JPS6092494A - Method for joining platinum or platinum alloy electrode to ion exchange membrane - Google Patents

Abstract

PURPOSE:To form a platinum plating film at a high speed by forming preliminarily a plating nucleus on the surface of an ion exchange membrane and subjecting said surface to electroplating with a plating liquid of a specific pH value contg. a platinum compd. and hydrazine which is a reducing agent. CONSTITUTION:A platinum or platinum alloy electrode is joined to an ion exchange membrane by an electroless plating method to improve the performance of an electrochemical device with which the ion exchange membrane is used as an electrolyte. The plating nucleus of a platinum group metal is formed by a sensitizing treatment on one or both surfaces of the ion exchange membrane for the above-mentioned purpose. Such ion exchange membrane 4 is fixed into resin frame bodies 1a, 1b. A plating liquid which contains a water soluble platinum compd. such as chloroplatinic acid, platinum amine complex, or the like, a water soluble compd. of other metals if necessary as well as hydrazine or the salt thereof as a reducing agent for said compd. and is adjusted to <5pH is supplied through inlets 7, 8 into chambers 5, 6 and the platinum or platinum alloy is electroless-plated at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the H method for bonding platinum or platinum base metal electrodes to ion exchange membranes, and its purpose is to bond ion exchange membranes and white metal electrodes using a new electroless plating method. Alternatively, the purpose is to provide contact with platinum alloy 'i[ffl.

Electrochemical FJ devices that use ion exchange membranes as a solyte include water electrolysis devices and halogenated alkali dissolution devices.

There are oxygen component #lI devices, hydrogen separation devices, fuel cells, etc.

In these various fK vaporization devices, there are cases in which the ion exchange membrane and the electrode are integrally joined and cases in which they are not used, and the present invention relates to the former case. Conventionally, methods for joining an ion exchange membrane and an lJc electrode include the #11E deplating method and the method of heating and adhering to a special model.

Furthermore, the electroless plating method can be classified as
Two chambers were created by separating the ion exchange @ described in No. 878, and gold salt mH was placed in one chamber, and the title agent water bath solution was permeated from the other chamber, and the membrane surface on the metal salt RD liquid side was The metal is precipitated by a method usually called the penetration method, and the surface of the plating is roughened and the palladium, which becomes the core of the plating, is treated with platinum, which is then mixed with gold and salt. There is a method called chemical plating, which has been conventionally used for plating of moss and the like, in which the plate is immersed in a mixed layer liquid with a chemical agent and plated. Compared to the electroless I++'l plating method, the heating l:lE blue method has the advantage of being able to bond materials other than metallic composites, such as oxides, as a @ medium, but it is difficult to prepare the electrolyte layer. However, it is difficult to compare if the water electrolyzer is
In this case, the disadvantage is that the field 6 stroke is shorter than the front position.

On the other hand, the non-exploding plating method has a comparative cleavage rate of 1Ffi + 1t compared to the heating method, and it is possible to use flow-tightness in most cases, but among them, the chemical plating method Compared to the infiltration method, there is an advantage that the joint strength of the joint is stronger with less - [y . .

However, in the chemical plating method, careful attention is required in the preparation and management of a plating bath using a mixture of gold MsrM and 1) shading.

Generally, in order to increase the plating speed, a strong quaternary agent is used and the plating bath is warmed up. However, the more this is done, the more unstable the plating bath becomes, and eventually the self-decomposition of the agate bath results in the precipitation of plating particles in the plating bath. You can do the above operation and the reverse operation, but if you do that, the rate of 1st success will be delayed.In this way, increasing the plating fA resistance and ensuring the safety of the metal foil bath. There is often a trade-off between what we do.

The pieces of this invention have been diligently researched, and as a result, the above-mentioned discovery has been made.
Recalling that plating is performed in a range where the pH of the metal bath is 5 or higher, the present invention was achieved. That is, the present invention completely solves the conventional problems by adjusting the PR of the plating bath to 5 or less, and
To provide a plating method that does not cause any self-decomposition even when left at a temperature of 80°C for a long time and has a sufficiently high plating rate even at room temperature.

