阅读说明：本技术 一种长寿命钛基氧化锡阳电极及其制备方法和应用 (Long-life titanium-based tin oxide positive electrode and preparation method and application thereof ) 是由 陈阿青 梁轻 孔哲 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种长寿命钛基氧化锡阳电极及其制备方法和应用。该电极是通过在钛基底上依次沉积金属钽涂层、Sb掺杂氧化锡涂层得到。该电极不仅具有很长的使用寿命,高析氧电位～2.0V(参比标氢电极电位),而且还具有良好的导电性能。采用该阳电极进行电化学降解治理工业污水,能够去除COD和氨氮。(The invention discloses a long-life titanium-based tin oxide anode electrode and a preparation method and application thereof. The electrode is obtained by sequentially depositing a metal tantalum coating and an Sb-doped tin oxide coating on a titanium substrate. The electrode not only has long service life and high oxygen evolution potential of 2.0V (reference standard hydrogen electrode potential), but also has good conductivity. The anode electrode is adopted to carry out electrochemical degradation treatment on industrial sewage, and COD and ammonia nitrogen can be removed.)

1. The long-life titanium-based tin oxide anode electrode is characterized by comprising a titanium substrate, a metal tantalum layer and an Sb-doped tin oxide layer from bottom to top in sequence, wherein the oxygen evolution potential of the long-life titanium-based tin oxide anode electrode is 1.8-2.1V; wherein the Sb doping molar concentration in the Sb doping tin oxide layer is controlled to be 2-10 mol%.

2. The long life titanium-based tin oxide anode electrode of claim 1, wherein said tantalum metal layer has a thickness of 5-20 μm.

3. A preparation method of a long-life titanium-based tin oxide anode electrode is characterized by comprising the following steps:

s1, cleaning the surface of the titanium substrate;

s2, depositing a layer of metal tantalum layer on the upper surface of the titanium substrate cleaned in the step 1 to obtain a metal tantalum layer with the required thickness;

s3, mixing the tin salt solution with the antimony salt solution to obtain a precursor solution simultaneously containing tin and antimony;

s4, coating the precursor solution obtained in the step 3 on the upper surface of the metal tantalum layer obtained in the step 2, sequentially drying and calcining, cooling to room temperature after calcining, and repeating the steps for multiple times to obtain the antimony-doped tin oxide coating, so that the long-life titanium-based tin oxide anode containing the tantalum intermediate layer is obtained.

4. The method for preparing a long life titanium-based tin oxide anode electrode as claimed in claim 3, wherein the technique for depositing the tantalum metal is a DC magnetron sputtering or RF magnetron sputtering technique.

5. The method for preparing a long life titanium-based tin oxide anode electrode as claimed in claim 3, wherein the precursor solution containing both tin and antimony has a pH of 5 to 6.

6. The method for preparing a long life titanium-based tin oxide anode electrode as claimed in claim 3, wherein said precursor solution containing tin and antimony is applied by spraying or brushing on the surface of the titanium substrate.

7. The method of claim 3 wherein said drying is at a temperature of about 80-150 ℃.

8. The method of claim 3 wherein said calcining temperature is above 450 ℃.

9. The method of claim 7 wherein said calcining temperature is 550 ℃.

10. Use of a long life titanium-based tin oxide anode electrode as claimed in claim 1 or 2 for electrochemical treatment of organic and ammonia nitrogen in industrial wastewater.

Technical Field

The invention belongs to the technical field of positive electrodes for treating wastewater by electrochemical oxidation, and particularly relates to a long-life titanium-based tin oxide positive electrode as well as a preparation method and application thereof.

