KR20170107754A - Hollow Porous Carbon Composites Containing Metal Particles And Method For Preparing The Same - Google Patents

Abstract

The present invention relates to a hollow porous carbon composites containing metal particles and to a manufacturing method thereof, wherein the composites according to the present invention has low density, high dispersion ability, excellent dispersion stability, and excellent adsorption ability to be widely used for a wide range of applications such as catalysts, adsorbents, sensors, electrode materials, separation and purification agents, and storage materials for hydrogen and drugs, and also has excellent catalyst activity when used as a catalyst to minimize a decrease in activity even when reused. The method for producing a composite according to the present invention uses core-shell precursor particles having a polymer particle as a core to manufacture the core-shell precursor particles through a single-step heat treatment process, thereby having excellent process efficiency and saving cost and time.

Description

Technical Field [0001] The present invention relates to a hollow porous carbon composite material containing metal particles and a method for producing the hollow porous carbon composite material.

The present invention relates to a hollow porous carbon composite material containing metal particles and a method for producing the same.

Porous carbon particles are attracting attention as interesting materials that can be used in various fields including adsorbents, catalysts, hydrogen storage materials, drug delivery systems, and separation systems. There is a growing interest in improving the applicability of these carbon particles to new fields by fusing them with other functional materials. For example, there are magnetic carbon materials used for lithium ion batteries, supercapacitors, and pollutant separation. In order to synthesize these various carbon materials, a variety of materials such as electric arc, chemical vapor deposition (CVD), nanocasting, ultrasonic spray pyrolysis Methods have been developed. However, in order to synthesize the functional carbon material, development of a simpler manufacturing method is required.

Conventionally, the use of precursors has been proposed for producing the porous carbon particles. Recently, as a precursor, a method based on metal-organic frameworks (MOFs) has been used to produce porous carbon particles having high surface area and porosity The particles can be efficiently produced and thus attracting much attention.

For example, Korean Patent Registration No. 10-0644501 discloses a method for producing a hollow porous structure (carbon-aluminosilicate composite structure) having a wide specific surface area and multiple pores, There is a problem that the BET surface area is small, the pore size is large, and the manufacturing process is complicated.

Porous coordination polymers (CP) or organo-metallic skeletons (hereinafter also referred to as MOF) are of great interest due to their useful chemical and physical properties. Particularly, since chemical composition and porosity can be controlled, researches on them have been actively conducted in various practical applications such as gas storage, gas separation, optical and catalyst. Furthermore, the technology to make organo-metallic skeleton (MOF) into nano- or micro-sized co-polymer particles (CPP) has been developed and its usefulness has been further improved and expanded to biomedical applications.

In recent years, a variety of metal oxides can be produced using coordinated polymer particles (hereinafter also referred to as CPP) as a starting material. This can easily obtain complex and structured metal oxides by simply calcining CPP having a definite structure.

The organic-metal skeleton (MOF) is a porous material, and it is noted that nano- or micro-sized co-ordinated polymer particles are used as a template or as a precursor material to form nano- or micro-sized porous carbon material There is no specific practical application study on the method of producing the polypropylene.

On the other hand, metal nanoparticles are attracting much attention because they are usefully applied in catalysis, energy conversion and gas sensing. However, since the metal nanoparticles are agglomerated in reaction with high surface energy, the activity is significantly reduced after the reaction compared with the initial state. Therefore, it is necessary to develop a new structure complex in which metal nanoparticles are uniformly supported on a support such as silica, polystyrene or carbon so as to prevent aggregation of metal nanoparticles and maintain their activity.

Korean Patent No. 10-0644501.

An object of the present invention is to provide a carbon composite material having excellent catalytic activity, high activity even when reused, and less aggregation of metal particles, and a method for producing the same.

In order to solve the above problems,

Forming a porous carbon shell structure comprising an inner hollow,

The porous carbon shell may be formed of one or more metal particles selected from among gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir) and palladium Is dispersed.

