KR20210058578A - Catalyst for CO2 hydrogenation to produce hydrocarbon compounds and preparation method thereof - Google Patents

Abstract

The present invention relates to a technology capable of producing a hydrocarbon compound by mediating a hydrogenation reaction of carbon dioxide, and more specifically, to: a reduction catalyst for carbon dioxide capable of producing a hydrocarbon compound having one or more carbon atoms by hydrogenating carbon dioxide under conditions in which hydrogen flows; a method for producing the reduction catalyst; and a method for producing a hydrocarbon compound using the reduction catalyst.

Description

A carbon dioxide reduction catalyst, a method for preparing the reduction catalyst, and a method for preparing a hydrocarbon compound using the reduction catalyst {Catalyst for CO2 hydrogenation to produce hydrocarbon compounds and preparation method thereof}

The present invention relates to a technology capable of producing a hydrocarbon compound by mediating a hydrogenation reaction of carbon dioxide, and more specifically, a carbon dioxide capable of producing a hydrocarbon compound having one or more carbons by hydrogenating carbon dioxide under conditions of flowing hydrogen. It relates to a reduction catalyst, a method for preparing the reduction catalyst, and a method for preparing a hydrocarbon compound using the reduction catalyst.

Carbon dioxide, as a representative global warming gas, is a gas that desperately needs to reduce its concentration in the atmosphere. As a result of the efforts, research for carbon capture, utilization and storage (CCUS) is being actively conducted. Carbon dioxide is a molecule in which two oxygens are bonded to carbon each with a double bond, and it is thermodynamically stable and chemically inactive, so it requires a large amount of energy to be supplied for the conversion reaction. Therefore, it is essential to develop a catalyst to increase the conversion rate of carbon dioxide beyond the thermodynamic limit.

As a conversion reaction of carbon dioxide, a reverse water-gas shift (RWGS) reaction is known, and through the above reaction, carbon dioxide can be converted into carbon monoxide and water by reacting with hydrogen. The reversible gas change reaction is an endothermic reaction (ΔH = +9 kcal/mol) and requires a high temperature reaction condition (generally 300°C or higher). Carbon monoxide, a product of the reversible gas change reaction, is more reactive than carbon dioxide, so it is easy to convert to other substances and is typically used as a reactant in the Fischer-Tropsch reaction for the production of fuels and refined chemicals, the methanol synthesis reaction and the methane synthesis reaction. I can. As described above, carbon monoxide is easily converted to other substances, and is thus reported as the most economical substance among carbon dioxide conversion reaction products.

In Germany in the 1920s, Franz Fischer and Hans Tropsch developed a carbon monoxide conversion process through the Fischer-Tropsch (FT) reaction, and through this, hydrocarbon fuels that could be used as gasoline and diesel could be produced and used as fuel. The FT industrial plant, first operated in 1936, produced more than 1 million tonnes of gasoline and diesel liquid fuels per year using coal until the 1940s. Effective metals used in the FT reaction include Ni, Fe, Co, and Ru. Ni has too much methane selectivity, which is a problem, and Ru is too expensive, so Fe and Co-based catalysts are mainly used in the FT reaction. Co-based catalysts have a disadvantage that they are 200 times more expensive than Fe-based catalysts, but have the advantages of high activity, long life, low carbon dioxide production, and high yield of liquid paraffinic hydrocarbons. Syngas containing a large amount of carbon dioxide is reported to have a problem of lowering the activity, and there is a problem of producing a large amount of methane at high temperatures, so it can be used only as a low-temperature catalyst. Due to its high cost, it must be well dispersed on a stable support having a high surface area such as alumina, silica, and titania, and a small amount of noble metal cocatalyst such as Pt, Ru, and Re is additionally added. The Fe-based catalyst has a low catalyst price, a higher reaction temperature than Co, and has high activity and a high yield of olefin-based hydrocarbon products with a high octane number. Since the hydrocarbon obtained through the FT reaction does not contain sulfur, it is possible to reduce the knocking phenomenon of the internal combustion engine with little adverse effect on the human body and the environment.

Accordingly, there is a need to develop a new carbon dioxide reduction catalyst that solves the above-described problems.

Patent Publication No. 10-2016-0133490

As a result of a number of studies, the present inventors completed the present invention by developing a carbon dioxide reduction catalyst containing a metal oxide of a spinel structure having mesopores that can act as a catalyst in the hydrogenation reaction of carbon dioxide.

Accordingly, an object of the present invention is a carbon dioxide reduction catalyst capable of increasing the conversion rate in the hydrogenation reaction of carbon dioxide, as well as producing a hydrocarbon compound having a high industrial use value of two or more carbons with high selectivity, and a method for producing a hydrocarbon compound using the reduction catalyst. Is to provide.

Another object of the present invention is to provide a method for producing a carbon dioxide reduction catalyst that is very simple and can be economically manufactured in large quantities at a time, and thus has a high industrial value.

Another object of the present invention is a liquid fuel that does not contain any impurities to be removed, such as sulfur and metal, which are inevitably generated when producing hydrocarbon-based liquid fuel materials by refining crude oil, and can be utilized as gasoline using a carbon dioxide reduction catalyst. It is to provide a hydrocarbon compound as a compound and a method for producing the same.

The object of the present invention is not limited to the above-mentioned object, and even if not explicitly mentioned, the object of the invention that one of ordinary skill in the art can recognize from the description of the detailed description of the invention to be described later may naturally be included. .

In order to achieve the object of the present invention described above, the present invention provides a carbon dioxide reduction catalyst comprising a spinel structure metal oxide having a skeleton consisting of a divalent metal and a trivalent metal and having mesopores in the range of 2 to 50 nm. do.

