WO2016175409A1 - Method for preparing metal/ceramic composite nanostructure, metal/ceramic composite nanostructure prepared by method, and catalyst comprising same - Google Patents

Abstract

The present invention relates to a metal/ceramic composite nanostructure and, to a method for preparing a metal/ceramic composite nanostructure, comprising: an interfacially-active metal nanoparticle solution preparation step of mixing a colloid solution of metal nanoparticles coated with a surfactant and a surfactant aqueous solution in which the surfactant is dissolved in water; a metal nanoparticle-chelate mixture solution preparation step of mixing the interfacially-active metal nanoparticle solution and a chelate solution; a metal nanoparticle-chelate-rare earth metal ion mixture solution preparation step of mixing the metal nanoparticle-chelate mixture solution with a rare earth metal ion solution and an oxidizing agent; and a maturation step of maturing the metal nanoparticle-chelate-rare earth metal ion mixture solution. A rare earth metal oxide film having a uniform thickness can be formed as a shell since the nanoparticles surrounded by the surfactant are positively charged and the chelate-rare earth ion composite is negatively charged, thereby inducing a reaction therebetween by electrostatic force, and the thickness of the shell can be readily controlled at the nanoscale level by controlling the amount of the chelate solution and the rare earth ions.

Description

Method for producing metal / ceramic composite nanostructure, metal / ceramic composite nanostructure manufactured by the method, and catalyst comprising the same

The present invention relates to a metal / ceramic composite nanostructure, and more particularly, to preparing a metal nanoparticle solution prepared by mixing a metal nanoparticle colloid solution coated with a surfactant and a surfactant solution in which the surfactant is dissolved in water. Preparing a metal nanoparticle-chelate mixed solution in which a chelate solution is mixed with the surface active metal nanoparticle solution; and mixing a metal nanoparticle-chelate-rare earth metal ion in which a rare earth metal ion solution is mixed with the metal nanoparticle-chelate mixed solution The present invention relates to a method for preparing a metal / ceramic composite nanostructure comprising a step of preparing a solution and a step of maturing the metal nanoparticle-chelate-rare earth metal ion mixed solution.

Core-shell nanoparticles are composed of a structure surrounding a material forming a shell around the core material existing in the center. Core-shell nanoparticles having such a structure are distinguished from those in which two or more materials are simply mixed or present in an alloy, and at least 2 depending on the characteristics of the materials used for each core and shell. It is possible to provide a composite material nanomaterial exhibiting more than two characteristics. Research and development of core-shell structured nanoparticles by various combinations, including metal-metal, metal-ceramic, metal-organic, organic-organic structures, has been carried out. Due to the combination of features such as resistance, acid resistance, and abrasion resistance, it has been shown to be highly applicable to various fields.

Nanoparticles with a core-shell structure may be classified according to the type of materials used in the core and shell, or according to characteristics such as magnetic properties, fluorescence, and photocatalytic properties, or may be classified according to an application field. have.

Conventionally used methods for preparing the core-shell structured nanoparticles are prepared by 1) simultaneously injecting the precursors forming the core and the shell onto a single solvent, and then performing oxidation / reduction reactions between the precursors, or 2) reducing agents. After the core particles were first produced, the precursor was formed to form the shell layer, and the shell layer was formed around the core through oxidation or reduction.

The problem in the above method is that the precursor of the material to form the core and the precursor of the material forming the shell at the same time, there is a disadvantage that it is not easy to distinguish the core and the shell in the core-shell nanostructure as the final product. In addition, when synthesizing the core-shell structure by first preparing the core particles and then adding a salt solution of diluted metal, it is difficult to finely control the formation of agglomerates and the formation of the shell. The disadvantage is that it is not easy.

In addition, the type of each material used in the core and the shell is still limited, a lot of research has been done on only a few kinds.

[Preceding technical literature]

[Patent Documents]

United States Patent Application Publication No. 2011-0250122

Korean Patent Publication No. 2011-0039733

In the present invention, in preparing a metal / ceramic composite nanostructure having a core-shell structure, a surfactant metal nanoparticle solution in which a metal nanoparticle colloidal solution coated with a surfactant and a surfactant aqueous solution in which the surfactant is dissolved in water are mixed. A core having a rare earth oxide film, which has been previously limited in synthesis due to the electrostatic reaction of negatively charged chelate-rare earth complexes with each other in the surface-charged surfactant metal nanoparticles and the metal nanoparticle-chelate-rare earth metal ion mixed solution Provided is a method for preparing a metal / ceramic composite nanostructure having a shell structure.

