Methanol synthesis catalyst and method for producing methanol synthesis catalyst

Abstract

The present invention relates to a methanol synthesis catalyst which has a material represented by general formula (1): Mo2-xAxN. In general formula (1), A is at least one metal selected from among palladium, cobalt, nickel and rhodium, and 0.02<x<2.

Description

methanol synthesis catalyst and method for producing methanol synthesis catalyst

[0001] This invention relates to a methanol synthesis catalyst and a method for producing a methanol synthesis catalyst. This application claims priority under Japanese Patent Application No. 2024-194978, filed in Japan on November 7, 2024, the contents of which are incorporated herein by reference.

[0002] From the perspective of reducing carbon dioxide emissions, the synthesis reaction of methanol using carbon dioxide as a raw material is attracting attention. In this reaction, methanol can be synthesized using carbon dioxide and hydrogen as raw materials according to the following reaction equation: CO ２ +3H ２ →CH ３ OH + H ２ Currently, Cu-ZnO catalysts are used as catalysts for methanol synthesis reactions like this.

[0003] H. Sugiyama et. al. , "Room-Temperature CO2 Hydrogenation to Methanol over Air-Stable hcp-PdMo Intermetallic Catalyst," J. American Chem. Society, 2023, 145, 17, 9410-9416

[0004] The aforementioned Cu-ZnO catalysts have the problem of low activity at low temperatures. For this reason, Cu-ZnO catalysts must be used in high-temperature environments (e.g., 250°C to 300°C).

[0005] On the other hand, the methanol synthesis reaction described above is an exothermic reaction, and the methanol yield tends to decrease at high temperatures. Therefore, there is a problem in that it is difficult to sufficiently increase the methanol yield in the operating environment of conventional Cu-ZnO catalysts.

[0006] To address these issues, research and development on methanol synthesis at lower temperatures has been actively pursued in recent years. For example, Non-Patent Document 1 reports that PdMo intermetallic compounds can exhibit significantly higher methanol yields even at low temperatures.

[0007] However, even with the catalyst described in Non-Patent Document 1, the methanol yield at low temperatures is still not sufficient, and there is still a need for methanol synthesis catalysts that exhibit high activity at low temperatures.

[0008] This invention has been made in view of the above background, and aims to provide a methanol synthesis catalyst that can exhibit a significantly higher methanol yield even in low-temperature ranges compared to conventional methods. Furthermore, this invention aims to provide a method for producing such a methanol synthesis catalyst.

[0009] In this invention, a methanol synthesis catalyst is provided, wherein the following general formula (1) Mo ２－ｘ A ｘ A methanol synthesis catalyst is provided, comprising a material represented by N(1), wherein in the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2.

[0010] Furthermore, the present invention provides a method for producing a methanol synthesis catalyst, comprising: (I) dissolving a molybdenum compound and a second metal compound in a solvent to prepare a raw material solution; (II) drying the raw material solution to prepare a precipitate; and (III) nitriding the precipitate, wherein the second metal compound is at least one selected from palladium compounds, cobalt compounds, nickel compounds, and rhodium compounds, and the methanol synthesis catalyst is given by the following general formula (1) Mo ２－ｘ A ｘ A method for producing a methanol synthesis catalyst is provided, comprising a material represented by N (1), wherein in the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2.

[0011] The present invention provides a methanol synthesis catalyst that can exhibit a significantly higher methanol yield even at low temperatures compared to conventional methods. Furthermore, the present invention provides a method for producing such a methanol synthesis catalyst.

[0012] It is a diagram schematically showing the flow of a method for manufacturing a methanol synthesis catalyst according to an embodiment of the present invention. It is a diagram showing the X-ray diffraction analysis result of a methanol synthesis catalyst according to an embodiment of the present invention.

[0013] Hereinafter, an embodiment of the present invention will be described.

[0014] The methanol synthesis catalyst of the present embodiment has a material represented by the following general formula (1). Mo ２－ｘ A ｘ N (1) In the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2.

[0015] As described above, the Cu-ZnO-based catalyst has low activity at low temperatures and must be used in a high-temperature environment. However, the methanol synthesis reaction is an exothermic reaction, and there is a problem that it is difficult to sufficiently increase the methanol yield on the high-temperature side.

[0016] Also, in the PdMo intermetallic compound catalyst described in Non-Patent Document 1, the methanol yield in the low-temperature range is still not sufficient.

