JPS59200781A - Electrode for electrolysis - Google Patents

Abstract

PURPOSE:To develop an electrode for electrolysis which is low in overvoltage on Cl and O2 by depositing a material to be deposited by consisting of a porous Pt metal on a corrosion resistant and conductive base body and depositing further an oxide of Ir, Mn, Co, etc. thereon at a specific rate. CONSTITUTION:A porous platinum metal is formed by electroplating on the surface of a metallic material such as Ti or the like having excellent resistance to corrosion to form a material to be deposited as an electrode for electrolysis which is used for electrolysis in an aq. acidic soln. contg. a sulfuric acid or a low concn. of chlorine ion and of which the overvoltage characteristic on Cl and O2 is of a low value. A soln. contg. >=1 kind among iridium oxide, manganese oxide and cobalt oxide when decomposed thermally is penetrated thoroughly in the platinum metal and is thermally decomposed in an oxidizing atmosphere to deposit said oxide. The electrode is formed by depositing the material to be deposited, which is the platinum metal, and at least 1 kind of manganese oxide and cobalt oxide of 1-60atom% in content of Mn and Co with respect to 40-99atom% iridium oxide in content of Ir on the base body.

Description

[Detailed Description of the Invention] Technological Classification> The disclosed technology can withstand oxygen generation environments such as electrolysis in sulfuric acid acidic solutions and low chlorine concentration solutions, and can withstand overvoltage against desired Ti electrode reactants. Belongs to the technical field of electrodes for low electrolysis.

Explanation of the gist> Therefore, the invention is based on a corrosion-resistant material such as titanium.
2;! An invention relating to an electrode for electrolysis in which a part or all of the surface of an integrated body is coated with a porous skin and a supported material is supported on the electrode reaction 1 wood - Yes, 1z1, a porous platinum metal supported material is integrally formed on the surface of the above-mentioned corrosion-resistant conductive substrate by an electrolytic method, etc., and then 40% is added to the surface of the corrosion-resistant conductive substrate by a pyrolysis method, etc. ~
99 atom% iridium oxide and this (as opposed to mankan,
and cobal 1 to 1 to 60 atomic % in content of ihimancan acid and cobal oxide 1 to 1). This invention relates to an electrode for electrolysis.

<Prior Art> As is well known, there is an electrode for electrolysis that is widely used in general, and includes an electrode reactant coated and bonded on a corrosion-resistant conductive substrate. In terms of basic characteristics, there are basically two conditions. Firstly, there is the bonding condition to the substrate as an external condition of the electrode reactant. It is necessary for the electrode reactant to have strong chemical corrosion resistance and, of course, to have electrical conductivity.Secondly, as for the internal conditions of the electrode reactant itself, the electrode reactant must be The mutual strength of the mechanical bond between the constituent components is strong, and the chemical corrosion resistance is strong.
Of course, it is desired that the electrode has a predetermined conductivity and, in addition, has a low overvoltage when the electrode reacts.

By the way, as for the above-mentioned ordinary electrolytic electrode in which an electrode reactant is coated and bonded on a corrosion-resistant conductive substrate, there have been many known electrolytic electrodes in which the electrode reactant has a composition containing a platinum group component. There is.

Therefore, there are two types of electrode reactants containing platinum group components: platinum consisting only of platinum group components, metals containing only platinum group components, and platinum group oxides. Electrolytic electrodes coated with platinum metal have been used for a long time, and many improvements have been made to those coated with platinum metal, such as bonding of the electrode reactant itself and bonding to the substrate. A good electrolytic electrode with high strength, excellent corrosion resistance, and durability has been developed.

However, although the electrolytic electrode coated with the seed platinum metal has many excellent properties as described above, it has the disadvantage that its applications are limited.

<Problems with the conventional technology> If we cover the problem and consider the major factors, compared to the electrodes used for various other practical applications, the problems with electrolytic electrodes using platinum metal as the electrode reactant are Although the overvoltage characteristics for smoked silver and oxygen are low at the initial stage of electrolysis, similar to Haku's electrode, they increase as the electrolysis time progresses and reach high values, resulting in an increase in electrolysis power consumption. This is because there is a disadvantage that the cost is high, and there is also a problem that an electrolytic reaction other than the intended purpose occurs due to the upper limit of the overvoltage, which may inhibit the intended purpose electrolysis.

