JP2008266744A - Corrosion resistant conductive coating material, and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corrosion resistant conductive coating material which is free from consumption caused by organic matter even when used for organic electrolysis, can produce an object at the surface of an electrode with high efficiency, and can stably maintain high electrical conductivity over a long period, and to provide an inexpensive and excellently reliable corrosion resistant conductive coating material capable of withstanding for a long time even in an existing atmosphere of corrosive substances represented by iodine or the like and oxidative substances. <P>SOLUTION: The corrosion resistant conductive material is characterized in that a platinum group metal layer and/or its oxide layer thereof as an intermediate layer is formed on an electrode substrate, and a π-conjugated conductive polymer layer as an electrode catalyst substance is formed on the upper layer thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a corrosion-resistant conductive coating material that is excellent in corrosion resistance, conductivity, and durability. More specifically, the present invention relates to an electrolysis process involving oxygen generation, particularly an anode for electrolytically oxidizing organic substances, or corrosive. The present invention relates to a corrosion-resistant conductive coating material that uses an electrode for a dye-sensitized solar cell provided with an electrolyte or a separator for a polymer electrolyte fuel cell that is exposed to a corrosive environment.

  The background art will be described with reference to an example of a conventional electrode for electrolysis.

  As conventional electrodes for organic electrolysis, noble metals and carbon with high oxygen overvoltage are mainly used as water-based electrodes, and platinum is mainly used in aprotic organic solvents from the viewpoint of corrosion resistance. It has been.

  However, platinum, gold and the like are dissolved and consumed during electrolysis and are very expensive and industrially disadvantageous. In addition, the carbon electrode has a problem that it is easily oxidized when it functions as an anode and is consumed so quickly that its life is short and long-term reliability is lacking.

  Therefore, an insoluble metal electrode is known in which a catalyst coating containing a platinum group metal oxide is formed by pyrolysis on an electrode substrate such as titanium having high corrosion resistance, which is widely used in electrodes for producing chloric acid. Yes. However, since this metal electrode forms a catalyst layer by a thermal decomposition method, many cracks and pinholes are easily generated in the catalyst layer. When organic matter penetrates from these cracks, pinholes, etc., the growth of the titanium oxide layer is promoted at the interface between the catalyst layer and the titanium substrate, the electrode is made non-conductive, the reaction current efficiency is reduced, or the catalyst layer is peeled off. The electrode has a problem that it reaches the end of its life.

  As a method of modifying the electrode surface in order to achieve both the above high durability and high current efficiency, electrode particles are electrodeposited while coexisting and dissolving particles of hydrophobic substances in the electrodeposition bath. There has been proposed a method of forming a composite material layer in which electrodeposits are taken into an electrodeposition layer to form an electrode. On the hydrophobic electrode produced in this way, organic molecules are easily adsorbed on the electrode surface, resulting in an increase in the concentration of organic matter on the electrode surface, and current efficiency is improved. However, in the electrodeposition method, there are some noble metal species that are difficult to deposit depending on the type of noble metal used as the electrode catalyst. In addition, there is a problem that it is difficult to control the composition ratio between the hydrophobic substance and the catalyst substance.

  On the other hand, instead of the electrodeposition method, there is a method to control various catalyst materials and hydrophobic materials to an arbitrary mixing ratio by mixing and molding a hydrophobic material, a catalyst material, and a binder. The electrode has a problem in terms of mechanical strength. In addition, it is not easy to mix each substance uniformly, and the hydrophobic performance is limited.

  Accordingly, conventional electrodes for organic electrolysis are insufficient from the viewpoint of achieving both long electrode life and high reaction current efficiency, and there is a demand for electrode materials that combine these characteristics, are inexpensive, and have excellent productivity. .

  In addition, the performance required for the dye-sensitized solar cell electrode has both of the above characteristics, that is, good conductivity for efficiently transmitting electrons excited on the titania electrode side, and direct sunlight. And durability at high temperatures. In general, iodine is mixed as an oxidation-reduction pair in an electrolyte of a dye-sensitized solar cell. However, since the iodine is very corrosive, electrode materials are required to have high corrosion resistance.

  Almost no electrode materials for dye-sensitized solar cells using inexpensive metal substrates have been proposed except in some cases. For example, what is disclosed in Non-Patent Document 1 is mainly intended to have both heat resistance and flexibility. A silicon oxide thin film is formed on a stainless steel substrate, and a conductive metal oxide is formed thereon. However, there is a problem that the obtained solar cell characteristics are greatly deteriorated due to insufficient practical durability and high electrical resistance of the material itself. Therefore, generally, a glass substrate electrode coated with a conductive metal oxide such as ITO or FTO that does not corrode with iodine is used. In particular, as a counter electrode, an electrode coated with platinum having a catalytic action for reducing the oxidized form of the redox pair and having corrosion resistance is used.

  Such metal oxide-coated electrodes have the problem of high manufacturing costs, such as the need for large-scale equipment, and the conductivity of the electrodes is also insufficient. There was a problem that would decrease. Also, the platinum-coated electrode has a problem that the material cost is high, and it is known that it dissolves in an organic solvent that is generally used as an electrolyte solvent in the presence of water or oxygen. There was also a problem in terms of stability. Accordingly, there is a need for a dye-sensitized solar cell electrode material that can still be produced with a lower manufacturing cost and process, and that has good conductivity and high corrosion resistance.

  As mentioned above, although the prior art regarding the electrode for organic electrolytic synthesis and the electrode for dye-sensitized solar cells was demonstrated, the patent document 1 by the present applicant is disclosed regarding the corrosion-resistant conductive coating material. This patent document discloses a corrosion-resistant conductive coating material in which a conductive intermediate layer is formed on a metal substrate and then a π-conjugated conductive polymer layer is formed, but is included in the conductive intermediate layer. There was a problem that the electrical resistance of the material itself was likely to be high due to the insulating resin component. Furthermore, the conductive intermediate layer has insufficient adhesion to a general-purpose metal, and there is a problem that the conductivity is gradually lost over time, and further improvement in characteristics is required.

JP 2006-167925 A Man Gu Kang, 4 others, “A 4.2% effective flexible dye-sensitized TiO2 solar cells using stain steel substage”, Solar Energy 90. 574-581

  An object of the present invention is to provide a corrosion-resistant conductive coating material that can be efficiently produced on the electrode surface even when it is used for organic electrolysis, can efficiently produce the object, and can maintain high conductivity stably for a long period of time. It is another object of the present invention to provide a corrosion-resistant conductive coating material that can withstand a long time even when used in the presence of a corrosive substance or an oxidative substance typified by iodine or the like and that is inexpensive and excellent in reliability.

