JPH01208489A - Catalytic electrode and production thereof - Google Patents

Abstract

PURPOSE:To suppress the contamination of an electrode and a plating soln. and to obtain an electrode having a catalytic metal layer only on the selected face by successively subjecting the desired face of a porous base material to electrolysis and electroless plating with the plating soln. to form a prescribed metal layer. CONSTITUTION:An electroless plating soln. for forming a plating layer of one or more kinds of catalytic metals for an electrode selected among Pt, Pd, Rh, Ru and Ir is prepd. The selected face of a porous base material is successively subjected to electrolysis and electroless plating with the plating soln. to form a layer of such catalytic metals.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a catalytic electrode and a method for manufacturing the same, and more specifically, the present invention relates to a catalytic electrode and a method for manufacturing the same, and more particularly, to the production of hydrogen, oxygen, or ozone by a water electrolysis method using a solid polymer electrolyte (for example, an ion exchange membrane). The present invention relates to a catalytic electrode suitable for zero-gap electrolysis, such as production of halogen by electrolysis of an aqueous halide solution.

2. Description of the Related Art Conventionally, in performing electrolytic synthesis such as water electrolysis and halide electrolysis, so-called zero-gap electrolysis has been carried out, in which an ion exchange membrane and a catalyst electrode are brought into close contact with each other.

The anodes used in this case are usually punched plates, expanded plates, etc. made of valve metal such as titanium or tantalum.
A porous plate such as a mesh, a photo-etched plate, a sintered plate of spherical metal fine powder or a fibrous metal is used as the base material, and a metal or metal oxide having an electrode catalytic ability is applied to this by electroplating, chemical plating, pyrolysis plating, or ion plating. A porous catalytic electrode is used, which is entirely coated by a method such as brating, and a porous catalytic electrode, which is a carbon powder whose surface is coated with an electrode catalyst by a method such as sputtering, and molded with PTFE resin, is used for the cathode. has been done.

Problems to be Solved by the Invention The reaction interface that operates in zero-gap electrolysis is the point of contact between the ion exchange membrane and the electrode. Therefore, in the conventional porous catalyst electrode, an electrode catalyst that does not participate in the electrode reaction is bonded inside the pores or on the back side of the electrode. Electrode catalysts present in such pores or on the back side may cause side reactions such as decomposing reaction products and reducing current efficiency. Therefore, in the porous catalyst electrode used for zero-gap electrolysis, it is ideal that the catalyst metal exists in the minimum necessary amount on the contact surface with the ion exchange membrane. However, according to conventionally known wet or dry plating methods,
Since it is difficult to prevent the catalyst metal from flowing into the pores or to the back side, and it is difficult to bond the electrode catalyst to the selected surface of the electrode, it is necessary to manufacture a porous electrode with the ideal structure as described above. I can't.

Means for Solving the Problems In view of the above-mentioned problems of the prior art, the inventor of the present invention has conducted extensive research, and has developed a method of stacking and sintering titanium materials that have been previously coated with platinum and untreated titanium materials. discovered that ozone, etc., could be produced at high concentrations when a lead dioxide electrode produced by electrodepositing lead dioxide only on the platinum coating layer was used for zero-gap electrolysis, and filed a patent application earlier. 62-7276
No. 2).

Furthermore, as a result of conducting research to obtain a catalyst electrode with excellent catalytic properties, the present inventor discovered that prior to electroless plating of a metal having electrocatalytic ability (hereinafter referred to as catalytic metal) on a porous substrate material, the substrate was coated with a cathode. and electrolytically treating a selected surface of the substrate using an electroless plating bath of the catalytic metal,
When electroless plating is then performed, a catalytic electrode is obtained in which the catalytic metal is bonded only to the selected surface of the substrate, and other parts, such as the inside of the pores and the back side, are not plated. They discovered this and completed the present invention.

That is, the present invention relates to the following catalytic electrodes and their manufacturing methods.

(2) A catalyst electrode comprising a metal layer having an electrocatalytic ability of one or more selected from platinum, palladium, rhodium, ruthenium and iridium on a selected surface of a porous base material.

■ Selection of the substrate when forming a metal layer having an electrocatalytic ability of one or more selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of the porous substrate material by plating. 1. A method for producing a catalytic electrode, which comprises electrolytically treating the treated surface using an electroless plating solution, and then performing electroless plating using an electroless plating bath having the same composition to form the metal layer.