In a preferred embodiment, the spinel-structured metal oxide has a BET specific surface area of 50 to 200 m ² /g, and a volume of the mesopores of 0.13 to 0.47 mL/g.

In a preferred embodiment, the divalent metal is selected from the group consisting of copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni), manganese (Mn), and magnesium (Mg). And the trivalent metal is at least one selected from the group consisting of aluminum (Al), scandium (Sc), chromium (Cr), iron (Fe), and cobalt (Co).

In a preferred embodiment, the metal oxide of the spinel structure is copper-aluminum spinel (CuAl ₂ O ₄ ), zinc-aluminum spinel (ZnAl ₂ O ₄ ), cobalt-aluminum spinel (CoAl ₂ O ₄ ), magnesium-aluminum spinel It is any one selected from the group consisting of (MgAl ₂ O _{4 ).}

In a preferred embodiment, at least one of a monovalent metal and a divalent metal is supported on the mesopores formed in the spinel-structured metal oxide or is coated on the surface of the spinel-structured metal oxide to form an accelerating layer.

In a preferred embodiment, the monovalent metal contained in the promotion layer is 0.5 to 10% by weight, and the divalent metal is 9 to 50% by weight based on the total weight of the catalyst.

In a preferred embodiment, the monovalent metal is at least one selected from alkali metals, and the divalent metal is copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni). , Manganese (Mn), magnesium (Mg) is any one or more selected from the group consisting of.

In addition, the present invention comprises the steps of dissolving and dispersing a divalent metal precursor and a trivalent metal precursor in a solvent, respectively; Gradually adding and mixing the divalent metal precursor dispersion to the trivalent metal precursor dispersion; Adjusting pH by adding a basic solution to the mixed dispersion; Removing the solvent contained in the mixed dispersion; And firing the solid product remaining after the solvent is removed to obtain a metal oxide having a spinel structure. It provides a carbon dioxide reduction catalyst manufacturing method comprising a.

In a preferred embodiment, the pH is adjusted to 9 to 10.

In a preferred embodiment, the step of removing the solvent comprises filtering the solvent from the mixed dispersion; And drying the solid product remaining after filtering.

In a preferred embodiment, the firing treatment is performed at 700 to 900°C for 2 to 6 hours.

In a preferred embodiment, the step of forming an accelerating layer on the spinel-structured metal oxide; further includes.

In a preferred embodiment, the forming of the acceleration layer comprises dissolving and dispersing the metal oxide of the spinel structure and at least one metal precursor of the monovalent metal precursor and the divalent metal precursor forming the acceleration layer in a solvent. ; Removing the solvent contained in the dispersion; And calcining the remaining solid product after the solvent is removed.

In a preferred embodiment, the firing is performed at 500 to 600° C. for 2 to 6 hours.

In a preferred embodiment, the monovalent metal contained in the promotion layer is 0.5 to 10% by weight, and the divalent metal is 9 to 50% by weight based on the total weight of the catalyst.

In addition, the present invention comprises the steps of pre-treating any one of the above-described carbon dioxide reduction catalyst or the carbon dioxide reduction catalyst prepared by any one of the above-described manufacturing methods in a continuous flow fixed bed reactor; Adjusting to maintain a constant pressure by injecting a mixed gas including carbon dioxide and hydrogen into the reactor after the pretreatment; Adjusting the temperature of the reactor controlled by the constant pressure to a constant temperature; And inducing a hydrogenation reaction of carbon dioxide by flowing the mixed gas at a constant flow rate to a reactor controlled at a constant pressure and a constant temperature.

In a preferred embodiment, the constant pressure is 20 bar or more and the constant temperature is 250 to 500°C.

In a preferred embodiment, the volume ratio of carbon dioxide and hydrogen contained in the mixed gas is 1:2 to 1:5.

In a preferred embodiment, the mixed gas further contains an inert gas less than the amount of carbon dioxide.

In a preferred embodiment, the hydrocarbon compound includes a compound having 1 to 20 carbon atoms.

In a preferred embodiment, when the carbon dioxide reduction catalyst is a copper-aluminum spinel (CuAl ₂ O ₄ ) in which an accelerating layer containing potassium (K) and iron (Fe) is formed, the hydrogenation reaction of carbon dioxide contained in the mixed gas The conversion rate through is 40% or more, and the selectivity of a hydrocarbon compound having 2 or more carbon atoms is 30% or more.

In a preferred embodiment, the physicochemical properties of the produced hydrocarbon compound may be controlled by adjusting the content of potassium (K) and iron (Fe) included in the carbon dioxide reduction catalyst.

In addition, the present invention provides a hydrocarbon compound, characterized in that obtained by the above-described production method.

According to the above-described carbon dioxide reduction catalyst of the present invention and the method for producing a hydrocarbon compound using the reduction catalyst, it is possible to increase the conversion rate in the hydrogenation reaction of carbon dioxide, as well as to produce a hydrocarbon compound having a high industrial utility value of two or more carbons with high selectivity. .

In addition, according to the method of manufacturing a carbon dioxide reduction catalyst of the present invention, it is very simple and can be economically manufactured in a large amount at a time, so that the industrial application value is high.

In addition, according to the hydrocarbon compound and its manufacturing method of the present invention, gasoline using a carbon dioxide reduction catalyst does not contain any impurities to be removed, such as sulfur or metal, which are inevitably generated when crude oil is purified to produce hydrocarbon-based liquid fuel materials. It can provide liquid fuel compounds that can be used as.

These technical effects of the present invention are not limited only to the ranges mentioned above, and even if not explicitly mentioned, the effects of the invention that can be recognized by those of ordinary skill in the art from the description of specific details for the implementation of the invention described later are also Of course it is included.

