WO2021049811A1

WO2021049811A1 - Titanium dioxide composite, method for preparing same, and photocatalyst comprising same

Info

Publication number: WO2021049811A1
Application number: PCT/KR2020/011794
Authority: WO
Inventors: 이효영; 티킴 챠우 느구엔
Original assignee: 성균관대학교산학협력단; 기초과학연구원
Priority date: 2019-09-09
Filing date: 2020-09-02
Publication date: 2021-03-18
Also published as: KR20210030015A; KR102257999B1

Abstract

The present application relates to a titanium dioxide composite comprising: reduced titanium dioxide (TiO2) comprising an anatase phase and a rutile phase, wherein any one of the anatase phase and the rutile phase is reduced; and a metal oxide bound to the reduced titanium dioxide.

Description

Titanium dioxide composite, manufacturing method thereof, and photocatalyst comprising same

The present application relates to a titanium dioxide composite, a method of manufacturing the same, and a photocatalyst comprising the same.

The emission of organic solvents used in various industrial fields causes many problems in the atmosphere, water quality, soil, and the ocean at the same time as industrial development. In particular, organic compounds classified as volatile organic substances exist in the atmosphere in various forms, which is a serious environmental problem. Is causing. As such environmental issues emerged as humanity's greatest priority, in the late 1980s, in advanced countries including the United States and Japan, there are active movements to treat these organic materials in an environmentally friendly manner using semiconductor metal oxides as photocatalysts. .

Among these studies, the _{field of photocatalyst using titanium dioxide (TiO 2} ) is attracting attention recently, and its performance is also environmentally friendly and economical compared to the existing environmental treatment methods such as activated carbon adsorption, chemical treatment, ozone decomposition, and incineration. Due to its outstanding advantages, many studies are currently underway.

In order to maximize the absorption of TiO ₂ under sunlight, research is underway to change the composition of _{TiO 2} by doping with metals, inorganic components, and Ti ^{3+ species.} Through doping, _{the light absorption property of TiO 2} is improved, but nitrogen-doped TiO ₂ only reacts to solar irradiation, and absorption in visible and infrared light is still insufficient.

On the other hand, platinum has the best catalytic activity characteristics and has been applied in various ways in the catalytic field, but it is a rare metal and is expensive, causing difficulties in inexpensive operation of the catalyst. Therefore, efforts such as reducing the amount of platinum or developing an alternative catalyst are required.

The paper behind the present application (Zhang, Kan, et al. "An Order/Disorder/Water Junction System for Highly Efficient Co-Catalyst-Free Photocatalytic Hydrogen Generation." Energy & Environmental Science, vol. 9, no. 2, 2016 , pp. 499-503.) is a paper on the method of generating hydrogen with high efficiency through photocatalyst in orderly, disorderly, and water-bonded systems. The paper discloses that P-25, which contains disordered and orderly phases by adding Li-EDA to P-25 TiO ₂ _{, can have high electron-hole separation efficiency and hydrogen generation efficiency, but the TiO 2} It does not disclose a method for further improving the efficiency.

The present application is to solve the problems of the prior art described above, and an object thereof is to provide a titanium dioxide composite.

In addition, an object of the present invention is to provide a method for producing the titanium dioxide composite.

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

However, the technical problem to be achieved by the embodiments of the present application is not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the first aspect of the present application includes an anatase phase and a rutile phase, and any one of the anatase phase and the rutile phase is reduced. Reduced titanium dioxide (TiO ₂ ) , And it provides a titanium dioxide complex comprising a metal oxide combined with the reduced titanium dioxide.

According to the exemplary embodiment of the present disclosure, the titanium dioxide composite may further include the reduced titanium dioxide or metal nanoparticles formed on the metal oxide, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, based on 100 parts by weight of the titanium dioxide composite, the metal nanoparticle may be less than 10 parts by weight, and the metal oxide may be 30 parts by weight to 70 parts by weight, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal nanoparticles may supply electrons onto the reduced titanium dioxide, but are not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal nanoparticle may have a diameter of 1 nm to 10 nm, but is not limited thereto.

According to one embodiment of the present application, the metal nanoparticles are Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe , And a metal element selected from the group consisting of combinations thereof, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, a reduction reaction may occur in the reduced titanium dioxide, and an oxidation reaction may occur in the metal oxide, but the present invention is not limited thereto.

According to the exemplary embodiment of the present disclosure, a conduction band of the metal oxide may be greater than a valence band of the reduced titanium dioxide and may be smaller than a conduction band of the reduced titanium dioxide, but is limited thereto. It is not.

According to the exemplary embodiment of the present disclosure, a band gap of the reduced titanium dioxide may be larger than a band gap of the metal oxide, but is not limited thereto.

According to one embodiment of the present application, the metal oxide is W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ti, It may include a metal element selected from the group consisting of Ca, Nb, K, Na, Li, and combinations thereof, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the reduced titanium dioxide may exhibit blue color, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the reduced titanium dioxide particles and the metal oxide particles may each independently have a diameter of 10 nm to 100 nm, but are not limited thereto.

According to the exemplary embodiment of the present disclosure, the diameter of the reduced titanium dioxide particles may be smaller than the diameter of the metal oxide particles, but is not limited thereto.

In addition, the second aspect of the present application is a step of forming reduced titanium dioxide by selectively reducing any one of the anatase phase and the rutile phase by mixing _{titanium dioxide (TiO 2) including an anatase phase and a rutile phase with a reducing agent} , And dispersing the reduced titanium dioxide and metal oxide in a solvent and then irradiating light to prepare a titanium dioxide composite, it provides a method for producing a titanium dioxide composite.

