KR20240031074A - Fibrous composite structure catalyst - Google Patents

Abstract

The present disclosure relates to a fibrous composite structure catalyst, comprising: a fiber substrate; and a composite catalyst coating layer supported on the substrate and including a porous support including mesopores and gold nanoparticles incorporated into the pores of the porous support. It includes, and the composite catalyst provides a fibrous composite structure catalyst that oxidizes harmful gases and converts them into chemically stable species.

Description

Fibrous composite structure catalyst}

The present disclosure relates to a fibrous composite structure catalyst with significantly improved catalytic activity.

Transition metal nanoparticles can exhibit catalytic activity due to their high specific surface area, but since transition metal nanoparticles are primary particles and typically have an average particle size of 20 nm or less, the pore size is 2 nm to 50 nm to support these nanoparticles. ㎚ mesoporous support is considered preferable. The mesoporous support can be made of a metal oxide material, commonly known as silica, aluminosilicate, or titania. Depending on the manufacturing method, mesopores of various sizes and shapes can be formed, and the metal or quasi-skeleton forming the skeleton can be used as a mesoporous support. By adjusting the metal content, the concentration of acid sites and ion exchange ability can also be adjusted. Accordingly, mesoporous supports are being used as carriers for transition metal nanoparticles, and due to the characteristics of mesopores, the diffusion resistance of the material is lower than that of microporous supports, so it can have the advantage of a faster reaction rate.

However, the mesoporous support on which transition metal nanoparticles are supported is manufactured from powder particles, and when such powder particles are used as a catalyst, a pressure differential problem occurs as the catalytic reaction progresses. Therefore, in order to alleviate the differential pressure problem and apply it to a commercial catalytic reaction process, catalyst powder particles must be supported on a substrate of a certain size or larger. In other words, even if a highly active catalyst is developed, it is essential to scale it up to suit the application environment in order to finally commercialize it.

As an example to solve this problem, a method of using a honeycomb monolith structure as a base for catalyst powder has been proposed. However, the honeycomb monolith structure has a very small specific surface area of 1.0 m2/g or less, so there is a problem in that the amount of catalyst that can be supported is small, and accordingly, there is a limitation in reducing the catalytic reaction efficiency. In addition, existing substrates such as honeycomb monolith structures lack flexibility due to material characteristics and cannot be manufactured into various shapes, which limits their application areas.

Therefore, there is a need to develop a new type of composite catalyst that can be applied in various shapes by lowering the differential pressure while providing flexibility.

US 2019-0255520 A1 (2019.08.22)

One purpose of the present disclosure is to provide a fibrous composite structure catalyst that has significantly excellent catalytic activity at room temperature and at the same time can significantly alleviate the pressure differential problem that occurs at high flow rates when using existing powder catalysts.

Another object of the present disclosure is to provide a fibrous composite structure catalyst that can be applied to products of various shapes due to its flexible material that can simultaneously have excellent catalytic activity and structural stability.

The present disclosure relates to fiber substrates; and a composite catalyst coating layer supported on the substrate and including a porous support including mesopores and gold nanoparticles incorporated into the pores of the porous support. It includes, and the composite catalyst provides a fibrous composite structure catalyst that oxidizes harmful gases and converts them into chemically stable species.

In one embodiment, the fiber substrate has air permeability and may have an average fiber diameter of 0.5 to 10 ㎛.

In one embodiment, the fibrous composite structure catalyst may further include a binder between the fiber substrate and the composite catalyst coating layer.

In one embodiment, the binder may include a water-soluble polymer binder.

In one embodiment, the fibrous composite structure catalyst may further include a silicate adhesive layer between the fiber substrate and the composite catalyst coating layer.

In one embodiment, the silicate adhesive layer may be derived from a compound represented by Chemical Formula 1 below.

[Formula 1]

Si(OR ₁ ) _n (R ₂ ) _4-n

In Formula 1, R ₁ is a C1 to C4 alkyl group, and R ₂ is independently a C1 to C10 alkyl group, -L-NH ₂ , -L-OR ₃ , -L-COOH, or glycidoxyC1-C8 alkyl. , L is C1 to C8 alkylene, R ₃ is C1 to C4 alkyl, and n is an integer of 2 to 4.

In one embodiment, the fiber substrate may include any one or a combination of two or more selected from the group consisting of non-woven fabric, fabric, and knitted fabric.

In one embodiment, the fiber substrate may include any one or a combination of two or more selected from the group consisting of glass fiber, ceramic fiber, and metal fiber.

In one embodiment, the fiber substrate includes inorganic particles and organic fibers, and the inorganic particles are any one or a combination of two or more selected from the group consisting of metal organic framework (MOF), zeolite, activated carbon, and potassium permanganate. You can.

In one embodiment, the porous support may be a metal oxide or metalloid oxide porous support.

In one embodiment, the diameter distribution function obtained by Fourier transforming the extended X-ray absorption fine structure (EXAFS) spectrum of the composite catalyst may satisfy Equation 1 below.

[Equation 1]

(DH2/DH1) < 0.3

In the above equation 1, DH1 is the height of the peak at the interatomic distance D1, DH2 is the peak height at the interatomic distance D2, and D1 and D2 satisfy the following equations 2 and 3, respectively.

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

In Equation 2 and Equation 3 above, D3 refers to the interatomic distance of the Au-Au bond in the bulk phase existing at 2.8 to 3.0 Å.

In one embodiment, the diameter distribution function obtained by Fourier transforming the extended X-ray absorption fine structure (EXAFS) spectrum of the composite catalyst may satisfy Equation 4 below.

[Equation 4]

(DA2/DA1) < 0.25

In Equation 4, DA1 is the area of the peak at the interatomic distance D1, DA2 is the area of the peak at the interatomic distance D2, and D1 and D2 satisfy Equation 2 and Equation 3 above, respectively.

In one embodiment, the composite catalyst may have a bimodal peak in the interatomic distance range of 2.2 Å to 3.0 Å of the diameter distribution function.

In one embodiment, the fibrous composite structure catalyst may be used for an oxidation reaction of carbon monoxide, an aldehyde-based compound, or a hydrocarbon-based compound.

