JP2016161507A - Hydrogen gas sensitive film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen gas sensitive film having favorable hydrogen gas sensitivity and a method of manufacturing the same.SOLUTION: A hydrogen gas sensitive film includes a catalyst layer on a lighting control layer made of tungsten oxide. The lighting control layer includes an irregular continuous hole to the boundary of the catalyst layer by detaching an internally generated object. Its manufacturing method includes: a base layer formation process for applying solution that is prepared by mixing halogenation tungsten with alcohol whose carbon number is 1 to 4 on a substrate to dry it; a protection layer formation process for applying solution prepared by mixing a platinum group metallic compound with organic solvent thereon; and an ultraviolent processing process in which by irradiating ultraviolet under reductive gas atmosphere, the halogenation tungsten is turned into tungsten oxide and the platinum group metal compound is turned into a platinum group metal.SELECTED DRAWING: Figure 2

Description

The present invention relates to a hydrogen gas sensitive film that is sensitive to atmospheric hydrogen (H ₂ ) gas and a method for manufacturing the same, and more particularly to a hydrogen gas sensitive film that provides dimming property that changes light transmittance by controlling the atmospheric gas and the method thereof. It relates to a manufacturing method.

  There is known a light control glass provided with a light control film that controls inflow and outflow of light and heat. There are three types of light control glass according to the drive method of the light control film: (1) an electrochromic method that reversibly changes the light transmittance by applying current and voltage; There are a thermochromic method for changing the transmittance, and (3) a gaschromic method for changing the light transmittance by controlling the atmospheric gas. Among these methods, light control glass by an electrochromic method using a tungsten oxide film as the light control layer of the light control film is considered to be closest to the practical stage. However, the formation of the light control film for this method requires a complicated multilayer coating process, which is very expensive and hinders its spread. On the other hand, the gas chromic method is more advantageous in terms of cost because a simple structure in which a catalyst is supported on a light control layer can be used as a light control film.

  As a gaschromic light control film, a hydrogen gas sensitive film made of a tungsten oxide film provided with a catalyst made of platinum or palladium responding to hydrogen gas can be used (see Patent Document 1, Non-Patent Documents 1 to 7). . Such a light control film can be generally produced by a method such as a sputtering method or a pulse laser deposition method, which is one of physical vapor deposition methods.

  On the other hand, a method for producing the above-described hydrogen gas sensitive film by a cheaper wet method has also been proposed (see Patent Documents 2 to 6). On the other hand, the wet method requires a step of applying a precursor solution to a substrate and then baking it at a high temperature to burn the hydrogen gas sensitive film, but it has low heat resistance against heating in the baking step. It is also pointed out that it is difficult to use a substrate. Therefore, for example, Patent Document 7 discloses a method of obtaining a hydrogen gas sensitive film by reducing the precursor solution applied to the substrate by irradiating ultraviolet rays instead of the baking treatment.

Japanese Patent No. 63-51501 Japanese Patent No. 3781354 JP 2005-331364 A JP 2005-345338 A JP 2007-71866 A JP 2007-170946 A JP 2010-2346 A

J. Alloys and Compounds, 446-447, 558-561, 2007. Nuclear Instruments and Methods in Physics Research B, 266, 301-307, 2008. Sensors and Actuators B: Chemical, 145, 691-697, 2010. Sensors and Actuators B: Chemical, 157, 504-509, 2011. Solar Energy Materials & Solar Cells, 95, 2335-2340, 2011. Sensors and Actuators B: Chemical, 169, 284-290, 2012. Appl. Surf. Sci., 273, 261-267, 2013.

  In a hydrogen gas-sensitive film by a wet method in which platinum / palladium that functions as a catalyst is deposited and dispersed in a tungsten oxide film as metal particles, the metal particles do not necessarily exist only on the surface of the tungsten oxide film and are buried in the film. Therefore, the catalytic activity cannot be expressed efficiently. Even if the metal fine particles can be concentrated on the surface of the tungsten oxide film, if the tungsten oxide film is deteriorated by the external environment, the resulting hydrogen gas sensitive film has good hydrogen gas sensitivity. It cannot be maintained.

  This invention is made | formed in view of the above situations, Comprising: The objective is to provide the hydrogen gas sensitive film | membrane which has favorable hydrogen gas sensitivity, and its manufacturing method.

  The hydrogen gas-sensitive film according to the present invention is a hydrogen gas-sensitive film in which a catalyst layer is provided on a light control layer made of tungsten oxide, and the hydrogen gas-sensitive film is not exposed to the catalyst layer boundary due to desorption of internal products. The light control layer has regular communication holes.

  According to this invention, the catalyst layer can be a protective film that suppresses deterioration of the light control layer due to the external environment, and hydrogen gas can be quickly guided to the inside of the light control layer by the irregular communication holes, resulting in good results. It is sensitive to hydrogen gas.

  The method for producing a hydrogen gas-sensitive film according to the present invention is a method for producing a hydrogen gas-sensitive film in which a catalyst layer is provided on a light control layer made of tungsten oxide. A base layer forming step of applying a solution prepared by mixing alcohol 4 to a substrate and drying it, and forming a protective layer by applying a solution prepared by mixing a platinum group metal compound and an organic solvent thereon And an ultraviolet treatment step of irradiating ultraviolet rays in a reducing gas atmosphere to convert the tungsten halide into tungsten oxide and the platinum group metal compound into a platinum group metal.

  According to such an invention, a hydrogen gas sensitive film in which a catalyst layer is provided on a light control layer made of tungsten oxide, the irregular communication hole to the catalyst layer boundary due to the elimination of internal organic matter and halide Is provided in the light control layer, and as a result, it can achieve good hydrogen gas sensitivity.

  In the above-described invention, the ultraviolet treatment step may be characterized in that the light control layer is provided with irregular communication holes to the catalyst layer boundary due to the elimination of the alcohol, the organic matter derived from the tungsten halide, and the halide. . According to this invention, the hydrogen gas sensitive film which can guide hydrogen gas quickly to the inside of the light control layer can be obtained by the irregular communication hole, and this can achieve better hydrogen gas sensitivity.

