JP2009016267A - Proton conductive film and manufacturing method thereof, and fuel cell and chemical sensor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive film and a manufacturing method thereof, for more easily forming a thick proton conductive film, and to provide a fuel cell and chemical sensor using the same proton conductive film. <P>SOLUTION: The proton conductive film 100 has a frame section 110 with a through-hole 113 penetrated from one surface 111 to the opposite surface 112, and a porous section 120 filled in the through-hole 113, the porous section 120 having fine pores 121 penetrated from one surface 111 to the opposite surface 112. The proton conductive film 100 is manufactured by providing a sol filling-up process of filling-up a sol including a structure regulation agent in the through-hole 113 of the frame section 110, a gelatinization process, and a structure regulation agent removal process of forming the fine pores by removing the structure regulation agent from the gel. The fuel cell has the same proton conductive film, and the chemical sensor also has the same proton conductive film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a proton conductive membrane, a method for producing the same, a fuel cell using the same, and a chemical sensor. More specifically, the present invention relates to a proton conductive membrane having a porous part in a through hole of a mold part, a method for producing the same, a fuel cell using the same, and a chemical sensor.

  As a proton conductive membrane having a fine porous structure, a method using a polymer as a template core is known. According to this method, it is known that a proton conductive membrane having pores perpendicular to the membrane surface can be obtained by arranging polymer bodies serving as mold cores perpendicular to the membrane surface (patents). Reference 1).

JP 2006-008505 A

The method described in Patent Document 1 is excellent in that the oriented pores can be easily obtained, but the film thickness depends on the length of the rod-like polymer. For this reason, in order to obtain a thick proton conductive membrane, a structure-directing agent having a long molecular length is required. However, there are few structure directing agents that can maintain the rod shape even if the molecular length is long, and there is a problem that the rod shape is difficult to maintain in the sol. For this reason, the structure and manufacturing method of the proton-conductive film | membrane which are easy to thicken are calculated | required.
The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a proton conductive membrane that can easily form a thick proton conductive membrane, a method for producing the same, a fuel cell using the same, and a chemical sensor.

That is, the present invention is as follows.
(1) a mold part having a plurality of through holes penetrating from one surface to the opposite surface;
A proton conductive membrane comprising: a porous portion filled in each through-hole and penetrating from the one surface to the opposite surface and having a plurality of pores having a smaller diameter than the through-hole.
(2) The proton conductive membrane according to (1), wherein the through holes are aligned and arranged from the one surface toward the opposite surface.
(3) The proton conductive membrane according to (1) or (2), wherein the pores are aligned and arranged from the one surface of the mold part toward the opposite surface.
(4) The proton conductive membrane according to any one of (1) to (3), wherein the porous portion has a silicon oxide skeleton.
(5) The proton conductive membrane according to any one of (1) to (4), wherein the porous portion is subjected to phosphoric acid treatment.
(6) The proton conductive membrane according to any one of (1) to (5), wherein the mold part is anodized aluminum.
(7) The proton conductive membrane according to the above (1), wherein the mold part is cellulose nitride.
(8) The method for producing a proton conductive membrane according to (1) above,
A sol filling step of filling a sol containing a structure-directing agent in the through hole of the mold part;
A gelation step of gelling the sol;
A structure-directing agent removing step of removing the structure-directing agent from the gel to form the pores.
(9) The method for producing a proton conductor according to (8), further including a phosphoric acid treatment step of phosphoric acid treating the porous portion.
(10) A fuel cell comprising the proton conductive membrane according to any one of (1) to (7) above.
(11) A chemical sensor comprising the proton conductive membrane according to any one of (1) to (7) above.

According to the proton conductive membrane of the present invention, it is possible to obtain a proton conductive membrane having pores penetrating front and back with a simple configuration. Moreover, the thickness of the proton conductive membrane can be controlled by the thickness of the mold part, and a thick proton conductive membrane can be formed. Furthermore, the strength of the proton conductive membrane can be secured to the mold part, and the strength of the proton conductive membrane can be ensured without the need for another support member.
When the through holes are aligned and arranged, the number of through holes per unit area can be increased, and higher proton conductivity can be obtained.
When the pores are aligned and arranged, the number of pores per unit area can be increased, and particularly high proton conductivity can be obtained.
When the porous portion has a silicon oxide skeleton, a proton conductive membrane excellent in heat resistance and durability can be obtained, and further, the proton conductivity can be easily improved by phosphoric acid treatment or the like.
When the porous portion is subjected to phosphoric acid treatment, it is possible to obtain more excellent proton conductivity as compared with the case where the porous portion is not subjected to phosphoric acid treatment.
When the formwork is anodized aluminum, the through-holes can be easily oriented and arranged from one surface to the opposite surface, and the pores can be oriented and arranged in the same way, with excellent proton conductivity. Sex can be obtained. Furthermore, when the mold part is made of alumina, a proton conductive membrane having particularly excellent durability can be obtained.
When the mold part is made of cellulose nitride, the three-dimensionally arranged pores can be obtained by using the three-dimensional through-holes.