According to the exemplary embodiment of the present disclosure, the step of preparing the titanium dioxide composite may further include adding a metal salt including metal nanoparticles to the solvent, but is not limited thereto.

According to one embodiment of the present application, the metal salt is Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, And a metal element selected from the group consisting of combinations thereof, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the reducing agent may include a metal and a basic organic solvent, but is not limited thereto.

According to one embodiment of the present application, the metal may include a metal selected from the group consisting of Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, and combinations thereof. However, it is not limited thereto.

According to one embodiment of the present application, the basic organic solvent is an alkyl amine, a dialkyl amine, a cyclic alkyl amine, a dicyclic alkyl amine, and their It may include a material selected from the group consisting of combinations, but is not limited thereto.

In addition, a third aspect of the present application provides a photocatalyst comprising the titanium dioxide composite according to the first aspect.

The above-described problem solving means are merely exemplary and should not be construed as limiting the present application. In addition to the above-described exemplary embodiments, additional embodiments may exist in the drawings and detailed description of the invention.

According to the solution to the above-described problem, the titanium dioxide composite according to the present application has a narrow band gap of 2.6 eV or less, and has high stability and charge carrier separation ability, so that it can be used in a nanostructured semiconductor.

In general, the process of reducing carbon dioxide _{tends to produce hydrogen, methane (CH 4} ), and carbon monoxide together. In this regard, the process of reducing carbon dioxide using the titanium dioxide composite according to the present application can obtain only carbon monoxide without by-products.

In addition, unlike conventional titanium dioxide materials whose catalytic activity is activated by ultraviolet rays, the titanium dioxide composite according to the present application includes metal oxides and/or metal nanoparticles, so that the catalytic activity is not only performed by ultraviolet rays, but also visible rays and/or infrared rays. Can be activated.

Specifically, since the conduction band of the metal oxide of the titanium dioxide composite is slightly larger than the valence band of the reduced titanium dioxide, the metal nanoparticles are supplied as the conduction band of the metal oxide. Electrons are transferred to the valence band of the reduced titanium dioxide, and the electrons are excited by ultraviolet rays, visible rays, and/or infrared rays to reduce a substance such as carbon dioxide.

In addition, the titanium dioxide composite according to the present application can repeatedly reduce the material over a long period of time.

In addition, the titanium dioxide composite according to the present application includes a metal oxide in which metal nanoparticles are formed and reduced titanium dioxide, so that fine dust, nitrogen oxide (NO _x ) contained in automobile exhaust gas and/or cigarette smoke, animal powder smell, acetate Organic contamination such as aldehyde, formaldehyde, methylmercaptan, methylene blue, acetic acid, organic solvents, paints and thinners, adhesives, dry cleaning fluids, adhesives, wood preservatives, cleaners and disinfectants, moth repellents, building materials and fixtures, pesticides, etc. Substance can be removed.

In addition, the titanium dioxide complex according to the present application is attached to the air purifier filter to remove pollutants in the air, and various fungi, bacteria, and bacteria can be removed.

However, the effect obtainable in the present application is not limited to the above-described effects, and other effects may exist.

1 is a schematic diagram of a titanium dioxide composite according to an embodiment of the present application.

2 is a diagram of a band structure of a titanium dioxide and titanium dioxide composite according to an embodiment of the present application.

3 is a flow chart showing a method of manufacturing a titanium dioxide composite according to an embodiment of the present application.

4 is a schematic diagram showing a method of manufacturing a titanium dioxide composite according to an embodiment of the present application.

5A and 5B are TEM images of a titanium dioxide composite according to an embodiment of the present application.

6 is an HADDF-STEM and EDS image of a titanium dioxide composite according to an embodiment of the present application.

7A is an XRD analysis of a material according to an example and a comparative example of the present application, b and c are an XPS analysis of a material according to a comparative example of the present application, and d to f are according to an example of the present application. The following material was analyzed by XPS.

8A and 8B are UV-Vis spectra of a material according to an embodiment and a comparative example of the present application, c is a Tauc plot of a material according to a comparative example of the present application, and d is an exemplary embodiment of the present application. The VB-XPS spectrum of the material according to Examples and Comparative Examples, e is a PL spectrum, and f is data on a photoresponse.

9A is a gas chromatography of a material according to an example and a comparative example of the present application, and b to d are graphs of CO generation over time.

10A and 10B are graphs of photocatalytic properties of materials according to Examples and Comparative Examples of the present application.

11 a and b are graphs of the PL spectrum and intensity of a material according to a comparative example of the present application, and c and d are graphs of a band structure of a material according to a comparative example of the present application.

12 is a graph showing the decomposition of cigarette smoke of the titanium dioxide composite according to an embodiment of the present application.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present application.

However, the present application may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description are omitted in order to clearly describe the present application, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the present specification, when a part is said to be "connected" with another part, this includes not only the case that it is "directly connected", but also the case that it is "electrically connected" with another element interposed therebetween. do.

Throughout the present specification, when a member is positioned "on", "upper", "upper", "under", "lower", and "lower" of another member, this means that a member is located on another member. This includes not only the case where they are in contact but also the case where another member exists between the two members.

In the entire specification of the present application, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

As used herein, the terms "about", "substantially" and the like are used in or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and to aid understanding of the present application. In order to avoid unreasonable use by unscrupulous infringers of the stated disclosures, either exact or absolute figures are used. In addition, throughout the specification of the present application, "step to" or "step of" does not mean "step for".

In the entire specification of the present application, the term "combination of these" included in the expression of the Makushi format refers to one or more mixtures or combinations selected from the group consisting of components described in the expression of the Makushi format, and the constituent elements It means to include one or more selected from the group consisting of.

Throughout this specification, the description of "A and/or B" means "A or B, or A and B".

