CN103476524B - Manufacture the method for the metal nanoparticle with nucleocapsid structure with oxidative stability - Google Patents

Abstract

One aspect of the present invention relates to a method of manufacturing metal nanoparticles having a core-shell structure with good oxidation stability, wherein the method comprises the steps of: heating and stirring the core metal precursor solution; mixing with the heated and stirred nuclear metal precursor solution, and heating and stirring the mixed metal precursor solution; and irradiating the heated and stirred metal precursor solution with radiation. Thus, since the yield can be maximized by a simple and environmentally friendly process that does not use a chemical reducing agent, a process for removing the added reducing agent is not required, and since the post-heat treatment of the particles is not performed, the manufacturing The process is simple and highly economical.

Description

Method for producing metal nanoparticles with core-shell structure with oxidation stability

technical field

The present invention relates to a method for producing metal nanoparticles having a core-shell structure with excellent oxidation stability.

Background technique

There are various methods of producing metal nanoparticles with a core-shell structure. A method of producing metal nanoparticles by using a chemical reduction method or by physically separating bulk metal particles is mainly used.

To produce metal nanoparticles, a chemical reduction method using a chemical reducing agent or an electroless plating method in which metal nanoparticles are synthesized by changing the reduction potential of a metal precursor solution may be used. Here, the chemical reducing agent may include hydrazine, alcohol, surfactant, citric acid, and the like. Metal nanoparticles having a core-shell structure and/or metal nanoparticles having an alloy structure may be synthesized by reducing metals from metal ions or organometallic compounds using the above chemical reducing agents. This chemical synthesis of metal nanoparticles using a chemical reduction method makes it possible to manufacture uniform metal nanoparticles; however, the aggregation of metal nanoparticles tends to be extremely strong, thus requiring a post-heat treatment. In addition, since a large amount of reducing agent harmful to the human body is used, a process of treating the remaining reducing agent after the reaction is also required.

In addition to the chemical reduction method, the synthesis of metal nanoparticles may also include: a method of synthesizing metal nanoparticles under high temperature, high pressure, or a specific atmosphere achieved by controlling the synthesis atmosphere; and physical separation of bulk metal particles using physical force Methods. These methods can facilitate the production of nanoparticles of various metal components; however, impurities can be mixed and expensive equipment can be required.

In order to solve these problems, the metal precursor solution can be irradiated with rays, and the free radicals generated in the solution can be used to reduce the metal precursor.

However, as a result of experiments, irradiating rays is not enough to ensure the oxidation stability of metal nanoparticles having a core-shell structure. Therefore, there is an urgent need to study new schemes for improving the oxidation stability of metal nanoparticles in addition to producing metal nanoparticles using radiation irradiation.

Contents of the invention

technical problem

Aspects of the present invention provide a method of manufacturing metal nanoparticles having a core-shell structure having excellent oxidation stability by irradiating radiation without using a chemical reducing agent.

Technical solutions

According to an aspect of the present invention, there is provided a method of producing metal nanoparticles having a core-shell structure having excellent oxidation stability, the method comprising: heating and stirring a core metal precursor solution; The precursor solution is mixed with the shell metal precursor solution, and the mixed metal precursor solution is heated and stirred; and the heated and stirred metal precursor solution is irradiated with rays.

The core metal precursor solution may be heated and stirred at 30° C.˜300° C. for 10˜120 minutes.

The mixed metal precursor solution may be heated and stirred at 30° C.˜300° C. for 10˜120 minutes.

The radiation may contain one or more radiations selected from electron beam radiation, X-rays, and γ-rays, and the radiation may have an absorbed dose of 10 kGy to 500 kGy.

The core metal precursor solution may comprise ions of one or more metals selected from the group consisting of gold, silver, copper, platinum, nickel, zinc, palladium, rhodium, ruthenium, iridium, osmium, tungsten, tantalum, titanium, Aluminum, Cobalt and Iron.

The core metal precursor solution may contain capping molecules.

The modified molecule may comprise one or more compounds selected from the group consisting of compounds having a thiol group, compounds having a carboxyl group, and compounds having an amine group.

The modified molecule may comprise one or more compounds having amine groups selected from the group consisting of propylamine, butylamine, octylamine, decylamine, dodecylamine, hexadecylamine and oleylamine.

The shell metal precursor solution may contain ions of one or more metals selected from the group consisting of gold, silver, copper, platinum, nickel, zinc, palladium, rhodium, ruthenium, iridium, osmium, tungsten, tantalum, titanium, Aluminum, Cobalt and Iron.

The metal contained in the shell metal precursor solution may have a lower degree of oxidation than the metal contained in the core metal precursor solution.