To deal with this problem, several attempts have been made to solve the problem of overvoltage increasing with the passage of time in electrodes using platinum metal as an electrode reactant. Techniques have been developed to suppress the rise in overvoltage by adding and alloying metal by various means, and to reactivate platinum metal electrodes with increased overvoltage by using the cathode Iff.

However, it is difficult to manufacture electrodes using this interspecies optical technology in practice due to the complicated process.
, ll, 5111 points, resulting in an electrode with poor corrosion resistance, and disadvantages such as short duration of active effect, so it has not been put to practical use.

On the other hand 1. The former) The latter electrode reactant component contains a platinum group oxide consisting of rufnium oxide, rhodium oxide, palladium oxide, or iridium oxide, which is converted into a corrosive conductive group. The coated electrolysis electrode has low overvoltage, excellent durability, and stable catalytic function, and is made of platinum 1N812.
The typical manufacturing method for compound coated electrodes is the thermal decomposition method, in which a solution containing a compound that forms platinum group oxides through thermal decomposition is applied onto the gas surface. It has many advantages, such as the fact that even a combination of multiple components can be easily obtained.

However, if the electrode reactant is one type of platinum or an oxide, mechanical bonding of the electrode reactant to the substrate,
In addition, the primary mechanical bond strength of the electrode reactant itself is extremely small, which causes the electrode reactant to fall off during the electrode reaction.Furthermore, the life of the electrode is extremely short, making it impractical. There were some inconveniences.

Therefore, in order to increase the life of the 6-platinum group oxide FD-electrode, it has been necessary to add a corrosion-resistant oxide such as titanium oxide or a second component such as a platinum group metal to the platinum group oxide component. Increasing the bonding strength of electrode reactants has been attempted by taking measures such as mixing with these, alloying, or forming a mixed crystal.

On the other hand, non-platinum group oxides such as manganese oxide and cobalt oxide are also known as electrode reactant components.

However, from A, r]1 corrosive electrolyte! 4 (covered on the wood surface) 's7 electrolyte 0 reaction 1 H or non-platinum II χ acid IL
(In the component of J, the electric current is 41. The reaction Iho and the pair J.
! Because 4j < , A, the initial potential of the electrolytic anti-conductor 11k) is:! :! l < , it has not reached the point where it can be used practically 1.λ body surface with Nl resistance such as ditanium
2. An electrolytic electrode consisting of a porous V (supported material component inside the damaged object and a three-dimensionally supported Jf on the surface), that is, an electrode reactant component The electrode reactant is formed by dividing the supported object component which has been bonded to the object into two different independent component compositions, and the supported object component which is three-dimensionally bonded to the object. , Basically, 1! 11 E mechanical bonding 1. 6 prevents the electrode reactant from falling off, and chemical 1 ii
4 eclipses 1! In addition, he devised an electrode for electrolysis according to the invention and published a special publication on page 1.

Furthermore, the Ministry of Invention has proposed that in the electrode for electrolysis, the above-mentioned damaged material component is a porous platinum metal, and on the other hand, the above-mentioned material component is a combination of iridium oxide (a certain J, uniη), and a sulfuric acid acid solution. Nakaya) [(12,j left ion iF!
We have developed an electrolytic electrode 4~ that has low overvoltage and excellent durability for the desired electrode reaction in 711 solution in a solution,
A patent application was filed for this.

<Purpose of the Invention> The invention of this application not only solves the problems of the above-mentioned conventional electrolytic electrodes 4~, but also technically exists as an extension of general electrolytic electrodes. The technical problem is to further improve the above-mentioned support component b. By adding at least one type of electrolytic electrode, an electrolytic electrode with lower overvoltage and greater durability has been created, and this is an excellent electrolytic electrode that is one of the best in the field of electrode application in the chemical industry. Please provide the manufacturing method/υ.

