Catalyst composition, method for promoting catalytic activity, method for producing catalyst composition, and method for synthesizing ammonia using catalyst composition

Abstract

Provided is a catalyst composition that is capable of improving catalyst performance by having a catalyst additive added thereto. The catalyst composition is characterized by comprising: a catalyst additive represented by formula (1) LmAn; and a chemical reaction catalyst that includes a catalyst substance represented by formula (2) MpOqCwNsHt. (In formula (1), L represents at least one selected from the group consisting of transition elements and Al, A represents at least one selected from the group consisting of Si, O, N, and C, m represents a numerical value of 1 or more, and n represents a numerical value of 0 or more. In formula (2), M represents one or more selected from the group consisting of typical elements and transition elements, M does not include Al and Ca at the same time, p represents a numerical value of 0 or more, q represents a numerical value of 0 or more, w represents a numerical value of 0 or more, s represents a numerical value of 0 or more, and t represents a numerical value of 0 or more. q, w, s, and t are not 0 at the same time.

Description

[Technical Field]

[0001] The present invention relates to a catalyst composition, a method for promoting catalyst activity, a method for producing a catalyst composition, and a method for synthesizing ammonia using the catalyst composition. This application claims priority based on Japanese Patent Application No. 2021-182700, filed on November 9, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Catalysts are often used to promote chemical reactions. One example of such a chemical reaction is the ammonia synthesis reaction, which is a hydrogenation reaction. For example, a typical ammonia synthesis method is the Haber-Bosch process. The Haber-Bosch process uses a doubly promoted iron catalyst containing Fe3O4 with a few mass percent of Al2O3 and K2O, and produces ammonia by directly reacting a gas mixture of nitrogen and hydrogen with this catalyst under high temperature and pressure conditions. This technology is still used industrially today, with the manufacturing process remaining almost unchanged since its initial development.

[0003] Meanwhile, methods for synthesizing ammonia at temperatures lower than the reaction temperature of the Haber-Bosch process have been investigated. Catalysts capable of synthesizing ammonia by contacting nitrogen and hydrogen have been investigated, and transition metals have been considered as catalytically active components. Among these, a method using ruthenium (Ru) as the catalytically active component supported on various supports as a catalyst for ammonia synthesis has been proposed as an efficient method (see, for example, Patent Document 1).

[0004] There is a compound called a "Mayenite type compound," which is a calcium aluminosilicate composed of CaO, Al2O3, and SiO2 and has the same crystal structure as mayenite. The representative composition of the mayenite type compound is expressed as 12CaO 7Al2O3, and it has a structure in which two oxygen atoms are enclosed as "free oxygen" in the space within the cage formed by the crystalline skeleton. The present inventors have found that a catalyst in which a transition metal is supported as a catalytically active component on a mayenite compound (hereinafter referred to as C12A7 electride) in which free oxygen in the mayenite compound is substituted with electrons has high activity as a catalyst for ammonia synthesis (Patent Document 2). Furthermore, the present inventors have found that supported metal catalysts using metal amide compounds, metal hydrides, main group element oxides, metal hydrides, alkaline earth metal oxides, etc. have high activity as ammonia synthesis catalysts (Patent Documents 3 to 6). Also, a supported metal catalyst using a composite oxide has been disclosed as an ammonia synthesis catalyst (Patent Document 7). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-231229 [Patent Document 2] International Publication No. 2012 / 077658 [Patent Document 3] International Publication No. 2016 / 088896 [Patent Document 4] International Publication No. 2017 / 082265 [Patent Document 5] Japanese Patent Application Publication No. 2019-126776 [Patent Document 6] International Publication No. 2021 / 172107 [Patent Document 7] International Publication No. 2019 / 59190 Summary of the Invention [Problem to be solved by the invention]

[0006] Ammonia synthesis using the Haber-Bosch process, which mainly uses a doubly promoted iron catalyst, has been put to practical use, but it requires high temperature and pressure conditions, which poses problems in terms of equipment and cost. The supported metal catalysts described in Patent Document 1 typically use a carbonaceous support such as activated carbon or an inorganic oxide support. However, these supported metal catalysts do not always have sufficient performance for practical use. Furthermore, the supported metal catalysts described in Patent Documents 2 to 6 do not necessarily have fully satisfactory catalytic activity depending on the case and conditions. In other words, there is a demand for ammonia synthesis catalysts with superior catalytic activity, such as those that maintain sufficient reaction activity even under lower temperature and pressure conditions than those used in the Haber-Bosch process. [Means for solving the problem]

[0007] The present inventors have discovered that the catalytic performance of the catalyst composition of the present invention can be improved by adding a catalyst additive, and have arrived at the present invention.

[0008] That is, the gist of the present invention is [1] A catalyst additive represented by the following formula (1): A chemical reaction catalyst containing a catalytic substance represented by the following formula (2); A catalyst composition comprising: L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. M p O q C w N s H t (2) (In formula (2), M represents one or more elements selected from the group consisting of main group elements and transition elements, provided that M does not contain aluminum (Al) and calcium (Ca) at the same time; p represents a number greater than or equal to 1, q represents a number greater than or equal to 0, w represents a number greater than or equal to 0, s represents a number greater than or equal to 0, and t represents a number greater than or equal to 0. However, q, w, s, and t are not all 0 at the same time. [2] The chemical reaction catalyst and the catalyst composition have hydrogenation reaction activity, The catalyst composition according to [1], wherein the hydrogenation reaction activity of the catalyst composition exceeds the hydrogenation reaction activity of the chemical reaction catalyst. [3] The catalyst composition according to [2], wherein the hydrogenation reaction activity of the chemical reaction catalyst and the catalyst composition is ammonia synthesis activity. [4] The catalyst composition according to [2] or [3], wherein the catalyst additive does not have hydrogenation reaction activity. [5] The catalyst composition according to any one of [1] to [4], wherein in the formula (1), L is at least one selected from the group consisting of titanium (Ti), iron (Fe), nickel (Ni) and aluminum (Al). [6] The catalyst composition according to [5], wherein in the formula (1), L is titanium (Ti). [7] The catalyst composition according to any one of [1] to [5], wherein the catalyst additive is at least one selected from the group consisting of Fe, Ni, Al, Ti, TiSi, TiO, TiN, and TiC. [8] In the formula (2), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), lanthanum (La), silicon (Si), and aluminum (Al); The catalyst composition according to any one of [1] to [7], wherein p is a numerical value of 1 or more, q is a numerical value of 1 or more, w is a numerical value of 0 or more, s is a numerical value of 0 or more, and t is a numerical value of 0 or more. [9] In the formula (2), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La); The catalyst composition according to any one of [1] to [7], wherein p is a numerical value of 1 or more, q is a numerical value of 1 or more, w is 0, s is 0, and t is 0.

[10] The catalyst composition according to any one of [1] to [9], wherein the catalyst substance represented by the formula (2) is a catalyst substance represented by the following formula (2-1): M p O q (2-1) (In formula (2-1), M, p, q, w, s, and t have the same meanings as M, p, q, w, s, and t in formula (2).)

[11] The catalyst composition according to any one of [1] to

[11] , wherein the catalyst material is one selected from the group consisting of Ba—MgO, Sr—MgO, BaAl2O4, CeO2, and Ba—CeO2.

[12] The chemical reaction catalyst further comprises a catalytically active metal; the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, The catalyst composition according to any one of [1] to

[11] , wherein the support is the catalyst material represented by the formula (2).

[13] The catalyst composition according to

[12] , wherein the catalytically active metal is at least one selected from the group consisting of ruthenium (Ru), cobalt (Co), iron (Fe), nickel (Ni), molybdenum (Mo), rhodium (Rh), rhenium (Re), chromium (Cr), and manganese (Mn).

[14] The catalyst composition according to

[12] or

[13] , wherein the support does not simultaneously contain silicon (Si), oxygen (O), and aluminum (Al).

[15] The catalyst composition according to any one of

[12] to

[14] , wherein the support is a basic metal oxide.

[16] The catalyst composition according to

[15] , wherein the support is a crystalline basic metal oxide.

[17] In the formula (1), L is titanium (Ti), In the formula (2), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La); p represents a number greater than or equal to 1, q represents a number greater than or equal to 1, The chemical reaction catalyst further comprises a catalytically active metal; the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, The support is the catalytic material represented by formula (2), The catalytically active metal is at least one selected from the group consisting of ruthenium (Ru), cobalt (Co), and iron (Fe). The catalyst composition according to any one of [1] to [4].

[18] The catalyst additive is at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC; The catalytic material is one selected from the group consisting of Ba—MgO, Sr—MgO, BaAl2O4, CeO2, and Ba—CeO2. The chemical reaction catalyst further comprises a catalytically active metal; the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, the support is the catalytic material; The catalyst composition according to any one of [1] to [4], wherein the catalytically active metal is one selected from the group consisting of Ru, Co, and Fe.

[19] A method for promoting catalytic activity, comprising the step of adding or mixing a catalyst additive to a chemical reaction catalyst or a precursor thereof, thereby promoting the electron donating ability of the chemical reaction catalyst and promoting catalytic activity, The method includes a step of adding or mixing the catalyst additive with a chemical reaction catalyst or a precursor thereof, and reacting the resulting mixture at a temperature of less than 700°C in the presence of a reducing gas or an inert gas; The catalyst additive is a catalyst additive represented by the following formula (1): The method for promoting catalytic activity is characterized in that the chemical reaction catalyst is a chemical reaction catalyst containing a catalytic substance represented by the following formula (2): L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. M p O q C w N s H t (2) (In formula (2), M represents one or more elements selected from the group consisting of main group elements and transition elements; p represents a number greater than or equal to 1, q represents a number greater than or equal to 0, w represents a number greater than or equal to 0, s represents a number greater than or equal to 0, and t represents a number greater than or equal to 0. However, q, w, s, and t are not all 0 at the same time.

[20] The method for promoting catalytic activity according to

[19] , wherein the temperature condition is 600°C or less.

[21] The chemical reaction catalyst further comprises a catalytically active metal; the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, The method for promoting catalytic activity according to

[19] or

[20] , wherein the support is the catalytic material represented by the formula (2).

[22] The method for promoting catalytic activity according to any one of

[19] to

[21] , wherein the catalytic activity is hydrogenation reaction activity.

[23] The method for promoting catalytic activity according to

[22] , wherein the hydrogenation reaction activity is ammonia synthesis activity.

[24] The method for promoting catalytic activity according to any one of

[19] to

[23] , wherein the catalyst additive has no hydrogenation reaction activity.

