KR102054559B1 - Pt-CoO NANO PARTICLE, MANUFACTURING METHOD OF THE SAME AND CATALYST COMPRISING THE SAME - Google Patents

Abstract

The present invention relates to a method for preparing hybrid platinum-cobalt oxide nanoparticles and nanoparticles prepared through the same, wherein the nanoparticles prepared through the present invention represent branched nanowires or core cube-shaped nanocubes. When graphene oxide is used as a support, it shows excellent efficiency, durability and stability as an oxygen reduction catalyst of a fuel cell.

Description

Pt-CoO nanoparticles, preparation method thereof and catalyst comprising the same {Pt-CoO NANO PARTICLE, MANUFACTURING METHOD OF THE SAME AND CATALYST COMPRISING THE SAME}

The present invention relates to metal nanoparticles, a method for preparing the same, and a catalyst comprising the same, and more particularly, to a hybrid Pt-CoO nanoparticle, a method for preparing the same, and a catalyst comprising the same.

Unlike the existing large metal materials, metal nanoparticles have been used in various fields because of their high surface area, high reactivity to various molecules, and new properties.

Meanwhile, in the case of hybrid nanoparticles, physical and chemical properties tend to be improved compared to nanoparticles formed of only a single metal, and thus, a possibility of being applied to various fields has been revealed. Among these hybrid metal nanoparticles, many techniques for manufacturing hybrid nanoparticles based on platinum (Pt) have also been developed. Among them, a method for producing nanoparticles using a solution growth method has been developed.

Among various hybrid nanocomposites, hybrid nanoparticles including platinum and cobalt oxide have also been developed, and have been mainly used as catalysts for redox reactions.

Recently, research on hybrid Pt-CoO nanoparticles has been progressed as the demand for a platinum-based catalyst having improved electrode catalyst activity and magnetic application increases. However, it is still difficult to control the shape of Pt-CoO nanoparticles, and it is necessary to study the method of preparing nanoparticles of various structures and the characteristics of various types of nanoparticles manufactured through the same.

One object of the present invention is to provide a Pt-CoO nanoparticles of a novel structure, a method for preparing the same, and a catalyst comprising the same.

Pt-CoO nanoparticle manufacturing method for one object of the present invention comprises a first step of heating a cobalt precursor solution containing a fatty amine, fatty acids and cobalt precursors; A second step of preparing a reaction mixture by mixing a platinum precursor solution including a platinum precursor with the heated cobalt precursor solution; A third step of heating the reaction mixture; A fourth step of cooling the heated reaction mixture; And a fifth step of centrifuging the cooled reaction mixture to form a branched nanowire.

Pt-CoO nanoparticle manufacturing method for another object of the present invention comprises a first step of heating a cobalt precursor solution containing a fatty amine, fatty acids and cobalt precursors; A second step of preparing a reaction mixture by mixing a platinum precursor solution including a platinum precursor with the heated cobalt precursor solution; A third step of heating the reaction mixture; A fourth step of cooling the heated reaction mixture; And a fifth step of centrifuging the cooled reaction mixture, and after the first step, adding a Fe (CO) ₅ solution. The Pt-CoO nanoparticles further include core @ shell nano. It is formed in the form of a cube (core @ shell nanocube).

In one embodiment, the cobalt precursor may be Co (acac) ₂ .

In one embodiment, the platinum precursor may be Pt (acac) ₂ .

In one embodiment, the solvent of the cobalt precursor solution and the platinum precursor solution may be 1-octadecene (ODE, 1-octadecene).

In one embodiment, the fatty amine may be oleylamine (OAm, Oleylamine).

In one embodiment, the fatty acid may be oleic acid (OA).

In one embodiment, the first step may be to heat the cobalt precursor solution first, and then to the second heating at a temperature higher than the first heating.

In one embodiment, the third step may be to heat the reaction mixture for 120 to 240 minutes.

In one embodiment, the third step may be to heat the reaction mixture to 170 ℃ to 230 ℃.

In one embodiment, the fourth step may be to cool the heated reaction mixture to room temperature.

In one embodiment, a cobalt precursor solution comprising 1-octadecene as solvent, oleyl amine as fatty amine, oleic acid as fatty acid, and Co (acac) ₂ as cobalt precursor is heated to 80 ° C. to 140 ° C. for 30 to 90 minutes. A first step of making; A second step of preparing a reaction mixture by mixing a platinum precursor solution including Pt (acac) ₂ with 1-octadecene, oleyl amine and platinum precursor to the heated cobalt precursor solution; A third step of heating the reaction mixture at 170 ° C. to 230 ° C. for 120 minutes to 240 minutes; A fourth step of cooling the heated reaction mixture to room temperature; And a fifth step of centrifuging the cooled reaction mixture using ethanol and hexane, thereby forming Pt-CoO nanoparticles in the form of branched nanowires.

In one embodiment, the Fe (CO) ₅ solution may be to add 6 μl to 24 μl.

In one embodiment, a cobalt precursor solution comprising 1-octadecene as solvent, oleyl amine as fatty amine, oleic acid as fatty acid, and Co (acac) ₂ as cobalt precursor is heated to 80 ° C. to 140 ° C. for 30 to 90 minutes. A first step of making; A second step of preparing a reaction mixture by mixing a platinum precursor solution including Pt (acac) ₂ with 1-octadecene, oleyl amine and platinum precursor to the heated cobalt precursor solution; A third step of heating the reaction mixture at 170 ° C. to 230 ° C. for 120 minutes to 240 minutes; A fourth step of cooling the heated reaction mixture to room temperature; And a fifth step of centrifuging the cooled reaction mixture using ethanol and hexane, and after the first step, adding 6 μl to 24 μl of Fe (CO) ₅ solution. , Pt-CoO nanoparticles in the form of a core @ shell nanocube may be formed.

Pt-CoO nanoparticles for another object of the present invention is prepared through the production method of the present invention, in the Pt-CoO nanoparticles Pt is crystalline, CoO may be amorphous.

Pt-CoO catalyst for another object of the present invention is prepared through the production method of the present invention, Pt-CoO nano formed in the form of branched nanowire (core @ shell nanocube) The particles are supported on graphene oxide.

In one embodiment, the Pt-CoO catalyst in which the branched nanowire-shaped Pt-CoO nanoparticles are supported on graphene oxide may exhibit a potential of 0.95 V or more in an oxygen reduction reaction.