Hereinafter, the titanium dioxide composite of the present application, a method of manufacturing the same, and a photocatalyst including the same will be described in detail with reference to embodiments and examples and the drawings. However, the present application is not limited to these embodiments and examples and drawings.

Titanium dioxide according to the present application is a material that can have various uses, such as a photovoltaic device, as well as a catalyst for a hydrogen generation reaction. Titanium dioxide existing in nature may largely include two phases of an anatase phase and/or a rutile phase, and physical properties may be changed by various reasons such as the ratio of the two phases. Typically, the band gap of the titanium dioxide is about 3.1 eV.

In this regard, titanium dioxide including the rutile phase and the anatase phase and in which neither the anatase phase nor the rutile phase is reduced may be expressed as P25.

The rutile phase according to the present application is also known as rutile, and titanium dioxide in nature mostly has a rutile phase. The rutile phase is superior to the anatase phase in weather resistance, hiding power, white luminance, and dielectric constant.

The anatase phase according to the present application has excellent photocatalytic activity for decomposing contaminants present in water or air, and abrasion resistance may be improved when the anatase-phase titanium dioxide is coated on another material.

When the titanium dioxide including the rutile phase and/or the anatase phase is irradiated with light, it can be used for various purposes such as photocatalyst, solar cell, organic material removal. However, when titanium dioxide in its natural state is simply used without any process, there is a disadvantage that it is difficult to commercialize it, such as having relatively low efficiency and reacting only to light of a specific wavelength.

In the prior art known by the inventors of the present invention, reduced titanium dioxide in which only at least one of the rutile phase and/or anatase phase of the titanium dioxide is reduced is disclosed. However, in the present application, the reduced titanium dioxide is used as the metal. By combining it with an oxide, it can have better physical properties and effects.

The reduced titanium dioxide according to the present application is obtained by reducing at least one of the rutile phase and the anatase phase, and the other refers to a material that is not reduced. For example, the reduced titanium dioxide may include a reduced rutile phase and an unreduced anatase phase, or may include a reduced anatase phase and an unreduced rutile phase, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the reduced rutile phase or anatase phase may have amorphousness, and the unreduced rutile phase or anatase phase may have crystallinity, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the reduced titanium dioxide may have the form of nanoparticles, but is not limited thereto. As will be described later, the reduced titanium dioxide particles may be combined with the metal oxide particles and the metal nanoparticles to form the titanium dioxide composite.

According to the exemplary embodiment of the present disclosure, the reduced phase _{may include a substituent selected from the group consisting of -OH group, -COOH group, -SO 3} group, and combinations thereof, but is not limited thereto.

Specifically, since the anatase phase exhibits a dark blue color when reduced, and the rutile phase becomes white when not reduced, the reduced titanium dioxide including the reduced anatase phase and the unreduced rutile phase may exhibit blue color. In addition, since the rutile phase has a dark blue color when reduced and the anatase phase is white when not reduced, the reduced titanium dioxide including the reduced rutile phase and the unreduced anatase phase may exhibit blue color.

In the following embodiments, examples, experimental examples, and drawings, the term BT may mean reduced titanium dioxide having a blue color.

The titanium dioxide composite according to the present application includes the reduced titanium dioxide and a metal oxide. In this regard, the metal oxide may exist in a bonded state surrounded by the reduced titanium dioxide, or may exist in a bonded state surrounded by the reduced titanium dioxide.

As will be described later, preferably, the reduced titanium dioxide particles may be surrounded by the metal oxide particles to form the titanium dioxide complex, but the present invention is not limited thereto.

Referring to FIG. 1, the metal nanoparticles are formed on the reduced titanium dioxide and/or the metal oxide, and the reduced titanium dioxide may exist in a state surrounding the metal oxide, but is not limited thereto. .

The electrons on the metal nanoparticles are vibrated by a localized surface plasmon resonance phenomenon, so that the electrons are transferred onto the valence band of the reduced titanium dioxide or the conduction band of the metal oxide. I can.

The local surface plasmon resonance phenomenon according to the present application is when light of a certain wavelength is irradiated onto the nanostructured surface of a metal having a size less than or equal to the certain wavelength, the surface of the metal and the dielectric, for example, the metal oxide or the reduced It refers to a phenomenon in which electrons vibrate at the boundary of titanium dioxide.

As will be described later, the metal nanoparticles have a diameter of 1 nm to 10 nm, and the wavelength of light irradiated to increase the catalytic activity of the titanium dioxide complex or the photocatalyst including the titanium dioxide complex is 200 nm to 1500 nm, A local surface plasmon resonance phenomenon occurs on the surface of the metal nanoparticles, and electrons may be transferred to the reduced titanium dioxide or the metal oxide.

According to the exemplary embodiment of the present disclosure, the reduced titanium dioxide may be combined with the metal oxide or doped with the metal nanoparticles, thereby further forming a trap site between the band gaps of the reduced titanium dioxide.

Specifically, when either the anatase phase or the rutile phase is reduced and either is not reduced, the difference in the band gap between the reduced phase and the non-reduced phase increases, and between the band gaps A new trap site is formed. In addition, when the reduced titanium dioxide is bonded to the metal oxide or is doped by the metal nanoparticles, a new trap site may be additionally formed between the band gaps, which is By improving the separation efficiency of electron-hole pairs, activation energy required for photo-excitation is lowered, so that light in the ultraviolet, visible, and/or infrared regions can be effectively absorbed.

According to the exemplary embodiment of the present disclosure, the metal oxide and the reduced titanium dioxide may be Z-scheme heterojunction, but is not limited thereto.

When different materials are electrically heterozygous, they can be divided into several types according to the size of the valence band and the conduction band of the two materials. For example, if the valence band of substance A is larger than that of substance B and the conduction band of substance A is smaller than that of substance B, the two substances are straddling heterojunction (type I). It may have been.

