Titanium porous plate material, water electrolysis electrode, and water electrolysis device

Abstract

To provide a titanium porous plate capable of sufficiently contacting another adjacent member, and capable of favorably flowing a fluid such as liquid and gas to diffuse.SOLUTION: A titanium porous plate is composed of a sintered body of titanium or a titanium alloy. The titanium porous plate has a three-dimensional network structure having communication pores which open to the surface of the titanium porous plate, and communicate with inside pores. The titanium porous plate has a structure obtained by laminating a first layer and a second layer in a thickness direction where the average pore diameter of the second layer is larger than an average pore diameter of the first layer. The average pore diameter of the first layer is preferably 10 μm or smaller. The average pore diameter of the second layer is preferably within the range of 50 μm or larger and 600 μm or smaller.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a titanium porous plate that has excellent fluid permeability for liquids, gases, and other fluids and excellent contact properties with other members, and to a water electrolysis electrode and a water electrolysis apparatus that each include the titanium porous plate. [Background technology]

[0002] In recent years, as efforts to realize a hydrogen society have accelerated in order to move away from CO2 emissions, demand for hydrogen is expected to increase, and there is a need to develop technologies to produce hydrogen cheaply and efficiently using renewable energy. Water electrolysis devices are attracting attention as a candidate technology for hydrogen production, and there are several types, such as solid oxide water electrolysis devices (SOEC) and alkaline water electrolysis devices. Among these, solid polymer electrolysis devices (PEM) have the advantage of being able to operate at around 100°C, and having high electrolysis efficiency and high hydrogen purity at the time of generation.

[0003] The internal structure and components of a solid polymer water electrolysis cell consist of, for example, from the cathode side, a current collector plate (such as an Au-plated SUS plate) / gas diffusion layer (electrode): porous carbon / catalyst layer (Pt / C + ionomer) / ion exchange membrane (polymer material) / catalyst layer (Ir particles + ionomer) / gas diffusion layer (electrode): porous titanium / current collector plate (such as an Au-plated SUS plate).

[0004] The gas diffusion layer mentioned above is often called a GDL (gas diffusion layer), but it is also sometimes called an electrode because it carries current to the catalyst layer, which is the reaction site for the water electrolysis reaction. The properties required for the anode-side gas diffusion layer (electrode) are (1) the need to diffuse the raw material liquid water and the oxygen gas after water electrolysis, and (2) the need to not corrode in the severe corrosive environment that occurs during electrolysis. For this reason, titanium, which has excellent corrosion resistance, is used for the anode-side gas diffusion layer (electrode).

[0005] For example, examples of titanium materials used as electrodes include the titanium sintered body disclosed in Patent Document 1 and the titanium foam material disclosed in Patent Document 2. On the other hand, in the field of solid molecular fuel cells, for example, as shown in Patent Documents 3 and 4, a porous electrode consisting of two layers of a sheet and a sponge has been proposed in order to increase power generation efficiency. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6485967 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-138005 [Patent Document 3] Patent No. 3982356 [Patent Document 4] Special Publication No. 2020-524747 Summary of the Invention [Problem to be solved by the invention]

[0007] The titanium sintered body described in Patent Document 1 mentioned above does not have a sufficiently high porosity. Therefore, when the titanium sintered body is used as an electrode for a water electrolysis cell, liquid water as a raw material and oxygen gas after water electrolysis cannot be sufficiently diffused, and there is a risk that the electrolysis efficiency cannot be improved. Furthermore, the titanium foam material described in Patent Document 2 has high porosity, and therefore when used as an electrode in a water electrolysis cell, it is difficult to ensure a sufficient contact area with the catalyst, which may prevent improvement in electrolysis efficiency. Furthermore, Patent Documents 3 and 4 do not disclose a two-layered electrode made of titanium material, and the corrosion resistance is insufficient, so that the electrode cannot be used as an electrode for a water electrolysis cell.

[0008] The present invention has been made in light of the above circumstances, and aims to provide a titanium porous plate that can be brought into sufficient contact with adjacent members and that allows fluids such as liquids and gases to flow and diffuse well, as well as water electrolysis electrodes and a water electrolysis apparatus that each include the titanium porous plate. [Means for solving the problem]

[0009] In order to solve these problems and achieve the above-mentioned object, the titanium porous plate of the present invention is a titanium porous plate made of a sintered body of titanium or a titanium alloy, and the titanium porous plate has a three-dimensional network structure with interconnected pores that are open to the surface of the titanium porous plate and communicate with internal pores. The titanium porous plate has a structure in which a first layer and a second layer are laminated in the thickness direction, and the average pore diameter of the second layer is larger than that of the first layer, the average pore diameter of the first layer being 0.1 μm or more and 10 μm or less, and the average pore diameter of the second layer being 50 μm or more and 600 μm or less. The porosity of the second layer is in the range of 85% to 95%. It is characterized by the following.