In one embodiment, the Pt-CoO catalyst in which the Pt-CoO nanoparticles of the core @ shell nanocube form supported on graphene oxide may exhibit a potential of 0.90 V or more in an oxygen reduction reaction.

In one embodiment, the Pt-CoO catalyst may be used as an oxygen reduction catalyst of a fuel cell.

The present invention relates to Pt-CoO nanoparticles and a method of manufacturing the same, it is possible to produce Pt-CoO nanoparticles having a branched nanowire form and a concave core-shell structure nanocube form through the production method of the present invention. . In the case of the nanoparticles prepared through the present invention, since the oxygen reduction reaction is excellent, it can be used in the field of catalysts.

1 is a view showing an embodiment of the present invention.
2 and 4 are views showing the nanoparticles prepared according to one embodiment.
5 to 8 are diagrams showing the results of nanoparticle analysis.
9 shows a reaction intermediate.
10 to 12 are views showing a comparative example.
13 to 16 are diagrams showing the results of catalyst performance analysis.
17 and 18 are diagrams showing the results of stability evaluation.

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

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

Pt-CoO nanoparticle manufacturing method of the present invention comprises a first step of heating a cobalt precursor solution containing a fatty amine, fatty acids and cobalt precursors; A second step of preparing a reaction mixture by mixing a platinum precursor solution including a platinum precursor with the heated cobalt precursor solution; A third step of heating the reaction mixture; A fourth step of cooling the heated reaction mixture; And a fifth step of centrifuging the cooled reaction mixture to form a branched nanowire.

Another Pt-CoO nanoparticle manufacturing method of the present invention comprises a first step of heating a cobalt precursor solution containing a fatty amine (fatty amine), fatty acids (fatty acid) and cobalt (cobalt) precursor; A second step of preparing a reaction mixture by mixing a platinum precursor solution including a platinum precursor with the heated cobalt precursor solution; A third step of heating the reaction mixture; A fourth step of cooling the heated reaction mixture; And a fifth step of centrifuging the cooled reaction mixture, and after the first step, adding a Fe (CO) ₅ solution to the Pt-CoO nanoparticles by core @ shell nanos. It may be formed in the form of a cube.

In one embodiment, a cobalt compound may be used as the cobalt precursor. For example, cobalt (II) acetylacetonate (Co (acac) ₂ , Cobalt (II) acetylacetonate), dicobalt octacarbonyl, and Cobalt chloride (Cobaltous Chloride) may include at least one or more, for example, the cobalt precursor may be used using only Co (acac) ₂ .

In one embodiment, the platinum precursor may use a platinum compound, for example, platinum acetylacetonate (Pt (acac) ₂ , platinum acetylacetonate), platinum hexafluoroacetylacetonate and platinum hexaacetylacetonate It may include at least one or more, for example, the platinum precursor may be used using only Pt (acac) ₂ .

In one embodiment, the solvent of the cobalt precursor solution and the platinum precursor solution may be an organic solvent. For example, the solvent of the cobalt precursor solution and the platinum precursor solution may be 1-octadecene (ODE, 1-octadecene).

In one embodiment, the fatty amine may be an unsaturated fatty amine and a mixture comprising the same, for example the fatty amine may be oleylamine (OAm, Oleylamine). In the preparation method of the present invention, the fatty amine may be used as a reducing agent.

In one embodiment, the fatty acid may be a fatty acid compound, for example, oleic acid (OA). In the production method of the present invention, the fatty acid may be used as a surfactant or surface stabilizer.

For example, the cobalt precursor solution may be Co (acac) ₂ , 1-octadecene, oleic acid and oleylamine, and the platinum precursor solution is Pt (acac) ₂ , 1-octadecene and oleyl It may be one containing an amine.

In one embodiment, the first step may be to first heat the cobalt precursor solution and second heat. The primary heating may be performed to remove water in the cobalt precursor solution, and the secondary heating may pyrolyze Fe (CO) ₅ to form uniform nanoparticles when Fe (CO) ₅ is added. It may be to perform.

In one embodiment, the primary heating may be to heat to 80 ℃ or more, in order to dry the water that may be included in the cobalt precursor. For example, the cobalt precursor solution may be heated to 80 ° C. to 120 ° C. and left for 30 to 90 minutes. For example, when the cobalt precursor solution is first heated to a temperature lower than 80 ° C., water may be present in the cobalt precursor solution, and when the first heated cobalt precursor solution is left for less than 30 minutes, sufficient water There may be a problem that does not dry. For example, the cobalt precursor solution may be heated to 100 ° C. and then maintained for 60 minutes. In one embodiment, the heated cobalt precursor solution may be maintained in a vacuum state.

In one embodiment, the secondary heating may be to secondary heating the first heated cobalt precursor solution to 100 ℃ to 140 ℃. In one embodiment it may be to add Fe (CO) ₅ solution and then heated to 100 ℃ to 140 ℃. For example, the secondary heating may be to heat the primary heated cobalt precursor solution once more to 120 ° C. In one embodiment, the secondary heating may be performed for 15 minutes to 45 minutes. For example, the first heated cobalt precursor solution may be heated to 100 ° C. to 140 ° C. for 15 to 45 minutes. For example, when the secondary heating is performed at a temperature lower than 100 ° C., the thermal decomposition of Fe (CO) ₅ may not be sufficient, resulting in problems that uniform nanoparticles may not be formed, and the temperature may be higher than 140 ° C. In case of the second heating, pyrolysis of Fe (CO) ₅ occurs so rapidly that nanoparticle formation may be incomplete. In addition, if the heating time for less than 15 minutes, there may be a problem that the nanoparticles are not formed uniformly enough, if the heating is longer than 45 minutes may cause a problem that the aggregation of the nanoparticles occurs to form a non-uniform nanoparticles . For example, the secondary heating may be performed in the presence of argon gas. For example, the cobalt precursor solution may be heated to 120 ° C. and heated at 120 ° C. for 30 minutes in the presence of argon gas.

In one embodiment, the second step may be to prepare a reaction mixture (reaction mixture 1) by mixing the first heated cobalt precursor solution and the platinum precursor solution, the Fe in the first heated cobalt precursor solution (CO) A solution ₅ may be added, a mixed solution is prepared and heated secondly, followed by mixing the mixed solution and the platinum precursor solution to prepare a reaction mixture (reaction mixture 2).