In addition, the present invention provides a metal / ceramic composite nanostructure having a core-shell structure that is thermally stable due to the formation of the rare earth oxide layer.

In addition, due to the electrostatic reaction, a uniform core-shell metal / ceramic composite nanostructure can be manufactured, and can be manufactured by adjusting the shell thickness of the core-shell metal / ceramic composite nanostructure. Provide a method.

The present invention is to solve the above problems, the manufacturing method of the surface active metal nanoparticles mixed with a metal nanoparticle colloidal solution coated with a surfactant and a surfactant aqueous solution dissolved in water, the surface active metal nanoparticles A metal nanoparticle-chelate mixed solution preparation step of mixing a chelate solution into a solution, a metal nanoparticle-chelate-rare earth metal ion mixed solution preparation step of mixing a rare earth metal ion solution with the metal nanoparticle-chelate mixed solution, and the metal It provides a method for producing a metal / ceramic composite nanostructure comprising a aging step of aging the nanoparticle-chelate-rare earth metal ion mixed solution.

In the aging step, the metal nanoparticle-chelate-rare earth metal ion mixed solution is preferably maintained at 60 ° C. to 90 ° C. for 1 hour to 24 hours.

It is preferred that the calcination step of separating and heat-treating the metal / ceramic composite nanostructures generated after the aging step.

The metal nanoparticles are selected from the group consisting of gold (Au), silver (Ag), cobalt (Co), copper (Cu), iron (Fe), nickel (Ni), palladium (Pd), and platinum (Pt). It is preferable that it is 1 or more types.

It is preferable that the particle diameter of the metal nanoparticles is 2nm to 200nm.

The surfactant is a group consisting of Tetradecyl Trimethyl Ammonium Bromide (TTAB), Dodecyl Trimethyl Ammonium Bromide (DTAB), and Cetyl Trimethyl Ammonium Bromide (CTAB) It is preferable that it is 1 or more types chosen from.

It is preferable that the said surface active metal nanoparticle solution is 0.1-1 volume ratio, the chelating solution is 1-10 volume ratio, and the rare earth metal ion solution is 0.1-1 volume ratio with respect to 40 volume ratio of water.

The chelating agent is ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), (1,2-cyclohexylene dinitrilo) tetraacetic acid ((1,2-cyclohexylene dinitrilo) tetraacetic acid , CyDTA), diethylene triamine pentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA-OH), glycol-bis (2-aminoethylether) -N, N, N ' Glycol-bis (2-aminoethylether) -N, N, N ', N'-tetraacetic acid (GEDTA), triethylenetetraminehexaacetic acid (TTHA), dihydroxyethylglycine (Dihydroxy Ethyl Glycine, DHEG), iminodiacetate (IDA), metal-Ethylenediaminetetraacetic acid (Me-EDTA), Hydroxy Imminodiacetic acid (HIDA), and EDTPO Preferably at least one member selected from the group consisting of is preferred.

The chelating solution is preferably prepared by mixing an oxidizing agent and a chelating agent in water.

The oxidizing agent is an ammonium salt, preferably at least one selected from the group consisting of ammonium hydroxide (NH ₄ OH), urea (UREA), and hexamethylenetetramine (HMTA).

The rare earth metal ion solution is ionized rare earth metal, and the rare earth metal is cerium (Ce), samarium (Sm), gadolindium (Gd), lanthanum (La), praseodymium (Pr), yttrium (Y), neodymium At least one selected from the group consisting of (Nd), europium (Eu), erbium (Er), dysprosium (Dy), holmium (Ho), tolium (Tm), ytterbium (Yb), and ruthenium (Lu) desirable.

In the preparing of the metal nanoparticle-chelate-rare earth metal ion mixed solution, the rare earth metal ion solution is preferably prepared by diluting the rare earth metal ion precursor in water.

On the other hand, the present invention provides a metal / ceramic nanostructure prepared by the above method.

The metal / ceramic nanostructures preferably have a rare earth metal oxide film of 1 nm to 200 nm.

The present invention also provides a catalyst comprising a metal / ceramic nanostructure prepared by the above method.

The metal nanoparticles surrounded by the surfactant are sequentially mixed with a chelating solution and a rare earth metal ion solution in a surfactant metal nanoparticle solution mixed with a metal nanoparticle coated with a surfactant and an aqueous solution of a surfactant dissolved in water. Has a positive charge, and the complex of the chelate and the rare earth metal ions has a negative charge, so that the reaction is induced by an electrostatic force with each other, so that the rare earth metal oxide film can be formed in a uniform thickness as a shell.

