Non-metallic element doped titanium black anode and preparation method and application thereof

Abstract

The invention discloses a non-metallic element doped titanium black anode and a preparation method and application thereof, and belongs to the technical field of electrochemistry. The method is used for solving the technical problems that in the prior art, a single titanium black anode is low in catalytic activity, and a titanium black electrode is poor in electrical insulativity and prone to corrosion, so that the service life of the electrode is short. A preparation method of a non-metallic element doped titanium black anode comprises the following steps that a reaction system A is deposited on the surface of a modified polytetrafluoroethylene film in a vacuum filtration mode, and a first deposition film layer is obtained; the reaction system B is continuously deposited on the surface of the first deposition film layer in a vacuum filtration manner to form a second deposition film layer, namely the composite anode; and carrying out post-process treatment on the composite anode to prepare the non-metallic element doped titanium black anode. The titanium black anode prepared by the invention has the advantages of high catalytic degradation activity, good mechanical property and good electrical insulation property.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical technology, and particularly to a titanium suboxide anode doped with non-metallic elements, a preparation method thereof, and an application thereof. Background Art

[0002] With the acceleration of China's urbanization process, the generation of wastewater is increasing day by day; among many wastewater treatments, the electrochemical oxidation method is a treatment method with many advantages such as high efficiency, no secondary pollution, and low energy consumption, and has received extensive attention in the field of wastewater treatment. The key to the electrochemical oxidation technology is to generate a large amount of strongly oxidizing active substances in various ways, which has the advantage of effectively degrading wastewater with stable properties and complex components;

[0003] Among them, in the application field of degrading organic wastewater, titanium suboxide has the advantages of high conductivity, high electrochemical stability, and excellent corrosion resistance.

[0004] As a new type of electrocatalytic anode material, titanium suboxide has a unique crystal structure and excellent properties. The absence of oxygen atoms in titanium suboxide leads to the formation of a shear plane in the crystal structure, endowing titanium suboxide with high conductivity and high stability. Organic pollutants are first adsorbed on the anode surface and directly transfer electrons through the anode surface; in this process, the molecular chain of organic pollutants is decomposed by oxidation. Among them, the direct oxidation rate mainly depends on the electrocatalytic activity of the anode material. Therefore, how to composite the titanium suboxide anode with other conductive polymers and dope non-metallic elements to improve its own catalytic activity has become a research hotspot.

[0005] Patent application CN112064084A discloses a preparation method of a metal single-atom titanium suboxide electrode. A metal salt is dissolved in deionized water to obtain a metal precursor salt solution. The obtained metal precursor salt solution is deposited on the surface of the titanium suboxide electrode by electrochemical deposition to prepare an electrocatalytic electrode material with metal single atoms dispersed. However, the titanium suboxide anode itself has poor electrical insulation and is easily corroded, thus shortening the service life of the prepared titanium suboxide electrode.

[0006] A solution is proposed for the technical defects in this regard. Summary of the Invention

[0007] The purpose of the present invention is to provide a titanium suboxide anode doped with non-metallic elements, a preparation method thereof, and an application thereof, which are used to solve the technical problems in the prior art that the catalytic activity of a single titanium suboxide anode is low, the electrical insulation of the titanium suboxide electrode is poor, it is easily corroded, and the service life of the electrode is short.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] A preparation method of a sub-oxidized titanium anode doped with a non-metallic element, comprising the following steps:

[0010] The reaction system A is deposited on the surface of the modified polytetrafluoroethylene film by vacuum filtration to obtain a first deposited film layer; the reaction system B is continuously deposited on the surface of the first deposited film layer by vacuum filtration to form a second deposited film layer, which is the composite anode; the composite anode is subjected to post-process treatment to prepare a sub-oxidized titanium anode doped with a non-metallic element.

[0011] The reaction system A is obtained by mixing and ultrasonic dispersing carbon nanotubes doped with non-metallic elements and ethanol.

[0012] The reaction system B is obtained by mixing and ultrasonic dispersing titanium suboxide powder and ethanol.

[0013] The sub-oxidized titanium anode prepared by the present invention has a multi-layer composite structure. The modified polytetrafluoroethylene film is used as the base layer, and the reaction system A is deposited on the modified polytetrafluoroethylene film to form a first deposited film layer; the reaction system B is deposited on the first deposited film layer to form a second deposited film layer, and then the sub-oxidized titanium anode is prepared.

