Ti4o7 electrode, method for preparing the same and use thereof

Abstract

This invention relates to the field of wastewater treatment, and discloses a Ti4O7 electrode, its preparation method, and its applications. The preparation method of the Ti4O7 electrode of this invention includes: 1) coating a substrate with a solution containing titanium dioxide, a dispersant, a thickener, a co-solvent, and polyacrylic acid or its salt, followed by drying, so that the titanium dioxide film is in a gel state; 2) subjecting the substrate-gel composite obtained in step 1) to a first annealing to obtain a TiO2-substrate film; 3) subjecting the TiO2-substrate film obtained in step 2) to a second annealing in a hydrogen atmosphere. According to the method of this invention, it has low cost, and the Ti4O7 electrode obtained by this method has higher electrocatalytic performance and stability.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, specifically to a Ti4O7 electrode, its preparation method, and its application. Background Technology

[0002] The treatment of high-salinity organic wastewater has always been a major challenge in industrial wastewater treatment. Electrochemical advanced oxidation, through redox reactions occurring on the electrode surface, directly or indirectly oxidizes and degrades organic pollutants in water bodies. It has advantages such as high degradation efficiency, low secondary pollution, and strong controllability, and is widely used in the treatment of dye wastewater. Ti4O7 electrodes, with their strong conductivity, strong corrosion resistance, high oxygen evolution potential, and relatively low cost, have attracted widespread attention and are a promising electrode material.

[0003] CN112340817A discloses a nano-titanium oxide catalytic electrode material and its preparation method. In this invention, the titanium oxide powder is prepared by molten salt synthesis, and the electrode material preparation method combines nano-dispersion, vacuum sputtering, and screen printing technologies to prepare a high-purity, high-stability nano-Ti4O7 catalytic electrode material. Although a high-purity Ti4O7 catalytic electrode material is synthesized, the cost is high.

[0004] Although it is cheaper than BDD anode materials, the preparation cost is still relatively high, which affects its further application. There is an urgent need to develop a low-cost method for preparing Ti4O7 electrodes. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of high cost of Ti4O7 electrodes in the prior art, and to provide a low-cost Ti4O7 electrode, its preparation method and application, and the Ti4O7 electrode obtained by this method has higher electrocatalytic performance and stability.

[0006] To achieve the above objectives, the present invention provides a method for preparing a Ti4O7 electrode, wherein the method includes the following steps:

[0007] 1) The step of coating a substrate with a solution containing titanium dioxide, dispersant, thickener, cosolvent and polyacrylic acid or its salt and then drying it so that the titanium dioxide film is in a gel state.

[0008] 2) The substrate gel composite obtained in step 1) is subjected to a first annealing to obtain a TiO2-substrate film;

[0009] 3) The TiO2-substrate film obtained in step 2) is subjected to a second annealing step in a hydrogen atmosphere.

[0010] Preferably, in the solution, the content of titanium dioxide is 3-30% by weight, the content of dispersant is 5-15% by weight, the content of thickener is 0.1-2% by weight, the content of cosolvent is 0.1-2% by weight, and the content of polyacrylic acid or its salt is 0.1-3% by weight; more preferably, the content of titanium dioxide is 5-25% by weight, the content of dispersant is 8-12% by weight, the content of thickener is 1-2% by weight, the content of cosolvent is 0.5-1% by weight, and the content of polyacrylic acid or its salt is 1-2% by weight.

[0011] Preferably, the solvent in the solution is water, more preferably deionized water.

[0012] Preferably, the dispersant is polyvinyl alcohol and / or polyvinyl butyral, more preferably polyvinyl butyral.

[0013] Preferably, the thickener is glycerol and / or hydroxypropyl methylcellulose, more preferably hydroxypropyl methylcellulose.

[0014] Preferably, the co-solvent is N-methylpyrrolidone and / or N,N-dimethylformamide, more preferably N,N-dimethylformamide.

[0015] Preferably, the salt of the polyacrylic acid is sodium polyacrylate.

[0016] Preferably, in step 1), the solution is coated onto the substrate using a dip-coating method.

[0017] Preferably, the substrate is selected from ceramic film, titanium plate or niobium plate.

[0018] Preferably, in step 1), the drying temperature is 5-45℃ and the drying time is 12-48h.

