WO2022250299A1

WO2022250299A1 - Single metal atom catalyst of p-d orbital hybrid type for oxygen evolution reaction, and method for preparing same

Info

Publication number: WO2022250299A1
Application number: PCT/KR2022/005761
Authority: WO
Inventors: 김용태; 김영우; 정상문
Original assignee: 포항공과대학교 산학협력단
Priority date: 2021-05-28
Filing date: 2022-04-22
Publication date: 2022-12-01
Also published as: KR20220162191A; KR102604417B1

Abstract

The present invention relates to a single metal atom catalyst of a p-d orbital hybrid type for an oxygen evolution reaction and a method for preparing same. More specifically, the present invention relates to a single metal atom catalyst of a p-d orbital hybrid type for an oxygen evolution reaction which increases oxygen evolution reaction efficiency compared to a loading amount of noble metals through hybridization between a p-orbital of a catalyst carrier (p-block element) and a d-orbital of a noble metal-based metal (d-block element), and can dramatically reduce the amount of noble metals to be used, and to a method for preparing same. The present invention has the advantages of overcoming a scaling limit between the adsorption of an intermediate and the desorption of a product through the hybridized single atom catalyst, and of being able to solve a secondary reaction problem that occurs unnecessarily in terms of catalytic activity.

Description

P-D orbital hybrid type single metal atom catalyst for oxygen generation reaction and manufacturing method thereof

The present invention relates to a p-d orbital hybrid single metal atom catalyst for oxygen generation reaction and a method for preparing the same. More specifically, the present invention increases the efficiency of the oxygen generation reaction and drastically reduces the amount of noble metal catalyst used through hybridization between the p-orbital of the catalyst carrier (p-block element) and the d-orbital of the noble metal-based metal (d-block element) It relates to a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction that can be reduced to , and a method for manufacturing the same.

Development of a high-performance catalyst is the surest way to improve the energy conversion efficiency of P2G technology. Currently, the most active energy conversion catalyst research is in the field of metal nanoparticle catalysts (Nanoparticle Catalyst, NPC).

This relates to the composition and microelectronic structure control of catalyst elements, and a process of increasing the active surface area by reducing the particle size of NPC with a particle size of 100 nm or less and thereby improving the activity compared to the unit active surface area of the catalyst is used.

On the other hand, the reaction mechanism of the catalyst includes a process in which catalyst particles adsorb reactants and intermediates and desorb reaction products, and in order to increase the activity of the catalyst, the adsorption strength of the intermediates must be strong and the products desorbed smoothly.

However, in actual reactions, there is an intrinsic catalytic activity limit of a scaling relation in which intermediates such as reactants and products have the same increase and decrease tendencies.

In the conventional multi-atomic catalyst, several catalytic atoms interact with the reaction target material to cause an unintended secondary reaction, which causes side effects such as reduction in the efficiency of the catalytic reaction and damage to the catalyst due to unnecessary products. .

In order to solve this problem, single atom catalysts have been proposed as an alternative, but they also have many limitations in maximizing the surface area of expensive metals to increase catalytic efficiency and at the same time to improve activity and selectivity in catalytic reactions.

Therefore, there is an urgent need for technology development that meets the needs for low-cost, high-efficiency single atom catalysts that are rapidly increasing in various industrial fields, and KR10-1736065 and KR10-1505285 are examples of such, but the disclosure that solves the above is still Can't find it.

Accordingly, the present inventors, while making diligent efforts to improve the above problems, oxygen generation reaction through hybridization between the p-orbital of the catalyst carrier (p-block element) and the d-orbital of the noble metal (d-block element) The present invention, which can increase efficiency and drastically reduce the amount of noble metal catalyst used, has been completed.

An object of the present invention is to increase the oxygen generation reaction efficiency and drastically reduce the amount of precious metal catalysts used through hybridization between the p-orbital of a catalyst carrier (p-block element) and the d-orbital of a noble metal-based metal (d-block element) It is to provide a single metal atom catalyst in the form of a p-d orbital hybrid for oxygen generation reaction that can be reduced.