  That is, the present invention is as follows.

(1) A corrosion-resistant conductive coating characterized in that an intermediate layer comprising a platinum group metal layer and / or an oxide layer thereof is formed on a substrate, and a π-conjugated conductive polymer layer is formed thereon. material.

(2) The corrosion resistance according to (1), wherein the substrate is at least one metal substrate selected from the group consisting of titanium, zirconium, niobium, tantalum, aluminum, and iron and / or an alloy thereof. Conductive coating material.

(3) The intermediate layer composed of the platinum group metal layer and / or its oxide layer contains at least one platinum group metal selected from the group consisting of iridium, ruthenium, rhodium, palladium and platinum and / or its oxide. The corrosion-resistant conductive coating material as described in (1) or (2) above.

(4) The platinum group metal layer and / or the oxide layer thereof,
Any of the above (1) to (3), which is a platinum group metal layer and / or an oxide layer thereof formed by applying, drying and firing a coating solution comprising an alcohol solution of a platinum group metal organic compound. The corrosion-resistant conductive coating material according to crab.

(5) The (1) to (1) above, wherein the π-conjugated conductive polymer layer is at least one selected from the group consisting of polypyrrole or a derivative thereof, polyaniline or a derivative thereof, polythiophene or a derivative thereof. 4) The corrosion-resistant conductive coating material according to any one of 4).

(6) The corrosion-resistant conductive coating material according to any one of (1) to (5), wherein the application is an electrode for electrolysis.

(7) The corrosion-resistant conductive coating material according to any one of (1) to (5), wherein the use is an electrode for a dye-sensitized solar cell.

(8) The corrosion-resistant conductive coating material according to any one of (1) to (5), wherein the application is a fuel cell separator.

(9) A step of applying a coating solution comprising an alcohol solution of a platinum group metal organic compound on a substrate, drying and baking to form a platinum group metal layer and / or an oxide layer thereof, and then on the layer Corrosion-resistant conductive coating material comprising a step of polymerizing a π-conjugated conductive polymer monomer and forming a π-conjugated conductive polymer layer on the platinum group metal layer and / or its oxide layer Manufacturing method.

(10) The method for producing a corrosion-resistant conductive coating material according to (9), wherein the firing step is a firing step by heat treatment at 350 ° C. or higher.

  According to the present invention, a platinum group metal layer formed by heat treatment and / or an oxide layer thereof is formed between a specific metal substrate and a π-conjugated conductive polymer layer. Adhesion with the π-conjugated conductive polymer layer is improved, and conductivity and corrosion resistance are remarkably improved.

  That is, the conductive metal oxide layer and the platinum group metal layer and / or the oxide layer formed on the surface of the metal substrate by heat treatment are excellent in corrosion resistance and conductivity, and the π-conjugated conductive polymer film and the metal substrate. Can be maintained and maintained well over a long period of time. As a result, the π-conjugated conductive polymer layer effectively acts as a catalyst for the electrode surface layer, and the contact efficiency between the reactant and the electrode is improved, so that high current efficiency can be achieved particularly in organic electrolysis. It becomes.

  Furthermore, in the electrode for a dye-sensitized solar cell, the contact efficiency with an electrode improves with respect to electrolyte, and it becomes possible to use the metal base material which is excellent in mass productivity, without reducing a power generation characteristic.

  In the corrosion-resistant conductive coating material of the present invention, the substrate to be used is a metal substrate. In particular, when used as an anode, titanium, zirconium, niobium, tantalum, aluminum, iron and the like are used from the viewpoint of corrosion resistance to an oxidizing use environment. It is preferably at least one metal substrate selected from the group consisting of alloys as the main component. In order to reinforce the adhesion between the substrate and the π-conjugated conductive polymer layer, the surface of the substrate may be blasted or etched to increase the surface area and roughen the surface in advance. preferable.

  After blasting or etching, the surface is selectively etched to clean and activate. Typical examples of the acid cleaning in this cleaning are sulfuric acid, hydrochloric acid, hydrofluoric acid, and the like, and activation can be performed by immersing the metal substrate in these solutions to dissolve a part of the surface.

  Next, a platinum group metal layer and / or an oxide layer thereof as an intermediate layer is formed on the surface of the activated metal substrate. The platinum group metal layer and / or its oxide layer is preferably formed by a method such as a thermal decomposition method or a sol-gel method.

  The component of the platinum group metal layer and / or its oxide layer is preferably made of iridium, ruthenium, rhodium, palladium, platinum, and an organometallic compound or chloride of each metal is dissolved in a solvent such as alcohol. To prepare a coating solution.

  Furthermore, it is preferable to add conductivity, corrosion resistance by adding an organometallic compound or chloride of titanium, zirconium, tantalum, niobium, aluminum, tin to the coating solution. As a ratio to be added, it is preferable that the coating liquid is prepared so as to be 20 to 48 mol% for tantalum, aluminum and niobium, and 5 to 20 mol% for titanium, zirconium and tin.

  A coating method for forming the intermediate layer is not particularly limited, and a conventionally known coating method can be used, and a spray coating method, a dip coating method, a brush coating method, a spin coating method, or the like can be used.

  After the metal substrate coated with the coating liquid is dried at 50 to 100 ° C. for about 10 minutes, the platinum group metal layer and / or its layer is subjected to a thermal decomposition method in which heat treatment is performed at 350 ° C. or higher, more preferably 380 to 550 ° C. An oxide layer is formed.

  In the above pyrolysis process, since the metal substrate is also heated at a high temperature, an extremely thin insulating metal oxide is simultaneously formed on the outermost surface of the metal substrate. However, the platinum group metal layer and / or oxide particles thereof formed by heat treatment penetrate into the metal oxide layer by thermal diffusion. That is, a mixed layer in which a platinum group metal layer and / or oxide particles thereof are dispersed in the metal oxide layer is formed, and an insulating metal is formed through the platinum group metal layer and / or oxide particles thereof. Conductive paths are formed in the oxide layer. As a result, good conductivity between the metal substrate and the platinum group metal layer and / or its oxide can be maintained.

