KR20130045911A - Method for producing photocatalyst coating film, and photocatalyst coating film - Google Patents

Abstract

An object of the present invention is to realize a high production yield of an iron-supported titanium dioxide film. To achieve this purpose, a water slurry obtained by mixing titanium dioxide powder and an aqueous iron chloride solution is produced, and the resulting water slurry is sprayed by a thermal spraying technique. Since the photocatalyst film can be formed while FeO (OH) is supported on the titanium dioxide powder at the time of thermal spraying, a significant improvement in production yield is realized.

Description

Manufacturing Method of Photocatalytic Film and Photocatalytic Film {METHOD FOR PRODUCING PHOTOCATALYST COATING FILM, AND PHOTOCATALYST COATING FILM}

The present invention relates to a method for producing a photocatalytic coating and a photocatalytic coating. Specifically, the present invention relates to a method for producing a photocatalytic coating and a photocatalytic coating including a photocatalytic function capable of decontamination, antibacterial and sterilization of contaminants.

As the aging society progresses, the proportion of elderly people with reduced immunity accounts for the entire population, and thus strengthens hygiene management at medical sites, food production and processing sites in terms of prevention of infections and food poisoning. Is an urgent task. Various antimicrobial products have been developed on the basis of this social background, and in recent years, the use of the photocatalytic function in the antimicrobial processing has received particular attention.

Here, the term "photocatalytic function" refers to a catalytic material that is excited when light energy larger than the band gap energy of the conduction and valence bands is irradiated, and generates an electron-hole band to cause oxidation and reduction reactions. Optical semiconductor material).

Among the photocatalysts, photocatalysts using titanium dioxide (TiO ₂ ), that is, titanium dioxide particles having a rutile type crystal structure, are inexpensive, have excellent chemical stability, and have high catalytic activity. At the same time, it can decompose harmful substances such as endotoxin, a cell wall outer wall component of Gram-negative bacteria, and toxins produced by bacteria (for example, vero toxin produced by Escherichia coli), and the photocatalyst itself is harmless to the human body. Have

Therefore, research and application of the photocatalyst using titanium dioxide are advanced, and the titanium dioxide photocatalyst is widely used for antimicrobial processing of food containers, building materials, etc. (for example, refer patent document 1 and patent document 2). ).

In addition, since titanium dioxide expresses photocatalytic activity only under ultraviolet irradiation, sufficient catalytic activity cannot be expressed under room light containing almost no ultraviolet component. Therefore, there is known a technique for expressing photocatalytic activity under visible light irradiation by supporting a metal complex such as iron or a metal complex such as FeCl ₃ or a metal salt, that is, an iron compound, on titanium dioxide.

However, conventionally, when producing a photocatalytic coating that exhibits photocatalytic activity under visible light irradiation, a photocatalyst composition containing titanium dioxide powder carrying a sensitizer is dispersed, for example, in a paint or the like, and the coating is applied to the surface of a building material as an object. To produce a photocatalytic coating.

Specifically, for example, titanium dioxide (TiO ₂ ) is immersed in an aqueous solution of iron chloride (FeCl ₃ ) serving as a sensitizer and stirred, and iron or iron compound is supported on titanium dioxide, and iron The photocatalyst composition of titanium dioxide on which an iron compound was supported was made, and then the photocatalyst composition was dispersed in a coating material and coated on the surface of a building material or the like (see Patent Document 3, for example).

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-51263 Patent Document 2: Japanese Patent Application Laid-Open No. 2006-346651 Patent Document 3: Japanese Patent Application Laid-Open No. 2007-090336

However, a photocatalyst composition in which an iron compound is supported on titanium dioxide requires a very long time for its treatment and manufacturing process, and aims to realize quality improvement, cost reduction, or stabilization thereof by shortening the manufacturing process.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object thereof is to provide a method for producing a photocatalytic coating and a photocatalytic coating which can shorten the manufacturing process, stabilize the quality, and reduce the cost.

In order to achieve the above object, the method for producing a photocatalytic coating according to the present invention is a slurry containing at least one compound selected from photocatalytic particles, a water-soluble metal complex of Fe, Cu, Cr, Ni, or a water-soluble metal salt, and water. And a slurry of at least one type of Fe, Cu, Cr, Ni hydroxide, oxyhydroxide or oxide produced by thermally spraying the slurry and metal ions of the at least one kind of the compound react with water. And supporting the photocatalyst particles in the same manner and laminating the photocatalyst particles on the object.

Here, a slurry containing photocatalyst particles, water-soluble metal complexes of Fe, Cu, Cr, Ni or at least one compound selected from water-soluble metal salts, and water is formed, and the slurry is sprayed to form Fe, Cu, Cr, Water soluble metal complexes of Ni or metal ions of water soluble metal salts react with water to produce nano sized very fine Fe, Cu, Cr, Ni hydroxides, oxyoxides or oxides, and these hydroxides, oxyoxides or oxides surface the photocatalytic particles Evenly distributed and supported on.

