KR101109991B1 - Visible light active nanohybrid photocatalyst and manufacuring method thereof - Google Patents

Abstract

The present invention relates to a visible light-responsive nanohybrid photocatalyst material and a method for manufacturing the same, and the present invention is characterized in that a visible light-responsive photocatalyst material is prepared by hybridizing a peelable layered titanium oxide and a transition metal compound. The visible light responsive photocatalyst material prepared by the manufacturing method of the present invention is chemically very stable, has a particularly large specific surface area, and can act as an excellent photocatalyst in the visible light range, thereby decomposing or decomposing organic substances, which are the main causes of environmental pollution. It is very useful in many aspects such as producing hydrogen gas.

Description

Visible light active nanohybrid photocatalyst and manufacuring method

The present invention relates to a visible light responsive nanohybrid photocatalyst material and a method for preparing the same.

In general, photocatalyst is a material having strong redox ability by light energy, and by such photocatalytic action, it can sterilize, antibacterial, decompose, antifouling, deodorize and collect adhesion substances on the material surface, contaminants in air and solution. . Therefore, photocatalyst is used for a wide range of applications such as cooler filter, glass, tile, exterior wall, food, factory interior wall, metal products, water tank, marine pollution purification, construction materials, mold prevention, UV protection, water purification, atmospheric purification, hospital infection prevention. .

Among these photocatalysts, titanium dioxide (TiO ₂ ), which has various advantages such as excellent photoactivity, chemical or biological stability, and durability, is mainly used, and a typical commercially available product is P-25 ™ (nano size powder). Degussa, Germany).

However, in the case of the P-25, nano-size anatase and rutile TiO ₂ are composed of adjacent bonds with each other, so that TiO ₂ , which is a member element thereof, can respond only to ultraviolet rays and thus has low light efficiency under sunlight. Has its drawbacks. Therefore, in order to utilize the light energy in the visible light region, which accounts for about 70% of sunlight, it is required to develop a new visible light responsive photocatalyst having excellent light efficiency.

Attempts have been made to control the bandgap energy in order to solve the above problems, but the visible light responsiveness has not been efficiently improved by simply physically mixing titanium dioxide (TiO ₂ ) and a transition metal compound. In addition, attempts have been made to develop nanohybrid photocatalysts between transition metal oxides and titanium oxides using ion exchange methods, but it is difficult to synthesize hybrid structures because ion exchange methods cannot effectively stabilize interlayers between layers. No visible light responsive photocatalyst could be developed.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a visible light responsive photocatalyst material that is chemically stable, has a large specific surface area, and has excellent photocatalytic efficiency in visible light, and a simple and economical method for preparing the same.

In order to achieve the above technical problem, the present invention provides a method for producing a visible light responsive photocatalyst material, characterized in that the hybridization of the peelable titanium oxide and the transition metal compound.

Preferably, the present invention comprises the steps of preparing a titanium oxide (S1); (S2) ion-exchanging the proton (H ⁺ ) by acid treatment of the titanium oxide of step (S1); (S3) (c) cationic treatment of the titanium oxide ion-exchanged with the protons to ion exchange protons with cations or (ii) adding an amine compound to bind the amine compound to the protons to produce a peeled titanium oxide having negative charge step; (S4) preparing a hybrid of the titanium oxide and the transition metal compound by reacting the stripped titanium oxide and the transition metal oxide or the transition metal chalcogenide of step (S3); Provide a method.

More preferably, the present invention provides Cs _y Ti _{2 -y / 4} O ₄ , wherein the exfoliable titanium oxide is y is a number between 0.67 and 0.73, K ₂ Ti ₂ O ₅ , K ₂ Ti ₄ O _{9 ,} Na ₂ Ti ₃ O ₇ , Cs ₂ Ti ₅ O ₁₂ , KTiNbO ₅ , CsTi ₂ NbO ₇ , KTi ₃ NbO ₉ And K ₃ Ti ₅ NbO _{14 It} provides a method for producing a visible light responsive photocatalyst material, characterized in that any one selected from the group consisting of.

More preferably, the present invention comprises the steps of preparing (S1) Cs _y Ti _{2 -y / 4} O ₄ ; (S2) preparing the _{Cs y Ti 2-y / 4} O ions H _y Ti _{2 -y / 4} O exchange ₄ to the acid treatment with proton ^{_{(H +) 4 H 2 O}} ?; (S3) cation treatment of H _y Ti _{2 -y / 4} O ₄ -H ₂ O with (iii) cation to ion exchange protons with cations, or (ii) add an amine compound to bind an amine compound to the proton to have a negative charge. Preparing a peeled titanium oxide; And (S4) reacting the exfoliated titanium oxide with a transition metal oxide or a transition metal chalcogenide to prepare a hybrid of the titanium oxide and the transition metal compound, and providing a visible light responsive photocatalyst material.