1 is an X-ray diffraction pattern result of _{commercially available magnesium spinel (MgAl 2} O ₄ ) with carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention.
2 is a nitrogen adsorption isotherm of the carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention and commercially sold magnesium spinel (MgAl ₂ O _{4 ).}
Figure 3 is a dispersion diagram showing the size of pores using the BJH (Barrett-Joyner-Halenda) analysis method of carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention and commercially sold magnesium spinel (MgAl ₂ O ₄₎ to be.
Figure 4 is a result of measuring the surface basicity of the spinel structure using carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention and _{a temperature-raising desorption method using carbon dioxide of commercially sold magnesium spinel (MgAl 2} O ₄₎ to be.
5 is an electron transmission microscope image of a carbon dioxide reduction catalyst synthesized according to an embodiment of the present invention and a commercially available magnesium spinel (MgAl ₂ O _{4 ).}
6 is a result of analyzing an X-ray diffraction pattern of a carbon dioxide reduction catalyst synthesized according to another embodiment of the present invention.
Figure 7 is a reaction using a carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention and commercially sold magnesium spinel (MgAl ₂ O ₄ ) as a catalyst for the hydrogenation conversion reaction of carbon dioxide, and then gas chromatography is used. This is the result of analysis.
8 is an analysis result of gas chromatography equipped with a flame ionization detector after a catalytic conversion reaction of carbon dioxide to gasoline-based hydrocarbons using a carbon dioxide reduction catalyst synthesized according to another embodiment of the present invention.
9 is a result of hydrogenation conversion reaction of carbon dioxide of catalysts in which iron is supported in various amounts on a copper-aluminum spinel and a copper-aluminum spinel among carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention.
10 is a result of hydrogenation conversion reaction of carbon dioxide of catalysts in which iron and potassium are supported in various amounts on copper-aluminum spinel among carbon dioxide reduction catalysts synthesized according to an embodiment of the present invention.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the description of the invention, but one or more other It is to be understood that it does not preclude the presence or addition of features, numbers, steps, actions, components, parts, or combinations thereof.

Terms such as first and second may be used to describe various constituent elements, but the constituent elements should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

Unless otherwise defined, all terms used herein including technical or scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present invention. Does not.

In interpreting the constituent elements, it is interpreted as including an error range even if there is no explicit description. In particular, when the terms "about", "substantially" and the like of degree are used, it may be interpreted as being used in or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented. .

In the case of a description of a temporal relationship, for example,'after','following','after','before', etc., when a temporal predecessor relationship is described,'right' or'direct' This includes cases that are not continuous unless this is used.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

However, the present invention is not limited to the embodiments described herein, and the same reference numerals denote the same components in different forms.

The technical feature of the present invention is that it has mesopores that can act as a catalyst during the hydrogenation reaction of carbon dioxide, thereby increasing the conversion rate in the hydrogenation reaction of carbon dioxide, as well as producing a hydrocarbon compound having a high industrial use value of two or more carbons with high selectivity. The present invention relates to a carbon dioxide reduction catalyst including a spinel structure metal oxide, a method for producing the same, and a method for producing a hydrocarbon compound using the reduction catalyst.

That is, Spinel is a _{crystalline metal oxide having the formula of AB 2} O ₄ , A is a group IIA metal or a transition metal in a +2 oxidation state, and B is a group IIIA metal or a transition metal in a +3 oxidation state. However, physicochemical properties such as electrostatic and magnetic are different depending on the elements that make up the crystal, and it is known to have basic properties on the surface of most crystals, and it is a crystalline inorganic substance that forms a densely stacked cubic lattice (CCP). As one type, it has excellent thermodynamic and structural stability and is stable to acids and bases, but it is not used as a catalyst for reducing carbon dioxide that mediates the hydrogenation reaction of carbon dioxide. In particular, unlike the known spinel-structured metal oxide, the spinel-structured metal oxide contained in the carbon dioxide reduction catalyst of the present invention can exhibit excellent catalytic activity by remarkably widening the surface area such as forming mesopores therein. to be.

Accordingly, the carbon dioxide reduction catalyst of the present invention includes a metal oxide having a spinel structure having a skeleton composed of a divalent metal and a trivalent metal and having mesopores in the range of 2 to 50 nm.

Here, the divalent metal is not limited as long as it is a metal in the +2 oxidation state, but as an embodiment, copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni), manganese ( It may be at least one selected from the group consisting of Mn) and magnesium (Mg). The trivalent metal is also not limited as long as it is a metal in the +3 oxidation state, but as an embodiment, it is selected from the group consisting of aluminum (Al), scandium (Sc), chromium (Cr), iron (Fe), and cobalt (Co). It can be any one or more.

As an embodiment, the metal oxide of the spinel structure included in the carbon dioxide reduction catalyst of the present invention is copper-aluminum spinel (CuAl ₂ O ₄ ), zinc-aluminum spinel (ZnAl ₂ O ₄ ), cobalt-aluminum spinel (CoAl ₂ O _{4 ).} ), magnesium-aluminum spinel (MgAl ₂ O ₄ ) It may be any one selected from the group consisting of.

The spinel-structured metal oxide contained in the carbon dioxide reduction catalyst of the present invention has a BET specific surface area of 50 ~ 200 m ² /g, and the volume of mesopores is 0.13 ~ 0.47 mL/g. Can be indicated.

In another embodiment, the carbon dioxide reduction catalyst of the present invention includes a metal oxide having a spinel structure having a skeleton consisting of a divalent metal and a trivalent metal and having mesopores in the range of 2 to 50 nm; And an accelerating layer formed by at least one of a monovalent metal and a divalent metal being supported on mesopores formed in the metal oxide of the spinel structure or coated on the surface of the metal oxide of the spinel structure.

