KR101478234B1 - Method for producing photocatalyst coating film, and photocatalyst coating film - Google Patents

Abstract

The object of the present invention is to realize a high production yield of a titanium dioxide film carrying iron. To accomplish this purpose, a water slurry is prepared by mixing titanium dioxide powder and aqueous solution of iron chloride, and the resulting water slurry is sprayed by spraying technique. Since the photocatalyst coating film can be formed while FeO (OH) is supported on the titanium dioxide powder at the time of spraying, the production yield can be remarkably improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a photocatalyst coating film, and a photocatalyst coating film,

The present invention relates to a method for producing a photocatalyst coating film and a photocatalyst coating film. More specifically, the present invention relates to a photocatalytic coating film and a photocatalytic film, which include, for example, a photocatalytic function capable of harmlessly decomposing pollutants, antibacterial and sterilizing.

With the progress of aging society, the percentage of the elderly people whose immunity is decreased is increasing in the whole population, and as a result, from the viewpoint of prevention of infectious diseases and food poisoning, strengthening hygiene management at medical field, food production and processing site Is becoming an urgent task. Based on this social background, various antibacterial processing products have been developed, and recently, the use of the photocatalytic function in antibacterial processing has received particular attention.

Here, " photocatalytic function " means that when light energy larger than the band gap energy of the conduction band and the valance band is irradiated, the photocatalyst function becomes an excited state, and a catalytic substance that generates an electron- Optical semiconductor material).

Among the photocatalysts, titanium dioxide (TiO ₂ ), that is, a photocatalyst using titanium dioxide particles having a rutile crystal structure is inexpensive, has excellent chemical stability, and has a high catalytic activity. It is possible to simultaneously decompose harmful substances such as endotoxin, which is an outer wall of the cell walls of gram-negative bacteria, and toxins produced by bacteria (for example, berotoxin produced by pathogenic Escherichia coli), at the same time as the cells and the advantage that the photocatalyst itself is harmless to the human body Lt; / RTI >

For this reason, research and application of photocatalysts using titanium dioxide are under way, and titanium dioxide photocatalysts are widely used for antibacterial processing of food containers, building materials, etc. (see, for example, Patent Documents 1 and 2 ).

In addition, since titanium dioxide does not exhibit photocatalytic activity only under ultraviolet irradiation, it can not exhibit sufficient catalytic activity under the room light containing almost no ultraviolet component. Therefore, there is known a technique of expressing photocatalytic activity under visible light irradiation by supporting a metal such as iron or a metal complex such as FeCl ₃ or a metal salt, that is, an iron compound, on titanium dioxide.

However, in the case of producing a photocatalytic coating that exhibits photocatalytic activity under visible light irradiation, a photocatalytic composition containing a titanium dioxide powder on which a sensitizer is impregnated is dispersed, for example, in a paint or the like, To prepare a photocatalyst coating film.

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

Patent Document 1: JP-A-2007-51263 Patent Document 2: JP-A 2006-346651 Patent Document 3: JP-A-2007-090336

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

It is an object of the present invention to provide a method for manufacturing a photocatalytic coating and a photocatalytic coating which can be shortened in manufacturing process, stabilized in quality, and reduced in cost.

In order to achieve the above object, a method for producing a photocatalytic coating according to the present invention is a method for producing a photocatalytic film, comprising: preparing a photocatalyst particle, at least one kind of compound selected from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, And at least one type of hydroxide, oxide hydroxide or oxide of Fe, Cu, Cr, or Ni produced by the reaction of the metal ion of the at least one kind of compound with water by spraying the slurry into the slurry And a step of laminating the photocatalyst particles on the object.

At least one kind of compound selected from water-soluble metal complexes of water-soluble metal complexes of Fe, Cu, Cr and Ni, and water and a slurry are formed, and the slurry is sprayed to form Fe, Cu, Cr, The metal ion of the water-soluble metal complex of Ni or the water-soluble metal salt reacts with water to produce hydroxides, oxy-oxides or oxides of nano-sized very fine Fe, Cu, Cr, Ni, and these hydroxides, oxides, As shown in FIG.

Further, the slurry is sprayed to carry at least one type of hydroxide, oxide hydroxide or oxide of Fe, Cu, Cr, or Ni produced by the reaction of the metal ion of the at least one kind of the compound with water onto the photocatalyst particles in the slurry At the same time, the photocatalyst particles are laminated on the object, that is, before the photocatalyst particles are laminated on the object, at least one kind of hydroxide, oxide, oxides or oxides of Fe, Cu, By spraying the slurry, nano-sized extremely fine hydroxides, oxides or oxides of Fe, Cu, Cr and Ni are dispersed and supported on the surface of the photocatalyst particles, thereby achieving a remarkable shortening of the manufacturing process and stabilization of the performance and quality of the photocatalytic functional film can do.