In addition, the method of manufacturing the metal / ceramic composite nanostructure of the present invention can easily control the thickness of the shell in nanoscale by adjusting the amount of the chelate solution and rare earth metal ions. The metal / ceramic composite nanostructure exhibits excellent stability at high temperature by the rare earth metal oxide film and has excellent dispersibility because physical dispersion of metal nanoparticles is achieved by the rare earth metal oxide film.

1 is a flow chart showing a manufacturing step according to the present invention.

2 is a TEM photograph of a metal / ceramic composite nanostructure prepared according to the present invention.

3 is a TEM photograph after heat treatment of the platinum (core) -cerium oxide film (shell) prepared according to the present invention at 300 ° C and 400 ° C for 2 hours, respectively.

4 is a TEM photograph after heat treatment of a platinum (core) -cerium oxide film (shell) prepared according to the present invention at 300 ° C. for 5 hours.

5 is a TEM photograph after heat treatment of a platinum (core) -cerium oxide film (shell) prepared according to the present invention at 700 ° C. for 3 hours.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. In the drawings, the thickness or size of each layer may be exaggerated for convenience and clarity of description and may differ from the thickness or size of the actual layer.

The terms top, bottom, top, bottom, or top, bottom, etc. are used to distinguish relative positions in the component. For example, in the case of naming the upper part on the drawing as the upper part and the lower part on the drawing for convenience, the upper part may be called the lower part and the lower part may be named the upper part without departing from the scope of the present invention. .

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, a method of preparing a metal / ceramic composite nanostructure according to an embodiment of the present invention, a metal / ceramic composite nanostructure prepared according to the present invention, and a catalyst including the same will be described in detail with reference to the accompanying drawings.

Meanwhile, FIG. 1 is a flowchart illustrating a manufacturing step according to the present invention, and FIG. 2 is a TEM photograph of a metal / ceramic composite nanostructure manufactured according to the present invention. 3 is a TEM photograph after heat treatment of the platinum (core) -cerium oxide film (shell) prepared according to the present invention at 300 ° C. and 400 ° C. for 2 hours, respectively, and FIG. 4 is a platinum produced according to the present invention. It is a TEM photograph after heat-processing a (core) -cerium oxide film (shell) at 300 degreeC for 5 hours. 5 is a TEM photograph of the platinum (core) -cerium oxide film (shell) prepared according to the present invention after heat treatment at 700 ° C. for 3 hours.

In the metal / ceramic composite nanostructure of the present invention, a surface active metal nanoparticle solution prepared by mixing a colloidal metal nanoparticle colloid solution coated with a surfactant and an aqueous solution of a surfactant dissolved in water, and the surface active metal nanoparticle solution Preparing a metal nanoparticle-chelate mixed solution in which a chelate solution is mixed into the metal nanoparticle, preparing a metal nanoparticle-chelate-rare earth metal ion mixed solution in which a rare earth metal ion solution is mixed with the metal nanoparticle-chelate mixed solution, and the metal nanoparticle It is prepared through a aging step of aging a particle-chelate-rare earth metal ion mixed solution.

Referring to Figure 1 as a whole look at the manufacturing method, the metal nanoparticle colloidal solution coated with the surfactant is evenly dispersed in the surfactant solution in which the surfactant is dissolved in water to the surface of the metal nanoparticles surface active metal It becomes a nanoparticle solution, and when the chelate solution is mixed with the surfactant metal nanoparticle solution, a metal nanoparticle-chelate mixed solution is prepared. In the metal nanoparticle-chelate mixed solution, the surface-activated metal nanoparticles do not react with the chelate. When the rare earth metal ion solution is mixed with the metal nanoparticle-chelate mixed solution, a metal nanoparticle-chelate-rare earth metal ion mixed solution is prepared, and the chelate and rare earth metal ion in the metal nanoparticle-chelate-rare earth metal ion mixed solution are prepared. React to form a chelate-rare earth metal ion complex. The chelate-rare earth metal ion composite and the metal nanoparticles having the interface activated are electrostatically reacted to form an intermediate of the metal / ceramic composite nanostructure, and the reaction is completed as the metal / ceramic composite nanostructure is formed through the aging step. .

The metal nanoparticles are selected from the group consisting of gold (Au), silver (Ag), cobalt (Co), copper (Cu), iron (Fe), nickel (Ni), palladium (Pd), and platinum (Pt). It may be one or more kinds. The metal nanoparticles are metals corresponding to noble metals and transition metals, and these metals are materials used as catalysts in various fields in the industry. Specifically, the metal nanoparticles are used as chemical catalysts, electrochemical catalysts, and photocatalysts.

The metal nanoparticles may be synthesized by a colloidal synthesis method, and the synthesized metal nanoparticles may include 3 x 10 ¹³ metal nanoparticles per 1 mL of water in a solution state.

