Maxine nanosheet hybrid composite, manufacturing method thereof, and electrochemical catalyst including same

Abstract

An embodiment may provide a metal-positive ion-MXene nanosheet hybrid composite. According to the embodiment, by providing a hybrid composite composed of metal particles / positive ions / MXene nanosheets, there is a feature that may provide a hydrogen evolution reaction catalyst having excellent electrochemical performance with a high current value and low overvoltage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the priority of Korean Patent Application Nos. 10-2024-0015194 filed on Jan. 31, 2024 and 10-2024-0184897 filed on Dec. 12, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.BACKGROUND

[0002] The disclosure relates to a MXene nanosheet hybrid composite, a manufacturing method thereof, and an electrochemical catalyst including the same, and more specifically, to a hybrid composite composed of metal-positive ion-MXene, a manufacturing method thereof, and an electrochemical catalyst for hydrogen generation reaction including the same.

[0003] Renewable energy sources such as solar and wind power are becoming increasingly widespread in response to the increasing demand for sustainable and pollutant-free energy sources, but they have limitations such as intermittency and regional dependency. Hydrogen energy is gaining attention as an eco-friendly energy source that may replace fossil fuels due to its abundance of resources and the fact that it does not emit harmful substances.

[0004] The representative method of producing hydrogen is water electrolysis. Water electrolysis is the most promising method for producing high-purity hydrogen and oxygen through the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively.

[0005] Water electrolysis catalysts mainly use precious metals such as platinum, ruthenium, and iridium, which are considered ideal electrocatalysts for OER and HER in alkaline solutions. However, high cost, low stability, and depletion of precious metals limit large-scale production. To overcome these shortcomings, non-noble metal catalyst materials such as transition metal-based oxides, phosphates, selenides, sulfides, nitrides, borides, carbides, organometallic compounds, and hydroxides are used to evaluate HER and OER performances, but they still have limitations such as low current values and high overvoltages.

[0006] MXene is a type of two-dimensional carbide material that has very high electrical and thermal conductivity and may be easily combined with various metal compounds. MXene is a material that can be utilized in various fields such as semiconductors, electronic devices, and sensors, due to these characteristics.

[0007] MXene has a high surface area, so it is effective for adsorption and catalytic applications, and can act as a catalyst in various chemical reactions.RELATED ART DOCUMENTPatent Document(Patent document 0001) KR 10-2022-0168203 ASUMMARY

[0009] An aspect of the disclosure is to provide a catalyst for hydrogen generation reaction having improved stability in the hydrogen generation reaction of water electrolysis and improved catalytic performance with a high current value and low overvoltage.

[0010] The aspect of the disclosure is not limited to that mentioned above, and other aspects not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] An embodiment of the disclosure provides a MXene nanosheet hybrid composite, including: an Mn+1AnTx MXene nanosheet; positive ions stacked on the Mn+1AnTx MXene nanosheet; and metal particles uniformly distributed on the Mn+1AnTx MXene nanosheet, wherein M is at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, A is carbon (C), nitrogen (N) or a combination thereof, Tx is oxide (O), epoxide, hydroxide (OH), alkoxide having 1 to 5 carbon atoms, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof, and n is 1, 2 or 3.

[0012] In an embodiment of the disclosure, the positive ions may be selected from the group consisting of H+, Li+, Na+, K+, Rb+, Cs+, Al3+, V3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Y3+.

[0013] In an embodiment of the disclosure, the metal particles include at least one of ruthenium (Ru), platinum (Pt), gold (Au), rhodium (Rh), palladium (Pd), or iridium (Ir).

[0014] In an embodiment of the disclosure, the MXene nanosheet hybrid composite may exhibit a porous two-dimensional nanosheet form.