[0019] Preferably, in step 2), the conditions for the first annealing include: an annealing temperature of 500-900℃ and an annealing time of 2-10h.

[0020] Preferably, in step 3), the conditions for the second annealing include: an annealing temperature of 500-900℃ and an annealing time of 2-10h.

[0021] According to a second aspect of the present invention, a Ti4O7 electrode prepared by the method provided in the first aspect of the present invention is provided.

[0022] According to a third aspect of the present invention, the application of the Ti4O7 electrode prepared by the method provided in the first aspect of the present invention in the treatment of saline organic wastewater is provided.

[0023] Through the above technical solution, the raw materials used in the preparation method of the Ti4O7 electrode of the present invention are low in cost and easy to obtain, and the Ti4O7 electrode obtained by this method has higher electrocatalytic performance and stability. Attached Figure Description

[0024] Figure 1 This is the XRD pattern of the Ti4O7 electrode sheet prepared in Example 1. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] According to a first aspect of the present invention, a method for preparing a Ti4O7 electrode is provided, wherein the method includes the following steps:

[0027] 1) The step of coating a substrate with a solution containing titanium dioxide, dispersant, thickener, cosolvent and polyacrylic acid or its salt and then drying it so that the titanium dioxide film is in a gel state.

[0028] 2) The substrate gel composite obtained in step 1) is subjected to a first annealing to obtain a TiO2-substrate film;

[0029] 3) The TiO2-substrate film obtained in step 2) is subjected to a second annealing step in a hydrogen atmosphere.

[0030] According to the method of the present invention, preferably, the solution contains 3-30% by weight of titanium dioxide, 5-15% by weight of dispersant, 0.1-2% by weight of thickener, 0.1-2% by weight of cosolvent, and 0.1-3% by weight of polyacrylic acid or its salt; more preferably, the solution contains 5-25% by weight of titanium dioxide, 8-12% by weight of dispersant, 1-2% by weight of thickener, 0.5-1% by weight of cosolvent, and 1-2% by weight of polyacrylic acid or its salt.

[0031] Specific examples of the content of the dispersant in the solution include, for example, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, etc., as well as the range formed by any two of the above values.

[0032] Specific examples of the content of the dispersant in the solution include, for example, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, etc., as well as any range of any two of the above values.

[0033] Specific examples of the content of the thickener in the solution include, for example, 0.1 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, etc., as well as any range of any two of the above values.

[0034] Specific examples of the content of the co-solvent in the solution include, for example, 0.1 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, etc., as well as any range of any two of the above values.

[0035] Specific examples of the content of the polyacrylic acid or its salt in the solution include, for example, 0.1 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, 3 wt%, etc., as well as any range formed by any two of the above values.

[0036] In this invention, the dispersant plays the role of dispersing titanium dioxide on the substrate surface. By adding the dispersant within the above range and using it in combination with other components, it is possible to effectively prevent uneven film layer on the electrode plate surface, thereby improving the electrocatalytic performance and stability of the obtained electrode.

[0037] In this invention, preferably, the dispersant is polyvinyl alcohol and / or polyvinyl butyral; more preferably, the dispersant is polyvinyl butyral.

[0038] In a particularly preferred embodiment of the invention, the dispersant is polyvinyl butyral, which can significantly improve the electrocatalytic performance and stability of the obtained electrode.

[0039] In this invention, the thickener plays a role in thickening. By adding the thickener within the above-mentioned range and using it in combination with other components, it is possible to effectively prevent membrane detachment, thereby improving the electrocatalytic performance and stability of the obtained electrode.

[0040] In this invention, preferably, the thickener is glycerol and / or hydroxypropyl methylcellulose; more preferably, the thickener is hydroxypropyl methylcellulose.

[0041] In a particularly preferred embodiment of the invention, the thickener is hydroxypropyl methylcellulose, which can significantly improve the electrocatalytic performance and stability of the obtained electrode.

[0042] In this invention, the co-solvent plays a role in efficiently dissolving titanium dioxide and organic matter. By adding the co-solvent within the above-mentioned range and using it in combination with other components, the solution can be mixed evenly, thereby improving the electrocatalytic performance and stability of the obtained electrode.