Further, by spraying the slurry, at least one type of Fe, Cu, Cr, Ni hydroxide, oxyhydroxide or oxide formed by the reaction of the metal ion of the at least one compound with water is supported on the photocatalytic particles in the slurry. At the same time, by stacking the photocatalyst particles on the object, that is, at least one type of hydroxide, oxyhydroxide or oxide of Fe, Cu, Cr, and Ni before the photocatalyst particles are laminated on the object, the photocatalyst particles are not supported. By spraying the slurry, nano sized very fine Fe, Cu, Cr, Ni hydroxides, oxyoxides or oxides are dispersed and supported on the surface of the photocatalytic particles, which greatly shortens the manufacturing process and stabilizes the performance and quality of the photocatalytic functional film. can do.

Moreover, as "a water-soluble metal complex of Fe, Cu, Cr, and Ni", for example, [Cu (NH ₃ ) ₄ ] ²⁺ , [Fe (CN) ₆ ] ^4- , [Fe (CN) ₆ )] ^{3 -} , C ₁₀ H ₁₂ FeN ₂ O ₈ , and the like. Examples of the "water-soluble metal salt of Fe, Cu, Cr, and Ni" include FeCl ₃ , Fe ₂ (SO ₄ ) ₃ , and Fe (NO ₃ ). ₃ , CuSO ₄ , Cu (NO ₃ ) ₂ , CuCl ₂ , Ni (NO ₃ ) ₂ , NiCl ₂ , NiSO ₄ , Cr (NO ₃ ) ₃ , and the like.

Moreover, as "the hydroxide, oxy oxide, or oxide of Fe, Cu, Cr, Ni produced by the reaction of water-soluble metal complexes of Fe, Cu, Cr, and Ni with water", for example, CuO, Cu (OH) ₂ , FeO (OH), Fe (OH) _3, etc. are mentioned, As "the oxide of Fe, Cu, Cr, Ni, oxyoxide, or oxide which the metal salt of Fe, Cu, Cr, Ni reacts with water," For example, FeO (OH), Fe (OH) ₃ , Cu (OH) ₂ , CuO, Ni (OH) ₂ , NiO (OH), Cr (OH) ₃ , Cr ₂ O (OH) ₄ , Cr ₂ O ₃ have.

In addition, since the thermal spray frame approaches the vacuum state at high speed during the thermal spraying process, the metal ion of Fe, Cu, Cr, and Ni water-soluble metal complexes or water-soluble metal salts reacts with water in the slurry and oxygen in the air to form hydroxide, oxy It is considered to be an oxide or an oxide, and anions such as chlorine ions and nitrate ions are thought to volatilize by thermal spraying and diffuse into the atmosphere.

Here, when the hydroxide, oxyhydroxide or oxide of Fe, Cu, Cr or Ni exhibits a visible light response function, the hydroxide, oxyhydroxide or oxide of Fe, Cu, Cr or Ni supported under visible light irradiation is excited, As the electrons move toward the photocatalyst particles, oxidation reactions occur on the surface of Fe, Cu, Cr, Ni hydroxide, oxyhydroxide or oxide, and reduction reactions occur on the surface of the photocatalyst particles, resulting in the visible light responsiveness (see FIG. 1 (A)). .

Also, Fe, Cu, Cr, Ni hydroxide, oxy hydroxide or oxide exhibiting a visible light response function FeO (OH), Fe (OH) ₃ , Cu (OH) ₂ , CuO, Ni (OH) ₂ , NiO ( OH), Cr (OH) ₃ , Cr ₂ O (OH) ₄ , Cr ₂ O ₃ , and the like.

In addition, when Fe, Cu, Cr, Ni hydroxide, oxyhydroxide, or oxide exhibits a promoter function, photocatalytic particles are excited under ultraviolet irradiation, and excitation electrons are Fe, Cu, Cr, Ni hydroxide, oxyhydroxide or By moving to the oxide side, an oxidation reaction occurs on the surface of the photocatalytic particles, a reduction reaction occurs on a hydroxide, oxyhydroxide, or oxide surface of Fe, Cu, Cr, and Ni, and the photocatalytic performance is improved by charge separation (see FIG. 1 (B)).

Further, as Fe, Cu, Cr, hydroxides, oxy-oxide or an oxide of Ni represents the promoter function, it may be mentioned Fe ₂ O _3, CuO, NiO and the like.

In addition, the method for producing a photocatalytic coating according to the present invention comprises the steps of forming a slurry comprising a photocatalyst particle and at least one compound selected from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, and Ni and water; And spraying the slurry to laminate the photocatalyst particles contained in the slurry on the object.

Here, a slurry containing photocatalyst particles, water-soluble metal complexes of Fe, Cu, Cr, Ni or at least one compound selected from water-soluble metal salts, and water is formed, and the slurry is sprayed to form Fe, Cu, Cr, A water soluble metal complex of Ni or a metal ion of a water soluble metal salt reacts with water to produce nano sized very fine Fe, Cu, Cr, Ni hydroxides, oxyoxides or oxides, and these hydroxides, oxyoxides or oxides surface the photocatalytic particles Evenly distributed and supported on.

Further, by spraying the slurry and laminating the photocatalytic particles contained in the slurry to the object, that is, before depositing the photocatalytic particles on the object, at least one kind of hydroxide, oxyhydroxide, or oxide of Fe, Cu, Cr, and Ni in advance By spraying the slurry without supporting the form on the photocatalyst particles, nano sized very fine Fe, Cu, Cr, Ni hydroxides, oxyoxides or oxides are dispersed and supported on the surface of the photocatalyst particles, and greatly shorten the manufacturing process and the photocatalytic function coating. Stabilization of performance and quality can be achieved.

