KR102169849B1 - Metal nano particle, catalyst and fuel cell comprising the same and method for manufacturing thereof - Google Patents

Abstract

The present specification relates to a metal nanoparticle, a catalyst and a fuel cell including the same, and a method of manufacturing the same.

Description

Metal nanoparticles, catalyst and fuel cell including the same, and a method for manufacturing the same {METAL NANO PARTICLE, CATALYST AND FUEL CELL COMPRISING THE SAME AND METHOD FOR MANUFACTURING THEREOF}

The present specification relates to a metal nanoparticle, a catalyst and a fuel cell including the same, and a method of manufacturing the same.

Nanoparticles are particles having a nanoscale particle size, and are optically different from bulk materials due to the quantum confinement effect and large specific surface area in which the energy required for electron transfer changes according to the size of the material. , Shows electrical and magnetic properties. Therefore, due to these properties, a lot of interest has been focused on the applicability in the catalytic field, the electric magnetic field, the optical field, and the medical field. Nanoparticles can be said to be an intermediate between bulk and molecules, and the synthesis of nanoparticles is possible in terms of two approaches, namely the "Top-down" approach and the "Bottom-up" approach.

Methods of synthesizing metal nanoparticles include a method of reducing metal ions with a reducing agent in a solution, a method using gamma rays, and an electrochemical method, but conventional methods are difficult to synthesize nanoparticles having a uniform size and shape, or an organic solvent. It was difficult to mass-produce economically, such as environmental pollution and high cost problems. Therefore, the development of high-quality nanoparticles of uniform size is required.

Korean Patent Publication No. 10-2005-0098818

The present specification is to provide a metal nanoparticle, a catalyst and a fuel cell including the same, and a method of manufacturing the same.

The present specification is a hollow core (core) portion; A first shell portion in a bowl shape including an alloy of platinum and a transition metal; And it provides a metal nanoparticle including one or more bowl-type particles provided on the first shell portion and including a second shell portion made of platinum.

In addition, the present specification provides a catalyst including the metal nanoparticles.

In addition, the present specification includes an anode catalyst layer, a cathode catalyst layer, and a polymer electrolyte membrane provided between the anode catalyst layer and the cathode catalyst layer, and at least one of the anode catalyst layer and the cathode catalyst layer includes the metal nanoparticles. to provide.

In addition, the present specification provides a fuel cell including a membrane electrode assembly as a unit cell.

In addition, the present specification includes a first solvent, a platinum salt providing a platinum ion or an atomic group ion including the platinum ion in the first solvent, a transition metal ion or an atomic group ion including the transition metal ion in the first solvent Forming a first solution comprising a transition metal salt to provide, a first surfactant for forming micelles in the first solvent, and a second surfactant for forming micelles in the first solvent together with the first surfactant ; Forming metal nanoparticles having a bowl-shaped first shell part by adding a reducing agent to the first solution; And forming a second shell part made of platinum on the first shell part of the metal nanoparticle by using a second solution in which a platinum salt is added to the second solvent.

There is an advantage in that dissolution of the transition metal is suppressed in the metal nanoparticles according to the present specification.

The catalyst having metal nanoparticles according to the present specification has an advantage of having a wide active surface area.

1 is a schematic diagram showing a principle of generating electricity in a fuel cell.
2 is a diagram schematically showing the structure of a membrane electrode assembly for a fuel cell.
3 is a diagram schematically showing an embodiment of a fuel cell.
4 is a cross-sectional view of a metal nanoparticle according to a first embodiment of the present specification.
5 is a cross-sectional view of a metal nanoparticle according to a second embodiment of the present specification.
6 to 7 are transmission electron microscopy (TEM) pictures of the particles synthesized in Comparative Example 1.
8 is a transmission electron microscope (TEM) photograph of the particles synthesized in Example 1.

Hereinafter, the present specification will be described in detail.

The present specification is a hollow core (core) portion; A first shell portion in a bowl shape including an alloy of platinum and a transition metal; And it provides a metal nanoparticle including one or more bowl-type particles provided on the first shell portion and including a second shell portion made of platinum.

Individual particle diameters of the plurality of metal nanoparticles formed in the exemplary embodiment of the present application may be within a range of 80% to 120% of the average particle diameter of the metal nanoparticles. Specifically, the particle diameter of the metal nanoparticles may be within a range of 90% to 110% of the average particle diameter of the metal nanoparticles. If it is out of the above range, since the size of the metal nanoparticles becomes non-uniform as a whole, it may be difficult to secure unique physical properties required by the metal nanoparticles. For example, when metal nanoparticles outside the range of 80% to 120% of the average particle diameter of the metal nanoparticles are used as a catalyst, the activity of the catalyst may be somewhat insufficient.

The metal nanoparticles include bowl-type particles. The metal nanoparticles include one or more bowl-type particles, and some or all of the metal nanoparticles may be bowl-type particles.

The bowl-type particles may be in a form in which two or more bowl-type particles are spaced apart, or two or more bowl-type particles are partially in contact with each other.

In the present specification, the bowl-type particles or metal nanoparticles in which two or more bowl-type particles are partially in contact with each other may mean that the size of the cavity occupies 30% or more of the total shell portion. That is, the bowl-type particle may mean that the cavity is continuously formed so that 30% or more of the surface of the nanoparticle does not form a shell part.

In addition, the metal nanoparticles in a form in which the two or more bowl-type particles are partially in contact with each other may mean that the cavity is continuously formed, so that a part of the metal nanoparticles is split.

In the present specification, the cavity may mean an empty space continuous from an area of the outer surface of the metal nanoparticle. The cavity of the present specification may be formed in the form of one tunnel from an area of the outer surface of the shell part. The tunnel shape may be a straight line, may be a continuous shape of a curve or a straight line, and may be a continuous shape in which a curve and a straight line are mixed.