<Structure of the Invention> In accordance with the above-mentioned purpose, 4. of the invention of this application is summarized in the scope of the preceding claims. +H or corrosion-resistant polymerization 1) After bonding platinum gold 171 with porous holes "C'i" on the surface of the body by electroplating etc. to form a material to be f(l l;'l), heat treatment is performed. By decomposition, iridium oxide, 6f-depleted mancan, and
A solution containing an iridium compound, a manganese compound, and at least one of the compounds 1-11 (1-11) was formed by bonding the solution as described above. The platinum metal in the damaged material is sufficiently penetrated into the platinum metal, and the oxide is supported on the platinum metal in three dimensions by thermal IW in an oxidizing atmosphere, so that the electrode reactant becomes porous. Supported material of platinum metal component and iridium content / 1 = 99 atomic % iridium oxide, manganese and cobal, 1 - content of manganese oxide of 1 to 60 atomic %, and cobal oxide 1 to 1 At least 111 of
・F's l! As the electrode for electrolysis is made of I:J material, the overcurrent 11 is reduced during operation of the metal, and the corrosion resistance is prevented from deteriorating. 'j ・We have taken technical measures to make it possible to control this.

<The origin of the invention (!l!>) Therefore, for the electrolytic use of the present invention, the -1-2 support is prepared by adding at least one weight of prescribed mancan oxide and cobal oxide to iridium C oxide as its component. In the electrode,
Since the true electrode area is smaller than in the case of an electrode for electrolysis with only iridium oxide as a support component, it is possible to maintain a lower overvoltage, and it is also possible to maintain a lower overvoltage. ! Since the numerical bond between the metal oxide, which is a J compound, and the platinum metal, which is a supported substance, is porous, the platinum gold jh; By supplementing the mechanical bonds of the metal oxide itself, the mechanical strength is improved (unruly).In addition, the support itself is active and forms a three-dimensional structure, which increases the mechanical strength during electrolysis. Preventing the inactivation of platinum and resembling the electrode potential < IIl,
In addition, in electrolysis in a solution with a low chlorine ion concentration, electrodes for chlorine generation of manganese oxide and cobalt oxide can be used. This is thought to be because the catalytic converter allows the overvoltage to be kept even lower.

Moreover, the state of the oxide is different from the X-ray diffraction results, and its rI
Lengthening! ll/l! The condition of body II is different from that of 4, and 18 children are born.
It was found that a number of nits were found, and that it was used in the form of a composite oxide. Therefore,” = Note I [! , irj material component component I) Iridium oxide fil was made to contain 1゛14, 10, 9, 17% (J, 7□
Sushi, 40 atomic % J, when lowered, it becomes manganese oxide with poor corrosion resistance.
, 4i (Because there is a large amount of wood precipitated in the carrier R+ material component, 1l14 erosion'1no [or low 1;4) occurs, and as a result, the electrode reaction I41 wears out faster. This is because there is a problem that the electrode life will be shortened, and if it exceeds 9 atomic %, an overcharge will occur in 1.-f Ill 1. '1 effect -12 is reduced and the effect of avoiding an increase in the true electrode area Jυ1 Takashi 51
The electrocatalyst used for cattle has a weaker effect on the geometrical surface, and its ability to reduce overvoltage is weak.

Therefore, the optimum iridium content is 40 to 99 at%, and as a result, at least one of mankan oxide and cobalt oxide can be used. As a relative result, the optimum content of mankan and cobalt is 1 to 60 at %.

By the way, next, regarding porous platinum metal as a material (J, to form this, there is a means to form porous platinum metal directly on the surface of the substrate, and platinum gold If4
One possible method is to perform a porous treatment after forming the J+ coating layer, but in the latter case, the surface of the platinum metal is roughened and a solution of the compound is completely permeated into the platinum metal to support the non-platinum group oxide in three dimensions. 1) Avoid the state of 1! There are times when it is not possible to do so.

Therefore, in order to form a porous platinum metal in the electrode for electrolysis of the present invention, it is desirable to adopt a method of forming a porous platinum metal through oxidation. In addition to the electroplating method mentioned above, there are thermal spraying methods, thermal decomposition methods, etc., but among these methods, especially (if (
Is it wrong and is it a sutra? What is convenient in terms of f'+ is the electroplating method mentioned above, in which a state in which the state of electronic platinum is formed by porous and spherical aggregates appears. It is desirable that the

In addition, platinum gold 17 is more porous, that is, it has a mechanical support strength of 1α! If K is 177; iJ, N,
After suitably forming the platinum metal in the i-contact porous hole, the porous i
ffi I that increases the 1 state! l! i・I “i”:
An effective method is to

In the manufacturing process, there is a supported object C in J3. To record 6x metal, as a chemical fj property (,
1 contains a compound of non-platinum H. It is necessary that all joints of platinum metal be in a state of 1Σ2 to prevent deterioration due to reactions of oxidizing gas or volatile components in compounds.

