KR20240166818A - Catalyst for hydrocarbon synthesis through carbon dioxide hydrogenation, method for preparing the same, and method for synthesizing hydrocarbon using the catalyst - Google Patents

Abstract

The present invention relates to a method for producing a catalyst for synthesizing hydrocarbon compounds through hydrogenation of carbon dioxide and a method for synthesizing hydrocarbons. More specifically, it is a synthesis method for controlling the selectivity of hydrocarbons by adding various promoters (Mn, Al, Zn) to a cobalt-based catalyst.

Description

Catalyst for hydrocarbon synthesis through carbon dioxide hydrogenation, method for preparing the same, and method for preparing hydrocarbons using the catalyst {CATALYST FOR HYDROCARBON SYNTHESIS THROUGH CARBON DIOXIDE HYDROGENATION, METHOD FOR PREPARING THE SAME, AND METHOD FOR SYNTHESIZING HYDROCARBON USING THE CATALYST}

The present invention relates to a catalyst for hydrocarbon synthesis through carbon dioxide hydrogenation, a method for producing the same, and a method for producing hydrocarbons using the catalyst. More specifically, the present invention relates to a catalyst for hydrocarbon synthesis through carbon dioxide hydrogenation, a method for producing the same, and a method for producing hydrocarbons using the catalyst, which enables easy conversion of carbon dioxide into hydrocarbons using a catalyst active in the reverse water gas shift reaction and the Fischer-Tropsch synthesis reaction.

Carbon dioxide is a representative global warming gas, accounting for 55% of global warming contributions. In an effort to reduce carbon dioxide, research on carbon capture, utilization, and storage (CCUS) is actively being conducted. Among these, technologies that hydrogenate carbon dioxide using a catalyst and then convert it into a high value-added chemical raw material are attracting attention. The reaction for synthesizing hydrocarbons from carbon dioxide proceeds in two stages: the reverse water gas shift reaction that hydrogenates carbon dioxide to carbon monoxide, and the Fischer-Tropsch synthesis (FTS) reaction that hydrogenates carbon monoxide to hydrocarbons. Hydrocarbons produced by the polymerization of carbon chains can be used as transportation fuels such as petroleum gas (C _2-4 ), gasoline (C _5-11 ), diesel (C _12-2 ), and wax (C ₂₁ +) (Journal of Catalysis 288 (2012) 104-114). They are a clean fuel that is attracting attention because they can store more energy than methane and are easier to transport than gaseous energy.

In the above Fischer-Tropsch reaction, a catalyst is an important element, and ruthenium (Ru), iron (Fe), and cobalt (Co) are known as catalysts. Ruthenium is the most active catalyst, but iron and cobalt, which are relatively inexpensive, are mainly used due to price issues.

Iron has the disadvantage of being active at high temperatures above 300℃, but it shows higher olefin selectivity than cobalt. On the other hand, cobalt-based catalysts have the disadvantage of being expensive compared to iron, but they have the advantage of being active at low temperatures of about 250℃, and they have the advantages of high activity, long life, low carbon dioxide production, and high production yield of liquid paraffin hydrocarbons. However, there is a problem that the activity is low in synthesis gas containing a large amount of carbon dioxide, and there is a problem that a large amount of methane is produced at high temperatures, so there is a problem that it can only be used as a low-temperature catalyst.

Hydrocarbon synthesis reaction through carbon dioxide hydrogenation can be operated at low temperatures, but it still requires overcoming the problems of low carbon dioxide conversion and high carbon monoxide and methane selectivity. Therefore, research is required to control the catalyst surface properties through appropriate reaction conditions and introduction of promoters.

Patent Publication No. 10-2020-0091656 (Publication Date: 2020.07.31)

The present invention aims to solve the problems of cobalt-based catalysts, which are low carbon dioxide conversion rate and high methane selectivity.

In order to achieve the above-mentioned purpose, the present invention provides a carbon dioxide reduction catalyst represented by the following chemical formula 1.

[Chemical Formula 1]

,

,

,

)CoMn _x Al _y Zn _z (

,

,

,

)

In a preferred embodiment, the catalyst may be characterized in that an active metal is supported on a mesoporous structural material.

In a preferred embodiment, the catalyst can be CoMn _x Al _0.5 (0.1≤x≤0.5) or CoMn _0.2 Zn _0.5 .

In a preferred embodiment, the catalyst may have an average surface area of 50 to 200 m ² /g.

In a preferred embodiment, the carrier may have an average pore size of 2 to 20 nm.