Further, according to the present invention,

And mixing the metal precursor solution with the core-shell precursor particles having the polymer particles as a core and forming the organic-metal skeleton as a shell, and heat-treating the mixture.

INDUSTRIAL APPLICABILITY The composite according to the present invention has a low density and a high dispersing ability, is excellent in dispersion stability and excellent in adsorbing ability and widely used for a wide range of applications such as catalyst, adsorbent, sensor, electrode material, separation and purification, And is excellent in catalytic activity when used as a catalyst, and the reduction of activity is minimized even when reused. In addition, since the method of producing a composite according to the present invention can be manufactured through a single-step heat treatment process using core-shell precursor particles comprising polymer particles as a core, the process efficiency is excellent and cost and time can be reduced have.

Figure 1 is a simplified illustration of the process of making a composite according to the present invention.
FIG. 2 is a photograph of a composite according to Example 1, wherein FIGS. 2-a to 2-c are SEM photographs, 2-d and 2-e are TEM photographs, and 2-f is a STEM photograph.
FIG. 3 is a photograph of a measurement result of physical properties of the composite according to Example 1, wherein FIG. 3-a is an EDX spectrum graph, FIG. 3-b is a STEM photograph showing that gold particles are present in the composite, FIG. 3-d is a graph showing the presence of gold particles in the composite through a PXRD pattern. FIG.
4 is a photograph of a composite according to Example 2, wherein FIGS. 4-a and 4-b are SEM photographs, and 4-c and 4-d are STEM photographs.
FIG. 5 is a photograph of the results of physical property measurement of the composite according to Example 2, wherein FIG. 5-a is an EDX spectrum graph, FIG. 5-b is a STEM photograph showing that silver particles are present in the composite, FIG. 5D is a graph showing the presence of silver particles in the composite through a PXRD pattern. FIG.
6 is a photograph of a comparative example, wherein FIGS. 6A and 6B are TEM photographs, and FIG. 6C is a STEM photograph.
FIG. 7 is a graph of catalyst activity measurement results according to reaction times of Examples 1 and 2, where FIG. 7-a is the result of Example 1 and FIG. 7-b is the result of Example 2. FIG.
FIG. 8 is a graph showing the results of measurement of the catalytic activity of the comparative example.
FIG. 9 is a graph showing catalyst activity measurement results according to the reuse of Example 1. FIG.
10 is a photograph of the composite according to Example 1 after five times of reuse, wherein FIG. 10-a is a SEM photograph, and FIGS. 10-b and 10 -c are STEM photographs.
11 is a N ₂ adsorption isotherms of Examples 1 and 2 and Comparative Example where a is a comparative example, b is Example 2, and c is Example 1.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Therefore, the configurations shown in the embodiments described herein are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents And variations.

Hereinafter, the composite according to the present invention will be described in detail.

The composite according to the present invention,

Forming a porous carbon shell structure comprising an inner hollow,

The porous carbon shell may be formed of one or more metal particles selected from among gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir) and palladium May be a distributed structure.

The metal particles may be particles that are usefully used in catalysis, energy conversion, gas sensing, and the like. More specifically, noble metal particles such as gold (Au), silver (Ag), platinum (Pt), ruthenium The metal particles may be at least one of gold (Au), silver (Ag), gold (Au), silver Metal particles.

As an example, the complex according to the present invention may satisfy the conditions of the following general formula (1).

[Formula 1]

0.5 < D _in / D _out < 0.98

In the general formula 1,

D _in denotes the average diameter of the hollow formed inside the composite,

D _out means the average diameter of the composite.

The formula 1 may be a range of the ratio of the average diameter of the hollow to the average diameter of the composite, and specifically the ratio of the average diameter of the hollow to the average diameter of the composite is more than 0.5 to less than 0.98, 0.97, 0.6 to 0.95, 0.65 to 0.93, 0.7 to 0.91, or 0.75 to 0.9. When the ratio of the average diameter of the inner hollow to the average diameter of the composite satisfies the above range, excellent dispersibility and dispersion stability of the composite can be realized.

