KR20210101354A - Growth and binding of multicomponent non noble metal nanoparticle on carbon nanofiber membrane by joule heating process and their fabrication method - Google Patents

Abstract

The present invention relates to a multi-component crystalline non-precious metal nanoparticle growth through a Joule heating process, a carbon nanofiber membrane bound to the same, and a method for manufacturing the same. In the present invention, after coating a metal precursor solution on a carbon nanofiber manufactured through a primary stabilization process in which nanofibers randomly spun through an electrospinning device with a spinning solution containing polyacrylonitrile are carried out in an air atmosphere, and a secondary carbonization process carried out in an inert atmosphere, followed by applying a platform capable of large area Joule heating to apply thermal shock, thereby allowing strong growth and binding of non-precious metal nanoparticles having crystallinity such as cobalt-nickel on carbon nanofibers. Therefore, the present invention will be utilized as a core technology for the commercialization of an actual lithium-air battery cathode.

Description

Growth of multi-component crystalline non-precious metal nanoparticles through Joule heating process and carbon nanofiber membrane binding the same and manufacturing method thereof

An embodiment of the present invention relates to a multi-component crystalline non-noble metal nanoparticle growth through a Joule heating process, a carbon nanofiber membrane bound thereto, and a method for manufacturing the same. More specifically, a large-area Joule heating is performed by dispersing a solution in which a non-noble metal salt is dissolved on a carbon nanofiber membrane made by dissolving polyacrylonitrile in a solvent and electrospinning a membrane through a primary stabilization process and a secondary carbonization process. Through this possible platform, we provide a membrane in which nanoparticle catalysts having a diameter of several to tens of nanometers are grown and strongly bound, and a method for manufacturing the same, and catalyst-current in which catalysts that can be used independently in energy storage systems are strongly bound. It is possible to provide a current collector-integrated carbon material-based electrode and a method for manufacturing the same.

As interest in clean energy sources and energy storage technology is rapidly increasing due to environmental pollution, electric vehicle technology that uses batteries, not gasoline, which generates various exhaust gases, is receiving great attention as an eco-friendly energy technology. In particular, recently, electric vehicles based on lithium ion batteries have been commercialized, but due to the low energy density of current lithium ion batteries, long-distance driving (more than 400 km) is difficult. Accordingly, a lithium-air battery system having an energy density 10 times higher than that of a conventional lithium ion secondary battery (at the same level as that of gasoline) is being highlighted as an alternative. Lithium-air batteries have a mechanism to store energy from air components (especially oxygen) present in the atmosphere, so lithium, which is the negative electrode, is oxidized to generate lithium ions, and at the same time, the oxygen gas introduced through the positive electrode material is converted into lithium ions and Li ₂ It has a system in which an electrochemical reaction that forms (discharges) and decomposes (charges) an oxide in the form of _{O 2 occurs repeatedly.}

However, the lithium-air battery of the current stage has significantly lower lifespan characteristics than the conventional lithium ion secondary battery, and the actual usable energy density remains at a very low level compared to the theoretical value. More specifically, non-conductive lithium oxide, which is a discharge by-product generated during battery operation, is not decomposed during charging and is laminated on the surface of the positive electrode to cause an overvoltage problem, which leads to a problem in that reversible charging and discharging and the efficiency thereof are deteriorated. In addition, when a carbon-based cathode having a high energy density is used, lithium oxide reacts with surrounding carbon elements _{to form lithium carbonate (Li 2} CO ₃ ), which causes an overvoltage to be greater. Therefore, it is urgent to develop a lithium-air battery system that can effectively cause a reversible charge-discharge reaction and has a high level of energy density.

In order to solve the problems of the low capacity and irreversible charge/discharge reaction and overvoltage of the current lithium-air battery, there is a lot of research into the development of carbon-based cathode materials with catalysts that can smoothly generate and decompose _{Li 2} O ₂ and Li ₂ CO ₃ Studies are being focused. In the current state of the art, in order to overcome the problem of lowering battery efficiency, an air electrode in which a noble metal material such as platinum (Pt), iridium (Ir), and ruthenium (Ru) and a noble metal-based compound are bound is used. However, when a noble metal material is used as a catalyst, high cost is required due to the rarity of the noble metal, and there is a very big limitation in manufacturing a large-area electrode for commercialization and high capacity. To replace this, recently, non-noble metal particles are produced by using a nano-template such as cellulose and apoferritin to form nanoparticles (No. 10-20190018851) or a high-temperature heat treatment of a carbon structure containing a non-noble metal salt. Through the method of grain growth (Carbon 2016, 329-336) or the method of synthesizing non-noble metal particles through hydrothermal synthesis proceeding in a liquid phase under a high-temperature and high-pressure environment (No. 10-20130056852), an air electrode based on non-noble metal particles was produced. A lot of research has been done to develop it. In the case of using nanotemplates, nanoparticles can be grown relatively uniformly, but there is a limitation in that the manufacturing cost increases due to the high cost of nanosized templates. Not only does it take time, but when the non-noble metal particles of a multi-component system are formed, there is a limitation in that the characteristics of the catalyst are deteriorated due to phase separation. In addition, when several non-noble metal salts are grown through hydrothermal synthesis, phase separation of the metal particles is caused, which shows a limitation in that catalyst activity cannot be caused through the alloying effect of multi-component non-noble metal nanoparticles. In addition, when catalyst particles are formed on the electrode through the conventional technology, the charge/discharge performance of the electrode is deteriorated due to the problem of desorption of the catalyst, and the catalyst particles in the electrolyte are dissociated to corrode the electrolyte.