Another object of the present invention is to overcome the scaling limit between adsorption of intermediates and desorption of products through a hybridized single atom catalyst and to solve the problem of secondary reactions unnecessarily occurring in terms of catalytic activity. It is to provide a method for preparing an atomic catalyst.

The above and other objects of the present invention can all be achieved by the present invention described below.

One aspect of the present invention is a p-d orbital for oxygen generation reaction comprising a catalyst support formed by doping a metal material with a p-block element and a single metal atom layer formed on the surface of the catalyst support. It relates to a hybrid type single metal atom catalyst.

In a specific embodiment, the metal material forming the catalyst carrier is titanium, and the p-block element may be any one of carbon, nitrogen, and oxygen.

In embodiments, the material forming the single metal atomic layer may be a noble metal-based metal.

In embodiments, the noble metal-based metal may be any one of gold, silver, platinum, palladium, rhodium, ruthenium, and iridium.

In embodiments, the thickness of the single metal atomic layer may be 0.1 nm to 2 nm.

Another aspect of the present invention is to form a catalyst support by doping a p-block element on a metal material, and depositing a noble metal-based metal on the catalyst support to have a thickness of 0.1 nm to 2 nm. It relates to a method for producing a single metal atom catalyst in the form of a p-d orbital hybrid for oxygen generation reaction, comprising forming a single metal atom layer.

In a specific embodiment, in the step of forming the catalyst carrier, when the metal material is titanium and the p-block element is carbon, the titanium metal is heated under a methane atmosphere through a heater to form a surface Titanium carbide (TiC) can be produced.

In a specific embodiment, in the step of forming the single metal atom layer, when the metal material is titanium and the p-block element is carbon, the catalyst carrier made of titanium doped with titanium carbide on its surface. A single metal atom layer may be formed by depositing iridium thereon.

In a specific example, the thickness of the single metal atom layer made of iridium deposited in the step of forming the single metal atom layer may be 0.1 nm to 2 nm.

The p-d orbital hybridized single-metal atom catalyst for oxygen generation reaction according to the present invention is a noble metal through hybridization between the p-orbital of a catalyst carrier (p-block element) and the d-orbital of a noble metal-based metal (d-block element). It has the advantage of increasing the oxygen generation reaction efficiency compared to the supported amount and drastically reducing the amount of noble metal catalyst used.

The method for preparing a single metal atom catalyst in the form of p-d orbital hybridization for oxygen generation reaction according to the present invention overcomes the scaling limit between catalyst intermediate adsorption and product desorption and solves the problem of secondary reactions unnecessarily occurring in terms of catalyst activity. there is

1 is a flow chart showing a method for preparing a p-d orbital hybrid single metal atom catalyst for oxygen generation reaction according to an embodiment of the present invention.

2 is a LSV polarization curve graph of a single metal atom catalyst in the form of a hybrid p-d orbital for oxygen generation reaction according to an embodiment of the present invention.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings. However, the technology disclosed in this application is not limited to the embodiments described herein and may be embodied in other forms. However, the embodiments introduced herein are provided so that the disclosed content can be thorough and complete and the spirit of the present application can be sufficiently conveyed to those skilled in the art. In the drawing, in order to clearly express the components of each device, the size of the components, such as width or thickness, is shown somewhat enlarged.

In addition, although only some of the components are shown for convenience of description, those skilled in the art will be able to easily grasp the remaining components. When describing the drawings as a whole, it is described from the observer's point of view, and when an element is referred to as being located above or below another element, this means that the element is located directly above or below another element, or an additional element is interposed between them. It includes all possible meanings. In addition, those skilled in the art will be able to implement the spirit of the present application in various other forms without departing from the technical spirit of the present application. Also, like reference numerals in a plurality of drawings denote substantially the same elements.

In addition, singular expressions should be understood to include plural expressions, unless the context clearly indicates otherwise, and terms such as 'include' or 'have' refer to the described feature, number, step, operation, component, It is intended to indicate that a part or combination thereof exists, but it should be understood that the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded.