In the present specification, the bowl type may mean that a curved region includes at least one in cross section. Alternatively, the bowl type may mean that a curved area and a straight area are mixed on a cross section. Alternatively, the bowl shape may be a hemispherical shape, and the hemispherical shape may be a shape in which a region of the sphere is removed, rather than a shape divided so as to pass through the center of the sphere. Furthermore, the sphere does not mean only a perfect sphere, but may include an approximate sphere shape. For example, the outer surface of the sphere may not be flat, and the radius of curvature of the sphere may not be constant. Alternatively, the bowl-type particles of the present specification may mean that 30% or more and 80% or less of the entire shell portion of the hollow nanoparticles is not continuously formed.

The average particle diameter of the bowl-type particles may be 20 nm or less, more specifically 12 nm or less, or 10 nm or less, or 8 nm or less. Alternatively, the bowl-type particles may have an average particle diameter of 6 nm or less. The bowl-type particles may have an average particle diameter of 1 nm or more. When the bowl-type particles have a particle diameter of 20 nm or less, there is a great advantage that nanoparticles can be used in various fields. Further, it is more preferable when the bowl-type particles have a particle diameter of 10 nm or less. In addition, when the bowl-type particle has a particle diameter of 10 nm or less, 8 nm or less, or 6 nm or less, the surface area of the particle becomes wider, thereby increasing the possibility of application that can be used in various fields. For example, when bowl-type particles formed in the particle size range are used as a catalyst, the efficiency may be remarkably increased.

According to the exemplary embodiment of the present application, the average particle diameter of the hollow metal nanoparticles is measured for 200 or more hollow metal nanoparticles using a graphic software (MAC-View), and the average particle diameter is measured through the obtained statistical distribution. Can mean value.

According to the exemplary embodiment of the present application, the average particle diameter of the hollow metal nanoparticles may be determined by measuring the crystal size of the particles through XRD analysis.

According to the exemplary embodiment of the present application, the average particle diameter of the bowl-type particles may be 1 nm or more and 20 nm or less.

According to the exemplary embodiment of the present application, the average particle diameter of the bowl-type particles may be 1 nm or more and 12 nm or less.

According to the exemplary embodiment of the present application, the average particle diameter of the bowl-type particles may be 1 nm or more and 10 nm or less.

According to the exemplary embodiment of the present application, the average particle diameter of the bowl-type particles may be 1 nm or more and 8 nm or less.

According to the exemplary embodiment of the present application, the average particle diameter of the bowl-type particles may be 1 nm or more and 6 nm or less.

In the present specification, the term hollow means that the core portion of the metal nanoparticle is empty. In addition, the hollow may be used in the same meaning as the hollow core. The hollow includes the terms hollow, hole, void, and porous. The hollow may include a space in which 50% by volume or more, specifically 70% by volume or more, and more specifically 80% by volume or more, does not exist. Alternatively, the hollow may include a space in which 50% by volume or more, specifically 70% by volume or more, and more specifically 80% by volume or more, is empty. Or a space having an internal porosity of 50 vol% or more, specifically 70 vol% or more, and more specifically 80 vol% or more.

According to the exemplary embodiment of the present application, the volume of the hollow core may be 50% by volume or more, specifically 70% by volume or more, and more specifically 80% by volume or more of the total volume of the metal nanoparticles.

The metal nanoparticles may include a surfactant in the hollow core. Specifically, the hollow nanoparticles may include an anionic surfactant or a cationic surfactant in the hollow core.

According to the exemplary embodiment of the present application, the first shell portion of the bowl-type particle may be formed of a metal including platinum and a transition metal. That is, the shell portion of the bowl-type particle of the present invention may be formed of a metal other than a metal oxide.

The first shell portion of the present application may exist in a part of the outside of the hollow, and may exist in a bowl shape surrounding the hollow. Specifically, according to the exemplary embodiment of the present application, the first shell portion may be formed on a part of an outer surface of the hollow core portion. That is, the first shell portion of the present application may constitute the shape of the bowl-type particle. According to the exemplary embodiment of the present application, the bowl-type particles may have a shape such as a bowl having an opening and an empty inside.

The transition metal is not particularly limited as long as it can form an alloy with platinum. For example, ruthenium (Ru), rhodium (Rh), molybdenum (Mo), osmium (Os), iridium (Ir), rhenium (Re), Vanadium (V), tungsten (W), cobalt (Co), iron (Fe), selenium (Se), nickel (Ni), bismuth (Bi), tin (Sn), chromium (Cr), titanium (Ti), It may contain at least one of cerium (Ce) and copper (Cu).

The atomic percentage ratio of platinum and the transition metal of the first shell portion may be 1:5 to 10:1.

The atomic percentage ratio of platinum and the transition metal of the first shell portion may be 6:4 to 10:1, and specifically, 8:2 to 10:1.

The average thickness of the first shell portion may be 5 nm or less, specifically more than 0 nm and 5 nm or less, or 0.25 nm or more and 5 nm or less, and more specifically, more than 0 nm and 3 nm or less, or 0.25 nm or more and 3 nm or less.

The second shell portion is provided on the first shell portion. That is, it means that the second shell portion is formed on at least a part of the surface of the first shell portion. Specifically, the second shell portion may cover the outer surface of the first shell portion discontinuously or may cover the entire outer surface of the first shell portion. In this case, there is an advantage in that dissolution of the transition metal from the metal nanoparticles is suppressed.

When the transition metal is dissolved from the metal nanoparticles, the dissolved transition metal melts into the electrolyte membrane and interferes with the function of the electrolyte membrane, thereby deteriorating the fuel cell performance.

When the metal nanoparticles of the present specification are supported on a carrier, the second shell portion non-continuously covers the outer surface of the surface of the first shell portion other than the surface in contact with the carrier, or contacts the carrier in the surface of the first shell portion It can cover the entire outer surface, except for the surface.

The second shell portion is made of platinum and may contain some impurities in the process, but in principle, it refers to a layer formed on the first shell portion with only platinum.

The average thickness of the second shell portion may be 5 nm or less, specifically more than 0 nm and 5 nm or less, or 0.25 nm or more and 5 nm or less, and more specifically, more than 0 nm and 3 nm or less, or 0.25 nm or more and 2 nm or less.

The metal nanoparticles may further include a carrier that supports bowl-type particles.