The reaction mixture 2 was prepared by the addition of the Fe (CO) ₅ solution to the heated cobalt precursor solution to prepare a mixed solution, and then heated to 150 ℃ to 250 ℃, 10 minutes to 30 minutes After maintaining it may be to mix the platinum precursor solution. For example, in the reaction mixture 2, a mixed solution is prepared by adding the Fe (CO) ₅ solution to the heated cobalt precursor solution, and then heating the mixed solution to 200 ° C. and maintaining the temperature for 20 minutes. It may be to mix the platinum precursor solution.

In one embodiment, the third step may be to heat the reaction mixture for 120 to 240 minutes. In one embodiment, the third step may be to heat the reaction mixture to 170 ℃ to 230 ℃. For example, when the reaction mixture is heated for less than 120 minutes, cobalt oxide may not grow sufficiently, causing nanoparticles to be irregularly formed. If the reaction mixture is heated for more than 240 minutes, the deposition time of the cobalt oxide may be long and excessive. Growth and agglomeration between nanoparticles may occur, causing irregular nanoparticles to form. In addition, when the reaction mixture is heated to a temperature lower than 170 ° C. or higher than 230 ° C., irregular nanoparticles may be formed. For example, the third step may be heating the reaction mixture (reaction mixtures 1 and 2) to 200 ° C. for 180 minutes.

In one embodiment, the fourth step may be to cool the heated reaction mixture to room temperature.

In one embodiment, the fifth step of centrifugation may be performed by using an alcohol and a saturated hydrocarbon to dissolve the organic material well. For example, the fifth step of centrifugation may be performed using ethanol and hexane.

In one embodiment, a cobalt precursor solution comprising 1-octadecene as solvent, oleyl amine as fatty amine, oleic acid as fatty acid and Co (acac) ₂ as cobalt precursor is heated to 80 ° C. to 140 ° C. for 30 to 90 minutes. A first step of making; A second step of preparing a reaction mixture by mixing a platinum precursor solution including Pt (acac) ₂ with 1-octadecene, oleyl amine and platinum precursor to the heated cobalt precursor solution; A third step of heating the reaction mixture at 170 ° C. to 230 ° C. for 120 minutes to 240 minutes; A fourth step of cooling the heated reaction mixture to room temperature; And a fifth step of centrifuging the cooled reaction mixture using ethanol and hexane, thereby forming Pt-CoO nanoparticles in the form of branched nanowires.

For example, a cobalt precursor solution comprising 1-octadecene, oleyl amine, oleic acid, and Co (acac) ₂ is heated to 100 ° C., maintained under vacuum for 1 hour, and then slowly to 120 ° C. Heating the platinum precursor solution comprising Pt (acac) ₂ with 1-octadecene, oleyl amine and platinum precursor, the first step of heating first and secondly heating to 120 ° C. for 30 minutes in the presence of argon gas. A second step of preparing a reaction mixture by mixing in a cobalt precursor solution, a third step of heating the reaction mixture at 200 ° C. for 180 minutes, a fourth step of cooling the heated reaction mixture to room temperature, and ethanol and hexane By using a fifth step of centrifuging the cooled reaction mixture by using, it is possible to form Pt-CoO nanoparticles in the form of branched nanowires.

In one embodiment, the Fe (CO) ₅ solution may be to add 6 μl to 24 μl. When the Fe (CO) ₅ solution is added to 5 μl or less, nanocube forms are not formed and round nanoparticles are formed, and when 25 μl is added, non-uniform nanoparticles are formed. This can happen.

The Fe (CO) ₅ solution may include at least one of 1-octadecene, oleic acid, and oleylamine. For example, the additive solution may be one containing Fe (CO) ₅ and 1-octadecene.

In one embodiment, a cobalt precursor solution comprising 1-octadecene as solvent, oleyl amine as fatty amine, oleic acid as fatty acid, and Co (acac) ₂ as cobalt precursor is heated to 80 ° C. to 140 ° C. for 30 to 90 minutes. A first step of making; A second step of preparing a reaction mixture by mixing a platinum precursor solution including Pt (acac) ₂ with 1-octadecene, oleyl amine and platinum precursor to the heated cobalt precursor solution; A third step of heating the reaction mixture at 170 ° C. to 230 ° C. for 120 to 240 minutes; A fourth step of cooling the heated reaction mixture to room temperature; And a fifth step of centrifuging the cooled reaction mixture using ethanol and hexane, and further comprising adding a Fe (CO) ₅ solution after the first step, thereby further comprising: core @ shell nano Pt-CoO nanoparticles in the form of a cube (core @ shell nanocube) may be formed.

For example, a cobalt precursor solution comprising 1-octadecene, oleyl amine, oleic acid, and Co (acac) ₂ is heated to 100 ° C., maintained under vacuum for 1 hour, and then slowly to 120 ° C. The first step of heating, the second step of heating to 120 ℃ for 30 minutes in the presence of argon gas, after the first step to add a Fe (CO) ₅ solution to prepare a mixed solution, 1-octadecene, ole A second step of preparing a reaction mixture by mixing a platinum precursor solution containing Pt (acac) ₂ with one amine and a platinum precursor to the mixed solution, a third step of heating the reaction mixture at 200 ° C. for 180 minutes, A fourth step of cooling the heated reaction mixture to room temperature and a fifth step of centrifuging the cooled reaction mixture using ethanol and hexane, thereby forming Pt in the form of a core @ shell nanocube. -CoO nanoparticles formed Can.

Pt-CoO nanoparticles for another object of the present invention is prepared through the production method of the present invention, is formed in the form of branched nanowire (branched nanowire) or core @ shell nanocube (core @ shell nanocube) and the Pt- In CoO nanoparticles Pt may be crystalline and CoO may be amorphous.

In one embodiment, the Pt-CoO nanoparticles can be used as a catalyst, for example as an electrochemical catalyst. For example, the Pt-CoO nanoparticles may be supported on a support to improve stability or durability, and may be used as a catalyst having improved properties. The support may be graphene oxide, for example, the nanoparticles may be supported on graphene oxide and used as a catalyst.

Pt-CoO catalyst for another object of the present invention is Pt-CoO nanoparticles formed in the form of branched nanowire (core @ shell nanocube) branched through the production method of the present invention. It is supported on pin oxide.

In one embodiment, the Pt-CoO catalyst having the branched nanowire-shaped Pt-CoO nanoparticles supported on graphene oxide may exhibit a potential of 0.95 V or more in an oxygen reduction reaction. For example, the Pt-CoO catalyst in which the branched nanowire-shaped Pt-CoO nanoparticles are supported on graphene oxide may exhibit a potential of 0.98 V in an oxygen reduction reaction.

