KR20050018200A - HCMS capsule structures containing metal nanoparticles within the hollow core, and their preparation method - Google Patents

Abstract

PURPOSE: To provide a hollow core with mesoporous shell capsule structure containing nano-particles within hollow core, of which a size of macro-pore, a thickness of a shell, a size of meso-pore, and a size of a metal nano-particle are easily controlled, and a method for preparing thereof. CONSTITUTION: The method comprises the steps of: (a) synthesizing metal nano-particles; (b) coating the surface of the synthesized metal nano-particles with silica to prepare M$À silica containing the metal nano-particles therein; (c) forming mesoporous shell on the outside of the M$À silica to prepare solid core with mesoporous shell(SCMS) silica particles; (d) injecting polymer precursor and polymerization initiator into meso pores of the SCMS silica particles to prepare polymer-M$À silica complex; and (e) removing silica from the polymer-M$À silica complex to prepare hollow core with mesoporous shell containing metal nano-particles in hollow core.

Description

HCMS capsule structures containing metal nanoparticles within the hollow core, and their preparation method

The present invention has a uniform sized mesoporous periphery, a porous capsule structure containing gold (Au) or other metal nanoparticles inside a hollow core (HCMS) structure of a constant size. And a method for producing the same.

Recently, there have been several reported papers on the synthesis of porous carbon materials using templates as in the present invention. A technique for synthesizing new macroporous carbon materials having regular and constant size by injecting precursors such as carbohydrates or polymer monomers into a colloidal crystal template in which spherical silica particles are stacked, and then removing the template. This has been reported [AA Zajhidov, RH Baughman, Z. Iqubal, C. Cui, I. Khayrullin, SO Dantas, J. Matri and VG Ralchenko, Science 1998 , 282 , 897; JS Yu, SB Yoon and GS Chai, Carbon 2001 , 39 (9) , 1442; JS Yu, SJ Lee and SB Yoon, Mol. Cryst. Liq. Cryst ., 2001 , 371 , 107]. In addition, in order to utilize the chemical and physical properties of gold nanoparticles, the method of preparing spherical silica (Au @ SiO ₂ ) nanoparticles centered on the gold nanoparticles and the manufactured spherical silica nanoparticles were used as Synthesis studies have been reported [Luis M. Liz-Marzan, Michael Giersig and Paul Mulvaney, Langmuir, 1996, 12, 4329; Benito Rodringuez-Gonzalez, Veronica Salgueirino-Maceira, Florencio Garcia-Santamaria and Luis M. Liz-Marzan, Nano Letters , 2002 , 2 (5) , 471]. In addition, a technique for producing hollow polymer and carbon nanocapsule structures having a uniform mesoporous outer surface has been reported by the researchers [SB Yoon, K. Sohn, JY Kim, CH Shin, JS Yu and T. Hyeon] Advanced Materials 2002 , 14 (1) , 19-21; JS Yu and T. Hyeon "Synthesis of nanoporous capsule-structure body having hollow core with mesoporous shell" Korean Patent Application number 10-2002-0008376. In particular, the hollow carbon nanocapsule structure is expected to be applicable to various fields. However, since the hollow inside is empty, its application is limited.

Accordingly, there is a need for the preparation of a hollow double-porous nanocapsule structure material having nanoporosity of uniform size in its outer shell and containing metal nanoparticles with specific activity and functionality therein. Hollow porous nanocapsule structures including metal nanoparticles therein can be applied to various applications such as catalysts, adsorbents, separation and purification processes, hydrogen storage and release, drug storage and transport materials, electrode materials, and sensors.

However, in the above-described conventional technique, since there is no uniformly sized metal nanoparticles in the center of silica used as a template, spherical carbon having a mesoporous outline containing uniformly sized metal nanoparticles inside the hollow form is used. Nanocapsules and ceramic nanocapsules are not available.

A first object of the present invention is to provide a hollow core with mesoporous shell (HCMS) type polymer / carbon / ceramic capsule structure including metal nanoparticles in a macro hollow interior.

It is a second object of the present invention to provide a method for producing an HCMS type polymer capsule structure, which includes metal nanoparticles inside a macro hollow.

It is a third object of the present invention to provide a method for producing an HCMS type carbon capsule structure, which includes metal nanoparticles in a macro hollow interior.

It is a fourth object of the present invention to provide a method for producing an HCMS type ceramic capsule structure, which includes metal nanoparticles in a macro hollow interior.

Accordingly, the present inventors have made intensive studies to solve these problems, and have found that the HCS capsule structure including the metal nanoparticles in the hollow can be manufactured by the following method and completed the invention.

HCMS type polymer / carbon / ceramic nanocapsule structure including metal nanoparticles in a hollow interior according to the first object of the present invention has a thickness in the range of 10 to 200 nm and a polymer in which mesopores with a diameter of 2 to 8 nm are uniformly distributed. It is a double-porous structure characterized in that it comprises metal nanoparticles of 0.5 to 50nm in diameter in a hollow of 30 to 2000nm in diameter surrounded by a carbon or ceramic shell. 4 shows a TEM photograph showing an example of an HCMS type polymer / carbon / ceramic nanocapsule structure including metal nanoparticles in a hollow interior according to the present invention.

