Self-sacrificial gas-evolving anode and its preparation method

Abstract

A self-sacrificial gas evolution anode and a preparation method thereof. The conductive substrate is made of a metal material, and a metal oxide anode active coating is coated on the outer surface of the conductive substrate; the metal oxide anode active coating is jointly composed of oxides of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin and the oxide of cerium in the lanthanide elements, and the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 16-30 g / m 2 . The purpose is to provide a self-sacrificial gas evolution anode and a preparation method thereof, which can increase the active sites on the electrode surface, accelerate the gas evolution and escape speed, reduce the gas evolution potential, and at the same time can change the consumption speed of other elements in the active coating, and improve the service life of other precious metals in the coating by the self-sacrifice of cerium in the coating.

Description

Technical Field

[0001] The invention relates to the field of electrolysis, in particular to a self-sacrificial gas precipitation anode and a preparation method thereof. Background Art

[0002] In the fields of electricity and chemistry, the positive electrode refers to the electrode with high potential, and the negative electrode refers to the electrode with low potential. However, for the anode and the cathode, the anode always undergoes oxidation reaction, and the cathode always undergoes reduction reaction.

[0003] Traditional sacrificial anodes refer to the case where the theoretical metal of the electrolytic cell is used as the anode, and the anode (metal) is gradually consumed as the current flows out. Sacrificial anodes are usually only economically used in structures with small protection current requirements and in low soil resistivity environments.

[0004] In recent years, with the continuous expansion of the application of electrolysis technology in water treatment, biocatalysis and other fields, the technical requirements of improving the electrocatalytic performance of the anode while reducing the electrochemical corrosion of the anode have become the focus. In the electrolysis technology in the field of water treatment and biocatalysis, the anode needs to have good catalytic performance because the chemical reaction on the electrode surface after power is turned on, so that the reaction can continue for a long time and ensure a certain electrolysis efficiency. This can be achieved by applying an appropriate active coating to the electrode. However, another huge problem faced by the electrode after the catalytic reaction in the field of water treatment and biocatalysis is the poisoning of the active coating, such as manganese poisoning and microbial attachment in seawater electrolysis, attachment of precious metals, organic matter, microorganisms, etc. in sewage treatment, and attachment of organic matter and microorganisms in the biocatalytic process. All of these will make the active coating poisoned and ineffective. The traditional solution is to stop the electrolysis to clean or replace the electrode. On the one hand, it affects the operation of the electrolysis equipment. On the other hand, cleaning and replacement often cannot solve the fundamental problem and are costly. Summary of the invention

[0005] The purpose of the present invention is to provide a self-sacrificial gas precipitation anode and a preparation method thereof, which can increase the active points on the electrode surface, accelerate the gas precipitation and escape rate, reduce the gas precipitation potential, and at the same time change the consumption rate of other elements in the active coating, thereby increasing the service life of other precious metals in the coating through the sacrifice of cerium in the coating itself.

[0006] The self-sacrificial gas precipitation anode of the present invention comprises a conductive substrate, which is made of a metal material and is coated with a metal oxide anode active coating on the outer surface of the conductive substrate;

[0007] The metal oxide anode active coating is composed of oxides of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin and oxides of cerium in the lanthanide series. The coating amount of the metal oxide anode active coating on the surface of the conductive substrate is 16-30 g / m2 ;

[0008] In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 74%-98%, and the molar percentage of cerium is 2%-26%.

[0009] Preferably, in the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 76%-96%, and the molar percentage of cerium is 4%-24%;

[0010] The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 18-28 g / m 2 .

[0011] Preferably, the conductive substrate is made of titanium mesh. In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 80%-92%, and the molar percentage of cerium is 8%-20%;

[0012] The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 20-26 g / m 2 .

[0013] Preferably, the metal oxide anode active coating is composed of oxides of ruthenium and titanium, or ruthenium and platinum, or iridium and tantalum, or iridium and vanadium, or iridium and platinum, or iridium and tin, or ruthenium and iridium and titanium, or ruthenium and iridium and tin, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and palladium, or ruthenium and iridium and titanium and platinum, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and iron, or ruthenium and iridium and titanium and cobalt and oxides of cerium;

[0014] In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 82%-88%, and the molar percentage of cerium is 12%-16%;

[0015] The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 24-25 g / m 2 .