In this case, the monovalent metal is at least one selected from alkali metals, and the divalent metal is copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni), manganese (Mn). , Magnesium (Mg) may be any one or more selected from the group consisting of, as an embodiment, the monovalent metal contained in the promotion layer is 0.5 to 10% by weight based on the total weight of the catalyst, and the divalent metal is 9 to 50 It may be weight percent. The contents of the monovalent metal and the divalent metal included in the facilitation layer were determined experimentally, and were determined to increase the conversion rate of carbon dioxide during hydrogenation of carbon dioxide or to have high selectivity for high molecular weight hydrocarbon compounds.

Next, the carbon dioxide reduction catalyst manufacturing method of the present invention comprises the steps of dissolving and dispersing a divalent metal precursor and a trivalent metal precursor in a solvent, respectively; Gradually adding and mixing the divalent metal precursor dispersion to the trivalent metal precursor dispersion; Adjusting pH by adding a basic solution to the mixed dispersion; Removing the solvent contained in the mixed dispersion; And firing the solid product remaining after the solvent is removed to obtain a metal oxide having a spinel structure. Includes. If necessary, forming an accelerating layer on the metal oxide of the spinel structure; may further include.

Here, the solvent used to disperse the divalent metal precursor and the trivalent metal precursor may be any one or more selected from the group consisting of water or alcohols (ethanol, isopropanol, etc.). The step of adjusting the pH is carried out by adjusting the pH to 9 to 10 in order to make the mixed dispersion in a weakly basic environment.When the pH is adjusted in this way, the divalent metal precursor and the trivalent metal precursor are bonded to form a spinel structure. Because it has the effect of enabling you to do it. Removing the solvent may include filtering the solvent in the mixed dispersion; And drying the solid product remaining after filtering; the drying step may be performed by applying heat to 80° C. or higher. The sintering treatment is carried out at 700 to 900°C for 2 to 6 hours, and such reaction conditions are determined by experimentally finding the conditions under which the spinel structure metal oxide is well formed.

The forming of the promoting layer may include dissolving and dispersing a metal oxide having a spinel structure and at least one metal precursor of a monovalent metal precursor and a divalent metal precursor forming the acceleration layer in a solvent; Removing the solvent contained in the dispersion; And calcining the remaining solid product after the solvent is removed. Here, the sintering treatment is performed at 500 to 600° C. for 2 to 6 hours. Since the spinel structure is already formed, a carbon dioxide reduction catalyst having an appropriate structure can be obtained even if it is performed at a lower temperature.

Next, the method for producing a hydrocarbon compound of the present invention comprises the steps of pre-treating any one of the above-described carbon dioxide reduction catalysts or the above-described carbon dioxide reduction catalysts prepared by any one of the above-described production methods in a continuous flow fixed bed reactor; Adjusting to maintain a constant pressure by injecting a mixed gas including carbon dioxide and hydrogen into the reactor after the pretreatment; Adjusting the temperature of the reactor controlled by the constant pressure to a constant temperature; And inducing a hydrogenation reaction of carbon dioxide by flowing the mixed gas at a constant flow rate to the reactor controlled at the constant pressure and the constant temperature.

Here, the constant pressure may be 20 bar or more, and the constant temperature may be 250 to 500°C. When the reaction conditions are out of range, there is a problem in that the conversion rate of carbon dioxide and the selectivity to the high molecular weight hydrocarbon compound are deteriorated. In addition, the volume ratio of carbon dioxide and hydrogen contained in the mixed gas may be 1:2 to 1:5, and if it is less than 1:2, the conversion rate of carbon dioxide is lowered, and if it exceeds 1:5, the selectivity for high molecular weight hydrocarbon compounds This is because it becomes lower. If necessary, the mixed gas may further contain an inert gas less than the content of carbon dioxide, and the inert gas is not limited as long as it is an inert gas such as helium or argon.

In addition, in the method for producing a hydrocarbon compound of the present invention, the physicochemical properties of the produced hydrocarbon compound can be controlled by adjusting the content of potassium (K) and iron (Fe) contained in the carbon dioxide reduction catalyst. When the catalyst is a copper-aluminum spinel (CuAl ₂ O ₄ ) in which a promoting layer containing potassium (K) and iron (Fe) is formed, the conversion rate through hydrogenation of carbon dioxide contained in the mixed gas is 40% or more, and carbon The selectivity of two or more hydrocarbon compounds may be 30% or more.

Next, the hydrocarbon compound of the present invention is prepared using a carbon dioxide reduction catalyst by the above-described manufacturing method, and includes a compound having 1 to 20 carbons, that is, methane that can be used as a natural gas fuel as well as two carbons. It may contain hydrocarbon compounds with high industrial value. In particular, hydrocarbon compounds having 5 or more carbons are liquid fuel compounds that can be used as gasoline and are of very high value in that they can obtain petroleum substitute fuels from carbon dioxide. Since the compounds do not contain any impurities, such as sulfur or metal, which must be removed when producing hydrocarbon-based liquid fuel materials by refining crude oil, there is no need for a separate impurity refining process, and the product has excellent economic value.

Example 1

1. Dissolving and dispersing a metal precursor in a solvent

80 g of isopropyl alcohol and 0.06 mol (12.255 g) of aluminum isopropoxide were placed in a 250 ml round bottom two-necked flask, stirred at 110° C. for 2 hours, and refluxed to obtain a clear solution of a trivalent metal precursor dispersion. In addition, 10 ml of distilled water and copper nitrate ㅇ2.5 hydrate (Cu(NO ₃ ) ₂ ㅇ2.5H ₂ O) 0.03 mol (6.977 g) were dissolved in a polypropylene (PP) bottle to obtain a divalent metal precursor dispersion.

