KR102164892B1 - Titanium dioxide with worm-like structure, method for manufacturing the same and use thereof - Google Patents

Abstract

The present invention relates to titanium dioxide in an anatase crystal phase having excellent electron transfer ability by having a primary particle size of 10 nm or less and a high specific surface area due to a worm-like structure, and its use.

Description

Titanium dioxide with worm-like structure, method for manufacturing the same and use thereof

The present invention relates to titanium dioxide and its use, which has a worm-like structure and a high specific surface area, thereby having excellent electron transfer capability.

In general, titanium dioxide (TiO ₂ ) is manufactured and sold in various sizes of nanoparticles having a spherical or similar shape.

Nano-sized titanium dioxide particles having a small size decrease the electron transfer ability due to numerous grain-boundary between the particles when manufactured with a photocatalyst and a photoelectron transfer electrode, and the small particle size also causes harm to the human body. There may be a problem of recall.

Conversely, titanium dioxide particles having a large size of hundreds of nanometers and microns are somewhat advantageous in terms of excellent electron transfer ability and harmfulness to the human body, but a problem in that the specific surface area is rapidly decreased may occur.

Accordingly, there is a need for development of titanium dioxide that is harmless to the human body and can be recovered and has a high specific surface area and excellent electron transfer capability.

[Patent Document 1] Korean Patent Publication No. 10-2017-0135793 [Patent Document 2] Korean Patent Publication No. 10-2006-0012020

An object of the present invention is to provide titanium dioxide having an excellent electron transfer ability by having a worm-like structure and a high specific surface area.

In addition, another object of the present invention is to provide a photocatalyst comprising titanium dioxide of the present invention.

In addition, another object of the present invention is to provide an electrode for a solar cell comprising titanium dioxide of the present invention.

In order to achieve the above object, titanium dioxide according to the present invention may have a particle diameter of 10 nm or less and may be an anatase crystal phase having a worm-like structure.

The titanium dioxide can be prepared by a manufacturing method comprising the following steps:

(a) dissolving the branched copolymer and glucose in each solvent, and then mixing to prepare a mixed solution;

(b) adding a titanium tetrachloride sol containing titanium tetrachloride, an acid and an alcohol to the mixed solution, followed by hydrothermal reaction to obtain titanium dioxide; And

(c) sintering the titanium dioxide at high temperature.

In the step (a), the branched copolymer may be a copolymer in which a hydrophilic monomer is grafted onto the main chain of a halogenated polymer compound.

In the step (b), the mixing ratio (v/w) of the sol containing titanium tetrachloride: the branched copolymer may be 1:0.05 to 0.2.

In the step (b), the weight mixing ratio of the titanium tetrachloride: acid: alcohol may be 1:0.5 to 1:1 to 3.

In the step (b), the acid may be selected from the group consisting of hydrochloric acid, sulfuric acid and nitric acid.

In the step (b), the alcohol may be selected from the group consisting of ethanol, methanol, isopropyl alcohol and propanol.

In step (b), the alcohol may be ethanol.

In the step (b), the hydrothermal reaction may be performed at 100 to 200°C for 15 to 24 hours,

In the step (c), the high-temperature sintering may be performed at 400 to 550° C. for 0.5 to 3 hours.

In the present invention, a photocatalyst comprising titanium dioxide of the present invention is provided.

In addition, the present invention provides an electrode for a solar cell including titanium dioxide of the present invention.

Titanium dioxide according to the present invention has a high specific surface area due to an anatase crystal phase in which the primary particles have a small particle diameter of 10 nm or less and have a worm-like structure, thereby having an excellent electron transfer ability effect.

Titanium dioxide according to the present invention can be applied to various uses such as photocatalysts and photoelectrodes such as solar cell electrodes.

1 is a view showing SEM images (a) and enlarged images (b) of titanium dioxide particles of Example 1 and Comparative Examples 1 to 3;
FIG. 2 is a diagram showing a high magnification image of an SEM of titanium dioxide particles of Example 1. FIG.
3 is a graph showing the crystal structure of titanium dioxide particles of Example 1 and Comparative Examples 1 to 3 through XRD analysis.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to specific examples described below in detail together with the accompanying drawings. However, the present invention is not limited to the specific examples disclosed below, but may be implemented in various different forms, and only the specific examples of the present invention make the disclosure of the present invention complete, and in the technical field to which the present invention pertains. It is provided to fully inform a person of ordinary skill in the scope of the invention, and the invention is only defined by the scope of the claims.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

Hereinafter, titanium dioxide according to the present invention will be described in detail.

Titanium dioxide according to the present invention may be an anatase crystal phase having a primary particle having a particle diameter of 10 nm or less and having a worm-like structure.