The particle diameter of the metal nanoparticles may be 2nm to 200nm. If the particle diameter of the metal nanoparticles is less than 2 nm, the surface energy is rapidly increased and the reactivity is high, so that it is difficult to control the reaction with other materials later. In addition, since the particle size of the metal nanoparticles exceeds 200 nm, the particle size is too large to be dispersed in an aqueous solution, and thus it is preferable to use metal nanoparticles within the above range because there is a limit in preparing a metal oxide film later.

When the particle diameter of the metal particles is reduced to nano size, the surface energy increases, so that aggregation occurs, resulting in a problem of poor dispersibility. Therefore, in order to prevent the agglomeration of the metal nanoparticles, the surface of the metal nanoparticles is coated with a surfactant, and the coated metal nanoparticles are dispersed in a solution containing the surfactant to participate in the reaction. It can be prepared.

The surfactant may have different properties from functional groups at both ends, for example, may have different properties from each other, or may have different affinity for materials. The surfactant used in the present invention has a positive charge on one end of the functional group to form an electrostatic bond with the complex of chelate-rare earth metal ions of the metal nanoparticle-chelate-rare earth metal ion mixed solution. The surfactant allows metal nanoparticles to be stably dispersed in the reaction solution.

The surfactant is a group consisting of Tetradecyl Trimethyl Ammonium Bromide (TTAB), Dodecyl Trimethyl Ammonium Bromide (DTAB), and Cetyl Trimethyl Ammonium Bromide (CTAB) It may be one or more selected from. It may also be other cationic surfactant. The cationic surfactant may be benzoalkonium chloride, myrtalkonium chloride, cetylpyridinium chloride, cetyltrimethyl ammonium chloride, or the like.

In addition, the aqueous surfactant solution is preferably mixed at 0.005 molar concentration to 0.05 molar concentration. When the surfactant is mixed at a concentration less than 0.005 molar concentration, the aqueous surfactant solution is too dilute, which causes a problem of not being sufficiently dispersed when the metal nanoparticles are added later. In addition, when the surfactant is mixed in excess of 0.05 molar concentration and present in excess, the chelate-rare earth metal ion complex in the metal nanoparticle-chelate-rare earth metal ion mixed solution is electrostatically charged to the surfactant on the surface of the metal nanoparticle. After adsorption by attractive force, rare earth metal oxide film should be formed through the oxidation reaction of rare earth metal ions on the surface of metal nanoparticles (heterogeneous reaction). This reaction does not occur and the reaction is not performed on the surface of metal nanoparticles. The rare earth metal oxide which does not occur as a core (homogeneous reaction) metal nanoparticles is formed, so that the surfactant is preferably mixed within the above concentration range.

It is preferable that the surface-active metal nanoparticle solution mixed with the metal nanoparticle colloidal solution coated with the surfactant and the aqueous solution of the surfactant dissolved in water is 0.1 to 1% by volume relative to 40 parts by volume of water. When the surface active metal nanoparticle solution is less than 0.1 volume ratio, since the absolute amount of the metal nanoparticles is very small, a homogeneous reaction occurs at the same time as a heterogeneous reaction, so that rare earth metal oxide nanoparticles are formed together with the core-shell nanostructure, and exceed 1 volume ratio. When the reaction is carried out by a large amount of metal nanoparticles, the metal / ceramic composite nanostructure finally formed has a close distance between the metal nanoparticles, so that effective core dispersion cannot be achieved.

When the surface active metal nanoparticle solution is prepared, a metal nanoparticle-chelate mixed solution is prepared by mixing a chelate solution thereto. The chelate solution is preferably 1 to 10 parts by volume per 40 parts by volume of water. When the chelating solution is reacted at less than 1 volume ratio, the rare earth metal ions in the rare earth metal ion solution to be added later cannot be effectively trapped, so that the rare earth metal ions that do not form the chelate-rare earth metal ion complex react directly with the oxidizing agent. To form a rare-to-metal oxide nanoparticles. Thus, no metal / ceramic composite nanostructures of the core-shell structure are formed. In addition, when the chelate solution exceeds 10 parts by volume, the chelate in the chelate solution strongly binds the rare earth metal ions so that the rare earth metal ions cannot be oxidized by the oxidizing agent, and thus, the rare earth metal oxide film cannot be formed. Since the ceramic composite nanostructure is not formed, it is preferable to mix the chelating solution within the above range.