More preferably, the present invention provides a method for producing a visible light responsive photocatalyst material, characterized in that y of Cs _y Ti _{2 -y / 4} O ₄ is 0.67.

More preferably, the present invention comprises the steps of mixing the Cs _y Ti _{2 -y / 4} O ₄ (s1) cesium carbonate (Cs ₂ CO ₃ ) and titanium dioxide (TiO ₂ ); And (s2) heat-treating the mixture to provide a method of manufacturing a visible light responsive photocatalyst material.

Preferably, the present invention provides a method for producing a visible light responsive photocatalyst material, characterized in that it further comprises the step of heat-treating the hybrid prepared in the step (S4), more preferably, the present invention It provides a method for producing a visible light responsive photocatalyst material, characterized in that carried out at 200 to 400 ℃.

Preferably, the present invention provides a method for producing a visible light responsive photocatalyst material, characterized in that the acid of step (S2) is a strong acid, and more preferably, the present invention is from the group consisting of hydrochloric acid, nitric acid and sulfuric acid. It provides a method of producing a visible light responsive photocatalyst material, characterized in that at least one selected.

Preferably, the present invention provides a method for producing a visible light-responsive photocatalyst material, characterized in that the cation treatment of step (S3) uses an organic ammonium cation, and more preferably, the organic ammonium cation is TBAOH (Tetrabutylammonium). hydroxide), TPA-OH (Tetrapropylammonium hydroxide), TEA-OH (Tetraethylammonium hydroxide) and TMA-OH (Tetramethylammonium hydroxide) provides a method for producing a visible light-responsive photocatalyst material, characterized in that at least one selected from the group consisting of: Most preferably the organic ammonium cation is TBAOH (Tetrabutylammonium hydroxide).

Preferably, the present invention is a visible light-responsive photocatalyst material, characterized in that the amine compound of step (S3) is any one selected from the group consisting of hexylamine, octahexylamine, and mixtures thereof. It provides a manufacturing method.

Preferably, the present invention provides a method for producing a visible light responsive photocatalyst material, characterized in that the transition metal of the above-described manufacturing method is a transition metal capable of absorbing visible light, and more preferably, the present invention absorbs the visible light. It provides a method for producing a visible light-responsive photocatalyst material, characterized in that the transition metal is at least one selected from the group consisting of Cr, Co, Ni, Cu and Zn.

Preferably, the present invention provides a method for producing a visible light responsive photocatalyst material, characterized in that the transition metal oxide of step (S4) is a metal acetate.

The present invention also provides a visible light responsive photocatalyst material represented by the following formula (1).

[Formula 1]

Transition Metal-O _x -Ti _{2 -y / 4} -O ₄

In Formula 1, x is a variable according to the type of transition metal, y is a number between 0.67 and 0.73.

Preferably, the present invention provides a visible light responsive photocatalyst material, characterized in that y of Formula 1 is 0.67.

Preferably, the present invention provides a visible light responsive photocatalyst material, characterized in that the transition metal of Formula 1 is any one selected from the group consisting of Cr, Co, Ni, Cu and Zn.

Hereinafter, the visible light responsive photocatalyst material of the present invention and a manufacturing method thereof will be described in more detail.

The present invention relates to a visible light responsive photocatalyst material which improves visible light responsiveness, specific surface area, and stability by hybridizing two semiconductor compounds having different band gaps, and a method of manufacturing the same. It is based on controlling the bandgap by hybridizing a transition metal compound having a smaller bandgap to a titanium dioxide semiconductor having. In other words, by combining two semiconductor materials and creating a covalent bond through heat treatment under appropriate conditions, impurity levels are induced in the band gap to impart visible light responsiveness. In particular, in the case of hybrids with titanium dioxide and transition metal sol particles having a small bandgap with visible light responsiveness, these hybridized compounds have lower bandgap energy and lower valence bands than titanium dioxide, so that visible light irradiation Holes are generated in the valence band by electron transition from the valence band of the sol particles to the conduction band. These holes can easily migrate to the valence band of titanium dioxide with higher energy. Therefore, the hybridized compound can minimize the recombination reaction between electrons and holes, and thus can be used to decompose water or organic matter more effectively. In addition, the transition metal nanosol particles stabilized between layers are expected to greatly improve the chemical stability of the particles themselves, and furthermore, these materials have a crosslinked structure with porosity, which is expected to result in better water decomposition and organic decomposition properties. do. As described above, attempts have been made to synthesize these crosslinking materials using ion exchange, but hybrid materials have not been properly synthesized because the transition metal nanoparticles are not effectively ion exchanged between layers. In contrast, the production method of the present invention has an excellent advantage that the transition metal nanoparticles can be reliably stabilized between layers since the titanium dioxide layer is completely peeled off (separated) and then recombined with the transition metal compound.