The titanium dioxide is composed of small particles and pores because the size of the primary particles is less than 10 nm, it is easy to form a worm-like structure, and thus can have a very high specific surface area.

Titanium dioxide of the present invention forms a long-connected structure where the male nanoparticles of primary particles are gathered, and this structure is a worm-like, that is, a porosity of a two-dimensional structure such as a wire or a rod. Since it has an anatase-based crystal structure, it has a very high specific surface area and is an organically connected structure. The photoactive properties are high compared to the spherical rutile titanium dioxide particles, so when applied to a photocatalyst or solar cell electrode, excellent photolysis properties and electron transfer ability can be exhibited.In addition, when used as a catalyst, it can be easily recovered by a filter. . In addition, since the worm-like structure has a linear shape in which the shape is irregularly bent, it is not regularly arranged, and large secondary pores can be formed between the structures. By using this, when manufacturing an electrode or a photocatalytic filter, the ease of penetration of materials may increase.

Titanium dioxide according to the present invention can be prepared by a manufacturing method comprising the following steps:

(a) preparing a mixed solution by mixing a solution in which the branched copolymer is dissolved in a first solvent and a solution in which glucose is dissolved in a second solvent;

(b) adding a titanium tetrachloride sol containing titanium tetrachloride, an acid and an alcohol to the mixed solution, followed by hydrothermal reaction to obtain titanium dioxide; And

(c) sintering the titanium dioxide at high temperature.

In the step (a), the branched copolymer may be a copolymer in which a hydrophilic monomer is grafted onto the main chain of a halogenated polymer compound, but is not limited thereto.

More preferably, the branched copolymer may be polyvinyl chloride (a copolymer obtained by grafting poly (ethylene glycol) methyl ether (meth) acrylate (POEM) to PVC) (PVC-g-POEM), which It may be represented by the following Formula 1.

[Formula 1]

The matrix made of the branched copolymer is a copolymer having a main chain of a halogenated polymer compound having excellent mechanical properties and having excellent mechanical properties and a branched chain of polyethylene glycol having a strong interaction with a titanium tetrachloride precursor. When used, it is possible to prepare titanium dioxide particles of a worm-like structure.

In the step (a), the branched copolymer may be prepared by a manufacturing method preferably comprising the following steps:

(i) dissolving the halogenated polymer compound in a solvent to prepare a halogenated polymer compound solution; And

(ii) adding and reacting a solution containing a hydrophilic monomer to the halogenated polymer compound solution to obtain a branched copolymer.

In the step (i), the halogenated polymer compound is not particularly limited, and for example, polyvinylidene fluoride-co-chlorotrifluoroethylene, polyvinyl chloride, polychlorotrifluoroethylene, polydichlorodifluoro It may be one or more selected from the group consisting of romethane, polyvinylidene dichloride, and copolymers thereof.

In the step (ii), the hydrophilic monomer is not particularly limited, for example, polyoxyethylene (meth) acrylate, poly (ethylene glycol) methyl ether (meth) acrylate, hydroxyethyl (meth) acrylate , Hydrolyzed t-butyl (meth)acrylate, acrylamide, N-vinylpyrrolidone, aminostyrene, styrene sulfonic acid, methylpropene sulfonic acid, sulfopropyl (meth)acrylate, sulfoethyl (meth)acrylic It may be one or more selected from the group consisting of rate and sulfobutyl (meth)acrylate.

In step (ii), the weight mixing ratio of the halogenated polymer compound: the hydrophilic monomer is preferably 1:9 to 9:1, and more preferably 3:7 to 7:3.

In the reaction of step (ii), a catalyst and/or a ligand may be further added, and the catalyst is not particularly limited, and may be, for example, at least one selected from CuCl, CuCl ₂ and CuBr, and the ligand is specifically There is no limitation, for example, 1,1,4,7,10,10-hexamethyltriethylenetetraamine, tris[2-(dimethylamino)ethyl]amine, tris(2-pyridylmethyl)amine, N, It may be one or more selected from N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine and 2,2'-bipyridyl.

In step (ii), the reaction is preferably performed by atomic transfer radical polymerization (ATRP). This is one method of controlled free radical polymerization, which keeps the free radical concentration low and concentrates it mainly on the polymer main chain, thereby controlling the concentration of free radicals, and many unwanted side reactions It can be prevented from occurring.

The first solvent used in step (a) is not particularly limited in its kind as long as it is an organic solvent in which the branched copolymer is dissolved, and tetrahydrofuran or the like may be preferably used.

The second solvent used in step (a) is not particularly limited in its kind as long as it is a solvent in which glucose is dissolved, and water (H ₂ O) may be preferably used.