According to the method for producing a proton conductive membrane of the present invention, the structure-directing agent can be forcibly oriented in the through-hole, and protons having pores penetrating the front and back without depending on the molecular length of the structure-directing agent used. A conductive film can be obtained. Moreover, the thickness of the proton conductive membrane can be controlled by the thickness of the mold part, and a thick proton conductive membrane can be formed. Furthermore, the strength of the entire proton conductive membrane can be secured to the mold part itself, and the mechanical strength can be improved.
When a phosphoric acid treatment step for phosphoric acid-treating the porous portion is provided, more excellent proton conductivity can be obtained as compared with a case where the porous portion is not phosphoric acid-treated.
According to the fuel cell of the present invention, a fuel cell having the same effects as the proton conductive membrane of the present invention can be obtained.
According to the chemical sensor of the present invention, the chemical sensor having the effect of the proton conductive membrane of the present invention as it is can be obtained.

The present invention will be described in detail below.
[1] Proton conductive membrane The proton conductive membrane of the present invention (100 in FIG. 1)
A mold part (110) having a plurality of through holes (113) penetrating from one surface (111) to the opposite surface (112);
A porous portion (120) filled in each through hole (113), penetrating from one surface (111) to the opposite surface (112) and having a plurality of pores (121) having a smaller diameter than the through hole (113); It is characterized by having.

  The “formwork part (110)” is a base body that becomes a formwork of the porous part, and is usually a plate shape or a film shape. As this mold part, any material can be used without particular limitation as long as it is a material having a through-hole or capable of forming a through-hole. In particular, a substrate on which a through hole is provided in advance is preferable. For example, various filters can be mentioned. The material which comprises a mold part is not specifically limited, Various inorganic materials and / or organic materials can be used. Examples of the inorganic material include ceramics, glass, and metal. Among these, an insulating material is preferable and ceramic is more preferable.

Although the component which comprises the said ceramic is not specifically limited, For example, an alumina, titania, a silica, magnesia etc. are mentioned. These may use only 1 type and may use 2 or more types together. Of these, alumina is particularly preferable, and anodized aluminum is more preferable. Anodized aluminum is obtained by anodizing aluminum in an acidic electrolytic solution, and has pores (through-holes) aligned and arranged on an aluminum oxide film formed on the surface of a substrate.
On the other hand, examples of the organic material include cellulose nitride, polytetrafluoroethylene, polyethylene (such as cold stretch pore formation), and polypropylene (such as cold stretch pore formation). These may use only 1 type and may use 2 or more types together. Of these, cellulose nitride can be used. When nitrided cellulose is used, three-dimensionally entangled through holes can be obtained.

  The “through hole (113)” is a hole penetrating from one surface (111) to the opposite surface (112) of the mold part (110). The through hole may be a columnar hole or a communication hole (that is, a bent hole). Of these, columnar holes are preferred. By being a columnar hole, the proton conduction path can be made shorter. Furthermore, the through holes may not be oriented, but are preferably oriented and arranged from one surface of the mold part to the opposite surface. More through holes can be obtained with a smaller area.

  Although the thickness of a mold part is not specifically limited, 0.5-200 micrometers is preferable. If it is this range, the merit (said effect) using a mold part will be obtained, and especially when using the production method of the present invention described later, a sol filling step (a sol containing a structure-directing agent in a through-hole is used). The step of filling) can be performed more smoothly. The thickness of the mold part is more preferably 20 to 100 μm, and particularly preferably 60 to 80 μm.

The opening shape (cross-sectional shape) of the through hole is not particularly limited, and may be circular, rectangular, or other shapes.
The average diameter of the through holes (average maximum length when the opening shape is non-circular) is not particularly limited, but is preferably 0.15 to 2.0 μm. If it is this range, when using the manufacturing method of this invention mentioned later, it is easy to be filled with sol in a sol filling process, and it is easy to hold | maintain sol in a through-hole. Furthermore, it is preferable that a through-hole has an average aperture of 10 to 400 times with respect to a pore described later.
Further, the density of the through holes is not particularly limited, but 80,000 to 30,000,000 per 1 mm ² of the surface of the mold part (one surface on which the through holes are opened or the opposite surface) (more preferably 1,200,000 to 25,000,000, more preferably 1,200,000 to 16,000,000).

  In addition, the length of the through hole is not particularly limited, but in the case of a columnar hole, it is 1 to 2 times the thickness of the mold part (that is, 0 to 30 with respect to the film thickness direction of the mold part). (Angle range of degrees) is preferable, 1 to 1.5 times is more preferable, and 1 to 1.2 times is particularly preferable. That is, it is preferable that the through hole is formed in a state that is almost parallel to the film thickness direction of the mold part. By having such a through-hole, it is easy to fill the sol described later, and the path of the obtained pore can be shortened.

  The “porous part (120)” is a part in the through hole (113) and has a pore (121) penetrating from one surface (111) to the opposite surface (112) of the mold part (110). The average diameter of the pores (121) (average maximum length when the opening shape is non-circular) is not particularly limited, but is usually 1 to 20 nm (further 1 to 15 nm, particularly 1 to 10 nm). The average diameter of the pores can be controlled by the shape of the structure directing agent used during production. The opening shape (cross-sectional shape) of the pores is not particularly limited, and may be circular, rectangular, or other shapes.