In addition, if the valence band of material A exists between the valence band and the conduction band of material B, and the conduction band of material A is larger than the conduction band of material B, it is a staggered heterojunction (type II). I can.

Z-scheme heterojunction according to the present application is a kind of staggered heterozygous, and can be confirmed in Fig. 11 to be described later, but in the staggered heterozygous titanium dioxide composite, the conduction band of the reduced titanium dioxide band), and electrons excited by light move to the conduction band of the metal oxide, and holes present on the valence band of the metal oxide become the valence band of the reduced titanium dioxide. It is to move.

However, the titanium dioxide complex according to the present application is a Z-scheme heterojunction, and electrons excited by light into the conduction band of the metal oxide may move to the valence band of the reduced titanium dioxide. The electrons transferred to the valence band of the reduced titanium dioxide are again excited by light as a conduction band of the reduced titanium dioxide, and the electrons can reduce carbon dioxide to carbon monoxide or remove organic substances.

As will be described later, the titanium dioxide complex may be used in _{a process of obtaining carbon monoxide, methane (CH 4} ), and hydrogen by reducing a material, and a process of removing organic materials contained in cigarette smoke and the like.

Preferably, the metal nanoparticles may be Ag, but are not limited thereto.

For example, with respect to 100 parts by weight of the titanium dioxide composite, as the weight part occupied by the metal nanoparticles increases, the frequency of the local surface plasmon resonance phenomenon increases, thereby increasing the catalytic activity of the titanium dioxide composite. However, based on 100 parts by weight of the titanium dioxide composite, when the metal nanoparticles are 10 parts by weight or more, the light irradiated onto the reduced titanium dioxide or the metal oxide may decrease, thereby lowering the catalytic activity of the titanium dioxide composite. have.

In addition, for example, based on 100 parts by weight of the titanium dioxide composite, the metal oxide is about 30 parts by weight to about 70 parts by weight, about 30 parts by weight to about 60 parts by weight, about 30 parts by weight to about 50 parts by weight, about 30 parts by weight to about 40 parts by weight, about 40 parts by weight to about 70 parts by weight, about 50 parts by weight to about 70 parts by weight, about 60 parts by weight to about 70 parts by weight, about 40 parts by weight to about 60 parts by weight, or It may be about 45 parts by weight to about 55 parts by weight, but is not limited thereto.

In addition, with respect to 100 parts by weight of the titanium dioxide composite, the ratio by weight of the reduced titanium dioxide and the metal oxide is 1: 9 to 9: 1, 2: 8 to 8: 2, 7: 3 to 3 : 7, 4: 6 to 6: 4, or may be 5: 5, but is not limited thereto.

Preferably, with respect to 100 parts by weight of the titanium dioxide composite, the metal nanoparticles are less than 2 parts by weight, and the ratio by weight of the reduced titanium dioxide and the metal oxide may be, for example, 1:1. , But is not limited thereto.

For example, when the ratio by weight of the reduced titanium dioxide and the metal oxide is greater than or less than 1:1, the ratio of the metal oxide on the titanium dioxide composite is insufficient or excessive, due to the local surface plasmon resonance phenomenon. It cannot act as a recombination center for generated or transferred electrons.

Referring to FIG. 2, it can be seen that the band gap of unreduced titanium dioxide is 3.10 eV, which is larger than the band gap of _{the reduced titanium dioxide and the metal oxide, for example WO 3.}

In addition, _{it can be seen that the conduction band of WO 3} is higher than the valence band of the reduced titanium dioxide and lower than the conduction band, and electrons excited by light are the reduced dioxide through the _{WO 3 phase according to the Z-scheme.} It moves to the valence band of titanium and can be excited again by light into an electron band. In addition, at the same time as the electron excitation process, the reduced titanium dioxide and the _{Ag nanoparticles formed on the WO 3} receive light to generate a local surface plasmon resonance phenomenon to generate electrons. _{The reduced titanium dioxide and electrons formed in the conductive band of WO 3} by the surface plasmon resonance phenomenon may reduce carbon dioxide to carbon monoxide in Ag nanoparticles.

As will be described later, the titanium dioxide complex includes an ordered phase (non-reduced phase) and an orderly phase (reduced phase), and the catalytic activity is activated when light is received even in a state impregnated in a solvent phase. The region where the redox process occurs can be efficiently separated. In addition, electrons transferred from the metal nanoparticles may have various uses, such as reduction of substances, removal of organic substances, generation of hydrogen, etc. without being easily bonded to holes on the metal oxide or the reduced titanium dioxide.

For example, the metal nanoparticles are about 1 nm to about 10 nm, about 1 nm to about 9 nm, about 1 nm to about 8 nm, about 1 nm to about 7 nm, about 1 nm to about 6 nm, about 1 nm to about 5 nm, about 1 nm to about 4 nm, about 1 nm to about 3 nm, about 1 nm to about 2 nm, about 2 nm to about 10 nm, about 3 nm to about 10 nm, about 4 nm To about 10 nm, about 5 nm to about 10 nm, about 6 nm to about 10 nm, about 7 nm to about 10 nm, about 8 nm to about 10 nm, about 9 nm to about 10 nm, about 2 nm to about 9 nm, about 3 nm to about 8 nm, about 4 nm to about 7 nm, or about 5 nm to about 6 nm, but is not limited thereto.

Preferably, the metal nanoparticles may be about 5 nm to about 8 nm, but are not limited thereto.