Further, roneun "Fe, Cu, Cr, water-soluble metal complexes of Ni", for _{example, [Cu (NH 3) 4} ] 2+, [Fe (CN) 6] 4-, [Fe (CN) 6)] 3 ^{_{-, C 10 H 12 FeN 2}} O may be _{mentioned. 8} or the like, the "Fe, Cu, Cr, water-soluble metal salt of Ni", for _{example, FeCl 3, Fe 2 (SO} 4) 3, Fe (NO 3) ₃ , CuSO ₄ , Cu (NO ₃ ) ₂ , CuCl ₂ , Ni (NO ₃ ) ₂ , NiCl ₂ , NiSO ₄ and Cr (NO ₃ ) ₃ .

Examples of the hydroxides, oxides and oxides of Fe, Cu, Cr and Ni produced by the reaction of water-soluble metal complexes of Fe, Cu, Cr and Ni with water include CuO, Cu (OH) ₂ , FeO (OH), and the like Fe (OH) _3, roneun "Fe, Cu, Cr, Fe metal salt of Ni that is generated reacts with water, Cu, Cr, oxides of Ni, oxy-oxide or oxide", 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 sprayed frame comes close to a vacuum state at high speed in the spraying process, the reaction of metal ions of water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr, and Ni with oxygen in water and air in the slurry occurs, Oxides or oxides, and anions such as chlorine ions and nitrate ions are thought to be volatilized by thermal spray and diffuse into the atmosphere.

Here, when a hydroxide, an oxyhydroxide or an oxide of Fe, Cu, Cr, or Ni exhibits a visible light responsive function, the hydroxide, oxide hydroxide or oxide of Fe, Cu, Cr or Ni supported under visible light irradiation is excited, The electron moves to the side of the photocatalyst particles, so that oxidation reaction occurs on the surface of hydroxides, oxides, or oxides of Fe, Cu, Cr, and Ni, and reduction reaction occurs on the surface of the photocatalyst particles to thereby manifest visible light responsiveness (see FIG. .

(OH), Fe (OH) ₃ , Cu (OH) ₂ , CuO, Ni (OH) ₂ , and NiO (OH) ₂ as the hydroxide, oxyhydroxide or oxide of Fe, Cu, OH), Cr (OH) ₃ , Cr ₂ O (OH) ₄ , Cr ₂ O ₃ and the like.

When the hydroxides, oxides or oxides of Fe, Cu, Cr or Ni exhibit a promoter function, the photocatalyst particles are excited under irradiation with ultraviolet rays, and the excited electrons are hydroxides of Fe, Cu, Cr and Ni, Oxidation proceeds on the surface of the photocatalyst particle, and oxidation reaction, reduction reaction occurs on the surface of hydroxides, oxyhydroxides or oxides of Fe, Cu, Cr and Ni, and the photocatalyst performance is improved by charge separation (see FIG.

Examples of hydroxides, oxy-oxides or oxides of Fe, Cu, Cr and Ni exhibiting a promoter function include Fe ₂ O ₃ , CuO and NiO.

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

At least one kind of compound selected from water-soluble metal complexes of water-soluble metal complexes of Fe, Cu, Cr and Ni, and water and a slurry are formed, and the slurry is sprayed to form Fe, Cu, Cr, The metal ion of the water-soluble metal complex of Ni or the water-soluble metal salt reacts with water to produce hydroxides, oxy-oxides or oxides of nano-sized very fine Fe, Cu, Cr and Ni, and these hydroxides, As shown in FIG.

Further, it is preferable that the slurry is sprayed and the photocatalyst particles contained in the slurry are laminated on the object, that is, before the photocatalyst particles are laminated on the object, at least one kind of hydroxide, oxide hydroxide or oxide of Fe, Cu, Oxides or oxides of nano-sized extremely fine Fe, Cu, Cr and Ni are dispersed and supported on the surfaces of the photocatalyst particles by spraying the slurry without supporting the photocatalyst particles on the photocatalyst particles, It is possible to achieve the stabilization of the performance and the quality.

The slurry containing the photocatalyst particles such as titanium dioxide may contain an antibacterial metal (for example, at least one of silver, copper, zinc, aluminum, nickel, cobalt or chromium) A metal salt or an antimicrobial metal complex and an antimicrobial metal or an antimicrobial metal complex with a photocatalyst particle is selected from a metal, a metal salt, a metal complex, an oxyhydroxide, a hydroxide or an oxide by spraying a slurry containing an antimicrobial metal, an antimicrobial metal salt or an antimicrobial metal complex , And a photocatalytic functional coating film containing a strong antibacterial action can be produced.