Further, the pore may be a columnar hole or a communication hole (that is, a bent hole). Of these, columnar holes are preferred. By being a columnar hole, the proton conduction path can be made shorter. However, the columnar hole means a substantially columnar shape, and for example, the shape in the hole includes a spiral shape or a bellows shape.
Further, the pores may not be oriented, but are preferably oriented and arranged from one surface of the mold part to the opposite surface. More pores can be obtained with a smaller area. The arrangement form when the pores are oriented and arranged is not particularly limited, but is preferably arranged in a hexagonal structure. In the case of a hexagonal structure, a peak of at least the (n00) plane among the (n00) plane and the (n10) plane is recognized in the chart by X-ray diffraction measurement of the proton conductive membrane (where n is 1 to 5). Further, the distance between the pores is not particularly limited, but the distance between the centers of the pores can be, for example, 50 nm or less (further 40 nm or less, particularly 30 nm or less, usually 3 nm or more).

  The length of the pore is not particularly limited, but in the case of a columnar hole, it is 1 to 2 times the average thickness of the mold part (that is, an angle of 0 to 30 degrees with respect to the thickness direction of the mold part). Range) is preferable, 1 to 1.5 times is more preferable, and 1 to 1.2 times is particularly preferable. That is, it is preferable that the pores are arranged more parallel to the thickness direction of the mold part. Proton conduction paths can be shortened by having such pores.

The porous portion may be formed of any material, may be an inorganic material, or may be an organic material. However, an inorganic material suitable for the sol-gel method is preferable as described later, and particularly an inorganic oxidation material. Things are preferred. Examples of the inorganic oxide include oxides containing elements such as Si, Zr, Ti, Al, P, W, and B (SiO ₂ , ZrO ₂ , TiO ₂ , Al ₂ O ₃ , P ₂ O ₅ , WO ₅ and B ₂ O ₅ etc.). These elements may be contained alone or in combination of two or more. Among these, sufficient strength as a structure can be exhibited, and since it has excellent chemical stability and thermal stability, Si (silica etc.), Zr (zirconia etc.), Ti (titania etc.) and Al (alumina etc.) Of these, an oxide containing at least one element as a main component is preferable. Further, among these, SiO ₂ is particularly preferable because gel formation by the sol-gel method is easy. When SiO ₂ is the main component (that is, a silicon oxide skeleton), the content of SiO ₂ is not particularly limited, but when the entire porous portion is 100 mass%, SiO ₂ is 50 mass% or more ( More preferably, it may be 80 mass% or more and 100 mass%).

The porous part may be subjected to a proton conductivity improving treatment for further improving proton conductivity. Examples of the proton conductivity improving treatment include phosphoric acid treatment and sulfonic acid treatment. Of these, phosphoric acid treatment is preferred. The phosphoric acid content by the phosphoric acid treatment is not particularly limited, but is 30% by mass or less (more preferably 40% by mass or less, usually 2% by mass or more) in terms of P ₂ O ₅ when the entire porous portion is 100% by mass. ) Is preferable.
Further, as another proton conductivity improving treatment, a manganese oxide crystal introduction treatment can be mentioned. The manganese oxide crystal introduction treatment is a treatment for depositing manganese oxide on the surface (particularly in the pores) of the material constituting the porous portion. The manganese oxide crystal introduction treatment may be performed alone, but is preferably performed in addition to the phosphoric acid treatment. Thereby, particularly excellent proton conductivity can be obtained.

  The proton conductive membrane of the present invention usually comprises an electrode in addition to the mold part and the porous part. The electrode can be formed from, for example, a conductive metal and a solid electrolyte. One side of the proton conductive membrane of the present invention (the electrode may be provided in direct contact with one side, or may be provided through another material) and the other side (the electrode in direct contact with the opposite side) Or may be provided via other materials).

[2] Method for Producing Proton Conducting Membrane The method for producing a proton conducting membrane of the present invention includes a sol filling step, a gelation step, and a structure directing agent removing step.

The “sol filling step” is a step of filling a sol containing a structure-directing agent in the through holes of the mold part.
The “sol” contains a structure-directing agent. The “structure-directing agent” serves as a mold core that forms pores and / or forms a mold core that forms pores. A mold core forms an inner shape with respect to a mold (corresponding to a through hole in a mold frame) that forms an outer shape. That is, the space formed by removing the mold core is a pore. This structure directing agent may be made of an inorganic material, but is usually made of an organic polymer. This is because the organic polymer makes it easy to remove by baking and solvent extraction as described later.

In addition, when a structure directing agent composed of an organic polymer is used, the obtained template core may be formed from a single molecule of an organic polymer, so that a plurality of organic polymers are collected to form a single template core. A mold core may be formed. A micelle is mentioned as one in which a plurality of organic polymers gather to form one template core.
Although the kind of structure-directing agent is not particularly limited, various surfactants can be mentioned. In particular, for the purpose of forming columnar pores aligned in a hexagonal structure, Pluronic P123, CTAB (cetyltrimethylammonium bromide), C ₁₆ EO ₁₀ {C ₁₆ H ₃₃ (OCH ₂ CH ₂ ) ₁₀ OH}, Pluronic P103, Pluronic P85, Pluronic P65 and the like are preferable. These may use only 1 type and may use 2 or more types together.

