KR102130378B1 - Photocatalys and method for preparing the same - Google Patents

Abstract

The present invention relates to a photocatalyst and a product including the same. More particularly, the present invention relates to an inorganic oxide-based photocatalyst comprising: an inorganic oxide; and an iron oxide layer formed on the inorganic oxide, wherein the iron oxide layer includes at least one type of compounds represented by chemical formula 1: Fe_XO_YH_Z (X, Y and Z are each selected from 0 to 3, and X, Y and Z are not 0.) The iron oxide layer also has photoactivity in dry conditions of 30% or less of humidity.

Description

Photocatalyst and its manufacturing method{PHOTOCATALYS AND METHOD FOR PREPARING THE SAME}

The present invention relates to a photocatalyst having an expanded catalytically active wavelength region and a method for manufacturing the same.

The photocatalyst has catalytic activity by absorbing light energy and oxidatively decomposes environmental pollutants such as organic substances with strong oxidizing power by catalytic activity. That is, the photocatalyst, by irradiating light (ultraviolet rays) having energy of a band gap or more, a transition of electrons from a valence band to a conduction band occurs, and a hole is formed in the valence band. These electrons and holes diffuse to the surface of the powder, and react with oxygen and moisture to cause a redox reaction or recombine to generate heat. That is, electrons in the conduction band reduce oxygen to generate superoxidion ions, and holes in the valence band oxidize moisture to form hydroxy radicals (OH·). With the strong oxidizing power of hydroxy radicals (OH·) generated by these holes, it is possible to exhibit decomposition, sterilizing power, hydrophilicity, etc. of gaseous or liquid organic substances adsorbed on the surface of the photocatalyst, that is, difficultly decomposing organic substances. In general, titanium dioxide (TiO ₂ ) powder is used as a photocatalyst, and titanium dioxide (TiO ₂ ) has the advantages of being harmless to the human body, having excellent photocatalytic activity, excellent light corrosion resistance, and low price. Titanium dioxide (TiO ₂ ) absorbs and reacts with ultraviolet rays of 388 nm or less to generate electrons (conduction bands) and holes (valence bands). In this case, the ultraviolet rays used as light sources are lamps, incandescent lamps, and mercury lamps. Artificial lighting, light emitting diodes, and the like can be used. The electrons and holes generated in the reaction recombine in 10 ^-12 to 10 ^-9 seconds, but if contaminants or the like adsorb on the surface before recombination, they are decomposed by the electrons and holes. However, to obtain the band gap energy (wavelength of 380nm or more) of titanium dioxide (TiO ₂ ) powder in sunlight, since about 2% of the light can be used, smooth catalytic activity in the visible region (400~800nm), which is the main wavelength of sunlight Have difficulty having That is, in order to respond to visible light, it is essential to effectively reduce the band gap of the photocatalyst and to efficiently separate the electron/hole pairs generated through light absorption, but the efficiency of the visible light-sensitive photocatalyst of titanium dioxide (TiO ₂ ) powder is still It is not reaching the level to be commercialized in the air cleaning field.

The present invention is to solve the above-mentioned problems, the present invention is to provide an inorganic oxide-based photocatalyst, formed by introducing a ferrocene doping process, having excellent photocatalytic activity in the visible light region.

The present invention provides a composition for a photocatalyst comprising an inorganic oxide-based photocatalyst in the present invention.

The present invention is to provide a product comprising an inorganic oxide-based photocatalyst according to the present invention and having a photolysis function.

The present invention is to provide a method for producing an inorganic oxide-based photocatalyst according to the present invention using an organic metal compound doping process.

However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Inorganic oxide-based photocatalyst according to an aspect of the present invention, inorganic oxide; And an iron oxide layer formed on the inorganic oxide. The iron oxide layer includes one or more of the compounds represented by Chemical Formula 1 below, and has photoactivity under dry conditions of 30% or less humidity. .

[Formula 1]

Fe _x O _Y H _Z

(X, Y and Z are each selected from 0 to 3, and X, Y and Z are not 0.)

According to an embodiment of the present invention, the inorganic oxide is to include at least one selected from the group consisting of oxides containing at least one of Ti, Zn, Al, and Sn, the iron oxide layer has an iron content It may be 0.001 to 10% by weight relative to the inorganic oxide.

