Phosphorus-doped graphitic nanoplate with metal introduced, having high specific surface area, and manufacturing method therefor

Abstract

The present invention relates to a phosphorus-doped graphitic nanoplate with a metal introduced, having a high specific surface area, the nanoplate comprising; a phosphorus-doped graphitic nanoplate; and a metal introduced into the phosphorus-doped graphitic nanoplate, wherein the phosphorus-doped graphitic nanoplate is activated. By the introduction of metal nanoparticles into the edge of phosphorus-doped graphitic nanoplate with pores formed through activation, a catalyst capable of effectively preventing aggregation can be provided.

Description

A doped graphitic nanoplate with a metal having a high specific surface area and a method for manufacturing the same

[0001] The present invention relates to a phosphorus-doped graphitic nanoplate having a high surface area and a method for producing the same. Specifically, the present invention relates to a catalyst that is more stable and less expensive than conventional noble metal catalysts, by using phosphorus-doped graphitic nanoplates with a porous structure that have undergone an activation process as a support for a metal catalyst.

[0002] Hydrogen energy, one of the new energy sources that can address global warming, can be produced through water electrolysis without carbon dioxide emissions. While electrolysis can produce high-purity hydrogen without environmental pollution, its low yield and high power consumption have hindered commercialization. Above all, producing hydrogen through water electrolysis requires a good catalyst, which must be affordable, durable, and efficient.

[0003] Platinum, a precious metal primarily used as a catalyst for the hydrogen evolution reaction (HER), offers excellent catalytic activity but is expensive and has poor stability over long periods of operation. Furthermore, its high cost and insufficient reserves hinder its large-scale use. Platinum is particularly susceptible to agglomeration during the hydrogen production process, which can lead to a rapid decline in catalytic activity. Therefore, developing a catalyst that can replace platinum is crucial. While various non-metallic materials are being studied as platinum-replacing catalysts, they remain less active than platinum catalysts. Reducing the platinum content is a key solution to accelerate commercialization.

[0004] Meanwhile, graphene is the basic unit of graphite, a thin film of carbon atoms, just one atom thick. Specifically, it is a two-dimensional planar material in which carbon atoms are covalently bonded in a hexagonal pattern. Graphene possesses excellent thermal and electrical conductivity and possesses exceptional physical and chemical properties.

[0005] Carbon supports offer excellent electrical conductivity, high surface area, and physicochemical stability, but their activity is relatively low. Platinum, with its excellent catalytic activity, suffers from poor stability due to aggregation and insufficient durability. Therefore, it is crucial to develop a support that can prevent aggregation of the supported nanoparticles to maintain catalyst stability.

[0006] (Prior art literature)

[0007] (Patent Document)

[0008] (Patent Document 0001) Korean Patent Registration No. 10-1901223

[0009] The present invention relates to a phosphorus-doped graphitic nanoplate having a metal having a high specific surface area and a method for manufacturing the same, which solves the problems of the above-mentioned prior art, and to a stable and inexpensive catalyst compared to a conventional noble metal catalyst by using a phosphorus-doped graphitic nanoplate having a porous structure produced through an activation process as a catalyst support.

[0010] The metal-doped graphitic nanoplate of the present invention for achieving the above-mentioned technical task comprises a phosphorus-doped graphitic nanoplate; and a metal introduced onto the phosphorus-doped graphitic nanoplate; wherein the phosphorus-doped graphitic nanoplate is characterized in that it is activated.

[0011] Based on 100 parts by weight of the doped graphitic nanoplate into which the metal is introduced, the metal may be present in an amount of 8 to 18 parts by weight, but is not limited thereto.

[0012] Specific surface area is 400 m 2 / g to 1,500 m 2 / g may be, but is not limited to.

[0013] The metal may include, but is not limited to, a metal selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni), and combinations thereof.

[0014] A method for producing a phosphorus-doped graphitic nanoplate into which a metal is introduced comprises the steps of: producing a phosphorus-doped graphitic nanoplate by reacting graphite and a phosphorus source; activating the phosphorus-doped graphitic nanoplate by heat treatment under a carbon dioxide atmosphere; and introducing a metal onto the activated phosphorus-doped graphitic nanoplate.

[0015] The above heat treatment may be performed at 700°C to 1,200°C for 10 minutes to 3 hours, but is not limited thereto.

[0016] The above phosphorus source may include, but is not limited to, a source selected from the group consisting of phosphorus pentoxide (P2O5), phosphine, triethyl phosphate (TEP), phosphoric acid, and combinations thereof.