For example, the reduced titanium dioxide particles and the metal oxide particles are each independently about 10 nm to about 100 nm, about 20 nm to about 100 nm, about 30 nm to about 100 nm, about 40 nm to about 100 nm , About 50 nm to about 100 nm, about 60 nm to about 100 nm, about 70 nm to about 100 nm, about 80 nm to about 100 nm, about 90 nm to about 100 nm, about 10 nm to about 90 nm, about 10 nm to about 80 nm, about 10 nm to about 70 nm, about 10 nm to about 60 nm, about 10 nm to about 50 nm, about 10 nm to about 40 nm, about 10 nm to about 30 nm, about 10 nm To about 20 nm, about 20 nm to about 90 nm, about 20 nm to about 80 nm, about 20 nm to about 70 nm, about 20 nm to about 60 nm, about 20 nm to about 50 nm, about 20 nm to about 40 nm, about 20 nm to about 30 nm, about 30 nm to about 90 nm, about 30 nm to about 80 nm, about 30 nm to about 70 nm, about 30 nm to about 60 nm, about 30 nm to about 50 nm , About 30 nm to about 40 nm, about 40 nm to about 90 nm, about 40 nm to about 80 nm, about 40 nm to about 70 nm, about 40 nm to about 60 nm, about 40 nm to about 50 nm, about 50 nm to about 90 nm, about 50 nm to about 80 nm, about 50 nm to about 70 nm, about 50 nm to about 60 nm, about 60 nm to about 90 nm, about 60 nm to about 80 nm, about 60 nm To about 70 nm, about 70 nm to about 90 nm, about 70 nm to about 80 nm, or about 80 nm, but is not limited thereto.

Preferably, for example, the diameter of the reduced titanium dioxide particles may be about 20 nm to about 40 nm, and the diameter of the metal oxide particles may be about 50 nm to about 80 nm, but is not limited thereto.

In addition, the second aspect of the present application is a step of forming reduced titanium dioxide by selectively reducing any one of the anatase phase and the rutile phase by mixing _{titanium dioxide (TiO 2) including an anatase phase and a rutile phase with a reducing agent} , And dispersing the reduced titanium dioxide and metal oxide in a solvent and then irradiating light to prepare a titanium dioxide composite.

With respect to the method of manufacturing the titanium dioxide composite according to the second aspect of the present application, detailed descriptions of parts overlapping with the first aspect of the present application have been omitted, but even if the description is omitted, the content described in the first aspect of the present application is The same can be applied to the second aspect.

In order to prepare the titanium dioxide complex according to the present application, titanium dioxide (TiO ₂ ) including an anatase phase and a rutile phase is first mixed with a reducing agent to selectively reduce any one of the anatase phase and the rutile phase, thereby reducing titanium dioxide. To form (S100).

According to one embodiment of the present application, the reducing agent may include any one of sodium in ethlenediamine (Na-EDA), K-EDA, and Li-EDA, but is not limited thereto.

For example, when the reducing agent is Na-EDA or K-EDA, the reduced titanium dioxide may be a material in which the anatase phase is selectively reduced.

For example, when the reducing agent is Li-EDA, the reduced titanium dioxide may be a material in which the rutile phase is selectively reduced.

According to one embodiment of the present application, the reduction may be performed in a sealed and anhydrous state at room temperature, but is not limited thereto.

Accordingly, when the reduced titanium dioxide is manufactured through the method according to the present application, titanium dioxide can be reduced by a cheaper and simpler process compared to the conventional process of reducing titanium dioxide under high temperature and high pressure conditions.

Subsequently, the reduced titanium dioxide and metal oxide are dispersed in a solvent and then irradiated with light to prepare a titanium dioxide composite (S200).

According to the exemplary embodiment of the present application, the solvent may include a _{polar organic solvent consisting of methanol, a reducing agent including the basic organic solvent, H 2} O, ethanol, acetone, and combinations thereof, but is limited thereto. no.

The metal salt releases metal ions in the solvent, and the metal ions may be attached to the reduced titanium dioxide and/or the metal oxide in the form of nanoparticles.

According to one embodiment of the present application, the metal particles are Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, And a metal element selected from the group consisting of combinations thereof, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the wavelength of the irradiated light may be 300 nm to 400 nm, but is not limited thereto. Preferably, the wavelength of the irradiated light is about 365 nm.

With respect to the photocatalyst according to the third aspect of the present application, detailed descriptions of parts overlapping with the first and second aspects of the present application have been omitted, but contents described in the first and second aspects of the present application even if the description is omitted. Is equally applicable to the third aspect of the present application.

According to the exemplary embodiment of the present disclosure, the photocatalyst may be activated by receiving light in the solvent, but the catalytic activity is not limited thereto.

According to the exemplary embodiment of the present disclosure, the photocatalyst may be activated as a catalyst by light having a wavelength of 300 nm to 1500 nm, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the photocatalyst may be for generating hydrogen, reducing substances, or removing fine dust or organic pollutants in an aqueous solution, but is not limited thereto.

According to one embodiment of the present application, the titanium dioxide composite on the photocatalyst is combined with the ordered phase (non-reduced phase), the disordered phase (reduced phase), and water to form order/disorder/water junction (order/ disorder/water junction), but is not limited thereto.

Through the order/disorder/water bonding, the photocatalyst may have very high hydrogen generation efficiency without the presence of a cocatalyst.

The photocatalyst according to the present invention can be used for the removal of organic substances contained in the carbon monoxide production process, cigarette smoke, etc. by catalytic activity is activated by ultraviolet, visible light, and/or light in the infrared region. Specifically, the photocatalyst includes the titanium dioxide complex, and electrons produced from the metal nanoparticles formed on the metal oxide are transferred to the metal nanoparticles formed on the reduced titanium dioxide to reduce various substances, or It can be used for various purposes such as removal of fine dust and organic substances.