Beneficial effect

According to aspects of the present invention, there is provided a method of manufacturing metal nanoparticles having a core-shell structure, which can increase the manufacturing yield and reduce the manufacturing cost due to a simplified manufacturing process that does not An environmentally friendly process using a chemical reducing agent, which does not require a process for removing residual reducing agent and post-heat treatment.

In particular, since the metal precursor solution is irradiated with rays after the heat treatment, the oxidation stability of the metal nanoparticles can be further improved.

Description of drawings

Figure 1 shows an image of copper-silver core-shell nanoparticles of a conceptual embodiment of the invention analyzed by high resolution transmission electron microscopy (HR-TEM);

Figure 2 shows an elemental distribution (mapping) image of copper-silver core-shell nanoparticles according to a conceptual embodiment of the invention;

Fig. 3 shows the spectroscopic analysis results of the energy dispersive spectroscopy (EDS) of the copper-silver core-shell nanoparticles of the conceptual embodiment of the present invention;

Figures 4 to 7 show the elemental distribution analysis results of copper-silver core-shell nanoparticles of a conceptual embodiment of the present invention using a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM);

Figure 8 shows the results of a 70-week X-ray diffraction (XRD) analysis of copper-silver core-shell nanoparticles according to a conceptual embodiment of the present invention;

Fig. 9 shows the element distribution image of the copper-silver nanoparticles of Comparative Example 1;

Figure 10 shows the EDS spectral analysis result of the copper-silver nanoparticles of Comparative Example 1;

Figure 11 shows an image of the copper-silver nanoparticles of Comparative Example 2 analyzed by HR-TEM; and

FIG. 12 shows the results of EDS spectral analysis of the copper-silver nanoparticles of Comparative Example 2. FIG.

detailed description

According to an embodiment of the inventive concept, the method of manufacturing metal nanoparticles having a core-shell structure having excellent oxidation stability may include: heating and stirring a core metal precursor solution; mixing the heated and stirred core metal precursor solution with The shell metal precursor solutions are mixed, and the mixed metal precursor solutions are heated and stirred; and the heated and stirred metal precursor solutions are irradiated with rays.

First, according to an embodiment of the present inventive concept, metal nanoparticles having a core-shell structure may be manufactured by irradiating a metal precursor solution with rays and reducing the precursor. However, as a result of experiments, this radiation irradiation method can provide metal nanoparticles without chemical additives or environmental problems, but the method is insufficient to ensure the oxidation stability of metal nanoparticles.

Therefore, in order to ensure the oxidation stability of the metal nanoparticles, the core metal precursor solution may be heated and stirred in advance, and then the core metal precursor solution and the shell metal precursor solution are mixed with each other and the mixture is heated and stirred again.

In the case where the core metal precursor solution and the shell metal precursor solution are heated and stirred after being mixed with each other, the metal contained in the core metal precursor solution is alloyed with the metal contained in the shell metal precursor solution, As a result, metal nanoparticles with a core-shell structure cannot be produced.

In the case where heat treatment is not performed, the nanoparticles in the shell have pores such that they can come into contact with air through the pores, whereby the pores would be easily oxidized. When the metal precursor solution is heat-treated to increase its temperature to the melting point of the shell, the nanoparticles in the shell melt and completely encapsulate the pores, thereby completely preventing the pores, which would be easily oxidized, from contact with air, thereby improving oxidation stability.

Therefore, when the metal precursor solution is heated and stirred and then irradiated with radiation, the metal nanoparticles having a core-shell structure can achieve higher oxidation stability.

When heating and stirring the core metal precursor solution, the heating temperature may be controlled to be 30°C to 300°C. In the case where the heating temperature is lower than 30° C., the effect of securing oxidation stability by heat treatment may not be significant. In the case where the heating temperature exceeds 300° C., alloying occurs, resulting in a decrease in production yield.

In order to fabricate uniform core-shell nanoparticles, smooth agitation of the core metal precursor solution is required. In order to enable this, it is necessary to perform the stirring process for a predetermined period of time. The stirring time can be controlled to 10 to 120 minutes. In the case where the stirring time is shorter than 10 minutes, it may be difficult to obtain sufficient uniformity. In the case where the stirring time exceeds 120 minutes, the production yield is adversely affected.

The heated and stirred core metal precursor solution can then be mixed with the shell metal precursor solution. Thereafter, the mixture of the core metal precursor solution and the shell metal precursor solution may be heated and stirred again. Here, when the temperature of the mixture is raised to the melting point of the shell, the nanoparticles in the shell melt and completely encapsulate the core, thereby completely preventing the core, which would be easily oxidized, from contact with air, thereby improving oxidation stability.