In the above invention, the tungsten halide is tungsten hexachloride, and the platinum group metal compound is hexachloroplatinic acid, bis (acetylacetonato) platinum (Pt (acac) ₂ ), palladium dichloride, bis (acetyl). Any one of acetonato) palladium (Pd (acac) ₂ ) may be included. According to this invention, a hydrogen gas sensitive film having better hydrogen gas sensitivity can be provided relatively easily.

  In the above-described invention, the alcohol may be one or more of methanol, ethanol, n-propyl alcohol, and i-propyl alcohol. According to this invention, a hydrogen gas sensitive film having better hydrogen gas sensitivity can be provided relatively easily.

  In the above invention, the alcohol may be a mixture of ethanol and i-propyl alcohol in a volume ratio of 2 to 6 times. According to this invention, a hydrogen gas sensitive film having better hydrogen gas sensitivity can be provided relatively easily.

  In the above-described invention, the organic solvent may be ethylene glycol monomethyl ether and / or ethanol. According to this invention, a hydrogen gas sensitive film having better hydrogen gas sensitivity can be provided relatively easily.

  In the above-described invention, the mixing of the tungsten halide and the alcohol may be performed in an inert gas atmosphere having an oxygen concentration of at least 1% by volume or less. According to this invention, a hydrogen gas sensitive film having better hydrogen gas sensitivity can be provided relatively easily.

  In the above-described invention, the base layer forming step may be characterized by forming a film in an amorphous phase. According to this invention, a hydrogen gas sensitive film having better hydrogen gas sensitivity can be provided relatively easily.

  In the above-described invention, the reducing gas atmosphere may be a hydrogen gas atmosphere. According to this invention, a hydrogen gas sensitive film having good hydrogen gas sensitivity can be provided relatively easily.

It is sectional drawing of the hydrogen gas sensitive film | membrane by this invention. It is a flowchart of the manufacturing method of the hydrogen gas sensitive film | membrane by this invention. It is sectional drawing of the apparatus used at an ultraviolet treatment process. It is sectional drawing of the measuring apparatus which measures a laser beam transmittance. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 1. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 2. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 3. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 4. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 5. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 6. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 7. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 8. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 9. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 10. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 11. It is a figure which shows the time-dependent change of the laser beam transmittance in Example 12. It is a figure which shows the time-dependent change of the laser beam transmittance in the comparative example 2. It is a figure which shows the time-dependent change of the laser beam transmittance in the comparative example 3. It is a figure which shows the time-dependent change of the laser beam transmittance in the comparative example 4. It is a figure which shows the time-dependent change of the laser beam transmittance in the comparative example 5.

  The hydrogen gas sensitive membrane according to the present invention will be described in detail with reference to FIG.

  As shown in FIG. 1, the hydrogen gas sensitive film 1 includes a light control layer 2 made of tungsten oxide and a catalyst layer 3. The light control layer 2 is disposed on the substrate 4 and has a so-called hydrogen gas chromic characteristic in which light transmittance is changed by tungsten oxide in response to hydrogen gas. The catalyst layer 3 is made of a platinum group metal disposed on the light control layer 2.

  Here, the light control layer 2 has irregular communication holes up to the boundary with the catalyst layer 3 therein, and is a so-called porous body. Such irregular communication holes extend in irregular directions and are obtained due to the manufacturing method described later. Thus, the light control layer 2 made porous can introduce | transduce hydrogen gas to the inside. Thereby, the hydrogen gas sensitive film | membrane 1 obtains a high reaction rate with respect to hydrogen gas, and has favorable hydrogen gas sensitivity.

  Next, the manufacturing method of the hydrogen gas sensitive film | membrane 1 is demonstrated in detail using FIG. 3 along FIG.

  As shown in FIG. 2, in the base layer formation (S1) for forming the base layer for obtaining the light control layer 2, a step (S1-1) of preparing a tungsten-containing solution and a step of applying a tungsten-containing solution (S1-2) And a drying step (S1-3) in which the applied solution is dried to form a film as a base layer.

  In preparation of the solution (S1-1), alcohol having 1 to 4 carbon atoms, so-called lower alcohol, is mixed with tungsten halide.

  Tungsten halide is represented by the general formula WXa. X is a halogen such as chlorine or bromine, and a is an integer of 2 to 6. Specific examples of the tungsten halide include tungsten trichloride, tungsten tetrachloride, tungsten pentachloride, tungsten hexachloride, tungsten pentabromide, tungsten hexabromide, and the like. From the viewpoint of easy availability, tungsten hexachloride can be suitably used.

  As the lower alcohol having 1 to 4 carbon atoms, monovalent lower alcohols are preferable, and alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propyl alcohol, i-propyl alcohol and the like are more preferable. It is. A lower alcohol may be used individually by 1 type, or multiple types may be mixed and used for it. When one kind is used alone, methanol and ethanol are preferable from the viewpoint of reactivity, and i-propyl alcohol and n-propyl alcohol are preferable from the viewpoint of stability of the solution. When mixing two types, for example, it can be used in a volume ratio of ethanol: i-propyl alcohol = 1 to 10:10 to 1, but in particular ethanol: i-propyl alcohol = 2. It is preferably used in a ratio of 6: 1. In addition, when using several alcohol, it is preferable to dripped in order from alcohol with a small carbon number in view of the reaction rate at the time of mixing.

  The tungsten-containing solution is prepared by mixing the above-described tungsten halide and lower alcohol. Increasing the concentration of the tungsten-containing solution can reduce the number of film formations to obtain the required film thickness for the light control layer, but if it is too high, the resulting light control layer is a layer with a grayish tint and is transparent. It is not preferable because a hydrogen gas sensitive film cannot be produced. On the other hand, when the concentration is low, the number of times of film formation for obtaining a required film thickness increases. For this reason, the density | concentration which makes tungsten 0.1-0.5 mol / L is suitable. Furthermore, it is preferable to prepare a tungsten-containing solution in a colorless and transparent manner because a transparent hydrogen gas sensitive film having a high initial transmittance can be produced.

