Intermetallic compound or intermetallic-compound-containing substance containing same, catalyst, method for producing methanol, method for producing carbon monoxide, and method for producing intermetallic compound or intermetallic-compound-containing substance containing same

Abstract

The present invention makes it possible to provide: an intermetallic compound that has exceptional long-time durability while exhibiting excellent catalytic activity at low temperature and exceptional methanol synthesis selectivity in methanol synthesis from CO2 or CO, or an intermetallic-compound-containing substance containing said intermetallic compound; a catalyst in which the same is used; a method for producing methanol; and a method for producing an intermetallic compound or an intermetallic-compound-containing substance containing said intermetallic compound. An intermetallic compound according to an embodiment includes a crystal lattice in which a first metal atom and a second metal atom are present at adjacent positions, and includes the first metal atom and the second metal atom. The first metal atom is Pd; the second metal atom is one or more selected from the group consisting of Zn, In, and Ga; in the X-ray diffraction spectrum before temperature rise desorption measurement, the position of the peak of the intermetallic compound is different from the position of the peak of the first metal atom and from the position of the peak of the second metal atom; and the BET specific surface area is 1 m2 / g or greater.

Description

Intermetallic compound or intermetallic compound-containing material containing the same, catalyst, method for producing methanol, method for producing carbon monoxide, and method for producing intermetallic compound or intermetallic compound-containing material containing the same

[0001] The present invention relates to an intermetallic compound or an intermetallic compound-containing material containing the same, a catalyst, a method for producing methanol, a method for producing carbon monoxide, and a method for producing an intermetallic compound or an intermetallic compound-containing material containing the same. This application claims priority based on Japanese Patent Application No. 2024-098313, filed on June 18, 2024, the contents of which are incorporated herein by reference.

[0002] CO, a greenhouse gas ２ Processes for synthesizing methanol, which can be used as an energy carrier, from CO have been developed worldwide. ２ Research has been conducted into the hydrogenation of methanol to synthesize methanol.

[0003] However, CO ２ The hydrogenation reaction from ethanol to methanol is exothermic, and it is thermodynamically unfavorable to carry out the reaction at high temperatures. Therefore, efforts are being made to develop catalysts that enable methanol synthesis at low temperatures.

[0004] In Non-Patent Document 1, CO ２ MoS enables methanol synthesis from ２ Nanosheets are disclosed.

[0005] J. Hu, L. Yu, J. Deng, Y. Wang, K. Cheng, C. Ma, Q. Zhang, W. Wen, S. Yu, Y. Pan, J. Yang, H. Ma, F. Qi, Y. Wang, Y. Zheng, M. Chen, R. Huang, S. Zhang, Z. Zhao, J. Mao, X. Meng, Q. Ji, G. Hou, X. Han, X. Bao, Y. Wang, D. Deng, Nat Catal 2021, 4, 242-250.

[0006] However, the catalyst of Non-Patent Document 1 was not necessarily fully satisfactory.

[0007] Under these circumstances, the inventors of the present application have made extensive efforts to develop a CO ２ The present invention was arrived at by discovering an intermetallic compound and an intermetallic compound-containing material containing the same that exhibits excellent long-term durability and good catalytic activity at low temperatures while exhibiting methanol synthesis selectivity in the synthesis of methanol from CO. That is, the present invention provides an intermetallic compound or an intermetallic compound-containing material containing the same that is excellent in catalytic performance, as well as a catalyst utilizing the same, a method for producing methanol, a method for producing carbon monoxide, and a method for producing an intermetallic compound or an intermetallic compound-containing material containing the same.

[0008] More specifically, the present invention proposes the following means: [1] An intermetallic compound containing a first metal atom and a second metal atom, comprising a crystal lattice in which the first metal atom and the second metal atom are present in adjacent positions, the first metal atom being Pd, the second metal atom being one or more atoms selected from the group consisting of Zn, In, and Ga, and having a BET specific surface area of ​​1 m ２ / g or more. [2] The intermetallic compound according to [1], wherein, in an X-ray diffraction spectrum before thermal desorption measurement, the position of a peak of the intermetallic compound is different from the position of a peak of the first metal atom alone and the position of a peak of the second metal atom alone. [3] The intermetallic compound according to [2], wherein the first metal atom is Pd and the second metal atom is Zn, at least a part of the crystal lattice has a body-centered cubic (bcc) crystal structure, and in an X-ray diffraction spectrum before thermal desorption measurement, the peak positions of the intermetallic compound, in terms of diffraction angle 2θ, are: a first peak between 40.5° and 41.5°, and a second peak between 43.5° and 44.5°. [4] The intermetallic compound according to [2], wherein the BET specific surface area is 15 m ２ / g or more. [5] The intermetallic compound according to [3], wherein the volume ratio of the body-centered cubic (bcc) crystal structure to the total volume of the intermetallic compound is 50% or more. [6] The intermetallic compound according to any one of [1] to [5], wherein the ratio (molar fraction) of the number of moles of the first metal atoms to the total number of moles of the first metal atoms and the second metal atoms contained in the intermetallic compound is 5 mol% or more and 95 mol% or less. [7] The intermetallic compound according to any one of [1] to [5], wherein the ratio (molar fraction) of the number of moles of the first metal atoms to the total number of moles of the first metal atoms and the second metal atoms contained in the intermetallic compound is 10 mol% or more and 90 mol% or less. [8] The intermetallic compound according to any one of [1] to [7], wherein the molar ratio of the first metal atom to the second metal atom is 30:70 to 70:30. [9] The intermetallic compound according to any one of [1] to [7], wherein the molar ratio of the first metal atom to the second metal atom is 40:60 to 65:35.

[10] The intermetallic compound according to any one of [1] to [7], wherein the molar ratio of the first metal atom to the second metal atom is 50:50 to 60:40.

[11] The intermetallic compound according to any one of [1] to

[10] , which contains a multicoordinating atom exhibiting multicoordination.

[12] The intermetallic compound according to

[11] , wherein the multicoordinating atom is one or more selected from the group consisting of N, O, C, and B.

[13] An intermetallic compound-containing material containing the intermetallic compound according to any one of [1] to

[12] and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom.

[14] A CO2-containing material containing the intermetallic compound according to any one of [1] to

[12] or the intermetallic compound-containing material according to

[13] . ２

[15] The catalyst for methanol synthesis according to

[14] , further comprising a support supporting the intermetallic compound or the intermetallic compound-containing material. ２ Catalyst for methanol synthesis from CO. ２Use of the intermetallic compound according to any one of [1] to

[12] or the intermetallic compound-containing material according to

[13] as a catalyst for methanol synthesis from a catalyst.

[17] A method for producing methanol, comprising contacting hydrogen and at least one of carbon monoxide and carbon dioxide with the intermetallic compound according to any one of [1] to

[11] or the intermetallic compound-containing material according to

[13] .

[18] A method for producing carbon monoxide, comprising contacting hydrogen and carbon dioxide with the intermetallic compound according to any one of [1] to

[12] or the intermetallic compound-containing material according to

[13] .

[19] A method for producing an intermetallic compound or an intermetallic compound-containing material containing the same, the intermetallic compound comprising a first metal atom and a second metal atom, wherein the first metal atom is Pd, and the second metal atom is at least one selected from the group consisting of Zn, In, and Ga, the method comprising: a preliminary step of mixing a first compound containing the first metal atom with a second compound containing the second metal atom in the presence of polyvinylpyrrolidone to obtain a mixture; a first step of dehydrating the mixture obtained in the preliminary step to obtain a dehydrated product; a second step of firing the dehydrated product obtained in the first step under air to obtain a fired product; and a second step of firing the fired product obtained in the second step with NH ３

[20] The production method according to

[19] , wherein in the first step, the first compound and the second compound are mixed in the presence of nitric acid.

[0009] According to the above aspect of the present invention, CO ２ Alternatively, the present invention can provide an intermetallic compound or an intermetallic compound-containing material containing the same, which exhibits methanol synthesis selectivity while being excellent in long-term durability and exhibits good catalytic activity at low temperatures in the synthesis of methanol from CO, a catalyst using the same, a method for producing methanol, a method for producing carbon monoxide, and a method for producing the intermetallic compound or the intermetallic compound-containing material containing the same.

[0010] 1 is a flowchart of a method for producing an intermetallic compound or an intermetallic compound-containing material containing the same according to the present embodiment.

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[0099] [ ｘ / ZnO, PdZnN of Example 9 ｘ 10 shows the X-ray diffraction spectra of PdZn of Example 10, PdZn alloy (ICSD No. 180143), and ZnO (ICSD No. 26170). This figure shows the relationship between the reaction temperature and the methanol synthesis rate for the catalysts of Examples 5, 9, and 10. This figure shows the relationship between the reaction temperature and the methanol synthesis rate for the 25 wt % PdZnN of Example 5. ｘ 11 shows the relationship between the selectivity to methanol in the catalyst and the reaction temperature in the case of Pd / ZnO (Example 7). ２ In ３ Alloy (ICSD No. 640231), In ２ O ３ 14 shows the X-ray diffraction spectra of the intermetallic compound-containing material of Example 12 and Pd in ​​the ICSD (Inorganic Crystal Structure Database). ２ 1 shows X-ray diffraction spectra of Ga alloy (ICSD No. 409939), GaN (ICSD No. 34476), and the intermetallic compound-containing material of Example 13. ２1 shows the X-ray diffraction spectrum of the intermetallic compound-containing material of Example 14 and the Pd alloy (ICSD No. 409939) of ICSD (Inorganic Crystal Structure Database). ２ 1 shows X-ray diffraction spectra of Ga alloy (ICSD No. 09939) and GaN (ICSD No. 34476). 1 shows the relationship between reaction temperature and methanol synthesis rate for the catalysts of Examples 12 and 13. 1 shows the relationship between reaction temperature and CO production rate for the catalysts of Examples 12 and 13. 1 shows the relationship between reaction temperature and methanol selectivity for the catalysts of Examples 12 and 13. 1 shows the relationship between intermetallic compound-containing material of Example 15 and Pd in ​​ICSD (Inorganic Crystal Structure Database). ５ Ga ３ 16 shows X-ray diffraction spectra of PdGa (ICSD No. 261111) and GaN (ICSD No. 34476) in the intermetallic compound-containing material of Example 16 and ICSD (Inorganic Crystal Structure Database). 17 shows X-ray diffraction spectra of PdGa (ICSD No. 261111) and GaN (ICSD No. 34476) in the intermetallic compound-containing material of Example 16. 18 shows X-ray diffraction spectra of PdGa (ICSD No. 261111) and GaN (ICSD No. 34476) in the intermetallic compound-containing material of Example 16. 19 ...