  The platinum group metal layer and / or oxide layer thereof, and the mixed layer in which the platinum group metal layer and / or oxide particles thereof are dispersed in the metal oxide layer have a function of protecting the metal substrate. However, if the process from coating to thermal decomposition is repeated a plurality of times, the thickness of the platinum group metal layer and / or its oxide layer increases, the oxide layer of the base metal surface layer grows at the same time, and there are many pinholes and cracks. It generates and adversely affects the conductivity and corrosion resistance of the corrosion-resistant conductive coating material. On the other hand, if the thickness is too thin, the protective function for the base metal is lowered. Therefore, the thickness is preferably in the range of 5 nm to 200 nm so that the electrical conductivity and the protective function can be expressed highly, but from the economic viewpoint, the range of 5 nm to 100 nm. Is more preferable.

  Next, in order to further improve the corrosion resistance and conductivity of the metal substrate and the platinum group metal layer and / or its oxide layer, and to make the surface of the corrosion-resistant conductive coating material hydrophobic so that the contact with the organic compound is efficient. Then, a π-conjugated conductive polymer film is formed. There are many methods for forming a film of a π-conjugated conductive polymer, such as a chemical polymerization method, an electrolytic polymerization method, and a solution method, and an appropriate method depends on the type and form of the target π-conjugated conductive polymer. You can choose the method.

  The type of the π-conjugated conductive polymer used in the present invention is not particularly limited, but polypyrrole or a derivative thereof, polythiophene such as polyalkylthiophene or polyalkylenedioxythiophene or a derivative thereof, polyaniline or a derivative thereof is preferable. .

  In order to obtain a high barrier property for protecting the substrate from high electrical conductivity and corrosive environment, the electrolytic polymerization method or solution method is suitable for polypyrrole or its derivatives, and the electrolytic polymerization method or solution method for polyalkylthiophenes or its derivatives. Alternatively, a chemical polymerization method is preferable, a chemical polymerization method is preferable for polyalkylenedioxythiophene or a derivative thereof, and an electrolytic polymerization method or a solution method is preferable for polyaniline or a derivative thereof. In particular, a π-conjugated conductive polymer film formed by an electropolymerization method has high electrical conductivity due to a high doping rate, and has a high orientation and dense π-conjugated conductive property compared to other formation methods. Since a molecular film can be obtained easily, it is most preferable.

  In addition, the environment in which metals are corroded is not limited to an acidic atmosphere such as an aqueous sulfuric acid solution. For example, in a dye-sensitized solar cell, an oxidizing atmosphere is similarly formed by iodine as an electrolyte, and an oxidizing atmosphere is formed by oxygen gas on the oxygen electrode side in the fuel cell. Under such circumstances, certain dopants may cause the electrical conductivity of the π-conjugated conductive polymer to be lost. Therefore, in an oxidative corrosion environment, an anionic compound that is a dopant of a π-conjugated conductive polymer needs to be excellent in oxidation resistance. Therefore, it is preferable to use an anionic compound having a sulfonic acid group or a heteropolyacid group as a dopant for a π-conjugated conductive polymer film that exhibits high electrical conductivity, excellent oxidation resistance, and high corrosion resistance. is there. The number of sulfonic acid groups or heteropolyacid groups in the compound is not particularly limited.

  When the molecular weight of the anionic compound is less than 240, that is, when the molecule is small, the dedoping action is easily generated, and the electrical conductivity of the π-conjugated conductive polymer is lost. In order to prevent this phenomenon, an anionic compound having a large molecule is suitable, and its molecular weight is preferably 240 or more. Specific examples of anionic compounds having one or more sulfonic acid groups or heteropolyacid groups and having a molecular weight of 240 or more include alkylnaphthalene sulfonate ions, lignin sulfonate ions, molybdophosphate ions, and tungstophosphate ions. can do. In addition, a π-conjugated conductive polymer film containing such an anionic compound is dense and has a favorable barrier effect for blocking the corrosive environment from the substrate.

  As a method for forming the π-conjugated conductive polymer film using an anionic compound having a sulfonic acid group or a heteropolyacid group and having a molecular weight of 240 or more as a dopant, for example, when forming a polypyrrole film, A metal substrate on which a platinum group metal layer and / or an oxide layer thereof is formed by dissolving pyrrole as a monomer and sodium alkylnaphthalenesulfonate as a supporting electrolyte, tetraethylammonium molybdophosphate in an aqueous solution, and an oxide layer thereof is an anode, a stainless steel substrate, etc. A polypyrrole film can be obtained by an electropolymerization method in which electrolysis is performed using as a cathode. The electrolytic polymerization method for forming a film of polypyrrole or polyaniline is easy to obtain a π-conjugated conductive polymer film having a dense and highly regular electric conductivity, and is excellent in corrosion resistance because of excellent barrier properties.

  In the chemical polymerization method, a π-conjugated conductive polymer film having high corrosion resistance can be formed by contacting a target π-conjugated conductive polymer monomer with an oxidant solution on the substrate surface. it can. For example, in the case of forming a poly-3,4-ethylenedioxythiophene film, the monomer 3,4-ethylenedioxy is formed on the metal substrate on which the platinum group metal layer and / or its oxide layer is formed. A poly-3,4-ethylenedioxythiophene coating can be obtained by bringing a butanol-water mixed solution containing thiophene and iron (III) naphthoquinonesulfonate as an oxidizing agent into contact with each other. The chemical polymerization method for forming a polythiophene film is easy to obtain a π-conjugated conductive polymer film in which fine particles are densely packed, and is excellent in corrosion resistance because of excellent barrier properties.

  In the solution method, a monomer of a π-conjugated conductive polymer, an oxidant solution, and a dopant solution are brought into contact with each other for polymerization, and the obtained polymer is dried and then dissolved in an organic solvent to obtain a coating solution. By applying and drying the coating solution on a metal substrate on which a platinum group metal layer and / or its oxide layer is formed, a desired π-conjugated conductive polymer film having high corrosion resistance can be formed. For example, in the case of forming a film of 3-hexylthiophene, 3-hexylthiophene, ammonium peroxodisulfate as an oxidizing agent, and sodium ferrocenesulfonate as a dopant are dissolved in an ethanol-water mixed solution and polymerized while stirring. The coating liquid can be obtained by proceeding and dissolving the obtained poly-3-hexylthiophenethiophene in toluene after drying. A polyalkylthiophene film can be obtained by applying the coating liquid onto a metal substrate in which conductive fine particles are embedded in etching holes and then drying the coating.

  As a method of forming the π conductive polymer film by the solution method, a conventionally known method can be used and is not particularly limited. For example, screen printing method, dip coating method, roll coating method, spraying method, curtain flow coating method, bar coating method, doctor blade method, brush coating method, etc., there are simple and highly productive dip coating method, brush coating The method is preferred.