Further, photocatalyst particles containing pigments can be laminated by adding a pigment to a slurry containing photocatalyst particles such as titanium dioxide and spraying a slurry containing the photocatalyst particles and a pigment together, and a photocatalyst film can do.

Further, the adsorbent can be laminated together with the photocatalyst particles by adding an adsorbent (e.g., zeolite or the like) to the slurry containing the photocatalyst particles such as titanium dioxide and spraying the slurry containing the photocatalyst particles and the adsorbent together, A photocatalyst coating film having a gas adsorption function can be produced.

In order to achieve the above object, the photocatalytic coating film of the present invention is formed by forming a slurry containing at least one kind of compound selected from water-soluble metal complexes or water-soluble metal salts of photocatalytic particles, Fe, Cu, Cr and Ni, And at least one type of hydroxide, oxide, hydroxide or oxide of Fe, Cu, Cr, or Ni produced by the reaction of the metal ion of the at least one kind of compound with water by spraying the slurry is added to the photocatalyst particles in the slurry And the photocatalyst particles were laminated on the object.

Further, the photocatalytic coating of the present invention is characterized in that a photocatalytic particle and at least one kind of compound selected from water-soluble metal complexes or water-soluble metal salts of Fe, Cu, Cr and Ni and a slurry containing water are formed, And laminating the photocatalyst particles contained in the slurry on the object.

Examples of objects to be laminated with the photocatalyst particles include tiles, sanitary ware, glass, mirrors, concrete construction materials, resin construction materials, metal building materials, resin films, metal fibers, glass fibers, carbon fibers, .

In the method for producing a photocatalyst film to which the present invention is applied, since the photocatalyst film can be produced by a greatly shortened manufacturing process, irregularity in the quality and performance of the film is reduced, and high quality and manufacturing yield can be realized. In addition, high quality can be realized for the photocatalyst coating film to which the present invention is applied.

1 (A) is a schematic diagram for explaining a visible light response function.
1 (B) is a schematic diagram for explaining the promoter function.
2 is a schematic view for explaining a spraying apparatus.
Fig. 3 shows the results of the analysis of the crystal structure of the photocatalyst film obtained by the method for producing a photocatalyst film to which the present invention is applied, using XRD.
FIG. 4 shows the result of analysis of the crystal structure of the photocatalyst film obtained by the conventional method for producing a photocatalyst film using XRD.
Fig. 5 shows the results of analysis of the crystal structure of the photocatalyst film obtained by carrying iron after the film formation of the titanium dioxide film using XRD.
6 is a conceptual diagram of a test evaluation method of the gas decomposition performance test of the photocatalytic coating.
Fig. 7 shows the results of acetaldehyde gas decomposition test (1).
Fig. 8 shows the results of the acetaldehyde gas decomposition test (2).
9 is a conceptual diagram of a test method for evaluating the sterilizing effect of the photocatalytic coating.
Fig. 10 shows the results of an evaluation test of the sterilizing effect of the photocatalytic coating.
11 shows the results of the decomposition test on acetaldehyde gas of the photocatalyst film to which the present invention is applied.
Fig. 12 shows the result of sterilization test for E. coli of the photocatalytic coating film to which the present invention is applied.
Fig. 13 shows the results of the analysis of the crystal structure of the photocatalyst film carrying the pigment by XRD.
14 shows the results of the analysis of the crystal structure of the photocatalyst film obtained by the X-ray diffraction (XRD) method.
Fig. 15 shows the results of the analysis of the crystal structure of the photocatalyst film obtained by the post mortem method (XRD).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the invention (hereinafter referred to as " embodiments ") will be described with reference to the drawings.

<1. About iron bearing>

An example of a method for producing a photocatalyst film to which the present invention is applied is composed of two processes: (1) a water slurry production process; and (2) a thermal spray film formation process. Hereinafter, each process will be described in detail.

[One. Water slurry production process]

An example of a method for producing a photocatalytic film to which the present invention is applied is a method in which a titanium dioxide powder such that a Ti component of a titanium dioxide powder (TiO ₂ ) and an Fe component of an aqueous solution of iron chloride (FeCl ₃ ) are contained in a weight ratio of Ti: Fe = To produce an aqueous slurry (concentration 30% by weight) using an aqueous solution of iron chloride.

Specifically, a water slurry is formed using a rutile type titanium dioxide powder having a particle diameter of about 30 nm and an aqueous solution of iron chloride. In addition, in the water slurry, the rutile type titanium dioxide powder agglomerates to form a particle size of about 1 to 5 mu m.