Therefore, in order to overcome the above limitations, it is excellently applied as a cathode through a synthesis technology that can cause the alloying effect of a multi-component catalyst by growing non-noble metal nanoparticles having a low cost in a crystalline form without phase separation, and a low cost and simple manufacturing process. There is a need for a manufacturing technology capable of strongly binding and growing multi-component non-precious metal nanoalloy particles on possible carbon nanofiber membranes. Furthermore, by applying this to a lithium-air battery system, a catalyst-current collector integrated carbon nanofiber membrane in which catalyst nanoalloy particles are strongly bound, which can provide high energy density similar to the theoretical energy density and excellent life characteristics, An air electrode and its manufacturing technology are desperately needed.

The present invention includes non-noble metal nano-catalyst alloy particles having a low cost, including multi-component crystalline non-noble metal nano-particle growth and carbon nano-fiber membrane synthesis technology through a Joule heating process, on a carbon nano-fiber membrane for a short process time. And it provides a catalyst-current collector integrated carbon nanofiber membrane cathode and manufacturing technology thereof. The carbon nanofiber membrane proposed in the present invention is synthesized using electrospinning equipment including a rotatable conductive current collector and a high voltage generator, and the rotation speed of the conductive current collector, the voltage of the high voltage generator, and the electrospinning nozzle discharged from the electrospinning nozzle It includes technology that can control the type, thickness, density, etc. of nanofibers by controlling variables such as the discharge speed of the liquid used. The file heating process proposed in the present invention provides a platform technology that enables stable current distribution even in a sample size that is 50 times wider than the conventional file heating sample size (1 cm × 0.2 cm), and is specialized for non-precious metals generated at low temperature. It is very different from the conventional small area Joule heating in terms of the process. In addition, the multi-component crystalline non-noble metal nanoparticles growth and the carbon nanofiber membrane bound thereto of the present invention grow and carbonize the multi-component crystalline non-noble metal nanoparticles through a short process time of several hundred ms. It provides a technology in which the catalyst and the current collector are integrated as an air electrode without desorption of the catalyst because it can be bound on the fiber membrane.

The fact that it is difficult to reduce the production cost due to the dispersibility, uniformity, or high cost of raw materials used as catalysts of conventional nanoparticle catalysts, and nanoparticle growth through the conventional Zul heating process and the membrane binding it are used as electrodes. It solves the limitation that the area is small to use and enables a large-area Joule heating process, so it has low-cost non-noble metals in a multi-component system, and shows improved oxygen generation/reduction reactivity compared to existing mono-element non-noble metal catalysts, and immediately after manufacturing A positive electrode capable of providing a conductive carbon nanofiber membrane to which nanoparticles are bound as an electrode and a manufacturing method thereof can be provided, and can be used as a self-independent cathode of an actual lithium-air battery system to realize a high-capacity/long-life lithium-air battery system It can be used as a material.

In particular, carbon nanofiber membranes based on the existing electrospinning technology have been used as next-generation cathode materials such as lithium-air batteries. have Accordingly, a process of heating a mixture of a metal salt and an amine to obtain a reaction solution and heating it to obtain a nanoparticle slurry has been introduced. It has the limitation that it cannot be expected. (Korean Patent Publication No. 10-20130056852). In addition, nanoparticle formation and dispersion technology using a porous protein molecule template that helps in the formation of nanoparticles has also been introduced, but the process has limitations in that the unit cost is high and it is difficult to be firmly fixed when binding to the structure later. (Korean Patent Publication 10-20190018851). On the other hand, the multi-component non-noble metal nano-particle catalyst manufacturing technology using a Zul heating platform applicable to a large-area carbon nano-fiber membrane proposed in this technology uses a non-noble metal-based material and uses a non-noble metal-based material to convert crystalline alloy-type nanoparticles into carbon nanoparticles. It can grow and bind strongly on the fiber membrane, and the size, crystallinity, and dispersion density of nanoparticles can be controlled according to the concentration, current, voltage, process time and frequency of the precursor solution. By providing a method capable of producing a size, it is possible to overcome the limitations of the existing nanoparticle catalyst manufacturing process and dispersion and binding methods.

Furthermore, it is a multi-component crystalline non-precious metal nano through the Zul heating process, which has characteristics that are different from the existing non-uniform particle size, high production cost, and methods that were difficult to directly apply an efficient structure as an electrode. By using particle growth and carbon nanofiber membrane bound thereto as the cathode of lithium-air battery, it induces improved oxygen generation/reduction reaction and reversible generation/decomposition reaction of charging/discharging products, so that high-capacity and long-life lithium-air battery in actual atmosphere system can be provided.

A method of coating a carbon nanofiber membrane prepared through an electrospinning process and a two-step heat treatment process with a conventionally known composite spinning solution containing polyacrylonitrile and a solvent is impregnated in a solution containing a non-noble metal precursor. Including a platform that allows the membrane to apply a Joule heating process with a maximum area of 50 times increased compared to the existing sample size, and a short-time thermal shock is applied to achieve even dispersion, uniform size, and strong binding force with the membrane We provide a platform and carbon nanofiber membrane characterized in that it is possible to produce a sample of a standard that can be used as a self-independent electrode and an improved oxygen generation/reduction reaction catalytic effect by manufacturing a nanoparticle catalyst having crystallinity with

According to one side, the carbon nanofiber membrane is electrospinning by dissolving polyacrylonitrile, which is a synthetic semi-crystalline organic polymer resin having a linear chemical formula, in a solvent and applying a voltage of 10 to 20 kV, and then in the range of 200 to 300 ° C. 6 carbon atoms that provide structural stability connected to a ladder structure between neighboring carbon atoms through the primary heat treatment process included in It may be characterized in that it provides a conjugated structure constituting a planar ring structure of a regular hexagonal shape.