According to an embodiment of the present invention, the inorganic oxide includes at least one selected from the group consisting of beads, powder, rods, wires, needles, and fiber forms, and the size of the inorganic oxide is 1 nm to 500 μm. Can be.

According to an embodiment of the present invention, the inorganic oxide does not include an inorganic oxide including iron, and the iron oxide layer may be a ferrocene deposited on the inorganic oxide being heat-treated.

According to an embodiment of the present invention, the inorganic oxide does not contain an inorganic oxide containing iron, and the iron oxide layer is a ferrocene deposited on the inorganic oxide, heat-treated, in a visible light region of 400 nm or more. It may have a photoactive.

According to an embodiment of the present invention, the iron oxide layer may include iron oxide derived from ferrocene.

According to an embodiment of the present invention, the specific surface area of the inorganic oxide-based photocatalyst may be 5 (m ² /g) or more, and the average pore size may be 50 nm or less.

The product having a photodegradation function according to another aspect of the present invention includes an inorganic oxide-based photocatalyst according to an embodiment of the present invention; the inorganic oxide-based photocatalyst is coated on a substrate or the inorganic oxide-based photocatalyst It is a molded chain comprising a.

According to one embodiment, the product, paint, wallpaper, blinds, sidewalk block, median separator, artificial turf, artificial turf filler, elastic packaging material, flooring, asphalt, concrete, elastic mat, LED display, MMA (methyl metha acrylate) may be any one selected from the group consisting of paints, air purifiers, soundproof or sound absorbing walls, flooring materials, steel pipes and artificial trees for landscaping.

The present invention can provide an inorganic oxide-based photocatalyst having excellent photocatalytic activity in the visible light region and excellent photodecomposition efficiency in various humidity and temperature regions.

The present invention can provide an inorganic oxide-based photocatalyst in a simple and economical manner, and the inorganic oxide-based photocatalyst has the ability to decompose volatile organic compounds with high efficiency and excellent stability in response to light in the visible light region. It can be effectively applied as a material for indoor and outdoor air cleaning.

The present invention provides an inorganic oxide-based photocatalyst having excellent photocatalytic activity in a visible light region by a ferrocene doping process according to an embodiment, and the photocatalyst can be applied to construction materials, interior accessories, etc. that can add and utilize a photoactive function. have.

Specifically, the photocatalyst proposed in one embodiment of the present invention, lighting or display, such as LED, concrete for construction, tile, MMA (methyl metha acrylate) paint, air purifier, median or road guardrail, soundproof wall or sound absorbing wall, It can be applied to flooring materials such as indoor and outdoor sports stadiums, automobile interior materials, wallpaper or blinders, various materials including UV coating layers, steel pipes or waterproof materials, and artificial trees for landscaping.

1 is a flowchart of a method for manufacturing an inorganic oxide-based photocatalyst according to the present invention, according to an embodiment of the present invention.
Figure 2, according to an embodiment of the present invention, illustratively shows the configuration of a TR-CVD reactor used in the manufacturing process of the inorganic oxide-based photocatalyst according to the present invention.
Figure 3, according to an embodiment of the present invention, illustratively shows the manufacturing process of the inorganic oxide-based photocatalyst according to the present invention.
4 shows an image of an inorganic oxide-based photocatalyst prepared according to an embodiment of the present invention.
5 shows a TEM image of an inorganic oxide-based photocatalyst prepared according to an embodiment of the present invention.
6 shows the evaluation results of the photodegradation performance of the inorganic oxide-based photocatalyst prepared according to the embodiment of the present invention.
Figure 7 shows the evaluation results of the photodegradation performance according to the humidity of the inorganic oxide-based photocatalyst prepared according to an embodiment of the present invention.
Figure 8 shows the results of the stability evaluation of the photolysis performance according to the repeated photolysis experiments of the inorganic oxide-based photocatalyst prepared according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

Various modifications may be made to the embodiments described below. The examples described below are not intended to be limiting with respect to the embodiments, and should be understood to include all modifications, equivalents, or substitutes thereof.

The terms used in the examples are only used to describe specific examples, and are not intended to limit the examples. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “include” or “have” are intended to indicate that there are features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the embodiment belongs. Terms, such as those defined in a commonly used dictionary, should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that detailed descriptions of related well-known technologies may unnecessarily obscure the subject matter of the embodiments, detailed descriptions thereof will be omitted.