At this time, the average diameter of the composite according to the present invention may be 500 to 1500 nm. Specifically, the average diameter of the complex may be from 550 to 1450 nm, from 580 to 1400 nm, from 600 to 1350 nm, from 630 to 1300 nm, from 650 to 1250 nm, from 680 to 1200 nm, from 700 to 1150 nm, or from 720 to 1100 nm have. When the average diameter of the composite satisfies the above range, excellent dispersibility in the solution can be maintained for a long time.

As an example, the complex according to the present invention may satisfy the condition of the following general formula (2).

[Formula 2]

2 < D _s / D _m < 50

In general formula 2,

D _s means the average thickness of the porous carbon shell,

D _m means the average diameter of the metal particles.

The ratio of the average thickness of the porous carbon shell to the average diameter of the metal particles may be in the range of more than 2 to 50 , 2.5 to 45, 3 to 40, 4 to 35, 5 to 30, 6 to 25, 7 to 20, or 8 to 15. When the ratio of the average thickness of the porous carbon shell to the average diameter of the metal particles satisfies the above range, the metal particles can be well dispersed in the carbon shell without agglomeration, thereby maximizing the catalytic activity.

The average thickness of the porous carbon shell according to the present invention may be 50 to 250 nm. Specifically, the average thickness of the porous carbon shell may be 55 to 240 nm, 60 to 230 nm, 65 to 210 nm, 70 to 200 nm, 75 to 190 nm, 80 to 180 nm, or 85 to 150 nm. When the average thickness of the porous carbon shell according to the present invention is in the above range, agglomeration of the metal particles dispersed in the carbon shell can be prevented, thereby maximizing the catalytic activity.

In addition, the average diameter of the metal particles according to the present invention may be 1 to 20 nm. Specifically, the average diameter of the metal particles may be 1.5 to 19 nm, 2 to 17 nm, 2.5 to 15 nm, 3 to 13 nm, 3.5 to 12 nm, or 4 to 10 nm. When the average diameter of the metal particles is in the above range, it can be well dispersed in the carbon shell without agglomeration phenomenon, and thus high activity can be realized when the composite is used as a catalyst.

As an example, the composite according to the invention may have a BET surface area of 15 to 95 m ² / g and a pore volume of 0.05 to 0.15 cm ³ / g. Specifically, the BET surface area may range from 18 to 90 m ² / g, from 20 to 85 m ² / g, from 22 to 83 m ² / g, from 25 to 80 m ² / g or from 26 to 75 m ² / The volume of the pores may range from 0.08 to 0.145 cm ³ / g, from 0.1 to 0.143 cm ³ / g, or from 0.11 to 0.141 cm ³ / g. The composite according to the present invention has a structure in which metal particles are evenly dispersed in the porous carbon shell, so that the BET surface area in the above range can be satisfied.

As an example, the complex according to the present invention can satisfy the conditions of the following general formula 3 or general formula 4.

[Formula 3]

1 < I _{0m -268} / I _{4m -268} 15

[Formula 4]

0.01 <I _{0m -230} / I _{4m -230} <1

In the general formulas 3 and 4,

I _{0m -268} represents the intensity of the peak having the strongest intensity in the range of 268 ± 5 ㎚ when the absorbance of the mixture is measured immediately after mixing the aromatic nitric acid compound and the reducing agent,

I _{4m -268} shows the intensity of the strongest peak among the peaks existing in the range of 268 ± 5 ㎚ when the absorbance of the mixture after mixing the aromatic nitric acid compound, the reducing agent and the complex was measured for 4 minutes,

I _{0m -230} shows the intensity of the strongest peak in the range of 230 ± 5 ㎚ when measuring the absorbance of the mixture immediately after mixing the aromatic nitric acid compound and the reducing agent,

I _{4m -230} shows the intensity of the strongest peak among the peaks in the range of 230 ± 5 ㎚ when measuring the absorbance of the mixture after mixing the aromatic nitric compound, reducing agent and complex.