2. Mixing step

The divalent metal precursor dispersion was slowly added to the trivalent metal precursor dispersion, using a syringe. In the mixing step, the mixture was stirred vigorously (1000 rpm) so as not to harden and refluxed for 3 hours.

3. Adjusting the pH

The refluxed mixed dispersion was cooled to room temperature, titrated (about 13 ml) with aqueous ammonia until the pH reached 9.5, and stirred for 3 hours.

4. Step of removing the solvent

The obtained solution was filtered, and the solid product obtained after filtration was dried at 100° C. for 12 hours.

5. Firing treatment to obtain spinel structure metal oxide

The dried solid product was calcined at 800° C. for 4 hours _{to synthesize a carbon dioxide reduction catalyst 1 [copper-aluminum spinel (CuAl 2} O ₄ )].

Example 2

Except that 0.03 mol (8.92 g) of zinc nitrate hexahydrate (Zn(NO ₃ ) ₂ ㅇ6H ₂ O) was used instead of 0.03 mol of copper nitrate ㅇ2.5 hydrate (Cu(NO ₃ ) ₂ ㅇ2.5H _{2 O),} In the same manner as in Example 1, a carbon dioxide reduction catalyst 2 [zinc-aluminum spinel (CuAl ₂ O ₄ )] was synthesized.

Example 3

Except that 0.03 mol (8.73 g) of cobalt nitrate (Co(NO ₃ ) ₂ ㅇ6H ₂ O) was used instead of 0.03 mol of copper nitrate ㅇ2.5 hydrate (Cu(NO ₃ ) ₂ ㅇ2.5H _{2 O).} In the same manner as in Example 1, a carbon dioxide reduction catalyst 3 [cobalt-aluminum spinel (CoAl ₂ O ₄ )] was synthesized.

Example 4

Copper nitrate ㅇ2.5 hydrate (Cu(NO ₃ ) ₂ ㅇ2.5H ₂ O) instead of 0.03 mol, except that 0.03 mol (7.69 g) of magnesium nitrate hexa hydrate (Mg(NO ₃ ) ₂ ㅇ6H _{2 O) was used.} In the same manner as in Example 1, a carbon dioxide reduction catalyst 4 [magnesium-aluminum spinel (MgAl ₂ O ₄ )] was synthesized.

Example 5

1. Dispersing a spinel structure metal oxide, a monovalent metal precursor, and a divalent metal precursor

Put 30 ml of distilled water in a 100 ml round bottom flask, and the copper-aluminum spinel (CuAl ₂ O ₄ ) synthesized in Example 1 1 g, iron nitrate 9 hydrate (Fe(NO ₃ ) ₃ ㅇ9H ₂ O) 2.17 g, potassium nitrate ( After adding KNO ₃ ) 0.26g, the mixture was stirred at room temperature for about 1 hour.

2. Step of removing the solvent contained in the dispersion

After stirring, the solvent was blown away using a rotary evaporator, and dried in an oven at 100° C. for 12 hours.

3. Steps to be plasticized

The dried solid product was calcined at 550° C. for 4 hours to form a catalyst (22Fe7K/CuAl) with a promotion layer consisting of 22 wt% Fe and 7 wt% K in a _{carbon dioxide reduction catalyst 5 [copper-aluminum spinel (CuAl 2} O _{4 ). 2} O ₄ )] was synthesized.

Example 6

_{Except that potassium nitrate (KNO 3} ) was used in the same manner as in Example 5, except that 0.1 g of potassium nitrate (KNO 3) was used to form the promoting layer, _{the carbon dioxide reduction catalyst 6 [copper-aluminum spinel (CuAl 2} O ₄ ) 22 _{A catalyst (22Fe3K/CuAl 2} O ₄ ) on which an accelerating layer composed of wt% Fe and 3 wt% K was formed was synthesized.

Example 7

_{Except that potassium nitrate (KNO 3} ) was used in the same manner as in Example 5, except that 0.026 g of potassium nitrate (KNO 3) was used to form the promotion layer, _{the carbon dioxide reduction catalyst 7 [copper-aluminum spinel (CuAl 2} O ₄ ) 22 _{A catalyst (22Fe0.8K/CuAl 2} O ₄ ) on which an accelerating layer composed of wt% Fe and 0.8 wt% K was formed was synthesized.

Example 8

The same method as in Example 5 was used, except that only 7.23 g of iron nitrate 9 hydrate (Fe(NO ₃ ) ₃ ㅇ9H ₂ O) was used to form the promoting layer, and potassium nitrate (KNO _{3) was not used.} By performing a carbon dioxide reduction catalyst 8 [copper-aluminum spinel (CuAl ₂ O _{4 ), a catalyst (50Fe/CuAl 2} O ₄ ) in which a promoting layer composed of 50 wt% Fe was formed] was synthesized.

Example 9

_{Except that potassium nitrate (KNO 3} ) was not used to form the promoting layer, a carbon dioxide reduction catalyst 9 (copper-aluminum spinel (CuAl ₂ O ₄ ) in 22 wt% Fe was performed in the same manner as in Example 5), except that potassium nitrate (KNO 3) was not used. _{A catalyst (22Fe/CuAl 2} O ₄ ) with a configured acceleration layer formed thereon was synthesized.

Example 10

The same method as in Example 5 was used except that 0.72 g of iron nitrate 9 hydrate (Fe(NO ₃ ) ₃ ㅇ9H ₂ O) was used to form the promoting layer, and potassium nitrate (KNO _{3) was not used.} By performing a carbon dioxide reduction catalyst 10 [copper-aluminum spinel (CuAl ₂ O _{4 ), a catalyst (9Fe/CuAl 2} O ₄ ) in which an accelerating layer composed of 9wt% Fe was formed] was synthesized.

