. E is, for example, the pore diameter of the precursor material (A) described later and the average particle diameter D of the functional substance 20 to be enclosed. C The inner diameter D of the expanded diameter portion 12 depends on E is a size that can encapsulate the functional substance 20.

[0033] The framework 10 is composed of a zeolite-type compound. Examples of zeolite-type compounds include silicate compounds such as zeolite (aluminosilicate), cation-exchanged zeolite, and silicalite, zeolite-related compounds such as aluminoborates, aluminoarsenates, and germanates, and phosphate-based zeolite-like substances such as molybdenum phosphate. Among these, silicate compounds are preferred as the zeolite-type compounds.

[0034] The framework structure of the zeolite compound is selected from FAU type (Y type or X type), MTW type, MFI type (ZSM-5), FER type (ferrierite), LTA type (A type), MWW type (MCM-22), MOR type (mordenite), LTL type (L type), BEA type (beta type), etc., with MFI type being preferred, and ZSM-5 being more preferred. Zeolite compounds have multiple pores with pore sizes corresponding to their framework structures; for example, the maximum pore size of MFI type is 0.636 nm (6.36 Å) and the average pore size is 0.560 nm (5.60 Å).

[0035] Hereinafter, a detailed description will be given of the case where the functional material 20 is at least one of metal oxide fine particles and metal fine particles (hereinafter, these may be collectively referred to as "fine particles").

[0036] When the functional material 20 is the above-mentioned fine particles, the fine particles 20 may be primary particles or secondary particles formed by aggregation of the primary particles. C is preferably the average inner diameter D of the passage 11 F and the inner diameter D of the expanded diameter portion 12 is larger than E The following is true (D F <D C ≦D E). Such microparticles 20 are preferably enclosed in the enlarged diameter portions 12 within the passages 11, and movement of the microparticles 20 within the skeleton 10 is restricted. Therefore, even when the microparticles 20 are subjected to an external force from the fluid, movement of the microparticles 20 within the skeleton 10 is restricted, and contact between the microparticles 20 enclosed in the enlarged diameter portions 12, 12, distributed and arranged in the passages 11 of the skeleton 10 can be effectively prevented.

[0037] When the functional material 20 is metal oxide fine particles, the average particle diameter D of the metal oxide fine particles 20 C In both the primary particles and secondary particles, the average inner diameter D of the passages 11 is preferably 0.1 nm to 50 nm, more preferably 0.1 nm or more and less than 30 nm, even more preferably 0.4 nm to 14.0 nm, and particularly preferably 1.0 nm to 3.3 nm. F Average particle size D of metal oxide fine particles 20 C The ratio (D C / D F ) is preferably 0.06 to 500, more preferably 0.1 to 36, still more preferably 1.1 to 36, and particularly preferably 1.7 to 4.5.

[0038] Furthermore, when the functional material 20 is metal oxide microparticles, the metal element (M) of the metal oxide microparticles is preferably contained in an amount of more than 2.5 mass% and not more than 7.55 mass% relative to the functional structure 1, more preferably more than 2.5 mass% and not more than 6.86 mass%, and even more preferably more than 3.4 mass% and not more than 6.86 mass%. For example, when the metal element (M) is Co, the content (mass%) of the Co element is expressed as (mass of Co element) / (mass of all elements in the functional structure 1)×100.

[0039] The metal oxide microparticles may be composed of any metal oxide, and may be composed of, for example, a single metal oxide or a mixture of two or more metal oxides. In this specification, the term "metal oxide" (as a material) constituting the metal oxide microparticles means a metal oxide containing one metal element (M) and a metal composite oxide containing two or more metal elements (M), and is a general term for oxides containing one or more metal elements (M).

[0040] Examples of such metal oxides include cobalt oxide (CoO x ), nickel oxide (NiO x ), iron oxide (FeO x ), copper oxide (CuO x ), zirconium oxide (ZrO x ), cerium oxide (CeO x ), aluminum oxide (AlO x ), niobium oxide (NbO x ), titanium oxide (TiO x ), bismuth oxide (BiO x ), molybdenum oxide (MoO x ), vanadium oxide (VO x ), chromium oxide (CrO x ) and the like, and it is preferable to use one or more of the above as the main component.

[0041] In addition, when the functional material 20 is metal fine particles, the average particle diameter D C In both the primary particles and secondary particles, the average inner diameter D of the passages 11 is preferably 0.08 to 30 nm, more preferably 0.08 nm or more and less than 25 nm, even more preferably 0.4 nm to 11.0 nm, and particularly preferably 0.8 to 2.7 nm. F Average particle size D of metal particles 20 C The ratio (D C / D F ) is preferably 0.05 to 300, more preferably 0.1 to 30, even more preferably 1.1 to 30, and particularly preferably 1.4 to 3.6.