More specifically, the general formula 3 is the ratio of I _{0m -268} on, I _{4m -268} may be to a ratio range of _0m I _-268 to _-268 I _4m is specifically greater than 1 15 or less, 2 to 13, 3 to 11, 4 to 10, 5 to 9, or 6 to 8. Complex according to the present invention, by satisfying the range of the ratio I _{0m -268} to _-268 I _4m, it may implement a significantly improved catalytic activity.

In addition, the formula 4 is the ratio of I _{0m -268} to, _{I-4m 268} may be one of a ratio of a range of _0m I _-230 to _-230 I _4m specifically, greater than 0.01 less than 1, 0.2 to 0.9, 0.25 to 0.85, 0.3 to 0.8, 0.35 to 0.75, 0.4 to 0.7, or 0.45 to 0.65. Complex according to the present invention, by satisfying the range of the ratio I _{0m -230} to _-230 I _4m, it may implement a significantly improved catalytic activity.

The aromatic nitric acid compound used in the activity measurement of the complex in the present invention is not particularly limited, but may be specifically nitrobenzene, for example. The reducing agent is not particularly limited, but specific examples include NaBH ₄ Can be used.

As an example, the composite according to the present invention can satisfy the condition of the following general formula (5) when it is repeated n times (2? N? 10).

[Formula 5]

1? I _n / I _{n -1} ? 1.5

In the general formula 5,

I _n indicates the intensity of the peak having the strongest peak intensity in the range of 268 ± 5 ㎚ in the case of measuring the absorbance of the mixture after mixing the aromatic nitric acid compound, the reducing agent and the n repeatedly used complexes,

I _{n -1} represents the intensity of the peak having the strongest peak intensity in the range of 268 ± 5 ㎚ when the absorbance of the mixture after mixing with aromatic nitric acid compound, reducing agent and n-1 times repeatedly is measured.

Specifically, the formula 5 can be to a ratio range of about I _n I _{n -1,} a ratio of I _n-1 to I _n is specifically from 1 to 1.5, 1 to 1.4, 1 to 1.3 or 1.05 to 1.1. In the composite according to the present invention, the ratio of I _n to I _{n -1} satisfies the above range, so that even when the composite is repeatedly used, the catalyst activity is prevented from lowering, thereby providing a composite suitable for reuse.

Hereinafter, a method for producing a composite according to the present invention will be described in detail.

A method for producing a composite according to the present invention comprises:

And mixing the metal precursor solution with the core-shell precursor particles having the polymer particles as a core and forming the organo-metallic skeleton as a shell, followed by heat treatment.

As one example, the core-shell precursor particles are prepared by mixing a reaction mixture obtained by mixing a zinc metal and a 2-methylimidazole precursor solution capable of forming an organo-metallic skeletal shell on a polymer core particle surface-treated with a carboxyl group, Can be prepared by reacting.

As one example, the organo-metal skeleton may comprise a zeolite imidazolylate skeleton.

As one example, in the method for producing a composite according to the present invention, the core-shell precursor particles may be obtained by ultrasonically reacting the reaction mixture, then forming the core-shell To produce precursor particles, and centrifuging to obtain the precursor particles.

 As one example, the polymer particles according to the present invention may be selected from the group consisting of polystyrene, polyolefin, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polyalkyl (meth) And may be at least one member selected from the group consisting of polystyrene, polystyrene, and polystyrene.

As an example, the components constituting the metal precursor according to the present invention include at least one selected from the group consisting of Au, Ag, Pt, Ru, Os, Rh, Ir, And palladium (Pd). Specifically, the component constituting the metal precursor in the present invention may be gold or silver.

As one example, the metal precursor solution according to the present invention may be one in which the metal precursor is dissolved in an alkyl alcohol having 1 to 4 carbon atoms, specifically, methanol or ethanol.

As one example, the heat treatment according to the present invention can be performed in a temperature range of 500 to 1000 ° C, specifically, 550 to 950 ° C, 600 to 900 ° C, 650 to 850 ° C or 700 ° C .

As one example, the heat treatment according to the present invention can be carried out for 2 to 10 hours, specifically 3 to 8 hours, 4 to 6 hours or 5 hours.