According to another aspect, the membrane has a shape in which a plurality of carbon nanofibers having a one-dimensional structure are randomly stacked and exhibits good electron mobility, and the thickness of the membrane is in the range of 5 μm to 100 μm, , the area of the membrane may be characterized in that it is included in the range of ^{1 cm 2} to 900 cm ²

According to one side, the nanoparticles are coated by impregnating the carbon nanofiber membrane in a solution containing the precursors of multi-component non-noble metal elements in a specific ratio, and being included in the range of 60 ~ 120 ℃ in a vacuum atmosphere depending on the solvent used. The solvent is dried through heat treatment, the sample is fixed using silver paste on a glass plate, compressed using copper foil, and the solvent contained in the silver paste is subjected to heat treatment in the range of 100 to 140 ° C in a vacuum atmosphere. and polymer are removed, and a current corresponding to 0.5 to 4 A is applied for a period of time ranging from 1 to 4000 ms in a vacuum atmosphere ranging from 10 to 30 mTorr, and thermal shock is applied to the sample to ensure even dispersion, uniform size, and It may be characterized in that the nanoparticle catalyst having crystallinity with strong binding force is prepared.

According to another aspect, the diameter of each of the plurality of nanoparticles can be adjusted in a size range of 5 nm to 100 nm, and may be characterized in that it represents a composition ratio related to the concentration of non-noble metal ions contained in the precursor solution. .

According to another aspect, the diameter of the nanoparticles increases as the heat treatment time increases, and may be characterized in that it exhibits a tendency to decrease as the number of heat treatments increases.

A method for manufacturing a large-area carbon nanofiber membrane to which nanoparticles are bound, the method comprising: (a) preparing a precursor solution containing multi-component non-noble metal ions; (b) coating the prepared precursor solution on a carbon nanofiber membrane; (c) heat-treating within a temperature range of 60 ~ 120 ℃ in a vacuum atmosphere; (d) placing the sample on a glass plate partially coated with silver paste; (e) applying silver paste to both ends of the sample and compressing it with copper foil; (f) heat-treating the sample within a temperature range of 100 to 140° C. in a vacuum atmosphere; (g) applying a current corresponding to 0.5 to 4 A to the sample in a vacuum atmosphere for a time in the range of 1 to 4000 ms to apply a thermal shock to the sample; (h) provides a method for producing a multi-component crystalline non-noble metal nanoparticle growth and binding carbon nanofiber membrane comprising the step of separating the sample from the glass plate.

According to one side, in step (a), the solvent is formic acid, acetic acid, phosphoric acid, sulfuric acid, m-cresol, tifluoroacetandhydride/dichloromethane, Water, N-methylmorpholine N-oxide, chloroform, tetrahydrofuran and aliphatic ketone group methyl isobutyl ketone, methyl ethyl ketone, aliphatic hydroxyl group m-butyl alcohol, isobutyl alcohol, isopropyl alcohol, methyl alcohol, Ethanol, hexane as an aliphatic compound, tetrachloroethylene, acetone, propylene glycol, diethylene glycol, ethylene glycol as a glycol group, trichloroethylene, dichloromethane as a halogen compound group, toluene, xylene, aliphatic ring as a group of aromatic compounds Cyclohexanone as a compound group, n-butyl acetate as an ester group with cyclohexane, ethyl acetate as an ester group, butyl cellosalb as an aliphatic ether group, 2-ethoxyethanol acetate, 2-ethoxyethanol, dimethylformamide as an amide, dimethyl It may be characterized in that it comprises one or more solvents selected from the group consisting of acetamide and mixtures thereof.

According to another aspect, in the step (b), the carbon nanofiber membrane is _{subjected to an O 2} plasma process with an intensity of 10 W to 200 W to increase the defect elements on the surface to strengthen the bonding force with the solution-phase precursors. can be done with

According to another aspect, in step (b), the precursor contained in the solution is adjusted to a concentration in the range of 0.0001 M to 1 M, and the carbon nanofiber membrane is immersed in the solution for 1 second to 24 hours to apply the precursor to the membrane surface. It may be characterized in that it is uniformly dispersed in

According to another aspect, in step (c), it is a process for evaporating the solvent of the precursor solution, and it may be characterized in that the final dispersion degree and the ion reduction ratio of the precursor are adjusted by selecting the solvent and controlling the temperature.

According to another aspect, the size of the glass plate to be used in step (d) is larger than the size of the membrane to be used, and the silver paste serves as a current collector through which current flows during the Joule heating process. It is uniformly applied to both ends of the glass plate to be connected, and the application range is limited to the outside of the area to be used as the sample in the membrane to define the sample area among the membrane specifications placed on the glass, and it can be characterized by defining the maximum amount of power to be applied to the unit area. have.

According to another aspect, in step (e), the silver paste is uniformly applied to both ends of the membrane placed on the glass plate coated with silver paste so that it can be connected to the silver paste area applied to the glass plate, and the copper It can be characterized in that the foil is raised and compressed uniformly with a flat plate so that the silver paste can be uniformly permeated into the pores of the membrane, thereby securing the path of current and allowing the current to flow evenly throughout the sample.