Experimental Example 1

X-ray diffraction patterns of the carbon dioxide reduction catalysts 1 to 4 obtained in Examples 1 to 4 and commercially sold magnesium spinel (MgAl ₂ O ₄ ) were measured, and the results are shown in FIG. 1.

From FIG. 1, it can be seen that the magnesium-aluminum spinel synthesized in the present invention is synthesized in a nanocrystalline structure, as the magnesium-aluminum spinel obtained in the embodiment of the present invention has a wider peak width than that of the commercially available magnesium spinel. I can.

Experimental Example 2

The nitrogen adsorption isotherms of the carbon dioxide reduction catalysts 1 to 4 obtained in Examples 1 to 4 and commercially sold magnesium spinel (MgAl ₂ O ₄ ) were observed, and the results are shown in FIG. 2.

As a result of the analysis as shown in FIG. 2, it can be seen that the spinel-structured metal oxide synthesized in the present invention has a mesoporous structure and is synthesized by looking at the remodeling that rises in the range of 0.4-0.9 relative pressure. In particular, magnesium-aluminum spinel had a higher amount of nitrogen adsorbed inside mesopores than commercially sold magnesium spinel, but the BET surface area and pore volume of the magnesium-aluminum spinel synthesized in the present invention were compared with commercial magnesium spinel. Then it can be seen that it is about 3 times (199 vs 77 m ² g ^-1 ).

Experimental Example 3

The carbon dioxide reduction catalysts 1 to 4 obtained in Examples 1 to 4 and commercially sold magnesium spinel (MgAl ₂ O ₄ ) were analyzed for pore size using BJH (Barrett-Joyner-Halenda) analysis, and the resultant The degree of dispersion is shown in FIG. 3.

As shown in Figure 3, as a result of the analysis, it can be seen that the spinels, which are carbon dioxide reduction catalysts 1 to 4 of the present invention, have an average pore size of 3.3 to 24.4 nm. However, it can be seen that the commercial magnesium spinel has almost no mesopores.

Experimental Example 4

The carbon dioxide reduction catalysts 1 to 4 obtained in Examples 1 to 4 and commercially sold magnesium spinel (MgAl ₂ O ₄ ) were subjected to an elevated temperature desorption method using carbon dioxide to measure the surface basicity of the spinel structure, and the The results are shown in Table 1 and FIG. 4.

As shown in Figure 4, as a result of the analysis, it was found that the copper-aluminum spinel, which has the largest amount of carbon dioxide desorbed at ^{high temperature (800 o C), has a strong basicity (123 mmol g -1} ), and thus interacts with carbon dioxide. I can.

In addition, from Table 1, the spinels, which are carbon dioxide reduction catalysts 1 to 4 of the present invention, all have mesopores of 2 to 50 nm, and in the case of the carbon dioxide reduction catalyst 4 magnesium spinel, a commercially available magnesium spinel (MgAl ₂ O ₄ (comm.) ), the surface area (S _BET ) is 3 times larger (199 m ² g ^-1 vs 77 m ² g ^-1 ), and the total pore volume is also 2 times larger (0.47 cm ³ g ^-1 vs 0.24 cm ³⁾ g ^-1 ) can be confirmed. The total number of basic points (B _T ) is almost similar (138.3 mmol g ^-1 vs 165.0 mmol g ^-1 ) can be confirmed, and in general, it can be seen that the carbon dioxide reduction catalyst 4 magnesium spinel has a weak basic point (B _W ^{) (98.0 mmol g -1} vs. 54.8 mmol g ^-1 ). Relatively, commercial magnesium spinel has more _{strong basic points (B S ).}

Experimental Example 5

The carbon dioxide reduction catalysts 1 to 4 obtained in Examples 1 to 4 and commercially sold magnesium spinel (MgAl ₂ O ₄ ) were observed with an electron transmission microscope, and the images are shown in FIG. 5.

As shown in FIG. 5, as a result of the analysis, it can be seen that the spinels of carbon dioxide reduction catalysts 1 to 4 form nanocrystals of different sizes and have a structure having mesopores between the crystals. On the other hand, it can be seen that the commercial magnesium spinel has almost no mesopores.

Experimental Example 6

The carbon dioxide reduction catalysts 1 to 4 obtained in Examples 1 to 4 and commercially sold magnesium spinel (MgAl ₂ O ₄ ) were observed with an electron transmission microscope, and the images are shown in FIG. 5.

As shown in FIG. 5, as a result of the analysis, it can be seen that the spinels of carbon dioxide reduction catalysts 1 to 4 form nanocrystals of different sizes and have a structure having mesopores between the crystals. On the other hand, it can be seen that the commercial magnesium spinel has almost no mesopores.

Experimental Example 7

The carbon dioxide reduction catalysts 5 to 10 and the carbon dioxide reduction catalyst 1 (CuAl ₂ O ₄ ) obtained in Examples 5 to 10 were analyzed through X-ray diffraction analysis, and the results are shown in FIG. 6.

6, the carbon dioxide reduction catalysts _{obtained through Examples 5 to 10 in the carbon dioxide reduction catalyst 1 (CuAl 2} O ₄ ) maintain the basic skeleton structure of copper-spinel, and are added as an accelerating layer. Depending on the amount of iron, the structure of iron can be identified in the X-ray diffraction pattern. In addition, even when potassium is added together as an accelerating layer, it can be seen that a peak appears in the X-ray diffraction pattern according to the weight of potassium.

