KR20210036087A - The catalysis including transition metal dichalcogenides nanoribbons and methode for the same - Google Patents

Abstract

The present invention relates to: a catalyst comprising a 1T'-phase monolayer transition metal dichalcogenide nanoribbon; and a method for manufacturing a nanoribbon, comprising a step of manufacturing a 1T'-phase transition metal dichalcogenide nanoribbon by bringing a 1T'-phase transition metal dichalcogenide nanosheet into contact with reactive ions.

Description

The catalysis including transition metal dichalcogenides nanoribbons and methode for the same}

The present invention relates to a catalyst comprising a transition metal-dichalcogenide nanoribbon and a method for preparing the same, and in detail, a catalyst comprising a transition metal-dichalcogenide nanoribbon having excellent catalytic activity comparable to that of a noble metal platinum catalyst And a manufacturing method thereof.

Noble metal catalysts such as platinum (Pt) used in conventional hydrogen evolution reactions (HER) are not soluble in acidic solutions and have the advantage of showing high catalytic activity, but their reserves are limited and they are expensive because they are expensive. Difficulty in mass production of hydrogen. In order to solve this problem, studies on non-precious metal catalysts using transition metal-dichalcogenide have been continuously reported. In order for these transition metal-dichalcogenides to have excellent HER catalytic activity, the active sites of hydrogen generation reactions must be large. Therefore, there are more active sites in the case of a nanostructure composed of several layers than in the bulk state. It is known to have high HER catalytic activity when exposed. In this regard, Korean Patent Registration No. 10-1866865 provides a transition metal-dichalcogenide nanosheet from which a bulk transition metal-dichalcogenide is peeled by using a chemical lithium intercalation (Li intercalation). There is a disadvantage of showing lower HER catalytic activity compared to the catalyst.

Korean Patent Registration No. 10-1866865

It is an object of the present invention to provide a catalyst comprising a transition metal-dichalcogenide nanoribbon having a well-defined shape and improved reactivity.

Another object of the present invention is to provide a catalyst comprising a transition metal-dichalcogenide nanoribbon having improved catalytic activity.

Another object of the present invention is to provide a method for producing a transition metal-dichalcogenide nanoribbon, which is advantageous for commercialization, capable of nanoribbonizing most of the raw materials introduced in a simple process under relaxed conditions.

Another object of the present invention is to provide a method for producing a transition metal-dichalcogenide nanoribbon having a well-defined shape and improved reactivity.

The nanoribbon according to the present invention is a catalyst including a distorted 1T, 1T' monolayer transition metal dichalcogenide nanoribbon.

The catalyst including nanoribbons according to an embodiment of the present invention may have an intensity of 0.1 or less based on the intensity of the _{A 1g} peak or no ^{E 1} _{2g peak in the Raman spectrum.}

In the catalyst including nanoribbons according to an embodiment of the present invention, the edge density of the nanoribbons may be ^{10 15} pieces/cm ^{2 or more.}

The catalyst including nanoribbons according to an embodiment of the present invention may have an average width of 20 to 50 nm, and may have a strip shape having an average length of 100 to 800 nm.

In the catalyst including a nanoribbon according to an embodiment of the present invention, the transition metal of the transition metal-dichalcogenide may be a group VIB transition metal.

In the catalyst including a nanoribbon according to an embodiment of the present invention, the chalcogen of the transition metal-dichalcogenide may be selected from one or two or more of S, Se, and Te.

The present invention includes a hydrogen evolution reaction (HER) catalyst including a catalyst including the above-described nanoribbons.

The present invention includes a catalyst support including a catalyst including the nanoribbons described above.

The present invention includes a method for generating electrochemical hydrogen using a catalyst including the nanoribbons described above.

The present invention includes a distorted 1T (1T') monolayer transition metal dichalcogenide nanoribbon.

The present invention includes the method for manufacturing the above-described nanoribbon.

The manufacturing method of the nanoribbon according to the present invention is a single-layer transition metal-dichalcogenide nanoribbon of a 1T' phase by contacting a distorted 1T phase (distorted 1T, 1T') transition metal-dichalcogenide nanosheet with reactive ions. It includes; unziping step of manufacturing a.

In the method of manufacturing a nanoribbon according to an embodiment of the present invention, the contact may be performed by mixing with an unziping liquid containing reactive ions.

In the method for manufacturing a nanoribbon according to an embodiment of the present invention, the reactive ions may be one or more ions selected from oxygen ions, nitrogen ions, or phosphorus ions.

In the method of manufacturing a nanoribbon according to an embodiment of the present invention, ultrasonic waves may be applied to the unziping liquid mixed with the nanosheets.

In the method of manufacturing a nanoribbon according to an embodiment of the present invention, before contact, an alkali metal or alkaline earth metal ion is inserted between the bulk transition metal-dichalcogenide layer to prepare a transition metal-dichalcogenide interlayer compound. The ion implantation step; may be further performed.

The present invention includes a 1T'-phase single-layer transition metal-dichalcogenide nanoribbon prepared by the above-described manufacturing method.

Since the transition metal-dichalcogenide nanoribbon according to the present invention is a single-layer transition metal-dichalcogenide nanoribbon of a distorted 1T phase, the edge site density is remarkably improved to have excellent catalytic activity and high hydrogen conversion efficiency. There is an advantage.

The method of manufacturing a transition metal-dichalcogenide nanoribbon according to the present invention includes the step of spontaneous peeling and unzipping of the bulk transition metal-dichalcogenide using a simple solution process, so that the manufacturing process is It has the advantage of being able to mass-produce a single-layer transition metal-dichalcogenide nanoribbon that is distorted in a simple, economical and efficient manner.