When conventional titanium dioxide or the reduced titanium dioxide is used in combination with a hydrogen generation catalyst such as Pt as a photocatalyst for hydrogen generation, it may have a hydrogen generation rate of ^{about 14 mmol h -1} g ^{-1, and when used alone} It may have a hydrogen generation rate of 3.46 mmol h ^-1 g ^-1.

Unlike the photocatalyst of the present application with the staggered release bonding, the conventional photocatalyst for generating hydrogen is advantageously bonded by the straddling release bonding. In this case, the photocatalyst for generating hydrogen may have a high rate of hydrogen generation due to separation of electrons and holes of the titanium dioxide composite, localization of electrons and holes, and excitation by light of various wavelengths.

According to the exemplary embodiment of the present disclosure, the diameter of the fine dust may be 1 μm to 100 μm, but is not limited thereto.

For example, the diameter of the fine dust is about 1 μm to about 100 μm, about 10 μm to about 100 μm, about 20 μm to about 100 μm, about 30 μm to about 100 μm, about 40 μm to about 100 μm, About 50 μm to about 100 μm, about 60 μm to about 100 μm, about 70 μm to about 100 μm, about 80 μm to about 100 μm, about 90 μm to about 100 μm, about 1 μm to about 90 μm, about 1 μm to about 80 μm, about 1 μm to about 70 μm, about 1 μm to about 60 μm, about 1 μm to about 50 μm, about 1 μm to about 40 μm, about 1 μm to about 30 μm, about 1 μm to About 20 μm, about 1 μm to about 10 μm, about 10 μm to about 90 μm, about 20 μm to about 80 μm, about 30 μm to about 70 μm, about 40 μm to about 60 μm, or about 50 μm However, it is not limited thereto.

The photocatalyst according to the present application can effectively remove PM10, that is, fine dust having a diameter of less than 10 μm.

According to one embodiment of the present application, the organic pollutants are methylene blue, nitrogen oxides (NO _x ), ammonia (NH ₃ ), methyl mercaptan, formaldehyde, and acetaldehyde. ), and combinations thereof, but are not limited thereto.

The organic pollutants may generally refer to substances contained in cigarette smoke, but are also contained in various products used in modern society such as cosmetics, dyes, and adhesives. By using the photocatalyst according to the present application, it is possible to remove the organic contaminants that may adversely affect the human body or the natural environment.

The present invention is to be described in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[Example 1]

First, 0.5 g of titanium dioxide (P25: manufactured by DEGUSA, 70% of anatase, 30% of rutile), and 0.8 g of Li were added to a round bottom flask. Subsequently, after making the flask in a vacuum state and adding nitrogen, 50 mL of ethylenediamine (EDA) (manufactured by TCI) was added and reacted over 7 days to produce blue titanium dioxide with reduced rutile phase. (7 Blue TiO ₂ , 7BT).

Next, referring to FIG. 4, the reduced titanium dioxide, WO ₃ and silver nitrate (AgNO ₃ ) were mixed in DI water, and then irradiated with ultraviolet rays of 365 nm wavelength at room temperature for 3 hours to obtain a titanium dioxide composite 7BT/W1- Az was prepared (however, z is 0.5 to 2.0).

_{In the description of "x} BT/W _y -A _z " of the present example, x is the time taken when selectively reducing blue titanium dioxide (BT), y is the ratio of WO ₃ to the BT, and z is titanium dioxide It represents parts by weight of Ag particles per 100 parts by weight of the composite.

In this regard, the ratio between the mass part _{of the reduced titanium dioxide and the mass part of WO 3} with respect to 100 parts by weight of the titanium dioxide composite is 1:1.

5A and 5B are TEM images of the titanium dioxide composite according to Example 1, and FIG. 6 is an HADDF-STEM and EDS image according to Example 1.

5, 7BT of the 7BT/W1-A1 has an anatase phase as (101) crystalline, WO ₃ has (100) crystal, and Ag has (111) crystal. In addition, the interlayer spacing d of the crystal was measured as _{7BT 0.351 nm, Ag 0.242 nm, and WO 3 0.392 nm.}

Referring to FIG. 6 _{, Ag was doped or adhered on 7BT and WO 3} , and elements other than Ti, W, O, and Ag were not detected on the 7BT/W1-A1.

[Example 2]

In the process of Example 1, 1.1 g of Na was added instead of 0.8 g of Li to prepare blue titanium dioxide with reduced anatase phase, and _{then reacted with WO 3} _{and AgNO 3} to obtain a titanium dioxide complex.

[Example 3]

1.0 g of Blue TiO ₂ was dispersed in 30 mL of deionized water, 2.90 g of WO ₃ was dispersed in 100 mL of methanol, and then the deionized water and the methanol were sonicated to sufficiently disperse. Subsequently, after mixing the deionized water and the methanol, UV100 illumination (λ = 365 nm) was irradiated for 3 hours, followed by filtration and drying with ethanol and deionized water.

In this regard, the step of irradiating the UV100 illumination may be omitted.

[Example 4]

The third embodiment of the Blue TiO ₂ -WO ₃ 1 g to 1 mg of the N ₂ gas flow with stirring was dispersed in 5 ml of methanol AgNO ₃ was fed to the methanol. Subsequently, the methanol was irradiated at room temperature for 3 hours under UV100 illumination (λ = 365 nm). The resulting solution was washed several times with deionized water, ethanol, and acetone, and then dried in a vacuum oven at 60° C. for 1 hour to obtain a dark red Blue TiO ₂ -WO ₃ -Ag.

[Example 5]

The third embodiment of the Blue TiO ₂ / WO ₃ 5 g was dispersed in 25 ml of ethanol, NiCl ₂ · 6H ₂ O 4.46 mg and dispersed to the deionized water 100 ml three cars. Subsequently, the ethanol and the tertiary deionized water were mixed, sonicated for 1 hour, and then the pH was adjusted to 8 using a 0.1 M NaOH solution.

