JP2020064784A - Electrode and electrode manufacturing method - Google Patents

Abstract

To provide an electrode which can have a platinum group metal content as low as possible, has excellent catalytic activity, and can be used as an anode or a cathode.SOLUTION: An electrode 10 is constituted by a platinum group metal and at least three kinds of transition metals from among various transition metals such that a synthetic work function approximates to a work function of the platinum group element, and is formed into a thin plate shape having a porous structure in which a large number of fine channels are formed by firing a compacted metal fine powder obtained by compressing, into a thin plate with a predetermined area, a metal fine powder mixture in which platinum group metal fine powder obtained by finely pulverizing the platinum group metal and a transition metal fine powder obtained by finely pulverizing at least three selected transition metals are uniformly mixed and dispersed. In the electrode 10, the weight ratio of the transition metals to the total weight of the fine metal powder mixture is set such that the synthetic work function approximates the work function of the platinum group element.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrode used as an anode or a cathode and an electrode manufacturing method for manufacturing an electrode used as an anode or a cathode.

  A fuel cell electrode in which platinum is supported on nitrogen-doped carbon obtained by firing a porous metal complex (PCP / MOF) containing zinc which is a low boiling point metal is disclosed (see Patent Document 1). Since this fuel cell electrode uses a porous metal complex (PCP / MOF) containing zinc, which is a low boiling point metal, as a manufacturing raw material, it contains almost no metal derived from the raw material and is a catalyst carrier which is NDC having a large specific surface area. And a highly active platinum catalyst can be obtained by supporting a small amount of platinum. Further, since the metal derived from the porous metal complex (PCP / MOF), which is a manufacturing raw material, is not included, the firing conditions can be freely set. That is, by changing the organic compound linker of the porous metal complex (PCP / MOF) used as a raw material and adjusting the firing temperature, it becomes possible to control the nitrogen content and crystallinity in the obtained NDC.

JP, 2008-23929, A

  Various platinum-supported carbons are widely used as electrode catalysts for polymer electrolyte fuel cells. However, since platinum is a precious metal and is a rare metal resource with a limited production amount, it is required to suppress its use. Further, in order to popularize polymer electrolyte fuel cells in the future, it is required to reduce the content of expensive platinum as much as possible and to develop an electrode using a metal other than platinum together with a small amount of platinum.

  An object of the present invention is to provide an electrode which can be used as an anode or a cathode having a platinum group metal content as small as possible and has an excellent catalytic activity (catalytic action), and an electrode manufacturing method of the electrode. To do. Another object of the present invention is to be able to generate sufficient electricity in a fuel cell, to supply sufficient electric energy to a load connected to the fuel cell, and to efficiently perform electrolysis in a hydrogen gas generator. An object of the present invention is to provide an electrode that can be well performed and can generate a large amount of hydrogen gas in a short time, and an electrode manufacturing method of the electrode.

  The first premise of the present invention for solving the above problems is an electrode used as an anode or a cathode.

  The feature of the electrode of the present invention on the first premise is that the electrode is at least one platinum group metal selected from various platinum group metals, and at least three transition metal selected from various transition metals. A metal in which at least one selected platinum group metal is finely pulverized, and at least three selected transition metals are finely pulverized, and a transition metal fine powder is uniformly mixed and dispersed. This is because the fine powder mixture is compressed into a thin plate having a predetermined area and then fired to form a thin plate having a porous structure in which a large number of fine channels are formed.

  As an example of the electrode of the present invention, in the electrode, at least three kinds of transition metals are selected so that the composite work function of the work functions of the selected at least three kinds of transition metals approximates the work function of the platinum group element. Selected transition metals.

  As another example of the electrode of the present invention, the thickness dimension of the electrode is in the range of 0.03 mm to 0.8 mm.

  As another example of the electrode of the present invention, the transition metals are Ni (nickel) and Fe (iron) and Cu (copper) having the lowest melting point, and the electrode has a work function of Ni and a work function of Fe. The weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture and the total weight of the Fe fine powder to the metal fine powder mixture so that the composite work function with the work function of Cu approximates the work function of the platinum group element. And a weight ratio of Cu fine powder to the total weight of the metal fine powder mixture.

  As another example of the electrode of the present invention, the weight ratio of the platinum group metal fine powder to the total weight of the metal fine powder mixture is in the range of 5 to 10%, and the weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture is 5 to 10%. The weight ratio is in the range of 30% to 45%, the weight ratio of Fe fine powder to the total weight of the metal fine powder mixture is 30% to 45%, and the weight ratio of Cu fine powder is to the total weight of the metal fine powder mixture. The weight ratio is in the range of 3% to 5%.

  As another example of the electrode of the present invention, the porosity of the electrode formed into a thin plate having a porous structure is in the range of 15% to 30%.

As another example of the electrode of the present invention, the density of the electrode which is formed into a thin plate of a porous structure ^is in the range of ^{5.0g / cm 2 ~7.0g / cm 2} .

  As another example of the electrode of the present invention, the particle size of the platinum group metal fine powder and the particle size of the transition metal fine powder are in the range of 10 μm to 200 μm.

  As another example of the electrode of the present invention, in the electrode, the fine powder of Cu having the highest melting point is melted at the time of firing the metal fine powder mixture compressed into a thin plate having a predetermined area, and the fine powder of the platinum group metal is formed by using the molten Cu as a binder. The body, Ni fine powder, and Fe fine powder are joined together.

  The second premise of the present invention for solving the above problems is an electrode manufacturing method for manufacturing an electrode used as an anode or a cathode.

  The feature of the electrode manufacturing method of the present invention in the second premise is that the electrode manufacturing method selects at least one kind of platinum group metal from among various kinds of platinum group metals, and selects at least three kinds from various kinds of transition metals. A transition metal selection step of selecting at least three kinds of transition metals from various transition metals so that the composite work function of the transition metals of A fine metal powder for finely pulverizing at least one selected platinum group metal to produce a fine platinum group metal powder, and finely pulverizing at least three kinds of transition metals selected in the transition metal selection step to produce a fine transition metal powder. So that the composite work function of at least three kinds of transition metal fine powders produced by the body forming step and the metal fine powder forming step approximates the work function of the platinum group element, A fine powder weight ratio determining step for determining a weight ratio of the gold group metal fine powder and a weight ratio of at least three kinds of transition metal fine powders; and a platinum group metal fine powder having a weight ratio determined by the fine powder weight ratio determining step. A metal fine powder mixture producing process for producing a metal fine powder mixture in which at least three kinds of transition metal fine powders are mixed and dispersed, and a metal fine powder mixture produced by the metal fine powder mixture producing process is pressurized at a predetermined pressure to produce a metal. It has a porous structure in which a large number of fine flow paths are formed by firing a metal fine powder compressed product for making a fine powder compressed product and firing the metal fine powder compressed product made by the metal fine powder compressed product production process at a predetermined temperature. And a step of producing a thin plate electrode having a porous structure for producing an electrode formed into a thin plate shape.

  As an example of the electrode manufacturing method of the present invention, the transition metals selected in the transition metal selection step are Ni (nickel), Fe (iron), and Cu (copper) having the lowest melting point, and the fine powder weight ratio is determined. In the step, the weight ratio of the platinum group metal fine powder to the total weight of the metal fine powder mixture is determined in the range of 5 to 10%, and the weight ratio of Ni fine powder to the total weight of the metal fine powder mixture is 30% to 30%. The weight ratio of Fe fine powder to the total weight of the metal fine powder mixture is determined in the range of 45%, and the weight ratio of Cu fine powder to the total weight of the metal fine powder mixture is determined in the range of 30% to 45%. The ratio is determined in the range of 3% to 5%.

  As another example of the electrode manufacturing method of the present invention, in the metal fine powder forming step, the platinum group metal is finely pulverized to have a particle diameter of 10 μm to 200 μm, and the transition metal is finely pulverized to have a particle diameter of 10 μm to 200 μm.

  As another example of the electrode manufacturing method of the present invention, in the metal fine powder compressed material producing step, the metal fine powder mixture produced in the metal fine powder mixture producing step is pressurized at a pressure of 500 Mpa to 800 Mpa to give 0.03 mm to A thin plate-like compacted metal fine powder having a porous structure having a thickness of 0.8 mm and forming a large number of fine channels is produced.

  As another example of the electrode manufacturing method of the present invention, in the porous structure thin plate electrode forming step, the metal fine powder compact is fired at a temperature at which the Cu fine powder having the lowest melting point is melted, and the molten Cu fine powder is obtained. As a binder, a fine powder of platinum group metal, a fine powder of Ni and a fine powder of Fe are bonded together.

  According to the electrode of the present invention, it is formed and selected from at least one platinum group metal selected from various platinum group metals and at least three transition metal selected from various transition metals. A metal fine powder mixture in which a platinum group metal fine powder obtained by finely pulverizing at least one kind of platinum group metal and a transition metal fine powder obtained by finely pulverizing at least three kinds of selected transition metals are uniformly mixed and dispersed in a predetermined area It is a thin plate electrode with a porous structure that is compressed into a thin plate and then fired to form a number of fine flow paths (passage holes). By using a transition metal other than the platinum group metal, the platinum group metal content can be increased. By using the catalytic activity of the platinum group metal and the catalytic activity of the transition metal, the anode or the cathode containing a small amount of the platinum group metal having excellent catalytic activity (catalysis) can be used. It can be used as a.

