KR101754776B1 - Photocatalyst complex comprising catechol derivatives polymers and method for preparing the same - Google Patents

Abstract

The present invention relates to a semiconductor photocatalyst and a photocatalytic composite including the visible light sensitive agent layer on the semiconductor photocatalyst. Thus, a low-cost photocatalytic composite having activity in the ultraviolet and visible regions can be provided. Also, a method for removing contaminants by removing contaminants under light irradiation in water using the photocatalytic composite of the present invention is provided, and a method for producing hydrogen peroxide which generates hydrogen peroxide can be provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a photocatalytic composite comprising a catechol-based polymer and a method for manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a photocatalytic composite and a method for producing the same, and more particularly, to a photocatalytic composite including catechol derivatives polymers and a method for producing the same.

The photocatalytic method of removing pollutants from the water is expected to be a clean technology that can solve the energy problem of the future because only the sunlight is used as the energy source. Titanium dioxide (TiO ₂ ) is a relatively inexpensive and stable semiconductor photocatalyst and has been widely used for the decomposition of aquatic pollutants because of its high oxidizing power. However, it has a wide bandgap of 3.0 to 3.2 eV, which is disadvantageous in that it can catalyze only under ultraviolet irradiation. In order to overcome this problem, various techniques such as doping, introduction of a visible light sensitive agent, and hetero semiconductor junction have been studied in order to utilize light in a visible region.

The visible light sensitizer is a dye sensitization agent using a dye capable of absorbing visible light and a ligand-metal charge transfer agent capable of absorbing light in a visible light region, (ligand-to-metal charge transfer (LMCT)). In the case of dye sensitization, it is not necessary to bond with the semiconductor surface, but in the case of sensitization due to the ligand-metal charge transfer, it is essential that the organic matter and the semiconductor are covalently bonded.

Visible light sensitizers have been developed on the basis of organic dyes, which are usually based on transition metals. However, since they require rare metals, they are less cost-competitive and are exposed to secondary environmental problems caused by metal elution. Therefore, introduction of macromolecules and organic molecules capable of absorbing visible light without a central metal has been suggested as a solution, but there is a problem in the complicated synthesis method of multistage and easy accessibility of the derived material.

In the case of dye sensitization, the efficiency is good but the cost is high and the long-term stability of the dye is not good. In the case of the ligand-metal charge transfer, the ligand is very cheap and the applicable material is unlimited. There is a problem that it is low.

It is an object of the present invention to provide a low cost photocatalytic composite in which a visible light sensitive layer on a semiconductor photocatalyst includes a catechol polymer and is active in ultraviolet and visible light regions.

Another object of the present invention is to provide a method for removing contaminants by using the photocatalytic composite under light irradiation in water.

Another object of the present invention is to provide a method for producing hydrogen peroxide which generates hydrogen peroxide using the photocatalytic composite under light irradiation in water.

Another object of the present invention is to provide a method of manufacturing the photocatalytic composite.

According to an aspect of the present invention, there is provided a semiconductor photocatalyst; And a visible light-sensitive layer on the semiconductor photocatalyst.

The visible light-sensitive material layer may include a catechol-based polymer.

The catechol-based polymer may include a polymer synthesized by autopolymerizing any one selected from a compound represented by the following structural formula 1 and a salt thereof.

[Structural formula 1]

In the above formula 1,

R is a hydrogen atom or a hydroxy group,

A is a single bond or a double bond,

X is an amino group or a carboxy group,

Y may be a hydrogen atom or a nitro group.

Wherein the catechol monomers may include at least one member selected from the group consisting of dopamine, norepinephrine, caffeic acid dinopamine, epinephrine, dihydroxyphenylalanine (L-DOPA), dihydroxyphenylacetic acid and dihydroxymandelic acid have.

The semiconductor photocatalyst may include at least one selected from titanium dioxide, tungsten trioxide, zinc oxide, and iron oxide.

The visible light-sensitive layer may have a thickness of 0.5 to 2.5 nm.

According to another aspect of the present invention, there is provided a pollutant removing method for irradiating light in water and removing contaminants using the photocatalytic composite.

The light irradiation can be performed by visible light.

The contaminants may be heavy metal ions.

