Surfactant modified titanium anode coating as well as preparation method and application thereof

Abstract

The invention discloses a surface active agent modified titanium anode coating and a preparation method and application thereof, and belongs to the technical field of electrode material coatings, the surface active agent modified titanium anode coating comprises an iridium tantalum oxide coating added with a surface active agent, and the surface active agent is polyacrylamide or polyethylene glycol; and the use amount of the surfactant is 30-70% of the critical micelle concentration. The preparation method comprises the following steps: uniformly mixing the surfactant and the active iridium tantalum oxide coating liquid; depositing the iridium tantalum oxide coating liquid containing the surfactant on the titanium substrate containing the intermediate layer according to a deposition method; and the deposition operation is repeated until the iridium content in the iridium tantalum oxide coating reaches the standard. The surface of the coating provided by the invention is in a three-dimensional porous shape with proper pore diameter, and the electrochemical activity and the service life of the titanium anode surface coating catalyst are remarkably improved and prolonged. The preparation process provided by the invention is simple, feasible, safe, green, low in cost and beneficial to industrial production.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of electrode material coatings, and specifically to a surfactant-modified titanium anode coating, its preparation method and application. Background Art

[0002] In the 1870s, the development of iridium-tantalum mixed metal oxide coatings was successful, which laid the foundation for their application in the electrochemically oxygen evolution reaction. Since then, with the development of materials science and electrochemistry theory, significant achievements have been made in the performance improvement and application expansion of titanium anode iridium-tantalum oxide coatings. For example, in the chlor-alkali industry, it is used for electrolyzing brine to produce chlorine and sodium hydroxide, and its excellent corrosion resistance and electrocatalytic activity ensure the high efficiency and stability of production. In the metallurgical industry, especially in the processes of electrolytic refining and electrodeposition, this coating can improve the purity and output of metals. For example, in the electrolytic refining of copper, it can effectively reduce energy consumption, improve current efficiency, and reduce the incorporation of impurities. In addition, in the PCB horizontal copper plating process in the electronics industry, the titanium anode iridium-tantalum oxide coating can ensure the uniformity and quality of the coating and improve production efficiency due to its good electrochemical performance. In fields such as aluminum foil formation, it can also significantly improve the performance and quality of products.

[0003] In the existing preparation methods of titanium anode plates, the thermal oxidation decomposition process is the most common preparation method for noble metal active coating titanium anodes due to its simple production process and low equipment cost. However, it requires a relatively high sintering temperature, the surface of the prepared electrode is not uniform enough, the density is poor, and it is easy to fall off, resulting in less than ideal service life and activation performance. Theoretically, an anode with a three-dimensional porous morphology can significantly improve the electroplating efficiency, improve the coating quality, and reduce energy consumption due to its large surface area, good electrical conductivity, and electrolyte permeability. However, too large voids will cause organic additives to penetrate and corrode the internal coating and substrate, so it is necessary to control the pore size of the three-dimensional porous morphology.

[0004] At present, the methods for forming a three-dimensional porous morphology mainly include chemical vapor deposition, sol-gel method, etc. Chemical vapor deposition usually has relatively high requirements for equipment, and the process of chemical vapor deposition is usually relatively slow. Especially when preparing a three-dimensional porous structure, it takes a long time to reach the required thickness and porosity, resulting in low production efficiency. In addition, during the chemical vapor deposition process, some impurities may be introduced, such as unreacted precursors, by-products, etc. These impurities will affect the purity and performance of the three-dimensional porous material and need to be removed through complex post-treatment processes. Although the sol-gel method can control the formation of the porous morphology to a certain extent, during the sol-gel process, as the solvent volatilizes, the gel will shrink, which may lead to deformation, cracking or even collapse of the three-dimensional porous structure, thus affecting the uniformity of its porosity and pore structure. Moreover, the gelation time is difficult to control. If the gelation is too fast, the precursors may not be mixed evenly, affecting the performance of the material. If the gelation is too slow, the preparation cycle will be prolonged. Summary of the Invention

[0005] The technical solution of the present invention aims at the technical problem that the existing technical solutions are too single, and provides a solution significantly different from the existing technologies. It mainly provides a surfactant-modified titanium anode coating, its preparation method and application, so as to solve the technical problems of the existing iridium-tantalum mixed metal oxide coating with unsatisfactory service life and activation performance and complex and difficult-to-control preparation method proposed in the above background technology.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: A surfactant-modified titanium anode coating, comprising an iridium-tantalum oxide coating added with a surfactant, wherein the surfactant is polyacrylamide or polyethylene glycol; the dosage of the surfactant is 30-70% of its critical micelle concentration.