1 is a schematic diagram of a transition metal-dichalcogenide nanoribbon on a 1T or 1T' phase,
_{2A and 2B are SEM analysis results of Example 1 (intermediate product: MoS 2} nanosheets on 1T') after 5 minutes and 60 minutes of ultrasonic treatment, respectively, and FIG. 2C is a comparison This is the SEM analysis result of Example 1 (MoS _{2 nanosheet on 2H),}
3 is a SEM-EDS analysis result of Example 1 (MoS _{2 nanoribbons on 1T'), each partially unziped,}
Of Figure 4 (a) of Example 1 (1T 'on MoS ₂ nanoribbons) are TEM analysis of the, (b) of Fig. 4 and Example 1 (1T' average length and width of the on MoS ₂ nanoribbons) Is the result of analyzing
'As STEM analysis of the (MoS ₂ nanoribbons on, (a) in Example 1 (1T 5 Example 1 1T), and the result shows an enlarged grille on MoS ₂ nanoribbons), (b) Is the FFT (Fast Fourier Transform) transformed diffraction pattern, (c) is the result of showing the microstructure of _{the MoS 2 nanoribbon stabilized during the analysis of 1T',}
And Figure 6 is exemplary Raman spectrum analysis of example 1 (1T, MoS ₂ nanoribbons on), Example intermediate product (1T 1 'on the MoS ₂ nanosheets) and Comparative Example 1 (MoS ₂ nanosheet over 2H) results,
_{7 is an XPS analysis result of Example 1 (MoS 2} nanoribbon on 1T'), Comparative Example 1 (MoS ₂ nanosheet on 2H) and 1T': 2H composite nanosheet,
Figure 8 (a) is a result showing the pH change according to the second ultrasonic application time of the solution _{in which LiMoS 2} is dispersed in the manufacturing step of _{Example 1 (MoS 2 nanoribbon on 1T'), Figure 8 (b)} ) Is to theoretically clarify the process of unziping to _{the MoS 2 nanoribbons on 1T' as the S atoms of the MoS 2} nanosheets on the 1T' are contacted with O atoms and etched away in the manufacturing step of Example 1, It is the result of calculating the binding energy at the time of DFT through DFT calculation,
9 is a result of calculating the binding energy (eV) per oxygen atom according to the crystalline structure _{of MoS 2 and the bonding form of the oxygen (O) atom through DFT calculation,}
10A and 10B show that the sulfur (S) atoms have different bonds in the atomic structures of Comparative Example 1 (MoS ₂ nanoribbon on 2H) and Example 1 (MoS _{2 nanoribbon on 1T′), respectively.} This is the result of comparing the local electron density of state (LDOS) according to the location of different sulfur atoms calculated through the schematic diagram (inset) and DFT calculation.
11 is a result of analyzing the catalytic activity of a hydrogen evolution reaction (HER),
12A shows 1T' through DFT calculation based on a standard approach in order to theoretically investigate the catalytic activity of _{Example 1 (MoS 2 nanoribbon on 1T') for hydrogen evolution. Gibbs free energy (hereinafter, ΔG H*} ) for hydrogen adsorption and desorption was calculated at both the basal plane and the edge active site of the MoS ₂ nanoribbon of the phase and compared with the conventional Pt(111), FIG. 12 (B) of Example 1 is the result of calculating the exchange current density (jo) of _{Example 1 (MoS 2 nanoribbon on 1T') and pure metal through DFT calculation.}

Hereinafter, a transition metal-dichalcogenide nanoribbon of the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, unless there are other definitions in the technical terms and scientific terms used, they have the meanings commonly understood by those of ordinary skill in the technical field to which the present invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may be unnecessarily obscure will be omitted. In addition, the singular form used in the specification and the appended claims may be intended to include the plural form unless otherwise indicated in the context. In the present specification and the appended claims, units used without special mention are based on weight, and as an example, the unit of% or ratio means% by weight or a weight ratio.

In the present invention, the transition metal-dichalcogenide of the transition metal-dichalcogenide bulk, the transition metal-dichalcogenide sheet, or the transition metal-dichalcogenide nanoribbon is a transition metal and a knife having a two-dimensional layered structure. As a cogengan compound, the formula MX ₂ may be satisfied. In this case, in Formula MX ₂ , M may mean a divalent transition metal, and X may mean chalcogen. In Formula MX ₂ , M may be a metal selected from one or two or more of Cu, Ni, Co, Fe, Mn, Cu, Cr, V, Ti, Mo, Nb, Zr, W, Ta, Re and Hf, and X May be a chalcogen selected from one or two or more of S, Se and Te. In one embodiment _{, M of MX 2} may be one or two or more selected from Mo, W and Re, and X may be one or more selected from S, Se, and Te, but is not limited thereto. As a practical example, the transition metal-dichalcogenide may be a group 4 to 6 transition metal-dichalcogenide, and _{as a group 4 to 6 transition metal-dichalcogenide MoS 2 , TiS 2} , TaS ₂ , WS ₂ , MoSe ₂ , WSe ₂ , MoTe ₂ and the like, but are not limited thereto.

In the present invention, the transition metal-dichalcogenide bulk is an independent three-dimensional solid, and may mean a three-dimensional three-dimensional structure capable of maintaining a constant shape and supporting its own weight. For example, the transition metal-dichalcogenide bulk is at least 50 or more, specifically 100 or more, and more specifically 1000 or more transition metal-dichalcogenides based on a single layer of transition metal-dichalcogenide. It may be a three-dimensional three-dimensional including a layer, but is not limited thereto. As another example, the transition metal-dichalcogenide bulk has a size (length, width, thickness, diameter, etc.) on the basis of three axes orthogonal to each other, in each of the three axes, on the order of μm or more, specifically tens of micrometers. It may be the above three-dimensional three-dimensional, but is not limited thereto.

In the present invention, the transition metal-dichalkogenide sheet may mean a plate (or sheet)-type single-layer transition metal-dichalkogenide, that is, a single-layer transition metal-dichalkogenide sheet.

In the present invention, the transition metal-dichalkogenide nanoribbon may mean a strip-shaped single-layer transition metal-dichalkogenide. For example, transition metal-dichalcogenide nanoribbons have a length (ex.width) of several to tens of nm based on two axes orthogonal to each other in the plane direction of a single layer, and the length of the other axis is the length of one axis ( ex. width) may mean a single layer transition metal-dichalcogenide having a larger strip shape. As a practical example, the transition metal-dichalcogenide nanoribbon has an average length of 100 to 800 nm and an average width of 10 to 70 nm, specifically an average length of 200 to 400 nm and an average width of 30 to 60 nm, more specifically It may mean a strip-shaped single-layer transition metal-dichalcogenide having an average length of 250 to 350 nm and an average width of 35 to 50 nm. The transition metal-dichalcogenide nanoribbon may also be referred to as a 2-dimensional transition metal-dichalcogenide nanoribbon.

In the present invention, the transition metal-dichalcogenide mono-layer (single layer) is a three-atomic layer structure, that is, a laminated structure in which a transition metal layer is interposed between two chalcogen layers. As such, the chalcogen layer-transition metal layer-chalcogen layer may be bonded to each other through a Van der Waals interaction.

The method of manufacturing a nanoribbon according to the present invention is a method of manufacturing a transition metal-dichalcogenide nanoribbon having a two-dimensional structure, and a transition metal-dichalcogenide nanosheet of 1T' with reaction ions and And an unziping step of producing a single-layer transition metal-dichalcogenide nanoribbon on 1T' by contacting.

The method of manufacturing a nanoribbon according to the present invention can prepare a two-dimensional transition metal-dichalcogenide nanoribbon through a simple and relaxed process of contacting the reaction ions with the transition metal-dichalkogenide nanosheet. In detail, reaction ions are bonded to the transition metal-dichalcogenide nanosheet of 1T' to remove chalcogen, so that the nanosheet may be unzipping with the nanoribbon.

When unziping using reactive ions, the transition metal-dichalcogenide nanosheet in contact with the reactive ions is a 1T' phase transition metal-dichalcogenide nanosheet. 1, the 1T' phase has a structure in which chalcogen is regularly distorted in the 1T phase, and thus the 1T' phase is also referred to as a distorted 1T phase.

The transition metal-dichalcogenide nanosheet on 1T' prevents random reactive ion bonding and allows reactive ions to bind to the nanosheet in a longitudinal shape across the nanosheet, so that it is well-defined. Ribbon can be formed in a strip shape, and most of the input 1T' phase transition metal-dichalcogenide nanosheets can be converted into ribbons.

