KR20210075543A - Methane oxidation catalyst, preparation method thereof and partial oxidation of methane using the same - Google Patents

Abstract

The present invention relates to a methane oxidation catalyst, a manufacturing method thereof, and a partial oxidation method of methane using the same, and more particularly, to a methane oxidation catalyst in which a structure formed by coordinating copper ions in imidazole present inside a zeolitic imidazolate structure (ZIF) is manufactured and by using the same, the methane is not peroxidized to formic acid, exhibiting excellent efficiency for selective partial oxidation to methanol, and being easy to be collected and reused.

Description

Methane oxidation catalyst, preparation method thereof, and partial oxidation method of methane using the same

The present invention relates to a methane oxidation catalyst, a method for producing the same, and a method for partial oxidation of methane using the same, and more particularly, to a copper ion in imidazole present in a zeolitic imidazolate framework (ZIF, Zeolitic Imidazolate Framework). A technology for preparing this coordinated structure and using it as a methane oxidation catalyst that not only shows excellent efficiency for selective partial oxidation to methanol without peroxidation of methane to formic acid, but also is easy to collect and reuse will be.

In general, in converting natural gas into useful products, it is essential to develop a catalyst for oxidation of hydrocarbons with high selectivity and yield. However, it is difficult to develop a catalyst having both high yield and selectivity in oxidizing strong C-H bonds. As a solution, development of an oxidation catalyst that guarantees high selectivity to methanol under mild conditions is required.

In particular, the oxidation reaction of methane is an important reaction in industry. Conventionally, after decomposing methane into syngas at a high temperature, the reaction of converting it back to methanol proceeds in two steps and consumes a lot of energy, so research is being conducted to directly partially oxidize methane at a low temperature.

However, since high energy is required to activate the strong C-H bond of methane, conversion is difficult, and even if possible, the C-H bond of methanol, the product, is weaker, so that it is peroxidized with formic acid or the like.

Therefore, in order to solve this problem, development of an oxidation catalyst capable of stably generating methanol without peroxidation under conditions in which methane is oxidized is required.

Patent Literature 1. Korean Patent Publication No. 10-0343550 Patent Document 2. Korean Patent Publication No. 10-1800676

The present invention has been devised in consideration of the above problems, and an object of the present invention is to prepare a structure formed by coordinating copper ions with imidazole present inside a zeolitic imidazolate structure, and using this to prepare a methane structure It is intended to be applied as a catalyst for methane oxidation that is not peroxidized to formic acid and exhibits excellent efficiency for selective partial oxidation to methanol, and is easy to collect and reuse.

One aspect of the present invention for achieving the object as described above is a metal-organic structure represented by the following formula (1); and copper ions coordinated to imidazole present in the metal-organic structure. It relates to a methane oxidation catalyst comprising a.

[Formula 1]

n is a natural number from 1 to 100,000.

Another aspect of the present invention relates to a method for partial oxidation of methane, comprising the step of selectively synthesizing methanol by reacting methane, an oxidizing agent, and the methane oxidation catalyst according to the present invention.

Another aspect of the present invention is (a) obtaining a first mixed solution in which a zinc precursor and a first organic solvent are mixed, and a second mixed solution in which benzimidazole and a second organic solvent are mixed, (b) the above Mixing the first mixed solution and the second mixed solution to obtain a metal-organic structure represented by Chemical Formula 1, and (c) mixing the obtained metal-organic structure and the copper ion precursor under distilled water. It relates to a method for producing a methane oxidation catalyst.

According to the present invention, a structure formed by coordinating copper ions with imidazole present inside a zeolitic imidazolate structure is prepared, and by using this, methane is not peroxidized to formic acid and selective partial oxidation to methanol In addition to exhibiting excellent efficiency, it can be applied as a methane oxidation catalyst that is easy to collect and reuse.