[0014] Further, the preparation method of the modified polytetrafluoroethylene film comprises the following steps:

[0015] A1. Mix toluene and water to obtain a solvent; add methyl dichlorosilane, dimethyldichlorosilane and trimethylchlorosilane to the solvent to obtain a mixed solution.

[0016] A2. Mix and stir the polytetrafluoroethylene emulsion and the mixed solution, and dry to obtain a reactant; transfer the reactant to a muffle furnace for high-temperature calcination to prepare a modified polytetrafluoroethylene film.

[0017] Using a mixture of toluene and water as the solvent, methyl dichlorosilane, dimethyldichlorosilane and trimethylchlorosilane undergo hydrolysis reactions to generate a mixed solution containing polysilol functional groups. The mixed solution can be used as a multi-functional coupling agent to modify polytetrafluoroethylene, thereby preparing a modified polytetrafluoroethylene film.

[0018] Further, in step A1, the dosage ratio of toluene, water, methyl dichlorosilane, dimethyldichlorosilane and trimethylchlorosilane is 80 mL: 100 mL: 40 - 50 mL: 30 - 40 mL: 10 mL; in step A2, the mass ratio of the polytetrafluoroethylene emulsion to the mixed solution is 2: 7 - 10, the rotation speed of the mixing and stirring is 100 - 200 r / min, and the duration of the mixing and stirring is 1 - 2 h; the drying temperature is 70 - 80 °C, and the drying duration is 5 - 10 min; the high-temperature calcination temperature is 355 - 380 °C, and the high-temperature calcination duration is 5 - 15 min, and the thickness of the formed modified polytetrafluoroethylene film is 70 - 90 μm.

[0019] Further, the preparation method of the carbon nanotubes doped with non-metallic elements comprises the following steps:

[0020] Mix and grind the acidified carbon nanotubes and thiourea evenly to obtain a mixed powder; heat the mixed powder to 350 - 400 °C and keep it for 2 - 3 h in a nitrogen atmosphere, then cool it to room temperature to obtain the calcined mixed powder; wash the calcined mixed powder with deionized water and then dry it in vacuum to prepare the carbon nanotubes doped with non-metallic elements.

[0021] Further, the preparation method of the acidified carbon nanotubes is as follows: immerse multi-walled carbon nanotubes in a 5 - 10%wt dilute nitric acid solution, heat at 100 - 105 °C for 2 - 3 h, then filter and collect the solid to obtain the acidified carbon nanotubes; the solid-liquid mass ratio of the multi-walled carbon nanotubes to the dilute nitric acid is 1:5 - 10.

[0022] The multi-walled carbon nanotubes are pre-acidified with nitric acid to enrich the number of internal doped hydroxyl and carboxyl functional groups, obtaining acidified carbon nanotubes. The acidified carbon nanotubes are mixed with thiourea and calcined at high temperature. The active sites occupied by the hydroxyl and carboxyl functional groups will form defects and then be replaced by sulfur and nitrogen elements to form the carbon nanotubes doped with non-metallic elements.

[0023] Further, the dosage ratio of the acidified carbon nanotubes to thiourea is 2 - 3 g:1 - 2 g, and the heating rate is 5 - 10 °C / min.

[0024] Further, the preparation method of the titanium suboxide powder comprises the following steps: place rutile titanium oxide in a hydrogen atmosphere at 1000 - 1100 °C and reduce it at high temperature for 20 - 24 h to prepare the titanium suboxide powder.

[0025] Further, when preparing the first deposition film layer, the pressure of vacuum filtration is 20 - 30 kPa; when preparing the second deposition film layer, the pressure of vacuum filtration is 30 - 40 kPa; the post-process treatment steps of the composite anode include: washing the composite anode with ultrapure water 2 - 3 times to remove surface impurities; the ultrasonic dispersion frequency of the carbon nanotubes doped with non-metallic elements and the ethanol solvent is 20 - 30 KHz, and the ultrasonic duration is 10 - 20 min; the ultrasonic dispersion frequency of the titanium suboxide powder and ethanol is 20 - 30 KHz, and the ultrasonic duration is 10 - 20 min.

[0026] As another aspect of the present invention, a titanium suboxide anode doped with non-metallic elements prepared by the preparation method of a titanium suboxide anode doped with non-metallic elements.