In addition to the structure directing agent, the sol usually contains a structural material source, a sol-gel catalyst, and water.
The structural material source is a compound containing an element that becomes a structural material (skeleton in the porous portion) constituting the proton conductive membrane, such as various alkoxides (alkoxysilane, zirconium alkoxide, titanium alkoxide, aluminum alkoxide, etc.), Examples include water-soluble salts of various metal elements (sodium silicate, lithium silicate, etc.), colloidal metal oxides (colloidal silica, etc.), and the like. Among these, various alkoxides are preferable, and it is particularly preferable to use alkoxysilane as a main component. Examples of the alkoxysilane include tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, and bis (triethoxysilyl) ethane. These may use only 1 type and may use 2 or more types together. Moreover, when a phosphorus element is contained, it is preferable to use an alkoxide made of P (O) (OC _n H _{2n + 1} ) ₃ or the like. Among these, compounds having n of 3 to 5 are preferable.

As the sol-gel catalyst, acids, bases, amine compounds and the like can be used. Of these, acids and bases are preferred. Examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, and aqueous solutions thereof. These may use only 1 type and may use 2 or more types together. Examples of the base include alkali metal hydroxides, alkaline earth metal hydroxides, and aqueous solutions thereof. These may use only 1 type and may use 2 or more types together.
The sol can contain other components in addition to the structural material source, the sol-gel catalyst, and water. Examples of other components include a sol viscosity adjusting component (alcohol and the like), a dispersant (surfactant and the like), a sol-gel reaction promoting component, and the like. These may use only 1 type and may use 2 or more types together.

  The method for filling the mold part with the sol is not particularly limited, and various methods can be used. That is, for example, the mold part may be disposed in the sol, and the sol may be immersed and filled in the through hole of the mold part, or may be filled by application and penetration. Further, when filling, it may be pressurized or inhaled. These methods may use only 1 type and may use 2 or more types together. Among these, the method of immersion and penetration is preferable. This is because filling can be reliably performed while suppressing a burden on the mold part.

  The “gelation step” is a step of gelling the sol filled in the through hole. The method for gelation is not particularly limited. In the case of the sol-gel method using various alkoxides as the main component of the sol, the hydrolysis proceeds by the action of the sol-gel catalyst and the gel is gradually formed. Moreover, it can be gelatinized by removing the contained water (including part or all of the removal). In the gelation, it is not necessary to perform heating, but it is preferable to perform heating. Gelation can be promoted by heating. In the case of heating, for example, heating at 40 to 100 ° C. (preferably 45 to 80 ° C., particularly preferably 50 to 70 ° C.) for 1 to 48 hours (preferably 3 to 24 hours, particularly preferably 5 to 15 hours). It is preferable to carry out. Moreover, when performing this heating, you may heat by an open system, However, It is preferable to heat by a closed system.

  The “structure-directing agent removal step” is a step of forming pores by removing the structure-directing agent (template core) from the gel obtained in the gelation step. The above removal means removal of a part or all of the structure directing agent. This removal method is not particularly limited. That is, for example, when the structure directing agent is made of an organic polymer, it can be removed by burning. Moreover, it can be removed by solvent extraction or dissolving the structure-directing agent regardless of the type of structure-directing agent. These methods may use only 1 type and may use 2 or more types together. Among these, a method of using an organic polymer as a structure directing agent and removing it by baking is preferable. As a result, the structure-directing agent can be removed more reliably, and the strength of the gel (porous portion) can be improved.

When firing, the firing conditions are not particularly limited. The reaction may be performed in the air, in an inert atmosphere, in a reducing atmosphere, or a combination thereof. Furthermore, the firing may be performed only once, or may be performed in several times by dividing the process. When performing by dividing a process, you may carry out continuously and may carry out intermittently.
The firing temperature is not particularly limited, but the maximum temperature is usually 300 ° C. or higher (preferably 300 to 600 ° C., more preferably 350 to 450 ° C., usually 700 ° C. or lower). In this range, it is possible to suppress the pores from being blocked while burning the structure-directing agent more reliably. Furthermore, the firing time can be 1 to 48 hours (preferably 3 to 24 hours, particularly preferably 5 to 15 hours). Moreover, although the temperature increase rate is not specifically limited, For example, a temperature increase rate of 50 ° C./min or less (more preferably 5 ° C./min or less, usually 0.1 ° C./min or more) is preferable. By setting the heating rate within this range, it is possible to reduce or eliminate the residual carbon in the proton conductive membrane obtained.

In the manufacturing method of this invention, other processes can be provided in addition to the sol filling process, the gelling process, and the structure directing agent removing process. Examples of other steps include a proton conductivity improving treatment step for improving proton conductivity. Examples of the proton conductivity improving treatment include a phosphoric acid treatment step and a sulfonic acid treatment step. Among these, it is preferable to provide a phosphoric acid treatment step. The phosphoric acid treatment step is a step of adding a phosphate group to the surface (particularly in the pores) of the material constituting the porous portion. This phosphoric acid treatment may be carried out in any way. For example, the surface of the porous part is modified by bringing the porous part into contact with a mixed solution of an organic solvent and phosphorus oxychloride (POCl ₃ ). Acid treatment can be performed. In addition, although phosphorylation can be further performed by hydrolyzing the P—Cl bond remaining on the surface of the porous portion, it is preferably performed at a low temperature of 160 ° C. or less. If the hydrolysis is performed at an excessively high temperature, the silicon oxide skeleton may also be hydrolyzed to lower the proton conductivity.

