Plate-shaped catalyst for carbon dioxide storage and reduction and method for producing the same

Abstract

To provide a plate-shaped catalyst capable of more efficiently absorbing and reducing carbon dioxide, and a method for producing the same. [Solution] A plate-shaped catalyst comprising the following: (A) catalyst metal, (B) alkali metal oxide and / or alkaline earth metal oxide, (C) catalyst support, and (D) alloy substrate, A plate-shaped catalyst for carbon dioxide storage and reduction, comprising the catalyst metal and the powder of the catalyst support on which the alkali metal oxide and / or alkaline earth metal oxide are supported, coated onto an alloy substrate. (A) Catalyst metal: One or more metals selected from Ni, Fe, Co, Cr, Cu, Sn, Bi, Zn, Ru, In, Rh, Pt, Au, and Pd. (B) Alkali metal oxides and / or alkaline earth metal oxides: Oxides of one or more metals selected from Li, Na, K, Ca, Mg, Ba, and Sr (C) Catalyst support: Metal oxide-based catalyst support

Description

Technical Field

[0001] The present invention relates to a plate-shaped catalyst for carbon dioxide storage and reduction, and a method for producing the same.

Background Art

[0002] Technologies for reducing carbon dioxide (CO2) to methane or carbon monoxide (CO) have attracted attention from the perspective of reducing CO2 emissions to curb global warming in recent years. As such technologies, various carbon dioxide storage and reduction catalysts in which a substance that stores CO2 and a catalyst that reduces CO2 are supported on a catalyst carrier have been reported (Non-Patent Document 1, Patent Documents 1 and 2).

Prior Art Literature

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a plate-shaped catalyst capable of storing and reducing carbon dioxide more efficiently, and a method for producing the same.

Means for Solving the Problems

[0006] The inventors have discovered that a plate-shaped catalyst capable of more efficiently absorbing and reducing carbon dioxide can be obtained by uniformly coating an alloy substrate with a powder containing a CO2-absorbing substance and a CO2-reducing catalyst supported on a catalyst carrier.

[0007] In other words, the present invention provides the following [1] to [6]. [1] A plate-shaped catalyst comprising the following: (A) a catalyst metal, (B) an alkali metal oxide and / or an alkaline earth metal oxide, (C) a catalyst support, and (D) an alloy substrate, A plate-shaped catalyst for carbon dioxide storage and reduction, comprising the catalyst metal and the powder of the catalyst support on which the alkali metal oxide and / or alkaline earth metal oxide are supported, coated onto an alloy substrate. (A) Catalyst metal: One or more metals selected from Ni, Fe, Co, Cr, Cu, Sn, Bi, Zn, Ru, In, Rh, Pt, Au, and Pd. (B) Alkali metal oxides and / or alkaline earth metal oxides: Oxides of one or more metals selected from Li, Na, K, Ca, Mg, Ba, and Sr (C) Catalyst support: Metal oxide-based catalyst support [2] The plate-shaped catalyst according to [1], wherein the alkaline earth metal oxide is calcium oxide. [3] The plate-shaped catalyst according to [1] or [2], wherein the metal oxide catalyst support is one or more selected from silica, alumina, ceria, titania, zirconia, amorphous silica-alumina, and cordierite. A method for producing a plate-shaped catalyst as described in [4][1], (1) A step of preparing a catalyst support powder by supporting (A) a catalyst metal and (B) an alkali metal oxide and / or alkaline earth metal oxide on (C) a catalyst support, (2) A step of heat-treating the catalyst support powder in an air atmosphere, (3) A step of dispersing the heat-treated catalyst support powder in an organic solvent to prepare a slurry, (4) A step of coating an alloy substrate with the slurry. A method for producing plate-shaped catalysts. [5] A method for producing a plate-shaped catalyst according to [4], characterized in that the viscosity of the organic solvent is 5 cps or more and 100 cps or less, and the surface tension is 25 dyn / cm or more. [6] The method for producing a plate-shaped catalyst according to [4] or [5], characterized in that the organic solvent is one or more selected from glycols, glycol ethers, glycol acrylates and glycol methacrylates. [Effects of the Invention]

[0008] The plate-shaped catalyst of the present invention is uniformly coated on an alloy substrate with (A) a catalyst metal and (B) a catalyst support powder on which alkali metal oxides and / or alkaline earth metal oxides are supported, thereby enabling efficient absorption and reduction of carbon dioxide. [Modes for carrying out the invention]

[0009] Terms used herein shall be used in the sense commonly used in the art unless otherwise specified.