In addition, terms used in the present specification are terms used to appropriately represent a preferred embodiment of the present invention, which may vary depending on a user, an operator's intention, or a custom in the field to which the present invention pertains. Therefore, definitions of these terms should be made based on the contents throughout the present specification. The same reference numerals in each drawing denote the same members.

Throughout the specification, when one member is positioned “on” another member, this includes not only the case where one member abuts another member, but also the case where another member exists between the two members.

Throughout the specification, when a part “includes” a certain component, it means that the other component may be further included instead of excluding the other component.

Hereinafter, the inorganic oxide-based photocatalyst of the present invention will be described in detail with reference to examples and drawings. However, the present invention is not limited to these examples and drawings.

The present invention relates to an inorganic oxide-based photocatalyst, according to an embodiment of the present invention, the photocatalyst, the inorganic oxide-based photocatalyst according to an aspect of the present invention, an inorganic oxide; And an iron oxide layer formed on the inorganic oxide. The iron oxide layer includes one or more of the compounds represented by Chemical Formula 1 below, and has photoactivity under dry conditions of 30% or less humidity. .

[Formula 1]

Fe _x O _Y H _Z

(X, Y and Z are each selected from 0 to 3, and X, Y and Z are not 0.)

The inorganic oxide is an inorganic semiconductor compound that absorbs light energy and exhibits catalytic activity. For example, Ti, Zn, Al, Fe, W, Sn, Bi, Ta, Cu, Si, Ru, Sr, Ba, and Ce It is an oxide containing at least one selected from the group consisting of, it may be preferably Ti, Zn, Al and Sn. Specifically, TiO ₂ , Al ₂ O ₃ , ZnO ₂ , ZnO, SrTiO ₃ , Fe ₂ O ₃ , Ta ₂ O ₅ , WO ₃ , SnO ₂ , Bi ₂ O ₃ , NiO, Cu ₂ O, SiO, SiO ₂ , MoS ₂ , InPb, RuO ₂ , CeO _{2 and the} like. In addition, semiconductor compounds such as CdS, GaP, InP, GaAs, and InPb may be further included in addition to the oxide.

The inorganic oxide may include at least one selected from the group consisting of beads, powder, rod, wire, needle, and fiber, and the size of the inorganic oxide is 1 nm or more; 10 nm or more; 30 nm to 500 μm; 30 nm to 100 μm; Or 30 nm to 1 μm. The size may mean diameter, thickness, length, etc., depending on the shape.

As an example, the iron oxide layer may be formed by a ferrocene doping process. For example, the ferrocene layer formed on the inorganic oxide may be thermally decomposed to ferrocene, and may include iron oxide converted from ferrocene by the thermal decomposition process. The ferrocene doping process will be described in more detail in the following manufacturing method.

As an example, the ferrocene-derived iron oxide is an iron oxide derived from at least one of ferrocene and ferrocene derivatives, and the ferrocene derivative is ferrocene aldehyde, ferrocene ketone, ferrocene carboxylic acid, ferrocene alcohol, phenol or ether compound, nitrogen- Containing ferrocene compounds, sulfur-containing ferrocene compounds, phosphorus-containing ferrocene compounds, silicon-containing ferrocene compounds, 1,1'-di-copper ferrocene, ferrocene boric acid , Ferrocenyl cuprous acetylide and bisferrocenyl titanocene.

Iron content in the ferrocene-derived iron oxide layer is 0.001 to 10% by weight compared to the inorganic oxide; 0.01 to 10% by weight; 0.001 to 5% by weight; 0.01 to 3% by weight; 0.01 to 1.5% by weight; Or 0.01 to 1% by weight. When included in the above range, photocatalytic activity in the visible light region may be increased to improve photolysis efficiency. In addition, although the absorption of the visible region may increase when the iron content is increased, since the photocatalytic activity may be lowered due to the increase in the iron content, it is preferable to include the iron content within the above range, and more preferably, The content of iron may be 0.01 to 1% by weight.

The ferrocene derived iron oxide layer, 0.01 nm or more; 0.1 nm or more; 10 nm or more; Or it may have a thickness of 1 nm to 100 nm. When included in the thickness range, the porosity of the photocatalyst can be prevented due to an increase in the thickness of the coating layer, and the amount of adsorption of moisture, OH-ions, decomposition targets, etc. on the surface can be increased to improve photodegradation performance. In addition, the ferrocene-derived iron oxide layer, 0.01 nm or more; 0.1 nm or more; 10 nm or more; Or it may include ferrocene-derived iron oxide having a size of 1 nm to 100 nm. The size may mean length, diameter, thickness, and the like depending on the shape.