Background

Physical precipitation and biochemical processes are the main methods for treating current industrial wastewater. However, most of industrial wastewater has high salinity and organic matter contentHigh content, high ammonia nitrogen content, high biological toxicity and poor biodegradability, such as wastewater from fine chemical industry, wastewater from biological pharmacy, wastewater from medical intermediate, and wastewater from coal coking. This results in physical precipitation and biochemical processes that make it difficult to effectively treat such waste waters. The electrochemical advanced oxidation technology can generate hydroxyl free radicals and active oxygen particles through water electrolysis, can directly or indirectly oxidize and decompose organic matters in water into carbon dioxide and water, and can oxidize and decompose ammonia nitrogen in water into nitrogen and water without secondary pollution, thereby being a green and environment-friendly sewage treatment technology. In the process of treating industrial sewage by electrochemical advanced oxidation, the electrocatalytic performance of the anode electrode material plays a key role. For the electrode with higher oxygen evolution potential, the electrochemical oxidation performance is higher, the types of the organic matters subjected to oxidative decomposition are wider, the current efficiency is higher, and the energy consumption for treating the industrial wastewater by the electrochemical advanced oxidation is lower. The traditional anode electrode of antimony doped tin oxide has higher oxygen evolution potential, about 2.0V (reference standard hydrogen electrode potential), and also has the advantage of low cost, and is the most promising anode electrode. However, antimony doped tin oxide anodes have the disadvantage of short service life and cannot be used industrially for long periods. Although some techniques have been used to extend the useful life of tin oxide anodes, such as TiO formation on the surface of a Ti substrate₂Nanotubes, then Sb is doped with SnO₂Filled into TiO₂Nanotube medium (Environmental Science)&Technology,2009,43(5): 1480-1486) by subjecting the surface of a titanium substrate to a hydrogenation treatment to form a TiHx intermediate layer (Industrial)&Engineering Chemistry Research,2014,53: 3898-. However, these TiO compounds₂The poor conductivity properties of the nanotubes and the TiHx intermediate layer reduce the conductivity of the tin oxide anode.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a long-life titanium-based tin oxide anode electrode. The anode electrode is a titanium-based tin oxide anode electrode obtained by depositing a metal tantalum coating on a titanium substrate and then depositing an Sb-doped tin oxide coating on the metal tantalum coating. The electrode not only has long service life, but also keeps the high oxygen evolution potential of 1.8-2.1V (reference standard hydrogen electrode potential), and has good conductivity.

In order to achieve the technical purpose, the technical means of the invention is as follows:

the invention provides a long-life titanium-based tin oxide anode, which sequentially comprises a titanium substrate, a metal tantalum layer and an Sb-doped tin oxide layer from bottom to top; wherein the Sb doping molar concentration (mol%) in the Sb doping tin oxide layer is controlled to be 2-10%.

The oxygen evolution potential of the titanium-based tin oxide anode electrode is between 1.8 and 2.1V (reference standard hydrogen electrode potential).

Preferably, the thickness of the metal tantalum layer is 5-20 um.

Another object of the present invention is to provide a method for preparing the above tin oxide anode electrode having a long lifetime, which comprises the steps of:

s1 cleaning the surface of a titanium substrate

Carrying out sand blasting treatment on the surface of a titanium matrix, then carrying out acid washing and alkali washing on the surface of the titanium matrix subjected to sand blasting to remove organic pollutants such as a titanium dioxide film and oil stains on the surface, cleaning the titanium matrix by using an organic solvent and deionized water, and finally quickly drying the titanium matrix by using nitrogen;

s2, depositing a layer of metal tantalum layer on the upper surface of the titanium substrate cleaned in the step 1 to obtain a metal tantalum layer with the required thickness;

s3, mixing the tin salt solution with the antimony salt solution to obtain a precursor solution simultaneously containing tin and antimony;

the tin salt solution is a mixed solution with tin salt as a solute and an organic solution as a solvent;

the antimonium salt solution is a mixed solution with antimonium salt as a solute and an organic solution as a solvent;

s4, coating the precursor solution obtained in the step 3 on the upper surface of the metal tantalum layer obtained in the step 2, sequentially drying and calcining, cooling to room temperature after calcining, and repeating the steps for 10-20 times to obtain an antimony-doped tin oxide coating, so that the long-life titanium-based tin oxide anode electrode containing the tantalum intermediate layer is obtained.

Preferably, the carborundum with the grain size of more than 100 meshes is selected in the sand blasting treatment of the titanium substrate surface.

Preferably, the organic pollutants on the surface of the titanium substrate are removed by using a solvent or an alkali solution, such as alcohol, sodium hydroxide and the like.

Preferably, the titanium dioxide film on the surface of the titanium substrate is removed by etching the titanium substrate with boiled acid, such as hydrochloric acid, oxalic acid, etc.

Preferably, the technology for depositing the metal tantalum is a direct-current magnetron sputtering technology or a radio-frequency magnetron sputtering technology.