In addition, in performing a method or manufacturing method, each process constituting the method may occur in a different order from the specified order unless a specific order is clearly described in context. That is, each process may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

Hereinafter, the present invention will be described in more detail.

One aspect of the present invention, a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction, is a catalyst support formed by doping a metal material with a p-block element and formed on the surface of the catalyst support. It contains a single layer of metal atoms. The p-d orbital hybrid single metal atom catalyst for oxygen generation reaction of the present invention is hybridized between the p-orbital of the catalyst carrier (p-block element) and the d-orbital of the noble metal (d-block element), Compared to this, the oxygen generation reaction efficiency is increased, and the amount of noble metal catalyst used can be drastically reduced.

The metal material is, for example, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, La, Zr, Hf, Nb, Ta, Mo, W, Tc, Re, Ru, Os, Rh, Ir, Pd, Pt, Ag, Au, Cd, Hg, Ga, Ge, In, Sn, Sb, Tl, Pb, Bi, one or more metals from the lanthanides and actinides, or combinations thereof can include Preferably, Ti (titanium) metal may be included.

The Ti (titanium) metal may be used as a support for forming a catalyst support with a purity of more than 99.5% Pure Ti. The Ti (titanium) metal serves as a substrate and can be used as an electrochemical catalyst by providing an electrocatalyst conduction band that does not exist in a single atom.

The p-block element is a material used for doping the metal material and has a p-orbital, so that when a single metal atomic layer is formed, the catalyst intermediate is adsorbed through orbital hybridization with the d-orbital of the noble metal. Intensity can be independently controlled and out of scaling limits.

The p-block element may include any one of C (carbon), N (nitrogen), and O (oxygen), which is light in volume and capable of doping through gas, and for example, TiX ( TiC, TiN, TiO ₂ ) supports may be formed. More preferably, a TiC (titanium carbide) support may be formed by including C.

In embodiments, the material forming the single metal atomic layer may be a noble metal-based metal. In addition, the noble metal-based metal may be any one of gold, silver, platinum, palladium, rhodium, ruthenium, and iridium.

The noble metal-based metal is a material used for deposition on the catalyst support and has a d-orbital. When forming a single metal atom layer, the adsorption strength of the catalyst intermediate is independently controlled through orbital hybridization with the p-orbital of the catalyst support. and out of scaling limits.

The noble metal-based d-block element may be, for example, any one of gold, silver, platinum, palladium, rhodium, ruthenium, and iridium. The noble metal-based metal has a d-orbital as a d-block element, and may exhibit various characteristics depending on the combination of elements when the orbital is mixed with a p-block element. For example, it is possible to know the unique conduction band, valence conduction band, and electronic structure, realize high-efficiency oxygen generation reaction characteristics such as improvement of oxygen generation reaction overvoltage, and reduce the amount of noble metal catalyst used.

In embodiments, the thickness of the single metal atomic layer may be 0.1 nm to 2 nm. Preferably, it may be deposited to a thickness of 0.2 nm to 1.9 nm, more preferably to a thickness of 0.3 nm to 1.8 nm. When the deposition thickness is within the range, there is an advantage in that high-efficiency oxygen generation reaction characteristics such as improvement of oxygen generation reaction overvoltage can be realized.

The p-d orbital hybridized single-metal atom catalyst for oxygen generation reaction according to the present invention is a noble metal through hybridization between the p-orbital of a catalyst carrier (p-block element) and the d-orbital of a noble metal-based metal (d-block element). The oxygen generation reaction efficiency is increased compared to the supported amount, and the amount of noble metal catalyst used can be drastically reduced.

Another aspect of the present invention, a method for producing a single metal atom catalyst in the form of a p-d orbital hybrid for oxygen generation reaction, comprises the steps of doping a metal material with a p-block element to form a catalyst carrier (S100) and forming a single metal atomic layer having a thickness of 0.1 nm to 2 nm by depositing a noble metal-based metal on the catalyst carrier (S200).

1 is a flow chart showing a method for preparing a p-d orbital hybrid single metal atom catalyst for oxygen generation reaction according to the present invention.