[0042] When the functional material 20 is a metal microparticle, the metal element (M) of the metal microparticle is preferably contained in an amount of more than 2.5 mass% and not more than 7.55 mass% relative to the functional structure 1, more preferably more than 2.5 mass% and not more than 6.86 mass%, and even more preferably more than 3.4 mass% and not more than 6.86 mass%.

[0043] The metal microparticles may be made of any non-oxidized metal, and may be made of, for example, a single metal, or an alloy or mixture formed of two or more metals. In this specification, the term "metal" (as a material) constituting the metal microparticles means a single metal containing one metal element (M) and an alloy or mixture formed of two or more metal elements (M), and is a general term for metals containing one or more metal elements.

[0044] Examples of such metals include platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni), cobalt (Co), molybdenum (Mo), tungsten (W), iron (Fe), chromium (Cr), cerium (Ce), copper (Cu), magnesium (Mg), and aluminum (Al), and it is preferable to use one or more of the above as the main component.

[0045] From the viewpoint of durability, the functional material 20 is preferably metal oxide fine particles.

[0046] Furthermore, the ratio of silicon (Si) constituting the framework 10 to the metal element (M) constituting the microparticles 20 (atomic ratio Si / M) is preferably 10 to 1000, more preferably 25 to 100. If the ratio is greater than 1000, the activity may be low and the function as a functional substance may not be fully achieved. On the other hand, if the ratio is less than 10, the proportion of the microparticles 20 becomes too large, and the strength of the framework 10 tends to decrease. Note that the microparticles 20 referred to here refer to microparticles held or supported inside the framework 10, and do not include microparticles attached to the outer surface of the framework 10.

[0047] [Functions of functional structures] As described above, the functional structure 1 includes a porous skeleton 10 and at least one functional material 20 contained within the skeleton. When the functional material 20 contained within the skeleton comes into contact with a fluid, the functional structure 1 exhibits a function corresponding to the functional material 20. Specifically, a fluid that comes into contact with the outer surface 10a of the functional structure 1 flows into the skeleton 10 through the pores 11a formed in the outer surface 10a, is guided into the passages 11, travels through the passages 11, and exits the functional structure 1 through other pores 11a. As the fluid travels through the passages 11, it comes into contact with the functional material 20 held in the passages 11, causing a reaction (e.g., a catalytic reaction) corresponding to the function of the functional material 20. Furthermore, the functional structure 1 has a molecular sieving ability due to the porous structure of the skeleton.

[0048] First, the molecular sieving ability of the functional structure 1 will be described with reference to FIG. 2(a) using an example in which the fluid is a liquid containing benzene, propylene, and mesitylene. As shown in FIG. 2(a), compounds (e.g., benzene, propylene) composed of molecules having a size equal to or smaller than the pore size of the pores 11a, in other words, equal to or smaller than the inner diameter of the passages 11, can penetrate into the framework 10. On the other hand, compounds (e.g., mesitylene) composed of molecules having a size larger than the pore size of the pores 11a cannot penetrate into the framework 10. In this way, when the fluid contains multiple types of compounds, the reaction of the compounds that cannot penetrate into the framework 10 is restricted, and the compounds that can penetrate into the framework 10 can be reacted.

[0049] Of the compounds produced in the framework 10 by the reaction, only compounds composed of molecules having a size equal to or smaller than the pore diameter of the pores 11a can escape to the outside of the framework 10 through the pores 11a and are obtained as reaction products. On the other hand, compounds that cannot escape to the outside of the framework 10 through the pores 11a can be escaped to the outside of the framework 10 by converting them into compounds composed of molecules of a size that can escape to the outside of the framework 10. In this way, by using the functional structure 1, a specific reaction product can be selectively obtained.

[0050] In the functional structure 1, as shown in FIG. 2(b), the functional substance 20 is preferably enclosed in the expanded diameter portion 12 of the passage 11. The average particle diameter D of the functional substance 20 is C is the average inner diameter D of the passage 11. F The inner diameter D of the expanded diameter portion 12 is larger than E If it is smaller than (D F <D C <D E ), a small passage 13 is formed between the functional substance 20 and the enlarged diameter portion 12. As shown by the arrow in FIG. 2(b), the fluid that has entered the small passage 13 comes into contact with the functional substance 20. Because each functional substance 20 is encapsulated in the enlarged diameter portion 12, its movement within the framework 10 is restricted. This prevents aggregation of the functional substances 20 within the framework 10. As a result, a large contact area between the functional substance 20 and the fluid can be stably maintained.