  An electrode in which at least three kinds of transition metals are selected from various kinds of transition metals so that the composite work function of the work functions of the selected at least three kinds of transition metals approximates the work function of the platinum group element, Since at least three kinds of transition metals are selected from among various kinds of transition metals so that the synthetic work function approximates to the work function of the platinum group element, the electrode has a small content even though the platinum group metal content is low. It has a work function that is almost the same as that of the electrode that supports the platinum group element, and it can exhibit the same catalytic activity (catalytic action) as the electrode that supports the platinum group element, so that the catalytic function can be used sufficiently and reliably. It can be used as an anode or a cathode containing a small amount of platinum group metal having excellent catalytic activity (catalytic action). Since the electrode exhibits substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, by using the electrode in the fuel cell, sufficient electricity can be generated in the fuel cell, Sufficient electric energy can be supplied to the load connected to the fuel cell, and by using the electrodes in the hydrogen gas generator, electrolysis can be efficiently performed in the hydrogen gas generator, and in a short time. A large amount of hydrogen gas can be generated.

  An electrode having a thickness dimension in the range of 0.03 mm to 0.8 mm can reduce the electric resistance of the electrode by setting the thickness dimension of the electrode in the above range, and a current can be smoothly passed through the electrode. . The electrode has almost the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, and the current flows smoothly through it, so using the electrode in the fuel cell ensures sufficient electricity in the fuel cell. Can generate electric power, can supply sufficient electric energy to the load connected to the fuel cell, and can efficiently perform electrolysis in the hydrogen gas generator by using the electrode in the hydrogen gas generator. Therefore, a large amount of hydrogen gas can be generated in a short time.

  The transition metals are Ni (nickel) and Fe (iron) and Cu (copper) having the lowest melting point, and the work function of the platinum group element is the composite work function of the work function of Ni, the work function of Fe and the work function of Cu. As approximate to the function, the weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture, the weight ratio of the Fe fine powder to the total weight of the metal fine powder mixture, and the total weight ratio of the Cu fine powder to the metal fine powder mixture are For the electrode whose weight ratio to weight is determined, Ni (nickel), Fe (iron), and Cu (copper) whose synthetic work function approximates the work function of the platinum group element are selected, and the synthetic work function is Since the weight ratio of the Ni fine powder, the Fe fine powder, and the Cu fine powder to the total weight of the metal fine powder mixture is determined so as to approximate the work function of the platinum group element, Even if the content of group metals is low However, the electrode has substantially the same work function as the electrode supporting the platinum group element, and can exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, and the catalytic function is sufficient. It can be reliably used and can be suitably used as an anode or a cathode containing a small amount of platinum group metal having excellent catalytic activity (catalytic action). Since the electrode exhibits substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, by using the electrode in the fuel cell, sufficient electricity can be generated in the fuel cell, Sufficient electric energy can be supplied to the load connected to the fuel cell, and by using the electrodes in the hydrogen gas generator, electrolysis can be efficiently performed in the hydrogen gas generator, and in a short time. A large amount of hydrogen gas can be generated.

  The weight ratio of the platinum group metal fine powder to the total weight of the metal fine powder mixture is in the range of 5 to 10%, the weight ratio of Ni fine powder to the total weight of the metal fine powder mixture is in the range of 30% to 45%, Fe An electrode having a weight ratio of the fine powder of 3 to 5% to the total weight of the metal fine powder mixture and a weight ratio of Cu fine powder to the total weight of the metal fine powder mixture of 3% to 5% is , Ni (nickel), Fe (iron), and Cu (copper) whose synthetic work function approximates the work function of the platinum group element, and so that the synthetic work function approximates the work function of the platinum group element, Since the weight ratio of the Ni fine powder, the Fe fine powder, and the Cu fine powder to the total weight of the metal fine powder mixture is determined within the above range, even if the platinum group metal content is low. However, the electrode is It has a work function almost the same as the above, and can exhibit a catalytic activity (catalytic action) similar to that of an electrode supporting a platinum group element, and it is possible to sufficiently and surely utilize the catalytic function, which is excellent. It can be suitably used as an anode or a cathode containing a small amount of platinum group metal having catalytic activity (catalytic action). The electrode contains an inexpensive transition metal selected from various transition metals, and the weight ratio of the fine Ni powder, the fine Fe powder, and the fine Cu powder to the total weight of the fine metal powder mixture. The ratio is in the above range, the weight ratio of the fine powder of the platinum group metal to the total weight of the fine metal powder mixture is in the range, and the content of the expensive platinum group metal is small, so that the anode or the cathode can be made inexpensively. You can Since the electrode exhibits substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, by using the electrode in the fuel cell, sufficient electricity can be generated in the fuel cell, Sufficient electric energy can be supplied to the load connected to the fuel cell, and by using the electrodes in the hydrogen gas generator, electrolysis can be efficiently performed in the hydrogen gas generator, and in a short time. A large amount of hydrogen gas can be generated.

  For an electrode having a porous structure formed in the shape of a thin plate and having a porosity in the range of 15% to 30%, by setting the porosity of the electrode within the above range, the thin plate-shaped electrode has a large number of fine flow paths ( It is possible to increase the specific surface area of the electrode by allowing the gas or the liquid to flow through these channels and widely contact the contact surface of the electrode with the gas or the liquid. It is possible to reliably exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element. The electrode can be suitably used as an anode or a cathode containing a small amount of a platinum group metal that can sufficiently and reliably utilize its catalytic function and has excellent catalytic activity (catalytic action).

The density of thin plate shaped electrodes of porous structure is in the range of 5.0g ^/ cm ² ~7.0g / cm 2 electrode, by the density of the electrode in the range, thin plate-like electrodes are a number of Molded into a porous structure with minute flow passages (passage holes), the specific surface area of the electrode can be increased, and while the gas or liquid flows through these flow passages, the gas or liquid is brought into wide contact with the contact surface of the electrode. Therefore, it is possible to surely exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element. The electrode can be suitably used as an anode or a cathode containing a small amount of a platinum group metal that can sufficiently and reliably utilize its catalytic function and has excellent catalytic activity (catalytic action).

  An electrode in which the particle size of the fine powder of the platinum group metal and the particle size of the fine powder of the transition metal are in the range of 10 μm to 200 μm is obtained by setting the particle size of the fine powder of the platinum group metal and the transition metal in the above range, The thin plate-shaped electrode is formed into a porous structure having a large number of minute flow paths (passage holes), and the specific surface area of the electrode can be increased. It is possible to make a wide contact with the contact surface of, and it is possible to reliably exhibit substantially the same catalytic activity (catalytic action) as the electrode carrying the platinum group element. The electrode can be suitably used as an anode or a cathode containing a small amount of a platinum group metal that can sufficiently and reliably utilize its catalytic function and has excellent catalytic activity (catalytic action).

  The fine powder of Cu having the highest melting point is melted at the time of firing the metal fine powder mixture compressed into a thin plate having a predetermined area, and the fine powder of platinum group metal, the fine powder of Ni and the fine powder of Fe are formed by using the molten Cu as a binder. The electrode to be joined has high strength by joining the fine powder of platinum group metal, the fine powder of Ni and the fine powder of Fe with Cu fine powder having the lowest melting point as a binder. The shape can be maintained, and damage or destruction of the electrode when a shock is applied to the electrode can be prevented. Since the electrode can maintain its shape, it is suitable as an anode or a cathode containing a small amount of platinum group metal that can sufficiently and reliably utilize its catalytic function and has excellent catalytic activity (catalytic action). Can be used for

  According to the electrode manufacturing method of the present invention, at least one kind of platinum group metal is selected from various kinds of platinum group metals, and the work function of at least three kinds of transition metals selected from various kinds of transition metals is a composite work function. So as to approximate the work function of the platinum group element, a transition metal selecting step of selecting at least three kinds of transition metals from various transition metals, and at least one kind of platinum group metal selected by the transition metal selecting step. And a fine metal powder to produce a platinum group metal fine powder, and finely pulverize at least three kinds of transition metals selected in the transition metal selection step to produce a fine transition metal powder, and a fine metal powder production step Of the work function of at least three kinds of transition metal fine powders produced by the method, so that the work function approximates to the work function of the platinum group element, and the weight ratio of the platinum group metal fine powder and at least A fine powder weight ratio determining step of determining a weight ratio of three kinds of transition metal fine powders; a platinum group metal fine powder having a weight ratio determined by the fine powder weight ratio determining step and at least three kinds of transition metal fine powders. Metal fine powder mixture making process to make mixed and dispersed metal fine powder mixture, and metal fine powder mixture made by the metal fine powder mixture making process to press metal fine powder mixture at a predetermined pressure to make metal fine powder compressed product Porous substance forming process and porous metal thin electrode compacted product produced by the fine metal powder compressed product producing process are fired at a predetermined temperature to form a thin plate-like electrode having a porous structure in which a large number of fine flow paths are formed. Since the electrode is manufactured by each process of the structural thin plate electrode manufacturing process, the electrode can be manufactured at low cost, and it has excellent catalytic activity (catalytic action) and can fully and reliably utilize the catalytic function. You can make ability platinum group metal small-containing electrode (anode or cathode). The electrode manufacturing method produces an electrode capable of generating sufficient electricity in a fuel cell because the electrode produced thereby exhibits substantially the same catalytic activity (catalytic action) as the electrode carrying the platinum group element. Therefore, it is possible to produce an electrode that can efficiently perform electrolysis in the hydrogen gas generator and can generate a large amount of hydrogen gas in a short time.