[0011] Hereinafter, an intermetallic compound or an intermetallic compound-containing material containing the same, a catalyst, a method for producing methanol, a method for producing carbon monoxide, and a method for producing an intermetallic compound or an intermetallic compound-containing material containing the same according to the embodiments will be described.

[0012] <Intermetallic Compound> The intermetallic compound according to this embodiment includes a first metal atom and a second metal atom, and includes a crystal lattice in which the first metal atom and the second metal atom are adjacent to each other, where the first metal atom is Pd and the second metal atom is one or more selected from the group consisting of Zn, In, and Ga. Here, the intermetallic compound is a compound composed of two or more metals, and is a compound of metals that forms an ordered lattice structure, unlike general alloys (e.g., a substance in which different elements are simply mixed and have an irregular lattice structure in which the different elements occupy crystal lattice sites in a disordered manner). In an X-ray diffraction spectrum before thermal desorption measurement, the peak position of the intermetallic compound is different from the peak position of the first metal atom alone and the peak positions of the second metal atom alone, and the BET specific surface area is 1 m ２ / g or more. The intermetallic compound according to this embodiment will be described below.

[0013] (Chemical Composition) The intermetallic compound according to this embodiment contains first and second metal atoms, which will be described later. The chemical composition of the intermetallic compound according to this embodiment will be described below.

[0014] "First Metal Atom" In the intermetallic compound according to this embodiment, the first metal atom is Pd. By using Pd as the first metal atom, the intermetallic compound according to this embodiment can obtain good conversion efficiency.

[0015] "Second Metal Atom" In the intermetallic compound according to this embodiment, the second metal atom is one or more selected from the group consisting of Zn, In, and Ga. When the first metal atom is Pd and the second metal atom is one or more selected from the group consisting of Zn, In, and Ga, the intermetallic compound according to this embodiment can be formed by CO ２ Alternatively, good conversion efficiency can be achieved in the synthesis of methanol from CO.

[0016] "Ratio of moles of first metal atoms to the total moles of first metal atoms and second metal atoms" The ratio (molar fraction) of the moles of first metal atoms to the total moles of first metal atoms and second metal atoms contained in the intermetallic compound according to this embodiment is preferably 5 mol% or more and 95 mol% or less. When there are two or more types of first metal atoms, the moles of the first metal atoms are the sum of the moles of those atoms. More preferably, the ratio (molar fraction) of the moles of first metal atoms is 10 mol% or more and 90 mol% or less. Even more preferably, the ratio (molar fraction) of the moles of first metal atoms is 10 mol% or more and 60 mol% or less. Incidentally, if the ratio exceeds 60 mol%, the ratio of first metal atoms and second metal atoms present at adjacent positions tends to decrease, so it is preferable that the ratio be 60 mol% or less. When the ratio (molar fraction) of the number of moles of the first metal atoms to the total number of moles of the first metal atoms and the second metal atoms contained in the intermetallic compound is 5 mol % or more and 95 mol % or less, the ratio of the first metal atoms and the second metal atoms existing at positions adjacent to each other increases, and CO ２ Alternatively, the conversion efficiency of the intermetallic compound can be improved in the synthesis of methanol from CO. When the intermetallic compound according to this embodiment contains atoms other than both the first metal atom and the second metal atom (for example, one or more types of multi-coordinate atoms), the ratio (molar fraction) of the number of moles of the other atoms to the total number of moles of the first metal atom and the second metal atom (i.e., 100 mol%) is preferably 30.0 mol% or less, and more preferably 20.0 mol% or less.

[0017] "Molar ratio of first metal atom to second metal atom" The molar ratio (molar ratio) of the first metal atom to the second metal atom in the intermetallic compound according to this embodiment is preferably 30:70 to 70:30. When the first metal atom is Pd and the second metal atom is Zn, the molar ratio of the first metal atom to the second metal atom is more preferably 40:60 to 65:35, and even more preferably 50:50 to 60:40. When the molar ratio of the first metal atom to the second metal atom in the intermetallic compound according to this embodiment is 30:70 to 70:30, the number of crystal lattices in which the first metal atom and the second metal atom are present at positions adjacent to each other increases, and the intermetallic compound has a CO ２ Alternatively, in the synthesis of methanol from CO, the conversion efficiency can be further improved.

[0018] "Multicoordinate atom exhibiting multicoordinate property" The intermetallic compound according to this embodiment may contain a multicoordinate atom exhibiting multicoordinate property. When the intermetallic compound according to this embodiment contains a multicoordinate atom exhibiting multicoordinate property, the stability of the intermetallic compound in terms of its crystal structure is improved. Here, a multicoordinate atom refers to an atom having two or more nearest neighbor atoms in the crystal. Examples of the multicoordinate atom include one or more selected from the group consisting of N (nitrogen), O (oxygen), C (carbon), and B (boron). N and O are preferred as the multicoordinate atom. N is particularly preferred as the multicoordinate atom because it further improves the stability of the intermetallic compound according to this embodiment in terms of its crystal structure.

[0019] When the intermetallic compound according to this embodiment contains a multicoordinate atom, distortion may occur in the crystal lattice. In the intermetallic compound according to this embodiment, distortion may occur in the crystal lattice as long as the first metal atom and the second metal atom are adjacent to each other. The total content of multicoordinate atoms relative to the total mass of the intermetallic compound according to this embodiment is not particularly limited as long as it does not eliminate the effects of the present invention. For example, when the first metal atom is Pd and the second metal atom is Zn, the total content may be, for example, 40 mol% or less, preferably 30 mol% or less, and more preferably 25 mol%. In this case, the molar ratio of the first metal atom to the second metal atom is 40:60 to 60:40, preferably 50:50. Furthermore, when the first metal atom is Pd and the second metal atom is Ga or In, the total content may be, for example, 30 mol% or less, preferably 15 mol% or less, and more preferably 10 mol% or less.

[0020] Since polycoordinate atoms may not be contained, the lower limit of the total content of polycoordinate atoms is 0 mass%. A more preferred total content of polycoordinate atoms is 0.1 mol% or more. When polycoordinate atoms are not contained, preferred examples include intermetallic compounds in which the second metal atom is In or Ga. On the other hand, when polycoordinate atoms are contained, preferred examples include intermetallic compounds in which the second metal atom is Zn.

[0021] When the multicoordinate atom is N, and the first metal atom is Pd and the second metal atom is Zn, the N content in the intermetallic compound can be, for example, 1 mol% to 40 mol%, preferably 5 mol% to 30 mol%, and more preferably 10 mol% to 25 mol%. In this case, the molar ratio of the first metal atom to the second metal atom is 40:60 to 60:40, preferably 50:50. When the first metal atom is Pd and the second metal atom is Zn, the N content in the intermetallic compound according to this embodiment is 1 mol% to 40 mol%, thereby further improving the stability of the intermetallic compound in terms of its crystal structure. Thus, when the first metal atom is Pd and the second metal atom is Zn, the N content in the intermetallic compound according to this embodiment is 1 mol% to 40 mol%, thereby further improving the stability of the intermetallic compound in terms of its crystal structure.

[0022] When the multicoordinating atom is N, and the first metal atom is Pd and the second metal atom is Ga or In, the N content in the intermetallic compound can be, for example, 1 mol % to 30 mol %, preferably 1 mol % to 15 mol %, and more preferably 1 mol % to 10 mol %. Thus, when the first metal atom is Pd and the second metal atom is Ga or In, if the N content in the intermetallic compound according to this embodiment is 1 mol % to 30 mol %, the stability of the intermetallic compound in terms of its crystal structure is further improved.

[0023] When the intermetallic compound is composed of one or more first metal atoms, one or more second metal atoms, and one or more multi-coordinate atoms, the intermetallic compound is ｘ B ｙ C ｚwhere A is a first metal atom, B is a second metal atom, and C in the formula is a polycoordinate atom, for example, 0.05≦x≦0.95, 0.05≦y≦0.95, and x+y=1.00. Z is 0≦z≦0.6, but when the polycoordinate atom is N, the first metal atom is Pd, and the second metal atom is Zn, for example, 0.1≦z≦0.6, preferably z≦0.5. On the other hand, when the coordinating atom is N, the first metal atom is Pd, and the second metal atom is Ga or In, for example, 0≦z≦0.4, preferably z≦0.3, more preferably z≦0.2, and even more preferably z≦0.1.

[0024] The ratio of the number of moles of the first metal atoms to the total number of moles of the first and second metal atoms contained in the intermetallic compound and the molar ratio of the first metal atoms to the second metal atoms in the intermetallic compound can be evaluated by analyzing the surface of a sample using an electron probe microanalyzer (EPMA) and determining the content ratio of the detected atoms using the ZAF method. Similarly, the presence or absence of polycoordinated atoms and the content of the polycoordinated atoms can be evaluated by analyzing the surface of a sample using an EPMA and determining the content ratio of the detected atoms using the ZAF method. Furthermore, if the intensities of the first and second peaks of the X-ray diffraction spectrum after thermal desorption measurement are the same as those before thermal desorption measurement, it can be evaluated that no polycoordinated atoms are present or that the content of the polycoordinated atoms is zero or a trace amount. On the other hand, if the intensities of the first and second peaks are decreased compared to before thermal desorption measurement, it can be evaluated that the polycoordinated atoms are present and the content of the polycoordinated atoms is an amount corresponding to the amount of decrease.

[0025] (X-ray diffraction spectrum) In the X-ray diffraction spectrum of the intermetallic compound according to this embodiment before thermal desorption measurement, if the position of the peak of the intermetallic compound is different from the position of the peak of the first metal atom alone (for example, 40.1°, face-centered cubic structure) and the position of the peak of the second metal atom alone (for example, 43.2°, hexagonal close-packed structure in the case of Zn), this indicates that the first metal atom and the second metal atom are CO ２ Or, since the arrangement promotes the hydrogenation reaction of CO, ２ Or, it improves the conversion efficiency in the synthesis of methanol from CO. If it can be confirmed that the characteristic peak positions of the above intermetallic compounds are different from the peak positions of the corresponding alloys, it can be determined whether they are simply alloys or intermetallic compounds.