The carrier may be a carbon-based carrier, for example, graphite (graphite), graphene, activated carbon, mesoporous carbon, carbon black, acetylene black, denka black, kaetchen black, activated carbon, porous carbon, carbon nanotubes, any one or two or more kinds of mixtures selected from a carbon nano fiber, carbon nano horn, carbon nano ring, carbon nanowire, the group consisting of fullerene (C ₆₀₎ and Super P black (Super P black) This can be a good example.

The carrier may be a carrier coated with a cationic polymer.

The cationic polymer is not particularly limited as long as it has a cationic group, but may be a polymer including at least one of an amine group and an imine group.

The cationic polymer may include at least one of polyallylamine hydrochloride (PAH) and polyalkyleneimine.

The polyalkyleneimine may have an aliphatic hydrocarbon main chain and may be a polymer including at least 10 amine groups in the main chain and side chain. The amine group at this time includes a primary amine group, a secondary amine group, a tertiary amine group, and a quaternary amine group, and the amine groups included in the main and side chains of the polyalkyleneimine are primary amine groups, secondary amine groups, At least one of the tertiary amine group and the quaternary amine group may be 10 or more.

The weight average molecular weight of the polyalkyleneimine may be 500 or more and 1,000,000 or less.

The polyalkyleneimine may include at least one of a repeating unit represented by Formula 1 below and a repeating unit represented by Formula 2 below.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, E1 and E2 are each independently an alkylene group having 2 to 10 carbon atoms, R is a substituent represented by any one of the following Formulas 3 to 5, and o and p are each an integer of 1 to 1000,

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, A1 to A3 are each independently an alkylene group having 2 to 10 carbon atoms, and R1 to R3 are each independently a substituent represented by any one of the following formulas 6 to 8,

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 6 to 8, A4 to A6 are each independently an alkylene group having 2 to 10 carbon atoms, and R4 to R6 are each independently a substituent represented by the following formula (9),

[Formula 9]

In Formula 9, A7 is an alkylene group having 2 to 10 carbon atoms.

The polyalkyleneimine may include at least one of a compound represented by Formula 10 below and a compound represented by Formula 11.

[Formula 10]

[Formula 11]

In Formulas 10 and 11, X1, X2, Y1, Y2 and Y3 are each independently an alkylene group having 2 to 10 carbon atoms, R is a substituent represented by any one of the following formulas 3 to 5, and q is 1 to 1000 Is an integer, n and m are each an integer of 1 to 5, l is an integer of 1 to 200,

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, A1 to A3 are each independently an alkylene group having 2 to 10 carbon atoms, and R1 to R3 are each independently a substituent represented by any one of the following formulas 6 to 8,

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 6 to 8, A4 to A6 are each independently an alkylene group having 2 to 10 carbon atoms, and R4 to R6 are each independently a substituent represented by the following formula (9),

[Formula 9]

In Formula 9, A7 is an alkylene group having 2 to 10 carbon atoms.

는 치환기의 치환위치를 의미한다.In this specification,

Means a substitution position of a substituent.

In the present specification, the alkylene group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 10. Specific examples include an ethylene group, a propylene group, an isopropylene group, a butylene group, a t-butylene group, a pentylene group, a hexylene group and a heptylene group, but are not limited thereto.

The polyalkyleneimine may be polyethyleneimine (PEI).

The metal nanoparticles according to the present specification may be used in place of conventional nanoparticles in a field in which nanoparticles can be used in general. The metal nanoparticles of the present invention have a very small size and a wider specific surface area compared to the conventional nanoparticles, and thus may exhibit superior activity compared to the conventional nanoparticles. Specifically, the metal nanoparticles of the present invention can be used in various fields such as catalysts, drug delivery, and gas sensors. The metal nanoparticles may be used as a catalyst as an active substance preparation in cosmetics, pesticides, animal nutritional supplements or food supplements, and may be used as pigments in electronic products, optical products or polymers.

The present specification provides a catalyst including the metal nanoparticles.

The electrochemical cell refers to a cell using a chemical reaction, and if a polymer electrolyte membrane is provided, the type is not particularly limited. For example, the electrochemical cell may be a fuel cell, a metal secondary cell, or a flow cell.

The present specification provides an electrochemical cell module including an electrochemical cell as a unit cell.

The electrochemical cell module may be formed by stacking by inserting a bipolar plate between flow cells according to an exemplary embodiment of the present application.

Specifically, the battery module may be used as a power source for an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

The present specification provides a membrane electrode assembly comprising an anode catalyst layer, a cathode catalyst layer, and a polymer electrolyte membrane provided between the anode catalyst layer and the cathode catalyst layer, and at least one of the anode catalyst layer and the cathode catalyst layer includes the metal nanoparticles. .

The membrane electrode assembly may further include an anode gas diffusion layer provided on a surface opposite to a surface of the anode catalyst layer on which a polymer electrolyte membrane is provided, and a cathode gas diffusion layer provided on a surface opposite to a surface of the cathode catalyst layer on which the polymer electrolyte membrane is provided. .

The present specification provides a fuel cell including a membrane electrode assembly as a unit cell.

1 schematically shows the principle of generating electricity in a fuel cell. In a fuel cell, the most basic unit for generating electricity is a membrane electrode assembly (MEA), which is an electrolyte membrane (M) and the electrolyte membrane (M). It consists of an anode (A) and a cathode (C) formed on both sides of the. Referring to Fig. Showing the electricity generating principle of a fuel cell 1, an anode (A) in the hydrogen or methanol, butane and the oxidation of the fuel (F) of the hydrocarbon and so on up the hydrogen ions (H ⁺⁾ and electron (e ^-), such as Is generated, and hydrogen ions move to the cathode (C) through the electrolyte membrane (M). In the cathode (C), hydrogen ions transferred through the electrolyte membrane (M), an oxidizing agent (O) such as oxygen, and electrons react to generate water (W). This reaction causes the movement of electrons to the external circuit.

FIG. 2 schematically shows the structure of a membrane electrode assembly for a fuel cell. The membrane electrode assembly for a fuel cell includes an electrolyte membrane 10, a cathode 50 positioned opposite to each other with the electrolyte membrane 10 interposed therebetween. An anode 51 may be provided. The cathode is provided with a cathode catalyst layer 20 and a cathode gas diffusion layer 40 sequentially from the electrolyte membrane 10, and the anode catalyst layer 21 and the anode gas diffusion layer 41 sequentially from the electrolyte membrane 10 Can be provided.