  As described above, the formation of the conductive polymer film proceeds by an oxidation reaction. For this reason, since the surface of the metal substrate is exposed to an oxidizing atmosphere when the conductive polymer is formed, a metal oxide layer derived from an insulating base material is formed on the surface of the metal substrate that is not treated at all, and acts as a conductive material. Disappear. However, in the present invention, electrons are transferred from the metal substrate to the surface of the corrosion-resistant conductive coating material by the platinum group metal layer and / or its oxide layer formed in the firing process and the oxide layer derived from the substrate on which the conductive path is formed. A path is formed. Therefore, a conductive metal oxide layer is formed at the time of forming the conductive polymer film, so that it does not work as a conductive material, and it is possible to maintain good electrical characteristics of the metal.

  As described above, by covering the platinum group metal layer and / or its oxide layer with the π-conjugated conductive polymer film, the conductivity and corrosion resistance can be greatly improved. The platinum group metal layer and / or the oxide layer thereof are very thin and are scattered in islands, resulting in poor conductivity. However, by covering with the π-conjugated system conductive polymer film, the entire surface of the material becomes conductive, so that the conductivity is improved, and pinholes and cracks generated in the heat treatment process are removed from the π-conjugated system conductive polymer. This is because the corrosion resistance is also improved by covering the film.

  In addition, by forming the π-conjugated system conductive polymer after the bending process such as press processing, cutting, etching, etc. on the substrate in advance, the π-conjugated system conductivity is formed when forming a complex-shaped substrate. The effect of the π-conjugated conductive polymer film can be reliably obtained without damaging the polymer film. For example, regarding the formation of a π-conjugated conductive polymer film, if electrolytic polymerization is performed using the processed substrate as an electrode as described above, even if the substrate surface is uneven due to processing, the π-conjugated conductive property is uniformly obtained. A polymer film can be formed, and stable performance can be obtained.

  The thickness of the π-conjugated conductive polymer layer to be formed is suitably 0.001 μm to 100 μm, but is preferably 0.01 μm to 50 μm, and most preferably 0.1 μm to 35 μm from the economical viewpoint.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited at all by the Example. In this example, wt% refers to mass%.

Example 1
A Ti substrate (JIS type 2) was used as the metal substrate. The Ti substrate is a rolled material having a size of 20 × 30 mm and a thickness of 0.5 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide substrate was removed by immersion in 3N hydrochloric acid for 30 seconds to complete the Ti substrate surface treatment step.

The intermediate layer coating solution was prepared by mixing 3.00 g of iridium trichloride trihydrate, 0.51 g of titanium tetra-n-butoxide, 2 ml of 6N hydrochloric acid, 45 ml of butanol and 3 ml of acetylacetone and stirring for 3 hours in a nitrogen atmosphere. It was adjusted. After applying the Ti substrate after the surface treatment step by the dip method, a heat treatment is performed at 420 ° C. for 1 hour, thereby forming an IrO ₂ —TiO ₂ layer having a thickness of 90 nm and a TiO ₂ layer in which a conductive path is formed.

Next, a π-conjugated conductive polymer film containing a compound having a sulfone group as a dopant is formed on the substrate by electrolytic polymerization. The Ti substrate on which the intermediate layer was formed was made into an anode using an electrolytic solution containing pure water as a solvent, pyrrole 0.5 mol / L as a monomer, and sodium 2,7-naphthalenedisulfonate 0.30 mol / L as a supporting electrolyte. SUS304 was used as the cathode, the electropolymerization time was 1 hour, the current density was 1 mA / cm ² , electropolymerization was performed to form a 25 μm-thick polypyrrole film, and a total of 10 corrosion-resistant conductive coating materials were produced.

(Example 2)
A Ti substrate (JIS type 2) was used as the metal substrate. The Ti substrate is a rolled material having a size of 20 × 30 mm and a thickness of 0.5 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide substrate was removed by immersion in 3N hydrochloric acid for 30 seconds to complete the Ti substrate surface treatment step.

An intermediate layer coating solution was prepared by mixing 2.82 g of iridium trichloride trihydrate, 1.43 g of tantalum pentachloride, 10 ml of 12N hydrochloric acid, and 40 ml of butanol and stirring for 3 hours in a nitrogen atmosphere. After applying the surface treatment process Ti substrate by dipping method, heat treatment is performed at 420 ° C. for 1 hour to form a 50 nm thick IrO ₂ —Ta ₂ O ₃ layer and a TiO ₂ layer in which a conductive path is formed. did.

Next, a π-conjugated conductive polymer film containing a compound having a heteropolyacid group as a dopant is formed by electrolytic polymerization. Using a pure water as a solvent, an electrolyte containing 0.5 mol / L of pyrrole as a monomer and 0.30 mol / L of silicotungstic acid as a supporting electrolyte, a Ti substrate on which an intermediate layer is formed is an anode, SUS304 is a cathode, The electropolymerization time was 2 hours, the current density was 0.25 mA / cm ² , electropolymerization was performed to form a 18 μm-thick polypyrrole film, and a total of 10 corrosion-resistant conductive coating materials were produced.

(Example 3)
An Nb substrate was used as the metal substrate. The Nb substrate is a rolled material having a size of 20 × 30 mm and a thickness of 0.1 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide film was removed by immersing in 1N hydrofluoric acid for 1 minute to complete the Nb substrate surface treatment step.

Ruthenium trichloride n-hydrate (2.03 g), titanium tetra-n-butoxide (0.34 g), 6N hydrochloric acid (2 ml), butanol (45 ml), and acetylacetone (3 ml) were mixed and stirred for 8 hours in a nitrogen atmosphere to obtain a coating solution for an intermediate layer. It was adjusted. After applying the Nb substrate after the surface treatment step by a dip method, heat treatment was performed at 490 ° C. for 1 hour, thereby forming a RuO ₂ —TiO ₂ layer having a thickness of 80 nm and an NbO ₂ layer in which a conductive path was formed.

  Next, a π-conjugated conductive polymer film having high corrosion resistance and containing a compound having a sulfonic acid group as a dopant is formed by electrolytic polymerization. Use pure water as solvent, 0.1 mol / L aniline as monomer, 0.15 mol / L polyvinyl sulfonic acid as supporting electrolyte, Au as cathode, see silver / silver chloride (saturated KCl) Electrode, electrode electropolymerization time is 1 hour, electrolysis voltage is 0.5 V (vs silver / silver chloride reference electrode), constant potential electropolymerization is performed for 10 minutes, 31 μm-thick polyaniline film is formed, and the corrosion-resistant conductive coating material is totaled Ten sheets were produced.