  The transition metals selected in the transition metal selection step are Ni (nickel), Fe (iron), and Cu (copper) having the lowest melting point, and platinum is used for the total weight of the metal fine powder mixture in the fine powder weight ratio determination step. The weight ratio of the fine powder of the group metal is determined in the range of 5 to 10%, and the weight ratio of the fine powder of Ni to the total weight of the fine metal powder mixture is determined in the range of 30% to 45%. The weight ratio of the fine Fe powder to the total weight of Fe is determined in the range of 30% to 45%, and the weight ratio of the fine Cu powder to the total weight of the metal fine powder mixture is determined in the range of 3% to 5%. The electrode manufacturing method selects Ni (nickel), Fe (iron), and Cu (copper) whose synthetic work function approximates the work function of the platinum group element, and the synthetic work function approximates the work function of the platinum group element. So that the fine metal powder The weight ratio of the fine Ni powder, the fine Fe powder, and the fine Cu powder relative to the total weight of the compound is determined within the above range, so that the platinum group metal content is low. The electrode has a work function substantially the same as that of the electrode supporting the platinum group element, and can exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element and excellent catalytic activity (catalyst). It is possible to produce an electrode (anode or cathode) containing a small amount of platinum group metal that has a function) and can utilize the catalytic function sufficiently and reliably. The electrode manufacturing method is such that the weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture, the weight ratio of the Fe fine powder, and the total weight of the Cu fine powder are within the above ranges, and the total weight of the metal fine powder mixture is Since the weight ratio of the platinum group metal fine powder is within the above range, the content of the expensive platinum group metal is small, and the anode or the cathode can be manufactured at low cost.

  In the metal fine powder preparation step, the platinum group metal is pulverized to a particle size of 10 μm to 200 μm, and the transition metal is pulverized to a particle size of 10 μm to 200 μm. By pulverizing and pulverizing the transition metal to a particle size within the above range, a thin plate-like electrode having a porous structure with a large specific surface area is formed by forming a porous structure having a large number of fine channels (passage holes). It is possible to bring the gas or liquid into wide contact with the contact surface of the electrode while allowing the gas or liquid to flow through these flow paths, and to achieve substantially the same catalytic activity (catalytic action) as the electrode carrying the platinum group element. It is possible to make an electrode that can surely exhibit. The electrode manufacturing method is an electrode containing a small amount of a platinum group metal that can sufficiently and surely utilize a catalytic function and has excellent catalytic activity (catalytic action) and can be used as an anode or a cathode. Can be made.

  In the metal fine powder compressed material producing step, the metal fine powder mixture produced in the metal fine powder mixture producing step is pressurized at a pressure of 500 Mpa to 800 Mpa, and has a thickness dimension of 0.03 mm to 0.8 mm and a large number of fine particles. An electrode manufacturing method for producing a compressed metal fine powder having a porous structure and a thin plate in which various flow paths are formed is such that the metal fine powder mixture is pressed (compressed) at a pressure within the above range to have a thickness dimension of 0.03 mm to It is possible to form a thin plate electrode having a porous structure of 0.8 mm and having a large number of fine flow passages (passage holes), and it is possible to inexpensively manufacture a thin plate electrode having a porous structure and an excellent catalyst. An electrode (anode or cathode) containing a small amount of platinum group metal that has an activity (catalyst action) and can sufficiently and reliably utilize the catalytic function can be produced. In the electrode manufacturing method, an electrode having a thickness dimension in the range of 0.03 mm to 0.8 mm can be manufactured, and thus an electrode (anode or cathode) having a small electric resistance and capable of smoothly flowing a current can be manufactured. .

  In the step of forming a thin plate electrode having a porous structure, a compressed metal fine powder is fired at a temperature at which the fine Cu powder having the lowest melting point is melted, and the molten Cu fine powder is used as a binder for the platinum group metal fine powder and the Ni fine powder. The electrode manufacturing method for joining the fine powder of Fe and the fine powder of Fe is performed by joining fine powder of platinum group metal, fine powder of Ni, and fine powder of Fe with Cu fine powder having the lowest melting point as a binder. It is possible to make a thin plate-shaped electrode with a porous structure having various flow passages (passage holes), maintain the shape with high strength, and prevent damage or damage when shock is applied. It is possible to make an electrode that can

The perspective view of the electrode shown as an example. The partial enlarged front view shown as an example of an electrode. The partial expanded front view shown as another example of an electrode. FIG. 3 is an exploded perspective view showing an example of a cell using electrodes. The side view of the cell using an electrode. The figure explaining the electric power generation of the polymer electrolyte fuel cell using an electrode. The figure which shows the result of the electromotive voltage test of an electrode. The figure which shows the result of the IV characteristic test of an electrode. The figure explaining electrolysis of the hydrogen gas generator which uses an electrode. 6A to 6C are views illustrating a method of manufacturing an electrode.

  Details of the electrode according to the present invention will be described below with reference to the accompanying drawings such as FIG. 1 which is a perspective view of the electrode 10 shown as an example. 2 is a partially enlarged front view showing an example of the electrode 10, and FIG. 3 is a partially enlarged front view showing another example of the electrode 10. In FIG. 1, the thickness direction is indicated by arrow X, and the radial direction is indicated by arrow Y.

  The electrode 10 is used as an anode or a cathode, and is used as a fuel electrode 18 (catalyst electrode) or an air electrode 19 (catalyst electrode) of the polymer electrolyte fuel cell 17 (see FIG. 6) and an anode 31 (electrode of the hydrogen gas generator 30). It is used as a catalyst) or a cathode 32 (electrode catalyst) (see FIG. 9). The electrode 10 has a front surface 11 and a rear surface 12, has a predetermined area and a predetermined thickness dimension L1, and its planar shape is formed into a quadrangle. The electrode 10 is a thin plate electrode having a porous structure (porous) having many fine flow paths 13 (passage holes). Gas or liquid flows through the flow path 13 (passage hole). The planar shape of the electrode 10 is not particularly limited, and in addition to the quadrangle, the electrode 10 can be molded into any other planar shape such as a circle, an ellipse, or a polygon according to the application.

  The electrode 10 is formed of a powder-processed platinum group metal 41 and at least three kinds of transition metals 42 selected from powder-processed transition metals 42. As the platinum group metal 41, platinum (Pt), palladium (Pb), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os) can be used. At least one of them is used for the platinum group metal 41. As the transition metal 42, 3d transition metal or 4d transition metal is used. Ti (titanium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), and Zn (zinc) are used as the 3d transition metal. Nb (niobium), Mo (molybdenum), and Ag (silver) are used as the 4d transition metal. At least three of them are used for the transition metal 42.

  In the electrode 10 (thin plate electrode having a porous structure), the composite work function of the work functions (energy necessary to extract electrons from the substance) of at least three types of selected transition metals 42 approximates the work function of the platinum group element. As described above, at least three kinds of transition metals 42 are selected from the transition metals 42. The work function of platinum is 5.65 (eV). The work function of Ti is 4.14 (eV), the work function of Cr is 4.5 (eV), the work function of Mn is 4.1 (eV), and the work function of Fe is 4.67 (eV). ), Co has a work function of 5.0 (eV), Ni has a work function of 5.22 (eV), Cu has a work function of 5.10 (eV), and Zn has a work function of 3.63. (EV) and Nb have work functions of 4.01 (eV), Mo has a work function of 4.45 (eV), and Ag has a work function of 4.31 (eV).

  The electrode 10 is a platinum group metal fine powder of the platinum group metal 41 (Pt (platinum) finely processed, Pb (palladium) finely powdered, Rh (rhodium) finely powdered, fine powdery) Processed into Ru (ruthenium), pulverized into Ir (iridium), pulverized into Os (osmium)), and at least three transition metals 42 selected from various transition metals 42. Fine powder of transition metal (Ti (titanium) processed into fine powder, Cr (chrome) processed into fine powder, Mn (manganese) processed into fine powder, Fe (iron) processed into fine powder, Fine powder processed Co (cobalt), fine powder processed Ni (nickel), fine powder processed Cu (copper), fine powder processed Zn (zinc), fine powder processed Nb (niobium) in fine powder form A fine metal powder compact compressed in a thin plate by compressing a fine metal powder mixture 51 obtained by uniformly mixing and dispersing processed Mo (molybdenum) and finely powdered Ag (silver) into a thin plate having a predetermined area. No. 52, and the fine metal powder compact 52 is fired at a predetermined temperature (see FIG. 10).

  In the electrode 10, the composite work function of the work functions of the selected three kinds of transition metals 42 is close to the work function of the platinum group element, with respect to the total weight of the fine metal powder mixture 51 of the fine particles of the platinum group metal 41. The weight ratio is determined, and the weight ratio of the fine powder of the transition metal 42 to the total weight of the fine metal powder mixture 51 is determined. Specifically, the weight ratio of the fine powder of platinum group metal 41 to the total weight (100%) of the fine metal powder mixture 51 is in the range of 5 to 10%, preferably in the range of 5 to 6%. The weight ratio of one kind of fine particles of the transition metal 42 to the total weight (100%) of the fine metal powder mixture 51 is in the range of 30% to 45%, preferably in the range of 40% to 45%. The weight ratio of the fine powder of the other one of the selected transition metals 42 to the total weight (100%) of the fine metal powder mixture 51 is in the range of 30% to 45%, preferably 40% to 45%. Within the range, the weight ratio of one type of fine powder other than the two types of the selected transition metals 42 to the total weight (100%) of the metal fine powder mixture 51 is in the range of 3% to 5%. , Preferably 4%. The transition metal 42 having a weight ratio of 3% to 5% has a melting point lower than that of the other two types of transition metals 42, and is used as a binder (joining component) for joining the other two types of transition metals 42. Become.

  Platinum group metal 41 fine powder weight ratio, selected one kind of transition metal 42 fine powder weight ratio, other selected one kind of transition metal 42 fine powder weight ratio, selection excluding two kinds If the weight ratio of the fine powder of the other transition metal 42 is out of the above range, the synthetic work function of the fine powder of the transition metal 42 cannot be approximated to the work function of the platinum group element, and the metal The electrode 10 formed by firing the compressed metal fine powder 52 obtained by compressing the fine powder mixture 51 cannot exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element.

  A large number of minute flow paths 13 (passage holes) having different diameters are formed in the electrode 10. The electrode 10 has a large specific surface area because a large number of fine flow paths 13 (passage holes) are formed therein. The flow paths 13 (passage holes) have a plurality of through holes 14 that open to the front surface 11 of the electrode 10 and a plurality of through holes 14 that open to the rear surface 12 of the electrode 10. The electrode 10 penetrates in the thickness direction toward the rear surface 12.