[0016] The preparation method of the self-sacrificing gas evolution anode of the present invention includes the following steps:

[0017] A. Prepare a conductive substrate using a metal, clean the conductive substrate to remove surface contaminants, and roughen the surface of the conductive substrate;

[0018] B. Prepare soluble salts of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin, and soluble salts of cerium. Dissolve the soluble salts of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in dilute hydrochloric acid, and add soluble salts of cerium to obtain a metal oxide anode active coating solution. Calculated by metal composition, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 160 g - 200 g / L, and the content of cerium is 1 g - 34 g / L;

[0019] C. Apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate treated in step A, heat the conductive substrate to 400°C - 550°C in an air atmosphere, and the heating time is 10 minutes - 50 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate again, heat the conductive substrate to 400°C - 550°C in an air atmosphere, and the heating time is 10 minutes - 50 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 16 - 30 g / m 2 , to obtain a self - sacrificial gas evolution anode.

[0020] Preferably, in step B, calculated by metal composition, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 165 g - 195 g / L, and the content of cerium is 3 g - 30 g / L;

[0021] In step C, heat the conductive substrate to 430°C - 520°C in an air atmosphere, and the heating time is 15 minutes - 45 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate again, heat the conductive substrate to 430°C - 520°C in an air atmosphere, and the heating time is 15 minutes - 45 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 18 - 28 g / m 2 .

[0022] Preferably, the conductive substrate is made of titanium mesh. In step B, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 170 g - 190 g / L, and the content of cerium is 8 g - 25 g / L;

[0023] In step C, the conductive substrate is heated to 450°C - 500°C in an air atmosphere, and the heating time is 20 minutes - 40 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then the metal oxide anode active coating solution obtained in step B is applied on the conductive substrate again, and the conductive substrate is heated to 450°C - 500°C in an air atmosphere, and the heating time is 20 minutes - 40 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 20 - 26 g / m 2 .

[0024] Preferably, in step B, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 175 g - 185 g / L, and the content of cerium is 12 g - 20 g / L;

[0025] In step C, the conductive substrate is heated to 460°C - 490°C in an air atmosphere, and the heating time is 25 minutes - 35 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then the metal oxide anode active coating solution obtained in step B is applied on the conductive substrate again, and the conductive substrate is heated to 460°C - 490°C in an air atmosphere, and the heating time is 25 minutes - 35 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 24 - 25 g / m 2 .

[0026] Preferably, the metal oxide anode active coating is composed of oxides of ruthenium and titanium, or ruthenium and platinum, or iridium and tantalum, or iridium and vanadium, or iridium and platinum, or iridium and tin, or ruthenium and iridium and titanium, or ruthenium and iridium and tin, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and palladium, or ruthenium and iridium and titanium and platinum, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and iron, or ruthenium and iridium and titanium and cobalt together with oxides of cerium.

[0027] The self-sacrificing gas-evolving anode of the present invention has a conductive matrix made of a metal material, and a metal oxide anode active coating is coated on the outer surface of the conductive matrix; the metal oxide anode active coating is composed of oxides of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin and an oxide of cerium in the lanthanide elements. The surface of the metal oxide anode active coating has two structures: protrusions and honeycombs. This structure, on the one hand, makes the corrosion of the self-sacrificing electrode of the present invention more uniform and finer when used as a sacrificial electrode, extending the life of the sacrificial electrode. On the other hand, when the self-sacrificing gas-evolving anode of the present invention is used as a traditional gas-evolving electrode, its honeycomb structure gives the electrode a larger surface area and capacitance, enhancing the electrode activity. The small protrusions evenly distributed on the surface of the metal oxide anode active coating also enable the gas to escape more quickly after evolution, reducing the gas evolution potential, increasing the active sites on the electrode surface, and accelerating the gas evolution and escape speed. At the same time, when used for gas evolution, cerium elements can accelerate the consumption of elements such as ruthenium, iron, cobalt, and tin, and slow down the consumption of iridium, palladium, platinum, tantalum, titanium, and vanadium. Therefore, the self-sacrificing gas-evolving anode and its preparation method of the present invention have the characteristics of increasing the active sites on the electrode surface, accelerating the gas evolution and escape speed, reducing the gas evolution potential, and at the same time changing the consumption rate of other elements in the active coating, and improving the service life of other precious metals in the coating through the self-sacrifice of cerium in the coating.