[0051] Next, a case where the functional material 20 has a catalytic function will be described. As a specific example, when the functional material 20 is iron oxide (FeO x) microparticles, and an example will be described in which dodecylbenzene, a heavy oil, is infiltrated into the framework 10 of the functional structure 1. When dodecylbenzene infiltrates the framework 10, it is decomposed into various alcohols and ketones by an oxidative decomposition reaction, as shown below. Furthermore, benzene, a light oil, is produced from ketones (acetophenone in this case), one of the decomposition products. This means that the functional material 20 functions as a catalyst in the oxidative decomposition reaction. In this way, heavy oil can be converted into light oil by using the functional structure 1. Conventionally, hydrocracking using hydrogen was used to convert heavy oil into light oil. In contrast, the use of the functional structure 1 eliminates the need for hydrogen. Therefore, it can be used to convert heavy oil into light oil even in areas where hydrogen supply is difficult. Furthermore, eliminating the need for hydrogen reduces costs and is expected to promote the use of heavy oil, which has not been fully utilized until now.

[0052] [ka] [ka]

[0053] Next, a case where the functional material 20 has a catalytic function will be described. Specifically, when the functional material 20 is iron (Fe) fine particles, the functional structure 1 can be used as a catalyst for, for example, an FT synthesis reaction. This FT synthesis reaction is a reaction in which liquid hydrocarbons are synthesized from carbon monoxide and hydrogen using a catalytic reaction, and is roughly represented by the following formula: (2n+1)H2+nCO→C n H 2n+2 +nH2O

[0054] [Method for producing the functional structure of the first embodiment] Fig. 3 is a flowchart showing a method for producing the functional structure 1 of Fig. 1. Hereinafter, an example of the method for producing the functional structure will be described, taking as an example a case where the functional substance present in the framework is metal oxide fine particles.

[0055] (Step S1: Preparation process) First, a precursor material (A) for obtaining a porous structure framework composed of a zeolite-type compound is prepared, as shown in Figure 3. The precursor material (A) is preferably a regular mesoporous substance, and can be selected appropriately depending on the type (composition) of the zeolite-type compound that constitutes the framework of the functional structure.

[0056] When the zeolite-type compound constituting the framework of the functional structure is a silicate compound, the ordered mesoporous material is preferably a compound having an Si—O framework in which pores with diameters of 1 to 50 nm are uniformly sized and regularly developed in one, two, or three dimensions. Such ordered mesoporous materials can be obtained as various synthetic products depending on the synthesis conditions. Specific examples of synthetic products include SBA-1, SBA-15, SBA-16, KIT-6, FSM-16, and MCM-41, with MCM-41 being preferred. The pore diameters of SBA-1 are 10 to 30 nm, SBA-15 are 6 to 10 nm, SBA-16 are 6 nm, KIT-6 are 9 nm, FSM-16 are 3 to 5 nm, and MCM-41 are 1 to 10 nm. Examples of such regular mesoporous materials include mesoporous silica, mesoporous aluminosilicate, and mesoporous metallosilicate.

[0057] The precursor material (A) may be either a commercially available product or a synthetic product. The precursor material (A) can be synthesized using a known method for synthesizing ordered mesoporous materials. For example, a mixed solution containing raw materials containing the constituent elements of the precursor material (A) and a templating agent for defining the structure of the precursor material (A) is prepared, the pH is adjusted as necessary, and hydrothermal treatment (hydrothermal synthesis) is performed. The precipitate (product) obtained by the hydrothermal treatment is then recovered (e.g., filtered), washed and dried as necessary, and calcined to obtain the powdered ordered mesoporous material, precursor material (A). The solvent for the mixed solution can be, for example, water, an organic solvent such as alcohol, or a mixture thereof. The raw materials are selected depending on the type of framework, and examples include silica agents such as tetraethoxysilane (TEOS), fumed silica, and quartz sand. Furthermore, various surfactants, block copolymers, etc. can be used as templating agents, and it is preferable to select one depending on the type of ordered mesoporous material synthesized. For example, when preparing MCM-41, a surfactant such as hexadecyltrimethylammonium bromide is suitable. The hydrothermal treatment can be carried out, for example, in a sealed container under treatment conditions of 80 to 800°C, 5 to 240 hours, and 0 to 2000 kPa. The calcination treatment can be carried out, for example, in air under treatment conditions of 350 to 850°C, and 2 to 30 hours.

[0058] (Step S2: Impregnation process) Next, the prepared precursor material (A) is impregnated with a metal-containing solution to obtain precursor material (B).

[0059] The metal-containing solution may be any solution containing a metal component (e.g., metal ion) corresponding to the metal element (M) constituting the metal oxide microparticles of the functional structure, and can be prepared, for example, by dissolving a metal salt containing the metal element (M) in a solvent. Examples of such metal salts include chlorides, hydroxides, oxides, sulfates, and nitrates, with nitrates being preferred. The solvent may be, for example, water, an organic solvent such as alcohol, or a mixture thereof.