[0017] In contrast, the methanol synthesis catalyst of the present embodiment can exhibit a significantly higher methanol yield in the low-temperature range than in the past.

[0018] (Methanol synthesis catalyst) Hereinafter, the methanol synthesis catalyst of the present embodiment will be described in more detail.

[0019] (Composition) As described above, the methanol synthesis catalyst according to the present embodiment (hereinafter referred to as the "first catalyst") includes a material represented by the general formula (1) (hereinafter referred to as a "molybdenum nitride-based material"). Mo ２－ｘ A ｘ N (1) For example, the first catalyst may be composed of a molybdenum nitride-based material.

[0020] In the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2. The composition of the molybdenum nitride-based material can be confirmed using an inductively coupled plasma optical emission spectrometer. Specifically, the composition can be confirmed by dissolving the molybdenum nitride-based material in a solvent that does not contain Mo, A, and N, and subjecting the resulting solution to inductively coupled plasma optical emission spectrometry.

[0021] For example, when A is palladium, the molybdenum nitride-based material is Mo ２－ｘ Pd ｘ represented by N. Note that A may be only one type or two or more types. When there are two or more types, the total of A satisfies 0.02 < x < 2.

[0022] x is greater than 0.02. Also, x is preferably 1.0 or less, more preferably 0.5 or less, and even more preferably 0.1 or less. It is preferable that x is greater than 0.02 and 1.0 or less, more preferably greater than 0.02 and 0.5 or less, even more preferably greater than 0.02 and 0.1 or less, particularly preferably 0.03 to 0.1, and most preferably 0.03 to 0.06. When x exceeds (or is equal to or greater than) the above lower limit value, the methanol yield is likely to improve.

[0023] The molybdenum nitride-based material preferably has a structure in which A is doped at the Mo site of molybdenum nitride (Mo ２ N). That is, the molybdenum nitride-based material preferably has the same crystal structure as molybdenum nitride (Mo ２ N). The crystal structure of the molybdenum nitride-based material can be identified from the powder X-ray diffraction pattern obtained by powder X-ray diffraction measurement. Powder X-ray diffraction measurement is performed using a powder X-ray diffractometer. Specifically, the molybdenum nitride-based material is filled on a dedicated substrate, and measurement is performed using a Cu-Kα ray source to obtain a powder X-ray diffraction pattern.

[0024] (Form) The form of the first catalyst is not particularly limited. The first catalyst may be provided in the form of a powder, a film, or a bulk.

[0025] Furthermore, the first catalyst may consist solely of a molybdenum nitride-based material, or it may be provided in a state where the molybdenum nitride-based material is supported on a carrier. In this case, the shape of the carrier is not particularly limited, and the carrier may be in the form of a plate or particulate matter.

[0026] For example, if the carrier is in the form of a plate, the first catalyst may be in the form of a layer or powder and be provided supported on at least one main surface of the carrier.

[0027] When the carrier is in particle form, the molybdenum nitride-based material may be supported on the surface of the carrier particles. In this case, the content of the molybdenum nitride-based material relative to the total mass of the carrier particles and the molybdenum nitride-based material (i.e., the total mass of the methanol synthesis catalyst) may be 0.5% by mass or more and 10% by mass or less.

[0028] Furthermore, when the support is in plate form, the material of such a support is not particularly limited. On the other hand, when the support is in particle form, inorganic oxide support is an example of such a support. Examples of inorganic oxide support are silicon oxide, aluminum oxide, titanium oxide, boron oxide, magnesium oxide, zirconium oxide, etc. Among these, silicon oxide is preferred, and SiO ２ Silicon oxides such as those listed above are more preferable. As will be described later, when silicon oxide is used as the support, the first catalyst can exhibit a higher methanol yield. The support may be used alone or in combination of two or more types.

[0029] (Method for producing methanol synthesis catalyst) Next, with reference to Figure 1, an example of a method for producing the methanol synthesis catalyst of this embodiment will be described.

[0030] Figure 1 schematically shows the flow of the method for producing the methanol synthesis catalyst of this embodiment (hereinafter referred to as the "first method").

[0031] As shown in Figure 1, the first method comprises (I) a step of preparing a raw material solution by dissolving a molybdenum compound and a second metal compound in a solvent (step S110), (II) a step of preparing a precipitate by drying the raw material solution (step S120), and (III) a step of nitriding the precipitate (step S130).

[0032] The following describes each step.