The manufacturing method according to the preferred embodiment of the present invention includes preparing a titanium oxide (S1). The titanium oxide which can be peeled off in the step (S3) to be described later includes Cs _y Ti _{2 -y / 4} O ₄ , K ₂ Ti ₂ O ₅ , Na ₂ Ti ₃ O ₇ , CsTi ₅ O ₁₂ , and KTiNbO having a layered structure. ₅ , CsTi ₂ NbO ₇ , KTi ₃ NbO ₉ , K ₃ Ti ₅ NbO _14, and the like may be used, and any titanium oxide capable of exfoliation in the process described below may be used.

On the other hand, Cs _y Ti _{2 -y / 4} O ₄ is more preferable because it is easier to exfoliation process and recombination described later, and thus the transition metal compound, which is to be achieved by the present invention, is stably bonded between the titanium oxide layers and has structural features. A visible light responsive photocatalyst material having a large specific surface area can be prepared. Such Cs _y Ti _{2 -y / 4} O ₄ may include, for example, (s1) mixing cesium carbonate (Cs ₂ CO ₃ ) and titanium dioxide (TiO ₂ ); And (s2) heat treating the mixture. However, the present invention is not limited thereto. That is, cesium carbonate and titanium dioxide are well mixed in accordance with chemical amounts, and then milled, and Cs _y Ti _{2 -y / 4} O ₄ having a layered structure may be manufactured through repeated heat treatment.

The value of y in Cs _y Ti _{2 -y / 4} O ₄ is an important factor in determining whether the precursor layer structure can maintain charge balance with cesium ions, and y is preferably a number of 0.67 to 0.73, and y is 0.67. In the case of, it is more preferable that the layered structure is maintained.

The preparation method according to a preferred embodiment of the present invention also includes the step of (S2) ion-exchanging the proton (H ⁺ ) by acid treatment of the titanium oxide of step (S1). Specifically, when Cs _y Ti _{2 -y / 4} O ₄ is used as the titanium oxide, the present invention is acid-treated with Cs _y Ti _{2 -y / 4} O ₄ prepared in step (S1), and cesium ions are protons ( H ⁺ ) ion-exchanged H _y Ti _{2 -y / 4} O _{4 It} will include the step of preparing a H ₂ O.

The layered peelable titanium oxide, such as Cs _y Ti _{2 -y / 4} O ₄ , has a structure in which cations (in the case of Cs _y Ti _{2 -y / 4} O ₄ ) are present in a structure between titanium oxide layers. When acid treatment is carried out, cations can be ion exchanged into protons.

The acid used in the step (S1) is not limited as long as it can provide a proton, but is preferably a strong acid for ease of proton ion exchange, more preferably hydrochloric acid, nitric acid, sulfuric acid, and the like, and hydrochloric acid. It is most preferable in terms of ion exchange efficiency.

The preparation method according to the preferred embodiment of the present invention also includes (S3) cation treatment of the titanium oxide ion-exchanged with the protons to ion exchange protons with cations or (ii) adding an amine compound to the protons. Preparing a peeled titanium oxide having a negative charge by combining the same. Specifically, when Cs _y Ti _{2 -y / 4} O ₄ is used as the titanium oxide, the present invention provides a proton by (C) cation treatment of the H _y Ti _{2 -y / 4} O ₄ H H ₂ O (S3). Ion-exchanged with a cation or (ii) adding an amine compound to bind an amine compound to a proton to produce a negatively charged exfoliated titanium oxide.

When the proton is ion-exchanged with a cation by the cation treatment or the amine compound is added to bind the amine compound to the proton, a bulky cation or an amine compound is present between the titanium oxide layers and the titanium oxide layer is peeled off.

At this time, the cation providing material that can be used is large enough to separate and exfoliate the titanium oxide layer, and any cation can be used if ion exchange is possible with the proton, and TBA? OH ( Tetrabutylammonium hydroxide), TPA-OH (Tetrapropylammonium hydroxide), TEA-OH (Tetraethylammonium hydroxide), TMA-OH (Tetramethylammonium hydroxide) It is preferable to use any one or more selected from the group consisting of salts containing organic ammonium cations, such as TBA OH is most preferred in terms of peeling efficiency.