In the step (a), the weight ratio of the glucose: the branched copolymer is preferably 1:0.01 to 0.35. If it is out of the above range, the worm-like particles are not produced and spherical particles may be produced, Rutile-based crystal structures may be produced, which is not preferable.

In the step (b), the mixing ratio (v/w) of the sol containing titanium tetrachloride: the branched copolymer is preferably 1:0.05 to 0.2, more preferably 1:0.1 to 0.15. If it is out of range, it may not be possible to obtain more connected, worm-like structure of titanium dioxide particles of anatase type, so excellent electrons of titanium dioxide of two-dimensional structure such as wire or rod Cannot have the ability to deliver.

In the step (b), the weight mixing ratio of the titanium tetrachloride: acid: alcohol is not particularly limited, and may be, for example, 1:0.5 to 1:1 to 3, preferably 1:0.5:2. If it is within the range, a two-dimensional worm-like structure may be formed while the particles are connected.

The acid is not particularly limited, and may be, for example, at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and the like, preferably hydrochloric acid.

The alcohol is not particularly limited, and may be, for example, one or more selected from the group consisting of ethanol, methanol, isopropyl alcohol, propanol, and the like, preferably ethanol.

In the step (b), the hydrothermal reaction is preferably performed at 100 to 200°C for 15 to 24 hours, more preferably at 130 to 170°C for 17 to 22 hours, the hydrothermal reaction temperature is 100 If the temperature is less than °C, the temperature is not sufficient for the formation of crystalline particles, and the anatase phase is not formed, which is not preferable. If the temperature exceeds 200°C, excessive energy consumption occurs when reacting at a high temperature, which is not economically preferable. If the hydrothermal reaction time is less than 15 hours, unreacted particles are formed together because there is not enough time to control the shape of the particles, and in the case of reaction for more than 24 hours, warm-like particles have already formed and are more than necessary. Energy consumption is undesirable.

The hydrothermal reaction may be carried out in a sealed reactor, preferably in a hydrothermal synthesis reactor.

In the step (c), the high-temperature sintering may be performed at 400 to 550° C. for 0.5 to 3 hours.

In the step (c), the high-temperature sintering is preferably performed at 400 to 550°C for 0.5 to 3 hours, preferably at 400 to 500°C for 1 to 2 hours, at a temperature lower than the above range. It is not preferable because the purity of the produced particles may be reduced because all organic impurities are not removed at and time, and at temperatures and times higher than the above range, excessive energy consumption due to high temperature treatment is caused, and it is effective because it is unnecessary excessive reaction. It is not desirable.

According to the present invention, there is provided an electrode for a photocatalyst or solar cell containing the titanium dioxide.

Hereinafter, preferred examples are presented to aid in the understanding of the present invention, but the following examples are only illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

Examples and Comparative Examples

[material]

Tetrahydrofuran (THF), glucose, titanium tetrachloride, titanium isopropoxide, hydrochloric acid, tetraethylorthosilicate, aluminum isopropoxide, polyvinyl chloride (PVC, normal-methylpi) used in the following Examples and Comparative Examples Rolidone (NMP), poly(ethylene glycol) methyl ether (meth) acrylate (POEM), copper chloride, 1,1,4,7,10,10-hexamethyltriethylenetetraamine (HMTETA), toluene and ethanol Was purchased from Sigma-Aldrich, and was used without purification.

<Method of measuring properties>

1) shape analysis

In order to confirm the shape and size of the titanium dioxide particles of Example 1 and Comparative Examples 1 to 3, a field emission scanning electron microscope (FE-SEM, Transmission Electron Microscopy) analysis was performed.

2) Crystallinity evaluation

In order to confirm the crystallinity of the titanium dioxide particles of Example 1 and Comparative Examples 1 to 3, X-ray diffraction (XRD, x-ray diffraction) analysis was performed.

<Production Example: Preparation of branched copolymer>

6 g of polyvinyl chloride (PVC) was completely dissolved in 50 ml of normal-methylpyrrolidone (NMP), and then 24 ml of poly(ethylene glycol) methyl ether (meth) acrylate (POEM), 0.10 g of CuCl, 1,1 0.24 ml of ,4,7,10,10-hexamethyltriethylenetetraamine (HMTETA) was added, followed by mixing and stirring. Nitrogen was injected during stirring for 30 minutes, and then reacted in a stirrer at 90° C. for 24 hours. Methanol was added to the mixed solution after the reaction was completed, precipitated, and filtered to recover the PVC-g-POEM branched copolymer. At this time, the process of synthesizing the copolymer was carried out by an atomic transfer radical polymerization (ATRP) method. At this time, the weight mixing ratio of PVC:POEM was 7:3.