[0017] The catalyst support comprises phosphorus-doped graphitic nanoplates, wherein the phosphorus-doped graphitic nanoplates are characterized in that they are activated.

[0018] The above-mentioned phosphorus may be doped at the edge of the above-mentioned graphitic nanoplate, but is not limited thereto.

[0019] A catalyst for hydrogen production comprises a phosphorus-doped graphitic nanoplate; and a metal introduced onto the phosphorus-doped graphitic nanoplate; wherein the phosphorus-doped graphitic nanoplate is characterized in that it is activated.

[0020] The above-described problem-solving methods are merely exemplary and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, additional embodiments may be included in the drawings and detailed description of the invention.

[0021] The disclosed technology may have the following effects. However, this does not mean that a particular embodiment must include all or only the following effects, and therefore the scope of the disclosed technology should not be construed as being limited thereby.

[0022] According to the above-described means for solving the problem of the present invention, the phosphorus-doped graphitic nanoplates into which metal is introduced according to the present invention can be used as a catalyst support, and the phosphorus-doped graphitic nanoplates having a hole-like structure created through an activation process can be used as a catalyst support, and a more stable and inexpensive catalyst can be obtained compared to conventional noble metal catalysts.

[0023] The phosphorus of the present invention is formed at the edge of the graphical nanoplate, and acts as an anchor for the metal, thereby allowing the metal to be formed at the edge of the graphical nanoplate. Accordingly, the aggregation of the metal can be reduced.

[0024] Additionally, the difference in electronegativity between phosphorus and carbon allows electrons to move from phosphorus to carbon, and a strong interaction is created to form carbon-phosphorus (CP) bonds, which can generate more defects and promote charge transfer, thereby improving the performance of the catalyst.

[0025] Furthermore, when the metal-doped graphitic nanoplate of the present invention is used as a catalyst for a hydrogen evolution reaction, a catalyst with improved stability can be provided while reducing costs by using a smaller amount of precious metal compared to the conventional one.

[0026] The metal-doped graphitic nanoplates described herein can be applied in a variety of applications, including as catalyst supports, chemical catalysts, energy conversion and storage, and fuel cells. Furthermore, they are inexpensive and can be mass-produced, facilitating cost reductions in the process.

[0027] Figure 1 is a flow chart of a method for manufacturing a metal-doped graphitic nanoplate.

[0028] Figure 2 is a schematic diagram of a method for manufacturing a metal-doped graphitic nanoplate.

[0029] Figure 3 is an FE-SEM (field emission scanning electron microscopy) image of Example 1.

[0030] Figures 4 (a) and (b) are HR-TEM (high-resolution transmission electron microscopy) images of Comparative Example 1.

[0031] Figures 5 (a) and (b) are HR-TEM (high-resolution transmission electron microscopy) images of Example 1.

[0032] Figure 6 (a) is a HR-TEM (high-resolution transmission electron microscopy) image of Example 1, Figure 6 (b) is an element mapping image of carbon, (c) is an element mapping image of oxygen, (d) is an element mapping image of phosphorus, and (e) is an element mapping image of platinum, and the scale bar is 1 um.

[0033] Figure 7 is an XRD (X-Ray diffraction) graph of Example 1.

[0034] Figure 8 is an XPS (X-ray photoelectron spectra) graph of Example 1.

[0035] Figure 9 is a high-resolution XPS (X-ray photoelectron spectra) graph of Pt4f of Example 1.

[0036] Figure 10 is a TGA (Thermogravimetric analysis) graph of Example 1.

[0037] Figure 11 is a polarization curve of Example 1 and Comparative Example 1.

[0038] Figure 12 is a graph showing the overpotential according to the current density of Example 1 and Comparative Example 1.

[0039] Figure 13 is a Tafel plot of Example 1 and Comparative Example 1.

[0040] Figure 14 is a Nyquist plot of Example 1 and Comparative Example 1.

[0041] Figure 15 is a graph showing the current density per scan rate of CV (cyclic voltammetry) of Example 1 and Comparative Example 1.

[0042] Figure 16 is a graph of the electrochemically active surface area (ECSA) of Example 1 and Comparative Example 1.

[0043] Figure 17 shows polarization curves after 1 cycle and 10,000 cycles of Example 1 and Comparative Example 1.