Meanwhile, as the amine compound that can be used, any amine compound can be used as long as it is large enough to separate and separate the titanium oxide layer, and can bind to protons. Hexylamine, hexylamine, Octhexylamine and mixtures thereof are preferred.

The manufacturing method according to the preferred embodiment of the present invention also includes the step of preparing a hybrid of the titanium oxide and the transition metal compound (S4) by reacting the exfoliated titanium oxide and the transition metal compound. Reaction of the negatively charged titanium oxide, the transition metal oxide, the transition metal chalcogenide, etc., peeled off in the above-described steps, and the rearrangement of the titanium oxide is chemically stable, has a large specific surface area, and has a very high visible light response. Can be prepared.

Any metal can be used as long as it can absorb visible light as the transition metal that can be used in the manufacturing method, but it is preferable to use Cr, Co, Ni, Cu, or Zn in view of absorbing visible light.

In addition, it is preferable to use M (CH ₃ OOH), a metal acetate, as a compound providing a transition metal to be intercalated between the exfoliated titanium oxide layers, and to use the transition metal Cr, Co, Ni, Cu or Zn as the metal M. It is more preferable in terms of solubility.

One preferred embodiment of the present invention further includes the step of heat-treating the hybrid made in the above-mentioned step (S4), and more preferably further comprises the step of heat-treating to 200 to 400 ℃. In inorganic-inorganic nanohybrid compounds, it is very important to improve the electrical connection between semiconductors through heat treatment to improve photocatalytic performance. That is, it is important to effectively remove the organic matter remaining between the lattice while maintaining the porous hybrid structure through heat treatment, and in particular, the manufacturing method including the exfoliation step and the recombination step of the present invention is a nanohybrid compound compared to the conventional ion exchange method. It is very effective in increasing the thermal stability of and is a very useful method for synthesizing new visible light-responsive photocatalyst compounds because it increases specific surface area with porous structure. If the heat treatment temperature is 200 to 400 ℃ can effectively remove the organic matter remaining in the hybrid structure without destroying the hybrid structure.

The present invention also provides a visible light responsive photocatalyst material represented by the following formula (1).

<Formula 1>

Transition Metal-O _x -Ti _{2 -y / 4} -O ₄

In Formula 1, x is a variable according to the type of transition metal, y is a number between 0.67 and 0.73, most preferably when y is 0.67.

The present invention also provides a visible light responsive photocatalyst material, characterized in that the transition metal is any one selected from the group consisting of transition metals capable of absorbing visible light such as Cr, Co, Ni, Cu, Zn.

The present invention provides a visible light-responsive nanohybrid photocatalyst material that is chemically stable, has a large specific surface area, and has excellent photocatalytic activity, and a method of preparing the same. The visible light responsive photocatalyst material of the present invention can be usefully used to produce hydrogen gas through water decomposition or to decompose organic substances that cause environmental pollution.

1 is a measurement CrO _x -Ti O _{1 .83} a powder X- ray diffraction (powder X-ray diffraction) evaluating the crystallinity and thermal stability of _4, according to an embodiment of the invention the chart.
Figure 2 is a measure of the crystal structure of the CrO _x -Ti _{1 .83} O ₄ according to one embodiment of the present invention using a transmission electron microscope (transmission electron microscopy) graph.
Figure 3 is a measured graph using the UV-VIS spectroscopy in order to determine the band structure of the CrO _x -Ti _{1 .83} O ₄ according to one embodiment of the present invention.
Figure 4 is a photograph taken in the CrO _x -Ti _{1 .83} O ₄ according to one embodiment of the invention the scanning electron microscope (SEM).
Figure 5 is a graph BET measurement for measuring the specific surface area of the CrO _x -Ti _{1 .83} O ₄ according to one embodiment of the present invention.
Figure 6 is a assess CrO _x -Ti _{1 .83} O ₄ photocatalytic activity orange acid 7 in the visible light range to the results for the evaluation of (Acid orange 7, AO7) Decomposition degree in accordance with an embodiment of the present invention graph .
Figure 7a is a rate the degree of phenol degradation in one embodiment the visible light range to the results for evaluating the photocatalytic activity of the CrO _x -Ti _{1 .83} O ₄ according to an embodiment of the present invention, the graph.
Figure 7b is a assess the concentration of carbon dioxide generated by the decomposition of phenol in the visible light range to the results for evaluating the photocatalytic activity of the CrO _x -Ti _{1 .83} O ₄ according to one embodiment of the invention the chart.
FIG. 8 is a photograph showing a tindall phenomenon of the peeled titanium oxide colloidal solution prepared after step (S3) of the manufacturing method of the present invention.
Figure 9 is a measurement NiO _x -Ti O _{1 .83} a powder X- ray diffraction (Powder X-ray diffraction) evaluating the crystallinity and thermal stability of _4, according to an embodiment of the invention the chart.
Figure 10 is a MO _x -Ti, which are one embodiment of the present invention _{1 .83} O ₄ Powder X-ray diffraction measurement graph evaluating the crystallinity and thermal stability of (M = Co, Ni, Cu and Zn).
11 is a MO _x -Ti, which are one embodiment of the present invention _{1 .83} O ₄ (M = Co, Ni, Cu and Zn) are photographs taken with an electron scanning microscope (SEM).
12 is a graph BET measurement for measuring the specific surface area of the _{MO x -Ti 1 .83 O 4 (} M = Co, Ni, Cu and Zn), which are one embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention is not limited to the examples described below.