[0028] Other details and features of the self-sacrificing gas-evolving anode and its preparation method of the present invention can be clearly understood by reading the embodiments described in detail below. Detailed implementation mode

[0029] The self-sacrificing gas-evolving anode of the present invention includes a conductive matrix made of a metal material, and a metal oxide anode active coating is coated on the outer surface of the conductive matrix;

[0030] The metal oxide anode active coating is jointly composed of oxides of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin and an oxide of cerium in the lanthanide elements. The coating amount of the metal oxide anode active coating oxide on the surface of the conductive matrix is 16 - 30 g / m 2 ;

[0031] In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 74% - 98%, and the molar percentage of cerium is 2% - 26%.

[0032] As a further improvement of the present invention, in the above-mentioned metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 76%-96%, and the molar percentage of cerium is 4%-24%;

[0033] The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 18-28 g / m 2 .

[0034] As a further improvement of the present invention, the above-mentioned conductive substrate is made of titanium mesh. In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 80%-92%, and the molar percentage of cerium is 8%-20%;

[0035] The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 20-26 g / m 2 .

[0036] As a further improvement of the present invention, the above-mentioned metal oxide anode active coating is composed of oxides of ruthenium and titanium, or ruthenium and platinum, or iridium and tantalum, or iridium and vanadium, or iridium and platinum, or iridium and tin, or ruthenium and iridium and titanium, or ruthenium and iridium and tin, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and palladium, or ruthenium and iridium and titanium and platinum, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and iron, or ruthenium and iridium and titanium and cobalt together with oxides of cerium;

[0037] In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 82%-88%, and the molar percentage of cerium is 12%-16%;

[0038] The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 24-25 g / m 2 ; The surface of the metal oxide anode active coating has two structures of protrusions and honeycombs, and they are evenly distributed.

[0039] The self-sacrificial gas evolution anode of the present invention has a bright appearance. Since the surface of the metal oxide anode active coating has two structures of protrusions and honeycombs and they are evenly distributed, the active points on the electrode surface can be increased, and the gas evolution and escape speeds can be accelerated.

[0040] For the self-sacrificial gas evolution anode of the present invention, when used for gas evolution, cerium elements can accelerate the consumption of elements such as ruthenium, iron, cobalt, and tin, and slow down the consumption of iridium, palladium, platinum, tantalum, titanium, and vanadium.

[0041] The preparation method of the self-sacrificial gas evolution anode of the present invention comprises the following steps:

[0042] A. Prepare a conductive substrate using a metal, clean the conductive substrate to remove surface contaminants, and roughen the surface of the conductive substrate;

[0043] B. Prepare soluble salts of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin, and soluble salts of cerium. Dissolve the soluble salts of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in dilute hydrochloric acid, and add soluble salts of cerium to obtain a metal oxide anode active coating solution. Calculated by metal composition, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 160 g - 200 g / L, and the content of cerium is 1 g - 34 g / L;

[0044] C. Apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate treated in step A, heat the conductive substrate to 400°C - 550°C in an air atmosphere, and the heating time is 10 minutes - 50 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate again, heat the conductive substrate to 400°C - 550°C in an air atmosphere, and the heating time is 10 minutes - 50 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 16 - 30 g / m 2 , to obtain a self-sacrificial gas evolution anode.

[0045] As a further improvement of the present invention, in the above step B, calculated by metal composition, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 165 g - 195 g / L, and the content of cerium is 3 g - 30 g / L;

[0046] In the above step C, heat the conductive substrate to 430°C - 520°C in an air atmosphere, and the heating time is 15 minutes - 45 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate again, heat the conductive substrate to 430°C - 520°C in an air atmosphere, and the heating time is 15 minutes - 45 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 18 - 28 g / m 2 .

