KR101583179B1 - High-load durable anode for oxygen generation and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a process for the production of oxygen used for industrial electrolysis, including the production of electrolytic metal foil such as electrolytic copper foil, aluminum liquid contact, continuous galvanized steel sheet production, metal extraction, An anode and a method of manufacturing the same. The present invention relates to an oxygen generating anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate and a method of producing the same, And the coating is heat-fired in a high temperature region of 430 to 480 DEG C to form a catalyst layer containing amorphous iridium oxide, and the catalyst layer containing the amorphous iridium oxide is heated at a high temperature of 520 DEG C to 600 DEG C Baking (post-baking) in the catalytic layer to crystallize substantially all of the iridium oxide in the catalyst layer.

Description

TECHNICAL FIELD [0001] The present invention relates to an anode for generating oxygen for high load resistance and a method of manufacturing the same. BACKGROUND OF THE INVENTION [0001]

More particularly, the present invention relates to an anode for oxygen generation used in various industrial electrolysis and a method for producing the same, and more specifically, to an electrolytic metal foil such as electrolytic copper foil, an aluminum electrolytic liquid feed, An anode for oxygen generation for high load resistance having excellent durability under high load electrolysis conditions, and a method for producing the same, which are used in industrial electrolysis such as production of an electrogalvanized steel sheet and metal picking.

Industrial electrolysis such as electrolytic copper foil, aluminum hydride feed, continuous galvanized steel sheet, metal picking, etc., involves oxygen generation at the anode. For this reason, a cathode coated with iridium oxide mainly having resistance to oxygen generation as an electrode catalyst on a metallic titanium base has been widely used. Generally, in this type of industrial electrolysis involving generation of oxygen in the anode, electrolysis is often carried out at a constant current in terms of production efficiency, energy saving, and the like. The current density was set in the range of several A / dm 2, which is mainly used in the field of metal picking, to a maximum of 100 A / dm 2 for the production of electrolytic copper foil.

However, in recent years, electrolytic electrolysis is often performed at a current density of 300 A / dm 2 to 700 A / dm 2 or more in order to improve the quality of products or to give special performance characteristics. It is conceivable that such a high current is not supplied to all the anodes installed in industrial electrolytic facilities but that the anode is provided as a secondary anode at a specific point where high load electrolysis conditions are applied in order to give specific performance characteristics to products obtained from electrolysis have.

Under such high current density electrolysis, the load on the electrode catalyst layer tends to increase and current concentration tends to occur, so that consumption of the electrode catalyst layer tends to be accelerated. In addition, organic or impurity elements added to stabilize the product cause various electrochemical reactions or chemical reactions, and consequently, the hydrogen ion concentration increases as a result of the oxygen generation reaction, and the pH is lowered, thereby promoting the consumption of the electrode catalyst.

As one solution to the above problem, it may be considered to decrease the actual current load by increasing the surface area of the electrode catalyst layer. For example, physically increasing the surface area by using a substrate such as a mesh or punched metal instead of a conventional plate substrate may be a solution. However, the use of such substrates entails undesirable processing costs. In addition, the current density reduced by the surface area of the physically enhanced substrate does not improve the current concentration in the electrode catalyst layer, resulting in a slight inhibition effect on catalyst consumption.

In the thermal decomposition forming method of repeatedly coating and firing the electrode catalyst layer, if the iridium coating amount per one time increases, the formed catalyst layer may be soft and fluffy, but with this method alone, The increase of the effective surface area of the catalyst layer is weak, and the effect of suppressing the consumption of the catalyst layer and improving the durability under the high load condition is not apparent.

Electrolytic electrodes of this type are required to have electrodes with low oxygen generating potential and long lifetime. Conventionally, as this type of electrode, an insoluble electrode containing a conductive metal base such as titanium covered with a catalyst layer containing a noble metal or a noble metal oxide on a conductive metal base such as titanium is used. For example, in Patent Document 1, a catalyst layer containing iridium oxide and a valve metal oxide is coated on a conductive metal substrate such as titanium, heated in an oxidizing atmosphere, and baked at a temperature of 650 to 800 ° C to obtain a valve metal oxide An insoluble electrode manufactured by a method of partially crystallizing (crystallizing) an insoluble electrode is disclosed. However, since the electrode is fired at a temperature of 650 占 폚 or more, it causes interfacial corrosion of a metal such as titanium, becomes a poor conductor, and increases the oxygen overvoltage to an extent that it can not be used as an electrode. In addition, the crystallite diameter of iridium oxide in the catalyst layer becomes large, which leads to a decrease in the electrode effective surface area of the catalyst layer, thereby lowering the catalytic activity.