The chelating agent is ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), (1,2-cyclohexylene dinitrilo) tetraacetic acid ((1,2-cyclohexylene dinitrilo) tetraacetic acid , CyDTA), diethylene triamine pentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA-OH), glycol-bis (2-aminoethylether) -N, N, N ' Glycol-bis (2-aminoethylether) -N, N, N ', N'-tetraacetic acid (GEDTA), triethylenetetraminehexaacetic acid (TTHA), dihydroxyethylglycine (Dihydroxy Ethyl Glycine, DHEG), iminodiacetate (IDA), metal-Ethylenediaminetetraacetic acid (Me-EDTA), Hydroxy Imminodiacetic acid (HIDA), and EDTPO Group may be at least one member selected from the consisting of.

Butylenediaminetetraacetic acid (butylenediaminetetraacetic acid), (1,2-cyclohexylenedinitrilo) tetraacetic acid ((1,2-cyclohexylenedinitrilo) tetraacetic acid (CyDTA), diethylenetriaminepentaacetic acid (DETPA) , Ethylenediaminetetrapropionic acid, (hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), N, N, N ', N'-ethylenediaminetetra (methylenephosphonic) acid (N , N, N ', N'-ethylenediaminetetra (methylenephosphonic) acid, EDTMP), 1,3-diamino-2-hydroxypropane-N, N, N', N'-tetraacetic acid (1,3-diamino- 2-hydroxypropane-N, N, N ', N'-tetraacetic acid (DHPTA), methyliminodiacetic acid, propylenediaminetetraacetic acid, nitrolotriacetic acid (NTA), citric acid (citric acid), tartaric acid, Gluconic acid, saccharic acid, glyceric acid, oxalic acid, phthalic acid, maleic acid, mandelic acid, malonic acid (malonic acid), lactic acid, salicylic acid, catechol acid, calic acid, gallic acid, propyl gallate, pyrogallol, 8-hydroxy It can be selected from the group consisting of quinoline (8-hydroxyquinoline) and cysteine (cysteine), and their isomers and salts.

After preparing a metal nanoparticle-chelate mixed solution in which the chelate solution is mixed with the surface active metal nanoparticle solution, a rare earth metal ion solution is mixed with the metal nanoparticle-chelate mixed solution to prepare a metal nanoparticle-chelate-rare earth metal ion. Prepare a mixed solution.

The rare earth metal ion solution is preferably mixed in a 0.1 to 1 volume ratio relative to a 40 volume ratio of water. If the rare earth metal ion solution is less than 0.1 volume ratio, the amount of rare earth metal ions is too small to form a rare earth metal oxide film. If the rare earth metal ion solution exceeds 1 volume ratio, the rare earth metal oxide nanoparticles as well as the core-shell structured metal / ceramic composite nanostructures Is formed together, so the above range is preferable.

The rare earth metal ions are prepared by diluting the rare earth metal ion precursor in water in the metal nanoparticle-chelate-rare earth metal ion mixed solution preparation step. For example, to prepare a cerium ion solution, cerium nitrate hexahydrate (Ce (NO ₃ )) ₃ .6H ₂ O), cerium chloride (Cerium Chloride, CeCl ₃ ), cerium bromide (cerium bromide, CeBr ₃ ), cerium sulfate (Ce (SO ₄ ) ₂ , cerium sulfate) can be used.

The rare earth metal ion solution is a rare earth metal in an ionic state in water. The rare earth metal is cerium (Ce), samarium (Sm), gadolindium (Gd), lanthanum (La), praseodymium (Pr), and yttrium ( Y), neodymium (Nd), europium (Eu), erbium (Er), dysprosium (Dy), holmium (Ho), tolium (Tm), ytterbium (Yb), and ruthenium (Lu) Can be. The metal can protect the core component of the metal / ceramic composite nanostructure because the metal itself has no phase change at high temperature and has a high melting point when the oxide is formed. In addition, some rare earth metal oxides are excellent in their catalytic properties and can be used as catalysts in various fields. In addition, the type and content of the rare earth metal ions may be appropriately adjusted according to the field used.

The chelating solution is prepared by mixing an oxidizing agent and a chelating agent in water. The oxidant may be at least one selected from the group consisting of ammonium hydroxide (NH ₄ OH), urea (UREA), and hexamethylenetetramine (HMTA).

The oxidant is diluted in water to form hydroxide ions (OH ⁻ ), and the hydroxide ions react with rare earth metal ions of the chelate-rare earth metal ion complex to form a rare earth metal hydroxide to finally form a rare earth metal oxide film. .