(Reference Example 1)
In Example 3, in the step of forming the π-conjugated conductive polymer film, a polyaniline film was formed in the same manner except that polyvinyl carboxylic acid was used as the supporting electrolyte, and a total of 10 coating materials were produced. .

Example 4
An SS330 substrate, which is an Fe-based substrate, was used as the metal substrate. The SS330 substrate is a rolled material having a size of 20 × 30 mm and a thickness of 0.1 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide film was removed by immersion in 1N hydrofluoric acid for 1 minute to complete the SS330 substrate surface treatment step.

Ruthenium trichloride n-hydrate (2.03 g), aluminum tri-n-butoxide (1.48 g), 6N hydrochloric acid (2 ml), butanol (45 ml), and acetylacetone (3 ml) were mixed and stirred for 8 hours in a nitrogen atmosphere to obtain an intermediate layer coating solution. It was adjusted. After applying the Fe substrate after the surface treatment process by a brush coating method, a heat treatment is performed at 450 ° C. for 1 hour in a nitrogen atmosphere containing 1% oxygen, whereby a RuO ₂ —Al ₂ O ₃ layer having a thickness of 80 nm and a conductive layer are formed. A Fe ₂ O ₃ layer in which a path was formed was formed.

  150 g of water and 10.1 g of concentrated hydrochloric acid were added to 9.3 g of aniline, and a solution obtained by dissolving 22.8 g of ammonium persulfate in 40 g of water was added dropwise over 2 hours while maintaining the temperature at 0 to 10 ° C., followed by stirring for 3 hours. Thereafter, 41 g of concentrated aqueous ammonia was added dropwise over 1 hour, and the mixture was further stirred for 5 hours. After filtration, water washing and methanol washing were repeated, and vacuum drying was performed to obtain 8.3 g of copper-colored polyaniline. The obtained copper-colored polyaniline was dispersed in 200 ml of methanol, added with 20 g of hydrazine monohydrate, stirred at room temperature for 15 hours, filtered, washed with water and methanol, and vacuum-dried to obtain a grayish blue soluble 7.5 g of polyaniline was obtained. Furthermore, it melt | dissolved in N-methyl-2-pyrrolidone so that it might become 3.5 wt% of indigo trisulfonic acid and 2.0 wt% of polyaniline, and the polyaniline solution containing a dopant was obtained.

  Next, a π-conjugated conductive polymer film having high corrosion resistance is formed by a solution method. By immersing the SS330 substrate on which the intermediate layer is formed in the previously prepared polyaniline solution and drying it at a temperature of 150 ° C. for 10 minutes twice, a polyaniline film having a thickness of 24 μm is formed, and a corrosion-resistant conductive coating material is formed. A total of 10 sheets were produced.

(Reference Example 2)
An Nb substrate was used as the metal substrate. The Nb substrate is a rolled material having a size of 20 × 30 mm and a thickness of 1 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide film was removed by immersing in 1N hydrofluoric acid for 1 minute to complete the Nb substrate surface treatment step.

Mixing ruthenium trichloride nhydrate 2.03g, aluminum tri-n-butoxide 1.48g, 6N hydrochloric acid 2ml, butanol 45ml, acetylacetone 3ml, and stirring for 8 hours under nitrogen atmosphere, the coating solution for the intermediate layer It was adjusted. After the Nb substrate having been subjected to the surface treatment process is applied by a brush coating method, a heat treatment is performed at 450 ° C. for 1 hour, whereby a RuO ₂ —Al ₂ O ₃ layer having a thickness of 80 nm and an NbO ₂ layer in which a conductive path is formed are obtained. Formed.

  Next, a polyaniline film, which is a π-conjugated conductive polymer, was formed by chemical polymerization. 150 g of water and 10.1 g of concentrated hydrochloric acid were added to 9.3 g of aniline, and a solution obtained by dissolving 22.8 g of ammonium persulfate in 40 g of water was added dropwise over 2 hours while maintaining the temperature at 0 to 10 ° C., followed by stirring for 3 hours. Thereafter, 41 g of concentrated aqueous ammonia was added dropwise over 1 hour, and the mixture was further stirred for 5 hours, followed by filtration, repeated washing with water and methanol, and then vacuum drying to obtain 8.3 g of copper-colored polyaniline. The obtained copper-colored polyaniline was dispersed in 200 ml of methanol, added with 20 g of hydrazine monohydrate, stirred at room temperature for 15 hours, filtered, washed with water and methanol, and vacuum-dried to obtain a grayish blue soluble 7.5 g of polyaniline was obtained. Furthermore, in addition to toluene solvent so that it might become 3.5 wt% of indigo trisulfonic acid, 2.0 wt% of polyaniline, and 1.0 wt% of dodecylbenzenesulfonic acid, the polyaniline dispersion liquid containing a dopant was obtained.

  The polyaniline film is formed by immersing the Nb substrate on which the intermediate layer has been formed in the polyaniline dispersion prepared as described above and drying it at a temperature of 150 ° C. for 5 minutes to form a polyaniline film, and a total of 10 coating materials. Produced.

(Example 5)
A Zr substrate was used as the metal substrate. The Zr substrate is a rolled material having a size of 20 × 30 mm and a thickness of 0.1 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide film was removed by immersion in 6N hydrochloric acid for 1 minute, and the Zr substrate surface treatment step was completed.

Chloroplatinic acid hexahydrate 4.40g, tin tetrachloride pentahydrate 0.53g, 6N hydrochloric acid 2ml, butanol 40ml, cyclohexanol 10ml were mixed and applied for intermediate layer by stirring for 8 hours under nitrogen atmosphere The liquid was adjusted. The Zr substrate after the surface treatment process was applied by a brush coating method and then heat-treated at 500 ° C. for 1 hour, thereby forming a 75-nm-thick Pt—SnO ₂ layer and a ZrO ₂ layer in which a conductive path was formed.

  Subsequently, in ethanol / water mixed solvent whose pH was adjusted to 7, 3-hexylthiophene 0.4 mol / L, 0.20 mol of iron (III) 2,6-anthraquinone disulfonate acting as an oxidizing agent and a dopant agent / L was stirred under ice bath temperature for 6 hours. After filtering the solution, the obtained powder was dried under reduced pressure to completely remove the solvent, and the powder was dissolved in a toluene solution to obtain a poly-3-hexylthiophene solution.