Patent Document 2 discloses the use of a positive electrode for copper plating and copper foil produced by a method of providing a catalyst layer containing a mixture of amorphous iridium oxide and amorphous tantalum oxide on a conductive metal substrate such as titanium . However, since the electrode is characterized by amorphous iridium oxide, the electrode durability was not sufficient. The reason why the amorphous iridium oxide is deteriorated when the iridium oxide is applied is because the amorphous iridium oxide shows an unstable bond between iridium and oxygen as compared with crystalline (crystalline) iridium oxide.

Patent Document 3 discloses an electrode coated with a catalyst layer including a two-layer structure of a lower layer of crystalline iridium oxide and an upper layer of amorphous iridium oxide in order to suppress consumption of the catalyst layer and improve durability of the electrode. However, in the electrode disclosed in Patent Document 3, since the upper layer of the catalyst layer is amorphous iridium oxide, the electrode durability is not sufficient. In addition, crystalline iridium oxide exists only in the lower layer and is not uniformly distributed throughout the catalyst layer, resulting in insufficient electrode durability.

Patent Document 4 discloses a zinc electrolytic sampling anode in which a catalyst layer containing amorphous iridium oxide and crystalline iridium oxide in a mixed state is provided on a conductive metal substrate such as titanium as a necessary condition. Patent Document 5 discloses a positive electrode for cobalt electrolytic picking, in which a catalyst layer containing amorphous iridium oxide and crystalline iridium oxide in a mixed state is provided on a conductive metal substrate such as titanium as a necessary condition. However, since these two electrodes contain a large amount of amorphous iridium oxide as a necessary condition, it is considered that the electrode durability is insufficient.

In order to solve the above problems, the inventors of the present invention have found that (1) low temperature firing (370 ° C. to 400 ° C.) + high temperature firing (when the iridium coating amount per unit time is 2 g / Baking (520 DEG C to 560 DEG C) after high temperature baking (410 DEG C to 450 DEG C) + high temperature baking (520 DEG C to 600 DEG C), and (2) firing method in which a catalyst layer in which crystalline iridium oxide and amorphous iridium oxide are mixed by baking ) Was developed, and two patent applications were filed in the same manner as in the present application.

According to the above-mentioned two patent applications, when the iridium coating amount ≤ 2 g / m 2 per one electrolytic condition at a current density of 100 A / dm 2 or less, lead adhesion resistance can be achieved and the increase of the effective area of the catalyst layer It is possible to improve the durability and reduce the oxygen generation overvoltage.

However, in recent years, electrolysis is often performed at a current density of 300 A / dm 2 to 700 A / dm 2 or more to improve product quality or to impart special performance characteristics. These high currents are not supplied to all the anodes installed in industrial electrolytic facilities but are installed as auxiliary anodes at specific locations where high load electrolytic conditions are applied in order to impart specific performance characteristics to products obtained from electrolysis.

Under such high current density electrolysis, the electrode catalyst layer becomes high load, and current concentration tends to occur there, so that the electrode catalyst layer is consumed quickly. Further, in order to stabilize the product, the added organic or impurity element causes various electrochemical reactions or chemical reactions, and the hydrogen ion concentration increases according to the oxygen generating reaction, the pH decreases, and the consumption of the electrode catalyst is further increased Promote. From these phenomena, the inventors of the present invention have found that, in the inventions related to the above-mentioned two patent applications, improvement in durability and reduction in oxygen generation overvoltage can not always be achieved by increasing the effective area of the catalyst layer.

Japanese Patent Application Laid-Open No. 2002-275697 (Patent No. 3654204) Japanese Patent Application Laid-Open No. 2004-238697 (Patent No. 3914162) Japanese Patent Application Laid-Open No. 2007-146215 Japanese Patent Laid-Open Publication No. 2009-293117 (Patent No. 4516617) Japanese Patent Application Laid-Open No. 2010-1556 (Patent No. 4516618)

In order to solve the above problems, the present invention improves the current distribution to the electrode catalyst layer by increasing the effective surface area of the electrode catalyst layer under high load conditions, suppresses consumption of the electrode catalyst, and improves the durability of the electrode catalyst Which has excellent durability, and a method for producing the same.

In order to achieve the above object, the present invention provides a process for producing an oxygen-containing anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, And the coating is heated and fired in a relatively high temperature region of 430 to 480 DEG C to form a catalyst layer containing amorphous iridium oxide, and the amorphous iridium oxide-containing And the catalyst layer is post-baked at an additional high-temperature region of 520 to 600 ° C to crystallize nearly all of the iridium oxide in the catalyst layer.

As a second object of the present invention, there is provided an oxygen generating anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the iridium The coating amount is 2 g / m 2, and the crystallinity (crystallinity) of the iridium oxide in the catalyst layer after the post-baking is 80%.