After preparing the metal nanoparticle-chelate-rare earth metal ion mixed solution, a aging step of allowing the reaction to proceed is necessary. The aging step maintains the metal nanoparticle-chelate-rare earth metal ion mixed solution at 60 ° C. to 90 ° C. for 1 hour to 24 hours. When the metal nanoparticle-chelate-rare earth metal ion mixed solution is left below 60 ° C., the reaction does not proceed due to insufficient energy supply, and thus, the metal / ceramic composite nanostructure of the core-shell structure is not generated. When the aging exceeds 90 ° C, the reaction rate is too fast, which makes it difficult to control the thickness of the rare earth metal oxide film, and when it proceeds above 100 ° C, water boils, causing problems. desirable.

In the aging step, the rare earth metal ion of the chelate-rare earth metal ion complex and the oxidant react in the metal nanoparticle-chelate-rare earth metal ion mixed solution to form a rare earth metal hydroxide, which is hydrolyzed to form a rare earth metal oxide film. Happens. For example, when the rare earth metal ion is cerium ion (Ce ³⁺ ), the cerium ion and the hydroxide ion of the ammonium salt react to form cerium hydroxide (Ce (OH) ₃ ), which is hydrolyzed to form a cerium oxide film ( CeO ₂ ).

In more detail, the metal nanoparticles surrounded by the surfactant have a positive charge, and the complex of the chelate and the rare earth metal ions has a negative charge, thereby inducing a reaction by an electrostatic force. Thereafter, the rare earth metal ions are oxidized by hydroxide ions in a aging step at a predetermined temperature or more, and the thickness of the shell of the rare earth metal oxide film formed through this process is uniform. In addition, it is possible to control the thickness of the shell in nanoscale by adjusting the amount and concentration of the reactants. The prepared metal / ceramic composite nanostructures exhibit excellent stability at high temperatures by the rare earth metal oxide film and have excellent dispersibility because physical dispersion of the metal nanoparticles is achieved by the rare earth metal oxide film.

The present invention may further include a calcination step of separating and heat-treating the metal / ceramic composite nanostructures generated after the aging step. Separation of the metal / ceramic composite nanostructures generated may be performed through centrifugation. The heat treatment removes unreacted organic substances, and the micro-pores (microore, pores 2 nm or less) and meso pores (mesopore, pores 2 nm to 50 nm) in the rare earth metal oxide film of the metal / ceramic composite nanostructure through the process of burning the organic substances. ) Is formed. The heat treatment is preferably performed at a temperature of 300 ° C. to 400 ° C., preferably 2 to 5 hours. When the heat treatment is less than 300 ℃ temperature unreacted organics are not removed all the impurities remain in the nanostructure, if the heat treatment exceeds 400 ℃ is preferably economical because it is made within the above range. In addition, when the heat treatment is less than 2 hours, unreacted organic matters remain, and if the heat treatment for more than 5 hours is economical, it is preferable to be made within the above range.

Meanwhile, the metal / ceramic composite nanostructure manufactured by the method described above may have a uniform thickness of the shell, and the metal / ceramic composite nanostructure in which the thickness of the shell is adjusted according to the amount and concentration of the reactants. The metal / ceramic composite nanostructure is a core-shell structure in which a rare earth metal oxide film is wrapped around the metal nanoparticles. When the metal / ceramic composite nanostructure is manufactured by the manufacturing method of the present invention, the thickness of the rare earth metal oxide film can be controlled and thus can be used in various applications.

The metal / ceramic composite nanostructure has a rare earth metal oxide film having a thickness of 1 nm to 200 nm, and when the metal / ceramic composite nanostructure has a rare earth metal oxide film having a thickness of less than 1 nm, thermal stability is easily degraded, which causes a problem of easy destruction at high temperatures. When the metal / ceramic composite nanostructure has a rare earth metal oxide film having a thickness of more than 200 nm, thermal stability is secured, but when used as a catalyst, it is preferable to have a rare earth metal oxide film within the above range because of a problem of inferior reactivity. However, if necessary, the thickness of the rare earth metal oxide film can be controlled.

In addition, the present invention can be used as a catalyst metal / ceramic composite nanostructure prepared by the above method. The catalyst may be used as a chemical catalyst and an electrochemical catalyst. When used as a chemical catalyst, it is typically applied to water gas shift reaction (WGSR), reverse water gas shift reaction (RWGSR), automobile emission control catalyst, reforming, etc. When used as a catalyst can be used in fuel cells, electrolyzers, batteries (battery).