[0027] As another aspect of the present invention, an application of a titanium suboxide anode doped with non-metallic elements in removing organic pollutants in water.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention uses a modified polytetrafluoroethylene film as the base layer, and sequentially deposits a first deposition film layer and a second deposition film layer by vacuum filtration to finally obtain a composite anode, that is, a titanium suboxide anode doped with non-metallic elements; wherein, the first deposition film layer is carbon nanotubes doped with non-metallic elements, and the second deposition film layer is titanium suboxide powder. The polytetrafluoroethylene film serves as the substrate of the titanium suboxide anode, playing roles of insulation, chemical corrosion resistance, mechanical support, and improving the electrical insulation of the prepared titanium suboxide anode. In order to further improve the chemical adhesion performance between the polytetrafluoroethylene film deposition layer and the first deposition film layer and the second deposition film layer, the present invention uses a mixed hydrolysis solution of methyl dichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane to modify the polytetrafluoroethylene film. Compared with conventional coupling agents, the mixture has multiple functionalities and forms a richer Si-O bond with polytetrafluoroethylene, thereby enhancing the deposition density and deposition fastness between the first deposition film layer, the second deposition film layer, and the polytetrafluoroethylene film. In addition, the reaction activity between the modified polytetrafluoroethylene film and the carbon nanotubes doped with non-metallic elements and titanium suboxide powder is enhanced, which can further improve its own catalytic activity.

[0030] 2. As a carbon-based material, carbon nanotubes have the advantages of a large specific surface area, stable structure, and many pores; if non-metallic elements are doped into carbon nanotubes, the carbon nanotubes can play a role in encapsulating the non-metallic elements, preventing excessive aggregation of non-metallic element particles, thereby retaining the strong catalytic property of the non-metallic elements and prolonging the catalytic time. Among them, multi-walled carbon nanotubes are composed of multiple layers of graphene sheets concentrically nested, with a relatively large diameter and a thick tube wall, and have a relatively high mechanical modulus. However, its specific surface area is relatively small; the present invention pre-acidifies multi-walled carbon nanotubes with nitric acid to enrich the number of functional groups and active sites; then sulfur urea is doped, and through a high-temperature calcination process, nitrogen and sulfur elements replace the positions of the active sites, thereby increasing the proportion of doped non-metallic elements, and preparing carbon nanotubes with good mechanical properties and a high proportion of doped non-metallic elements. The above-mentioned carbon nanotubes doped with non-metallic elements have higher catalytic activity.

[0031] 3. The present invention uses a vacuum filtration process to compound the modified polytetrafluoroethylene film, the first deposition film layer, and the second deposition film layer. By adjusting the concentration of carbon nanotubes doped with non-metallic elements in reaction system A, the concentration of titanium suboxide powder in reaction system B, and the pressure of vacuum filtration, the thickness of the prepared titanium suboxide anode film is adjusted. The layers are tightly bonded by chemical bonds, and a titanium suboxide anode doped with non-metallic elements with good mechanical properties, high electrochemical activity, and high efficiency in degrading organic wastewater is prepared. The above process for preparing the composite anode is simplified, suitable for continuous process production, and reduces production costs. Detailed implementation manners

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] The multi-walled carbon nanotubes used in Examples 1-3 of the present invention were purchased from Beijing Carbon Yang Technology Co., Ltd., with a fineness of 10-15 nm and a model of 100T; the polytetrafluoroethylene emulsion used in Examples 4-6 of the present invention was purchased from Suzhou Dianhui Plastic Raw Materials Co., Ltd., with a product number of DISP30, and the solid content of the polytetrafluoroethylene emulsion was 60%wt; the rutile titanium oxide used in Examples 7-9 of the present invention was purchased from Shenzhen Bangtai Industry Co., Ltd., with a product number of r-248; the silane coupling agent KH-550 used in Comparative Example 2 of the present invention was purchased from Nanjing Jingtianwei Chemical Co., Ltd.

[0034] Example 1

[0035] This example provides a method for preparing carbon nanotubes doped with non-metallic elements for a non-metallic element-doped titanium suboxide anode, including the following steps:

[0036] A1. The multi-walled carbon nanotubes are immersed in a 5%wt dilute nitric acid solution (solid-liquid mass ratio of 1:5), heated to 100 °C, and maintained at this slightly boiling state for 2 h, then filtered, and the solid is collected. The solid is washed with deionized water and then dried to a constant weight at 70 °C to obtain acidified carbon nanotubes.