[25] A method for producing a catalyst composition according to any one of [1] to

[18] , a first step of mixing the catalyst additive with the chemical reaction catalyst or a precursor thereof; a second step of reacting the first mixture obtained in the first step at a temperature of less than 700°C in the presence of a reducing gas or an inert gas; A method for producing a catalyst composition, comprising:

[26] a catalyst additive; a chemical reaction catalyst or a precursor thereof; a first step of mixing the above; a second step of reacting the first mixture obtained in the first step at a temperature of less than 700°C in the presence of a reducing gas or an inert gas; A method for producing a catalyst composition, comprising: The catalyst additive is a catalyst additive represented by the following formula (1): The method for producing a catalyst composition, wherein the chemical reaction catalyst is a chemical reaction catalyst containing a catalytic substance represented by the following formula (2): L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. M p O q C w N s H t (2) (In formula (2), M represents one or more elements selected from the group consisting of main group elements and transition elements; p represents a number greater than or equal to 1, q represents a number greater than or equal to 0, w represents a number greater than or equal to 0, s represents a number greater than or equal to 0, and t represents a number greater than or equal to 0. However, q, w, s, and t are not all 0 at the same time.

[27] The method for producing a catalyst composition according to

[25] or

[26] , wherein the temperature condition is 600°C or less.

[28] The method for producing a catalyst composition according to any one of

[25] to

[27] , further comprising a third step of obtaining the catalyst composition using the second mixture obtained in the second step without removing the catalyst additive contained in the second mixture.

[29] The method for producing a catalyst composition according to any one of

[25] to

[28] , further comprising a third step of removing the catalyst additive contained in the second mixture using the second mixture obtained in the second step.

[30] A catalyst composition obtained by using the method for producing a catalyst composition according to any one of

[26] to

[29] .

[31] A method for producing a hydrogenated product, comprising a step of reacting a raw material compound to be hydrogenated with hydrogen in the presence of the catalyst composition according to any one of [1] to

[18] and

[30] .

[32] A method for producing ammonia, comprising a step of reacting nitrogen with hydrogen in the presence of the catalyst composition according to any one of [1] to

[18] and

[30] .

[33] Use of a catalyst additive represented by the following formula (1) for a reaction in which a mixture obtained by adding or mixing a chemical reaction catalyst or its precursor thereto is added to or mixed with a chemical reaction catalyst or its precursor, thereby promoting catalytic activity by promoting the electron donating ability of the chemical reaction catalyst, and the reaction is carried out at a temperature of less than 700°C in the presence of a reducing gas or an inert gas. L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. [Effects of the Invention]

[0009] The catalytic performance of the catalyst composition of the present invention can be improved by adding a catalyst additive. Furthermore, when the catalyst composition of one embodiment of the present invention is used as a hydrogenation catalyst, particularly as an ammonia synthesis catalyst, it exhibits high ammonia synthesis activity. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the dependence of the catalytic activity (ammonia synthesis rate) of the catalyst compositions (ammonia synthesis catalysts) of Examples 1 to 5 and Comparative Example 1 on the amount of TiSi added (upper reaction conditions (▲): 400°C, 0.9 MPa; lower reaction conditions (△): 340°C, 0.9 MPa). [Figure 2] FIG. 1 is a graph showing the catalytic activity (ammonia synthesis rate) of catalyst compositions (ammonia synthesis catalysts) in Examples 1 and 6 and Comparative Example 1. Catalytic activity (reaction conditions: 400° C., 0.9 MPa). [Figure 3] FIG. 1 is a graph showing the catalytic activity (ammonia synthesis rate) of catalyst compositions (ammonia synthesis catalysts) in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. [Figure 4] FIG. 1 is a graph showing the catalytic activity (ammonia synthesis rate) of catalyst compositions (ammonia synthesis catalysts) in Examples 1 and 7 to 11 and Comparative Examples 1, 2 and 4 to 7. [Figure 5] FIG. 1 is a graph showing the catalytic activity (ammonia synthesis rate) of the catalyst compositions (ammonia synthesis catalysts) of Example 1, Examples 12 to 19, and Comparative Example 1 (reaction conditions: 400° C., 0.9 MPa). [Figure 6] FIG. 1 is a graph showing the catalytic activity (ammonia synthesis rate) of the catalyst compositions (ammonia synthesis catalysts) of Example 1, Examples 12 to 18, and Comparative Example 1 (reaction conditions: 340° C., 0.9 MPa). [Figure 7] 1 is a graph showing the change in catalytic activity (ammonia synthesis rate) over time in Example 1 (reaction conditions: 400° C., 0.9 MPa). DETAILED DESCRIPTION OF THE INVENTION

[0011] (Terminology) In the present invention, "hydrogenation reaction activity" means having catalytic activity for a hydrogenation reaction. Furthermore, "catalyst having hydrogenation reaction activity" and "hydrogenation reaction catalyst" mean a catalyst having catalytic activity for a hydrogenation reaction. Hydrogenation is a reduction reaction in which hydrogen atoms are added to a compound using hydrogen gas as a reducing agent. The "hydrogenation reaction" of the present invention is particularly a hydrogenation reaction that uses a catalyst, and is also called "catalytic hydrogenation."

[0012] In the present invention, "ammonia synthesis activity" means having catalytic activity for an ammonia synthesis reaction, which is a specific example of a hydrogenation reaction. Furthermore, "a catalyst having ammonia synthesis activity" and "ammonia synthesis catalyst" mean a catalyst having catalytic activity for an ammonia synthesis reaction.

[0013] In the present invention, the phrase "the hydrogenation reaction activity of catalyst A exceeds the hydrogenation reaction activity of catalyst B" means that, when the reaction conditions other than the type of catalyst are the same, catalyst A exceeds catalyst B in terms of the hydrogenation reaction rate.

[0014] In the present invention, the term "catalytically active metal" refers to a metal having catalytic activity for a certain chemical reaction. For example, when the chemical reaction is a hydrogenation reaction such as an ammonia synthesis reaction, the catalytically active metal is a metal having a hydrogenation reaction activity such as ammonia synthesis activity for the hydrogenation reaction such as an ammonia synthesis reaction.

[0015] In the present invention, the term "precursor of a chemical reaction catalyst" refers to a raw material or intermediate product for producing a chemical reaction catalyst. When the raw material or intermediate product contains two compounds, the precursor of the chemical reaction catalyst may be a mixture. For example, in the specific example of Example 1, the raw material mixture consisting of "MgO + Ba(NO3)2 + Ru(NO)(NO3)3" is a precursor of the chemical reaction catalyst Ru / Ba-MgO.

[0016] (Catalyst composition) The catalyst composition of the present embodiment contains a catalyst additive represented by the following formula (1) and a chemical reaction catalyst containing a catalytic substance represented by the following formula (2). L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. M p O q C w N s H t (2) (In formula (2), M represents one or more elements selected from the group consisting of main group elements and transition elements, provided that M does not contain aluminum (Al) and calcium (Ca) at the same time; p represents a number greater than or equal to 1, q represents a number greater than or equal to 0, w represents a number greater than or equal to 0, s represents a number greater than or equal to 0, and t represents a number greater than or equal to 0. However, q, w, s, and t are not all 0 at the same time. The catalyst composition is not particularly limited, but examples thereof include the catalyst composition of the first embodiment and the catalyst composition of the second embodiment described below.

[0017] First Embodiment The catalyst composition and the chemical reaction catalyst of this embodiment have hydrogenation reaction activity, that is, the catalyst composition and the chemical reaction catalyst of this embodiment are hydrogenation reaction catalysts. The hydrogenation reaction activity of the catalyst composition preferably exceeds the hydrogenation reaction activity of the chemical reaction catalyst.

[0018] The hydrogenation reaction activity of the catalyst composition and chemical reaction catalyst of this embodiment is preferably ammonia synthesis activity.

[0019] The catalyst additive contained in the catalyst composition of this embodiment may or may not have hydrogenation reaction activity.

[0020] [Catalyst Additives] In the catalyst additive according to this embodiment, the transition element used for L in formula (1) is not particularly limited, but is usually a transition element of Group 3, 4, 5, 6, 7, 8, 9, 10 or 11 of the periodic table, preferably a transition element of Group 4, 8 or 10, more preferably a Group 4 element. In the catalyst additive according to this embodiment, in the formula (1), L is preferably at least one selected from the group consisting of titanium (Ti), iron (Fe), nickel (Ni) and aluminum (Al), and L is more preferably titanium (Ti). The catalyst additive is preferably at least one selected from the group consisting of Fe, Ni, Al, Ti, TiSi, TiO, TiN, and TiC. The catalyst additive is more preferably at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC. The catalyst additive is even more preferably Ti.

[0021] Titanium silicide is an alloy of titanium and silicon. Its internal structure is a composite of TiSi and TiSi2. Unless otherwise specified, titanium silicide is simply referred to as TiSi. Titanium silicide may also be referred to as TiSix. In the present invention, unless otherwise specified, "TiSi" and "TiSix" are used interchangeably.

[0022] The catalyst additive according to this embodiment may not have hydrogenation reaction activity, and the catalyst additive according to this embodiment may not have ammonia synthesis activity. Examples of catalyst additives that do not have ammonia synthesis activity include Al, Ti, TiSi, TiO, TiN, and TiC.

[0023] The catalyst additive according to this embodiment may have hydrogenation reaction activity, and may also have ammonia synthesis activity. Examples of catalyst additives having ammonia synthesis activity include Fe and Ni. When a catalyst additive having ammonia synthesis activity is added, it is preferable that the chemical reaction catalyst described below does not contain a substance similar to this catalyst additive. For example, when the catalyst additive is Fe, it is preferable that the chemical reaction catalyst does not contain Fe.

[0024] The amount of catalyst additive added according to this embodiment is the content of the catalyst additive relative to 100% by mass of the final catalyst composition. It is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 20% by mass or more. It is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45.0% by mass or less.

[0025] This embodiment includes the use of a catalyst additive represented by the following formula (1) for a reaction that promotes catalytic activity by promoting the electron donating ability of a chemical reaction catalyst, and that is carried out at a temperature of less than 700°C in the presence of a reducing gas or an inert gas by adding or mixing the catalyst additive to or with a chemical reaction catalyst or its precursor. L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. In the above embodiment, the use of the above catalyst additive for the above catalytic activity promoting reaction can improve the catalytic performance of the catalyst composition of the present invention, which is expected to prevent a decrease in the stability of the chemical reaction catalyst contained in the catalyst composition of the present invention and reduce the load on the reactor due to high-temperature hydrogen treatment.