Here, in the present embodiment, the case where titanium dioxide particles are used as an example of the photocatalyst particles is described as an example, but the photocatalyst particles do not necessarily have to be titanium dioxide particles. For example, tungsten oxide, tin oxide . However, it is preferable to employ titanium dioxide as a photocatalyst in consideration of its low cost, excellent chemical stability, and high photocatalytic activity.

In this embodiment, iron chloride (FeCl ₃ ), that is, a water-soluble metal salt of iron (Fe) is used as an example of the sensitizer, but the sensitizer must be a water- It is not necessarily a water-soluble metal complex and may be a water-soluble metal salt or a water-soluble metal complex such as copper (Cu), chromium (Cr), nickel (Ni) However, considering that it is inexpensive, it is preferable to employ a water-soluble metal salt of Fe (Fe) or a water-soluble metal complex as a sensitizer.

Table 1 shows the titanium dioxide crystal strength counts by XRD measurement for cases where the water slurry concentration is 10 wt% and 30 wt%, respectively. Further, &quot; titanium oxide crystal strength count &quot; indicates the deposition rate (existence ratio) of the material.

Water slurry concentration
[weight%] Titanium oxide crystal strength
[count] 10 480 30 630

As can be seen from Table 1, when the water slurry concentration is 10% by weight and 30% by weight, the higher the water slurry concentration, the more the amount of material input and the deposition amount can be increased. On the other hand, if the concentration of the water slurry exceeds 30% by weight, the viscosity of the water slurry becomes excessively high, and feeding (feeding) becomes difficult at the time of spraying. Therefore, in the present embodiment, the water slurry concentration is set to 30 wt%.

[2. Process for forming a thermal spray coating]

As an example of a method for producing a photocatalyst film to which the present invention is applied, a photocatalyst film is formed by spraying using the resulting water slurry.

Here, the high-speed thermal spraying apparatus of the variable spraying temperature type described in JP-A-2005-68457 can be used for the thermal spray film forming process. More specifically, as shown in Fig. 2, The water slurry generated in the high-speed flame (frame) ejected from the spray gun is pumped by the pump and is collided with the target substrate at a high speed to form the photocatalyst film. Further, by mixing high pressure air with high pressure oxygen with a booster compressor, it is possible to further reduce the amount of oxygen used and speed up the flame (frame).

The spray temperature condition in this case is a flame (frame) temperature of 700 to 2500 ° C and a spraying speed of 800 to 2000 m / sec.

Further, the temperature is measured at the positions of 280 mm, 300 mm, 350 mm and 450 mm on the flame (frame) center line from the tip of the spray gun, and the temperature of the average value is set as the flame (frame) temperature. In addition, the temperature is measured by contacting with a flame using a thermocouple (for example, a SUS material up to about 1000 ° C, and a thermocouple of tungsten / rhenium (WW · Re) . The same is true for this point.

Fig. 3 shows the results of the analysis of the crystal structure of the photocatalyst film obtained by the above-described method for producing a photocatalyst film using the X-ray diffraction apparatus (XRD) according to the present invention.

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 &quot;, and the proportion of FeO (OH) contributing to visible light of the 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 cocatalyst appears, but does not contribute to the visible light response characteristic, and as a result, the visible light response characteristic deteriorates. However, as shown in Fig. 3, the photocatalytic coating obtained by the method of producing the photocatalyst film according to the present invention shows almost no peak of Fe ₂ O ₃ and minimizes deterioration of visible light response characteristics due to spraying.

Here, the photomicrographs of the photocatalyst film obtained by the method of manufacturing the photocatalyst film according to the present invention using a scanning electron microscope-energy dispersive X-ray analysis apparatus (SEM-EDS) As a result, in the photocatalytic film obtained by the method for producing a photocatalytic film to which the present invention was applied, it became clear that there was no contamination of Cl as described later. This is presumably because Cl added to the water slurry in the ionic state volatilized by the thermal spray and diffused into the atmosphere before reaching the object (substrate), and a photocatalyst film with high purity can be realized. The results of EDS analysis of the photocatalyst film obtained by the method for producing a photocatalyst film according to the present invention are shown in Table 2 (b).

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.

FIG. 4 shows the result of analysis of the crystal structure of the photocatalyst film obtained by the conventional method for producing a photocatalyst film using XRD.

Specifically, the TiO ₂ powder was mixed with FeCl ₃ (TiO ₂ ) so that the Ti component of the rutile type titanium dioxide powder (TiO ₂ ) and the Fe component of the aqueous solution of iron chloride (FeCl ₃ ) were 99: The solution is stirred for 2 hours in the solution, and the Fe is supported on the TiO ₂ powder. Next, the solution was dried, pulverized and classified to obtain a particle size of about 100 mu m. Next, the photocatalyst coating film was formed by spraying using the water slurry of the prepared powder (concentration: 30% by weight), and the resultant crystal structure of the photocatalyst coating film thus obtained was analyzed by XRD. The production method of such a photocatalyst coating film is referred to as &quot; total charge method &quot; for the sake of convenience.