In one embodiment, the Pt-CoO catalyst having Pt-CoO nanoparticles in the form of the core @ shell nanocube supported on graphene oxide may exhibit a potential of 0.90 V or more in an oxygen reduction reaction. For example, the Pt-CoO catalyst having Pt-CoO nanoparticles in the form of the core @ shell nanocube supported on graphene oxide may exhibit a potential of 0.93 V in an oxygen reduction reaction.

In one embodiment, the Pt-CoO catalyst may be used as an oxygen reduction catalyst of a fuel cell.

Branched Pt-CoO nanoparticles (NWs) in the form of nanowires branched in a one-pot system (NWs), Pt-CoO nanoparticles in the form of concave core @ shell nanocube ( core @ shell concave nanocubes) (NCs) and methods for their preparation can be provided. In addition, the production method of the present invention can control the form of the platinum seed (seed) by adjusting the amount of Fe (CO) ₅ during the production of Pt-CoO nanoparticles. Therefore, it is possible to control the shape of the hybrid Pt-CoO nanoparticles through the present invention.

In addition, Aliviasatos et al. The Kirkendall effect caused the decomposition and reduction of metal precursors to develop Pt @ CoO core @ shell nanoparticles, and Pt _m Co _m / CoO _1-x nanorods were used for the water-gas shift. It can be used as an effective catalyst for the reaction.

In the case of producing Pt-CoO nanoparticles, in the absence of Fe (CO) ₅ , branched Pt-CoO nanowire-type nanoparticles were synthesized by attaching small platinum seed particles and growing cobalt oxide by deposition. Can be. On the other hand, when Pt-CoO nanoparticles are prepared, when Fe (CO) ₅ is added, cobalt is more strongly adsorbed on the platinum surface than the dense surface, and thus a concave nanocube of Pt @ CoO core @ shell structure can be synthesized. It also assesses the effects of reaction kinetics on the synthesis by adjusting other conditions such as reducing agents, precursor concentrations and stabilizing agents. It was. Compared to Pt / graphene oxide (GO) catalysts, the nanoparticles in the form of branched Pt-CoO nanowires of the present invention supported on graphene oxide are characterized by the oxygen reduction reaction. Enhanced activity against (ORR).

The shape of the noble metal nanoparticles can be controlled by either thermodynamic or kinetic control in solution. Dual thermodynamic control may be influenced by the chemical potential which depends on the temperature of the solution and the supersaturation of the solution. On the other hand, in the motion control, the shape of the noble metal nanoparticles can be controlled by changing the reaction conditions of various shapes having different sizes. Among others, additives such as halides, metal ions and metal salts may be efficient directors in the form of metal nanoparticles. Thus, it can be seen that such additives can control the growth rate of specific facets leading to the desired morphology of the metal nanoparticles. However, it was still difficult to control the morphology of hybrid platinum-cobalt oxide nanoparticles using trace additives.

Therefore, by controlling the amount of the metal-metal oxide nanoparticles and the additive Fe (CO) ₅ can provide a method for controlling the form of the metal-metal oxide nanoparticles through the present invention, Pt-CoO nano of the present invention Through the particle preparation method, it is possible to produce Pt-CoO nanoparticles whose morphology is controlled and which exhibits superior durability, stability and catalytic efficiency.

Hybrid platinum-cobalt oxide nanostructures as electrochemical catalysts in the field of catalysts are attracting attention as the interface region between platinum and cobalt oxide is formed, and in addition to forming such hybrid nanostructures, it also crosses the metal / graphene oxide interface. Since there is a transfer of charge, a unique support such as graphene oxide can be used to improve the activity and stability of the catalyst. Pt-CoO nanoparticles supported on graphene oxide can be used as a catalyst for the oxygen reduction reaction.

The present invention relates to a monodisperse hybrid (Hybrid) Pt-CoO nanoparticles and a method for manufacturing the same, the Pt-CoO nanoparticles may be in the form of branched nanowires and core @ shell nanocube. The nanoparticles can be used as a catalyst for the oxygen reduction reaction of the fuel cell, it can be seen through the present invention that the nanostructure of the Pt-CoO nanoparticles are selectively formed according to the addition amount of Fe (CO) ₅ . Therefore, it can provide a specific synthetic route of the concave Pt @ CoO nanocube-shaped nanoparticles, it is possible to control the shape of the Pt-CoO nanoparticles. In the electrochemical aspect, the catalyst prepared by loading Pt-CoO nanoparticles in the form of branched nanowires on graphene oxide (GO) promotes an oxygen reduction reaction in 0.1 M HClO ₄ aqueous solution, Higher activity than Pt / GO catalyst. Therefore, Pt-CoO nanoparticles exhibiting excellent durability, stability and catalytic efficiency can be prepared through the present invention.

1 is a view showing an embodiment of the present invention. Specifically, FIG. 1 is a view schematically showing a method for preparing Pt-CoO nanoparticles and a form of Pt-CoO nanoparticles prepared through the same according to an embodiment of the present invention. Referring to FIG. 1, the Pt-CoO nanoparticles of the present invention may be prepared through the preparation method of the present invention comprising mixing the cobalt precursor and the platinum precursor and heating the temperature to 200 ° C. FIG. In this case, the cobalt precursor may include Co (acac) ₂ . The platinum precursor may also include Pt (acac) ₂ .

Hereinafter, embodiments of the present invention will be described in detail. However, the following examples are only some embodiments of the present invention, and the present invention should not be construed as being limited to the following examples.

Example 1 Preparation of Branched Nanowire Particles

0.129 g of Co (acac) ₂ , 10 mL of 1-octadecene, 1 mL of oleic acid, and 1 mL of oleylamine were mixed to obtain a cobalt precursor solution. The cobalt precursor solution was then under vacuum at 100 ° C. for 1 hour and then slowly heated from 60 ° C. to 120 ° C. for 10 minutes. Under an blanket of argon, heated at 120 ° C. for 30 minutes. Then, a platinum precursor solution prepared by mixing platinum (II) acetylacetonate (Pt (acac) ₂ , Platinum (II) acetylacetonate), 4 ml of 1-octadecene and 1 ml of oleylamine was added to the heated cobalt precursor solution. To give a reaction mixture, which was maintained at 200 ° C. for 3 hours. The reaction mixture was then cooled to room temperature. The reaction mixture was centrifuged with ethanol and hexane, and the product was dispersed in hexane to obtain a Pt-CoO solution. Hybrid platinum-cobalt oxide nanoparticles may form an interface between platinum and cobalt oxide.