[0044] Figure 18 is a graph showing the overpotential according to the current density after 1 and 10,000 cycles of Example 1 and Comparative Example 1.

[0045] (a) and (b) of FIG. 19 are HR-TEM (high-resolution transmission electron microscopy) images after 10,000 measurements of Comparative Example 1, and (c) and (d) of FIG. 19 are HR-TEM (high-resolution transmission electron microscopy) images after 10,000 measurements of Example 1.

[0046] Figure 20 is a graph showing the specific activity of Example 1 and Comparative Example 1.

[0047] Figure 21 is a graph showing the mass activity of Example 1 and Comparative Example 1.

[0048] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0049] In describing each drawing, similar reference numerals are used to refer to similar components. While terms such as "first," "second," etc. may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another.

[0050] For example, without departing from the scope of the present invention, a first component could be referred to as a second component, and similarly, a second component could also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any one of a plurality of related listed items.

[0051] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0052] Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0053] Throughout this specification, when it is said that a member is located “on,” “above,” “upper,” “lower,” “lower” or “lower” another member, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0054] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0055] The terms "about," "substantially," and the like, as used herein, are used to mean at or near the numerical value when manufacturing and material tolerances inherent to the meanings referred to are presented, and are used to prevent unscrupulous infringers from unfairly exploiting disclosures that contain precise or absolute numerical values ​​to aid understanding of the present disclosure. Furthermore, throughout the present disclosure, the terms "step of ~" or "step of ~" do not mean "step for ~."

[0056] Throughout this specification, the term "combination thereof" included in the expressions in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expressions in the Makushi format, and means including one or more selected from the group consisting of said components.

[0057] Hereinafter, the doped graphitic nanoplates with metal introduced herein will be described in detail with reference to implementation examples, examples, and drawings. However, the present invention is not limited to these implementation examples, examples, and drawings.

[0058]

[0059] The present invention relates to a phosphorus-doped graphitic nanoplate, comprising: a phosphorus-doped graphitic nanoplate; and a metal introduced onto the phosphorus-doped graphitic nanoplate; wherein the phosphorus-doped graphitic nanoplate is an activated, metal-introduced phosphorus-doped graphitic nanoplate.

[0060] Through the above activation, holes are created on the phosphorus-doped graphitic nanoplate, resulting in a holey structure.

[0061] The above phosphorus is doped at the edge of the graphic nanoplate and / or the edge of the hole on the nanoplate.

[0062] The above-mentioned phosphorus acts as an anchor for the metal, thereby allowing the metal to be formed at the edge of the graphical nanoplate and / or the edge of the hole on the nanoplate. Accordingly, when the phosphorus-doped graphical nanoplate into which the metal of the present disclosure is introduced is utilized as a hydrogen catalyst, aggregation of the metal can be prevented.

[0063] The above phosphorus can move from phosphorus to carbon due to the difference in electronegativity between carbons on the graphitic nanoplate, and a strong interaction acts to form carbon-phosphorus (CP) bonds, which generates more defects and promotes charge transfer.

[0064] Based on 100 parts by weight of the doped graphitic nanoplate into which the metal is introduced, the metal may be present in an amount of 8 to 18 parts by weight, but is not limited thereto.

[0065] More preferably, the metal may be present in an amount of 10 to 15 parts by weight, based on 100 parts by weight of the doped graphitic nanoplate into which the metal is introduced, but is not limited thereto.

[0066] Commercially available Pt / C (Premetec Co.) contains 20 wt% platinum. The metal-doped graphitic nanoplates of this invention can reduce costs by using a smaller amount of precious metal than commercially available Pt / C.

[0067] Specific surface area is 400 m 2 / g to 1,500 m 2 / g may be, but is not limited to.

[0068] By activating the above doped graphitic nanoplates, holes are created and the empty spaces facilitate electron transfer between the metal and carbon.

[0069] The pore volume of the doped graphitic nanoplate into which the metal is introduced may be, but is not limited to, 0.5 ml / g to 0.99 ml / g.

[0070] The metal-doped graphitic nanoplates of the present invention have the advantage of a larger specific surface area than the graphitic nanoplates doped with nitrogen.

[0071] The metal may include, but is not limited to, a metal selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni), and combinations thereof.

[0072] Preferably, the metal may be, but is not limited to, platinum (Pt).

[0073] The present invention relates to a method for producing a phosphorus-doped graphitic nanoplate, including the steps of: producing a phosphorus-doped graphitic nanoplate by reacting graphite and a phosphorus source; activating the phosphorus-doped graphitic nanoplate by heat treatment under a carbon dioxide atmosphere; and introducing a metal onto the activated phosphorus-doped graphitic nanoplate.