The catalyst according to the present specification may be included in at least one of a cathode catalyst layer and an anode catalyst layer in the membrane electrode assembly.

3 schematically shows a structure of a fuel cell, and the fuel cell includes a stack 60, an oxidizer supply unit 70, and a fuel supply unit 80.

The stack 60 includes one or two or more membrane electrode assemblies described above, and when two or more membrane electrode assemblies are included, a separator interposed therebetween. The separator serves to prevent the membrane electrode assemblies from being electrically connected and to deliver fuel and oxidizing agent supplied from the outside to the membrane electrode assemblies.

The oxidant supply unit 70 serves to supply the oxidant to the stack 60. Oxygen is typically used as the oxidizing agent, and oxygen or air may be injected into the oxidizing agent supply unit 70 to be used.

The fuel supply unit 80 serves to supply fuel to the stack 60, and includes a fuel tank 81 for storing fuel and a pump 82 for supplying fuel stored in the fuel tank 81 to the stack 60. Can be configured. As the fuel, gaseous or liquid hydrogen or hydrocarbon fuel may be used. Examples of hydrocarbon fuels include methanol, ethanol, propanol, butanol or natural gas.

At least one of the anode catalyst layer and the cathode catalyst layer may include metal nanoparticles according to the present specification as a catalyst.

Each of the anode catalyst layer and the cathode catalyst layer may include an ionomer.

When the anode catalyst layer contains the metal nanoparticles as a catalyst, the ratio of the ionomer and the catalyst (Ionomer/Catalyte, I/C) of the anode catalyst layer is 0.3 to 1.

When the cathode catalyst layer contains the metal nanoparticles as a catalyst, the ratio of the ionomer and the catalyst (Ionomer/Catalyte, I/C) of the cathode catalyst layer is 0.3 to 1.

The ionomer serves to provide a passage for ions generated by a reaction between a catalyst such as hydrogen or methanol and a fuel to move to the electrolyte membrane.

The ionomer may be a polymer having a cation exchange group selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phosphonic acid group and derivatives thereof in the side chain. Specifically, the ionomer is a fluorine-based polymer, Nafion, a benzimidazole-based polymer, a polyimide-based polymer, a polyetherimide-based polymer, a polyphenylene sulfide-based polymer, a polysulfone-based polymer, a polyethersulfone-based polymer, and a polyether. At least one hydrogen ion conductive polymer selected from a ketone-based polymer, a polyether-etherketone-based polymer, or a polyphenylquinoxaline-based polymer may be included.

The present specification provides a first solvent, a platinum salt providing a platinum ion or an atomic group ion including the platinum ion in the first solvent, a transition metal ion or an atomic group ion including the transition metal ion in the first solvent Forming a first solution comprising a transition metal salt, a first surfactant for forming micelles in the first solvent, and a second surfactant for forming micelles in the first solvent together with the first surfactant; Forming metal nanoparticles having a bowl-shaped first shell part by adding a reducing agent to the first solution; And forming a second shell part made of platinum on the first shell part of the metal nanoparticle by using a second solution in which a platinum salt is added to the second solvent.

The manufacturing method according to the exemplary embodiment of the present application has an advantage in that the reduction potential between platinum and the transition metal is not considered because the reduction potential difference is not used. Since it uses a charge between metal ions, it has the advantage of being a simpler method than a conventional manufacturing method and an easy mass production method.

All steps of the manufacturing method may be performed at a temperature in the range of 4° C. or more and 90° C. or less, more specifically 15° C. or more and 80° C. or less. All steps of the manufacturing method may be performed at room temperature. Specifically, all steps of the manufacturing method may be performed at a temperature in the range of 4° C. or more and 35° C. or less, and more specifically 15° C. or more and 28° C. or less.

The method for producing metal nanoparticles of the present specification includes a first solvent, a platinum salt providing platinum ions or atomic unit ions including the platinum ions in the first solvent, and a transition metal ion or the transition metal ions in the first solvent. A first comprising a transition metal salt providing an atomic group ion containing, a first surfactant for forming micelles in the first solvent, and a second surfactant for forming micelles in the first solvent together with the first surfactant And forming a solution.

The step of forming the first solution may be performed at a temperature in the range of 4° C. or more and 90° C. or less, more specifically 15° C. or more and 80° C. or less. When the solvent is used as an organic solvent, there is a problem that it must be prepared at a high temperature of over 100°C. The present invention has a large cost reduction effect.

The step of forming the first solution may be performed at room temperature, specifically at a temperature in the range of 4° C. or more and 35° C. or less, and more specifically 15° C. or more and 28° C. or less. Since the present invention can be manufactured at room temperature, the manufacturing method is simple, so there is an advantage in the process and the cost reduction effect is large.

The step of forming the first solution may be performed for 5 to 120 minutes, more specifically for 10 to 90 minutes, and even more specifically for 20 to 60 minutes.

According to an embodiment of the present invention, the first solvent may be a solvent containing water. Specifically, in one embodiment of the present invention, the first solvent dissolves a platinum salt and a transition metal salt, and may be water or a mixture of water and a C ₁ -C ₆ alcohol, and specifically water. In the present invention, since an organic solvent is not used as a solvent, a post-treatment process for treating the organic solvent is not required in the manufacturing process, thus reducing cost and preventing environmental pollution.

The manufacturing method includes the platinum ions or atomic group ions including platinum ions; And the transition metal ion or an atomic group ion including the transition metal ion may form a shell portion of the metal nanoparticle.

In the exemplary embodiment of the present application, the platinum salt and the transition metal salt are not particularly limited as long as they are ionized in a solution to provide platinum ions and transition metal ions. For example, the platinum salt and the transition metal salt may be a nitrate, a halide, a hydroxide, or a sulfur oxide of platinum and a transition metal, respectively.

In the first solution, the molar ratio of the platinum salt and the transition metal salt may be 1:1 to 1:10, and specifically 1:2 to 1:5.