In addition, antibacterial metals (including at least one of silver, copper, zinc, aluminum, nickel, cobalt, or chromium metals) in the slurry containing photocatalyst particles such as titanium dioxide, antibacterial Selecting antimicrobial metals or antimicrobial metal complexes from metals, metal salts, metal complexes, oxyhydroxides, hydroxides or oxides together with photocatalyst particles by thermally spraying slurries containing metal salts or antimicrobial metal complexes and antimicrobial metals, antimicrobial metal salts or antimicrobial metal complexes. It can be laminated in at least one kind of form, and can produce a photocatalytic functional film containing a strong antibacterial action.

In addition, by adding a pigment to a slurry containing photocatalytic particles, such as titanium dioxide, and by spraying a slurry containing the photocatalyst particles and the pigment together, photocatalyst particles including the pigment can be laminated to produce a colorful and highly designable photocatalytic coating. can do.

In addition, an adsorbent (for example, zeolite, etc.) is added to a slurry containing photocatalyst particles such as titanium dioxide, and the adsorbent can be laminated together with the photocatalyst particles by spraying a slurry containing both the photocatalyst particles and the adsorbent. A photocatalyst film having a gas adsorption function can be produced.

Moreover, in order to achieve the said objective, the photocatalyst film which concerns on this invention forms the slurry containing a photocatalyst particle, at least 1 sort (s) of compound chosen from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, Ni, and water. And spraying the slurry to form at least one type of Fe, Cu, Cr, Ni hydroxide, oxyhydroxide or oxide produced by the reaction of metal ions of at least one kind of the compound with water to the photocatalytic particles in the slurry. At the same time as supporting, the photocatalyst particles were laminated on the object to prepare.

Moreover, the photocatalyst film which concerns on this invention forms the slurry containing a photocatalyst particle, at least 1 sort (s) of compound chosen from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, Ni, and water, and spraying the said slurry. It was prepared by laminating the photocatalyst particles contained in the slurry to the object.

Examples of the object for laminating photocatalyst particles include tiles, sanitary ware, glass, mirrors, concrete building materials, resin building materials, metal building materials, resin films, metal fibers, glass fibers, carbon fibers, and filters using these fibers. Can be.

In the method for producing a photocatalytic coating to which the present invention is applied, since the photocatalytic coating can be produced by a greatly shortened manufacturing process, there is little irregularity in the quality and performance of the coating, and high quality and production yield can be realized. In addition, high quality can also be realized with respect to the photocatalytic coating to which the present invention is applied.

Fig. 1A is a schematic diagram for explaining the visible light response function.
1B is a schematic diagram for explaining the promoter function.
It is a schematic diagram for demonstrating a thermal spraying value.
3 is an analysis result of the crystal structure using the XRD of the photocatalyst coating obtained by the method for producing a photocatalyst coating according to the present invention.
4 is a result of analyzing a crystal structure using XRD of a photocatalyst film obtained by a conventional method for producing a photocatalyst film.
Fig. 5 shows the results of analysis of the crystal structure using XRD of the photocatalyst film obtained by supporting iron after film formation of the titanium dioxide film.
6 is a conceptual diagram of a test evaluation method of a gas decomposition performance test of a photocatalyst coating.
7 shows the acetaldehyde gas decomposition test result (1).
Fig. 8 shows acetaldehyde gas decomposition test results (2).
9 is a conceptual diagram of a test method for evaluating the bactericidal effect of a photocatalytic coating.
10 shows evaluation test results of the bactericidal effect of the photocatalytic coating.
11 is a result of acetaldehyde gas decomposition test of the photocatalyst coating to which the present invention is applied.
12 shows E. coli sterilization test results of the photocatalyst coating to which the present invention is applied.
Fig. 13 shows the results of analysis of the crystal structure by XRD of the photocatalyst film on which the pigment is supported.
Fig. 14 shows the results of analysis of the crystal structure using XRD of the photocatalytic film obtained by the exclusive supporting method.
15 is an analysis result of a crystal structure using XRD of a photocatalyst film obtained by a backing method.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "embodiment" hereafter) for implementing invention is demonstrated, referring drawings.

<1. About iron support>

As an example of the manufacturing method of the photocatalyst coating which applied this invention, it consists of two processes of (1) water slurry production | generation process, and (2) thermal sprayed coating formation process. Hereinafter, each process is explained in full detail.

[One. Water slurry generation process]

As an example of the method for producing a photocatalytic coating to which the present invention is applied, the titanium dioxide powder and the Ti component of the titanium dioxide powder (TiO ₂ ) and the Fe component of the aqueous iron chloride solution (FeCl ₃ ) are Ti: Fe = 99: 1 in weight ratio. A water slurry (concentration 30% by weight) using an aqueous solution of iron chloride was produced.

Specifically, a water slurry using a rutile titanium dioxide powder having a particle diameter of about 30 nm and an aqueous iron chloride solution is produced. In the water slurry, rutile titanium dioxide powder was aggregated to form a particle diameter of about 1 μm to 5 μm.