Referring to FIG. 1, the method for preparing a single atom catalyst of the present invention includes a step of forming a catalyst carrier (S100) and a step of forming a single metal atom layer (S200).

The catalyst support forming step (S100) is performed for the purpose of forming a catalyst support for a p-d orbital hybrid single metal atom catalyst for oxygen generation reaction by doping a metal material with a p-block element. .

The p-block element may include, for example, C (carbon), N (nitrogen), and O (oxygen), which are light in volume and can be doped through gas, for example, TiX (TiC, TiN, TiO ₂ ) A support may be formed. It may preferably include C, and may form, for example, a TiC (titanium carbide) support.

The titanium carbide (TiC) may be formed by heat treatment at 1000 to 1200° C. for 200 to 400 seconds. Preferably, it may be formed by heat treatment at 1050 to 1150 ° C. for 250 to 350 seconds. During heat treatment within the above condition range, doping may be evenly applied to the surface by removing impurities without requiring a separate post-process.

The catalyst carrier may be a carbon carrier (TiC) having a large specific surface area and high crystallinity. For example, the catalyst support is a carbon support, graphene, graphene oxide, fullerene, carbon nanotube (CNT), carbon nanofiber, carbon nano It may include a carbon nanobelt, carbon nanoonion, carbon nanohorn, activated carbon, graphite, and the like. However, it is not necessarily limited to these, and may include all as long as it can be used as a carbon carrier in the art.

The catalyst carrier may have a structure such as a spherical shape, a rod shape, a tube shape, a cone shape, or a plate shape. However, it is not necessarily limited to this structure and may include any structure that can be used as a catalyst support in the art.

The catalyst support may be porous. For example, the catalyst carrier may be a porous carbon material having pores and a large specific surface area. For example, the catalyst carrier may be mesoporous. For example, some or all of the catalyst supports of various types described above may be porous.

In the single metal atom layer forming step (S200), a noble metal-based metal is deposited on the catalyst carrier to form a p-d orbital hybridized single metal atom catalyst for oxygen generation reaction through orbital hybridization between p-orbital and d-orbital. performed for a purpose

In embodiments, the material forming the single metal atomic layer may be a noble metal-based metal. In addition, the noble metal-based metal may be any one of gold, silver, platinum, palladium, rhodium, ruthenium, and iridium. Since the noble metal-based metal has a d-orbital, when forming a single metal atomic layer, the adsorption strength of the catalyst intermediate can be independently controlled through orbital hybridization with the p-orbital of the catalyst carrier and can be out of the scaling limit.

The noble metal-based d-block element may be, for example, any one of gold, silver, platinum, palladium, rhodium, ruthenium, and iridium. The noble metal-based metal has a d-orbital as a d-block element, and may exhibit various characteristics depending on the combination of elements when the orbital is mixed with a p-block element. For example, by orbital hybridization, a unique conduction band, valence conduction band, electronic structure, etc. can be found, and also, high-efficiency oxygen generation reaction characteristics such as improvement of oxygen generation reaction overvoltage can be realized, and the amount of noble metal catalyst used can be reduced.

The deposition is, for example, arc discharge, thermal chemical vapor deposition, plasma synthesis, high temperature plasma, plasma enhanced chemical vapor deposition , laser evaporation, laser ablation, vapor phase growth, or electronic-beam evaporator. Preferably, it may be performed by an electronic-beam evaporator process.

The deposition may be performed at 0.1 to 0.5 Å/s at 20 to 30°C. Preferably, it may be deposited at 0.2 to 0.4 Å/s at 23 to 27°C. When depositing in the above temperature and speed ranges, the deposition reaction uniformly occurs at a constant speed, so that a target single metal atomic layer can be well formed.

In a specific example, the thickness of the single metal atom layer made of iridium deposited in the step of forming the single metal atom layer may be 0.1 nm to 2 nm. When the deposition thickness is within the range, there is an advantage in that high-efficiency oxygen generation reaction characteristics such as improvement of oxygen generation reaction overvoltage can be implemented.