Specifically, when the transition metal-dichalcogenide nanosheet is in the 1T' phase, the nanosheet has a distorted structure as shown in the schematic diagram shown as 1T' in FIG. 1, and the chalcogen of the nanosheet has two different energy states. It can be divided into species chalcogens. When the transition metal-dichalcogenide nanosheet on 1T' comes into contact with the reactive ions, the reactive ions are selectively selected from the chalcogen of one energy state, which provides a more stable bond state among the two chalcogens having different energy states. By this selective bonding, chalcogen in a specific energy state is etched away, and nanoribbonization (ribbonization) can be performed.

In other words, in the transition metal-dichalcogenide nanosheet of 1T' phase, unlike other phases, reactive ions are not bonded to random positions, and reactive ions are selectively combined with chalcogens in a specific energy state to remove chalcogens by etching. By doing so, nano-ribbons can be made into a nanosheet.

In one embodiment, the unziping in which the nanosheets are nanoribbonized may be performed by contacting the 1T'-phase transition metal-dichalkogenide nanosheet with an unziping solution containing reactive ions. That is, the method of manufacturing a nanoribbon according to one embodiment is a single layer transition of 1T' by contacting the transition metal-dichalcogenide nanosheets with the reaction ions in the liquid (unziping liquid) under a medium in the form of a liquid (unziping liquid). It may include; an unziping step of preparing a metal-dichalcogenide nanoribbon.

In the case of using a liquid unziping liquid in the unziping step, by appropriately controlling the content of reacted ions in the unziping liquid, chalcogens other than energetically stable chalcogens (different from chalcogens that bind to oxygen) are Energy chalcogen) can be stably prevented from binding with reactive ions, and since the nanosheet is in a dispersed state, reactive ions can be uniformly supplied to the nanosheet.

In one embodiment, the content of the reaction ions contained in the unziping solution may be 5 to 15 mg/L, specifically 8 to 12 mg/L, and more specifically 8 to 10 mg/L at 20°C. The weight ratio of the unziping liquid and the transition metal-dichalcogenide mixed with each other in the ping step may be, for example, 1: 5 to 15, specifically 1: 8 to 12, but is not limited thereto.

The medium (solvent) of the unziping liquid may be a solvent in which the reaction ions are stably dissolved in a preset concentration range.

In addition, when the chalcogen of the nanosheet reacts with oxygen, nitrogen, or phosphorus derived from reactive ions in a liquid medium, the chalcogen can be rapidly removed in the form of gaseous chalcogen oxide or acid, and also, a liquid medium It is advantageous because it is possible to apply a physical impact through the device to promote nanoribbonization.

In one embodiment, when the unziping liquid is used, ultrasonic waves may be applied in the unziping step. That is, in the method of manufacturing a nanoribbon according to an embodiment, a single layer transition metal-dichalcogenide on 1T' by contacting a transition metal-dichalcogenide nanosheet and an unziping solution containing reactive ions, and applying ultrasonic waves. It may include; unziping step of manufacturing a nanoribbon.

As described above, ultrasonic waves may be applied to the unziping liquid mixed with the nanosheets, and the ultrasonic waves may promote etching removal of chalcogens bound to reactive ions, and chalcogens in a specific energy state are removed. It can cause physical impact to the nanosheets so that the nanosheets are cut faster along the defect line. In addition, as described later, when unziping (nanoribbonization) and peeling from bulk to nanosheets are performed in a single process (at the same time), peeling of single-layer transition metal-dichalcogenide nanosheets can be promoted. There is an advantage.

When unziping, the ultrasonic waves may be applied at an output of 100 to 1000 W, a temperature of 20 to 40° C., and for 10 minutes to 10 hours, but such reaction conditions are exemplary, and the present invention is not necessarily limited thereto. In addition, if necessary, cleaning using a hexane column or the like may be performed before or during ultrasonic application, but is not limited thereto.

As described above, the use of the unziping liquid has several advantageous advantages, but the present invention does not exclude contact with reactive ions other than the liquid phase. Contact with the reactive ions may be made through a gaseous, liquid, or solid (including gel state) medium, and the reactive ions may be gaseous, molten, dissolved, or solid.

In the unziping step, the reactive ions may be one or more ions selected from oxygen ions, nitrogen ions, or phosphorus ions, and the unziping liquid is dissolved oxygen obtained by purging a gas containing oxygen, nitrogen and phosphorus in water, It may be water containing dissolved inorganic nitrogen and dissolved inorganic phosphorus. In this case, the dissolved inorganic nitrogen may be nitrogen nitrate (NO ₃ ^-- N), nitrite nitrogen (NO ₂ ^-- N), ammonia nitrogen (NH ₄ ⁺ -N), and mixtures thereof, and the dissolved inorganic phosphorus may be phosphoric acid phosphorus ( PO ₄ ^3- -P).

In one embodiment, the manufacturing method of the nanoribbon includes ion insertion to prepare a transition metal-dichalcogenide interlayer compound in which alkali metal or alkaline earth metal ions are intercalated between the bulk transition metal-dichalcogenide layer before the unziping step. Step; may further include.

In order to manufacture a sheet of transition metal-dichalcogenide (single-layer sheet), which is a two-dimensional layered material, metal ions are inserted between the layers of the bulk of the transition metal-dichalcogenide to expand the layer and the layer, and then insert. By removing the formed metal ions, the bulk can be peeled off into a transition metal-dichalcogenide sheet.

Alkali metal ions may be one or more selected from lithium ions, sodium ions, potassium ions, rubidium ions and cesium ions, or alkaline earth metal ions may be one or more of beryllium ions, magnesium ions, calcium ions, strontium ions and barium ions. More than one can be selected. At this time, in terms of smooth and uniform ion insertion, the metal ions inserted between the bulk transition metal-dichalcogenide layers are preferably alkali metal ions, and lithium ions or sodium ions are more preferable.

The ion insertion step may include mixing a transition metal-dichalcogenide bulk and an intercalation solution, and the intercalation solution is a precursor of an alkali metal or alkaline earth metal ion (hereinafter, referred to as a metal precursor). Can include.

The metal precursors contained in the intercalation solution are alkali metal ions or alkaline earth metal ions halide (chloride, iodide, bromide, etc., fluoride), nitride, hydroxide, sulfide, oxide, oxyhydroxide, nitrate, acetate and sulfate. One or more than one may be selected from, but is not limited thereto.

The solvent contained in the intercalation solution may be a solvent in which the metal precursor is dissolved, but specifically, may be an organic solvent such as hexane, cyclohexane, and toluene, an aqueous solvent such as water, or a mixture thereof.

In the ion implantation step, the transition metal-dichalcogenide bulk has the structure of the nanosheet prepared by adjusting the intercalation conditions such as the molar concentration of the intercalation solution, the intercalation temperature, and the intercalation time to 1T'. Can be adjusted.

The molar ratio of the metal precursor and the transition metal-dichalcogenide may be in the range of 1: 0.01 to 0.20, specifically in the range of 1: 0.01 to 0.15, and more specifically in the range of 1: 0.01 to 0.09. The concentration may be, for example, in the range of about 0.01 to 1.5 M, specifically about 0.03 to 1.0 M, and more specifically about 0.15 to 0.50 M.