[0026] [Chemical reaction catalyst] The chemical reaction catalyst according to the first embodiment further contains a catalytically active metal. That is, the chemical reaction catalyst according to the present embodiment is a metal-supported material in which the catalytically active metal is supported on a support. The support is the catalytic material represented by the formula (2).

[0027] <<Catalytic active metal>> The catalytically active metal according to this embodiment is preferably a transition metal. The transition metal used in this embodiment is not particularly limited, but is usually a transition metal of Group 6, 7, 8, 9 or 10 of the periodic table, preferably a transition metal of Group 6, 8 or 9, more preferably a metal of Group 8 or 9.

[0028] The catalytically active metal according to this embodiment is preferably at least one selected from the group consisting of ruthenium (Ru), cobalt (Co), iron (Fe), nickel (Ni), molybdenum (Mo), rhodium (Rh), rhenium (Re), chromium (Cr), and manganese (Mn). The catalytically active metal according to this embodiment is more preferably at least one selected from the group consisting of ruthenium (Ru), cobalt (Co), iron (Fe), and nickel (Ni). The catalytically active metal according to this embodiment is even more preferably ruthenium (Ru).

[0029] The above elements may be used alone or in combination of two or more. Intermetallic compounds of these elements, such as Co3Mo3N, Fe3Mo3N, Ni2Mo3N, and Mo2N, may also be used. Preferably, each element is used alone or in combination of two or more, and more preferably, each element is used alone, which is advantageous in terms of cost.

[0030] <<Catalytic material (support)>> The catalyst material (support) according to this embodiment is represented by the formula (2), wherein M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), lanthanum (La), silicon (Si), and aluminum (Al); It is preferred that p is a number of 1 or more, q is a number of 1 or more, w is a number of 0 or more, s is a number of 0 or more, and t is a number of 0 or more.

[0031] In the catalyst material (support) according to this embodiment, in the formula (2), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La), p is a numerical value of 1 or more, q is a numerical value of 1 or more, w is 0, s is 0, and t is 0.

[0032] The catalyst material (support) according to this embodiment is preferably a basic metal oxide, and more preferably a basic metal oxide having crystallinity. Examples of basic metal oxides include BaO, SrO, MgO, CaO, CeO2, La2O3, Y2O3, and BaAl2O4.

[0033] The catalyst material (support) according to this embodiment is more preferably a catalyst material represented by the following formula (2-1).

[0034] M p O q (2-1)

[0035] In formula (2-1), M represents one or more elements selected from the group consisting of typical elements and transition elements, provided that M does not contain aluminum (Al) and calcium (Ca) at the same time. It is also preferred that p represents a value greater than 0, q represents a value greater than 0, w represents a value greater than 0, s represents a value greater than 0, and t represents a value greater than 0.

[0036] "Compound of formula (2-1)" The compound of the above formula (2-1) may be a main group element oxide represented by the following general formula (2-1a). A n B m O l (2-1a)

[0037] In the general formula (2-1a), A is at least one selected from the group consisting of Ba and Sr, B is at least one selected from the group consisting of Al, Ga, In, Si, Ge and Sn, n is an integer of 1 to 17, m is an integer of 1 to 17, and l is a number represented by an integer of 1 to 26. It is preferable that l is 4 or 5.

[0038] In this embodiment, the term "typical element" refers to an element in Groups 1, 2, and 12 to 18 of the periodic table. This does not include transition elements (elements in Groups 3 to 11) of the periodic table. The "typical element oxide" or "typical element composite oxide" of the present invention preferably contains 90% by mass or more of an oxide or composite oxide composed of a typical element (elements in Groups 1, 2, and 12 to 18 of the periodic table) excluding oxygen and oxygen. More preferably, it contains 95% by mass or more, 99% by mass or more, or essentially 100% by mass. Still more preferably, it contains essentially 100% by mass. "Containing essentially 100% by mass" means, for example, that the transition element content is less than 1% by mass or less than 0.5% by mass. The support of the metal-supported material of the present invention preferably contains 50% by mass or more of the typical element oxide or "typical element composite oxide" of the present invention. It more preferably contains 70% by mass or more. It is even more preferably contains 90% by mass or more. It is particularly preferably contains substantially 100% by mass or more. "Contains substantially 100% by mass" means, for example, that the content of the transition element oxide in terms of transition element is less than 1% by mass, or less than 0.5% by mass.

[0039] Specific examples of the typical element oxides of this embodiment include BaAl2O4, Ba3Al2O6, Ba4Al2O7, Ba 17Al3O7, BaAl4O7, BaAl 12 O 19 , BaGa2O4, BaGa4O7, Ba4Ga2O7, Ba3Ga2O6, BaInO 2.5 , Ba3In2O6, Ba8In6O 17 , Ba2In2O5, Ba4In2O7, Ba4In6O 13 , SrAl2O4, SrAl 12 O 19 , SrAl4O7, Sr4Al 14 O 25 , Sr9Al6O 18 , Sr3Al2O6, Sr 10 AlO 19 , SrAlO 11 , Sr7Al 12 O 25 , SrGa2O4, Sr3Ga4O9, SrGa 12 O 19 , Sr 10 GaO 19 , Sr3Ga2O6, Sr4Ga2O7, Sr2Ga2O5, Sr5Ga6O 14 , SrGa4O7, Ba3SiO5, Ba2SiO4, Ba2Si4O 10 , Ba4Si6O 16 , BaSi4O9, Ba5Si8O 21 , Ba6Si 10 O 26 , BaSiO3, BaSi2O5, Ba3GeO, BaGe4O9, BaGe2O5, Ba 10 Ge7O3, BaGeO3, Ba3Ge3O9, Sr3SiO5, Sr3Si3O9, Sr4Si4O 12 , Sr2SiO4, SrSiO3, SrSi2O5, Sr3SiO, Sr3GeO, Sr2GeO4, SrGeO3, SrGe4O9, SrGe2O5, etc. Among these, from the viewpoints of availability, ease of preparation, versatility, etc., BaAl2O4, Ba2SiO4, and Ba3SiO5 are preferred, and BaAl2O4 is more preferred.

[0040] [Method of manufacturing main group element oxides] The synthesis examples of BaAl2O4 and Ba2SiO4 will be used for explanation. <Synthesis of BaAl2O4> 0.148 g of barium carbonate (Wako Pure Chemical Industries, 99.9%) and 0.117 g of aluminum hydroxide (High purity chemicals, 99.99%) are mixed so that the molar ratio is 1:2, and the obtained mixture is placed in an alumina crucible, heated to 1000 °C over 3 hours, and maintained for 10 hours to obtain BaAl2O4.

[0041] <Synthesis of Ba2SiO4> Ba(CH3COO)2 (Kanto Chemical, 9.0%) and TEOS (tetraethyl orthosilicate) are reacted by a complex polymerization method using ethylene glycol (Kanto Chemical and Wako Pure Chemical Industries, 99.0%) in which citric acid (Kanto Chemical, 99.0%) is previously dissolved as a solvent. The obtained reactant (Ba2SiO4 raw material) is prepared in a stoichiometric amount, and this is placed in a beaker together with a stir bar using ethylene glycol in which citric acid is previously dissolved as a solvent, and stirred overnight at 120 °C. Then, the temperature is raised to 180 °C and held for 6 h to obtain a brown gel-like substance. Thereafter, the obtained gel-like substance is transferred to a mantle heater together with the beaker and held at 450 °C for 2 h to obtain a black powder. The obtained black powder is placed in an alumina crucible, heated to 800 °C over 40 min using an electric furnace, and held at 800 °C for 4 h to obtain the target white powder Ba2SiO4.

[0042] <Group 13 typical element oxides> The typical element oxide according to this embodiment may be a composite oxide of a typical element represented by the following general formula (2-1b). AB2O l (2-1b) (In the general formula (2-1b), B is at least one selected from the group consisting of Al, Ga, and In, l represents a number represented by 3.5 ≦ l ≦ 4.5, and A has the same meaning as A in the general formula (1).)

[0043] The compound represented by the general formula (2-1b) is a compound represented by the general formula (2-1a) in which n is 1, m is 2, l is a number satisfying 3.5≦l≦4.5, and B is at least one selected from the group consisting of Al, Ga, and In.

[0044] In the general formula (2), l preferably represents a number expressed by 3.8≦l≦4.2, more preferably a number expressed by 3.9≦l≦4.1, and more preferably l is 4. For example, BaAl2O4, either commercially available or prepared by the methods described herein, can be used.

[0045] <Main group element oxides containing Group 14 elements> The typical element oxide of this embodiment is a typical element oxide represented by the following general formula (2-1c). A2BO l (2-1c) (In the general formula (3), B is at least one selected from the group consisting of Si, Ge, and Sn, l represents a number satisfying the formula 3.5≦l≦4.5, and A has the same meaning as A in the general formula (2-1a).)

[0046] The compound represented by the general formula (2-1c) is a compound represented by the general formula (2-1a) in which n is 2, m is 1, l is a number satisfying 3.5≦l≦4.5, and B is at least one selected from the group consisting of Si, Ge, and Sn.

[0047] In the general formula (2-1c), l preferably represents a number expressed by 3.8≦l≦4.2, more preferably a number expressed by 3.9≦l≦4.1, and more preferably l is 4.

[0048] The compound of the above formula (2-1) may be a composite oxide represented by the following general formula (2-1d). A n X yM m O x (2-1d) (In the general formula (2-1d), A is a rare earth element characterized in that at least a part or all of it is in a trivalent state, X represents any one of Group 2 elements, Group 4 elements, and rare earth elements of the periodic table, and is different from A; M represents an element selected from Group 2, Group 4, and rare earth elements of the periodic table, and is different from A and X; n is 0 <n<1であり、 y is 1-n, m is 0≦m≦0.5, x represents the number of oxygen atoms required for the composite oxide to maintain electrical neutrality.

[0049] Such element A can include lanthanoids, preferably Ce, Pr, Tb, and La. Ce and La are more preferred, and Ce is most preferred. The element X constituting the composite oxide of general formula (2-1d) is selected from, for example, Group 2 elements of the periodic table such as Mg, Ca, Sr, Ba, etc., Group 4 elements such as Ti, Zr, Hf, etc., or rare earth elements such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc., and is not the same as the other element A constituting the composite oxide, and X and M are not the same. When element M is a Group 2 element of the periodic table, it is preferably selected from Ca, Sr, and Ba. When element M is a rare earth, it is preferably a lanthanide.