<Example 1>

In the contents shown in Table 1 below, the PVC-g-POEM branched copolymer obtained in Preparation Example was dissolved in THF, and glucose was separately dissolved in 4 ml of DI water, and the two solutions were then mixed. . Subsequently, a sol containing titanium tetrachloride prepared by mixing titanium tetrachloride, hydrochloric acid (HCl) and ethanol (hereinafter, also referred to as Ti sol) was added to the obtained mixed solution, followed by stirring at room temperature for 1 hour and then 150°C. It was reacted in a hydrothermal reactor for 20 hours. Then, the prepared titanium dioxide particles were washed, dried, and then heat treated at 500° C. for 1 hour (high temperature sintering) to remove residual organic matter, and the particle diameter of titanium dioxide was measured, and the results are shown in Table 1 below. And the SEM image of the titanium dioxide particles is also shown in FIG. 1.

<Comparative Example 1>

Titanium dioxide was prepared in the same manner as in Example 1, except that the PVC-g-POEM branched copolymer and ethanol were not used, and the particle diameter of the titanium dioxide was measured, and the results are shown in Table 1 below, The SEM image of the titanium dioxide particles is also shown in FIG. 1.

<Comparative Example 2>

Titanium dioxide was prepared in the same manner as in Example 1, except that the PVC-g-POEM branched copolymer was not used, and the particle diameter of the titanium dioxide was measured, and the results are shown in Table 1 below. The SEM image of the titanium particles is also shown in FIG. 1.

<Comparative Example 3>

Titanium dioxide was prepared in the same manner as in Example 1, except that 0.3 g of the PVC-g-POEM branched copolymer was used instead of 0.2 g, and the particle diameter of the titanium dioxide was measured, and the results are shown in Table 1 below. And the SEM image of the titanium dioxide particles is also shown in FIG. 1.

THF
(ml) PVC-POEM
(g) Glucose
(g) TiCl ₄
(ml) Hydrochloric acid
(HCl)
(ml) ethanol
(ml) shape Crystal phase
(crystallinity) Secret
area
(㎡/g) Example 1 36 0.2 0.8 0.4 0.2 0.8 Worm-like Anatase About 90 Comparative Example 1 36 - 0.8 0.4 0.2 - Nanoparticles Anatase About 60 Comparative Example 2 36 - 0.8 0.4 0.2 0.8 Non-spherical Anatase About 60 Comparative Example 3 36 0.3 0.8 0.4 0.2 0.8 Warm Like + Old Anatase + Rutile About 80

As shown in Table 1, the titanium dioxide of Example 1 has a high specific surface area of 90 m 2 /g or more due to the anatase crystal phase having a worm-like structure. In contrast, it can be seen that the titanium dioxide of Comparative Examples 1 to 3 does not have a worm-like structure and has a low specific surface area.

Claims (11)

A method for producing titanium dioxide in anatase crystal phase having a worm-like structure, comprising the following steps:
(a) dissolving the branched copolymer and glucose in each solvent, and then mixing to prepare a mixed solution;
(b) adding a titanium tetrachloride sol containing titanium tetrachloride, an acid and an alcohol to the mixed solution, followed by hydrothermal reaction at 100 to 200°C for 15 to 24 hours to obtain titanium dioxide; And
(c) sintering the titanium dioxide at high temperature. The method of claim 1,
The titanium dioxide is a method for producing titanium dioxide having a primary particle diameter of 10 nm or less. The method of claim 1,
In the step (a), the branched copolymer is a method of producing titanium dioxide, which is a copolymer in which a hydrophilic monomer is grafted onto a main chain of a halogenated polymer compound. The method of claim 1,
In the step (b), the sol containing titanium tetrachloride: the mixing ratio (v/w) of the branched copolymer is 1:0.05 to 0.2. The method of claim 1,
In the step (b), the weight mixing ratio of the titanium tetrachloride: acid: alcohol is 1:0.5 to 1:1 to 3. The method for producing titanium dioxide. The method of claim 1,
In the step (b), the acid is a method for producing titanium dioxide selected from the group consisting of hydrochloric acid, sulfuric acid and nitric acid. The method of claim 1,
In the step (b), the alcohol is a method for producing titanium dioxide selected from the group consisting of ethanol, methanol, isopropyl alcohol and propanol. The method of claim 1,
In the step (b), the alcohol is ethanol, a method for producing titanium dioxide. The method of claim 1,
In the step (c), the high-temperature sintering is performed at 400 to 550°C for 0.5 to 3 hours. The method according to any one of claims 1 to 9,
The titanium dioxide is used in a photocatalyst, a method for producing titanium dioxide. The method according to any one of claims 1 to 9,
The titanium dioxide is used in an electrode for a solar cell, a method for producing titanium dioxide.

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