In addition, the present invention provides a method for producing a carbon dioxide reduction catalyst having a mesoporous structure, the method comprising: a step of producing a metal precursor mixture solution by dispersing a metal precursor in a solvent; a step of injecting the metal precursor mixture solution into a mesoporous structure material; a step of drying the mesoporous structure material and then calcining it, wherein the metal precursor further includes a manganese precursor, an aluminum precursor, or a zinc precursor in addition to a cobalt precursor; a step of stirring the composite metal oxide in an acidic or basic solution; a step of washing and filtering the acidic or basic solution, and then drying it; The present invention provides a method for producing a carbon dioxide reduction catalyst characterized in that it acts as a catalyst in the hydrogenation reaction of carbon dioxide.

In a preferred embodiment, the sintering treatment can be performed at a temperature of 450 to 650°C.

In a preferred embodiment, in the step of stirring the composite metal oxide in an acidic or basic solution, the acidic solution may be an HF aqueous solution.

In a preferred embodiment, in the step of putting the composite metal oxide into an acidic or basic solution and stirring, the basic solution may be a NaOH aqueous solution.

In a preferred embodiment, the acidic and basic solutions can be stirred at room temperature to 60°C.

In addition, the present invention provides a method for producing a hydrocarbon compound, comprising: a step of arranging any one of the carbon dioxide reduction catalysts described above or a carbon dioxide reduction catalyst produced by any one of the production methods described above inside a reactor; a step of supplying a reducing gas containing hydrogen gas and nitrogen gas into the reactor to perform reduction; and a step of supplying a reaction gas into the reactor to synthesize a hydrocarbon through hydrogenation of carbon dioxide.

In a preferred embodiment, the reactor is a Fischer-Tropsch fixed bed reactor and quartz wool may be placed inside the reactor.

In a preferred embodiment, the reducing gas may be composed of 5% hydrogen gas and 95% nitrogen gas.

In a preferred embodiment, in the step of supplying a reducing gas containing hydrogen gas and nitrogen gas into the reactor to perform reduction, the temperature is 350°C to 450°C, and the pressure is normal pressure to 40 bar, and reduction can be performed for 6 to 24 hours.

In a preferred embodiment, the reaction gas may be composed of 72% hydrogen gas, 24% carbon dioxide gas, and 4% nitrogen gas.

In a preferred embodiment, in the step of supplying a reaction gas into the reactor to synthesize hydrocarbons through hydrogenation of carbon dioxide, the reaction temperature may be 230°C to 300°C and the reaction pressure may be 10 bar to 40 bar.

In a preferred embodiment, in the step of synthesizing hydrocarbons through hydrogenation of carbon dioxide by supplying reaction gas into the reactor, the space velocity may be 2000 ml/gcat./h to 10000 ml/gcat./h.

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

According to the carbon dioxide reduction catalyst according to the present invention and the method for producing a hydrocarbon compound using the reduction catalyst, a hydrocarbon compound having two or more carbon atoms and having high industrial utility can be produced with high selectivity.

Figure 1 is a graph of _CO2 conversion, _C1 selectivity, _C2-4 selectivity, and C5 ₊ selectivity measured at approximately 1-hour intervals during a reaction period of approximately 60 hours.
Figure 2 is a graph of _CO2 conversion, _C1 selectivity, _C2-4 selectivity, and C5 ₊ selectivity measured at approximately 1-hour intervals during a reaction period of approximately 60 hours.
Figure 3 is a graph of _CO2 conversion, _C1 selectivity, _C2-4 selectivity, and C5 ₊ selectivity measured at approximately 1-hour intervals during a reaction period of approximately 60 hours.
Figure 4 shows the XRD (X-ray Diffraction) analysis results of Examples 1 to 6 and Comparative Examples 1 to 3.
Figure 5 shows the results of a TEM (Transmission Electron Microscopy) analysis experiment of the catalyst after reduction of the catalyst manufactured in Example 2 (top) and the catalyst before reduction of the catalyst manufactured in Comparative Example 3 (bottom).

Hereinafter, preferred embodiments of the present invention will be described in detail.

The present invention may have various modifications and embodiments, and specific embodiments are illustrated in the drawings and specifically described in the detailed description. This is not intended to limit the present invention to specific embodiments, but should be interpreted to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

The term "and/or" may include any combination of multiple related listed items or any one of multiple related listed items.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the invention. Singular expressions may include plural expressions unless the context clearly indicates otherwise.

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 defined in commonly used dictionaries, such as those defined in common dictionaries, may be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and may not be interpreted in an idealized or overly formal sense, unless explicitly defined in this application.