The heavy metal ions are reduced by reducing any one selected from hexavalent chromium (Cr (VI)), trivalent arsenic (As (III)), monovalent silver (Ag (I)) and hexavalent selenium (Se Or oxidize.

The contaminant may be an organic compound.

May be one of the organic compound decomposition of carbon tetrachloride (CCl₄), dichloroacetic acid (CHCH ₂ COOH), 4- chlorophenol and 2,4-dichlorophenoxy any one selected from acetic acid.

According to another aspect of the present invention, there is provided a process for producing hydrogen peroxide which irradiates light in water and generates hydrogen peroxide using the photocatalytic composite as a photocatalyst.

The light irradiation can be performed by visible light.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: (a) preparing a mixture by mixing a semiconductor photocatalyst with any one selected from a catechol monomolecular material and a salt thereof; And (b) stirring the mixture to self-polymerize the catechol monomers on the semiconductor photocatalyst, thereby producing a photocatalytic composite in which the catechol polymer is coated on the semiconductor photocatalyst. do.

The content of the semiconductor photocatalyst may be 100 to 20,000, preferably 500 to 10,000, more preferably 1,000 to 5,000 parts by weight based on 100 parts by weight of the catechol monomers.

The catechol monomolecule may be represented by the following structural formula (1).

[Structural formula 1]

In the above formula 1,

R is a hydrogen atom or a hydroxy group,

A is a single bond or a double bond,

X is an amino group or a carboxy group,

Y may be a hydrogen atom or a nitro group.

Wherein the catechol monomers may include at least one member selected from the group consisting of dopamine, norepinephrine, caffeic acid dinopamine, epinephrine, dihydroxyphenylalanine (L-DOPA), dihydroxyphenylacetic acid and dihydroxymandelic acid have.

The photocatalytic composite of the present invention can provide a low-cost photocatalytic composite in which the visible light-sensitive layer on the semiconductor photocatalyst includes the catechol-based polymer and has activity in the ultraviolet and visible regions.

Further, it is possible to provide a method for removing contaminants by using the photocatalytic composite under light irradiation in water.

Further, it is possible to provide a method for producing hydrogen peroxide which generates hydrogen peroxide using the photocatalytic composite under light irradiation in water.

In addition, a method for producing the photocatalytic composite can be provided.

These drawings are for the purpose of describing an exemplary embodiment of the present invention, and therefore the technical idea of the present invention should not be construed as being limited to the accompanying drawings.
Fig. 1 shows ultraviolet-visible light scattering reflection spectra (DR-UVS) of the photocatalytic composites prepared in Examples 1 to 4.
Fig. 2 shows the attenuation total-Fourier transform infrared spectroscopy (ATR-FTIR) spectra of the photocatalytic composites prepared in Examples 1 to 4.
FIG. 3 shows the attenuation total-Fourier transform infrared spectroscopy of the catechol molecule, TiO _2, and the photocatalytic composite according to Examples 1 to 4 of the present invention.
4 is a high-resolution transmission electron microscope (HR-TEM) photograph and electron energy loss spectroscopy (EELS) mapping image of the photocatalytic composite according to Example 1 and TiO ₂ .
5 is a high-resolution transmission electron micrograph and an EELS mapping image of the photocatalytic composite according to Examples 2 to 4.
6 shows reduction amounts of Cr (VI) according to the photoreduction reactions of Examples 1-1 to 1-4.
7 shows the amounts of Cl ions generated according to the light reduction reaction examples 2-1 to 2-4.
8 shows the amount of As (V) produced according to the photoreducation reaction examples 3-1 to 3-4.
9 shows the amount of hydrogen peroxide generated according to the photoreducation reaction examples 4-1 to 4-4.
Figure 10 shows the Stern-Volmer plots of polydopamine and polyneopepneprin of the present invention.
Fig. 11 shows photocurrent accumulated over time in the photocatalytic composite according to Examples 1 to 4. Fig.
12 shows electrochemical impedance spectroscopic nyquist plots of the photocatalytic composites according to Examples 1 to 4.
13 shows the incident photon-to-current efficiencies (IPCE) spectra of the photocatalytic composites according to Examples 1 to 4. FIG.
14 shows the photoluminescence spectrum of the catechol polymer solution of the present invention and TiO ₂ added thereto.
Fig. 15 shows a comparison of the results of the photoreaction reduction examples 1 to 4 of the photocatalytic composite according to Example 1 and Comparative Example 1. Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description does not limit the present invention to specific embodiments. In the following description of the present invention, detailed description of related arts will be omitted if it is determined that the gist of the present invention may be blurred .