[0060] The method for impregnating the precursor material (A) with the metal-containing solution is not particularly limited. For example, it is preferable to add the metal-containing solution in small amounts in multiple batches while stirring the powdered precursor material (A) before the calcination step described below. Furthermore, from the viewpoint of making it easier for the metal-containing solution to penetrate into the pores of the precursor material (A), it is preferable to add a surfactant as an additive to the precursor material (A) before adding the metal-containing solution. It is believed that such an additive serves to coat the outer surface of the precursor material (A), preventing the metal-containing solution added thereafter from adhering to the outer surface of the precursor material (A), thereby making it easier for the metal-containing solution to penetrate into the pores of the precursor material (A).

[0061] Examples of such additives include nonionic surfactants such as polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenyl ether. These surfactants have large molecular sizes and cannot penetrate the pores of the precursor material (A). Therefore, they do not adhere to the pores and do not prevent the metal-containing solution from penetrating the pores. A preferred method for adding the nonionic surfactant is to add 50 to 500% by mass of the nonionic surfactant to the precursor material (A) before the firing step described below. If the amount of the nonionic surfactant added to the precursor material (A) is less than 50% by mass, the suppression effect described above is not readily achieved. However, adding more than 500% by mass of the nonionic surfactant to the precursor material (A) is undesirable because the viscosity increases excessively. Therefore, the amount of the nonionic surfactant added to the precursor material (A) is set to a value within the above range.

[0062] Furthermore, the amount of metal-containing solution added to precursor material (A) is preferably adjusted appropriately, taking into consideration the amount of metal element (M) contained in the metal-containing solution impregnated into precursor material (A) (i.e., the amount of metal element (M) to be incorporated into precursor material (B)). For example, before the calcination step described below, the amount of metal-containing solution added to precursor material (A) is preferably adjusted so that the ratio of silicon (Si) constituting precursor material (A) to the metal element (M) contained in the metal-containing solution added to precursor material (A) (atomic ratio Si / M) is 10 to 1000, more preferably 25 to 100. For example, when a surfactant is added as an additive to precursor material (A) before the metal-containing solution is added to precursor material (A), the amount of metal-containing solution added to precursor material (A) is adjusted to an atomic ratio Si / M of 25 to 100, thereby allowing the metal element (M) of the metal oxide fine particles to be contained in an amount of at least more than 2.5% by mass relative to the functional structure. The amount of metal element (M) present inside the pores of precursor material (B) is roughly proportional to the amount of metal-containing solution added to precursor material (A), provided that the metal concentration of the metal-containing solution, the presence or absence of the additive, and other conditions such as temperature and pressure are the same. Furthermore, the amount of metal element (M) present in precursor material (B) is proportional to the amount of metal element constituting the metal oxide microparticles present in the framework of the functional structure. Therefore, by controlling the amount of metal-containing solution added to precursor material (A) within the above range, the metal-containing solution can be sufficiently impregnated into the pores of precursor material (A), and thus the amount of metal oxide microparticles present in the framework of the functional structure can be adjusted.

[0063] After the precursor material (A) has been impregnated with the metal-containing solution, it may be washed if necessary. The washing solution may be water, an organic solvent such as alcohol, or a mixture of these. Furthermore, after the precursor material (A) has been impregnated with the metal-containing solution and washed if necessary, it is preferable to further perform a drying process. Examples of the drying process include natural drying overnight or high-temperature drying at 150°C or less. If the calcination process described below is performed while a large amount of water from the metal-containing solution or the washing solution remains in the precursor material (A), the framework structure of the ordered mesoporous material of the precursor material (A) may be destroyed, so thorough drying is preferable.

[0064] (Step S3: Firing process) Next, precursor material (A) for obtaining a porous framework composed of a zeolite-type compound is impregnated with a metal-containing solution to obtain precursor material (B), which is then calcined to obtain precursor material (C).

[0065] The calcination treatment is preferably carried out in air at 350 to 850°C for 2 to 30 hours, for example. Such calcination treatment causes crystal growth of the metal component impregnated in the pores of the ordered mesoporous material, forming metal oxide fine particles in the pores.

[0066] (Step S4: Hydrothermal treatment process) Next, a mixed solution is prepared by mixing the precursor material (C) with a structure-directing agent, and the precursor material (B) is calcined to obtain the precursor material (C), which is then subjected to a hydrothermal treatment to obtain a functional structure.

[0067] The structure-directing agent is a templating agent for defining the skeletal structure of the skeleton of the functional structure, and a surfactant can be used, for example. The structure-directing agent is preferably selected according to the skeletal structure of the skeleton of the functional structure, and suitable examples include surfactants such as tetramethylammonium bromide (TMABr), tetraethylammonium bromide (TEABr), and tetrapropylammonium bromide (TPABr). These are usually referred to as organic structure directing agents (OSDA).