The technical features of the present invention lie in a carbon dioxide reduction catalyst which can act as a catalyst in the hydrogenation reaction of carbon dioxide, thereby increasing the conversion rate in the hydrogenation reaction of carbon dioxide and producing a hydrocarbon compound having two or more carbon atoms with high industrial utility with high selectivity, a method for producing the same, and a method for producing a hydrocarbon compound using the reduction catalyst.

The present invention may include a step of manufacturing a mesoporous silica support; a step of injecting metal into pores of a mesoporous silica template; and a step of removing the silica template to form a composite metal oxide structure having a mesoporous structure.

In the step of preparing a support for mesoporous structure catalyst synthesis, a mixed solution may be prepared by adding Pluronic P123 copolymer (EO20PO70E20), hydrochloric acid (HCl), n-butanol, and silica source to distilled water, and hydrothermal synthesis may be performed. After hydrothermal synthesis, filtering, drying, and calcination may be performed.

After P123 is completely dissolved in distilled water at room temperature, it can be added to a hydrochloric acid solution. After adding n-butanol to the solution, a silica source can be added 1 hour later. The silica source can be tetraethoxysilane (TEOS) or sodium silicate (Na2SiO3). The mixture can be stirred at about 35°C to 38°C for about 24 hours.

The above mixed solution can be transferred to a Teflon container and hydrothermal synthesis can be performed in an oven at about 100°C to 110°C for about 24 to 25 hours. After the hydrothermally synthesized solution has been sufficiently cooled, it can be filtered without washing or by washing with distilled water. After filtering, it can be dried at about 100°C to 110°C for about 30 to 40 minutes. The dried powder can be calcined at about 550°C for about 5 to 10 hours to remove byproducts such as hydrochloric acid.

This is a step of synthesizing a mesoporous structure metal catalyst by filling a metal precursor into the mesoporous silica manufactured in the above step, calcining it, and then removing the silica template.

In order to fill the pores of the mesoporous silica template with a metal precursor, moisture inside the pores can be removed. A metal precursor mixture solution can be injected into the dried silica template. At this time, the metal precursor mixture solution can include a cobalt precursor, a manganese precursor, and an aluminum precursor. The volume of distilled water in the metal mixture solution can be equal to or less than the average pore volume of the silica template. The catalyst can have an average specific surface area of 50 to 200 m ² /g and an average pore size of 2 to 20 nm.

Cobalt nitrate (Co( _NO3 ) ₂ · _6H2O ) or cobalt carbonyl ( _Co2 (CO) ₈ ) can be used as a cobalt precursor, manganese nitrate (Mn( _NO3 ) ₂ · _4H2O ) can be used as a manganese precursor, and aluminum nitrate (Al( _CO3 ) ₃ · _9H2O ) can be used as an aluminum precursor.

The silica mold mixed with the above precursor solution can be sufficiently dried at about 80°C for about 12 hours. By slowly drying at a temperature lower than the boiling point of distilled water, which is a solvent, the distilled water can be evaporated without affecting the morphological structure of the metal material that has penetrated into the pores of the silica mold.

The above dried mesoporous silica mold can be fired at high temperature to change the cobalt oxide precursor, the manganese oxide precursor and the aluminum oxide precursor into oxides of a composite metal including cobalt, manganese and aluminum. The temperature can be increased at a rate of 1°C/min up to 550°C and then fired for 3 hours.

This is a step of forming a composite metal oxide structure having a mesoporous structure by removing the mesoporous silica template from the above metal oxide complex.

In the above metal oxide composite, the mesoporous silica template can be removed using an acidic or basic solution. The silica template can be removed using a NaOH aqueous solution or a hydrofluoric acid (HF) aqueous solution. The mesoporous silica template can be removed using a NaOH aqueous solution having a concentration of about 1 M to 2 M at about room temperature to 60° C. The solution from which the silica template has been removed can be filtered by washing with distilled water. The filtered solution can be dried in an oven at about 110° C. for 30 to 40 minutes. The dried composite can be subjected to the filtering step once more. The composite after the filtering can be dried in an oven at about 110° C. for about 12 hours.

The present invention may also include a method of using the manufactured catalyst from carbon dioxide hydrogenation to a method of producing hydrocarbons.

The above method for producing hydrocarbons from carbon dioxide hydrogenation may include a step of arranging a catalyst inside a reactor, a step of supplying a reducing gas inside the reactor to promote an active site of the catalyst, and a step of supplying a reaction gas to produce hydrocarbons.

In the above reaction, the reactor may be a Fischer-Tropsch fixed bed reactor. After quartz wool is placed inside the reactor, a catalyst may be placed.