The intercalation temperature may be 30 to 120°C, specifically 30 to 110°C, and more specifically 30 to 100°C. The interaction time may be 3 to 60 hours, specifically 5 to 55 hours, and more specifically 10 to 50 hours, but is not limited thereto.

1T' phase nanosheets can be prepared in the above-described metal precursor concentration, mixing ratio, and temperature range, and 1T' phase nanosheets are controlled by adjusting the metal precursor concentration, mixing ratio, and temperature range within the above-described range in consideration of the material of the concrete nanosheet. The yield in which the sheet is manufactured can be improved.

As a practical example, when the bulk of the transition metal-dichalcogenide is MoS ₂ , in the aspect that the 1T'-phase nanosheet is manufactured with a high yield of 90% or more, during the ion insertion step, the metal precursor and the transition metal-dichalcogenide The molar ratio of 1: may be at the level of 0.03 to 0.05, the concentration of the metal precursor in the solution may be at the level of 0.35 to 0.50 M, and intercalation may be performed at a temperature of 80 to 100° C. for 45 to 60 hours.

After the ion insertion step is performed, a step of washing and/or drying the transition metal-dichalcogenide interlayer compound prepared by selectively inserting an alkali metal ion or an alkaline earth metal ion may be further performed.

Before the unziping step, after the transition metal-dichalcogenide interlayer compound is prepared by an ion insertion step, the intercalated alkali metal or alkaline earth metal ions are removed from the transition metal-dichalcogenide interlayer compound independently of the unziping step. And a peeling step of preparing a transition metal-dichalcogenide sheet may be performed.

This peeling step may be performed independently of the unziping step, or may be performed simultaneously in the unziping step.

As is known, the exfoliation of the transition metal-dichalkogenide interlayer compound can typically be performed in an aqueous (e.g., water) medium, and the transition metal-dichalkogenide interlayer compound is dispersed in an aqueous medium. I can. Alkali metal or alkaline earth metal ions inserted in the transition metal-dichalcogenide interlayer compound in the peeling step react with water to generate hydrogen gas, and the bulk (multilayer structure) transition metal- The layered structure in the dichalcogenide is peeled off, so that a single-layer transition metal-dichalcogenide sheet can be prepared. In order to promote the peeling in the peeling step, ultrasonic application or vigorous stirring may be performed if necessary.

When the peeling step is performed independently, the peeling step may be performed under conditions generally used for peeling the conventional transition metal-dichalcogenide interlayer compound into a single film. As an example, a peeling step may be performed by dispersing the transition metal-dichalcogenide interlayer compound in an aqueous medium and then applying an ultrasonic wave of 100 to 1000 W, but is not limited thereto.

However, the present invention may not be limited to that the peeling step and the unziping step are independently performed, and of course, the peeling step and the unziping step may be performed in a single process.

The process including the unziping step, the peeling step, and the ion implantation step may be performed under an inert atmosphere such as nitrogen, argon, neon, or the like.

The present invention includes a transition metal dichalcogenide nanoribbon prepared by the above-described manufacturing method.

The present invention includes a catalyst comprising a transition metal dichalcogenide nanoribbon prepared by the above-described manufacturing method.

The present invention provides a transition metal dichalcogenide nanoribbon having improved activity, specifically, a 1T'-phase monolayer transition metal dichalcogenide nanoribbon and a catalyst comprising the same.

In one embodiment, the nanoribbon may be a distorted 1T phase (1T' phase), and specifically 2a ₀ x2a ₀ (a ₀ = Mo-Mo distance, about 2.7 Å) It may have a 1T' crystal structure. _{At this time, as is known, J 1} , J ₂ and J ₃ peaks may appear in the Raman spectrum of the nanoribbon due to the 1T' crystal structure. Compared to other phases such as 1T (octahedral) or 2H (trigonal prismatic), the 1T' phase has a structure having a relatively high energy, and the 1T' nanoribbon may have improved reactivity compared to the nanoribbon of other phases.

One in the embodiments, nanoribbons can receive the Raman spectrum that the peak does not appear, or E ¹ _{2g 2g} E ¹ peak at an intensity of 0.1 or less, based on (1) the strength of the A _1g peak. In this case, the fact that the E ¹ _2g peak does not appear on the Raman spectrum of the nanoribbon may indicate a noise level level.

As is known, the Raman spectrum of a transition metal-dichalcogenide having a two-dimensional layered structure has two prominent peaks, an ^{E 1} _2g peak and an A _{1g peak.} E ¹ _2g is a peak formed by in-plane mode, and A _1g peak is a peak formed by out-of-plane mode. The in-plane mode is a mode by one-way vibration of a chalcogen element and a transition metal element, and the out-of-plane mode is a mode by out-of-plane vibration of a chalcogen element. The positions of the E ¹ _2g peak and the A _1g peak may vary depending on the specific material of the transition metal-dichalcogenide, and peaks may be formed at a known position (Raman shift) depending on the specific material. For example, in the case of molybdenum disulfide nanosheets, the E ¹ _2g peak may be located at 380 to 388cm ^-1 , and the A _1g peak may be located at 400 to 410cm ^-1.

In the Raman spectrum of nanoribbons, _{the relative intensity between the intensity of the A 1g} peak and the E ¹ _2g peak is a direct indicator of whether the in-plane vibration or out-of-plane vibration is relatively more active (intensified). . In the Raman spectrum of the nanoribbon, the E ¹ _2g peak does not appear, or the ^{E 1} _2g peak appears with an intensity of less than 0.1 based on the intensity of the _{A 1g peak (1).} -It may mean that of-plane vibration is remarkably activated (intensified), and it is an index indicating that the density of the edge site, which is a factor that strengthens out-of-plane vibration, is significantly increased.

In one embodiment, the nanoribbon has a remarkably high edge density, and thus can exhibit excellent activity. Specifically, the nanoribbon may have an edge density of 10 ¹⁵ pieces/cm ² or more, specifically 10 ¹⁵ to 10 ¹⁸ pieces/cm ² . In this case, the edge density may be an active point density calculated through a chemical reaction using a nanoribbon as a catalyst. The chemical reaction for calculating the active point density may be an electrochemical hydrogen generation reaction, and the active point density may be calculated by a turnover number (TON), which means the number of moles of the substrate converted from the number of moles of the catalyst. have. Although not necessarily limited to this interpretation, the Raman spectral properties representing markedly enhanced out-of-plane vibrations and/or edge densities corresponding to or beyond Pt are due to the large amount of kinks formed at the edges of the nanoribbons. Can be.

As described above, the nanoribbon has excellent charge transfer by the 1T' phase, which is a metal phase, and a high edge density that corresponds to or exceeds the density of the active site of platinum, thus exhibiting extremely excellent activity in various reactions involving charge. Can be indicated.

In one embodiment, the nanoribbons have an average width of 20 to 50 nm, specifically 30 to 50 nm, and an average length of 100 to 800 nm, specifically 200 to 600 nm, and more specifically 300 to 500 nm. have. In one embodiment, the nanoribbons are 20 to 50 nm, specifically 30 to 50 nm, and have a well-defined band shape of 100 to 800 nm with an average length, and may exhibit the above-described Raman spectral characteristics.

