KR20220131726A - A nitride catalysts for synthesize ammonia at low temperature and low temperature ammonia synthesis from water and air by using nitride catalysts - Google Patents

Abstract

A catalyst according to the present invention comprises: a metal nitride compound containing a transition metal as a main component so that a large amount of ammonia can be synthesized even at a much lower temperature or under low energy compared to a conventional Haber-Bosch process or an electrochemical synthesis method, and eco-friendly ammonia which does not generate impurities such as carbon dioxide can be synthesized by using water and air at the same time. In addition, the catalyst consumes much less energy than an electrical synthesis method and does not use an electrode so that there is no worry of corrosion and the generation of additional impurities can be suppressed.

Description

A nitride catalysts for synthesize ammonia at low temperature and low temperature ammonia synthesis from water and air by using nitride catalysts

The present invention relates to a method for synthesizing ammonia from water and air at a low temperature using a nitride catalyst, and more particularly, by using a metal compound containing a transition metal as a catalyst, compared to the existing Haber-Bosch process It relates to a method for low-temperature synthesis of ammonia from water and air using a nitride catalyst capable of synthesizing a large amount of ammonia even at a much lower temperature and pressure and capable of synthesizing environmentally friendly ammonia using only water and air.

Ammonia (NH ₃ ) is a compound of hydrogen and nitrogen. It is colorless, has an irritating smell, and exists in a gaseous state at room temperature. There are three hydrogen atoms forming an equilateral triangle with a side of 0.163 nm, and the nitrogen atom floats 0.038 nm from the center of the equilateral triangle, indicating the molecular structure in a triangular pyramid. A pair of lone pairs of electrons exists in the nitrogen atom making up ammonia, which allows ammonia to act as a proton acceptor, that is, a base. Since the dipole moment of ammonia is not zero due to its triangular pyramidal molecular structure, it becomes a polar substance. Ammonia has hydrogen bonds, the length of the NH bond in the ammonia molecule is 0.1014 nm, and the bond angle of HNH is 107°. It is contained in a small amount in the atmosphere, is contained in a trace amount in natural water, and may exist in the soil as it is generated in the process of decomposing nitrogen organic matter of bacteria.

Ammonia is used as an ingredient in synthetic fertilizers. Nitrogen is one of the essential elements for plant growth. Naturally, nitrogen fixation occurs in which some bacteria in the soil fix nitrogen in the air with nitrogen compounds, and through this, plants can absorb nitrogen. Urea fertilizer made by using ammonia synthesized by fixing nitrogen in the air acts as a nitrogen source in the soil to supply abundant nitrogen to crops, and as a result, crop production is increased.

Ammonium nitrate, which has the chemical formula of NH ₄ NO ₃ as the nitrate of ammonia, is relatively safe even at about 200°C, but acts as a strong oxidizer and causes an explosion when combined with fuels such as petroleum. A bomb manufactured using this property of ammonium nitrate is called a fertilizer bomb, and ammonia is used as a raw material for explosives. In addition to being used as a raw material for synthesis of ammonium salt, nitric acid and urea, ammonia is used as a raw material for various chemical industries, for the manufacture of ammonia water, and as a solvent for ionic substances.

The Haber-Bosch process, which is the most common method for producing ammonia, produces ammonia molecules as shown in Reaction Equation 1 on a metal catalyst at high temperature (eg 475°C) and high pressure (eg 20 MPa) by gaseous hydrogen and nitrogen and generates 100 kJ of energy. It is an exothermic process that Although this process is a proven large-scale industrial process, it not only has a low reaction yield of 10 to 20%, but also consumes the second most energy in the world (average 32 GJ/ton NH ₃ ), and produces hydrogen from natural gas or coal. Because of this, there is a problem of discharging a large amount of CO ₂ (3.45 kg CO ₂ /kg NH ₃ ).

[Scheme 1]

N ₂ + 3H ₂ -> 2NH ₃ + 100 kJ

Many studies have been conducted to solve the disadvantages of the Haber-Bosch method. Among them, the electrochemical ammonia synthesis method using a proton conductive membrane ionizes not only hydrogen but also hydrogen contained in water into protons to produce nitrogen, unlike the existing Haber-Bosch method. It has the advantage of being able to react with gas at atmospheric pressure (1 atm).