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises ", or" having ", and the like, specify that the presence of stated features, integers, steps, operations, elements, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or combinations thereof.

Furthermore, terms including an ordinal number such as first, second, etc. to be used below can be used to describe various elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component

Also, when an element is referred to as being "formed" or "laminated" on another element, it may be directly attached or laminated to the front surface or one surface of the other element, It will be appreciated that other components may be present in the < / RTI >

Hereinafter, the photocatalytic composite of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

The photocatalytic composite of the present invention can be used as a semiconductor photocatalyst; And a visible light-sensitive layer on the semiconductor photocatalyst.

The visible light-sensitive material layer may include a catechol-based polymer.

The catechol-based polymer may include a polymer synthesized by autopolymerizing any one of the compound represented by the following structural formula 1 and its salt.

[Structural formula 1]

In the above formula 1,

R is a hydrogen atom or a hydroxy group,

A is a single bond or a double bond,

X is an amino group or a carboxy group,

Y may be a hydrogen atom or a nitro group.

Wherein the catechol-based polymer is selected from the group consisting of polypodamine, polyneophenephrine, polycaphenic acid, polynitrodopamine, polyepinphrine, polydihydroxyphenylalanine (polyL-DOPA), polydihydroxyphenylacetic acid and polydihydroxymandelic acid And the like, and preferably, it may be polydopamine, polyneopheneprin.

Podopamine, which mimics mussel-derived proteins, has been applied to a variety of coating methods with excellent adhesion. These catechol molecules can be polymerized by autopolymerization in a basic solution and can form mono- or bidentate bonds with titanium dioxide, including hydroxy groups, so that complexes can be formed in a simple one-step process.

Polydopamine and other catechol-based polymers have advantages in that they are easy to synthesize, can be easily obtained at a low cost, and have a wide variety of choices.

The semiconductor photocatalyst may be titanium dioxide, tungsten trioxide, zinc oxide, iron oxide, or the like, preferably titanium dioxide.

The visible light-sensitive layer may have a thickness of 0.1 to 10 nm, preferably 0.2 to 5 nm, and more preferably 0.5 to 2.5 nm.

The present invention can provide a method for removing contaminants by irradiating light in water and removing contaminants using the photocatalytic composite.

The light irradiation can be performed by visible light.

The contaminants may be heavy metal ions.

The heavy metal ion may be one that reduces or oxidizes any one selected from hexavalent chromium, trivalent arsenic, monovalent silver, and hexavalent selenium.

The contaminant may be an organic compound.

The organic compound may decompose any one selected from carbon tetrachloride, dichloroacetic acid, 4-chlorophenol, and 2,4-dichlorophenoxyacetic acid.

The present invention can provide a method for producing hydrogen peroxide which irradiates light in water and generates hydrogen peroxide using the photocatalytic composite as a photocatalyst.

The light irradiation can be performed by visible light.

Hereinafter, a method for producing the semiconductor composite of the present invention will be described.

First, a mixture is prepared by mixing a semiconductor photocatalyst with any one selected from a catechol monomolecular or its salt (step a).

The content of the semiconductor photocatalyst may be 100 to 20,000 parts by weight, preferably 500 to 10,000 parts by weight, more preferably 1,000 to 5,000 parts by weight based on 100 parts by weight of the catechol monomers.

The catechol monomolecule may be represented by the following structural formula (1).

[Structural formula 1]

In the above formula 1,

R is a hydrogen atom or a hydroxy group,

A is a single bond or a double bond,

X is an amino group or a carboxy group,

Y may be a hydrogen atom or a nitro group.

Next, the mixture is stirred to prepare a photocatalytic composite in which the catechol monomers are self-polymerized on the semiconductor photocatalyst and the catechol polymer is coated on the semiconductor photocatalyst (step b).