■A metal layer having an electrocatalytic ability of one or more types selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of the porous substrate material, and a layer of lead dioxide or A catalytic electrode comprising a metal oxide layer having electrocatalytic ability, which is manganese dioxide.

■A metal layer having one or more types of electrode catalytic ability selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of the porous base material, and lead dioxide or manganese dioxide on the metal layer. In forming a metal oxide layer having an electrocatalytic ability by plating, a selected surface of the substrate is electrolytically treated using an electroless plating solution, and then an electroless plating bath of the same composition is used. A method for producing a catalyst electrode, comprising forming the metal layer by electroless plating, and further electrodepositing the metal oxide.

In the present invention, any known material can be used as the porous substrate material, but when using the obtained catalyst electrode as an anode, for example, an expanded plate of a corrosion-resistant metal such as titanium or tantalum, a photoetched plate, etc. A laminated material of perforated plates, a porous sintered body suitable for zero-cap electrolysis, etc. can be particularly preferably used. The raw material for the porous sintered body is not particularly limited and known materials can be used, but for example,
Spherical metal powders, fibrous metals, etc. manufactured by known methods such as a melt spray method, a rotating electrode method, and a crack vibration cutting method can be mentioned. Sintering is usually carried out in vacuum or in an inert gas such as argon or helium. Further, the sintering conditions may be appropriately selected depending on the type of metal used. Among the sintered bodies, the porosity is usually about 40 to 80%, preferably about 50 to 70%, and the opening diameter is usually 10 to 10%.
Particularly preferably used is one having a diameter of about 00 μm, preferably about 50 to 500 μm. When the porosity is less than 40% or the opening diameter is less than 10 μm, it tends to be difficult to replenish the electrolyte to the ion exchange membrane and desorb gas during electrolysis. Furthermore, if the porosity exceeds 80% or the pore diameter exceeds 1000 μm, there will be fewer contact points between the membrane and the electrode, and the current density will increase, potentially causing damage to the membrane.

When the resulting catalyst electrode is used as a cathode, known carbon-based materials can be preferably used as the porous substrate material. Specific examples include powdery carbon,
Sintered bodies such as carbon fiber chops, carbon paper, felt, cloth, and other carbon powder suitable for zero-gap electrolysis molded with PTFE resin
No. 276987), a sintered body containing expanded graphite (Unexamined Japanese Patent Publication No. 6
2-227098).

The opening diameter and porosity of the porous carbon substrate are not particularly limited, but are usually about 1 to 10 μm and 40 to 60%, respectively.
It is sufficient to set the degree.

Further, as the metal having an electrode catalytic ability, one or more metals selected from platinum, -palladium, rhodium, ruthenium, and iridium are used. For alloys,
The blending ratio is not particularly limited and may be selected as appropriate. Any known electroless plating bath for the above metals can be used. For example, a bath solution containing salts of the above metals, reducing agents, etc. may be mixed with ammonia water, alkaline pH buffer, etc. to pH 10 to 13.
Examples include electroless plating baths that have been adjusted to a certain degree.

Platinum salts include platinum nitro complex salts, platinum nitroammine complex salts, etc.; palladium salts include palladium nitro complex salts, palladium ammine complex salts, etc.; rhodium salts include rhodium ammine complex salts, etc., and ruthenium salts include ruthenium complex salts, etc. Examples of the iridium salt include nitrosylammine complex salts and iridium halides, but the present invention is not limited to these. Known reducing agents can be used, such as hydrazine, alkylamine borane, and the like. As hydrazine, its hydrate, hydrochloride, sulfate, etc. can be suitably used. For example, a reaction accelerator such as a hydroxylamine salt may be used as other additives in the electroless plating bath.

As the hydroxylamine salt, hydrochloride, sulfate, nitrate, etc. can be suitably used. The amount of the bath components added is not particularly limited and may be selected as appropriate. The above electroless plating bath is disclosed in Japanese Patent Publication No. 59-33667 and Japanese Patent Publication No. 59-39504.
No., JP 59-34784, JP 60-1627
It is described in No. 80, etc.

The catalytic electrode of the present invention described in (1) above is manufactured as follows.

First, a selected surface of the porous substrate material is electrolytically treated using an electroless plating solution for a catalytic metal.

Electrolytic treatment conditions are not particularly limited and can be selected as appropriate.

Usually, at room temperature, voltage is about 3.5 to 15.5V, and current density is about 0.05 to 1. Electrolysis is performed at approximately OA/dm2. In addition, before subjecting the porous substrate material to the above electrolytic treatment,
It may be subjected to cleaning treatment, etching treatment, pickling, etc. according to conventional methods.