1 is a schematic diagram showing the structure of a methane oxidation catalyst according to the present invention.
2 is a scanning electron microscope (SEM) image of the methane oxidation catalyst prepared in Example 1.
3 is a graph showing the results of X-ray diffraction analysis (XRD) analysis of the zinc-imidazole structure (ZIF) of Comparative Example 1 before (CuZIF_before) and after (CuZIF_after) the catalytic reaction of the methane oxidation catalyst prepared in Example 1; .
4 is a graph showing catalytic activity results according to the amount of copper ion precursor added to the methane oxidation catalyst according to Examples 1 to 5 and Comparative Example 1 [x-axis is Cu ion precursor content (μmol) with respect to 20 mg of ZIF-7].
5 is a graph showing results of catalytic activity according to the amount of oxidizing agent added to the methane oxidation catalyst according to Example 1. FIG.
6 is a graph showing catalytic activity results according to the oxidation reaction temperature of the methane oxidation catalyst according to Example 1 [x-axis is the molar concentration of hydrogen peroxide (M)].
7 is a graph showing results of catalytic activity according to the oxidation reaction time of the methane oxidation catalyst according to Example 1. FIG.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

One aspect of the present invention is a metal-organic structure represented by the following Chemical Formula 1; and copper ions coordinated to imidazole present in the metal-organic structure. It relates to a methane oxidation catalyst comprising (see FIG. 1).

[Formula 1]

n is a natural number from 1 to 100,000.

The repeating unit n of Formula 1 may be a natural number of 1 or more, and specifically may be a natural number of 1 to 100,000.

The oxidation of methane is an important reaction in industry. Conventionally, after decomposing methane into syngas at a high temperature, the reaction of converting it back to methanol proceeds in two steps and consumes a lot of energy, so research is being conducted to directly partially oxidize methane at a low temperature. However, since high energy is required to activate the strong C-H bond of methane, conversion is difficult, and even if possible, the C-H bond of methanol, the product, is weaker and thus peroxidized with formic acid or the like. As a solution, development of an oxidation catalyst capable of stably generating methanol without peroxidation under conditions in which methane is oxidized is required. Accordingly, in the present invention, by providing a methane oxidation catalyst in which an imidazole group present in a defective portion of ZIF, which is a crystal in which zinc and imidazole is repeated, is used as an electron donor and coordinated to a copper ion, methane is converted to methanol without peroxidation In addition to exhibiting excellent selectivity for the partial oxidation of , it has the advantage of being easy to collect and reuse.

The metal-organic structure represented by Chemical Formula 1 is a zeolitic imidazolate structure (ZIF), which means a crystal in which zinc and imidazole are repeated, and has many pores similar to zeolite. It is characterized in that the imidazole group may be exposed to the interface with water as it may not be completely crystallized and may have defects, and metal ions may bind. In addition, it is characterized in that it is hydrophobic by the 2, 4, and 5 substituents of imidazole.

The ZIF crystal of Formula 1 includes benzimidazole, which is an imidazole derivative, and zinc. Zinc and benzimidazole are linked through a zinc-nitrogen coordination bond. In this case, the imidazole functional group may act as an electron donor and act as a ligand for zinc and copper ions.

Imidazole is known to bind well to metals in living organisms. By binding imidazole exposed to defects with copper ions, sites that can act as partial oxidation catalysts of methane are formed in the pores, thereby improving the reaction rate. In addition, since the oxidation catalyst synthesized in this way is a crystal having a micrometer size, it has the potential to be used as a collectable and reusable catalyst.

According to one embodiment, the metal-organic structure represented by Formula 1 has a molar ratio (Zn:Cu) of zinc and copper ions of 1: 0.03 to 0.17, preferably 1: 0.03 to 0.15, more preferably 1: 0.03 to 0.09, most preferably 1: 0.03 to 0.07.

According to another embodiment, the content of copper ions relative to the metal-organic structure is 0.01 to 1 μmol/mg, specifically 0.05 to 0.8 μmol/mg, more specifically 0.1 to 0.5 μmol/mg, more specifically 0.1 to 0.2 μmol/mg.

In particular, in the range of 0.1 to 0.2 μmol/mg, methane is not peroxidized to formic acid at all, unlike the case outside the range where some peroxidation occurs, and the amount of methane peroxidized to formic acid and carbon dioxide compared to the case outside the range It was confirmed that this significantly low catalytic activity.