However, titanium dioxide (TiO ₂ ) is previously immersed in an aqueous solution of iron chloride (FeCl ₃ ) which is a sensitizer, that is, a sensitizer, and is stirred to carry iron or iron compound to titanium dioxide, The photocatalytic composition of the present invention requires a long period of time for the treatment, and in some cases, the drying process may be carried out. It is considered that there is a high possibility that the coagulation, growth and segregation of iron or iron compounds carried on the surface of titanium dioxide occur.

On the other hand, in the present invention, since the water slurry in which the sensitizer and the antimicrobial metal compound are dissolved at the molecular level is instantaneously fixed to the titanium dioxide surface by spraying, the sensitizer and the antimicrobial metal compound are dispersed in the nano- .

Therefore, the sensitizer and the antimicrobial metal compound of the present invention are excellent in dispersibility as compared with the prior art, and therefore, it is considered that the antimicrobial effect and the increase / decrease effect exceeding expectations can be obtained.

Here, in the results shown in Figure 4, it is possible to observe both the peaks of the FeO (OH) and Fe ₂ O _3, FeO (OH) contributing to the photocatalytic visible light screen is oxidized by the heat at the time of spraying, the visible screen And Fe ₂ O ₃ that does not contribute to Fe ₂ O ₃ .

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. In addition, since the ratio of Fe ₂ O ₃ is high, the visible light responsiveness becomes insufficient.

Here, electron microscopic photographs of the photocatalyst film obtained by the method of the present invention, SEM-EDS, elemental composition analysis and elemental distribution analysis were confirmed. This is believed to be due to the influence of FeCl ₃ used for Fe loading. That is, it is considered that Cl is formed in a state in which Cl does not volatilize due to the thermal spraying during the impregnation, and the photocatalytic property of the photocatalyst coating may be deteriorated due to contamination of such impurities. The results of the EDS analysis of the photocatalyst film obtained by the exclusive method are shown in Table 2 (a).

Fig. 5 shows the result of analysis of the crystal structure of the photocatalyst film obtained by supporting iron after forming the titanium dioxide film using XRD.

Specifically, a TiO ₂ film was formed by spraying using an aqueous slurry of rutile type titanium dioxide powder (TiO ₂ ) (concentration: 30 wt%), and the film thus formed was mixed with FeCl 3 ₃ solution for 2 hours to support Fe on the TiO ₂ coating. The result of the crystal structure analysis of the thus obtained photocatalyst coating film by XRD is shown in Fig. The production method of such a photocatalyst coating film is referred to as &quot; post-deposition method &quot; for convenience.

Also, in the results shown in Fig. 5, peaks of Fe ₂ O ₃ were not observed. This is because FeO (OH) does not receive the thermal effect by spraying.

As a result of the electron microscopic photographs of the photocatalyst film obtained by the post mortem method, and the analysis of the elements of the elements and the distribution of the elements, the ratio of Ti and Fe was higher than that of the photocatalyst film obtained by the present invention and the full- It can be seen that it is high. This is probably due to Fe segregation on the analytical surface due to the characteristic of the post-deposition method in which Fe is supported on the surface of the coating. In such a case, there is a fear that the lifetime of the visible light response characteristic is short because Fe is not present in the film when the film is worn out. The results of the EDS analysis of the photocatalytic film obtained by the post mortem method are shown in Table 2c.

As is clear from the above, in the case of the dedicated method, (1) a long time is required until the iron deposition is carried out, (2) the visible light response is poor due to the low proportion of FeO (OH) There is a concern that the solution has an adverse effect. In the case of the post-deposition method, Fe is segregated on the surface, and there is a concern that the lifetime of visible light responsiveness is short.

On the other hand, in the photocatalytic coating obtained by the method for producing a photocatalyst coating to which the present invention is applied, such a problem does not occur, the visible light responsiveness is excellent, and the visible light responsiveness is lengthened.

In addition, in the method for producing a photocatalytic film to which the present invention is applied, titanium dioxide powder having a rutile crystal structure is used inexpensively as compared with anatase crystal structure, thereby realizing cost reduction.

Here, the gas decomposition performance test of the photocatalytic coating film was carried out.

Fig. 6 shows a conceptual diagram of the evaluation test method. The test piece of the thermal spray film used for evaluation was about 50 mm square, and ceramic tiles were used as the substrate. The surface of the test piece was preliminarily cleaned with alcohol and irradiated with ultraviolet light (ultraviolet ray intensity: 1 mW / cm ² ) for 12 hours, and used for evaluation of gas decomposition.