Here, although the case where titanium dioxide particle is used as an example of a photocatalyst particle is demonstrated here as an example, a photocatalyst particle does not necessarily need to be a titanium dioxide particle, For example, a tungsten oxide, a tin oxide, etc. It may be. However, considering that it is inexpensive, has excellent chemical stability, and contains high photocatalytic activity, it is preferable to employ titanium dioxide as the photocatalyst.

Further, in the present embodiment, the water-soluble metal salt of iron chloride (FeCl _3), i.e., iron (Fe), for example a lift description, but the sensitizer will be iron (Fe) the case of using the water-soluble metal salt as an example of the sensitizer or It does not need to be a water-soluble metal complex, but may be a water-soluble metal salt such as copper (Cu), chromium (Cr), nickel (Ni), or a water-soluble metal complex. However, considering that it is inexpensive, it is preferable to employ a water-soluble metal salt of iron (Fe) or a water-soluble metal complex as a sensitizer.

Table 1 shows the titanium oxide crystal strength counts by XRD measurement for water slurry concentrations of 10% and 30% by weight. In addition, "titanium oxide crystal strength count" has shown the adhesion rate (presence rate) of a material.

Water slurry concentration
[weight%] Titanium Oxide Crystal Strength
[count] 10 480 30 630

As can be seen in Table 1, when the water slurry concentration is 10% by weight compared with the case of 30% by weight, the higher the water slurry concentration, the material input amount is increased, the adhesion amount can be increased. On the other hand, when the water slurry concentration exceeds 30% by weight, the viscosity of the water slurry is excessively increased, and supplying at the time of spraying becomes difficult. Therefore, in this embodiment, the water slurry concentration is made into 30 weight%.

[2. Thermal Spray Forming Process]

As an example of the manufacturing method of the photocatalyst film to which this invention is applied, it sprays using the produced water slurry then, and forms a photocatalyst film.

Here, in the thermal spray coating process, for example, a high-temperature spraying speed of the thermal spraying variable type described in Japanese Patent Application Laid-Open No. 2005-68457 can be used. Specifically, as shown in FIG. The water slurry generated in the high speed flame (frame) ejected from the spray gun is pumped, and the photocatalyst film is formed by colliding with the target substrate at high speed. In addition, by mixing high pressure air with high pressure oxygen in a booster compressor, the oxygen consumption is reduced and the flame (frame) is further accelerated.

In this case, the thermal spraying conditions are flame (frame) temperature of 700 ~ 2500 ℃, the spraying speed is 800 ~ 2000m / sec.

Moreover, after measuring the temperature in each position of 280 mm, 300 mm, 350 mm, and 450 mm on a flame (frame) centerline from the tip of a spray gun, the average temperature is made into flame (frame) temperature. In addition, the temperature is measured by contacting the flame with a thermocouple (for example, SUS material up to about 1000 ° C, and tungsten / rhenium (WW · Re) thermocouple) without adding water slurry and mixing air. Was carried out. The same holds true for this point.

3 is an analysis result of the crystal structure using the X-ray diffraction apparatus (XRD) of the photocatalyst film obtained by the method for producing a photocatalyst film to which the present invention described above is applied.

Here, in the photocatalyst coating film obtained by the production process of the photocatalyst film according to the present invention, for example FeO (OH) and the first peak ratio of Fe ₂ O _3, "FeO (OH) with: Fe ₂ O ₃ = 2.25: 1 ", and the ratio of FeO (OH) which contributes to visible mineralization of a photocatalyst is high.

Also, FeO (OH) is oxidized in the case of the Fe ₂ O ₃ generated, Fe ₂ O ₃ is The function as a promoter appears but does not contribute to the visible light response, resulting in deterioration of the visible light response. However, in the photocatalyst film obtained by the method of manufacturing the photocatalyst film to which the present invention is applied, as shown in FIG. 3, there is almost no peak of Fe ₂ O ₃ , and it can be seen that degradation of visible light response characteristics due to thermal spraying is minimized.

Here, the electron micrograph and the component analysis and the element distribution analysis of the photocatalyst film obtained by the method of manufacturing the photocatalyst film to which the present invention is applied using a scanning electron microscope-energy dispersive X-ray analyzer (SEM-EDS) As a result, in the photocatalytic film obtained by the method for producing a photocatalytic film to which the present invention is applied, it became clear that Cl contamination and the like do not exist as described later. This is considered to be because Cl added to the water slurry in the ionic state volatilized by the thermal spraying and diffused into the atmosphere before reaching the object (substrate), thereby achieving a high-purity photocatalyst coating. In addition, the EDS analysis result of the photocatalyst film obtained by the manufacturing method of the photocatalyst film which applied this invention is shown in b of Table 2.

Sample Element (wt%) Ti Fe O Si Al Cl a 52.30 0.58 45.37 0.84 0.41 0.51 b 64.76 0.69 33.51 0.48 0.56 N.D. c 61.06 1.54 35.86 0.97 0.58 N.D.

4 is a result of analyzing a crystal structure using XRD of a photocatalyst film obtained by a conventional method for producing a photocatalyst film.