As a third aspect of the present invention to achieve the above object, the present invention provides an oxygen generating anode comprising a conductive metal base and a catalyst layer containing iridium oxide formed on the conductive metal base, wherein the iridium Wherein the coating amount is 2 g / m < 2 >, and the crystallite diameter of the iridium oxide in the catalyst layer is 9.0 nm.

In a fourth aspect of the present invention, there is provided an oxygen generating anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, An arc ion plating base layer containing tantalum and titanium components is formed on the conductive metal substrate by an arc ion plating process (hereinafter referred to as "AIP method"). Is provided.

In a fifth aspect of the present invention, there is provided a method for producing an oxygen-generating anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, Forming a catalyst layer containing amorphous iridium oxide on the surface of the conductive metal substrate by heating and firing at a relatively high temperature range of 430 to 480 캜 at an iridium coating amount of ≥ 2 g / Is post-baked at an additional high temperature region of 520 DEG C to 600 DEG C to crystallize substantially all of the iridium oxide in the catalyst layer.

As a sixth solution for achieving the above object, the present invention provides a method of manufacturing a semiconductor device, comprising the steps of: heating and firing a relatively high temperature region of 430 ° C to 480 ° C at an iridium coating amount of 2 g / Characterized in that a catalyst layer containing iridium oxide is formed and the catalyst layer containing the amorphous iridium oxide is post-baked at an additional high temperature region of 520 ° C to 600 ° C so that the crystallinity of iridium oxide in the catalyst layer is 80% And an anode for generating oxygen.

As a seventh solution to achieve the above object, the present invention provides a method for producing an amorphous carbon film, which comprises heating and firing a relatively high temperature region of 430 to 480 캜 at an iridium coating amount ≥ 2 g / Baking the catalyst layer containing the amorphous iridium oxide at an additional high temperature region of 520 DEG C to 600 DEG C such that the crystallite diameter of iridium oxide in the catalyst layer is 9.0 nm or less. And a cathode for generating oxygen.

As a eighth solution to achieve the above object, the present invention provides a process for producing an oxygen-generating anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, And forming an AIP base layer containing tantalum and titanium components on the conductive metal substrate by an AIP method prior to formation.

In the formation of the electrode catalyst layer containing iridium oxide according to the present invention, the iridium-coated amount of the catalyst layer is 2 g / m < 2 >, and the sintering is performed at 500 DEG C or higher, which is the perfect crystal depsosition temperature of iridium oxide. Baking at a relatively high temperature region of 430 ° C to 480 ° C to form a catalyst layer containing amorphous iridium oxide and post-baking at an additional high temperature region of 520 ° C to 600 ° C to form an electrode catalyst layer The calcination is carried out by a two-step process in which the crystallite diameter of the iridium oxide in the oxide iridium is preferably suppressed to 9.0 nm or less, and crystallization is carried out almost all of the iridium oxide, preferably crystallization degree? 80%. As a result, the growth of crystallite diameter of iridium oxide can be suppressed and the effective surface area of the catalyst layer can be increased. Therefore, the growth of crystallite diameter of iridium oxide can be suppressed by the present invention. The reasons for this are as follows: firing is carried out by repeating the coating and firing first in the relatively high temperature region of 430 ° C to 480 ° C, followed by post-baking in the further high temperature region of 520 ° C to 600 ° C This is done in a two step process. The crystallite diameter does not expand beyond a certain degree under the present invention as compared with the case where calcination is performed at a high temperature from the beginning as in the conventional method. When the crystallite diameter of iridium oxide is suppressed, the effective surface area of the catalyst layer becomes larger as the crystallite diameter is smaller. Next, the oxygen generation overvoltage of the electrode can be reduced, oxygen generation is promoted, and the reaction to form PbO ₂ from the lead ion can be suppressed. In this way, PbO ₂ attachment and coating on the electrodes can be suppressed.

Further, according to the present invention, the current distribution can be evenly dispersed while increasing the effective surface area of the catalyst layer, that is, current concentration can be suppressed, and consumption of the catalyst layer by electrolysis is reduced, which can improve electrode durability.

Further, according to the present invention, by adjusting the iridium coating amount per unit time of the catalyst layer to 2 g / m 2, the imparting of the improved quality and specific performance characteristics of the product is achieved. Even when the electrolysis is carried out at a current density of 300 A / dm 2 to 700 A / dm 2 or more, or the auxiliary anode is installed in a specific place under a high load to give the product obtained from electrolysis a special performance characteristic, The load on the electrode catalyst layer can be reduced and the current concentration can be prevented, so that consumption of the electrode catalyst layer can be suppressed.