According to another aspect, in step (f), the platform is adjusted in a vacuum atmosphere within a temperature range of 100 to 140° C. and a time range of 1 to 24 hours to appropriately control the degree of removal of the solvent and polymer from the silver paste. Therefore, it is necessary to control the adhesion to the membrane and the stability of the sample during subsequent processes. Silver paste is made by dispersing silver particles with a diameter of several hundred nanometers to several micrometers in a polar solvent such as α-Terpineol, IPA, ethanol, and water. makes

According to another aspect, in the step (g), the large-area Joule heating platform that has undergone the step (f) is supplied with strong electric power in a vacuum atmosphere to use thermal energy generated by current flow obstruction on the carbon nanofiber membrane. A heat treatment process in which non-noble metal ions that existed in an ionic state in the It is characterized in that the size and dispersion of nanoparticles and the electrical conductivity of the sample are controlled by applying a thermal shock to the platform by installing a Zul heating device and controlling the current corresponding to 0.5 to 4 A within the range of 1 to 4000 ms in a vacuum atmosphere. can be done with

As another solution of the present invention, in order to control the appropriate conductivity during the Joule heating process of the carbon nanofiber membrane used in step (b), a trace amount of carbon having a level smaller than the diameter size of the electrospun nanofiber It includes a method of complexing with nanotubes, and forms a hierarchical structure due to primary pores by carbon nanofibers and secondary pores derived from other materials to control the pore shape, and to measure the resistance and electron movement path characteristics of electrodes. It may be characterized in that it is adjusted.

In particular, in a lithium-air battery consisting of a lithium metal cathode, a separator, an air anode, and an air diffusion layer for application to eco-friendly energy technology, the orthogonal carbon nanofiber material developed in the present invention is used as a positive electrode to form an air anode suitable for an air battery. It may be characterized by designing the structure.

The present invention is not utilized only in the field of eco-friendly energy, and can be characterized in that it can be applied to any field requiring conductivity and catalytic effect as needed.

An object of the present invention is to provide a large-area carbon nanofiber membrane in which non-noble metal multi-component nanoparticles are grown in a short time and in a simple process, and to which a nanoparticle catalyst that can easily control the size and dispersion is bound. It is possible to manufacture at low cost by binding a nanoparticle catalyst having a multi-component non-noble metal-based material to replace the noble metal-based catalysts that have been used a lot in the past by adjusting the desired concentration, dispersion, and size, and forming a carbon nanostructure. Since the fiber can be used as a self-independent electrode that does not require a current collector, it is possible to provide a catalyst combination that meets the detailed characteristics required in most industries where catalysts are used without additional processing. For example, for the development of catalysts for oxygen generation/reduction reactions, non-noble metal-based catalysts known to promote oxygen evolution and oxygen reduction reactions, respectively, are prepared with specific compositions, thereby making a bidirectional catalyst with increased reversibility. In addition, this technology capable of producing a large area without being limited to the area of a carbon thermal shock sample through the conventional Joule heating process is very suitable as a commercialization technology.

The present invention is expected to be highly likely to be utilized as a positive electrode material suitable for overvoltage improvement of lithium-air batteries among many fields. Carbon material is light in weight and has high thermal stability, so it is suitable for use in the energy field. It is believed that it will be of great help in pioneering a new research field in the field of catalysts because it is possible to produce samples of possible specifications. In addition to these energy applications, it is expected to be applied to gas sensors and carbon dioxide reduction studies that require catalytic performance.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as a part of the detailed description to help the understanding of the present invention, provide embodiments of the present invention, and together with the detailed description, explain the technical spirit of the present invention.
1 is a schematic diagram of a platform for large-area Joule heating for binding a non-noble metal multi-component crystalline nanoparticle catalyst according to an embodiment of the present invention
2 is a carbon obtained by strongly binding a multi-component crystalline nanoparticle catalyst using a heat treatment process using a platform capable of large-area Joule heating of a precursor solution in which multi-component non-noble metal ions and solvents are mixed according to an embodiment of the present invention; It is a flowchart related to a method for manufacturing a nanofiber membrane.
3 is a carbon nanofiber in which a multi-component nano-particle catalyst is strongly bound using a heat treatment process using a platform capable of large-area Joule heating of a precursor solution in which multi-component non-noble metal ions and solvents are mixed according to an embodiment of the present invention; (a) a low magnification scanning electron microscope image and (b) a high magnification scanning electron microscope image of the membrane are shown.
4 shows a transmission electron microscope image of a carbon nanofiber membrane in which a multi-component crystalline nanoparticle catalyst is strongly bound using a heat treatment process using a platform capable of large-area Joule heating according to an embodiment of the present invention.
5 is a carbon nanofiber in which a multi-component nano-particle catalyst is strongly bound using a heat treatment process using a platform capable of large-area Joule heating of a precursor solution in which multi-component non-noble metal ions and solvents are mixed according to an embodiment of the present invention; Transmission electron microscope EDS image of the membrane.
6 is a nanoparticle synthesized by a liquid phase process through high temperature heat treatment of the same non-noble metal nanoparticle element according to a comparative example of the present invention (Reference: "Size and Composition Control of CoNi Nanoparticles and Their Conversion into Phosphides", Chem. Mater. 2017, 29, 7, 2739-2747) shows the transmission electron microscope EDS image.
7 is an actual example showing that heat is uniformly generated over the entire sample area by applying a current to a large-area Joule heating platform according to an embodiment of the present invention and applying a thermal shock to a large-area (2 cm × 5 cm) carbon nanofiber membrane. It is an image.

The present invention can apply various transformations and can have various embodiments. Hereinafter, specific embodiments will be described in detail based on the accompanying drawings.

In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first, second, etc. may be used to describe various elements, but the elements are not limited by the terms, and the terms are used only for the purpose of distinguishing one element from other elements. used

Hereinafter, a carbon nanofiber membrane in which a multi-component nanoparticle catalyst is strongly bound through a heat treatment process using a platform capable of large-area Joule heating of a precursor solution in which multi-component non-noble metal ions and solvents are mixed, and a method for manufacturing the same It will be described in detail with reference to the drawings.