[0010] One aspect of the present invention is a plate-shaped catalyst comprising (A) a catalyst metal, (B) an alkali metal oxide and / or an alkaline earth metal oxide, (C) a catalyst support, and (D) an alloy substrate, This is a plate-shaped catalyst for carbon dioxide storage and reduction, comprising the catalyst metal and the powder of the catalyst support on which the alkali metal oxide and / or alkaline earth metal oxide are supported, coated onto an alloy substrate. (A) Catalyst metal: One or more metals selected from Ni, Fe, Co, Cr, Cu, Sn, Bi, Zn, Ru, In, Rh, Pt, Au, and Pd. (B) Alkali metal oxides and / or alkaline earth metal oxides: Oxides of one or more metals selected from Li, Na, K, Ca, Mg, and Ba. (C) Catalyst support: Metal oxide-based catalyst support

[0011] The (A) metal catalyst used in the plate-shaped catalyst of the present invention is a catalyst for carbon dioxide reduction, and is preferably one or more metals selected from Ni, Fe, Co, Cr, Cu, Sn, Bi, Zn, Ru, In, Rh, Pt, Au, and Pd. From the viewpoint of carbon dioxide reduction ability and economic efficiency, one or more metals selected from Ni, Fe, Cu, Cr, Sn, and Zn are more preferred, and one or more metals selected from Ni, Fe, and Cr are even more preferred.

[0012] The alkali metal oxide and / or alkaline earth metal oxide used in the plate-shaped catalyst of the present invention is a metal oxide for carbon dioxide storage, and includes oxides of one or more metals selected from Li, Na, K, Ca, Mg, Ba, and Sr. Specifically, examples include lithium oxide, sodium oxide, potassium oxide, calcium oxide, magnesium oxide, barium oxide, and strontium oxide, but sodium oxide (Na2O) and calcium oxide (CaO) are more preferred, and calcium oxide (CaO) is even more preferred. Sodium oxide (Na2O) and calcium oxide (CaO) may also be used in combination.

[0013] The catalyst support (C) used in the plate-shaped catalyst of the present invention is a support that carries (A) a metal catalyst and (B) an alkali metal oxide and / or alkaline earth metal oxide, and a metal oxide-based catalyst support is used. There are no particular restrictions on the metal oxide-based catalyst support as long as it is used as a catalyst support, and examples include silica, alumina, ceria, titania, zirconia, amorphous silica-alumina, and cordierite. Of these, one or more catalyst supports selected from silica, titania, alumina, and ceria are preferred, and one or more catalyst supports selected from titania, alumina, and ceria are more preferred. The catalyst support used in the present invention is a powder, and its particle size is not particularly limited, but is preferably 0.01 to 50 μm, and more preferably 0.1 to 20 μm. Further, these catalyst supports are preferably porous catalyst supports, and the average pore diameter thereof is preferably 3 to 50 nm, more preferably 5 to 20 nm. The pore volume of the porous support is preferably 0.3 to 1.5 cm 3 / g, more preferably 0.3 to 1.0 cm 3 / g. The average pore diameter and pore volume can be measured by a BET / BJH pore distribution measurement method.

[0014] The means for supporting the (A) metal catalyst and the (B) alkali metal oxide and / or alkaline earth metal oxide on the (C) catalyst support is not particularly limited. For example, an aqueous solution containing a predetermined amount of an alkaline earth metal salt and / or alkali metal salt is prepared, a predetermined amount of the (C) catalyst support on which the (A) metal catalyst is supported is added to this aqueous solution, followed by drying and calcination, whereby a catalyst support powder having the (B) alkaline earth metal oxide and / or alkali metal oxide and the (A) metal catalyst supported on the (C) catalyst support can be obtained. Alternatively, an aqueous solution containing a predetermined amount of an alkaline earth metal salt and / or alkali metal salt is prepared, a predetermined amount of the catalyst support is added to this aqueous solution, followed by drying and calcination to prepare a support having the alkaline earth metal oxide and / or alkali metal oxide supported on the catalyst support, and this support is added to an aqueous solution in which a predetermined amount of a metal catalyst salt is dissolved, followed by drying and calcination, whereby the catalyst support powder having the (B) alkaline earth metal oxide and / or alkali metal oxide and the (A) metal catalyst supported on the (C) catalyst support can also be obtained. Here, the alkali metal salt, alkaline earth metal salt, and metal catalyst salt used are not particularly limited, and examples thereof include halides such as chlorides and fluorides, carbonates, hydrogencarbonates, nitrates, acetates, sulfates, and hydrogensulfates. Among these, nitrates and halides are preferred.