As the above-mentioned catechol monomers, dopamine, norepinephrine, caffeic acid, nitrodopamine, epinephrine, dihydroxyphenylalanine (L-DOPA), dihydroxyphenylacetic acid and dihydroxy mandelic acid or a mixture thereof may be used . It is also possible to use salts of mono-molecules of catechol, such as dopamine, norepinephrine, caffeic acid, nitrodopamine, epinephrine, dihydroxyphenylalanine (L-DOPA), dihydroxyphenylacetic acid or dihydroxy mandelic acid, An example is dopamine hydrochloride (C ₈ H ₁₁ NO ₂ HCl).

The detailed description of the reactants and the products in the method of producing the semiconductor photocatalyst is omitted because it has been described in the semiconductor photocatalyst of the present invention.

[Example]

Hereinafter, preferred embodiments of the present invention will be described. However, this is for illustrative purposes only, and thus the scope of the present invention is not limited thereto.

As catechol monomers (CDs), dopamine is represented by DA, norepinephrine is represented by NE, caffeic acid is represented by CA, and nadrodopamine is represented by NDA. PADs as paternal dendritic polymers (pCDs), pNE as polynorphin, pNE as polynuclear epinephrine, Caffeic acid was labeled with pCA and polynitrodopamine was labeled with pNDA.

In Examples 1, 2, 3, and a photocatalyst composite of the four respective pDA-TiO _2, pNE-TiO _{2, and} pCA-TiO _2, pNDA-TiO indicated by _2, and a photocatalyst composite of the Comparative Example 1 DA-TiO ₂ Respectively.

Table 1 shows the chemical structure and properties of DA, NE, CA and NDA.

Name Molecular Formula / weight Structure pKa ^a Dopamine
(DA) C ₈ H ₁₁ NO ₂ / 153.18

9.05 Norepinephrine
(NE) C ₈ H ₁₁ NO ₃ / 169.18

8.58 Caffeic acid
(CA) C ₉ H ₈ O ₄ / 180.16

8.9 Nitrodopamine
(NDA) C ₈ H ₁₀ N ₂ O ₄ / 198.18

6.31

Example 1: Preparation of photocatalytic composite (pDA-TiO ₂ )

A mixed solution was prepared by mixing 10 mM (pH 8.5) of Tris buffer solution at a concentration of 0.05 g / L of dopamine hydrochloride and 1 g / L of TiO ₂ . The mixture was sonicated for 1 hour to disperse and then stirred at room temperature for 12 hours. The mixture was filtered with a vacuum pump, and the powder washed with deionized water was dried to prepare a photocatalytic composite in which dopamine self-polymerized polypodamine was coated on the surface of TiO ₂ .

Example 2: Preparation of photocatalytic composite (pNE-TiO ₂ )

(-) - norepinephrine was coated on the surface of TiO _{2 in the} same manner as in Example 1, except that (-) - norepinephrine was used instead of dopamine hydrochloride.

Example 3: Preparation of photocatalytic composite (pCA-TiO ₂ )

A photocatalytic composite was prepared in the same manner as in Example 1, except that caffeic acid was used in place of dopamine hydrochloride, and the polycapheic acid, which was self-polymerized with caffeic acid, was coated on the surface of TiO ₂ .

Example 4: Preparation of photocatalytic composite (pNDA-TiO ₂ )

A photocatalytic composite was prepared in the same manner as in Example 1, except that nitrophenyldopamine was used instead of dopamine hydrochloride, in which nitronododamine was self-polymerized and polyditrodopamine was coated on the surface of TiO ₂ .

Comparative Example 1: Production of photocatalytic composite (DA-TiO ₂ )

A photocatalyst composite coated with dopamine on the surface of TiO ₂ was prepared in the same manner as in Example 1 except that the pH of the solution was changed to 3 instead of 8.5 in order to prevent the dopamine from being polymerized into polypodamine.

Photoreduction Reaction Example 1: Cr (III) reduction of Cr (VI) by photoreduction reaction

Photoreduction Reaction Example 1-1: Cr (III) reduction of Cr (VI) by photoreduction reaction of the photocatalytic composite according to Example 1

A 30 mL aqueous solution containing 200 mu M Cr (VI) and 0.5 g / L of the photocatalytic composite according to Example 1 was placed in a Pyrex reactor and purged with argon gas for 30 minutes. The pH was adjusted using HClO ₄ or NaOH under the initial condition of pH 3 and the light was filtered through a IR filter and cutoff filter using a 300-W Xe arc lamp (Oriel) ? 440 nm) and irradiated to the reactor.