[0010] This porous titanium plate has a structure in which a first layer and a second layer having a larger average pore diameter than the first layer are laminated in the thickness direction, ensuring a sufficient contact area with adjacent components through the first layer having a smaller average pore diameter. Furthermore, the laminate also has a second layer having a larger average pore diameter than the first layer, allowing fluids such as liquids and gases to flow and diffuse well.

[0011] before Since the average pore size of the first layer is limited to 10 μm or less, a sufficient contact area with other adjacent members can be ensured.

[0012] before The second layer has a relatively large average pore size of 50 μm or more and 600 μm or less, which allows fluids such as liquids and gases to flow smoothly and be sufficiently diffused.

[0013] Furthermore, in the titanium porous plate of the present invention, the porosity of the first layer is preferably within the range of 30% to 70%. In this case, since the porosity of the first layer is set within the range of 30% to 70%, it is possible to ensure a sufficient contact area with other adjacent members.

[0015] Furthermore, in the porous titanium plate of the present invention, it is preferable that the ratio t1 / t2 of the thickness t1 of the first layer to the thickness t2 of the second layer is within the range of 0.01 to 1.0. In this case, the ratio t1 / t2 of the thickness t1 of the first layer to the thickness t2 of the second layer is set within the range of 0.01 or more and 1.0 or less, so that the first layer can provide good contact with other components, and the second layer can allow fluids such as liquids and gases to flow well and be sufficiently diffused.

[0016] The water electrolysis electrode of the present invention is characterized by comprising the above-mentioned titanium porous plate material. The water electrolysis electrode having this configuration is made of the above-described titanium porous plate. Therefore, by disposing the first layer on the catalyst layer side, a contact area with the catalyst layer is ensured, improving the catalyst utilization efficiency. In addition, by allowing fluids such as liquids and gases to flow smoothly and be sufficiently diffused in the second layer, efficient and stable water electrolysis can be performed.

[0017] The water electrolysis device of the present invention is characterized by including the above-described water electrolysis electrodes. The water electrolysis electrode having this configuration includes the water electrolysis electrode made of the above-described titanium porous plate. Therefore, by disposing the first layer on the catalyst layer side, a contact area with the catalyst layer is ensured, improving the catalyst utilization efficiency. In addition, by allowing fluids such as liquids and gases to flow smoothly and be sufficiently diffused in the second layer, efficient and stable water electrolysis can be performed. [Effects of the Invention]

[0018] The present invention makes it possible to provide a titanium porous plate that can be in sufficient contact with adjacent members and that allows fluids such as liquids and gases to flow and diffuse well, as well as water electrolysis electrodes and a water electrolysis apparatus that are made of this titanium porous plate. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an explanatory diagram showing an example of a titanium porous plate according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a flow chart showing an example of a method for producing the titanium porous plate shown in FIG. [Figure 3] 1 is a schematic explanatory diagram of a water electrolysis device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a porous titanium plate, an electrode for water electrolysis, and a water electrolysis apparatus according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] The titanium porous plate 10 of this embodiment is used, for example, as a conductive member such as a cathode electrode of a polymer electrolyte fuel cell (PEFC), an anode electrode of a water electrolysis device, or an electrode material for a lithium ion battery or lithium ion capacitor. In this embodiment, as will be described later, the electrode is used as an electrode constituting a gas diffusion layer (GDL) of the water electrolysis device (water electrolysis apparatus) shown in FIG.

[0022] The porous titanium plate 10 of this embodiment has a three-dimensional network structure having interconnected pores that are open on the surface and communicate with the internal pores. The titanium porous plate 10 of this embodiment has a structure in which a first layer 11 and a second layer 12 having an average pore diameter larger than that of the first layer 11 are laminated in the thickness direction.

[0023] In this embodiment, the average pore diameter of the first layer 11 is preferably 10 μm or less. In this embodiment, the average pore size of the second layer 12 is preferably within the range of 50 μm or more and 600 μm or less. The average pore diameters of the first layer 11 and the second layer 12 were determined as equivalent circle diameters (diameters) determined from the cross-sectional areas of the pores observed in the X-ray CT images.