According to another embodiment, the metal-organic structure may have a diameter of 10 to 200 nm, specifically 20 to 100 nm, more specifically 30 to 80 nm, more specifically 50 to 60 nm, and , The methane oxidation catalyst may be a square plate crystal having a diameter of 0.1 to 50 μm, specifically 0.2 to 30 μm, more specifically 0.5 to 10 μm, and more specifically 1 to 3 μm.

Another aspect of the present invention relates to a method for partial oxidation of methane, comprising the step of selectively synthesizing methanol by reacting methane, an oxidizing agent, and the methane oxidation catalyst according to the present invention.

In general, methane has a strong CH bond and requires a catalyst with high yield and selectivity to oxidize it. According to the present invention, similar to the active site of particulate methane monooxygenase, which is widely known as methane oxidase, The oxidation catalyst can be used to oxidize methane with excellent efficiency.

As an example, the oxidation catalyst has a structure in which a copper ion is coordinated to a ZIF crystal containing imidazole to form a structure similar to the activation site of a natural oxidase, so that it can serve as an effective catalyst for the oxidation reaction of methane. .

Specifically, the methane oxidation catalyst and the oxidizing agent according to the present invention are introduced into the high-pressure reactor, and the methane gas is fed into the high-pressure reactor at a pressure of 10 to 50 bar, more specifically 20 to 40 bar, and more specifically 25 to 35 bar. After filling, the reaction may be carried out for 10 to 240 minutes, more specifically 20 to 120 minutes, and more specifically 25 to 35 minutes.

In particular, it was confirmed that the yield of methanol increases as the oxidation reaction time increases, but the yield of carbon dioxide to be peroxidized remarkably increases, so it is preferable to carry out the oxidation reaction for 25 to 35 minutes.

In addition, the reaction temperature may be 10 to 100 ℃, more specifically 30 to 90 ℃, more specifically 50 to 70 ℃, in particular, at the reaction temperature of 50 to 70 ℃ high methanol yield while showing low The yields of formic acid and carbon dioxide were shown, and it was confirmed that the best catalytic activity was exhibited.

According to one embodiment, the oxidizing agent is 0.01 to 5 M, specifically 0.05 to 4.545 M, more specifically 0.25 to 2 M, more specifically 0.5 M to 1 M based on 20 mg of the methane oxidation catalyst. A cyclic hydrocarbon can be oxidized by mixing and reacting in a ratio.

In particular, when 0.5 M to 1 M of the oxidizing agent was added, the highest methanol yield and low carbon dioxide yield were observed, confirming the most excellent catalytic activity.

The oxidizing agent may be hydrogen peroxide, TERT-butyl hydroperoxide, oxygen or air, but is not limited thereto. Specifically, hydrogen peroxide can be used.

Another aspect of the present invention is (a) obtaining a first mixed solution in which a zinc precursor and a first organic solvent are mixed, and a second mixed solution in which benzimidazole and a second organic solvent are mixed, (b) the above Mixing the first mixed solution and the second mixed solution to obtain a metal-organic structure represented by the following Chemical Formula 1, and (c) mixing the obtained metal-organic structure and the copper ion precursor under distilled water. It relates to a method for producing a methane oxidation catalyst.

[Formula 1]

n is a natural number from 1 to 100,000.

According to one embodiment, the first organic solvent and the second organic solvent are the same as or different from each other and each independently diethylformamide, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrroly It may be one or a mixture of two or more selected from money, isopropanol, methanol, and ethanol, but is not limited thereto. Specifically, the first organic solvent may be dimethylformamide, and the second organic solvent may be methanol.

According to another embodiment, the zinc precursor is nitrate, chloride, bromide, iodide, nitrite, sulfate, acetate, sulfite ( sulfite), acetylacetonate salt (acetylacetoante), hydroxide (hydroxide), and may be in the form of one or more selected from hydrates thereof, but is not limited thereto. Specifically, zinc nitrate, more specifically zinc nitrate hydrate (Zn(NO ₃ ) ₂ oxH ₂ O), and more specifically zinc nitrate hexahydrate (Zn(NO ₃ ) ₂ o 6H ₂ O) may be used. .