Specifically, the TiO ₂ powder was mixed with FeCl ₃ such that the Ti component of the rutile titanium dioxide powder (TiO ₂ ) and the Fe component of the iron chloride solution (FeCl ₃ ) were Ti: Fe = 99: 1 in weight ratio. The solution is stirred for 2 hours, and Fe is supported on the TiO ₂ powder. Next, the solution was dried, pulverized, classified into particle sizes, and the particle size was adjusted to about 100 µm. Subsequently, the photocatalyst film is formed by thermal spraying using a powder slurry of water (concentration 30% by weight), and the obtained photocatalyst film is analyzed by XRD for the crystal structure. In addition, the manufacturing method of such a photocatalyst film is called "dedicated support method" for convenience.

However, a dedicated supporting method, that is, titanium dioxide (TiO ₂ ) is immersed in an aqueous solution of iron chloride (FeCl ₃ ) serving as a sensitizer in advance and stirred to carry iron or an iron compound on titanium dioxide, and titanium dioxide on which iron or an iron compound is supported. In the method of making the photocatalyst composition, it takes a long time to process, and a drying process may take place, and it is thought that aggregation, growth, segregation, etc. of iron and iron compounds supported on the surface of titanium dioxide are likely to occur in the meantime.

On the other hand, in the present invention, since the water slurry in which the sensitizer or the antibacterial metal compound is dissolved at the molecular level is instantaneously fixed to the surface of the titanium dioxide by thermal spraying, the sensitizer or the antimicrobial metal compound is dispersed in the nano size and supported on the titanium dioxide surface. I think.

Therefore, since the sensitizer and antibacterial metal compound of this invention are very excellent in dispersibility compared with the prior art, it is thought that the high sensitization effect and antibacterial effect exceeded expectation can be acquired.

Here, in the results shown in FIG. 4, both peaks of FeO (OH) and Fe ₂ O ₃ can be observed, and FeO (OH), which contributes to the visible light of the photocatalyst, is oxidized by the heat during the thermal spraying and is visible. does not contribute can be seen that the Fe ₂ O ₃ in.

Also, FeO (OH) with, for the first peak ratio of Fe ₂ O _{3, "FeO (OH): Fe 2 O} 3 = 1.78: 1 " and the photocatalyst coating film obtained by the production process of the photocatalyst film according to the present invention It can be seen that the ratio of Fe ₂ O ₃ is high as compared with. In addition, since the ratio of Fe ₂ O ₃ is high, visible light responsiveness is not sufficient.

Here, the Cl component could be confirmed from the electron micrograph using the SEM-EDS of the photocatalytic film obtained by the exclusive supporting method, and the component analysis of the element and the distribution analysis of the element. This is considered to be due to the influence of FeCl ₃ used during Fe loading. That is, it is considered that Cl forms a compound at the time of carrying, and it becomes the state which does not volatilize by thermal spraying, and there exists a possibility that the photocatalyst characteristic of a photocatalyst film may fall due to contamination of such an impurity. In addition, the EDS analysis result of the photocatalyst film obtained by the exclusive supporting method is shown in a of Table 2.

5 is an analysis result of the crystal structure using XRD of the photocatalyst film obtained by supporting iron after the film formation of the titanium dioxide film.

Specifically, a TiO ₂ film was formed by thermal spraying using a water slurry (concentration 30% by weight) of rutile type titanium dioxide powder (TiO ₂ ), and the formed film was coated with FeCl so that Ti: Fe = 99: 1 in weight ratio. ₃₂ hours immersed in a solution is a result of the analysis of the crystal structure by XRD photocatalytic coating bearing the Fe, and TiO ₂ film obtained in this way to the Fig. In addition, the manufacturing method of such a photocatalyst film is called the "support method" for convenience.

In the results shown in Fig 5, the peak of Fe ₂ O ₃ it was not observed. This is because FeO (OH) is not affected by thermal effects of thermal spraying.

Here, in the results of electron micrographs using the SEM-EDS of the photocatalytic coating obtained by the post-supporting method, and the component analysis of the element and the distribution analysis of the element, the ratio of Ti and Fe was compared with the photocatalyst coating obtained by the present invention and the exclusive supporting method. It is high. This is considered to be because Fe segregated on the analytical surface due to the characteristics of the backing method in which Fe is supported on the coating surface. In such a case, since Fe does not exist in the film when the film is worn, there is a concern that the life of visible light response characteristics is short. In addition, the EDS analysis result of the photocatalyst film obtained by the back support method is shown in Table 2c.

As is clear from the above, in the case of the dedicated supporting method, (1) a long time is required to support iron, (2) the visible light responsiveness is not good because the ratio of FeO (OH) is low, and (3) There is a concern that the solution adversely affects. In addition, in the case of the supporting method, Fe is segregated on the surface and there is a concern that the life of visible light responsiveness is short.

On the other hand, in the photocatalyst film obtained by the manufacturing method of the photocatalyst film to which the present invention is applied, such a problem does not occur, and the visible light responsiveness and the long life of the visible light responsiveness are realized.

Moreover, in the manufacturing method of the photocatalyst film which applied this invention, the titanium dioxide powder of rutile type crystal structure is cheap compared with an anatase type crystal structure, and cost reduction is realized.

Here, the gas decomposition performance test of the photocatalyst film was done.

The conceptual diagram of the evaluation test method is shown in FIG. The test piece of the thermal spray coating used for evaluation was about 50 mm square, and the ceramic tile was used for the base material. The test piece was pre-treated with alcohol in advance and irradiated with ultraviolet rays (ultraviolet intensity: 1 mW / cm ² ) for 12 hours, and used for the evaluation test of gas decomposition.