[0007] Further, the modified titanium anode coating is an IrO 2 -Ta 2 O 5 -polyacrylamide coating or an IrO 2 -Ta 2 O 5 -polyethylene glycol coating.

[0008] Further, the iridium content in the modified titanium anode coating is 18-28 g / m 2 .

[0009] The present invention also discloses a preparation method of the above surfactant-modified titanium anode coating, comprising the following steps: S1. Prepare an active iridium-tantalum oxide coating solution for the titanium anode; S2. Mix the surfactant and the iridium tantalum oxide coating solution evenly to obtain an iridium tantalum oxide coating solution containing the surfactant; S3. Deposit the iridium tantalum oxide coating solution containing the surfactant on the titanium substrate with an intermediate layer by the deposition method; S4. Repeat the deposition operation in step S3 until the iridium content in the iridium tantalum oxide coating meets the standard, that is, a surfactant-modified titanium anode coating is prepared.

[0010] Further, in step S1, the molar ratio of iridium to tantalum in the active iridium tantalum oxide coating solution is 7:3.

[0011] Further, in step S2, the specific operation for mixing evenly is: first stir magnetically for 0.5 - 2 h, and then disperse ultrasonically for 0.5 - 2 h.

[0012] Further, in step S3, the mass of the iridium tantalum oxide coating solution containing the surfactant taken is 15 - 25 g / m 2 .

[0013] Further, in step S3, the deposition method is: evenly coat the iridium tantalum oxide coating solution containing the surfactant on the titanium substrate with an intermediate layer, dry at room temperature, and then perform oxidation treatment at 480 - 550 °C in a trolley furnace for 20 - 60 min.

[0014] Further, in step S3, the titanium substrate is a titanium plate that has been sandblasted for shape correction and pickled and etched.

[0015] The present invention also discloses an application of the surfactant-modified titanium anode coating. The surfactant-modified titanium anode coating prepared by the above preparation method is used as an electrolysis water anode reaction catalyst.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) In the present invention, polyacrylamide / polyethylene glycol is introduced into the iridium tantalum oxide coating to prepare a surfactant-modified titanium anode coating, and the addition amount of the surfactant is controlled (at 30 - 70% of its critical micelle concentration), thereby adjusting the network structure in the surfactant-modified titanium anode coating, and finally the prepared nanomaterial has a three-dimensional porous nanoparticle morphology with appropriate pore size. It can be seen from the surface SEM image that the surface of the iridium tantalum oxide coating has the effects of high dispersion, homogenization, high specific surface area and refined grains. It can increase the true specific surface area of the material and improve the microscopic morphology of the catalytic coating, and significantly improve the electrochemical activity and service life of the catalyst on the surface coating of the titanium anode.

[0017] (2) The three-dimensional porous morphology on the surface of the modified iridium tantalum oxide coating prepared in the present invention has an appropriate pore size, can pass through the electrolyte, and at the same time prevents the organic additive from passing through, effectively avoiding the penetration of the organic additive to corrode the internal coating and substrate.

[0018] (3) The preparation method of the present invention is a coating and sintering method. Compared with the chemical vapor deposition method, it has lower requirements for equipment, and the deposition process is faster. It can easily achieve the required thickness and porosity, with high production efficiency, and no impurities will be introduced. Compared with the sol-gel method, the porosity and the uniformity of the pore structure are better, and the reaction is easy to control. Therefore, the preparation method provided by the present invention is simple, easy to implement, safe, green, and low-cost, which is beneficial to industrial production.