Best Mode for Carrying Out the Invention Hereinafter, the present invention will be described in more detail with reference to examples and drawings based on the above description. The following examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

Example  1: gold ( Au ) Preparation of particles-dispersed composites

(1) polystyrene as core Core shell  Precursor particle production

A ZIF-8 precursor solution was prepared by dissolving 664 mg (8.1 mmol) of 2-methylimidazole and 240 mg (0.81 mmol) of Zn (NO ₃ ) ₂ .6H ₂ O in 32 mL of methanol. 120 mg of carbocylic acid-terminated silica surface-treated with a carboxyl group and the ZIF-8 precursor solution were mixed in an oil bath at 70 ° C and reacted using an ultrasonic disperser for 15 minutes. Then, the polystyrene &lt; RTI ID = 0.0 &gt; @ ZIF-8 &lt; / RTI &gt; core shell precursor particles precipitated by centrifugation were washed several times with methanol through re-dispersion and centrifugation cycles. In the centrifugation step, the pure nano-sized ZIF-8 particles were removed from the polystyrene @ ZIF-8 core shell precursor particles and then the growth process was repeated twice in fresh precursor solution to thicken the shell to obtain polystyrene @ ZIF -8 particles. In the present invention, 'polystyrene @ ZIF-8' may mean a core-shell precursor particle comprising polystyrene as a core.

(2) metal ions In the shell  Distributed Core shell  Particle manufacturing

47.6 mg of NaAuCl ₄ .2H ₂ O (0.12 mmol) was dissolved in 2 mL of ethanol and 50 mg of the polystyrene @ ZIF-8 particles prepared in the above procedure was added to the solution. The mixture was shaken at room temperature for 10 minutes, precipitated by centrifugation and the resulting particles were quickly washed with fresh ethanol and then vacuum dried.

(3) Production of a hollow composite in which gold particles are dispersed

In (2), the vacuum-dried particles were placed in a tube electric furnace, and the temperature was elevated at a heating rate of 5 ° C / min under a nitrogen condition, followed by calcination to a temperature of 700 ° C. After reaching the target temperature of 700 캜, heat treatment was performed for 5 hours. Then, the mixture was cooled to room temperature to obtain a hollow composite in which gold particles were dispersed.

Figure 1 is a simplified illustration of the process of making a composite according to the present invention.

"Polystyrene (Polystyrene) @ ZIF-8 'in the present invention means a core-shell precursor particles to a polystyrene in the core, and" polystyrene ^{@ ZIF-8 / Au 3 +} ' and 'polystyrene @ ZIF-8 / Ag ^+' is Refers to a core shell particle in which gold and silver ions are dispersed, and 'Au @ HCS' and 'Ag @ HCS' refer to a composite according to the present invention in which gold and silver particles are respectively dispersed in a porous carbon shell, &Quot; HCS &quot; means a particle having a porous porous carbon shell in which metal particles are not dispersed.

Hereinafter, the composite according to Example 1 will be described in detail with reference to the drawings.

FIG. 2 is a photograph of a composite according to Example 1, wherein FIGS. 2-a to 2-c are SEM photographs, 2-d and 2-e are TEM photographs, and 2-f is a STEM photograph.

According to Figures 2-a to 2-e, the average diameter of the composite according to Example 1 is about 800 to 950 nm, and according to Figures 2-c and 2-e, The average thickness of the carbon shell of the composite is about 97 to 110 nm. In FIG. 2-a, the image on the upper right is a photograph of the mixture of gold ions before (left) and after (right) heat treatment, showing that the ivory shell turned black after pyrolysis at 700 ° C.