When the mixture is heated and stirred after the core metal precursor solution and the shell metal precursor solution are mixed with each other, the heating temperature can be controlled to be 30°C to 300°C. In the case where the heating temperature is lower than 30° C., the effect of securing oxidation stability by heat treatment may not be significant. In the case where the heating temperature exceeds 300° C., alloying occurs, resulting in a decrease in production yield.

To fabricate uniform core-shell nanoparticles, smooth agitation of the mixed metal precursor solution is required. In order to enable this, it is necessary to perform the stirring process for a predetermined period of time. The stirring time can be controlled to 10 to 120 minutes. In the case where the stirring time is shorter than 10 minutes, it may be difficult to obtain sufficient uniformity. In the case where the stirring time exceeds 120 minutes, the production yield is adversely affected.

Thereafter, the heated and stirred metal precursor solution may be irradiated with radiation. Here, the radiation may contain one or more radiations selected from electron beam radiation, X-rays, and gamma rays. In addition, radiation can be irradiated by controlling the absorbed dose of radiation to 10 kGy to 500 kGy. Irradiation with radiation is intended to reduce the precursor solution. In cases where the absorbed dose is less than 10 kGy, the reduction process may not be sufficient to properly form metal nanoparticles. In the case where the absorbed dose exceeds 500 kGy, the size of manufactured nanoparticles may be increased and the core and shell may be formed separately, thereby deteriorating the properties of the nanoparticles. Therefore, the energy of the radiation and its absorbed dose can be properly controlled taking into account the size of the nanoparticles.

Here, the core metal precursor solution may contain ions of one or more metals selected from the group consisting of gold, silver, copper, platinum, nickel, zinc, palladium, rhodium, ruthenium, iridium, osmium, tungsten, tantalum, titanium , aluminum, cobalt and iron.

Additionally, the shell metal precursor solution may contain ions of one or more metals selected from the group consisting of gold, silver, copper, platinum, nickel, zinc, palladium, rhodium, ruthenium, iridium, osmium, tungsten, tantalum, titanium, Aluminum, Cobalt and Iron.

The metal contained in the shell metal precursor solution may have a lower degree of oxidation than the metal contained in the core metal precursor solution. Compared with the metal contained in the core metal precursor solution, the metal contained in the shell metal precursor solution that forms the shell for coating the core can be relatively difficult to be oxidized, so that the oxidation of the core metal or the metal nanoparticles can be prevented. The aggregation between them can further ensure the stability of the metal nanoparticles.

In addition, the core metal precursor solution may further include modifying molecules. In the case where modifying molecules are mixed with the core metal precursor solution to encapsulate the nanoparticles, the particles can be grown more stably at the nanometer scale compared to the case where the core metal precursor solution is only heat-treated to form the core, which It is beneficial for the stability of metal nanoparticles.

Here, the modification molecule may contain one or more compounds selected from the group consisting of compounds having a thiol group, compounds having a carboxyl group, and compounds having an amine group.

The modifying molecule may comprise at least one selected from the group consisting of propylamine, butylamine, octylamine, decylamine, dodecylamine, hexadecylamine, and oleylamine. A compound having an amine group can be used as the most suitable modifying molecule. In particular, dodecylamine, hexadecylamine, and oleylamine may be preferably used for forming uniform particles in view of being effective in promoting the formation of uniform particles when the length of the carbon ring is increased.

Hereinafter, embodiments of the inventive concept will be described in detail with reference to the accompanying drawings. However, inventive concepts may be illustrated in many different forms and should not be construed as limited to the specific embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art.

(invention example)

Copper acetylacetonate (C ₅ H ₇ CuO ₂ ) was used as the core metal precursor solution, and the core metal precursor solution was heated to 100° C. and stirred for 30 minutes. Then, a silver precursor solution as a shell metal precursor solution was mixed therewith, and the mixture was heated to 50° C. and stirred for 1 hour. Thereafter, the mixture was irradiated with an electron beam under conditions of 0.1 MeV to 20 MeV, 0.001 mA to 50 mA, and 10 kGy to 500 kGy, thereby manufacturing copper-silver core-shell nanoparticles.

Figures 1A and 1B show images of fabricated copper-silver core-shell nanoparticles analyzed by high-resolution transmission electron microscopy (HR-TEM). As indicated, the surface of copper nanoparticles with a particle size of 150 nm ± 50 nm was encapsulated to a thickness of 60 nm ± 10 nm with silver nanoparticles.

In addition, FIGS. 2A to 2E show elemental distribution images of fabricated copper-silver core-shell nanoparticles. As shown, the core and shell do not form an alloy; rather, the copper nanoparticles as the core are located inside and the silver nanoparticles as the shell are arranged in such a way as to encapsulate the copper nanoparticles, thereby forming a core-shell structure.