The following describes a method for coating platinum and platinum alloys on an ion exchange membrane using the plating bath of the present invention. Book! g
Akatsume Iki and Tani are human'radin or hydraciso compounds as reducing agents, chloroplatinic acid as platinum CfkjT1, platinum iodide, white oil anomine complex blocks, and other platinum compounds I+! ! It consists of a compound II and has a pH adjusted to 5 or less. When plating one base alloy, a desired metal salt may be added thereto.

Hydrazine and hydrazine compounds are used as reducing agents because they self-decompose and exhibit strong reducing power. The platinated fraction is very easily reduced, and when mixed with hydrazine, it is reduced to one echo. Therefore, when preparing a medium plating bath using hydrazine as the head 1111, it is preferable to first add an acid to hydrazine 7 to make Pli 5 or less, and then add a platinum salt to this. Furthermore, when finishing adding salt, the pH of the bath is
Adjust as necessary so that the hydrazine does not exceed 5. If an acidic hydrazine compound such as sulfuric acid hydrazine is used for hydrochloric acid hydrazine, platinum 11.A should be added to these aqueous solutions. You can adjust the Ph after adding
One plating bath prepared in this way was 8゜”ρbr ((l
) f2, U:″, :P-n self, 1/isn, htΔ/+
-+-, u+, +-c tr We must perform an alpha principle called sizing, which attaches metals to metal nuclei.Part 1
A known method was used for fL, including 10 treatments of 6 cation exchange models, and ion exchange reaction of a platinum anomine complex to the substituent group. The most suitable method is to immerse the protective film in 160ml of sodium borohydride water to deposit a thin layer of platinum on the surface of the protective film. In this way, when carrying out [7゛C pre-treatment and immersing the γ-coated film 11K in the metallization bath according to the present invention, a metallization nucleus is formed in the pre-treatment and a cap is attached to one part. Or platinum alloy precipitates selectively.

Below, actual examples of the present invention will be described in detail.

+i'T diameter 12f1 silk ion exchange nuff r on 12
5 in the holder shown in Figure 1. Porter is made of acrylic resin frame (l&) and (ll))
lki'/ (211).

(2I), (21 and (2d)) are tightened with metal fittings (
3a-BfrXiRblPbhWtRVAfl,-
F Fio:) 19F1141 has a central part that retains its elasticity 3\
I1. r: Holter's 1st chamber A (51 and 1st chamber Bl + 6+ L + each injection 1:E
I71 and (8) to platinum 7゛/mine complex ((PtC
I2 (NIIR) 2) Cl21 water 1 injection 1 common solution
2.i.

Separation equipment 1 Kora practice 1 white α asomine complex water bath rll
After draining, wash thoroughly with water.

In this process, Nafion 125's SuJ
Refio/Ya's hydrogen iono and platinum ionomine
/Toga ion 111 exchange, is this 7J? 0.5% sodium borohydride 7
Immerse in Nafion 126 for 7tt in J II solution for 7tt. Target treatment: A') Add 1 q of ε complex 1, and precipitate platinum on both sides of Nafion 1250. n
Is nT the part where other parts are precipitated? The amount of precipitation is 0.81j on each side of 125.
One f/cd. In this book, CD is the sensitizing process, HP is 11, and then the chemical makeup process is started.

(Add 1 F of salt to 1.5 m++ l/e of hydrazine hydrochloride, 1 F of 6-water phase of platinic acid, and then add aqueous ammonia to adjust the pH to 4. Shi T Konafio'] 125 'e 70
'C for 70 minutes 1 ■ 4 soaks 1 bath. In this step, all the platinum in the make bath is cut out to the part where platinum was attached in the sensitizing step. The platinum precipitator that adds +3 cis to each song of this engineering IJ, dK Okero Nafion 125 is fl, 7AIN/c11, and in the end, each side of Nafion has 4.5 ri/c- day cutting. Mefuki is li
If you try to combine the method according to the present invention with the method of the I-ho-kama method, you will end up with the number one.
[Apply 4x4.5/C'-platinum polishing to II,
Comparing the appearance of the outer cut and the 1 hour it takes to make the kebatake, I got the results shown in the table below.