FIG. 1 is a graph showing the change in crystallinity of iridium oxide (IrO ₂ ) in the catalyst layer due to firing temperature and post-baking temperature.
2 is a sintering temperature, and then a graph showing the change of the crystallite diameter of the iridium oxide (IrO ₂₎ of the catalyst layer due to the baking temperature.
3 is a graph showing changes in electrode electrostatic capacity due to a firing temperature and a post-bake temperature.
4 is a graph showing the dependence of the oxygen overvoltage on the firing condition.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present invention, when the effective surface area of the electrode catalyst layer is increased in order to suppress the adhesion reaction of lead oxide to the surface of the electrode, the oxygen overpotential can be reduced, thereby promoting the generation of oxygen, and at the same time, . ≪ / RTI > Further, the present invention has been completed from the idea that it is necessary that iridium oxide in the catalyst layer is mainly crystalline in order to simultaneously improve electrode durability.

In the present invention, first, a catalyst layer containing amorphous IrO ₂ is formed by firing in a relatively high temperature region of 430 ° C to 480 ° C, followed by post-baking at a further high temperature region of 520 ° C to 600 ° C to remove iridium oxide A two-stage firing is performed in which almost complete crystallization occurs.

Experiments conducted by the inventors of the present invention have revealed that a catalyst layer containing amorphous iridium oxide, which can significantly increase the effective surface area, consumes amorphous iridium oxide considerably rapidly by electrolysis and has a relatively low durability. That is, it is considered that the electrode durability can not be improved unless the iridium oxide of the catalyst layer is crystallized. Therefore, in order to achieve the object of the present invention, in which the effective surface area of the electrode catalyst layer is increased and the overvoltage of the electrode is reduced, the present invention is characterized in that the calcination of the iridium oxide And it can precipitate iridium oxide crystals smaller than those of the conventional product. Therefore, the effective surface area of the electrode catalyst layer can be increased and the overvoltage can be reduced compared with the conventional product.

In the present invention, a catalyst layer containing amorphous iridium oxide is formed by heating and firing the surface of the conductive metal base at a relatively high temperature range of 430 to 480 deg. C, and then a catalyst layer of amorphous iridium oxide is added at 520 deg. C to 600 deg. Baking in a high temperature region of the catalyst layer to almost completely crystallize the iridium oxide in the catalyst layer.

According to the present invention, the provision of improved quality or specific performance of the product is achieved by adjusting the iridium coating amount per unit time of the iridium oxide catalyst layer to 2 g / m 2. Even when the electrolysis is carried out at a current density of 300 A / dm 2 to 700 A / dm 2 or more, or even when the auxiliary anode is installed at a specific location under high load electrolysis conditions to give specific performance characteristics to the product obtained from electrolysis, The current concentration is prevented, and the consumption of the electrode catalyst layer can be suppressed.

The firing temperature in the relatively high temperature region of 430 ° C to 480 ° C and the post-bake temperature in the further high temperature region of 520 ° C to 600 ° C are determined by the crystal grain size and crystallinity of the iridium oxide formed in the catalyst layer, A catalyst layer having a low oxygen overvoltage and an excellent corrosion resistance is formed in the above temperature range.

In the present invention, the crystallite diameter of the iridium oxide can be suppressed and the effective surface area of the catalyst layer can be increased by controlling the crystallite diameter of the iridium oxide in the electrode catalyst layer to be small, preferably to the crystallite diameter of 9.0 nm. Most of them could be crystallized preferably with a degree of crystallization of 80% or more.

Before the catalyst layer is formed, interfacial corrosion of the metal gas can be further prevented if an AIP base layer containing tantalum and titanium components is provided on the conductive metal base.

Instead of the AIP base layer, TiTaO _x A base layer composed of an oxide layer may be formed.

Coating the coating solution as IrCl ₃ / Ta ₂ AIP coated titanium substrate a hydrochloric acid solution of Cl ₅ as per 3g-Ir / ㎡ and a catalyst layer in such a way that the firing at a temperature (430 to 480 ℃) to the crystallization part of the IrO ₂ / RTI > The coating and firing process was repeated until a support amount of catalyst was obtained and then post-baking was performed at an additional high temperature (520 ° C to 600 ° C) for 1 hour. An electrode sample was prepared in this manner. The prepared samples were evaluated for IrO ₂ crystallinity, oxygen generation overvoltage and electrode electrostatic capacity of the catalyst layer by X - ray, and evaluated for sulfuric acid and gelatin - added sulfuric acid electrolysis and lead adhesion test.

As a result, most of the IrO _{2 in} the formed catalyst layer was crystalline and the crystallite diameter became smaller, which enabled the effective surface area of the electrode to be increased. As a result of the evaluation of the accelerated electrolytic life, the sulfate life was about 1.4 times as long as that of the conventional product, and the gelatin-added sulfuric acid electrolytic life was about 1.5 times that of the conventional product.