The ferrocene-derived iron oxide may include one or more of the compounds represented by Formula 1 below.

[Formula 1]

Fe _x O _Y H _Z

Here, X, Y and Z are each selected from 0 to 3, and X and Y are not 0. That is, by absorbing light in the visible region and introducing a stable and inexpensive semiconducting material, iron oxide (Fe _x O _y H _z ), in the form of nano-sized particles to the TiO ₂ surface to form a photocatalyst that responds to visible rays. Can.

According to an embodiment, not only the X and Y, but also the Z may not be 0.

According to an embodiment of the present invention, the inorganic oxide-based photocatalyst, the wavelength region exhibiting a photoreaction by absorbing light is extended from ultraviolet to visible light region, and particularly, can exhibit excellent photocatalytic activity in a visible light region of 400 nm or more. . In addition, the photocatalytic reactivity capable of adsorption and decomposition of the decomposition target on the surface is improved to have photocatalytic activity in various humidity regions, and can exhibit excellent photocatalytic activity even in dry conditions of 30% or less humidity.

According to an embodiment of the present invention, the inorganic oxide-based photocatalyst, 5 (m ² /g) or more; 5 (m ² /g) to 1000 (m ² /g); Or it has a specific surface area of 5 (m ² /g) to 100 (m ² /g), and the average pore size may be 50 nm or less. That is, by introducing ferrocene-derived iron oxide on the surface, the adsorption amount of the decomposition target is increased on the surface of the photocatalyst, and the photocatalytic reactivity is increased to improve the efficiency of the photocatalyst.

According to an embodiment of the present invention, the inorganic oxide-based photocatalyst is applied to the decomposition of various harmful substances, that is, it can be used for treatment of environmental pollutants, odor substances, organic compounds, acid gases, and the like. For example, it is used for adsorption and/or photolysis of at least one of gas, liquid, and solid materials, and may exhibit photoactivity by light energy including various light rays such as halogen lamps, xenon lamps, sunlight, and light emitting diodes. More specifically, as the gas, VOCs (volatile organic compounds) such as acidic, basic gas, acetaldehyde, ketones, hydrocarbons of aromatic hydrocarbons and aliphatic hydrocarbons (Paraffin-based and Olefin-based), ozone gas, organic And inorganic glass gas, and more specifically, carbon dioxide, carbon monoxide, NOx, SOx, HCl, HF, NH ₃ , methylamine, formaldehyde, hydrogen sulfide, amine, methylmergaptan, hydrogen, oxygen, nitrogen, methane, paraffin , Olefin, and the like. Examples of the liquid include formaldehyde, acetaldehyde, benzene, toluene, methyl ethyl ethyl ketone (MEK), trichloroethylene, disinfectant, gasoline, diesel, oil, alcohol, Phenol, dye, and the like, and the solid may be a transition metal, a precious metal such as Pt, Pd, ions and/or particles such as Hg, Cr, nanoparticles of 100 nm or less, but is not limited thereto.

According to an embodiment of the present invention, the inorganic oxide-based photocatalyst according to the present invention; It relates to a photocatalyst composition comprising a.

The inorganic oxide-based photocatalyst may be included in 0.01 to 99% by weight of the photocatalyst composition.

The photocatalyst composition may include an aqueous solvent, an oily solvent, or both in a residual amount, and may be appropriately selected depending on the application field. For example, it may be a lower alcohol of C ₁ -C ₄ such as water, tanol, ethanol, propanol, isopropanol, butanol, but is not limited thereto.

The photocatalyst composition, if it does not deviate from the object of the present invention, may further include additives according to performance improvement and application fields, and may further include a surfactant, a siloxane-based binder, an antibacterial agent, a disinfectant, etc. It is not mentioned.

The photocatalyst composition may be coated on a substrate or molded into various shapes. For example, the substrate may include cellulose paper; Synthetic wood, wood; fiber; textile; And metal, polymer resin or glass, powder of glass, sheet, film or beads; It may include one or more selected from the group consisting of, but is not limited thereto. In addition, the substrate may be a finished product that requires a photocatalytic function, for example, lamps, TVs, refrigerators, laptops, household appliances, wallpaper, concrete, blinders, furniture, tiles, mats, interior accessories, construction materials, etc., but is not limited thereto. Does not work.