  The flow paths 13 extend between the front surface 11 and the rear surface 12 of the electrode 10 while irregularly bending in the thickness direction of the electrode 10, and the diameter of the electrode 10 increases from the outer peripheral edge 15 of the electrode 10 toward the center. It bends in an irregular direction and extends. The flow passages 13 that are adjacent to each other in the radial direction and extend by bending in the thickness direction are partially connected in the radial direction, and one flow passage 13 and the other flow passage 13 communicate with each other. The flow paths 13 that are adjacent to each other in the thickness direction and bend and extend in the radial direction are partially connected in the thickness direction, and one flow path 13 and the other flow path 13 communicate with each other.

The opening areas (opening diameters) of the flow paths 13 (passage holes) are not uniform in the thickness direction, are irregularly changed in the thickness direction, and are not uniform in the radial direction. , Irregularly changing in the radial direction. The flow paths 13 are irregularly opened in the thickness direction and the radial direction while the opening area (opening diameter) increases or decreases. Further, the opening area (opening diameter) of the through hole 14 opening to the front surface 11 of the electrode 10 and the opening area (opening diameter) of the opening surface to the rear surface 12 are not uniform, and the areas are all different. The opening diameters of the flow paths 13 (passage holes) and the opening diameters of the flow ports 14 of the front and rear surfaces 11 and 12 are in the range of 1 μm to 100 μm.
Since the electrode 10 is formed with a plurality of flow paths 13 (passage holes) that extend while irregularly bending in the thickness direction and the radial direction, the electrode 10 has a large specific surface area, and these flow paths 13 (passage holes) are formed. While the gas (gas) or liquid flows, the gas (gas) or liquid can be widely contacted with the contact surfaces of the flow paths 25 of the electrode 10, and the catalytic activity (catalytic action) of the electrode 10 can be effectively and maximized. Can be used.

  The electrode 10 (thin plate electrode having a porous structure) has a thickness dimension L1 in the range of 0.03 mm to 0.8 mm, preferably in the range of 0.05 mm to 0.5 mm. When the thickness dimension L1 of the electrode 10 is less than 0.03 mm (0.05 mm), its strength decreases, and the electrode 10 is easily broken or damaged when an impact is applied, and its shape cannot be maintained. There is. When the thickness dimension L1 of the electrode 10 exceeds 0.8 mm (0.5 mm), the electric resistance of the electrode 10 increases and the current does not flow smoothly to the electrode 10, and the electrode 10 is used for the polymer electrolyte fuel cell 17. In this case, the fuel cell 17 cannot generate sufficient electricity and the load 29 connected to the fuel cell 17 cannot be supplied with sufficient electric energy. Moreover, when the electrode 10 is used in the hydrogen gas generator 30, electrolysis cannot be efficiently performed, and the hydrogen gas generator 30 cannot generate a large amount of hydrogen gas in a short time.

  The electrode 10 (thin plate electrode having a porous structure) has a thickness dimension L1 of 0.03 mm to 0.8 mm, preferably 0.05 mm to 0.5 mm, and thus the electrode 10 has high strength. The shape of the electrode 10 can be maintained, and damage or destruction of the electrode 10 when a shock is applied to the electrode 10 can be prevented. Further, the electric resistance of the electrode 10 can be reduced, a current smoothly flows through the electrode 10, and when the electrode 10 is used in the polymer electrolyte fuel cell 17, sufficient electricity can be generated in the fuel cell 17. As a result, sufficient electric energy can be supplied to the load 29 connected to the fuel cell 17. Moreover, when the electrode 10 is used in the hydrogen gas generator 30, electrolysis can be efficiently performed, and a large amount of hydrogen gas can be generated in the hydrogen gas generator 30 in a short time.

  The electrode 10 has a porosity of 15% to 30%, preferably 20% to 25%, and a relative density of 70% to 85%, preferably 75% to 80%. In range. When the porosity of the electrode 10 is less than 15% and the relative density exceeds 85%, a large number of minute flow paths 13 (passage holes) are not formed in the electrode 10 and the specific surface area of the electrode 10 can be increased. Can not. When the porosity of the electrode 10 exceeds 30% and the relative density is less than 70%, the opening area (opening diameter) of the flow path 13 (passage hole) and the opening area (opening area) of the flow passages 14 of the front and rear surfaces 11, 12 are set. The diameter of the electrode 10 becomes unnecessarily large, the strength of the electrode 10 is reduced, and the electrode 10 may be easily damaged or damaged when an impact is applied, and its shape may not be maintained. The catalytic action is lowered and the catalytic activity cannot be exhibited.

  Since the porosity and the relative density of the electrode 10 are within the above ranges, the electrode 10 has a large number of minute flow paths 13 (passage holes) having different opening areas (opening diameters) and a large number of different opening areas (opening diameters). The electrode 10 is formed into a porous body having minute front and rear surfaces 11 and 12 through which the gas flows, and the specific surface area of the electrode 10 can be increased. The liquid can widely contact the contact surfaces of the electrodes 10 in the flow paths 13. Further, the catalytic action of the electrode 10 is improved, and excellent catalytic activity can be exhibited.

Electrode 10 ranges its density is ^{5.0g / cm 2 ~7.0g / cm 2} , ^preferably in the range of ^{5.5g / cm 2 ~6.5g / cm 2} . When the density of the electrode 10 is less than 5.0 g / cm ² , the strength of the electrode 10 is reduced, and the electrode 10 may be easily broken or damaged when an impact is applied, and the shape thereof may not be maintained. At the same time, the catalytic action of the electrode 10 is lowered and the catalytic activity cannot be exhibited. When the density of the electrode 10 exceeds 7.0 g / cm ² , many fine flow paths 13 (passage holes) are not formed in the electrode 10, the specific surface area of the electrode 10 cannot be increased, and The catalytic action is lowered and the catalytic activity cannot be exhibited.

  Since the density of the electrode 10 is within the above range, the electrode 10 has a large number of fine flow paths 13 (passage holes) having different opening areas (opening diameters) and a large number of fine front and rear surfaces having different opening areas (opening diameters). The electrode 10 is formed into a porous material having the flow ports 14 of 11 and 12, and can increase the specific surface area of the electrode 10. While the gas or liquid flows through the flow passages 13 (passage holes), the electrode 10 can pass the gas or liquid. It is possible to make wide contact with the contact surfaces of those flow paths 13. Further, the catalytic action of the electrode 10 is improved, and the electrode 10 can exhibit excellent catalytic activity.

  Fine powder of Pt (Pt processed into powder), Fine powder of Pb (Pb processed into powder), Fine powder of Rh (Rh processed into powder), Fine powder of Ru (in powder form) Processed Ru), Ir fine powder (Ir processed into powder), Os fine powder (Os processed into powder), Ti fine powder (Ti processed into powder), Cr Fine powder (Cr processed into powder), Mn fine powder (Mn processed into powder), Fe fine powder (Fe processed into powder), Co fine powder (processed into powder) Co), fine Ni powder (Ni processed into powder), Cu fine powder (Cu processed into powder), Zn fine powder (Zn processed into powder), Nb fine powder The particle size of (powder-processed Nb), Mo fine powder (powder-processed Mo), and Ag fine powder (powder-processed Ag) is 10 μm to 2 It is in the range of 0μm.

  When the particle size of the fine particles of the platinum group metal 41 or the particle size of the fine particles of the transition metal 42 is less than 10 μm, the fine particles of these metals block the flow paths 13 (passage holes), and a large number of electrodes 10 are formed. The fine flow path 13 cannot be formed, the specific surface area of the electrode 10 cannot be increased, and the catalytic action of the electrode 10 decreases, so that the catalytic activity cannot be exhibited. When the particle size of the fine particles of the platinum group metal 41 or the particle size of the fine particles of the transition metal 42 exceeds 200 μm, the opening area (opening diameter) of the flow path 13 (passage hole) and the passage of the front and rear surfaces 11, 12 are obtained. The opening area (opening diameter) of the flow opening 15 becomes larger than necessary, a large number of minute flow paths 13 cannot be formed in the electrode 10, the specific surface area of the electrode 10 cannot be increased, and the electrode 10 However, the catalytic activity of is reduced and the catalytic activity cannot be exhibited.

  In the electrode 10, since the particle size of the fine powder of the platinum group metal 41 and the particle size of the fine powder of the transition metal 42 are within the above range, the electrode 10 has a large number of fine flow paths having different opening areas (opening diameters). 13 (passage hole) and a large number of minute front and rear surfaces 11 and 12 having different opening areas (opening diameters) through which the flow ports 14 are formed, and the specific surface area of the electrode 10 can be increased. While the gas or liquid flows through the passage 13, the gas or liquid can be widely brought into contact with the contact surfaces of the electrodes 10 in the passages 13. Further, the catalytic action of the electrode 10 is improved, and the electrode 10 can exhibit excellent catalytic activity.

  As a specific example of the platinum group metal or the transition metal used for the electrode 10, as shown in FIG. 10, a powdered Pt43 (platinum) fine powder 47 (particle size: 10 μm to 200 μm) and powdered Ni44 (nickel) fine powder 48 (particle size: 10 μm to 200 μm) processed into powder, and Fe45 (iron) fine powder 49 (particle size: 10 μm to 200 μm) processed into powder, and powder processed The Cu 46 (copper) fine powder 50 (particle size: 10 μm to 200 μm) is used as a raw material. The electrode 10 is formed by compressing a metal fine powder mixture 51, which is a uniform mixture and dispersion of fine powders 47 to 50 of Pt43, Ni44, Fe45, and Cu46, into a thin plate having a predetermined area to form a metal fine powder compressed product 52. By firing the fine powder compact 52 at a predetermined temperature, it is formed into a thin plate shape having a porous structure in which a large number of fine flow paths 13 (passage holes) are formed.