  Next, a π-conjugated conductive polymer film having high corrosion resistance is formed by a solution method. After applying the previously prepared coating solution onto the Zr substrate on which the intermediate layer has been uniformly formed by spraying, the process of removing toluene in a dryer at 70 ° C. is repeated to form a poly-3-hexylthiophene film having a thickness of 15 μm. Then, 10 sheets of corrosion-resistant conductive coating material were produced.

(Reference Example 3)
In Example 5, a polythiophene film was formed in the same manner except that the heat treatment temperature of the intermediate layer was 200 ° C., and a total of 10 coating materials were produced.

(Example 6)
A Ta substrate was used as the metal substrate. The Ta substrate is a rolled material having a size of 20 × 30 mm and a thickness of 0.1 mm. The substrate was finished with a satin finish by shot blasting using a zircon shot. Next, after degreasing treatment with an organic solvent, the oxide film was removed by immersion in 1N hydrofluoric acid for 1 minute, and the Ta substrate surface treatment step was completed.

The intermediate layer coating solution was prepared by mixing 1.99 g of rhodium acetate, 0.46 g of penta-n-butoxyniobium, 2 ml of 6N acetic acid, 40 ml of butanol and 8 ml of acetylacetone and stirring for 24 hours in a nitrogen atmosphere. After applying the Ta substrate having been subjected to the surface treatment step by spin coating, heat treatment was performed at 500 ° C. for 1 hour, thereby forming a 47 nm thick Rh—NbO ₂ layer and a TaO ₂ layer in which a conductive path was formed.

  Next, a π-conjugated conductive polymer film having high corrosion resistance is formed by a chemical polymerization method. An ethanol-water mixed solution containing poly-3,4-ethylenedioxythiophene as a monomer and tetraethylammonium polystyrene sulfonate (average molecular weight 100,000) as a dopant agent on the surface of a Ta substrate on which an intermediate layer is formed After coating, an iron (III) chloride aqueous solution that is an oxidizing agent solution is sprayed, and the process of drying at 50 ° C. for 10 minutes is repeated to form a poly-3,4-ethylenedioxythiophene film having a thickness of 21 μm, Ten sheets of corrosion-resistant conductive coating material were produced.

(Reference Example 4)
In Example 6, the formation temperature of the intermediate layer was 250 ° C., and the process of forming the π-conjugated conductive polymer film was carried out in the same manner except that tetraethylammonium styrenesulfonate was used as the dopant agent. , 4-ethylenedioxythiophene film was formed, and a total of 10 coating materials were produced.

(Example 7)
An AL7050 substrate was used as the metal substrate. The AL7050 substrate is a rolled material having a size of 20 × 30 mm and a thickness of 1.0 mm. The substrate was satin-finished with # 120 water-resistant abrasive paper. Next, after degreasing treatment with an organic solvent, the oxide film was removed by immersion in 0.1N hydrochloric acid for 1 minute, and the AL 7050 substrate surface treatment step was completed.

Palladium acetylacetonate (2.83 g), zirconium tetra-n-butoxide (0.22 g), butanol (45 ml), acetylacetone (4.5 ml), and water (0.5 ml) are mixed and stirred at 80 ° C. for 24 hours in a nitrogen atmosphere. The coating solution was adjusted. After the surface treatment process is finished, the AL7050 substrate is applied by spin coating, and then heat treated at 390 ° C. for 10 minutes in a nitrogen atmosphere containing 1% oxygen to form a Pd—ZrO ₂ layer having a thickness of 28 nm and a conductive path. An Al ₂ O ₃ layer was formed.

  A π-conjugated conductive polymer film is formed by a chemical polymerization method. On the surface of the AL7050 substrate on which the intermediate layer is formed, after applying an aqueous solution containing pyrrole as a monomer and iron (III) 2,7-naphthalenedisulfonate as an oxidizing agent, a process of drying at 50 ° C. for 10 minutes is repeated. A polypyrrole film having a thickness of 3 μm was formed.

Subsequently, a π-conjugated conductive polymer film having high corrosion resistance is formed by an electrolytic polymerization method. The AL7050 substrate is coated with chemically polymerized polypyrrole using an electrolytic solution containing pure water as a solvent, 0.5 mol / L of pyrrole as a monomer, and 0.30 mol / L of dodecylbenzenesulfonic acid as a supporting electrolyte. SUS304 was used as the cathode, the electropolymerization time was 1 hour, the current density was 1 mA / cm ² , electropolymerization was performed to form a polypyrrole film having a thickness of 18 μm, and a total of 10 corrosion-resistant conductive coating materials were produced.

(Comparative Example 1)
In Example 1, a polypyrrole film was formed in the same manner except that the intermediate layer was not formed, and a total of 10 coating materials were produced.

(Comparative Example 2)
In Example 2, sodium hexabromoiridate 0.055 mol / dm ³ , boric acid 0.30 mol / dm ³ , sodium oxalate 0.30 mol / dm ³ , adjusted to pH 4 with aqueous ammonia, at a good temperature of 85 ° C. Using a plating solution, a polypyrrole film was formed in the same manner except that an Ir plating layer having a thickness of 88 nm was formed on the Ti substrate having been subjected to the surface treatment step under a current density of 1.0 mA / cm ² . A total of 10 coating materials were produced.

(Comparative Example 3)
After subjecting the AL7050 substrate to surface treatment in the same manner as in Example 7, a 55 nm carbon layer was formed from a commercially available carbon paste agent as an intermediate layer, thereby producing an AL7050 substrate having the intermediate layer formed thereon.

  Subsequently, a π-conjugated conductive polymer film is formed by a chemical polymerization method. On the surface of the AL7050 substrate on which the intermediate layer is formed, after applying an aqueous solution containing pyrrole as a monomer and iron (III) 2,7-naphthalenedisulfonate as an oxidizing agent, a process of drying at 50 ° C. for 10 minutes is repeated. A polypyrrole film having a thickness of 27 μm was formed, and a total of 10 corrosion-resistant conductive coating materials were produced.