Although the electrolytic treatment method is not particularly limited, a diaphragm method is usually used. An example of an apparatus for performing the diaphragm method is shown in FIG. In FIG. 1, (1) is a porous substrate (which becomes a cathode), and (3) is an anode. As the anode (3), a platinum mesh or a platinum-plated porous titanium plate is usually used.

The diaphragm (5) is required to have water retention properties that allow it to separate the cathode and anode and to supply catalytic metal ions to the surface of the cathode at an appropriate rate. If the amount of water retained is large, the electrolytic solution will enter the thin tube of the porous electrode and the inside will be plated, and if the amount of water retained is small, the electrolytic voltage will become high and heat will be generated, which is not preferable. Any material that satisfies the above conditions can be used as the material for the diaphragm (5),
Specific examples thereof include water-absorbing materials such as cellulose fibers and synthetic fibers used in filter paper, cloth, etc., water-absorbing resins, and cation exchange membranes. When a cation exchange membrane is used, the cationic metal ions in the electrolyte move through the membrane and are replenished to the cathode surface, so that the porous substrate (1) can be electrolytically treated more effectively. (7) is a titanium container that serves both as an electrolyte reservoir and a power supply material.

(9) is a metal plate that serves as both a weight and a power supply for press-contacting the porous substrate (1) to the diaphragm (5), and may be made of, for example, stainless steel.

The electrolysis is carried out by applying a diaphragm (5) on selected faces of the porous substrate (1).
), put the electroless plating solution in (7), and remove the diaphragm (
5) is carried out while maintaining the water absorption state. The thickness of the catalytic metal film deposited on the cathode (1) is not particularly limited;
．． It may be about 0.05 to 1.0 μm, usually 0.1 μm.
Around m is sufficient.

The electrolytic treatment using the diaphragm method described above can be particularly preferably employed when producing a large-sized catalyst electrode. In the case of small-sized electrodes, brush plating or similar methods can also be used.

By the above electrolytic treatment, active sites are selectively formed on one side of the porous substrate.

The porous substrate thus electrolytically treated is then subjected to electroless plating. Electroless plating is performed under normal conditions. Electroless plating starts when the catalytic metal surface deposited in the previous electrolytic treatment becomes an active site and grows by autocatalytic action. Therefore, plating does not occur inside the pores or on the back side of the porous substrate where the catalyst metal is not deposited, and only the necessary surfaces are selectively plated. By this electroless plating, the catalyst metal layer is usually 0.5 to 5.0μ
It is grown to about m, preferably about 1.0 to 3.0 μm. The amount of metal to be plated may be adjusted in advance by adjusting the amount of metal in the bath liquid. The metal utilization rate of plating performed in batch processing is about 90 to 95%.

In this way, the catalyst electrode of the present invention can be obtained.

Note that, if necessary, the electrode after plating may be cleaned according to a conventional method. Examples of the cleaning method include a method of suctioning with warm water.

In the present invention, a metal oxide having electrocatalytic ability may be electrodeposited on the catalytic metal plating film applied by the above method. As the metal oxide, lead dioxide or manganese dioxide can be used.

Electrodeposition can be performed according to known methods.

For example, after depositing platinum on a porous substrate in the previous electroless treatment, platinum can be deposited by electrolyzing using a lead or manganese electrolytic plating bath, using the porous substrate as an anode and stainless steel as a cathode. A catalytic electrode in which lead dioxide or manganese dioxide is selectively deposited on the layer can be obtained. Although the electrolysis conditions are not particularly limited, it is generally sufficient to carry out the electrolysis at a temperature of about 60 to 70°C and a power of about 3 to 5 A/dm2. Any known lead or manganese electrolytic plating bath can be used, and specific examples include a lead copper nitrate bath, a lead nitrate bath, a manganese nitrate bath, and the like.

In this way, it is possible to obtain a catalytic electrode having a catalytic metal layer and a catalytic metal oxide layer on selected surfaces of the porous substrate.

When performing zero-cap electrolysis using the catalyst electrode of the present invention manufactured by the above method, an ion exchange membrane-catalyst electrode assembly may be prepared according to a known method, or an ion exchange membrane and catalyst electrode may be combined. Zero-cap electrolysis may be performed by simply press-welding the two.

Conditions such as voltage at that time may be selected as appropriate.

Effects of the Invention According to the present invention, the following remarkable effects are achieved.