[0043] In this invention, preferably, the co-solvent is N-methylpyrrolidone and / or N,N-dimethylformamide; more preferably, the co-solvent is N,N-dimethylformamide.

[0044] In a preferred embodiment of the present invention, the co-solvent is N,N-dimethylformamide, which can further improve the electrocatalytic performance and stability of the obtained electrode.

[0045] In this invention, the polyacrylic acid or its salt is used as an electrode modification material. By forming strong hydrogen bonds with the electrode material and in combination with other components, the electrocatalytic performance and stability of the obtained electrode can be significantly improved.

[0046] As a salt of the polyacrylic acid, sodium polyacrylate and / or potassium polyacrylate can be used, preferably sodium polyacrylate.

[0047] In a preferred embodiment of the invention, polyacrylic acid is used, thereby further improving the electrocatalytic performance and stability of the resulting electrode.

[0048] According to the method of the present invention, the solvent in the solution can be water, preferably deionized water.

[0049] In this invention, the solvent is the remainder in the solution.

[0050] According to the method of the present invention, in step 1), the solution can be coated onto the substrate using conventional methods in the art, such as one or more of spraying, dip coating, evaporation coating, and sputtering coating. Preferably, the coating is a dip coating method.

[0051] According to the method of the present invention, when using the dip-dip method, the dip time is preferably 5-20 seconds, and more preferably 10-15 seconds from the perspective of further improving electrocatalytic performance and stability.

[0052] In a particularly preferred embodiment of the invention, when using the dip-in method, the dip time is 15 seconds, thereby further improving the electrocatalytic performance and stability.

[0053] According to the method of the present invention, the substrate can be any of the anode substrates commonly used in the art. Preferably, the substrate is selected from ceramic films, titanium plates or niobium plates; more preferably, the substrate is selected from ceramic films.

[0054] In this invention, by making the substrate a ceramic film, the ceramic film electrode has the advantages of strong resistance to chemical corrosion, stability in harsh chemical environments, and extended service life.

[0055] According to the method of the present invention, in step 1), the drying causes the titanium dioxide film to exhibit a gel state. The drying conditions are only required to achieve a gel state in the titanium dioxide film. Preferably, in step 1), the drying temperature is 5-45°C and the drying time is 12-90 h; more preferably, in step 1), the drying temperature is 10-35°C and the drying time is 20-75 h.

[0056] In a preferred embodiment of the present invention, the drying temperature is room temperature (e.g., 10-35°C), and the drying time is, for example, 24-72 hours.

[0057] According to the method of the present invention, preferably, in step 2), the conditions for the first annealing include: an annealing temperature of 500-900°C and an annealing time of 2-10h; more preferably, the conditions for the first annealing include: an annealing temperature of 600-800°C and an annealing time of 2-5h.

[0058] There are no particular limitations on the equipment used for the first annealing; for example, the first annealing can be carried out in a high-temperature furnace.

[0059] According to the method of the present invention, preferably, in step 3), the conditions for the second annealing include: an annealing temperature of 500-900°C and an annealing time of 2-10h; more preferably, the conditions for the second annealing include: an annealing temperature of 600-800°C and an annealing time of 2-5h.

[0060] There are no particular limitations on the equipment used for the second annealing; for example, the second annealing can be carried out in a tube furnace.

[0061] According to the method of the present invention, a Ti4O7 porous membrane electrode can be obtained by the above method. The preparation cost is low, and the Ti4O7 electrode obtained by this method has higher electrocatalytic performance and stability.

[0062] According to a second aspect of the present invention, a Ti4O7 electrode prepared by the method described in the first aspect of the present invention is provided.

[0063] According to a third aspect of the present invention, the application of the Ti4O7 electrode prepared by the method described in the first aspect of the present invention in the treatment of saline organic wastewater is provided.

[0064] For example, saline organic wastewater generated during the molecular sieve production process can be cited as an example of such saline organic amine wastewater.

[0065] The present invention will be described in detail below by comparing it with the following embodiments, but the present invention is not limited to the following embodiments.

[0066] Unless otherwise specified, all materials used in the following examples and comparative examples are commercially available products.

[0067] Example 1

[0068] The coating substrate of this electrode material is a ceramic diaphragm.