In addition, the present disclosure includes (S1) preparing a fiber substrate; (S2) preparing a dispersion containing a porous support including mesopores and a composite catalyst including gold nanoparticles incorporated into the pores of the porous support; (S3) applying the dispersion to the surface of the fiber substrate; and (S4) drying the dispersion; A method for producing a fibrous composite structure catalyst comprising a is provided.

The fibrous composite structure catalyst according to the present invention has significantly excellent catalytic activity at room temperature and at the same time can significantly alleviate the “differential pressure” problem that occurs at high flow rates when using existing powder catalysts.

The fibrous composite structure catalyst according to the present invention can be applied to products of various shapes due to its flexible material that can simultaneously have excellent catalytic activity and structural stability.

Figure 1 shows a diameter distribution function obtained by Fourier transforming the EXAFS spectrum of a composite catalyst according to one embodiment.
Figure 2 shows an image of a fibrous composite structure catalyst according to one embodiment.

Unless otherwise defined, the technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art to which this invention pertains, and the gist of the present invention is summarized in the following description and accompanying drawings. Descriptions of known functions and configurations that may unnecessarily obscure are omitted.

Additionally, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly dictates otherwise.

In addition, units used without special mention in this specification are based on weight, and as an example, the unit of % or ratio means weight % or weight ratio, and weight % refers to the amount of any one component of the entire composition unless otherwise defined. It refers to the weight percent occupied in the composition.

In addition, the numerical range used in this specification includes the lower limit and upper limit and all values within the range, increments logically derived from the shape and width of the defined range, all double-defined values, and the upper limit of the numerical range defined in different forms. and all possible combinations of the lower bounds. Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

The term 'comprise' in this specification is an open description with the same meaning as expressions such as 'comprising', 'contains', 'has' or 'characterized by', and includes elements that are not additionally listed, Does not exclude materials or processes.

The present inventor recognized that even if catalytic activity is high, when using a powdered catalyst, a pressure differential problem occurs at a high flow rate, making it difficult to commercialize a highly active catalyst. In addition, although the differential pressure can be reduced when using composite catalyst particles coated on a substrate as a solution to this problem, the existing substrate has a disadvantage in that it cannot be used in products of various shapes due to lack of flexibility due to the material characteristics. As a result of in-depth research to solve this problem, the present inventor discovered that a composite catalyst carrying a composite catalyst containing a porous support and gold nanoparticles on a fiber substrate can solve the above-mentioned problems while realizing better catalytic activity. and completed the present invention.

The fibrous composite structure catalyst according to the present disclosure includes a fiber substrate; and a composite catalyst supported on the substrate, comprising a porous support including mesopores and gold nanoparticles incorporated into the pores of the porous support; It includes, and the composite catalyst is characterized in that it oxidizes harmful gases and converts them into chemically stable species.

The fibrous composite structure catalyst according to the present disclosure can improve the differential pressure problem, which is one of the causes of reduced lifespan of the filter, by supporting the composite catalyst having excellent catalytic activity on a fiber substrate. In addition, unlike existing substrates, it has the advantage of being applicable to products of more diverse shapes by having a flexible fiber form.

According to one embodiment, the fiber substrate has air permeability and may have an average diameter of 0.5 ㎛ to 10 ㎛, specifically 1 ㎛ to 5 ㎛, more specifically 1 ㎛ to 3 ㎛. The fibrous composite structure catalyst according to one embodiment may have superior catalytic activity and differential pressure improvement effects by supporting the composite catalyst on a fiber substrate having the above-mentioned physical properties.

According to one embodiment, the fiber substrate may have a thickness of 0.01 to 100 mm, 0.1 to 50 mm, or 0.5 to 20 mm, but is not limited thereto.

According to one embodiment, the fiber substrate may have an areal density of 1 g/m2 to 1000 g/m2, 10 g/m2 to 500 g/m2, or 20 g/m2 to 100 g/m2, but is limited thereto. no.

According to one embodiment, the fiber substrate may have an air permeability of 300 seconds/100mL or less, 100 seconds/100mL or less, 100 seconds/100mL or less, or 20 seconds/100mL or less, and the lower limit is not particularly limited, but is an example. It may be 0.1 second/100mL or 1 second/100mL, but is not limited thereto. The air permeability degree may be the air permeability degree based on an air permeability test based on JIS P-8117.

According to one embodiment, the loading amount of the composite catalyst is 1 g/㎡ or more, 10 g/㎡ or more, 100 g/㎡ More than 1,000 g/㎡ Below, 750 g/㎡ It may be less than or equal to 500 g/m2, for example 1 g/m2. to 1,000 g/m2, specifically 10 g/m2 to 750 g/m2, more specifically 100 g/m2 It may be from 500 g/m2, but is not limited thereto.

According to one embodiment, the ratio (Y/X) of the supported amount Y (g/m 2) of the composite catalyst to the areal density However, it is not limited to this.

According to one embodiment, a binder may be further included between the fiber substrate and the composite catalyst coating layer. Accordingly, a structurally stable fibrous composite structure catalyst can be provided by increasing the adhesion between the composite catalyst coating layer and the fiber substrate.

Specifically, the binder may include an inorganic binder, an organic binder, or a combination thereof, and more specifically, an organic binder may be used.

According to a preferred embodiment, the binder may include a water-soluble polymer binder, and the water-soluble polymer binder is one or two selected from the group consisting of polyethylene glycol, polyvinyl alcohol, and poly(N-vinyl pyrrolidone). It could be more than that. The weight average molecular weight of the water-soluble polymer binder may be 10,000 to 1,000,000 g/mol, but is not limited thereto. More specifically, the binder may be polyvinyl alcohol, which allows the composite catalyst to be firmly bound to the fiber substrate and exhibit excellent durability.

According to another embodiment, a silicate adhesive layer may be further included between the fiber substrate and the composite catalyst coating layer. Accordingly, the fibrous composite structure catalyst according to one embodiment can exhibit superior durability by increasing the adhesion between the composite catalyst coating layer and the fiber substrate.

In one embodiment, the silicate adhesive layer may be derived from a compound represented by Chemical Formula 1 below.