The manufacturing method may include forming a hollow inner region of the micelle formed by the first surfactant.

The forming of the first solution may include forming micelles in the solution of the first and second surfactants.

According to the exemplary embodiment of the present specification, the platinum ion or the atomic group ion including the platinum ion has a charge opposite to that of the outer end of the first surfactant, and includes the transition metal ion or the transition metal ion. The atomic unit ion may have a charge equal to that of the outer end of the first surfactant.

In the present specification, the outer end of the surfactant may mean an outer portion of the micelle of the first or second surfactant forming a micelle. The outer end of the surfactant in the present specification may mean the head of the surfactant. In addition, the outer end of the present specification may determine the charge of the surfactant.

In addition, the surfactant of the present specification may be classified as ionic or nonionic depending on the type of the outer end, and the ionicity may be positive, negative, zwitterionic or amphoteric. The zwitterionic surfactant contains both positive and negative charges. If the positive and negative charges of the surfactant of the present specification are pH dependent, it may be an amphoteric surfactant, which may be zwitterionic in a certain pH range. Specifically, the anionic surfactant in the present specification may mean that the outer end of the surfactant has a negative charge, and the cationic surfactant may mean that the outer end of the surfactant has a positive charge.

According to an exemplary embodiment of the present specification, the preparation method includes a concentration of the second surfactant; Chain length; The size of the outer end; Alternatively, by controlling the type of charge, a cavity may be formed in one or two or more regions of the shell portion. The second surfactant is a concentration of the first surfactant; Chain length; The size of the outer end; And at least one of charge types may be different.

According to the exemplary embodiment of the present specification, the first surfactant may serve to form a micelle in a solution so that the metal ion or atomic group ion including the metal ion forms a shell portion, and the second surfactant is It may serve to form the cavity of the metal nanoparticles.

The forming of the first solution may include forming a cavity by adjusting the charge of the second surfactant to be different from that of the first surfactant.

Any one of the first surfactant and the second surfactant may be an anionic surfactant, and the other may be a cationic surfactant. That is, according to the exemplary embodiment of the present specification, the first and second surfactants may have different charges.

According to the exemplary embodiment of the present specification, when the first and second surfactants have different charges, a cavity of the metal nanoparticles may be formed even if the chains of the first and second surfactants have the same length. have. In this case, the outer ends of the second surfactant of the micelle and the outer ends of the first surfactant that are adjacent to each other exchange electric charges and become neutral, so that metal ions are not located. Therefore, the portion where the metal ion is not located does not form a shell portion, so that a cavity of the metal nanoparticles can be formed.

The first surfactant may be an anionic surfactant or a cationic surfactant, and the second surfactant may be a nonionic or amphoteric surfactant.

When the second surfactant is a nonionic surfactant, since no metal ions are located at the outer end of the second surfactant, a cavity of the metal nanoparticles can be formed. Therefore, when the second surfactant is nonionic, a cavity of the metal nanoparticles may be formed even when the length of the chain is the same as or different from that of the first surfactant.

When the second surfactant is an amphoteric surfactant, since no metal ions are located at the outer end of the second surfactant, a cavity of the metal nanoparticles can be formed. Therefore, when the second surfactant is zwitterionic, the cavity of the metal nanoparticles can be formed even when the length of the chain is the same as or different from the first surfactant.

The anionic surfactant of the present specification is ammonium lauryl sulfate, sodium 1-heptanesulfonate, sodium hexanesulfonate, Sodium dodecyl sulfate, triethanol ammonium dodecylbenzene sulfate, potassium laurate, triethanolamine stearate, lithium dodecyl sulfate, sodium lauryl sulfate, alkyl polyoxyethylene sulfate, sodium alginate, dioctyl sodium sulfosuccinate, phosphatidyl Glycerol, phosphatidyl inositol, phosphatidylserine, phosphatidic acid and salts thereof, glyceryl esters, sodium carboxymethylcellulose, bile acids and salts thereof, cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid, glycodeoxycholic acid, alkyl sulfonate , Aryl sulfonates, alkyl phosphates, alkyl phosphonates, stearic acid and salts thereof, calcium stearate, phosphate, carboxymethylcellulose sodium, dioctylsulfosuccinate, dialkyl esters of sodium sulfosuccinic acid, phospholipids and calcium carboxymethylcellulose It may be selected from the group consisting of. However, it is not limited thereto.