(Evaluation of usage of each material)
1: Evaluation as an electrode for organic electrolysis The corrosion-resistant conductive coating material according to the present invention produced in this way and the material produced in the comparative example were allowed to act as an electrode for electrolysis, and a chlorobromophenol derivative, argon gas, By bubbling in the electrolytic solution, it was subjected to electrolytic oxidation in an argon atmosphere and compared (reaction formula 1). Corrosion-resistant conductive coating materials prepared in Examples and Comparative Examples were adjusted to an anode, a platinum plate as a cathode, methanol as a solvent, lithium perchlorate as a supporting electrolyte, pyridine as a basic additive, and 0.5 mM as a substrate concentration. Using the electrolytic solution, the anodic oxidation reaction was carried out by a batch method so that the amount of current supplied was 3.0 F / mol by constant current electrolysis at 100 mA / cm ² . After completion of the reaction, the product was analyzed by GC-MS, and the results of calculating the current efficiency are shown in Table 1. For comparison, Table 1 also shows the case where a platinum electrode, which is a dimensionally stable electrode produced by a firing method, was used. Furthermore, with respect to the corrosion-resistant conductive coating materials according to Examples 1 to 3, Comparative Examples 1 to 2, and Reference Example 1, the above-described electrolytic test was performed 1000 times, and current efficiency and interelectrode voltage were measured at each test. The results are shown in Table 2.

Ｒ：（ＣＨ_２）_３ＯＡｃ

R: (CH ₂ ) ₃ OAc

2: Evaluation as an electrode for a dye-sensitized solar cell Next, the prepared corrosion-resistant conductive coating material according to the present invention and the material prepared in the comparative example are maintained at 50 ° C., which is a simulated liquid close to the operating environment of the solar cell. The 4 wt% I ₂ and iodide salt-containing acetonitrile solution was subjected to an immersion test for 30 days, and the concentration of metal ions eluted from the metal substrate into the simulated solution was measured by a sequential type high-frequency plasma emission spectrometer, and was resistant to corrosion. Table 3 shows the result of comparison. Table 4 shows the results of comparing the initial surface resistance and the surface treatment resistance after the immersion test by the surface resistance measurement shown in FIG. For comparison, this test also shows a case where a fired platinum electrode having a thickness of 2 μm whose base is Ti is used.

Furthermore, the dye-sensitized solar cell was produced using the electrode in Example 4 and Reference Example 2 as a counter electrode. Further, for Example 4 and Reference Example 2, an immersion test was performed for 30 days using a 4 wt% I ₂ and iodide salt-containing acetonitrile solution maintained at 50 ° C., which is a simulated solution close to the solar cell operating environment. Table 5 shows the results of evaluation of changes in solar cell characteristics before and after the immersion test in the same manner.
That is, FTO glass (25 mm x 50 mm made by Nippon Sheet Glass) was used as a transparent substrate with a transparent conductive film, and a titanium dioxide paste (made by Showa Denko) was applied to the surface with a bar coater, dried and baked at 450 ° C. for 30 minutes. The porous titanium oxide semiconductor electrode having a thickness of 10 μm was formed as it was until the temperature reached room temperature.

Then, it moved to the dye adsorption process. In an ethanol solution prepared using a bis (4,4′-dicarboxy-2,2′-bipyridine) diisothiocyanate ruthenium complex generally called N3dye as a sensitizing dye and having a dye concentration of 0.5 mmol / L The porous titanium oxide semiconductor electrode once heated to 150 ° C. was immersed and allowed to stand overnight under light shielding. Thereafter, excess pigment was washed with ethanol and then air-dried to produce a semiconductor electrode of a solar cell. Furthermore, the semiconductor layer was ground so that the projected area of titanium oxide of the obtained semiconductor electrode was 25 mm ² .

The semiconductor electrode produced as described above and the electrode produced in Example 4 or Reference Example 2 were placed as a counter electrode so as to face the semiconductor electrode, and an electrolyte was impregnated between both electrodes by capillary action. As the electrolyte, a solution containing methoxyacetonyl as a solvent, lithium iodide as a reducing agent, iodine as an oxidizing agent, t-butylpyridine as an additive, and 1,2-dimethyl-3-propylimidazolium iodide was used.
About the above-mentioned solar battery cell, a mask for light irradiation area regulation with a 5 mm square window is attached, and then a simulated sunlight with a light amount of 100 mW / cm ² is irradiated to open voltage (hereinafter abbreviated as “Voc”). ), Short circuit current density (hereinafter abbreviated as “Jsc”), form factor (hereinafter abbreviated as “FF”), and photoelectric conversion efficiency.
About each measured value of "Voc", "Jsc", "FF", and a photoelectric conversion efficiency, it represents that a larger value is preferable as a performance of a photovoltaic cell.

3: Evaluation as a separator for a polymer electrolyte fuel cell Further, after forming an intermediate layer by the method described in Example 7 and Reference Example 1, a gas flow path is formed by pressing and a polypyrrole film is formed. The separator was manufactured. A cell was assembled using a solid electrolyte membrane carrying a catalyst on both electrodes, a gas diffusion electrode, and the separator described above, and power generation was performed using high-purity hydrogen gas and air as fuel, and IV characteristics were examined. Subsequently, the results of examining the IV characteristics in the same manner after the continuous power generation test for 1000 hours is shown in FIG.

  According to the results of Table 1, each of the corrosion-resistant conductive coating materials according to the present invention can obtain higher current efficiency than the Pt electrode obtained by the firing method conventionally used in the organic electrolytic oxidation reaction. It was recognized as excellent. Further, in Reference Example 2 and Comparative Example 3 performed in the same manner, it was confirmed that the π-conjugated conductive polymer dropped out during the electrolytic oxidation reaction and did not function as an electrode during electrolysis.

  According to Table 2, it was found that each corrosion-resistant conductive coating material according to the present invention can have a longer life than the Pt electrode obtained by the firing method conventionally used in the organic electrolytic oxidation reaction and is excellent in durability. . Furthermore, in Comparative Example 1 performed in the same manner, the intermediate layer was not provided to act as an electrode, so that an insulating oxide film layer was gradually formed, so that the electrolysis voltage increased and reached 10 V, and the electrode life was reached. It was. In Comparative Example 2, since the metal intermediate layer was provided without performing the heat treatment, distortion occurred due to the crystal structure gradually changing from the metal intermediate layer to the conductive metal oxide, and finally the intermediate layer and π The conjugated conductive polymer film fell off the substrate and the electrode life was reached. In Reference Example 1, the dopant in the π-conjugated conductive polymer film was destroyed by the oxidizing atmosphere, and the conductivity of the π-conjugated conductive polymer disappeared during electrolysis, resulting in an electrode life. .