[0026] Furthermore, the first metal atom is Pd, the second metal atom is Zn, at least a part of the crystal lattice has a body-centered cubic (bcc) crystal structure, and in the X-ray diffraction spectrum before thermal desorption measurement, the peak positions of the intermetallic compound have a first peak between 40.5° and 41.5° (i.e., the presence of a (111) plane in the body-centered cubic crystal structure) and a second peak between 43.5° and 44.5° (i.e., the presence of a (200) plane in the body-centered cubic crystal structure) as a diffraction angle 2θ. This indicates that the first metal atom and the second metal atom are CO ２ Or, since the arrangement promotes the hydrogenation reaction of CO, ２Or, it further improves the conversion efficiency in the synthesis of methanol from CO. Note that the characteristic peak positions of the intermetallic compound, namely the peak positions on the (111) plane and the (200) plane, are shifted to lower angles than the peak positions of the PdZn alloy (general alloy) used as a reference, which confirms that the constituent elements are present in a state of greater lattice expansion compared to PdZn (general alloy) (see, for example, FIG. 5). That is, when the first metal atom is Pd and the second metal atom is Zn, in the X-ray diffraction spectrum of the intermetallic compound of this embodiment before thermal desorption measurement, the peak positions of the intermetallic compound, as a diffraction angle 2θ, are preferably such that a first peak (i.e., the presence of a (111) plane in a body-centered cubic lattice crystal structure) is between 40.5° and 41.5° (i.e., the presence of a (200) plane in a body-centered cubic lattice crystal structure) is between 43.5° and 44.5°, and further, the first and second peaks are shifted to lower angles than the corresponding peak positions of the PdZn alloy (ICSD No. 180143) used as a reference. For example, the angle may be shifted to lower angles by 0.05° or more, by 0.1° or more, or by 0.2° or more.

[0027] Thus, in the X-ray diffraction spectrum of the intermetallic compound according to this embodiment before thermal desorption measurement, the positions of the first and second peaks are different from the positions of the peaks of the first and second metal atoms alone. Due to the difference in peak positions, the intermetallic compound according to this embodiment has a crystal structure and bonding pattern different from those of its constituent elements, the first and second metal atoms alone, and is therefore thought to be able to exhibit properties different from those of the two constituent elements. Furthermore, it is thought that such an intermetallic compound has a crystal structure in which the two constituent elements are bonded in a simple integer ratio and have a regularly arranged crystal structure. Incidentally, data from the Inorganic Crystal Structure Database (ICSD) can be used for the peaks of the first and second metal atoms alone.

[0028] In the X-ray diffraction spectrum of the intermetallic compound according to this embodiment after the thermal desorption measurement, the intensity of the first peak and the intensity of the second peak are equal to or decreased compared to before the thermal desorption measurement. That is, the intensity of the first peak is equal to or decreased after the thermal desorption measurement. Similarly, the intensity of the second peak is equal to or decreased after the thermal desorption measurement.

[0029] The X-ray diffraction spectrum of the intermetallic compound according to this embodiment before the thermal desorption measurement can be obtained by measuring a sample using, for example, an X-ray diffractometer (for example, a Bruker X-ray diffractometer D2 Phaser) with a CuKα X-ray source, a measurement angle range of 10° to 80°, a measurement temperature of room temperature (25°C), a scan speed of 0.2 seconds / step, and a scan step of 0.01°. The X-ray diffraction spectrum of the intermetallic compound according to this embodiment after the thermal desorption measurement can be obtained by measuring the sample after the thermal desorption measurement described below under the same conditions as the X-ray diffraction measurement conditions of the intermetallic compound according to this embodiment before the thermal desorption measurement.

[0030] When the intermetallic compound according to this embodiment is heated in an Ar atmosphere from room temperature (25°C) to 1000°C at a rate of 10°C / min and then held at 1000°C for 1 hour, the gas species desorbed during this process can be confirmed by analysis using a mass spectrometer attached to a catalyst analyzer (for example, BELCAT II manufactured by MicrotracBEL). An example of the intermetallic compound after temperature-programmed desorption measurement is an intermetallic compound that has been heated in an Ar atmosphere from room temperature (25°C) to 700°C at a rate of 10°C / min and then held at 700°C for 1 hour.

[0031] (Crystal lattice in which first metal atoms and second metal atoms are adjacent to each other) The intermetallic compound according to this embodiment includes a crystal lattice in which first metal atoms and second metal atoms are adjacent to each other. The presence of the first metal atoms and the second metal atoms adjacent to each other can increase the conversion efficiency of the intermetallic compound.

[0032] Confirmation that the intermetallic compound contains a crystal lattice in which a first metal atom and a second metal atom are adjacent to each other can be performed, for example, by the following method. First, the composition ratio of the intermetallic compound is analyzed using, for example, an electron probe microanalyzer (EPMA), and the content ratio (atomic %) of the detected atoms relative to the intermetallic compound is determined using the ZAF method. More specifically, for example, the EPMA analysis may be performed using a JEOL JXA-8530F. First, elemental mapping of the catalyst is performed, and then a mapping image is obtained. The composition ratio of the catalyst may be determined by analyzing the composition using the ZAF method for 50 (randomly selected) locations within the region where Pd and Zn are detected in the obtained mapping image, and the average value of the results may be used as the composition ratio. Similarly, X-ray diffraction (XRD) measurement of the intermetallic compound is performed to obtain an X-ray diffraction spectrum. By identifying the intermetallic compound from the atoms and composition ratios obtained by EPMA and the X-ray diffraction spectrum obtained from the XRD measurement using, for example, the Inorganic Crystal Structure Database (ICSD), it can be determined whether or not the intermetallic compound contains a crystal lattice in which a first metal atom and a second metal atom are located adjacent to each other.

[0033] In the intermetallic compound according to this embodiment, when the first metal atom is Pd and the second metal atom is Zn, it is preferable that at least a part of the crystal lattice in the intermetallic compound has a body-centered cubic (bcc) crystal structure. If at least a part of the crystal lattice in the intermetallic compound has a body-centered cubic (bcc) crystal structure, the intermetallic compound can be CO ２ Alternatively, in the synthesis of methanol from CO, the conversion efficiency can be further improved.

[0034] In the intermetallic compound according to this embodiment, it is preferable that the volume ratio of the crystal structure of the crystal lattice in which the first metal atom and the second metal atom are present at positions adjacent to each other is 50% or more relative to the total volume of the intermetallic compound. If the ratio of the crystal structure of such a crystal lattice is 50% or more, the intermetallic compound can be, for example, CO ２Alternatively, the conversion efficiency can be further improved in the synthesis of methanol from CO. The volume fraction of the crystal structure of the crystal lattice in which the first metal atom and the second metal atom are present at adjacent positions is preferably 60% or more, more preferably 80% or more. The upper limit of the volume fraction of the crystal structure of the crystal lattice in which the first metal atom and the second metal atom are present at adjacent positions is not particularly limited, but is, for example, 100%.

[0035] In the intermetallic compound according to this embodiment, when the first metal atom is Pd and the second metal atom is Zn, the volume ratio of the body-centered cubic (bcc) crystal structure to the total volume of the intermetallic compound is preferably 50% or more. If the ratio of the body-centered cubic (bcc) crystal structure is 50% or more, the intermetallic compound can be formed into a CO ２ Alternatively, the conversion efficiency can be further improved in the synthesis of methanol from CO. The volume fraction of the body-centered cubic (bcc) crystal structure is preferably 60% or more, more preferably 80% or more. The upper limit of the volume fraction of the body-centered cubic (bcc) crystal structure is not particularly limited, but is, for example, 100%.

[0036] Incidentally, in the intermetallic compound according to this embodiment, when the first metal atom is Pd and the second metal atom is In or Ga, the crystal structure will not correspond to a body-centered cubic (bcc) lattice, and therefore the volume ratio of the body-centered cubic (bcc) lattice crystal structure to the total volume of the intermetallic compound may be substantially 0%.

[0037] To confirm that at least a portion of the crystal lattice in the intermetallic compound is a body-centered cubic (bcc) lattice, the crystal lattice can be identified using the Inorganic Crystal Structure Database (ICSD) from the composition ratio and X-ray diffraction spectrum of the intermetallic compound measured by the above-mentioned method. The volume fraction occupied by the body-centered cubic (bcc) lattice can be determined by creating a calibration curve based on the XRD measurement results.

[0038] (Average particle size) The average particle size of the intermetallic compound or the substance containing an intermetallic compound according to this embodiment is 500 μm or less. More preferably, the average particle size of the intermetallic compound or the substance containing an intermetallic compound is 100 μm or less. By having an average particle size of 500 μm or less, CO ２ Alternatively, the conversion efficiency in methanol synthesis can be further improved because the contact area with CO can be increased. The intermetallic compound or the intermetallic compound-containing substance may have an average particle size of 1 μm or more.

[0039] The average particle size of the intermetallic compound or the substance containing an intermetallic compound is determined by observing the intermetallic compound or the substance containing an intermetallic compound with a field emission scanning electron microscope, selecting 50 intermetallic compounds or substances containing an intermetallic compound from the SEM image obtained, and measuring the maximum value between any two points on the outline of each intermetallic compound or substance containing an intermetallic compound. The average of the obtained values ​​is defined as the average particle size.

[0040] (BET Specific Surface Area) The BET specific surface area of ​​the intermetallic compound or intermetallic compound-containing material according to this embodiment is 1 m ２ / g or more. Preferably, 2m ２ / g or more, more preferably 15m ２ / g or more, more preferably 30m ２ / g or more. The BET specific surface area is 1 m ２ / g or more, ２ Since the contact area with the intermetallic compound can be increased, the conversion efficiency in methanol synthesis can be further improved. The BET specific surface area of ​​the intermetallic compound or the intermetallic compound-containing substance is 1000 m ２ / g or less.

[0041] The BET specific surface area of ​​the intermetallic compound or the substance containing the intermetallic compound can be obtained by measuring using a specific surface area / pore distribution measuring device (for example, BELSORP-mini II manufactured by Microtrac-Bell) with nitrogen (purity 99.99995%) as the adsorption gas and the adsorption temperature set to the liquid nitrogen temperature (-196°C).

[0042] <Intermetallic Compound-Containing Substance> The intermetallic compound-containing substance according to this embodiment may contain the intermetallic compound according to this embodiment and at least one of an oxide of at least one of a first metal atom and a second metal atom, and a nitride of at least one of the first metal atom and a second metal atom. The intermetallic compound-containing substance contains at least one of an oxide of at least one of a first metal atom and a second metal atom, and a nitride of at least one of a first metal atom and a second metal atom, which contributes to the stability of the crystal structure of the intermetallic compound in high-temperature regions, thereby improving the high-temperature resistance of a catalyst containing the intermetallic compound-containing substance. As a result, the intermetallic compound-containing substance exhibits excellent long-term durability while exhibiting methanol synthesis selectivity.