[0024] Furthermore, in this embodiment, it is preferable that the porosity of the first layer 11 is within the range of 30% to 70%. In this embodiment, the porosity of the second layer 12 is preferably in the range of 75% to 95%. The porosity of the first layer 11 and the second layer 12 can be calculated from an X-ray CT image and weight.

[0025] Furthermore, in this embodiment, it is preferable that the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is within the range of 0.01 to 1.0.

[0026] The reasons for specifying the laminated structure, the average pore diameter of the first layer 11 and the second layer 12, the porosity of the first layer 11 and the second layer 12, and the ratio of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 in the titanium porous plate material 10 of this embodiment as described above will be explained below.

[0027] (Laminated structure) As described above, the titanium porous plate 10 of this embodiment has a structure in which the first layer 11 and the second layer 12, which have different average pore diameters, are stacked in the thickness direction. In the first layer 11 having a small average pore diameter, it is possible to ensure a contact area with other adjacent members, while in the second layer 12 having a large average pore diameter, the flow of liquids and gases is promoted. Therefore, in the titanium porous plate 10 of this embodiment, it is possible to ensure a contact area with other adjacent members and to promote the diffusion of liquids and gases.

[0028] (average pore diameter of the first layer) In the titanium porous plate 10 of this embodiment, when the average pore diameter of the first layer 11 is 10 μm or less, the pore diameter is sufficiently small, making it possible to ensure a sufficient contact area with other adjacent components. Therefore, in this embodiment, it is preferable that the average pore diameter of the first layer 11 is set to 10 μm or less. The upper limit of the average pore diameter of the first layer 11 is preferably 9 μm or less, and more preferably 8 μm or less, while the lower limit of the average pore diameter of the first layer 11 is preferably 0.1 μm or more, and more preferably 0.2 μm or more.

[0029] (average pore size of the second layer) In the titanium porous plate 10 of this embodiment, when the average pore diameter of the second layer 12 is 50 μm or more, the flow of liquid and gas can be sufficiently promoted. On the other hand, when the average pore diameter of the second layer 12 is 600 μm or less, strength can be ensured and electrical conductivity with the first layer 11 is improved. Therefore, in this embodiment, it is preferable that the average pore diameter of the second layer 12 is set within the range of 50 μm or more and 600 μm or less. The lower limit of the average pore diameter of the second layer 12 is more preferably 75 μm or more, and even more preferably 100 μm or more. On the other hand, the upper limit of the average pore diameter of the second layer 12 is more preferably 550 μm or less, and even more preferably 500 μm or less.

[0030] (Porosity of the first layer) In the titanium porous plate 10 of this embodiment, when the porosity of the first layer 11 is 30% or more, the flow of liquid and gas can be sufficiently ensured even in the first layer 11. On the other hand, when the porosity of the first layer 11 is 70% or less, it is possible to ensure a sufficient contact area with other adjacent members. Therefore, in this embodiment, the porosity of the first layer 11 is preferably set within the range of 30% to 70%. The lower limit of the porosity of the first layer 11 is more preferably 35% or more, and even more preferably 40% or more. On the other hand, the upper limit of the porosity of the first layer 11 is more preferably 65% ​​or less, and even more preferably 60% or less.

[0031] (Porosity of the second layer) In the titanium porous plate 10 of this embodiment, when the porosity of the second layer 12 is 75% or more, liquid and gas can flow more efficiently through the second layer 12. On the other hand, when the porosity of the second layer 12 is 95% or less, the strength of the second layer 12 can be ensured, and electrical conductivity with the first layer 11 is improved. Therefore, in this embodiment, the porosity of the second layer 12 is preferably set within the range of 75% to 95%. The lower limit of the porosity of the second layer 12 is more preferably 77% or more, and even more preferably 79% or more. On the other hand, the upper limit of the porosity of the second layer 12 is more preferably 93% or less, and even more preferably 90% or less.

[0032] (ratio of thickness of first layer to thickness of second layer 12) In the titanium porous plate 10 of this embodiment, when the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is 0.01 or greater, the thickness of the first layer 11 is ensured, and a sufficient contact area with adjacent components can be secured. Furthermore, the strength of the entire titanium porous plate 10 is ensured, improving handleability. On the other hand, when the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is 1.0 or less, the thickness of the second layer 12 is ensured, allowing for good flow of liquids and gases. Therefore, in this embodiment, it is preferable that the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is set within the range of 0.01 to 1.0. The lower limit of the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is more preferably 0.05 or more, and even more preferably 0.1 or more. On the other hand, the upper limit of the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is more preferably 0.9 or less, and even more preferably 0.8 or less.