[0033] In the following description, when A in the general formula (1) of the molybdenum nitride-based material contained in the methanol synthesis catalyst is palladium, that is, when the general formula of the molybdenum nitride-based material contained in the first catalyst is Mo ２－ｘ Pd ｘ The first method will be explained using the case of N (2) as an example. Therefore, the aforementioned "second metal compound" is a palladium compound.

[0034] However, the molybdenum nitride-based materials produced by the first method are not limited to these. That is, by using at least one of a cobalt compound, a nickel compound, and a rhodium compound in place of, or in addition to, the "palladium compound" described later in the first method, all molybdenum nitride-based materials represented by the above-mentioned general formula (1) can be produced.

[0035] (Step S110) First, the molybdenum compound and the palladium compound are dissolved in a solvent to prepare the raw material solution.

[0036] The molybdenum compound is selected from, for example, ammonium heptamolybdate and molybdenum bis(acetylacetonate) oxide. The palladium compound is selected from, for example, palladium acetate and palladium nitrate.

[0037] The concentration of the molybdenum compound in the raw material solution is, for example, in the range of 0.01% to 20% by mass. Similarly, the concentration of the palladium compound in the raw material solution is, for example, in the range of 0.01% to 20% by mass.

[0038] The solvent may be water or an aqueous solution. If the solvent is an aqueous solution, the aqueous solution may contain an acid. Examples of such acids include nitric acid, citric acid, and malic acid.

[0039] When dissolving molybdenum and palladium compounds, the solvent may be heated. The upper limit of the heating temperature is, for example, 80°C or lower.

[0040] Furthermore, a carrier may be added to the raw material solution. The carrier is preferably added in the form of particles.

[0041] The carrier may be composed of, for example, silicon dioxide. The average particle size of the carrier is, for example, in the range of 0.01 μm to 100 μm. The average particle size of the carrier can be measured by laser diffraction scattering. Specifically, a laser diffraction scattering particle size distribution analyzer is used to obtain a volume-based cumulative particle size distribution curve of the carrier. In the obtained cumulative particle size distribution curve, the value of the particle size at 50% accumulation from the fine particle side is taken as the average particle size.

[0042] (Step S120) Next, the raw material solution is dried to completely remove the solvent. The drying process may be carried out at room temperature or in a heated environment. If heated, the processing temperature is preferably in the range of 100°C to 200°C.

[0043] This allows us to obtain precipitates from the raw material solution.

[0044] (Step S130) Next, the obtained precipitate is subjected to nitriding treatment.

[0045] Furthermore, a pre-oxidation treatment may be performed on the precipitate before the nitriding treatment. By performing the pre-oxidation treatment, an oxide precursor containing molybdenum and palladium can be obtained as an intermediate product.

[0046] Nitriding is carried out, for example, by heating the precipitate in an atmosphere containing ammonia. The heating temperature is, for example, in the range of 600°C to 800°C.

[0047] After step S130, the general formula is Mo ２－ｘ Pd ｘ A Mo-Pd-N material represented by N(2) can be obtained. Here, 0.02 < x < 2. In particular, x is preferably 1.0 or less, more preferably 0.5 or less, and even more preferably 0.1 or less. x is preferably greater than 0.02 and 1.0 or less, more preferably greater than 0.02 and 0.5 or less, even more preferably greater than 0.02 and 0.1 or less, particularly preferably 0.03 to 0.1, and most preferably 0.03 to 0.06.

[0048] Furthermore, if carrier particles are added to the raw material solution in step S110 described above, a Mo-Pd-N based material supported on the surface of the carrier particles can be obtained.

[0049] The method for producing the methanol synthesis catalyst of this embodiment by the first method has been described above, using the Mo-Pd-N material represented by equation (2) as an example.

[0050] However, in the first method, by changing "palladium compound" to a cobalt compound, nickel compound, and rhodium compound, Mo ２－ｘ Co ｘ N-series, Mo ２－ｘ Ni ｘ N-series, Mo ２－ｘ Rh ｘ It is obvious to those skilled in the art that methanol synthesis catalysts containing molybdenum nitride-based materials such as N-based materials can be manufactured.

[0051] The following describes embodiments of the present invention. In the following description, Examples 1 to 6 are examples, and Examples 11 to 12 are comparative examples.

[0052] (Example 1) A methanol synthesis catalyst containing Mo-Pd-N material was produced by the following method.