[0069] 1) Prepare a TiO2 solution (the remainder is deionized water as a solvent). Add 10g polyvinyl alcohol, 5g titanium dioxide, 1.5g glycerol, 1g N-methylpyrrolidone, and 2g polyacrylic acid to every 100g of solution. After the chemicals are added, stir thoroughly.

[0070] 2) A layer of titanium dioxide sol film is coated on the ceramic film substrate using the dip-coating method, and the immersion time is 5 seconds.

[0071] 3) Dry the membrane at room temperature for 24 hours to allow the ceramic membrane coated with titanium dioxide to exhibit a gel state.

[0072] 4) The sample was placed in a high-temperature furnace for annealing at 600℃ for 3 hours. After cooling, TiO2-ceramic film was obtained.

[0073] 5) The prepared TiO2-ceramic film was placed in a tube furnace and annealed in a hydrogen atmosphere at a temperature of 600℃ for 4 hours. After cooling, the Ti4O7 porous film electrode A1 was obtained.

[0074] Figure 1 This is the XRD pattern of the Ti4O7 electrode sheet prepared in Example 1 (using a SmartLab X-ray diffractometer: Rigaku Corporation, Japan). Figure 1 It can be seen that Ti4O7 was formed on the surface of the electrode plate.

[0075] Example 2

[0076] The coating substrate for this electrode material is a titanium plate.

[0077] 1) Prepare a TiO2 solution (the remainder is deionized water as a solvent). Add 10g polyvinyl alcohol, 10g titanium dioxide, 1.5g glycerin, 1g N-methylpyrrolidone, and 2g polyacrylic acid to every 100g of solution. After the chemicals are added, stir thoroughly.

[0078] 2) A layer of titanium dioxide sol film is coated on the ceramic film substrate using the dip-coating method, and the immersion time is 10 seconds.

[0079] 3) Dry the membrane at room temperature for 48 hours to allow the ceramic membrane coated with titanium dioxide to exhibit a gel state.

[0080] 4) The sample was placed in a high-temperature furnace for annealing at 700℃ for 3 hours. After cooling, TiO2-ceramic film was obtained.

[0081] 5) The prepared TiO2-ceramic film was placed in a tube furnace and annealed in a hydrogen atmosphere at a temperature of 700℃ for 4 hours. After cooling, the Ti4O7 porous film electrode A2 was obtained.

[0082] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0083] Example 3

[0084] The coating substrate of this electrode material is a ceramic diaphragm.

[0085] 1) Prepare a TiO2 solution (the remainder is deionized water as a solvent). Add 10g polyvinyl alcohol, 5g titanium dioxide, 1.5g glycerol, 1g N-methylpyrrolidone, and 2g polyacrylic acid to every 100g of solution. After the chemicals are added, stir thoroughly.

[0086] 2) A layer of titanium dioxide sol film is coated on the ceramic film substrate using the dip-coating method, and the immersion time is 15 seconds.

[0087] 3) Dry the membrane at room temperature for 24 hours to allow the ceramic membrane coated with titanium dioxide to exhibit a gel state.

[0088] 4) The sample was placed in a high-temperature furnace for annealing at 600℃ for 3 hours. After cooling, TiO2-ceramic film was obtained.

[0089] 5) The prepared TiO2-ceramic film was placed in a tube furnace and annealed in a hydrogen atmosphere at a temperature of 600℃ for 4 hours. After cooling, the Ti4O7 porous film electrode A3 was obtained.

[0090] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0091] Example 4

[0092] The coating substrate for this electrode material is a titanium plate.

[0093] 1) Prepare a TiO2 solution (the remainder is deionized water as a solvent). Add 10g polyvinyl alcohol, 15g titanium dioxide, 1.5g glycerol, 1g N-methylpyrrolidone, and 2g polyacrylic acid to every 100mL of solution. After the chemicals are added, stir thoroughly.

[0094] 2) A layer of titanium dioxide sol film is coated on the ceramic film substrate using the dip-coating method, and the immersion time is 20 seconds.

[0095] 3) Dry the membrane at room temperature for 72 hours to allow the ceramic membrane coated with titanium dioxide to exhibit a gel state.

[0096] 4) The sample was placed in a high-temperature furnace for annealing at 800℃ for 3 hours. After cooling, TiO2-ceramic film was obtained.