Preparation of <Example _{1> Cs 0 .67 Ti 1 .83} O 4

A cesium carbonate (Cs ₂ CO ₃₎ and titanium dioxide (TiO ₂₎ the use of the Cs _{0 .67} Ti _{1 .83} O ₄ was prepared. Cesium carbonate and titanium dioxide were mixed well in accordance with the chemical weight, and finely mixed for about 1 hour in the mortar at the same time, and then heat-treated in 750 ° C. for 24 hours. For the optimized synthesis, the heat treated compound was finely divided again, and then a specimen was prepared and heat treated again in an air at 800 ° C. for 24 hours. As a result, Cs _0.67 Ti _1.83 O _{4 in the} form of lepidocrocite having a solid and orthorhombic layer structure was produced.

<Example 2> Preparation of _{H 0 .67 Ti 1 .83 O 4} ? H 2 O through the ion exchange

Example 1 The acid treatment by the production of Cs _{0 .67} Ti _{1 .83} O ₄ Ion-exchange of protons (H ⁺⁾ in H _{0.67 Ti 1.83 O 4? H 2} O was prepared. First, into a 1M aqueous solution of hydrochloric acid per 100㎖ _{Cs 0 1g .67 Ti 1 .83 O} 4 was vigorously stirred. At this time, it was repeated five times while changing a new acid aqueous solution every day for three days. Acid treated powders were collected using a centrifuge and dried in an oven at 60 ° C. to remove moisture. The dried to ensure that the X-ray diffraction analysis of the Cs _0.67 Ti _1.83 O ₄ Cs ions are ion-exchanged with protons (H ^+), instead it was confirmed that the _{H 0 .67 Ti 1 .83 O 4} ? H 2 O is formed.

<Example _{3> H 0 .67 Ti 1 .83} O 4? Preparation of titanium oxide stripping with a proton of the H ₂ O as the cation exchange

Example 2 Preparation of the _{H 0 .67 Ti 1 .83 O 4} ? H 2 O to prepare a titanium oxide having a negative charge separation in the cationic treatment. First, the _{H 0 .67 Ti 1 .83 O 4} ? To the next separation, the titanium oxide finely between the H ₂ O samples, _{H 0 .67 Ti 1 .83 O 4} ? H ₂ O per 0.4g sample of distilled water 100㎖ scored sufficiently to be 1: put a bulky (bulky) a cation of TBA OH (Tetrabuthylammonium hydroxide) to H _{0 .67} Ti _{1 .83} O ₄ mol (mole) ratio of 3 and H ₂ O sample ??. The mixed solution was then vigorously stirred for 10 days. After a centrifuge to separate the cationic ion exchange is not _{H 0 .67 Ti 1 .83 O 4} ? H 2 O in the sample separated by (10,000 rpm, 10 minutes) and collected the supernatant was placed aside. At this time, the supernatant was cloudy, and as shown in FIG. 8, the tindle (scattering) phenomenon was observed when the laser was illuminated. Through this process, titanium oxide having a negative charge in the colloidal solution state was obtained.

<Example 4-1> Synthesis of CrO _x -Ti _{1 .83} O ₄

Example by reacting the chromium acetate by the peeling of titanium oxide and titanium oxide interlayer transition metal chromium (Cr) for supplying a material to be inserted into the ion production from the three layer structure of a hybrid compound CrO _x -Ti _{1 .83} O ₄ Was prepared. First, 0.003 mol of chromium acetate per 50 ml of the supernatant peeled titanium oxide collected by the centrifuge of Example 3 was added and reacted at 80 ° C. under reflux for 3 days. This was followed by rinsing with distilled water several times to remove excess chromium acetate and obtaining a precipitate using a centrifuge. At 60 ℃ oven for 12 hours to the precipitate was dried to obtain a CrO _x -Ti _{1 .83} O _4.