[0074] Figure 1 is a flow chart of a method for manufacturing a metal-doped graphitic nanoplate.

[0075] Figure 2 is a schematic diagram of a method for manufacturing a metal-doped graphitic nanoplate.

[0076] First, a graphite and a phosphorus source are reacted to produce a phosphorus-doped graphitic nanoplate (S100).

[0077] Specifically, when reacting graphite and phosphorus sources within a reaction vessel, a grinding process, a gas process, etc. can be applied.

[0078] Preferably, the phosphorus-doped graphitic nanoplates may be manufactured by a pulverization process.

[0079] The above pulverization process may be performed by placing graphite and a phosphorus source together with metal balls in a reaction vessel, removing air in the reaction vessel using a vacuum pump, and then pulverizing at a speed of 300 rpm to 600 rpm for 24 to 60 hours, but is not limited thereto.

[0080] The above phosphorus source may include, but is not limited to, a source selected from the group consisting of phosphorus pentoxide (P2O5), phosphine, triethyl phosphate (TEP), phosphoric acid, and combinations thereof.

[0081] Preferably, the above phosphorus source may be phosphorus pentoxide (P2O5).

[0082] The above-described method may further include a step of acid treating the doped graphitic nanoplate.

[0083] The above acid treatment may be performed using an aqueous acid solution having a pH of 3 or lower.

[0084] The above acid may include, but is not limited to, an acid selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, perchloric acid and combinations thereof.

[0085] The aqueous solution of the above acid may be used at a concentration of 0.1 M to 5.0 M, but is not limited thereto.

[0086] The above acid treatment may be performed for, but is not limited to, 12 to 96 hours.

[0087] The above acid treatment can remove metal residues that may occur during the ball mill process.

[0088] The step of freeze-drying the phosphorus-doped graphitic nanoplate subjected to the acid treatment may further be included.

[0089] The above freeze-drying may be performed at a temperature of -100°C to -20°C for 10 to 36 hours, but is not limited thereto.

[0090] As the graphite is pulverized through the pulverization process, the carbon at the edge of the graphical nanoplate becomes charged or in the form of radicals. The charged or radical carbon reacts with the phosphorus source to form a phosphorus-doped graphical nanoplate. During the pulverization process, the carbon at the edge of the graphical nanoplate becomes charged or in the form of radicals, and the carbon reacts with the phosphorus, so that only the edge of the graphical nanoplate is doped with phosphorus.

[0091] Referring to Fig. 2, when P2O5 was used as a phosphorus source, it can be confirmed that phosphorus-doped graphitic nanoplates (PGnP) with P2O5 bonded to the edge of the graphitic nanoplate were formed.

[0092] Next, the above-described phosphorus-doped graphic nanoplate is activated by heat treatment in a carbon dioxide atmosphere (S200).

[0093] The above heat treatment may be performed at 700°C to 1,200°C for 10 minutes to 3 hours, but is not limited thereto.

[0094] If the heat treatment is performed for less than 10 minutes, the phosphorus-doped graphical nanoplate may not be sufficiently activated, and if the heat treatment is performed for more than 3 hours, defects in the phosphorus-doped graphical nanoplate may significantly increase.

[0095] The above temperature may be increased at a rate of 1°C to 20°C per minute, but is not limited thereto.

[0096] The above carbon dioxide may be injected at a rate of 50 ml to 1,000 ml per minute.

[0097] Referring to Figure 2, it can be seen that the activated phosphorus-doped graphical nanoplate has increased defects, and phosphorus is formed not only at the edge of the graphical nanoplate but also at the edge of the defect (hole) within the graphical nanoplate.

[0098] Next, a metal is introduced onto the activated phosphorus-doped graphic nanoplate (S300).

[0099] Specifically, it may be a method of introducing a metal onto the activated phosphorus-doped graphical nanoplate by reacting each of the activated phosphorus-doped graphical nanoplates dispersed in a solvent with a metal precursor.

[0100] It may be possible to introduce metal onto the activated phosphorus-doped graphitic nanoplate by adding a reducing agent to a mixed solution of the activated phosphorus-doped graphitic nanoplate and a metal precursor.

[0101] The reducing agent may be selected from the group consisting of NaBH4, LiAlH4, NaH, CaH2, hydrazine, and combinations thereof, but is not limited thereto.