Therefore, in the method for manufacturing the '1b electrode for electrolysis (, L-bearing J
The porous platinum metal is a sufficient core of the solution containing the compound♀/cai! Is it only platinum metal to reduce j to 11J?
l: l] Or rather, the porous 'l'1 state is significantly increased, and as a result, if the density is less than 8g, 'Cm3, the mechanical strength will decrease (on the contrary). On the contrary, there is a risk that the life of the electrode may be lost.

In addition, when the oxide is three-dimensionally formed on the porous platinum metal object as a support, the thermally decomposed compound and its solvent penetrate into the platinum metal in the direction d'1. It is desirable that the viscosity of the solution is low and the moisture content of the compound is not too high.

As an auxiliary means for improving the penetration of the compound, it is also effective to irradiate the substrate with ultrasonic waves.

<Example> Next, a detailed explanation of this invention is summarized as follows.

<Example-1> A ditanium metal plate was degreased with 1 Helicane degreasing solution, and the surface was treated with hydrofluoric acid aqueous solution and Taki hydrochloric acid 1!1! After getting back to normal, Gini 1~Russiamino Platinum (lXj M water iff
1.t of Mika 1) was applied onto the surface of the titanium metal plate substrate by an electroplating method using a platinum plating bath dissolved in a liquid.

The degree is about 161J/cm3? l[Hanging is 1.7m g
A sample 4'81 was prepared in which porous platinum metal was formed as a JO-bearing substance of /am2.

On the other hand, 1.95 g of iridium chloride IX acid, in (0.20 g of
1:ll, i8d, ■2.1 iridium cup 195
(), 21 chloride (・ 0.33 s, 1 tanoyl 1 m
l, Tsuknor 19011's ('if if'2, and O
・Iridic acid oxide 19]) Mancan oxide 0.1
4. Kohar oxide 1-0.1! i, Q, L fural 1+
:i, Tsukunor 1 Onil iF''(1+) solutions were prepared respectively.

Therefore, each 4': Ifi? , 'F ii with j11 The suspension of metal oxide is Cli fti with metal
19> Take 0.14mg/cm2 of 0.14mg/cm2 into the mike mortar I as if 4f each, j111 platinum all platinum gold i surface, j3 each 'lj (b shi, then... (Dry cooking for 111.'J by vacuum drying method)
After heating at 500°C for 20 minutes (1 example electrodes -1, -2, -3 were heated to 1'1 - 1').
For comparison, Iridium chloride M 2.14
Dissolve g in 2 On+l of phthanol and infiltrate it.
, l; Same as 4'I: In the process, 1.7 mg/cm2 of platinum metal as a support is formed on the ditanium metal plate, and the suspension of iridium oxide, which is a support, is made of metal. 0.14 mg, '01112' after conversion (C).
',='G tM! Comparison electrode 14I-1 was prepared by drying, drying, and adding 11 times in the same manner as the culm.

Next, each of these electrodes was heated to 30 g/ρ of sodium chloride (10 Δ/dm' in one cell) in the liquid groove j 3Q"C.
The electrodes were washed with oil at 160°C in a sulfuric acid solution of I fvl /4 (10 min in 1 minute).
Measure the electrode type (1', +) to Δ/(lnl', and send the results to person-1.

From Table 1, it is found that Example electrode 1 is made of a mixture of iridium oxide and one or more of predetermined mankan oxide, O.
, -2 and -3 are comparison electrodes -1 with only iridium oxide supported? It is recognized that when it is hot, the electrode potential is sufficiently low, that is, the overcurrent If is low.