The above reducing gas may include hydrogen gas and nitrogen gas, and may include about 5% hydrogen gas and residual nitrogen gas.

The reduction process can be carried out at a temperature of about 350°C to 450°C and a pressure of about 40 bar for about 6 to 24 hours.

The reaction gas for the above carbon dioxide hydrogenation reaction may include hydrogen gas, carbon dioxide gas, and residual nitrogen gas. The ratio of hydrogen and carbon dioxide may be about 3:1, and may include 72% hydrogen gas, 24% carbon dioxide gas, and residual nitrogen gas.

In the reaction step of producing hydrocarbons through carbon dioxide hydrogenation, the reaction temperature may be about 230°C to 300°C and the reaction pressure may be about 10 bar to 40 bar. In a low temperature reaction, it may be about 250°C. The space velocity may be about 2000 ml/gcat./h to 10000 ml/gcat./h, but is not limited thereto.

Hereinafter, a detailed description will be given of a catalyst for the reduction reaction of carbon dioxide according to the present invention through examples. In explaining the principles of preferred examples of the present invention in detail, if it is judged that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

Manufacturing Example 1: Mesoporous silica support

150 ml of distilled water and 18.0 g of Pluronic P123 copolymer were stirred at room temperature until completely dissolved. 32 ml of hydrochloric acid and 500 ml of distilled water were stirred in a three-necked flask at about 35°C. The completely dissolved Pluronic P123 copolymer solution was poured into the stirring hydrochloric acid solution and stirred at about 35°C for about 10 minutes. Then, about 18.0 g of n-butanol was added and stirred at about 35°C. After about 1 hour, about 38.7 g of ethyl silicate was added to the mixed solution and stirred at about 35°C for about 24 hours. It was confirmed that a white precipitate was formed in the opaque solution stirred for about 24 hours. The solution and the precipitate were transferred to a Teflon container. The above Teflon was placed in an autoclave and a hydrothermal synthesis reaction was performed in an oven at about 110°C for about 25 hours. After the hydrothermal synthesis, it was cooled for about 12 hours. The reaction solution was filtered without a washing process until no white foam appeared. The filtered solution was dried in an oven at about 110°C for about 40 minutes. The dried white powder was calcined at 550°C for 6 hours under standard conditions. After the calcination, about 10 g of KIT-6 mesoporous silica in the form of a fine white powder was manufactured.

Example 1: m-CoMn _0.1 Al _0.5

The metal was supported on the KIT-6 support manufactured in the above Manufacturing Example 1 by the IWI method (Incipient Wetness Imregnation). Cobalt, manganese, and aluminum were manufactured in a molar ratio of 1:0.1:0.5, respectively. 10 g of the prepared KIT-6 was dried in an oven at about 110°C for about 1 hour.

(a) Step for preparing a metal precursor mixture solution:

Approximately 18.189 g of cobalt nitrate hexahydrate, approximately 1.794 g of manganese nitrate hexahydrate, and approximately 11.723 g of aluminum nitrate nonahydrate as cobalt precursors were added to 9 ml of distilled water and completely dissolved.

(b) A step of injecting the metal precursor mixture solution into a material having a mesoporous structure:

The solution containing the metal precursor was poured all at once into the dried KIT-6 and mixed thoroughly until the color became uniform without any lumps.

(c) A step of drying the material having the above mesoporous structure and then calcining it to obtain a composite metal oxide:

The above mixed powder was dried in an oven at about 80°C for about 12 hours to evaporate the distilled water. The dried powder was heated to 550°C at a rate of 1°C/min and then calcined at 550°C for 3 hours.

(d) A step of adding the above complex metal oxide to an acidic or basic solution and stirring:

To remove KIT-6 from the calcined composite metal oxide, the calcined composite metal oxide was placed in an aqueous NaOH solution having a concentration of about 2 M and stirred at about 60°C for about 1 hour and 30 minutes.

(e) A step of washing and filtering the acidic or alkaline solution and then drying it:

After stirring, it was washed with distilled water and filtered, and at the same time, impurities floating on the surface of the solution were removed. A small amount of ethanol was added to the filtered solution, and it was dried in an oven at 110°C for about 40 minutes. The dried complex metal oxide was subjected to secondary extraction in the same manner as the KIT-6 removal process. After the secondary extraction, a small amount of ethanol was added to the filtered solution, and it was dried in an oven at about 110°C for about 12 hours.