Hereinafter, experimental conditions and methods according to the present invention will be described.

In order to investigate the formation temperature of the amorphous iridium oxide and the range of the post-baking temperature for subsequent crystallization, samples shown in Table 1 were prepared and subjected to X-ray diffraction, cyclic voltammetry, Respectively.

A sample was prepared as follows.

The surface of the JIS I type titanium plate was dry blast treated with iron grit (G120 size), and then subjected to acid cleaning treatment in a boiling concentrated hydrochloric acid aqueous solution for 10 minutes to perform cleaning treatment of the electrode metal gas. The cleaned electrode metal gas was set as an evaporation source in an arc ion plating apparatus using a Ti-Ta alloy target, and the surface of the electrode metal substrate was coated with a tantalum and titanium alloy base layer coating. The coating conditions are shown in Table 1.

[Table 1]

Subsequently, the coated metal gas was heat-treated at 530 DEG C for 180 minutes in an air circulating electric furnace.

Then, iridium tetrachloride and tantalized tantalum were dissolved in concentrated hydrochloric acid to prepare a coating solution, which was then applied to the coated metal substrate. After drying, thermal decomposition coating was carried out in the air circulating electric furnace at the temperature shown in Table 2 for 15 minutes to form an electrode catalyst layer made of mixed oxide of iridium oxide and tantalum oxide. The amount of the coating solution was set so that the coating thickness of the coating solution was approximately 3.0 g / m 2 in terms of iridium metal, and the coating-firing operation was repeated 9 times to obtain an electrode catalyst layer of about 27.0 g / ≪ / RTI >

Subsequently, the sample coated with the catalyst layer was subjected to post-baking for 1 hour at the temperature shown in Table 2 in an air circulating electric furnace to produce an electrolytic electrode. In addition, a sample without post-baking was prepared for comparison purposes.

A list of firing temperature and post-bake temperature of each sample is shown in Table 2.

Evaluation experiment item

(1) Measurement of crystallinity and crystallite diameter

The X-ray diffraction method was used to measure the IrO ₂ Crystallinity and crystallite diameter were measured.

The degree of crystallization was estimated from the diffraction peak intensity.

(2) Electrostatic capacitance

The cyclic voltammetry method

Electrolyte: 150 g / LH ₂ SO ₄ aqueous solution

Electrolysis temperature: 60 ℃

Electrolytic area: 10 × 10㎟

Reverse polarity: Zr plate (20 mm x 70 mm)

Reference electrode: Mercury Sulfate Electrode (SSE)

(3) Oxygen overvoltage measurement

Current interrupt method

Electrolyte: 150 g / LH ₂ SO ₄ aqueous solution

Electrolysis temperature: 60 ℃

Electrolytic area: 10 × 10㎟

Reverse polarity: Zr plate (20 mm x 70 mm)

Reference electrode: Mercury Sulfate Electrode (SSE)

[Table 2]

The change in the crystallinity of IrO ₂ by the baking temperature and post-baking temperature was as follows.

The degree of crystallization was determined by setting the intensity of the crystal diffraction peak (? = 28 占 of the conventional product to 100, and the ratio of the intensity of the crystal diffraction peak (? = 28 占) of each sample to the intensity of the conventional product as the degree of crystallization. The results are shown in Table 2. Further, a graph prepared based on the data on the degree of crystallization of Table 2 is shown in Fig.

As apparent from Table 2 and FIG. 1, it can be seen that the sample of the present invention (post-baking at a high temperature region of 430 DEG C to 480 DEG C and post-baking at an additional high temperature region of 520 DEG C to 600 DEG C) The crystallinity of the iridium oxide after the post-baking of 4 and 6 to 8 was 80%. On the other hand, a clear peak of iridium oxide attributed to the electrode catalyst layer (sample 1) by firing at 430 ° C without post-baking was not recognized, and it was confirmed that the catalyst layer of this sample was formed of amorphous iridium oxide. The degree of crystallization of the electrode catalyst layer (Sample 5) by baking at 480 DEG C without post-baking was 72%, and a large amount of amorphous iridium oxide remained. Sample 9, which is a conventional product, was completely crystallized to have a crystallinity of 100%, but had a crystallite diameter of 9.1 nm, resulting in a low electrostatic capacitance of 7.6 and a small effective surface area.