[Formula 1]

Si(OR ₁ ) _n (R ₂ ) _4-n

In Formula 1, R ₁ is a C1 to C4 alkyl group, and R ₂ is independently a C1 to C10 alkyl group, -L-NH ₂ , -L-OR ₃ , -L-COOH, or glycidoxyC1-C8 alkyl. , L is C1 to C8 alkylene, R ₃ is C1 to C4 alkyl, and n is an integer of 2 to 4.

In a specific example, in Formula 1, R ₁ is a C1 to C4 alkyl group, and n may be 4.

According to one embodiment, the fiber substrate may include any one or a combination of two or more selected from the group consisting of non-woven fabric, woven fabric, and knitted fabric, and may specifically be a non-woven fabric. The non-woven fabric includes spun-bonded non-woven fabric, spunlace non-woven fabric, melt-blown non-woven fabric, and thermally bonded non-woven fabric. fabric, dry laying non-woven fabric, needle punching nonwoven fabric, stitch bond non-woven fabric, and chemical bond non-woven fabric. It may be any one selected from the group or two or more of them.

According to one embodiment, the material of the fiber base may be an organic fiber, an inorganic fiber, or an organic-inorganic composite fiber.

The organic fiber may include polyolefin-based polymer, polyester-based polymer, polyamide-based polymer, polyimide-based polymer, polytetrafluoroethylene polymer, polyacrylonitrile polymer, or a combination thereof. For example, the organic fibers include polyethylene, polypropylene, polyisobutylene, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, nylon, polyimide, polytetrafluoroethylene, and polyacrylonitrile. It may include at least one selected from the group consisting of

The inorganic fiber may include any one or a combination of two or more selected from the group consisting of glass fiber, ceramic fiber, and metal fiber.

The organic-inorganic composite fiber may include inorganic particles and organic fibers, and the inorganic particles may be any one or a combination of two or more selected from the group consisting of metal organic framework (MOF), zeolite, activated carbon, and potassium permanganate. .

According to one embodiment, the porous support may be a metal oxide or metalloid oxide porous support. The metal or metalloid of the metal oxide or metalloid oxide may be from Groups 2 to 5, Group 7 to 9, and Group 11 to 14, and is specifically selected from Groups 2 to 4, Group 13, and Group 14. It may be a metal or metalloid, and more specifically, it may be Al, Ti, Zr, or Si.

The porous support includes mesopores and may optionally further include micropores. In the present disclosure, micropore means that the average diameter of internal pores is less than 2 ㎚, and mesopore (Mesopore) means that the average diameter of internal pores is 2 ㎚ to 50 ㎚. The volume of mesopores of the porous support may be 50 volume% or more, 60 volume% or more, or 70 volume% or more, and the upper limit is not limited, but for example, 100 volume% or less, 95 volume% or less, or 90 volume% or less. It may be 50 to 100% by volume, specifically 60 to 90% by volume, but this is only an example and is not limited thereto.

According to one non-limiting example, the porous support may have a hierarchical porous structure, and may include a structure in which micropores are regularly present between mesopores and are interconnected.

According to a non-limiting example, the porous support may further include macro pores, and the inclusion of macro pores above a certain volume fraction may significantly reduce gas diffusion resistance, which may be preferable.

The gold nanoparticles can be manufactured from methods known in the art or commercially available materials can be used. Specifically, gold nanoparticles can be produced by reducing a gold precursor present in a solution to gold according to a known method (Natan et al., Anal. Chem. 67, 735 (1995)). Examples of gold precursors include gold-containing halides, nitrates, acetates, acetylacetonates, or ammonium salts, but are not limited thereto. Specifically, the gold precursor may be HAuCl ₄ or HAuBr ₄ , but is not limited thereto.

The diameter of the gold nanoparticles may be 1 nm to 20 nm, specifically 1 nm to 15 nm, and more specifically 1 nm to 12 nm. A preferred diameter of gold nanoparticles may be 1 nm to 10 nm, more preferably 1 nm to 8 nm.

According to one embodiment, the average diameter of the nanoparticles may be larger than the average diameter of mesopores of the porous support. Accordingly, it is possible to create a deformation of the crystal lattice of the gold nanoparticles incorporated into the mesopores of the porous support, and to improve catalytic activity in the room temperature range.

According to one embodiment, the nanoparticles may be incorporated into all of the mesopores of the porous support or may be incorporated into a portion of the mesopores of the porous support, and specifically, may be incorporated into a portion of the mesopores of the porous support. there is. More specifically, the nanoparticles may be irregularly incorporated into some of the mesopores of the porous support. At this time, the structure embedded in all of the mesopores of the porous support refers to a superlattice structure, and specifically refers to a highly ordered superlattice structure with face-centered cubic (FCC) symmetry. can do. On the other hand, the shape in which nanoparticles are irregularly incorporated into a portion of the mesopores has the advantage that gas diffusion can be significantly improved compared to the superlattice structure.

According to one embodiment, the nanoparticles may be incorporated into a portion of the mesopores of the porous support, and the mesopores not incorporated into the nanoparticles may be connected to each other through open pores. In the fibrous composite structure catalyst, nanoparticles are incorporated into only a portion of the pores of the porous support, so that harmful gases can be more effectively diffused through pores that are not incorporated by nanoparticles connected to each other through open pores. Accordingly, the catalytic reaction rate of harmful gases within the composite catalyst can be increased.

According to one embodiment, the composite catalyst may have an average particle diameter of 0.01 ㎛ to 10 ㎛, specifically 0.05 ㎛ to 5 ㎛, more specifically 0.1 ㎛ to 5 ㎛, and by satisfying the above range, on the fiber substrate It can be bonded more closely to improve durability.

According to one embodiment, the gold nanoparticles may be included in 0.1 to 10% by weight of the total weight of the catalyst coating layer, specifically 0.5 to 7% by weight, and more specifically 1 to 5% by weight. It may be.

According to one embodiment, the gold nanoparticles may be included in 0.005 to 3.5% by weight of the total weight of the fibrous composite structure catalyst, specifically 0.01 to 3% by weight, and more specifically 0.05 to 2.5% by weight. Alternatively, it may be included at 0.1 to 1.8 weight%.

According to one embodiment, the composite catalyst includes a porous support including mesopores and gold nanoparticles incorporated into the pores of the porous support, and the east diameter obtained by Fourier transforming the EXAFS (Extended X-ray absorption fine structure) spectrum. The radial distribution function may satisfy Equation 1 below.