  In addition to the phosphoric acid treatment step and the sulfonic acid treatment step, the proton conductivity improving treatment includes a manganese oxide crystal introduction treatment step. The manganese oxide crystal introduction treatment step may be carried out in any way. For example, the porous portion and a solution containing manganese ions (such as an aqueous solution) are brought into contact (particularly preferably immersed) and then dried. Can be done. The drying at this time may be performed at room temperature, but is preferably performed by heating. When heating, it is preferable to carry out at 100 degrees C or less (More preferably 90 degrees C or less, More preferably 80 degrees C or less, Usually 40 degrees C or less). Moreover, although drying may be performed in any atmosphere, it is preferably performed in a vacuum.

[3] Fuel Cell The fuel cell (500) of the present invention is characterized by using the proton conductive membrane of the present invention. The configuration of the fuel cell is not particularly limited, but usually includes a proton conductive membrane (511, 521) and a pair of electrodes (512, 513, 522, and 523) sandwiching the proton conductive membrane. This electrode can be formed of, for example, a conductive material and a solid electrolyte (see FIG. 12).

Further, when the unit cell (510, 520) includes the proton conductive membrane and a pair of electrodes sandwiching the proton conductive membrane, only one unit cell (510, 520) may be used. Two or more may be used in combination. When two or more are used in combination, each unit cell is preferably used by being laminated. In this case, it is preferable to sandwich a separator (530) between the unit cells.
The types of fuel gas and combustion-supporting gas used in this fuel cell are not particularly limited. Examples of the fuel gas include hydrogen and methanol, and examples of the fuel-supporting gas include air and oxygen. Only 1 type may be used for fuel gas and it may use 2 or more types together. Moreover, only 1 type may be used for a combustion-supporting gas and it may use 2 or more types together.
When the separator (530) is used, the fuel gas and the combustion-supporting gas are supplied to each electrode using the fuel gas channel (541) and the combustion-supporting gas channel (542) provided in the separator (530). Can be supplied to the surface.

[4] Chemical sensor The chemical sensor (600) of the present invention is characterized by using the proton conductive membrane (611) of the present invention. The configuration of the chemical sensor is not particularly limited, but usually includes a proton conductive membrane (611) and a pair of electrodes (612 and 613). This electrode can be formed of, for example, a conductive material and a solid electrolyte.
Examples of components detected by this chemical sensor include hydrogen, methanol, carbon monoxide, and water (humidity).

Furthermore, the chemical sensor of the present invention can include other portions in addition to the proton conductive membrane (611) and the electrodes (612 and 613). More specifically, the chemical sensor can be configured as shown in FIG. That is, a metal container (601) provided with a detection gas introduction hole (607) and a detection gas discharge hole (605), a proton conductive membrane (611) of the present invention, and electrodes (612 and 613) sandwiching the proton conductive membrane (611) are provided. An element part, a lower support (615) made of alumina or the like for supporting the element part, and an upper support (made of alumina or the like for fixing the element part and the lower support (615) to the metal container (601) ( 614), a spacer (602), various O-rings (603), a negative electrode terminal (608), and a positive electrode terminal (609). The lower support (615) is provided with a diffusion-controlling hole (604) for guiding the detection gas to the electrode (612). Furthermore, an electrode (624) electrically connected to the electrode (613) is provided on the lower surface of the lower support (615) in order to electrically connect the electrode (613) to the metal container (601). Is formed. In addition, electrodes (621 and 623) that are electrically connected to each other are formed on the front and back surfaces of the upper support (614). Accordingly, the electrode (612) is electrically connected to the negative terminal (608) through the electrode (623) and the electrode (621). Further, a seal member (605) made of epoxy or the like is provided for the purpose of preventing the detection gas introduced to the electrode (613) side through the diffusion rate controlling hole (604) from leaking to the electrode (612) side. Yes.
The detection gas is introduced to the electrode (613) side through the detection gas diffusion rate controlling hole (604), and decomposes into ions on the electrode (613). The generated ions are pumped to the electrode (612) side through the proton conductive membrane (611) and become gas again on the electrode (612). The gas generated on the electrode (612) is discharged from the gas discharge hole (605) to the outside of the sensor (600) through a flow path provided in the upper support (614). At this time, the concentration of the detection gas (for example, hydrogen gas) is measured by measuring the current generated by the ions (for example, protons) generated on the electrode (613) passing through the proton conductive membrane (611). It can be performed.

Hereinafter, the present invention will be described in detail based on examples.
[1] Preparation of proton conductive membrane (see FIGS. 2 and 3)
(Macroporous-template-supported Mesoporous Membranes)
(1) Preparation of a porous mold (Macroporous-template) Thickness (av.thickness) of 60μm, diameter (av.diameter of template) of 21mm, and many through-holes with an average diameter (av.pore size) of 200nm A disk-shaped anodic aluminum oxide having a porosity of (Porosity) of 25 to 50% was prepared as a porous mold body 110 (to be a mold part in the proton conductive membrane).