Implementation f! II+ -2> The above-mentioned actual M (in the case of Example-1, do the same! (4, titanium 6 and layer plate 1-)
To m-C"den\'jM is 1.7m/'C: II+
1.56 iJ of iridium chloride, 0.84 iJ of cobalt chloride, 2 ml of ethanol, 18 m of tutanol.
Using 1 volume of the solution in Example 1, proceed as in the case of preparing the electrode 4 in Example-1. ``Example electrode-4 was prepared by carrying 0.14 mg/cm2 of metal oxide on the above-mentioned supported platinum metal in an exchange case in which all the supporting metal oxides were metal. For comparison, platinum metal to be supported was formed on a ditanium metal plate using the same process as in the example, and then IEi
j j Hiviridium 1.24g, Kobal chloride 1-1.3
Using a solution of 4 g, 2 ml of fural and 18 ml of phthanol, the total weight of the metal oxide supported on the electrode of the above example was measured. 0.14mL, J/c+
++2 gold 1. 1 oxide to the platinum metal to be supported.
Dimensional! Comparative electrode-2 was prepared by holding the sample.

Next, the above-mentioned Example electrodes A-2 and -4 and the above-mentioned Comparative electrodes-1 and -2 were added to the IM solution at a liquid temperature of 55°C.
Electrolysis is carried out at a current density of 'r400△/cl m2,
Constant RB Kotoni'tl Flow density 1 A/d m”
d3 +j Z+ Electricity 41i Measure the iLj position, and the potential at A is 141 Fuhua 111211i i4+
Table 2 shows the electrode life until the potential reaches 1.7V.
J Show °.

[- From Table 2, the ratio of iridium oxide in the supported material is less than 40% with iridium content.] It is seen that the speed becomes faster and the electricity (Kunoi no Mikoto becomes wiser).

<Effects of the Invention> As described above, according to the present invention, in a Ti electrode for electrolysis in which the surface of a corrosion-resistant conductive substrate is coated with an electrode reactant, the porous material forming the framework of the ]j4 component of the electrode reaction component J.S., who supported the supported object three-dimensionally on the supported object.
Basically, it has excellent mechanical bonding strength (・*), prevents the electrode reaction pair from falling off, and has excellent chemical corrosion resistance.
This has the effect of lowering overvoltage during electrode reaction.

Further, a solution containing a set atomic percent of at least one compound among iridium oxide, mancan oxide, and at least one compound of cobal 1 to 1 among the compounds that become iridium oxide, mancan oxide, and dibalt oxide is permeated into the platinum metal. The electrode for electrolysis, which has been made to have a three-dimensional support of 10% by thermal decomposition, has a larger true electrode area due to the support component being iridium oxide (1), which lowers the overvoltage. In addition, during electrolysis in solutions with low chlorine ion concentration, such as power water, it is possible to further reduce overvoltage due to the interaction of the metal oxides, reducing electrolytic power consumption and saving energy. There is an effect that can be done.

and,? The mechanical bonding strength between the I12 electrode reactant components is strong, the chemical corrosion resistance is good, and the excellent effects are that they are always uniform.

Furthermore, although the material to be supported is platinum metal, since the supported component is a metal oxide, the overvoltage generated at the platinum metal electrode (overvoltage) is The effect is that it is possible to completely suppress even the slightest consumption of the reactant components, and in some cases, it is possible to significantly delay the time it takes to reach the overvoltage rise value J, with platinum metal electrodes. There is.

Furthermore, is the electrode reaction couple component exhausted? It is a component to be supported when the life of the fi pole is reached (increasing the amount of bu has the effect of increasing the life of the north pole, and also has the advantage of saving resources since there is no need to increase the total number of dichroic reactant components). be.

In addition, if the electrode reactant remains and reaches the end of its life at a high overvoltage, it has the effect of increasing only one portion of the electrode reactant to extend its life. There is also the benefit of not having to plan.

Applicant: Ishifuku Metal Kogyo Co., Ltd.

Claims (1)

[Claims] Integrally bonded to the electrode reactor or corrosion-resistant conductive substrate surface! ,: An electrode for electrolysis consisting of a supported material of β-porous material and a supported material three-dimensionally supported on the supported material, wherein the supported material component is porous platinum metal, and the other is a porous platinum metal. -1 component is iridium-containing Gj and 40 to 99i Kyoshi% of iridium oxide l and this to 1 and manganese and cobal 1 and its content is 1 to 60% of manganese oxide and!
1.) An electrode for electrolysis comprising at least 51 kinds of components of Pal 1.