[0019] The present invention will be explained and described in detail below in conjunction with the drawings and specific embodiments. Description of the Drawings

[0020] Figure 1 It is the SEM image of the surface of the samples in the first to fourth embodiments of the present invention; in the figure, 500X, 2000X, 20000X, and 50000X represent different magnification factors; Figure 2 It is the SEM image of the surface of the samples in the first to fourth comparative examples of the present invention; in the figure, 500X, 2000X, 20000X, and 50000X represent different magnification factors; Figure 3 It is the SEM image of the surface of the samples in the fifth to seventh comparative examples of the present invention; in the figure, 500X, 2000X, 20000X, and 50000X represent different magnification factors; Figure 4 It is the curve graph of the cell voltage changing with time when the samples in the first to fourth embodiments of the present invention and the first to seventh comparative examples are experimented. Specific Embodiments

[0021] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0022] Embodiment 1: Prepare a surfactant-modified titanium anode coating (IrO 2 -Ta 2 O 5 -polyacrylamide coating), and the specific steps are as follows: 1) Prepare the active iridium-tantalum oxide coating solution for the titanium anode with chloroiridic acid and tantalum chloride. The molar ratio of iridium to tantalum in this coating solution is 7:3; 2) Mix polyacrylamide and the active iridium-tantalum oxide coating solution in a ratio of 1:200. At this time, the dosage of polyacrylamide is 50% of the critical micelle concentration. After magnetic stirring for 30 min, ultrasonic dispersion is carried out for 60 min to obtain IrO 2 -Ta 2 O5 - Polyacrylamide coating solution; 3) Sandblast and shape the titanium substrate, and perform pickling etching to make the surface of the substrate free of foreign objects and have a certain roughness, and then deposit an intermediate layer on the substrate; 4) IrO 2 - Ta 2 O 5 - Polyacrylamide coating solution is uniformly coated onto the titanium substrate containing the intermediate layer at a dosage of 17 g / m 2 . After drying at room temperature, it is subjected to oxidation treatment at 500 °C for 40 min in a trolley furnace; 5) Repeat the coating and sintering operations in step 4 for the titanium anode until the iridium content in the iridium tantalum oxide coating of the titanium anode reaches 18 - 28 g / m 2 .

[0023] Example 2: Prepare a surfactant - modified titanium anode coating (IrO 2 - Ta 2 O 5 - Polyethylene glycol coating), and the specific steps are as follows: 1) Prepare an active iridium tantalum oxide coating solution for the titanium anode with chloro - iridic acid and tantalum chloride, and the molar ratio of iridium to tantalum in this coating solution is 7:3; 2) Mix polyethylene glycol and the active iridium tantalum oxide coating solution in a ratio of 1:100. At this time, the dosage of polyethylene glycol is 50% of the critical micelle concentration. After magnetic stirring for 30 min, ultrasonic dispersion is carried out for 60 min to obtain IrO 2 - Ta 2 O 5 - Polyethylene glycol coating solution; 3) Sandblast and shape the titanium substrate, and perform pickling etching to make the surface of the substrate free of foreign objects and have a certain roughness, and then deposit an intermediate layer on the substrate; 4) IrO 2 - Ta 2 O 5 - Polyethylene glycol coating solution is uniformly coated onto the titanium substrate containing the intermediate layer at a dosage of 17 g / m 2 . After drying at room temperature, it is subjected to oxidation treatment at 500 °C for 40 min in a trolley furnace; 5) Repeat the coating and sintering operations in step 4 for the titanium anode until the iridium content in the iridium tantalum oxide coating of the titanium anode reaches 18 - 28 g / m 2 .

[0024] Example 3: Prepare a surfactant - modified titanium anode coating (IrO 2 - Ta 2 O 5 - Polyacrylamide coating), and the specific steps are as follows: 1) Prepare the active iridium tantalum oxide coating solution for the titanium anode using iridium chloroacid and tantalum chloride. The molar ratio of iridium to tantalum in this coating solution is 7:3; 2) Mix polyacrylamide and the active iridium tantalum oxide coating solution in a ratio of 7:1000. At this time, the dosage of polyacrylamide is 70% of the critical micelle concentration. After magnetic stirring for 2 h, perform ultrasonic dispersion for 2 h to obtain IrO 2 -Ta 2 O 5 -polyacrylamide coating solution; 3) Carry out sandblasting for shape correction and pickling etching on the titanium substrate to make the surface of the substrate free of foreign objects and have a certain roughness, and then deposit an intermediate layer on the substrate; 4) Uniformly coat the IrO 2 -Ta 2 O 5 -polyacrylamide coating solution onto the titanium substrate containing the intermediate layer at a dosage of 25 g / m 2 . After drying at room temperature, perform oxidation treatment at 550 °C in a trolley furnace for 20 min; 5) Repeat the coating and sintering operations in step 4 for the titanium anode until the iridium content in the iridium tantalum oxide coating of the titanium anode reaches 18 - 28 g / m 2 .