[0050] Element M that constitutes the composite oxide of general formula (2-1d) is selected from, for example, Group 1 elements of the periodic table such as Na, K, Rb, Cs, Fr, Group 2 elements of the periodic table such as Mg, Ca, Sr, Ba, Group 4 elements such as Ti, Zr, or Hf, or rare earth elements such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu, and is not the same as another element A that constitutes the composite oxide, and X and M are not the same. When element X is a Group 2 element of the periodic table, it is preferably selected from Ca, Sr, and Ba. When element X is a rare earth, it is preferably a lanthanoid. Particularly, from the viewpoint of ammonia synthesis activity, element M is preferably Ba.

[0051] Preferably, X and M are selected from Zr and La. The composite oxide in the present invention may contain two Group 4 elements or rare earth elements of the periodic table as X and M, or may contain only one Group 4 element or rare earth element of the periodic table as X (m = 0 in general formula (2-1d)).

[0052] When the composite oxide of the present invention is represented by general formula (2-1d), the ranges of n, y, m, and x are as follows. In general formula (2-1d) representing the proportion of element A in the composite oxide, n satisfies 0 < n < 1, preferably 0.05 < n < 0.95, more preferably 0.1 < n < 0.9, and particularly preferably 0.35 ≤ n ≤ 0.5. In general formula (2-1d) representing the proportion of element X in the composite oxide, y satisfies 0 < y < 1, preferably 0.05 < y < 0.95, more preferably 0.1 < y < 0.9, and particularly preferably 0.35 ≤ y ≤ 0.5.

[0053] In general formula (2-1d) representing the proportion of element M in the composite oxide, m satisfies 0 ≤ m < 1, in general formula (2), m satisfies 0 ≤ m ≤ 0.5, and in both formulas (1) and (2), preferably 0 < m < 0.5, more preferably 0.05 ≤ m ≤ 0.45, and particularly preferably 0.1 ≤ m ≤ 0.3. When m = 0, the composite oxide is composed of only A, X, and O.

[0054] For example, La 0.5 Ce 0.5 O 1.75 In the case of a binary support containing two metal elements, such as those shown in Figure 1, when these elements are a complex of lanthanide elements, a uniform solid solution often forms. Ru particles then come into direct contact with the surface. When Ce is reduced, since both La and Ce are strongly basic elements in the oxide state, it is presumed that there are many active sites with Ru, resulting in high ammonia synthesis activity.

[0055] On the other hand, for example, Ba 0.1 La 0.45 Ce 0.45 O x In the case of a ternary support containing three metal elements, as shown in Figure 1, Ba has a larger atomic radius than La and Ce. In this case, if the calcination temperature of the raw material mixture is high, for example, above 1000°C, all elements are uniformly dissolved, resulting in a perovskite-type crystal structure. On the other hand, if the calcination temperature of the raw material mixture is low, Ba is a large element and does not easily dissolve with other elements. Therefore, a structure is formed in which Ba is unevenly mixed in the solid solution of La and Ce, and some of the Ba is exposed on the surface of the solid solution of La and Ce. Because Ba is a strongly basic element with a higher partial negative charge on oxygen than La and Ce, a support with unevenly exposed Ba has a larger contact area between Ba and Ru, increasing the number of active sites. This is presumably why the ammonia synthesis activity is higher.

[0056] Specific examples of the composite oxide of this embodiment include the following. Ce 0.5 La 0.5 O x Pr 0.5 La 0.5 O x Ba 0.3 Pr 0.35 Ce 0.35 O x Ba 0.1 La 0.45 Ce0.45 O x

[0057] <Metal oxide / metal support manufacturing method> The composite oxide of this embodiment can be produced by the following method. (a) a mixing step of mixing an A precursor containing an element A, an X precursor containing an element X, and an M precursor containing an element M to obtain a mixture; (b) a calcination step of calcining the mixture. The above specific example of the composite oxide of this embodiment can be synthesized by the same method as disclosed in the examples of Patent Document 7.

[0058] Examples of the catalyst material (support) according to this embodiment include Ba—MgO, Sr—MgO, BaAl2O4, CeO2, and Ba—CeO2. Among these, Ba—MgO, BaAl2O4, CeO2, and Ba—CeO2 are preferred. It is preferable that the catalyst material (support) according to this embodiment does not contain silicon (Si), oxygen (O), and aluminum (Al) simultaneously.

[0059] <<Metal carriers>> The metal-supported material of this embodiment is obtained by supporting a transition metal (M) on the above-mentioned catalytic substance (support). The transition metal (M) is preferably at least one selected from the group consisting of Ru, Co, and Fe.

[0060] The amount of the transition metal supported is not particularly limited, but is usually 0.01 parts by mass (0.01% by mass) or more, preferably 0.5 parts by mass (0.5% by mass) or more, more preferably 1 part by mass (1% by mass) or more, and even more preferably 2 parts by mass (2% by mass) or more, relative to 100 parts by mass of the support, and is usually 50 parts by mass (50% by mass) or less, preferably 30 parts by mass (30% by mass) or less, more preferably 20 parts by mass (20% by mass) or less, and even more preferably 10 parts by mass (10% by mass) or less. If the amount is equal to or greater than the lower limit, the effects of the present invention can be obtained, and if the amount is equal to or less than the upper limit, the effects of the present invention can be obtained in a manner that balances the supported amount and cost.

[0061] <Method for supporting transition metal (M) on metal support> The method for supporting a transition metal (M) on a metal support is not particularly limited, but for example, a support in which a transition metal (M) is fixed to a catalytic substance (support) can be obtained by the following method. The above method includes, for example, a step of dispersing the catalytic substance (support) and a precursor of the metal to be supported in an aqueous solution and stirring the mixture; a step of drying the mixture after stirring at 140°C for about 2 hours; and a step of heating the dried mixture at 400°C for 4 hours in a nitrogen atmosphere to thermally decompose the metal compound.

[0062] For example, transition metal compounds in which the transition metal (M) is Ru, Co, or Fe include nitrates, formates, and carbonyl complexes. Specific examples include Ru(NO)(NO3)3 and Co(NO3). 2、 Using Fe(NO3)3, metal supports such as Ru support (abbreviated as Ru / support) and Co support (abbreviated as Co / support) were prepared. 、 Fe-supported materials (abbreviated as Fe / support) can be synthesized.

[0063] <Shape of metal carrier> The shape of the metal support of this embodiment is not particularly limited, and specifically may be any shape such as a block, powder, film, etc., but is usually powder. The particle size of the powdered metal support is not particularly limited, but is usually 1 nm or more and 10 μm or less. The particle size of the transition metal in the metal-supported material of this embodiment is not particularly limited, but is usually 1 nm or more and 100 nm or less, preferably 20 nm or less, more preferably 10 nm or less, which is advantageous in that the number of step sites, which are active sites for nitrogen dissociation, increases when the material is used as a catalyst for ammonia synthesis.

[0064] The catalyst composition of this embodiment includes: The catalyst additive according to the present embodiment is at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC, The catalyst material according to this embodiment is one selected from the group consisting of Ba—MgO, Sr—MgO, BaAl2O4, CeO2, and Ba—CeO2. The chemical reaction catalyst according to this embodiment further contains a catalytically active metal, the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, the support is the catalytic material; The catalytically active metal is one selected from the group consisting of Ru, Co, and Fe.

[0065] Further, the catalyst composition of this embodiment may include: The catalyst additive according to the present embodiment is at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC, The catalyst material according to this embodiment is one selected from the group consisting of Ba—MgO, BaAl2O4, CeO2, and Ba—CeO2. The chemical reaction catalyst according to this embodiment further contains a catalytically active metal, the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, the support is the catalytic material; The catalytically active metal is one selected from the group consisting of Ru, Co, and Fe.

[0066] Second Embodiment The catalyst composition of this embodiment can use the same catalyst additive and catalyst substance as those described in the first embodiment. In the first embodiment, the various embodiments, preferred examples, production methods, etc. related to the catalyst additive and the catalyst substance are incorporated by reference in this embodiment. The catalyst composition of this embodiment differs from the catalyst composition of the first embodiment and the chemical reaction catalyst of the first embodiment. The chemical reaction catalyst of this embodiment differs from the chemical reaction catalyst of the first embodiment in that it does not contain a catalytically active metal. In addition, the chemical reaction catalyst of this embodiment is the same as the first embodiment except that it does not contain a catalytically active metal. That is, the chemical reaction catalyst of this embodiment includes a catalytic material that does not support a catalytically active metal. The catalytic material of this embodiment is the same as the catalytic material of the first embodiment. The chemical reaction catalyst according to this embodiment may further contain a substance that is not a catalytic substance (excluding catalytically active metals) as necessary. The chemical reaction catalyst according to this embodiment is preferably the catalytic substance according to this embodiment.

[0067] In the catalyst composition of the present embodiment, the catalyst additive according to the present embodiment is at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC, The catalyst material according to this embodiment is one selected from the group consisting of Ba—MgO, Sr—MgO, BaAl2O4, CeO2, and Ba—CeO2. The chemical reaction catalyst according to this embodiment may be an ammonia synthesis catalyst, which is a catalytic substance.

[0068] In addition, the catalyst composition of this embodiment is characterized in that the catalyst additive of this embodiment is at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC, and the catalyst substance of this embodiment is one selected from the group consisting of Ba—MgO, BaAl2O4, CeO2, and Ba—CeO2. The chemical reaction catalyst according to this embodiment may be an ammonia synthesis catalyst, which is the above-mentioned catalyst composition.

[0069] (Method for promoting catalyst activity) The method for promoting catalytic activity of the present embodiment includes a step of adding or mixing a catalytic additive to a chemical reaction catalyst or a precursor thereof, thereby promoting the electron donating ability of the chemical reaction catalyst and promoting catalytic activity. The method includes a step of adding or mixing the catalyst additive with a chemical reaction catalyst or a precursor thereof, and reacting the resulting mixture at a temperature of less than 700°C in the presence of a reducing gas or an inert gas; The catalyst additive is a catalyst additive represented by the following formula (1): The method for promoting catalytic activity is characterized in that the chemical reaction catalyst is a chemical reaction catalyst containing a catalytic substance represented by the following formula (2): L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. M p O q C w N s H t (2) (In formula (2), M represents one or more elements selected from the group consisting of main group elements and transition elements; p represents a number greater than or equal to 1, q represents a number greater than or equal to 0, w represents a number greater than or equal to 0, s represents a number greater than or equal to 0, and t represents a number greater than or equal to 0. However, q, w, s, and t are not all 0 at the same time.

[0070] The temperature condition is preferably 600° C. or less.

[0071] In the method for promoting catalytic activity of this embodiment, the chemical reaction catalyst may include a catalytic substance and a catalytically active metal. the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, The support is the catalytic material represented by the formula (2).