[0047] As a further improvement of the present invention, the above-mentioned conductive substrate is made of titanium mesh. In step B, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating liquid is 170 g - 190 g / L, and the content of cerium is 8 g - 25 g / L;

[0048] In step C, the conductive substrate is heated to 450°C - 500°C in an air atmosphere, and the heating time is 20 minutes - 40 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then the metal oxide anode active coating liquid obtained in step B is coated on the conductive substrate again, and the conductive substrate is heated to 450°C - 500°C in an air atmosphere, and the heating time is 20 minutes - 40 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 20 - 26 g / m 2 。

[0049] As a further improvement of the present invention, in step B above, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating liquid is 175 g - 185 g / L, and the content of cerium is 12 g - 20 g / L;

[0050] In step C, the conductive substrate is heated to 460°C - 490°C in an air atmosphere, and the heating time is 25 minutes - 35 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then the metal oxide anode active coating liquid obtained in step B is coated on the conductive substrate again, and the conductive substrate is heated to 460°C - 490°C in an air atmosphere, and the heating time is 25 minutes - 35 minutes; repeat this process multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 24 - 25 g / m 2 。

[0051] As a further improvement of the present invention, the above-mentioned metal oxide anode active coating is composed of oxides of ruthenium and titanium, or ruthenium and platinum, or iridium and tantalum, or iridium and vanadium, or iridium and platinum, or iridium and tin, or ruthenium and iridium and titanium, or ruthenium and iridium and tin, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and palladium, or ruthenium and iridium and titanium and platinum, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and iron, or ruthenium and iridium and titanium and cobalt and oxides of cerium.

[0052] Example 1

[0053] The self-sacrificial gas evolution anode of the present invention and its preparation method are as follows:

[0054] 1. Prepare the first metal oxide anode active coating solution containing ruthenium, platinum, and cerium. The total metal content of ruthenium, platinum, and cerium in the metal oxide anode active coating solution is 180 g / L, and the cerium content is 3 g / L. Prepare the second metal oxide anode active coating solution containing ruthenium, iridium, titanium, iron, and cerium. The total metal content of ruthenium, iridium, titanium, iron, and cerium in the metal oxide anode active coating solution is 180 g / L, and the cerium content is 24 g / L.

[0055] 2. The conductive substrate is made of titanium mesh, and the surface of the metal substrate of the titanium mesh is roughened and cleaned.

[0056] 3. Make the bottom layer of the active coating. Apply the first metal oxide anode active coating solution on the titanium mesh obtained in step 1, and then perform thermal oxidation treatment. The thermal oxidation temperature of the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes; then apply the first metal oxide anode active coating solution on the titanium mesh obtained in step 1 again, and then perform thermal oxidation treatment. The thermal oxidation temperature of the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes; repeat this process 6 times in total.

[0057] 4. Apply the second metal oxide anode active coating solution on the titanium mesh obtained in step 4, and then perform thermal oxidation treatment. The thermal oxidation temperature of the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes; then apply the second metal oxide anode active coating solution on the titanium mesh again, and then perform thermal oxidation treatment. The thermal oxidation temperature of the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes.

[0058] 5. Perform thermal oxidation treatment on the titanium mesh coated with the composite coating obtained in step 4. The thermal oxidation temperature of the thermal oxidation treatment is 550 °C, and the thermal oxidation time is 180 minutes to obtain the self-sacrificing gas evolution anode C1.

[0059] Example 2

[0060] The self-sacrificing gas evolution anode of the present invention and its preparation method are as follows:

[0061] 1. Prepare the iridium-tin-cerium hydrochloric acid coating solution containing iridium, tin, and cerium. The total metal content of iridium, tin, and cerium in the iridium-tin-cerium hydrochloric acid coating solution is 170 g / L, and the cerium content is 24 g / L. Prepare the ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, palladium, and cerium. The total metal content of ruthenium, iridium, titanium, palladium, and cerium in the coating solution is 170 g / L, and the cerium content is 3 g / L.