[0015] The plate-shaped catalyst of the present invention is a plate-shaped catalyst for carbon dioxide occlusion and reduction, in which a (C) catalyst support powder supporting (A) a catalyst metal and (B) an alkali metal oxide and / or alkaline earth metal oxide is coated on an alloy substrate. (C) The amount of catalyst metal (A) supported on the catalyst support is preferably 0.1 to 40 wt%, and more preferably 1 to 20 wt%, from the viewpoint of carbon dioxide reduction performance. Furthermore, from the viewpoint of carbon dioxide storage performance, the amount of (B) alkali metal oxide and / or alkaline earth metal oxide supported on (C) catalyst support is preferably 0.1 to 40 wt% as metal, and more preferably 1 to 20 wt%.

[0016] The plate-shaped catalyst of the present invention is a plate-shaped catalyst for carbon dioxide absorption and reduction, wherein the catalyst support powder is coated on an alloy substrate. The alloy substrate used here only needs to have heat resistance that prevents cracking, peeling, or other deformations that would hinder contact with the catalyst components at the reaction temperature of carbon dioxide absorption and reduction, which is 200 to 800°C. Examples include austenitic stainless steel represented by SUS304 and SUS316, austenitic-ferritic stainless steel represented by SUS329J1 and SUS329J3L, ferritic stainless steel represented by SUS430 and SUS434, and martensitic stainless steel represented by SUS410 and SUS403. Of these, SUS304, SUS316, SUS430, and SUS410 are preferred from an economic standpoint. The amount of catalyst support powder coating the alloy substrate is determined to be 0.1 to 200 mg / cm² per unit area of ​​the alloy substrate, from the viewpoint of sufficiently transferring the heat absorbed and exothermic amounts of the catalyst support powder during the carbon dioxide storage and reduction reaction to the alloy substrate and leveling out rapid temperature changes of the catalyst. 2 Preferably, 1 to 100 mg / cm³ 2 This is preferable.

[0017] The plate-shaped catalyst of the present invention is obtained by coating an alloy substrate with the catalyst support powder, (1) A step of preparing a catalyst support powder by supporting (A) a catalyst metal and (B) an alkali metal oxide and / or alkaline earth metal oxide on (C) a catalyst support, (2) A step of heat-treating the catalyst support powder in an air atmosphere, (3) A step of dispersing the heat-treated catalyst support powder in an organic solvent to prepare a slurry, (4) The step of coating an alloy substrate with the slurry, A method for producing plate-shaped catalysts is preferred. Here, step (1) is carried out as described above.

[0018] Step (2) is a step of heat-treating the catalyst support powder in an air atmosphere. The heat treatment process can take place in an atmosphere where air is present, and normal atmospheric conditions are sufficient. The heat treatment should be performed by heating to 500-1000°C for 2-6 hours.

[0019] Step (3) is a step in which the heat-treated catalyst support powder is dispersed in an organic solvent to prepare a slurry. The organic solvent used here is preferably one with a viscosity of 5 cps to 100 cps and a surface tension of 25 dyn / cm to 100 dyn / cm, from the viewpoint of slurry stability and dispersibility of the catalyst support powder. Here, viscosity and surface tension are the viscosity and surface tension at 20°C. By using such an organic solvent, the catalyst support powder is uniformly coated onto the alloy substrate. More preferably, one or more selected from glycols, glycol ethers, glycol acrylates, and glycol methacrylates that are liquid at room temperature are preferred. Specifically, examples include glycols such as ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol, polypropylene glycol, and polybutylene glycol, as well as glycol ethers, glycol acrylates, and glycol methacrylates listed in the table below. Here, room temperature refers to a range of 5 to 35°C.

[0020] [Table 1]

[0021] The amount of catalyst support powder added to the organic solvent is preferably 0.1 to 200% by weight, and more preferably 10 to 150%. The slurry is preferably manufactured at room temperature.

[0022] Step (4) is the step of coating the alloy substrate with the slurry. The coating process involves applying the slurry onto the alloy substrate and then drying it. The application method may be by brushing or spraying. Drying can be done by natural drying or vacuum drying, or by heating to around 300°C.