[0097] 5) The prepared TiO2-ceramic film was placed in a tube furnace and annealed in a hydrogen atmosphere at a temperature of 800℃ for 4 hours. After cooling, the Ti4O7 porous film electrode A4 was obtained.

[0098] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0099] Example 5

[0100] The coating substrate for this electrode material is a titanium plate.

[0101] 1) Prepare a TiO2 solution (the remainder is deionized water as a solvent). Add 10g polyvinyl alcohol, 25g titanium dioxide, 1.5g glycerin, 1g N-methylpyrrolidone, and 2g polyacrylic acid to every 100g of solution. After the chemicals are added, stir thoroughly.

[0102] 2) A layer of titanium dioxide sol film is coated on the ceramic film substrate using the dip-coating method, and the immersion time is 20 seconds.

[0103] 3) Dry the membrane at room temperature for 48 hours to allow the ceramic membrane coated with titanium dioxide to exhibit a gel state.

[0104] 4) The sample was placed in a high-temperature furnace for annealing at 900℃ for 3 hours. After cooling, TiO2-ceramic film was obtained.

[0105] 5) The prepared TiO2-ceramic film was placed in a tube furnace and annealed in a hydrogen atmosphere at a temperature of 800℃ for 4 hours. After cooling, the Ti4O7 porous film electrode A5 was obtained.

[0106] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0107] Example 6

[0108] The procedure was carried out according to Example 1, except that polyvinyl alcohol was replaced with the same weight of polyvinyl butyral to obtain Ti4O7 porous membrane electrode A6.

[0109] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0110] Example 7

[0111] The procedure was carried out according to Example 1, except that glycerol was replaced with the same weight of hydroxypropyl methylcellulose to obtain Ti4O7 porous membrane electrode A7.

[0112] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0113] Example 8

[0114] The procedure was carried out according to Example 1, except that N-methylpyrrolidone was replaced with the same weight of N,N-dimethylformamide to obtain Ti4O7 porous membrane electrode A8.

[0115] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0116] Example 9

[0117] The procedure was carried out according to Example 1, except that polyacrylic acid was replaced with the same weight of sodium polyacrylate to obtain Ti4O7 porous membrane electrode A9.

[0118] Similar to Example 1, the XRD pattern of the Ti4O7 electrode sheet shows that Ti4O7 was formed on the surface of the electrode.

[0119] Comparative Example 1

[0120] The procedure was carried out according to Example 1, except that polyvinyl alcohol was replaced with the same weight of solvent to obtain Ti4O7 porous membrane electrode D1.

[0121] Comparative Example 2

[0122] The procedure was carried out according to Example 1, except that glycerol was replaced with the same weight of solvent to obtain Ti4O7 porous membrane electrode D2.

[0123] Comparative Example 3

[0124] The procedure was carried out according to Example 1, except that N-methylpyrrolidone was replaced with the same weight of solvent to obtain Ti4O7 porous membrane electrode D3.

[0125] Comparative Example 4

[0126] The procedure was carried out according to Example 1, except that polyacrylic acid was replaced with the same weight of solvent to obtain Ti4O7 porous membrane electrode D4.

[0127] Test Example 1

[0128] Please provide test results for the electrodes obtained using the examples and comparative cases in wastewater treatment. The test methods are as follows.

[0129] 1) Performance test of electrocatalytic oxidation of wastewater:

[0130] Electrocatalytic oxidation of organic amine wastewater (high-salt organic amine wastewater generated during molecular sieve production, COD 20000 mg / L, TDS 20 g / L) was performed using electrodes obtained in the examples and comparative examples, respectively, at a current density of 60 mA / cm². 2 After 12 hours of treatment, the COD value after electrocatalytic oxidation was measured, and the COD removal rate was calculated using the following formula:

[0131] COD removal rate = (COD before treatment - COD at test) / COD before treatment × 100%

[0132] The results are shown in Table 1.

[0133] 2) Stability test of electrocatalytic oxidation wastewater

[0134] Electrocatalytic oxidation of organic amine wastewater (high-salt organic amine wastewater generated during molecular sieve production, COD 20000 mg / L, TDS 20 g / L) was performed using the electrode plates obtained in the examples and comparative examples, respectively, at a current density of 60 mA / cm². 2 The treatment was carried out for 12 hours, and the COD value was measured. The treatment was repeated 10 times. The COD degradation rate on the 10th cycle and the initial decrease in electrocatalytic efficiency were used as the stability test method, as detailed below.