[0015] Another embodiment of the disclosure provides a method for manufacturing a MXene nanosheet hybrid composite, the method including: preparing a Mn+1AnTx MXene nanosheet; exfoliating the Mn+1AnTx MXene nanosheet and stacking the Mn+1AnTx MXene nanosheets by positive ions; and manufacturing a MXene nanosheet hybrid composite by reacting the restacked Mn+1AnTx MXene nanosheet on which the positive ions are attached with a metal precursor solution, wherein M is at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, A is carbon (C), nitrogen (N) or a combination thereof, Tx is oxide (O), epoxide, hydroxide (OH), alkoxide having 1 to 5 carbon atoms, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof, and n is 1, 2 or 3.

[0016] In an embodiment of the disclosure, the preparing of the Mn+1AnTx MXene nanosheet is performed by removing a B layer from an inorganic compound having an Mn+1BAn composition, and the B is at least one selected from Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl and Pb.

[0017] In an embodiment of the disclosure, the positive ions may be selected from the group consisting of H+, Li+, Na+, K+, Rb+, Cs+, Al3+, V3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Y3+.

[0018] In an embodiment of the disclosure, the metal particles include at least one of ruthenium (Ru), platinum (Pt), gold (Au), rhodium (Rh), palladium (Pd), or iridium (Ir).

[0019] In an embodiment of the disclosure, in the exfoliating of the Mn+1AnTx MXene nanosheet and in the stacking of the positive ions, the exfoliated Mn+1AnTx MXene nanosheet may have a negative charge on the surface, and thus stacking may be made while an interlayer distance is controlled through electrostatic attraction with the positive ions.

[0020] Another embodiment of the disclosure provides an electrochemical catalyst, including said MXene nanosheet hybrid composite.

[0021] According to an embodiment of the disclosure, a metal-positive ion-MXene nanosheet hybrid composite may be manufactured, and a hydrogen generation reaction catalyst including the same may be manufactured to improve electrochemical performance by obtaining a high current value and a low overvoltage, thereby improving the hydrogen generation reaction catalyst performance.

[0022] The effects of the disclosure are not limited to the effects described above, and should be understood to include all effects that are inferable from the configuration of the disclosure described in the detailed description or claims of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0024] FIG. 1 is an XRD pattern of a Pd-positive ion-MXene hybrid composite according to an embodiment of the disclosure;

[0025] FIG. 2A is an FE-SEM image of a PdMX hybrid composite according to an embodiment of the disclosure;

[0026] FIG. 2B is an FE-SEM image of a PdHMX hybrid composite according to an embodiment of the disclosure;

[0027] FIG. 2C is an FE-SEM image of a PdLMX hybrid composite according to an embodiment of the disclosure;

[0028] FIG. 2D is an FE-SEM image of a PdNMX hybrid composite according to an embodiment of the disclosure;

[0029] FIG. 2E is a FE-SEM image of a PdKMX hybrid composite according to an embodiment of the disclosure;

[0030] FIG. 3A is a STEM image of a PdKMX hybrid composite according to an embodiment of the disclosure;

[0031] FIG. 3B is an element mapping image of a PdKMX hybrid composite according to an embodiment of the disclosure;

[0032] FIG. 4A is a Ti K-edge XANES analysis result of a hybrid composite of a Pd-positive ion-MXene hybrid composite according to an embodiment of the disclosure;

[0033] FIG. 4B is a Pd LIII-edge XANES analysis result of a Pd-positive ion-MXene hybrid composite according to an embodiment of the disclosure;

[0034] FIG. 5A is a Pd LIII-EXAFS analysis result of a Pd foil;

[0035] FIG. 5B is a Pd LIII-EXAFS analysis result of a hybrid composite of a PdHMX hybrid composite according to an embodiment of the disclosure;

[0036] FIG. 5C is a Pd LIII-EXAFS analysis result of a hybrid composite of a PdLMX hybrid composite according to an embodiment of the disclosure;

[0037] FIG. 5D is a Pd LIII-EXAFS analysis result of a hybrid composite of a PdNMX hybrid composite according to an embodiment of the disclosure;

[0038] FIG. 5E is a Pd LIII-EXAFS analysis result of a hybrid composite of a PdKMX hybrid composite according to an embodiment of the disclosure;