[0037] A2. Weigh 2 g of acidified carbon nanotubes and 1 g of thiourea, mix and grind them evenly to obtain a mixed powder. The mixed powder is heated to 350 °C at a rate of 10 °C / min and calcined at high temperature in a nitrogen atmosphere for 2 h, and then cooled to room temperature to obtain the calcined mixed powder; the calcined mixed powder is washed successively with deionized water and ethanol and vacuum dried at 70 °C for 20 min to prepare carbon nanotubes doped with non-metallic elements.

[0038] Example 2

[0039] This example provides a method for preparing carbon nanotubes doped with non-metallic elements for a non-metallic element-doped titanium suboxide anode, including the following steps:

[0040] A1. The multi-walled carbon nanotubes are immersed in an 8%wt dilute nitric acid solution (solid-liquid mass ratio of 1:8), heated to 103 °C, and maintained at this slightly boiling state for 2.5 h, then filtered, and the solid is collected. The solid is washed with deionized water and then dried to a constant weight at 75 °C to obtain acidified carbon nanotubes.

[0041] A2. Weigh 2.5 g of acidified carbon nanotubes and 1.5 g of thiourea, mix them evenly by grinding to obtain a mixed powder. The mixed powder is heated to 380 °C at a rate of 8 °C / min, calcined at high temperature for 2.2 h in a nitrogen atmosphere, and then cooled to room temperature to obtain the calcined mixed powder; the calcined mixed powder is washed successively with deionized water and ethanol, and vacuum dried at 72 °C for 25 min to prepare carbon nanotubes doped with non-metallic elements.

[0042] Example 3

[0043] This example provides a method for preparing carbon nanotubes doped with non-metallic elements for a titanium suboxide anode doped with non-metallic elements, including the following steps:

[0044] A1. Immerse multi-walled carbon nanotubes in a 10%wt dilute nitric acid solution (the solid-liquid mass ratio is 1:10), heat to 105 °C, maintain at this slightly boiling state for 3 h, then filter and collect the solid. The solid is washed with deionized water and then dried to constant weight at 80 °C to obtain acidified carbon nanotubes.

[0045] A2. Weigh 3 g of acidified carbon nanotubes and 2 g of thiourea, mix them evenly by grinding to obtain a mixed powder. The mixed powder is heated to 400 °C at a rate of 5 °C / min, calcined at high temperature for 3 h in a nitrogen atmosphere, and then cooled to room temperature to obtain the calcined mixed powder; the calcined mixed powder is washed successively with deionized water and ethanol, and vacuum dried at 75 °C for 30 min to prepare carbon nanotubes doped with non-metallic elements.

[0046] Example 4

[0047] This example provides a method for preparing a modified polytetrafluoroethylene film for a titanium suboxide anode doped with non-metallic elements, including the following steps:

[0048] B1. Select a 500 mL reaction kettle, add 80 mL of toluene and 100 mL of water, mix evenly to obtain a solvent. The reaction kettle is placed at room temperature, and with a stirring speed of 100 r / min, 40 mL of methyl dichlorosilane, 30 mL of dimethyldichlorosilane and 10 mL of trimethylchlorosilane are added to the reaction kettle in sequence to obtain a mixed solution.

[0049] B2. Mix a polytetrafluoroethylene emulsion (the solid content of the polytetrafluoroethylene emulsion is 60%wt) and the mixed solution in a mass ratio of 2:7, mix and stir at 100 r / min for 1 h, and then dry in a blast drying oven at 70 °C for 5 min to obtain a reactant. The reactant is transferred to a muffle furnace and sintered at high temperature at 355 °C for 5 min to prepare a modified polytetrafluoroethylene film, and the thickness of the prepared modified polytetrafluoroethylene film is 70 μm.

[0050] Example 5

[0051] This embodiment provides a method for preparing a modified polytetrafluoroethylene film for a non-metal element doped titanium suboxide anode, comprising the following steps:

[0052] B1. Select a 500 mL reaction kettle, add 80 mL of toluene and 100 mL of water, mix well to obtain a solvent. Place the reaction kettle at room temperature, and with a stirring speed of 150 r / min, sequentially add 45 mL of methyl dichlorosilane, 35 mL of dimethyldichlorosilane, and 10 mL of trimethylchlorosilane into the reaction kettle to obtain a mixed solution.