(2) Preparation of silica sol (FIG. 2 “P1” “P2”)
Ethanol (C ₂ H ₅ OH), pure water (H ₂ O), hydrochloric acid (HCl), structure directing agent (P123), and silica source (TEOS) are mixed at a molar ratio (at room temperature of 25 ° C.) of C ₂ H _5. Each component was added so that OH: H ₂ O: HCl: P123: TEOS = 1: 0.11: 0.002: 0.002: 0.1 to obtain a sol (FIG. 2 “P1” − Sol preparation step). The structure directing agent 200 includes PEO ₂₀ PPO ₇₀ PEO ₂₀ nonionic surfactant having an ABA type triblock structure (manufactured by BASF, “Pluronic P123”, weight average molecular weight Mw of 5800, PEO is polyethylene oxide , PPO was polypropylene oxide).
The mixture obtained by mixing the above components was stirred to form rod-like micelles 300 formed by the structure-directing agent 200 gathering in the sol 401 (FIG. 2 “P2” —micelle formation step).

(3) Filling silica sol
The porous mold body 110 prepared in (1) above was placed on the filter paper attached to the filtration flask. Next, the sol 401 obtained in (2) above is poured into the filtration flask, and the sol 401 is passed through the through-hole 113 (through-hole) of the porous mold body 110, so that the sol 401 is preliminarily placed in the mold section 110. Infiltrated (familiarized) (FIG. 2 “P3” —sol pre-infiltration step).
Thereafter, the porous mold body 110 is put into a container in which the same sol 401 is put, and left at room temperature (25 ° C.) for 20 hours, so that the sol 401 is placed in the through hole 113 of the porous mold body 110. It was infiltrated (FIG. 3 “P4” —sol immersion infiltration step).

(4) Gelation step and structure-directing agent removal step The porous mold body 110 obtained by the above (3) and filled with the sol 401 in the through-hole 113 is sealed in a sealed container 801 at 60 ° C. for 12 hours. It was held and gelled (FIG. 3 “P5” —gelation step).
Thereafter, the container is further opened (open container 802) and baked at 400 ° C. for 12 hours to burn off and remove the structure directing agent 200 in the gel 402 (FIG. 3 “P6” —structure directing agent removing step), A proton conductive membrane 100 was obtained. Here, in the gelation step and the structure directing agent removal step, heating was performed by the heater 700 disposed in the vicinity of the sealed container 801 and the open container 802.

[2] Evaluation of proton conductive membrane (before phosphoric acid treatment) (1) Preparation of reference sample used for evaluation of proton conductive membrane Silica sol itself used in [1] above without permeating into the porous mold Was obtained by solidifying under the same conditions as [1] (4) above. The shape of the reference sample is 70 to 80 μm in thickness (av. Thickness) and 50 mm in diameter (av. Diameter of template).

(2) Small-angle X-ray diffraction measurement and evaluation Small-angle X-ray diffraction (SAXRD) measurement of both the proton conductive membrane obtained in [1] above and the reference sample obtained in [2] (1) above. Went. The result is shown in FIG. In addition, this small angle X-ray diffraction measurement uses Cu-Kα (λ = 1.5406 mm) in the model “X′Pert-MPD” manufactured by Philips Co., and applied 40 mA at 45 kV to the X-ray tube. Measurements were made at a step width of .002 degrees and a scan speed of 0.2 degrees / minute.

  From FIG. 4, a peak due to the (100) plane was observed at 1.26 degrees in the reference sample. On the other hand, a very weak peak due to the (100) plane was observed at 1.13 degrees in the proton conductive membrane. From this, it can be seen that all have pores having a hexagonal structure. The reference sample consists entirely of gel, whereas the proton conductive membrane has a small proportion of the porous portion corresponding to the reference sample, and the (100) plane peak in the proton conductive membrane is weaker than the reference sample. It is thought that it became. The average interpore distance of the reference sample was 8.09 nm, whereas the average interpore distance of the proton conductive membrane was 9.02 nm. This is presumably because the reference sample does not have a mold at the time of firing, and the firing shrinkage is larger than that of the porous portion.

(3) Evaluation by nitrogen adsorption / desorption isotherm For both the proton conductive membrane obtained in the above [1] and the reference sample obtained in the above [2] (1), a pore distribution measuring apparatus (Quantachrome) Nitrogen adsorption / desorption isotherm was obtained using “Model“ Autosorb-1 ”, used at 77K). The results are shown in FIG. Further, the nitrogen adsorption / desorption isotherm (FIG. 5) was analyzed by the BJH method to obtain a pore distribution curve. The results are shown in FIG.

From FIG. 5, the isotherm by the reference sample belongs to “type IV” defined in IUPAC and shows hysteresis, indicating the presence of pores. On the other hand, the isotherm of the proton conductive membrane also shows hysteresis, indicating the presence of pores. The isotherms of this proton conducting membrane, a region P / _{P 0} is 0.4 to 0.8, and a region P / _{P 0} is 0.8 to 1.0, two features of It is thought that it has two types of mesostructures because it has a typical region.