Subsequently, the mixture was _{irradiated with UV100 illumination (λ = 365 nm) for 3 hours under N 2} gas at room temperature, washed several times with deionized water, ethanol and acetone, and dried in a vacuum oven at 60° C. for 1 hour to Blue TiO _2- WO ₃ -Ni was prepared.

[Example 6]

The third embodiment of the Blue TiO ₂ / WO ₃ 1.5 g was dispersed in 25 ml of ethanol, was mixed with 0.02 M Cu (NO ₃₎ ₂ solution in 100 ml and sonicated for 1 hour. Subsequently, after adjusting the pH to 9.5 with a 0.1 M NaOH solution, it was irradiated under UV100 illumination (λ = 365 nm) for 3 hours under _{N 2 gas at room temperature.} Subsequently, the solution was washed several times with deionized water, ethanol and acetone, and dried in a vacuum oven at 60° C. for 1 hour to obtain Blue TiO ₂ -WO ₃ -Cu.

[Example 7]

The third embodiment of the Blue TiO ₂ / WO ₃ 1.5 g was dispersed in 25 ml of ethanol, was mixed with 100 ml 0.02 M FeCl ₃ solution and sonicated for 1 hour. Subsequently, 1 M of NaBH ₄ solution was added, followed by irradiation under UV100 illumination (λ = 365 nm) for 3 hours under _{N 2 gas at room temperature.} Subsequently, the solution was washed several times with deionized water, ethanol and acetone, and dried in a vacuum oven at 60° C. for 1 hour to obtain Blue TiO ₂ -WO ₃ -Fe.

[Example 8]

The third embodiment of the Blue TiO ₂ / WO ₃ 1.5 g was dispersed in 25 ml of ethanol, was mixed with 100 ml of the _{_{Cu (NO 3) 2 0.02 M}} FeCl of the solution and 100 ml ₃ solution and sonicated for 1 hour. Subsequently, 1 M of NaBH ₄ solution was added, followed by irradiation under UV100 illumination (λ = 365 nm) for 3 hours under _{N 2 gas at room temperature.} Subsequently, the solution was washed several times with deionized water, ethanol and acetone, and dried in a vacuum oven at 60° C. for 1 hour to obtain Blue TiO ₂ -WO ₃ -Fe/Cu.

[Comparative Example]

Comparative examples according to the present application include only some of the materials used in the above examples, such as P25, 7BT, Ag nanoparticles, WO ₃ , 7BT/W1, W1-A1, 7BT-A1, or performing a process without a specific material. Means substances.

[Experimental Example 1]

7A is an XRD analysis of the material according to Example 1 and Comparative Example, b and c are XPS analysis of the material according to the comparative example, and d to f are XPS analysis of the material according to Example 1 It was analyzed.

Referring to FIG. 7, it can be seen that 7BT/W1-A1 includes all of Ag nanoparticles (JCPDS 1-1164 Ag), 7BT, and WO _3. In addition, unlike P25, since the Ti 2p and O1s core-level XPS spectra of 7BT show a peak shift to low binding energy, it can be confirmed that the ^{7BT transfers electrons to form Ti 3+ and oxygen defects.} Moreover, the 7BT/W1-A1 showed correct peak splitting (2.2 eV) between the _{4f 7/2} and 4f _5/2 double peaks, including ^{W 6+} , and two weak peaks for _{Ag 2 O formation (3d} _5/2 ) is observed, and it can be confirmed that Ti-O, OW, and OH bonds are present.

[Experimental Example 2]

8A and 8B are UV-Vis spectra of materials according to the Examples and Comparative Examples, c is a Tauc plot of the material according to the Comparative Example, and d is The VB-XPS spectrum of the material, e is the PL spectrum, and f is the photoresponse data. In this regard, ①, ②, and ③ in c and d of FIG. 8 _{mean the x-intercepts of the WO 3} pure tangent, the 7BT tangent, and the P25 tangent, respectively.

①, ②, and ③ of Fig. 8 c mean 2.58 eV, 2.69 eV, and 3.10 eV, respectively, and ①, ②, and ③ of Fig. 8 d mean 3.32 eV, 1.14 eV, and 2.25 eV, respectively do.

Referring to FIG. 8A, 7BT-A1 can evenly absorb light of 300 nm to 800 nm, and 7BT/W1-A1 can absorb more light of about 550 nm or less than that of 7BT-A1. Was observed to be. Therefore, it can be seen that more light is absorbed by Ag nanoparticles formed after combining _{7BT with WO 3} than simply forming Ag nanoparticles on 7BT. As will be described later, the 7BT-A1 only absorbs a lot of light, and the production of carbon monoxide is small and the photocatalytic electron reaction rate is low, so it is preferable to use the 7BT/W1-A1 in order to produce carbon monoxide.

In addition, referring to b to d of FIG. 8, it was confirmed that the greater the Ag in the 7BT/W1-Az, the stronger the localized surface plasmon resonance (LSPR) phenomenon was expressed, thereby absorbing more light. The VB-XPS results of P25, 7BT, and WO ₃ were measured as 2.25 eV, 1.14 eV, and 3.32 eV (vs. NHE), respectively.

In addition, referring to e and f of FIG. 8, unlike 7BT/W1, WO ₃ , and 7BT, 7BT/W1-A1 had a very high photocurrent measured and the intensity of the spectrum was constant. It can be seen that the and holes are efficiently separated.

[Experimental Example 3]

9A is a gas chromatography of the materials according to Example 1 and Comparative Example, and b to d are graphs of CO generation over time.