[Equation 1]

(DH2/DH1) < 0.3

In equation 1, DH1 is the height of the peak at the interatomic distance D1, DH2 is the height of the peak at the interatomic distance D2, and D1 and D2 are expressed in the following equations 2 and 3, respectively. Satisfies. Specifically, D1 and D2 are the interatomic distances of the maximum peak found in a range that satisfies the following Equations 2 and 3, respectively.

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

In Equations 2 and 3 above, D3 refers to the interatomic distance of the Au-Au bond in the bulk phase that exists at 2.8 to 3.0 Å, and may specifically exist at 2.88 to 2.98 Å, and more specifically, the standard of 2.90 Å. It may mean the distance between atoms. Specifically, D3 refers to the interatomic distance of the Au-Au bond in the bulk at 2.8 to 3.0 Å, obtained through peak deconvolution when the peak appears as a single peak with asymmetry or has a bimodal peak. can do. The asymmetry means that although the peak has the shape of a single peak (unimodal peak), the left and right sides have asymmetry based on the center of the peak as two peaks overlap.

Specifically, (D1/D3) in Equation 2 may be 0.85 to 0.92, and (D2/D3) in Equation 3 may be 0.63 to 0.66.

According to one embodiment, in Equation 1, DH1 may mean the height of the peak at an interatomic distance of 2.57 ± 0.2 Å, and DH2 may mean the height of the peak at an interatomic distance of 1.85 ± 0.2 Å. there is. Specifically, DH1 may refer to the peak height of an interatomic distance of 2.57 ± 0.1 Å, and DH2 may refer to the peak height of an interatomic distance of 1.85 ± 0.1 Å.

As the composite catalyst satisfies the height ratio of the peak at the interatomic distance D1 and the peak at the interatomic distance D2 of less than 0.3, the catalytic activity can be significantly improved.

EXAFS stands for extended X-ray absorption fine structure, and can analyze the diameter distribution or coordination number of gold nanoparticles. For example, when high-energy X-rays are irradiated to gold atoms, the gold atoms contained in the gold nanoparticles emit electrons. Accordingly, radial scattered waves are generated centered on the gold atom that has absorbed the X-rays, and when the electrons emitted from the gold atom that has absorbed the Electrons are emitted. At this time, radial scattered waves are generated centered on other adjacent atoms.

The scattered waves generated around the gold atom that absorbed the X-rays and the scattered waves generated around other adjacent atoms (gold or oxygen atoms) interfere. At this time, a standing wave is obtained depending on the distance between the gold atom that absorbed the X-rays and another atom (gold or oxygen atom) adjacent to the gold atom. When the standing wave is Fourier transformed, a radius distribution having a peak depending on the distance between a gold atom and another atom (gold or oxygen atom) adjacent to the gold atom is obtained. That is, not only the peak according to the distance between the gold (Au) atom and the gold (Au) atom, but also the distance between the gold (Au) atom with the Au-O bond and the oxygen atom when the gold (Au) atom has a bond with the oxygen atom. A diameter distribution with a peak according to can be obtained.

According to one embodiment, (DH2/DH1) in Equation 1 may be 0.25 or less, more specifically 0.24 or less, and may be non-limitingly 0 or more. Preferably, (DH2/DH1) in Equation 1 may be 0.2 or less, and more preferably 0.15 or less. Having the above numerical range is desirable in that the catalytic activity of the composite catalyst is significantly improved and substantially all of the reactant gas contained in the gas stream can be converted to product gas remarkably quickly.

According to one embodiment, the composite catalyst may have a radial distribution function obtained by Fourier transforming an extended X-ray absorption fine structure (EXAFS) spectrum that satisfies Equation 4 below.

[Equation 4]

(DA2/DA1) < 0.25

In Equation 4, DA1 is the area of the peak at the interatomic distance D1, DA2 is the area of the peak at the interatomic distance D2, and D1 and D2 satisfy Equation 2 and Equation 3 above, respectively.

In Equation 4, DA1 may refer to the area of the peak with an interatomic distance of 2.57 ± 0.2 Å, and DA2 may refer to the area of the peak with an interatomic distance of 1.85 ± 0.2 Å. Specifically, DA1 may refer to the area of the peak with an interatomic distance of 2.57 ± 0.1 Å, and DA2 may refer to the area of the peak with an interatomic distance of 1.85 ± 0.1 Å.

As the composite catalyst satisfies the area ratio of the peak at the interatomic distance D1 and the peak at the interatomic distance D2 of less than 0.25, the catalytic activity can be significantly improved.

According to one embodiment, (DA2/DA1) in Equation 4 may be 0.2 or less, specifically 0.18 or less, more specifically 0.15 or less, and may be indefinitely 0 or more. Preferably, (DA2/DA1) in Equation 4 may be 0.1 or less, and more preferably 0.08 or less. Having the above numerical range is desirable in that the catalytic activity of the composite catalyst is significantly improved and substantially all of the reactant gas contained in the gas stream can be converted to product gas remarkably quickly.

The numerical ranges of Equations 1 and 2 obtained from the EXAFS (Extended X-ray absorption fine structure) spectrum can be derived from the manufacturing process of the improved composite catalyst according to the present invention, and through an embodiment of the present disclosure Although it can be implemented, the numerical range of Equations 1 and 2 above is not limited to one embodiment.

According to one embodiment, the diameter distribution function obtained by Fourier transforming the EXAFS (Extended Au) - Appears by bonds between gold (Au) atoms. Specifically, the interatomic distance range of 2.2 to 3.0 Å may be a range where the distance between gold (Au) atoms is located, and refers to the distribution of the interatomic distance of Au-Au in the crystal lattice.

In the interatomic distance range of 2.2 to 3.0 Å, typical gold nanoparticles can exhibit a single peak, and having a single peak means that the distance between gold (Au)-gold (Au) atoms in the crystal lattice of the nanoparticle is It means that it is constant. However, having a bimodal peak may mean that different distances between gold (Au) and gold (Au) atoms exist in the crystal lattice. Although it has not been clearly identified, it may be related to the deformation of the crystal lattice due to compressive stress. It is inferred that two different distances between gold (Au) and gold (Au) atoms were created. As it has a positive peak in the interatomic distance range of 2.2 to 3.0 Å, it can exhibit very excellent catalytic activity even in low temperature regions, and can convert substantially all of the reactant gas contained in the gas stream at high flow rate into product gas very quickly. It is desirable in that it can be done.