  Furthermore, it can be seen from FIG. 6 that the reference sample has pores with a narrower opening diameter range and a smaller diameter (about 3.5 to 9.0 nm) compared to the pores of the proton conducting membrane. In particular, a peak is observed at 6.4 nm. On the other hand, it can be seen that pores having a larger opening diameter range and a larger diameter (about 2.0 to 20 nm) are recognized in the proton conductive membrane as compared with the pores of the reference sample. In particular, peaks are observed at 6.7 nm and 9.7 nm. From the relationship between these opening diameters and the result of the previous X-ray diffraction measurement, it is predicted that the reference sample had a larger shrinkage during firing than the proton conductive membrane.

(4) Scanning electron microscope (hereinafter, simply referred to as “SEM”) in which the surface of the porous mold body used in the above [1] (1) is enlarged 11,000 times by SEM and TEM. An image (SEM image) was obtained. This SEM image is shown in FIG. For the SEM, a model “JSM-6301” manufactured by JEOL Ltd. was used.
Further, in the proton conductive membrane obtained up to the above [1] (4) (that is, in the state where the porous portion is filled with the porous portion), the same through hole as in FIG. 7 is opened. An SEM image was obtained with the surface to be magnified 11,000 times. This SEM image is shown in FIG.
Further, the surface of the proton conductive membrane obtained up to the above [1] (4) where the same through hole as in FIG. 7 is opened is enlarged by 43,000 times, and the porous portion filled in the through hole is formed. An observable image was obtained with a transmission electron microscope (hereinafter simply referred to as “TEM”). This TEM image is shown in FIG. For the TEM, JEOL Co., Ltd. type “JEM-2100F” was used at 200 kV.

From FIG. 7, it can be seen that through holes having an opening diameter of about 200 nm are aligned and arranged in the anodized aluminum used in this example.
From FIG. 8, it can be seen that the through hole of the anodized aluminum used in this example is filled with a porous portion made of silica.
From FIG. 9, it is recognized that pores having a diameter (about 6.0 nm) that is much smaller than the opening diameter of the through hole are opened in one through hole (small white dot image in FIG. 9). ). And it turns out that the pore in a through-hole is orientated and arranged toward the opposite surface from one surface of this form part from this opening state.

From the results of [2] (2) to [2] (4), the obtained proton conductive membrane has a large number of through-holes aligned from one surface of the mold part to the opposite surface (per 1 mm ^2). Density of about 11,000,000). Furthermore, a porous portion is provided in the through hole, and pores smaller than the opening diameter of the through hole are aligned and arranged from one surface to the opposite surface (in the through hole). It can be seen that about 0.7 per 50 nm square and about 0.2 per 50 nm square in the entire mold part).

[3] Phosphoric acid treatment of proton conductive membrane (1) Phosphoric acid treatment step A mixed solution containing 5 mL of phosphorus oxychloride (POCl ₃ ) with respect to 100 mL of anhydrous toluene was heated and maintained at 110 ° C. The proton conductive membrane obtained up to the above [1] (4) was immersed in this heated and heat-mixed solution for 4 hours for phosphoric acid treatment. Thereafter, the immersed proton conductive membrane was repeatedly washed in anhydrous toluene, and then dried overnight under vacuum to obtain a phosphoric acid-treated proton conductive membrane.

[4] Evaluation of proton conductive membrane (after phosphoric acid treatment) and introduction of MnO ₂ nanocrystals (1) Confirmation of phosphoric acid treatment Proton conductive membrane obtained by [1] and (4) above (unphosphoric acid treatment) ) And FT-IR measurement was performed on the two specimens of the phosphoric acid-treated proton conductive membrane obtained in the above [3] (1). The result is shown in FIG. For the FT-IR, a model “FT / IR 460” manufactured by JASCO Corporation was used.

From the result of FIG. 10, a peak derived from the stretching vibration of Si—OH is observed at a wavelength of 960 cm ⁻¹ from FIG. It can be seen that this peak is not recognized in FIG. This indicates that the Si—OH group was changed to Si—O—P (= 0) Clx (x = 1, 2) by the phosphoric acid treatment. The —P (= 0) Clx group can be converted to a phosphate group by further hydrolysis under steam. Therefore, it can be said that the phosphoric acid treatment is effective for replacing the Si—OH group with a phosphate group having high proton conductivity.

(2) Introduction of MnO ₂ nanocrystals The proton-treated proton conductive membrane obtained in [3] (1) above was immersed in 100 mL of a KMnO ₄ aqueous solution (concentration 0.1 M) at room temperature for about 6 hours. After being taken out, it was washed well with deionized water, then dried at 70 ° C. and then vacuum dried to obtain a proton conductive membrane having MnO ₂ nanocrystals introduced into the pores.

(3) Evaluation of proton conductivity A gold electrode having a diameter of 3 mm is applied to the surface opposite to the one surface of the proton conductive membrane (unphosphoric acid treatment) obtained up to the above [1] and (4) and coated. A cell was formed by connecting each electrode to a wire made of pure copper. Then, using an impedance analyzer (Solartron, model “SI-1260”), the proton conductivity of the cell is measured using a 50 mV AC amplifier in the frequency range of 10 to 1.0 × 10 ⁷ kHz. did. The final proton conductivity was calculated from the semicircular Nyquist plots, the thickness of the conductive membrane, and the area of the gold electrode.
Similarly, the porous mold body used as the mold part of the proton conductive membrane in [1] above (having no porous part in the through hole) and the above [3] (1) are obtained. The same measurement was performed on two test bodies, namely, a proton-conductive membrane treated with phosphoric acid. The results are shown in FIG.
Further, in the same manner, the same measurement was performed on a specimen of a proton conductive membrane in which MnO ₂ nanocrystals were contained in the pores obtained in the above [4] (2). The results are shown in FIG.