[0072] In the method for promoting catalytic activity of this embodiment, the chemical reaction catalyst does not need to contain a catalytically active metal.

[0073] In the method for promoting catalytic activity of this embodiment, the catalytic activity is preferably hydrogenation reaction activity, and more preferably ammonia synthesis activity.

[0074] In the method for promoting catalyst activity of this embodiment, the catalyst additive may or may not have hydrogenation reaction activity.

[0075] As preferred aspects and specific examples of the catalytic additive and chemical reaction catalyst according to this embodiment, the preferred aspects and specific examples described in the first and second embodiments of the catalyst composition can be cited.

[0076] (Method of producing catalyst composition) One embodiment of the production method of the present invention is a method for producing the above-mentioned catalyst composition. The production method of this embodiment includes a first step of mixing the catalyst additive and the chemical reaction catalyst or a precursor thereof; a second step of reacting the first mixture obtained in the first step at a temperature of less than 700°C in the presence of a reducing gas or an inert gas; Includes:

[0077] Another embodiment of the manufacturing method of the present invention includes a first step of mixing a catalyst additive with a chemical reaction catalyst or a precursor thereof; a second step of reacting the first mixture obtained in the first step at a temperature of less than 700°C in the presence of a reducing gas or an inert gas; Includes: The catalyst additive is a catalyst additive represented by the following formula (1): The chemical reaction catalyst is a chemical reaction catalyst containing a catalytic substance represented by the following formula (2): m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0. M p O q C w N s H t (2) (In formula (2), M represents one or more elements selected from the group consisting of main group elements and transition elements; p represents a number greater than or equal to 1, q represents a number greater than or equal to 0, w represents a number greater than or equal to 0, s represents a number greater than or equal to 0, and t represents a number greater than or equal to 0. However, q, w, s, and t are not all 0 at the same time.

[0078] The temperature condition is preferably 600° C. or less. The temperature condition may be 500° C. or less.

[0079] The production method of this embodiment may further include a third step of obtaining the catalyst composition using the second mixture obtained in the second step without removing the catalyst additive contained in the second mixture.

[0080] The production method of this embodiment may further include a third step of removing the catalytic additive contained in the second mixture obtained in the second step. Such a production method may contain a small amount of catalytic additive remaining after the treatment in the third step, or may not contain any catalytic additive after the treatment in the third step. Here, the "small amount" may be, for example, 1% to 5% by mass, 1% to 2.5% by mass, 1% to 2.0% by mass, or 1% to 1.5% by mass of the catalytic additive remaining after the treatment in the third step. Here, "not containing" means that the content (addition amount) of the catalyst additive is 0% or more and less than 1% by mass, 0% to 0.5% by mass, or 0% to 0.25% by mass, relative to 100% by mass of the catalyst composition.

[0081] Preferred aspects and specific examples of the catalyst additive and chemical reaction catalyst according to the production method of this embodiment can be derived from the preferred aspects and specific examples described in the first and second embodiments of the catalyst composition described above.

[0082] (Method for producing a compound using a catalyst composition as a catalyst) <Method for producing hydrides> The method for producing a hydrogenated product of this embodiment includes a step of reacting a raw material compound to be hydrogenated with hydrogen in the presence of the catalyst composition of this embodiment described above.

[0083] <Ammonia manufacturing method> The method for producing ammonia according to the present embodiment is characterized by comprising a step of reacting nitrogen with hydrogen in the presence of the catalyst composition according to the present embodiment. In this embodiment, the catalyst composition is an ammonia catalyst. The method for producing ammonia according to the present embodiment (hereinafter sometimes referred to as the production method of the present embodiment) is a method for synthesizing ammonia by using the catalyst for ammonia synthesis according to the present embodiment as a catalyst and reacting hydrogen and nitrogen on the catalyst. The specific production method is not particularly limited as long as it is a method in which hydrogen and nitrogen are brought into contact on the catalyst to synthesize ammonia, and ammonia can be produced in accordance with any known production method.

[0084] In the method for producing ammonia according to the present embodiment, the catalyst is usually heated when hydrogen and nitrogen are brought into contact on the catalyst to produce ammonia. The reaction temperature in the production method of this embodiment is not particularly limited, but is usually 200° C. or higher, preferably 250° C. or higher, and more preferably 300° C. or higher, and is usually 600° C. or lower, preferably 500° C. or lower, and more preferably 450° C. or lower. Since ammonia synthesis is an exothermic reaction, a lower temperature range is advantageous for ammonia production in terms of chemical equilibrium, but in order to obtain a sufficient ammonia production rate, it is preferable to carry out the reaction within the above temperature range. In the production method of this embodiment, the molar ratio of nitrogen to hydrogen brought into contact with the catalyst is not particularly limited, but is usually carried out at a ratio of hydrogen to nitrogen (H / N (volume / volume)) of usually 0.4 or more, preferably 0.5 or more, more preferably 1 or more, and usually 10 or less, preferably 5 or less.

[0085] The reaction pressure in the production method of this embodiment is not particularly limited, but is usually 0.01 MPa or more, preferably 0.1 MPa or more, and usually 20 MPa or less, preferably 15 MPa or less, more preferably 10 MPa or less, as the pressure of a mixed gas containing nitrogen and hydrogen. In consideration of practical use, it is preferable to carry out the reaction under pressurized conditions of atmospheric pressure or higher.

[0086] In the production method of this embodiment, before nitrogen and hydrogen are brought into contact with the catalyst, it is preferable to remove moisture and oxides adhering to the catalyst by a method using a dehydrating agent, a cryogenic separation method, hydrogen gas, etc. Examples of the removal method include reduction treatment. In the production method of this embodiment, in order to obtain a better ammonia yield, it is preferable that the water content in the nitrogen and hydrogen used in the production method of this embodiment is low. Although there are no particular limitations, it is generally preferable that the total water content in the mixed gas of nitrogen and hydrogen is 100 ppm or less, preferably 50 ppm or less.

[0087] In the production method of this embodiment, the type of reaction vessel is not particularly limited, and a reaction vessel that can be normally used for ammonia synthesis reactions can be used. Specific reaction types that can be used include, for example, a batch reaction type, a closed circulation reaction type, and a flow reaction type. Among these, a flow reaction type is preferred from a practical viewpoint. Furthermore, any of a single type of reactor filled with a catalyst, a method in which multiple reactors are connected, and a reactor having multiple reaction layers within the same reactor can be used. Since the reaction of synthesizing ammonia from hydrogen and nitrogen is an exothermic reaction accompanied by volume contraction, it is industrially preferable to remove the heat of reaction in order to increase the ammonia yield, and a known reaction apparatus equipped with a commonly used heat removal means may be used. Specifically, for example, a method of removing heat by connecting multiple reactors filled with a catalyst in series and installing an intercooler at the outlet of each reactor may be used.

[0088] In the ammonia production method of the present embodiment, the ammonia synthesis catalyst obtained by the production method of the present embodiment can be used alone or in combination with other known catalysts that can be normally used for ammonia synthesis.

[0089] As preferred aspects and specific examples of the catalyst composition according to the production method of this embodiment, the preferred aspects and specific examples described in the first and second embodiments of the catalyst composition can be cited.

[0090] <Other applications> The catalyst composition of the present invention can be used as a catalyst in various reactions. Specifically, it can be used for, for example, the hydrogenation of unsaturated bonds in olefins, acetylenes, aromatic rings, aldehyde groups, α-, β-unsaturated aldehydes, etc., the hydrocracking of hydrocarbons, hydrogen transfer reactions, etc. The transition metal supported in this case is not particularly limited, but typically Ni, Pd, Pt, Rh, Ru, etc. are used.

[0091] In the method of the present invention, either ammonia diluted with a balance gas or ammonia alone can be used as the raw material, i.e., ammonia gas with a volume fraction of 0.1 to 100%. When producing hydrogen by an ammonia decomposition reaction, it is necessary to separate the produced hydrogen and nitrogen, so a high ammonia volume fraction is preferable, with a volume fraction of 5% or more, more preferably 20% or more, and even more preferably 70% or more being suitable. The decomposition reaction is carried out at a weight hourly space velocity (WHSV) of 500 mlg-1h-1 or more, and a high NH3 conversion rate is obtained.

[0092] The gas produced by the ammonia decomposition method of the present invention theoretically contains hydrogen and nitrogen in a molar ratio of 3:1, and can be used, for example, as a gas for bright annealing stainless steel, nickel steel, nickel, nickel-copper, or nickel-chromium alloys. Furthermore, since the hydrogen produced by the present invention does not contain CO or CO2, which are harmful to fuel cells, it can be used, for example, as hydrogen for fuel cells by separating and purifying the produced hydrogen and nitrogen.

[0093] In other applications such as an ammonia decomposition reaction, the preferred aspects and specific examples of the catalyst composition to be used can be the same as those described in the first and second embodiments of the catalyst composition.

[0094] Other Embodiments of Use of Catalyst Additives Another embodiment of the use of the catalytic additive is the use of a catalytic additive represented by the following formula (1) for a reaction in which the electron donating ability of a chemical reaction catalyst is promoted to promote catalytic activity, and the mixture obtained by adding or mixing the catalytic additive to a chemical reaction catalyst or its precursor is carried out at a temperature of less than 700°C in the presence of a reducing gas or an inert gas. L m A n (1) (In formula (1), L represents at least one selected from the group consisting of transition elements and aluminum (Al), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number equal to or greater than 1, and n represents a number equal to or greater than 0.

[0095] The chemical reaction catalyst and catalyst additive used in the catalyst additive of this embodiment are preferably the embodiments and preferred examples of the chemical reaction catalyst and catalyst additive described in the above-mentioned catalyst composition. The descriptions thereof are incorporated herein by reference. [Example]

[0096] The present invention will be described in more detail below based on examples. The ammonia synthesis activity was evaluated by measuring the amount of NH3 produced by gas chromatography, or by dissolving the produced NH3 in an aqueous sulfuric acid solution and quantifying the solution by ion chromatography to determine the ammonia production rate.