[0043] Examples of oxides of at least one of the first metal atom and the second metal atom include PdO, PdO ２ , ZnO, In ２ O, In ２ O ３ , Ga ２ O ３ Examples of nitrides of at least one of the first metal atom and the second metal atom include PdN ２ , Zn ３ N ２ , InN, GaN, etc.

[0044] To confirm that the sample contains at least one oxide of at least one of the first metal atoms and the second metal atoms, and at least one nitride of at least one of the first metal atoms and the second metal atoms, elemental mapping of the sample surface is performed using an EPMA. After elemental mapping, if N (nitrogen element) and the first metal atoms or the second metal atoms are detected in a predetermined ratio in the same region, it is determined that a nitride is present. After elemental mapping, if O (oxygen element) and the first metal atoms or the second metal atoms are detected in a predetermined ratio in the same region, it is determined that an oxide is present. The predetermined ratio is determined depending on the expected compound.

[0045] <Method for Producing an Intermetallic Compound or an Intermetallic Compound-Containing Material Containing the Intermetallic Compound> Next, a method for producing an intermetallic compound or an intermetallic compound-containing material containing the intermetallic compound according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a flowchart of a method for producing an intermetallic compound or an intermetallic compound-containing material containing the intermetallic compound according to this embodiment. The method for producing an intermetallic compound or an intermetallic compound-containing material containing the intermetallic compound according to this embodiment is a method for producing an intermetallic compound containing a first metal atom and a second metal atom, where the first metal atom is Pd and the second metal atom is one or more selected from the group consisting of Zn, In, and Ga. The method for producing an intermetallic compound according to this embodiment includes a pre-step S0 in which a first compound containing the first metal atom and a second compound containing the second metal atom are mixed to obtain a mixture, a first step S1 in which the mixture obtained in the pre-step S0 is dehydrated to obtain a dehydrated product, a second step S2 in which the dehydrated product obtained in the first step S1 is fired in the atmosphere to obtain a fired product, and a second step S3 in which the fired product obtained in the second step S2 is fired with NH ３ and a third step S3 of performing a heat treatment under reduced pressure. Each step will be described below.

[0046] (Pre-Step S0) In the pre-step S0, a first compound containing a first metal atom and a second compound containing a second metal atom are mixed to obtain a mixture.

[0047] (First Step S1) In the first step S1, the mixture obtained in the previous step S0 is dehydrated to obtain a dehydrated product.

[0048] (First Compound) The first compound is a compound containing a first metal atom. The first metal atom is Pd. The first compound is not particularly limited as long as it contains Pd and is soluble in a solvent. Examples of the first compound include palladium acetate (Pd(CH ３ COO) ２ ) etc.

[0049] (Second Compound) The second compound is a compound containing a second metal atom. The second metal atom is one or more selected from the group consisting of Zn, In, and Ga. The second compound is not particularly limited as long as it contains one or more selected from the group consisting of Zn, In, and Ga and is soluble in a solvent. Examples of the second compound include Zn(NO３ ) ２ ・6H ２ O, In(NO ３ ) ３ ・3H ２ O, Ga(NO ３ ) ３ ・xH ２ Examples include O.

[0050] (Combination ratio of first compound and second compound) The ratio (molar fraction) of the number of moles of the first compound to the total number of moles of the first compound and the second compound is preferably 5 mol% or more and 95 mol% or less. More preferably, the ratio (molar fraction) of the number of moles of the first compound is 10 mol% or more and 90 mol% or less. Even more preferably, the ratio (molar fraction) of the number of moles of the first compound is 10 mol% or more and 52 mol% or less. When the ratio (molar fraction) of the number of moles of the first compound to the total number of moles of the first compound and the second compound is 5 mol% or more and 95 mol% or less, the first metal atom and the second metal atom can be present at adjacent positions, and therefore, the intermetallic compound can be CO ２ Alternatively, in the synthesis of methanol from CO, it can have a good conversion efficiency.

[0051] In the first step S1, a first compound and a second compound are first mixed in the presence of polyvinylpyrrolidone to obtain a mixture. The method for mixing the first compound and the second compound is not particularly limited. The first compound and the second compound may be mixed, for example, by dissolving the first compound and the second compound in a 6% aqueous nitric acid solution. The solvent is not particularly limited as long as it can dissolve the first compound and the second compound, and organic solvents such as water and methanol may be used. The acid is also not particularly limited as long as it is soluble in the solvent used for mixing, and nitric acid, sulfuric acid, hydrochloric acid, etc. may be used. The amount of polyvinylpyrrolidone added is preferably at least twice the molar equivalent of the total number of moles of the first metal and the second metal contained in the first compound and the second compound. By adding polyvinylpyrrolidone in an amount at least twice the molar equivalent of the total number of moles of the first compound and the second compound, the homogeneity of the material is easily maintained, and CO ２Alternatively, an intermetallic compound with good conversion efficiency can be obtained in the synthesis of methanol from CO. The mixing method is not particularly limited and may be determined appropriately depending on the container and the amount of solution used. For example, stirring may be performed at 50°C to 95°C for 10 minutes to 5 hours, or at 80°C to 95°C for 1 hour to 2 hours.

[0052] Next, the mixture obtained by mixing the first compound and the second compound is dehydrated to obtain a dehydrated product. The method for dehydrating the mixture obtained by mixing the first compound and the second compound is not particularly limited. Here, "dehydration" refers to the general removal of water, and includes not only drying the mixture but also the removal of water as a solvent. For example, when the mixture is a 6% aqueous nitric acid solution in which the first compound and the second compound are dissolved, the aqueous solution is heated to a predetermined temperature (e.g., 80°C or higher) using a mantle heater and reacted until the water in the aqueous solution is completely removed, thereby obtaining a dehydrated product.

[0053] (Second Step S2) In the second step S2, the dehydrated product obtained in the first step S1 is calcined under atmospheric pressure to obtain a calcined product. The method for calcining the dehydrated product is not particularly limited. For example, the calcined product may be obtained by heating the dehydrated product obtained in the first step S1 in a temperature range of 450°C to 600°C for one hour or more. The calcined product is, for example, an oxide of the first metal atom and an oxide of the second metal atom.

[0054] (Third step S3) In the third step S3, the fired product obtained in the second step S2 is treated with NH ３ The fired product is subjected to a heat treatment under a temperature of 1000° C. or less. As a result, the intermetallic compound according to this embodiment or an intermetallic compound-containing material containing the same can be obtained. ３ The method of heat treatment is not particularly limited. For example, the fired product obtained in the second step S2 may be heated with NH ３ The mixture is heated at a temperature described below for 6 hours or longer under a temperature range of 300°C to 800°C, for example. The heating temperature is preferably in the range of 300°C to 700°C, and more preferably in the range of 400°C to 600°C.

[0055] Incidentally, in the intermetallic compound according to this embodiment, when a polycoordinate atom exhibiting polycoordinate property is contained (for example, PdZnN ｘ ), it is heated in Ar gas (for example, at about 700°C) to eliminate the multi-coordinated atom (for example, N) contained in the crystal lattice, thereby obtaining an intermetallic compound (for example, PdZn) that does not contain the multi-coordinated atom. Furthermore, in the case where the intermetallic compound-containing substance according to this embodiment contains at least one of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom (for example, PdZnNx / ZnO), it is possible to obtain an intermetallic compound (for example, PdZnNx / ZnO) that does not contain the multi-coordinated atom by NH ３ By heating the mixture in an air stream (e.g., at about 900°C) to volatilize or eliminate the components constituting the oxide or nitride, an intermetallic compound (e.g., PdZnNx) can be obtained that does not contain the oxide or nitride. In this manner, an intermetallic compound-containing material containing at least one of the oxide or nitride (including an intermetallic compound containing a multicoordinating atom that exhibits multicoordination) is first obtained. Next, from the obtained intermetallic compound, an intermetallic compound containing the coordinating atom (wherein the oxide or nitride is not coexisting) is obtained. Next, by obtaining an intermetallic compound that does not contain the multicoordinating atom from the obtained intermetallic compound, each substance can be produced separately (see FIG. 9).

[0056] <Catalyst> Next, a catalyst containing the intermetallic compound or intermetallic compound-containing material according to this embodiment will be described. The catalyst according to this embodiment includes a catalyst containing the intermetallic compound or intermetallic compound-containing material according to this embodiment and a carrier that supports the intermetallic compound or the intermetallic compound-containing material. A carrier may be omitted, and the intermetallic compound or intermetallic compound-containing material according to this embodiment may be used alone as a catalyst. Such a catalyst is particularly effective in reducing CO ２ It is preferable to use it as a catalyst for methanol synthesis from

[0057] (Carrier) The carrier is not particularly limited as long as it can support the intermetallic compound or intermetallic compound-containing material according to this embodiment and does not inhibit the desired chemical reaction, such as the hydrogenation reaction of carbon dioxide or the hydrogenation reaction of carbon monoxide. Any known carrier may be used as such a carrier. Examples of such carriers include inorganic oxide carriers such as silicon oxide (silica), zinc oxide, aluminum oxide (alumina), magnesium oxide (magnesia), indium oxide, calcium oxide, zirconium oxide (zirconia), titanium oxide (titania), hafnium oxide, barium oxide, cerium oxide (ceria), and oxides of two or more metals, such as perovskite-type compounds and mayenite-type compounds; Ta ３ N ５ , BN, Si ３ N ４ carbon supports such as activated carbon and silicon carbide; and composites of two or more supports selected from the above supports.

[0058] A known method may be used to support the intermetallic compound or intermetallic compound-containing material according to this embodiment on a carrier. For example, the intermetallic compound or intermetallic compound-containing material according to this embodiment may be physically mixed with a carrier, or the intermetallic compound or intermetallic compound-containing material according to this embodiment may be coated on a carrier. Alternatively, a carrier carrying the intermetallic compound or intermetallic compound-containing material may be produced by mixing the first compound, the second compound, and polyvinylpyrrolidone with a carrier and then performing the above-mentioned first step S1 to third step S3.

[0059] <Method for Producing Methanol> The method for producing methanol according to this embodiment includes a step of bringing hydrogen and at least one of carbon monoxide and carbon dioxide into contact with the intermetallic compound or intermetallic compound-containing material according to this embodiment. This allows methanol to be obtained. The method for producing methanol according to this embodiment may use only carbon monoxide, only carbon dioxide, or a mixed gas of carbon monoxide and carbon dioxide. The synthesis of methanol by the reaction of hydrogen and carbon monoxide is as shown in the following formula (1), and the synthesis of methanol by the reaction of hydrogen and carbon dioxide is as shown in the following formula (2). CO + 2H ２ →CH ３ OH...(1) CO ２ +3H ２ →CH ３ OH+H ２ O (2) The Pd content in the intermetallic compound or the substance containing an intermetallic compound is, for example, 0.1 wt % to 50 wt %, and preferably 1 wt % to 50 wt %.