An embodiment of the present invention is carbon made through a primary stabilization process in which a spinning solution containing polyacrylonitrile is randomly spun through an electrospinning device in an air atmosphere, and a secondary carbonization process in an inert atmosphere. It is characterized in that nanofibers are coated with a metal precursor solution and then thermal shock is applied to strongly grow and bind non-noble metal nanoparticles having crystallinity such as cobalt-nickel on carbon nanofibers. Compared to the existing Joule heating sample size (1 cm × 0.2 cm), it has a platform that enables stable current distribution even with a significantly wider sample size, very differentiated In addition, it has excellent properties as an electrode such as a lithium-air battery by growing multi-component crystalline non-noble metal nanoparticles through a short process time of several hundred ms and binding on the carbonized fiber membrane at the same time. .

Looking at the existing nanoparticle manufacturing technology trends, studies have been attempted in the method of manufacturing nanoparticles using a solution process. However, in the case of manufacturing by a solution process, the size of the particles increased or showed a non-uniform distribution during a long heat treatment process, and phase separation occurred when multi-components were included. This is difficult to name as binary crystalline nanoparticles, and has shown limitations in that it shows only the effect of the interface, not the new effect due to the alloying effect. In addition, the method of synthesizing nanoparticles using a template shows a uniform nanoparticle size and relatively even dispersion, but the use of templates such as apoferritin and the high cost of these protein structure materials increase the manufacturing cost. limitations have been shown. To improve this, a Joule heating method for producing nanoparticles through ultra-short time heat treatment has been recently studied, but the sample size is very small (0.2 cm × 1 cm), so it is limited to self-independent practical use in a wide field.

Therefore, if the size of the prepared sample is at a level suitable for practical use, and nanoparticles having a uniform dispersion and size strongly bound to the carbon nanofiber membrane are synthesized, a rapid oxygen generation/reduction reaction catalyst and next-generation energy with excellent reproducibility Carbon nanofibers that can be applied independently and immediately as a catalyst for the cathode of a lithium-air battery, a system, will be developed.

In the present invention, 6 carbon atoms form a planar ring structure and dropwise binding of multi-component non-precious metal nanoparticles on a one-dimensional nanofiber structure having excellent electrical conductivity properties, which has high electron mobility and a multi-component system Growth and strong binding of nanoparticle catalysts with diameters of several to tens of nanometers through a platform capable of large-area Joule heating with improved oxygen generation/reduction reaction catalytic performance compared to single-component non-noble metal catalysts due to the non-noble metal alloying effect of A membrane and a method for manufacturing the same are provided. The nanoparticle catalyst synthesis method through the large-area Joule heating provided uniform nanoparticle size and dispersion compared to conventional nanoparticle synthesis methods. In order to produce a nanoparticle catalyst through large-area Joule heating with the above characteristics, an efficient and easy platform capable of synthesizing a large area is presented, enabling the use of a self-independent electrode in which nanoparticles are uniformly and strongly bound even in a very short process time. It is characterized in that it is easy to implement carbon nanofibers.

1 is a glass plate 100 coated with silver paste according to an embodiment of the present invention, a carbon nanofiber membrane 101 dried by impregnating in a solvent including a non-noble metal precursor attached on the glass pot, and silver paste on both ends. It is a schematic diagram of the coated sample 102, and a large-area Joule heating platform 103 in which copper foils are pressed on both ends.

At this time, it is preferable that the application of the silver paste is uniform. In the subsequent process, it is preferable to apply uniformly because it is to secure electron transfer paths at both ends of the dry carbon nanofiber membrane by impregnating it in a solvent containing a non-noble metal precursor. In addition, since the area of the unpainted glass plate becomes an area that can be actually used later, it is preferable to set it slightly larger than the target area. Additionally, it is possible to manufacture highly reproducible samples on the same area by using a masking template when setting a target area for mass production.

In addition, in order to uniformly disperse the non-noble metal ions, the ions should not cause a sediment-forming reaction. For this purpose, formic acid, acetic acid, phosphoric acid, sulfuric acid, m-cresol, tifluoroacetandhydride/dichloromethane, water, N-methylmorpholine N-oxide , chloroform, tetrahydrofuran and aliphatic ketone group methyl isobutyl ketone, methyl ethyl ketone, aliphatic hydroxyl group m-butyl alcohol, isobutyl alcohol, isopropyl alcohol, methyl alcohol, ethanol, aliphatic compound hexane, tetrachloroethylene, Acetone, propylene glycol, diethylene glycol, ethylene glycol, as a group of glycols, trichloroethylene, dichloromethane as a group of halogen compounds, toluene, xylene as a group of aromatic compounds, cyclohexanone as a group of aliphatic compounds, chlorohexane and esters n-butyl acetate, ethyl acetate, aliphatic ether, butyl cellosalb, acetic acid 2-ethoxyethanol, 2-ethoxyethanol, amide selected from the group consisting of dimethylformamide, dimethylacetamide, and mixtures thereof It is important to use a solvent to prevent precipitation of ions and to disperse them uniformly in the solution.

2 is a carbon obtained by strongly binding a multi-component crystalline nanoparticle catalyst using a heat treatment process using a platform capable of large-area Joule heating of a precursor solution in which multi-component non-noble metal ions and solvents are mixed according to an embodiment of the present invention; It shows a flow chart for a method for manufacturing a nanofiber membrane. As shown in the flowchart of FIG. 2 , the method for producing multi-component crystalline non-noble metal nanoparticles and binding them to a large-area carbon nanofiber membrane is a method for manufacturing a large-area carbon nanofiber membrane to which nanoparticles are bound, (a ) preparing a precursor solution containing multi-component non-noble metal ions; (b) coating the prepared precursor solution on a carbon nanofiber membrane; (c) heat-treating within a temperature range of 60 ~ 120 ℃ in a vacuum atmosphere; (d) placing the sample on a glass plate partially coated with silver paste; (e) applying silver paste to both ends of the sample and compressing it with copper foil; (f) heat-treating the sample within a temperature range of 100 to 140° C. in a vacuum atmosphere; (g) applying a current corresponding to 0.5 to 4 A to the sample in a vacuum atmosphere for a time in the range of 1 to 4000 ms to apply a thermal shock to the sample; (h) separating the sample from the glass plate. Hereinafter, each of the above steps will be described in more detail.