However, in this electrochemical ammonia synthesis method, since the amount of proton ionization of hydrogen and water is controlled according to the supplied current, the ammonia yield can be precisely controlled according to the applied external current. It is a catalyst for this purpose and has a disadvantage in that it has a low ammonia yield compared to an externally applied current because the nitrogen dissociation activity is very low. Therefore, compared to the Haber-Bosch method, equivalent or more energy is required to synthesize the same amount of ammonia.

US Patent Publication No. 2012-0241328 (September 27, 2012)

The present invention has been devised to solve the above problems, and in detail, by using a metal compound containing a transition metal as a catalyst, it is much better than the conventional Haber-Bosch process or electrochemical synthesis method. It relates to a low-temperature synthesis method of ammonia from water and air using a nitride catalyst capable of synthesizing a large amount of ammonia at low temperature and pressure or under low energy, and capable of synthesizing environmentally friendly ammonia using only water and air.

The present invention relates to a nitride catalyst for low-temperature synthesis of ammonia and a method for low-temperature synthesis of ammonia from water and air using the nitride catalyst.

One aspect of the present invention relates to a nitride catalyst for the low-temperature synthesis of ammonia having the composition of Formula 1 below.

[Equation 1]

M _2-x R _x Si _y N _z

(In Formula 1, M is any one element selected from magnesium, calcium, strontium and barium, and R is lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, Any one element selected from ytterbium, lutetium, nickel, iron, molybdenum and tungsten, 0≤x≤2, 4≤y≤6, and 7≤z≤9)

In this case, more preferably in Formula 1, M is any one selected from calcium, strontium and barium, R is europium, erbium, iron and tungsten, wherein x is 0.001≤x≤0.5, and z is 7.5≤z ≤8.5, respectively.

Another aspect of the present invention is

a1) preparing a slurry by mixing the catalyst for low-temperature synthesis of ammonia with distilled water;

b1) injecting any one or a plurality of gases selected from nitrogen, hydrogen, air and water vapor into the slurry into the reactor; and

c1) heating the reactor to a temperature of 30 to 100 °C;

include, or

a2) injecting a catalyst for low-temperature synthesis of ammonia into a reactor;

b2) injecting any one or a plurality of gases selected from nitrogen, hydrogen, air and water vapor into the reactor into the reactor; and

c2) heating the reactor to a temperature of 30 to 100 °C;

It relates to a low-temperature synthesis method of ammonia from water and air using a nitride catalyst comprising a.

The catalyst according to the present invention contains a metal compound including a transition metal as a main component, so that a large amount of it at a much lower temperature and pressure or under low energy than the conventional Haber-Bosch process or electrochemical synthesis method. Ammonia synthesis is possible, and at the same time, it has the advantage of synthesizing environmentally friendly ammonia that does not generate impurities such as carbon dioxide using water and air.

In addition, it consumes much less energy compared to the electrical synthesis method, and since it does not use an electrode, there is no concern about corrosion and the generation of additional impurities can be suppressed.

1 shows the results of the synthesis of ammonia when the catalysts of Examples 1 to 4 were used.
2 shows the results of the synthesis of ammonia when the catalysts of Examples 3 and 5 to 8 were used.
3 shows the results of the synthesis of ammonia when the catalysts of Examples 6 and 9 to 12 were used.

Hereinafter, a nitride catalyst for low-temperature synthesis of ammonia according to the present invention and a method for low-temperature synthesis of ammonia from water and air using the same will be described in more detail by way of Examples and Comparative Examples. However, the embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art.

Therefore, the present invention is not limited to the embodiments presented below and may be embodied in other forms, and the embodiments presented below are merely described to clarify the spirit of the present invention, and the present invention is not limited thereto.

At this time, unless there are other definitions in the technical terms and scientific terms used, it has the meaning commonly understood by those of ordinary skill in the technical field to which this invention belongs, and in the following description, it may unnecessarily obscure the subject matter of the present invention. Descriptions of possible known functions and configurations will be omitted.

Also, the singular forms used in the specification and appended claims may be intended to include the plural forms unless the context specifically dictates otherwise.

In the present invention, the terms 'catalyst composition' and 'catalyst' are synonymous and may be used interchangeably.

In the present invention, 'transition metal' includes lanthanide (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), and terbium ( Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), nickel (Ni), iron (Fe), molybdenum (Mo) and tungsten (W). However, promethium (Pm), one of the lanthanide elements, naturally exists in a very trace amount (about 600 g) in the earth's crust, and its production method is very difficult, so it is excluded.