  The tungsten-containing solution is preferably prepared in an inert gas such as nitrogen or argon which is dried so that the oxygen concentration is 1% by volume or less and the dew point temperature is −80 ° C. or less. When the oxygen concentration exceeds 1% by volume, the reaction between the tungsten halide and the lower alcohol does not proceed well, and it is difficult to develop gaschromic properties in the film on the substrate 4 finally obtained. The durability of the light control layer obtained from the above will be reduced.

  In mixing, tungsten halide may be added to the alcohol. However, a method of adding alcohol to tungsten halide is preferable in view of the fact that mixing involves a severe exothermic reaction and workability. In addition, in order to suppress the temperature rise accompanying heat generation, alcohol is added little by little under ice cooling. In addition, if water is mixed in the reaction solution, a hydrolysis reaction will occur and precipitation will occur, so the alcohol will be dehydrated and used, and a desiccant such as silica gel will be placed at the end of the open trap when mixing. Thus, it is preferable to prevent the mixing of moisture in the atmosphere.

  After adding the alcohol, a colored solution is produced. Although it differs from yellow, orange, green, blue, etc. depending on the type of solvent, etc., stirring is continued and in each case, the reaction is continued until the color of the solution is changed to almost colorless and transparent. The reaction time depends on the type of solvent, the concentration of the solution, room temperature, etc., and is about 1 week to 1 month.

  In the application of the solution (S1-2), the prepared tungsten-containing solution is applied onto the substrate 4. As a coating method, a spin coating method, a dip coating method, a printing method, and the like are exemplified as suitable ones. However, the application method is not limited to these. Can do. As the substrate 4, glass, a polymer substrate, or the like can be used. The substrate 4 is previously removed from moisture and dirt. For example, when glass is used as the substrate 4, it is preferably washed with a saturated potassium hydroxide ethanol solution, distilled water or the like and fired immediately before use.

  In drying (S1-3), unreacted alcohol is removed from the applied tungsten-containing solution to form a film as a base layer, but it is preferable to form the film in an amorphous phase without crystallizing. Thereby, in the hydrogen gas sensitive film 1 finally obtained, good hydrogen gas sensitivity, particularly hydrogen gas chromic characteristics can be obtained. If the heat treatment is performed at a relatively high temperature, particularly over 300 ° C., the gas chromic characteristics can be deteriorated in the hydrogen gas sensitive film 1 obtained by crystallization and densification of the film formed as the base layer. Moreover, even if it is made to dry at low temperature, especially less than 20 degreeC, the durability and gaschromic characteristic of the film | membrane obtained may become inadequate. Therefore, typically, drying is performed at room temperature to 300 ° C. for about 1 minute to 1 hour, and preferably a substrate having relatively low heat resistance can be used as long as the drying is performed by heat treatment at 100 ° C. for about 10 minutes. .

  The gas chromic characteristics also depend on the thickness of the light control layer 2 to be obtained, that is, the thickness of the base layer. This film thickness is preferably 100 nm to 2 μm, more preferably 300 nm to 1 μm. By repeating the steps of coating (S1-2) and drying (S1-3), the film thickness can be adjusted to a desired value. As the film is thicker, gas chromic characteristics tend to appear larger. However, if the film is too thick, not only does it take longer to form the film, but also the response speed to the gas decreases. On the other hand, if it is too thin, the gaschromic characteristics may be insufficient.

  Next, a protective layer made of a solution of a metal compound of a metal serving as a catalyst is formed on the surface of the formed base layer (S2). The formation of the protective layer includes a step (S2-2) of applying the solution through a solution preparation step (S2-1).

In the preparation of the solution (S2-1), a platinum group metal compound and an organic solvent are mixed to prepare a platinum group metal-containing solution. Examples of the platinum group metal include platinum and palladium, and two or more kinds may be used. Platinum group metal compounds include bis (acetylacetonato) platinum (II) (Pt (acac) ₂ ), bis (acetylacetonato) palladium (II) (Pd (acac) ₂ ), platinum chloride (IV) (PtCl ₄ ), palladium chloride (II) (PdCl ₂ ), hexachloroplatinic acid (H ₂ PtCl ₆ ) and the like.

  The organic solvent to be used may be any solvent that can dissolve the platinum group metal compound, and examples thereof include ethylene glycol monomethyl ether and ethanol. Among them, ethylene glycol monomethyl ether having good solubility and good stability of the platinum group metal-containing solution is exemplified as a preferable one. Depending on the platinum group metal compound, a dissolution aid such as hydrochloric acid can be added to the solvent in order to increase the solubility.

  The above platinum group metal compound is added to these organic solvents and stirred to prepare a solution. The preparation is preferably performed at room temperature to 80 ° C. or less. If it exceeds 80 ° C., a precipitate may be formed in the solution. The concentration of the solution is preferably set within a range where the platinum group metal compound can be uniformly dissolved in the solvent. When a palladium compound is used, a concentration of about 0.01 mol / L is preferred, and when a platinum compound is used, a concentration of about 0.01 to 0.02 mol / L is exemplified as a suitable one.

  Further, in the preparation of the solution (S2-1), special atmosphere control is not usually required, but it is preferably performed in a dry inert gas such as nitrogen or argon in order to protect the underlying base layer. .

  Furthermore, in the preparation of the solution (S2-1), the solubility varies depending on the type of platinum group metal compound, the type of organic solvent, and the concentration of the platinum group metal compound, so it is prepared according to the concentration of the solution to be obtained. It is preferable to appropriately set the temperature of the platinum group metal compound and dissolve the platinum group metal compound uniformly.

  For example, when bis (acetylacetonato) palladium (II) and ethylene glycol monomethyl ether are prepared at a concentration of 0.01 mol / L, they are not completely dissolved at room temperature, and then at 60 ° C. for 10 minutes, further 70 Dissolve completely by heating at 10 ° C. for 10 minutes. Heat treatment at 60 ° C. alone is not completely dissolved. On the other hand, heating and refluxing at a temperature in the vicinity of the boiling point (130 ° C.) of the solvent generates black precipitates.