First, a step (a) of preparing a precursor solution containing multi-component non-noble metal ions will be described. The source of the non-noble metal ion is in the form of a metal salt including chloride (-Cl), iodide (-I), and nitrate (-NO3) or a hydrate (·H ₂ O) of the salts, and is dissolved in the following solvents It includes all types of substances including target metal ions that can be ionized.

Sources of the non-noble metal ions selected above are N,N'-dimethylformamide (N,N'-dimethylformamide), dimethylsulfoxide, N,N'-dimethylacetamide (N,N'dimethylacetamide), N -Metal ions are ionized by completely dissolving the ion supply materials in the solvent using compatible solvents such as N-thylpyrrolidone, distilled water, and ethanol.

In order to prepare a multi-component precursor solution, the total concentration of the precursor is preferably in the range of about 0.005-0.1 M. When composing a multi-component precursor solution, the composition of nanoparticles generated after execution of the final process can be adjusted according to the type and composition of precursor ions. The agitation of the solution containing the precursor and the solvent is performed at room temperature, and sufficiently stirred so that the material containing the metal ion is completely dissolved in the solvent.

Second, using the precursor solution prepared above, the steps (b), (c), (d), Look at (e) and (f). First, the precursor solution prepared in step (a) is transferred to a Petri dish of an appropriate width, and then the carbon nanofiber membrane cut to an appropriate size is _{subjected to O 2} Plasma process with an intensity of 10 W to 200 W Through the process, the defect elements on the surface are increased to strengthen the bonding force with the solution precursors. After _{that, the carbon nanofiber membrane subjected to the O 2} plasma process is put in a Petri dish containing the precursor solution to be completely immersed in the solution, and then the precursor is uniformly dispersed and coated on the membrane surface by immersion for 1 second to 24 hours. Thereafter, the solvent of the precursor solution is evaporated by heat treatment within a temperature range of 60 to 120° C. in a vacuum atmosphere. In the process, depending on the solvent, dry completely for 30 minutes to 24 hours or longer if necessary. At this time, according to the solvent used, it is possible to control the nanoparticle dispersion and the reduction ratio of metal ions after the final process. For the glass plate that serves as the structure of the platform for large-area Joule heating, a glass plate that is not modified at high temperatures should be used, and unless the purpose is different, it is not decomposed and damaged at 2000 °C or higher, so any type of glass plate that does not affect the carbon nanofiber membrane including the use of supports. The size of the glass plate support is larger than the size of the membrane to be used, and the silver paste is to play the role of a current collector through which current flows during the Joule heating process. The range is limited outside the area to be used as a sample in the membrane based on the center of the glass plate. Both ends of the carbon nanofiber membrane subjected to step (c) are fixed on the glass plate coated with the silver paste. After that, the silver paste is uniformly applied on both ends so that it can be connected to the silver paste area applied to the glass plate. The purpose is to ensure that the current can flow evenly throughout the sample by allowing it to permeate well to secure the current path. In this case, the copper foil may be maintained or not maintained when a current flows in a subsequent process, and includes using any type of foil and current collector metal having conductivity. 100 ~ 140 of the sample in a vacuum atmosphere The purpose is to increase the degree of adhesion with the membrane and the stability of the sample during subsequent processes by appropriately controlling the degree of removal of the solvent and polymer in the silver paste by controlling the temperature range of ℃ and the time range of 1 to 24 hours. . Silver paste is made by dispersing silver particles with a diameter of several hundred nanometers to several micrometers in a polar solvent such as α-Terpineol, IPA, ethanol, and water. , to reduce the contact resistance between the current collector and the carbon nanofiber membrane by removing the polymer and drying the solvent in the heat treatment process. By performing a series of the above processes, it is possible to manufacture a platform capable of large-area Joule heating.

Next, a step (g) of applying a thermal shock to the sample by applying an electric current to the sample in a vacuum atmosphere for a short time will be described. A step of applying a thermal shock to the sample by applying a current corresponding to 0.5 to 4 A in a vacuum atmosphere for a period of time in the range of 1 to 4000 ms. In a reducing atmosphere, diffusion and The reduction process occurs instantaneously, and crystal nucleation is induced at the defect point on the surface of the carbon nanofiber. When the heat generated by thermal shock is sufficiently generated, light is generated from the carbon nanofiber membrane, and the lower the temperature, the darker red, and the higher the temperature, the closer to white light. The intensity of the thermal shock showed a characteristic proportional to the amount of power applied to the carbon nanofibers of a unit area, and it is preferable to apply appropriate voltage and current values according to the resistance of the carbon nanofiber membrane. By controlling the amount of applied power, non-noble metal nanoparticles generated at low temperatures and nanoparticles generated at high temperatures can be grown. It is preferable to adjust the power application time within the range of 1 to 4000 ms according to the target dispersion degree and the size of the particles, but if necessary, it includes proceeding longer than that. In addition, it is possible to control the size of nanoparticles by repeating the thermal shock process at a specific time interval ranging from 10 to 4000 ms.

Finally, look at the step (g) of separating the sample from the large-area Joule heating platform. Both ends of the carbon nanofiber membrane area to which the Silper Paste is not applied are removed and separated by pressing them at once using a wide blade in the cross-sectional view.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. Examples and comparative examples are only for illustrating the present invention, and the present invention is not limited to the following examples, and it is apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that changes and modifications fall within the scope of the appended claims.