[0053] First, a mixed solution was prepared by placing 0.834 g of ammonium heptamolybdate tetrahydrate, 0.0232 g of palladium acetate, 1.9 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. The mixed solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and palladium salt.

[0054] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0055] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and palladium.

[0056] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0057] This yielded a powder (hereinafter referred to as "powder 1").

[0058] Figure 2 shows the results of the X-ray diffraction analysis of powder 1.

[0059] As shown in Figure 2, powder 1 is composed of Mo ２ It was found to contain N-type materials.

[0060] Here, the X-ray diffraction results do not show any peaks for the palladium-based composition added as a raw material, therefore, palladium is Mo ２ It is thought to be doped into N-based materials. Furthermore, the amount of palladium contained in the raw material was 0.02 (molar ratio) relative to the total amount of molybdenum and palladium, so palladium is Mo １．９６ Pd ０．０４ As N, Mo ２ It is expected to be contained within N-type materials.

[0061] Thus, powder 1 is Mo １．９６ Pd ０．０４ It was inferred that it contained N.

[0062] (Example 2) A methanol synthesis catalyst containing Mo-Pd-N material was produced by the following method.

[0063] A solution was prepared by placing 0.083 g of ammonium heptamolybdate tetrahydrate, 0.0023 g of palladium acetate, 0.19 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. This solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and palladium salt.

[0064] Subsequently, 0.45 g of crystalline silica particles (average particle size 100 μm) was added to this solution to prepare a mixed solution.

[0065] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0066] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and palladium.

[0067] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0068] This yielded a powder (hereinafter referred to as "powder 2").

[0069] Microscopic observation revealed that in powder 2, Mo-Pd-N based material was supported on the surface of the silica particles. The content of Mo-Pd-N based material relative to the total mass of silica particles and Mo-Pd-N based material (i.e., the total mass of methanol synthesis catalyst) was 10% by mass.

[0070] Furthermore, based on the results of X-ray diffraction analysis, etc., powder 2 is Mo １．９６ Pd ０．０４ It was inferred that it contained N.

[0071] (Example 3) A methanol synthesis catalyst containing Mo-Pd-N material was produced by the following method.

[0072] A solution was prepared by placing 0.0083 g of hexaammonium heptamolybdate tetrahydrate, 0.0002 g of palladium acetate, 0.02 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. This solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and palladium salt.

[0073] Subsequently, 1 g of crystalline silica (average particle size 100 μm) was added to this solution to prepare a mixed solution.

[0074] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0075] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and palladium.

[0076] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0077] This yielded a powder (hereinafter referred to as "powder 3").

[0078] Microscopic observation revealed that in powder 3, Mo-Pd-N based material was supported on the surface of the silica particles. The content of Mo-Pd-N based material relative to the total mass of silica particles and Mo-Pd-N based material (i.e., the total mass of methanol synthesis catalyst) was 0.5% by mass.

[0079] Furthermore, based on the results of X-ray diffraction analysis, etc., powder 3 is Mo １．９６ Pd ０．０４ It was inferred that it contained N.

[0080] (Example 11) A methanol synthesis catalyst containing Mo-Pd material was produced by the following method.

[0081] First, a mixed solution was prepared by placing 0.834 g of hexaammonium heptamolybdate tetrahydrate, 1.1603 g of palladium acetate, 3.8 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. The mixed solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and palladium salt.

[0082] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0083] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and palladium.

[0084] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0085] This yielded a powder (hereinafter referred to as "powder 11").

[0086] X-ray diffraction analysis revealed that powder 11 contains hcp-type PdMo. In other words, powder 11 does not contain nitrogen atoms.

[0087] (Example 12) A methanol synthesis catalyst containing Mo-Pd-N material was produced by the following method.

[0088] First, a mixed solution was prepared by placing 0.834 g of hexaammonium heptamolybdate tetrahydrate, 0.0116 g of palladium acetate, 1.9 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. The mixed solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and palladium salt.

[0089] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0090] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and palladium.

[0091] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0092] This yielded a powder (hereinafter referred to as "powder 12").

[0093] Based on the results of X-ray diffraction analysis, etc., powder 12 is composed of Mo １．９８ Pd ０．０２ It was inferred that it contained N.

[0094] (Example 4) A methanol synthesis catalyst containing Mo-Co-N material was produced by the following method.

[0095] First, a mixed solution was prepared by placing 0.834 g of ammonium heptamolybdate tetrahydrate, 0.0301 g of cobalt nitrate hexahydrate, 1.9 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. Then, the mixed solution was stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and cobalt salt.