Are the Yusou Power Bows in the table above the same? The plating method also lowers the conventional pH to 8.
It is not possible to plate with the oxidation method, and it cannot be plated with the penetration method.
However, it is clear that the method of the present invention requires only one metal and the time required to manufacture the joined body is very short.

In the meantime, I made each of them in Au and assembled them in Au. child.

In the @2 cause, r, +91 is an ion exchanger, on one side of which is bonded an F'J medium electrode (lO) made of self, and on the other side is an anode 1 medium electrode (11) made of platinum. ing.

Yin Chewing Catalyst I “Wei (If Su and I Yi Garden Cheating Media Electric Spit (11)
Each has a yin (children's city structure (12J and 1 easy old woman))
C&M(1) is assigned. In addition, Yin Kite Jitun & Mt.
12) and vdIJ pole collection + Il [I3) are respectively i1
Titanium glue board ``One piece (14J) and one piece (14J)
(There is one in 15J.) Each of these electrolytic cell components is held in the frame (1G).
When water is supplied from the water supply port (17) provided in the tube element 67 and a 111 current DC is passed between the negative and positive image electrodes, the water is electrolyzed, oxygen is discharged from the tube element outlet (18), and hydrogen is generated. Hydrogen is discharged from Kawaguchi (19).

Figure 2 shows the results of the present invention at a current density of K I A / cd. Law (for N, 熥“
It can be seen that the position is very stiff, and the first shift is low and the performance is excellent.

In the case of the Bl permeation method, 'K I-E increases rapidly from the beginning of II!1, but this is because the bonding strength of platinum is weak and platinum is Think of it as a falling f-rice.

As described in detail above, the present invention improves the conventional method to provide a much superior contact between an ion exchange membrane and platinum or a base alloy and an electrode. The value is extremely high.

[Brief explanation of the drawing]

@ Figure 1 is a cross-sectional view of a holder for an ion exchange unit according to an embodiment of the present invention, Figure 2 is a schematic cross-sectional view of a water electrolysis tank according to an embodiment of the present invention, and Figure 3 is a schematic cross-sectional view of a water electrolysis tank according to an embodiment of the present invention. This figure shows the changes over time in the water-swelling aneurysms of actual cases in comparison with those obtained by conventional methods. ta, tb ・-・・・・ykrylic fat fissure body + 2
'+ 2J 2C+2d・・・Putskin+8L
Lad”...Tightening metal fittings. 4...Ion exchange model 15...Toden A,
6... Chamber 15.7... fIF, inlet A, 8... Inlet B. 9...Ion exchange reaction, 10...Yinzui medium awakening, 11...VA birch chewing medium surface, 12...
...Cathode φ vehicle length A. 13 ・・・・・・ mwei (stop the turtle, 14 ・・・
・・・・1 ship, 1 dock, 1 river. 15...Darkness 1 @ IJ! Awakening body, 16...
frame body. ■7...Water supply port, 1g...Oxygen outlet. 19...Hydrogen outlet. 5X1(!1 (V) )X 7 times/A O'3 prisonerz, tl Zf?

Claims (1)

[Claims] After forming a plating nucleus of white group e on one piece or both sides of the ion-exchange membrane to be a, a water-bathable metal such as 11 platinic acid or contains a mixture of the compound and other water-bathable metal compounds, and human 0-radine or a hydrazine salt, and has a pH of
A method of placing platinum or a platinum alloy on an ion exchange membrane, which is characterized by electroless plating of a base or a platinum alloy using water adjusted to 5 or less as a plating bath.