Gas to be decomposed was adjusted using acetaldehyde and adjusted to about 450 ppm in a tether bag (gas bag; 125 cc). The light source used LED light (wavelength 415 nm), and irradiated the wavelength surface of the sample with the light intensity of 6 mW / cm <^2> .

The sample which tested was the photocatalyst film obtained by the manufacturing method of the photocatalyst film which applied this invention, and the photocatalyst film obtained by the backing method. For comparison, a test was also conducted with a commercially available photocatalyst tile and a sulfur dope titanium oxide thermal spray coating which is a visible light fluorescent catalyst.

The acetaldehyde gas decomposition test results of each film are shown in FIGS. 7 and 8.

It can be seen from FIG. 7 and FIG. 8 that the photocatalytic coating obtained by the method for producing a photocatalytic coating according to the present invention exhibits high acetaldehyde gas decomposition activity. In addition, about twice the amount of acetaldehyde can be seen with respect to carbon dioxide, and it is thought that complete decomposition was achieved.

On the other hand, the photocatalyst film obtained by the backing method showed the same gas removal performance as compared with sulfur dope titanium oxide. However, the amount of carbon dioxide generated was less than that of the photocatalytic coating obtained by the method for producing a photocatalytic coating to which the present invention was applied, and the acid taste which was considered to be an intermediate product after the test was obtained. Therefore, it is assumed that the gas decomposition reaction in this case was not complete.

Gas decomposition test results conducted on commercially available photocatalyst tiles resulted in considerably lower decomposition activity compared with the photocatalyst film obtained by the method for producing a photocatalyst film to which the present invention was applied.

In addition, the bactericidal effect of the photocatalytic coating was also evaluated.

The conceptual diagram of the evaluation test method is shown in FIG. The test piece of the thermal spray coating used for evaluation was about 50 mm square, and the ceramic tile was used for the base material. The test piece was acetone-washed on the surface, subjected to pretreatment irradiated with ultraviolet rays (ultraviolet intensity: 1 mW / cm ² ) for 6 hours to provide an antibacterial evaluation test.

Evaluation test method was to install each sample in a chalet (90 mm diameter), add 30 ml of E. coli suspension, and leave it at 30 ° C under irradiation conditions (roughness of 1700 lux) by fluorescent lamps. Measurement was made over time. In addition, the measurement of the bacteria count was made into the colony count method.

The sample evaluated was a photocatalyst film obtained by the manufacturing method of the photocatalyst film to which this invention was applied, a sulfur dope titanium oxide film, and a commercial photocatalyst tile. The evaluation test results are shown in FIG.

In FIG. 10, the bactericidal power of the photocatalyst coating obtained by the method of manufacturing the photocatalyst coating to the present invention exhibits a high bactericidal property of 4 orders at 30 minutes and 4 orders at 180 minutes. This did not reach the sterilizing power of 6 orders in 30 minutes seen with sulfur-doped titanium oxide, but it can be said to have sufficient performance for practical use. In addition, commercially available photocatalyst tiles were of low performance, showing little reduction in the number of viable cells even when compared to the blanks.

<2. Variation 1

In the method for producing a photocatalytic coating according to the present invention, a water slurry using a rutile titanium dioxide powder and an iron chloride aqueous solution is produced, but a water slurry using an anatase type titanium dioxide powder and an iron chloride aqueous solution may be produced. Specifically, for example, a water slurry using an anatase-type titanium dioxide powder having a particle diameter of about 10 nm and an aqueous iron chloride solution may be produced. In this case, in the water slurry, the anatase-type titanium dioxide powder aggregates to form a particle diameter of about 1 μm to 5 μm.

However, in the anatase type titanium dioxide powder, it is difficult for the excitation electrons excited in visible light to exceed the bandgap, and the visible light responsiveness is hard to come out. And then coated on the object. Specifically, the photocatalyst film needs to be formed by setting the flame (frame) temperature at a high temperature of 2000 ° C. or higher and changing the crystal structure of the titanium dioxide powder to rutile type by thermal during thermal spraying. Therefore, when supporting FeO (OH), it is preferable not to use expensive anatase type titanium oxide, but to use rutile type titanium oxide from the beginning.

<3. Variation 2

In the method for producing a photocatalytic coating to which the present invention is applied, a case where a visible light responsive catalyst film is realized by carrying FeO (OH) showing a visible light response function on a rutile titanium dioxide powder is described as an example.

However, the supporting on the photocatalyst particles need not be limited to the visible light response function, and may be Fe ₂ O ₃ or the like which exhibits the cocatalyst function.

Specifically, for example, anatase-type titanium dioxide powder having a particle size of about 10 nm and a water slurry using an iron oxide aqueous solution are produced (in this case, anatase-type titanium dioxide powder is agglomerated and 1 µm to 5 µm). Anatase-type titanium dioxide bearing Fe ₂ O _3, which exhibits a cocatalyst function, may be laminated using a generated water slurry to form a photocatalyst film.

In this case, the thermal spraying conditions are chlorine (frame) temperature of 300 ~ 2000 ℃, spraying speed is 800 ~ 2000m / sec.