Example 2 Preparation of @ Core @ Shell Nanocube Particles

0.129 g of Co (acac) ₂ , 10 mL of 1-octadecene, 1 mL of oleic acid, and 1 mL of oleylamine were mixed to obtain a cobalt precursor solution. The cobalt precursor solution was then vacuumed at 100 ° C. for 1 hour and then slowly heated from 60 ° C. to 120 ° C. for 10 minutes. Under an argon blanket, it was heated at 120 ° C. for 30 minutes. Then, a small amount of an additive solution (0.1 ml) prepared by mixing 0.05 ml to 0.25 ml of Fe (CO) ₅ and 1 ml of 1-octadecene (0.1 ml) was added to the cobalt precursor solution to obtain a mixed solution. The temperature of the mixed solution was increased by 4 ° C./min, heated to 200 ° C., and maintained at 200 ° C. for 30 minutes. Thereafter, a platinum precursor solution prepared by mixing Pt (acac) ₂ , 4 ml of 1-octadecene and 1 ml of oleylamine was added to the mixed solution to obtain a reaction mixture, and the reaction mixture was stirred at 200 ° C. for 3 hours. Kept for a while. The reaction mixture was then cooled to room temperature. The reaction mixture was centrifuged with ethanol and hexane, and the product was dispersed in hexane to obtain a Pt-CoO solution. Hybrid platinum-cobalt oxide nanoparticles may form an interface between platinum and cobalt oxide.

Catalyst manufacturing

Since the charge can be moved across the metal / graphene oxide interface, graphene oxide (GO) or the like can be used as a support to improve the activity and stability of the catalyst.

The activity of the oxygen reduction reaction (ORR) of the nanoparticles of the present invention (particularly, Pt-CoO nanoparticles of branched nanowire structure) supported on graphene oxide is platinum / graphene oxide ( Pt / GO) catalysts.

Pt-CoO solution dispersed in 20 ml of hexane was mixed with 20 mL of dimethylformamide (DMF, dimethylformamide) containing graphene (2.5 mg / mL) and sonicated for 1 hour. After sonication, the powder was suspended in 40 mL of acetic acid. The suspension was heated at 70 ° C. overnight to remove the surfactant around the nanoparticles. The product was then centrifuged (8000 rpm, 10 minutes), washed twice with ethanol and dried.

Property evaluation

Each sample was formed by adding a few drops of the corresponding colloidal solution onto a carbon coated copper grating (200 mesh, F / C coated, Ted Pella Inc., Redding, Calif., USA), TEM (FEI TALOS F200X operated at 200). kV, Pusan National University).

XRD patterns were recorded on a Rigaku D / MAX-RB (12 kW) diffractometer and XPS (Theta Probe, Thermo) was used to measure the structural and chemical properties of nanocomposites.

Evaluation was made using a three electrode electrochemical cell with a potentiostat (Biologic VSP).

Durability tests were performed with 0.1 M HClO ₄ solution oxygen saturated at room temperature, with periodic potential sweeps of 0.6 V to 1.1 V (relative to RHE) and a sweep rate of 50 mV / s for 4000 cycles.

The effects of reaction kinetics on the synthesis of Pt-CoO nanoparticles can also be controlled by controlling other conditions such as reducing agents, precursor concentrations and stabilizing agents as precursors. synthesis).

Electrochemical measurement

All electrochemical evaluations of the nanoparticles and nanoparticle catalyst samples prepared through the examples were performed at room temperature and atmospheric pressure.

A well dispersed nanoparticle catalyst sample prepared through one embodiment of the present invention was deposited to about 5 mm in diameter of the glassy carbon (GC) electrode used as the working electrode. Platinum wire and Ag / AgCl electrodes were used as the counter and reference electrodes, respectively, and 0.1 M HClO ₄ (pH 1.0) was used as the electrolyte. All catalysts removed oleylamine adsorbed on platinum under heat treatment (3% H ₂ / Ar) at 300 ° C. for 3 hours. Samples were mixed with 89.6 ml of distilled water, 10 ml of isopropanol and 0.4 ml of Nafion solution. 30 μl of ink was dropped on the working electrode (40 μg metal / cm ² ) surface in order to increase the binding force of the electrode surface.

2 and 4 are views showing the nanoparticles prepared according to one embodiment. Specifically, FIG. 2 is a transmission electron microscope (TEM) of Pt-CoO-n nanoparticles prepared by changing the amount of additive Fe (CO) ₅ when preparing hybrid Pt-CoO-n nanoparticles according to an embodiment of the present invention. , transmission electron microscopy). In this case, n represents the addition amount of the additive Fe (CO) ₅ 0 μl to 25 μl in the reaction mixture. Referring to (a) of FIG. 2, in which Fe (CO) ₅ is not added, a branched nanowire form through the oriented attachment of small platinum nanoparticles followed by the deposition of cobalt oxide on platinum. It can be seen that the Pt-CoO-0 nanoparticles were prepared.

It was confirmed that the morphology of the Pt-CoO nanoparticles was changed from the introduction of a certain amount of the additive Fe (CO) ₅ (about 5 μl or more), and the form was determined according to the amount of the additive Fe (CO) ₅ added. And (b), (c) and (d) of FIG. 2, in which the amount of the additive Fe (CO) ₅ was increased to 5 μl, 10 μl and 15 μl while keeping the other conditions the same, Pt-CoO nano It can be seen that the shape changes from the irregular shape to the core-shell concave cube structure. And (e) of Figure 2 showing the form of the Pt-CoO nanoparticles when the amount of the additive Fe (CO) ₅ to 20 μl, Pt-CoO nanoparticles prepared by adding 15 μl of the additive ( As shown in d), the concave nanocube form is shown, and the structure shown in (d) of FIG. 2 and the structure shown in (e) are not significantly different. However, when the additive Fe (CO) ₅ is prepared by adding about 25 μl, FIG. 2 (f) shows that the shape uniformity of the nanoparticles is significantly reduced. By controlling the amount of the additive Fe (CO) ₅ through Figure 2, it can be seen that the composition of the final product, the nanostructure can be easily manipulated, and the shape control from the branched nanowire to the core @ shell structure.

Specifically, FIG. 3 shows low resolution TEM images of Pt-CoO-0 and Pt-CoO-15 and Pt-CoO-20 particles having a branched structure, and FIG. The average diameter of Pt-CoO-15 shown in Fig. 3 is about 12 nm, and the average diameter of Pt-CoO-20 shown in Fig. 3 (c) is about 13 nm, and the purity of almost 100% is obtained. It is shown.