Example 1 Preparation of Metal / Ceramic Composite Nanostructures

0.5 ml of platinum (Pt) nanoparticle colloid solution with TTAB surfactant was mixed with 40 ml of 0.025 M TTAB aqueous solution in which TTAB was dissolved in water to prepare a surfactant metal nanoparticle solution. In another reactor, 0.4 ml of ammonia water was added to 40 ml of water, 0.4 mmol of EDTA was dissolved to prepare a chelating solution (EDTA-NH ₃ ), and 2 ml of the prepared chelating solution was added to the surfactant metal nanoparticle solution. A mixed solution was prepared. 0.2 ml of cerium ion solution was added to the metal nanoparticle-chelate mixed solution to prepare a metal nanoparticle-chelate-rare earth metal ion mixed solution. After shaking gently for about 1 minute to mix, the metal nanoparticle-chelate-rare earth metal ion mixed solution was put into a 90 ° C. oven for 12 hours to mature. The metal nanoparticle-chelate-rare earth metal ion mixed solution, which was matured and completed, was placed in a centrifuge and left at 5000 rpm for 15 minutes. After removing the metal nanoparticle-chelate-rare earth metal ion mixed solution reactor from the centrifuge, the synthesized metal / ceramic composite nanostructure was filtered out, and the filtered metal / ceramic composite nanostructure was filtered at 300 ° C. for 5 hours. Heat treatment to remove unreacted organics.

Example 2 Preparation of Metal Nanoparticle Colloid Solution Coated with Surfactant

1) 12.5mL 400mM TTAB solution was added to a 100mL round flask, and 5mL 10mM K ₂ PtCl ₄ aqueous solution and 29.5 mL of water were mixed.

2) The mixed solution was stirred at 300 rpm for 10 minutes at room temperature.

3) The mixed solution was turned into a 50 ° C oil bath, and stirred at 300 rpm for 10 minutes.

4) In the transparent mixed solution, 3 mL 500 mM ice-cooled NaBH ₄ was placed in a rubber stopper attached to a flask branch (maintained at 50 ° C. and stirred at 300 rpm in an oil bath).

5) Hydrogen gas generated inside the flask was discharged through the syringe needle for 15 minutes (maintained at 50 ° C. and stirred at 300 rpm in an oil bath).

6) After 15 minutes, the syringe needle was removed and the mixed solution was kept at 50 ° C. for 12 hours 30 minutes and maintained at 300 rpm in an oil bath.

7) The prepared metal nanoparticle colloidal solution was centrifuged once at 3000 rpm for 30 minutes, and the supernatant was centrifuged twice at 15 minutes at 12000 rpm.

8) Finally, the synthesized metal nanoparticle colloidal solution was dispersed again in 5 mL of distilled water and then used for core-shell synthesis.

Example 3 Preparation of Metal Nanoparticle-chelate Mixing Solution

In order to prepare a metal nanoparticle colloidal solution coated with a surfactant, 0.25ml to 2.5ml was added per 100ml of water, and an aqueous surfactant solution was prepared by adding 0.841g of TTAB per 100g of water. Chelating solution was prepared by diluting chelating material and ammonia water in water and EDTA was used as the chelating material. To prepare the chelate solution, 0.38 ml of ammonia water was added to 40 ml of water, and 0.4 mmol of chelating material (EDTA) was added and mixed. The prepared chelate solution was prepared by adding 1 ml to 10 ml of the surfactant metal nanoparticle solution to prepare a metal nanoparticle-chelate mixed solution.

Experimental Example

2 to 5 are TEM photographs of the metal / ceramic composite nanostructures prepared by the above method. Looking at Figure 2 it can be seen that the cerium oxide film is formed on the platinum core, the cerium oxide film having a different thickness is produced according to the amount of the cerium ion solution and the chelate solution. As a result, it can be seen that the thickness of the cerium oxide film can be controlled on a nanoscale by controlling the amounts of the cerium ion solution and the chelate solution.

FIG. 3 is a TEM photograph after heat treatment of the platinum (core) -cerium oxide film (shell), which is the metal / ceramic composite nanostructure, wherein the platinum (core) -cerium oxide film (shell) is 300 ° C. and 400, respectively. It can be seen that despite the heat treatment at 2 ° C. for 2 hours, the core is not broken and the metal / ceramic composite nanostructure of the core-shell structure is maintained.

4 is a TEM photograph of the platinum (core) -cerium oxide film (shell) after heat treatment at 300 ° C. for 5 hours, and the core-shell structure is not broken even after heat treatment at 300 ° C. for 5 hours. It can be seen that the metal / ceramic composite nano structure is maintained.

FIG. 5 is a TEM photograph of the platinum (core) -cerium oxide film (shell) after heat treatment at 700 ° C. for 3 hours, respectively. The core-shell is not destroyed even after heat treatment at 700 ° C. for 3 hours. The metal / ceramic composite nano structure of the structure was maintained.