According to another embodiment, the copper ion precursor may be in the form of one or more selected from nitrate, chloride, bromide, iodide, nitrite, sulfate, acetate, sulfite, acetylacetonate, hydroxide, and hydrates thereof. and is not limited thereto. Specifically, copper nitrate, more specifically copper nitrate hydrate (Cu(NO ₃ ) ₂ oxH ₂ O), and more specifically copper nitrate hexahydrate (Cu(NO ₃ ) ₂ o 6H ₂ O) may be used. .

According to another embodiment, the molar ratio of the zinc precursor and benzimidazole in step (a) may be 1:1 to 10, specifically 1:1.5 to 5, and more specifically 1:2 to 3 .

According to another embodiment, step (b) may be performed at room temperature for 1 to 100 minutes, specifically 5 to 60 minutes, more specifically 10 to 50 minutes, and more specifically 20 to 40 minutes. .

When the reaction of step (b) is completed, a large amount of ZIF crystals can be obtained through centrifugation, and a step of sufficiently drying the obtained ZIF crystals can be further performed.

According to another embodiment, step (c) may be performed at room temperature for 1 to 100 minutes, specifically 5 to 60 minutes, more specifically 10 to 50 minutes, and more specifically 20 to 40 minutes. .

Specifically, in step (c), 100 mg of the metal-organic structure crystals dried sufficiently in step (b) are dispersed in 10 ml of water, and then reacted with an aqueous solution containing the copper ion precursor at room temperature. A methane oxidation catalyst can be prepared according to

According to another embodiment, in the step (c), the zinc and copper ion precursors of the metal-organic structure represented by Chemical Formula 1 are Zn: Cu = 1: 0.03 to 0.17, specifically 1: 0.03 to 0.15, more Specifically, it may be mixed in a molar ratio of 1: 0.03 to 0.09, more specifically 1: 0.03 to 0.07.

According to another embodiment, in step (c), the metal-organic structure and the copper ion precursor represented by Chemical Formula 1 are 0.01 to 1 μmol/mg, specifically 0.05 to 0.8 μmol/mg, more specifically 0.1 to 0.5 μmol/mg, more specifically, it may be mixed at a ratio of 0.1 to 0.2 μmol/mg. In the range of 0.1 to 0.2 μmol/mg, methane is not peroxidized to formic acid at all, and the amount of peroxidation of methane to carbon dioxide is significantly lower than in the case outside the above range, showing the best catalytic activity.

In particular, although not explicitly described in the following Examples or Comparative Examples, in the methane oxidation catalyst according to the present invention, the molar ratio and content ratio of copper ions to the metal-organic structure of Formula 1 and the diameter of the metal-organic structure The durability was confirmed by performing SEM imaging and 300 times of methane oxidation reaction for the methane oxidation catalysts that were changed.

As a result, unlike in other numerical ranges, (i) the molar ratio of zinc and copper ions of the metal-organic structure represented by Formula 1 is 1: 0.03 to 0.17, and (ii) the content of copper ions compared to the metal-organic structure is 0.1 to 0.2 μmol/mg, (iii) the diameter of the metal-organic structure is 50 to 60 nm, and (iv) the methane oxidation catalyst is a square plate crystal having a diameter of 1 to 3 μm When all of the conditions are satisfied , SEM imaging results showed that the loss of copper ions bound to the metal-organic structure of Formula 1 was not observed at all in the entire area of the catalyst, and the initial methane oxidation reaction efficiency (selectivity of partial oxidation of methane) was similar to that of 300 times methane oxidation reaction efficiency. It was confirmed that the durability was very good by showing the same value within the error range of the measuring device.

However, when any one of the above conditions is not satisfied, it is confirmed that the loss of copper ions contained in the methane oxidation catalyst occurs partially, and the efficiency of the 300-time methane oxidation reaction is lowered to an observable level compared to the initial oxidation reaction efficiency. did.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present invention, terms such as 'comprising' or 'having' are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Example

Hereinafter, manufacturing examples and examples according to the present invention will be described in detail with accompanying drawings. The following manufacturing examples and examples are merely examples for explaining the present invention, and thereby the scope of the present invention is reduced and cannot be interpreted.