[0135] Calculate the COD removal rate using the following formula:

[0136] COD removal reduction efficiency = (1st COD degradation rate - 10th COD degradation rate) / 1st COD degradation rate × 100%

[0137] The results are shown in Table 1.

[0138] Table 1

[0139]

[0140] As can be seen from the table above, the Ti4O7 electrode prepared by the method of the present invention has higher electrocatalytic performance and stability.

[0141] By comparing Example 3 with Example 1, it can be seen that when using the dip-coating method, the electrocatalytic performance and stability of the obtained Ti4O7 electrode can be further improved by making the dip-coating time 10-15 seconds.

[0142] By comparing Example 6 with Example 1, it can be seen that using polyvinyl butyral as a dispersant can significantly improve the electrocatalytic performance and stability of the obtained Ti4O7 electrode.

[0143] By comparing Example 7 with Example 1, it can be seen that the use of hydroxypropyl methylcellulose as a thickener can significantly improve the electrocatalytic performance and stability of the obtained Ti4O7 electrode.

[0144] By comparing Example 8 with Example 1, it can be seen that using N,N-dimethylformamide as a cosolvent can further improve the electrocatalytic performance and stability of the obtained Ti4O7 electrode.

[0145] By comparing Example 9 with Example 1, it can be seen that by using polyacrylic acid, the electrocatalytic performance and stability of the obtained Ti4O7 electrode can be further improved compared with sodium polyacrylate.

[0146] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a Ti4O7 electrode, characterized in that, This method Includes the following steps, 1) The step of coating a substrate with a solution containing titanium dioxide, dispersant, thickener, cosolvent and polyacrylic acid or its salt and then drying it so that the titanium dioxide film is in a gel state. 2) The substrate gel composite obtained in step 1) is subjected to a first annealing to obtain a TiO2-substrate film; 3) The TiO2-substrate film obtained in step 2) is subjected to a second annealing step in a hydrogen atmosphere.

2. The method according to claim 1, wherein, In the solution, the content of titanium dioxide is 3-30% by weight, the content of dispersant is 5-15% by weight, the content of thickener is 0.1-2% by weight, the content of co-solvent is 0.1-2% by weight, and the content of polyacrylic acid or its salt is 0.1-3% by weight.

3. The method according to claim 1, wherein, The content of titanium dioxide is 5-25% by weight, the content of dispersant is 8-12% by weight, the content of thickener is 1-2% by weight, the content of cosolvent is 0.5-1% by weight, and the content of polyacrylic acid or its salt is 1-2% by weight.

4. The method according to any one of claims 1-3, wherein, The solvent in the solution is water, preferably deionized water.

5. The method according to any one of claims 1-3, wherein, The dispersant is polyvinyl alcohol and / or polyvinyl butyral, preferably polyvinyl butyral; Preferably, the thickener is glycerin and / or hydroxypropyl methylcellulose, more preferably hydroxypropyl methylcellulose; Preferably, the co-solvent is N-methylpyrrolidone and / or N,N-dimethylformamide, more preferably N,N-dimethylformamide; Preferably, the salt of the polyacrylic acid is sodium polyacrylate.

6. The method according to any one of claims 1-3, wherein, In step 1), the solution is coated onto the substrate using a dip-coating method.

7. The method according to any one of claims 1-3, wherein, The substrate is selected from ceramic film, titanium plate or niobium plate.

8. The method according to any one of claims 1-3, wherein, In step 1), the drying temperature is 5-45℃ and the drying time is 12-48h.

9. The method according to any one of claims 1-3, wherein, In step 2), the conditions for the first annealing include: an annealing temperature of 500-900℃ and an annealing time of 2-10h.

10. The method according to any one of claims 1-3, wherein, In step 3), the conditions for the second annealing include: an annealing temperature of 500-900℃ and an annealing time of 2-10h.

11. The Ti4O7 electrode prepared by the method according to any one of claims 1-10.

12. The application of the Ti4O7 electrode prepared by the method according to any one of claims 1-10 in the treatment of saline organic wastewater.

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