  In the electrode 10, the total weight of the fine metal powder mixture 51 of the fine powder 47 of Pt43 is set so that the combined work function of the work function of Ni44, the work function of Fe45, and the work function of Cu46 approximates the work function of the platinum group element. To the total weight of the metal fine powder mixture 51 of the fine powder 48 of Ni44, the weight ratio of the fine powder 49 of Fe45 to the total weight of the metal fine powder mixture 51, and the metal fine powder mixture of the fine powder 50 of Cu46. The weight ratio of 51 to the total weight has been determined. The fine powder 50 of Cu46 has a lower melting point than that of the fine powder 47 of Pt43, the fine powder 48 of Ni44, and the fine powder 49 of Fe45, and the fine powder 47 of Pt43, the fine powder 48 of Ni44, and the fine powder of Fe46. It serves as a binder (bonding component) for bonding the body 49. In the electrode 10, the fine powder 50 of Cu46 having the highest melting point is melted during the firing of the metal fine powder compact 52 compressed into a thin plate having a predetermined area, and the fine Cu powder 46 is used as a binder to form the fine powder 47 of Pt43 and the fine powder 48 of Ni44. And a fine powder 49 of Fe45 are joined.

  The weight ratio of the fine powder 47 of Pt43 (platinum group metal 41) to the total weight (100%) of the fine metal powder mixture 51 is in the range of 5 to 10%, preferably in the range of 5 to 6%. The weight ratio of the fine powder of Ni44 (transition metal 42) to the total weight (100%) of the body mixture 51 is in the range of 30% to 45%, preferably 40% to 45%. The weight ratio of the fine powder 49 of Fe45 (transition metal 42) to the total weight (100%) of the fine metal powder mixture 51 is in the range of 30 to 45%, preferably 40% to 45%. The weight ratio of the fine powder 50 of Cu46 (transition metal 42) to the total weight of 51 (100%) is in the range of 3% to 5%, preferably 4%. When the weight ratio of the fine powder 47 of Pt43, the weight ratio of the fine powder 48 of Ni44, the weight ratio of the fine powder 49 of Fe45, and the weight ratio of the fine powder 50 of Cu46 are out of the above ranges, the fine powders 48 to 50 The composite work function cannot be approximated to the work function of the platinum group element, and the electrode 10 made by firing the metal fine powder compact 52 obtained by compressing the metal fine powder mixture 51 is an electrode supporting the platinum group element. It is not possible to exhibit substantially the same catalytic activity (catalytic action).

  FIG. 4 is an exploded perspective view showing an example of the cell 16 using the electrode 10, and FIG. 5 is a side view of the cell 16 using the electrode 10. FIG. 6 is a diagram for explaining the power generation of the polymer electrolyte fuel cell 17 using the electrode 10, and FIG. 7 is a diagram showing the result of the electromotive voltage test of the electrode 10. FIG. 8 is a diagram showing a result of the IV characteristic test of the electrode 10.

  As an example of the cell 16 using the electrode 10, as shown in FIG. 4, a fuel electrode 18 (anode) using the electrode 10, an air electrode 19 (cathode) using the electrode 10, a fuel electrode 18 and an air A solid polymer electrolyte membrane 20 (electrode assembly membrane) (fluorine-based ion exchange membrane) interposed in the electrode 19, a separator 21 (bipolar plate) located outside the fuel electrode 18 in the thickness direction, and a thickness direction of the air electrode 19 It is formed of a separator 22 (bipolar plate) located outside. A supply channel for a reaction gas (hydrogen, oxygen, etc.) is engraved (engraved) on the separators 21 and 22.

  In the cell 16, as shown in FIG. 5, the fuel electrode 18, the air electrode 19, and the solid polymer electrolyte membrane 20 are overlapped and integrated in the thickness direction to form a membrane / electrode assembly 23 (Membrane Electrode Assembly, MEA). The membrane / electrode assembly 23 is sandwiched by the separators 21 and 22. In the membrane / electrode assembly 23, the surface of the fuel electrode 18 adheres to one surface of the solid polymer electrolyte membrane 20 and the surface of the air electrode 19 adheres to one surface of the solid polymer electrolyte membrane 20 by hot pressing. ing. In the polymer electrolyte fuel cell 17, a plurality of cells 16 (single cells) are overlapped in one direction and connected in series to form a cell stack (fuel cell stack). The solid polymer electrolyte membrane 20 has proton conductivity and no electron conductivity.

  A gas diffusion layer 24 is formed between the fuel electrode 18 and the separator 21, and a gas diffusion layer 25 is formed between the air electrode 19 and the separator 22. Gas seals 26 are installed between the fuel electrode 18 and the separator 21 and above and below the gas diffusion layer 24. Gas seals 27 are installed between the air electrode 19 and the separator 22 and above and below the gas diffusion layer 25.

In the polymer electrolyte fuel cell 17, as shown in FIG. 6, hydrogen (fuel) is supplied to the fuel electrode 18 (electrode 10) and air (oxygen) is supplied to the air electrode 19 (electrode 10). At the fuel electrode 18 (electrode 10), hydrogen is decomposed into protons (hydrogen ions, H ⁺ ) and electrons by the reaction (catalytic action) of H ₂ → 2H ⁺ + 2e ⁻ . After that, protons move to the air electrode 19 (electrode 10) through the solid polymer electrolyte membrane 20, and electrons move to the air electrode 19 through the lead wire 28. Protons generated at the fuel electrode 18 flow through the solid polymer electrolyte membrane 20. At the air electrode 19, the protons that have moved from the solid polymer electrolyte membrane 20 and the electrons that have moved through the conductor 28 react with oxygen in the air, and water is produced by the reaction of 4H ⁺ + O ₂ + 4e → 2H ₂ O.

  In the electrode 10, at least three kinds of transition metals 42 are selected from the transition metals 42 so that the composite work function of the work functions of the transition metals 42 approximates the work function of the platinum group element, and the selected transition metals 42 are selected. The weight ratio of the platinum group metal 41 to the total weight of the fine metal powder mixture 51 of the platinum group metal 41 is determined so that the combined work function of Since the weight ratio of the mixture 51 to the total weight is determined, the electrode 10 has substantially the same work function as the electrode supporting the platinum group element, and the same catalytic activity (catalyst action) as the electrode supporting the platinum group element. ), Hydrogen is efficiently decomposed into protons and electrons.

  For the fuel electrode 18 (electrode 10) and the air electrode 19 (electrode 10) shown as specific examples, Ni44, Fe45, and Cu46 are selected so that the composite work function of the work functions approximates the work function of the platinum group element. The weight ratio of Pt43 to the total weight of the fine metal powder mixture 51 is determined so that the total work function of the selected Ni44, Fe45, and Cu46 is close to the work function of the platinum group element. Since the weight ratio of the fine powder 48 of Ni44, the fine powder 49 of Fe45, and the fine powder 50 of Cu46 with respect to the total weight of the mixture 51 is determined, the fuel electrode 18 (electrode 10) and the air electrode. 19 (electrode 10) has substantially the same work function as the electrode supporting the platinum group element and exhibits substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, and hydrogen and protons Efficiency is often broken down into door.

  In the electromotive voltage test, the voltage (V) between the fuel electrode 18 (electrode 10) and the air electrode 19 (electrode 10) was measured for 15 minutes after hydrogen gas was injected. In the diagram showing the results of the electromotive force test in FIG. 7, the horizontal axis represents the measurement time (min), and the vertical axis represents the voltage (V) between the fuel electrode 18 (electrode 10) and the air electrode 19 (electrode 10). Represents In the polymer electrolyte fuel cell 17 using the electrode 10, the voltage between the electrodes was 1.05 (V) to 1.079 (V) as shown in FIG. 7.

  In the IV characteristic test, a load 29 was connected between the fuel electrode 18 (electrode 10) and the air electrode 19 (electrode 10), and the relationship between voltage and current was measured. In the diagram showing the results of the IV characteristic test in FIG. 8, the horizontal axis represents current (A) and the vertical axis represents voltage (V). In the polymer electrolyte fuel cell 17 using the electrode 10, a gradual voltage drop was observed as shown in FIG. As shown in the results of the electromotive voltage test of FIG. 7 and the results of the IV characteristic test of FIG. 8, the electrode 10 has an excellent catalytic action for promoting the reaction of releasing electrons to become hydrogen ions, and it is excellent. It was confirmed to have an oxygen reduction function (catalytic action).

  In the electrode 10, at least three kinds of transition metals 42 are selected from the transition metals 42 so that the composite work function of the work functions of the transition metals 42 approximates the work function of the platinum group element, and the selected transition metals 42 are selected. The weight ratio of the platinum group metal 41 to the total weight of the metal fine powder mixture 51 is determined so that the combined work function of the above-mentioned work functions approximates the work function of the platinum group element, and Since the weight ratio of the metal fine powder mixture 51 to the total weight is determined, the electrode 10 has substantially the same work function as the electrode supporting the platinum group element, and the same catalytic activity as the electrode supporting the platinum group element. A fuel electrode 18 (anode) or an air electrode 19 (cathode) capable of exerting (catalytic action), sufficiently and reliably utilizing its catalytic function, and having excellent catalytic activity (catalytic action). When It can be suitably used Te.

  Further, in the electrode 10 made of Ni44, Fe45 and Cu46 as the transition metal 42, Ni44, Fe45 and Cu46 are selected and selected so that the composite work function of the work functions approximates the work function of the platinum group element. The weight ratio of the fine powder 47 of Pt43 to the total weight of the fine metal powder mixture 51 is determined so that the total work function of the work functions of Ni44, Fe45, and Cu46 approximated to the work function of the platinum group element is Since the weight ratio of the fine powder 48 of Ni44, the fine powder 49 of Fe45 and the fine powder 50 of Cu46 to the total weight of the fine powder mixture 51 is determined, the electrode 10 carries the platinum group element. The electrode has a work function almost the same as that of the electrode, and can exhibit the same catalytic activity (catalytic action) as the electrode supporting the platinum group element. Can be suitably used as a fuel electrode 18 (anode) and an air electrode 19 with a can be reliably utilized excellent catalytic activity (catalytic) (cathode).