FIG. 3 is a photograph of a measurement result of the physical properties of the composite according to Example 1, wherein FIG. 3-a is an EDX spectrum graph showing that gold particles are present in the composite according to Example 1. FIG. 3-b is a STEM photograph showing the presence of gold particles in the composite, and it can be confirmed that the average diameter of the gold particles is less than about 10 nm. FIG. 3 (c) is a HRTEM photograph showing the presence of gold particles in the composite, which shows a (111) lattice pattern due to gold particles and a d-spacing characteristic of gold at about 0.24 nm. FIG. 3-d is a graph showing the presence of gold particles in the composite through a PXRD pattern, where Au @ HCS is the composite according to Example 1, Pure HCS is a graph of particles without gold particles, The red bar represents the face-centered cubic structure of gold. In the present invention, 'HCS' may mean a hollow carbon sphere.

Example  2: silver ( Ag ) Manufacture of hollow composites with dispersed particles

(1) Polystyrene @ ZIF -8 Particle production

Polystyrene &lt; RTI ID = 0.0 &gt; @ ZIF-8 &lt; / RTI &gt;

(2) Addition of silver ion

4.07 mg of AgNO ₃ (0.024 mmol) was dissolved in 2 mL of methanol and 50 mg of the polystyrene @ ZIF-8 particles prepared in the above procedure was added to the solution. The mixture was shaken at room temperature for 30 minutes, precipitated by centrifugation, and the resulting particles were quickly washed with fresh methanol and then vacuum dried.

(3) the manufacture of a hollow composite in which particles are dispersed

In (2), the vacuum-dried particles were placed in a tube electric furnace, and the temperature was elevated at a heating rate of 5 ° C / min under a nitrogen condition, followed by calcination to a temperature of 700 ° C. After reaching the target temperature of 700 캜, heat treatment was performed for 5 hours. Then, the mixture was cooled to room temperature to obtain a hollow composite in which silver particles were dispersed.

Hereinafter, the composite according to Embodiment 2 will be described in detail with reference to the drawings.

4 is a photograph of a composite according to Example 2, wherein FIGS. 4-a and 4-b are SEM photographs, and 4-c and 4-d are STEM photographs. Referring to FIG. 4, it can be seen that the average diameter of the composite according to Example 2 is about 900 to 1000 nm, and the average thickness of the carbon shell is about 100 nm.

 FIG. 5 is a photograph of a physical property measurement result of the composite according to Example 2, wherein FIG. 5-a is an EDX spectrum graph, and it can be confirmed that silver particles are present in the composite according to Example 2. FIG. 5-b is a STEM photograph showing the presence of silver particles in the composite, which shows that the average diameter of the silver particles is less than about 10 nm. FIG. 5-c is a HRTEM image showing the presence of silver particles in the composite, which shows a (111) lattice pattern due to silver particles and a d-spacing characteristic of gold at about 0.24 nm. 5-d is a graph showing the presence of silver particles in the composite through a PXRD pattern, wherein the blue bar below represents the face-centered cubic structure of silver.

Comparative Example : Hollow HCS  Particle manufacturing

(1) Polystyrene @ ZIF -8 Particle production

Polystyrene &lt; RTI ID = 0.0 &gt; @ ZIF-8 &lt; / RTI &gt;

(2) Hollow type HCS  Particle manufacturing

The particles prepared in (1) above were placed in a tube electric furnace, and the temperature was elevated at a heating rate of 5 DEG C / min under a nitrogen condition, followed by calcination to 700 DEG C temperature. After reaching the target temperature of 700 캜, heat treatment was performed for 5 hours. Then, it was cooled to room temperature to obtain hollow HCS particles.

6 is a photograph of a HCS particle according to a comparative example, wherein FIGS. 6A and 6B are TEM photographs, and FIG. 6C is a STEM photograph.

Experimental Example  1: Measurement of catalytic activity

To measure the catalytic activity of the complex according to Examples 1 and 2 and Comparative Example, nitrobenzene (2.5 mM, 0.3 mL) was used as an aromatic nitric acid compound, NaBH ₄ (0.1 M, 9 mL) as a reducing agent and The complex according to Example 1 or 2 was mixed and the absorbance of the mixture was measured. At this time, the mixing amount of the complex according to Example 1 was 0.06 mg, and the mixing amount of the complex according to Example 2 was 0.03 mg. The absorbance of the mixture was measured by UV-vis spectra.