[0060] The method for contacting hydrogen and at least one of carbon monoxide and carbon dioxide with the intermetallic compound or intermetallic compound-containing material according to this embodiment is not particularly limited. For example, a fixed-bed flow reactor may be used, and at least one of carbon dioxide and carbon monoxide may be introduced into the reactor in accordance with the above reaction formula, and hydrogen may be reacted with at least one of carbon dioxide and carbon monoxide. The at least one of carbon dioxide and carbon monoxide and hydrogen may be introduced into the reactor together with an inert gas. The inert gas used may be, for example, Ar.

[0061] The reaction temperature of hydrogen with at least one of carbon monoxide and carbon dioxide is, for example, in the range of room temperature (e.g., 25° C.) to 300° C. Preferably, the range is 150° C. to 250° C. Methanol can be synthesized at low temperatures by using the intermetallic compound or intermetallic compound-containing material according to this embodiment.

[0062] The pressure during the reaction of hydrogen with at least one of carbon monoxide and carbon dioxide is, for example, in the range of atmospheric pressure (for example, 0.1 MPa) to 2.0 MPa. By increasing the pressure, the intermetallic compound or the intermetallic compound-containing material can be easily reacted with CO ２ Alternatively, in the synthesis of methanol from CO, the conversion efficiency can be further improved.

[0063] <Method for Producing Carbon Monoxide> In the method for producing carbon monoxide according to this embodiment, hydrogen and carbon dioxide are brought into contact with the intermetallic compound or intermetallic compound-containing material according to this embodiment. Carbon monoxide is synthesized by the reaction of hydrogen and carbon dioxide as shown in the following formula (3): CO ２ +H ２ →CO+H ２ O (3) The Pd content in the intermetallic compound or the substance containing an intermetallic compound is, for example, 0.1 wt % to 50 wt %, and preferably 5 wt % to 50 wt %.

[0064] The method for contacting hydrogen and carbon dioxide with the intermetallic compound or intermetallic compound-containing material according to this embodiment is not particularly limited. For example, a fixed-bed flow reactor may be used, and carbon dioxide and hydrogen may be introduced into the reactor in accordance with the reaction formula (3) above to cause a reaction. Carbon dioxide and hydrogen may be introduced into the reactor together with an inert gas. The inert gas used may be, for example, Ar.

[0065] The reaction temperature between hydrogen and carbon dioxide is, for example, in the range of 200° C. to 300° C. Preferably, the range is 200° C. to 300° C. By using the intermetallic compound according to this embodiment, carbon monoxide can be synthesized at low temperatures.

[0066] The pressure during the reaction of hydrogen and carbon dioxide is from atmospheric pressure (for example, 0.1 MPa) to 2.0 MPa. By increasing the pressure, ２ In the synthesis of carbon monoxide from ethanol, the conversion efficiency can be further improved.

[0067] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. In addition, the components in the above-described embodiments can be appropriately replaced with well-known components, and can also be appropriately combined with well-known components, without departing from the spirit of the present invention.

[0068] Next, examples of the present invention will be described, but the conditions in the examples are merely examples adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to these examples. Various conditions can be adopted in the present invention as long as they do not deviate from the gist of the present invention and the object of the present invention is achieved.

[0069] (Example 1) "Synthesis of PdZnNx / ZnO" (Part 1) Zn(NO ３ ) ２ ・6H ２ O (99.9%, Fujifilm Wako Co., Ltd.) and Pd(CH ３ COO) ２ (98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and PdO (Pd:Zn = 1:19 as the molar ratio of the metals in the raw materials) were used as raw materials. The raw materials were stirred in a 6% aqueous nitric acid solution together with 3 times the equivalent of polyvinylpyrrolidone (PVP) K30 (manufactured by Fujifilm Wako Co., Ltd.) relative to the total amount of the metal sources at 90°C for 3 hours to obtain 100 ml of a solution (mixture). The obtained solution was transferred to a drying container and then heated to 110°C in an oven to dry and dehydrate until all moisture was removed, thereby obtaining a dehydrated product (gel). The obtained dehydrated product was calcined in air at 500°C for 2 hours to obtain a calcined product (oxide precursor (ZnO + PdO)). The obtained oxide precursor was dissolved in NH ３ The catalyst of Example 1, which is an intermetallic compound-containing material (bcc-PdZnN ｘ / ZnO (Pd = 5 wt%, x = 0.5) was obtained. ｘ The PdZnO (Pd = 5 wt%) was in powder form (average particle size: 100 μm or less). ｘ / ZnO" means PdZnN ｘand ZnO form a composite in a form having an interface between them, namely, PdZnN ｘ It means a substance in which a ZnO phase and a ZnO phase coexist.

[0070] <Powder X-ray Diffraction Measurement> The intermetallic compound-containing material (bcc-PdZnN ｘ Powder X-ray diffraction measurements were performed using a sample of ZnO (Pd = 5 wt%). The measurements were performed using a Bruker X-ray diffractometer (D2 Phaser) and CuKα as the X-ray source. The measurement temperature was room temperature (25°C), the measurement angle range was 10 to 80°, the scan speed was 0.2 seconds / step, and the scan step was 0.01°. The obtained X-ray diffraction spectrum is shown in Figure 2. As is clear from Figure 2, the X-ray diffraction spectrum of the intermetallic compound-containing material, which is the catalyst of Example 1, had peaks at diffraction angles 2θ between 31.5 and 32°, between 34 and 34.5°, and between 36 and 36.5°, confirming the presence of a ZnO phase. Furthermore, the intermetallic compound-containing substance that is the catalyst of Example 1 contains a crystal lattice in which Pd and Zn are present in adjacent positions, and in the X-ray diffraction spectrum of the intermetallic compound according to this embodiment before the thermal desorption measurement, there is a first peak between 40.5° and 41.5° as a diffraction angle 2θ, and there is a second peak between 43.5° and 44.5°, and the positions of the first and second peaks are different from the peak position of Pd alone (40.1°) and the peak position of Zn alone (43.2°), confirming the presence of a PdZn phase.

[0071] (Temperature Programmed Desorption Measurement) Temperature programmed desorption measurement is performed using a BELCAT II manufactured by MicrotracBEL. Specifically, the temperature programmed desorption measurement is performed by using a 50 mg sample and heating the sample in an Ar atmosphere from room temperature (25°C) to 700°C at a rate of 10°C / min, and then holding at 700°C for 1 hour. The gas species desorbed from the sample during this measurement are analyzed using a mass spectrometer attached to a catalyst analyzer (e.g., a BELCAT II manufactured by MicrotracBEL). In this temperature programmed desorption measurement, a signal with a mass number of 28, i.e., a signal derived from the release of nitrogen molecules, was confirmed. This indicates that a multi-coordinate atom (nitrogen atom) exhibiting multi-coordinate property has been introduced between the crystal lattices of the intermetallic compound contained in the intermetallic compound-containing material before the temperature programmed desorption measurement.

[0072] <BET Specific Surface Area> The BET specific surface area of ​​the intermetallic compound-containing material, which was the catalyst of Example 1, was measured using a specific surface area / pore distribution measuring device (specifically, a BELSORP-mini II manufactured by Microtrac-Bell) with nitrogen (purity 99.99995%) as the adsorption gas and the adsorption temperature at the liquid nitrogen temperature (-196°C). As a result, the BET specific surface area was 18.9 m ２ / g, and the BET specific surface area of ​​the intermetallic compound-containing material, which is the catalyst of Example 1, is 1 m ２ / g or more.

[0073] <Composition Analysis> The composition of the intermetallic compound-containing material, which is the catalyst of Example 1, was evaluated by the above-mentioned method, and as a result, it was confirmed to be represented by the following composition formula: PdZnN ０．５ / ZnO.

[0074] <CO ２ The effect of the catalyst on the reaction of carbon dioxide with hydrogen under atmospheric pressure (0.1 MPa) was evaluated. Specifically, the rate of methanol synthesis from carbon dioxide gas (CO ２ ) and hydrogen gas (H ２ ) was brought into contact with the intermetallic compound-containing material, which was the catalyst of Example 1, to carry out a methanol synthesis reaction in the following manner. ２The mixture was pretreated under an air stream at 300°C for 2 hours. Then, a synthesis reaction was carried out in a fixed-bed flow reactor using a reaction tube packed with 0.1 g of catalyst in a glass tube. The gas flow rate during the reaction was 1000kJ / 2000kcal / 2 ...cal. ２ : 10 mL min －１ , H ２ : 30 mL min －１ , Ar: 10mL min －１ , total 50mL min －１ The reaction temperature was 100°C to 250°C. An Agilent Gas Chromatograph 7890A was used to analyze the amount of methanol produced in measuring the methanol synthesis rate. An Agilent DB-1 column was used, and the column temperature was 50°C to 200°C. The flow path from the reactor to the gas chromatograph analyzer was heated to 90°C or higher using a tube heater. When the synthesis reaction conditions were 0.1 MPa and 200°C, the methanol synthesis rate was 437 μmol / g / h. When the synthesis reaction conditions were 0.1 MPa and 250°C, the methanol synthesis rate was 1118 μmol / g / h. The results are shown in Table 1. The reaction temperature dependence of the methanol synthesis rate was also evaluated. The results are shown in Figure 3.

[0075] <CO ２ The effect of the catalyst loading amount on the rate of carbon monoxide (CO) generation was evaluated by the reaction of carbon dioxide with hydrogen under normal pressure (0.1 MPa). ２ ) and hydrogen gas (H ２ ) was brought into contact with the intermetallic compound-containing material, which was the catalyst of Example 1, to carry out a carbon monoxide production reaction in the following manner. ２ The mixture was pretreated under an air stream at 300°C for 2 hours. Then, a synthesis reaction was carried out in a fixed-bed flow reactor using a reaction tube packed with 0.1 g of catalyst in a glass tube. The gas flow rate during the reaction was 1000kJ / 2000kcal / 2 ...cal. ２ : 10 mL min －１ , H ２ : 30 mL min －１ , Ar: 10mL min －１ , total 50mL min －１The reaction temperature was 250°C. An Agilent Gas Chromatograph 7890A was used to analyze the amount of methanol produced in measuring the carbon monoxide production rate, and an Agilent SHINCARBON-ST column was used, with the column temperature set to 50°C to 200°C. The flow path from the reactor to the gas chromatograph analyzer was heated to 90°C or higher using a tube heater. The carbon monoxide production rate when the production reaction conditions were 0.1 MPa and 250°C was 1540 μmol / g / h. The results are shown in Table 2.