The cationic surfactant of the present specification is a quaternary ammonium compound, benzalkonium chloride, cetyltrimethylammonium bromide, chitosan, lauryldimethylbenzylammonium chloride, acyl carnitine hydrochloride, alkylpyridinium halide, cetyl pyridinium chloride , Cationic lipids, polymethylmethacrylate trimethylammonium bromide, sulfonium compounds, polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate, hexadecyltrimethyl ammonium bromide, phosphonium compounds, benzyl-di(2 -Chloroethyl)ethyl ammonium bromide, coconut trimethyl ammonium chloride, coconut trimethyl ammonium bromide, coconut methyl dihydroxyethyl ammonium chloride, coconut methyl dihydroxyethyl ammonium bromide, decyl triethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride bromide , N-alkyl (C ₁₂ -C ₁₅ ) dimethyl hydroxyethyl ammonium chloride, N-alkyl (C ₁₂ -C ₁₅ ) dimethyl hydroxyethyl ammonium chloride bromide, coconut dimethyl hydroxyethyl ammonium chloride, coconut dimethyl hydroxyethyl ammonium Bromide, myristyl trimethyl ammonium methyl sulfate, lauryl dimethyl benzyl ammonium chloride, lauryl dimethyl benzyl ammonium bromide, lauryl dimethyl (ethenoxy) 4 ammonium chloride, lauryl dimethyl (ethenoxy) tetraammonium bromide, N-alkyl (C ₁₂ -C ₁₈ ) Dimethylbenzyl ammonium chloride, N-alkyl (C ₁₄ -C ₁₈ ) Dimethyl-benzyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium chloride monohydrate, dimethyl didecyl ammonium chloride, N-alkyl (C ₁₂ -C ₁₄ )Dimethyl 1-naphthylmethyl ammonium chloride, trimethylammonium halide alkyl-trimethylammonium salt, dialkyl-dimethylammonium salt, lauryl trimethyl ammonium chloride, ethoxylated alkylamidoalkyldialkylammonium salt, ethoxylated tri Alkyl ammonium salt, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium chloride Ride monohydrate, N-alkyl (C ₁₂ -C ₁₄ ) dimethyl 1-naphthylmethyl ammonium chloride, dodecyldimethylbenzyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl Benzyl dimethyl ammonium bromide, alkyl (C ₁₂ ) trimethyl ammonium bromide, alkyl (C ₁₅ ) trimethyl ammonium bromide, alkyl (C ₁₇ ) trimethyl ammonium bromide, dodecylbenzyl triethyl ammonium chloride, polydiallyldimethylammonium chloride, dimethyl ammonium chloride , Alkyldimethylammonium halogenide, tricetyl methyl ammonium chloride, decyltrimethylammonium bromide, dodecyltriethylammonium bromide, tetradecyltrimethylammonium bromide, methyl trioctylammonium chloride, polyquat (POLYQUAT) 10, tetrabutylammonium bromide, Benzyl trimethylammonium bromide, choline ester, benzalkonium chloride, stearalkonium chloride, cetyl pyridinium bromide, cetyl pyridinium chloride, halide salt of quaternized polyoxyethylalkylamine, "MIRAPOL" ( Polyquaternium-2), “Alkaquat” (alkyl dimethyl benzylammonium chloride, manufactured by Rhodia), alkyl pyridinium salt, amine, amine salt, imide azolinium salt, protonation It may be selected from the group consisting of quaternary acrylamide, methylated quaternary polymer, cationic guar gum, benzalkonium chloride, dodecyl trimethyl ammonium bromide, triethanolamine, and poloxamine. However, it is not limited thereto.

The nonionic surfactant of the present specification is SPAN 60, polyoxyethylene fatty alcohol ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene castor oil derivative, sor Non-ester, glyceryl ester, glycerol monostearate, polyethylene glycol, polypropylene glycol, polypropylene glycol ester, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, arylalkyl polyether alcohol, polyoxyethylene polyoxypropylene copolymer , Poloxamer, poloxamine, methylcellulose, hydroxycellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylmethylcellulose phthalate, amorphous cellulose, polysaccharide, starch, Starch derivatives, hydroxyethyl starch, polyvinyl alcohol, triethanolamine stearate, amine oxide, dextran, glycerol, acacia gum, cholesterol, tragacanth, and polyvinylpyrrolidone may be selected from the group consisting of. .

The amphoteric surfactant of the present specification is N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, betaine, alkyl betaine, alkylamido betaine, amido propyl betaine , Cocoamphocarboxyglycinate, sacosinate aminopropionate, aminoglycinate, imidazolinium betaine, amphoteric midazoline, N-alkyl-N,N-dimethylammonio-1-propanesulfone Eight, It may be one selected from the group consisting of 3-cholamido-1-propyldimethylammonio-1-propanesulfonate, dodecylphosphocholine, and sulfo-betaine. However, it is not limited thereto.

Forming the first solution may include adjusting the size of the cavity by adjusting the size of the outer end of the second surfactant.

The forming of the first solution may include forming a cavity in the second surfactant region by adjusting the chain length of the second surfactant to be different from the chain length of the first surfactant. Specifically, by making the chain length of the second surfactant different from the chain length of the first surfactant, the metal salt bonded to the outer end of the second surfactant does not form the first shell portion of the metal nanoparticles. I can.

The chain length of the second surfactant may be 0.5 times or more and 2 times or less of the chain length of the first surfactant. Specifically, the chain length may be determined by the number of carbons.

According to the exemplary embodiment of the present specification, the forming of the first solution may include adjusting the size or number of the cavities by varying concentrations of the first and second surfactants. Specifically, according to the exemplary embodiment of the present specification, the molar concentration of the second surfactant may be 0.01 to 1 times the molar concentration of the first surfactant. Specifically, the molar concentration of the second surfactant may be 1/30 to 1 times the molar concentration of the first surfactant.

According to the exemplary embodiment of the present specification, in the step of forming the first solution, the first surfactant and the second surfactant may form micelles according to the concentration ratio. The size or number of cavities of the metal nanoparticles may be adjusted by adjusting the molar ratio of the first and second surfactants. Furthermore, the cavities may be continuously formed to prepare metal nanoparticles including one or more bowl-type particles.

The concentration of the surfactant including the first surfactant and the second surfactant in the first solution may be 0.2 times or more and 5 times or less of the critical micelle concentration (CMC) for the first solvent, specifically, It may be 1 to 5 times.

In the present specification, the critical micelle concentration (CMC) means the lower limit of the concentration at which a surfactant forms a group of molecules or ions (micelles) in a solution.

The most important property of surfactants is that they have a tendency to adsorb on interfaces such as air-liquid interfaces, air-solid interfaces and liquid-solid interfaces. When surfactants are free in the sense that they do not exist in an agglomerated form, they are called monomers or unimers, and when the concentration of unimers increases, they aggregate and the entity of small aggregates, i.e. It forms micelles. This concentration can be referred to as the critical micelle concentration (Critical Micell Concentration).

When the concentration of the surfactant is less than 0.2 times the critical micelle concentration, the concentration of the surfactant adsorbed to the platinum salt may be relatively small. Accordingly, the amount of the surfactant forming the formed core may be reduced overall. On the other hand, when the concentration of the surfactant exceeds 5 times the critical micelle concentration, the concentration of the surfactant is relatively increased, so that the surfactant forming the hollow core and the metal particles not forming the hollow core may be mixed and aggregated.

In the embodiment of the present application, when water is selected as the solvent, the concentration of the surfactant in the solution may be 0.2 times or more and 5 times or less of the critical micelle concentration (CMC) for water, and specifically, 1 It may be greater than or equal to 5 times or less.

According to the exemplary embodiment of the present specification, the size of the metal nanoparticles may be adjusted by adjusting the first surfactant forming the micelle and/or the first and second metal salts surrounding the micelle.