[0023] Through the steps (1) to (4) described above, the catalyst support powder can be uniformly coated onto the alloy substrate. As a result, the resulting plate-shaped catalyst becomes more efficient at absorbing and reducing carbon dioxide. [Examples]

[0024] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0025] Example 1 4 g of calcium nitrate tetrahydrate and 2.4 g of iron nitrate nonahydrate were dissolved in 50 mL of distilled water. 9 g of γ-alumina powder (particle size: 2-3 μm) was added to the resulting solution, stirred with a stirrer for 10 minutes, and then evaporated to dryness. The recovered sample was heat-treated in an electric furnace at 600 °C for 10 hours in an air atmosphere. The heat-treated sample was crushed in an agate mortar to obtain a powder sample. 1 g of the powder sample was mixed and dispersed with 1 g of diethylene glycol to obtain a slurry sample. The slurry sample was dropped and coated onto a 25 mm × 25 mm, 2 mm thick alloy substrate (SUS304), and the slurry medium was dried in a dryer to obtain a plate-shaped catalyst. From the weight of the alloy substrate after drying, it was confirmed that 0.2 g of catalyst powder was coated. When the surface of the obtained plate-shaped catalyst was observed with a stereomicroscope, it was confirmed that the catalyst support powder was uniformly attached to the alloy substrate.

[0026] Example 2 When catalyst support powder was applied to an alloy substrate using diethylene glycol monobutyl ether as the solvent for obtaining the slurry and then dried, it was confirmed that the catalyst support powder was uniformly adhered to the alloy substrate. In addition, when catalyst support powder was applied to an alloy substrate using one or more of the glycols, glycol ethers, glycol acrylates, and glycol methacrylates listed in Table 1 and then dried, it was confirmed that the catalyst support powder was uniformly adhered to the alloy substrate.

[0027] Comparative Example 1 When water or ethanol was used instead of diethylene glycol as the solvent to obtain the slurry, and the catalyst support powder was coated onto an alloy substrate and dried, the adhesion of the catalyst support powder to the alloy substrate was not uniform.

[0028] The carbon dioxide storage and conversion characteristics were confirmed using the plate-shaped catalyst obtained in Example 1. The plate-shaped catalyst was placed in a quartz reaction tube, heated to 850°C under an argon atmosphere, and hydrogen reduction treatment was performed under a hydrogen flow condition of 2 L / min. Subsequently, carbon dioxide and hydrogen were flowed at 150 mL / min each. The flow rates of carbon dioxide and carbon monoxide were calculated from the gas meter and gas chromatograph measurements of the flowing gas 5 minutes after the start of flow, and the conversion efficiency from carbon dioxide to carbon monoxide was calculated to be 35.8%.

[0029] In Comparative Example 1, the conversion efficiency of the plate-shaped catalyst prepared as an ethanol slurry when reacted under the same conditions was less than 10%.

Claims

1. A plate-shaped catalyst comprising the following: (A) a catalyst metal, (B) an alkali metal oxide and / or an alkaline earth metal oxide, (C) a catalyst support, and (D) an alloy substrate, A plate-shaped catalyst for carbon dioxide storage and reduction, comprising the catalyst metal and the powder of the catalyst support on which the alkali metal oxide and / or alkaline earth metal oxide are supported, coated onto an alloy substrate. (A) Catalyst metal: One or more metals selected from Ni, Fe, Co, Cr, Cu, Sn, Bi, Zn, Ru, In, Rh, Pt, Au, and Pd. (B) Alkali metal oxides and / or alkaline earth metal oxides: Oxides of one or more metals selected from Li, Na, K, Ca, Mg, Ba, and Sr. (C) Catalyst support: Metal oxide-based catalyst support

2. The plate-shaped catalyst according to claim 1, wherein the alkaline earth metal oxide is calcium oxide.

3. The plate-shaped catalyst according to claim 1 or 2, wherein the metal oxide-based catalyst support is one or more selected from silica, alumina, ceria, titania, zirconia, amorphous silica-alumina, and cordierite.

4. A method for producing a plate-shaped catalyst according to claim 1, (1) A step of preparing a catalyst support powder by supporting (A) a catalyst metal and (B) an alkali metal oxide and / or alkaline earth metal oxide on (C) a catalyst support, (2) A step of heat-treating the catalyst support powder in an air atmosphere, (3) A step of dispersing the heat-treated catalyst support powder in an organic solvent to prepare a slurry, (4) A step of coating an alloy substrate with the slurry. A method for producing plate-shaped catalysts.

5. The method for producing a plate-shaped catalyst according to claim 4, characterized in that the viscosity of the organic solvent is 5 cps or more and 100 cps or less, and the surface tension is 25 dyn / cm or more.

6. The method for producing a plate-shaped catalyst according to claim 4 or 5, characterized in that the organic solvent is one or more selected from glycols, glycol ethers, glycol acrylates, and glycol methacrylates.

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