[0076] <Methanol synthesis selectivity> In the same manner as above, carbon dioxide and hydrogen are reacted to produce methane (CH ４ ), carbon monoxide (CO), C ２ The amount of methane (CH4) produced was also measured in accordance with the method commonly used in the art, similar to the method for analyzing the amount of methanol produced. The amount of each product produced was measured by the following method. From the measurement results obtained, the synthesis selectivity for each product was calculated and evaluated. The results are shown in Figure 4. ４ An Agilent Gas Chromatograph 7890A was used to analyze the amount of methane produced in measuring the synthesis rate of methane. An Agilent DB-1 column was used, and the column temperature was set to 50°C to 200°C. An Agilent Gas Chromatograph 7890A was used to analyze the amount of carbon monoxide produced in measuring the carbon monoxide (CO) production rate. An Agilent SHINCARBON-ST column was used, and the column temperature was set to 50°C to 200°C. ２ C in measuring synthesis rate ２ The amount of produced methanol was analyzed using a gas chromatograph 7890A manufactured by Agilent. The column used was a DB-1 manufactured by Agilent, and the column temperature was set to 50°C to 200°C. The methanol synthesis selectivity was calculated using the following formula (1): Methanol synthesis selectivity = 100 x F ｍｅｔｈａｎｏｌ，ｏｕｔ / (F ｍｅｔｈａｎｏｌ，ｏｕｔ + F ＣＯ，ｏｕｔ + F ＣＨ４，ｏｕｔ + F Ｃ２，ｏｕｔ ) (1)

[0077] (Examples 2 to 6) "PdZnN ｘ / ZnO synthesis (part 2) Zn(NO ３ ) ２ ・6H ２ O and Pd(CH ３ COO) ２ By adjusting the ratio of PdZnN ｘ PdZnN in Examples 2 to 6 were prepared in the same manner as in Example 1, except that the Pd content in ZnO was changed from 5 wt% in Example 1 to 0.2 wt%, 1 wt%, 10 wt%, 25 wt%, and 50 wt%, respectively. ｘ / ZnO (wt%, x = 0.1 to 0.6) was obtained. ｘ Using PdZnN / ZnO as a sample, powder X-ray diffraction measurements were carried out using the same method as in Example 1. The results are shown in Figure 5. ｘ The methanol synthesis rates of PdZnN / ZnO were measured under various synthesis reaction temperature conditions in the same manner as in Example 1. The results are shown in Figure 6. The methanol synthesis rates when the synthesis reaction temperature conditions were 200°C and 250°C are shown in Table 1 below. ｘ The CO production rate when the temperature condition of the production reaction was 250°C is shown in Table 2 below. ｘ The methanol synthesis selectivity of each of the catalysts prepared from ZnO was measured under various synthesis reaction temperature conditions in the same manner as in Example 1. The results are shown in Table 3.

[0078]

[0079]

[0080]

[0081] (Example 7) Using the PdZnNx / ZnO (25 wt%) obtained in Example 5, a long-term stability evaluation was carried out by the following method. The results are shown in Figure 7. "Long-term Stability Evaluation" Specifically, the PdZnNx / ZnO was heated under high pressure (0.9 MPa) with carbon dioxide gas (CO ２ ) and hydrogen gas (H ２) was brought into contact with the intermetallic compound-containing material, which was the catalyst of Example 5, and the methanol synthesis reaction was carried out for a long period of time in the following manner. First, before starting the synthesis reaction, H ２ The mixture was pretreated under an air stream at 300°C for 2 hours. Then, a synthesis reaction was carried out in a fixed-bed flow reactor using a reaction tube packed with 0.1 g of catalyst in a steel tube. The gas flow rate during the reaction was 1000kJ / 2000kcal / 3000kJ / 4000kcal / 5000kJ / 6000kcal / 7000kcal. ２ : 10 mL min －１ , H ２ : 30 mL min －１ , Ar: 10mL min －１ , total 50mL min －１ The reaction temperature was 100°C, the reaction pressure was 0.9 MPa, and the reaction time was 0 to 50 hours. The amount of methanol produced at the methanol synthesis rate was analyzed in the same manner as in Example 1, and the methanol synthesis rate was calculated based on the obtained measurements. The results are shown in Figure 7. Table 4 below shows the methanol synthesis rate when the synthesis reaction conditions were high pressure (0.9 MPa) and 200°C. Furthermore, using the same method as in Example 1, the methanol synthesis selectivity was measured under various synthesis reaction temperature conditions when the synthesis reaction conditions were high pressure (0.9 MPa). The results are shown in Table 5 and Figure 11.

[0082] (Example 8) Using the PdZnNx / ZnO (50 wt%) obtained in Example 6, a long-term stability evaluation was carried out in the same manner as in Example 7, except that the reaction temperature was 250° C. The results are shown in FIG.

[0083]

[0084]

[0085] (Comparative Example 1) “CuZnOAl ２ O ３ Synthesis of Cu / ZnO / Al pellets ２ O ３ (manufactured by Alfa Aesar Corporation) was pulverized using an agate mortar and pestle to obtain a powder, which was used as the catalyst of Comparative Example 1.

[0086] <Methanol synthesis rate> CuZnOAl ２ O３ The same method as in Example 1 was used except that CO ２ The hydrogenation reaction of the above was carried out, and the reaction temperature dependency of the methanol synthesis rate was evaluated. The results are shown in Figure 3. Table 1 shows the methanol synthesis rate when the synthesis reaction temperature conditions were 200°C and 250°C.

[0087] <CO production rate> CuZnOAl ２ O ３ The CO production rate was measured in the same manner as in Example 1 except that the temperature condition of the production reaction was 250° C., and is shown in Table 2.

[0088] <CO ２ Selectivity for methanol synthesis from CuZnOAl ２ O ３ The same method as in Example 1 was used except that CO ２ The methanol synthesis selectivity was evaluated under various synthesis reaction temperature conditions. The results are shown in Figure 8. Table 3 shows the methanol synthesis selectivity when the synthesis reaction temperature was 200°C.

[0089] (Example 9) "PdZnN ｘ Synthesis of PdZnN obtained in Example 5 ｘ / ZnO (25 wt% Pd) with NH ３ By heating at 900°C in an air stream, PdZnN ｘ (50 wt% Pd, x = 0.2) was obtained. By heating, the Zn component was evaporated, and PdZnN ｘ Only that remained.

[0090] The obtained PdZnN ｘ The powder X-ray diffraction measurement was carried out using the same method as in Example 1. The results are shown in Figure 9. ｘ The synthesis reaction was carried out in the same manner as in Example 1 except that CO ２The hydrogenation reaction of PdZnN obtained in Example 5 was carried out, and the reaction temperature dependency of the methanol synthesis rate was evaluated at reaction temperatures of 100 to 250°C. The results are shown in Figure 10. The methanol synthesis rates when the synthesis reaction temperature conditions were 200 and 250°C are also shown in Table 6. For comparison, the methanol synthesis rates of PdZnN obtained in Example 5 were also evaluated. ｘ The same method as in Example 1 was used except that CO / ZnO (25 wt % Pd) was used and the synthesis reaction was carried out under high pressure (0.9 MPa). ２ The reaction temperature dependency of the methanol synthesis rate was evaluated at reaction temperatures of 150°C to 250°C. The results are shown in Figure 10. Table 6 shows the methanol synthesis rates when the synthesis reaction temperature conditions were 200°C and 250°C.

[0091] (Example 10) "Synthesis of PdZn" PdZnN obtained in Example 9 ｘ PdZn (50 wt % Pd) was obtained by heating this at 700° C. in an Ar stream. The nitrogen in the lattice was eliminated by heating, leaving only PdZn.

[0092] The obtained PdZn was subjected to powder X-ray diffraction measurement using the same method as in Example 1. The results are shown in Figure 9. CO was synthesized using the same method as in Example 1, except that PdZn was used as the catalyst and the synthesis reaction was carried out under high pressure (0.9 MPa). ２ The hydrogenation reaction was carried out and the reaction temperature dependency of the methanol synthesis rate was evaluated at reaction temperatures of 250°C to 350°C. The results are shown in Figure 10. The methanol synthesis rate at a temperature condition of 250°C was 15 µmol / g / h. The results are shown in Table 6.

[0093] <Methanol synthesis rate from CO> ２ Methanol synthesis rate from CO ２ The rate of methanol synthesis from CO is evaluated in the same manner as above, except that CO is used as the raw material gas instead of the methanol.

[0094] <Reference Control Example> As a reference control, a catalyst intermetallic compound or an intermetallic compound-containing substance was synthesized according to the same method as in Example 1, except that instead of polyvinylpyrrolidone (PVP) used, another compound was added, or no compound was added. As a result, by comparing the X-ray diffraction spectrum of the catalyst intermetallic compound or intermetallic compound-containing substance obtained in the synthesis system containing polyvinylpyrrolidone (PVP) with the X-ray diffraction spectra of the catalyst intermetallic compound or intermetallic compound-containing substance obtained in the synthesis system containing other compounds and the synthesis system containing no compounds, it was confirmed that the peak position of the catalyst intermetallic compound or intermetallic compound-containing substance obtained in the synthesis system containing polyvinylpyrrolidone (PVP) was shifted to a lower value. From this, it was found that the lattice distance of the crystal lattice of the catalyst intermetallic compound or intermetallic compound-containing substance obtained in the synthesis system containing polyvinylpyrrolidone (PVP) was widened, resulting in a higher N (nitrogen) content.

[0095] (Example 11) "Pd ２ In ３ / InN (In ２ O ３ Synthesis of In(NO ３ ) ３ ・3H ２ O (99.9%, Kanto Chemical Co., Ltd.) and Pd(CH ３ COO) ２ (98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and In (Pd:In = 1:19 as the molar ratio of metals in the raw materials) were used as raw materials. The raw materials were stirred in a 6% aqueous nitric acid solution together with 3 times the equivalent of polyvinylpyrrolidone (PVP) K30 (manufactured by Fujifilm Wako Co., Ltd.) relative to the total amount of metal sources at 90°C for 3 hours to obtain 100 ml of a solution (mixture). The obtained solution was transferred to a drying container and then heated to 110°C in an oven to dry and dehydrate until all water was removed, thereby obtaining a dehydrated product (gel). The obtained dehydrated product was baked in air at 500°C for 2 hours (1°C / min) to obtain a baked product (oxide precursor (In ２ O ３The resulting oxide precursor was treated with NH ３ The catalyst of Example 11, which is an intermetallic compound-containing material (Pd ２ In ３ / InN+In ２ O ３ (Pd=5 wt%) was obtained. ２ In ３ / InN+In ２ O ３ (Pd = 5 wt%) was in powder form (average particle size: 100 μm or less). ２ In ３ / InN+In ２ O ３ " means Pd ２ In ３ and InN and In ２ O ３ and are mixed together, for example, Pd ２ In ３ / InN and In ２ O ３ and a composite material in which a composite is formed in a form having an interface between the two, that is, Pd ２ In ３ / InN phase and In ２ O ３ It means a substance in which phases coexist.