In addition, anatase type titanium dioxide may exhibit higher catalytic activity than rutile type titanium dioxide.

<4. About the support

In one example of the method for producing a photocatalyst coating to which the present invention is applied, a titanium dioxide film carrying at least one type of iron oxide, hydroxide, and oxyhydroxide is sprayed by spraying with a water slurry using titanium dioxide powder and an aqueous iron chloride solution. Although the case where the film is formed into a film is described as an example, a titanium dioxide film supporting at least one type of not only iron but also silver oxide, hydroxide and oxyhydroxide may be formed.

Specifically, for example, titanium oxide powder (TiO ₂₎ Ti component and the iron chloride solution (FeCl ₃₎ Ti as a weight ratio of Fe component in the: Fe = 99.7:, so that the 0.3 In addition, the titanium oxide powder (TiO ₂₎ To produce a water slurry (concentration 30% by weight) using a rutile titanium dioxide powder, an aqueous solution of iron chloride and an aqueous solution of silver nitrate such that the Ti component of the solution and the Ag component of the silver nitrate solution (AgNO ₃ ) are in a weight ratio of Ti: Ag = 99: 1. Then, the resulting water slurry may be sprayed to form a photocatalyst film.

As a result of this film formation, it is possible to add very high antibacterial function to the photocatalyst film by supporting silver oxide (AgO ₂ ), a kind of antibacterial metal, on the rutile titanium dioxide film having visible light response function and cocatalyst function. It is effective in preventing infection and food poisoning when applied to flooring, wall, ceiling or other facilities in sanitary facilities such as food processing plants.

Here, it can be seen from the surface observation results (not shown) of the photocatalyst film obtained by the above-described method for producing a photocatalyst film that the nano-sized silver oxide is dispersed uniformly without segregation. In addition, it is possible to exhibit a stable antimicrobial effect by dispersing the silver oxide in a substantially uniform manner.

However, the surface observation using SEM-EDS of the photocatalyst film obtained by the exclusive supporting method was performed.

Specifically, the TiO ₂ powder was stirred in the FeCl ₃ solution for 2 hours so that the Ti component of the titanium dioxide powder (TiO ₂ ) and the Fe component of the aqueous iron chloride solution (FeCl ₃ ) were Ti: Fe = 99.7: 0.3 in weight ratio, and then the TiO ₂ Fe was supported on the powder. Then, Ag component of the Ti component and a silver nitrate aqueous solution (AgNO ₃₎ of the titanium oxide powder (TiO ₂₎ is a Ti weight ratio: Ag: 99: silver nitrate aqueous solution was added in the solution to be 1, and the mixture was stirred and irradiated with ultraviolet rays TiO ₂ The powder was also loaded with Ag. Next, the solution was dried to classify the particle size after grinding to match the particle size. Subsequently, the photocatalyst film was formed by thermal spraying using a powder slurry of water (concentration 30% by weight), and surface observation using SEM-EDS of the photocatalyst film thus obtained was performed.

As a result, it turned out that silver segregation of 3 micrometers or more exists. In addition, when silver segregates, the photocatalytic function and the antibacterial effect vary depending on the place, and the performance of the photocatalytic coating becomes unstable.

Moreover, the surface observation using SEM-EDS of the photocatalyst film obtained by the back support method was performed.

Specifically, by spraying using a water slurry (concentration 30% by weight) of titanium dioxide powder (TiO ₂ ) to form TiO ₂ The film was formed, and the film formed was immersed in FeCl ₃ solution for 2 hours in a weight ratio of Ti: Fe = 99.7: 0.3 to support Fe in the TiO ₂ film. Subsequently, silver nitrate was immersed in an aqueous solution of silver so as to have a Ti: Ag = 99: 1 ratio by weight, irradiated with ultraviolet light to support Ag on the TiO ₂ film, and surface observation using SEM-EDS of the photocatalytic film thus obtained was performed. 11 and 12 show the results of the gas decomposition test and the sterilization test using this film.

As a result, it turned out that silver segregation of 3 micrometers or more exists. In addition, when silver segregates, the photocatalytic function and the antibacterial effect vary depending on the place, and the performance of the photocatalytic coating becomes unstable.

In addition, the presence of thick silver segregation in the coating surface layer was confirmed, and there is a concern that the photocatalyst performance deteriorates due to the decrease in light intensity reaching titanium dioxide due to the silver segregation in the surface layer.

In addition, it can be seen from FIG. 11 that 300 ppm of acetaldehyde is decomposed at 120 min. In addition, carbon dioxide is also generated in the volume can be confirmed that the complete decomposition. In addition, in FIG. 12, 10 ⁶ cfu / mL of E. coli was set to 0 at 180 min, indicating high sterilization performance.

<5. About Support of Pigments>

In one example of the method for producing a photocatalyst coating to which the present invention is applied, a case of forming a titanium dioxide coating on which iron is formed by spraying using a water slurry using titanium dioxide powder and an aqueous solution of iron chloride is described as an example. Alternatively, a film of titanium dioxide carrying a pigment may be formed. In addition, by supporting the pigment, the photocatalyst coating can be colored, and a change in color occurs depending on the degree of deposition of the pigment.