According to one embodiment, the fibrous composite structure catalyst may be used for the oxidation reaction of carbon monoxide, aldehyde-based compounds, or hydrocarbon-based compounds. Accordingly, the fibrous composite structure catalyst according to the present disclosure can be preferably used as a solid-phase oxidizing agent for carbon monoxide, aldehyde-based compounds, or hydrocarbon-based compounds. The aldehyde-based compound may be acetaldehyde or formaldehyde, but is not limited thereto. The hydrocarbon-based compound may be an aliphatic or aromatic compound or a volatile organic compound (VOC), and examples include, but are not limited to, methane, ethane, propane, butane, benzene, toluene, or xylene.

The method for producing a fibrous composite structure catalyst according to the present disclosure includes the steps of (S1) preparing a fiber substrate; (S2) preparing a dispersion containing a porous support including mesopores and a composite catalyst including gold nanoparticles incorporated into the pores of the porous support; (S3) applying the dispersion to the surface of the fiber substrate; and (S4) drying the dispersion; It is characterized by including.

In the method for producing the fibrous composite structure catalyst, the order of steps S1 and S2 is not limited, and the above-described provisions can be applied to the fiber substrate, porous support, and nanoparticles, so a detailed description thereof is provided. Omit it.

To improve durability, in step S2, the dispersion may further include a binder. The binder may include an inorganic binder, an organic binder, or a combination thereof, and preferably includes an organic binder. More preferably, the binder may include a water-soluble polymer binder, and the water-soluble polymer binder may be any one or two or more selected from the group consisting of polyethylene glycol, polyvinyl alcohol, and poly(N-vinyl pyrrolidone). . The weight average molecular weight of the water-soluble polymer binder may be 10,000 to 1,000,000 g/mol, but is not limited thereto. More specifically, the binder may be polyvinyl alcohol, which allows the composite catalyst to be firmly bound to the fiber substrate and exhibit excellent durability.

According to another embodiment for improving durability, before step S3, impregnating the fiber substrate with a solution for forming a silicate adhesive layer containing a compound represented by the following Chemical Formula 1, a catalyst, and a solvent; and forming a silicate adhesive layer on the fiber substrate by a condensation reaction of a compound represented by the following formula (1); may further include.

[Formula 1]

Si(OR ₁ ) _n (R ₂ ) _4-n

In Formula 1, R ₁ is a C1 to C4 alkyl group, and R ₂ is independently a C1 to C10 alkyl group, -L-NH ₂ , -L-OR ₃ , -L-COOH, or glycidoxyC1-C8 alkyl. , L is C1 to C8 alkylene, R ₃ is C1 to C4 alkyl, and n is an integer of 2 to 4.

According to one embodiment, the step of drying the fiber substrate on which the silicate adhesive layer is formed may be further included.

The catalyst contained in the solution for forming the silicate adhesive layer may be an acid catalyst, and the acid catalyst may be selected from, for example, hydrochloric acid, nitric acid, sulfuric acid, and acetic acid. In addition, solvents used in the solution for forming the silicate adhesive layer include water, lower alcohols such as ethanol, methanol, and propanol, dimethylformamide, acetone, tetrahydrofuran, diethyl ether, methylene chloride, and N-methyl-2-p. It can be selected from rolidone, hexane, cyclohexane, etc., but is not necessarily limited thereto.

The dispersion may have a slightly acidic pH of 2 to 6 or pH 3 to 5. The solvent of the dispersion is not particularly limited, but may be, for example, water, alcohol, or a combination thereof.

In step S3, the dispersion may be applied to the surface of the fiber substrate using a coating method known in the art, such as spin coating, spray coating, knife coating, roll coating, inkjet printing, or dip coating.

According to one embodiment, the step of vacuum drying the fibrous composite structure catalyst prepared in steps S1 to S4 may be further included after step S4. The drying temperature may be 30°C to 100°C, specifically 40°C to 80°C, but is not particularly limited thereto.

Hereinafter, examples and experimental examples will be described in detail below. However, the examples and experimental examples described below are only illustrative of some, and the technology described in this specification is not limited thereto.

<Preparation Example 1> Preparation of composite catalyst 1

[Step 1]: Preparation of gold nanoparticles functionalized with polymer

[Step 1-1]: Gold nanoparticles stabilized with oleylamine are synthesized according to the following procedure.

First, olein amine was selected as a stabilizer, and a solution consisting of 60 ml of tetralin, 60 ml of oleinamine, and 0.6 g of HAuCl·H ₂ O was prepared by stirring at room temperature for 10 minutes. 6 mmol of TBAB (tetrabutylammonium bromide), 6 ml of tetralin, and 6 ml of oleyl amine were mixed by ultrasonic pulverization and quickly added to the solution. Then, the solution was stirred at room temperature for another hour, ethanol was added, and then centrifuged to precipitate gold nanoparticles. The gold nanoparticle precipitate was redispersed with hexane, ethanol was added, and centrifuged. The prepared gold nanoparticles had an average particle diameter of 4 nm, and the prepared gold nanoparticles were dispersed as-formed in 100 ml of toluene.

[Step 1-2]: The surface of the gold nanoparticle is functionalized with thiolated PEG using the following method.

The gold nanoparticles dispersed in toluene in step 1-1 were diluted by adding an additional 100 ml of tetrahydrofuran, and a thiolated polymer was selected to functionalize the gold nanoparticles by binding them to the surface, and 1 g Monofunctional polyethylene glycol (aSH-PEG, weight average molecular weight: 1 kDa) whose terminal was substituted with a thiol group was added. After stirring, hexane was added and centrifuged to precipitate gold nanoparticles (4-Au-PEG) functionalized with PEG. 4-Au-PEG obtained by precipitation was dried and then dispersed in water.