[0033] Next, a method for manufacturing the titanium porous plate 10 according to this embodiment will be described with reference to the flow chart of FIG.

[0034] (Titanium-containing slurry formation step S01) First, titanium powder made of titanium or a titanium alloy is prepared as the raw material powder. In this embodiment, titanium hydride powder or pure titanium powder produced by dehydrogenating titanium hydride powder is prepared. This raw material powder is mixed with a water-soluble resin binder (methyl cellulose), an organic solvent (neopentane, hexane, and butane), a plasticizer (glycerin and ethylene glycol), water as a solvent, and in some cases a surfactant (alkylbenzene sulfonate) to produce a first titanium-containing slurry that will become the first layer 11. Furthermore, a water-soluble resin binder (methyl cellulose), an organic solvent (neopentane, hexane, and butane), a plasticizer (glycerin and ethylene glycol), water as a solvent, and optionally a surfactant (alkylbenzene sulfonate), as well as a foaming agent, are added to the raw material powder to prepare a second titanium-containing slurry that will become the second layer 12.

[0035] (Laminated sheet molding process S02) The obtained first titanium-containing slurry is used to form a first slurry layer on a zirconia plate by a doctor blade method, and then a second titanium-containing slurry is used to form a second slurry layer on the first slurry layer by a doctor blade method to obtain a laminated sheet compact.

[0036] (Foaming process S03) Next, while still on the zirconia plate, the mixture is fed into a high-temperature, high-humidity chamber, where it is maintained at a predetermined temperature and humidity to foam, and then dried with hot air to obtain a laminated green sheet compact.

[0037] (Degreasing process S04) Next, the laminated green sheet compact is placed on a zirconia plate and heated in a vacuum atmosphere to perform a degreasing treatment, thereby obtaining a degreased body.

[0038] (Sintering process S05) Next, the above-mentioned degreased body is cooled to 50°C or below in a vacuum atmosphere, and then sintered in a vacuum atmosphere without cooling, to obtain a sintered body in which a first layer 11 and a second layer 12 having different average pore diameters are laminated.

[0039] The porous titanium plate 10 of this embodiment is manufactured by the above-described manufacturing method.

[0040] Next, a schematic diagram of the water electrolysis electrodes and water electrolysis device of this embodiment is shown in Figure 3. The water electrolysis device of this embodiment is a solid polymer water decomposition device that has high electrolysis efficiency and high purity of hydrogen during generation.

[0041] 3, the water electrolysis device 30 of this embodiment includes a water electrolysis cell 31 including an anode 32 and a cathode 33 arranged opposite to each other, and an ion-permeable membrane 34 arranged between the anode 32 and the cathode 33. Catalyst layers 35 and 36 are formed on both surfaces of the ion-permeable membrane 34 (the surface in contact with the anode 32 and the surface in contact with the cathode 33), respectively. Here, the cathode 33, the ion-permeable membrane 34, and the catalyst layers 35 and 36 may be those used in a conventional general solid polymer water electrolysis device.

[0042] The anode 32 is the water electrolysis electrode of this embodiment. The anode 32 (water electrolysis electrode) is made of the titanium porous plate 10 of this embodiment. The anode 32 (water electrolysis electrode) is arranged so that the first layer 11 faces the catalyst layer 35.

[0043] 3, in the above-described water electrolysis device 30 (water electrolysis cell 31), water (H2O) is supplied from the anode electrode 32 side, and electricity is applied to the anode electrode 32 and the cathode electrode 33. Then, oxygen (O2) generated by the electrolysis of water is discharged from the anode electrode 32, and hydrogen (H2) is discharged from the cathode electrode 33.

[0044] As described above, water (liquid) and oxygen (gas) flow through the anode 32, and therefore, a high porosity is preferable to ensure stable flow of these liquids and gases. Furthermore, since the reaction in the anode 32 is promoted by contact with the catalyst layer 35, it is preferable to ensure a sufficient contact area with the catalyst layer 35. Furthermore, since the anode 32 is exposed to oxygen, it is required to have excellent corrosion resistance. Therefore, the water electrolysis electrode made of the titanium porous plate 10 of this embodiment is particularly suitable as the anode 32.