Example 11

1. Pretreatment of the carbon dioxide reduction catalyst

After spreading glass wool in a continuous flow fixed bed reactor, 0.5 g of carbon dioxide reduction catalyst 1 in powder form and 1 g of sea sand are diluted and ^{reduced at 400 o} C for 4 hours while flowing argon (50 ml/min) and hydrogen (60 ml/min) at normal pressure. Made it.

2. Step of adjusting to maintain a constant pressure

After cooling to room temperature, a carbon dioxide mixed gas (21% _{CO 2 , 63% H 2} , 16% Ar) was filled and the pressure was adjusted to 20 bar.

3. Adjusting to maintain a constant temperature

The temperature of the reactor controlled to have a constant pressure was raised to a specific reaction temperature (300, 320, 350°C).

4. Step of inducing hydrogenation of carbon dioxide

Hydrocarbon compounds can be synthesized by inducing a hydrogenation reaction of carbon dioxide while flowing a mixed gas at a flow rate of 84 ml/min to a reactor controlled to have a constant pressure and a constant temperature.

Examples 12 to 20

A hydrocarbon compound was prepared in the same manner as in Example 11, except that carbon dioxide reduction catalysts 2 to 10 were used instead of carbon dioxide reduction catalyst 1, respectively.

Experimental Example 8

The gas obtained in Examples 11 to 14, i.e., a hydrocarbon compound, was continuously flowed through a gas chromatography equipped with a flame ionization detector and a thermal conductivity detector and analyzed, and the results are shown in Tables 2 and 7. At this time, the gas hourly space velocity (GHSV) is 10,080 (ml/g/h). In FIG. 7, the upper part is a graph showing the conversion rate of carbon dioxide and the selectivity to the product as a result of the catalytic reaction over time, and the lower part is a graph organized by averaging the upper graph.

As shown in Table 2 and FIG. 7, as a result of the reaction, the carbon monoxide reduction catalysts 1 to 4 mostly show carbon monoxide as the main product. It can be seen that the conversion rate is also higher than that of other spinels. However, unlike other spinels, in the case of cobalt-aluminum spinel, it can be confirmed that methane comes out as the main product.

Experimental Example 9

The gas obtained in Example 15, i.e., a hydrocarbon compound, was prepared by Agilent's GS-GASPRO column (30 m X 0.32 mm) and Supelco Analytical's 40/60 Carboxen-1000 metal packed column (5 ft X 1/8 in. X 2.1 mm). The separated compounds were separated by injection into the installed gas chromatography, and the separated compounds were calculated using the thermal conductivity detector and the flame ionization detector to calculate the conversion rate of carbon dioxide and the selectivity of the products. And analyzed and the results are shown in FIG. 8.

From FIG. 8, according to the method for producing a hydrocarbon compound of the present invention, a hydrocarbon compound having 5 or more carbon atoms, which is a range of gasoline-based hydrocarbons, is generated through a hydrogenation reaction of carbon dioxide using a carbon dioxide reduction catalyst from carbon dioxide and hydrogen. Can be seen.

Experimental Example 10

Example 11 [Use of carbon dioxide reduction catalyst 1 (CuAl ₂ O ₄ )], Example 20 [Use of carbon dioxide reduction catalyst 10 (9Fe/CuAl ₂ O ₄ )], Example 19 [Use of carbon dioxide reduction catalyst 9 (22Fe/CuAl ₂ O) ₄ ) Use] and Example 18 [Use of carbon dioxide reduction catalyst 8 (50Fe/CuAl ₂ O ₄ )] Except for using the gas obtained after the reaction, the conversion rate of carbon dioxide and the selectivity of products were calculated in the same manner as in Experimental Example 9 , The analysis results are shown in Table 3 and FIG. 9. In FIG. 9, the upper part is a graph showing the conversion rate of carbon dioxide and the selectivity to the product as a result of the catalytic reaction over time, and the lower part is a graph organized by averaging the upper graph.

As shown in Table 3 and FIG. 9, as a result of the reaction, it can be seen that the selectivity of the product shifted from carbon monoxide to the hydrocarbon region after supporting iron on the copper-aluminum spinel, and the conversion rate of carbon dioxide increased as the iron content increased. It can be seen that it increases. However, when comparing 22Fe/CuAl ₂ O ₄ and 50Fe/CuAl ₂ O ₄ , there was no obvious change in selectivity.

Experimental Example 11

Example 19 [Use of carbon dioxide reduction catalyst 9 (22Fe/CuAl ₂ O ₄ )], Example 17 [Use of carbon dioxide reduction catalyst 7 (22Fe0.8K/CuAl ₂ O ₄ )], Example 16 [Use of carbon dioxide reduction catalyst 6 (22Fe3K) /CuAl ₂ O ₄ ) use] and Example 15 [carbon dioxide reduction catalyst 5 (22Fe7K/CuAl ₂ O ₄ ) use], except that the gas obtained after the reaction was used, and the conversion rate of carbon dioxide and the products were Selectivity was calculated, and the analysis results are shown in Table 4 and FIG. 10. In FIG. 10, the upper part is a graph showing the conversion rate of carbon dioxide and the selectivity to the product as a result of the catalytic reaction over time, and the lower part is a graph organized by averaging the upper graph.

As shown in Table 4 and FIG. 10, as a result of the reaction, it can be observed that the selectivity of the product shifted from a normal-based hydrocarbon to a hydrocarbon having an isomer structure compared to a catalyst in which potassium was supported together with iron and then only iron was supported. It can be observed that as the content of potassium increases, the proportion of hydrocarbons having a heterogeneous structure increases compared to the normal series hydrocarbons. In addition, it can be observed that the conversion rate of carbon dioxide was also partially increased.