  On the other hand, when bis (acetylacetonato) platinum (II) and ethylene glycol monomethyl ether are prepared at a concentration of 0.01 mol / L, they are completely dissolved by stirring at room temperature to form a uniform solution. When the concentration is increased to 0.02 mol / L, it is not completely dissolved at room temperature. Therefore, it is completely dissolved by heating at 60 ° C. for 10 minutes.

  Next, the prepared solution is applied on the base layer (S2-2) to form a protective layer. As the coating method, a spin coating method, a dip coating method, a printing method, and the like are exemplified as suitable ones. Can be used.

  Next, referring also to FIG. 3, the precursor 1 ′ of the hydrogen gas sensitive film 1 comprising a base layer formed on the substrate 4 and a protective layer made of a platinum group metal-containing solution applied thereto is treated with ultraviolet light. As (S3), ultraviolet rays are irradiated in a reducing gas atmosphere to reduce the platinum group metal compound in the protective layer to a platinum group metal. In addition, by the ultraviolet treatment, the tungsten halide that is a reaction product with the lower alcohol in the tungsten-containing solution is converted into tungsten oxide in the base layer. Here, a glass cell 6 made of a substantially flat plate is disposed so as to face the surface of the precursor 1 ′ formed on the substrate 4. A spacer 7 is provided on the surface of the glass cell 6 on the precursor 1 ′ side, and a space for guiding the reducing gas to the surface of the precursor 1 ′ is provided. The glass cell 6 is connected to the mass flow controller 5 so that the reducing gas can be introduced at a predetermined flow rate. Here, a reducing gas having a predetermined flow rate is guided to the surface of the precursor 1 ′ by the glass cell 6 and is irradiated with ultraviolet rays from the light source 8 installed on the back side of the substrate 4. In this case, the substrate 4 is made of a material that transmits ultraviolet rays, and for example, soda glass can be used. In this way, the hydrogen gas sensitive film 1 is obtained by subjecting the precursor 1 ′ to ultraviolet treatment.

  The ultraviolet treatment (S3) is performed in the presence of a reducing gas such as hydrogen. The reducing gas may be diluted with an inert gas such as argon. Further, the ultraviolet treatment is preferably performed at room temperature, and it is particularly preferable not to perform the heat treatment before the ultraviolet irradiation. When hydrogen gas is used, the hydrogen gas concentration is not particularly limited, but the reaction takes time at a concentration of less than 2% by volume. On the other hand, at a concentration exceeding 8% by volume, the reaction can proceed efficiently and quickly, but there is a problem in safety. Moreover, when hydrogen gas concentration is made high, it is easy to produce | generate water on the surface, and may cause deterioration of the light control film obtained. Therefore, the reducing gas is preferably exemplified by argon gas containing hydrogen having a concentration of 2 to 8% by volume, particularly 3 to 6% by volume. Note that an organic solvent such as ethylene glycol monomethyl ether evaporates by irradiation with ultraviolet rays in the presence of a reducing gas and is released from the protective layer.

  In addition, you may irradiate an ultraviolet-ray from the precursor 1 'side instead of the back surface side of the board | substrate 4, In this case, two methods, the method of irradiating from the outer side of the glass cell 6, and the method of irradiating from the inner side, are used. obtain. In either case, the shape and material of the glass cell 6 are selected so that the precursor 1 ′ is irradiated with ultraviolet rays.

  As the ultraviolet light source 8, various light sources such as an ultrahigh pressure mercury lamp and a high pressure mercury lamp can be used. The wavelength of the ultraviolet light may be appropriately selected according to the ultraviolet transmittance of the substrate 4 or the glass cell 6 interposed between the light source and the precursor 1 ′. When a very general soda glass plate is used, a wavelength in the range of 290 to 380 nm, which is a wavelength region where the transmittance of soda glass is large, may be selected. The irradiation time of ultraviolet rays is usually 5 minutes to 1 hour, preferably 15 minutes to 30 minutes.

  Gaschromic properties also depend on the amount of platinum group metal. By repeating the steps of applying the platinum group metal-containing solution (S2-2) and ultraviolet treatment (S3), the desired amount of platinum group metal can be prepared. As the amount of platinum group metal in the resulting catalyst layer 3 increases, the change in light transmittance with respect to hydrogen gas can be increased as gas chromic characteristics, and the durability of the light control layer 2 is also improved by the effect as a protective film. There is a tendency. However, if the amount of platinum group metal is too large, the resulting hydrogen gas sensitive film has a blackish color, which reduces light transmittance and wastes valuable resources. When a platinum group metal-containing solution having a concentration of about 0.01 to 0.02 mol / L is used, a stack of about 1 to 5 layers is shown as a preferable example.

  Note that, before performing the ultraviolet treatment (S3), each element of tungsten, halogen (eg, chlorine), oxygen, carbon, and hydrogen was detected in the base layer. That is, it is considered that the base layer is left with an organic substance and a halide which are part of a reaction product of tungsten halide and lower alcohol. Such a halide is desorbed from the base layer together with the organic substance while contributing part of the halide ion to the reduction reaction of the platinum group metal ion in the ultraviolet treatment. The internal products of the desorbed organic substance and halide form a communicating hole extending in an irregular direction in the base layer by movement to the surface, and the light control layer 2 obtained from the base layer is made porous. Further, with the elimination of the internal product, tungsten oxide is generated in the base layer. Thereby, the light control layer 2 obtained after the ultraviolet treatment is given sensitivity to hydrogen gas, and the hydrogen gas sensitive film 1 is formed together with the catalyst layer 3 obtained from the protective layer. Here, in drying (S1-3), if the reaction product of tungsten halide and lower alcohol in the base layer is formed in an amorphous phase without crystallizing as described above, it is desorbed by ultraviolet treatment (S3). It is preferable because the starting point of the movement of the internal product can be made more random, and the formation of irregular communication holes can be promoted by facilitating the movement.