According to the exemplary embodiment of the present specification, the size of the metal nanoparticles may be adjusted by the chain length of the first surfactant forming the micelle. Specifically, when the chain length of the first surfactant is short, the size of the micelles decreases, and accordingly, the size of the metal nanoparticles may decrease.

According to the exemplary embodiment of the present specification, the number of carbon atoms in the chain of the first surfactant may be 15 or less. Specifically, the number of carbon atoms in the chain may be 8 or more and 15 or less. Alternatively, the number of carbon atoms in the chain may be 10 or more and 12 or less.

According to the exemplary embodiment of the present specification, the size of the metal nanoparticles may be adjusted by controlling the type of counter ions of the first surfactant forming micelles. Specifically, the larger the size of the counter ion of the first surfactant, the weaker the binding force with the head of the outer end of the first surfactant may increase the size of the micelles, and accordingly, the size of the metal nanoparticles may increase. .

According to an embodiment of the present specification, when the first surfactant is an anionic surfactant, the first surfactant includes NH ₄ ⁺ , K ⁺ , Na ⁺ or Li ⁺ as a counter ion. Can be.

Specifically, when the counter ion of the first surfactant is NH ₄ ⁺ , the counter ion of the first surfactant is K ⁺ , when the counter ion of the first surfactant is Na ⁺ , the first surfactant The size of the metal nanoparticles may decrease in the order of the case where the counter ion of is Li ⁺ .

According to one embodiment of the disclosure, when the first surfactant is a cationic surfactant, the first surfactant I as a counter ^ion may be one containing a ^-, Br ^- or Cl.

Specifically, when the counter ion of the first surfactant is I ⁻ , the counter ion of the first surfactant is Br ⁻ , and the counter ion of the first surfactant is Cl ⁻ , the metal nanoparticles Can be reduced in size.

According to the exemplary embodiment of the present specification, the size of the metal nanoparticles may be adjusted by adjusting the size of the head of the outer end of the first surfactant forming the micelle. Further, when the size of the head of the first surfactant formed on the outer surface of the micelle is increased, the repulsive force between the heads of the first surfactant increases, so that the micelle may increase, and thus the size of the metal nanoparticles is increased. It can grow.

According to the exemplary embodiment of the present specification, the size of the metal nanoparticle may be determined by a combination of the above-described elements.

The method of manufacturing metal nanoparticles of the present specification includes forming metal nanoparticles having a bowl-shaped first shell part by adding a reducing agent to the first solution. The forming of the metal nanoparticles having the first shell portion may include forming the micelle region to be hollow.

The first shell portion may mean a region of the bowl-type particle containing metal. Specifically, the first shell portion may mean a region of the bowl-type particle excluding the hollow.

The step of forming hollow metal nanoparticles by adding a reducing agent to the solution may be performed at a temperature in the range of 4° C. or more and 90° C. or less, and more specifically 15° C. or more and 80° C. or less.

The step of forming metal nanoparticles by adding a reducing agent to the solution may also be performed at room temperature, specifically at a temperature in the range of 4° C. or more and 35° C. or less, and more specifically 15° C. or more and 28° C. or less. Since the present invention can be manufactured at room temperature, the manufacturing method is simple, so there is an advantage in the process and the cost reduction effect is large.

The step of forming the metal nanoparticles is performed by reacting a solution and a reducing agent for a certain period of time, specifically for 5 to 120 minutes, more specifically for 10 to 90 minutes, and even more specifically for 20 to 60 minutes can do.

The reducing agent is not particularly limited as long as it is a standard reduction -0.23V or less, specifically, -4V or more -0.23V or less, and has a reducing power capable of reducing dissolved metal ions to precipitate as metal particles.

Such a reducing agent may be, for example, at least one selected from the group consisting of NaBH ₄ , NH ₂ NH ₂ , LiAlH ₄ and LiBEt ₃ H. In this case, Et means an ethyl group.

In the case of using a weak reducing agent, the reaction rate is slow, and it is difficult to continuously process the solution, such as the need for subsequent heating, and there may be problems in mass production.In particular, when using ethylene glycol, a kind of weak reducing agent, due to high viscosity There is a problem of low productivity in a continuous process due to a decrease in flow rate.

According to the exemplary embodiment of the present application, in the forming of the metal nanoparticles, a nonionic surfactant may be further added. In one embodiment of the present invention, the nonionic surfactant is specifically polyoxyethylene fatty alcohol ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene castor oil Derivatives, sorbitan ester, glyceryl ester, glycerol monostearate, polyethylene glycol, polypropylene glycol, polypropylene glycol ester, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, aryl alkyl polyether alcohol, polyoxyethylene polyoxy Propylene copolymer, poloxamer, poloxamine, methylcellulose, hydroxycellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylmethylcellulose phthalate, amorphous cellulose, polysaccharides , Starch, starch derivative, hydroxyethyl starch, polyvinyl alcohol, triethanolamine stearate, amine oxide, dextran, glycerol, acacia gum, cholesterol, tragacanth, and polyvinylpyrrolidone selected from the group consisting of Can be.

The nonionic surfactant is adsorbed on the surface of the shell and serves to uniformly disperse the metal nanoparticles formed in the solution. Therefore, the hollow metal particles are prevented from being aggregated or agglomerated and precipitated, and the metal nanoparticles can be formed in a uniform size.

According to the exemplary embodiment of the present application, in the forming of the metal nanoparticles, a stabilizer may be further added. The stabilizer is not particularly limited, for example, disodium phosphate, dipotassium phosphate, disodium citrate, trisodium citrate, aspartic acid, glycine, lysine, and acetic acid. It may include one or two or more selected from the group consisting of.

The method of manufacturing a metal nanoparticle of the present specification includes forming a second shell part made of platinum on the first shell part of the metal nanoparticle by using a second solution in which a platinum salt is added to a second solvent.

The method of manufacturing a metal nanoparticle of the present specification may include forming a second shell part made of platinum on the first shell part of the metal nanoparticle.