The present invention is a transition to nitrides containing group 2 elements, silicon and nitrogen while intensive research has been repeated to solve the problems such as low yield, excessive energy consumption, and carbon dioxide generation, which are the disadvantages of the Haber-Bosch method, which is a conventional ammonia production method. When doped with a metal, it was found that nitrogen in the air can be synthesized into ammonia even at a relatively low temperature (100° C. or less) and atmospheric pressure, thereby completing the present invention.

The catalyst for low-temperature synthesis of ammonia according to the present invention may have the form of a metal nitride as shown in Equation 1 below.

[Equation 1]

M _2-x R _x Si _y N _z

In the present invention, x means the number of rare earth metal (lanthanide-based metal) atoms for preparing the catalyst, wherein x may be affected by the number of metal atoms other than the rare earth metal, and x is 0 or more; It is an integer of 2 or less.

For example, in the catalyst, when R is 0.7, M becomes 1.3, and when R is 1, M is equal to 1, and thus has a partial or total substitution relationship with each other. However, as described above, since x includes 0 and 2, either one of M and R must be included, but one of the two may not be included.

As described above, x is an integer of 0 or more and 2 or less, and more preferably 0.001≤x≤0.5. When x is out of the above range, the crystal structure collapses, so that it cannot serve as a catalyst and the reliability of the catalyst is deteriorated.

In Equation 1, M is a metal atom other than the rare earth metal, and M may be, for example, any one element selected from magnesium, calcium, strontium, and barium. Among them, ammonia including calcium, strontium and barium It is preferable because the synthetic effect is high.

In the present invention, R is a transition metal atom, for example, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, nickel, iron, molar. It is any one element selected from lybdenum and tungsten, and among them, europium, erbium, iron, molybdenum, and tungsten are preferable because of their high ammonia synthesis effect.

The transition metal serves to facilitate ammonia synthesis by lowering the energy required to separate the N≡N bond of the nitrogen molecule (N ₂ ) and the OH bond of the water molecule (H ₂ O) in the air.

In Equation 1, z means the number of atoms of nitrogen for preparing the catalyst, wherein z may be affected by the number of Group 2 elements and silicon atoms, and z is 7 or more, 9 or less, more preferably It is preferably an integer in the range 7.5≤z≤8.5.

The nitrogen serves to temporarily combine with hydrogen atoms decomposed from water molecules during ammonia synthesis to form ammonia, and when nitrogen sites in the crystal structure are vacated due to the formed ammonia, nitrogen in the air fills these vacancies.

In Equation 1, as described above, x is an integer of 0 or more and 2 or less, and z is preferably 7 or more and less than 9, and more preferably x and z are 0.001≤x≤0.5, 7.5≤z, respectively. ≤8.5 is preferred.

The catalyst in the present invention is not limited to the preparation method, and may be prepared by any of numerous methods of catalyst preparation known to those skilled in the art. A typical manufacturing method is a method of forming a mixture of a group 2 metal halide, a transition metal oxide, silicon and a reducing agent material and then reacting it by combustion.

In the present invention, the Group 2 metal halide may be any one or more selected from the aforementioned magnesium halide, calcium halide, strontium halide and barium halide, and specifically, MgF ₂ , CaF ₂ , SrF ₂ , BaF ₂ , MgCl ₂ , CaCl ₂ , SrCl ₂ , BaCl ₂ , MgBr ₂ , CaBr ₂ , SrBr ₂ , BaBr ₂ , MgI ₂ , CaI ₂ , SrI ₂ and BaI ₂ may be any one selected from or a mixture of two or more.

In particular, the Group 2 metal halide reacts with the reducing agent to cause an exothermic reaction, and it is possible to form a nitride catalyst due to the heat generated during the reduction/nitriding reaction.

The transition metal oxide is La ₂ O ₃ , CeO ₂ , Pr ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O ₃ , NiO, Fe ₂ O ₃ , MoO ₃ and WO ₃ may be any one or a mixture of two or more selected from these At least one selected from Eu ₂ O ₃ , Er ₂ O ₃ , Fe ₂ O ₃ , MoO ₃ , and WO ₃ may be more preferable.

The silicon (Si) is for generating an exothermic reaction required in the combustion reaction, and may be a powdery particle having a particle size of 0.01 to 15 μm in order to cause a more active combustion reaction.