[0062] 2. Roughen and clean the surface of the titanium mesh metal substrate.

[0063] 3. Prepare the underlying layer of the active coating. Coat the iridium-tin-cerium hydrochloric acid coating solution on the titanium mesh, and then perform thermal oxidation treatment. The thermal oxidation temperature for the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes. The coating and thermal oxidation treatment are carried out 6 times. Coat the ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution on the titanium mesh with the underlying layer coated, and then perform thermal oxidation treatment. The thermal oxidation temperature for the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes. The coating and thermal oxidation treatment are carried out 2 times.

[0064] 4. Perform thermal oxidation treatment on the titanium mesh with the composite coating coated in 3. The thermal oxidation temperature for the thermal oxidation treatment is 550 °C, and the thermal oxidation time is 240 minutes to obtain the self-sacrificial gas evolution anode C2.

[0065] Example 3

[0066] The self-sacrificial gas evolution anode of the present invention and its preparation method are as follows:

[0067] 1. Prepare a ruthenium-iridium-tin-cerium hydrochloric acid coating solution containing ruthenium, iridium, tin, and cerium. The total content of ruthenium, iridium, tin, and cerium metals in the coating solution is 175 g / L, and the cerium content is 3 g / L. Prepare a ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, palladium, and cerium. The total content of ruthenium, iridium, titanium, palladium, and cerium metals in the coating solution is 175 g / L, and the cerium content is 18 g / L.

[0068] 2. Roughen and clean the surface of the titanium mesh metal substrate.

[0069] 3. Prepare the underlying layer of the active coating. Coat the ruthenium-iridium-tin-cerium hydrochloric acid coating solution on the titanium mesh, and then perform thermal oxidation treatment. The thermal oxidation temperature for the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes. The coating and thermal oxidation treatment are carried out 6 times. Coat the ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution on the titanium mesh with the underlying layer coated, and then perform thermal oxidation treatment. The thermal oxidation temperature for the thermal oxidation treatment is 515 °C, and the thermal oxidation time is 25 minutes. The coating and thermal oxidation treatment are carried out 2 times.

[0070] 4. Perform thermal oxidation treatment on the titanium mesh with the composite coating coated in 3. The thermal oxidation temperature for the thermal oxidation treatment is 550 °C, and the thermal oxidation time is 150 minutes to obtain the self-sacrificial gas evolution anode C3.

[0071] Example 4

[0072] The self-sacrificial gas evolution anode of the present invention and its preparation method are as follows:

[0073] 1. Prepare a ruthenium-platinum-cerium hydrochloric acid coating solution containing ruthenium, platinum, and cerium. The total content of ruthenium, platinum, and cerium metals in the coating solution is 175 g / L, and the cerium content is 8 g / L. Prepare a ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, palladium, and cerium. The total content of ruthenium, iridium, titanium, palladium, and cerium metals in the coating solution is 175 g / L, and the cerium content is 18 g / L.

[0074] 2. Roughen and clean the surface of the titanium mesh metal substrate.

[0075] 3. Prepare the bottom layer of the active coating. Coat the ruthenium-platinum-cerium hydrochloric acid coating solution on the titanium mesh, and then perform thermal oxidation treatment. The thermal oxidation temperature is 515 °C, the thermal oxidation time is 25 minutes, and the number of coating and thermal oxidation treatments is 6 times; coat the ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution on the titanium mesh with the bottom layer coating, and then perform thermal oxidation treatment. The thermal oxidation temperature is 515 °C, the thermal oxidation time is 25 minutes, and the number of coating and thermal oxidation treatments is 2 times.

[0076] 4. Perform thermal oxidation treatment on the titanium mesh coated with the composite coating in step 3. The thermal oxidation temperature is 550 °C, the thermal oxidation time is 150 minutes, and the self-sacrificing gas-evolving anode C4 is obtained.