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

The sample subjected to the test is a photocatalyst film obtained by the method for producing the photocatalyst film to which the present invention is applied and a photocatalytic film obtained by the post-treatment method. For comparison, the test was also conducted on a commercially available photocatalytic tile and a sulfur-doped titanium oxide thermal spray coating which is a visible light type photocatalyst.

The acetaldehyde gas decomposition test results of the respective coatings are shown in Fig. 7 and Fig.

It can be seen from FIGS. 7 and 8 that the photocatalytic coating obtained by the method for producing a photocatalytic coating according to the present invention exhibits a high acetaldehyde gas decomposition activity. In addition, about 2 times as much of acetaldehyde as that of carbon dioxide can be seen, and it is considered that complete decomposition is achieved.

On the other hand, the photocatalytic film obtained by the post mortem method exhibited the same gas removal performance as compared with the sulfur doped titanium oxide. However, the amount of generated carbon dioxide was smaller than that of the photocatalyst film obtained by the method of manufacturing the photocatalyst coating according to the present invention, and there was a stain smell which was considered as an intermediate product after the test. Therefore, it is presumed that the gas decomposition reaction in this case was not complete.

The results of the gas decomposition test conducted on the commercially available photocatalytic tile showed a considerably low decomposition activity as compared with the photocatalytic film obtained by the method for producing the photocatalytic film to which the present invention was applied.

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

Fig. 9 shows a conceptual diagram of the evaluation test method. The test piece of the thermal spray film used in the evaluation was about 50 mm square, and ceramic tiles were used for the substrate. The test pieces were subjected to an antimicrobial evaluation test by pretreating the surface with acetone and irradiating with ultraviolet light (ultraviolet intensity: 1 mW / cm ² ) for 6 hours.

Each of the samples was placed in a chalet (diameter 90 mm), 30 ml of Escherichia coli suspension was added, and the mixture was allowed to stand at 30 占 폚 under irradiation condition (illumination: 1700 lux) with a fluorescent lamp. Were measured with time. The number of bacteria was measured by a colony count method.

The evaluated samples are a photocatalyst film obtained by the method for producing a photocatalyst film to which the present invention is applied, a sulfur-doped titanium oxide film, and a commercially available photocatalytic tile. The evaluation test results are shown in Fig.

10 shows that the photocatalytic film obtained by the method of manufacturing the photocatalyst film according to the present invention exhibits a high sterilization characteristic, that is, sterilizing power against E. coli is reduced to 4 orders of 30 minutes and sterilization of all bacteria of 6 to 180 minutes. This does not reach the sterilizing power of 30 minutes to 6 orders, which was found in sulfur dioxide titanium oxide, but it can be said that it has sufficient performance for practical use. In addition, commercially available photocatalytic tiles had a low performance in which the number of living cells was hardly reduced even when compared with the blank.

<2. Modification Example 1>

In the method for producing a photocatalyst film according to the present invention, a water slurry is produced using a rutile type titanium dioxide powder and an aqueous solution of iron chloride, but an aqueous slurry using an anatase type titanium dioxide powder and an aqueous solution of iron chloride may be produced. Specifically, for example, an aqueous slurry using an anatase type titanium dioxide powder having a particle size of about 10 nm and an aqueous solution of iron chloride may be produced. At this time, in the water slurry, the anatase type titanium dioxide powder agglomerates to have a particle size of about 1 to 5 mu m.

However, in an anatase type titanium dioxide powder, it is difficult for the excited electrons excited in visible light to exceed the bandgap, and since the visible light responsiveness is hard to come out, the thermal spraying temperature is changed to a rutile crystal structure And then coated on the object. Specifically, it is necessary to form the photocatalyst film by setting the flame (frame) temperature to a high temperature of 2000 ° C or higher, and changing the crystal structure of the titanium dioxide powder to rutile type by heat during spraying. Therefore, in the case of supporting FeO (OH), it is preferable to use rutile type titanium oxide from the beginning without using expensive expensive anatase type titanium oxide.

<3. Modification Example 2>

In the method for producing a photocatalyst film according to the present invention, a visible light-responsive catalyst coating is realized by supporting FeO (OH), which exhibits a visible light response function, on a rutile titanium dioxide powder.

However, it is not necessary that the catalyst is supported on the photocatalyst particles, but it may be Fe ₂ O ₃ or the like which exhibits a promoter function.