That is, with respect to the change in the degree of crystallization due to the high-temperature post-baking, a clear peak of IrO ₂ attributed to the electrode catalyst layer due to the high-temperature post-baking after firing at 430 ° C. was observed, The amorphous IrO ₂ in the catalyst layer was converted to crystalline. It was also found that the peak strength was the same as that of the conventional product at any post-baking temperature, and the amorphous IrO ₂ remained unremoved. On the other hand, the product calcined at 480 DEG C exhibited an even higher degree of crystallinity after post-baking. However, it was found that after the post-baking at 520 ° C and 560 ° C, the IrO ₂ amorphous material still remains in a small amount. On the contrary, it was found that the degree of crystallization of IrO ₂ after post-baking at 600 ° C was almost equal to that of the conventional product, and the product was completely crystallized.

Then, crystallite diameter was calculated by X-ray diffraction. The results are shown in Table 2. A graph created based on the crystallite diameter in Table 2 is shown in Fig.

The crystallite diameter of the amorphous IrO ₂ formed by firing at 430 ° C without post-baking was expressed as "0". When post-baking is performed, amorphous IrO ₂ crystallized, but it was found that the crystallite diameter of the formed crystal was smaller than that of the conventional product. In addition, the dependence of the post-baking temperature and the crystallite diameter of IrO ₂ was hardly visible.

On the other hand, it was found that the crystallite diameter of the fired product at 480 DEG C by post-baking becomes smaller than that of the conventional product regardless of the post-baking temperature. That is, the IrO ₂ crystallinity of the catalyst layer formed at low-temperature firing increased by post-baking, but the IrO ₂ An increase in crystallite diameter could be suppressed.

As can be seen from the data of the crystallite diameters in Table 2 and FIG. 2, it can be seen that in the embodiment of the present invention (high temperature calcination in a relatively high temperature region of 430 DEG C to 480 DEG C, and post-high temperature calcination in a further high temperature region of 520 DEG C to 600 DEG C, Baking) of samples 2 to 4 and 6 to 8 had a crystallite diameter of? 9.0 nm of iridium oxide. On the other hand, no clear peak of iridium oxide attributed to the electrode catalyst layer (Sample 1) treated by firing at 430 ° C without post-baking was recognized, and it was confirmed that the catalyst layer of this sample was formed of amorphous iridium oxide Respectively. The crystallite diameter of the electrode catalyst layer (Sample 5) treated by firing at 480 DEG C without post-baking was as large as 9.3 nm. The crystallite diameter of the iridium oxide of Sample 9, which is a conventional product, was 9.1 nm.

Subsequently, the change in the effective surface area of the electrode catalyst layer was measured by post-baking at a high temperature of 430 ° C to 480 ° C and a high temperature of + 520 ° C to 600 ° C.

Table 2 shows the electrode capacitance calculated by the cyclic voltammetry method. The electrostatic capacitance of the electrode is proportional to the effective surface area of the electrode, and when the so-called electrostatic capacity is increased, the effective surface area can be said to be high. A relationship diagram between the firing conditions of the catalyst layer and the electrostatic capacity based on the data in Table 2 is shown in Fig.

From Table 2 and Figure 3 it can be seen that Samples 2 to 4 and 6 < RTI ID = 0.0 > (OMEGA < / RTI > And the electrostatic capacity of the electrode of the present invention was 11.6 or more. On the other hand, IrO ₂ (Sample 1) of the catalyst layer formed by firing at 430 ° C without post-baking exhibited the maximum effective surface area (electrostatic capacity) because it was amorphous. After the post-baking, the effective surface area (electrostatic capacity) was decreased because IrO ₂ crystallized, but it was found to be higher than that of the conventional products. This is thought to be because the crystallite diameter formed is smaller than that of the conventional product. In addition, there was a tendency to decrease the electrode effective surface area (electrostatic capacity) by increasing the post-baking temperature.

In addition, it was found that the effective surface area (electrostatic capacity) was almost the same in the case of post-baking after baking at 480 占 폚 (samples 5 to 8) regardless of the post-baking temperature, . This is thought to be because the IrO ₂ crystallite diameter is smaller than the conventional product, and is left with a small amount of amorphous IrO _2. Further, even when the post-baking temperature was raised, no change in electrode effective surface area (electrostatic capacity) was observed.

The oxygen overvoltage (V vs. SSE at 100 A / dm 2) of each sample was measured. The results are shown in Table 2. The dependence of the firing condition and the oxygen overvoltage is also shown in Fig. The tendency of change of the graph of Fig. 4 is opposite to that of Fig. 3, and as the electrode effective surface area increases, the oxygen overvoltage of the sample tends to decrease. It is considered that this is because the current distribution due to the increase of the electrode effective surface area can be dispersed and the actual current is lowered.

The 430 ° C calcined product with maximum effective surface area exhibited the lowest oxygen overvoltage but increased oxygen overvoltage by reducing the effective surface area by post-baking. The dependence of the oxygen overvoltage and post-baking temperature of the baked product at 480 ° C showed the same tendency. It was also found that the oxygen overvoltage of these samples was higher than that of the conventional products. This is thought to be due to an increase in surface area compared with the conventional product.