[0102] The metal precursor may include a metal selected from the group consisting of, but not limited to, platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni), and combinations thereof.

[0103] Preferably, when the metal is platinum, chloroplatinic acid may be used as a platinum precursor, but is not limited thereto.

[0104] The doped graphitic nanoplates with the metal introduced above may be subjected to further steps of filtration, washing and freeze-drying.

[0105] Referring to Figure 2, it can be confirmed that metal (platinum) is formed at the location of the doped phosphorus on the graphic nanoplate.

[0106] Regarding the method for manufacturing a phosphorus-doped graphitic nanoplate having a metal introduced in the present application, a detailed description is omitted for parts that overlap with the phosphorus-doped graphitic nanoplate having a metal introduced in the present application. However, even if the description is omitted, the contents described in the phosphorus-doped graphitic nanoplate having a metal introduced in the present application can be equally applied to the method for manufacturing a phosphorus-doped graphitic nanoplate having a metal introduced.

[0107] The present invention relates to a catalyst support comprising a phosphorus-doped graphitic nanoplate, wherein the phosphorus-doped graphitic nanoplate is activated.

[0108] The above-mentioned phosphorus may be doped at the edge of the graphitic nanoplate and / or the edge of the hole on the nanoplate, but is not limited thereto.

[0109] When a metal catalyst is introduced onto the catalyst support of the present invention, the phosphorus acts as an anchor for the metal, forming the metal at the edge of the graphitic nanoplate, which is the phosphorus location, and / or at the edge of the hole on the nanoplate. Accordingly, when the catalyst support of the present invention is used, the aggregation phenomenon that can occur in conventional metal catalysts can be effectively prevented.

[0110] Regarding the catalyst support of the present invention, a detailed description has been omitted of overlapping parts with the metal-introduced phosphorus-doped graphitic nanoplate of the present invention. However, even if the description has been omitted, the contents described in the metal-introduced phosphorus-doped graphitic nanoplate of the present invention can be equally applied to the catalyst support.

[0111] The present invention relates to a catalyst for hydrogen production, comprising: a phosphorus-doped graphitic nanoplate; and a metal introduced onto the phosphorus-doped graphitic nanoplate; wherein the phosphorus-doped graphitic nanoplate is activated.

[0112] The hydrogen production catalyst of this invention exhibits excellent hydrogen production characteristics, including a low starting voltage, low overvoltage, and a low Tafel value. Furthermore, the hydrogen production catalyst exhibits nearly constant stability even after multiple uses. Furthermore, it achieves better catalytic properties and stability even when using a smaller amount of platinum than commercial platinum catalysts. This suggests that a catalyst with improved performance can be provided while reducing costs.

[0113] Regarding the hydrogen production catalyst of the present invention, detailed descriptions of overlapping parts with the metal-introduced phosphorus-doped graphitic nanoplate of the present invention have been omitted, but even if the descriptions have been omitted, the contents described in the metal-introduced phosphorus-doped graphitic nanoplate of the present invention can be equally applied to the hydrogen production catalyst.

[0114] The present invention will be described in more detail through the following examples; however, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0115] [Example 1]

[0116] First, 80.0 g of graphite (99%, 100 mesh) and phosphorus pentoxide (P2O5) were placed in a grinding vessel together with metal balls (1 kg, 5 mm in diameter). The air inside the grinding vessel was removed using a vacuum pump, and the mixture was ground at a speed of 350 rpm for 48 hours. After grinding, 1 M hydrochloric acid and water were used to remove metal residues from the grinding material, respectively. Then, the mixture was freeze-dried at -60°C for 48 hours to produce phosphorus-doped graphitic nanoplates (PGnP, 98.4 g).

[0117] Next, 10.0 g of the phosphorus-doped graphitic nanoplate (PGnP) was placed in an electric furnace and heat-treated at a temperature of 900°C (10°C / min) for 1 hour in a high-purity (99.99%) carbon dioxide atmosphere (300 ml / min), thereby activating the plate, thereby manufacturing an activated phosphorus-doped graphitic nanoplate (A_PGnP, 5.6 g).