Finally, a powder-type porous composite metal oxide catalyst was manufactured, and the manufactured catalyst was denoted as m-CoMn _0.1 Al _0.5 . The average surface area was 100.8 m ² /g and the average pore size was 9.9 nm.

The _CO2 hydrogenation reaction was performed as follows using the catalyst manufactured above.

(a) Step of placing a carbon dioxide reduction catalyst inside the reactor:

_CO2 hydrogenation reaction was performed using the above-mentioned manufactured catalyst m-CoMn _0.1 Al _0.5 . After placing about 0.3 g of quartz wool in a fixed bed reactor, about 0.1 g of the catalyst was placed.

(b) A step of reducing by supplying a reducing gas containing hydrogen gas and nitrogen gas into the reactor:

Prior to the reaction, a reducing gas containing about 5% H ₂ gas and residual N ₂ was reduced at about 400°C for about 12 hours at atmospheric pressure.

(c) A step of synthesizing hydrocarbons through hydrogenation of carbon dioxide by supplying reaction gas into the reactor:

After reduction, the reaction was performed by flowing the reaction gas (H ₂ /CO ₂ = 3) of H ₂ (approximately 72%)/CO 2 (approximately 24%)/N ₂ (approximately 4%). The reaction was performed for approximately 60 hours under the reaction conditions of approximately 40 bar of reaction pressure, approximately 250°C of reaction temperature, and approximately 8000 ml/gcat./h of space velocity. The CO ₂ conversion, CO selectivity, hydrocarbon selectivity, and olefin/paraffin selectivity ratio were analyzed using gas chromatography. The average CO ₂ conversion was approximately 51.3%, showing stable activity, and the CO selectivity was approximately 0.4%, minimizing by-product emission. In addition, hydrocarbons with a C _2-4 selectivity of approximately 19.7% and a C ₅₊ selectivity of approximately 5.8% were synthesized.

Example 2: m-CoMn _0.2 Al _0.5

A catalyst was prepared by the IWI method in the same manner as in Example 1, but the composition of manganese was increased. Cobalt, manganese, and aluminum were prepared in a molar ratio of 1:0.2:0.5, respectively. About 17.12 g of cobalt nitrate hexahydrate, about 3.38 g of manganese nitrate hexahydrate, and about 11.03 g of aluminum nitrate nonahydrate were used as metal precursors. Finally, a powder-type porous composite metal oxide was prepared, and the prepared catalyst was expressed as m-CoMn _0.2 Al _0.5 . The average specific surface area was 107.9 m ² /g and the average pore size was 8.6 nm. CO ₂ hydrogenation reaction was performed under the same conditions as in Example 1. The average CO ₂ conversion rate was about 52.0%, showing stable activity, and the CO selectivity was about 0.4%, minimizing by-product emission. Additionally, hydrocarbons with C _2-4 selectivity of approximately 17.5% and C ₅₊ selectivity of approximately 4.3% were synthesized.

Example 3: m-CoMn _0.4 Al _0.5

A catalyst was prepared by the IWI method in the same manner as in Example 1, but the composition of manganese was increased. Cobalt, manganese, and aluminum were prepared in a molar ratio of 1:0.4:0.5, respectively. About 16 g of cobalt nitrate hexahydrate, about 6.312 g of manganese nitrate hexahydrate, and about 10.311 g of aluminum nitrate nonahydrate were used as metal precursors. Finally, a powder-type porous composite metal oxide was prepared, and the prepared catalyst was expressed as m-CoMn _0.4 Al _0.5 . The average specific surface area was 125.2 m ² /g and the average pore size was 9.5 nm. CO2 hydrogenation reaction was performed under the same conditions as in Example 1. The average _CO2 conversion rate was about 57.7%, showing stable activity, and the CO selectivity was about 0.4%, minimizing by-product emission. A hydrocarbon was synthesized with a C _2-4 selectivity of approximately 12.8% and a C ₅₊ selectivity of approximately 1.4%.

Example 4: m-CoMn _0.5 Al _0.5

A catalyst was prepared by the IWI method in the same manner as in Example 1, but the manganese composition was increased. Cobalt, manganese, and aluminum were prepared in a molar ratio of 1:0.5:0.5, respectively. About 16 g of cobalt nitrate hexahydrate, about 7.89 g of manganese nitrate hexahydrate, about 10.31 g of aluminum nitrate nonahydrate, and about 9 ml of distilled water were used as metal precursors. Finally, a powder-type porous structure composite metal oxide was prepared, and the average specific surface area of the prepared catalyst was 180.6 ^m2 /g and the average pore size was 8.9 nm. CO2 hydrogenation reaction was performed under the same conditions as in Example 1. The average _CO2 conversion was about 12.2% and the CO selectivity was about 10.7%. A hydrocarbon was synthesized with a C _2-4 selectivity of approximately 19.0% and a C ₅₊ selectivity of approximately 11.4%.