[0045] In the titanium porous plate 10 of this embodiment configured as described above, the first layer 11 and the second layer 12, which have different average pore diameters, are stacked in the thickness direction, and the average pore diameter of the second layer 12 is larger than that of the first layer 11. Therefore, the first layer 11, which has a smaller average pore diameter, can ensure a large contact area with the adjacent member (catalyst layer 35). In addition, the second layer 12, which has a larger average pore diameter, allows fluids such as liquids and gases to flow and diffuse well.

[0046] In the titanium porous plate of this embodiment, if the average pore diameter of the first layer 11 is 10 μm or less, a sufficient contact area with the adjacent member (catalyst layer 35) can be ensured. Furthermore, in the titanium porous plate of this embodiment, when the average pore diameter of the second layer 12 is within the range of 50 μm or more and 600 μm or less, the average pore diameter of the second layer 12 is set to be relatively large, so that fluids such as liquids and gases can flow well and be sufficiently diffused.

[0047] Furthermore, in the titanium porous plate of this embodiment, when the porosity of the first layer 11 is within the range of 30% or more and 70% or less, a sufficient contact area with other adjacent members (catalyst layer 35) can be ensured. Furthermore, in the titanium porous plate of this embodiment, when the porosity of the second layer 12 is within the range of 75% or more and 95% or less, fluids such as liquids and gases can be circulated well and diffused sufficiently.

[0048] Furthermore, in the titanium porous plate of this embodiment, when the ratio t1 / t2 of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is within the range of 0.01 or more and 1.0 or less, the first layer 11 can provide good contact with other components, and the second layer 12 can allow fluids such as liquids and gases to circulate well and be sufficiently diffused.

[0049] The water electrolysis electrode of this embodiment is made of the above-described titanium porous plate 10 and is used as the anode 32. Therefore, by disposing the first layer 11 on the catalyst layer 35 side, a sufficient contact area with the catalyst layer 35 is ensured, improving the catalyst utilization efficiency. In addition, by allowing fluids such as liquids and gases to flow smoothly and be sufficiently diffused in the second layer 12, efficient and stable water electrolysis can be performed.

[0050] In the water electrolysis apparatus 30 of the present embodiment, a water electrolysis electrode formed from the above-described titanium porous plate 10 is used as the anode 32. This ensures excellent catalyst utilization efficiency and allows fluids such as liquids and gases to circulate and diffuse satisfactorily, enabling efficient and stable water electrolysis.

[0051] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention. For example, in the present embodiment, the water electrolysis device (water electrolysis cell) having the structure shown in FIG. 3 has been described as an example, but the present invention is not limited to this, and water electrolysis devices (water electrolysis cells) having other structures may be used as long as they include water electrolysis electrodes made of the titanium porous plate material of the present embodiment. The porous titanium plate of the present invention may also be used for purposes other than water electrolysis devices. [Example]

[0052] The results of confirmation experiments conducted to confirm the effects of the present invention will be described below. In Examples 1-5 of the present invention, porous titanium plates were manufactured according to the procedures described in the "Examples" section. Titanium hydride powder with an average particle size of 15 μm and pure titanium powder with an average particle size of 10 μm were prepared as raw material powders. Furthermore, methyl cellulose was prepared as a water-soluble resin binder, neopentane, hexane, and butane were prepared as organic solvents, glycerin and ethylene glycol were prepared as plasticizers, water was prepared as a solvent, and alkylbenzene sulfonate was prepared as a surfactant.

[0053] The titanium hydride powder prepared earlier, methyl cellulose as a water-soluble resin binder, neopentane, hexane, and heptane as organic solvents, glycerin and ethylene glycol as plasticizers, and water as a solvent were blended, and alkylbenzene sulfonate as a surfactant was added as needed, and the mixture was kneaded for 15 minutes to prepare a first titanium-containing slurry. Using the same procedure as above, second titanium-containing slurries were prepared with different mixing ratios of raw material powder, foaming agent, plasticizer, and solvent.

[0054] Using the obtained first titanium-containing slurry, a first slurry layer was formed on a zirconia plate by a doctor blade method with a blade gap of 0.4 mm. Using the first titanium-containing slurry, a second slurry layer was laminated on the first slurry layer by the above-mentioned doctor blade method, thereby forming a laminated sheet compact. This laminated sheet molding was placed on a zirconia plate and then fed into a high-temperature, high-humidity chamber, where it was foamed at a temperature of 40°C and a humidity of 90% for 20 minutes, and then hot-air dried at a temperature of 80°C for 15 minutes to produce a laminated green sheet molding. This laminated green sheet compact was degreased and sintered at 1170°C for 10 hours to obtain a titanium porous plate.