According to an embodiment of the present invention, the inorganic oxide-based photocatalyst according to the present invention; It relates to a product having a photocatalytic function, including. In addition to the photocatalytic function, the product can also exhibit air purification function. For example, it may be one having a photodegradation function and/or an air purification function by photoactivity such as volatile substances, odor substances, and contaminants.

According to an embodiment of the present invention, the product may be a molded body comprising the photocatalyst or the photocatalyst bound on a substrate.

For example, it may be a substrate coated with a photocatalyst or photocatalyst composition, an impregnated substrate, a molded substrate, a solid comprising a photocatalyst or photocatalyst composition, a liquid, or a formulation comprising both, and the like. The molding method may be molded by mixing the photocatalyst and photocatalyst composition according to the present invention with a molding material, or by injecting together the injection molding of the molding material.

For example, the formulation may be a powder, solid, suspension, emulsion, cream, ointment, gel, liquid formulation, etc., but may be, for example, ink, paint, or dye, but is not limited thereto.

For example, the products include masks, helmets, gas masks, anti-respirator clothing, firefighting clothing, pharmaceuticals, cosmetics, sensors, semiconductors, lithium batteries, solar cells, boilers, cell phones, laptops, PCs, refrigerators, air conditioners, heaters, Electric appliances such as electric floors, microwave ovens, kitchen appliances such as gas ranges, gas ovens, kettles, cutlery, tableware, furniture such as beds, wardrobes, accessories such as necklaces, ink, paint (water-based, oil-based), paints, dyes Used for dyes, artificial turf, artificial turf filling, elastic packaging, flooring, asphalt, concrete, elastic packing materials for children's play facilities, sidewalk blocks, median, concrete, glass, insulation sheets, wallpaper, blinds, windows, mats, elastic Interior or building materials such as mats, yoga mats, tiles, incandescent or led bulbs, lighting devices or appliances such as stands, air conditioning filters, dehumidifier filters, air cleaner filters, etc., materials for air purification, thermometers, syringes, stethoscopes, diagnostics It may be applied to kits or patches, medical equipment such as patient clothes, and clothing, but is not limited thereto.

Preferably, it may be a building material for air purification, such as paint, wallpaper, blind, sidewalk block, median separator, artificial turf, artificial turf filler, elastic packaging material, flooring, asphalt, concrete, elastic mat, and the like.

According to one embodiment, the product, paint, wallpaper, blinds, sidewalk block, median separator, artificial turf, artificial turf filler, elastic packaging material, flooring, asphalt, concrete, elastic mat, LED display, MMA (methyl metha acrylate) may be any one selected from the group consisting of paints, air purifiers, soundproof or sound absorbing walls, flooring materials, steel pipes and artificial trees for landscaping.

The present invention relates to a method of manufacturing an inorganic oxide-based photocatalyst, according to an embodiment of the present invention, the manufacturing method comprises: preparing an inorganic oxide; Forming a ferrocene layer on the inorganic oxide; And forming a ferrocene-derived iron oxide layer by heat treatment after the step of forming the ferrocene layer.

The preparing of the inorganic oxide is a step of preparing an inorganic oxide dispersion or coating an inorganic oxide on a substrate, wherein the dispersion is an aqueous solvent, an oily solvent, or a mixture of the two, and the substrate is a silicon substrate , A wafer, a glass substrate, a semiconductor substrate, a metal substrate, and the like. The inorganic oxide may be applied by spin coating, roll coating, spray coating, dip coating, flow coating, doctor blade method, or the like.

In the forming of the ferrocene layer, a ferrocene film may be formed using a wet coating method, a sputtering method, or a vapor deposition method. Preferably, a deposition method such as atomic layer deposition (ALD) or temperature-regulated chemical vapor deposition (CVD) is used, and more preferably, TR-CVD (temperature-regulated chemical vapor deposition) is used. A ferrocene layer can be formed. When the TR-CVD is applied, the amount of iron oxide deposited on the inorganic oxide can be easily controlled by controlling the amount of ferrocene, and the manufacturing process of the photocatalyst can be simplified and the photocatalyst can be efficiently provided.