The method (method 1) of preparing the polymer capsule structure according to the second object of the present invention includes the following steps:

A) synthesizing metal nanoparticles;

B) coating silica on the surface of the synthesized metal nanoparticles to synthesize silica particles (M @ silica) containing metal nanoparticles therein;

C) synthesizing SCMS (solid core with mesoporous shell) silica particles by forming a mesoporous shell on the outside of the synthesized M @ silica;

D) injecting a polymer precursor and a polymerization initiator into the mesopores of the outer shell of the SCMS silica particles and proceeding the polymerization reaction to synthesize a polymer-M @ silica template complex; And

E) preparing a HCMS polymer nanocapsule structure including metal nanoparticles in the hollow by removing silica from the polymer-M @ silica template composite.

The method (method 2) of preparing a carbon capsule structure according to the third object of the present invention includes the following steps:

A) synthesizing metal nanoparticles;

B) coating silica on the surface of the synthesized metal nanoparticles to synthesize silica particles (M @ silica) containing metal nanoparticles therein;

C) synthesizing SCMS silica particles by forming a mesoporous shell on the outside of the M @ silica synthesized above;

D) injecting a polymer precursor and a polymerization initiator into the mesopores of the outer shell of the SCMS silica particles and proceeding the polymerization reaction to synthesize a polymer-M @ silica template complex;

E) carbonizing the polymer-M @ silica template composite to synthesize a carbon-M @ silica template composite; And

F) preparing a HCMS carbon nanocapsule structure including metal nanoparticles in the hollow by removing silica from the carbon-M @ silica template composite synthesized above.

The method (method 3) of manufacturing a ceramic capsule structure according to the fourth object of the present invention includes the following steps:

A) synthesizing metal nanoparticles;

B) coating silica on the surface of the synthesized metal nanoparticles to synthesize silica particles (M @ silica) containing metal nanoparticles therein;

C) synthesizing SCMS silica particles by forming a mesoporous shell on the outside of the M @ silica synthesized above;

D) injecting a polymer precursor and a polymerization initiator into the mesopores of the outer shell of the SCMS silica particles and proceeding the polymerization reaction to synthesize a polymer-M @ silica template complex;

E) carbonizing the polymer-M @ silica template composite to synthesize a carbon-M @ silica template composite;

F) preparing a HCMS carbon nanocapsule structure including metal nanoparticles in the hollow by removing silica from the carbon-M @ silica template composite synthesized above;

G) injecting a ceramic precursor into the mesopores of the outer surface of the synthesized carbon-M @ silica template composite and converting the ceramic precursor into a ceramic to synthesize the ceramic-M @ carbon composite; And

H) preparing a HCMS ceramic nanocapsule structure including metal nanoparticles in the hollow by removing carbon through a sintering reaction.

Summarizing the manufacturing method according to the first to third objects of the present invention as follows.

That is, after uniformly synthesizing spherical metal (gold is typical) nanoparticles, silica is coated on the surface of the synthesized metal (M: metal) nanoparticles, and various sizes of M- including metal nanoparticles at the center thereof are included. Silica (M @ SiO ₂ ) spherical nanoparticles are synthesized. On the surface of the synthesized spherical M-silica nanoparticles, a mesoporous outer portion was attached, and the shell portion was prepared with a solid core with mesoporous shell (M @ SCMS) SiO ₂ template particles having mesopores. Next, the polymer precursor is injected into the mesoporous outer periphery of the synthesized silica template. At this time, if the precursor is a monomer, the polymer precursor is molded by polymerization, and then polymerized to obtain a polymer-M @ silica template composite. The silica mold is selectively removed using a (HF) solution or a sodium hydroxide (NaOH) or potassium hydroxide (KOH) solution to obtain a polymer capsule structure containing metal nanoparticles in the hollow. On the other hand, after the carbon-M @ silica composite is obtained by carbonizing the polymer-M @ silica composite at a temperature of 900 to 1000 ° C. under an inert gas, the silica mold is melted when the silica mold is removed in the above manner. The pores of a certain size are formed in the place, so that the center has a metal nanoparticle inside the macro pores of a certain size, and the outer shell is a mesoporous spherical new double-porous HCMS carbon capsule structure. Furthermore, by using the HCMS porous carbon capsule containing the obtained metal nanoparticles as a template, it is injected into the mesoporous pores as a precursor of silica or another inorganic ceramic material and replicated once more by the sol-gel method. After the second replication, the carbon structure template was burned and removed from the air to prepare a new porous HCMS ceramic capsule containing gold nanoparticles therein.