Example 5

The CO ₂ hydrogenation reaction was performed in the same manner as in Example 2 above, but at a temperature of 230°C. The average CO ₂ conversion rate was approximately 56.1% and the CO selectivity was approximately 0.4%. A hydrocarbon was synthesized with a C _2-4 selectivity of approximately 17.4% and a C5 ₊ selectivity of approximately 4.6%.

Example 6: m-CoMn _0.2

The IWI method was used the same as in Example 2, except that aluminum was excluded. Cobalt and manganese were each prepared in a molar ratio of 1:0.2. About 24.25 g of cobalt nitrate hexahydrate and about 4.78 g of manganese nitrate hexahydrate were used as metal precursors. Finally, a powder-type porous composite metal oxide was prepared, and the prepared catalyst was expressed as m-CoMn _0.2 . The average specific surface area was 100.0 m ² /g and the average pore size was 4.9 nm. CO ₂ hydrogenation reaction was carried out under the same conditions as in Example 2, except that the reduction was performed at about 325°C for about 12 hours, and the reaction space velocity was about 4000 ml/gcat./h. The average CO ₂ conversion rate was about 54.4%, and the CO selectivity was about 0.2%. A hydrocarbon was synthesized with a C _2-4 selectivity of approximately 20.6% and a C ₅₊ selectivity of approximately 12.6%.

Example 7

_CO2 hydrogenation reaction was performed under the same conditions as in Example 6, but reduction was performed at about 350°C for about 12 hours. The average _CO2 conversion rate was about 32.3% and the CO selectivity was about 1.6%. Hydrocarbons with a _C2-4 selectivity of about 21.4% and a C5 ₊ selectivity of about 15.3% were synthesized.

Example 8

_CO2 hydrogenation reaction was performed under the same conditions as in Example 6, but reduction was performed at about 425°C for about 12 hours. The average _CO2 conversion rate was about 40.2% and the CO selectivity was about 0.7%. Hydrocarbons with a _C2-4 selectivity of about 20.9% and a C5 ₊ selectivity of about 12.3% were synthesized.

Example 9

_CO2 hydrogenation reaction was performed under the same conditions as in Example 6, but reduction was performed at about 450°C for about 12 hours. The average _CO2 conversion rate was about 32.1% and the CO selectivity was about 2.0%. Hydrocarbons with a _C2-4 selectivity of about 23.3% and a C5 ₊ selectivity of about 12.9% were synthesized.

Example 10

_CO2 hydrogenation reaction was performed under the same conditions as in Example 6, but reduction was performed at about 350°C for about 6 hours. The average _CO2 conversion rate was about 31.3% and the CO selectivity was about 1.5%. Hydrocarbons with a _C2-4 selectivity of about 19.4% and a C5 ₊ selectivity of about 12.8% were synthesized.

Example 11

_CO2 hydrogenation reaction was performed under the same conditions as in Example 6, but reduction was performed at about 450°C for about 6 hours. The average _CO2 conversion rate was about 39.5% and the CO selectivity was about 1.7%. Hydrocarbons with a _C2-4 selectivity of about 20.5% and a C5 ₊ selectivity of about 11.9% were synthesized.

Example 12: m-CoMn _0.2 Zn _0.5

A catalyst was prepared by the IWI method in the same manner as in Example 2, except that zinc was used instead of aluminum. Cobalt, manganese, and zinc were prepared in a molar ratio of 1:0.2:0.5, respectively. About 3 g of KIT-6 was used, and about 5 g of cobalt nitrate hexahydrate, about 0.986 g of manganese nitrate hexahydrate, about 2.555 g of zinc nitrate hexahydrate, and about 3 ml of distilled water were used as metal precursors. Finally, a powder-type porous structure composite metal oxide was prepared, and the average specific surface area of the prepared catalyst was 115.2 ^m2 /g and the average pore size was 5.3 nm. _CO2 hydrogenation reaction was performed under the same conditions as in Example 1. The average _CO2 conversion was about 29.4% and the CO selectivity was about 10.7%. A hydrocarbon was synthesized with a C _2-4 selectivity of approximately 19.0% and a C ₅₊ selectivity of approximately 11.4%.