[0039] FIG. 6A is surface area measurement data of a precursor (KMX) before hybridization with PdKMX according to an embodiment of the disclosure;

[0040] FIG. 6B is pore volume measurement data of a precursor (KMX) before hybridization with PdKMX according to an embodiment of the disclosure;

[0041] FIG. 7A is hydrogen generation catalyst data of a PdKMX hybrid composite according to an embodiment of the disclosure;

[0042] FIG. 7B is overvoltage data of a PdKMX hybrid composite according to an embodiment of the disclosure; and

[0043] FIG. 7C is stability data of a PdKMX hybrid composite according to an embodiment of the disclosure.DETAILED DESCRIPTION

[0044] Hereinafter, the disclosure will be described with reference to the accompanying drawings. However, the disclosure may be implemented in various different forms, and therefore is not limited to the embodiments described herein. In addition, in order to clearly describe the disclosure in the drawings, parts that are not related to the description are omitted, and similar parts are given similar drawing reference numerals throughout the specification.

[0045] In the entire specification, when a part is said to be “connected (linked, contacted, coupled)” to another part, this includes not only the case where it is “directly connected” but also the case where it is “indirectly connected” with another member in between. In addition, when a part is said to “include” a certain component, this does not mean that other components are excluded unless otherwise specifically stated, but that other components may be additionally provided.

[0046] The terms used in this specification are used only to describe specific embodiments and are not intended to limit the disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, the terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0047] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0048] The terms used in this specification are defined as follows:

[0049] “MX” means MXene.

[0050] “PdHMX” means Pd—H+-MX hybrid composite.

[0051] “PdLMX” means Pd—Li+-MX hybrid composite.

[0052] “PdNMX” means Pd—Na+-MX hybrid composite.

[0053] “PdKMX” means Pd—K+-MX hybrid composite.

[0054] A MXene nanosheet hybrid composite according to an embodiment of the disclosure will be described.

[0055] A MXene nanosheet hybrid composite according to an embodiment of the disclosure includes: an Mn+1AnTx MXene nanosheet; positive ions stacked on the Mn+1AnTx MXene nanosheet; and metal particles uniformly distributed on the Mn+1AnTx MXene nanosheet.

[0056] The M is at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W.

[0057] The A is carbon (C), nitrogen (N), or a combination thereof, and Tx is oxide (O), epoxide, hydroxide (OH), alkoxide having 1 to 5 carbon atoms, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof.

[0058] The n may be 1, 2 or 3.

[0059] The positive ion may be selected from the group consisting of H+, Li+, Na+, K+, Rb+, Cs+, Al3+, V3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Y3+.

[0060] The metal particles may be metals that may be used as conventional noble metal catalysts, and may maximize catalytic activity by forming a hybrid composite with positive ions and MXene. For example, the metal particles may include at least one of ruthenium (Ru), platinum (Pt), gold (Au), rhodium (Rh), palladium (Pd), or iridium (Ir).

[0061] The MXene nanosheet hybrid composite may exhibit a porous two-dimensional nanosheet form.

[0062] Next, a method for manufacturing a MXene nanosheet hybrid composite according to another embodiment of the disclosure will be described.

[0063] A method for manufacturing a MXene nanosheet hybrid composite according to an embodiment of the disclosure includes: preparing a Mn+1AnTx MXene nanosheet (S100); exfoliating the Mn+1AnTx MXene nanosheet and stacking positive ions (S200); and manufacturing a MXene nanosheet hybrid composite by reacting the Mn+1AnTx MXene nanosheet on which the positive ions are stacked with a metal precursor solution (S300).

[0064] Here, M may be at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, A is carbon (C), nitrogen (N) or a combination thereof, Tx is oxide (O), epoxide, hydroxide (OH), alkoxide having 1 to 5 carbon atoms, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof, and n may be 1, 2 or 3.

[0065] The first is preparing an Mn+1AnTx MXene nanosheet (S100).