[0053] B2. Mix the polytetrafluoroethylene emulsion (the solid content of the polytetrafluoroethylene emulsion is 60% wt) and the mixed solution in a mass ratio of 2:8, mix and stir at 150 r / min for 1.5 h, then dry in a blast drying oven at 75 °C for 8 min to obtain a reactant. Transfer the reactant to a muffle furnace and sinter at 375 °C for 10 min to prepare a modified polytetrafluoroethylene film with a thickness of 80 μm.

[0054] Example 6

[0055] This embodiment provides a method for preparing a modified polytetrafluoroethylene film for a non-metal element doped titanium suboxide anode, comprising the following steps:

[0056] B1. Select a 500 mL reaction kettle, add 80 mL of toluene and 100 mL of water, mix well to obtain a solvent. Place the reaction kettle at room temperature, and with a stirring speed of 200 r / min, sequentially add 50 mL of methyl dichlorosilane, 40 mL of dimethyldichlorosilane, and 10 mL of trimethylchlorosilane into the reaction kettle to obtain a mixed solution.

[0057] B2. Mix the polytetrafluoroethylene emulsion (the solid content of the polytetrafluoroethylene emulsion is 60% wt) and the mixed solution in a mass ratio of 2:10, mix and stir at 200 r / min for 2 h, then dry in a blast drying oven at 80 °C for 10 min to obtain a reactant. Transfer the reactant to a muffle furnace and sinter at 380 °C for 15 min to prepare a modified polytetrafluoroethylene film with a thickness of 90 μm.

[0058] Example 7

[0059] This embodiment provides a method for preparing a non-metal element doped titanium suboxide anode, comprising the following steps:

[0060] S1. Place rutile titanium oxide in a hydrogen atmosphere at 1000 °C and perform high-temperature reduction for 24 h to prepare titanium suboxide powder.

[0061] S2. Mix 10 mg of the carbon nanotubes doped with non-metallic elements prepared in Example 1 and ethanol solvent to obtain a 0.1%wt mixture A; ultrasonically disperse mixture A in an ultrasonic cell disruptor with an ultrasonic frequency of 20 KHz and an ultrasonic duration of 10 min to obtain a uniform reaction system A. Deposit reaction system A onto the surface of the modified polytetrafluoroethylene film prepared in Example 4 by vacuum filtration at a vacuum filtration pressure of 20 KPa to obtain a first deposited film layer. Mix 20 mg of titanium suboxide powder and ethanol solvent to obtain a 0.1%wt mixture B; ultrasonically disperse mixture B in an ultrasonic cell disruptor with an ultrasonic frequency of 20 KHz and an ultrasonic duration of 12 min to obtain a uniform reaction system B. Deposit reaction system B onto the surface of the first deposited film layer by vacuum filtration at a vacuum filtration pressure of 30 kPa to form a second deposited film layer, which is the composite anode. Wash the composite anode twice with ultrapure water to remove surface impurities and prepare a non-metallic element-doped titanium suboxide anode.

[0062] Example 8

[0063] This example provides a method for preparing a non-metallic element-doped titanium suboxide anode, including the following steps:

[0064] S1. Place rutile titanium oxide in a hydrogen atmosphere at 1060 °C and perform high-temperature reduction for 22 h to prepare titanium suboxide powder.

[0065] S2. Mix 16 mg of the carbon nanotubes doped with non-metallic elements prepared in Example 2 and ethanol solvent to obtain a 0.15%wt mixture A; ultrasonically disperse mixture A in an ultrasonic cell disruptor with an ultrasonic frequency of 25 KHz and an ultrasonic duration of 15 min to obtain a uniform reaction system A. Deposit reaction system A onto the surface of the modified polytetrafluoroethylene film prepared in Example 5 by vacuum filtration at a vacuum filtration pressure of 25 KPa to obtain a first deposited film layer. Mix 30 mg of titanium suboxide powder and ethanol solvent to obtain a 0.15%wt mixture B; ultrasonically disperse mixture B in an ultrasonic cell disruptor with an ultrasonic frequency of 25 KHz and an ultrasonic duration of 15 min to obtain a uniform reaction system B. Deposit reaction system B onto the surface of the first deposited film layer by vacuum filtration at a vacuum filtration pressure of 35 kPa to form a second deposited film layer, which is the composite anode. Wash the composite anode three times with ultrapure water to remove surface impurities and prepare a non-metallic element-doped titanium suboxide anode.