Comparative Example 1: m-CoAl _0.5

The IWI method was used the same as in Example 1, except that manganese was excluded. Cobalt and aluminum were prepared in a molar ratio of 1:0.5, respectively. About 16 g of cobalt nitrate hexahydrate and about 10.31 g of aluminum nitrate nonahydrate were used as metal precursors. Finally, a powder-type porous structure composite metal oxide was prepared, and the average specific surface area of the prepared catalyst was 113.7 ^m2 /g and the average pore size was 4.3 nm. _CO2 hydrogenation reaction was performed under the same conditions as in Example 1. The average _CO2 conversion rate showed stable activity at about 57.5%, but the _C1 selectivity was 92.4%, so most of the reaction proceeded as methanation.

Comparative Example 2: m-CoMn _0.05 Al _0.5

A catalyst was prepared by the IWI method in the same manner as in Example 1, except that the manganese composition was reduced. Cobalt, manganese, and aluminum were prepared in a molar ratio of 1:0.05:0.5, respectively. About 16 g of cobalt nitrate hexahydrate, about 0.789 g of manganese nitrate hexahydrate, about 10.311 g of aluminum nitrate nonahydrate, and about 10 ml of distilled water were used as metal precursors. Finally, a powder-type porous structure composite metal oxide was prepared, and the average specific surface area of the prepared catalyst was 111.5 ^m2 /g and the average pore size was 5.9 nm. _CO2 hydrogenation reaction was performed under the same conditions as in Example 1. It showed a high _CO2 conversion of 50.7% and a low CO selectivity of 0.6%, but a _C2-4 selectivity of 5.6% and a low C5 ₊ selectivity of 0.34%.

Comparative Example 3: m-CoMnAl _0.5

A catalyst was prepared by the IWI method in the same manner as in Example 1, but the composition of manganese was increased. Cobalt, manganese, and aluminum were prepared in a molar ratio of 1:1:0.5, respectively. About 14 g of cobalt nitrate hexahydrate, about 13.80 g of manganese nitrate hexahydrate, and about 9.02 g of aluminum nitrate nonahydrate were used as metal precursors. Finally, a powder-type porous structure composite metal oxide was prepared, and the average specific surface area of the prepared catalyst was 104.2 m ² /g and the average pore size was 5.4 nm. CO ₂ hydrogenation reaction was performed under the same conditions as in Example 1. It exhibited a low CO ₂ conversion of 10.1%, a high CO selectivity of 13.3%, and a high C ₁ selectivity of 82.6%.

Comparative Example 4

The CO ₂ hydrogenation reaction was performed in the same manner as in Example 2, but at a temperature of 270°C. The average CO ₂ conversion rate was approximately 58.0% and the CO selectivity was approximately 0.3%. The C _2-4 selectivity was approximately 8.1% and the C ₅₊ selectivity was approximately 0.5%, showing low hydrocarbon selectivity.

Comparative Example 5

_CO2 hydrogenation reaction was carried out under the same conditions as in Example 6, but reduction was performed at about 400°C for about 12 hours. The average _CO2 conversion rate was about 56.0% and the CO selectivity was about 0.1%. It showed a _C2-4 selectivity of about 11.3% and a C5 ₊ selectivity of about 3.7%.

The reaction results according to the type and composition of the catalyst metal are shown in Table 1.

<Table 1>

As shown in Table 1 above, it was confirmed in the experimental results of Examples 1 to 4, which are catalysts adding manganese, that the hydrocarbon selectivity of C _2-4 and C ₅₊ increased compared to Comparative Example 1, which used a catalyst without adding manganese. In particular, Examples 1 to 3 exhibited high CO ₂ conversion and Example 4 exhibited high hydrocarbon selectivity. It was confirmed that Comparative Example 2, which had a very small amount of manganese, and Comparative Example 3, which had the largest amount of manganese, had decreased catalytic performance. Reflecting the experimental data of Comparative Examples 2 and 3, the range of x in Chemical Formula 1 of Claim 1 was limited to a range greater than 0.05 and less than 1. In addition, in Example 12, where zinc was replaced with aluminum in Example 2, the hydrocarbon selectivity increased.

The results of _CO2 hydrogenation performed by changing the reaction temperature using the catalyst synthesized in Example 2 are shown in Table 2.

<Table 2>

Examples 2 and 3 showed similar results. At a high temperature of 270°C, the highest _CO2 conversion rate was observed, but most of the reaction proceeded as methanation.

_CO2 hydrogenation was performed by changing the reduction temperature and time conditions using the catalyst synthesized in Example 6, and the comparison of results is shown in Table 3.