[0077] Example 5

[0078] The self-sacrificing gas-evolving anode of the present invention and its preparation method are as follows:

[0079] 1. Prepare a ruthenium-iridium-titanium-iron-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, iron, and cerium. The total content of ruthenium, iridium, titanium, iron, and cerium metals in the coating solution is 175 g / L, and the cerium content is 8 g / L. Prepare a ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, palladium, and cerium. The total content of ruthenium, iridium, titanium, palladium, and cerium metals in the coating solution is 175 g / L, and the cerium content is 18 g / L.

[0080] 2. Roughen and clean the surface of the titanium mesh metal substrate.

[0081] 3. Prepare the bottom layer of the active coating. Coat the ruthenium-iridium-titanium-iron-cerium hydrochloric acid coating solution on the titanium mesh, and then perform thermal oxidation treatment. The thermal oxidation temperature is 515 °C, the thermal oxidation time is 25 minutes, and the number of coating and thermal oxidation treatments is 6 times; coat the ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution on the titanium mesh with the bottom layer coating, and then perform thermal oxidation treatment. The thermal oxidation temperature is 515 °C, the thermal oxidation time is 25 minutes, and the number of coating and thermal oxidation treatments is 2 times.

[0082] 4. Perform thermal oxidation treatment on the titanium mesh coated with the composite coating in step 3. The thermal oxidation temperature is 550 °C, the thermal oxidation time is 150 minutes, and the self-sacrificing gas-evolving anode C5 is obtained.

[0083] Example 6

[0084] The self-sacrificing gas-evolving anode of the present invention and its preparation method are as follows:

[0085] 1. Prepare a ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, palladium, and cerium. The total content of ruthenium, iridium, titanium, palladium, and cerium metals in the coating solution is 175 g / L, and the cerium content is 8 g / L. Prepare a ruthenium-iridium-titanium-iron-cerium hydrochloric acid coating solution containing ruthenium, iridium, titanium, iron, and cerium. The total content of ruthenium, iridium, titanium, iron, and cerium metals in the coating solution is 175 g / L, and the cerium content is 18 g / L.

[0086] 2. Roughen and clean the surface of the titanium mesh metal substrate.

[0087] 3. Fabricate the bottom layer of the active coating. Apply the ruthenium-iridium-titanium-palladium-cerium hydrochloric acid coating solution onto the titanium mesh, and then perform thermal oxidation treatment. The thermal oxidation temperature is 515 °C, and the thermal oxidation time is 25 minutes. The coating and thermal oxidation treatment are carried out 6 times. Apply the ruthenium-iridium-titanium-iron-cerium hydrochloric acid coating solution onto the titanium mesh with the bottom layer coating, and then perform thermal oxidation treatment. The thermal oxidation temperature is 515 °C, and the thermal oxidation time is 25 minutes. The coating and thermal oxidation treatment are carried out 2 times.

[0088] 4. Perform thermal oxidation treatment on the titanium mesh with the composite coating in step 3. The thermal oxidation temperature is 550 °C, and the thermal oxidation time is 150 minutes to obtain the self-sacrificial gas evolution anode C6.

[0089] Detect the above self-sacrificial gas evolution anodes C1 - C6 of the present invention. The detection method is as follows:

[0090] In a 32% NaOH sodium hydroxide aqueous solution at 90 °C under a current density of 8 kA / m 2 Continuously electrolyze for 4 h. Weigh with a balance to calculate the weight loss of the anode life before and after electrolysis, and use an X-ray fluorescence spectrometer to test and calculate the residual percentage of the anode coating before and after electrolysis. And detect the chlorine evolution potential and capacitance of the electrode in a 3.5 mol / L NaCl sodium chloride aqueous solution at 90 °C using an electrochemical workstation. The detection results are shown in the following table:

[0091] Table 1

[0092]

[0093] As can be seen from the data listed in the above table, for the self-sacrificial gas evolution anodes prepared by the preparation method of the present invention, the addition of cerium element in the active coating changes the porous structure form of the gas evolution electrode, reduces the gas evolution potential, and at the same time changes the consumption rate of other elements in the active coating. Through the self-sacrifice of cerium in the coating, the service life of other precious metals in the coating is significantly improved.