  Since the electrode 10 exhibits substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, the use of the electrode 10 in the polymer electrolyte fuel cell 17 is sufficient for the fuel cell 17. Electricity can be generated and sufficient electric energy can be supplied to the load 29 connected to the fuel cell 17. The electrode 10 contains inexpensive transition metals (eg, Ni44, Fe45, Cu46) selected from various transition metals, and the weight ratio of the fine particles of the transition metal 42 to the total weight of the fine metal powder mixture 51 ( The weight ratio of the fine powder 48 of Ni44, the weight ratio of the fine powder 49 of Fe45, the weight ratio of the fine powder 50 of Cu46) is within the above range, and the ratio of the fine powder of the platinum group metal 41 to the total weight of the fine metal powder mixture 51 is Since the weight ratio (the weight ratio of the fine powder 47 of Pt43) is in the above range and the content of the expensive platinum group metal 41 is small, the fuel electrode 19 (anode) and the air electrode 18 (cathode) can be manufactured at low cost. it can.

  FIG. 9 is a diagram for explaining electrolysis of the hydrogen gas generator 30 using the electrode 10. As an example of the hydrogen gas generator 30 using the electrode 10, as shown in FIG. 9, an anode 31 (anode) using the electrode 10, a cathode 32 (cathode) using the electrode 10, an anode 31 and a cathode A solid polymer electrolyte membrane 33 (electrode assembly membrane) (fluorine-based ion exchange membrane) interposed between 32, an anode power feeding member 34 and a cathode power feeding member 35, an anode water storage tank 36 and a cathode water storage tank 37. , An anode main electrode 38 and a cathode main electrode 39.

  In the hydrogen gas generator 30, the anode 31 (anode), the cathode 32 (cathode), and the solid polymer electrolyte membrane 33 are overlapped and integrated in the thickness direction to form a membrane / electrode assembly 40 (Membrane Electrode Assembly, MEA). The membrane / electrode assembly 40 is sandwiched between the anode power feeding member 34 and the cathode power feeding member 35. The solid polymer electrolyte membrane 33 has proton conductivity and no electron conductivity. In the membrane / electrode assembly 40, the surface of the cathode 32 (cathode) is brought into close contact with one surface of the solid polymer electrolyte membrane 33 by hot pressing, and the anode 31 (anode) is bonded to one surface of the solid polymer electrolyte membrane 20. The surfaces are in close contact.

  The anode power supply member 34 is located outside the anode 31 (anode) and is in close contact with the anode 31, and supplies a positive current to the anode 31. The anode water storage tank 36 is located outside the anode power supply member 34 and is in close contact with the anode power supply member 34. The anode main electrode 38 is located outside the anode water storage tank 36 and supplies a positive current to the anode power supply member 34. The cathode power supply member 35 is located outside the cathode 32 (cathode), is in close contact with the cathode 32, and supplies a negative current to the cathode 32. The cathode water storage tank 37 is located outside the cathode power supply member 35 and is in close contact with the cathode power supply member 35. The cathode main electrode 239 is located outside the cathode water storage tank 37 and supplies a negative current to the cathode power supply member 35.

In the hydrogen gas generator 30, as shown by the arrow in FIG. 9, water (H ₂ O) is supplied to the anode water storage tank 36 and the cathode water storage tank 37, and a positive current is supplied from the power supply to the anode main electrode 38. At the same time, a negative current is supplied from the power supply to the cathode main electrode 39. The positive current supplied to the anode main electrode 38 is supplied from the anode power supply member 34 to the anode 31 (anode), and the negative current supplied to the cathode main electrode 39 is supplied from the cathode power supply member 35 to the cathode 32 (cathode). To be done.

In the anode 31 (anode) (electrode 10), oxygen is generated by the anodic reaction (catalysis) of 2H ₂ O → 4H ⁺ + 4e ⁻ + O ₂ , and in the cathode 32 (cathode) (electrode 10), 4H ⁺ + 4e ⁻ → Oxygen is produced by the cathodic reaction (catalysis) of 2H ₂ . Protons (hydrogen ions: H ⁺ ) move to the cathode 32 through the solid polymer electrolyte membrane 33. Protons generated at the anode 31 flow through the solid polymer electrolyte membrane 33.

  For the electrode 10 (anode 31 and cathode 32), at least three kinds of transition metals 42 are selected from the transition metals 42 so that the composite work function of the work functions of the transition metals 42 approximates the work function of the platinum group element. The weight ratio of the fine powder 47 of the platinum group metal 41 to the total weight of the fine metal powder mixture 51 is determined so that the composite work function of the work functions of the selected transition metals 42 approximates the work function of the platinum group element. Since the weight ratio of the selected transition metal 42 to the total weight of the fine metal powder mixture 51 is determined, the electrode 10 (anode 31 and cathode 32) has substantially the same work function as the electrode carrying the platinum group element. In addition, it is possible to exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, and it is possible to utilize its catalytic function sufficiently and reliably, which is excellent. It can be suitably used as an anode 31 (anode) and a cathode 32 having a medium activity (catalytic) (cathode).

  Further, the electrode 10 (anode 31 and cathode 32) using Ni44, Fe45, and Cu46 as the transition metals 42 as raw materials is composed of Ni44 and Fe45 so that the combined work function of the work functions approximates the work function of the platinum group element. Cu46 and Pt43 fine powder 47 with respect to the total weight of the metal fine powder mixture 51 is selected so that the total work function of the selected Ni44, Fe45 and Cu46 approximates the work function of the platinum group element. The weight ratio is determined, and the weight ratio of the fine powder of Ni44, the weight ratio of the fine powder 49 of Fe45, and the weight ratio of the fine powder of Cu46 to the total weight of the metal fine powder mixture 51 is determined. 10 (anode 31 and cathode 32) has substantially the same work function as the electrode supporting the platinum group element, and is substantially the same as the electrode supporting the platinum group element. An anode 31 (anode) and a cathode 32 (cathode) that can exhibit catalytic activity (catalyst action), can fully and surely utilize the catalytic function, and have excellent catalytic activity (catalyst action). Can be preferably used as.

  Since the electrode 10 (anode 31 and cathode 32) exhibits substantially the same catalytic activity (catalytic action) as the electrode carrying the platinum group element, the electrode 10 (anode 31 and cathode 32) is connected to the hydrogen gas generator 30. The electrolysis can be efficiently performed in the hydrogen gas generation device 30 by using the hydrogen gas generation device, and a large amount of hydrogen gas can be generated in a short time. The electrode 10 (anode 31 and cathode 32) contains inexpensive transition metals (Ni44, Fe45, Cu46) selected from various transition metals, and fine particles of the transition metals 42 based on the total weight of the metal fine powder mixture 51. The weight ratio of the body (the weight ratio of the fine powder 48 of Ni44, the weight ratio of the fine powder 49 of Fe45, the weight ratio of the fine powder 50 of Cu46) is within the above range, and the platinum group metal relative to the total weight of the metal fine powder mixture 51. Since the weight ratio of the fine powder of 41 (the weight ratio of the fine powder 47 of Pt43) is within the above range and the content of the expensive platinum group metal 41 is small, the anode 31 (anode) and the cathode 32 (cathode) can be made inexpensive. Can be made.

  FIG. 10 is a diagram illustrating a method of manufacturing the electrode 10. As shown in FIG. 10, the electrode 10 (fuel electrode 18 and air electrode 19, anode 31 and cathode 32) has a transition metal selection step S1, a fine metal powder preparation step S2, a fine powder weight ratio determination step S3, and a fine metal powder. It is manufactured by an electrode manufacturing method including a mixture preparation step S4, a fine metal powder compact preparation step S5, and a thin plate electrode preparation step S6. In the electrode manufacturing method, the electrode 10 (fuel electrode 18 and air electrode 19, anode 31 and cathode 32) is manufactured using the platinum group metal 41 and at least three kinds of transition metals 42 as raw materials.

  In the transition metal selection step S1, at least one platinum group metal 41 (platinum (Pt), palladium (Pb), rhodium (Rh), ruthenium (Ru), iridium (Ir), among the various platinum group metals 41, Osmium (Os) is selected and selected from various transition metals 42. At least three kinds of transition metals 42 are selected so that the composite work function of the work functions approximates the work function of the platinum group element. At least three types of transition metals 42 (Ti (titanium), Cr (chrome), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Nb (niobium), Mo (molybdenum), Ag (silver)) is selected. Note that Pt43 (platinum) is selected as the platinum group metal 41 used for the electrode 10, and Ni44 (nickel), Fe45 (iron), and Cu46 (copper) are selected as the transition metal 42 used for the electrode 10. .

  In the metal fine powder preparation step S2, platinum 43 (Pt) is finely pulverized by a fine pulverizer to a particle size of 10 μm to 200 μm to produce Pt43 fine powder 47 having a particle size of 10 μm to 200 μm, and Ni44 ( Nickel) is finely pulverized to a particle size of 10 μm to 200 μm to form a fine powder 48 of Ni44 having a particle size of 10 μm to 200 μm, and Fe45 (iron) is finely ground to a particle size of 10 μm to 200 μm by a fine pulverizer. A fine powder 49 of Fe45 having a particle diameter of 10 μm to 200 μm is produced, and Cu46 (copper) is finely pulverized to a particle diameter of 10 μm to 200 μm by a fine pulverizer to produce a fine powder 50 of Cu46 having a particle diameter of 10 μm to 200 μm.