(1) A catalytic electrode having a catalytic metal layer only on selected surfaces of a porous substrate can be manufactured very easily. When this electrode is used for zero-cap electrolysis, there are almost no disadvantageous side reactions such as decomposition of reaction products and reduction in current efficiency, and it can be used as a very useful electrode.

(2) Catalytic electrodes of desired shapes, from large to small, can be easily produced.

(3) Since an electroless plating bath with the same composition is always used in the production of the catalyst electrode, there is no contamination or damage to the electrode, and there is no contamination of the plating bath.

(4) Since the catalyst metal can be deposited only on selected surfaces of the porous substrate, the amount of expensive catalyst metal used can be efficiently reduced.

(5) Carbonaceous materials can also be partially plated in the same way as metal porous substrates.

(6) The catalyst electrode of the present invention can be manufactured at a cost of about 1/3 to 115 that of the lead dioxide electrode for which the present inventor previously applied for a patent.

EXAMPLES Examples and comparative examples are given below to make the present invention even clearer.

Reference example 1 (manufacture of porous substrate) Chattering cut fiber (fiber length 2 to 3 mm, diameter approximately 60μ
A porous titanium plate having a diameter of 85 mm and a thickness of 3 mm (porosity: about 60%, manufactured by Tokyo Steel Corporation) was used, which was vacuum sintered from the above material. This titanium plate was placed in water containing 50 g of oxalic acid 500 times, heated to 60°C to etch the surface for 5 minutes, and then thoroughly washed with water while being suctioned.

Example 1 (Platinum plating) Porous titanium plate (cathode) obtained in Reference Example 1, porous titanium plate fully electroplated with platinum (diameter 85 m)
3 m, thickness 3 a 1 ms anode) and #4 filter paper (diaphragm, manufactured by Toyo Roshi ■) were arranged as shown in Fig. 1, and electroless plating bath with the following composition was applied to the extent that the filter paper was wetted, at 4 to 5 V. 0
．． Electrolysis was carried out at 3 to 0.5 A for about 10 minutes. After electrolysis, the porous titanium plate serving as the cathode was taken out and immersed in an electroless plating bath having the composition shown below to perform electroless plating at 65 to 70°C for 2 hours.

After plating, the porous titanium plate was taken out of the bath solution, washed with water under suction, and dried at 100°C.

Approximately 3μ is applied to a 0.5mm thick layer on one side of the porous titanium plate.
A catalyst electrode of the present invention was obtained which was plated with m platinum.

(Electroless plating bath) Tetraammineplatinum(II) chloride solution 300mg (P
28% ammonia water 2m05% hydroxylamine hydrochloride solution 0m12 20% hydrazine hydrate solution 8m (2 water
remaining needle
300 mQ Example 2 (Rhodium plating) The porous titanium plate obtained in Reference Example 1 was treated in the same manner as in Example 1, except that the following composition was used as an electroless plating bath, and the porous titanium plate was Approximately 0.5m on one side
A catalyst electrode of the present invention was obtained, in which a m-thick layer was plated with about 3 μm of rhodium.

(Electroless plating bath) Hexaammine rhodium chloride aqueous solution 300 mg (as Ph) 28% ammonia water 10-5% hydroxylamine hydrochloride solution 01TIQ 20% hydrazine hydrate solution 10 precepts
remaining needle
300 mQ Example 3 Spherical titanium (diameter 300 mQ) obtained by rotating electrode method (REP)
μm) obtained by vacuum sintering with a diameter of 5 InIfi and a thickness of 5
[QIll's porous titanium plate [porosity 40%, manufactured by Tokyo Type W4■] was etched and washed with water in the same manner as in Reference Example 1, and then treated in the same manner as in Example 1. A catalytic electrode of the present invention was obtained in which a .5 mm thick layer was plated with platinum to a thickness of about 3 μm. The basic operation is the same as in Example 1.
It is similar to

Example 4 Porous titanium plate obtained in the same manner as Example 3 (diameter 8
0mm, thickness 5mm) using an electroless plating bath with the following composition at room temperature, 5V, 0.5A, about 5 minutes), followed by electroless plating at 60°C for 2 hours) to form a porous titanium plate. A catalytic electrode of the present invention was obtained in which a 0.5 mm thick layer on one side was plated with palladium to a thickness of about 2 μm. Note that the basic operation is the same as in the first embodiment.