The present invention relates to a spin-orbital coupling characteristic of a single-layer transition metal-dichalcogenide having a conventional two-dimensional layered structure, such as an electronic device, a photoelectric device, an optical device, a memory device, a magnetic device, etc. including the catalyst including the nanoribbons described above. However, it may include a variety of devices using electrical properties, quantum-spinhole effect, and reactive activity.

The present invention includes a catalyst support comprising the nanoribbons described above.

As described above, the nanoribbon according to the present invention has very high activity and can itself be used as a catalyst, but if necessary, an additional heterogeneous catalyst material is also supported as a catalyst support supported, formed, or bonded to the above-described nanoribbon. Can be utilized.

The catalyst including the above-described nanoribbon can be used in various reactions known to use a transition metal-dichalcogenide having a conventional two-dimensional layered structure as a catalyst. As a specific example, the catalyst including the above-described nanoribbons is a catalyst for hydrogen evolution reaction (HER), a catalyst for oxidation reaction, a catalyst for photolysis, a catalyst for hydrogenation (hydrocracking) reaction, or an oxidative dehydrogenation reaction. It may be a catalyst, but is not limited thereto.

In addition, if necessary, by using the above-described nanoribbon as a support, active metals such as Au, Pt, Ag, Pd, etc. may be loaded (bonded, formed, supported) on the nanoribbon, but the present invention is a sphere loaded on the nanoribbon. It goes without saying that it cannot be limited by the active substance.

The present invention includes an electrode comprising a catalyst containing the nanoribbons described above. The electrode may include a current collector and a catalyst containing nanoribbons positioned on one or both sides of the current collector. At this time, of course, the electrode may further include a polymeric binder commonly used to fix the catalyst to the current collector, and although the nanoribbon contained in the catalyst is 1T' of metallic (conductor), It may not contain a separate conductive agent, but it may further contain a conductive agent if necessary, and the electrode should not be interpreted as excluding a conductive agent used in a conventional catalyst electrode.

The above-described nanoribbon is very excellent as a catalyst, especially a catalyst for hydrogen generation reaction. Accordingly, the present invention includes a catalyst for hydrogen generation reaction including the above-described nanoribbons. In the hydrogen generation reaction, due to the excellent activity of the above-described nanoribbon, the catalyst may have a higher turnover frequency (TOF) than Pt(III), which shows the best catalytic activity in the same reaction, and substantially 1.50s ^-1 or more. It may have a TOF, a TOF of more substantially 2.0s ^-1 , and a TOF of more substantially 3.0s ^-1 . In this case, TOF means the number of TONs per unit time, and TON can mean the number of moles of the substrate converted from the number of moles of the catalyst, of course.

In addition, due to the excellent activity of the above-described nanoribbons, the catalyst may have a current density of ^{10 mA/cm 2} or more at a low potential of 30 to 80 mV (vs. RHE, RHE = reversible hydrogen electrode). In addition, due to the excellent activity of the nanoribbons described above, it may have a Tafel slope of 40.0 mV/dec or less, specifically 37.0 mV/dec or less.

Further, by the good activity of the above-described nanoribbons, the catalyst support (including the current collector), the 1 to 100μg / cm ^2, particularly from 5 to 50μg / cm ^2, more specifically, bearing a very small amount from 5 to 30μg / cm ² level It is stable and can exhibit excellent catalytic performance in the state.

The present invention is an electrode for hydrogen generation reaction (hereinafter, HER electrode) comprising a catalyst containing the above-described nanoribbons; A hydrogen generating device comprising the same; And a hydrogen generation method using the same.

The hydrogen generating device according to the present invention includes a HER electrode provided with the above-described nanoribbon as a catalyst; Counter electrode; And an electrolyte; may include. The electrolyte may be an aqueous electrolyte, and specifically, may be an acidified aqueous electrolyte. The acidified aqueous electrolyte may have a pH of 2 or less, a pH of 0 to 1 in a specific example, and a pH of 0.1 to 0.5 in another specific example, and the acidification may be made by inorganic acids such as sulfuric acid or hydrochloric acid, but is limited thereto. no.

The counter electrode may be any electrode known to be used as a counter electrode of the HER electrode when electrochemical hydrogen is generated. For example, the counter electrode may be an electrode provided with an oxide of a transition metal (Mn, Fe, Co, Ni, Cu, etc.) or a noble metal such as hydroxide, Pt, or a noble metal oxide such as iridium oxide or ruthenium oxide as an active material. However, it is not necessarily limited thereto, and a conventional electrolyte and a counter electrode known to be used to generate hydrogen electrochemically are sufficient. In addition, if necessary, the hydrogen generating device may further include a separator (membrane) positioned between the HER electrode and the counter electrode, and the space of each electrode may be partitioned by the separator. In this case, the separator may be a hydrogen ion conductive separator, but is not limited thereto.

The present invention includes a hydrogen generating method using the above-described hydrogen generating device.

The present invention includes a method for generating hydrogen using an electrode for hydrogen generation reaction (HER electrode) including a catalyst containing the nanoribbons described above. In detail, hydrogen may be generated by applying a voltage between the HER electrode and the counter electrode in a state in which the HER electrode and the counter electrode disposed between the separator and the counter electrode are in contact with the electrolyte. At this time, the counter electrode and the electrolyte are the same or similar to those described above in the hydrogen generating device.

Further, in the present invention, the catalyst containing the nanoribbons described above can be further applied to applications of oxygen generation reaction (OER), supercapacitors, and batteries.

(Example 1) Preparation _{of MoS 2 nanoribbons on 1T'}

All of the following procedures were performed in a glove box under an _{N 2 atmosphere.}

1) 2H-phase bulk MoS ₂ powder (purity 99.8%) was left at 60° C. for 48 hours in a vacuum atmosphere to remove (degas) gas in the _{bulk MoS 2 powder.}

2) Degassed 2H bulk MoS ₂ powder 100 mg was added to 10 mL of a 0.48 M n-butyllithium/hexane solution (hereinafter, n-BuLi, stock concentration = 16 M), and stirred at 90° C. for 48 hours to A suspension was formed. _{At this time, the fixed volume of degassed bulk MoS 2} powder added to n-BuLi is 10 mg/mL.

3) The prepared first suspension was filtered through a Millipore membrane and washed several times with hexane to separate _{the MoS 2 bulk containing lithium ions from the remaining n-BuLi.}

4) The lithium ion-inserted MoS ₂ bulk was dispersed in oxygenated water, and then separated by ultrasonic treatment at 500 W for about 30 minutes at room temperature. At this time, oxygenated water is water having saturated oxygen obtained by injecting oxygen gas into water contained in a sealed container for 1 hour.

5) Slowly drop the solution of step 4) into a column (3000 mL) filled with hexane at a rate of 0.1 mL/min ^{to precipitate Li +} and carbon, and centrifuge the solution recovered from the hexane column several times in high-purity deionized water. After separating and removing impurities and non-exfoliated MoS ₂ , an aliquot was recovered to obtain exfoliated 1T'-phase MoS ₂ nanosheets.