[0068] The precursor material (C) and the structure-directing agent may be mixed during the hydrothermal treatment step or before the hydrothermal treatment step. The method for preparing the mixed solution is not particularly limited. The precursor material (C), the structure-directing agent, and the solvent may be mixed simultaneously, or the precursor material (C) and the structure-directing agent may be dispersed in separate solutions in the solvent, and then the respective dispersion solutions may be mixed. Examples of solvents that can be used include water, organic solvents such as alcohols, and mixtures of these. It is preferable to adjust the pH of the mixed solution using an acid or base before the hydrothermal treatment.

[0069] If the hydrolysis rate of the precursor material (C) is too fast, the metal oxide particles will leak out from the interior, making it difficult to encapsulate them within the zeolite. If the hydrolysis rate is too slow, it will be difficult to form a zeolite. Therefore, it is necessary to adjust the hydrolysis rate appropriately depending on the amount of metal to be encapsulated. The hydrolysis rate can be adjusted using any one of the following methods, such as adjusting the temperature during synthesis, adjusting the pH of the synthesis solution, or extending the synthesis time, or a combination of these methods.

[0070] The hydrothermal treatment can be carried out by taking the above points into consideration in relation to known methods, and is preferably carried out, for example, in a sealed container under treatment conditions of 80 to 800°C, 5 to 240 hours, and 0 to 2000 kPa. The hydrothermal treatment is also preferably carried out in a basic atmosphere.

[0071] Although the reaction mechanism here is not entirely clear, by performing hydrothermal treatment using precursor material (C) as a raw material, the skeletal structure of precursor material (C) as a regular mesoporous substance gradually collapses, but the position of the metal oxide microparticles inside the pores of precursor material (C) is largely maintained, and a new skeletal structure (porous structure) is formed as the skeleton of the functional structure due to the action of the structure-directing agent. The functional structure obtained in this way comprises a porous skeleton and metal oxide microparticles contained within the skeleton, and further, the skeleton has a plurality of pores that are interconnected due to the porous structure, and at least a portion of the metal oxide microparticles are held in the skeleton passages.

[0072] Furthermore, in the present embodiment, in the hydrothermal treatment step, a mixed solution is prepared by mixing the precursor material (C) with a structure-directing agent, and the precursor material (C) is hydrothermally treated. However, this is not limiting, and the precursor material (C) may be hydrothermally treated without mixing the precursor material (C) with a structure-directing agent.

[0073] The precipitate (functional structure) obtained after the hydrothermal treatment is preferably recovered (e.g., filtered) and then washed, dried, and calcined as necessary. Examples of washing solutions include water, organic solvents such as alcohol, or a mixture of these. Examples of drying treatments include natural drying overnight or high-temperature drying at 150°C or lower. If the precipitate is calcined while a large amount of moisture remains, the skeleton structure of the functional structure may be destroyed, so thorough drying is preferred. Calcination can be performed, for example, in air at 350 to 850°C for 2 to 30 hours. Such calcination burns off the structure-directing agent attached to the functional structure. Depending on the intended use, the recovered precipitate can be used as is without calcination. For example, if the functional structure is used in a high-temperature, oxidizing environment, exposing the functional structure to the environment for a certain period of time burns off the structure-directing agent, resulting in a functional structure similar to that obtained after calcination, allowing it to be used as is.

[0074] [Method for producing the functional structure of the second embodiment] The method for producing a functional structure according to the second aspect of the present invention is characterized by comprising a calcination step of calcining precursor material (B) obtained by impregnating precursor material (A) with a metal-containing solution to obtain a porous support composed of a zeolite-type compound, and a hydrothermal treatment step of adding a structure-directing agent to precursor material (C) obtained by calcining precursor material (B) in the presence of a film containing silica particles, and subjecting the precursor material to hydrothermal treatment.

[0075] The only differences from the method for producing a functional structure according to the second aspect of the present invention described above are that in the impregnation step, the amount of metal-containing solution added to the precursor material (A) before the firing step can be adjusted so that the ratio of silicon (Si) constituting the precursor material (A) to the metal element (M) contained in the metal-containing solution added to the precursor material (A) (atomic number ratio Si / M) is 10 to 1000, and that in the hydrothermal treatment step, the hydrothermal treatment is performed in the presence of a film containing silica particles.

[0076] In this way, by performing hydrothermal treatment in the presence of a film containing silica particles, part of the silicon, which is the raw material for the hydrothermal treatment, is consumed by the growth of silica particles under hydrothermal conditions, resulting in a relatively high content of metal element (M).

[0077] The silica film may be attached to the inner wall of a vessel (e.g., an autoclave) used for the hydrothermal treatment, or may be attached to a substrate that is difficult to dissolve under hydrothermal conditions and added to the mixed solution, or the silica film may be added as is if it has sufficient strength. The thickness of the silica film is not particularly limited, but a thickness of 0.1 μm to 1.0 μm is preferred. If the silica film is thinner than 0.1 μm, less silicon is used for growing silica particles, and the silica source may not be sufficiently consumed for growing the silica film. Furthermore, if the silica film is thicker than 1.0 μm, it may take a long time to form the silica film.