[0025] Example 4: Prepare a surfactant-modified titanium anode coating (IrO 2 -Ta 2 O 5 -polyacrylamide coating), and the specific steps are as follows: 1) Prepare the active iridium tantalum oxide coating solution for the titanium anode using iridium chloroacid and tantalum chloride. The molar ratio of iridium to tantalum in this coating solution is 7:3; 2) Mix polyacrylamide and the active iridium tantalum oxide coating solution in a ratio of 3:1000. At this time, the dosage of polyacrylamide is 30% of the critical micelle concentration. After magnetic stirring for 1 h, perform ultrasonic dispersion for 30 min to obtain IrO 2 -Ta 2 O 5 -polyacrylamide coating solution; 3) Carry out sandblasting for shape correction and pickling etching on the titanium substrate to make the surface of the substrate free of foreign objects and have a certain roughness, and then deposit an intermediate layer on the substrate; 4) Uniformly coat the IrO 2 -Ta 2 O 5 -polyacrylamide coating solution onto the titanium substrate containing the intermediate layer at a dosage of 15 g / m 2 . After drying at room temperature, perform oxidation treatment at 480 °C in a trolley furnace for 60 min; 5) Repeat the coating and sintering actions in step 4 for the titanium anode until the iridium content in the iridium-tantalum oxide coating of the titanium anode reaches 18 - 28 g / m 2 .

[0026] Comparative Example 1: Method for preparing an IrO 2 -Ta 2 O 5 coating, the specific steps are as follows: 1) Prepare the active iridium-tantalum oxide coating solution for the titanium anode with chloroiridic acid and tantalum chloride, and the molar ratio of iridium to tantalum in this coating solution is 7:3; 2) Perform sandblasting for shape correction and pickling etching on the titanium substrate to make the surface of the substrate free of foreign objects and have a certain roughness, and then deposit an intermediate layer on the substrate; 3) Uniformly coat the IrO 2 -Ta 2 O 5 coating solution onto the titanium substrate containing the intermediate layer at a dosage of 17 g / m 2 , dry at room temperature, and then perform oxidation treatment in a trolley furnace at 480 - 550 °C for 20 - 60 min; 4) Repeat the coating and sintering actions in step 3 for the titanium anode until the iridium content in the iridium-tantalum oxide coating of the titanium anode reaches 18 - 28 g / m 2 .

[0027] Comparative Example 2: Method for preparing an IrO 2 -Ta 2 O 5 -sodium dodecylsulfonate coating, the difference from Example 1 is: Step 2): Mix sodium dodecylsulfonate and the active iridium-tantalum oxide coating solution in a ratio of 1:1000. At this time, the dosage of sodium dodecylsulfonate is 50% of the critical micelle concentration. After magnetic stirring for 30 min and ultrasonic dispersion for 60 min, obtain the IrO 2 -Ta 2 O 5 -sodium dodecylsulfonate coating solution; In the subsequent steps, use the IrO 2 -Ta 2 O 5 -sodium dodecylsulfonate coating solution to replace the IrO 2 -Ta 2 O 5 -polyacrylamide coating solution, and the others are the same as in Example 1.

[0028] Comparative Example 3: Method for preparing an IrO 2 -Ta 2 O 5 -hexadecyl dimethyl benzyl ammonium chloride coating, the difference from Example 1 is: Step 2): Mix cetyl dimethyl benzyl ammonium chloride and the active iridium tantalum oxide coating solution in a ratio of 1:300. At this time, the dosage of cetyl dimethyl benzyl ammonium chloride is 50% of the critical micelle concentration. After magnetic stirring for 30 min, perform ultrasonic dispersion for 60 min to obtain IrO 2 -Ta 2 O 5 -cetyl dimethyl benzyl ammonium chloride coating solution; In subsequent steps, use the IrO 2 -Ta 2 O 5 -cetyl dimethyl benzyl ammonium chloride coating solution to replace IrO 2 -Ta 2 O 5 -polyacrylamide coating solution, and the other steps are the same as in Example 1.