Preferably, the tin salt is a crystalline compound of tin chloride soluble in an organic solvent.

Preferably, the pH value of the precursor solution containing the tin salt and the antimony salt is 5-6, so that the antimony trichloride is completely dissolved in water, and the solution is clear and uniform.

Preferably, the organic solution is a mixed solution of anhydrous ethanol and Isopropanol (IPA), wherein the volume content of the IPA is 10-30%, which ensures that the organic solution has certain viscosity and reduces the generation of cracks in the subsequent drying and sintering processes of the coating.

Preferably, the precursor solution containing tin and antimony is applied to the surface of the titanium substrate by spraying or brushing.

Preferably, the drying temperature is 80-150 ℃.

Preferably, the calcination temperature is 450 ℃ or higher, preferably 550 ℃.

The invention also aims to provide application of the tin oxide anode electrode with long service life in electrochemical treatment of industrial sewage and removal of organic matters and ammonia nitrogen in the industrial sewage.

The invention has the beneficial effects that: the invention provides a long-life titanium-based tin oxide anode and a preparation method thereof, wherein a metal tantalum layer is deposited between a titanium substrate and an antimony-doped tin oxide coating, so that the conductivity of the tin oxide electrode is ensured, and the service life of the tin oxide anode is greatly prolonged. The anode electrode is adopted to carry out electrochemical degradation treatment on industrial sewage, and COD and ammonia nitrogen can be removed.

Drawings

FIG. 1 is a scanning electron photograph of a tin oxide anode electrode in an example of the present invention.

FIG. 2 is a graph of the oxygen evolution potential of a tin oxide anode electrode in an example of the present invention.

FIG. 3 is a graph of enhanced life test of tin oxide electrodes in accordance with an embodiment of the present invention.

Detailed Description

The following is a detailed description of the embodiments of the present invention, which is implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific procedures are given, but the scope of the present invention is not limited to the following embodiments.

Examples 1, 1,

1. Selecting a titanium plate with the thickness of 2mm, and performing sand blasting treatment on two surfaces of the titanium plate through a sand blasting process respectively, wherein the size of sand grains is 200 meshes. And (3) placing the titanium plate after sand spraying into deionized water, ultrasonically cleaning for 20 minutes, then placing the titanium plate into an oxalic acid solution with the mass concentration of 10%, boiling, corroding for 1 hour, sequentially placing the corroded titanium plate into alcohol and deionized water, ultrasonically cleaning for 10 minutes, and finally blowing the titanium plate dry by nitrogen for later use.

2. Putting the titanium plate obtained in the step 1 into a vacuum chamber of a magnetron sputtering instrument, adopting a metal tantalum target as a sputtering target material, vacuumizing the vacuum chamber by using a vacuum pump, and when the background air pressure in the vacuum chamber is lower than 10^-4And when the thickness of the film is more than 5 microns, stopping coating, and taking out the titanium plate coated with the tantalum film.

3. 2.0g SnCl is weighed by an electronic balance₄·5H₂Dissolving O and 0.06g of antimony trichloride into alcohol and IPA solution, wherein the concentration of IPA is 10%, dropwise adding a few drops of hydrochloric acid to ensure that the pH value of the solution is 5.0, and then continuously stirring for 30min at a constant temperature of 25 ℃ by using a magnetic heating stirrer to fully disperse the solution to obtain uniform and transparent solution.

4. Uniformly coating the solution obtained in the step (3) on the tantalum layer on the titanium sheet obtained in the step (2), and then putting the tantalum layer into a 120-DEG oven for drying; putting the dried titanium sheet into a sintering furnace, and sintering at 550 ℃ for 10 minutes; and finally, taking out the titanium sheet and naturally cooling to room temperature. Repeating the steps for 15-20 times to obtain the titanium-based tin oxide anode.

FIG. 1 is a scanning electron photograph of a tin oxide anode electrode in an example of the present invention.

FIG. 2 is a graph of the oxygen evolution potential of a tin oxide anode electrode in an example of the present invention.