<Example 4-2> Synthesis of NiO _x -Ti _{1 .83} O ₄

It was produced in the Examples 4-1 and the hybrid compound using a Ni as the transition metal in place of Cr similar NiO _x -Ti _{1 .83} O _4. 0.01 mole of nickel acetate per 50 ml of the supernatant stripped titanium oxide collected by the centrifuge of Example 3 was reacted at 60-80 ° C. under reflux for 3 days, and the remaining method was the same as in Experiment 4-1. carried out to obtain an NiO _x -Ti _{1 .83} O _4.

<Example 4-3> Synthesis of CoO _x -Ti _{1 .83} O ₄

Were produced in the Examples 4-1 and the hybrid compound using Co as the transition metal in place of Cr similar CoO _x -Ti _{1 .83} O _4. 0.01 mole of cobalt acetate per 50 ml of the supernatant stripped titanium oxide collected by the centrifuge of Example 3 was reacted at a temperature of 60-80 ° C. under reflux for 2-3 days, and the remaining method was Experimental Example 4- carried out in one and the same manner to obtain the CoO _x -Ti _{1 .83} O _4.

<Example 4-4> Synthesis of CuO _x -Ti _{1 .83} O ₄

Were produced in the Examples 4-1 and the hybrid compound using Cu in place of Cr in the transition metal similar to CuO _x -Ti _{1 .83} O _4. 0.02 mole of cobalt acetate per 50 ml of the supernatant peeled titanium oxide collected by the centrifuge of Example 3 was reacted at a temperature of 60-80 ° C. under reflux for 2-3 days, and the remaining method was Experimental Example 4- CuO _x -Ti _1.83 O ₄ was obtained in the same manner as in ₁ .

<Example 4-5> Synthesis of ZnO _x -Ti _{1 .83} O ₄

It was produced in the Examples 4-1 in the hybrid using the Zn in place of Cr in the transition metal compound similar to ZnO _x -Ti _{1 .83} O _4. First, zinc acetate, n-propanol and distilled water were placed in a flask and reacted at 120 ° C. under reflux for 2 hours. The reaction solution was mixed with the peeled supernatant titanium oxide collected by the centrifuge of Example 3 and reacted at 80 ° C. with reflux for 3 days, and the rest of the method was carried out in the same manner as in Experiment 4-1. ZnO _x -Ti ₁ was obtained _.83 O _4.

Experimental Example 1 Powder X-ray diffraction analysis and transmission electron microscopy analysis

Embodiment was subjected to a powder X- ray diffraction analysis for Examples 4-1 to determine the crystallinity and thermal stability of manufacturing a CrO _x -Ti _{1 .83} O ₄ in, respectively under an argon atmosphere for each sample in order to determine the thermal stability Heat treatment was performed for 2 hours. The results are shown in FIG. In the graph of Figure 1 (a) shows the results of H _{0 .67} Ti _{1 .83} O ₄ as a control group, (b) is a pattern measuring _{CrO x -Ti 1.83 O 4 (CT} ) at room temperature, respectively ( c) is 200 ℃, (d) is 300 ℃, (e) shows the result of measuring the CrO _x -Ti _{1 .83} O ₄ 400 ℃ heat treatment and (f) is a 500 ℃.

As shown in Fig. _{1, CrO x -Ti 1 .83 O} 4 can confirm that has a two-dimensional structure thereby (010) peak only visible. In addition, it can be seen that the peak of the heat treatment (010) is moved at a high angle, and as the temperature increases, the distance between layers decreases and the layer is maintained even at a high temperature of 400 ° C. or higher. It can be seen that the two-dimensional crosslinked structure is collapsed because no crystal is seen above 500 ° C.

The crystal structure of the hybrid compound was confirmed using a transmission electron microscope (TEM). A TEM photograph taken by cutting a section of the CrO _x -Ti _{1 .83} O ₄ a heat treatment at 400 ℃ is shown in Fig. The interlayer spacing well matched the interlayer distance value (1.08 nm) determined from the X-ray diffraction analysis was confirmed from the TEM image.

Experimental Example 2 UV-Vis Spectrometer Measurement

Carried out to determine the band structure of the CrO _x -Ti _{1 .83} O ₄ prepared in Example 4-1 was tested using a UV-Vis spectrometer. The results are shown in Fig. In the graph of Figure 3, respectively as a control (a) is the _{Cs 0 .67 Ti 1 .83 O 4} , (e) represents the Cr ₂ O _3, (b) from room temperature to _1.83 CrO _x -Ti O ₄ state patterns, and each (c) is measured in a 200 ℃, (d) is a pattern of measuring the CrO _x -Ti _{1 .83} O ₄ heat-treated at 400 ℃.