[0118] Next, 1.0 g of the activated phosphorus-doped graphitic nanoplate (A_PGnP) was dispersed in 200 ml of distilled water to prepare a first solution. Chloroplatinic acid (H2PtCl) was used as a platinum precursor. 6· A second solution was prepared by adding 0.4 g of sodium 6H2O and 0.5 g of trisodium citrate to 200 ml of distilled water. After mixing and stirring the first and second solutions, 0.3 g of sodium borohydroxide (NaBH4) was added as a reducing agent, and platinum nanoparticles were formed on the activated phosphorus-doped graphitic nanoplates. The phosphorus-doped graphitic nanoplates with metal introduction were filtered and washed with distilled water several times, and then freeze-dried at -60°C for 48 hours to prepare 0.96 g of phosphorus-doped graphitic nanoplates with metal introduction (Pt / A_PGnP).

[0119]

[0120] [Comparative Example 1]

[0121] As a commercial platinum catalyst, Pt / C (20 wt% Pt on Vulcan XC-72) from Premetek Co. was used.

[0122]

[0123] [evaluation]

[0124] 1. Characterization of metal-doped graphitic nanoplates

[0125] The characteristics of the metal-doped graphitic nanoplates manufactured in the above examples were analyzed, and the results are shown in Figures 3 to 10.

[0126] Figure 3 is an FE-SEM (field emission scanning electron microscopy) image of Example 1.

[0127] According to the results shown in Fig. 3, it can be confirmed that the doped graphitic nanoplates into which the metal of Example 1 was introduced are formed without agglomeration of platinum nanoparticles.

[0128] Figures 4 (a) and (b) are HR-TEM (high-resolution transmission electron microscopy) images of Comparative Example 1.

[0129] Figures 5 (a) and (b) are HR-TEM (high-resolution transmission electron microscopy) images of Example 1.

[0130] According to the results shown in Fig. 4, it can be confirmed that in Comparative Example 1, platinum nanoparticles are evenly distributed on the carbon support.

[0131] On the other hand, according to the results shown in FIG. 5, in Example 1, it can be confirmed that platinum nanoparticles were formed mainly at the edges of the activated phosphorus-doped graphitic nanoplates, where the platinum nanoparticles act as a carbon support. This is because the phosphorus doped at the edges of the graphitic nanoplates acts as an anchor for the platinum nanoparticles.

[0132] Figure 6 (a) is a HR-TEM (high-resolution transmission electron microscopy) image of Example 1, Figure 6 (b) is an element mapping image of carbon, (c) is an element mapping image of oxygen, (d) is an element mapping image of phosphorus, and (e) is an element mapping image of platinum, and the scale bar is 1 um.

[0133] According to the results shown in Fig. 6, it can be confirmed that phosphorus (P) and platinum (Pt) are uniformly distributed on the phosphorus-doped graphical nanoplate into which the metal of Example 1 is introduced, and that the platinum is located at the edge without agglomeration.

[0134] Figure 7 is an XRD (X-Ray diffraction) graph of Example 1.

[0135] Specifically, in FIG. 7, the metal-doped graphitic nanoplate (Pt / A_PGnP) of Example 1 and the activated phosphorus-doped graphitic nanoplate (A_PGnP) are shown together.

[0136] According to the results shown in Fig. 7, Example 1 shows a peak at 25.5° corresponding to the graphitic crystal plane

[0002] , but it can be confirmed that the peak of Pt / A_PGnP is lower than that of A_PGnP. This is because the peak of the platinum nanoparticles is relatively large. In Example 1, Pt / A_PGnP, it can be confirmed that platinum crystal structures corresponding to

[0111] ,

[0200] ,

[0220] , and

[0311] ffc (face-centered cubic) appear at 39.5°, 46.0°, 67.6°, and 815°, respectively. In addition, when the size of the platinum nanoparticle is calculated from the full-width half-maximum (FWHM) at the

[0220] peak using the Scherrer's formula, it has a size of 3.5 nm.

[0137] Figure 8 is an XPS (X-ray photoelectron spectra) graph of Example 1.

[0138] Specifically, in FIG. 8, the metal-doped graphitic nanoplate (Pt / A_PGnP) of Example 1 and the activated phosphorus-doped graphitic nanoplate (A_PGnP) are shown together.

[0139] According to the results shown in Fig. 8, it can be confirmed that C1s, O1s, and P2p peaks appear both before and after the introduction of the metal. It can be confirmed that the metal-doped graphitic nanoplate (Pt / A_PGnP) of Example 1 additionally has a Pt4f peak.

[0140] Figure 9 is a high-resolution XPS (X-ray photoelectron spectra) graph of Pt4f of Example 1.