Throughout this specification, "%" used to indicate the concentration of a specific substance means weight % for solids and % by volume for liquids, unless otherwise specified.

Examples 1 to 5: Preparation of methane oxidation catalyst

Zinc nitrate hydrate (Zn(NO ₃ ) ₂ ㅇ6H ₂ O) powder was added to dimethylformamide, benzimidazole powder was added to methanol, the two mixed solutions were mixed and reacted at room temperature for 30 minutes (zinc A molar ratio of benzimidazole to 1:2), and a large amount of zinc-imidazole structure (ZIF) crystals were obtained through centrifugation (ZIF of Formula 1). The ZIF crystal prepared in this way contains defects, so that imidazole groups are exposed at the interface.

Next, 100 mg of sufficiently dried ZIF crystals were dispersed in 10 mL of water, and _{an aqueous solution containing copper nitrate hydrate (Cu(NO 3} ) ₂ ㅇ6H ₂ O) was mixed and reacted at room temperature for 30 minutes to catalyze methane oxidation. was prepared.

At this time, the mixing ratio of the ZIF crystal and the copper nitrate hydrate was 1 mg: 0.1 μmol (Cu/Zn = 0.033) (Example 1), 1 mg: 0.2 μmol (Cu/Zn = 0.070) (Example 2), 1 mg: 0.3 μmol (Cu/Zn = 0.094) (Example 3), 1 mg: 0.4 μmol (Cu/Zn = 0.144) (Example 4), and 1 mg: 0.5 μmol (Cu/Zn = 0.167) (execution) In Example 5), a methane oxidation catalyst was prepared.

Comparative Example 1

The zinc-imidazole structure (ZIF) obtained in Example 1 was used as Comparative Example 2.

Experimental Example 1

In order to examine the form and binding relationship of the oxidation catalyst according to the present invention, scanning electron microscope (SEM) imaging was performed on the methane oxidation catalyst prepared in Example 1, and analysis was performed by X-ray diffraction analysis (XRD). was carried out, and the results are shown in FIGS. 2 and 3 .

2 is an image of the oxidation catalyst prepared in Example 1 taken with a scanning electron microscope. Specifically, referring to FIG. 2 , it can be seen that FIG. 2a is a ZIF crystal having a crystal size of 50 to 60 nm. FIG. 2b is an image after the copper ions are combined, and it can be confirmed that the copper ions form a thin plate-shaped crystal with a size of 1 to 3 μm while the copper ions are combined.

3 is an X-ray diffraction analysis graph of the zinc-imidazole structure (ZIF) of Comparative Example 2 before (CuZIF_before) and after (CuZIF_after) and after the catalytic reaction of the methane oxidation catalyst prepared in Example 1; It can be confirmed that a new crystal structure is formed by looking at the peaks shifting to the right when doping, and the methane oxidation catalyst of Example 1 has no peak shift before and after the catalytic reaction, and the crystal structure is maintained even after the catalytic reaction. can confirm.

Experimental Example 2

In order to examine the catalytic activity of the methane oxidation catalyst according to the present invention, the catalytic activity in the oxidation reaction of methane was evaluated for the oxidation catalysts prepared in Examples 1 to 5 and Comparative Example 1. The specific evaluation method is as follows, and the results are shown in Tables 1 to 3 and FIGS. 4 to 7 below.

(A) Catalytic activity by controlling the amount of copper ions

_{5 ml of distilled water (H 2} O) containing 20 mg of the oxidation catalyst prepared in Examples 1 to 5 and Comparative Example 2 and 5 ml (1 M) of hydrogen peroxide diluted to an appropriate concentration were placed in a high-pressure reactor, and methane was added to 30 bar After filling with , it was reacted at a reaction temperature of 50 °C for 30 minutes. After the reaction, the gas was collected and analyzed by gas chromatography, the liquid was centrifuged to remove the catalyst, and the supernatant was analyzed by hydrogen-nuclear magnetic resonance spectroscopy, and the results are shown in FIG. 4 and Table 1 below [ 4, the x-axis is Cu ion precursor content (μmol) for ZIF-7 20 mg].