[0055] In Example 6 of the present invention, a titanium sheet material produced using a titanium-containing slurry and a titanium fiber sintered compact made by sintering titanium fibers were placed on top of a zirconia plate, and diffusion bonded at 1000°C for 10 hours in a vacuum atmosphere.

[0056] In Comparative Example 1, a single layer of sintered titanium fiber compact was used, and in Comparative Examples 2 and 3, a single layer of titanium sheet material was used.

[0057] The porous titanium plates of Examples 1-6 and Comparative Examples 1-3 were evaluated for the following items. The evaluation results are shown in Table 1.

[0058] (average pore diameter) A sample for cross-sectional observation was taken from the titanium porous plate material, and a cross-sectional image of the sample was taken by X-ray fluoroscopy. The circle-equivalent diameter (diameter) was calculated from the area of ​​the observed pores.

[0059] (Porosity) A sample for cross-sectional observation was taken from the porous titanium plate material, and a 3D cross-sectional image of this sample was taken using X-ray fluoroscopy. For the second layer 12, which has an average pore diameter of 50 μm or more, the skeletal portion and pore portion were classified using binarization processing from the 3D cross-sectional image, and the porosity (P2) and volume V2 were calculated. On the other hand, the porosity (P1) of the first layer 11, which has a small pore diameter, was calculated using the following formula. P1=(1-W1 / (V1×D T )) W1: Mass (g) of the first layer 11 of the titanium porous plate 10 V1: Volume (cm 3 ) of the first layer 11 of the titanium porous plate 10 3 ) D T : True density (g / cm) of titanium constituting the titanium porous plate material 10 3 ) Here, W1 was calculated by the following formula using the mass Wa of the porous titanium plate 10 measured by an electronic balance and the above V2. W1=Wa -V2×(1-P2)×D T Wa: Mass of titanium porous plate 10 (g) V2: Volume (cm 3 ) of the second layer 12 of the titanium porous plate 10 3 ) P2: Porosity of the second layer 12 of the titanium porous plate 10

[0060] (Electrolysis efficiency) Using each of the titanium substrates described above as an anode, a solid polymer water electrolysis cell (area 4 cm × 4 cm) with the structure shown in Figure 3 was constructed. With pure water supplied to the anode, a voltage of 2.5 V was applied between the anode and cathode of the water electrolysis cell, and the current density flowing through the cell due to water electrolysis was measured. The electrolysis efficiency ratio was calculated from the ratio of these values. The test temperature was 80°C.

[0061] [Table 1]

[0062] It was confirmed that the titanium porous plate material of Example 1-6 of the present invention, which has a laminated structure of a first layer and a second layer with different average pore diameters, had improved electrolysis efficiency compared to the titanium porous plate material of Comparative Example 1-3, which has a single-phase structure.

[0063] From the above results, it was confirmed that the present invention can provide a titanium porous plate material that can be in sufficient contact with other adjacent components and that can allow fluids such as liquids and gases to flow and diffuse well. [Explanation of symbols]

[0064] 10. Titanium porous plate 11 1st layer 12 2nd layer 30 Water electrolysis equipment 32 Anode electrode (electrode for water electrolysis)

Claims

1. A titanium porous plate made of a sintered body of titanium or a titanium alloy, The titanium porous plate has a three-dimensional network structure having interconnected pores that are open on the surface of the titanium porous plate and communicate with internal pores; The titanium porous plate has a structure in which a first layer and a second layer are laminated in a thickness direction, and the average pore diameter of the second layer is larger than the average pore diameter of the first layer, the first layer has an average pore diameter of 0.1 μm or more and 10 μm or less, and the second layer has an average pore diameter of 50 μm or more and 600 μm or less; A titanium porous plate material characterized in that the porosity of the second layer is in the range of 85% to 95%.

2. 2. The titanium porous plate according to claim 1, wherein the porosity of the first layer is in the range of 30% to 70%.

3. 3. The titanium porous plate according to claim 1, wherein the ratio t1 / t2 of the thickness t1 of the first layer to the thickness t2 of the second layer is in the range of 0.01 to 1.

0.

4. An electrode for water electrolysis, characterized in that it is made of a titanium porous plate material described in any one of claims 1 to 3.

5. A water electrolysis device characterized by comprising the water electrolysis electrode described in claim 4.

Images