Specifically, for example, an aqueous slurry of anatase type titanium dioxide powder having a particle size of about 10 nm and an aqueous iron oxide solution is produced (in this case, the titanium dioxide powder of anatase type aggregates in a water slurry, ), And an anatase type titanium dioxide on which Fe ₂ O ₃ is supported, which has a promoter function, is sprayed using the resulting water slurry to form a photocatalyst film.

In this case, the spraying temperature condition is a chlorination (frame) temperature of 300 to 2000 ° C. and a spraying speed of 800 to 2000 m / sec.

In addition, the anatase type titanium dioxide can exhibit a higher catalytic activity than the rutile type titanium dioxide.

<4. About donation>

In one example of the method for producing a photocatalytic film to which the present invention is applied, a titanium dioxide film on which at least one form of iron oxide, hydroxide, and oxyhydroxide is supported by spraying using a water slurry using titanium dioxide powder and an aqueous solution of iron chloride It is also possible to form a titanium dioxide film carrying not only iron but also at least one type of oxide, hydroxide or oxyhydroxide.

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₎ (Concentration 30% by weight) using a rutile type titanium dioxide powder, an aqueous solution of iron chloride and an aqueous solution of silver nitrate such that the Ti component of the silver nitrate solution and the Ag component of the silver nitrate silver solution (AgNO ₃ ) were in a weight ratio of 99: And the photocatalyst film may be formed by spraying using the resulting slurry of water.

By depositing silver oxide (AgO ₂ ), which is a kind of antimicrobial metal, on the rutile type titanium dioxide film having a visible light response function and a cocatalytic function, it is possible to add a very high antibacterial function to the photocatalytic film, , Food processing factories, etc., it is effective to prevent infectious diseases and food poisoning by applying to flooring materials, wall materials, ceiling materials and other facilities in sanitary facilities.

It can be seen that the nano-sized silver oxide is not segregated and dispersed substantially uniformly in the result of the surface observation (not shown) of the photocatalyst film obtained by the above-mentioned method of producing the photocatalyst film using SEM-EDS. 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 of the photocatalyst coating film obtained by the exclusive method was performed using SEM-EDS.

Specifically, TiO ₂ powder was stirred for 2 hours in a FeCl ₃ solution such that the Ti component of the titanium dioxide powder (TiO ₂ ) and the Fe component of the aqueous solution of iron chloride (FeCl ₃ ) were in a weight ratio of 99.7: 0.3, 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, pulverized and classified into particle diameters to match particle sizes. Subsequently, a photocatalyst film was formed by spraying using the water slurry of the powder thus prepared (concentration: 30 wt%), and the surface of the photocatalyst film thus obtained was observed with SEM-EDS.

As a result, it was found that silver segregation of 3 탆 or more was present. Further, when silver is segregated, the photocatalytic function and the antibacterial effect vary depending on the place, and the performance of the photocatalytic film becomes unstable.

Further, the surface of the photocatalyst film obtained by the post mortem method was observed using SEM-EDS.

Specifically, spraying was performed using an aqueous slurry of titanium dioxide powder (TiO ₂ ) (concentration: 30% by weight) to prepare TiO ₂ And the film thus formed was immersed in a FeCl ₃ solution for 2 hours to have a weight ratio of Ti: Fe = 99.7: 0.3, thereby supporting Fe on the TiO ₂ film. Subsequently, the substrate was immersed in an aqueous solution of silver nitrate so as to have a weight ratio of Ti: Ag = 99: 1, and ultraviolet rays were irradiated to carry Ag on the TiO ₂ coating, and the surface of the thus obtained photocatalyst coating film was observed with SEM-EDS. Figs. 11 and 12 show the gas decomposition test results and the sterilization test results using this film.

As a result, it was found that silver segregation of 3 탆 or more was present. Further, if silver becomes segregated, the photocatalytic function and the antibacterial effect are changed depending on the place, and the performance of the photocatalytic coating becomes unstable.

Further, the presence of thick silver segregation can be confirmed on the surface layer of the coating film, and the photocatalytic performance in which the light intensity reaching titanium dioxide is lowered due to the silver segregation of the surface layer is likely to deteriorate.

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

<5. About carrying of pigment>

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

A water slurry (concentration of 30% by weight) was prepared so that the Ti component of the titanium dioxide powder (TiO ₂ ) and the pigment (component mica (muscovite), TiO ₂ and Fe ₂ O ₃ ) ), And the result of analysis of the crystal structure by XRD of the photocatalyst film formed by spraying using the resulting water slurry is shown in Fig.

It can be confirmed from the results shown in Fig. 13 that the peak of Fe ₂ O ₃ is small and the adhesion ratio of the pigment is low.

Here, in the electron microscope photographs of the photocatalytic coatings obtained by the above-mentioned method, SEM-EDS photographs, elemental analysis of elements and distribution of elemental analysis (not shown), the yields of the pigments Was low.