Specifically, Figure 4 is a view showing a comparative example of the nanoparticles prepared according to one embodiment, showing a TEM image of the platinum nanoparticles of the nanocube form synthesized without adding Co (acac) ₂ as a precursor.

5 to 8 are diagrams showing the results of nanoparticle analysis.

Specifically (a) of Figure 5 shows the X-ray powder diffraction (XRD) pattern of the Pt-CoO nanoparticles prepared in accordance with an embodiment of the present invention, Figure 5 (b) and (c) are respectively Pt The high-resolution TEM (HR-TEM) images of CoO-0 / GO and Pt-CoO-15 / GO are shown. The crystal structure of each sample was specified by XRD as shown in FIG. All diffraction peaks of the XRD pattern exhibited the face-centered cubic (fcc) structural features of platinum (ICSD # 64917). Through the high-resolution TEM image of the nanoparticles in the form of Pt-CoO-15 nanocube and the nanoparticles in the form of Pt-CoO-0 nanowire shown in FIGS. 5B and 5C, respectively, highly crystalline with lattice stripes The formation of platinum particles can be confirmed. The line spacing of 0.225 nm, shown in FIG. 5 (b), can be indexed for the platinum 111 reflections of the face-centered cubic structure. Since the presence of crystalline cobalt oxide was not confirmed in FIG. 5, it can be seen that the cobalt oxide is in an amorphous phase. In general, cobalt oxide may be formed in an amorphous phase because high solution temperature conditions and hot water above 200 ° C. are required for crystalline cobalt oxide synthesis. As a result, the Pt-CoO nanoparticles of the present invention may be one in which Pt is crystalline and CoO is amorphous.

6 illustrates the high-angle annular dark-field scanning TEM (HAADF-STEM) image of platinum and cobalt. (A) of FIG. 6 shows nanoparticles in the form of Pt-CoO-15 / GO core @ shell nanocubes, and FIG. 6 (b) shows the nanoparticles of branched Pt-CoO-0 / GO nanowires. As shown, each nanoparticle was analyzed. FIG. 6 (a) showing an image of nanoparticles in the form of Pt-CoO-15 / GO core @ shell nanocube shows that the shell contains cobalt oxide (green) and the core contains platinum (red). Able to know. On the other hand, in Figure 6 (b) showing the branched Pt-CoO-0 / GO nanowire-shaped nanoparticles, it can be seen that the platinum and cobalt oxide dispersed in all areas.

Specifically, FIG. 7 shows the results of elemental analysis of Pt, Co and C of Pt-CoO-15 / GO and Pt-CoO-0 / GO using X-ray photoelectron spectroscopy (XPS). It is shown. The XPS spectrum of Pt-CoO-15 / GO is shown in (a), (b) and (c) of FIG. 7, and Pt-CoO-0 / is shown in (d), (e) and (f) of FIG. The XPS spectrum of GO is shown. Referring to FIGS. 7A and 7B, in both embodiments, the binding energies of platinum 4f _7/2 and platinum 4f _5/2 doublet, which are characteristic of metallic Pt, are represented. ). 7 (b) and (e), it can be seen that the Co 2p _3/2 peak can be deconvoluted into two components. In the case of Pt-CoO-15 / GO, the strongest peak appeared at 780.6 eV representing Co 2p _3/2 and the peak at 784.8 eV representing Co ²⁺ satellite. Both peaks indicate the presence of cobalt oxide on the surface of the platinum nanostructures. Referring to (C) and (f) of FIG. 7, the binding energy of CC showed a peak at 284.5 eV, and shifts of + 1.6 eV and +3.5 eV generally indicate CO and C═O functional groups, respectively. will be.

Specifically, FIG. 8 shows TEM images of Pt-CoO nanoparticles obtained using Cr (CO) ₆ , W (CO) ₆ and excess carbon monoxide (CO) instead of Fe (CO) ₅ as additives (a), ( b) and (C) are shown. In order to confirm the influence of the external metal in the synthetic process, the comparison result by adding another material instead of the same molar ratio of Fe (CO) ₅ as a result of the nano-cube particles without shell structure It could be confirmed that was prepared. Referring to (a) and (b) of FIG. 8, Cr (CO) ₆ and W (CO) ₆ were added as additives, respectively, and the core @ shell Pt-CoO structure was not formed. It can be seen that the core @ shell Pt-CoO structure is formed only when (CO) ₅ is used. On the other hand, since the nanocube-type platinum nanoparticles can be promoted by the presence of carbon monoxide, the result of using an excess of carbon monoxide gas in place of the additive is shown in (c) and (d) of FIG. When excess carbon monoxide gas was injected into the reaction mixture instead of the additive, small particles were synthesized, and it was confirmed that the carbon monoxide molecules could be used as a reducing agent and a capping ligand. It can be seen that carbon monoxide reduction / binding effects are associated with the formation of nanoparticles. At a fixed ratio of oleic amine (OAm) / oleic acid (OA), the adsorption of carbon monoxide on platinum atoms is stronger at the (100) surface than at the dense (111) surface. Thus, the presence of carbon monoxide molecules from Fe (CO) ₅ may be an important factor for forming the cube structure. As a result, since an appropriate amount of iron ions and carbon monoxide molecules are provided from Fe (CO) ₅ injected into the reaction mixture, it can be seen that a core @ shell Pt @ CoO nanostructure is produced.

9 shows a reaction intermediate. Specifically, FIG. 9 illustrates Pt-CoO-20 nanoparticles to confirm a detailed mechanistic understanding of the structural evolution of Pt @ CoO nanocube structure into nanoparticles through time-dependent images of reaction intermediates. A transient TEM image of the reaction intermediate of the particles is shown. Referring to Figure 9 (a) it can be seen that the initial spherical (spherical) cobalt oxide seed nanoparticles were formed at 200 ℃ before the Pt (acac) ₂ injection. 9 (b), the platinum nanocube was formed after the Pt (acac) ₂ injection and before the cobalt oxide particles were deposited. As a result, it can be seen that the Pt @ CoO core @ shell nanocube structure is formed through the formation of the nanocube-type platinum nanoparticles and subsequent deposition of cobalt oxide on the nanocube-type platinum nanoparticles.

10 to 12 are views showing a comparative example.