[0066] Example 9

[0067] This example provides a method for preparing a non-metallic element-doped titanium suboxide anode, including the following steps:

[0068] S1. Place rutile titanium oxide under a hydrogen atmosphere at 1100 °C and perform high-temperature reduction for 24 h to prepare titanium suboxide powder.

[0069] S2. Mix 20 mg of the carbon nanotubes doped with non-metallic elements prepared in Example 3 and ethanol solvent to obtain a 0.2%wt mixture A; disperse mixture A in an ultrasonic cell disruptor with an ultrasonic frequency of 30 KHz and an ultrasonic duration of 20 min to obtain a homogeneous reaction system A. The reaction system A is deposited on the surface of the modified polytetrafluoroethylene film prepared in Example 6 by vacuum filtration at a vacuum filtration pressure of 30 kPa to obtain a first deposited film layer. Mix 40 mg of titanium suboxide powder and ethanol solvent to obtain a 0.2%wt mixture B; disperse mixture B in an ultrasonic cell disruptor with an ultrasonic frequency of 30 KHz and an ultrasonic duration of 20 min to obtain a homogeneous reaction system B. The reaction system B is deposited on the surface of the first deposited film layer by vacuum filtration at a vacuum filtration pressure of 40 kPa to form a second deposited film layer, which is the composite anode. Wash the composite anode 3 times with ultrapure water to remove surface impurities to prepare a non-metallic element-doped titanium suboxide anode.

[0070] Comparative Example 1

[0071] Compared with Example 9 of the present invention, when preparing carbon nanotubes doped with non-metallic elements, multi-walled carbon nanotubes were not acidified with dilute nitric acid solution, but directly mixed with thiourea and calcined at high temperature to prepare carbon nanotubes doped with non-metallic elements.

[0072] Comparative Example 2

[0073] Compared with Example 9 of this comparative example, when preparing the modified polytetrafluoroethylene film, in the solvent obtained by mixing toluene and water, an equal volume of silane coupling agent KH-550 was added to replace methyl dichlorosilane, dimethyldichlorosilane and trimethylchlorosilane to prepare a mixed solution.

[0074] Comparative Example 3

[0075] Compared with Example 9 of this comparative example, when preparing a non-metallic element-doped titanium suboxide anode, the same mass of reaction system A and reaction system B were mixed evenly and then directly deposited on the surface of modified polytetrafluoroethylene to prepare a non-metallic element-doped titanium suboxide anode.

[0076] Performance test: Prepare a two-chamber electrochemical chlorination device. Among them, the anode material of the device is a non-metallic element-doped titanium suboxide anode with a diameter of 3 cm prepared in Examples 7-9 and Comparative Examples 1-3, and the cathode material is a carbon rod with a diameter of 6 mm and a height of 4 cm.

[0077] 1. The adsorption characteristics of the sub-oxidetitanium anodes doped with non-metallic elements prepared in Examples 7-9 and Comparative Examples 1-3 were detected by the static volumetric method, using nitrogen as the adsorption medium. The monolayer saturation adsorption capacity was equivalently obtained by using the BET theoretical model and measuring the equilibrium saturation adsorption amount of nitrogen on the sample surface.

[0078] 2. The electrochemical activities of the sub-oxidetitanium anodes prepared in Examples 7-9 and Comparative Examples 1-3 were detected by cyclic voltammetry. The currents at voltages of 1 V and 2 V were recorded respectively.

[0079] 3. An external current density of 1.15 mA / cm 2 was applied to the sub-oxidetitanium anodes doped with non-metallic elements prepared in the above Examples 7-9 and Comparative Examples 1-3. The pH value of the anode was 3. The cathode used 0.5 M sodium sulfate as the electrolyte, and the concentration of the influent methylene blue was 50 mg / L. After reacting for 100 min, the degradation rate of methylene blue was recorded. The specific test results are shown in the following table.