[0096] (Example 12) "Pd ２ Synthesis of Ga / GaN (sol-gel method) Ga(NO ３ ) ３ ・8H ２ O (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) and Pd(CH ３ COO) ２(98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and Ga were used as raw materials (the molar ratio of metals in the raw materials was Pd:Ga = 1:19). The raw materials were stirred in a 6% aqueous nitric acid solution together with 3 times the equivalent of polyvinylpyrrolidone (PVP) K30 (manufactured by Fujifilm Wako Co., Ltd.) relative to the total amount of the metal sources at 90°C for 3 hours to obtain 100 ml of a solution (mixture). The obtained solution was transferred to a drying container and then heated to 110°C in an oven to dry and dehydrate until all water was removed, thereby obtaining a dehydrated product (gel). The obtained dehydrated product was calcined in air at 500°C for 2 hours to obtain a calcined product (oxide precursor (Ga ２ O ３ The resulting oxide precursor was treated with NH ３ The catalyst of Example 12, which is an intermetallic compound-containing material (Pd ２ Ga / GaN (Pd=5 wt%) was obtained. ２ The Ga / GaN (Pd=5 wt%) was in powder form (average particle size: 100 μm or less). ２ "Ga / GaN" means Pd ２ A mixture of Ga and GaN, for example, Pd ２ A composite material in which Ga and GaN form a composite with an interface between them, i.e., Pd ２ It means a substance in which Ga phase and GaN phase coexist.

[0097] The composite materials obtained in Examples 11 and 12 were used as samples and subjected to powder X-ray diffraction measurement in the same manner as in Example 1. The results are shown in Figures 12 and 13.

[0098] The composite materials obtained in Examples 11 and 12 were also measured for their methanol synthesis rates at various synthesis reaction temperatures of 200°C and 250°C using the same method as in Example 1. The results are shown in Table 7. The composite materials obtained in Examples 11 and 12 were also measured for their CO production rates at a synthesis reaction temperature of 250°C using the same method as in Example 1. The results are shown in Table 8 below. The composite materials obtained in Examples 11 and 12 were also measured for their methanol synthesis selectivity at a synthesis reaction temperature of 200°C using the same method as in Example 1. The results are shown in Table 9.

[0099] The methanol synthesis rate of the composite material obtained in Example 12 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The results are shown in Figure 16. The CO production rate of the composite material obtained in Example 12 under various synthesis reaction temperature conditions using the same method as in Example 1 is shown in Figure 17. The methanol synthesis selectivity of the composite material obtained in Example 12 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The results are shown in Figure 18.

[0100] (Example 13) "Pd ２ Ga / Ga ２ O ３ Synthesis of Ga(NO ３ ) ３ ・8H ２ O (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) and Pd(CH ３ COO) ２ (98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and Ga were used as raw materials (the molar ratio of metals in the raw materials was Pd:Ga = 1:19). The raw materials were mixed with 3 times the equivalent of polyvinylpyrrolidone (PVP) K30 (manufactured by Fujifilm Wako Co., Ltd.) relative to the total amount of metal sources in a 6% aqueous nitric acid solution and stirred at 90°C for 3 hours to obtain 100 ml of a solution (mixture). The resulting solution was transferred to a drying container, and then heated to 110°C in an oven and dried and dehydrated (18 hours) until all water was removed, obtaining a dehydrated product (gel). The resulting dehydrated product was then calcined in air at 500°C for 2 hours (1°C / min) to obtain a calcined product (oxide precursor (Ga ２ O ３The resulting oxide precursor was treated with NH ３ The catalyst of Example 13, which is an intermetallic compound-containing material (Pd ２ Ga / Ga ２ O ３ (Pd=5wt%, Ga ２ O ３ The obtained Pd ２ Ga / Ga ２ O ３ (Pd=5wt%, Ga ２ O ３ The Pd (γ-body) was in powder form (average particle size: 100 μm or less). ２ Ga / Ga ２ O ３ " means Pd ２ Ga and Ga ２ O ３ and are mixed together, for example, Pd ２ Ga and Ga ２ O ３ and a composite material in which a composite is formed in a form having an interface between the two, that is, Pd ２ Ga phase and Ga ２ O ３ It means a substance in which phases coexist.

[0101] The composite material obtained in Example 13 was used as a sample and subjected to powder X-ray diffraction measurement in the same manner as in Example 1. The results are shown in FIG.

[0102] The composite material obtained in Example 13 was also measured for its methanol synthesis rate when the temperature conditions for the synthesis reaction were 200°C and 250°C, using the same method as in Example 1. The results are shown in Table 7. The composite material obtained in Example 13 was also measured for its CO production rate when the temperature condition for the synthesis reaction was 250°C, using the same method as in Example 1. The results are shown in Table 8 below. The composite material obtained in Example 13 was also measured for its methanol synthesis selectivity when the temperature condition for the synthesis reaction was 200°C, using the same method as in Example 1. The results are shown in Table 9.

[0103] The methanol synthesis rate of the composite material obtained in Example 13 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The results are shown in Figure 16. The CO production rate of the composite material obtained in Example 13 under various synthesis reaction temperature conditions using the same method as in Example 1 is shown in Figure 17. The methanol synthesis selectivity of the composite material obtained in Example 13 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The results are shown in Figure 18.

[0104]

[0105]

[0106]

[0107] (Example 14) "Pd ２ Synthesis of Ga / GaN (physical mixing method) (using commercially available GaN) Ga(NO ３ ) ３ ・8H ２ O (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) and Pd(CH ３ COO) ２ A mixture of Pd (98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and GaN (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) was mixed with the raw material (the molar ratio of metals in the raw material was Pd:Ga = 1:19). ３ The mixture was heated at 600°C for 2 hours under an air flow. ２ Ga / GaN (Pd=5 wt%) was obtained. ２ The Ga / GaN (Pd=5 wt%) was in powder form (average particle size: 100 μm or less). ２ "Ga / GaN" means Pd ２ A mixture of Ga and GaN, for example, Pd ２ A composite material in which Ga and GaN form a composite with an interface between them, i.e., Pd ２ It means a substance in which Ga phase and GaN phase coexist.

[0108] Powder X-ray diffraction measurement was performed on the composite material obtained in Example 14 as a sample using the same method as in Example 1. The results are shown in Figure 15. Furthermore, the methanol synthesis rate of the composite material obtained in Example 14 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The methanol synthesis rates when the synthesis reaction temperature conditions were 200°C and 250°C are shown in Table 10 below.

[0109]

[0110] (Example 15) "Pd ５ Ga ３ / GaN synthesis (physical mixing method) (using commercially available GaN) Ga(NO ３ ) ３ ・8H ２ O (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) and Pd(CH ３ COO) ２ A mixture of Pd (98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and GaN (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) was mixed with the raw material (the molar ratio of metals in the raw material was Pd:Ga=1:19). ２ The mixture was heated at 400°C for 2 hours under an air flow. ５ Ga ３ / GaN (Pd = 5 wt%) was obtained. ５ Ga ３ The Pd / GaN (Pd = 5 wt%) was in powder form (average particle size: 100 μm or less). ５ Ga ３ / GaN" refers to Pd ５ Ga ３ and GaN are mixed, for example, Pd ５ Ga ３ and GaN form a composite in a form having an interface between them, namely, Pd ５ Ga ３ The term "GaN" refers to a substance in which the GaN phase and the GaN phase coexist.

[0111] Powder X-ray diffraction measurement was performed on the composite material obtained in Example 15 as a sample using the same method as in Example 1. The results are shown in Figure 19. Furthermore, the methanol synthesis rate of the composite material obtained in Example 15 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The results are shown in Figure 20. Furthermore, the methanol synthesis rates when the synthesis reaction temperature conditions were 200°C and 250°C are shown in Table 10 below.

[0112] (Example 16) "Synthesis of PdGa / GaN" (Physical Mixing Method) (Commercially Available GaN Used) Ga(NO ３ ) ３ ・8H ２ O (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) and Pd(CH ３ COO) ２ A mixture of Pd (98%, manufactured by Tokyo Chemical Industry Co., Ltd.) and GaN (99.99%, manufactured by Kojundo Chemical Laboratory Co., Ltd.) was mixed with the raw material (the molar ratio of metals in the raw material was Pd:Ga=1:19). ２ The mixture was heated at 600°C for 2 hours under an air flow. An intermetallic compound-containing material (PdGa / GaN (Pd = 5 wt%)) was obtained, which is the catalyst of this example. The obtained PdGa / GaN (Pd = 5 wt%) was in powder form (average particle size: 100 µm or less). Here, "PdGa / GaN" refers to a state in which PdGa and GaN are mixed together, for example, a composite material in which PdGa and GaN form a complex with an interface between them, i.e., a material in which a PdGa phase and a GaN phase coexist.

[0113] Powder X-ray diffraction measurement was performed on the composite material obtained in Example 16 using the same method as in Example 1. The results are shown in Figure 21. Furthermore, the methanol synthesis rate of the composite material obtained in Example 15 was measured under various synthesis reaction temperature conditions using the same method as in Example 1. The results are shown in Figure 22. Table 10 shows the methanol synthesis rates for synthesis reaction temperatures of 200°C and 250°C. Examples 11, 12, and 13 all represent intermetallic compounds / intermetallic compound-containing materials prepared by the sol-gel method. On the other hand, Examples 14, 15, and 16 all represent intermetallic compounds / intermetallic compound-containing materials prepared by the physical mixing method. Both the former and latter materials utilize intermetallic compounds with excellent crystalline structural stability, demonstrating excellent methanol synthesis selectivity and long-term durability. However, differences in the methanol synthesis rate were observed between the former and latter materials. As will be described in the following (Consideration 2), it is believed that the difference in catalytic activity and selectivity occurs depending on the level of stability in terms of the crystal structure of the intermetallic compound and the level of effective interaction at the interface formed between the intermetallic compound and the corresponding support such as oxide or nitride. Thus, although the latter material exhibits methanol synthesis selectivity and excellent long-term durability, it is basically inferior to the former material in terms of its methanol synthesis rate. Furthermore, the CuZnOAl ２ O ３ It was found that there are cases where the quality is the same as or slightly inferior to that of the original.