[0094] The present invention has conducted exploratory research on the prior art and unexpectedly found that by introducing an appropriate amount of more easily corroded elements into the anode coating, the potential of the sacrificial electrode to undergo an oxidation reaction can be changed, thereby improving the sensitivity of the sacrificial electrode and its protective ability for the working electrode. At the same time, by controlling the addition amount and proportion of the easily corroded elements, the original structure of the anode coating is changed, and the surface of the metal oxide anode active coating has two structures, protrusions and honeycombs, which are evenly distributed. On the one hand, when the self-sacrificial electrode of the present invention is used as a sacrificial electrode, the corrosion is more uniform and finer, extending the service life of the sacrificial electrode. On the other hand, when the self-sacrificial gas evolution anode of the present invention is used as a traditional gas evolution electrode, the honeycomb structure endows the electrode with a larger surface area and capacitance, enhancing the electrode activity. The small protrusions evenly distributed on the crystal surface also enable the gas to escape more quickly after evolution, reducing the gas evolution potential.

[0095] The above-described embodiments are merely descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. Self-sacrificial gas-evolving anode, characterized in that It includes a conductive substrate made of a metal material, and a metal oxide anode active coating is coated on the outer surface of the conductive substrate; The metal oxide anode active coating is composed of oxides of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin and the oxide of cerium in the lanthanide elements, and the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 16-30 g / m 2 ; In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 74%-98%, and the molar percentage of cerium is 2%-26%; The surface of the metal oxide anode active coating has two structures: protrusions and honeycombs. The two structures of protrusions and honeycombs make the corrosion of the self-sacrificing electrode more uniform and finer when used as a sacrificial electrode, extending the life of the sacrificial electrode. When the self-sacrificing gas evolution anode is used as a gas evolution electrode, the honeycomb structure gives the electrode a larger surface area and capacitance, enhancing the electrode activity. The small protrusions evenly distributed on the surface of the metal oxide anode active coating enable the gas to escape faster after evolution, reducing the gas evolution potential, increasing the active sites on the electrode surface, and accelerating the gas evolution and escape speed. At the same time, when used for gas evolution, cerium can accelerate the consumption of ruthenium, iron, cobalt, and tin elements and slow down the consumption of iridium, palladium, platinum, tantalum, titanium, and vanadium.

2. The self-sacrificial gas-evolving anode according to claim 1, characterized in that In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 76%-96%, and the molar percentage of cerium is 4%-24%; The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 18-28 g / m 2 .

3. The self-sacrificial gas-evolving anode according to claim 2, characterized in that The conductive substrate is made of a titanium mesh. In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 80%-92%, and the molar percentage of cerium is 8%-20%; The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 20-26 g / m 2 .

4. The self-sacrificial gas-evolving anode according to claim 1 or 2 or 3, characterized in that In the metal oxide anode active coating, calculated by metal components, the molar percentage of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin is 82%-88%, and the molar percentage of cerium is 12%-16%; The coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 24-25 g / m 2 .

5. The self-sacrificial gas-evolving anode according to claim 4, characterized in that The metal oxide anode active coating is composed of oxides of ruthenium and titanium, or ruthenium and platinum, or iridium and tantalum, or iridium and vanadium, or iridium and platinum, or iridium and tin, or ruthenium and iridium and titanium, or ruthenium and iridium and tin, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and palladium, or ruthenium and iridium and titanium and platinum, or ruthenium and iridium and titanium and iron, or ruthenium and iridium and titanium and cobalt and oxides of cerium.