Specifically, Figure 10 shows the evaluation results for confirming the effect of the reaction kinetic (reaction kinetic) on the synthesis of Pt-CoO nanoparticles. At this time, the reducing power can be controlled through the reducing agent oleyl amine, to prepare Pt-CoO nanoparticles by adding 2 ml of oleyl amine and 0.5 ml of oleyl amine, respectively, to compare the reduction kinetics. As a result of the analysis, each is shown in FIGS. 10A and 10B. And shown to Co (acac) ₂ and 1 mmol Co (acac) ₂ in the Pt-CoO 10 nanoparticles prepared by respectively the addition of 0.25 mmol (c) and (d). As a result of FIG. 10 (a), when the initial amount of oleyl amine was increased to 2 ml, different irregular nanostructures were formed on the small particles, thereby self-assembly of the small particles. assembly) was confirmed to occur. If the reduction rate is extremely high, a huge number of nuclei are formed, which may affect the self-assembly process. On the other hand, it can be seen from (b) of Figure 10 that the smaller nanocube-type platinum nanoparticles are formed by slower kinetics (slower reduction kinetics) only when the initial amount of the oleyl amine is 0.5 ml. Controlling the concentration of precursors due to monomer concentration and chemical potential can be a decisive factor in directional growth under kinetic controlled conditions. For example, using a high concentration of a metal compound as a precursor can form platinum nanoparticles of a branched structure. The shape of the synthesized nanoparticles can be changed by varying the amount of Co (acac) ₂ used to synthesize the nanoparticles. For example, when nanoparticles are prepared by increasing the amount of Co (acac) ₂ to 1 mmol, small nanoparticles may be attached by the high chemical potential of the cobalt oxide particles. Therefore, nanoparticles in the form of concave Pt @ CoO nanocubes may be formed. In addition, the shape of the nanoparticles may be controlled by a combination of stabilizers having different functional groups such as acids or amines having different binding strengths. Since oleic acid is a weaker surfactant for platinum than oleyl amine, it can promote nanoparticle growth into the nanocube structure.

Specifically, FIG. 11 compares the steric hindrance effect by replacing oleic acid with the same molar amount of adamantaneacetic acid while keeping all other reaction conditions the same, (a) and (b) It is shown in. 11 (a), it can be seen that due to the steric hindrance effect, bonding becomes difficult on the atomic surface, and thus irregular Pt-CoO nanocrystals can be formed. Referring to Figure 11 (b), it can be seen that in the absence of oleic acid, Pt @ CoO nanoparticles are formed in a much more rounded shape. Thus, it can be seen that oleic acid is an important factor in sharpening the edge of the polyhedron during nanoparticle synthesis.

Specifically, Figure 12 shows a TEM image of Pt-CoO-20 nanoparticles synthesized at 160 ℃ to compare the shape of the nanoparticles with temperature. When Pt (acac) ₂ is reduced at a low temperature (160 ° C.) lower than 200 ° C., Pt-CoO nanocrystals having irregular nanocube forms may be formed. Therefore, it can be seen that the temperature condition is also an important factor in the nanoparticle formation.

13 to 16 are diagrams showing the results of catalyst performance analysis.

Oxygen reduction reaction activity was evaluated by thin-film rotating disk electrode (TF-RDE).

Specifically, (a), (b), (c) and (d) of FIG. 13 correspond to Pt / GO, Pt-CoO-0 / GO, Pt-CoO-15 / GO, and Pt-CoO-20 / GO, respectively. Cyclic voltammograms are shown, and FIGS. 14A, 14B, and 14C show Pt / GO, Pt-CoO-0 / GO, Pt-CoO-15 / GO, and Pt-. Oxygen reduction reaction polarization curves are shown for comparison of the electrochemical activity of CoO-20 / GO. Figure 14 (a) is the oxygen reduction reaction polarization curve at 1600 rpm, Figure 14 (b) Tafel plot for the oxygen reduction reaction measured at 1600 rpm Figure 14 (c) is Koutecky-Levich 400 rpm, 0.3 V vs. measured at 900 rpm, 1600 rpm, 2500 rpm. Oxygen reduction reaction in RHE is shown. Prior to performing the electrode catalyst performance, all catalysts were subjected to heat treatment (3% H ₂ / Ar) at 300 ° C. for 3 hours to remove oleylamine adsorbed to platinum. Oxygen reduction reaction curve was measured at a scan rate of 10 mV s ^-1 at 1600 rpm. 14 (a), the sample showing the highest onset potential of 0.98 V is Pt-CoO-0 / GO, and Pt-CoO-20 / GO is 0.93 V, Pt / GO and Pt-CoO-15 / It was confirmed that the activity of GO is expressed as 0.90 V. In kinetics and diffusion control, it can be seen that the significant ohmic loss is found in all Pt-CoO / GO samples by the core @ shell structure. As a result of TEM, Pt-CoO-15 / GO exposed to the surface of cobalt oxide blocked the active surface of platinum, and as a result, Pt-CoO-15 / GO showed very low oxygen reduction activity. It was confirmed that Pt-CoO-0 / GO, which had high surface exposure of platinum atoms, exhibited excellent oxygen reduction reaction activity.

Referring to (b) of Figure 14, it shows the slope of the oxygen reduction reaction kinetic current of Pt / GO and Pt-CoO-0 / GO and divided the platinum metal into two for comparison. Two polarization curves were obtained, respectively, of pure platinum at low potential and Pt-CoO mixture at high potential (low Tafel slope: 60 mV dec ^-1 and 120 mV dec ^-1 ). The measured Tafel slope showed lower Pt-CoO-0 / GO due to surface blockage by cobalt oxide.

14 (c) shows the Koutecky-Levich slope for the oxygen reduction reaction in Pt / GO and Pt-CoO-0 / GO. The slope shown in this figure represents the reverse current density (J ^-1 ) as a function of the inverse square root of the rotational speed (ω ^-1/2 ) and can show first-order kinetics for molecular oxygen. . The slope was calculated by linear fitting, and the 4-electron transfer reaction was confirmed with an n value of about 4. The value of n was then calculated to be 3.78 for Pt-CoO-0 / GO and 3.68 for Pt / GO, indicating a nearly 4-electron transfer process for the oxygen reduction reaction.

Specifically, Figure 15 shows the presence or absence of oleyl amine from the nanoparticles, the bottom red line shows the FT-IR spectrum of Pt-CoO-0 / GO after heat treatment, the blue line above the The FT-IR spectrum of Pt-CoO-0 / GO is shown. 15, it can be seen that the intensity of methyl stretching of the oleylamine shown in 2920 cm ^-1 to 2850 cm ^-1 is reduced. Through the heat treatment it can be seen that the oleylamine was removed from the surface of the platinum.