(Electroless plating bath) Potassium tetranitropalladate 200 mg (as Pd) 28% ammonia water 2 mQ 5% hydroxylamine hydrochloride solution 0 mQ 20% hydrazine hydrate solution 10-Water
remaining needle
300-Example 5 (iridium plating) A porous titanium plate obtained in the same manner as Reference Example 1 was electrolytically plated at room temperature using an electroless plating bath having the following composition.
V, 0.5 A, about 5 minutes), continued electroless plating 85
℃, 2 hours), 0.5 mm on one side of the porous titanium plate.
A catalytic electrode of the present invention was obtained in which a thick layer of iridium plating was applied to about 1.5 μm. Note that the basic operation is the same as in the first embodiment.

(Electroless plating bath) Potassium hexachloroiridate (IV) 250mg
(as Ir) 5% hydroxylamine hydrochloride solution 0ml 20% hydrazine hydrate solution 8mQ water
Remaining total
200 Commandments Example 6 (Ruthenium plating) Porous titanium plate obtained in the same manner as Example 3 [diameter 8
0mm, thickness 5mm, porosity 40%, made in Tokyo 14
(manufactured by No. 11) was electrolytically plated using an electroless plating bath with the following composition at room temperature, 5 V, 0.2 to 0.5 A, about 10 minutes), then electroless plated at 60°C for 2 hours), and the porous A catalyst electrode of the present invention was obtained in which a 0.5 mm thick layer on one side of a titanium plate was plated with about 1.5 μm of ruthenium. Note that the basic operation is the same as in the first embodiment.

(Electroless plating bath) Pentachlornitrosylruthenium potassium 200mg
(as Ru) Ammonia water (1:1) 10m22N
Sodium hydroxide 10-5% hydroxylamine hydrochloride solution mQ 20% hydrazine hydrate solution 1.
remaining needle
200 Commandments Example 7 (Lead dioxide plating) The platinum-plated porous titanium electrode of the present invention obtained by the method of Example 1 was used as an anode, the porous titanium plate whose entire surface was plated with platinum was used as a cathode, and a bath solution having the following composition was used. electrolytically (70°C, 3A/dm2, about 1 hour) on a platinum layer with a thickness of 0. A catalytic electrode of the present invention having a lead dioxide layer of 5 mm was obtained. No lead dioxide was deposited on areas other than those that had been previously plated with platinum.

(Electroplating bath) Lead nitrate (Pb (NO3) 23 1 mol/Q Copper nitrate (Cu (NOs) 2 ” 3H20) 0.1 mol/Q Water Balance needle
IQ Example 8 (Carbon electrode) Porous carbon plate manufactured by sintering expanded graphite [diameter 85
mm, thickness 0. 5 mm (manufactured by Kobe Steel, Ltd.)] was washed with acetone and water while suctioning. Use this as a diaphragm with a diameter of 9
A 0 mm cation exchange membrane (Nafion 117 membrane, manufactured by DuPont) was used, and the electrolysis conditions were room temperature, 4 V, 0.5 A,
The same procedure as in Example 1 was carried out except that the time was 2 hours, to obtain a catalyst electrode of the present invention in which a layer of about 0.2 mm on one side of a base carbon plate was plated with platinum to a thickness of about 3 μm.

Example 1 (Production of hydrogen and oxygen by water electrolysis) Hydrogen and oxygen were produced by water electrolysis using the electrolysis apparatus shown in FIG. In Figure 2, (11) is an ion exchange membrane, (13) is a porous catalyst electrode (anode), (15) is a porous catalyst electrode (cathode), (17) is an anode end plate, (1
9) is a cathode side end plate, (21) is a gas separator, (23) is an anode generated gas, and (25) is a cathode generated gas.

The electrolysis conditions and results are as follows. Zero-cap electrolysis was performed by directly pressing the membrane and electrode into contact without producing a membrane-catalyst electrode assembly used in the conventional SPE method (solid polymer electrolyte method). As shown below, the voltage is about 0.3 to 0.5 V higher than the SPE method, but the initial cost is 20 V.
Hydrogen and oxygen were obtained with good current efficiency and a reduction of ~30%.

Anode - platinum-plated porous titanium electrode (Example 1, diameter 8
5 mm, thickness 3.0 mm) Cathode: Platinum-plated porous carbon electrode (Example 8, diameter 85
mm, thickness 0.5 mm) 'Diaphragm: Cation exchange membrane (
(Nafion 117 membrane, manufactured by DuPont) Anode side end plate: Titanium material Cathode side end plate: Stainless steel material Temperature: 50 to 60°C Electrode liquid: Water current: 50A Current density: 100 A/di2 Voltage = 2 Voltage-2 , 2v Current efficiency of hydrogen generation: 99.5% Experimental Example 2 (Production of chlorine by hydrochloric acid electrolysis) Chlorine was produced by chlorine electrolysis using the electrolysis apparatus shown in FIG.