From Table 2 and Figure 4 it can be seen that Samples 2 to 4 and 6 < RTI ID = 0.0 > (I) < / RTI > To < RTI ID = 0.0 > 8 < / RTI >

As described above, the electrode fabricated by firing at a high temperature in a relatively high temperature range of 430 DEG C to 480 DEG C and a firing means in a further high temperature range of 520 DEG C to 600 DEG C by post-bake, The IrO ₂ crystal was small and the electrode surface area could be increased. These samples are able to disperse the current distribution under high load conditions and reduce the actual current load, so that the effect of suppressing the catalyst consumption is high and the improvement of the durability is also expected to be expected.

Example

Next, embodiments of the present invention will be described, but the present invention is not limited thereto.

≪ Example 1 >

The surface of the JIS I-type titanium plate was subjected to a dry blast treatment with iron grit (G120 size) and then subjected to a pickling treatment in a boiling concentrated hydrochloric acid aqueous solution for 10 minutes to perform cleaning treatment of the electrode metal gas. The cleaned electrode metal gas was set as an evaporation source in an arc ion plating apparatus using a Ti-Ta alloy target, and an AIP base layer coating coating containing tantalum and titanium was performed on the electrode metal base surface. The coating conditions are the same as in Table 1.

Then, the coated metal gas was heat-treated at 530 DEG C for 180 minutes in an air circulating electric furnace.

Next, iridium tetrachloride and tantalized tantalum were dissolved in concentrated hydrochloric acid to prepare a coating solution, which was then applied to the coated metal gas. After drying, thermal decomposition coating was carried out at 480 DEG C for 15 minutes in an air circulating electric furnace to form an electrode catalyst layer containing a mixed oxide of iridium oxide and tantalum oxide. The amount of the coating solution was set so that the coating thickness of the coating solution was almost 3.0 g / m 2 in terms of iridium metal, and the coating-firing operation was repeated nine times to obtain an electrode having an electrode of about 27.0 g / Thereby obtaining a catalyst layer.

As a result of performing X-ray diffraction on this sample, although a clear peak of iridium oxide attributed to the electrode catalyst layer was recognized, the peak intensity was lower than that of Comparative Example 1, and it was found that the crystalline IrO ₂ partially precipitated.

Subsequently, the sample coated with the catalyst layer was further subjected to post-baking at 520 DEG C for 1 hour in an air circulating electric furnace to prepare an electrolytic electrode.

As a result of performing X-ray diffraction on the sample after the post-baking, a clear peak of IrO ₂ attributed to the electrode catalyst layer appeared, and the intensity of the peak was higher than that before the post-baking but was still lower than that of Comparative Example 1 . From this, it was found that although the degree of crystallization of the catalyst layer formed by the low temperature baking process before high temperature post-baking was increased, the amorphous IrO ₂ still remained partially.

Two types of life evaluation tests (both of a pure sulfuric acid solution and a gelatin-added sulfuric acid solution) shown in Table 3 were performed on the electrolytic electrode thus produced. The results are shown in Table 4. It was clear that the durability against sulfuric acid or the organic additive was improved because the sulfuric acid electrolytic life span was 1.7 times and the gelatin electrolytic water life was 1.1 times that of Comparative Example 1 (conventional product) shown in Table 4.

[Table 3]

≪ Example 2 >

The evaluation electrode was prepared in the same manner as in Example 1 except that the temperature for post-baking in the air circulating electric furnace was changed to 560 캜, and then the same electrolytic evaluation was carried out.

As a result of X-ray diffraction after post-baking, the degree of crystallization and the crystallite diameter of IrO _{2 in} the catalyst layer were found to be about the same as in Example 1.

As shown in Table 4, as compared with Comparative Example 1 (conventional product) shown in Table 4, since the sulfuric acid electrolytic life span was 1.5 times and the gelatin electrolytic water life was 1.3 times, the durability against sulfuric acid or organic additives was both improved Respectively.

≪ Comparative Example 1 &

The firing temperature and the firing time in the air circulating electric furnace of Example 1 were changed to 520 ° C for 15 minutes to form an electrode catalyst layer made of a mixed oxide of iridium oxide and tantalum oxide. The electrode thus produced was subjected to the same X-ray diffraction and electrolysis evaluation as in Example 1, without post-baking.

As a result of performing X-ray diffraction on this sample, a clear peak of iridium oxide attributed to the electrode catalyst layer was recognized, and it was confirmed that IrO ₂ in the catalyst layer was crystalline.