  In this way, the hydrogen gas sensitive film 1 carrying the platinum group metal formed as the catalyst layer 3 is formed on the light control layer 2 made of tungsten oxide. The hydrogen gas sensitive film 1 has hydrogen gas sensitivity, particularly hydrogen gas chromic characteristics. In particular, as described above, the light control layer 2 is made porous by irregular communication holes, and hydrogen gas can be guided into the light control layer 2. Thereby, the hydrogen gas sensitive film | membrane 1 obtains a high reaction rate with respect to hydrogen gas, and has favorable hydrogen gas sensitivity.

  Next, in order to confirm the hydrogen gas chromic characteristics of the hydrogen gas sensitive film 1 obtained by the above-described manufacturing method, the measurement results obtained by measuring the transmittance of laser light will be specifically described.

  First, the measurement apparatus 10 and measurement method used for measuring the transmittance of laser light will be described with reference to FIG.

  As shown in FIG. 4, the measuring apparatus 10 arranges a glass cell 6 made of a substantially flat plate so as to face the surface of the hydrogen gas sensitive film 1 formed on the substrate 4. A spacer 7 is provided on the surface of the glass cell 6 on the hydrogen gas sensitive film 1 side, and a space for guiding a hydrogen-containing gas composed of argon containing 4% by volume of hydrogen to the surface of the hydrogen gas sensitive film 1 is provided. . The glass cell 6 is connected to the mass flow controller 5 so that a predetermined amount of hydrogen-containing gas can be introduced. A semiconductor laser device 11 capable of irradiating a laser beam having a wavelength of 670 nm is provided on the back side of the substrate 4, and a photodiode 12 for detecting the laser beam transmitted through the substrate 4, the hydrogen gas sensitive film 1 and the glass cell 6 is also made of glass. It is provided on the back side of the cell 6.

  A hydrogen gas sensitive film according to each example described later manufactured by the manufacturing method described above, and a film corresponding to a hydrogen gas sensitive film according to each comparative example described below manufactured by changing a part of the manufacturing method. On the other hand, supply and stop of the hydrogen-containing gas at a flow rate of 100 ml / min were repeated every 60 seconds using the measuring device 10, and the transmittance of the laser beam to the hydrogen gas sensitive film and the corresponding film was measured. When the supply of the hydrogen-containing gas is stopped, the atmosphere is introduced to the surface of the hydrogen gas sensitive film 1 accordingly.

  Next, the details of the method of manufacturing the hydrogen gas sensitive film according to each example manufactured by the above-described manufacturing method and the measurement result of the transmittance of laser light will be described.

[Example 1]
In preparation of the tungsten-containing solution (S1-1), tungsten chloride (VI) (WCl ₆ , manufactured by Strem Chemicals) was placed in a three-necked flask under a dry nitrogen atmosphere with a dew point temperature of 1% by volume or less at −80 ° C. or less. ) Was measured, and a lower alcohol was added as a solvent so as to have a concentration of 0.25 mol / L. Super-dehydrated ethanol (Wako Pure Chemical Industries, for organic synthesis) and ultra-dehydrated i-propyl alcohol (Wako Pure Chemical Industries, for organic synthesis) are used as the solvent. In the order of propyl alcohol, the mixture was slowly added dropwise at a volume ratio of 4: 1 with stirring under ice cooling, and stirring was continued for 3 weeks at room temperature. Thereby, tungsten (VI) chloride was dissolved and reacted, and finally a colorless and transparent tungsten-containing solution was obtained.

  In the application of the solution (S1-2), this solution is spin-coated on the substrate under conditions of 3000 rpm and 30 s. Then, in the drying (S1-3), the solution is heated on a hot plate at 100 ° C. for 10 minutes and dried. It was. This coating and drying were repeated 5 times to form a base layer having a thickness of about 400 nm. The substrate used was a 30 mm × 30 mm × 1 mm flat glass plate, which was washed with a saturated potassium hydroxide ethanol solution and distilled water before use.

  In the preparation of the platinum group metal-containing solution (S2-1), bis (acetylacetonato) palladium (II) (manufactured by Wako Pure Chemical Industries, Ltd., for organic synthesis) was measured in an eggplant flask under a dry nitrogen atmosphere. To this was added ethylene glycol monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) to a concentration of 0.01 mol / L, and the mixture was stirred at room temperature for 10 minutes. Thereafter, the mixture was heated at 60 ° C. for 10 minutes, further heated at 70 ° C. for 10 minutes, and then stirred overnight at room temperature to obtain a palladium-containing solution as a platinum group metal-containing solution.

  In the application of the platinum group metal-containing solution (S2-2), the palladium-containing solution was spin-coated on the previously prepared base layer under the conditions of 3000 rpm and 30 s.

  In the ultraviolet treatment (S3), ultraviolet rays having a wavelength of 365 nm were irradiated for 15 minutes while flowing an argon gas containing 4% by volume of hydrogen as a reducing gas (see FIG. 3).

  The hydrogen gas sensitive film produced as described above was attached to the test apparatus 10 (see FIG. 4), and the transmittance of the laser beam was measured. The measurement results are shown in FIG.

Colorless and transparent (transparent state) to blue (colored state) corresponding to the stop (indicated as “H ₂ gas off” in the drawing) and supply (indicated as “H ₂ gas ON” in the drawing) of the hydrogen-containing gas As the color of the hydrogen gas sensitive film changed, the transmittance of the laser light changed in the range of 88 to 50%, and it was confirmed that the film was sensitive to hydrogen gas. As the response speed, when the hydrogen-containing gas is supplied, it gradually changes to a colored state over 60 seconds, but when the supply of the hydrogen-containing gas is stopped and the atmosphere is introduced, the original transparent state is obtained in about 10 seconds. I was able to confirm returning. Further, even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more, the width of the change in transmittance, that is, the response width was not significantly reduced. That is, good durability of the hydrogen gas sensitive film was confirmed.