The electrolysis conditions and results are as follows. In this case, SP
Compared to method E, the initial cost was reduced by about 30 to 50%.

Anode: Iridium-plated porous titanium electrode (Example 5
, diameter 80 wms thickness 3.0 wm) Cathode: Platinum-plated porous carbon electrode (Example 8, diameter 80 flI111 thickness 0
．． 5non) Diaphragm: Nafion 117 membrane Anode side end plate and power supply body: Titanium material Cathode side end plate and power supply body: Impermeable carbon material Temperature = 30 to 40°C Electrode liquid = 7N Hydrochloric acid current 2 30A Current density: 60A/dm2 Voltage 1.7V Chlorine generation rate: 37.6 g/hour Chlorine generation current efficiency: 95% Experimental example 3 (Production of ozone by water electrolysis) Ozone was produced by water electrolysis using the electrolyzer shown in Figure 2. Ta.

The electrolysis conditions and results are as follows. In the SPE method,
In order to use it as a cathode, platinum must be bonded to the Nafion membrane, and the sintering process for the lead dioxide anode is required three times, whereas with the method of the present invention, electrode creation is completed in one time. Since the unbonded Nafion membrane can be used as is between the anode and cathode, the initial cost can be reduced to approximately 30 to 50 yen.
% reduction.

Anode: Lead dioxide coated porous titanium electrode (Example 7, diameter 80111111% thickness 3.0 mm) Cathode: Platinum plated porous carbon electrode (Example 8, diameter 80 mm, thickness 0.5
mm) Diaphragm: Nafion 117 membrane Anode side end plate and power supply body; Titanium material Cathode side end plate and power supply body Stainless steel material Temperature: 28
~30℃ Electrode solution: Water current: 50A Current density: 100 A/dm2 Voltage = 3 voltage - 3,5V Ozone generation amount: 2.50g/hour Ozone concentration: 18.0% by weight Ozone generation current efficiency: 18%

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an apparatus used in manufacturing the catalyst electrode of the present invention. FIG. 2 is a schematic diagram showing an example of an apparatus used when performing zero-cap electrolysis using the electrode of the present invention. (1) Porous substrate (3) Anode (5) Diaphragm (7) Titanium container (9) Metal plate (11) Ion exchange membrane (13 )... Porous catalyst electrode (anode) (15)...
・Porous catalyst electrode (cathode) (17)... Anode side end plate (19)... Cathode side end plate (21)... Gas separator (23)... Anode generated gas (25)...・Cathode generated gas (above) Purification of the drawing, I: (No changes/no changes to the content) Figure 1 Figure 2 Procedural amendment words and actions) 1 Indication of the incident Patent Application No. 33719 of 1988 2 Name of the invention Catalyst electrode and its manufacturing method 3 Relationship with the case of the person making the amendment Patent applicant Sasakura Kikai Seisakusho Co., Ltd. (and 1 other person) 4 Agent Sawanotsuru Building, 2-10 Hirano-cho, Higashi-ku, Osaka City May 31, 1988 6 Amendment Target drawing Surface 7 Contents of correction

Claims (4)

[Claims] (1) A catalytic electrode comprising a metal layer having an electrocatalytic ability of one or more selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of a porous base material. (2) A metal layer having one or more types of electrode catalytic ability selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of the porous base material,
When forming the metal layer by plating, electrolytically treat the selected surface of the substrate using an electroless plating solution, and then perform electroless plating using an electroless plating bath of the same composition to form the metal layer. A method for producing a catalytic electrode characterized by: (3) A metal layer having an electrocatalytic ability of one or more types selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of the porous substrate material, and a layer of carbon dioxide on the metal layer. A catalytic electrode comprising a metal oxide layer having electrocatalytic ability, which is lead or manganese dioxide. (4) A metal layer having an electrocatalytic ability of one or more types selected from platinum, palladium, rhodium, ruthenium, and iridium on a selected surface of the porous substrate material, and a layer of lead dioxide or When forming a metal oxide layer having electrocatalytic ability, which is manganese dioxide, by plating, a selected surface of the substrate is electrolytically treated using an electroless plating solution, and then an electroless plating bath of the same composition is applied. 1. A method for producing a catalytic electrode, comprising forming the metal layer by electroless plating using the metal oxide, and further electrodepositing the metal oxide.