Hereinafter, a method of manufacturing HCMS polymer / carbon / ceramic nanocapsule structure including metal nanoparticles in a hollow interior according to the present invention shown in FIG. 1 will be described in more detail at each step. In the description of each step below, the steps not shown for each of the three methods of manufacturing the HCMS nanocapsule structure including the metal nanoparticles in the hollow are common to each method.

1) Synthesis of Metal Nanoparticles (Step A)

Synthesis method of metal nanoparticles, which is the first step in the method of manufacturing HCMS polymer / carbon / ceramic nanocapsule structures including metal nanoparticles in the hollow interior of the present invention, is known in the art [Au, BV Enuestuen and John Jurkevich, J. Am. Chem. Soc ., 1963 , 85 , 3317]. For example, a method in which a reducing agent is added to an aqueous solution of a water-soluble metal salt to precipitate a metal is used. The metal nanoparticles can be selectively synthesized in a predetermined size having a diameter of 50 nm or less, usually 0.5 to 50 nm, and in addition to gold, methods for synthesizing various other metal nanoparticles such as silver, platinum, and cobalt are also known. (Ag) For nanoparticles, see Thearith Ung, Luis M. Liz-Marzan and Paul Mulvaney, J. Phys. Chem. B 1999 , 103 , 6770, Isabel Pastoriza-Santos and Luis M. Lis-Marzan, Langmuir , 1999 , 15 , 948 and the like; For platinum (Pt) nanoparticles, see Arnim Henglein, J. Phys. Chem. B 2000 , 104 , 2201, S.-Y. Zhao, S.-H. Chen, S.-Y. Wang, D.-G. Li and H.-Y. Ma, Langmuir , 2002 , 18 , 3315 et al.].

Since the surface of the metal nanoparticles synthesized by the method as described above is electrically charged, silica can be coated on the surface of the particles in the following steps, and finally, various compounds are bonded to the surface of the metal nanoparticles. Make it available for use. Since the surface of the gold nanoparticles synthesized using a reducing agent in an aqueous solution is electrically negative, this property can be used to coat silica on the surface of the gold nanoparticles.

2) synthesizing silica particles (M @ silica) containing metal nanoparticles therein (step B)

The method of coating silica on the outside of the surface of the spherical metal nanoparticles having a uniform size obtained in the above step is known technique, for example, Luis M. Liz-Marzan, Michael Giersig and Paul Mulvaney, Langmuir, 1996 , 12, 4329, to improve the method described in Korean Patent Application No. 10-2000-0057082, the inventor of which has already applied for the patent (the contents described in the above patent application are incorporated herein in their entirety). In addition, it is possible to vary the size of the total M @ silica particles by varying the thickness of the silica coated according to the patented method. Depending on the size of the M @ silica particles, the size of the macropores in the polymer / carbon / ceramic capsule, which is the final product, may be adjusted.

The size of the spherical M @ silica particles can be easily prepared in a range of 30 to 2000 nm or more in a constant size depending on the synthesis conditions.

3) Synthesis of M @ SCMS Silica Particles (Step C)

The technology for synthesizing M @ SCMS silica particles by forming a mesoporous shell on the outside of the surface of spherical M @ silica particles having a uniform size synthesized in the above step is Korean Patent Application No. 10-2002 The method disclosed in -0008376 (the entire contents disclosed in this patent application is incorporated herein by reference) is used.

4) Synthesis of Polymer-M @ silica Template Complex (Step D)

The method for synthesizing the polymer-M @ silica template composite by injecting a polymer precursor into the mesopores of the M @ SCMS silica particles prepared in the above step is mentioned in the above-mentioned, Korean Patent Application No. 10- Follow the method described in 2002-0008376.

Polymer precursors used to form the outer shell with mesopores include, but are not limited to, divinylbenzene (DVB), acrylonitrile, phenolic resin, vinyl chloride, vinyl acetate , Styrene, methacrylate, methyl methacrylate, ethylene glycol dimethacrylate, furfuryl alcohol, resorcinol-formaldehyde (RF), urea, melamine, sugar and general The same or similar capsule structure can also be prepared by using a compound represented by the formula CH ₂ = CRR ', wherein R and R' are an alkyl group or an aryl group, or mesophase pitch. Included are those that form graphitic carbon by a carbonation reaction. In the case of using divinylbenzene as a precursor, Au @ SCMS SiO ₂ (silica) particles may be directly used as a template.

As a radical polymerization initiator used for superposition | polymerization of the said polymer monomer, although it is not limited to this, azobisisobutyronitrile (AIBN), t-butyl peracetate, benzoyl peroxide, acetyl peroxide, and lauryl peroxide, It may be used by selecting from among initiators used in the same conventional radical polymerization reaction.

5) Synthesis of Carbon-M @ silica Template Complex (Step E of Methods 2 and 3)

The carbon-M @ silica template composite is prepared by carbonizing the polymer in the inert gas atmosphere of the polymer-M @ silica template composite synthesized in the above step at a temperature of about 900 to 1000 ° C. A description of this process is described in detail in Korean Patent Application No. 10-2002-0008376 filed by the inventors, the contents of which are hereby incorporated by reference in their entirety.