  The electrode manufacturing method is to finely pulverize Pt43 (platinum group metal 41), Ni44 (transition metal 42), Fe45 (transition metal 42), and Cu46 (transition metal 42) to a particle size of 10 μm to 200 μm to obtain a large number of fine particles. It is possible to form a thin plate-shaped electrode 10 having a porous structure having a large specific surface area by being formed into a porous material having various flow passages 13 (passage holes). It is possible to make the electrode 10 capable of widely contacting the liquid or the liquid with the contact surfaces of the flow paths 13 of the electrode 10.

  In the fine powder weight ratio determination step S3, the combined work function of the work powders of the fine powder 48 of Ni44, the fine powder 49 of Fe45, and the fine powder 50 of Cu46 produced in the fine metal powder producing step S2 is the work of the platinum group element. The weight ratio of the Pt43 fine powder 47 to the total weight of the metal fine powder mixture 51 is determined so as to approximate the function, and the weight ratio of the Ni44 fine powder 48 to the total weight of the metal fine powder mixture 51 is determined. The weight ratio of the Fe45 fine powder 49 to the total weight of the fine powder mixture 51 is determined, and the weight ratio of the Cu46 fine powder 50 to the total weight of the metal fine powder mixture 51 is determined.

  In the fine powder weight ratio determining step S3, the weight ratio of the fine powder 47 of Pt43 (platinum group metal 41) to the total weight (100%) of the metal fine powder mixture 51 is in the range of 5 to 10%, preferably 5 to 6%. Determine in the range of%. In the fine powder weight ratio determining step S3, the weight ratio of the fine powder 48 of Ni44 (transition metal 42) to the total weight (100%) of the metal fine powder mixture 51 is in the range of 30% to 45%, preferably 40%. Determined in the range of 45%, the weight ratio of the fine powder 49 of Fe45 (transition metal 42) to the total weight (100%) of the metal fine powder mixture 51 is in the range of 30% to 45%, preferably 40% to 45%. %, And the weight ratio of the fine powder 50 of Cu46 (transition metal 42) to the total weight of the fine metal powder mixture 51 (100%) is in the range of 3% to 5%, preferably 4%. decide.

  The electrode manufacturing method selects Ni44 (nickel), Fe45 (iron), and Cu46 (copper) of the transition metal 42 so that the synthetic work function is close to the work function of the platinum group element, and the synthetic work function is the platinum group. The weight ratio of the fine powder 47 of Pt43, the fine powder 48 of Ni44, the weight ratio of the fine powder 49 of Fe45, and the fine powder of Cu46 to the total weight of the fine metal powder mixture 51 so as to approximate the work function of the element. By determining the weight ratio of 50 within the above range, the composite work function of the work functions of the fine powder 48 of Ni44, the fine powder 49 of Fe45, and the fine powder 50 of Cu46 can be approximated to the work function of the platinum group element. In spite of the small content of the platinum group metal 41 (Pt43), it has a work function substantially the same as that of the electrode supporting the platinum group element, and is substantially the same as the electrode supporting the platinum group element. 10 containing a small amount of platinum group metal (fuel) capable of exhibiting similar catalytic activity (catalytic action) and having excellent catalytic activity (catalytic action) and being able to utilize the catalytic function sufficiently and reliably. The pole 18 and the cathode 19, the anode 31 and the cathode 32) can be made.

  The electrode manufacturing method is as follows: the weight ratio of the fine powder 48 of Ni44 (transition metal 42), the weight ratio of the fine powder 49 of Fe45 (transition metal 42), and the fine powder of Cu46 (transition metal 42) with respect to the total weight of the fine metal powder mixture 51. Since the total weight of the body 50 is in the above range and the weight ratio of the fine powder 47 of Pt43 (platinum group metal 41) to the total weight of the fine metal powder mixture 51 is in the above range, the content of the expensive platinum group metal 41 is high. Therefore, the electrode 10 (fuel electrode 18 and air electrode 19, anode 31 and cathode 32) can be manufactured at low cost.

  In the metal fine powder mixture preparing step S4, the fine powder 47 of Pt43 having the weight ratio determined in the fine powder weight ratio determining step S3 and the fine powder 48 of Ni44 and the fine powder weight having the weight ratio determined in the fine powder weight ratio determining step S3. The fine powder 49 of Fe45 having the weight ratio determined by the ratio determining step S3 and the fine powder 50 of Cu46 having the weight ratio determined by the weight ratio determining step S3 are put into a mixer, and the fine powder 47 of Pt43 47 is mixed by the mixer. , Ni44 fine powder 48, Fe45 fine powder 49, and Cu46 fine powder 50 are agitated and mixed to uniformly obtain Pt43 fine powder 47, Ni44 fine powder 48, Fe45 fine powder 49, and Cu46 fine powder 50. A mixed and dispersed metal fine powder mixture 51 is prepared.

  In the metal fine powder compressed material producing step S5, the metal fine powder mixture 51 produced in the metal fine powder mixture producing step S4 is pressurized with a predetermined pressure to compress the metal fine powder mixture 51 into a thin plate having a predetermined area. Make a compact 52. In the metal fine powder compressed material producing step S5, a thin plate-shaped metal fine powder compressed material 52 is produced by pressing the metal fine powder mixture 51 into a mold and pressing the mold with a press machine.

  The press pressure (pressure) during the press working is in the range of 500 Mpa to 800 Mpa. When the pressing pressure (pressure) is less than 500 MPa, the opening area (opening diameter) of the flow path 13 (passage hole) formed in the metal fine powder compact 52 (thin plate electrode) becomes large, and the thickness of the metal fine powder compact 52 is increased. While the dimension L1 is set to 0.03 mm to 0.8 mm (preferably 0.05 mm to 0.5 mm), a large number of fine flow paths 13 (passage holes) having an opening diameter in the range of 1 μm to 100 μm are compressed with metal fine powder. It cannot be formed on the object 52 (thin plate electrode).

  If the pressing pressure (pressure) exceeds 800 MPa, the opening area (opening diameter) of the flow path 13 (passage hole) formed in the metal fine powder compact 52 (thin plate electrode) becomes smaller than necessary, and the metal fine powder compression While the thickness dimension L1 of the object 52 is 0.03 mm to 0.8 mm (preferably 0.05 mm to 0.5 mm), a large number of fine flow paths 13 (passage holes) having an opening diameter in the range of 1 μm to 100 μm are formed. It cannot be formed on the metal fine powder compact 52 (thin plate electrode).

  In the electrode manufacturing method, the metal fine powder mixture 51 is pressed (compressed) at a pressure within the above range, and the thickness dimension L1 of the metal fine powder compressed material 52 (thin plate electrode) is 0.03 mm to 0.8 mm (preferably , 0.05 mm to 0.5 mm) and a large number of fine flow paths 13 (passage holes) having an opening diameter in the range of 1 μm to 100 μm are formed. In the electrode manufacturing method, since the electrode 10 having the thickness dimension L1 in the range of 0.03 mm to 0.8 mm (preferably in the range of 0.05 mm to 0.5 mm) can be manufactured, the electric resistance can be reduced. The electrode 10 (the fuel electrode 18 and the air electrode 19, the anode 31 and the cathode 32) capable of passing the current smoothly can be formed.

  In the thin plate electrode producing step S6, the metal fine powder compact 52 produced in the metal fine powder compact producing step S5 is put into a firing furnace (combustion furnace, electric furnace, etc.), and the metal fine powder compact 52 is placed in the firing oven. By firing (sintering) at a predetermined temperature, a thin plate-like structure (fuel electrode 18 and air electrode 19, anode 31 and cathode 32) in which a large number of fine flow paths 13 (passage holes) are formed is produced.

  In the thin plate electrode forming step S6, the metal fine powder compact 52 is fired for a long time at a temperature (for example, 1100 ° C to 1400 ° C) for melting the fine powder 50 of Cu46 (melting point: 1084.5 ° C) having the lowest melting point. The firing (sintering) time is 3 hours to 6 hours. In the thin plate electrode forming step S5, the fine powder 50 of Cu46 having the lowest melting point is melted at the time of firing the fine metal powder compact 52 compressed into a thin plate having a predetermined area, and the fine powder 50 of Cu46 is used as a binder for Pt43. The fine powder 47, the fine powder 48 of Ni44, and the fine powder 49 of Fe45 are joined (fixed). The melting point of Pt43 is 1774 ° C, the melting point of Ni44 is 1455 ° C, and the melting point of Fe45 is 1539 ° C. In the thin plate electrode forming step S6, the metal fine powder compact 52 is fired at a predetermined temperature to form a thin plate-shaped electrode 10 (a fuel electrode 18 and a porous plate) in which a large number of fine flow paths 13 (passage holes) are formed. The air electrode 19, the anode 31 and the cathode 32) are manufactured.

  In the electrode manufacturing method, the fine powder 50 of Cu46 having the lowest melting point is used as a binder to bond the fine powder 47 of Pt43, the fine powder 48 of Ni44, and the fine powder 49 of Fe45 to each other so that a large number of fine flow paths 13 (passages) can be formed. It is possible to form a thin plate-shaped electrode 10 (fuel electrode 18 and air electrode 19, anode 31 and cathode 32) having a porous structure, and to maintain the shape with high strength and to prevent impact. The non-platinum electrode 10 (the fuel electrode 18 and the air electrode 19, the anode 31 and the cathode 32) capable of preventing breakage and damage when added can be manufactured.