[0029] Comparative Example 4: Method for preparing an IrO 2 -Ta 2 O 5 -dodecyl dimethyl betaine coating, the difference from Example 1 is: Step 2): Mix dodecyl dimethyl betaine and the active iridium tantalum oxide coating solution in a ratio of 1:1000. At this time, the dosage of dodecyl dimethyl betaine is 50% of the critical micelle concentration. After magnetic stirring for 30 min, perform ultrasonic dispersion for 60 min to obtain IrO 2 -Ta 2 O 5 -dodecyl dimethyl betaine coating solution; In subsequent steps, use the IrO 2 -Ta 2 O 5 -dodecyl dimethyl betaine coating solution to replace IrO 2 -Ta 2 O 5 -polyacrylamide coating solution, and the other steps are the same as in Example 1.

[0030] Comparative Example 5: Method for preparing an IrO 2 -Ta 2 O 5 -isopropanolamine coating, the difference from Example 1 is: Step 2): Mix isopropanolamine and the active iridium tantalum oxide coating solution in a ratio of 1:400. At this time, the dosage of isopropanolamine is 50% of the critical micelle concentration. After magnetic stirring for 30 min, perform ultrasonic dispersion for 60 min to obtain IrO 2 -Ta 2 O 5 -isopropanolamine coating solution; In subsequent steps, use the IrO2 -Ta 2 O 5 - Replace the IrO 2 -Ta 2 O 5 - polyacrylamide coating solution, and the others are the same as in Example 1.

[0031] Comparative Example 6: Preparation of IrO 2 -Ta 2 O 5 - Method for preparing a polyvinyl alcohol coating, which is different from Example 1 in that: Step 2): Mix polyvinyl alcohol and the active iridium tantalum oxide coating solution in a ratio of 1:500. At this time, the amount of polyvinyl alcohol used is 50% of the critical micelle concentration. After magnetic stirring for 30 min, ultrasonic dispersion is carried out for 60 min to obtain IrO 2 -Ta 2 O 5 - polyvinyl alcohol coating solution; In the subsequent steps, use IrO 2 -Ta 2 O 5 - polyvinyl alcohol coating solution to replace IrO 2 -Ta 2 O 5 - polyacrylamide coating solution, and the others are the same as in Example 1.

[0032] Comparative Example 7: Preparation of IrO 2 -Ta 2 O 5 - Method for preparing a polyvinylpyrrolidone coating, which is different from Example 1 in that: Step 2): Mix polyvinylpyrrolidone and the active iridium tantalum oxide coating solution in a ratio of 1:400. At this time, the amount of polyvinylpyrrolidone used is 50% of the critical micelle concentration. After magnetic stirring for 30 min, ultrasonic dispersion is carried out for 60 min to obtain IrO 2 -Ta 2 O 5 - polyvinylpyrrolidone coating solution; In the subsequent steps, use IrO 2 -Ta 2 O 5 - polyvinylpyrrolidone coating solution to replace IrO 2 -Ta 2 O 5 - polyacrylamide coating solution, and the others are the same as in Example 1.

[0033] For Examples 1 to 4 and Comparative Examples 1 to 7, observe the SEM images of the surfaces of each sample, as Figures 1 - 3 shown. Among them, Figure 1In which, a-d are SEM images of the surface of the sample in Example 1, Figure 1 e-h are SEM images of the surface of the sample in Example 2, Figure 1 i-l are SEM images of the surface of the sample in Example 3, Figure 1 m-p are SEM images of the surface of the sample in Example 4; Figure 2 a-d are SEM images of the surface of the sample in Comparative Example 1, Figure 2 e-h are SEM images of the surface of the sample in Comparative Example 2, Figure 2 i-l are SEM images of the surface of the sample in Comparative Example 3, Figure 2 m-p are SEM images of the surface of the sample in Comparative Example 4; Figure 3 a-d are SEM images of the surface of the sample in Comparative Example 5, Figure 3 e-h are SEM images of the surface of the sample in Comparative Example 6, Figure 3 i-l are SEM images of the surface of the sample in Comparative Example 7.