6) After preparing a second suspension by placing the recovered MoS ₂ nanosheets on 1T' in a container filled with 200 mL of oxygen water, the second suspension was ultrasonicated at room temperature at 500 W for 2 hours to unzip.

7) 6) sufficiently aging (aged), the solution of step and then centrifuged for 2 hours at 20000 rpm to remove the supernatant containing the Li and impurities, 6) from the solution of step a MoS ₂ nanoribbons on 1T ' Recovered.

9) Recovered 1T'-phase MoS ₂ nanoribbons were redispersed in ethanol or water, centrifuged several times from 3000 rpm to 8000 rpm _{to remove non-peelable and partially unziped MoS 2} at 40° C. under Ar atmosphere. Drying in vacuum to obtain _{a MoS 2 nanoribbon.}

(Examples 2 to 4) Preparation of MoSe ₂ /MoTe ₂ /WSe ₂ nanoribbons on 1T'

_{MoSe 2} /MoTe ₂ /WSe ₂ nano on 1T' using the same method as in Example 1, if only the concrete materials and specific experimental conditions of the steps 1) and 2) of Example 1 were reconstituted to satisfy Table 1 below. The manufacture of the ribbon was prepared.

(Comparative Example 1) Preparation of _{2H-phase MoS 2 nanosheet}

In step 4) of Example 1, _{instead of dispersing the lithium ion-inserted MoS 2} bulk in deionized water and sonicating at 500 W for 2 hours, the lithium ions intercalated MoS ₂ bulk was added to an ethanol-water mixture. (Volume ratio = 1:1) and except for sonication at 500W for 1 hour, steps 1) to 5) of Example 1 were sequentially performed to obtain 2H-phase MoS ₂ nanosheets.

(Material property analysis)

In order to analyze the microstructure, transmission electron microscopy (TEM) analysis, scanning tunneling microscopy (STM), and scanning tunneling spectroscopy (STS) analysis were performed. TEM analysis was performed using a spherical aberration-corrected transmission electron microscope (FEI spherical aberration-corrected 80-300 Titan environmental (scanning), FEI Titan E-(S)TEM) operated at 80 kV. It was carried out at 77 K in an ultrahigh vacuum.

In order to analyze the crystal structure, photoluminescence/Raman (PL/Raman) analysis and X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, hereinafter XPS) were performed. PL/Raman analysis was performed using a spectrophotometer (WITEC alpha500 Confocal Raman system, 532nm, ~1mW) in an atmospheric environment. Raman scattering was collected by an objective lens (Olympus × 100, 0.9 NA) and dispersed in ^{1,800 and 600 line mm -1 grids for Raman and PL measurements, respectively.} XPS analysis was performed using a photoelectron spectroscopy (K-Alpha, Thermo VG scientific). In addition, the pH analysis was performed by measuring the pH using a pH meter.

(Thermodynamic analysis)

In thermodynamic analysis, density functional theory (DFT) calculation was used to calculate the oxygen atom bonding energy according to the oxygen atom bonding type of the structure. In detail, the DFT calculation was performed assuming the coupling length shown in Table 2. In this case, TM-D in Table 2 is the bond length between the transition metal atom and the chalcogen atom, and D-H is the bond length between the chalcogen atom and the hydrogen atom adsorbed on the chalcogen atom.

(Analysis of electrochemical properties)

In order to analyze the electrochemical properties, a three-electrode cell was constructed and linear sweep voltammetry (LSV) was performed, and compared with Pt/C. Embodiment of the 15 μg Example 1 of 1T 'on MoS ₂ nanoribbons (hereinafter, uz-1T'), MoS on the 2H of "MoS ₂ nanosheets (hereinafter, ef-1T on ') Comparative Example 1, 1T ₂ nanosheets ( Hereinafter, ef-2H/O ₂ ) _, hydrated LixMoS ₂ (hereinafter, uef-1T'/O ₂ ) _, and Pt/C (20% Pt on Vulcan XC72, Premetek, P10A200) were each 0.1 mL of The catalyst ink was prepared by dispersing in ethanol. Saturated calomel electrode was used as the reference electrode, Pt was used as the counter electrode, and the working electrode was 15 μg/cm per unit area on a glass carbon electrode, and 15 μg/cm per unit area in ^{two stages.} After applying catalyst ink so that cm ² of catalyst is loaded and drying at 60° C., 15 μg/cm ² of 5% Nafion was deposited and used _{to protect the surface of the working electrode, and 0.5MH 2} SO ₄ electrolyte (pH 2, aqueous solution) at a scan rate of 5 mV/s. At this time, the analyzed potential was expressed as a potential for a reversible hydrogen electrode (RHE).

2A and 2B are SEM analysis results of _{Example 1 (intermediate product: MoS 2} nanosheets on 1T') after 5 minutes and 60 minutes of ultrasonic treatment, respectively. As can be seen from the results, it can be seen that _{the edges of the MoS 2} nanosheets on 1T' are unziped and begin to be released after 5 minutes of ultrasonic treatment.After 60 minutes of ultrasonic treatment, the MoS ₂ nanosheets on 1T' It can be seen that the 1T' phase MoS ₂ nanoribbons in the form of a well-defined band were completely unziped and released. Figure 2 (c) is a SEM analysis result of Comparative Example 1 (2H-phase MoS _{2 nanosheets).} As can be seen from the results, it can be seen that the 2H-phase MoS ₂ nanosheets generate irregular pores and become porous only, and it can be confirmed that ribbon formation is not achieved by unziping.

3 is a SEM-EDS analysis result of Example 1 (MoS _{2 nanoribbons on 1T') partially unziped, respectively.} As shown, it can be seen that Example 1 (MoS ₂ nanoribbon on 1T') was prepared in a form in which molybdenum (Mo), oxygen (O), and sulfur (S) atoms were uniformly distributed throughout.

Of Figure 4 (a) of Example 1 (1T 'on MoS ₂ nanoribbons) are TEM analysis of the, (b) of Fig. 4 and Example 1 (1T' average length and width of the on MoS ₂ nanoribbons) Is the result of analysis. As can be seen from the results, it can be seen that _{the average length of Example 1 (MoS 2} nanoribbon on 1T') is 300 nm and the width is 40 nm. Although not shown in the drawings, Example 2 (MoSe ₂ nanoribbon on 1T'), Example 3 (MoTe ₂ nanoribbon on 1T') and Example 4 (uz-1T' WSe ₂ nanoribbon on 1T') were also carried out. It was confirmed that a nanoribbon of a shape similar to Example 1 (MoS _{2 nanoribbon on 1T') was prepared.}

'As STEM analysis of the (MoS ₂ nanoribbons on, (a) in Example 1 (1T 5 Example 1 1T), and the result shows an enlarged grille on MoS ₂ nanoribbons), (b) Is the FFT (Fast Fourier Transform) transformed diffraction pattern, and (c) is the result showing the microstructure of _{the MoS 2 nanoribbon stabilized during the analysis.} As can be seen from the results, _{the crystal structure of Example 1 (MoS 2} nanoribbon on 1T') is similar to a conventional transition metal-dichalcogenide (MX ₂ ) chemically exfoliated, and a distorted 1T phase (1T' ), which is the crystal lattice structure of 2a ₀ x2a ₀ super lattice structure.