[0097] (Ion chromatogram analysis) The ammonia gas discharged from the reaction vessel was dissolved in a 5 mM sulfuric acid solution, and the captured ammonium ions (NH + ) was analyzed by ion chromatography under the following analytical conditions:

[0098] [Measurement conditions] Equipment: Shimadzu Corporation Prominence Detector: Electrical conductivity detector CDD-10Avp (Shimadzu Corporation) Column: ion chromatography column IC-C4 (Shimadzu Corporation) Eluent: 3.0 mM oxalic acid + 2.0 mM 18-crown-6-ether aqueous solution Flow rate: 1.0 mL / min Column temperature: 40℃

[0099] Example 1 (Preparation of catalyst composition (ammonia synthesis catalyst)) [Synthesis of TiSi-doped Ru / Ba-MgO powder]

[0100] (I) Preparation of a mixture of Ru / Ba-MgO precursor and TiSi, which is a chemical reaction catalyst The MgO used was a product of Ube Materials Corporation (average particle size: 50 nm, purity: 99.98%, model number: 500A). An aqueous solution containing 0.0648 g of Ba(NO3), 0.1714 g of Ru(NO)(NO3) (corresponding to 5% by mass of supported metal Ru relative to the Ba-MgO), and 1.3 g of distilled water was prepared. 1.0 g of MgO powder was added to the solution, and the mixture was kneaded in a mortar for approximately 15 minutes to obtain a brown paste. 0.364 g of TiSi (25% by mass relative to the Ru / Ba-MgO) was added to the resulting paste, and the mixture was then dried at 140°C for approximately 2 hours to obtain a mixture of TiSi + MgO + Ba(NO3)2 + Ru(NO)(NO3)3.

[0101] (II) The mixture obtained above was heated in a nitrogen atmosphere under atmospheric pressure from room temperature to 400°C at a heating rate of 5°C / min, and then held at 450°C for an additional 4 hours. Thereafter, the mixture was cooled to room temperature to obtain a TiSi-added Ru / Ba-MgO powder as the catalyst composition (ammonia synthesis catalyst) of this example.

[0102] [Ammonia synthesis using TiSi-doped Ru / Ba-MgO] <Ammonia synthesis reaction> The TiSi-doped Ru / Ba-MgO catalyst was used to carry out an ammonia synthesis reaction by contacting this catalyst with a nitrogen and hydrogen mixed gas (N2 / H2 = 1 / 3 (v / v)). 0.1 g of the TiSi-doped Ru / Ba-MgO was packed into a stainless steel reaction tube, and the reaction was carried out using a fixed-bed flow reactor incorporating the reaction tube. The moisture concentrations of the nitrogen and hydrogen gas feedstocks were below their respective detection limits. The flow rates of the feedstock gases during this reaction were 15 mL / min for nitrogen gas and 45 mL / min for hydrogen gas (total 60 mL / min). The reaction pressure during this reaction was 0.9 MPa, the reaction temperature was 400°C, and the reaction time was 30 hours. A pretreatment reaction was carried out at 450°C for 20 hours under the same conditions as the ammonia synthesis reaction described above. The catalytic activity was then evaluated under the same reaction conditions. Similarly, an ammonia synthesis reaction was also carried out under a reaction pressure of 0.9 MPa, a reaction temperature of 340°C, and a reaction time of 30 hours.

[0103] <Ammonia production rate> The gas discharged from the fixed-bed flow reactor was bubbled through a 0.005 M aqueous sulfuric acid solution, thereby dissolving the ammonia in the gas into the solution. The ammonium ions produced in the solution were quantified by the above-mentioned method using ion chromatography. The rate of ammonia production produced by the ammonia synthesis reaction was measured over time using ion chromatography. The results showed that the TiSi-added Ru / Ba-MgO catalyst exhibited higher catalytic activity than the TiSi-free Ru / Ba-MgO catalyst (see Figure 4 and Table 1). The ammonia production rate over the TiSi-doped Ru / Ba-MgO catalyst at 400°C was 39.4 mmol / g hr. The results are shown in FIG.

[0104] <Changes in the ammonia synthesis reaction over time> The ammonia synthesis rate was measured at 400°C and 0.9 MPa in the same manner as above, except for the reaction time. The results are shown in Figure 7. The TiSi-doped Ru / Ba-MgO catalyst showed stable catalytic activity with almost no decrease in the ammonia production rate even after continuous reaction for more than 300 hours.

[0105] Examples 2 to 5 [Synthesis of TiSi-doped Ru / Ba-MgO powder] The TiSi-doped Ru / Ba—MgO powders of Examples 2 to 5 were obtained in the same manner as in Example 1, except that 0.0437 g (addition amount: 3 wt%), 0.146 g (addition amount: 10 wt%), 0.255 g (addition amount: 17.5 wt%), and 0.728 g (addition amount: 50 wt%) of TiSi were added, respectively.

[0106] [Ammonia synthesis using TiSi-doped Ru / Ba-MgO] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 340°C and 0.9 MPa, and at 400°C and 0.9 MPa. The results are shown in Figure 1.

[0107] Example 6 The ammonia synthesis activity of TiSi-added Ru / Ba-MgO was evaluated under the same conditions as in Example 1, except that the pretreatment conditions were a nitrogen atmosphere and 600°C. Specifically, the ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 2. Figure 2 also shows the ammonia synthesis activity in a test plot where the pretreatment conditions for the ammonia synthesis reaction were a nitrogen and hydrogen mixed gas (N2 / H2 = 1 / 3 (v / v)) atmosphere and 450°C (i.e., the ammonia synthesis activity of TiSi-added Ru / Ba-MgO under the same conditions as in Example 1), and the ammonia synthesis activity in a test plot without TiSi added (i.e., the ammonia synthesis activity of (TiSi-free) Ru / Ba-MgO under the same conditions as in Comparative Example 1).

[0108] Example 7 The ammonia synthesis activity of the TiSi-added Ru / Ba-MgO was evaluated under the same conditions as in Example 1, except that the pretreatment temperature was 600°C. An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 4.

[0109] Example 8 [Fe loading on Ba-MgO] The TiSi-doped Fe / Ba-MgO powder of this example was obtained in the same manner as in Example 1, except that 1.8 g of Fe(NO)·9(HO) (corresponding to 20 mass% of supported metallic Fe relative to Ba-MgO) was used instead of Ru(NO)(NO)3. An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 4.

[0110] Example 9 The ammonia synthesis activity of TiSi-added Fe / Ba—MgO was evaluated under the same conditions as in Example 8, except that the pretreatment temperature was 600° C. The results are shown in FIG.

[0111] Example 10 [Co support on Ba-MgO] The TiSi-doped Co / Ba-MgO powder of this example was obtained in the same manner as in Example 1, except that 80.118 g of Co(CO) (corresponding to 8% by mass of supported metal Co relative to Ba-MgO) was used instead of Ru(NO)(NO)3. An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 4.

[0112] Example 11 The ammonia synthesis activity of TiSi-doped Co / Ba-MgO was evaluated under the same conditions as in Example 10, except that the pretreatment temperature was 600°C. The ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 4.

[0113] [Catalyst additives other than TiSi] Example 12 The Ti-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of Ti (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0114] Example 13 The TiO-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of TiO (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0115] Example 14 The TiN-added Ru / Ba-MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of TiN (25 mass % as an added amount relative to Ru / Ba-MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0116] Example 15 The TiC-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of TiC (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0117] Example 16 The Fe-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of Fe (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0118] Example 17 Ni-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of Ni (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0119] Example 18 The Al-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of Al (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5. The ammonia synthesis rate was also measured at 340°C and 0.9 MPa. The results are shown in Figure 6.

[0120] Example 19 Si-added Ru / Ba—MgO powder of this example was obtained in the same manner as in Example 1, except that 0.364 g of Si (25 mass % as an added amount relative to Ru / Ba—MgO) was used instead of TiSi 2 . An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 5.

[0121] (Comparative Example 1) [Synthesis of Ru / Ba-MgO powder] A Ru / Ba—MgO powder was obtained in the same manner as in Example 1, except that TiSi was not added.

[0122] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 340° C. and 400° C. under 0.9 MPa. The results are shown in FIGS.

[0123] (Comparative Example 2) The ammonia synthesis rate at 400°C and 0.9 MPa was measured under the same conditions as in Comparative Example 1, except that the pretreatment condition was 600°C, and the ammonia synthesis activity of Ru / Ba-MgO was evaluated. The results are shown in Figure 3.

[0124] (Comparative Example 3) [Synthesis of Ru / TiSi powder] An aqueous solution containing 0.1714 g of Ru(NO)(NO3)3 (corresponding to 5% by mass of supported metal Ru relative to TiSi) and 1.3 g of distilled water was prepared. 1.0 g of TiSi powder was added to the aqueous solution, and the mixture was kneaded in a mortar for approximately 15 minutes. The resulting mixture was then dried at 140°C for approximately 2 hours to obtain a mixture of TiSi and Ru(NO)(NO3)3. (2) The mixture obtained above was heated in a nitrogen gas atmosphere under atmospheric pressure from room temperature to 400°C at a temperature increase rate of 5°C / min, and then maintained at 450°C for an additional 4 hours. Thereafter, the mixture was cooled to room temperature to obtain a Ru / TiSi powder of this comparative example as the catalyst composition of this example (ammonia synthesis catalyst).

[0125] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 3.

[0126] Comparative Example 4 [Fe loading on Ba-MgO] The Fe / Ba-MgO powder of this comparative example was obtained in the same manner as in Comparative Example 1, except that 1.8 g of Fe(NO3)3·9(HO) (corresponding to 20 mass% of supported metallic Fe relative to Ba-MgO) was used instead of Ru(NO)(NO3)3.

[0127] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 4.

[0128] (Comparative Example 5) The ammonia synthesis activity of Fe / Ba—MgO was evaluated under the same conditions as in Comparative Example 4, except that the pretreatment condition was 600° C. The results are shown in FIG.

[0129] (Comparative Example 6) [Co support on Ba-MgO] The Co / Ba-MgO powder of this comparative example was obtained in the same manner as in Comparative Example 1, except that 80.118 g of Co2(CO) (corresponding to 8 mass% of supported metal Co relative to Ba-MgO) was used instead of Ru(NO)(NO3)3.

[0130] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Figure 4.

[0131] (Comparative Example 7) The ammonia synthesis activity of Co / Ba—MgO was evaluated under the same conditions as in Comparative Example 6, except that the pretreatment condition was 600° C. The results are shown in FIG.