The step of forming the ferrocene layer is performed at room temperature to 120°C, preferably 40°C to 100°C; More preferably it can be carried out at 60 ℃ to 100 ℃. That is, it may be carried out at 60 ℃ to 100 ℃ in order to induce the deposition by the vaporization process of ferrocene when applying TR-CVD.

The step of forming the ferrocene layer is performed in an air or oxygen atmosphere under atmospheric conditions, and may further include an inert gas.

In the step of forming the ferrocene layer, the ferrocene layer containing ferrocene of 0.01% to 20% by weight of the inorganic oxide may be formed.

According to an embodiment of the present invention, the step of forming the ferrocene-derived iron oxide layer may partially or completely oxidize with iron oxide through heat treatment of the ferrocene layer, and remove impurities such as carbon residues.

The forming of the ferrocene-derived iron oxide layer may include: 50°C to 900°C; Alternatively 100°C to 800°C; Heat treatment may be performed at two or more stages at a temperature.

For example, the step of forming the ferrocene-derived iron oxide layer includes a first heat treatment at a temperature of 100°C to 300°C and a second heat treatment at a temperature of 300°C to 900°C, and each step is different from each other. It can be heat treated at a temperature. Each of the above steps is performed for 1 minute to 20 hours, respectively, and air, 20% or more; It can be carried out in an air or inert gas atmosphere containing at least 40% oxygen.

That is, the first heat treatment step may be an annealing process for iron oxide deposition, which is converted to iron oxide by the reaction of ferrocene and oxygen. The second heat treatment step is a post-heat treatment step after the first heat treatment step, and may be an annealing process to improve the activity and performance of the photocatalyst by removing impurities such as carbides.

Hereinafter, the present invention will be described in more detail by examples and comparative examples.

However, the following examples are only for illustrating the present invention, and the contents of the present invention are not limited to the following examples.

Example 1

A photocatalyst (Fe-TiO ₂ ) in which nano-sized iron oxide particles are deposited on TiO ₂ is prepared using the TR-CVD (temperature-controlled chemical vapor deposition) reactor of FIG. ₂ and utilizing the temperature-controlled chemical vapor deposition method shown in FIG. 3. Did. More specifically, 0.02 g of ferrocene, a precursor of iron, is placed in a container made of quartz on the inner bottom of a reactor made of stainless steel surrounded by a heating band. After placing 3 g of TiO ₂ (TiO ₂ , P-25, Evonik, particle size: 25 nm) in a container made of stainless steel wire in the center inside the reactor, the reactor is sealed with polyimide tape. The temperature of the reactor was carried out by a TR-CVD vaporization process at 60° C. for 2 hours, and then a ferrocene deposition process was performed, and the temperature was raised to 200° C. and maintained for 12 hours to convert to iron oxide.

Then prepare a final iron oxide -TiO ₂ hybrid photocatalytic nano-structure (or, expressed as Fe-TiO ₂₎ by an additional heat treatment for 2 hours at 750 ℃ in dry air gas atmosphere to remove the TiO _2. The content of iron deposited on TiO ₂ under these conditions is about 0.09 wt%.

Example 2

An iron oxide-TiO ₂ hybrid nanostructured photocatalyst was prepared in the same manner as in Example 1 except that 0.05 g of the iron precursor Ferrocene was applied. The iron content deposited on TiO ₂ under the conditions is about 0.13 wt%.

Example 3

An iron oxide-TiO ₂ hybrid nanostructured photocatalyst was prepared in the same manner as in Example 1, except that 0.1 g of the iron precursor Ferrocene was applied. The iron content deposited on TiO ₂ under the conditions is about 0.65 wt%.

Example 4

An iron oxide-TiO ₂ hybrid nanostructured photocatalyst was prepared in the same manner as in Example 1, except that 0.3 g of the iron precursor Ferrocene was applied. The content of iron deposited on TiO ₂ under these conditions is about 1.81 wt%.

The prepared photocatalyst (Fe-TiO ₂ ) is compared to a TiO ₂ photocatalyst coated with a general iron oxide, and the transparency and color are shown in FIG. 4. 4, the photocatalyst (Fe-TiO ₂ ) coated with ferrocene-derived iron oxide according to the present invention is more transparent and lighter than the photocatalyst (Fe ₂ O ₃ -TiO ₂ ) coated with iron oxide (Fe ₂ O ₃ ). It can be seen that it has a yellow color.