[0114] (Discussion) From Figure 2, it was confirmed that a PdZn intermetallic compound was synthesized, as the X-ray diffraction pattern of ZnO and peaks derived from the PdZn intermetallic compound were observed. By heating in ammonia using this synthesis method, Pd and Zn react to form PdZn on the ZnO. Furthermore, from Figures 5 and 9, the peaks derived from PdZn are shifted to the lower angle side, suggesting that N has been introduced into the PdZn lattice. From the results of temperature-programmed desorption measurements in an inert gas, it was found that N with a mass number of 28 was introduced into the PdZn lattice. ２The detection of a peak derived from gas indicates that the PdZn intermetallic compound contains N, and the amount of N released indicates that the composition is PdZnN ０．５ It is thought that this is the case.

[0115] CO ２ When the methanol synthesis reaction from Cu / ZnO / Al and hydrogen was carried out at 0.1 MPa, it functioned as a catalyst, and its activity was higher than that of a PdMo-based catalyst, as shown in Figure 3. Furthermore, it had excellent methanol synthesis selectivity and was ２ O ３ Methanol was produced more selectively than with methyl methyl ketone (Fig. 4, Fig. 8).

[0116] When the Pd content was increased and materials were synthesized, the peaks derived from the PdZn intermetallic compound shifted to lower angles in all samples, regardless of the Pd content, suggesting the introduction of N (Fig. 5). The sample containing 25 wt% Pd had the highest catalytic activity, and the increase in active sites is thought to be the cause of the improved activity (Fig. 6). ｘ This catalyst is believed to operate stably for a long period of time, and the lattice nitrogen is also stable without being released during the reaction (Figure 7).

[0117] PdZnN containing 25 wt% Pd ｘ / ZnO to NH ３ By heating at 900°C in an air stream, PdZnN containing no ZnO was obtained. ｘ Furthermore, by heating this PdZnNx at 700 °C in an Ar gas flow, the nitrogen in the PdZn lattice was eliminated, and PdZn was synthesized (Fig. 9). As shown in Fig. 9, PdZnNx before nitrogen elimination ｘ / ZnO and PdZnN ｘ In the X-ray diffraction pattern of PdZn after nitrogen desorption, it was confirmed that the peak positions of the (111) and (200) planes were shifted to lower angles than those of PdZn (a general alloy) used as a reference. On the other hand, in the X-ray diffraction pattern of PdZn after nitrogen desorption, it was confirmed that the peak positions of the (111) and (200) planes were almost the same as those of PdZn (a general alloy) used as a reference. As in the discussion of Figure 2 above, PdZnN ｘ / ZnO and PdZnNｘ It was suggested that N was introduced into the PdZn lattice.

[0118] PdZnN of Example 9 ｘ showed 33 times higher methanol synthesis activity at 250°C than PdZn in Example 10 (Fig. 10). This indicates that the introduction of N into the lattice significantly improves the methanol synthesis activity compared to PdZn intermetallic compounds. ｘ / ZnO is PdZnN ｘ This shows that the catalytic activity is 8 times higher than that of PdZnN. ｘ This is thought to be because the particles are dispersed on the ZnO, increasing the number of active sites. ｘ Cu / ZnO / Al exhibited excellent methanol synthesis selectivity under 9 atmospheres. Compared with the selectivity under 1 atmosphere (Figure 4), the selectivity was improved in the high temperature range above 200°C. ２ O ３ It can be seen that the methanol synthesis selectivity is superior compared to PdZnN ｘ It was suggested that the Methanol synthesis selectivity of the MgO / ZnO catalyst increases with increasing pressure.

[0119] From the results of Comparative Example 1 shown in FIG. ２ O ３ When a catalyst made of Cu / Zn / Al oxide such as CO2 is used, the methanol synthesis selectivity is poor under high-temperature reaction conditions. Therefore, the catalyst of the present invention, which shows excellent methanol synthesis selectivity even under relatively high-temperature reaction conditions, is ２ This is expected to be useful in the synthesis of methanol from ethanol.

[0120] (Consideration 2) The intermetallic compound-containing material according to this embodiment contains at least one of an oxide of at least one of the first metal atom and the second metal atom, and at least one of a nitride of at least one of the first metal atom and the second metal atom, which contributes to the stability of the crystal structure of the intermetallic compound in high temperature regions, and improves the high temperature resistance of the catalyst containing the intermetallic compound-containing material. The intermetallic compound-containing material also exhibits methanol synthesis selectivity and excellent long-term durability. In addition, in the intermetallic compound-containing material, commercially available GaN is mixed with the intermetallic compound Pd ２ In the case of directly contacting and supporting Ga by a physical mixing method, and causing interaction at the interface formed between the two substances (i.e., Examples 14, 15, and 16), and in the case of synthesizing GaN and an intermetallic compound Pd from an oxide precursor by a sol-gel method, ２ When a more effective interaction occurs at the interface formed between the GaN and Ga (i.e., Examples 11, 12, and 13), the interaction changes the electronic state of the catalytically active site, compared to when the intermetallic compound exists alone, and this is thought to improve the activity and selectivity of the catalyst. In particular, the interaction between GaN synthesized from an oxide precursor by the sol-gel method and the intermetallic compound Pd ２ In order to create a more effective interaction at the interface formed with Ga, commercial GaN is treated with the intermetallic compound Pd ２ Compared to when Ga is directly contacted and supported by a physical mixing method, which causes an interaction at the interface formed between the two substances, the state of the interface formed is better, which is thought to cause a larger change in the electronic state, thereby further improving the activity and selectivity of the catalyst.

Claims

1. An intermetallic compound containing a first metal atom and a second metal atom, comprising a crystal lattice in which the first metal atom and the second metal atom are adjacent to each other, wherein the first metal atom is Pd, and the second metal atom is at least one selected from the group consisting of Zn, In, and Ga, and having a BET specific surface area of ​​1 m ２ / g or more.

2. The intermetallic compound according to claim 1, wherein in an X-ray diffraction spectrum before thermal desorption measurement, the position of the peak of said intermetallic compound is different from the position of the peak of said first metal atom alone and the position of the peak of said second metal atom alone.

3. The intermetallic compound according to claim 2, wherein the first metal atoms are Pd and the second metal atoms are Zn, at least a portion of the crystal lattice has a body-centered cubic (bcc) crystal structure, and in an X-ray diffraction spectrum before thermal desorption measurement, the peak positions of the intermetallic compound, as a diffraction angle 2θ, are as follows: a first peak is between 40.5° and 41.5°, and a second peak is between 43.5° and 44.5°.

4. BET specific surface area is 15m ２ 4. The intermetallic compound according to claim 3, wherein the intermetallic compound has a Mo content of 1.0 / g or more.

5. The intermetallic compound according to claim 3, wherein the volume ratio of the crystal structure of the body-centered cubic lattice (bcc) to the total volume of the intermetallic compound is 50% or more.

6. The intermetallic compound according to claim 1 or 2, wherein the ratio (molar fraction) of the number of moles of the first metal atoms to the total number of moles of the first metal atoms and the second metal atoms contained in the intermetallic compound is 5 mol % or more and 95 mol % or less.

7. The intermetallic compound according to claim 1 or 2, wherein the ratio (molar fraction) of the number of moles of the first metal atoms to the total number of moles of the first metal atoms and the second metal atoms contained in the intermetallic compound is 10 mol % or more and 90 mol % or less.

8. The intermetallic compound according to claim 1 or 2, wherein the molar ratio of said first metal atoms to said second metal atoms is 30:70 to 70:

30.

9. The intermetallic compound according to claim 1 or 2, wherein the molar ratio of said first metal atoms to said second metal atoms is 40:60 to 65:

35.

10. The intermetallic compound according to claim 1 or 2, wherein the molar ratio of said first metal atoms to said second metal atoms is 50:50 to 60:

40.

11. The intermetallic compound according to claim 1 or 2, which contains a polycoordinating atom that exhibits polycoordination.

12. The intermetallic compound according to claim 11, wherein said multi-coordinate atom is one or more selected from the group consisting of N, O, C and B.

13. An intermetallic compound-containing substance comprising the intermetallic compound according to claim 1 or 2 and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom.

14. CO containing intermetallic compounds or intermetallic compound-containing materials ２ 3. A catalyst for methanol synthesis from CO. 4, wherein the intermetallic compound is the intermetallic compound according to claim 1 or 2, and the intermetallic compound-containing substance contains the intermetallic compound and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom. ２ Catalyst for methanol synthesis from .

15. The CO catalyst of claim 14, further comprising a support that supports the intermetallic compound or the intermetallic compound-containing material. ２ Catalyst for methanol synthesis from .

16. CO ２ 3. Use of an intermetallic compound or an intermetallic compound-containing material as a catalyst for methanol synthesis from a metal oxide, the intermetallic compound being the intermetallic compound according to claim 1 or 2, the intermetallic compound-containing material containing the intermetallic compound and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom.

17. A method for producing methanol, comprising contacting hydrogen and at least one of carbon monoxide and carbon dioxide with an intermetallic compound or an intermetallic compound-containing substance, wherein the intermetallic compound is the intermetallic compound defined in claim 1 or 2, and the intermetallic compound-containing substance contains the intermetallic compound and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom.

18. A method for producing carbon monoxide by contacting hydrogen and carbon dioxide with an intermetallic compound or an intermetallic compound-containing substance, wherein the intermetallic compound is the intermetallic compound defined in claim 1 or 2, and the intermetallic compound-containing substance contains the intermetallic compound and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom.

19. A method for producing an intermetallic compound or an intermetallic compound-containing material, wherein the intermetallic compound is an intermetallic compound containing a first metal atom and a second metal atom, the first metal atom is Pd, and the second metal atom is one or more selected from the group consisting of Zn, In, and Ga, and the intermetallic compound-containing material contains the intermetallic compound and at least one selected from the group consisting of an oxide of at least one of the first metal atom and the second metal atom, and a nitride of at least one of the first metal atom and the second metal atom, the method comprising the steps of: a preliminary step of mixing a first compound containing the first metal atom and a second compound containing the second metal atom in the presence of polyvinylpyrrolidone to obtain a mixture; a first step of dehydrating the mixture obtained in the preliminary step to obtain a dehydrated product; a second step of firing the dehydrated product obtained in the first step in the atmosphere to obtain a fired product; and a second step of heating the fired product obtained in the second step to obtain a fired product with NH ３ and a third step of performing a heat treatment under the above-mentioned conditions.

20. The method according to claim 19, wherein in the first step, the first compound and the second compound are mixed in the presence of nitric acid.

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