In addition, Fig. 3 shows the spectroscopic analysis results of energy dispersive spectroscopy (EDS) of the fabricated copper-silver core-shell nanoparticles. As shown, the fabricated copper and silver nanoparticles were not oxidized, thus exhibiting excellent oxidation stability.

In addition, FIGS. 4 to 7 show the element distribution analysis results of the fabricated copper-silver core-shell nanoparticles by using a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM). As shown, the silver nanoparticles completely encapsulated the copper nanoparticles, thereby forming uniform core-shell nanoparticles.

Finally, Figure 8 shows the results of X-ray diffraction (XRD) analysis of the fabricated copper-silver core-shell nanoparticles. As a result of XRD analysis, the fabricated copper-silver nanoparticles were identified as unoxidized copper-silver nanoparticles having a face-centered cubic (FCC) lattice structure, and no oxidation peak was generated during the measurement time of 70 weeks. The unoxidized copper-silver nanoparticles achieve excellent oxidation stability by irradiating the precursor solution with heat treatment.

(comparative example 1)

Copper acetylacetonate (C ₅ H ₇ CuO ₂ ) was used as the core metal precursor solution, and the core metal precursor solution was heated to 250° C. and stirred for 30 minutes. Then, a silver precursor solution as a shell metal precursor solution was mixed therewith, and the mixture was heated to 25° C. and stirred for 1 hour. Thereafter, the mixture is irradiated with an electron beam under conditions of 0.1 MeV to 20 MeV, 0.001 mA to 50 mA, and 10 kGy to 500 kGy.

9A to 9E show elemental distribution images of fabricated copper-silver nanoparticles. As shown, the precise shape of the copper nanoparticles was not clearly identified. That is, no core-shell structure was formed.

In addition, FIG. 10 shows the results of EDS spectral analysis of the produced copper-silver nanoparticles. Figure 10 supports the copper shapes shown in Figure 9.

(comparative example 2)

Copper acetylacetonate (C ₅ H ₇ CuO ₂ ) was used as the core metal precursor solution, and the core metal precursor solution was heated to 350° C. and stirred for 30 minutes. Then, a silver precursor solution as a shell metal precursor solution was mixed therewith, and the mixture was heated to 350° C. and stirred for 1 hour. Thereafter, the mixture is irradiated with an electron beam under conditions of 0.1 MeV to 20 MeV, 0.001 mA to 50 mA, and 10 kGy to 500 kGy.

Figure 11 shows images of fabricated copper-silver nanoparticles analyzed by HR-TEM. Figure 11 shows copper-silver nanoparticles with an alloy structure other than a core-shell structure.

In addition, FIG. 12 shows the results of EDS spectral analysis of the produced copper-silver nanoparticles. Figure 12 supports the shape of the copper-silver alloy shown in Figure 11.

Claims (10)

1. manufacture has a method for the metal nanoparticle with nucleocapsid structure of oxidative stability, and described method comprises:

Heat and stir core metal precursor solutions;

By through heating and the core metal precursor solutions stirred mix with shell metal precursor solutions, and heat and stir through mixing metal precursor solutions; And

Utilize ray to through heating and the metal precursor solutions stirred irradiate.

2. method according to claim 1, wherein heats described core metal precursor solutions at 30 DEG C��300 DEG C and stirs 10��120 minutes.

3. method according to claim 1, wherein heats the described metal precursor solutions through mixing at 30 DEG C��300 DEG C and stirs 10��120 minutes.

4. method according to claim 1, wherein said ray comprises one or more rays being selected from electron beam ray, X-ray and gamma-rays, and

Described ray has the absorption dose of 10kGy��500kGy.

5. method according to claim 1, wherein said core metal precursor solutions comprises the ion being selected from one or more following metals: gold and silver, copper, platinum, nickel, zinc, palladium, rhodium, ruthenium, iridium, osmium, tungsten, tantalum, titanium, aluminium, cobalt and iron.

6. method according to claim 1, wherein said core metal precursor solutions comprises decorating molecule.

7. method according to claim 6, wherein said decorating molecule comprises and is selected from one or more following compounds: the compound with thiol, the compound with carboxyl and have the compound of amido.

8. method according to claim 6, wherein said decorating molecule comprises and is selected from one or more following compounds with amido: propylamine, butylamine, octylame, decyl amine, n-Laurylamine, cetylamine and oil amine.

9. method according to claim 1, wherein said shell metal precursor solutions comprises the ion being selected from one or more following metals: gold and silver, copper, platinum, nickel, zinc, palladium, rhodium, ruthenium, iridium, osmium, tungsten, tantalum, titanium, aluminium, cobalt and iron.

10. method according to claim 1, the degree of oxidation of the metal being wherein included in described shell metal precursor solutions is lower than the degree of oxidation of the metal being included in described core metal precursor solutions.