The TEM image (image measured with a transmission electron microscope) of the prepared photocatalyst (Fe-TiO ₂ ) was measured and shown in FIG. 5. In FIG. 5, as the iron content decreased, the size of the iron oxide particles deposited on the Fe-TiO ₂ surface decreased.

The specific surface area (BET) and BJH average pore size through the nitrogen adsorption analysis of the prepared photocatalyst (Fe-TiO ₂ ) are measured and are shown in Table 1.

0.13 wt% Fe-TiO ₂ 0.65 wt% Fe-TiO2 1.81 wt% Fe-TiO ₂ BET Surface area(m ² /g) 11.6259 10.3426 8.3939 BJHAdsorption average pore size(nm) 13.2 12.5 13.9

Looking at Table 1, it can be seen that even when the iron content of Fe-TiO ₂ is changed, the specific surface area and the average pore size do not change significantly, and the mesopores of Fe-TiO ₂ are formed.

Evaluation Example 1

Put the photocatalyst (Fe-TiO ₂ ) of Example 1 in a volume 5.3 L reactor composed of quartz glass on the top surface, acetaldehyde initial concentration 66 ppm, dry air (relative humidity: ~33%, total pressure 760 torr) and the visible light region with white LED at room temperature to analyze the photodegradation properties of acetaldehyde. Acetaldehyde in the reactor was measured by gas chromatography. The results are shown in FIG. 6.

FIG. 6 is a graph showing (a) acetaldehyde mole number change over time of visible light (white light) irradiation at 33% humidity condition, and (b) carbon dioxide mole number change as a result of photodecomposition reaction of acetaldehyde. Looking at it, the photocatalyst (Fe-TiO ₂ ) prepared in Example can be confirmed that photodecomposition of acetaldehyde is performed by photocatalytic activity by visible light (white light) irradiation, and the ferrocene deposition amount is 0.09 wt% and decomposition efficiency in visible light You can see this is the biggest. In addition, it can be seen that the smaller the iron content, the faster the photodecomposition rate of acetaldehyde of Fe-TiO ₂ .

Evaluation Example 2

The photocatalyst (Fe-TiO ₂ ) having a ferrocene deposition amount of 0.13 wt% was analyzed for the photodegradation properties of acetaldehyde in the same manner as in Evaluation Example 1 under dry conditions without humidity and relative humidity: ~33%. Acetaldehyde and carbon dioxide in the reactor were periodically measured using gas chromatography. The results are shown in FIGS. 7 and 8.

FIG. 7 shows that (a) changes in the number of moles of acetaldehyde and (b) changes in the number of carbon dioxide generated as a result of the photolysis reaction of acetaldehyde according to the time of visible light irradiation, when the acetaldehyde photolysis experiment under dry conditions and 33% humidity was performed. 7, the slopes of the two graphs are similar in the same acetaldehyde concentration section indicated by a dotted line, and shows that acetaldehyde photolysis activity is maintained similarly in visible light irrespective of the presence or absence of humidity.

In addition, it can be confirmed that the carbon dioxide generation increases with the light irradiation time, which is generated by the complete oxidation of acetaldehyde.

FIG. 8 shows changes in the number of moles of (a) acetaldehyde and (b) the number of moles of carbon dioxide generated as a result of the photodecomposition reaction of acetaldehyde according to visible light irradiation time, when repeatedly used in the acetaldehyde photolysis experiment under a 33% humidity condition. It is a graph shown, and it can be seen from FIG. 8 that high photocatalytic activity is maintained even in a repeated photolysis experiment.