Example 1: Growth of two-component crystalline non-noble metal nanoparticles through Zul heating process and carbon nanofiber membrane binding the same

3(a) and 3(b) are low magnification scanning electron microscopes of a carbon nanofiber membrane in which a bicomponent nickel-cobalt crystalline alloy nanoparticle catalyst prepared through steps (a) to (h) is strongly bound. Images and high-magnification scanning electron microscopy images are shown. It is characterized in that nickel-cobalt nanoparticles are uniformly dispersed and bound on carbon nanofibers having a diameter of 600 nm to 1 μm, and the size of the nanoparticles is very uniformly generated and bound.

4 is a transmission electron microscope image of a carbon nanofiber membrane in which a multi-component crystalline nanoparticle catalyst is strongly bound using a heat treatment process using a platform capable of large-area Joule heating according to an embodiment of the present invention, the size of which is 10 nm or less. It can be confirmed that the multi-component non-noble metal is formed in a crystalline phase.

5 is a transmission electron microscope EDS image of the carbon nanofiber membrane to which the nanoparticle catalyst is strongly bound through the above example, and it is seen that the element distribution of Co and Ni is at the same position, and nanoalloy particles are formed without phase separation. can confirm. This is very different from the phase separation phenomenon that occurs when reducing metal salts of the existing multi-component system, and it is expected that the catalytic synergistic effect characteristics of the crystalline alloy particles synthesized in the above example can be maximized.

7(a) and 7(b) show a large-area (2 cm × 5 cm) carbon nanofiber by applying a current of 1A to a platform capable of large-area Joule heating manufactured through the process up to step (f) above. A real image showing that heat is uniformly generated over the entire sample area by applying a thermal shock to the membrane is shown. It can be seen that stable current distribution is achieved even in the sample size, which is 50 times wider than the existing Joule heating sample size (1 cm × 0.2 cm).

Comparative Example 1: Comparison of composition distribution of nanoparticles containing nickel-cobalt prepared by applying this example with a case of synthesizing nanoparticles by other manufacturing processes

In Comparative Example 1, the same non-noble metal nanoparticle elements as in Example 1 were synthesized, but non-metallic nanoparticles synthesized by a liquid phase process through high-temperature heat treatment (Reference: "Size and Composition Control of CoNi Nanoparticles and Their Conversion into Phosphides", Chem. Mater. 2017, 29, 7, 2739-2747) synthesis.

FIG. 6 shows that nickel and cobalt are separated and formed into the center and surface of the nanoparticles. This is in stark contrast to the nickel-cobalt shown in FIG. 5, which is uniformly distributed throughout the nanoparticles and takes the form of a nano-sized alloy. Through this, in Example 1, it can be confirmed that the diffusion distance of each constituent atom is limited by a short heat treatment process within 1 ms to 4000 ms, so that nanoalloy particles in a high entropy state can be produced.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments described in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and are not limited to these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (12)