FIG. 7 is a graph of catalyst activity measurement results according to reaction times of Examples 1 and 2, where FIG. 7-a is the result of Example 1 and FIG. 7-b is the result of Example 2. FIG. Referring to Figure 7-a, nitrobenzene was not reduced before addition of the conjugate according to the invention (0 min, black line), indicating an absorbance of about 0.8 at a wavelength of about 268 nm, but the complexes were mixed At 4 minutes after the reaction (4 min, blue line), the absorbance of nitrobenzene was lowered to about 0.1 at a wavelength of about 268 nm, and the absorbance of aminobenzene reduced to nitrobenzene was about 230 nm And about 0.8 at wavelength. Also, referring to FIG. 7-b, the absorbance at a wavelength of about 268 nm was as high as about 0.8 before nitrobenzene was reduced before addition of the complex according to the present invention (0 min, black line) After 4 minutes of mixing (4 min, blue line), the absorbance of nitrobenzene at a wavelength of about 268 nm was lowered to about 0.1, and the absorbance of aminobenzene reduced to nitrobenzene was about 230 nm And about 0.9 at wavelength.

FIG. 8 is a graph showing the results of measurement of the catalytic activity of the comparative example. FIG. 8-a shows the results when only the reducing agent is used without the catalyst or the composite, and FIG. 8-b shows the results of mixing the HCS particles according to the comparative example with the catalyst. As a result, neither of the catalysts shown in Figures 8-a and 8-b showed catalytic activity over 10 minutes.

Therefore, it can be seen that the composite according to Examples 1 and 2 of the present invention contains gold particles or silver particles, so that the reduction from nitrobenzene to aminobenzene is performed rapidly in a short time of about 4 minutes, It has been confirmed that the complex according to the present invention realizes excellent catalytic activity.

Experimental Example  2: Measurement of catalytic activity by composite reuse

Nitrobenzene (2.5 mM, 0.3 mL) was used as the aromatic nitric acid compound, NaBH ₄ (0.1 M, 9 mL) was used as the reducing agent, and the catalyst of Example 0.06 mg of the complex according to 1 was mixed, and the absorbance of the mixture after 4 minutes passed was measured. The complex is then recovered, washed and again with nitrobenzene and NaBH ₄ After 4 minutes of mixing, the absorbance was measured. This procedure was repeated four times in total. At this time, absorbance was measured by UV-vis spectra.

FIG. 9 is a graph showing catalyst activity measurement results according to the reuse of Example 1. FIG. Referring to FIG. 9, it can be confirmed that the catalyst according to Example 1 exhibits almost the same catalytic activity as that used once even after four times of reuse.

10 is a photograph of the composite according to Example 1 after four times of reuse, wherein FIG. 10-a is a SEM photograph, and FIGS. 10-b and 10-c are STEM photographs. 10-a and 10-b, it can be seen that the shape of the composite remains unchanged even after four times of reuse. Also, referring to FIG. 10-c, it was confirmed that no agglomeration of the metal particles occurred. Accordingly, it has been confirmed that the composite according to the present invention can be easily reused without loss of the shape and activity of the composite even if it is reused many times.

Experimental Example  3: N ₂  Adsorption isotherm curves Specific surface area  And pore volume measurement

N ₂ adsorption isotherms were measured to determine the specific surface area and pore volume of Examples 1, 2 and Comparative Examples. The results are shown in Fig. 11, wherein a is a comparative example, b is Embodiment 2, and c is Embodiment 1. [ Referring to this graph, the BET surface area of Example 1 was about 27.0 m ² / g, the pore volume was about 0.12 cm ³ / g, the BET surface area of Example 2 was about 60.2 m ² / g, About 0.14 cm ³ / g, and the BET surface area and the pore volume of the comparative example were about 98.2 m ² / g and about 0.16 cm ³ / g, respectively. It can be confirmed that Examples 1 and 2 contain metal particles, so that the BET surface area and the pore volume are smaller than those of the comparative example.