6) Preparation of polymer and carbon nanocapsule structure having mesoporous shells and metal nanoparticles in hollow form (step E of method 1, step F of method 2 and step F of method 3)

By removing silica from the polymer-M @ silica template composite synthesized in step D of method 1 or the carbon-M @ silica template composite synthesized in step E of method 2, it has a mesoporous shell and contains metal nanoparticles in the hollow form. To prepare a polymer or carbon nanocapsule structure. This step is described in detail in Korean Patent Application No. 10-2002-0008376 to which the inventor has applied for a patent, the contents of which are incorporated by reference in the present specification as a whole.

7) Synthesis of Ceramic-M @ carbon Composite (Step G of Method 3)

The ceramic precursor was injected into mesopores distributed on the outer surface of the HCMS carbon nanocapsule structure including the metal nanoparticles in the hollow core synthesized in step F of Method 3, and then the ceramic precursor was converted to ceramic to synthesize a ceramic-M @ carbon composite. do. Types of ceramics that can be manufactured may include TiO ₂ , SnO ₂ , ZnO ₂ , ZrO _2, and Al ₂ O ₃ , but are not limited thereto.

A ceramic precursor which can be used in the step, in the case of ceramic, silica, for example, there are such as TEOS (tetraethoxysilane), TBOS (tetrabutyl orthosilicate), TMOS (teramethoxysilane), SiCl 4 (tetrchlorosilane), the ceramic is TiO ₂ Titanium (IV) butoxide, titanium (IV) isopropoxide, titanium (IV) chloride, and the like If the SnO ₂ may include tin chloride (IV) (tin (IV) chloride), tin (IV) tert- butoxide (tin (IV) tert -butoxide) , when the ceramic is ZnO ₂ is acetic acid zinc (zinc acetate), (and the like, zinc chloride), if ZrO ₂ is zirconium (IV) tert- butoxide (zirconium (IV) chloride, zinc tert -butoxide), zirconium (IV) chloride (zirconium (IV) chloride), zirconium (IV) ethoxide (zirconium (IV) ethoxide), zirconium (IV) propoxide (zirconium (IV) propoxide).

The ceramic precursor is, for example, when TEOS is used as a silica precursor, the nanocapsules infused with the ceramic precursor are reacted with HCl / H ₂ O steam or NH ₄ OH / H ₂ O steam at 50-100 ° C. or room temperature. Is exposed to air in the sample and converted to silica by hydrolysis through reaction with moisture in the air. As the ceramic precursor, precursors such as titanium (IV) alkoxide, tin (IV) alkoxide or zirconium (IV) alkoxide are converted to ceramic under the above conditions. When SiCl ₄ and TiCl ₄ are used as ceramic precursors, the ceramic precursors are deposited in a vapor phase and then reacted with moisture in the air to be converted into ceramics. Precursors such as zinc acetate or zinc chloride are dissolved in a solvent and injected into mesopores distributed outside the HCMS carbon nanocapsule structure, and the temperature is increased by 5 ° C./min in an inert gas (nitrogen) atmosphere in a tube furnace at 550 ° C. The temperature is raised to and maintained at the above conditions for 3-4 hours to convert to ceramics.

8) preparing HCMS ceramic nanocapsule structure comprising metal nanoparticles in hollow interior (step H of method 3)

The ceramic-M @ carbon composite prepared in the above step was sintered at about 550 ° C. for about 1 hour using a tube furnace or other similar heat treatment equipment under an inert gas atmosphere such as N ₂ or Ar, followed by oxygen or Heat treatment for 5 to 7 hours in an air atmosphere, or heat treatment for the same temperature and time in the air or oxygen atmosphere from the beginning to synthesize the HCMS ceramic nanocapsule structure including the metal nanoparticles in the hollow interior.

According to the method of the present invention, a novel spherical HCMS of uniform size comprising fine nanoparticles of various metals having unique activity inside the hollow structure by an economical and simple process by using a variety of inexpensive commercially available precursors Polymer / carbon / ceramic nanocapsules can be obtained, and these nanocapsules can be applied to various applications such as catalysts, adsorbents, separation and purification processes, hydrogen storage and release, drug storage and transport materials, electrode materials and sensors.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1

Au nanoparticles, Au @ SiO ₂  Spherical Particles and Au @ SCMS SiO ₂  Synthesis of particles

1.Synthesis of Gold (Au) Nanoparticles and Au @ SiO ₂ Spherical Particles

Gold was selected as the active metal contained in the macro hollow, and spherical gold nanoparticles were synthesized as follows.