The p-d orbital hybrid single metal atom catalyst for oxygen generation reaction prepared by the production method of the present invention has a p-orbital of the catalyst support (p-block element) and a d-orbital of a noble metal (d-block element). Through inter-orbital hybridization, it has excellent characteristics of realizing high-efficiency oxygen generation reaction characteristics such as improvement of oxygen generation reaction overvoltage and drastically reducing the amount of noble metal catalyst used.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention by this in any sense.

Contents not described herein can be technically inferred by those skilled in the art, so descriptions thereof will be omitted.

(Example 1)

Titanium carbide, a catalyst support, was prepared by doping Ti metal with p-block element carbon (C). At this time, it was prepared by heat treatment at 1100° C. for 300 seconds in a methane (C ₄ H ₄ ) atmosphere using an induction heater.

Next, a d-block element, iridium (Ir), which is a precious metal, was deposited on the titanium carbide carrier using an E-beam to form a single metal atom layer. At this time, the deposition was carried out at room temperature by adjusting the rate to 0.3 Å/s, and the thickness was deposited at 0.5 nm.

Through the above process, a p-d orbital hybrid single metal atom catalyst (TiC-Ir) for oxygen generation reaction according to the present invention was finally completed (TiC-Ir deposited at 0.5 nm).

(Example 2)

In Example 2, a single atom catalyst was completed in the same manner as in Example 1, except that Ir (iridium) was deposited on the catalyst carrier to a thickness of 1.0 nm when forming the single atom catalyst (1 nm deposited TiC-Ir). .

(Example 3)

In Example 3, a single atom catalyst was completed in the same manner as in Example 1, except that Ir (iridium) was deposited on the catalyst carrier to a thickness of 1.5 nm when forming the single atom catalyst (1.5 nm deposited TiC-Ir ).

(Example 4)

Example 4 is a comparative example to Examples 1 to 3, and a commercial catalyst, Bulk Ir, was used without using a single atom catalyst (Bulk Ir).

Then, for the p-d orbital hybrid type single metal atom catalyst for oxygen evolution reaction of the present invention according to Examples 1 to 3 and the existing commercial catalyst according to Example 4 presented as a comparative example, OER activity was evaluated as follows. performed.

First, a three-electrode cell for the RDE experiment was constructed using the catalyst prepared in each of the above examples, and the OER polarization curve was measured under normal temperature and pressure conditions. Then, the potential at a constant current density (10 mA/cm ² ) was measured from the obtained polarization curve.

The overall experimental conditions are as follows. A Rotating Disk Electrode (RDE) was used as the working electrode, Ag/AgCl was used as the reference electrode, and Pt Wire was used as the counter electrode. At this time, the electrolyte was 0.1 M HClO4 (pH 1), the temperature was carried out at room temperature 25 ℃ conditions.

In addition, experiments were performed under the following conditions to evaluate OER activity. The electrolyte was purged with argon for 30 minutes, and the working electrode was rotated at 1600 rpm to remove oxygen in the OER. At this time, the scan rate was maintained at 10 mV / s and the scan range was 0.05 V (vs RHE) to 2.00 V (vs RHE), and the reaction was repeated from 1 to 10 times for each experiment.

Experimental results for this are specifically disclosed in Table 1 and FIG. 2 below.

	샘플 명sample name	과전압 (첫번째 분극곡선)overvoltage (first polarization curve)	과전압 (열번째 분극곡선)overvoltage (tenth polarization curve)
실시예1Example 1	Bulk IrBulk Ir	1.6521.652	··
실시예2Example 2	Ir 0.5 nm on TiCIr 0.5 nm on TiC	1.604 V vs RHE1.604 V vs RHE	측정불가not measurable
실시예3Example 3	Ir 1 nm on TiCIr 1 nm on TiC	1.592 V vs RHE1.592 V vs RHE	1.571 V vs RHE1.571 V vs RHE
실시예4Example 4	Ir 2 nm on TiC Ir 2 nm on TiC	1.557 V vs RHE1.557 V vs RHE	1.534 V vs RHE1.534 V vs RHE

2 is a LSV polarization curve graph of a pd orbital hybrid single metal atom catalyst for oxygen generation reaction according to an embodiment of the present invention. Referring to FIG. 2, compared to iridium bulk (Bulk Ir), a conventional commercial catalyst, the sample deposited with 0.5 nm of iridium showed a 2.99% increase in oxygen generation reaction overvoltage at a current density of 10 mAcm-2, but as the reaction was repeated, The overvoltage decreased, and in the tenth experiment, the overvoltage could not be read at 10 mAcm ^-2 .