From the result of FIG. 11, the proton conductive membrane (FIG. 11) having the porous portion is compared with the proton conductivity in the test body (“■” in FIG. 11) having only the porous mold body not having the mesoporous body portion. 11, “Δ”, “□”, and “◯”) show that proton conductivity is as high as about 4 orders at each temperature. That is, it can be seen that proton conductivity can be drastically improved by introducing a porous portion into the porous mold body. In addition, the proton conductive membrane treated with phosphoric acid (“□” in FIG. 11) has a proton conductivity in a practical temperature range of 50 ° C. (1000 / T≈3.09) or higher and is not subjected to phosphoric acid treatment. It can be seen that this is improved compared to the proton conductive membrane (“Δ” in FIG. 11). Further, the proton conductive membrane treated with phosphoric acid and introduced with MnO ₂ nanocrystals (“◯” in FIG. 11) is further measured compared with the proton conductive membrane treated with phosphoric acid (“□” in FIG. 11). It can be seen that proton conductivity is improved over the entire temperature range.

  In addition, in this invention, it can restrict to what is shown to said specific Example, It can be set as the Example variously changed within the range of this invention according to the objective and the use.

  The proton conductive membrane and the production method thereof of the present invention are widely used in the field of proton conductivity application. This proton conductive membrane is used as various electrolyte membranes, catalyst carriers, and separation membranes. For example, automobile-related fields (fuel cells, various chemical sensors, fuel gas purification and exhaust gas purification), synthetic chemistry-related fields (various chemical sensors, catalyst carriers, component separation and purification, etc.), petroleum-related fields (various chemical sensors, component purification) , Component separation and catalyst carrier, etc.), household appliances related fields (fuel cells, various chemical sensors, adsorption, drying, deodorization, antibacterials, etc.), environment related fields (various chemical sensors, adsorption, drying, deodorization, antibacterials, etc.) and medical care It can be widely used in related fields.

It is explanatory drawing which shows typically the cross section of an example of the proton-conductive film | membrane of this invention. It is explanatory drawing which illustrates some processes in the manufacturing method of this invention. FIG. 3 is an explanatory diagram illustrating a process continued from FIG. 2. 2 is an X-ray diffraction chart of each of the proton conductive membrane of the present invention and the gel specimen used in the examples. It is a nitrogen adsorption / desorption isotherm of the proton conducting membrane and the gel specimen according to the example. It is a pore distribution curve of the proton-conductive film | membrane and gel test body concerning an Example. It is a SEM image of the through-hole of the mold part concerning an Example. It is a SEM image of the surface of the proton-conductive film | membrane with which the porous part was filled in the through-hole concerning an Example. It is a TEM image which expands and shows the porous part in the through-hole concerning an Example. It is a chart of the reflection absorption spectrum of FT-IR concerning an Example. It is a graph which shows the proton conductivity in the measurement temperature of each proton conductive film concerning an Example. It is explanatory drawing which shows typically the cross section of an example of the fuel cell of this invention. It is explanatory drawing which shows typically the cross section of an example of the chemical sensor of this invention.

Explanation of symbols

  100; proton conducting membrane, 110; mold part, 111; one surface of mold part, 112; opposite surface of mold part, 113; through hole, 120; porous part, 121; pore, 200; Agent, 300; micelle, 401; sol, 402; gel, 500; fuel cell, 600; chemical sensor, 700; heater, 801; sealed container, 802; open container, P1; sol preparation process, P2; P3: sol preliminary permeation step, P4: sol immersion permeation step, P5: gelation step, P6: structure directing agent removal step.

Claims (11)

A mold part having a plurality of through holes penetrating from one surface to the opposite surface;
A proton conductive membrane comprising: a porous portion filled in each through-hole and penetrating from the one surface to the opposite surface and having a plurality of pores having a smaller diameter than the through-hole.   The proton conductive membrane according to claim 1, wherein the through holes are aligned and arranged from the one surface toward the opposite surface.   The proton conductive membrane according to claim 1 or 2, wherein the pores are aligned and arranged from the one surface of the mold part toward the opposite surface.   The proton conductive membrane according to claim 1, wherein the porous portion has a silicon oxide skeleton.   The proton conductive membrane according to any one of claims 1 to 4, wherein the porous portion is subjected to phosphoric acid treatment.   6. The proton conductive membrane according to claim 1, wherein the mold part is anodized aluminum.   The proton conductive membrane according to claim 1, wherein the mold part is cellulose nitride. A method for producing a proton conducting membrane according to claim 1, comprising:
A sol filling step of filling a sol containing a structure-directing agent in the through hole of the mold part;
A gelation step of gelling the sol;
A structure-directing agent removing step of removing the structure-directing agent from the gel to form the pores.   The method for producing a proton conductor according to claim 8, further comprising a phosphoric acid treatment step of phosphoric acid treating the porous portion.   A fuel cell comprising the proton conducting membrane according to claim 1.   A chemical sensor comprising the proton conductive membrane according to claim 1.