10 ml of 1.0 mg / mL HAuCl ₄ solution was added to 180 ml of tertiary distilled water under stirring, followed by stirring at 100 ° C. for 10 minutes, and then 10 ml of 10.0 mg / ml aqueous solution of sodium citrate was added and stirred at 100 ° C. for 1 hour. The mixture was cooled to room temperature to obtain an aqueous solution in which deep red gold nanoparticles were dispersed. Electron micrographs of the prepared gold nanoparticles are shown in FIG. 2A (TEM photograph). In FIG. 2, it can be seen that the gold nanoparticles have a uniform size of about 18 nm.

In addition to gold, nanoparticles of other active metals such as silver (Ag), platinum (Pt), and cobalt (Co) can also be synthesized with a uniform size of 50 nm or less based on known methods.

3 ml of 1 mM AP-TMS {(3-aminopropyl) trimethoxysilane} aqueous solution was added to 400 ml of the gold nanoparticle-dispersed solution prepared above, and stirred at room temperature for 15 minutes, and then sodium metasilicate having a pH of 10-11.5 (Sodium metasilicate: Na ₂ SiO ₃ · xH ₂ O, x ≒ 5-9) 16 ml of aqueous solution was added thereto, and stirred at room temperature for 24 to 36 hours. As a result, a thin silica layer of about 4 nm or less was coated on the surface of the gold (Au) nanoparticles (see FIG. 2B). To the solution was added 1.7 l of 4 times the 99.9% ethanol solution in volume ratio and stirred at room temperature for 10 minutes, followed by 8.2 ml of 28% NH ₄ OH solution and further stirred at room temperature for 10 minutes with 98 wt% of tetraoxysilane (TEOS: 2 ml of tetraethoxysilane) was added and stirred at room temperature for 24 hours to obtain gold @ silica nanoparticles with a diameter of 200 nm.

In the above, the size of the gold (Au) @ silica (SiO ₂ ) nanoparticles can be adjusted by adjusting the amount of TEOS according to the method described in Korean Patent Application No. 10-2000-0057082 of the present inventors.

2. Synthesis of Au @ SCMS SiO ₂ Particles with Mesoporous Shell and Gold Nanoparticles Inside Hollow Type

Various meso as to adjust the molar ratio of C ₁₈ and the number of moles TEOS / C ₁₈ of -TMS -TMS as for each about 1.5 g of the spherical synthesized by the method Au @ SiO ₂ nanoparticles in the table 1 shown in Table 1 Au @ SCMS SiO ₂ nanoparticles with mesoporous shells with pore sizes were prepared. An electron micrograph (TEM photograph) of Au @ SCMS silica prepared in Preparation Example 5 is shown in FIG. 3B. In addition, the pore size of the obtained silica particles are also shown in Table 1.

Manufacturing example number Amount of C18-TMS in the Mixture (mmol) Molar ratio of TEOS / C18-TMS Pore size (nm) One 0.47 46.8 1.7 2 1.18 18.6 2.0 3 2.36 9.3 3.6 4 3.54 6.2 3.6 5 4.72 4.7 3.8

Example 2

Preparation of Polymer Nanocapsule Structures and Carbon Nanocapsule Structures Containing Gold Nanoparticles Inside Hollow Type Using Divinylbenzene as Precursor

Au @ SCMS silica particles with shells with mesopores of about 2.9 nm in Au @ SiO ₂ spherical silica having a diameter of about 200 nm were used as templates and divinylbenzene and azobisisobutyronitrile ( The aznobisisobutyronitrile (AIBN) radical initiator was mixed and injected into SCMS mesopores, and then polymerized at 70 ° C. for 12 hours to obtain a divinylbenzene polymer-Au @ HCMS SiO ₂ template complex. At this time, the molar ratio of the polymer monomer and the radical initiator was about 25: 1. In addition, a part of the obtained divinylbenzene polymer-Au @ HCMS SiO ₂ composite was heated under an inert gas (nitrogen or argon) for 7 hours in a temperature range of 900 to 1000 ° C. to carbonize the polymer, followed by carbon-Au @ HCMS SiO ₂ The complex was obtained. 1 g of each of the divinylbenzene polymer-Au @ HCMS SiO ₂ template composite and the carbon-Au @ HCMS SiO ₂ composite obtained above was dispersed in 40 ml of distilled water, and 10 ml of 50 wt% aqueous HF solution was added thereto at 25 ° C. Stirring for 12 hours to remove the silica template to obtain a polymer or carbon nanocapsules containing gold nanoparticles in the hollow. Table 2 shows the specific amounts of the additives used. An electron micrograph of the resulting porous carbon capsule is shown in FIG. 4 (TEM photograph). Table 2 and Figure 4 show Au @ HCMS carbon capsules containing gold nanoparticles in a new hollow interior synthesized in the present invention using Au @ SCMS SiO ₂ particles of about 200 nm size. Here, the central part containing gold nanoparticles has a macropore of about 195 nm and the outer part has a double-pore spherical capsule structure in which uniform mesopores of 4.3 nm are distributed. In this result, the size of the central macropores slightly smaller than the spherical Au @ SiO ₂ particles used as the template is caused by shrinkage during the polymer reaction and the carbonation reaction.