[0141] Figure 10 is a TGA (Thermogravimetric analysis) graph of Example 1.

[0142] According to the results shown in Fig. 10, the weights of the metal-doped graphitic nanoplates (Pt / A_PGnP) and the activated phosphorus-doped graphitic nanoplates (A_PGnP) introduced at 1,000°C are 20.42 wt% and 7.67 wt%, respectively. When comparing the tar yields, it can be confirmed that the platinum nanoparticles in Example 1 are 12.75 wt%. This is a smaller amount than the 20 wt% of the commercial platinum catalyst in Comparative Example 1.

[0143] Table 1 below shows the BET surface area, pore volume, and pore size of Example 1.

[0144] Surface area (m 2 / g)Pore volume (ml / g)Pore size (nm)A_PGnP925.60.82523.5633Pt / A_PGnP756.40.72930.3857Pt / C2290.06-

[0145] According to the results shown in Table 1, the surface area and pore volume of activated phosphorus-doped graphitic nanoplates (A_PGnP) slightly decrease as platinum is introduced (Pt / A_PGnP). However, these values ​​are significantly higher than those of the commercial platinum catalyst, Pt / C.

[0146]

[0147] 2. Characteristics of metal-doped graphitic nanoplates applied to hydrogen evolution reaction catalysts

[0148] The characteristics of the metal-doped graphitic nanoplates manufactured in the above examples when applied to a hydrogen evolution reaction catalyst were analyzed, and the results are shown in FIGS. 11 to 21.

[0149] The hydrogen evolution reaction was evaluated under 0.5 M H2SO4 conditions in a N2 atmosphere.

[0150] Figure 11 is a polarization curve of Example 1 and Comparative Example 1.

[0151] According to the results shown in Fig. 11, it can be confirmed that the starting electrode for producing hydrogen in both Example 1 and Comparative Example 1 is close to 0 mV.

[0152] Figure 12 is a graph showing the overpotential according to the current density of Example 1 and Comparative Example 1.

[0153] According to the results shown in Fig. 12, the platinum content of Example 1 is 12.75%, which is lower than 20% of Comparative Example 1, but the overvoltage is similar, or in particular, the current density is 50 mA / cm. 2 It can be seen that it shows a lower overvoltage.

[0154] Figure 13 is a Tafel plot of Example 1 and Comparative Example 1.

[0155] According to the results shown in Fig. 13, Example 1 has a lower Tafel slope value of 31.09 mV / dec, while Comparative Example 1 has a lower Tafel slope value of 32.73 mV / dec. This means that Example 1 has a higher hydrogen production capacity than Comparative Example 1.

[0156] Figure 14 is a Nyquist plot of Example 1 and Comparative Example 1.

[0157] According to the results shown in Fig. 14, it can be confirmed that the size of the semicircle drawn by the graph in the Nyquist plot is smaller for Example 1 than for Comparative Example 1. This means that the hydrogen generation reactivity of Example 1 is higher. In addition, EIS (Electrochemical impedance spectroscopy) shows that Example 1 has a value of 6.684Ωcm. 2 Comparative Example 1 (6.684Ωcm) 2 ) is almost the same.

[0158] Figure 15 is a graph showing the current density per scan rate of CV (cyclic voltammetry) of Example 1 and Comparative Example 1.

[0159] According to the results shown in Fig. 15, the double-layer capacitance (C dl ) is 114.46 mF / cm in Example 1 2 And comparative example 1 is 24.29 mF / cm 2 am.

[0160] Figure 16 is a graph of the electrochemically active surface area (ECSA) of Example 1 and Comparative Example 1.

[0161] According to the results shown in Figures 15 and 16, it can be confirmed that the electrochemically active surface area (ECSA) of Example 1 is significantly higher than that of Comparative Example 1. This suggests that the activity can be further increased when used as a hydrogen production catalyst.

[0162] To confirm the stability of Example 1 and Comparative Example 1, CV (Cyclic Voltammetry) was measured at a rate of 200 mV / s, and changes after 10,000 measurements were observed.

[0163] Figure 17 shows polarization curves after 1 cycle and 10,000 cycles of Example 1 and Comparative Example 1.

[0164] According to the results shown in Fig. 17, the starting point of the polarization curve of Comparative Example 1 changed by -8 mV after 10,000 measurements. On the other hand, it can be confirmed that the starting point of the polarization curve of Example 1 changed by -1 mV after 10,000 measurements. In other words, it can be confirmed that the metal-introduced phosphorus-doped graphical nanoplate of Example 1 has a starting electrode that is almost constant even after repeated tests, and in particular, it has achieved more stable catalytic properties as it shows less change than Comparative Example 1.