[Example 2]
A base layer having a thickness of about 400 nm was formed in the same manner as in Example 1, but the palladium-containing solution coating (S2-2) and ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  The hydrogen gas sensitive film changes between the transparent state and the colored state in response to the stop and supply of the hydrogen-containing gas, and the transmittance of the laser light changes in the range of 84 to 58%. It was confirmed to have sensitivity. As the response speed, when the hydrogen-containing gas is supplied, it gradually changes to a colored state over 60 seconds as in Example 1. However, when air is introduced, the response speed is slower than in Example 1, It was confirmed that it slowly returned to the original transparent state over 30 to 60 seconds. In addition, the response width did not greatly decrease even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed.

Example 3
Application of the tungsten-containing solution prepared in the same manner as in Example 1 (S1-2) and drying (S1-3) were repeated 10 times to form a base layer having a thickness of about 800 nm, and application of the palladium-containing solution (S2- 2) and ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  In response to the stop and supply of the hydrogen-containing gas, the hydrogen gas sensitive film changes between the transparent state and the colored state, and the transmittance of the laser light greatly changes in the range of 68 to 14%. It was confirmed that the response width was larger than 2. As for the response speed, when the hydrogen-containing gas was supplied, it changed to a colored state over 60 seconds, but it was found that the response was faster in the first 10 seconds than in the case of Examples 1 and 2. Moreover, when air was introduced, it was confirmed that the original transparent state was restored in about 10 seconds. Furthermore, the response width was not significantly reduced even when the supply and stop of the hydrogen-containing gas were repeated 1500 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed.

Example 4
A base layer having a thickness of about 400 nm was formed in the same manner as in Example 1. However, in the preparation of the platinum group metal-containing solution (S2-1), bis (acetylacetonato) platinum (II) (Wako Pure Chemical Industries, Ltd.) Manufactured for organic synthesis) to obtain a platinum-containing solution as a platinum group metal-containing solution. The concentration of the platinum-containing solution was 0.01 mol / L. The solution was stirred for 10 minutes until dissolved at room temperature, and then stirred overnight at room temperature. Further, the application of the platinum-containing solution (S2-2) and the ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  The hydrogen gas sensitive film changes between the transparent state and the colored state in response to the stop and supply of the hydrogen-containing gas, and the transmittance of the laser beam changes greatly in the range of 80 to 29%. It was confirmed that it has sensitivity. As for the response speed, unlike the case where palladium is used for the catalyst layers 3 of Examples 1 to 3, when the hydrogen-containing gas is supplied, it becomes completely colored in about 5 seconds, and the hydrogen-containing gas is supplied as it is. Even if it continued, the transmittance | permeability did not change. In addition, even when air was introduced, it was confirmed that it quickly returned to the original transparent state in about 5 seconds, and it was confirmed that it had a high response speed to hydrogen gas. Furthermore, the response width did not decrease significantly even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed.

Example 5
Application (S1-2) and drying (S1-3) of a tungsten-containing solution prepared in the same manner as in Example 1 were repeated 10 times to form a base layer having a thickness of about 800 nm, and prepared in the same manner as in Example 4. The platinum-containing solution coating (S2-2) and ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  The hydrogen gas sensitive film changes between the transparent state and the colored state in response to the stop and supply of the hydrogen-containing gas, and the transmittance of the laser beam changes greatly in the range of 80 to 9%. Thus, it was confirmed that the response width was larger than that of Example 4. As for the response speed, as in Example 4, when the hydrogen-containing gas was supplied, it was completely colored in about 5 seconds, and even if the hydrogen-containing gas was continuously supplied, the transmittance was not changed. In addition, even when air was introduced, it was confirmed that it quickly returned to the original transparent state in about 5 seconds, and it was confirmed that it had a high response speed to hydrogen gas. Furthermore, the response width did not decrease significantly even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed.

Example 6
In the same manner as in Example 1, a base layer having a thickness of about 400 nm was formed. In the preparation of the platinum group metal-containing solution (S2-1), bis (acetylacetonato) platinum (II) was used to give a concentration of 0. A 02 mol / L platinum-containing solution was obtained. The platinum-containing solution was stirred for 1 hour at room temperature, then heated for 10 minutes until dissolved at 60 ° C., and finally stirred overnight at room temperature. Further, the application of the platinum-containing solution (S2-2) and the ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  Corresponding to the stop and supply of the hydrogen-containing gas, the hydrogen gas-sensitive film changes between the transparent state and the colored state, and the transmittance of the laser light changes greatly in the range of 79 to 23%. It was confirmed that the response width was larger than that of Example 4. As for the response speed, as in Examples 4 and 5, it was confirmed that it quickly responded to hydrogen gas and became completely colored or transparent in about 5 seconds. Furthermore, the response width did not decrease significantly even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed.

Example 7
Application (S1-2) and drying (S1-3) of a tungsten-containing solution prepared in the same manner as in Example 1 were repeated 10 times to form a base layer having a thickness of about 800 nm, and prepared in the same manner as in Example 6. Application of the platinum-containing solution having a concentration of 0.02 mol / L (S2-2) and ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  Corresponding to the stop and supply of the hydrogen-containing gas, the hydrogen gas-sensitive film changes between the transparent state and the colored state, and the transmittance of the laser light changes greatly in the range of 70 to 8%. It was confirmed to have a large response width. As for the response speed, as in Examples 4 to 6, it was confirmed that it quickly responded to hydrogen gas and became completely colored or transparent in about 5 seconds. Furthermore, the response width did not decrease significantly even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed.

Example 8
In the preparation of the tungsten-containing solution (S1-1), the lower alcohol to be added as a solvent is only ultra-dehydrated i-propyl alcohol, and a base layer having a thickness of about 400 nm is formed in the same manner as in Example 1. Application of the prepared palladium-containing solution (S2-2) and ultraviolet treatment (S3) were carried out once to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  Corresponding to the stop and supply of the hydrogen-containing gas, the hydrogen gas sensitive film changed between the transparent state and the colored state, and the response width was not so large, but it was confirmed to be sensitive to hydrogen gas. . Although the sensitivity and durability against hydrogen gas are inferior to those of Example 1 having the same film thickness, it has durability about 100 times with repeated supply and stop of the hydrogen-containing gas. It can be used as a sensor or hydrogen visualization sheet. Further, since one kind of solvent is used alone for the preparation of the tungsten-containing solution (S1-1), there is an advantage that the synthesis operation becomes simpler.