The reducing agent may be any one or a mixture of two or more selected from lithium azide (LiN ₃ ), sodium azide (NaN ₃ ), and potassium azide (KN ₃ ). The reducing agent can reduce Group 2 metal halides and transition metal oxides, and is converted into LiF, LiCl, NaF, NaCl, KF, and KCl after the combustion reaction, which can be removed by leaching using distilled water.

The reducing agent may be included in 1 to 20 moles based on 1 mole of the Group 2 metal halide. If it is out of the above range, the reduction reaction or leaching may not be performed well.

Although the composition ratio of the mixture is not limited, it is preferable to adjust the ratio within a range that satisfies the composition ratio of the above-mentioned catalyst. At this time, the precursor compound of each element may be added depending on the form and composition of the catalyst to be produced. In particular, It may be determined whether a transition metal compound or a Group 2 metal halide is added in addition to the essential silicon and nitrogen compounds.

For example, in Formula 1, when x is 0, the transition metal is not included, and when a metal catalyst having the above composition ratio is prepared, the composition ratio of the Group 2 metal compound is fixed to 2, and the composition ratio of the silicon compound and the nitrogen compound is Only the composition ratio may be included in the range of 4 to 6: 7 to 9, respectively.

Conversely, when x is 2, since the Group 2 metal is not included, when a metal catalyst having the above composition ratio is prepared, the composition ratio of the transition metal compound is fixed to 2, and only the composition ratio of the silicon compound and the nitrogen compound is 4 to 6: 7, respectively. to 9 may be included.

In addition, when both a transition metal and a Group 2 metal are included, the composition ratio of the Group 2 metal halide, transition metal oxide, silicon and reducing agent is preferably 0.001 to 2: 0.001 to 2: 4 to 6: 7 to 9. .

The mixing method is not limited, but mixing by a ball mill may be preferable for a quick process and uniform mixing.

The reaction mixture obtained by the mixing may be filled in a container to form pellets, and the container may be a cup, and the cup may be cylindrical or rectangular.

The cup may be prepared from various kinds of components such as paper, metal, or quartz, and the density of the obtained pellets is 0.7 to 2.0 g/cm ³ , preferably 0.9 to 1.2 g/cm ³ , which ignites during combustion reaction. And it is good that the combustion reaction is made smoothly, but is not necessarily limited thereto.

The pelletized reaction mixture may be ignited from a heat source to initiate a combustion reaction, and the heat source may be a heat source due to resistance of a metal wire.

The combustion process used in the present invention is preferably carried out under high-pressure conditions, and may be carried out in a high-pressure reactor under a nitrogen atmosphere. At this time, the reaction pressure of nitrogen may be 0.5 to 5 MPa, preferably 1 to 3 MPa.

The combustion reaction is a self-sustaining reaction. After the reaction is started by the ignition reaction, there is no need to supply an external heat source, and it can be reacted rapidly along the reaction raw material at a rate of 0.1 to 0.5 cm/sec. .

The nitride catalyst of the present invention can be obtained by washing and leaching the product after performing the combustion reaction.

For the washing, a conventional method may be used, and distilled water is preferably used, and washing may be performed one or more times.

For the leaching, a conventional method may be used, and hydrochloric acid or sulfuric acid solution is preferably used in order to prevent a decrease in the synthesis efficiency of the prepared transnitride catalyst due to impurities.

The present invention may include a method for synthesizing ammonia using the nitride catalyst for low-temperature synthesis of ammonia prepared as described above. In this case, the method for synthesizing ammonia is

a1) preparing a slurry by mixing a catalyst for low-temperature synthesis of ammonia prepared by the above method with distilled water;

b1) injecting any one or a plurality of gases selected from nitrogen, hydrogen, air and water vapor into the slurry into the reactor; and

c1) heating the reactor to a temperature of 30 to 100° C. for a while;

include, or

a2) injecting a catalyst for low-temperature synthesis of ammonia into a reactor;

b2) injecting any one or a plurality of gases selected from nitrogen, hydrogen, air and water vapor into the reactor into the reactor; and

c2) heating the reactor to a temperature of 30 to 100 °C;

may include.

The ammonia production methods are basically the same as mixing a catalyst, water, and air in a reactor and heating it to a low temperature of 100° C. or less, and it is only the difference between mixing the catalyst and water first or mixing the water and air first. , there is no difference in the yield of ammonia no matter which method is applied.