As shown in Fig. 3, (b) to (d) of the Cs _{0 .67} Ti _{1 .83} O ₄ is the starting material, (a) and (e) and look for another band position, this CrO _x cluster (cluster) and newly due to hybridization of Ti _{1 .83} O ₄ it means that the have a low band gap energy. Therefore, it was confirmed that the (a) the starting material is capable of absorbing visible light when the CrO _x -Ti _{1 .83} O ₄ structure through hybridization.

Experimental Example 3 Electron Emission Microscopy Measurement

Embodiment the structure of the CrO _x -Ti _{1 .83} O ₄ prepared in Example 4-1 was measured using a scanning electron microscope (SEM). The results are shown in FIG.

As shown in FIG. _{4, CrO x -Ti 1 .83 O} 4 is found to be a layered structure in which a well stacked. This is consistent with showing only the (010) peak, which is a two-dimensional structure in FIG.

Experimental Example 4 BET Measurement

A desorption experiment was carried out - Example 4-1 N ₂ adsorption in order to evaluate the specific surface area of manufacturing a CrO _x -Ti _{1 .83} O ₄ in. The results are shown in FIG.

Experimental results The specific surface area of the starting material, Cs _{0 .67} Ti _{1 .83} O ₄ is about ~ 1m ² g ^-1 inde contrast, CrO _x -Ti _{1 .83} and heat-treated at 300 ℃ and 400 ℃ O ₄ is about ~ 315m You can see that it has increased significantly to ² g ^-1 . In addition, hysteresis is seen, indicating that the interlayer has a porous structure.

Experimental Example 5 Acid Orange 7, AO7 Degradation Experiment

Examples 4-1 the acid orange 7 resolution of manufacturing a CrO _x -Ti _{1 .83} O ₄ was measured in a visible light region (λ> 420nm) from. The concentration of the material used as the photocatalyst was 0.5 g / L, the concentration of AO7 was 50 μM, the pH of AO7 was 3.5, and was carried out under normal laboratory air. The results are shown in FIG. In Fig. 6, □ represents Cr ₂ O ₃ , Δ represents commercially available nano-sized TiO ₂ , P-25 ™ (Degussa, Germany), and ○ represents starting material CsO _{0 .67} Ti _{1 .83} O ₄ . , ▲ is the present invention CrO _x -Ti _{1 .83} O ₄ of the heat-treated at 200 ℃, ● is a heat treatment to the present CrO _x -Ti _{1 .83} O ₄ of the invention heat treated at 300 ℃, ◆ is at 400 ℃ means a CrO _x -Ti _{1 .83} O ₄ of the present invention.

As shown in FIG. 6, P-25 (Δ) starts at a concentration lower than the initial concentration. This is not because P-25 has already decomposed AO7, but is very low due to adsorption on the surface of P-25. When the slope of each of the samples falls from the graph, and _{CrO x -Ti 1 .83 O 4 (} ◆) a heat treatment at 400 ℃ than P-25 (△) has found that the decomposition of AO7 much more effectively, and thus 200 ℃ ( ▲) and the sample heat-treated 400 ° C. than the 300 ° C. (●) heat-treated sample effectively decompose AO7, which means that it is most optimal when heat-treated at 400 ° C. Cr ₂ O ₃ (□) has no photocatalytic activity, but the CrO _x -Ti _1.83 O ₄ (▲, ● and ◆) hybridizes, the transition metal absorbs visible light and the valence band of the total hybridized compound It can be seen that the electron is excited as a conduction band, so that the hole is generated and the photocatalytic activity is observed as the oxidation-reduction reaction of the organic material proceeds.

Experimental Example 6 Phenol Degradation Experiment

* Performing a CrO _x -Ti _{1 .83} O ₄ of the resolution of phenol prepared in Example 4-1 was measured in the visible light region (λ> 420nm). The concentration of the material used as the photocatalyst was 0.5 g / L, the concentration of phenol was 100 μM, the pH of AO7 was 4, and was carried out under normal laboratory air. The results are shown in Figures 7a and 7b. In Fig. 7a, □ represents Cr ₂ O ₃ , Δ represents commercially available nano-sized TiO ₂ P-25 ™ (Degussa, Germany), ○ represents CsO _0.67 Ti _1.83 O ₄ , ▲ represents 200 the present invention CrO _x -Ti _{1 .83} O ₄ of the heat treatment in ℃, ● is the present CrO _x -Ti _{1 .83} O ₄ of the invention heat treated at 300 ℃, ■ of the present invention is heat-treated at 400 ℃ CrO _x -Ti means _1.83 0 ₄ .