The concentration of Cr (VI) was measured by colorimetric method using DPC reagent. The change in color during the experiment was observed using a spectrophotometer (UV / visible spectrophotometer (Libra S22, Biochrom)) at 540 nm (ε = 4 × 104 Lmol-1 cm-1)

Photoreduction Reaction Example 1-2: Cr (III) reduction of Cr (VI) by the photoreduction reaction of the photocatalytic composite according to Example 2

The photoreduction reaction was carried out in the same manner as in Example 1-1, except that the photocatalytic composite according to Example 2 was used instead of the photocatalytic composite according to Example 1.

Photoreduction Reaction Examples 1-3: Cr (III) reduction of Cr (VI) by the photoreduction reaction of the photocatalytic composite according to Example 3

The photoreduction reaction was carried out in the same manner as in Example 1-1, except that the photocatalytic composite according to Example 3 was used instead of the photocatalytic composite according to Example 1.

Photoreduction Reaction Examples 1-4: Cr (III) reduction of Cr (VI) by the photoreduction reaction of the photocatalytic composite according to Example 4

The photoreduction reaction was carried out in the same manner as in Example 1-1, except that the photocatalytic composite according to Example 4 was used in place of the photocatalytic composite according to Example 1.

6 shows reduction amounts of Cr (VI) according to the photoreduction reactions of Examples 1-1 to 1-4.

Referring to FIG. 6, it can be seen that when the photocatalytic composite according to Examples 1 to 4 is used as compared with the case where only TiO ₂ is used, the amount of Cr (VI) decreases by the photoreduction reaction, 1> Example 2> Example 3> The procedure of Example 4 is shown, which indicates that the photocatalytic composite is related to the light absorption ability.

Photoreduction Reaction Example 2: CCl₄ degradation by photoreduction reaction

Photoreduction Reaction Example 2-1: CCl₄ degradation by photoreduction reaction of the photocatalytic composite according to Example 1

The production amount of Cl ions produced by the CCl₄ sensibility of the photocatalytic composite according to Example 1 was such that charge separation was possible using the photocatalytic composite according to Example 1 in which 10 mM of CCl₄ and 1 wt% of platinum were carried in advance. If the catalyst does not contain platinum, chloride is not produced. Also, the photoreducation reaction was carried out in the same manner as in Example 1 except that purging with argon gas was continued during the reaction and the concentration was measured by ion chromatography.

Photoreduction Reaction Example 2-2: CCl₄ degradation by photoreduction reaction of the photocatalytic composite according to Example 2

The photoreduction reaction was carried out in the same manner as in Example 2-1 except that the photocatalytic composite according to Example 2 was used in place of the photocatalytic composite according to Example 1.

Photoreduction Reaction Example 2-3: CCl₄ degradation by photoreduction reaction of the photocatalytic composite according to Example 3

The photoreduction reaction was carried out in the same manner as in Example 2-1 except that the photocatalytic composite according to Example 3 was used instead of the photocatalytic composite according to Example 1.

Photoreducation reaction Example 2-4: CCl₄ degradation by photoreduction reaction of the photocatalytic composite according to Example 4

The photoreducation reaction was carried out in the same manner as in Example 2-1 except that the photocatalytic composite according to Example 4 was used instead of the photocatalytic composite according to Example 1.

7 shows the amounts of Cl ions produced according to the light reduction reaction examples 2-1 to 2-4.

Referring to FIG. 7, the photoreduction reaction of the photocatalytic composite according to Examples 1 to 4, as in the photoreducation example 1, increased the production amount of Cl ions. In particular, the photocatalytic complexes of Examples 1 and 2 exhibited high efficiency .

Photo-reduction reaction Example 3: As (V) oxidation of As (III) by photo-reduction reaction

Photo-reduction reaction Example 3-1: As (V) oxidation of As (III) by photoreduction reaction of the photocatalytic composite according to Example 1

As (V) produced by As (III) oxidation of the photocatalytic composite according to Example 1 was measured by As (III) 100 μM and a pH of 9 and a molybdenum blue coloring method at 870 nm (ε = 19,550 L mol -1 cm < -1 >) was measured in the same manner as in Example 1, except that the concentration was measured.