The ammonia synthesis mechanism of the catalyst for ammonia synthesis according to the present invention can be explained in two ways. First, when a large number of water molecules come into contact with the catalyst, the nitrogen atom in the crystal structure of the catalyst is temporarily combined with three hydrogen atoms of the water molecule to form ammonia (NH ₃ ) and hydroxide ions (OH ^- ). The formed ammonia is separated from the catalyst and nitrogen atom vacancies are created in the catalyst. At this time, the adjacent transition metal atom separates the bond of the nitrogen molecule adsorbed to the catalyst from the air, and the separated nitrogen atom is filled in the vacancy. In this way, the catalyst returns to its original state and repeats the same process to produce ammonia.

Another mechanism is that nitrogen molecules are adsorbed to transition metal atoms in the crystal structure of the catalyst when the catalyst and air first come into contact. At this time, when the transition metal atom separates the bonds of nitrogen molecules and takes nitrogen atoms one by one, the nitrogen atoms combine with hydrogen atoms of water molecules to form ammonia (NH ₃ ) and hydroxide ions (OH ^- ). When the ammonia thus produced is separated from the catalyst, the catalyst can return to its original state and form ammonia by combining with other nitrogen molecules.

The above reaction starts immediately when nitrogen or water molecules in the air come into contact with the catalyst, and since temperature or pressure does not affect the activation of the catalyst, ammonia can be synthesized even at low temperature or atmospheric pressure. . However, as described above, since the number of times of contact between the nitrogen molecules and the catalyst is directly related to the yield of ammonia, it is necessary to heat the nitrogen molecules to a certain temperature or more to activate the movement of the nitrogen molecules.

As described above, in the present invention, the water provides hydrogen necessary for synthesizing ammonia, and air acts as a source of nitrogen, and separately corresponds to an ammonia source such as nitrogen, hydrogen, and water vapor so as to promote the reaction if necessary. The gas may be further mixed and injected into the reactor.

At this time, the mixing ratio of each composition is not limited in the method for synthesizing ammonia, and there is no upper limit for water or air compared to the catalyst. However, since the synthesis yield of ammonia increases when nitrogen is excessively supplied, the composition ratio of water and air is preferably 1 to 3:1. It is possible to reduce the unreacted composition in the above range, and it is possible to prevent the generated ammonia from being dissolved in water.

In the present invention, in the method for synthesizing ammonia, it is preferable to promote the reaction by heating for a predetermined time after the above-described compositions are introduced into the reactor. At this time, the heating temperature is not limited, but heating at a temperature of 30 to 100° C. is preferable in terms of energy saving.

The catalyst according to the present invention contains a metal compound including a transition metal as a main component, so that a large amount of ammonia is synthesized at a much lower temperature or under low energy than the conventional Haber-Bosch process or electrochemical synthesis method. This is possible, and at the same time, it has the advantage of synthesizing environmentally friendly ammonia that does not generate impurities such as carbon dioxide using water and air.

In addition, it consumes much less energy compared to the electrical synthesis method, and since it does not use an electrode, there is no concern about corrosion and the generation of additional impurities can be suppressed.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples and comparative examples are only examples for explaining the present invention, and the present invention is not limited to the following examples.

(Example 1)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.93: 0.07: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 30° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 2)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.93: 0.07: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 40°C to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 3)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.93: 0.07: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 4)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.93: 0.07: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 70° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 5)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.95: 0.05: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 6)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.97: 0.03: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 7)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of 1.99: 0.01: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 8)

Strontium chloride (SrCl ₂ , Daejeong Hwageum), silicon (Si, Samjeon Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwageum, 255S0074) powder was weighed at a molar ratio of 2.0: 5.0: 4.0, and then zirconia balls was mixed in a 1/2 weight ratio of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 9)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), iron oxide (Fe ₂ O ₃ , Alfa Aesar), silicon (Si, Samjeon Chemical, S2381), sodium azide (NaN ₃ , Daejeong Hwaeum, 255S0074) powder was 1.97: After weighing at a molar ratio of 0.03:5.0:4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was put into a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 10)

1.97 strontium chloride (SrCl ₂ , Daejung Hwaeum), samarium oxide (Sm ₂ O ₃ , Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejung Hwaeum, 255S0074) powder After weighing at a molar ratio of : 0.03: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was placed in a reactor (3L) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 11)

Strontium chloride (SrCl ₂ , Daejung Hwaeum), nickel oxide (NiO, Alfa Aesar), silicon (Si, Samchun Chemical, S2381), sodium azide (NaN ₃ , Daejeonghwageum, 255S0074) powder 1.97: 0.03: After weighing at a molar ratio of 5.0:4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was put into a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