[0034] It can be seen from Figures 1 - 3 that the surface morphologies of the samples in Example 1 and Example 2 are superior to those in Comparative Examples 1-7, and it can be seen from Figure 1 a-h that by adding polyacrylamide or polyethylene glycol to the iridium tantalum oxide coating solution in the present invention, the surface of the titanium anode presents the effects of high dispersion, homogenization, high specific surface area and refined grains, and a uniform three-dimensional porous nanoparticle morphology is generated.

[0035] The following tests were carried out on the strengthening electrolysis life of the above Examples 1-4 and Comparative Examples 1-7: The titanium anode with an iridium tantalum coating was processed into a sample with an electrode area of 1 cm 2 , a pure titanium sheet was used as the cathode, the electrode spacing was 1 cm, and the current density was 5 A / cm 2 . The temperature was controlled at 40 °C, and in an electrolytic solution of 20wt% H 2 SO 4 , the time experienced when the electrolysis voltage increased by 5 V relative to the initial value of electrolysis was the strengthening life of the electrode. The obtained strengthening electrolysis life is shown in Table 1, and the variation curve of the cell voltage with time is as Figure 4 shown.

[0036] Table 1 Strengthening electrolysis life of Examples 1-4 and Comparative Examples 1-7 Sample Surfactant <![CDATA[Strengthened electrolysis life / kAh m -2 > Example 1 Polyacrylamide 117800 Example 2 Polyethylene glycol 100700 Example 3 Polyacrylamide 97500 Example 4 Polyacrylamide 100350 Comparative Example 1 None 89340 Comparative Example 2 Sodium dodecyl sulfate 64500 Comparative Example 3 Cetyl dimethyl benzyl ammonium chloride 66250 Comparative Example 4 Dodecyl dimethyl betaine 46760 Comparative Example 5 Isopropanolamine 77230 Comparative Example 6 Polyvinyl alcohol 56150 Comparative Example 7 Polyvinylpyrrolidone 60900 It can be seen from Table 1 and Figure 4 that by comparing Examples 1-4 with Comparative Example 1, it can be known that adding polyacrylamide or polyethylene glycol to the iridium tantalum oxide coating solution can improve the service life of the titanium anode, which is attributed to the fact that the surface of the titanium anode in the present invention has a uniform three-dimensional porous nanoparticle morphology (as shown in Figure 1 a-h). The specific reason is: At appropriate low concentrations, polyacrylamide solution can be regarded as a network structure. The structural units of polyacrylamide contain amide groups, which are prone to forming hydrogen bonds. The mechanical entanglement between chains and hydrogen bonds together form network nodes, which endow it with good water solubility and high chemical activity. When the IrO 2 -Ta 2 O 5 -polyacrylamide coating solution is evenly coated on a titanium substrate containing an intermediate layer, this network structure provides a very good template. When pyrolyzed by calcination, polyacrylamide reacts with air and escapes in the form of gas. Under the action of oxygen, iridium chlorate and tantalum chloride form IrO 2 -Ta 2 O 5 , and well maintains the three-dimensional porous network morphology.

[0037] Liquid polyethylene glycol can be miscible with water in any proportion. When the polyethylene glycol solution reaches saturated adsorption, polyethylene glycol molecules are closely and regularly oriented on the surface of the aqueous solution, and a monomolecular film covers the surface of water. The formed moisture retention barrier can prevent water evaporation, thereby improving the wettability of the coating solution and enhancing the uniformity of the iridium content on the anode plate. In addition, any decomposition products of polyethylene glycol are volatile and will not form hard shells or slime-like precipitates.

[0038] In summary, adding polyacrylamide or polyethylene glycol to the iridium tantalum oxide coating solution improves the dispersion and stability of the active components on the surface of the titanium substrate, significantly enhances the electrochemical activity and service life of the coating catalyst on the surface of the titanium anode. In particular, the enhanced electrolysis service life of Example 1 is 31.9% higher than that of Comparative Example 1.