[0096] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0097] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and cobalt.

[0098] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0099] This yielded a powder (hereinafter referred to as "powder 4").

[0100] Based on the results of X-ray diffraction analysis, etc., powder 4 is composed of Mo １．９６ Co ０．０４ It was inferred that it contained N.

[0101] (Example 5) A methanol synthesis catalyst containing a Mo-Ni-N material was produced by the following method.

[0102] First, a mixed solution was prepared by placing 0.834 g of ammonium heptamolybdate tetrahydrate, 0.0300 g of nickel nitrate hexahydrate, 1.9 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. The mixed solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and nickel salt.

[0103] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0104] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This formed an oxide precursor containing molybdenum and nickel.

[0105] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0106] This yielded a powder (hereinafter referred to as "powder 5").

[0107] Based on the results of X-ray diffraction analysis, etc., powder 5 is composed of Mo １．９６ Ni ０．０４ It was inferred that it contained N.

[0108] (Example 6) A methanol synthesis catalyst containing Mo-Rh-N material was produced by the following method.

[0109] First, a mixed solution was prepared by placing 0.834 g of ammonium heptamolybdate tetrahydrate, 0.0299 g of rhodium nitrate, 1.9 g of anhydrous citric acid, 5 mL of 61% by mass concentrated nitric acid, and 45 mL of pure water into a 300 mL beaker. The mixed solution was then stirred at 80°C for 1 hour to completely dissolve the molybdenum salt and rhodium salt.

[0110] Next, the mixed solution was held at 200°C for 1 hour to completely remove the water and obtain a precipitate.

[0111] Subsequently, the precipitate in the beaker was transferred to an alumina crucible, and the alumina crucible was heated in air at 500°C for 2 hours. This resulted in the formation of an oxide precursor containing molybdenum and rhodium.

[0112] Next, this precursor was placed in a tubular furnace and heated at 750°C for 12 hours in an ammonia gas stream at a flow rate of 10 mL / min.

[0113] This yielded a powder (hereinafter referred to as "powder 6").

[0114] Based on the results of X-ray diffraction analysis, etc., powder 6 is composed of Mo １．９６ Rh ０．０４ It was inferred that it contained N.

[0115] Table 1 below summarizes the composition of each powder. In Table 1, "Catalyst content relative to the carrier" refers to the content of the Mo-Pd-N material relative to the total mass of silica particles and Mo-Pd-N material (i.e., the total mass of methanol synthesis catalyst).

[0116]

[0117] (Evaluation) Methanol synthesis tests were conducted using each powder.

[0118] The test was conducted as follows:

[0119] First, 100 mg of each powder was weighed out and packed into a quartz glass tube.

[0120] Subsequently, hydrogen gas was circulated through the quartz glass tube at a flow rate of 30 mL / min, and the quartz glass tube was heated at 300°C for 2 hours, then slowly cooled to activate the powder.

[0121] Next, the quartz glass tube was heated to a predetermined test temperature, and while maintaining this temperature, a mixture of hydrogen gas (30 mL / min), carbon dioxide gas (10 mL / min), and argon gas (10 mL / min) was circulated through the quartz glass tube.

[0122] The gases generated over two hours from the start of the reaction were collected and analyzed using gas chromatography (Agilent 7890A).

[0123] The test temperature was set at 160°C or 200°C.

[0124] Table 2 below summarizes the test results obtained for each powder.

[0125]

[0126] In Table 2, "methanol production" was calculated by dividing the total amount of methanol measured by the amount of catalyst (excluding the support) and the reaction time.

[0127] These test results confirmed that powders 1 to 6 yielded significantly higher methanol yields compared to powders 11 and 12 at both test temperatures of 160°C and 200°C.

[0128] (Aspects of the present invention) The present invention has the following aspects.

[0129] (Aspect 1) A methanol synthesis catalyst, wherein the following general formula (1) Mo ２－ｘ A ｘ A methanol synthesis catalyst having a material represented by N(1), wherein in the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2.

[0130] (Aspect 2) The methanol synthesis catalyst according to aspect 1, wherein A is palladium.

[0131] (Aspect 3) The methanol synthesis catalyst according to aspect 1 or 2, wherein x is greater than 0.02 and less than or equal to 1.0.

[0132] (Aspect 4) The methanol synthesis catalyst according to any one of aspects 1 to 3, wherein the methanol synthesis catalyst is supported on the surface of carrier particles.