[Step 2]: Preparation of porous silica containing PEG-functionalized gold nanoparticles

0.088 g of 4-Au-PEG prepared in steps 1-2 above was mixed with 0.396 g of Pluronic F127 as an activator and dispersed uniformly in 10 ml of 1.6 M HCl aqueous solution, and then 1.49 g of tetraethylortho was added to the dispersion. Silicate (TEOS) was added. Then, the dispersion of the mixture was stirred for 15 minutes and maintained without stirring at room temperature for 40 hours to prepare a red precipitate. The red precipitate thus formed corresponds to porous silica containing PEG-functionalized gold nanoparticles.

[Step 3]: Preparation of composite catalyst

The red precipitate prepared in the previous step was washed with water, dried, and then calcined step by step for 3 hours at 250 ℃, 2 hours at 400 ℃, and 2 hours at 500 ℃ to remove PEG and Pluronic F127 polymer, thereby producing gold nanoparticles. A captured porous silica composite catalyst was prepared.

<Preparation Example 2> Preparation of composite catalyst 2

The same steps were performed except that gold nanoparticles with an average particle diameter of 10 nm were prepared by adjusting the molar ratio of oleinamine and HAuCl·H ₂ O in step 1-1 of Preparation Example 1, thereby producing gold nanoparticles. A composite catalyst 2 containing porous silica was prepared.

<Preparation Example 3> Preparation of composite catalyst 3

The same steps 1 and 2 were performed except that gold nanoparticles with an average particle diameter of 12 nm were prepared by adjusting the molar ratio of oleinamine and HAuCl·H ₂ O in step 1-1 of Preparation Example 1. In step 3, the red precipitate prepared in the previous step was washed with water, dried, and calcined at 450°C to remove PEG and Pluronic F127 polymer, thereby preparing porous silica composite catalyst 3 with trapped gold nanoparticles.

<Preparation Example 4> Preparation of composite catalyst 4

Composite catalyst 4 was prepared by performing steps 1 and 3 in the same manner, except that step 2 of Preparation Example 1 was performed as follows.

For the preparation of porous alumina containing PEG-functionalized gold nanoparticles in step 2, first prepare 0.15 g of PEG-functionalized gold nanoparticles (4-Au-PEG) and 0.675 g of Pluronic F127, and dissolve them in nitric acid (68% ) After uniformly dispersing in a mixed solution of 0.8 ml and 40 ml of ethanol, 0.81 g of aluminum ethoxide was added to the dispersion. Then, the dispersion of the mixture was stirred for 3 hours, maintained at room temperature for 24 hours without stirring, and then dried at 60°C for 3 hours to prepare a red solid. Thereafter, step 3 of Preparation Example 1 was performed in the same manner to prepare porous alumina composite catalyst 4 containing gold nanoparticles.

<Preparation Example 5> Preparation of composite catalyst 5

Composite catalyst 5 was prepared by performing steps 1 and 3 in the same manner, except that step 2 of Preparation Example 1 was performed as follows.

For the preparation of porous titania containing PEG-functionalized gold nanoparticles in step 2, first prepare 0.10 g of PEG-functionalized gold nanoparticles (4-Au-PEG) and 0.44 g of Pluronic F127 and dissolve them in 37% hydrochloric acid. After uniformly dispersing in a mixed solution of 0.68 ml and 17.05 ml of ethanol, 2.28 g of titanium tetraisopropoxide was added to the dispersion. Then, the dispersion of the mixture was stirred for 3 hours, maintained at room temperature for 24 hours without stirring, and then dried at 60°C for 3 hours to prepare a red solid. Thereafter, step 3 of Preparation Example 1 was performed in the same manner to prepare porous titania composite catalyst 5 in which gold nanoparticles were captured.

<Preparation Example 6> Preparation of composite catalyst 6

In step 2 of Preparation Example 1, the same steps were performed except that 0.396 g of Pluronic F127 was not used, thereby preparing porous silica composite catalyst 6 in which gold nanoparticles were captured in a superlattice structure.

<Example 1> Preparation of fibrous composite structure catalyst 1

A dispersion was prepared by mixing the composite catalyst 1 prepared in Preparation Example 1 in an aqueous solution to 10% by weight and milling. The average particle diameter of the milled composite catalyst powder was 0.8 ㎛. Acetic acid was added to the dispersion to adjust the pH to 4, and polyvinyl alcohol, an organic binder, was mixed with the dispersion to make 2% by weight of the dispersion to prepare a slurry for coating.

The coating slurry was dip-coated on the surface of a polyethylene terephthalate (PET) nonwoven fabric for 5 minutes, and the excess slurry was removed by blowing air and dried sufficiently. The immersion and drying process was repeated 10 times, and the coated nonwoven fabric was vacuum dried at 60°C for 4 hours to finally prepare the fibrous composite structure catalyst 1.

<Example 2> Preparation of fibrous composite structure catalyst 2

Fibrous composite structure catalyst 2 was prepared in the same manner as in Example 1, except that composite catalyst 2 prepared in Preparation Example 2 was used instead of composite catalyst 1 prepared in Preparation Example 1.

<Example 3> Preparation of fibrous composite structure catalyst 3

Fibrous composite structure catalyst 3 was prepared in the same manner as in Example 1, except that composite catalyst 3 prepared in Preparation Example 3 was used instead of composite catalyst 1 prepared in Preparation Example 1.

<Example 4> Preparation of fibrous composite structure catalyst 4

Fibrous composite structure catalyst 4 was prepared in the same manner as in Example 1, except that composite catalyst 6 prepared in Preparation Example 6 was used instead of composite catalyst 1 prepared in Preparation Example 1.

<Example 5> Preparation of fibrous composite structure catalyst 5

Instead of the PET nonwoven fabric of Example 1, a nonwoven fabric with a silicate adhesive layer formed in a manner described later was used. Specifically, PET nonwoven fabric was impregnated in a solution consisting of 30 g of tetraethyl orthosilicate (TEOS), 70 g of distilled water, and 5 g of 1M hydrochloric acid (HCl) and reacted at 60°C for 2 hours. A coating slurry containing 2% by weight of composite catalyst powder dispersed in water was dip coated on the surface of the PET nonwoven fabric with the semi-hardened silicate adhesive layer for 5 minutes, and then the excess slurry was removed by blowing air and dried sufficiently. The soaking and drying process was repeated 10 times, and the coated nonwoven fabric was dried at 80° C. for 12 hours to finally prepare the fibrous composite structure catalyst 5.