[0066] The preparing of the Mn+1AnTx MXene nanosheet (S100) is performed by removing a B layer from an inorganic compound having an Mn+1BAn composition, and the B may be at least one selected from Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl, and Pb.

[0067] The inorganic compound having an Mn+1AnTx composition is a layered hexagonal carbide, nitride, or carbonitride called a “MAX phase.” The MAX phase has a structure in which a carbide and / or nitride layer (a layer having an Mn+1AnTx composition, a MXene layer) and a B atomic layer are alternately arranged in a two-dimensional manner in which one B atom is positioned inside six transition metal (M) atoms arranged in a regular octahedral shape. The MXene layer and the B atomic layer are stacked by ionic metal bonding. The B atomic layer is selectively removed from this MAX phase and then to manufacture a MXene nanosheet of which the surface is substantially modified with functional groups.

[0068] At this time, the removal of the B atomic layer may be performed by reaction with a strong acid in an etching manner.

[0069] The next is exfoliating the Mn+1AnTx MXene nanosheet and stacking positive ions (S200).

[0070] The positive ion may be selected from the group consisting of H+, Li+, Na+, K+, Rb+, Cs+, Al3+, V3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Y3+.

[0071] In the exfoliating of the Mn+1AnTx MXene nanosheet and the stacking of the Mn+1AnTx MXene nanosheets by positive ions, the exfoliated Mn+1AnTx MXene nanosheet has a negative charge on its surface, so that the interlayer distance may be controlled and stacked through electrostatic attraction with the positive ions.

[0072] The next is manufacturing a MXene nanosheet hybrid composite by reacting the Mn+1AnTX MXene nanosheet on which the positive ions are attached with a metal precursor solution (S300).

[0073] The metal may include at least one of ruthenium (Ru), platinum (Pt), gold (Au), rhodium (Rh), palladium (Pd), or iridium (Ir).

[0074] At this time, the reaction may be performed at room temperature, and there is no special limitation.

[0075] Hereinafter, an electrochemical catalyst according to another embodiment of the disclosure will be described.

[0076] An electrochemical catalyst according to an embodiment of the disclosure may include the MXene nanosheet hybrid composite.

[0077] Hereinafter, manufacturing examples and experimental examples of the disclosure will be described in detail.Manufacturing ExampleFirst Step: Synthesis of Precursor Nanosheets

[0078] The precursor Ti3C2Tx (MXene) nanosheets were synthesized using a method as below. First, to etch the Al between layers, 1 g Ti3AlC2 was added to 20 mL of a mixed solution (12 mL 12 M HCl, 6 mL water, 2 mL 50 wt % HF) and stirred at 35° C. for 24 h. The reacted sample was washed with an excess of water until the pH became −6. The obtained sample was reacted with 50 mL of 0.5 M LiCl for 24 h. After the reaction, the excess was washed again with water and the supernatant was taken at the 4th to 8th wash.Second Step: Synthesis of Pd-Laminated Inorganic Nanosheets

[0079] Since the exfoliated Ti3C2Tx has a negative charge on the surface, re-laminated nanosheets with controlled interlayer distances may be synthesized through positive ions and electrostatic forces. The synthesized Ti3C2Tx colloids were laminated with four types of positive ions, H+, Li+, Na+, and K+, respectively. The MXene nanosheets laminated with positive ions were stirred with a PdCl2 solution (2.0 wt % Pd) at 25° C. to synthesize Pd-positive ion-MXene hybrid composites. The synthesized hybrid composites were named PdHMX, PdLMX, PdNMX, and PdKMX, respectively, according to the type of positive ion.Third Step: Hydrogen Evolution Reaction (HER) Performance Measurement

[0080] 1.6 mg of the synthesized material is added to 380 μl of triple-distilled water and 20 μl of 5 wt % Nafion solution and dispersed using ultrasonication for 1 hour. 50 μl of the dispersed solution is sampled on carbon paper (0.5 cm×0.5 cm) and used as a working electrode. An SCE electrode is used as a reference electrode and graphite rod is used as a counter electrode. 0.5 M H2SO4 solution saturated with nitrogen gas is used as an electrolyte and the hydrogen evolution reaction catalytic activity is tested at a scan rate of 5 mV / s.<Experimental Example 1> Morphological Characteristics

[0081] FIG. 1 is an XRD pattern of a Pd-positive ion-MXene hybrid composite according to the disclosure.