[0039] Comparing Example 1 with Examples 3 and 4, it can be seen that as the amount of polyacrylamide increases, the surface of the iridium tantalum coating changes from three-dimensional pores to large-area cracks. Although a relatively high specific surface area is retained to a certain extent, the coating with large-area cracks is prone to peeling off under the action of high current, thereby reducing its service life; when the amount is reduced, polyacrylamide is unevenly dispersed in the iridium tantalum oxide coating solution. Most of the iridium tantalum coatings appear in a three-dimensional porous morphology, but some IrO 2 crystalline grains can still be seen, indicating that by controlling the appropriate amount of polyacrylamide, the morphological structure of the iridium tantalum oxide coating on the titanium anode can be optimized to have appropriate pore sizes and excellent electrochemical activity and long service life.

[0040] Comparing Comparative Examples 2 to 7 with Comparative Example 1, it can be seen that adding other surfactants reduces the service life and electrochemical activity of the titanium anode instead, which can also be confirmed from the SEM images ( Figure 2 e-p and Figure 3 a-l), compared with the microscopic morphology of Comparative Example 1 ( Figure 2a-d), IrO 2 -Ta 2 O 5 Cracks appeared on the surface of the catalytic coating; during the oxygen evolution reaction, these cracks would cause the coating to peel off and the titanium substrate to passivate, thereby reducing its lifespan. This indicates that not any surfactant can achieve the effect of optimizing the iridium tantalum oxide coating.

[0041] The present invention has been described exemplarily in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-mentioned manner. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A surfactant-modified titanium anode coating, characterized in that: The invention comprises an iridium tantalum oxide coating to which a surfactant is added, wherein the surfactant is polyacrylamide or polyethylene glycol; and the dosage of the surfactant is 30-70% of the critical micelle concentration thereof.

2. The surfactant-modified titanium anode coating according to claim 1, characterized in that: The modified titanium anode coating is IrO2-Ta2O5-polyacrylamide coating or IrO2-Ta2O5-polyethylene glycol coating.

3. The surfactant-modified titanium anode coating according to claim 1, characterized in that: The iridium content in the modified titanium anode coating is 18-28 g / m 2 .

4. A method for preparing a surfactant-modified titanium anode coating according to any one of claims 1 to 3, characterized in that: The steps include: S1. preparing active iridium tantalum oxide coating solution for titanium anode; S2, uniformly mixing the surfactant and the active iridium tantalum oxide coating solution to obtain an iridium tantalum oxide coating solution containing the surfactant; S3, depositing an iridium tantalum oxide coating solution containing a surfactant on a titanium substrate containing an intermediate layer by a deposition method; S4, repeating the deposition operation in step S3 until the iridium content in the iridium-tantalum oxide coating reaches the standard, thus obtaining the surfactant-modified titanium anode coating.

5. The method for preparing a surfactant-modified titanium anode coating according to claim 4, characterized in that: In step S1, the molar ratio of iridium to tantalum in the active iridium tantalum oxide coating solution is 7:

3.

6. The method for preparing a surfactant-modified titanium anode coating according to claim 4, characterized in that: In step S2, the specific operation of mixing uniformly is: first magnetic stirring for 0.5-2 h, and then ultrasonic dispersion for 0.5-2 h.

7. The method for preparing a surfactant-modified titanium anode coating according to claim 4, characterized in that: In step S3, the mass of the iridium tantalum oxide coating liquid containing a surfactant is 15-25 g / m 2 .

8. The method for preparing a surfactant-modified titanium anode coating according to claim 4, characterized in that: In step S3, the deposition method is: uniformly coating an iridium tantalum oxide coating liquid containing a surfactant onto a titanium substrate containing an intermediate layer, drying at room temperature, and then oxidizing in a trolley furnace at 480-550° C. for 20-60 min.

9. The method for preparing a surfactant-modified titanium anode coating according to claim 4, characterized in that: In step S3, the titanium substrate is a titanium plate that has been sandblasted, shaped, pickled and etched.

10. An application of a surfactant-modified titanium anode coating, characterized in that: The titanium anode coating modified by the surfactant described in any one of claims 1 to 3 is used as a catalyst for the anode reaction of electrolyzing water.

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