<Comparative Example 1>

The following experimental example was performed using the same amount of powdered composite catalyst 1 prepared in Preparation Example 1 as in Example 1.

<Comparative Example 2>

The following experimental example was performed using PET nonwoven fabric without the composite catalyst powder coated in Example 5 and with a silicate adhesive layer formed thereon.

<Comparative Example 3>

A fibrous composite structure catalyst was prepared in the same manner as in Example 1, except that gold particles with an average particle diameter of 4 nm were used instead of the composite catalyst 1 prepared in Preparation Example 1.

<Experimental Example 1> EXAFS (Extended X-ray absorption fine structure) analysis

EXAFS (Extended X-ray absorption fine structure) measurements were performed using the 4C and 10C beamlines of the Pohang Accelerator (PLS-II). The EXAFS spectrum was Fourier transformed to obtain a radial distribution function. Figure 1 (a) shows a composite catalyst on which gold particles with an average particle diameter of 4 nm are supported (Preparation Example 1), Figure 1 (b) shows a composite catalyst on which gold particles with an average particle diameter of 10 nm are supported (Preparation Example 2), Figure 1(c) shows the diameter distribution function of the composite catalyst (Preparation Example 3) supported with gold particles with an average particle diameter of 12 nm.

As a result of analyzing the diameter distribution function of the composite catalyst particles according to Preparation Examples 1 to 5, a peak due to Au-O bond was observed in the range of 1.4 to 1.7 Å in all cases. From this, the proximity between the surface of the gold nanoparticles and the porous silica that captures them provides conditions for forming stable Au-O bonds at the interface between the gold nanoparticles and the porous silica, resulting in Au-O-Si, Au-O-Al Alternatively, it can be confirmed that Au-O-Ti is formed.

In addition, in all of Preparation Examples 1 to 5, a peak due to bulk Au-Au bond was observed in the 2.8 to 3.0 Å range, and when the interatomic distance of this peak is called D3, the peak of the diameter distribution function based on D3 defined. Specifically, D1 and D2 are the interatomic distances of the maximum peak found in a range that satisfies the following equations 2 and 3, respectively, and the positions of D1, D2, and D3 are shown in Table 1. In addition, the ratio of the height (DH1) and area (DA1) of the peak at the interatomic distance D1 and the height (DH2) and area (DA2) of the peak at the interatomic distance D2 were calculated and shown in Table 1.

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

Manufacturing Example 1 Production example 2 Production example 3 Production example 4 Production example 5 DH2/DH1 0 0.227 0.335 0 0 DA2/DA1 0 0.129 0.227 0 0 D1 2.5522Å 2.5893Å 2.567Å 2.5607Å 2.5939Å D2 - 1.8471Å 1.848Å - - D3 2.906Å 2.8967Å 2.8177Å 2.9601Å 2.9526Å D1/D3 0.8783 0.894 0.911 0.8651 0.8785 D2/D3 - 0.638 0.656 - -

<Experimental Example 2> Desorption rate evaluation

A desorption rate experiment of the fibrous composite structure catalyst according to Examples 1 and 5 was performed. The fibrous composite structure catalyst was immersed in an aqueous solution, vibrated in an ultrasonic cleaner at 400 Watts, then completely dried to remove moisture, and then the weight of the fibrous composite structure catalyst before and after ultrasonic treatment was measured. The detachment rate was measured by varying the ultrasonic treatment time, and the detachment rate was calculated as the weight loss of the fibrous composite structure catalyst divided by the total weight, and the results are listed in Table 2 below.

Sonication time 20 minutes 40 minutes 60 minutes 120 minutes 180 minutes Example 1 0.7% One% 1.8% 2.0% 2.1% Example 5 0.6% 0.8% 1.3% 1.4% 1.5%

Referring to Table 2, the fibrous composite structure catalysts according to Examples 1 and 5 showed a very low desorption rate. In particular, it can be seen that Example 5, which additionally includes a silicate adhesive layer, has a better detachment rate than Example 1.

<Experimental Example 3> Catalytic activity evaluation

Catalytic activity was evaluated through acetaldehyde removal rate experiments in a closed space (gas bag). The catalyst according to Example 1 and Comparative Example 1 and the nonwoven fabric according to Comparative Example 2 were placed on a Petri-Dish in the gas bag, and acetaldehyde-containing gas was supplied into the gas bag, and then a gas detection tube (GASTEC 92L) was placed in the gas bag. The concentration of acetaldehyde over time was measured using this method. At this time, the acetaldehyde-containing gas used was a gas containing 10 ppm of acetaldehyde in the air, and all measurements were performed at room temperature (25°C). The experimental results are listed in Table 3 below.

hour 10 minutes 20 minutes 30 minutes 40 minutes 50 minutes 60 minutes Example 1 3 ppm 0.5ppm 0ppm 0 ppm 0ppm 0ppm Example 2 5 ppm 2ppm 0.5ppm 0 ppm 0ppm 0ppm Example 3 6 ppm 3.5 ppm 1.5ppm 0.5ppm 0ppm 0 ppm Example 4 7ppm 4.5ppm 2.5 ppm 1.5ppm 1 ppm 0.5ppm Example 5 2 ppm 0.5 ppm 0ppm 0ppm 0 ppm 0ppm Comparative Example 1 5 ppm 2.5 ppm 1.5ppm 1 ppm 0.5 ppm 0ppm Comparative Example 2 10 ppm 10ppm 10ppm 10 ppm 10 ppm 10 ppm Comparative Example 3 10 ppm 10ppm 10 ppm 10 ppm 10 ppm 10ppm

Referring to Table 3, it can be seen that when the fibrous composite structure catalysts of Examples 1 to 5 were used, the concentration of acetaldehyde decreased rapidly compared to the comparative example.

Examples 1 to 3, which included a composite catalyst with gold nanoparticles embedded in a portion of the surface of porous silica, had superior catalytic activity compared to Example 4, which included a composite catalyst with gold nanoparticles embedded in the entire surface of the porous silica. was found to have. This appears to have improved catalytic activity as metal nanoparticles were incorporated into some of the pores of the porous support, and the mesopores that were not impregnated with nanoparticles were connected to each other through open pores.