Photoreduction Reaction Example 3-2: As (V) oxidation of As (III) by photoreduction reaction of the photocatalytic composite according to Example 2

The photoreduction reaction was carried out in the same manner as in Example 3-1 except that the photocatalytic composite according to Example 2 was used instead of the photocatalytic composite according to Example 1.

Photo-reduction reaction Example 3-3: As (V) oxidation of As (III) by photo-reduction reaction of the photocatalytic composite according to Example 3

The photoreduction reaction was carried out in the same manner as in Example 3-1 except that the photocatalytic composite according to Example 3 was used instead of the photocatalytic composite according to Example 1.

Photo-reduction reaction Example 3-4: As (V) oxidation of As (III) by photo-reduction reaction of the photocatalytic composite according to Example 4

The photoreduction reaction was carried out in the same manner as in Example 3-1 except that the photocatalytic composite according to Example 4 was used instead of the photocatalytic composite according to Example 1.

8 shows the As (V) production yields produced by the light reduction reaction examples 3-1 to 3-4.

Referring to FIG. 8, the photoreduction reaction of the photocatalytic composite increases the production amount of As (V) by the photoreduction reaction as in the photoreduction reaction of Example 1. In particular, the photocatalytic complex according to Examples 1 and 2 shows high efficiency .

Photoreduction Reaction Example 4: Production of hydrogen peroxide by photoreduction reaction

Photoreduction Reaction Example 4-1: Production of hydrogen peroxide by photoreduction reaction of the photocatalytic composite according to Example 1

The hydrogen peroxide production of the photocatalytic composite according to Example 1 was measured by measuring the concentration of the hydrogen peroxide by absorbance at 551 nm (ε = 21,000 L mol-1 cm-1) by the DPD coloring method so as to equilibrate with air with stirring for 30 minutes before the reaction The photoreducation reaction was carried out in the same manner as in Example 1.

Photoreduction Reaction Example 4-2: Production of hydrogen peroxide by photoreduction reaction of the photocatalytic composite according to Example 2

The photoreduction reaction was carried out in the same manner as in Example 4-1 except that the photocatalytic composite according to Example 2 was used instead of the photocatalytic composite according to Example 1.

Photoreduction Reaction Example 4-3: Production of hydrogen peroxide by photoreduction reaction of the photocatalytic composite according to Example 3

The photoreduction reaction was carried out in the same manner as in Example 4-1 except that the photocatalytic composite according to Example 3 was used instead of the photocatalytic composite according to Example 1.

Photoreduction Reaction Example 4-4: Production of hydrogen peroxide by photoreduction reaction of the photocatalytic composite according to Example 4

The photoreduction reaction was carried out in the same manner as in Example 4-1 except that the photocatalytic composite according to Example 4 was used instead of the photocatalytic composite according to Example 1.

Fig. 9 shows the hydrogen peroxide production amounts according to the photoreduction reactions Examples 4-1 to 4-4.

Referring to FIG. 9, it is hardly possible to utilize visible light when only TiO ₂ is used. However, the photocatalytic composite produced a considerable amount of hydrogen peroxide without the aid of electron carriers. Further, the photocatalytic composite according to Examples 1 and 2 The amount of hydrogen peroxide produced by the photocatalytic composite is twice as much as that of the photocatalytic composite according to Example 3 and Example 4, indicating that the polymer dye sensitizer is more efficient than the LMCT complex or the dimer dye sensitizer.

[Test Example]

Test Example 1: Absorption and Photoluminescence Spectrum Analysis of Photocatalytic Composite

Fig. 1 shows ultraviolet-visible light scattering reflection spectra of the photocatalytic composites according to Examples 1 to 4. Fig.

Fig. 2 shows the attenuation total-Fourier transform infrared spectroscopy (ATR-FTIR) spectra of the photocatalytic composites prepared in Examples 1 to 4.

Table 2 shows the functional groups of DA, NE, CA and NDA.

Referring to FIG. 1, it can be seen that when using TiO ₂ alone, visible light having a wavelength longer than about 400 nm can not be absorbed, whereas the photocatalytic composite prepared according to Examples 1 to 4 absorbs visible light of about 800 nm. And functions as a visible light-sensitive agent.

Referring to FIG. 2 and Table 2, when the transmittance according to the wavenumber is considered, it can be confirmed that the functional group of the catechol-based polymer is bonded to the surface of TiO ₂ .