DVB (ml) / mold g AIBN (g) / template g HCMS Carbon Capsule Core Macropores Size (nm) Size of mesopores in HCMS carbon capsule shells (nm) 4 0.1845 195 4.3

Example 3

Preparation of Polymer Nanocapsule Structures and Carbon Nanocapsule Structures Containing Gold Nanoparticles in a Hollow Form Using Phenolic Resin as a Precursor

When phenol resin is used as a precursor, an acid catalyst is required for the polymerization of monomers. To this end, the synthesized Au @ SCMS SiO ₂ particles were first dried at 150 ° C. for 12 hours, and then 1 g of dried Au @ SCMS SiO ₂ was added to an aqueous solution of AlCl ₃ (0.34 g) dissolved in 10 ml of distilled water. Stir for 30 minutes and sonicate for another hour. Au @ SCMS SiO ₂ template particles treated with Al ions separated by centrifugation or sedimentation were dried again in a 150 ° C. oven. When the dried Au @ SCMS silica template particles were calcined in the air at 500 ° C. for 4 hours in the air, aluminum (Al) ions were implanted on the silica surface and added to the silica surface, and the added aluminum (Al) was added. This results in the formation of acidic sites on the silica surface. The acid spot was formed on the surface of the Au @ SCMS aluminosilicate thus formed, and 99 wt% of phenol was added thereto, and the mixture was poured into a vacuum reaction vessel, reduced to 0.3 mm Hg, heated at 140 ° C. for 12 hours, and 95 wt% of formaldehyde was added. It heated at 120 degreeC for about 6 hours. Phenol and formaldehyde used above were used 0.20 g and 0.16 g for 1 g of Au @ SCMS SiO ₂ template particles, respectively. Phenol resin-Au @ SCMS aluminosilicate was polymerized by polymerizing the polymer precursor by raising the temperature to 160 ° C. by raising the temperature by 1 ° C./min in a nitrogen atmosphere in a tube furnace in a tube furnace. Template complexes were synthesized. In addition, a portion of the complex was heated to 5 ° C./min in an inert gas (nitrogen) atmosphere in a conduit to raise the temperature to 1000 ° C., and maintained for 7 hours under the above conditions to obtain a carbon-Au @ SCMS aluminosilicate template complex. 1 g of each of the phenol resin-Au @ SCMS aluminosilicate template complex and the carbon-Au @ SCMS aluminosilicate template complex was dispersed in 40 ml of distilled water, 10 ml of 50 wt% HF solution was added thereto, and stirred at 25 ° C. for 12 hours. The silica mold portion was removed and the polymer nanocapsule and carbon nanocapsule structure in which the gold nanoparticles were hollow were separated by filtration, and then dried. In this way, the use of a template in which acid sites are formed on the surface of SCMS silica can be used in addition to the precursor phenol resin, and various other precursors polymerized in an acid catalyst such as furfuryl alcohol and resorcinol-formaldehyde (RF).

Example 4

Preparation of Carbon Nanocapsule Structures Containing Gold Nanoparticles Inside Hollow Type Using Various Carbohydrates as Precursors

When using carbohydrates such as sucrose as a precursor, a mixture of sucrose and sulfuric acid prepared by mixing at 25 ° C. in a ratio of 1 g sucrose, 0.5 g water and 0.1 g of 95% sulfuric acid is used as a carbon precursor. do. 1 g of the dried Au @ SCMS silica particle template is mixed with a 3.2 g carbon precursor solution prepared under the above conditions at room temperature. After adding the carbon precursor mixture solution to the mesoporous of pre-dried Au @ SCMS silica particles, the carbohydrate-Au @ SCMS silica template composite was gradually heated to 100 ° C. for 2 hours, and maintained at the same temperature for about 5 hours. I was. When the mixture of the carbon precursor mixture and the Au @ SCMS silica particles is heated to 100 ° C., the carbon precursor solution is added to mesoporous by capillary action, and at this temperature, the carbohydrate is dehydrated by sulfuric acid and carbonized. After the complex was sufficiently dried in an oven at 100 ° C. for 5 hours, the process was repeated once more, and then the dried complex was heated up to 1000 ° C. at 5 ° C./min in an inert gas (nitrogen) atmosphere, under the above conditions. Hold for 7 hours. After dispersing 1 g of the carbon-Au @ SCMS silica template composite obtained under the above conditions in 40 ml of distilled water, 10 ml of 50 wt% HF solution was added thereto, and stirred at 25 ° C. for 12 hours to remove the silica mold portion. The porous carbon nanocapsules in the center were separated and dried. In addition to sucrose, various carbohydrates such as glucose and gyro may be used as precursors. These precursors correspond to the equivalents of sucrose used in the above examples.