Here, the water slurry (concentration 30% by weight so that the Ti component of the titanium dioxide powder (TiO ₂ ) and the pigment (components are mica (mica), TiO ₂ , Fe ₂ O ₃ ) in a weight ratio of Ti: pigment = 7: 3. Fig. 13 shows the results of analysis of the crystal structure by XRD of the photocatalyst film which was formed by thermal spraying using the produced water slurry.

In the result shown in FIG. 13, it can be confirmed that the peak of Fe ₂ O ₃ is small and the adhesion ratio of the pigment is low.

Here, in the results of electron micrographs using the SEM-EDS of the photocatalytic film obtained by the above method and the results of the component analysis and distribution analysis of the elements (not shown), the yield of the pigments as compared with the case of the dedicated paper described later It was found that this was low.

Fig. 14 shows the results of analysis of the crystal structure using XRD of the photocatalytic film obtained by the exclusive supporting method.

Specifically, the two powders are mixed so that the Ti component of the titanium dioxide powder (TiO ₂ ) and the pigment are in a weight ratio of Ti: pigment = 7: 3, and the pellet obtained by firing at 1200 ° C. for 30 minutes is pulverized, and the particle size is classified. Was carried out to match the particle size to about 100 mu m. Subsequently, the photocatalyst was formed by thermal spraying using the powder slurry of water (concentration 30% by weight), and the crystal structure of the photocatalyst film thus obtained was analyzed by XRD.

The results shown in Figure 14, the peak of Fe ₂ O ₃ component of the pigment large, it can be seen that the pigment is attached to lot.

Here, in the result of electron micrograph using SEM-EDS of the photocatalytic film obtained by the above-mentioned dedicated electrolytic method and the component analysis of the element and the distribution of the element (not shown), Fe as the pigment component is about 16% of Ti. The yield was found to be high. This is considered to be because the mass of particles increased by compounding the pigment and the TiO _2.

Fig. 15 shows the results of analysis of the crystal structure using XRD of the photocatalytic film obtained by the backing method.

Specifically, a TiO ₂ film is formed by thermal spraying using a water slurry (concentration 30% by weight) of titanium dioxide powder (TiO ₂ ). Next, after the pigment was applied to the TiO ₂ film with water slurry (concentration 30% by weight), the composite structure of TiO ₂ and the pigment obtained by firing at 1250 ° C. for 1 hour was analyzed by XRD. to be.

The results shown in Figure 15, do not have a peak of TiO ₂ is, it is believed the surface over the X-ray penetration depth ditches pigment is covered.

Here, the ratio of Ti is very low and the surface is pigmented by electron micrographs using the SEM-EDS of the photocatalytic coating obtained by the above-described supporting method, and the component analysis and distribution of the element (not shown). It can be seen that is completely covered. Due to such pigments, there is a concern that the photocatalytic function of light intensity reaching the titanium dioxide is lowered.

Claims (9)

Forming a slurry comprising a photocatalyst coating, at least one compound selected from a water-soluble metal complex or water-soluble metal salt of Fe, Cu, Cr, Ni, and water, and
At least one type of Fe, Cu, Cr, Ni hydroxide, oxyhydroxide, or oxide produced by thermally spraying the slurry with metal ions of the at least one kind of the compound is supported on the photocatalytic particles in the slurry ( Iii) and simultaneously laminating the photocatalyst particles on the object.
Method for producing a photocatalytic coating. The method of claim 1,
Hydroxides, oxyhydroxides or oxides of Fe, Cu, Cr, and Ni exhibit visible light response
Method for producing a photocatalytic coating. 3. The method according to claim 1 or 2,
The photocatalyst particles are rutile titanium dioxide particles
Method for producing a photocatalytic coating. The method according to claim 1, 2 or 3,
Forming the slurry including at least one selected from an antibacterial metal, an antibacterial metal salt or an antibacterial metal complex,
The slurry is sprayed to stack the antimicrobial metal, antimicrobial metal salt or antimicrobial metal complex together with the photocatalyst particles on an object in at least one type selected from metal, metal salt, metal complex, oxyhydroxide, hydroxide or oxide.
Method for producing a photocatalytic coating. The method according to claim 1, 2 or 3,
A pigment is formed to form the slurry,
Spraying the slurry to laminate a pigment together with the photocatalyst particles onto an object
Method for producing a photocatalytic coating. The method according to claim 1, 2 or 3,
An adsorbent is formed to form the slurry,
The slurry is sprayed, and the photocatalyst particles and the adsorbent are laminated on the object
Method for producing a photocatalytic coating. Forming a slurry comprising photocatalyst particles, at least one compound selected from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, and Ni, and water, and
Spraying the slurry to laminate the photocatalyst particles contained in the slurry onto an object;
Method for producing a photocatalytic coating. Forming a slurry comprising photocatalyst particles, at least one compound selected from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, and Ni, and water,
By spraying the slurry, at least one type of Fe, Cu, Cr, Ni hydroxide, oxyhydroxide or oxide produced by the reaction of the metal ions of the at least one compound with water is supported on the photocatalytic particles in the slurry. And the photocatalyst particles prepared by laminating the object
Photocatalytic coating. Forming a slurry comprising photocatalyst particles, at least one compound selected from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, and Ni, and water,
By spraying the slurry, the photocatalyst particles contained in the slurry is laminated on an object
Photocatalytic coating.

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