Examples 2,

1. Selecting a titanium plate with the thickness of 2mm, and performing sand blasting treatment on two surfaces of the titanium plate respectively through a sand blasting process, wherein the size of sand grains is 300 meshes. And (3) placing the titanium plate after sand spraying into deionized water, ultrasonically cleaning for 20 minutes, then placing the titanium plate into a hydrochloric acid solution with the mass concentration of 13%, boiling, corroding for 30 hours, sequentially placing the corroded titanium plate into the deionized water, alcohol and the deionized water, respectively ultrasonically cleaning for 10 minutes, and finally blowing the titanium plate dry by nitrogen for later use.

2. Putting the titanium plate obtained in the step 1 into a vacuum chamber of a magnetron sputtering instrument, adopting a metal tantalum target as a sputtering target material, vacuumizing the vacuum chamber by using a vacuum pump, and when the background air pressure in the vacuum chamber is lower than 10^-4And when the thickness of the film is more than 5 microns, stopping coating, and taking out the titanium plate coated with the tantalum film for later use.

3. 2.0g SnCl is weighed by an electronic balance₄·5H₂Dissolving O and 0.1g of antimony trichloride into alcohol and IPA solution, wherein the concentration of IPA is 15%, dropwise adding a few drops of hydrochloric acid to ensure that the pH value of the solution is 6.0, and then continuously stirring for 30min at a constant temperature of 25 ℃ by using a magnetic heating stirrer to fully disperse the solution to obtain a uniform and transparent solution.

4. Uniformly coating the solution obtained in the step (3) on the tantalum layer on the titanium sheet obtained in the step (2), and then putting the tantalum layer into a 120-DEG oven for drying; putting the dried titanium sheet into a sintering furnace, and sintering at 500 ℃ for 10 minutes; and finally, taking out the titanium sheet and naturally cooling to room temperature. Repeating the steps for 15-20 times to obtain the titanium-based tin oxide anode.

Examples 3,

1. Selecting a titanium plate with the thickness of 2mm, and performing sand blasting treatment on two surfaces of the titanium plate through a sand blasting process respectively, wherein the size of sand grains is 200 meshes. And (3) placing the titanium plate after sand spraying into deionized water, ultrasonically cleaning for 20 minutes, then placing the titanium plate into a hydrochloric acid solution with the mass concentration of 13%, boiling, corroding for 30 hours, sequentially placing the corroded titanium plate into the deionized water, alcohol and the deionized water, respectively ultrasonically cleaning for 10 minutes, and finally blowing the titanium plate dry by nitrogen for later use.

2. Putting the titanium plate obtained in the step 1 into a vacuum chamber of a magnetron sputtering instrument, adopting a metal tantalum target as a sputtering target material, vacuumizing the vacuum chamber by using a vacuum pump, and when the background air pressure in the vacuum chamber is lower than 10^-4And when the thickness of the film is more than 10 microns, stopping coating, and taking out the titanium plate coated with the tantalum film for later use.

3. 2.0g SnCl is weighed by an electronic balance₄·5H₂Dissolving O and 0.1g of antimony trichloride into alcohol and IPA solution, wherein the concentration of IPA is 20%, dropwise adding a few drops of hydrochloric acid to ensure that the pH value of the solution is 6.0, and then continuously stirring for 30min at a constant temperature of 25 ℃ by using a magnetic heating stirrer to fully disperse the solution to obtain uniform and transparent solution.

4. Uniformly coating the solution obtained in the step (3) on the tantalum layer on the titanium sheet obtained in the step (2), and then putting the tantalum layer into a 120-DEG oven for drying; putting the dried titanium sheet into a sintering furnace, and sintering at 500 ℃ for 10 minutes; and finally, taking out the titanium sheet and naturally cooling to room temperature. Repeating the steps for 15-20 times to obtain the titanium-based tin oxide anode.

FIG. 3 is a graph of enhanced life test of a tin oxide electrode in an example of the present invention, under the following test conditions: the electrolyte solution is sulfuric acid with the concentration of 3mol/L, and the current density is 100 mA-cm²Ti/Sb-SnO2 is a tin oxide electrode not containing a Ta intermediate layer, Ti/Ta/Sb-SnO₂Is a tin oxide electrode containing a Ta interlayer in the examples of the invention.

Details not described in the present specification are known to those skilled in the art. The above-described embodiments are not intended to limit the present invention, and any modifications and changes made thereto within the spirit and scope of the claims are included in the scope of the present invention.