(Example 12)

Barium chloride (BaCl ₂ , Daejeong Hwaeum), eurobium oxide (Eu ₂ O ₃ , Alfa Aesar), silicon (Si, Samjeon Chemical, S2381), sodium azide (NaN ₃ , Daejeong Hwageum, 255S0074) powder After weighing at a molar ratio of 1.97: 0.03: 5.0: 4.0, zirconia balls were mixed at a weight ratio of 1/2 of the raw material and mixed with a ball mill for 24 hours. The mixture was put into a high-purity alumina refractory container and laminated under pressure at 5 Mpa, put into a reactor, and the purge process of filling and vacuuming nitrogen gas was repeated three times, and then the inside of the reactor was filled with nitrogen gas of 20 atm and maintained. . The powder was synthesized by igniting the stacked raw materials using a hot wire to cause a combustion reaction. After washing the synthesized powder twice with water, it was mixed with an HCl solution of pH 1 and stirred for 2 hours, and then the powder was separated and recovered and washed with water. The recovered powder was dried at 100° C. for 2 hours to prepare a nitride catalyst.

1 g of the prepared catalyst powder was mixed with 2 g of distilled water to make a slurry. The prepared slurry was put into a reactor (3ℓ) and heated to 50° C. to incubate ammonia, and the degree of ammonia production was confirmed by measuring UV-vis spectrum using the indophenol method.

1 is an ammonia synthesis result according to Example 1, Example 2, Example 3 and Example 4. From the above results, it was confirmed that the ammonia synthesis efficiency increased as the temperature increased.

Figure 2 is the ammonia synthesis result according to Example 3, Example 5, Example 6 Example 7 and Example 8 at 50 ℃. As shown in the above results, it can be seen that the synthesis efficiency of ammonia varies according to the doping amount of the transition metal. In particular, it can be seen that the ammonia synthesis efficiency is the highest when 0.03 moles of europium is doped as in Example 6.

3 is an ammonia synthesis result according to Example 6, Example 9, Example 10 Example 11 and Example 12 at 50 ℃. As shown in the above results, it can be seen that the synthesis efficiency of ammonia varies depending on the type of transition metal. In particular, as in Example 6, it can be seen that the nitride doped with eurobium has the highest ammonia synthesis efficiency, and the iron of Example 9 It can be seen that the similar efficiency is also shown when doping.

In the above, preferred embodiments of the present invention have been described, but the scope of the present invention is not limited to the specific embodiments as described above, and those of ordinary skill in the art are appropriate within the scope described in the claims of the present invention. it will be possible to change

Claims (7)

A nitride catalyst for low-temperature synthesis of ammonia having the composition of Formula 1 below.
[Equation 1]
M _2-x R _x Si _y N _z
(In Equation 1 above,
M is any one element selected from magnesium, calcium, strontium and barium,
R is any one element selected from lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, nickel, iron, molybdenum and tungsten,
0≤x≤2,
4≤y≤6,
7≤z≤9.)
The method of claim 1,
Wherein M is a nitride catalyst for low-temperature synthesis of ammonia, characterized in that any one selected from calcium, strontium and barium.
The method of claim 1,
Wherein R is a nitride catalyst for low-temperature synthesis of ammonia, characterized in that any one element selected from europium, erbium, iron, molybdenum and tungsten.
The method of claim 1,
Wherein x is a nitride catalyst for low-temperature synthesis of ammonia, characterized in that 0.001≤x≤0.5.
The method of claim 1,
The z is a nitride catalyst for low-temperature synthesis of ammonia, characterized in that 7.5≤z≤8.5.
a1) preparing a slurry by mixing the catalyst for low-temperature synthesis of ammonia according to any one of claims 1 to 6 with distilled water;
b1) injecting any one or a plurality of gases selected from nitrogen, hydrogen, air and water vapor into the slurry into the reactor; and
c1) heating the reactor to a temperature of 30 to 100 °C;
A low-temperature synthesis method of ammonia from water and air using a nitride catalyst, comprising:
a2) injecting a catalyst for low-temperature synthesis of ammonia according to any one of claims 1 to 6 into the reactor;
b2) injecting any one or a plurality of gases selected from nitrogen, hydrogen, air and water vapor into the reactor into the reactor; and
c2) heating the reactor to a temperature of 30 to 100 °C;
A low-temperature synthesis method of ammonia from water and air using a nitride catalyst, comprising:

Images