Dopamine Norepinephrine Cafe Iksan Nitrodopamine IR Band
(cm ^-One ) Functional group IR Band
(cm ^-One ) Functional group IR Band
(cm ^-One ) Functional group IR Band
(cm ^-One ) Functional group 1205 C-N 1226 C-H in-plane bending 1215 C-H in-plane bending 1249 C-NH ₂ sym. stretching 1260 C-NH ₂ sym. stretching 1254 C-NH ₂ sym. stretching 1273 C-OH stretching 1282 C-O stretching 1284 C-O stretching 1272 C-O stretching 1296 OH in-plane bending 1312 C-NH ₂ asym. Stretching 1319 C-NH ₂ asym. Stretching 1304 C-NH ₂ asym. Stretching 1326 C-OH stretching 1338 Nitro (NO ₂ ) 1342 C-NH ₂ asym. stretching 1335 C-NH ₂ asym. Stretching 1352 C-H rocking 1376 Nitro (NO ₂ ) 1393 C-O-H in plane bending 1358 OH bending 1374 C-H stretching 1412 Aromatic C-C stretching 1469 aromatic C-C stretching 1420 Aromatic C-C stretching 1446 Aromatic C-C stretching (in-ring) 1435 Aromatic C-C stretching 1496 aromatic C-C stretching 1446 Aromatic C-C stretching 1524 Aromatic C-C stretching (in-ring) 1493 Aromatic C-C stretching 1519 N-H scissoring 1487 Aromatic C-C stretching 1597 Aromatic C-C stretching (in-ring) 1512 Nitro (NO ₂ ) 1581 Amine stretching 1543 Aromatic C-C stretching (in-ring) 1616 COOH 1539 Aromatic C-C stretching (in-ring) 1601 C = C resonance 1593 N-H bending (primary amine) 1640 -C = C-stretching, C = O stretching 1599 N-H bending (primary amine) 1616 Primary amine bending 1630 N-H bending (primary amine) 1624 N-H bending (primary amine)

Test Example 2: High resolution transmission electron microscope (HR-TEM) and electron energy loss spectrometry (EELS) analysis

4 Examples 1 and TiO ₂ HR-TEM image in the case of using only (Example 1 ab, TiO ₂ is fg) and an electron energy loss spectroscopy (electron energy loss spectroscopy) mapping image (Example 1 ce, TiO ₂ represents hj).

5 is a graph showing an HR-TEM image (ab in Example 2, fg in Example 3, kl in Example 4) and an EELS mapping image (Ce in Example 2 and Example 3 in Example 3) of the photocatalytic composite according to Examples 2 to 4, Hj, and Example 4 is mo).

Referring to FIGS. 4 and 5, the photocatalytic composite according to Examples 1 to 4 can observe an amorphous carbon layer which is not observed when only TiO ₂ is used. According to the EELS mapping image, only carbon and trace nitrogen existing in the lattice when only TiO ₂ is used is observed, but the photocatalytic composite according to Examples 1 to 4 can confirm carbon and nitrogen on the surface of TiO ₂ .

Test Example 3: Photoelectrochemical measurement

Figure 10 shows a stern-bolmer plot of the polydopamine and polyneopepneprin of the present invention.

11 shows photocurrent accumulation amounts of the photocatalytic composite according to Examples 1 to 4 with time.

FIG. 12 is a graph showing an EIS Nyquist plot of the photocatalytic composite according to Examples 1 to 4. FIG.

13 shows the incident photon-to-current efficiencies (IPCE) spectra of the photocatalytic composites according to Examples 1 to 4. FIG.

14 shows the photoluminescence spectra of the catechol polymer solution of the present invention and TiO ₂ added thereto.

Specifically, photocurrent and electrochemical impedance (EIS) measurements were measured by three electrode systems connected to a potentiostat (Gamry, Reference 600). Photocatalytic complex coated electrode, coiled Pt wire and Ag / AgCl were used as working electrode, counter electrode, and standard electrode, respectively. The LiClO4 electrolyte solution was purged with Ar gas under visible light irradiation (?> 420 nm), and the Pt electrode was biased at a potential of +0.5 V (vs. Ag / AgCl). The TiO ₂ / FTO (fluorine-doped SnO ₂ , Pilkington) electrode was prepared by a known doctor-blade method. The surface complex of the catechol polymer was prepared by immersing the electrode in the solution.