Although the present invention has been shown and described with a preferred embodiment as described above, it is not limited to the above-described embodiment, and within the scope of the spirit of the present invention, to those of ordinary skill in the art. Various changes and modifications will be possible.

Claims (23)

Carbon dioxide reduction catalyst comprising; a spinel structure metal oxide having a skeleton consisting of a divalent metal and a trivalent metal and having mesopores in the range of 2 to 50 nm.
The method of claim 1,
The spinel-structured metal oxide has a BET specific surface area of 50 to 200 m ² /g, and the volume of the mesopores is 0.13 to 0.47 mL/g.
The method of claim 1,
The divalent metal is at least one selected from the group consisting of copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni), manganese (Mn), and magnesium (Mg), The trivalent metal is a carbon dioxide reduction catalyst, characterized in that at least one selected from the group consisting of aluminum (Al), scandium (Sc), chromium (Cr), iron (Fe), and cobalt (Co).
The method of claim 3,
The metal oxide of the spinel structure is copper-aluminum spinel (CuAl ₂ O ₄ ), zinc-aluminum spinel (ZnAl ₂ O ₄ ), cobalt-aluminum spinel (CoAl ₂ O ₄ ), magnesium-aluminum spinel (MgAl ₂ O ₄ ) Carbon dioxide reduction catalyst, characterized in that any one selected from the group consisting of.
The method of claim 1,
At least one of a monovalent metal and a divalent metal is supported on the mesopores formed in the metal oxide of the spinel structure, or is formed by coating on the surface of the metal oxide of the spinel structure; carbon dioxide reduction catalyst further comprising a.
The method of claim 5,
A carbon dioxide reduction catalyst, characterized in that the monovalent metal contained in the promotion layer is 0.5 to 10% by weight based on the total weight of the catalyst, and the divalent metal is 9 to 50% by weight.
The method of claim 5,
The monovalent metal is at least one selected from alkali metals, and the divalent metal is copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni), manganese (Mn), Carbon dioxide reduction catalyst, characterized in that at least one selected from the group consisting of magnesium (Mg).
Dissolving and dispersing the divalent metal precursor and the trivalent metal precursor in a solvent, respectively;
Gradually adding and mixing the divalent metal precursor dispersion to the trivalent metal precursor dispersion;
Adjusting pH by adding a basic solution to the mixed dispersion;
Removing the solvent contained in the mixed dispersion; And
Firing the solid product remaining after the solvent is removed to obtain a metal oxide having a spinel structure; Carbon dioxide reduction catalyst manufacturing method comprising a.
The method of claim 8,
The carbon dioxide reduction catalyst manufacturing method, characterized in that the pH is adjusted to 9 to 10.
The method of claim 8,
Removing the solvent may include filtering the solvent from the mixed dispersion; And drying the solid product remaining after filtering.
The method of claim 8,
The sintering treatment is a carbon dioxide reduction catalyst manufacturing method, characterized in that the treatment for 2 to 6 hours at 700 to 900 ℃.
The method of claim 8,
Forming an accelerating layer on the spinel-structured metal oxide; carbon dioxide reduction catalyst manufacturing method further comprising a.
The method of claim 12,
The forming of the promotion layer may include dissolving and dispersing the metal oxide of the spinel structure and at least one metal precursor of a monovalent metal precursor and a divalent metal precursor forming the promotion layer in a solvent; Removing the solvent contained in the dispersion; And calcining the solid product remaining after the solvent is removed. The method of claim 12,
The calcining step is a carbon dioxide reduction catalyst manufacturing method, characterized in that the treatment is carried out at 500 to 600 ℃ for 2 to 6 hours.
The method of claim 12,
The monovalent metal contained in the accelerating layer is 0.5 to 10% by weight based on the total weight of the catalyst, and the divalent metal is 9 to 50% by weight.
Pre-treating the carbon dioxide reduction catalyst of any one of claims 1 to 7 or the carbon dioxide reduction catalyst prepared by the production method of any one of claims 8 to 15 in a continuous flow fixed bed reactor;
Adjusting to maintain a constant pressure by injecting a mixed gas including carbon dioxide and hydrogen into the reactor after the pretreatment;
Adjusting the temperature of the reactor controlled by the constant pressure to a constant temperature; And
Inducing a hydrogenation reaction of carbon dioxide by flowing the mixed gas into a reactor controlled at a constant pressure and a constant temperature at a constant flow rate.
The method of claim 16,
The method for producing a hydrocarbon compound, characterized in that the constant pressure is more than 20 bar and the constant temperature is 250 to 500 °C.
The method of claim 16,
The method for producing a hydrocarbon compound, characterized in that the volume ratio of carbon dioxide and hydrogen contained in the mixed gas is 1:2 to 1:5.
The method of claim 18,
The method for producing a hydrocarbon compound, wherein the mixed gas further contains an inert gas in an amount less than the amount of carbon dioxide.
The method of claim 16,
The hydrocarbon compound is a method for producing a hydrocarbon compound, characterized in that it contains a compound having 1 to 20 carbon atoms.
The method of claim 20,
When the carbon dioxide reduction catalyst is a copper-aluminum spinel (CuAl ₂ O ₄ ) in which an accelerating layer containing potassium (K) and iron (Fe) is formed, the conversion rate through hydrogenation of carbon dioxide contained in the mixed gas is 40% Above, and the selectivity of the hydrocarbon compound having 2 or more carbon atoms is 30% or more.
The method of claim 21,
A method for producing a hydrocarbon compound, characterized in that it is possible to control the physicochemical properties of the produced hydrocarbon compound by adjusting the content of potassium (K) and iron (Fe) contained in the carbon dioxide reduction catalyst.
Hydrocarbon compound, characterized in that obtained by the production method of claim 16.

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