  According to the results in Table 3, each conductive and corrosion-resistant coating material according to the present invention protects the substrate without any change even after 30 days of immersion test, and has excellent corrosion resistance characteristics required for dye-sensitized solar cell applications. It was recognized that On the other hand, in Comparative Example 1 and Comparative Example 2 in which the immersion test was similarly performed, it was found that the function of protecting the substrate from the corrosive environment was inferior because no intermediate layer was formed by heat treatment. In Reference Example 1, it was found that the π-conjugated conductive polymer film was destroyed because the dopant in the π-conjugated conductive polymer film was poor in oxidation resistance. In Reference Example 2, since the formation method of the π-conjugated conductive polymer film was not appropriate, the corrosion of the intermediate layer and the substrate progressed due to the penetration of iodine. In Reference Examples 3 and 4, it was found that since the formation temperature of the intermediate layer was low, the crystallization of the platinum group oxide was not promoted and the function of protecting the substrate from the corrosive environment was inferior. In Comparative Example 3, the π-conjugated conductive polymer film is porous, and the dopant in the π-conjugated conductive polymer film is easy to dedope in the electrolyte solution, and the carbon paste used for the conductive intermediate layer Since the layer was destroyed by iodine in the electrolyte, the result was the most advanced corrosion of the substrate. In the case of a baked platinum electrode, iodine in the electrolyte gradually permeates from the pin pole and crack, and the substrate Ti is corroded. After the 30-day test is completed, the thickness of the Pt layer becomes 0.5 μm and Pt is dissolved. I understood.

According to the results of Table 4, each conductive and corrosion-resistant coating material according to the present invention protects the substrate without any change even after 30 days of immersion test, and is excellent in the conductive properties necessary for dye-sensitized solar cell applications. It was recognized that On the other hand, in Comparative Example 1 in which the immersion test was similarly performed, the initial surface resistance was high because the intermediate layer was not formed, and the surface resistance tended to gradually increase as the immersion time increased. In Comparative Example 2, since the adhesion between the Ir plating layer, which is an intermediate layer, and the substrate is poor, the intermediate layer peels off as the immersion time becomes longer, microcracks occur in the conductive polymer film, and the surface resistance is high. The tendency to become was seen.
In Reference Example 1, since the dopant in the π-conjugated conductive polymer film was inferior in oxidation resistance, the π-conjugated conductive polymer film was destroyed and the surface resistance was very high. In Reference Example 2, the π-conjugated conductive polymer film gradually dropped out, and the corrosion of the intermediate layer and the substrate progressed due to the infiltration of iodine, and the surface resistance increased. In Reference Examples 3 and 4, since the formation temperature of the intermediate layer was low, the conductive path was not formed and the initial surface resistance was very high. In Comparative Example 3, since the resistance of the carbon paste layer was high, the initial resistance was high, and as a result, the surface resistance rapidly increased as iodine entered.

  According to the result of Table 5, it was recognized that the corrosion-resistant conductive coating material in the present invention can maintain good solar cell characteristics even 30 days after the immersion test. On the other hand, in Reference Example 2 in which the immersion test was conducted in the same manner, the π-conjugated conductive polymer film was peeled off from the metal substrate with the lapse of the immersion time, and the dissolution of the intermediate layer and the metal substrate started. It was confirmed that power generation was impossible due to a short circuit due to the contact of.

According to FIG. 1, the IV characteristic curve of Example 7 showed good power generation characteristics. However, in Comparative Example 3, the resistance of the corrosion-resistant conductive coating material was higher than that of Example 7, and thus the current density that could be taken out was high. I found it smaller.
Moreover, when the IV characteristic curves after carrying out the continuous power generation test for 1000 hours were compared, almost no deterioration in performance was seen in Example 7, and the current collecting performance of the corrosion-resistant conductive coating material was maintained and excellent. The power generation characteristics were confirmed. On the other hand, in Comparative Example 3, the corrosion resistance of the aluminum substrate of the conductive coating material was corroded to increase the resistance, and the dissolved metal ions adversely affected the proton conductive electrolyte membrane, resulting in a decrease in IV characteristics. As a result, the corrosion-resistant conductive coating material was inferior.

  The corrosion-resistant conductive coating material of the present invention is mainly used for electrodes for organic electrolytic synthesis, electrodes for dye-sensitized solar cells, and metal separators for fuel cells, but can be suitably used for electrical contacts and terminals.

It is a figure which shows the battery characteristic (IV characteristic curve) of the single cell using the separator manufactured according to the preparation method of Example 7 and Comparative Example 3. FIG.

Claims (10)

  A corrosion-resistant conductive coating material, characterized in that an intermediate layer comprising a platinum group metal layer and / or an oxide layer thereof is formed on a substrate, and a π-conjugated conductive polymer layer is formed thereon.   The corrosion-resistant conductive coating material according to claim 1, wherein the substrate is at least one metal substrate selected from the group consisting of titanium, zirconium, niobium, tantalum, aluminum, and iron and / or an alloy thereof.   The intermediate layer composed of the platinum group metal layer and / or its oxide layer contains at least one platinum group metal selected from the group consisting of iridium, ruthenium, rhodium, palladium and platinum and / or its oxide. The corrosion-resistant conductive coating material according to claim 1 or 2. The platinum group metal layer and / or its oxide layer is
A platinum group metal layer and / or an oxide layer thereof formed by applying, drying and firing a coating solution comprising an alcohol solution of a platinum group metal organic compound. The corrosion-resistant conductive coating material described.   The π-conjugated conductive polymer layer is at least one selected from the group consisting of polypyrrole or a derivative thereof, polyaniline or a derivative thereof, polythiophene or a derivative thereof. The corrosion-resistant conductive coating material described.   6. The corrosion-resistant conductive coating material according to claim 1, wherein the use is an electrode for electrolysis.   The corrosion-resistant conductive coating material according to any one of claims 1 to 5, wherein the use is an electrode for a dye-sensitized solar cell.   The corrosion-resistant conductive coating material according to any one of claims 1 to 5, wherein the use is a fuel cell separator.   A step of applying a coating solution comprising an alcohol solution of a platinum group metal organic compound on a substrate, drying and baking to form a platinum group metal layer and / or an oxide layer thereof, and then a π-conjugated system on the layer A method for producing a corrosion-resistant conductive coating material comprising polymerizing a conductive polymer monomer and forming a π-conjugated conductive polymer layer on the platinum group metal layer and / or its oxide layer .   The method for producing a corrosion-resistant conductive coating material according to claim 9, wherein the firing step is a firing step by heat treatment at 350 ° C. or higher.

Images