Example 5

Fabrication of Ceramic Nanocapsule Structures with Mesoporous Outer Shell and Containing Gold Nanoparticles

The Au @ HCMS carbon nanocapsule structure prepared in Example 2-4 was dried in a 100 ° C. vacuum oven. Using a dried carbon nanocapsule structure as a template, inject a tetraethoxysilane (TEOS) solution, a ceramic precursor, into the nanopores of the outer shell, and then put the nanocapsule structure and the ceramic precursor mixture in a vacuum reactor. Maintain vacuum for time. The dried inert gas (N ₂ or Ar) is injected into the vacuum reaction vessel, and the nanocapsule structure and the ceramic precursor mixture are centrifuged to remove excess ceramic precursors. Ceramic nanocapsule composites were prepared by using a method of reacting nanocapsules injected with ceramic precursors with HCl / H ₂ O vapor at 100 ° C. for 1 day. The prepared composite is sintered at 550 ° C. for 1 hour in a tube furnace under an inert gas (Ar) atmosphere and then heat treated at 550 ° C. for 5-7 hours in an oxygen or air atmosphere, and at room temperature in an oxygen or air atmosphere. By removing the carbon template portion in the same manner as described above to prepare a ceramic nanocapsule having a mesoporous shell and gold nanoparticles inside the hollow. Data on Au @ silica capsules prepared according to this example are shown in Table 3 at each step. Electron micrographs of silica nanocapsules with gold (Au) nanoparticles at the center treated with inert gas (nitrogen or argon) are shown in FIGS. 4B (TEM photo) and FIG. 5 (SEM photo).

template Core size (nm) Shell thickness (nm) Size of mesopores in HCMS shell (nm) Au @ SiO ₂ SCMS 200 30 2.9 Au @ Carbon Nano Capsule 195 24 4.3 Au @ SiO ₂ Capsules (Nitrogen or Argon) 190 24 2.6 Au @ SiO ₂ Capsules (Oxygen or Air) 152 18 1.7

In this result, it can be seen that the treatment of oxygen or air directly from room temperature causes a large shrinkage, which greatly reduces the size of macropores and mesopores in the outer surface of the prepared silica nanocapsules.

In addition to the silica precursor, the use of ceramic precursors of other compositions, such as TiO ₂ , SnO ₂ , ZnO ₂ , ZrO ₂ , Al ₂ O ₃ , shows similar results as in the preparation of silica nanocapsules.

Therefore, as described above, the carbon nanocapsule, carbon nanocapsule containing the metal nanoparticles in the hollow interior of the new form of the porous structure consisting of a mesoporous shell of uniform size while the center has a constant size macropore Capsules and ceramic nanocapsule structures can be synthesized using various precursors. In particular, by using various ceramic precursors, ceramic nanocapsules having various compositions can be obtained. In addition, as the active metal included in the hollow interior, instead of gold, platinum, silver, cobalt, and other metal nanoparticles can be synthesized in a variety of structures inside the hollow. In particular, it is possible to transfer mass between the inside and outside of the capsule, and also due to the chemical and physical properties of the metal nanoparticles in the capsule, catalysts, separators, hydrogen storage and release, drug storage and delivery materials, adsorbents, membranes and membrane fillers It can be effectively used for sensors, sensors, and the like.

As described above, the present invention is synthesized using Au @ SCMS silica nanoparticles as a template, while having a macropore of a certain size in the center and the outer sphere is a spherical gold nanoparticles inside the hollow consisting of a uniform mesoporous shell Shows the synthesis of polymer, carbon and ceramic nanocapsule structures. In particular, it is possible to easily control the size of the macropore at the center, the thickness of the outer and mesoporous and the size of the central metal nanoparticles in a relatively simple process. In addition, various precursors can be used to synthesize various types of capsules with new composition and structure, and they can be widely applied to various applications such as catalysts, separators, desorbents, water purifiers, adsorbents, membrane materials, sensors and storage agents. have.

Figure 1 schematically shows a manufacturing process of a polymer / carbon / ceramic HCMS capsule structure containing a metal nanoparticle in the hollow interior according to the present invention. However, the manufacturing process of the ceramic HCMS capsule structure was represented about the manufacturing process of a silica HCMS capsule structure typically.

FIG. 2 is a transmission electron microscope (TEM) photograph of gold (Au) nanoparticles prepared in the present invention and particles coated with silica on a surface of gold nanoparticles.

FIG. 3 is a spherical silica (Au @ SiO ₂ ) particle (FIG. 3A) and a spherical Au @ SiO ₂ center and a mesoporous outer shell coated with silica and grown on the surface of the gold (Au) nanoparticles synthesized for use as a template. TEM image of the constructed uniformly sized silica particles (Au @ SCMS SiO ₂ ) (FIG. 3B).

Figure 4 is a TEM image of carbon nanocapsules (Fig. 4a) and ceramic nanocapsules (Fig. 4b) having a constant size of nanopores with gold nanoparticles inside the hollow composite synthesized according to the present invention. The macropore size of the carbon nanocapsules of Figure 4a is about 195 nm, the size of the outer mesopore is about 4.3 nm. On the other hand, the macropore size of the ceramic nanocapsules of Figure 4b is about 190 nm, the size of the outer mesopore is about 2.6 nm.