Claims (15)

Forming a porous carbon shell structure comprising an inner hollow,
The porous carbon shell may be formed of one or more metal particles selected from gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir) &Lt; / RTI &gt;
The method according to claim 1,
Composites satisfying the conditions of the following general formula 1:
[Formula 1]
0.5 < D _in / D _out < 0.98
In the general formula 1,
D _in denotes the average diameter of the hollow formed inside the composite,
D _out means the average diameter of the composite.
3. The method of claim 2,
Wherein the average diameter of the composite is 500 to 1500 nm.
The method according to claim 1,
Composites satisfying the conditions of the following general formula 2:
[Formula 2]
2 < D _s / D _m < 50
In the general formula 1,
D _s means the average thickness of the porous carbon shell,
D _m means the average diameter of the metal particles. 5. The method of claim 4,
Wherein the porous carbon shell has an average thickness of 50 to 250 nm.
The method according to claim 1,
Wherein the composite has a BET surface area of 15 to 95 m ² / g and a volume of pores of 0.05 to 0.15 cm ³ / g.
The method according to claim 1,
A complex satisfying the following general formula 3 or general formula 4:
[Formula 3]
1 < I _{0m -268} / I _{4m -268} 15
[Formula 4]
0.01 <I _{0m -230} / I _{4m -230} <1
In the general formulas 3 and 4,
I _{0m -268} represents the intensity of the peak having the strongest intensity in the range of 268 ± 5 ㎚ when the absorbance of the mixture is measured immediately after mixing the aromatic nitric acid compound and the reducing agent,
I _{4m -268} shows the intensity of the strongest peak among the peaks existing in the range of 268 ± 5 ㎚ when the absorbance of the mixture after mixing the aromatic nitric acid compound, the reducing agent and the complex was measured for 4 minutes,
I _{0m -230} shows the intensity of the strongest peak in the range of 230 ± 5 ㎚ when measuring the absorbance of the mixture immediately after mixing the aromatic nitric acid compound and the reducing agent,
I _{4m -230} shows the intensity of the strongest peak among the peaks in the range of 230 ± 5 ㎚ when measuring the absorbance of the mixture after mixing the aromatic nitric compound, reducing agent and complex.
The method according to claim 1,
Composite satisfying the condition of the following general formula (5) when repeatedly used n times (2? n? 10):
[Formula 5]
1? I _n / I _{n -1} ? 1.5
In the general formula 5,
I _n indicates the intensity of the peak having the strongest peak intensity in the range of 268 ± 5 ㎚ in the case of measuring the absorbance of the mixture after mixing the aromatic nitric acid compound, the reducing agent and the n repeatedly used complexes,
I _{n -1} represents the intensity of the peak having the strongest peak intensity in the range of 268 ± 5 ㎚ when the absorbance of the mixture after mixing with aromatic nitric acid compound, reducing agent and n-1 times repeatedly is measured.
And mixing the metal precursor solution with the core-shell precursor particles having the polymer particles as a core and forming the organo-metallic skeleton as a shell, and heat-treating the mixture.
10. The method of claim 9,
The core-shell precursor particles are produced by subjecting a reaction mixture obtained by mixing a zinc metal and a 2-methylimidazole precursor solution capable of forming an organo-metallic skeletal shell to a polymer core particle surface-treated with a carboxyl group by ultrasonic reaction &Lt; / RTI &gt;
10. The method of claim 9,
The polymer particles may be selected from the group consisting of polystyrene, polyolefin, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polyalkyl (meth) acrylate, &Lt; / RTI &gt; or more.
10. The method of claim 9,
The component constituting the metal precursor may be any one selected from gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir) and palladium &Lt; / RTI &
10. The method of claim 9,
Wherein the metal precursor solution is prepared by dissolving the metal precursor in an alkyl alcohol having 1 to 4 carbon atoms.
10. The method of claim 9,
Wherein the heat treatment is performed in a temperature range of 500 to 1000 占 폚.
10. The method of claim 9,
Wherein the heat treatment is performed for 2 to 10 hours.

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