6. Preparation method of the self-sacrificial gas-evolving anode, characterized in that It includes the following steps: A. Prepare a conductive substrate using a metal, clean the conductive substrate to remove surface contaminants, and roughen the surface of the conductive substrate; B. Prepare soluble salts of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin, as well as soluble salts of cerium. Dissolve the soluble salts of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in dilute hydrochloric acid, and add the soluble salts of cerium to obtain a metal oxide anode active coating solution. Calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 160 g - 200 g / L, and the content of cerium is 1 g - 34 g / L; C. Apply the metal oxide anode active coating solution obtained in step B onto the conductive substrate treated in step A, and heat the conductive substrate to 400°C - 550°C in an air atmosphere for 10 minutes - 50 minutes to form a metal oxide anode active coating on the surface of the conductive substrate; Then, the metal oxide anode active coating liquid obtained in step B is coated on the conductive substrate again, and the conductive substrate is heated to 400°C - 550°C in an air atmosphere for 10 minutes - 50 minutes; this is repeated multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 16 - 30 g / m 2 , and a self-sacrificing gas evolution anode is obtained; The surface of the metal oxide anode active coating has two structures: protrusions and honeycombs. The two structures of protrusions and honeycombs make the corrosion of the self-sacrificial electrode more uniform and finer when used as a sacrificial electrode, prolonging the life of the sacrificial electrode. When the self-sacrificial gas evolution anode is used as a gas evolution electrode, the honeycomb structure enables the electrode to have a larger surface area and capacitance, enhancing the electrode activity. The small protrusions evenly distributed on the surface of the metal oxide anode active coating enable the gas to escape more quickly after evolution, reducing the gas evolution potential, increasing the number of active sites on the electrode surface, and accelerating the gas evolution and escape speed. At the same time, when used for gas evolution, cerium elements can accelerate the consumption of ruthenium, iron, cobalt, and tin elements and slow down the consumption of iridium, palladium, platinum, tantalum, titanium, and vanadium.

7. The preparation method of the self-sacrificial gas-evolving anode according to claim 6, characterized in that In step B, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 165 g - 195 g / L, and the content of cerium is 3 g - 30 g / L; In step C, the conductive substrate is heated to 430°C - 520°C in an air atmosphere for 15 minutes - 45 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then the metal oxide anode active coating solution obtained in step B is applied to the conductive substrate again, and the conductive substrate is heated to 430°C - 520°C in an air atmosphere for 15 minutes - 45 minutes; this is repeated multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 18 - 28 g / m 2 .

8. The preparation method of the self-sacrificial gas-evolving anode according to claim 7, characterized in that The conductive substrate is made of a titanium mesh. In step B, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 170 g - 190 g / L, and the content of cerium is 8 g - 25 g / L; In step C, heat the conductive substrate to 450°C - 500°C in an air atmosphere for 20 minutes - 40 minutes to form a metal oxide anode active coating on the surface of the conductive substrate; Then, the metal oxide anode active coating solution obtained in step B is applied to the conductive substrate again, and the conductive substrate is heated to 450°C - 500°C in an air atmosphere for 20 minutes - 40 minutes; this is repeated multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 20 - 26 g / m 2 .

9. The preparation method of the self-sacrificial gas-evolving anode according to claim 8, characterized in that In step B, calculated by metal components, the content of ruthenium and / or iridium and / or titanium and / or palladium and / or platinum and / or cobalt and / or iron and / or tantalum and / or vanadium and / or tin in the metal oxide anode active coating solution is 175 g - 185 g / L, and the content of cerium is 12 g - 20 g / L; In the step C, the conductive substrate is heated to 460°C - 490°C in an air atmosphere, and the heating time is 25 minutes - 35 minutes, thereby forming a metal oxide anode active coating on the surface of the conductive substrate; then the metal oxide anode active coating liquid obtained in the step B is coated on the conductive substrate again, and the conductive substrate is heated to 460°C - 490°C in an air atmosphere, and the heating time is 25 minutes - 35 minutes; this is repeated multiple times until the coating amount of the metal oxide anode active coating oxide on the surface of the conductive substrate is 24 - 25 g / m 2 .

10. The preparation method of the self-sacrificial gas-evolving anode according to any one of claims 6 to 9, characterized in that The metal oxide anode active coating is composed of oxides of ruthenium and titanium, or ruthenium and platinum, or iridium and tantalum, or iridium and vanadium, or iridium and platinum, or iridium and tin, or ruthenium and iridium and titanium, or ruthenium and iridium and tin, or ruthenium and titanium and tin, or ruthenium and iridium and titanium and palladium, or ruthenium and iridium and titanium and platinum, or ruthenium and iridium and titanium and iron, or ruthenium and iridium and titanium and cobalt together with oxides of cerium.

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