[0078] The above describes a method for producing a functional structure in which the functional substance is metal oxide microparticles. However, a functional structure can also be produced in a similar manner when the functional substance is metal microparticles. For example, after obtaining a functional structure containing metal oxide particles as described above, a reduction treatment can be performed under a reducing gas atmosphere such as hydrogen gas to obtain a functional structure in which metal microparticles are embedded in a framework. In this case, the metal oxide microparticles embedded in the framework are reduced to form metal microparticles corresponding to the metal element (M) constituting the metal oxide microparticles. Alternatively, by using a metal element (M) that is difficult to oxidize (e.g., a noble metal) as the metal element (M) contained in the metal-containing solution impregnated into the precursor material (A), crystal growth of the metal microparticles can be achieved in the calcination step (step S3), and then a hydrothermal treatment can be performed to obtain a functional structure in which metal microparticles are embedded in a framework.

[0079] [Modification of Functional Structure 1] FIG. 4 is a schematic diagram showing a modified example of the functional structure 1 of FIG. The functional structure 1 in Figure 1 is shown to have a skeleton 10 and a functional substance 20 contained within the skeleton 10, but is not limited to this configuration.For example, as shown in Figure 4, the functional structure 2 may further have another functional substance 30 held on the outer surface 10a of the skeleton 10.

[0080] This functional substance 30 is a substance that exhibits one or more functions. The function possessed by the other functional substance 30 may be the same as or different from the function possessed by the functional substance 20. Specific examples of the function possessed by the other functional substance 30 are the same as those described for the functional substance 20, and among them, it is preferable that the other functional substance 30 has a catalytic function, in which case the functional substance 30 is a catalytic substance. Furthermore, when both the functional substances 20 and 30 are substances having the same function, the material of the other functional substance 30 may be the same as or different from the material of the functional substance 20. According to this configuration, the content of the functional substance held in the functional structure 2 can be increased, and the function of the functional substance can be further promoted.

[0081] In this case, it is preferable that the content of the functional substance 20 present inside the skeleton 10 is greater than the content of the other functional substances 30 held on the outer surface 10a of the skeleton 10. This allows the function of the functional substance 20 held inside the skeleton 10 to predominate, and the function of the functional substance is stably exerted.

[0082] Although the functional structure according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and changes are possible based on the technical concept of the present invention. [Example]

[0083] Examples 1 to 4 [Synthesis of precursor material (A)] A mixed aqueous solution was prepared by mixing a silica agent (tetraethoxysilane (TEOS), manufactured by Wako Pure Chemical Industries, Ltd.) with a surfactant as a template agent. The pH was adjusted appropriately and the solution was subjected to hydrothermal treatment in a sealed container at 80 to 350°C for 100 hours. The resulting precipitate was then filtered, washed with water and ethanol, and calcined in air at 550°C for 24 hours to obtain precursor material (A) with the type and pore size shown in Table 1. The following surfactants were used depending on the type of precursor material (A) ("Type of precursor material (A): Surfactant"). MCM-41: Hexadecyltrimethylammonium bromide (CTAB) (Wako Pure Chemical Industries, Ltd.)

[0084] [Preparation of precursor materials (B) and (C)] Next, metal-containing aqueous solutions were prepared by dissolving metal salts containing the metal elements (M) constituting the metal oxide microparticles of the types shown in Table 1 in water. The metal salts used were as follows, depending on the type of metal oxide microparticles ("metal oxide microparticles: metal salt"). CoO x Cobalt(II) nitrate hexahydrate (Wako Pure Chemical Industries, Ltd.) NiOx: Nickel (II) nitrate hexahydrate (Wako Pure Chemical Industries, Ltd.)

[0085] Next, the metal-containing aqueous solution was added in small amounts in multiple batches to the powdered precursor material (A), and the mixture was dried at room temperature (20°C ± 10°C) for 12 hours or more to obtain the precursor material (B).

[0086] When the additive condition shown in Table 1 was "Yes," a pretreatment was performed by adding an aqueous solution of polyoxyethylene (15) oleyl ether (NIKKOL BO-15V, manufactured by Nikko Chemicals Co., Ltd.) as an additive to the precursor material (A) before adding the metal-containing aqueous solution, and then the metal-containing aqueous solution was added as described above. When the additive condition was "No," the pretreatment with the additive as described above was not performed.

[0087] In addition, the amount of metal-containing aqueous solution added to the precursor material (A) was adjusted so that the ratio of silicon (Si) constituting the precursor material (A) to the metal element (M) contained in the metal-containing aqueous solution (atomic number ratio Si / M) would be the value shown in Table 1.

[0088] Next, the precursor material (B) impregnated with the metal-containing aqueous solution obtained as described above was calcined in air at 550° C. for 24 hours to obtain a precursor material (C).