[0165] Figure 18 is a graph showing the overpotential according to the current density after 1 and 10,000 cycles of Example 1 and Comparative Example 1.

[0166] According to the results shown in Fig. 18, it can be confirmed that the overvoltage of Comparative Example 1 increased significantly after 10,000 measurements. However, the overvoltage of Example 1 did not increase significantly even after 10,000 measurements, and the overvoltage was 10 to 50 mA / cm. 2 It can be confirmed that both overvoltages measured at the current density are lower than in Comparative Example 1.

[0167] (a) and (b) of FIG. 19 are HR-TEM (high-resolution transmission electron microscopy) images after 10,000 measurements of Comparative Example 1, and (c) and (d) of FIG. 19 are HR-TEM (high-resolution transmission electron microscopy) images after 10,000 measurements of Example 1.

[0168] According to the results shown in Fig. 19, compared to Figs. 4 and 5, it can be confirmed that in Comparative Example 1, many platinum nanoparticles have fallen off, whereas in Example 1, the platinum nanoparticles remain almost intact even after 10,000 measurements.

[0169] Figure 20 is a graph showing the specific activity of Example 1 and Comparative Example 1.

[0170] Figure 21 is a graph showing the mass activity of Example 1 and Comparative Example 1.

[0171] Mass activity represents the current value according to the amount of metal on the catalyst, and specific activity represents the current value according to the electrochemical surface area of ​​the catalyst. According to the results shown in Figures 20 and 21, it can be confirmed that the starting voltage of Example 1 is lower than that of Comparative Example 1. This means that the catalytic activity of Example 1 is higher even when the same amount of platinum nanoparticles is present.

[0172] It can be confirmed that the phosphorus-doped graphitic nanoplates with the metal introduced in the present invention exhibit similar or higher oxidation activity than the commercial platinum catalyst as a comparative example, despite having a lower platinum content. In addition, they show significantly higher stability. From this, it can be confirmed that while the commercial platinum catalyst causes aggregation upon repeated use, the phosphorus located at the edge of the phosphorus-doped graphitic nanoplates with the metal introduced in the present invention acts as an anchor for the platinum, effectively preventing aggregation and fixing the platinum.

[0173]

[0174] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0175] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. Graphitic nanoplates doped with phosphorus; and The above metal is introduced onto the doped graphitic nanoplate; The above phosphorus-doped graphitic nanoplate is an activated, metal-introduced phosphorus-doped graphitic nanoplate.

2. In paragraph 1, A metal-doped graphitic nanoplate, wherein the metal is introduced in an amount of 8 to 18 parts by weight, based on 100 parts by weight of the metal-doped graphitic nanoplate.

3. In paragraph 1, Specific surface area is 400 m 2 / g to 1,500 m 2 / g, metal-doped graphitic nanoplates.

4. In paragraph 1, A metal-doped graphitic nanoplate, wherein the metal is selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni) and combinations thereof.

5. A step of manufacturing a phosphorus-doped graphitic nanoplate by reacting graphite and a phosphorus source; A step of activating the above-mentioned phosphorus-doped graphitic nanoplate by heat treatment under a carbon dioxide atmosphere; and A method for manufacturing a metal-introduced phosphorus-doped graphitic nanoplate, comprising the step of introducing a metal onto the activated phosphorus-doped graphitic nanoplate.

6. In paragraph 5, A method for manufacturing a metal-doped graphitic nanoplate, wherein the above heat treatment is performed at 700°C to 1,200°C for 10 minutes to 3 hours.

7. In paragraph 5, A method for producing a metal-doped graphitic nanoplate, wherein the above phosphorus source comprises a metal selected from the group consisting of phosphorus pentoxide (P2O5), phosphine, triethyl phosphate (TEP), phosphoric acid, and combinations thereof.

8. Contains a graphitic nanoplate doped with phosphorus, The above-mentioned graphitic nanoplates doped with phosphorus are activated catalyst carriers.

9. In paragraph 8, The above catalyst support is doped at the edge of the above graphitic nanoplate.

10. Graphitic nanoplates doped with phosphorus; and The above metal is introduced onto the doped graphitic nanoplate; The above-mentioned phosphorus-doped graphitic nanoplate is an activated catalyst for hydrogen production.

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