Therefore, it can be seen that the platinum (core) -cerium oxide film (shell), which is a metal / ceramic composite nanostructure produced as a result, has excellent thermal stability.

Claims (15)

Preparing a metal nanoparticle solution prepared by mixing a metal nanoparticle colloidal solution coated with a surfactant and an aqueous solution of a surfactant dissolved in water; Preparing a metal nanoparticle-chelate mixed solution for mixing a chelate solution with the surfactant metal nanoparticle solution; Preparing a metal nanoparticle-chelate-rare earth metal ion mixed solution for mixing a rare earth metal ion solution with the metal nanoparticle-chelate mixed solution; And And a aging step of aging the metal nanoparticle-chelate-rare earth metal ion mixed solution. The method of claim 1, The aging step is a metal / ceramic composite nanostructure manufacturing method characterized in that for maintaining the metal nano-particles-chelate-rare earth metal ion mixed solution for 1 hour to 24 hours at 60 ℃ to 90 ℃ temperature. The method of claim 1, The calcination step of separating and heat-treating the metal / ceramic composite nanostructures generated after the aging step; further comprising a metal / ceramic composite nanostructures manufacturing method. The method of claim 1, The metal nanoparticles are selected from the group consisting of gold (Au), silver (Ag), cobalt (Co), copper (Cu), iron (Fe), nickel (Ni), palladium (Pd), and platinum (Pt). Method for producing a metal / ceramic composite nanostructure, characterized in that at least one. The method of claim 1, Metal / ceramic composite nanostructure manufacturing method characterized in that the particle diameter of the metal nanoparticles is 2nm to 200nm. The method of claim 1, The surfactant is a group consisting of Tetradecyl Trimethyl Ammonium Bromide (TTAB), Dodecyl Trimethyl Ammonium Bromide (DTAB), and Cetyl Trimethyl Ammonium Bromide (CTAB) Method for producing a metal / ceramic composite nanostructures, characterized in that at least one selected from. The method of claim 1, The metal / ceramic composite nanostructure, wherein the surfactant metal nanoparticle solution is 0.1 to 1 volume ratio, the chelating solution is 1 to 10 volume ratio, and the rare earth metal ion solution is 0.1 to 1 volume ratio to the 40 volume ratio of water. Manufacturing method. The method of claim 1, The chelating agent is ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), (1,2-cyclohexylene dinitrilo) tetraacetic acid ((1,2-cyclohexylene dinitrilo) tetraacetic acid , CyDTA), diethylene triamine pentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA-OH), glycol-bis (2-aminoethylether) -N, N, N ' Glycol-bis (2-aminoethylether) -N, N, N ', N'-tetraacetic acid (GEDTA), triethylenetetraminehexaacetic acid (TTHA), dihydroxyethylglycine (Dihydroxy Ethyl Glycine, DHEG), iminodiacetate (IDA), metal-Ethylenediaminetetraacetic acid (Me-EDTA), Hydroxy Imminodiacetic acid (HIDA), and EDTPO Method for producing a metal / ceramic composite nanostructures that at least one member selected from the group consisting of which is characterized. The method of claim 1, The chelating solution is a metal / ceramic composite nanostructures manufacturing method characterized in that is prepared by mixing the oxidizing agent and chelating agent in water. The method of claim 9, The oxidizing agent is an ammonium salt, ammonium hydroxide (NH ₄ OH), urea (UREA), and hexamethylenetetramine (hexamethylenetetramine, HMTA) is a metal / ceramic composite nanostructure manufacturing method characterized in that at least one selected from the group consisting of. . The method of claim 1, The rare earth metal ion solution is ionized rare earth metal, and the rare earth metal is cerium (Ce), samarium (Sm), gadolindium (Gd), lanthanum (La), praseodymium (Pr), yttrium (Y), neodymium At least one selected from the group consisting of (Nd), europium (Eu), erbium (Er), dysprosium (Dy), holmium (Ho), tolium (Tm), ytterbium (Yb), and ruthenium (Lu) Metal / ceramic composite nanostructure manufacturing method characterized in that. The method of claim 1, The rare earth metal ion solution in the metal nanoparticle-chelate-rare earth metal ion mixed solution manufacturing step is prepared by diluting the rare earth metal ion precursor in water. Metal / ceramic composite nanostructures prepared by the method according to any one of claims 1 to 12. The method of claim 13,  The metal / ceramic composite nanostructure is a metal / ceramic composite nanostructure, characterized in that it has a rare earth metal oxide film of 1nm to 200nm. A catalyst comprising a metal / ceramic composite nanostructure prepared by the method of any one of claims 1 to 12.

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