Referring to FIG. 9, 7BT/W1-A1 and 7BT-A1 can selectively generate only carbon monoxide, unlike 7BT and 7BT/W1. It was found to be excellent.

In addition, the 7BT/W1-A1 can produce carbon monoxide constantly even if it is used 5 times, so it can be recycled, and it can generate more carbon monoxide than the 7BT or 7BT/Wy.

10A and 10B are graphs of photocatalytic properties of materials according to Example 1 and Comparative Example.

Referring to FIG. 10, 7BT/W1-A1 may have a higher photocatalytic electron reaction rate (2333.44 μmol g ^-1 h ^-1 ) and higher selectivity for carbon monoxide production compared to 7BT/W1, which is 7BT/W1- This is because when A1 is irradiated with light, electrons are generated by Ag, and efficient electron-hole separation occurs.

Specifically, the photocatalytic electrons' rate and the production amount and selectivity of hydrogen, methane, and carbon monoxide of the materials of Example 1 and Comparative Example were analyzed as shown in Table 1 below.

[Table 1]

In Table 1, the photocatalytic electron reaction rate _{can be obtained as 2[H 2} ]+8[CH ₄ ]+2[CO], and the selectivity is [H ₂ ], [CH] in the photocatalytic electron reaction rate. ₄ ], and [CO].

In this regard, it can be seen that 7BT/W1-A1 can selectively produce only CO and a photocatalytic electron reaction rate that is far superior to other materials.

[Experimental Example 4]

11A and 11B are graphs of the PL spectrum and intensity of the material according to the comparative example, and c and d are graphs of the band structure of the material according to the comparative example.

The PL intensity of the photocatalyst according to the present application is proportional to the amount of ^OH-radicals. At this time, referring to a and b of FIG. 11, ^{it can be seen that the formation of OH-} radicals hardly occurs because the peak of 7BT is not observed, and the peak of 7BT/W1 at 488 nm is much higher than _{the peak of WO 3} Therefore, it can be confirmed that the holes of the 7BT/W1 photocatalyst are _{generated faster than that of WO 3.}

Therefore, it can be seen that the movement of electrons in 7BT/W1 may be performed in a form such as a Z-scheme, not a type II (c in FIG. 11).

[Experimental Example 5]

12 is a graph showing the decomposition of tobacco smoke of a material according to the embodiment.

Referring to FIG. 12, it can be seen that the photocatalyst including 7BT/W1-A1 removes fine dust with a diameter of 2.5 μm or less over time.

The foregoing description of the present application is for illustrative purposes only, and those of ordinary skill in the art to which the present application pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present application is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present application.

Claims

A reduced titanium dioxide (TiO 2 ) including an anatase phase and a rutile phase, and any one of the anatase phase and the rutile phase is reduced; And

A metal oxide combined with the reduced titanium dioxide;

Containing,

Titanium dioxide complex.
The method of claim 1,

The titanium dioxide composite further comprises the reduced titanium dioxide or metal nanoparticles formed on the metal oxide, titanium dioxide composite.
The method of claim 2,

With respect to 100 parts by weight of the titanium dioxide composite, the metal nanoparticles are less than 10 parts by weight, and the metal oxide is 30 parts by weight to 70 parts by weight, the titanium dioxide composite.
The method of claim 2,

The metal nanoparticles supply electrons onto the reduced titanium dioxide, a titanium dioxide composite.
The method of claim 2,

The metal nanoparticles will have a diameter of 1 nm to 10 nm, titanium dioxide composite.
The method of claim 2,

The metal nanoparticles are composed of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof. It will contain a metal element selected from the group, titanium dioxide composite.
The method of claim 1,

A reduction reaction occurs in the reduced titanium dioxide, and an oxidation reaction occurs in the metal oxide, a titanium dioxide composite.
The method of claim 1,

A conduction band of the metal oxide is greater than a valence band of the reduced titanium dioxide and smaller than a conduction band of the reduced titanium dioxide.
The method of claim 8,

The reduced titanium dioxide band gap (band gap) is greater than the band gap (band gap) of the metal oxide, titanium dioxide composite.
The method of claim 1,

The metal oxides are W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ti, Ca, Nb, K, Na, Li, and a titanium dioxide composite comprising a metal element selected from the group consisting of combinations thereof.
The method of claim 1,

The reduced titanium dioxide will exhibit a blue color, titanium dioxide complex.
The method of claim 1,

The reduced titanium dioxide particles and the metal oxide particles each independently have a diameter of 10 nm to 100 nm, titanium dioxide composite.
Mixing titanium dioxide (TiO 2 ) including an anatase phase and a rutile phase with a reducing agent to selectively reduce any one of the anatase phase and the rutile phase to form reduced titanium dioxide; And

Dispersing the reduced titanium dioxide and metal oxide in a solvent and then irradiating light to prepare a titanium dioxide composite;

Containing,

Method for producing a titanium dioxide composite.
The method of claim 13,

The step of preparing the titanium dioxide composite further comprises the step of introducing a metal salt containing metal nanoparticles into the solvent.
The method of claim 14,

The metal salt is a group consisting of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof It will contain a metal element selected from, a method for producing a titanium dioxide composite.
The method of claim 13,

The reducing agent will contain a metal and a basic organic solvent, a method for producing a titanium dioxide composite.
The method of claim 16,

The metal comprises a metal selected from the group consisting of Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, and combinations thereof. Way.
The method of claim 16,

The basic organic solvent is a material selected from the group consisting of alkyl amine, dialkyl amine, cyclicalkyl amine, dicyclicalkyl amine, and combinations thereof Including that, a method for producing a titanium dioxide composite.
A photocatalyst comprising the titanium dioxide complex according to any one of claims 1 to 12.