The life evaluation was performed in the same manner as in Example 1. From the results shown in Table 4, it was clear that the durability against electrolysis under high load conditions was improved by the formation of the catalyst layer of low temperature firing + high temperature post-baking proposed in the present invention.

≪ Comparative Example 2 &

The evaluation electrode was prepared in the same manner as in Example 1 except that the post-baking was not performed, and then the same electrolytic evaluation as in Example 1 was carried out.

As shown in Table 4, the sulfate life and gelatin electrolytic life of the electrode baked at 480 占 폚 without post-baking were equivalent to those of the conventional product of Comparative Example 1, and the durability improvement effect did not appear.

[Table 4]

Industrial availability

TECHNICAL FIELD The present invention relates to an anode for generating oxygen for use in various industrial electrolysis and a method of producing the same, and more specifically, to a method for producing an electrolytic metal foil such as an electrolytic copper foil, feeding in an aluminum liquid, producing a continuous galvanized steel sheet, And can be used as an oxygen generating anode for high-temperature and high-load-carrying high load durability under high load electrolysis conditions, which is used in industrial electrolysis.

Claims (8)

1. An anode for generating oxygen, comprising a conductive metal substrate and a catalyst layer containing iridium oxide and tantalum oxide formed on the conductive metal substrate, wherein the iridium coating amount per unit time of the catalyst layer is 2 g / And the coating is heat-fired in a high-temperature region of 430 to 480 DEG C to form a catalyst layer containing tantalum oxide and amorphous iridium oxide, and the catalyst layer containing tantalum oxide and amorphous iridium oxide is heated to a temperature of 520 to 600 DEG C And post-baking in an additional high-temperature region to crystallize iridium oxide in the catalyst layer. The method according to claim 1,
And a catalyst layer containing iridium oxide and tantalum oxide formed on the conductive metal substrate, wherein the iridium coating amount per one time of the catalyst layer is 2 g / m < 2 >, and the crystallinity of the iridium oxide in the catalyst layer after the post- ≪ / RTI > 80%. The method according to claim 1,
And a catalyst layer containing iridium oxide and tantalum oxide formed on the conductive metal substrate, wherein the iridium coating amount per one time of the catalyst layer is? 2 g / m 2, the crystallite diameter of the iridium oxide in the catalyst layer is? 9.0 nm Wherein the anode is made of a metal. 4. The method according to any one of claims 1 to 3,
And a catalyst layer containing iridium oxide and tantalum oxide formed on the conductive metal substrate, wherein the tantalum and / or tantalum oxide is formed on the conductive metal substrate by an arc ion plating process before forming the catalyst layer, Wherein an arc ion plating base layer containing titanium components is formed. A production method of an oxygen-generating anode comprising a catalyst layer containing iridium oxide and tantalum oxide on the surface of a conductive metal substrate,
Applying a coating solution for forming a catalyst layer on the surface of the conductive metal substrate, wherein the coating solution contains a raw material of iridium oxide and tantalum oxide, or contains an iridium salt or a tantalum salt , And the iridium coating amount per unit time of the catalyst layer is 2 g / m 2;
Heating and firing the conductive metal gas in a high temperature region of 430 ° C to 480 ° C in an oxidizing atmosphere to coexist amorphous and crystalline iridium oxide; And
Post-baking the conductive metal gas in an oxidizing atmosphere at an additional high temperature region of 520 ° C to 600 ° C to crystallize iridium oxide in the catalyst layer
Wherein the cathode is made of a metal. 6. The method of claim 5,
Forming a catalytic layer containing tantalum oxide and amorphous iridium oxide on the surface of the conductive metal substrate by heating and firing at a high temperature region of 430 ° C to 480 ° C at an iridium coating amount of 2 g / Wherein the catalyst layer containing amorphous iridium oxide is post-baked at an additional high temperature region of 520 DEG C to 600 DEG C such that the crystallinity of the iridium oxide in the catalyst layer is 80%. 6. The method of claim 5,
Forming a catalytic layer containing tantalum oxide and amorphous iridium oxide on the surface of the conductive metal substrate by heating and firing at a high temperature region of 430 ° C to 480 ° C at an iridium coating amount of 2 g / Baking the catalyst layer containing amorphous iridium oxide at an additional high temperature region of 520 DEG C to 600 DEG C such that the crystallite diameter of the iridium oxide in the catalyst layer is 9.0 nm or less. 8. The method according to any one of claims 5 to 7,
A method for producing an oxygen-generating anode comprising a conductive metal substrate and a catalyst layer containing iridium oxide and tantalum oxide formed on the conductive metal substrate, wherein the conductive metal substrate phase Wherein an arc ion plating base layer containing tantalum and titanium components is formed on the surface of the substrate.

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