Referring to FIG. 4 and Table 1 below, in Comparative Example 1 using the ZIF crystal to which copper ions are not bound as an oxidation catalyst, it can be confirmed that the yield of methanol is significantly low because methane is peroxidized with formic acid, and copper ions are bound In all of Examples 1 to 5, which are ZIF, methane is not peroxidized to formic acid at all, and it can be confirmed that the partial oxidation selectivity to methanol is remarkably excellent. In particular, in the case of Example 1, the amount of peroxidation of methane to carbon dioxide is significantly lower than in the other examples, and it can be confirmed that the best catalytic activity is shown.

Copper Ion: ZIF Ratio
(μmol : mg) CH ₃ OH
Yield (μmol/g) CH ₃ OOH
Yield (μmol/g) HCOOH
Yield (μmol/g) CO ₂
yield
(μmol/g) Example 1 0.1:1 26.6 130.9 0 722.3 Example 2 0.2:1 45.6 217.5 0 1278.2 Example 3 0.3 : 1 55.6 321.5 0 1719.9 Example 4 0.4:1 83.0 398.0 0 2206.8 Example 5 0.5:1 77.6 491.0 0 2936.8 Comparative Example 1 0 : 1 1.5 6.4 144.6 116.2

(B) Catalytic activity according to temperature and amount of hydrogen peroxide

In order to confirm the optimum conditions for the oxidation reaction, the catalytic activity experiment was conducted while changing the reaction temperature and the amount of hydrogen peroxide added, and the results are shown in Table 2, Figures 5 and 6 below. At this time, the ratio of copper ions to ZIF is 0.1 μmol: 1 mg, all the same, and the methane pressure is 30 bar [in FIG. 6, the x-axis is the molar concentration of hydrogen peroxide (M)].

Referring to FIGS. 5 and 6 and Table 2 below, at a reaction temperature of 50° C., high methanol yields and low formic acid and carbon dioxide yields are exhibited, indicating the most excellent catalytic activity. In addition, with respect to the amount of hydrogen peroxide added, when 0.5 M hydrogen peroxide is added, the highest methanol yield and low formic acid and carbon dioxide yields are exhibited, indicating the most excellent catalytic activity.

number Temperature
(℃) Amount of hydrogen peroxide added
(mmol) CH ₃ OH
yield
(μmol/g) CH ₃ OOH
yield
(μmol/g) HCOOH
yield
(μmol/g) CO ₂
yield
(μmol/g) One 30 5 8.9 6.4 0 n.d. 2 50 5 26.6 130.9 0 722.3 3 70 5 49.7 419.2 0 16795.4 4 90 5 25.0 2.1 0 23434.4 5 50 0.5 4.4 12.5 0 58.2 6 50 2.5 6.4 23.9 0 174.3 7 50 20 28.9 118.7 0 2217.7 8 50 45.45 23.9 151.7 0 5338.8

(C) Catalytic activity over time

The methane oxidation reaction catalytic activity experiment of the oxidation catalyst according to time was conducted, and the results are shown in Table 3 and FIG. 7 . At this time, the ratio of copper ion and ZIF is the same as 0.1 μmol: 1 mg, the amount of hydrogen peroxide added is 5 mmol, and the pressure of methane is 30 bar.

Referring to FIG. 7 and Table 3 below, as the oxidation reaction time increases, the yield of methanol increases, but the yields of formic acid and carbon dioxide to be peroxidized remarkably increase, so it is judged that it is preferable to carry out the oxidation reaction for 30 minutes. do.

number time (h) CH ₃ OH
yield
(μmol/g) CH ₃ OOH
yield
(μmol/g) HCOOH
yield
(μmol/g) CO ₂
yield
(μmol/g) One 0.5 26.6 130.9 0 722.3 2 One 35.4 179.2 0 1063.0 3 2 55.5 232.7 0 2055.5 4 4 96.5 420.0 0 3498.3

Therefore, according to the present invention, a structure formed by coordinating copper ions with imidazole present inside a zeolitic imidazolate structure is prepared, and using this, methane is not peroxidized to formic acid, and selective partial oxidation to methanol is performed. It can be applied as a methane oxidation catalyst that is easy to collect and reuse, as well as showing excellent efficiency.