[0133] (Aspect 5) The methanol synthesis catalyst according to aspect 4, wherein the carrier particles are composed of silicon dioxide.

[0134] (Aspect 6) The methanol synthesis catalyst according to aspect 4 or 5, wherein the content of the material relative to the total mass of the methanol synthesis catalyst is 0.5% by mass or more and 10% by mass or less.

[0135] (Aspect 7) A method for producing a methanol synthesis catalyst, comprising: (I) dissolving a molybdenum compound and a second metal compound in a solvent to prepare a raw material solution, wherein the second metal compound is at least one selected from a palladium compound, a cobalt compound, a nickel compound and a rhodium compound; (II) drying the raw material solution to prepare a precipitate; and (III) nitriding the precipitate, wherein after (III), the general formula is Mo ２－ｘ A ｘ A methanol synthesis catalyst represented by N(1) is obtained, where A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2, by a method.

[0136] (Aspect 8) The method according to aspect 7, wherein the molybdenum compound is ammonium heptamolybdate or molybdenum bis(acetylacetonate) oxide.

[0137] (Aspect 9) The method according to aspect 7 or 8, wherein the second metal compound is palladium acetate or palladium nitrate.

[0138] (Aspect 10) The method according to any one of aspects 7 to 9, wherein the solvent is water or an aqueous solution.

[0139] (Aspect 11) The method according to any one of aspects 7 to 10, wherein in (III), the precipitate is treated in an ammonia-containing atmosphere at a temperature of 600°C to 800°C.

[0140] (Aspect 12) The method according to any one of aspects 7 to 11, wherein in (I), the raw material solution further comprises carrier particles, and after (III), a methanol synthesis catalyst supported on the carrier particles is obtained.

[0141] (Aspect 13) The method according to aspect 12, wherein the carrier particles are composed of silicon dioxide.

[0142] The methanol synthesis catalyst of the present invention is useful because it can exhibit a significantly higher methanol yield even at low temperatures compared to conventional catalysts.

Claims

1. A methanol synthesis catalyst, wherein the following general formula (1) Mo ２－ｘ A ｘ A methanol synthesis catalyst having a material represented by N(1), wherein in the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2.

2. The methanol synthesis catalyst according to claim 1, wherein A is palladium.

3. The methanol synthesis catalyst according to claim 2, wherein x is greater than 0.02 and less than or equal to 1.

0.

4. The methanol synthesis catalyst according to claim 1, wherein the material is supported on the surface of a carrier.

5. The methanol synthesis catalyst according to claim 4, wherein the carrier comprises silicon dioxide.

6. The methanol synthesis catalyst according to claim 4, wherein the content of the material relative to the total mass of the methanol synthesis catalyst is 0.5% by mass or more and 10% by mass or less.

7. A method for producing a methanol synthesis catalyst, comprising: (I) dissolving a molybdenum compound and a second metal compound in a solvent to prepare a raw material solution; (II) drying the raw material solution to prepare a precipitate; and (III) nitriding the precipitate, wherein the second metal compound is at least one selected from palladium compounds, cobalt compounds, nickel compounds and rhodium compounds, and the methanol synthesis catalyst is given by the following general formula (1) Mo ２－ｘ A ｘ A method for producing a methanol synthesis catalyst, comprising a material represented by N(1), wherein in the general formula (1), A is at least one metal selected from palladium, cobalt, nickel, and rhodium, and 0.02 < x < 2.

8. The method for producing a methanol synthesis catalyst according to claim 7, wherein the molybdenum compound is hexaammonium heptamolybdate or molybdenum bis(acetylacetonato) oxide.

9. The method for producing a methanol synthesis catalyst according to claim 7, wherein the second metal compound is palladium acetate or palladium nitrate.

10. The method for producing a methanol synthesis catalyst according to claim 7, wherein the solvent is water or an aqueous solution.

11. The method for producing a methanol synthesis catalyst according to claim 7, wherein, in (III), the precipitate is treated in an ammonia-containing atmosphere at a temperature of 600°C to 800°C.

12. The method for producing a methanol synthesis catalyst according to claim 7, wherein in (I) above, the raw material solution further comprises a carrier, and the methanol synthesis catalyst is a methanol synthesis catalyst in which the material is supported on the surface of the carrier.

13. The method according to claim 12, wherein the carrier comprises silicon dioxide.

Images