Figure 6 Example 1 is the result of the Raman spectrum analysis (1T 'on MoS ₂ nanoribbons, 1T' MoS ₂ nanosheets on) and Comparative Example 1 (MoS ₂ on the nanosheet 2H). In the figure, J1, J2 and J3 peaks are Raman peaks on 1T', and E ¹ _2g and A _1g are peaks related to the in-plane vibration mode and the out-of-plane vibration mode, respectively. As shown, the Raman spectrum of Example 1 (MoS ₂ ^{nanoribbon on 1T') is 156 cm -1} (J1), 228 cm ^-1 (J2), 330 cm ^-1 (J3) and 401 cm ^-1 ( A strong energy band is observed in _{1g ), and Raman spectra of MoS 2} nanosheets on 1T' and Comparative Example 1 (MoS ₂ nanosheets on 2H) are 383 cm ^-1 (E ¹ _2g ) and 404 cm ^-1 (A It can be seen that a strong energy band is observed at _{1g ).} In particular, Example 1 (1T 'MoS ₂ nanoribbons on) in the Raman spectrum of the MoS ₂ - may determine that the peak representing the plane vibration mode (E ¹ _2g) does not exist, which 1T' MoS ₂ nm on the This is because the out-of-plane vibration mode was preferentially activated because the density of the edge site (active point density) was greatly increased as the sheet was unziped _{and transformed into a MoS 2 nanoribbon on 1T'.}

_{7 is an XPS analysis result of Example 1 (MoS 2} nanoribbons on 1T'), Comparative Example 1 (MoS ₂ nanosheets on 2H) and 1T': 2H composite nanosheets. At this time, the nanosheets of the 1T':2H composite phase were prepared _{by intercalating lithium ions in the MoS 2} bulk using a low concentration n-butyllithium/oxygen solution, and then forming a nanosheet similar to the Example. As shown, the Mo 3d orbital of Example 1 (MoS ₂ nanoribbon on 1T') unziped through ultrasonic treatment was prepared by liquid separation on hydrogen peroxide without performing ultrasonic treatment, Comparative Example 1 (MoS _{2 on 2H)} It can be seen that the binding energy is lower and the strength is higher than that of the nanosheet). This is, in Example 1 (MoS _{2 nanoribbons on 1T'), SO 2} formed by contacting oxygen (O) atoms and sulfur (S) atoms in the manufacturing step is longitudinal along oxygenated line faults. By etching and removing, the _{total content of oxygen and sulfur in Example 1 (MoS 2} nanoribbons on 1T') was lowered, thereby increasing the strength of molybdenum and lowering the binding energy of oxygen atoms.

Figure 8 (a) is a result showing the pH change according to the ultrasonic application time during peeling and unziping of lithium-inserted MoS ₂ (LixMoS _{2 ) in the manufacturing step of Example 1 (MoS 2 nanoribbon on 1T')} to be. As can be seen from the results, it can be seen that the pH rapidly decreases from the initial 14.2 pH (alkali) to 3.4 pH (acidic), and the acidity gradually decreases as the ultrasonic application time increases. This initial high alkaline pH is _{caused by LiOH generated by the hydration of lithium-intercalated MoS 2} , and the rapid pH change (alkali→acidity) during the initial 5 minutes is caused by the combination of oxygen and sulfur during the application of ultrasonic waves. This is due to the dissolution of the produced SO _{2 (SO 2} + H ₂ O = H ₂ SO _{3 ).} Through this, it can be seen that the oxygen is combined with the chalcogen of the transition metal dichalcogenide to remove the chalcogen by etching, but it can be seen that ribbon formation is achieved by selectively bonding to specific positions across the transition metal dichalcogenide sheet.

As described above, in order to theoretically confirm the process of unziping into _{the MoS 2} nanoribbons on 1T' as the S atoms of _{the MoS 2} nanosheets on 1T' are contacted with O atoms and etched away in the manufacturing step of Example 1, S valence The binding energy at the time of etching was calculated through DFT calculation, which is shown in (b) of FIG. 8. , 1T combination of MoS ₂ nano-sheet on the "Contact with O atoms are S atoms in the basal plane of MoS ₂ nanosheets on the public (vacancy) of the S atoms is created and, 1T depending on converted into SO ₂ species' as illustrated It can be seen that the energy decreases to a negative value.

In addition, the _{binding energy (eV) per oxygen atom according to the crystalline structure of MoS 2} and the bond form of the oxygen (O) atom was calculated through DFT calculation and shown in FIG. 9, and FIGS. 9A and 9B MoS ₂ is a nanosheet and MoS ₂ on the nanosheet on each 2H 1T '. In the drawing, eV is a binding energy per oxygen atom according to a different oxygen atom to form (irregular (random), or straight (linear) in each of the nano-sheet, which was calculated by the DFT calculation, coupled to the MoS ₂ surface in DFT calculation As can be seen from the results, _{the oxygen atom binding energy of the MoS 2} nanosheet on 1T' is -0.75 eV or -0.95 eV, respectively, in the case of irregular or linear form, and the oxygen atom is in a linear form. It can be seen that the binding energy when bonded to is lower, and it is spontaneously unzipping in a straight line during etching, whereas the binding energy of oxygen atoms of _{the MoS 2 nanosheets on 2H is irregular or linear, respectively-} As 0.67 eV or -0.63 eV, the binding energy when oxygen atoms are irregularly bonded is lower, and it can be seen that chalcogen etching occurs by oxygen at irregular locations, resulting in porosity rather than ribbon formation.

In more detail, the binding energy (eV) per oxygen atom according to the crystal phase structure of the transition metal-dichalcogen compound having different chalcogen elements and the bond form of the oxygen (O) atom was calculated through DFT calculation and is shown in Table 3. . As shown, it can be seen that, regardless of the type of chalcogen (S, Se, and Te), the binding energy is lower in the case of a 1T' phase than a 2H phase and a linear bond than an irregular bond.

10A and 10B show that the sulfur (S) atoms have different bonds in the atomic structures of Comparative Example 1 (MoS ₂ nanoribbon on 2H) and Example 1 (MoS _{2 nanoribbon on 1T′), respectively.} This is the result of comparing the local electron density of state (LDOS) according to the location of different sulfur atoms calculated through the schematic diagram (inset) and DFT calculation. As shown, in the case of Example 1 (1T' phase), it can be seen that S1 has a higher density of states than S2, because the Fermi level of S1 is higher than S2. Therefore, in the case of the 1T' phase, as S1 has a higher Fermi level than S2, it can be predicted that it has a higher density of states and a stronger hybridization tendency between the S atom and the p orbital of oxygen. In addition, in the case of Comparative Example 1 (2H phase), it can be confirmed that irregular oxygen bonding occurs because there is almost no difference in the density of electrons between S1 and S2.