[0089] [Synthesis of functional structures] The precursor material (C) obtained as described above was mixed with a structure-directing agent to prepare a mixed aqueous solution, which was then subjected to hydrothermal treatment in a sealed container at 80 to 350°C under the conditions of pH and time shown in Table 1. In Example 3, a sealed container was used in which silica particles had adhered to the inner wall to a thickness of 0.1 to 0.2 mm. The resulting precipitate was then filtered, washed with water, dried at 100°C for 12 hours or more, and then calcined in air at 600°C for 24 hours to obtain functional structures having a framework and metal oxide fine particles as a functional substance shown in Table 1 (Examples 1 to 4).

[0090] (Comparative Example 1) In Comparative Example 1, an MFI type silicalite (functional structure C1) was synthesized in the same manner as in Example 1, except that the step of adhering cobalt oxide fine particles was omitted.

[0091] (Comparative Example 2) In Comparative Example 2, MFI-type silicalite was mixed with cobalt oxide powder (II, III) (manufactured by Sigma-Aldrich Japan LLC) having an average particle size of 50 nm or less, and functional structure C2 was obtained in which cobalt oxide fine particles were attached as a functional substance to the outer surface of the silicalite as a framework. MFI-type silicalite was synthesized in the same manner as in Comparative Example 1.

[0092] (Comparative Example 3) In Comparative Example 3, a functional structure C3 was synthesized in the same manner as in Example 1, except that the ratio of silicon (Si) constituting the precursor material (A) (atomic ratio Si / M) was set to 100.

[0093] [evaluation] The functional structures of the above-mentioned Examples and the functional structures C1 to C3 of the Comparative Examples were subjected to various property evaluations under the conditions shown below.

[0094] [A] Cross-sectional observation Observation samples were prepared by a pulverization method for the functional structures of the above-mentioned Examples and the functional structures C1 to C3 of the Comparative Examples, and cross-sections were observed using a transmission electron microscope (TEM) (TITAN G2, manufactured by FEI).

[0095] As a result, it was confirmed that the functional structure of the above-mentioned Examples and the functional structure C3 contained and retained the functional substance inside the zeolite framework. On the other hand, the functional structure C1 of Comparative Example 1 did not contain the functional substance. Furthermore, the functional structure C2 of Comparative Example 2 contained the functional substance only attached to the outer surface of the framework, but not inside the framework.

[0096] Furthermore, for the functional structures in the above Example and Comparative Example 3 in which the metal oxide was cobalt oxide fine particles (CoOx), cross sections were cut out by FIB (focused ion beam) processing, and cross-sectional elemental analysis was performed using an SEM (SU8020, manufactured by Hitachi High-Technologies Corporation) and an EDX (X-Max, manufactured by Horiba, Ltd.) As a result, Co element was detected from inside the framework.

[0097] The results of the cross-sectional observations using TEM and SEM / EDX confirmed the presence of cobalt oxide fine particles inside the framework.

[0098] [B] Average inner diameter of the pathways in the framework and average particle size of the functional material In the TEM image taken by the cross-sectional observation performed in the above evaluation [A], 500 passages of the skeleton were randomly selected, and the long and short diameters of each were measured. The inner diameter of each was calculated from the average value (N=500). The average inner diameter was then calculated to obtain the average inner diameter D of the passages of the skeleton. F Similarly, for the functional substance, 500 particles of the functional substance were randomly selected from the TEM image, and the particle size of each was measured (N=500), and the average value was calculated to obtain the average particle size D of the functional substance. C The results are shown in Table 1.

[0099] In addition, SAXS (small-angle X-ray scattering) was used to analyze the average particle size and dispersion state of the functional material. SAXS measurements were performed using the beamline BL19B2 at Spring-8. The obtained SAXS data was fitted to a spherical model using the Guinier approximation method to calculate the particle size. The particle size was measured for a functional structure in which the metal oxide was cobalt oxide microparticles. For comparison, commercially available cobalt oxide microparticles (manufactured by Wako) were also observed and measured using an SEM.

[0100] As a result, while the commercially available product contained randomly distributed cobalt oxide microparticles of various sizes in the particle size range of approximately 50 nm to 400 nm, the functional structures of each example detected scattering peaks with particle sizes of 10 nm or less, corresponding to the values ​​of each example in Table 1. Furthermore, the SAXS measurement results showed that functional substances with particle sizes of 10 nm or less were present within the framework in a uniform and highly dispersed state.