<Table 3>

Examples 6 to 11 showed similar hydrocarbon selectivity, and Example 7, which was reduced at 350°C for 12 hours, showed the highest C ₅₊ selectivity. On the other hand, Comparative Example 5, which was reduced at 400°C for 12 hours, proceeded mostly through methanation reaction.

The overall results are summarized in Table 4. Example 7 showed the highest C ₅₊ selectivity, and Example 9 showed the highest C _2-4 selectivity. Examples 7 and 9 showed the lowest selectivity.

<Table 4>

Although the present invention has been described in detail through specific examples, this is only for the purpose of specifically explaining the present invention, and the present invention is not limited thereto, and it is obvious that the present invention can be modified or improved by a person having ordinary knowledge in the relevant field within the technical spirit of the present invention.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific protection scope of the present invention will be made clear by the appended claims.

Claims (18)

A carbon dioxide reduction catalyst represented by the following chemical formula 1.
[Chemical Formula 1]
CoMn _x Al _y Zn _z (

,

,

,

)
In paragraph 1,
The above catalyst is a carbon dioxide reduction catalyst characterized in that an active metal is supported on a material having a mesoporous structure.
In paragraph 1,
The above catalyst is a carbon dioxide reduction catalyst characterized by being CoMn _x Al _0.5 (0.1≤x≤0.5) or CoMn _0.2 Zn _0.5 .
In the second paragraph,
The above catalyst is a carbon dioxide reduction catalyst characterized by having an average specific surface area of 50 to 200 m ² /g.
In the second paragraph,
The above catalyst is a carbon dioxide reduction catalyst characterized by an average pore size of 2 to 20 nm.
In a method for producing a carbon dioxide reduction catalyst represented by chemical formula 1 according to Article 1,
A step of preparing a metal precursor mixture solution by dispersing a metal precursor further including a manganese precursor, an aluminum precursor or a zinc precursor in addition to a cobalt precursor in a solvent;
A step of injecting the metal precursor mixture solution into a material having a mesoporous structure;
A step of drying and then calcining the material having the above mesoporous structure to obtain a composite metal oxide;
A step of adding the above complex metal oxide to an acidic or basic solution and stirring; and
A method for producing a carbon dioxide reduction catalyst, characterized in that it acts as a catalyst in the hydrogenation reaction of carbon dioxide, comprising the steps of washing and filtering the acidic or basic solution and then drying it.
In paragraph 6,
The above-mentioned calcination treatment is a method for manufacturing a carbon dioxide reduction catalyst, which comprises calcination treatment by raising the temperature to 450°C to 650°C.
In paragraph 6,
A method for producing a carbon dioxide reduction catalyst, characterized in that the acidic solution is an HF aqueous solution.
In paragraph 6,
A method for producing a carbon dioxide reduction catalyst, characterized in that the above basic solution is a NaOH aqueous solution.
In paragraph 6,
A method for producing a carbon dioxide reduction catalyst, characterized in that the above composite metal oxide is stirred in an acidic or basic solution at room temperature to 60°C.
A step of arranging a carbon dioxide reduction catalyst of any one of claims 1 to 5 inside a reactor;
A step of reducing by supplying a reducing gas containing hydrogen gas and nitrogen gas into the reactor; and
A step of synthesizing hydrocarbons through hydrogenation of carbon dioxide by supplying reaction gas into the reactor;
A method for producing a hydrocarbon compound comprising:
In Article 11,
A method for producing a hydrocarbon compound, characterized in that the above reactor is a Fischer-Tropsch fixed bed reactor and quartz wool is placed inside the reactor.
In Article 11,
A method for producing a hydrocarbon compound, characterized in that the reducing gas is composed of 5% hydrogen gas and 95% nitrogen gas.
In Article 11,
A method for producing a hydrocarbon compound, characterized in that, in the reducing step, the internal temperature of the reactor is 350°C to 450°C and the internal pressure is normal pressure to 40 bar for 6 to 24 hours.
In Article 11,
A method for producing a hydrocarbon compound, characterized in that the above reaction gas is composed of 72% hydrogen gas, 24% carbon dioxide gas, and 4% nitrogen gas.
In Article 11,
A method for producing a hydrocarbon compound, characterized in that the reaction temperature in the step of synthesizing the hydrocarbon is 230°C to less than 270°C and the reaction pressure is 10 bar to 40 bar.
In Article 11,
A method for producing a hydrocarbon compound, characterized in that the space velocity of the step of synthesizing the hydrocarbon is 2000 to 10000 ml/gcat./h.
In Article 11,
A method for producing a hydrocarbon compound, characterized in that the hydrocarbon compound has 1 to 20 carbon atoms.