  The electrode manufacturing method uses at least 3 kinds of transition metals 42 so that the composite work function of the work functions of at least 3 kinds of transition metals 42 selected from various kinds of transition metals 42 approximates the work function of the platinum group element. A transition metal selection step S1 for selecting a type of transition metal 42 (for example, Ni44, Fe45, Cu46), and pulverizing the platinum group metal 41 (Pt43) to produce a platinum group metal fine powder (fine powder 47 of Pt43). A fine metal powder for producing a fine transition metal powder (fine powder 48 of Ni44, fine powder 49 of Fe45, fine powder 50 of Cu46) by finely pulverizing at least three kinds of transition metals 42 selected in the transition metal selection step S1. The composite work function of the production process S2 and the work function of at least three kinds of transition metal fine powders produced by the metal fine powder production process S2 is the work function of the platinum group element. To the weight ratio of the platinum group metal fine powder (Pt43 fine powder 47) and at least three kinds of transition metal fine powders (Ni44 fine powder 48, Fe45 fine powder 49, Cu46 fine powder 50). Fine powder weight ratio determining step S3 for determining the weight ratio, and fine metal powder obtained by mixing and dispersing the platinum group metal fine powder and the at least three kinds of transition metal fine powder in the weight ratio determined in the fine powder weight ratio determining step S3. Metal fine powder mixture producing step S4 for producing the body mixture 51, and metal fine powder compressed article 52 for producing the metal fine powder compressed article 52 by pressurizing the metal fine powder mixture 51 produced by the metal fine powder mixture producing step S4 with a predetermined pressure. A thin plate having a porous structure in which a large number of fine channels 13 are formed by firing the metal fine powder compressed material 52 produced in the production step S5 and the metal fine powder compressed material production step S5 at a predetermined temperature. The thickness dimension L1 is in the range of 0.03 mm to 0.8 mm (preferably, in the range of 0.03 mm to 0.5 mm) by the steps of the porous structure thin plate electrode forming step S6 for forming the electrode 10 formed in FIG. It is possible to manufacture the electrode 10 in which a large number of fine flow paths 13 (passage holes) are formed, the electrode 10 can be manufactured at low cost, and also the catalyst 10 has an excellent catalytic activity (catalytic action). The electrode 10 (fuel electrode 18 and air electrode 19, the anode 31 and the cathode 32) containing a small amount of platinum group metal that can be used sufficiently and reliably can be manufactured.

  In the electrode manufacturing method, since the electrode 10 produced thereby exhibits substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group element, the polymer electrolyte fuel cell 17 should generate sufficient electricity. And a non-platinum electrode 10 (fuel electrode 18 and air electrode 19, anode 31 and cathode 32) capable of supplying sufficient electric energy to the load 29 connected to the polymer electrolyte fuel cell 17. Can be made. The electrode manufacturing method includes a non-platinum electrode 10 (a fuel electrode 18 and an air electrode 19) that can efficiently perform electrolysis in the hydrogen gas generator 30 and can generate a large amount of hydrogen gas in a short time. , Anode 31 and cathode 32) can be made.

10 electrode 11 front surface 12 rear surface 13 flow path (passage hole)
14 flow port 15 outer peripheral edge 16 cell 17 polymer electrolyte fuel cell 18 fuel electrode (anode)
19 Air electrode (cathode)
20 solid polymer electrolyte membrane 21 separator (bipolar plate)
22 Separator (bipolar plate)
23 Membrane / electrode assembly 24 Gas diffusion layer 25 Gas diffusion layer 26 Gas seal 27 Gas seal 28 Conductive wire 29 Load 30 Hydrogen gas generator 31 Anode (anode)
32 cathode (cathode)
33 Solid Polymer Electrolyte Membrane 34 Anode Power Feeding Member 35 Cathode Power Feeding Member 36 Anode Water Tank 37 Cathode Water Tank 38 Anode Main Electrode 39 Cathode Main Electrode 40 Membrane / Electrode Assembly 41 Platinum Group Metal 42 Transition Metal 43 Pt (Platinum)
44 Ni (nickel)
45 Fe (iron)
46 Cu (copper)
47 Pt (platinum) fine powder 48 Ni (nickel) fine powder 49 Fe (iron) fine powder 50 Cu (copper) fine powder 51 Metal fine powder mixture 52 Metal fine powder compressed product L1 Thickness dimension S1 Transition metal selection Step S2 Metal fine powder preparation step S3 Fine powder weight ratio determination step S4 Metal fine powder mixture preparation step S5 Metal fine powder compressed material preparation step S6 Thin plate electrode preparation step

Claims (14)

In the electrode used as an anode or a cathode,
The electrode is formed from at least one platinum group metal selected from various platinum group metals and at least three transition metals selected from various transition metals, and the selected at least one platinum group A metal fine powder mixture obtained by uniformly mixing and dispersing a platinum group metal fine powder obtained by finely pulverizing a group metal and a transition metal fine powder obtained by finely pulverizing at least three selected transition metals is compressed into a thin plate having a predetermined area. An electrode characterized by being formed into a thin plate having a porous structure in which a large number of fine flow paths are formed by baking after that.   In the electrode, at least three kinds of transition metals are selected from the various kinds of transition metals so that the composite work function of the work functions of the selected at least three kinds of transition metals approximates the work function of the platinum group element. The electrode according to claim 1, which is provided.   The electrode according to claim 1 or 2, wherein a thickness dimension of the electrode is in a range of 0.03 mm to 0.8 mm.   The transition metals are Ni (nickel), Fe (iron), and Cu (copper) having the lowest melting point, and the electrode has a work function of Ni, a work function of Fe, and a work function of Cu. The weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture and the total work weight of the Fe fine powder to the total weight of the metal fine powder mixture so that the synthetic work function approximates the work function of the platinum group element. The electrode according to any one of claims 1 to 3, wherein a weight ratio and a weight ratio of the Cu fine powder to the total weight of the metal fine powder mixture are defined.   The weight ratio of the platinum group metal fine powder to the total weight of the metal fine powder mixture is in the range of 5 to 10%, and the weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture is 30% to 45% range, the weight ratio of the Fe fine powder to the total weight of the metal fine powder mixture is 30% to 45%, the weight ratio of the Cu fine powder to the total weight of the metal fine powder mixture is The electrode according to claim 4, which is in the range of 3% to 5%.   The electrode according to any one of claims 1 to 5, wherein the porosity of the thin plate-shaped electrode having the porous structure is in the range of 15% to 30%. The density of the thin plate shaped electrodes of porous ^structure, the electrode according to any claims 1 to 6 in the range of ^{5.0g / cm 2 ~7.0g / cm 2} .   The electrode according to any one of claims 1 to 7, wherein the particle size of the platinum group metal fine powder and the particle size of the transition metal fine powder are in the range of 10 µm to 200 µm.   In the electrode, the fine powder of Cu having the highest melting point is melted during firing of the fine metal powder mixture compressed into a thin plate having a predetermined area, and the fine powder of the platinum group metal and the fine powder of Ni are used with the molten Cu as a binder. The electrode according to any one of claims 4 to 8, wherein the electrode and the fine powder of Fe are bonded together. In an electrode manufacturing method for manufacturing an electrode used as an anode or a cathode,
In the electrode manufacturing method, at least one platinum group metal is selected from various platinum group metals, and a composite work function of work functions of at least three transition metals selected from various transition metals is a platinum group element. A transition metal selection step of selecting at least three kinds of transition metals from the various transition metals so as to approximate the work function, and finely pulverizing at least one kind of platinum group metal selected by the transition metal selection step. To produce a platinum group metal fine powder and finely pulverize at least three kinds of transition metals selected in the transition metal selection step to produce a transition metal fine powder; and a fine metal powder producing step. The weight ratio of the platinum group metal fine powder and the weight ratio of the platinum group metal fine powder are set so that the composite work function of the work functions of at least three kinds of transition metal fine powders produced is close to the work function of the platinum group element. A fine powder weight ratio determining step for determining a weight ratio of at least three kinds of transition metal fine powders, and at least three kinds of transition metal fine powders having the weight ratios determined by the fine powder weight ratio determining step A fine metal powder mixture producing step of producing a fine metal powder mixture in which fine powder is mixed and dispersed, and a fine metal powder compact prepared by pressurizing the fine metal powder mixture produced by the fine metal powder mixture producing step with a predetermined pressure to obtain a fine metal powder compact. A process for producing a compressed metal fine powder, and a process for producing a compressed metal fine powder produced by the process for producing a compressed metal fine powder at a predetermined temperature to form a thin plate having a porous structure in which a large number of fine channels are formed. And a porous structure thin plate electrode producing step of producing the formed electrode.   The transition metals selected in the transition metal selection step are Ni (nickel), Fe (iron), and Cu (copper) having the lowest melting point, and in the fine powder weight ratio determination step, the metal fine powder mixture The weight ratio of the platinum group metal fine powder to the total weight is determined in the range of 5 to 10%, and the weight ratio of the Ni fine powder to the total weight of the metal fine powder mixture is in the range of 30% to 45%. The weight ratio of the Fe fine powder to the total weight of the metal fine powder mixture is determined in the range of 30% to 45%, and the weight ratio of the Cu fine powder to the total weight of the metal fine powder mixture is determined. The method for producing an electrode according to claim 10, wherein is determined in the range of 3% to 5%.   The electrode production according to claim 10 or 11, wherein the step of forming the fine metal powder pulverizes the platinum group metal to a particle size of 10 µm to 200 µm and pulverizes the transition metal to a particle size of 10 µm to 200 µm. Method.   The metal fine powder compressed material producing step pressurizes the metal fine powder mixture produced by the metal fine powder mixture producing step at a pressure of 500 Mpa to 800 Mpa, and has a thickness dimension of 0.03 mm to 0.8 mm and a large number. 13. The method for producing an electrode according to claim 10, wherein the thin metal powder compact having a porous structure in which the fine flow path is formed is formed.   In the porous structure thin plate electrode forming step, the metal fine powder compact is fired at a temperature that melts the Cu fine powder having the lowest melting point, and the molten Cu fine powder is used as a binder to form the platinum group metal fine powder. The electrode manufacturing method according to claim 10, wherein the Ni fine powder and the Fe fine powder are joined together.

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