Fig. 14 shows the results of analysis of the crystal structure of the photocatalyst film obtained by the X-ray diffraction method using XRD.

Specifically, the two powders were mixed so that the Ti component of the titanium dioxide powder (TiO ₂ ) and the pigment were in a weight ratio of Ti: pigment = 7: 3, and the pellets were fired at 1200 ° C for 30 minutes. To achieve a particle size of about 100 mu m. Next, a photocatalyst was formed by spraying using the water slurry of the powder thus prepared (concentration: 30% by weight), and the resultant crystal structure of the photocatalyst film thus obtained was analyzed by XRD.

In the results shown in Fig. 14, it can be seen that the peak of Fe ₂ O ₃ , which is a component of the pigment, is large and a lot of pigments are attached.

Here, the photomicrograph of SEM-EDS of the photocatalytic coating film obtained by the above-mentioned method and the result of elemental analysis of element and distribution of elemental analysis (not shown) showed that the pigment component Fe contained about 16% of Ti The yield was high. This is considered to be due to the increase in the mass of the particles due to the composite of the pigment and TiO ₂ .

15 shows the results of the analysis of the crystal structure of the photocatalyst film obtained by the post-deposition method using XRD.

More specifically, a TiO ₂ film is formed by spraying using an aqueous slurry of titanium dioxide powder (TiO ₂ ) (concentration: 30 wt%). Next, the crystal structure of the composite coating film of TiO ₂ and pigment obtained by applying the pigment to a TiO ₂ coating as a water slurry (concentration 30% by weight) and firing at 1250 ° C for 1 hour was analyzed by XRD, to be.

In the results shown in Fig. 15, it is considered that the peak of TiO ₂ is lost, and the surface is covered with the pigment at the penetration depth of X-ray or more.

Here, the electron microscopic photographs of the photocatalyst coating film obtained by the above-mentioned post mortar method and the results of elemental analysis of elements and distribution of elements (not shown) result in a very low Ti ratio, Was completely covered. There is a fear that the photocatalytic function, in which light intensity reaching titanium dioxide is lowered due to such a pigment, is lowered.

Claims (9)

A step of forming a slurry containing water, at least one kind of compound selected from water-soluble metal complexes of Fe, Cu, Cr and Ni, or water-soluble metal salt, and water;
The slurry is sprayed so that the anions of at least one kind of the compound are volatilized by the thermal spray and the metal ions of the compound react with the water of the slurry so that at least one of the hydroxides or oxyhydroxides of Fe, And at least one kind of an oxide of Fe, Cu, Cr, or Ni produced together with the hydroxide or the oxyhydroxide is carried on the photocatalyst particles in the slurry, and the photocatalyst particles And a step of laminating on the object
A method for producing a photocatalyst coating film. The method according to claim 1,
The hydroxides, oxyhydroxides or oxides of Fe, Cu, Cr and Ni exhibit a visible light responsive function and a cocatalyst function
A method for producing a photocatalyst coating film. The method according to claim 1,
When the photocatalyst particles are rutile titanium dioxide particles
A method for producing a photocatalyst coating film. 3. The method of claim 2,
When the photocatalyst particles are rutile titanium dioxide particles
A method for producing a photocatalyst coating film. 5. The method according to any one of claims 1 to 4,
An antimicrobial metal, an antimicrobial metal salt or an antimicrobial metal complex to form the slurry,
The slurry is sprayed and the antimicrobial metal, the antibacterial metal salt or the antibacterial metal complex together with the photocatalyst particles are laminated on the object in at least one form selected from metal, metal salt, metal complex, oxyhydroxide, hydroxide or oxide
A method for producing a photocatalyst coating film. 5. The method according to any one of claims 1 to 4,
Forming a slurry containing the pigment,
The slurry is sprayed to deposit the pigment together with the photocatalyst particles on the object
A method for producing a photocatalyst coating film. 5. The method according to any one of claims 1 to 4,
Forming a slurry containing an adsorbent material,
The slurry is sprayed, and the photocatalyst particles and the adsorbent are laminated on the object
A method for producing a photocatalyst coating film. A water-soluble metal complex of Fe, Cu, Cr, or Ni, or a water-soluble metal salt, and water,
The slurry is sprayed so that the anions of at least one kind of the compound are volatilized by the thermal spray and the metal ions of the compound react with the water of the slurry so that at least one of the hydroxides or oxyhydroxides of Fe, And at least one type of an oxide of Fe, Cu, Cr, or Ni produced together with the hydroxide or the oxyhydroxide is supported on the photocatalyst particles in the slurry, and the photocatalyst particles are laminated on the object Manufactured
Photocatalytic coating. delete

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