Example 9
In the preparation of the tungsten-containing solution (S1-1), the lower alcohol added as the solvent was only ultra-dehydrated ethanol, a base layer having a thickness of about 400 nm was formed in the same manner as in Example 1, and the palladium prepared in the same manner as in Example 1 Application of the containing solution (S2-2) and ultraviolet treatment (S3) were performed once to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  Corresponding to the stop and supply of the hydrogen-containing gas, the hydrogen gas sensitive film changed between the transparent state and the colored state, and the response width was not so large, but it was confirmed to be sensitive to hydrogen gas. . Similar to Example 8, the sensitivity and durability against hydrogen gas are inferior to those of Example 1 having the same film thickness, but durability of about 150 times with respect to repeated supply and stop of the hydrogen-containing gas. It can be used as a hydrogen sensor or hydrogen visualization sheet. Further, since one kind of solvent is used alone for the preparation of the tungsten-containing solution (S1-1), there is an advantage that the synthesis operation becomes simpler.

Example 10
In the preparation of the tungsten-containing solution (S1-1), the lower alcohol added as a solvent is changed to ultra-dehydrated methanol (manufactured by Wako Pure Chemical Industries, Ltd., for organic synthesis) to form a base layer having a thickness of about 400 nm as in Example 1. Then, a palladium-containing solution prepared in the same manner as in Example 1 (S2-2) and ultraviolet treatment (S3) were performed once to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  Corresponding to the stop and supply of the hydrogen-containing gas, the hydrogen gas sensitive film changed between the transparent state and the colored state, and it was confirmed that the hydrogen gas was sensitive to hydrogen gas. Although the response width and durability against hydrogen gas are inferior to those of Example 1 having the same film thickness, the response width is large and durability is higher than those of Examples 8 and 9, and as a hydrogen sensor or a hydrogen visualization sheet. Can be used. Further, since one kind of solvent is used alone for the preparation of the tungsten-containing solution (S1-1), there is an advantage that the synthesis operation becomes simpler.

Example 11
A base layer having a thickness of about 400 nm was formed in the same manner as in Example 1. In the preparation of the platinum group metal-containing solution (S2-1), palladium chloride (PdCl ₂ , manufactured by Wako Pure Chemical Industries, Ltd., for organic synthesis) ) And a 1% strength hydrochloric acid ethanol solution to obtain a palladium-containing solution different from that of Example 1 as a platinum group metal-containing solution. The concentration of this palladium-containing solution was 0.01 mol / L, and the mixture was stirred at room temperature for 1 hour, then heated at 60 ° C. for 1 hour and then stirred at room temperature overnight. Further, the application of the palladium-containing solution (S2-2) and the ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  Although the hydrogen gas sensitive film was changed between the transparent state and the colored state in response to the stop and supply of the hydrogen-containing gas, it was confirmed that the laser light transmittance changed in the range of 81 to 43%. The response width gradually decreased from the time when the number of repetitions of supplying and stopping the hydrogen-containing gas exceeded 300 times. However, compared with Example 2 in which the same palladium having the same film thickness is used as a catalyst, there are advantages in that the response width in the initial stage is large and the cost of palladium chloride as a raw material for the catalyst layer is low.

Example 12
A base layer having a thickness of about 400 nm was formed in the same manner as in Example 1, but in the preparation of the platinum group metal-containing solution (S2-1), chloroplatinic acid (H ₂ PtCl ₆ .6H ₂ O, Wako Pure Chemical Industries, Ltd.) A platinum-containing solution different from Example 4 was obtained as a platinum group metal-containing solution using Kogyo Co., Ltd. (special grade) and ethanol. The concentration of this platinum-containing solution was 0.01 mol / L, which was obtained by stirring at room temperature to dissolve, and stirring at room temperature overnight. In addition, application of the platinum-containing solution (S2-2) and ultraviolet treatment (S3) were repeated 5 times to obtain a hydrogen gas sensitive film. The measurement result of the transmittance of the laser beam with respect to this hydrogen gas sensitive film is shown in FIG.

  It was confirmed that the hydrogen gas sensitive film changed between the transparent state and the colored state in response to the stop and supply of the hydrogen-containing gas, and the laser light transmittance changed in the range of 74 to 47%. In addition, the response width did not greatly decrease even when the supply and stop of the hydrogen-containing gas were repeated 2000 times or more. That is, good durability of the hydrogen gas sensitive film was confirmed. Compared with Example 4 using the same platinum having the same film thickness as a catalyst, the response width is inferior, but sensitivity equivalent to or higher than that of Example 2 using palladium as a catalyst is expressed and more effective. . Further, since chloroplatinic acid as a raw material is cheaper than bis (acetylacetonato) platinum (II), it is effective in terms of cost.

  As shown in Examples 1 to 12, it was confirmed that the hydrogen gas sensitive film 1 obtained by the above-described manufacturing method has good hydrogen gas sensitivity. In particular, it was found that using platinum as the catalyst of the catalyst layer 3 gave higher response speed, and increasing the film thickness of the light control layer 2 gave a larger response width. Moreover, in the durability, a high tendency was observed when the amount of the platinum group metal was increased. Among them, Example 5 in which a platinum catalyst was supported by repeating application of a platinum-containing solution having a concentration of 0.01 mol / L and ultraviolet treatment five times on a base layer having a thickness of about 800 nm was a higher response speed and a larger response. It was a hydrogen gas sensitive film having a width and high durability, that is, better hydrogen gas sensitivity.

  Next, details of a method for manufacturing a film corresponding to a hydrogen gas sensitive film obtained by changing a part of the above-described manufacturing method as a comparative example and measurement results of laser light transmittance will be described.