It includes preparing a precursor solution containing multi-component non-noble metal ions,
The precursor solution prepared above is coated on a carbon nanofiber membrane, subjected to dry heat treatment, and fixed on a glass plate partially coated with silver paste, silver paste is applied to both ends, and compressed with copper foil to undergo dry heat treatment to perform large-area Joule heating. including how to make the platform possible;
The prepared platform was made by applying a thermal shock to the sample by applying an appropriate current for a suitable time in a vacuum atmosphere,
Strong growth and binding of crystalline non-precious metal nanoparticles
characterized by,
A multi-component crystalline non-noble metal nanoparticle growth and a carbon nanofiber membrane bound therewith, and a method for manufacturing the same. According to claim 1,
Carbon nanofibers made through a primary stabilization process in which a spinning solution containing polyacrylonitrile is randomly spun through an electrospinning device in an air atmosphere and a secondary carbonization process in an inert atmosphere are used as the matrix to do
Coating the non-noble metal precursor solution by impregnating carbon nanofibers characterized in
Strong growth and binding of crystalline non-noble metal nanoparticles such as cobalt-nickel on carbon nanofibers by applying thermal shock to the membrane, characterized in that
A multi-component crystalline non-noble metal nanoparticle growth and a carbon nanofiber membrane binding the same. According to claim 1,
The diameter of each of the nanoparticles bound on the carbon nanofiber is adjustable in a size range of 5 nm to 100 nm
Representing the composition ratio related to the concentration of non-noble metal ions contained in the precursor solution characterized by
Binding of crystalline nanoparticles with uniform distribution of components on a single particle, characterized by
A multi-component crystalline non-noble metal nanoparticle growth and a carbon nanofiber membrane binding the same. According to claim 1,
The area of the membrane that can be manufactured using the platform is 1 cm ² to 900 cm ^{2 What} is included in the range
A multi-component crystalline non-noble metal nanoparticle growth and a carbon nanofiber membrane binding the same. (a) preparing a precursor solution containing multi-component non-noble metal ions;
(b) coating the prepared precursor solution on a carbon nanofiber membrane;
(c) heat-treating within a temperature range of 60 ~ 120 ℃ in a vacuum atmosphere;
(d) placing the sample on a glass plate partially coated with silver paste;
(e) applying silver paste to both ends of the sample and compressing it with copper foil;
(f) heat-treating the sample within a temperature range of 100 to 140° C. in a vacuum atmosphere;
(g) applying a current corresponding to 0.5 to 4 A to the sample in a vacuum atmosphere for a time in the range of 1 to 4000 ms to apply a thermal shock to the sample; and
(h) growth of multi-component crystalline non-noble metal nanoparticles comprising the step of separating a sample from the glass plate, and a method for producing a carbon nanofiber membrane binding the same. 6. The method of claim 5,
In step (a), the solvent is formic acid, acetic acid, phosphoric acid, sulfuric acid, m-cresol, tifluoroacetanhydride/dichloromethane, water, N- Methylmorpholine N-oxide, chloroform, tetrahydrofuran and aliphatic ketone group methyl isobutyl ketone, methyl ethyl ketone, aliphatic hydroxyl group m-butyl alcohol, isobutyl alcohol, isopropyl alcohol, methyl alcohol, ethanol, aliphatic compounds Phosphorus hexane, tetrachloroethylene, acetone, propylene glycol, diethylene glycol, ethylene glycol as the glycol group, trichloroethylene, dichloromethane as the halogen compound group, toluene, xylene as the aromatic compound group, and cyclo as the alicyclic compound group Hexanone, cyclohexane and n-butyl acetate as an ester group, ethyl acetate, butyl cellosalb as an aliphatic ether group, 2-ethoxyethanol acetate, 2-ethoxyethanol, dimethylformamide as an amide, dimethylacetamide, and these containing one or more solvents selected from the group consisting of a mixture of
The source of the non-noble metal ion, characterized in that, is in the form of a metal salt including chloride (-Cl), iodide (-I), nitrate (-NO3) or a hydrate of the salts (·H ₂ O), in addition to the solvent Includes all types of substances, including target metal ions, that can be ionized by dissolving in them.
The total concentration of the precursor, characterized by having a range of about 0.005 - 0.1 M
Being able to control the composition of nanoparticles generated after the final process is carried out according to the type and composition of precursor ions characterized by
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that 6. The method of claim 5,
In step (b),
A carbon nanofiber membrane cut to an appropriate size is _{subjected to an O 2} plasma process with an intensity of 10 W to 200 W, and the defect elements on the surface are increased to strengthen the binding force with the solution precursors.
Put transferred to a Petri dish (Petri Dish) a precursor solution prepared in a proper width, characterized in O ₂ Plasma process and it is fully locked and an embodiment of a carbon nano-fiber membrane in a solution put in a Petri dish The precursor solution contained 1 Uniform dispersion coating of the precursor on the membrane surface by immersion for seconds to 24 hours
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that 6. The method of claim 5,
In step (c),
Evaporating the solvent of the precursor solution by heat-treating the carbon nanofiber membrane dispersedly coated with the precursor solution within a temperature range of 60 to 120° C. in a vacuum atmosphere.
Drying completely for 30 minutes to 24 hours or longer depending on the solvent depending on the solvent in the process characterized by
According to the solvent used, characterized in that the nanoparticle dispersion and the reduction ratio of metal ions after the final process can be controlled
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that 6. The method of claim 5,
In step (d),
The glass plate, which serves as the structure of the platform for large-area Joule heating, is not decomposed and damaged at 2000 °C or higher, unless a glass plate that is not modified at high temperature is used or the purpose is different, any support that does not affect the carbon nanofiber membrane to use
The size of the glass plate support, characterized by using a size larger than the size of the membrane to be used
The silver paste characterized by this is to serve as a current collector through which current flows during the Joule heating process, so apply it evenly to both ends of the glass plate to which the conductor will be connected.
The application range characterized in that it is limited to the outside of the area to be used as a sample in the membrane based on the center of the glass plate.
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that 6. The method of claim 5,
In step (e),
Applying silver paste uniformly so that it can be connected to the silver paste area applied to the glass plate on both ends
The copper foil is placed on both ends of the sample, characterized in that it is uniformly compressed with a flat plate so that the silver paste can be uniformly permeated into the pores of the carbon nanofiber membrane, thereby securing the path of current to evenly spread the current throughout the sample. to allow it to flow
At this time, characterized in that the copper foil is maintained or not maintained when passing current in the subsequent process, and includes using any type of foil and current collector metal that is conductive.
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that 6. The method of claim 5,
In step (f),
100 ~ 140 of the sample in a vacuum atmosphere Adjusting the temperature range of ℃ and within the time range of 1 to 24 hours to appropriately control the degree of removal of the solvent and polymer in the silver paste to increase the adhesion with the membrane and the stability of the sample during subsequent processes
Silver paste is characterized by dispersing silver particles with a diameter of several hundred nanometers to several micrometers in a polar solvent such as α-Terpineol, IPA, ethanol, and water. It is a formulation paste, which removes the polymer in the heat treatment process and dries the solvent to reduce the contact resistance between the current collector and the carbon nanofiber membrane.
Being able to produce a platform capable of large area juul heating characterized by
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that 6. The method of claim 5,
In steps (g) and (h),
Applying a thermal shock to the sample by applying a current corresponding to 0.5 to 4 A for a time in the range of 1 to 4000 ms to the platform obtained through step (f) in a vacuum atmosphere
Diffusion and reduction processes of metal ions existing in an ionic state in the carbon nanofiber membrane under a reducing atmosphere characterized in
When the heat generated by thermal shock is sufficiently generated, light is generated from the carbon nanofiber membrane, and the lower the temperature, the darker red, and the higher the temperature, the closer to white light.
The intensity of the thermal shock characterized by is proportional to the amount of power applied to the carbon nanofibers of the unit area.
Applying an appropriate voltage value and current value according to the resistance value of the carbon nanofiber membrane characterized in
It is possible to grow non-noble metal nanoparticles generated at low temperature, and nanoparticles generated at high temperature by controlling the amount of applied power, characterized in that
It is preferable to adjust the time to apply the power, characterized in that it is within the range of 1 to 4000 ms according to the target dispersion degree and the size of the particles, but including proceeding longer if necessary
It is possible to control the size of nanoparticles by repeating the thermal shock process at a specific time interval in the range of 10 ~ 4000 ms, characterized by
Separation by pressing both ends of the carbon nanofiber membrane area to which the Silper Paste is not applied, using a wide blade in the cross-sectional view, at once
A method for producing multi-component crystalline non-noble metal nanoparticles and binding carbon nanofiber membranes, characterized in that

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