In addition, the overvoltage of the sample deposited with 1 nm of iridium was improved by about 3.63% and the sample with 2 nm of iridium was improved by about 5.75%. As the oxygen generation reaction experiment was repeated, the iridium layer was oxidized to become iridium oxide. As a result, the overpotential of the oxygen generation reaction gradually increased, and after the iridium was completely oxidized, the overpotential value did not increase any more and was maintained.

Through this, as in the present invention, in the case of a single atom catalyst comprising orbital hybridization between the p-orbital of the catalyst carrier (p-block element) and the d-orbital of the noble metal-type metal (d-block element), oxygen evolution reaction It was able to confirm the excellent characteristics of realizing high-efficiency oxygen generation reaction characteristics such as improvement of overvoltage and further reducing the amount of noble metal catalyst used drastically.

As described above, the single atom catalyst according to the present invention through the physical property evaluation experiment example uses an orbital hybridized p-d orbital hybridized single atom catalyst in contrast to the conventional invention, thereby overcoming the scaling limit between catalyst intermediate adsorption and product desorption, It was confirmed that there is an effect of solving the secondary reaction problem that occurs unnecessarily in terms of catalytic activity.

On the other hand, although the present invention has been described with limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions can be made by those skilled in the art in the field to which the present invention belongs. It is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to the claims.

Claims

a catalyst carrier formed by doping a metal material with a p-block element; and

A single metal atom layer formed on the surface of the catalyst carrier; a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction comprising:
The method of claim 1,

The metal material forming the catalyst support is titanium,

The p-block element is any one of carbon, nitrogen and oxygen, a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction.
The method of claim 1,

The material forming the single metal atom layer is a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction, characterized in that the noble metal-based metal.
The method of claim 3,

The noble metal-based metal is any one of gold, silver, platinum, palladium, rhodium, ruthenium and iridium.
According to any one of claims 1 to 4,

The single metal atom catalyst of the p-d orbital hybrid type for oxygen generation reaction, characterized in that the thickness of the single metal atom layer is 0.1 nm to 2 nm.
Forming a catalyst carrier by doping a metal material with a p-block element; and

Forming a single metal atom layer having a thickness of 0.1 nm to 2 nm by depositing a noble metal-based metal on the catalyst carrier;
The method of claim 6,

The metal material forming the catalyst support is titanium,

Wherein the p-block element is any one of carbon, nitrogen and oxygen.
The method of claim 6,

A method for producing a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction, characterized in that the material forming the single metal atom layer is a noble metal-based metal.
The method of claim 8,

The noble metal-based metal is any one of gold, silver, platinum, palladium, rhodium, ruthenium and iridium.
The method of claim 7,

Forming the catalyst support is,

When the metal material is titanium and the p-block element is carbon,

A method for producing a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction, characterized in that the titanium metal is heated in a methane atmosphere through a heater to generate titanium carbide (TiC) on the surface.
The method of claim 8,

The step of forming the single metal atom layer,

When the metal material is titanium and the p-block element is carbon,

A method for producing a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction, characterized in that a single metal atom layer is formed by depositing iridium on a catalyst carrier made of titanium doped with titanium carbide on its surface.
The method of claim 11,

A method for producing a p-d orbital hybrid type single metal atom catalyst for oxygen generation reaction, characterized in that the thickness of the single metal atom layer made of iridium deposited in the step of forming the single metal atom layer is 0.1 nm to 2 nm.