Overall, the present invention, TiO ₂ (hereinafter Fe-TiO ₂ ) on which iron oxide is deposited, was utilized for photodegradation experiments of acetaldehyde, which is one of the representative volatile organic compounds, and acetaldehyde photodegradation activity of Fe-TiO ₂ according to the content of iron oxide Compared. As a result, when the iron content was as low as about 0.09 wt%, the photodegradation activity of acetaldehyde of Fe-TiO ₂ was the highest, and about 70% of the initial acetaldehyde concentration (~95 mol ppm) decreased within 20 hours. In addition, in general, the activity of the photocatalyst is greatly affected by humidity, but Fe-TiO ₂ prepared in the present invention shows similar catalytic activity under dry conditions and humidity conditions, confirming that the photocatalytic activity is not sensitive to humidity. As a result of nitrogen adsorption experiments of Fe-TiO ₂ having various iron contents, it was confirmed that the iron content did not significantly affect the total specific surface area of the photocatalyst. In addition, considering that the photocatalytic activity of Fe-TiO ₂ was greatly affected by the iron content, it can be seen that the photocatalytic activity is more important in the electronic structure of the interface between the deposited iron oxide nanoparticles and TiO ₂ than the surface structure. . In addition, it was confirmed through a transmission electron microscope that the smaller the iron content, the smaller the size of the iron oxide particles present on the surface. When 1~3 nanometer-level iron oxide particles were deposited, the photocatalytic activity may be increased. Based on the results of the analysis, Fe-TiO ₂ absorbs light in the visible region when the iron oxide nanoparticles of a very small size have a content of about 0.09 wt%, and the electron/hole pairs are most efficiently separated, and oxygen/ It can react with water to form radicals, which can rapidly break down acetaldehyde. On the other hand, if the target organic material is not completely oxidized and partially oxidized and remains on the surface of the photocatalyst to block the active site, the activity of the photocatalyst decreases, which has been pointed out as one of the biggest problems of the photocatalyst. However, the Fe-TiO ₂ prepared in the present invention maintained the same catalytic activity even in repeated acetaldehyde photolysis experiments, and thus it was confirmed that there was no problem of catalytic activity degradation.

As described above, although the embodiments have been described by a limited embodiment and drawings, those skilled in the art can make various modifications and variations from the above description. For example, even if the described techniques are performed in a different order than the described method, and/or the described components are combined or combined in a different form from the described method, or replaced or replaced by another component or equivalent Appropriate results can be achieved. Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (10)

Inorganic oxides; And
An iron oxide layer formed on the inorganic oxide;
Including,
The iron oxide layer is to include one or more of the compounds represented by the formula (1),
The size of the inorganic oxide is 1 nm to 500 μm,
The specific surface area of the inorganic oxide-based photocatalyst is 5 (m ² /g) or more, and the average pore size is 50 nm or less,
It has a photoactivity even in dry conditions of 0% RH,
Inorganic oxide based photocatalyst.
[Formula 1]
Fe _x O _Y H _Z
(X, Y and Z are each selected from 0 to 3, and X, Y and Z are not 0.)
According to claim 1,
The inorganic oxide is to include at least one selected from the group consisting of oxides containing at least one of Ti, Zn, Al and Sn,
The iron oxide layer has an iron content of 0.001 to 10% by weight compared to the inorganic oxide,
Inorganic oxide based photocatalyst.
According to claim 1,
The inorganic oxide is to include at least one selected from the group consisting of beads, powder, rod, wire, needle and fiber form,
Inorganic oxide based photocatalyst.
According to claim 1,
The inorganic oxide does not contain an inorganic oxide containing iron,
In the iron oxide layer, ferrocene deposited on the inorganic oxide is heat-treated,
Inorganic oxide based photocatalyst.
According to claim 1,
The inorganic oxide does not contain an inorganic oxide containing iron,
In the iron oxide layer, ferrocene deposited on the inorganic oxide is heat-treated,
It has a photoactivity in the visible light region of 400 nm or more,
Inorganic oxide based photocatalyst.
According to claim 1,
The iron oxide layer is to include iron oxide derived from ferrocene,
Inorganic oxide based photocatalyst.
delete Including the inorganic oxide-based photocatalyst of claim 1;
The photocatalyst is to be included in 0.01 to 99% by weight of the photocatalyst composition,
Photocatalyst composition.
Including the inorganic oxide-based photocatalyst of claim 1;
The inorganic oxide-based photocatalyst is coated on a substrate or is a molded body comprising the inorganic oxide-based photocatalyst,
Photodegradable,
product.
The method of claim 9,
The products include paint, wallpaper, blinds, sidewalk blocks, median separator, artificial turf, artificial turf filler, elastic packaging, flooring, asphalt, concrete, elastic mat, display including LED, MMA (methyl metha acrylate) paint, air Purifier, soundproofing wall, sound absorbing wall, flooring, steel pipe, and any one selected from the group consisting of artificial trees for landscaping,
product.

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