In the forming of the second shell part, a second shell part made of platinum may be formed on the first shell part using a second solution in which platinum salt is added to the second solvent. Specifically, the forming of the second shell portion may include forming a platinum ion layer on an outer surface of the first shell portion by adding metal nanoparticles having a first shell portion to a second solution containing a platinum salt and a second solvent; And forming a second shell part made of platinum by adding a reducing agent to the second solution.

The platinum ion layer on the outer surface of the first shell part may be reduced to platinum by the reducing agent to be changed into a second shell part made of platinum.

The reducing agent is not particularly limited as long as it is a standard reduction -0.23V or less, specifically, -4V or more -0.23V or less, and has a reducing power capable of reducing dissolved metal ions to precipitate as metal particles.

Such a reducing agent may be, for example, at least one selected from the group consisting of NaBH ₄ , NH ₂ NH ₂ , LiAlH ₄ and LiBEt ₃ H. In this case, Et means an ethyl group.

The second solvent is not particularly limited as long as it can dissolve the platinum salt, but may include water, and specifically may be water.

The platinum salt is not particularly limited as long as it is ionized in a solution to provide platinum ions. For example, the platinum salt may be a nitrate of platinum, a halide of platinum, a hydroxide of platinum, or a sulfur oxide of platinum.

The molar concentration of the platinum salt may be 1mM or more and 10mM or less.

The method of manufacturing the metal nanoparticles of the present specification may further include removing a surfactant in the metal nanoparticles having the first shell part after the step of forming the metal nanoparticles having the first shell part. The removal method is not particularly limited, and for example, a method of washing with water may be used.

After the bowl-type particles having the second shell portion are formed, a solution including the bowl-type particles may be centrifuged to precipitate particles contained in the solution. Only the separated particles can be recovered after centrifugation. If necessary, a firing process of the metal nanoparticles may be additionally performed.

According to the exemplary embodiment of the present application, bowl-type particles having a uniform size of several nanometers may be manufactured. Not only was it difficult to manufacture bowl-type particles of several nanometers by the conventional method, but it was more difficult to manufacture them in a uniform size.

The method of manufacturing a metal nanoparticle of the present specification may further include, after the step of forming the metal nanoparticle having the first shell part, supporting the metal nanoparticle having the first shell part on a carrier.

The supporting may include coating the carrier with a cationic polymer; And supporting the metal nanoparticles having the first shell portion on a carrier coated with the cationic polymer.

Hereinafter, the present specification will be described in more detail through examples. However, the following examples are for illustrative purposes only and are not intended to limit the present specification.

[Example]

[Comparative Example 1]

Ni(NO ₃ ) ₂ as the first metal salt, K ₂ PtCl ₄ as the second metal salt, ammonium lauryl sulfate (ALS) as the first surfactant, sodium hexanesulfonate as the second surfactant , Trisodium citrate as a stabilizer was added to distilled water to form a solution, followed by stirring for 30 minutes. At this time, the molar ratio of trisodium citrate, K ₂ PtCl ₄ and Ni(NO ₃ ) ₂ was 1:1:3, and ALS was twice the critical micelle concentration (CMC) for water, and sodium The molar concentration of hexanesulfonate was 1.5 times the molar concentration of ALS.

Subsequently, NaBH ₄ as a reducing agent and polyvinyl pyrrolidone (PVP) as a nonionic surfactant were added and reacted for 30 minutes.

Thereafter, centrifugation was performed at 10,000 rpm for 10 minutes to discard the supernatant of the upper layer, and the remaining precipitate was redispersed in distilled water, and the centrifugation process was repeated to prepare bowl-shaped particles.

[Example 1]

The bowl-type particles of Comparative Example 1 were redispersed in water, and 0.5M NaOH was added during stirring to adjust the pH to 10, and then Pt(NH ₃ ) ₄ (NO ₃ ) ₂ (Tetraammineplatinum(II) nitrate) precursor was added to the reactor. After the mixture was stirred for 1 hour, NaBH ₄ as a reducing agent was added to form a Pt skin (second shell part) on the surface of the bowl-type particles.

[Experimental Example 1]

A transmission electron microscope (TEM) of the prepared particles of Comparative Example 1 and Example 1 was measured and shown in FIGS. 6 to 8, respectively.

In FIGS. 6 and 7, the diameter of the bowl-type particles without Pt skin is about 10 nm, and the thickness is about 2 nm to 3 nm. In FIG. 8, the thickness of the bowl-type particles with Pt skin is about 3 nm to 4 nm. Through this, it can be seen that the particle size of the particle of FIG. 8 is increased because the Pt skin is additionally formed, and the thickness of the Pt skin is about 1 nm to 2 nm.

10: electrolyte membrane
20, 21: catalyst layer
40, 41: gas diffusion layer
50: cathode
51: anode
60: stack
70: oxidant supply unit
80: fuel supply
81: fuel tank
82: pump
100: hollow core portion
200: first shell portion
210: platinum
220: transition metal
300: second shell portion
400: carrier

Claims (14)

delete delete delete delete delete delete delete delete delete A first solvent, a platinum salt providing a platinum ion or an atomic group ion including the platinum ion in the first solvent, a transition metal salt providing a transition metal ion or an atomic group ion including the transition metal ion in the first solvent, Forming a first solution comprising a first surfactant for forming micelles in the first solvent, and a second surfactant for forming micelles in the first solvent together with the first surfactant;
Forming metal nanoparticles having a bowl-shaped first shell part by adding a reducing agent to the first solution; And
Forming a second shell portion made of platinum on the first shell portion of the metal nanoparticles by using a second solution in which a platinum salt is added to a second solvent,
The bowl shape is a method of manufacturing metal nanoparticles in which 30% or more of the first shell portion is not continuously formed. The method of claim 10, wherein the second surfactant is a concentration of the first surfactant; Chain length; The size of the outer end; And at least one of the kinds of charges is different. The method of claim 10, wherein the first solvent and the second solvent contain water. The method according to claim 10, wherein the concentration of the surfactant including the first surfactant and the second surfactant in the first solution is 0.2 times or more and 5 times or less of the critical micelle concentration (CMC) for the first solvent. Method for producing phosphorus metal nanoparticles. The method of claim 10, wherein the manufacturing method is performed at room temperature.

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