[0101] [C] Relationship between the amount of metal-containing solution added and the amount of metal contained A functional structure was prepared in which metal oxide microparticles were encapsulated within the framework with an added amount of Si / M=50 (M=Co), and then the amount of metal (mass%) encapsulated within the framework of the functional structure prepared with the above added amount was measured. Metal content was determined by ICP (inductively coupled plasma) and a combination of ICP and X-ray fluorescence analysis (XRF). XRF (energy dispersive X-ray fluorescence analyzer "SEA1200VX" manufactured by SSI NanoTechnology) was performed in a vacuum atmosphere at an accelerating voltage of 15 kV (using a Cr filter) or 50 kV (using a Pb filter). XRF is a method for calculating the amount of metal present from the fluorescence intensity, and a quantitative value (in terms of mass %) cannot be calculated using XRF alone. Therefore, the amount of metal in a functional structure synthesized by adding metal at Si / M=100 was quantified by ICP analysis using a standard sample. The content of cobalt element was 1.3 mass %. (Comparative Example 3) The functional structures in the examples were measured by XRF, and the amount of metal contained was calculated using the following formula.

[0102] Metal content of functional structure [wt%] = ICP measurement value of standard sample [wt%] × (XRF count value of functional structure [cps] / XRF count value of standard sample [cps])

[0103] As a result, it was found that the higher the metal content, the higher the conversion rate of the FT synthesis reaction.

[0104] [D] Content of metal element (M) in functional structure Metal content was determined using either ICP (inductively coupled plasma) alone or a combination of ICP and XRF (X-ray fluorescence analysis). XRF (energy dispersive X-ray fluorescence analyzer "SEA1200VX" manufactured by SSI NanoTechnology) was performed in a vacuum atmosphere at an accelerating voltage of 15 kV (using a Cr filter) or 50 kV (using a Pb filter).

[0105] [E] Performance evaluation The catalytic ability (performance) of the functional substance (catalytic substance) was evaluated for the functional structures of the above-mentioned Examples and the functional structures C1 to C3 of the Comparative Examples. The results are shown in Table 1.

[0106] (1)Catalytic activity The catalytic activity was evaluated under the following conditions. First, 70 mg of the catalyst structure was loaded into an atmospheric pressure flow reactor, and the FT synthesis reaction was carried out while supplying hydrogen (8 ml / min) and carbon monoxide (4 ml / min) and heating at 100 to 700°C and 0.1 MPa for 1 hour. A single microreactor (Frontier Labs, Rx-3050SR) was used as the atmospheric pressure flow reactor.

[0107] After the reaction was completed, the recovered product gas and liquid were analyzed for their components by gas chromatography mass spectrometry (GC / MS). The product gas was analyzed using a TRACE 1310GC (manufactured by Thermo Fisher Scientific, Inc., detector: thermal conductivity detector).

[0108] Based on the results of the above analysis, the conversion rate of the substrate gas (CO) at 250°C was calculated. When the conversion rate of the substrate gas was 9% or more, the catalytic activity in the FT synthesis reaction was judged to be good and was marked with "○", when it was 3% or more but less than 9%, the catalytic activity was judged to be not good but at an acceptable level (passable) and was marked with "△", and when it was less than 3%, the catalytic activity was judged to be poor (unacceptable) and was marked with "×".

[0109] As is clear from Table 1, the catalyst structures (Examples 1 to 4), in which it was confirmed by cross-sectional observation that the catalytic substance was retained inside the support (skeleton), were found to exhibit superior catalytic activity in the FT synthesis reaction compared to a structure (Comparative Example 1) composed solely of the support (skeleton) and a catalyst structure (Comparative Example 2) in which the catalytic substance was simply attached to the outer surface of the support (skeleton).

[0110] Furthermore, it was found that the catalyst structures (Examples 1 to 4) in which the metal element (M) content of the metal fine particles was confirmed to be greater than 2.5 mass% in the above evaluation [D] exhibited superior catalytic activity in the FT synthesis reaction compared to the catalyst structure (Comparative Example 3) in which the metal element (M) content of the metal oxide fine particles was as low as 1.3 mass%. It was also found that when the metal element (M) content of the metal oxide fine particles was 2.6 to 6.9 mass%, which is greater than 2.5 mass%, the catalytic activity in the FT synthesis reaction tended to be improved.

[0111] [Table 1] [Explanation of symbols]

[0112] 1 Functional structure 10 Carrier (or skeleton) 10a outer surface 11 Passage 11a hole 12 Expanded diameter part 20 Functional substances 30 Functional substances D C Average particle size D F Average inner diameter D E Inner diameter

Claims

[Claim 1] a calcination step of calcining a precursor material (B) obtained by impregnating a precursor material (A) with a metal-containing solution to obtain a porous support composed of a zeolite-type compound; a hydrothermal treatment step of adding a structure-directing agent to a precursor material (C) obtained by calcining the precursor material (B) in the presence of a film composed of silica particles, and then subjecting the resulting precursor material (C) to hydrothermal treatment; and a method for producing a functional structure, the method comprising: adjusting an amount of the metal-containing solution to be added to the precursor material (A) so that the ratio of silicon (Si) constituting the precursor material (A) to the metal element (M) contained in the metal-containing solution to be added to the precursor material (A) (atomic number ratio Si / M) is 10 to 1000.

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