IPCE measurements were carried out in the same manner as photocurrent and electrochemical impedance measurements except for the wavelength of the light being irradiated.

Referring to FIG. 10, the Stern-Bolmer diagram of the photocatalytic composite according to Example 1 and Example 2 shows a positive deviation, indicating that the photocatalytic composite chemically bonds with TiO ₂ to form a charge-transporting complex.

Referring to FIG. 14, in the case of polycapneic acid, the presence of TiO ₂ greatly increases the photoluminescence intensity, which indicates that the LMCT complex capable of absorbing visible light is formed. On the other hand, the presence of polyditrodopamine in the presence of TiO ₂ slightly increases the photoluminescence intensity, indicating that the association of dopamine with TiO ₂ by polynucleotides through electrostatic interactions delays the quenching of dopamine in polynitrides .

Referring to FIG. 11, it can be seen that the photocurrent amount of the photocatalytic composite according to Example 1 or 2 is higher, indicating that the polymer dye-sensitizer shows high efficiency as a visible light sensitizer.

Referring to FIG. 12, the charge transfer of the photocatalytic composite according to Examples 1 to 4 is easier than using only TiO ₂ , and as the arc of the EIS Nyquist line becomes smaller, It can be confirmed from the fact that the photocatalytic composite according to Example 1 exhibits the smallest arc.

Referring to FIG. 13, even if the absorption range of the photocatalytic composite reaches 800 nm, the IPCE spectrum is limited to 450-500 nm because the visible light in the long wavelength region is weak enough to produce a sufficient current. However, the photocatalytic composite according to Examples 1 and 2 exhibits a larger IPCE value in the visible light region, indicating that the polymer dye sensitizer is more effective as a visible light sensitizer.

Test Example 4: Comparison of optical activity between a polymer dye-sensitizer and a monomolecular LMCT complex

15 compares the results of the photoreducation reactions according to Examples 1 to 4 of the photoreducation reaction of the photocatalytic composite according to Example 1 and Comparative Example 1. Fig.

Referring to FIG. 15, it can be seen from all the test results that the activity of the photocatalytic composite according to Example 1 is high, indicating excellent activity of the catechol-based polymer of the present invention.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (18)

Semiconductor photocatalyst; And
And a visible light-sensitive layer on the semiconductor photocatalyst,
Wherein the visible light-sensitive agent layer is polyneophenephrine. delete delete delete The method according to claim 1,
Wherein the semiconductor photocatalyst comprises at least one selected from titanium dioxide, tungsten trioxide, zinc oxide and iron oxide. The method according to claim 1,
Wherein the visible light-sensitive layer has a thickness of 0.1 to 10 nm. A photocatalytic composite according to claim 1, wherein the photocatalytic composite is irradiated with light in water to remove the contaminant. 8. The method of claim 7,
Wherein the light irradiation is performed by visible light. 8. The method of claim 7,
Wherein the contaminant is a heavy metal ion. 10. The method of claim 9,
Wherein the heavy metal ion is reduced or oxidized in any one of hexavalent chromium, trivalent arsenic, monovalent silver, and hexavalent selenium. 8. The method of claim 7,
Wherein the pollutant is an organic compound. 12. The method of claim 11,
Wherein the organic compound decomposes any one selected from carbon tetrachloride, dichloroacetic acid, 4-chlorophenol, and 2,4-dichlorophenoxyacetic acid. A method for producing hydrogen peroxide, wherein light irradiation is performed in water, and hydrogen peroxide is produced by using the photocatalytic composite according to claim 1 as a photocatalyst. 14. The method of claim 13,
Wherein the light irradiation is performed by visible light. (a) preparing a mixture by mixing a semiconductor photocatalyst with any one selected from a catechol monomolecular material and a salt thereof; And
and (b) stirring the mixture to prepare a photocatalytic composite in which the catechol monomers self-polymerize on the semiconductor photocatalyst and the catechol polymer is coated on the semiconductor photocatalyst,
Wherein the catechol monomolecule is norepinephrine. 16. The method of claim 15,
Wherein the content of the semiconductor photocatalyst is 100 to 20,000 with respect to 100 parts by weight of the catechol monomers. delete delete

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