As shown in Figure 7a, the control of _{Cs 0 .67 Ti 1 .83 O 4} (○), P-25 (△) , and Cr ₂ O ₃ (□), or are very weak photocatalytic activity, 200 ℃ (▲) And CrO _x -Ti _1.83 O ₄ treated at 300 ° C (●) was unlikely to decompose unlike treatment at 400 ° C (■) as in the decomposition experiment of AO7 of Experimental Example 5. Therefore, when heat-treating the CrO _x -Ti _{1 .83} O ₄ to 400 ℃ can be found that the most optimum conditions.

By measuring the heat treatment the concentration of CrO _x -Ti of _{1 .83} O ₄ phenol degradation experiment when the generated output with CO ₂ at 400 ℃ by gas chromatography. The results are shown in Figure 7b. As shown in FIG. 7B, the phenol decomposition reaction due to the photocatalyst could be confirmed again as CO ₂ gas generated by decomposition of phenol.

<Experiment 7> powder X- ray diffraction analysis of NiO _x -Ti _{1 .83} O ₄

Embodiment was subjected to a powder X- ray diffraction analysis to determine the crystallinity and thermal stability of the NiO _x -Ti _{1 .83} O ₄ prepared in Examples 4-2, respectively, under an argon atmosphere for each sample in order to determine the thermal stability Heat treatment was performed for 2 hours. The results are shown in FIG. In Figure 9, the graph (a) shows the results of the control group of _{H 0 .67 Ti 1 .83 O 4} , (b) is a pattern measuring _{NiO x -Ti 1.83 O 4 (NT} ) at room temperature, respectively ( c) is 200 ℃, (d) is 300 ℃, and (e) is a result obtained by measuring the NiO _x -Ti _{1 .83} O ₄ heat-treated at 400 ℃.

As shown in FIG. 9, it can be seen that they are well stacked in a two-dimensional layered structure which is the (010) peak.

Experimental Example 8 MO _x -Ti _{1 .83} O ₄ X-ray diffraction analysis of (M = Co, Ni, Cu and Zn)

X-ray diffraction analysis similar to Experimental Example 7 was conducted to confirm that various transition metal oxides and titanium oxides could be made a new hybrid compound through a stripping step and a recombination step. The results are shown in FIG. Each (a) in the graph of Fig. 10 _{H 0 .67 Ti 1 .83 O 4} , (b) is _{CrO x -Ti 1 .83 O 4,} (c) the _{CoO x -Ti 1 .83 O 4,} ( d) is a _{NiO x -Ti 1.83 O 4, (} e) is _.83 O _x CuO -Ti ₁ and ₄ (f) shows a ZnO _x -Ti _{1 .83} O _4.

As shown in FIG. 10, it can be seen that various transition metal compounds may combine with the negatively charged and exfoliated titanium oxide of the present invention to form new hybrid compounds.

<Experiment 9> scanning electron microscope (SEM) measurement of the _{MO x -Ti 1 .83 O 4 (} M = Co, Ni, Cu and Zn)

The visible light responsive photocatalyst material of the present invention using various transition metal compounds was observed by electron emission microscope. The results are shown in FIG.

In each graph of FIG. 11 (a) is a _{CoO x -Ti 1 .83 O 4,} (b) is _{.83 O NiO x -Ti 1 4,} (c) is CuO _x -Ti _1.83 O ₄ and (d) ZnO _x -Ti _{1 .83} O represents a _{4, MO x -Ti 1.83 O 4} (M = Co, Ni, Cu and Zn), as shown in the picture is to form a stacked layer structure in a well is reunited after the separation You can check it.

Experimental Example 10 MO _x -Ti _{1 .83} O ₄ BET measurement of (M = Co, Ni, Cu and Zn)

The specific surface area was measured in the same manner as in Experimental Example 4, and the results are shown in FIG. 12.

As shown in Fig. _{12, MO x -Ti 1 .83 O} 4 All materials of (M = Co Ni, Cu and Zn) showed hysteresis. This suggests that all MO _x -Ti _{1 .83} O ₄ have a porous structure.

Claims (3)

A visible light responsive photocatalyst material represented by Formula 1 below:
<Formula 1>
Transition Metal-O _x -Ti _{2-y / 4} -O ₄
In Formula 1, x is a variable according to the type of transition metal, x is a number between 0.5 and 4.0, y is a number between 0.67 and 0.73. The visible light responsive photocatalyst material of claim 1, wherein y is 0.67. The visible light responsive photocatalyst material according to claim 1, wherein the transition metal is any one selected from the group consisting of Cr, Co, Ni, Cu, and Zn.

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