Claims (15)

A metal-organic structure represented by the following Chemical Formula 1; and
Methane oxidation catalyst comprising a; copper ions coordinated to imidazole present in the metal-organic structure.
[Formula 1]

According to claim 1,
The metal-organic structure represented by Formula 1 has a molar ratio of zinc and copper ions of 1: 0.03 to 0.17. According to claim 1,
Methane oxidation catalyst, characterized in that the content of copper ions compared to the metal-organic structure is 0.01 to 1 μmol/mg. According to claim 1,
The metal-organic structure has a diameter of 10 to 200 nm,
The methane oxidation catalyst is a methane oxidation catalyst, characterized in that the square plate crystals having a diameter of 0.1 to 50 μm. According to claim 1,
The molar ratio of zinc and copper ions of the metal-organic structure represented by Formula 1 is 1: 0.03 to 0.17,
The content of copper ions compared to the metal-organic structure is 0.1 to 0.2 μmol/mg,
The metal-organic structure has a diameter of 50 to 60 nm,
The methane oxidation catalyst is a methane oxidation catalyst, characterized in that the square plate crystals having a diameter of 1 to 3 μm. A method for partial oxidation of methane comprising the step of selectively synthesizing methanol by reacting methane, an oxidizing agent, and the methane oxidation catalyst according to any one of claims 1 to 5. 7. The method of claim 6,
The method for partial oxidation of methane, characterized in that the oxidizing agent is reacted by mixing in a ratio of 0.01 to 5 M based on 20 mg of the methane oxidation catalyst. (a) obtaining a first mixed solution in which a zinc precursor and a first organic solvent are mixed, and a second mixed solution in which benzimidazole and a second organic solvent are mixed;
(b) mixing the first mixed solution and the second mixed solution to obtain a metal-organic structure represented by the following Chemical Formula 1, and
(c) a method for producing a methane oxidation catalyst comprising the step of mixing the obtained metal-organic structure and the copper ion precursor under distilled water.
[Formula 1]

9. The method of claim 8,
The first organic solvent and the second organic solvent are the same as or different from each other and are each independently diethylformamide, dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, isopropanol, methanol and A method for producing a methane oxidation catalyst, characterized in that it is one or a mixture of two or more selected from ethanol. 9. The method of claim 8,
The zinc precursor is nitrate, chloride, bromide, iodide, nitrite, sulfate, acetate, sulfite, acetylacetonate A method for producing a methane oxidation catalyst, characterized in that at least one selected from salt (acetylacetoante), hydroxide (hydroxide) and hydrates thereof. 9. The method of claim 8,
The copper ion precursor is nitrate (nitrate), chloride (chloride), bromide (bromide), iodide (iodide), nitrite (nitrite), sulfate (sulfate), acetate (acetate), sulfite (sulfite), acetylaceto A method for producing a methane oxidation catalyst, characterized in that at least one selected from acetylacetoante, hydroxide, and hydrates thereof. 9. The method of claim 8,
Step (b) is a method for producing a methane oxidation catalyst, characterized in that performed for 1 to 100 minutes at room temperature. 9. The method of claim 8,
Step (c) is a method for producing a methane oxidation catalyst, characterized in that it is performed for 1 to 100 minutes at room temperature. 9. The method of claim 8,
In the step (c), the zinc and copper ion precursors of the metal-organic structure represented by Chemical Formula 1 are mixed in a molar ratio of 1: 0.03 to 0.17. 9. The method of claim 8,
In step (c), the metal-organic structure and the copper ion precursor represented by Chemical Formula 1 are mixed in a ratio of 1 mg: 0.01 to 1 μmol.

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