In addition, in the case of Example 1 containing a composite catalyst impregnated with gold nanoparticles with an average particle diameter of 4 nm, Example 2 and Examples containing a composite catalyst impregnated with gold nanoparticles with an average particle diameter of 10 nm or 12 nm It was found to have superior catalytic activity compared to 3.

<Experimental Example 4> Differential pressure evaluation

Differential pressure evaluation was performed in a tubular reactor open on both sides. The catalysts according to Examples 1 to 3 and Comparative Example 1 were installed in the middle of the tubular reactor, and pressure sensors were installed at the front of the reactor where harmful gases flow and at the rear of the reactor where harmful gases are oxidized and discharged into chemically stable species. Installed. While acetaldehyde-containing harmful gas was supplied at a constant flow rate to the front of the reactor, the pressure was measured by pressure sensors installed at the front and rear of the reactor, and the differential pressure was calculated. The pressure sensor used a known commercially available device. Acetaldehyde-containing harmful gas is a gas containing 10 ppm of acetaldehyde in the air, and all measurements were performed at room temperature (25°C). The differential pressure (mbar) according to the supply flow rate is listed in Table 4 below.

supply flow rate 80 ㎖/min 100 ml/min 120 ㎖/min 140 ㎖/min 160 ㎖/min 180 ㎖/min Example 1 0 0 0 0 0 0 Example 2 0 0 0 0 0 One Example 3 0 0 0 0 0 2 Comparative Example 1 35 44 53 61 70 78

Referring to Table 4, Examples 1 to 3 have a differential pressure of 0 or close to 0 and include a composite catalyst coating layer supported on the substrate, so that the differential pressure is significantly lower than that of Comparative Example 1 in powder form, and in particular, 140 It was confirmed that the differential pressure was low even at high flow rates of more than mL/min, more than 160 mL/min, or more than 180 mL/min.

As described above, the present disclosure has been described in the present specification using specific details and limited examples, but these are provided only to facilitate a more general understanding of the present disclosure, and the present disclosure is not limited to the above embodiments. Anyone skilled in the art can make various modifications and variations from this description.

Claims (15)

fiber substrate; and
A composite catalyst coating layer supported on the substrate and including a porous support including mesopores and gold nanoparticles incorporated into the pores of the porous support; Includes,
The composite catalyst is a fibrous composite structure catalyst that oxidizes harmful gases and converts them into chemically stable species.
The fibrous substrate has air permeability and an average fiber diameter of 0.5 to 10 ㎛, a fibrous composite structure catalyst.
According to paragraph 1,
A fibrous composite structure catalyst further comprising a binder between the fiber substrate and the composite catalyst coating layer.
According to paragraph 3,
The binder is a fibrous composite structure catalyst comprising a water-soluble polymer binder.
According to paragraph 1,
A fibrous composite structure catalyst further comprising a silicate adhesive layer between the fiber substrate and the composite catalyst coating layer.
According to clause 5,
The silicate adhesive layer is a fibrous composite structure catalyst derived from a compound represented by the following formula (1):
[Formula 1]
Si(OR ₁ ) _n (R ₂ ) _4-n
In Formula 1, R ₁ is a C1 to C4 alkyl group, and R ₂ is independently a C1 to C10 alkyl group, -L-NH ₂ , -L-OR ₃ , -L-COOH, or glycidoxyC1-C8 alkyl. , L is C1 to C8 alkylene, R ₃ is C1-C4 alkyl, and n is an integer of 2 to 4.
According to paragraph 1,
The fibrous substrate is a fibrous composite structure catalyst comprising one or a combination of two or more selected from the group consisting of non-woven fabric, woven fabric, and knitted fabric.
According to paragraph 1,
The fibrous substrate is a fibrous composite structure catalyst comprising any one or a combination of two or more selected from the group consisting of glass fiber, ceramic fiber, and metal fiber.
According to paragraph 1,
The fiber substrate includes inorganic particles and organic fibers, and the inorganic particles are any one or a combination of two or more selected from the group consisting of metal organic framework (MOF), zeolite, activated carbon, and potassium permanganate. Fibrous composite structure catalyst .
According to paragraph 1,
The porous support is a fibrous composite structure catalyst that is a metal oxide or metalloid oxide porous support.
According to paragraph 1,
A fibrous composite structure catalyst in which the diameter distribution function obtained by Fourier transforming the EXAFS (Extended X-ray absorption fine structure) spectrum of the composite catalyst satisfies the following equation 1:
[Equation 1]
(DH2/DH1) < 0.3
In the above equation 1, DH1 is the height of the peak at the interatomic distance D1, DH2 is the peak height at the interatomic distance D2, and D1 and D2 satisfy the following equations 2 and 3, respectively:
[Equation 2]
0.8≤(D1/D3)≤0.95
[Equation 3]
0.6≤(D2/D3)≤0.7
In Equations 2 and 3 above, D3 refers to the interatomic distance of the Au-Au bond in the bulk phase existing at 2.8 to 3.0 Å.
According to clause 11,
A fibrous composite structure catalyst in which the diameter distribution function obtained by Fourier transforming the EXAFS (Extended X-ray absorption fine structure) spectrum of the composite catalyst satisfies the following equation 4.
[Equation 4]
(DA2/DA1) < 0.25
In Equation 4, DA1 is the area of the peak at the interatomic distance D1, DA2 is the area of the peak at the interatomic distance D2, and D1 and D2 satisfy Equation 2 and Equation 3 above, respectively.
According to clause 11,
A fibrous composite structure catalyst having a bimodal peak in the interatomic distance range of 2.2 Å to 3.0 Å of the diameter distribution function.
According to paragraph 1,
The fibrous composite structure catalyst is a fibrous composite structure catalyst for the oxidation reaction of carbon monoxide, aldehyde-based compounds, or hydrocarbon-based compounds.
(S1) preparing a fiber substrate;
(S2) preparing a dispersion containing a porous support including mesopores and a composite catalyst including gold nanoparticles incorporated into the pores of the porous support;
(S3) applying the dispersion to the surface of the fiber substrate; and
(S4) drying the dispersion;
Method for producing a fibrous composite structure catalyst comprising.