[0082] Referring to FIG. 1, all of the synthesized hybrid composites showed a typical XRD pattern resulting from MXene lamination, and it was confirmed that there was no peak of Pd in any material. This is because Pd exists in a very small amount and the particles were formed in a very small size, so it cannot be observed in the XRD pattern.

[0083] FIG. 2A is an FE-SEM image of a PdMX hybrid composite according to an embodiment of the disclosure, and FIG. 2B is an FE-SEM image of a PdHMX hybrid composite according to an embodiment of the disclosure.

[0084] Specifically, FIGS. 2A to 2E disclose FE-SEM images of PdMX, PdHMX, PdLMX, PdNMX, and PdKMX hybrid composites, respectively.

[0085] Referring to FIGS. 2A to 2E above, it is possible to confirm that all of the synthesized hybrid composites have a porous two-dimensional nanosheet shape.

[0086] FIG. 3A is a STEM image of a PdKMX hybrid composite according to the disclosure, and FIG. 3B is an element mapping image of a PdKMX hybrid composite according to the disclosure.

[0087] Referring to FIG. 3A, it can be confirmed that small Pd particles are uniformly placed on the nanosheets laminated with K+ ions. This can be seen from the element mapping image of FIG. 3B that Ti, Pd, C, K, and O are evenly present in PdKMX, indicating that Pd particles are very uniformly present in the hybrid composite.

[0088] FIG. 4A is the Ti K-edge XANES analysis result of the hybrid composite of the Pd-positive ion-MXene hybrid composite according to an embodiment of the disclosure, and FIG. 4B is the Pd LIII-edge XANES analysis result of the Pd-positive ion-MXene hybrid composite according to an embodiment of the disclosure.

[0089] Referring to FIG. 4A, it was confirmed through the Ti K-edge XANES analysis that the MXene structure was well maintained without structural deformation even after Pd hybridization, and it was confirmed through the Pd LIII-edge XANES of FIG. 4B that all Pds also had a Pd metal structure.

[0090] FIGS. 5A to 5E show the Pd LIII-EXAFS analysis results of the Pd-positive ion-MXene hybrid composite according to the disclosure, and Table 1 shows the Pd LIII-EXAFS fitting results.TABLE 1Coordinationσ2 MaterialCouplingnumberR (Å)E0 (eV)(Å2 × 10−3)PdHMXPd-Pd6.502.753.995.53PdLMXPd-Pd6.352.753.805.90PdNMXPd-Pd6.252.753.875.83PdKMXPd-Pd5.962.753.906.35Bulk PdPd-Pd122.754.555.31

[0091] As can be seen from the analysis results in FIGS. 5A to 5E and Table 1, the coordination number of Pd hybridized to the MXene nanosheets on which Pd is laminated is much smaller than 12, compared to bulk Pd, which has a coordination number of 12. This low Pd coordination number indicates that Pd exists as very small particles in the Pd-MXene hybrid composite. In addition, among the hybrid composites layered with various positive ions, the PdKMX layered with K+ ions has the smallest Pd coordination number, indicating that Pd and K+-MXene are strongly coupled.

[0092] FIG. 6 shows the surface area (A) and pore volume (B) measurement data of KMX and PdKMX. As seen in FIGS. 6A and 6B, it is possible to confirm that KMX before hybridization has a surface area of 16.8 m2 / g and a pore volume of 0.181 cm3 / g, and hybridized PdKMX has a surface area of 30.1 m2 / g and a pore volume of 0.249 cm3 / g. These results show that the interlayer distance of KMX widened and the stacking thickness became thinner due to hybridization with Pd.<Experimental Example 2> Electrochemical Characteristics

[0093] FIG. 7 shows (A) hydrogen generation catalyst data, (B) overvoltage data, and (C) stability data of the Pd-positive ion-MXene hybrid composite according to the disclosure.