[0132] Example 20 (Preparation of catalyst composition (ammonia synthesis catalyst)) [Synthesis of TiSi-doped Ru / Sr-MgO powder] (I) Preparation of a mixture of Ru / Sr-MgO precursor and TiSi, which is a chemical reaction catalyst An aqueous solution containing 0.0525 g of Sr(NO3)2, 0.1714 g of Ru(NO)(NO3)3 (corresponding to 5% by mass of supported metal Ru relative to the Ba-MgO), and 1.3 g of distilled water was prepared. 1.0 g of MgO powder was added to the aqueous solution, and the mixture was kneaded in a mortar for approximately 15 minutes to obtain a paste. 0.364 g of TiSi (25% by mass relative to the Ru / Sr / MgO) was added to the resulting paste, and the mixture was then dried at 140°C for approximately 2 hours to obtain a mixture of TiSi + MgO + Sr(NO3)2 + Ru(NO)(NO3)3. (II) The mixture obtained above was heated in a nitrogen gas atmosphere under atmospheric pressure from room temperature to 400°C at a heating rate of 5°C / min, and then maintained at 450°C for 4 hours. After that, it was cooled to room temperature to obtain a TiSi-added Ru / Sr-MgO powder as the catalyst composition (ammonia synthesis catalyst) of this example.

[0133] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0134] Example 21 (Preparation of catalyst composition (ammonia synthesis catalyst)) [Synthesis of TiSi-doped Ru / BaAl2O4 powder] (I) Preparation of a mixture of Ru / BaAl2O4 precursor and TiSi, which is a chemical reaction catalyst 0.148 g of barium carbonate (Wako Pure Chemicals, 99.9%) and 0.117 g of aluminum hydroxide (Kojundo Chemical, 99.99%) were mixed so that the molar ratio of Ba to Al was 1:2. The resulting mixture was placed in an alumina crucible, heated to 1000°C for 3 hours, and maintained at this temperature for 10 hours to obtain BaAl2O4 oxide. The obtained powder BaAl2O4 0.50 g and Ru3(CO) 120.056 g (Aldrich, 99%) (corresponding to 5% by mass of supported metal Ru relative to BaAlO) was inserted into a silica glass tube, which was then heated at 70°C for 1 hour in a vacuum. Subsequently, this was heated at 120°C for 1 hour, forming Ru(CO) on the surface of the powdered BaAlO. 12 was attached. The Ru3(CO) thus obtained 12 The powdered BaAl2O4 to which Ru3(CO) was attached was heated at 250°C for 2 hours. 12 By thermal decomposition of the above, a support in which Ru was fixed on BaAl2O4 (hereinafter referred to as Ru / BaAl2O4) was obtained. The obtained powdered Ru / BaAl2O4 (1.0 g), TiSi (0.364 g), and dodecane (1.3 g) were mixed in a mortar, and the resulting mixture was dried at 140°C for about 2 hours. The mixture was then heated from room temperature to 400°C at a rate of 5°C / min in a nitrogen gas atmosphere under atmospheric pressure, and then heated by holding at 450°C for another 4 hours. The mixture was then cooled to room temperature to obtain a mixture of TiSi + Ru / BaAl2O4.

[0135] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0136] [Table 1]

[0137] Example 22 (Preparation of catalyst composition (ammonia synthesis catalyst)) [Synthesis of TiSi-doped Ru / CeO2 powder] (I) Preparation of a mixture of Ru / CeO2 precursor and TiSi, which is a chemical reaction catalyst An aqueous solution containing 0.1714 g of Ru(NO)(NO)3 (corresponding to 5% by mass of supported metal Ru relative to CeO) and 1.3 g of distilled water was prepared. 1.0 g of CeO2 powder was added to the aqueous solution and kneaded in a mortar for approximately 15 minutes to obtain a paste. 0.364 g of TiSi (25% by mass relative to Ru / CeO2) was added to the resulting paste and kneaded in a mortar. The resulting mixture was then dried at 140°C for approximately 2 hours to obtain a mixture of TiSi + CeO2 + Ru(NO)(NO3)3. (II) The resulting mixture was heated from room temperature to 400°C at a rate of 5°C / min in a nitrogen gas atmosphere under atmospheric pressure, and then maintained at 450°C for an additional 4 hours. The mixture was then cooled to room temperature to obtain TiSi-doped Ru / CeO2 powder as the catalyst composition (ammonia synthesis catalyst) of this example.

[0138] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0139] Example 23 (Preparation of catalyst composition (ammonia synthesis catalyst)) [Synthesis of TiSi-doped Ru / Ba-CeO2 powder] (I) Preparation of a mixture of Ru / Ba-CeO2 precursor and TiSi, which is a chemical reaction catalyst An aqueous solution containing 0.0648 g of Ba(NO3)2, 0.1714 g of Ru(NO)(NO3)3 (corresponding to 5% by mass of supported metal Ru relative to Ba-CeO2), and 1.3 g of distilled water was prepared. 1.0 g of CeO2 powder was added to the solution and kneaded in a mortar for approximately 15 minutes to obtain a paste. 0.364 g of TiSi (25% by mass relative to Ru / Ba-CeO2) was added to the resulting paste and kneaded in a mortar. The resulting mixture was then dried at 140°C for approximately 2 hours to obtain a mixture of TiSi + CeO2 + Ba(NO3)2 + Ru(NO)(NO3)3. (II) The mixture obtained above was heated in a nitrogen gas atmosphere under atmospheric pressure from room temperature to 400°C at a heating rate of 5°C / min, and then held at 450°C for an additional 4 hours. After that, it was cooled to room temperature to obtain a TiSi-added Ru / Ba-CeO2 powder as the catalyst composition (ammonia synthesis catalyst) of this example.

[0140] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0141] (Comparative Example 8) [Synthesis of Ru / Sr-MgO powder] A Ru / Sr—MgO powder was obtained in the same manner as in Example 20, except that TiSi was not added.

[0142] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0143] Comparative Example 9 [Synthesis of Ru / BaAl2O4 powder] Ru / BaAl2O4 powder was obtained in the same manner as in Example 21, except that TiSi was not added.

[0144] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0145] (Comparative Example 10) [Synthesis of Ru / CeO2 powder] Ru / CeO2 powder was obtained in the same manner as in Example 22, except that TiSi was not added.

[0146] <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0147] (Comparative Example 11) [Synthesis of Ru / Ba-CeO2 powder] Ru / Ba-CeO2 powder was obtained in the same manner as in Example 23, except that TiSi was not added. <Ammonia synthesis reaction> An ammonia synthesis reaction was carried out under the same conditions as in Example 1. The ammonia synthesis rate was measured at 400°C and 0.9 MPa. The results are shown in Table 1.

[0148] (Consideration) The results of each example and comparative example shown in the figures and tables will be explained below. The present invention is not limited to the configurations of each example.

[0149] The addition of TiSi, a catalytic additive, to the Ru / Ba-MgO catalyst and other chemical reaction catalysts has been shown to improve ammonia synthesis activity. In rare-earth oxide-supported chemical reaction catalysts such as Ru / CeO2, the addition of TiSi appears to have a similar effect by abstracting oxygen from the oxide, even without high-temperature hydrogen reduction. A similar effect is also observed in Ba-containing metal oxides such as BaAl2O4, suggesting that the addition of TiSi to other Ba-containing composite oxides may also be effective. Furthermore, the addition of TiSi to the Ru / Sr-MgO catalyst, in which Sr is added instead of Ba, also exhibited improved ammonia synthesis activity. Furthermore, in the case of the most active Ru / Ba-MgO catalyst, the effect of TiSi addition is thought to be due to the formation of oxygen vacancies in BaO rather than MgO, resulting in electron donation from the electrons formed at the F centers, which resulted in high catalytic activity. Furthermore, in the case of SrO catalysts, which are second only to BaO in oxygen vacancies formation, the addition of TiSi is thought to result in the formation of oxygen vacancies in SrO, thereby exhibiting electron-donating properties.

[0150] <Figure 1> FIG. 1 shows the relationship between the amount of catalyst additive added and the catalytic effect for the catalyst compositions (ammonia synthesis catalysts) of this embodiment in Examples 1 to 5. Compared with the ammonia production rate of the Ru / Ba-MgO catalyst before the addition of TiSi (21.8 mmol / g hr), the ammonia production rate increased with increasing TiSi content, reaching a maximum when 25 wt% TiSi was added.

[0151] <Figure 2> Even when pretreated at 600°C in an N2-only gas atmosphere, the ammonia synthesis activity of the TiSi-doped Ru / Ba-MgO catalyst was equivalent to that of a TiSi-doped Ru / Ba-MgO catalyst pretreated at 450°C in an N2+H2 atmosphere. This indicates that the catalyst can be reductively activated in the presence of a reducing agent such as TiSi, even without using hydrogen gas during pretreatment.

[0152] <Figure 3> Under the same conditions as in Example 1, the ammonia synthesis activity of the TiSi-added Ru / Ba-MgO catalyst was compared with that of a TiSi-free Ru / Ba-MgO catalyst pretreated at 600°C. In general, the catalytic activity of Ru-based catalysts is often significantly improved by high-temperature reduction in a hydrogen-containing atmosphere. As shown in Figure 3, the ammonia production rate of the Ru / Ba-MgO catalyst pretreated at 450°C was 21.8 mmol / g·hr, but increased to 40.3 mmol / g·hr when pretreated at 600°C. On the other hand, the ammonia synthesis activity of the TiSi-added Ru / Ba-MgO catalyst pretreated at 450°C was comparable to that of the Ru / Ba-MgO catalyst pretreated at 600°C without any catalyst additives such as TiSi. The Ru / TiSi catalyst showed almost no ammonia synthesis activity, indicating that TiSi itself has no catalytic activity and that TiSi can enhance the catalytic activity of the catalyst composition containing the Ru / Ba-MgO catalyst at lower temperatures. The TiSi forms oxygen vacancies in BaO, which then donate electrons from the F center formed just below the conduction band edge of BaO, significantly enhancing the activity of the Ru catalyst.

[0153] <Figure 4> When pretreated at 450°C, the addition of TiSi increased the ammonia synthesis activity of the Ru / Ba-MgO catalyst by approximately 1.8 times, but when pretreated at 600°C, the addition of TiSi increased the ammonia synthesis activity of the Ru / Ba-MgO catalyst by approximately 1.26 times. Thus, although the rate of improvement in ammonia synthesis activity decreased, it was shown that the experimental system in which TiSi was added was more effective in promoting catalytic activity, even in high-temperature pretreatment. Furthermore, a catalyst composition in which a metal-supported catalyst carrying Fe or Co was used instead of Ru as the chemical reaction catalyst (metal-supported catalyst) and TiSi was added to the metal-supported catalyst as a catalyst additive showed improved ammonia synthesis activity compared to a catalyst without a catalyst additive, similar to Ru / Ba-MgO with TiSi added. Furthermore, when pretreated at 450°C, the addition of TiSi hardly changed the ammonia synthesis activity of the Fe / Ba-MgO catalyst, but when pretreated at 600°C, the addition of TiSi improved the ammonia synthesis activity of the Fe / Ba-MgO catalyst by approximately 1.5 times. It was found that when Fe is supported, relatively strong pretreatment conditions are required, even when TiSi is added. On the other hand, when pretreated at 450°C, the ammonia synthesis activity of the Co / Ba-MgO catalyst increased by approximately 1.8 times with the addition of TiSi. When pretreated at 600°C, the ammonia synthesis activity of the Co / Ba-MgO catalyst increased by approximately 1.5 times with the addition of TiSi.