FIG. 5 is a scanning electron microscope (SEM) photograph of a spherical silica capsule structure in which gold nanoparticles are included in a hollow interior having a constant sized mesoporous outline synthesized according to the present invention.

Claims (8)

A metal inside the hollow, characterized in that it comprises metal nanoparticles having a diameter of 0.5 to 50 nm in a hollow having a diameter of 30 to 2000 nm with a thickness of 10 to 200 nm and surrounded by an evenly distributed outer shell with a diameter of 2 to 8 nm. Hollow double nanocapsule structure comprising nanoparticles and having a mesoporous outer shell. The hollow double nanocapsule structure of claim 1, wherein the metal nanoparticles are gold, platinum, silver, or cobalt. The hollow double nanocapsule structure of claim 1, wherein the outer shell is made of a polymer, carbon, or ceramic. According to claim 3, wherein the polymer is divinylbenzene (DVB: divinylbenzene), acrylonitrile (acrylonitrile), phenolic resin (phenolic resin), vinyl chloride, vinyl acetate, styrene, methacrylate, methyl methacrylate, ethylene Glycol dimethacrylate, furfuryl alcohol, resorcinol-formaldehyde (RF), urea, melamine, sugar and a compound represented by the general formula CH ₂ = CRR ', wherein R and R 'is an alkyl group or an aryl group) or a mesophase pitch (hesophase pitch), characterized in that the hollow double nanocapsule structure comprising a metal nanoparticle in the hollow interior and having a mesoporous shell. The hollow _double of claim 3, wherein the ceramic is SiO ₂ , TiO ₂ , SnO ₂ , ZnO ₂ , ZrO _2, or Al ₂ O ₃ . Nano capsule structure. A) synthesizing metal nanoparticles; B) coating silica on the surface of the synthesized metal nanoparticles to synthesize silica particles (M @ silica) containing metal nanoparticles therein; C) synthesizing SCMS silica particles by forming a mesoporous shell on the outside of the M @ silica synthesized above; D) injecting a polymer precursor and a polymerization initiator into the mesopores of the outer shell of the SCMS silica particles and proceeding the polymerization reaction to synthesize a polymer-M @ silica template complex; And E) removing the silica from the polymer-M @ silica template composite to produce a hollow core with mesoporous shell (HCMS) polymer nanocapsule structure comprising a metal nanoparticle in the hollow interior, A method for producing a hollow double nanocapsule structure comprising a metal nanoparticle in a hollow interior according to any one of claims 1 to 6 which is a polymer and has a mesoporous outer shell. A) synthesizing metal nanoparticles; B) coating silica on the surface of the synthesized metal nanoparticles to synthesize silica particles (M @ silica) containing metal nanoparticles therein; C) synthesizing SCMS silica particles by forming a mesoporous shell on the outside of the M @ silica synthesized above; D) injecting a polymer precursor and a polymerization initiator into the mesopores of the outer shell of the SCMS silica particles and proceeding the polymerization reaction to synthesize a polymer-M @ silica template complex; E) carbonizing the polymer-M @ silica template composite to synthesize a carbon-M @ silica template composite; And F) removing the silica from the carbon-M @ silica template composite synthesized above, and preparing the HCMS carbon nanocapsule structure including the metal nanoparticles in the hollow interior, wherein the outer shell is carbon. A method of manufacturing a hollow double nanocapsule structure comprising a metal nanoparticle in a hollow interior according to claim 6 and having a mesoporous outer shell. A) synthesizing metal nanoparticles; B) coating silica on the surface of the synthesized metal nanoparticles to synthesize silica particles (M @ silica) containing metal nanoparticles therein; C) synthesizing SCMS silica particles by forming a mesoporous shell on the outside of the M @ silica synthesized above; D) injecting a polymer precursor and a polymerization initiator into the mesopores of the outer shell of the SCMS silica particles and proceeding the polymerization reaction to synthesize a polymer-M @ silica template complex; E) carbonizing the polymer-M @ silica template composite to synthesize a carbon-M @ silica template composite; F) preparing a HCMS carbon nanocapsule structure including metal nanoparticles in the hollow by removing silica from the carbon-M @ silica template composite synthesized above; G) injecting a ceramic precursor into the mesopores of the outer surface of the synthesized carbon-M @ silica template composite and converting the ceramic precursor into a ceramic to synthesize the ceramic-M @ carbon composite; And H) removing the carbon through the sintering reaction to produce a HCMS ceramic nanocapsule structure comprising the metal nanoparticles in the hollow interior, characterized in that the outer shell is a ceramic of any one of claims 1 to 6. Method for producing a hollow double nanocapsule structure comprising a metal nanoparticles in the hollow and having a mesoporous outer shell.