[Comparative Example 1]
In preparation of the tungsten-containing solution (S1-1), an attempt was made to prepare a tungsten-containing solution by the same method as in Example 1, using ethylene glycol monomethyl ether instead of lower alcohol as a solvent. However, despite the stirring for one month, the solution remained dark brown and a colorless and transparent solution could not be obtained. This solution was applied onto a substrate and dried by the same method as in Example 1. However, since a transparent film was not obtained, no further production was performed and the transmittance was not measured.

[Comparative Example 2]
A base layer having a thickness of about 400 nm was formed in the same manner as in Example 1, and a palladium-containing solution prepared in the same manner as in Example 1 was applied. However, ultraviolet irradiation was not performed, and 4% by volume of hydrogen as a reducing gas was used. For 15 minutes. Similarly to Example 1, the transmittance of the laser beam with respect to the film thus obtained was measured. The measurement results are shown in FIG.

  It was confirmed that there was no change in light transmittance corresponding to the supply and stop of the hydrogen-containing gas. This is probably because the palladium compound was not reduced to metallic palladium.

[Comparative Example 3]
A base layer having a thickness of about 400 nm was formed in the same manner as in Example 1 and a palladium-containing solution prepared in the same manner as in Example 1 was applied, but irradiation with ultraviolet rays for 15 minutes was performed in the atmosphere. Similarly to Example 1, the transmittance of the laser beam with respect to the film thus obtained was measured. The measurement results are shown in FIG.

  Although a slight change was observed in the transmittance of the laser beam in response to the supply and stop of the hydrogen-containing gas, no change in the observed color was observed. This is thought to be due to insufficient reduction of the palladium compound to metallic palladium.

[Comparative Example 4]
A film of tungsten trioxide (WO ₃ ) was obtained on the substrate by a sputtering method, and was applied using a platinum-containing solution having a concentration of 0.02 mol / L prepared in the same manner as in Example 6 (S2-2) and ultraviolet treatment ( S3) was repeated 5 times to obtain a film. In the same manner as in Example 1, the transmittance of the laser beam to this film was measured. The measurement results are shown in FIG.

  It was confirmed that there was no change in light transmittance corresponding to the supply and stop of the hydrogen-containing gas. Since the tungsten trioxide film does not contain halide ions before the ultraviolet treatment, it is considered that the platinum compound was not reduced to metallic platinum by the ultraviolet treatment.

[Comparative Example 5]
A tungsten-containing solution prepared by the same method as in Example 1 was added to chloroplatinic acid measured in a sample bottle, and the tungsten-platinum-containing solution with a chloroplatinic acid concentration of 0.01 mol / L was stirred at room temperature. I got it. This solution was applied onto a substrate and subjected to the same ultraviolet treatment as in Example 1. Such coating and ultraviolet treatment were repeated 5 times to obtain a colorless and transparent mixed film containing tungsten and platinum. In the same manner as in Example 1, the transmittance of the laser beam to this film was measured. The measurement results are shown in FIG.

  It was confirmed that there was almost no change in light transmittance corresponding to the supply and stop of the hydrogen-containing gas. This is presumably because, in the ultraviolet treatment, hydrogen necessary for the reduction reaction did not reach the tungsten / platinum-containing solution and the platinum compound dispersed in the resulting solution, and the platinum compound was not reduced to metal platinum.

  As mentioned above, although the Example by this invention and the modification based on this were demonstrated, this invention is not necessarily limited to this, A person skilled in the art will deviate from the main point of this invention, or the attached claim. Various alternative embodiments and modifications could be found without doing so.

1 Hydrogen gas sensitive film 2 Light control layer 3 Catalyst layer 4 Substrate

Claims (10)

  A hydrogen gas sensitive film in which a catalyst layer is provided on a light control layer made of tungsten oxide, and the light control layer has irregular communication holes to the boundary of the catalyst layer due to desorption of internal products. A hydrogen gas sensitive membrane characterized by the above. A method for producing a hydrogen gas sensitive film in which a catalyst layer is provided on a light control layer made of tungsten oxide,
A base layer forming step in which a solution prepared by mixing tungsten halide and an alcohol having 1 to 4 carbon atoms is applied on a substrate and dried;
A protective layer forming step of applying a solution prepared by mixing a platinum group metal compound and an organic solvent thereon,
A process for producing a hydrogen gas sensitive film, comprising: an ultraviolet treatment step of irradiating ultraviolet rays in a reducing gas atmosphere to convert the tungsten halide into tungsten oxide and the platinum group metal compound into a platinum group metal. .   3. The hydrogen according to claim 2, wherein in the ultraviolet treatment step, the light control layer is provided with irregular communication holes to the catalyst layer boundary by desorption of the organic substance and halide derived from the alcohol and the tungsten halide. Method for producing a gas sensitive membrane. The tungsten halide is tungsten hexachloride, and the platinum group metal compound is hexachloroplatinic acid, bis (acetylacetonato) platinum (Pt (acac) ₂ ), palladium dichloride, bis (acetylacetonato) palladium ( The method for producing a hydrogen gas-sensitive film according to claim 3, comprising any one of Pd (acac) ₂ ).   5. The method for producing a hydrogen gas sensitive membrane according to claim 2, wherein the alcohol is one or more of methanol, ethanol, n-propyl alcohol, and i-propyl alcohol.   6. The method for producing a hydrogen gas sensitive membrane according to claim 5, wherein the alcohol is a mixture of ethanol and i-propyl alcohol in a volume ratio of 2 to 6 times.   The method for producing a hydrogen gas-sensitive film according to claim 2, wherein the organic solvent is ethylene glycol monomethyl ether and / or ethanol.   8. The hydrogen gas sensitivity according to claim 2, wherein the mixing of the tungsten halide and the alcohol is performed in an inert gas atmosphere having an oxygen concentration of at least 1% by volume or less. A method for producing a membrane.   9. The method for producing a hydrogen gas sensitive film according to claim 2, wherein the base layer forming step forms a film in an amorphous phase. 10. The method for producing a hydrogen gas sensitive film according to claim 2, wherein the reducing gas atmosphere is a hydrogen gas atmosphere.

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