Specifically, FIG. 16 shows the polarization curves of oxygen reduction reactions of Pt-CoO / GO (red line) and Pt / GO (black line) prepared by adding carbon monoxide gas, and the addition of additional carbon monoxide gas at 1600 rpm. The starting potential of Pt-CoO / GO in which nanocube-shaped Pt-CoO nanoparticles were synthesized on graphene oxide was about 0.97 V higher than that of Pt / GO under the influence of small monodisperse platinum nanoparticles. .

17 and 18 are diagrams showing the results of stability evaluation.

Specifically, Figure 17 shows the methanol poisoning effect in the oxygen reduction activity, Pt-CoO- at a fixed potential (1600 rpm) (vs. RHE with 1600 rpm rotation rate) of 0.05 V in 0.1 M HClO ₄ of 2000 μM Investigation was made by measuring the current of the 0 / GO electrode. The initial 1000 seconds of amperometry was performed under oxygen saturation conditions, followed by addition of 3 M methanol under oxygen saturation conditions for 1000 seconds to 2000 seconds. It can be seen that the Pt-CoO-0 / GO electrode has excellent methanol tolerance because of a slight decrease in current density even after adding 3 M methanol.

Specifically, FIG. 18 shows TEM images before (a) and after (b) long-term stability test of nanoparticles, and potential cycling between 0.6 V and 1.1 V for long-term stability evaluation. After the cycling, the type of Pt-CoO-0 / GO was examined. The evaluation result shows that the Pt-CoO-0 / GO catalyst maintains well-defined branched nanowire structure even after long-term stability test. Through this, it can be seen that the nanoparticles of the present invention have excellent stability and recyclability with respect to acidic reaction conditions.

As a result, the present invention can provide a method for single-port synthesis of hybrid Pt-CoO nanostructures through controlled reduction of metal precursor compounds, wherein the Fe (CO) ₅ additive is a decisive factor controlling the morphology of nanoparticles This can be It can be seen that the morphological evolution associated with nanoparticles is the formation of structures through the initial growth of the initial platinum seed followed by subsequent growth of cobalt oxide.

The effect of the reaction kinetics on the synthesis of Pt-CoO nanoparticles of the present invention was confirmed by changing the synthetic conditions such as the control of the reducing agent, the concentration of the metal compound used as the precursor and the stabilizer. Among the synthesized nanoparticles, Pt-CoO-0 / GO catalysts having Pt-CoO-0 supported on graphene oxide showed the highest activity for oxygen reduction reactions, and other multi-metal nanoparticles for electrocatalysis. It can also be applied to particle systems.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (19)

A first step of heating a cobalt precursor solution comprising a fatty amine, a fatty acid and a cobalt precursor;
A second step of preparing a reaction mixture by mixing a platinum precursor solution including a platinum precursor with the heated cobalt precursor solution;
A third step of heating the reaction mixture;
A fourth step of cooling the heated reaction mixture; And
A fifth step of centrifuging the cooled reaction mixture,
In the first step, a cobalt precursor solution including 1-octadecene as a solvent, oleyl amine as a fatty amine, oleic acid as a fatty acid, and Co (acac) ₂ as a cobalt precursor is 30 to 90 minutes at 80 ° C to 140 ° C. Heating during,
The second step includes mixing a platinum precursor solution including Pt (acac) ₂ as 1-octadecene, oleyl amine and platinum precursor to the heated cobalt precursor solution to prepare a reaction mixture,
The third step includes heating the reaction mixture to 170 to 230 ℃ for 120 minutes to 240 minutes,
The fourth step includes cooling the heated reaction mixture to room temperature,
The fifth step includes centrifuging the cooled reaction mixture with alcohol and hexane, thereby forming Pt-CoO nanoparticles in the form of branched nanowires.
Method for producing Pt-CoO nanoparticles.
A first step of heating a cobalt precursor solution comprising a fatty amine, a fatty acid and a cobalt precursor;
A second step of preparing a reaction mixture by mixing a platinum precursor solution including a platinum precursor with the heated cobalt precursor solution;
A third step of heating the reaction mixture;
A fourth step of cooling the heated reaction mixture; And
A fifth step of centrifuging the cooled reaction mixture,
After the first step, further comprising the step of adding a Fe (CO) ₅ solution;
In the first step, a cobalt precursor solution including 1-octadecene as a solvent, oleyl amine as a fatty amine, oleic acid as a fatty acid, and Co (acac) ₂ as a cobalt precursor is 30 to 90 minutes at 80 ° C to 140 ° C. Heating during,
The second step includes mixing a platinum precursor solution including Pt (acac) ₂ as 1-octadecene, oleyl amine and platinum precursor to the heated cobalt precursor solution to prepare a reaction mixture,
The third step includes heating the reaction mixture to 170 to 230 ℃ for 120 minutes to 240 minutes,
The fourth step includes cooling the heated reaction mixture to room temperature,
The fifth step includes centrifuging the cooled reaction mixture using ethanol and hexane,
After the first step, the method further comprises adding 6 μl to 24 μl of Fe (CO) ₅ solution to the heated cobalt precursor solution, thereby forming Pt-CoO in the form of a core @ shell nanocube. Forming nanoparticles,
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The cobalt precursor is characterized in that Co (acac) ₂ ,
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The platinum precursor is characterized in that the Pt (acac) ₂ ,
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The solvent of the cobalt precursor solution and the platinum precursor solution is characterized in that 1-octadecene (ODE, 1-octadecene),
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The fatty amine is characterized in that the oleyl amine (OAm, Oleylamine),
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The fatty acid is characterized in that the oleic acid (OA, oleic acid),
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The first step is characterized in that the first heating the cobalt precursor solution, and then the second heating at a higher temperature than the first heating,
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The third step is characterized in that for heating the reaction mixture for 120 minutes to 240 minutes,
Method for producing Pt-CoO nanoparticles.
The method of claim 9,
The third step is characterized in that for heating the reaction mixture to 170 ℃ to 230 ℃,
Method for producing Pt-CoO nanoparticles.
The method according to claim 1 or 2,
The fourth step is characterized in that for cooling the heated reaction mixture to room temperature,
Method for producing Pt-CoO nanoparticles.
delete The method of claim 2,
The Fe (CO) ₅ solution is characterized in that the addition of 6 μl to 24 μl,
Method for producing Pt-CoO nanoparticles.
delete delete delete delete delete delete

Images