[0094] FIG. 7A shows hydrogen generation catalyst activity data of the synthesized hybrid composite. From FIG. 7B, it can be seen that among the various hybrid composites synthesized, PdKMX has the lowest overvoltage at 10 mA / cm2 current. Even though the synthesized hybrid composite contained about 1 wt % of Pd (ICP result), its performance is comparable to that of the currently commercialized platinum catalyst. In addition, as shown in FIG. 7C, it can be seen that the voltage is maintained constant when the current is applied for 60 hours, indicating that PdKMX has excellent stability.

[0095] The description of the disclosure is for illustrative purposes, and those skilled in the art will understand that it can be easily modified into other specific forms without changing the technical idea or essential features of the disclosure. Therefore, the embodiments described above should be understood as being exemplary in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and likewise, components described as distributed may be implemented in a combined form.

[0096] The scope of the disclosure is indicated by the following claims, 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 disclosure.

Claims

1. A MXene nanosheet hybrid composite, comprising:a Mn+1AnTx MXene nanosheet;positive ions stacked on the Mn+1AnTx MXene nanosheet; andmetal particles uniformly distributed on the Mn+1AnTx MXene nanosheet,whereinthe M is at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W,the A is carbon (C), nitrogen (N) or a combination thereof,the Tx is oxide (O), epoxide, hydroxide (OH), alkoxide having a number of carbon atoms in a range of 1 to 5, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof, andthe n is 1, 2 or 3.

2. The MXene nanosheet hybrid composite of claim 1, whereineach of the positive ions is selected from a group consisting of H+, Li+, Na+, K+, Rb+, Cs+, Al3+, V3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Y3+.

3. The MXene nanosheet hybrid composite of claim 1, whereinthe metal particles include at least one of ruthenium (Ru), platinum (Pt), gold (Au), rhodium (Rh), palladium (Pd), or iridium (Ir).

4. The MXene nanosheet hybrid composite of claim 1, whereinthe MXene nanosheet hybrid composite exhibits a porous two-dimensional nanosheet form.

5. A method for manufacturing a MXene nanosheet hybrid composite, the method comprising:preparing an Mn+1AnTx MXene nanosheet;exfoliating the Mn+1AnTx MXene nanosheet and stacking positive ions; andmanufacturing a MXene nanosheet hybrid composite by reacting the Mn+1AnTx MXene nanosheet, where the positive ions are stacked, with a metal precursor solution,whereinthe M is at least one transition metal selected from Sc, Y, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W,the A is carbon (C), nitrogen (N) or a combination thereof,the Tx is oxide (O), epoxide, hydroxide (OH), alkoxide having a number of carbon atoms in a range of 1 to 5, fluoride (F), chloride (Cl), bromide (Br), iodide (I), or a combination thereof, andthe n is 1, 2 or 3.

6. The method of claim 5, whereinthe preparing the Mn+1AnTx MXene nanosheet is performed by removing a B layer from an inorganic compound having an Mn+1BAn composition, andthe B layer includes at least one selected from Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl and Pb.

7. The method of claim 5, whereineach of the positive ions is selected from a group consisting of H+, Li+, Na+, K+, Rb+, Cs+, Al3+, V3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Y3+.

8. The method of claim 5, whereinthe metal precursor solution includes at least one of ruthenium (Ru), platinum (Pt), gold (Au), rhodium (Rh), palladium (Pd); or iridium (Ir).

9. The method of claim 5, whereinin the exfoliating the Mn+1AnTx MXene nanosheet and the stacking the positive ions,the Mn+1AnTx MXene nanosheet has a negative charge on at least one surface, allowing the stacking to be made while an interlayer distance is controlled through electrostatic attraction with the positive ions.

10. An electrochemical catalyst, comprising the MXene nanosheet hybrid composite according to claim 1.

Images