11 is a result of analyzing the catalytic activity of a hydrogen evolution reaction (HER). 11A and 11B are graphs of Linear Sweep Voltammetry (LSV) graphs and Tafel slopes derived from LSVs, respectively. As shown, uz-1T' has a current density (j) of ^{10 mA/cm 2} at a very low potential (~70 mV, compared to RHE), 36.2 despite a very small loading amount (10-15 μg/cm ^{2 ).} It has a tafel slope of mV/dec and ^{an alternating current density of 8.8x10-6 A/cm 2} , showing the best HER catalytic activity, and also has HER catalytic properties similar to the conventional Pt/C catalyst, and Pt/C of noble metal It is expected to be able to replace. On the other hand, it can be seen that ef-1T' exhibits better HER performance than uef-1T'/O _{2 .Through this, a thinner layer of MoS 2} has excellent catalytic activity for hydrogen evolution regardless of the crystal phase of the metal. Can be seen. In addition, high porosity and exfoliated ef-2H/O ₂ exhibited the lowest HER catalytic activity among nanosheets having a similar thickness due to exfoliation, which indicates that high-density edge sites (active points) were generated around pores in the crystal plane. However, it is interpreted that charge transfer is prevented by the low electrical conductivity resulting from the 2H phase and thus the HER catalytic activity is lowered.

(C) of FIG. 11 is a result of electrochemical impedance spectroscopy (EIS). As shown, it can be seen that uz-1T' has a higher resistance compared to ef-1T', which is due to the destruction of the crystal plane during unziping and oxygen bonding (the process of bonding O atoms to S atoms). This is because the electrical conduction characteristics have deteriorated. Figure 11 (d) is a result of comparing the HER catalyst properties before and after 1000 cycles of _{Example 1 (MoS 2 nanoribbon on 1T') and Example 1 (MoS 2} nano on 1T' operated for 10 hours at -0.3 V) Ribbon) is the result of analyzing the current density (inset). As can be seen from the results, in Example 1, the HER catalyst characteristics were almost unchanged before and after 1000 cycles, and even during operation at -0.3 V for 10 hours, except for the initial small reduction amount, it was stably maintained at a constant current density value. I can see that it is. Although not shown in the drawings, Example 2 (MoSe ₂ nanoribbons on 1T'), Example 3 (MoTe ₂ nanoribbons on 1T') and Example 4 (WSe ₂ nanoribbons on 1T') are also Example 1 (1T _{MoS 2} nanoribbons on': uz-1T' MoS ₂ in the figure showed similar HER catalytic activity.

12(a) is 1T' through DFT calculation based on a standard approach in order to theoretically investigate the catalytic activity for hydrogen evolution of _{Example 1 (MoS 2 nanoribbon on 1T'). Gibbs free energy (hereinafter, ΔG H*} ) for hydrogen adsorption and desorption was calculated at both the basal plane and the edge active site of the MoS ₂ nanoribbon of the phase and compared with the conventional Pt(111). At this time, ΔG _H* ) was calculated from the equilibrium potential, and in the figure, ^* is an adsorption site (active point), and H ^* is a hydrogen atom adsorbed on the surface. As shown, it can be seen that the passivated edges of Example 1 (MoS ₂ nanoribbon on 1T') have a higher active point compared to the base surface. In particular, it can be confirmed that △G _H* of Example 1 (MoS ₂ nanoribbon on 1T') is close to 0 compared to other Mx ₂ (MoSe ₂ , MoTe ₂ and WSe ₂ ) or Pt (111), through which It can be predicted that Example 1 has _{remarkably superior HER activity compared to other Mx 2} or Pt (111).

In addition, the exchange current density (jo) of Example 1 (MoS ₂ nanoribbon on 1T') and pure metal was calculated through DFT calculation, and this is shown in FIG. 12B. At this time, the exchange current density was calculated as a function of the Gibbs free energy of the adsorbed atomic hydrogen (DG _H* ), and for comparison, it was normalized to the active point density of Pt (1.5x10 ¹⁵ sites/cm ^{2 ).} As shown, it can be seen that a catalyst with adsorption free energy similar to that of proton and gaseous hydrogen (typical noble metal catalysts such as Pt and Pd) has the highest HER activity, and a kind of volcano plot is drawn. I can. This is a good example of the well-known Sabatier principle in the concept of catalytic reaction. On the other hand, _{it can be seen that Example 1 (MoS 2} nanoribbons on 1T') has excellent HER catalyst properties comparable to these Pt and Pd catalyst groups.

In order to further investigate the catalytic properties of the hydrogen generation reaction of Example 1 (MoS ₂ nanoribbon on 1T'), the hydrogen conversion efficiency (turnover frequency, hereinafter TOF) was calculated, and compared with Pt, a conventional noble metal catalyst. It is shown in Table 4. As shown, it can be seen that Example 1 has remarkably excellent HER catalytic activity with Pt. Through this, it can be seen that it can replace the HER catalyst of noble metals. Here, the physical properties of Pt, a conventional noble metal catalyst, were referred to Science 317, 100 (2007).

As described above, in the present invention, specific matters and limited embodiments and drawings have been described, but this is provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is Those of ordinary skill in the relevant field can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be defined, and all things that are equivalent or equivalent to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. .

Claims (15)

A catalyst comprising a distorted 1T (1T') monolayer transition metal dichalcogenide nanoribbon. The method of claim 1,
The nanoribbon is a catalyst having no ^{E 1} _2g peak in the Raman spectrum, or having an intensity of 0.1 or less based on the intensity of the _{A 1g peak (1).} The method of claim 1,
The catalyst has an edge density of 10 ¹⁵ pieces/cm ^{2 or more of the nanoribbons.} The method of claim 1,
The nanoribbons have an average length of 100 to 800 nm, and an average width of 10 to 70 nm of a band-shaped catalyst. The method of claim 1,
The transition metal of the transition metal-dichalcogenide is a group VIB transition metal catalyst. The method of claim 1,
The transition metal-dichalkogenide chalcogen is one or two or more selected from S, Se and Te catalyst. A catalyst for hydrogen evolution (HER; Hydrogen Evolution Reaction) comprising the catalyst according to any one of claims 1 to 6. A catalyst support comprising the catalyst according to any one of claims 1 to 6. A method for generating electrochemical hydrogen using the catalyst according to any one of claims 1 to 6. Distorted 1T (1T') monolayer transition metal dichalcogenide nanoribbons. An unziping step of preparing a single-layer transition metal-dichalcogenide nanoribbon by contacting the 1T'-phase transition metal-dichalkogenide nanosheet with reactive ions. The method of claim 11,
The contact is a method of manufacturing a nanoribbon performed by mixing with an unziping liquid containing reactive ions. The method of claim 12,
The reaction ions are oxygen ions, nitrogen ions, phosphorus ions, and the like. The method of claim 12,
A method of manufacturing a nanoribbon in which ultrasonic waves are applied to the unziping liquid mixed with the nanosheets. The method of claim 11,
Before the contact, an ion insertion step of preparing a transition metal-dichalcogenide interlayer compound in which an alkali metal or alkaline earth metal ions are intercalated between the bulk transition metal-dichalcogenide layers.

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