[0154] <Figures 5 and 6> We enhanced the catalytic activity of the catalyst composition by adding various substances instead of TiSi as a catalyst additive to the Ru / Ba-MgO catalyst and then pretreating it. For most of the tested substances, the ammonia synthesis activity was significantly improved compared to the original (non-additive) Ru / Ba-MgO catalyst. The effect of adding the catalyst additive was particularly pronounced in experimental systems using Ti-based compounds. Among these, the addition of Ti was more effective in improving ammonia synthesis activity than the addition of TiSi. On the other hand, the addition of Si hardly demonstrated any effect (i.e., improved ammonia synthesis activity). While the mechanism behind the improvement in ammonia activity due to the catalyst additive of the present invention is not yet fully understood, we believe that all of the tested substances added to the catalyst composition are easily oxidized, and that this is due to the extraction of oxygen from BaO present in the Ru / Ba-MgO catalyst. Among alkaline earth metal oxides, BaO has a low oxygen vacancy formation energy and the F center is formed just below the conduction band minimum, making it an electron donor. This function is thought to act as an electronic promoter, resulting in a significant improvement in the activity of the Ru catalyst.

[0155] <Effects of adding catalyst additives> Although the reaction mechanism related to the effects shown in the above examples is still unclear, it is thought that oxides such as BaO, which form oxygen vacancies, have high electron donating properties because F centers are formed near the bottom of the conduction band and can form a surface with a low work function. When forming such oxygen vacancies, it is thought to be important to add a substance with high oxygen abstraction ability, such as TiSi, to the chemical reaction catalyst as a catalyst additive.

[0156] The catalyst additive is used as a promoter or promoter-like substance for the chemical reaction catalyst. Here, a "promoter-catalyst-like substance" is a substance that does not have a catalytic action by itself greater than the intended or targeted catalytic action of the chemical reaction catalyst, but which, together with the intended or targeted reaction catalyst, has the effect of assisting the catalytic chemical reaction accelerated by the reaction catalyst (by strengthening the catalytic action that the reaction catalyst exhibits by itself or by compensating for the shortcomings of the reaction catalyst). Here, a "co-catalyst" is a substance that does not have catalytic activity by itself, but that, together with a target or targeted reaction catalyst, has the effect of assisting the catalytic chemical reaction that the target reaction catalyst accelerates (by strengthening the catalytic activity that the target reaction catalyst exhibits on its own or compensating for the shortcomings of the target reaction catalyst).

[0157] For example, the reaction mechanism may be as follows: As a co-catalyst, a catalyst additive such as titanium silicide (TiSix) in Example 1 extracts oxygen ions from the crystal structure of a chemical reaction catalyst (e.g., an oxide such as BaO / CeO2) and replaces them with electrons. The electrons themselves become anions, forming ionic crystals (i.e., electrides). These ionic crystals are chemically and thermally stable in the atmosphere, while being just as likely to release electrons as alkali metals. These electrons then act, for example, to break nitrogen-nitrogen triple bonds, thereby promoting the ammonia synthesis reaction.

[0158] On the other hand, in the case of conventional catalysts that do not contain a promoter, it is known that the catalytic activity of the reaction catalyst can be improved by adding a "catalytically active metal component" such as Ru to the reaction catalyst and then subjecting it to hydrogen reduction at high temperatures. This has led to problems such as a decrease in the stability of the reaction catalyst and a large load on the reactor due to high-temperature hydrogen treatment. By using the catalyst additive of the present invention as a promoter, it is expected that the decrease in catalyst stability and the load on the reactor due to high-temperature hydrogen treatment can be suppressed.

Claims

1. A catalyst additive represented by the following formula (1); A chemical reaction catalyst containing a catalytic substance represented by the following formula (2-1): A catalyst composition comprising: the chemical reaction catalyst and the catalyst composition have ammonia synthesis activity, A catalyst composition, wherein the ammonia synthesis activity of the catalyst composition exceeds the ammonia synthesis activity of the chemical reaction catalyst. L ｍ A ｎ (1) (In formula (1), L is titanium (Ti), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number of 1 or more, and n is 0 or 1. M ｐ O ｑ (2-1) (In formula (2-1), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La); p represents a number of 1 or more, and q represents a number of 1 or more.

2. 2. The catalyst composition of claim 1, wherein the catalyst additive is at least one selected from the group consisting of Ti, TiSi, TiO, TiN, and TiC.

3. The catalytic material is Ba—MgO, Sr—MgO, CeO ２ , Ba—CeO ２ 3. The catalyst composition according to claim 1, wherein the catalyst composition is one selected from the group consisting of:

4. The chemical reaction catalyst further comprises a catalytically active metal; the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, 3. The catalyst composition according to claim 1, wherein the support is the catalyst material represented by formula (2-1).

5. 5. The catalyst composition according to claim 4, wherein the catalytically active metal is at least one selected from the group consisting of ruthenium (Ru), cobalt (Co), iron (Fe), nickel (Ni), molybdenum (Mo), rhodium (Rh), rhenium (Re), chromium (Cr), and manganese (Mn).

6. 5. The catalyst composition of claim 4, wherein the support is a basic metal oxide.

7. 7. The catalyst composition according to claim 6, wherein the support is a crystalline basic metal oxide.

8. 5. The catalyst composition of claim 4, wherein the catalytically active metal is one selected from the group consisting of Ru, Co, and Fe.

9. A method for promoting catalytic activity, comprising the step of adding or mixing a catalyst additive to a chemical reaction catalyst or a precursor thereof, thereby promoting the electron donating ability of the chemical reaction catalyst and promoting catalytic activity, The method includes a step of adding or mixing the catalyst additive with a chemical reaction catalyst or a precursor thereof, and reacting the mixture obtained under a temperature condition of 400°C or higher and lower than 700°C in the presence of a reducing gas or an inert gas to obtain a catalyst composition; The catalyst additive is a catalyst additive represented by the following formula (1): The chemical reaction catalyst is a chemical reaction catalyst containing a catalytic substance represented by the following formula (2-1): the chemical reaction catalyst and the catalyst composition have ammonia synthesis activity, The method for promoting catalytic activity, wherein the ammonia synthesis activity of the catalyst composition exceeds the ammonia synthesis activity of the chemical reaction catalyst. L ｍ A ｎ (1) (In formula (1), L is titanium (Ti), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number of 1 or more, and n is 0 or 1. M ｐ O ｑ (2-1) (In formula (2-1), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La); p represents a number of 1 or more, and q represents a number of 1 or more.

10. 10. The method for promoting catalytic activity according to claim 9, wherein the temperature condition is 450°C or higher and 600°C or lower.

11. The chemical reaction catalyst further comprises a catalytically active metal; the chemical reaction catalyst is a metal support in which the catalytically active metal is supported on a carrier, 11. The method for promoting catalytic activity according to claim 9, wherein the support is the catalytic substance represented by formula (2-1).

12. A method for producing a catalyst composition, comprising the steps of: a first step of mixing the catalyst additive with the chemical reaction catalyst or a precursor thereof; a second step of reacting the first mixture obtained in the first step under a temperature condition of 400°C or higher and lower than 700°C in the presence of a reducing gas or an inert gas; A method for producing a catalyst composition, comprising:

13. A catalyst additive; a chemical reaction catalyst or a precursor thereof; a first step of mixing the above; a second step of reacting the first mixture obtained in the first step under a temperature condition of 400°C or higher and lower than 700°C in the presence of a reducing gas or an inert gas; A method for producing a catalyst composition, comprising: the chemical reaction catalyst and the catalyst composition have ammonia synthesis activity, the ammonia synthesis activity of the catalyst composition exceeds the ammonia synthesis activity of the chemical reaction catalyst; The catalyst additive is a catalyst additive represented by the following formula (1): The method for producing a catalyst composition, wherein the chemical reaction catalyst is a chemical reaction catalyst containing a catalytic substance represented by the following formula (2-1): L ｍ A ｎ (1) (In formula (1), L is titanium (Ti), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number of 1 or more, and n is 0 or 1. M ｐ O ｑ (2-1) (In formula (2-1), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La); p represents a number of 1 or more, and q represents a number of 1 or more.

14. The method for producing a catalyst composition according to claim 12, wherein the temperature condition is 450°C or higher and 600°C or lower.

15. The method for producing a catalyst composition according to claim 12, further comprising: a third step of obtaining the catalyst composition using the second mixture obtained in the second step without removing the catalyst additive contained in the second mixture.

16. The method for producing a catalyst composition according to claim 12, further comprising: a third step of removing the catalyst additive contained in the second mixture using the second mixture obtained in the second step.

17. A method for producing a hydrogenated product, comprising the step of reacting a raw material compound to be hydrogenated with hydrogen in the presence of the catalyst composition according to claim 1 or 2.

18. 3. A method for producing ammonia, comprising a step of reacting nitrogen with hydrogen in the presence of the catalyst composition according to claim 1.

19. In a catalytic activity promoting reaction for promoting the electron donating ability of a chemical reaction catalyst containing a catalytic substance represented by the following formula (2-1) to promote catalytic activity, a mixture obtained by adding or mixing a catalytic additive to the chemical reaction catalyst or a precursor thereof is reacted under a temperature condition of 400°C or higher and lower than 700°C in the presence of a reducing gas or an inert gas, to obtain a catalyst composition, using the catalytic additive represented by the following formula (1): the chemical reaction catalyst and the catalyst composition have ammonia synthesis activity, The ammonia synthesis activity of the catalyst composition exceeds the ammonia synthesis activity of the chemical reaction catalyst. L ｍ A ｎ (1) (In formula (1), L is titanium (Ti), A represents at least one selected from the group consisting of silicon (Si), oxygen (O), nitrogen (N), and carbon (C); m represents a number of 1 or more, and n is 0 or 1. M ｐ O ｑ (2-1) (In formula (2-1), M represents one or more elements selected from the group consisting of barium (Ba), cerium (Ce), magnesium (Mg), calcium (Ca), strontium (Sr), and lanthanum (La); p represents a number of 1 or more, and q represents a number of 1 or more.

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