[0080] Table 1. Test data of sample performance

[0081] Group Item Example 7 Example 8 Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[Specific surface area / (m 2 / g)]]> 13.1 13.5 13.8 8.9 11.2 12.5 Current at 1V / (A) 0.06 0.07 0.08 0.05 0.04 0.02 Current at 2V / (A) 0.08 0.09 0.09 0.06 0.05 0.04 Methylene Blue Degradation Rate / (%) 99.2 99.5 99.7 90.2 89.1 80.1

[0082] Data analysis: According to the data in Table 1, it can be seen that the sub-oxidetitanium anodes doped with non-metallic elements prepared in Examples 7-9 of the present invention use modified polytetrafluoroethylene as the base layer and reaction system A containing carbon nanotubes as the first deposition film layer, so that the prepared sub-oxidetitanium anodes have a rich specific surface area. However, in Comparative Example 1, when preparing carbon nanotubes doped with non-metallic elements, the multi-walled carbon nanotubes were not acidified with dilute nitric acid solution; the specific surface area of the acidified multi-walled carbon nanotubes is larger, so the specific surface area value of the sub-oxidetitanium anode prepared in Comparative Example 1 decreases.

[0083] The sub-oxidetitanium anodes doped with non-metallic elements prepared in Examples 7-9 of the present invention have good electrochemical activities, which are manifested as larger current values of the sub-oxidetitanium anodes prepared in Examples 7-9 at 1 V and 2 V. However, in Comparative Example 3, when preparing the sub-oxidetitanium anodes doped with non-metallic elements, the same mass of reaction system A and reaction system B were mixed evenly and then directly deposited on the surface of the modified polytetrafluoroethylene; compared with the single deposition of reaction system B on the anode surface layer, its electrochemical activity decreases.

[0084] The titanium suboxide anodes doped with non-metallic elements prepared in Examples 7-9 of the present invention all have a high degradation rate for typical pollutants in industrial wastewater; however, in Comparative Example 2, when preparing the modified polytetrafluoroethylene film, the silane coupling agent KH-550 was used to replace the multi-functional mixture, resulting in a reduced degree of modification of the polytetrafluoroethylene film, weakened reactivity with carbon nanotubes doped with non-metallic elements and titanium suboxide powder, and reduced catalytic activity. Therefore, during the same operation time, the degradation rate of methylene blue decreased.

[0085] The above content is only an example and illustration of the structure of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claims, they should fall within the protection scope of the present invention.

[0086] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0087] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not elaborate all the details, nor do they limit the invention to the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, so that those skilled in the art of the present technology can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A preparation method of a sub-oxidized titanium anode doped with a non-metallic element, characterized in that, It includes the following steps: The reaction system A is deposited on the surface of the modified polytetrafluoroethylene film by vacuum filtration to obtain the first deposited film layer; The reaction system B is continuously deposited on the surface of the first deposited film layer by vacuum filtration to form the second deposited film layer, which is the composite anode; the composite anode is subjected to a post-process treatment to prepare a sub-oxidetitanium anode doped with non-metallic elements; The reaction system A is obtained by mixing carbon nanotubes doped with non-metallic elements and ethanol and ultrasonic dispersion; The reaction system B is obtained by mixing titanium suboxide powder and ethanol and ultrasonic dispersion.

2. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 1, characterized in that, The preparation method of the modified polytetrafluoroethylene film includes the following steps: A1. Toluene and water are mixed evenly to obtain a solvent; methyl dichlorosilane, dimethyldichlorosilane and trimethylchlorosilane are added to the solvent to obtain a mixed solution; A2. The polytetrafluoroethylene emulsion and the mixed solution are mixed and stirred, and dried to obtain a reactant; the reactant is transferred to a muffle furnace for high-temperature calcination to prepare a modified polytetrafluoroethylene film.

3. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 2, characterized in that, In step A1, the dosage ratio of toluene, water, methyl dichlorosilane, dimethyldichlorosilane and trimethylchlorosilane is 80 mL: 100 mL: 40 - 50 mL: 30 - 40 mL: 10 mL; in step A2, the mass ratio of the polytetrafluoroethylene emulsion and the mixed solution is 2: 7 - 10, the rotation speed of the mixing and stirring is 100 - 200 r / min, and the mixing and stirring time is 1 - 2 h; the drying temperature is 70 - 80 °C, and the drying time is 5 - 10 min; the high-temperature calcination temperature is 355 - 380 °C, and the high-temperature calcination time is 5 - 15 min, and the thickness of the formed modified polytetrafluoroethylene film is 70 - 90 μm.

4. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 1, characterized in that, The preparation method of the carbon nanotubes doped with non-metallic elements includes the following steps: The acidified carbon nanotubes and thiourea are mixed and ground evenly to obtain a mixed powder; the mixed powder is heated to 350 - 400 °C for 2 - 3 h in a nitrogen atmosphere, and then cooled to room temperature to obtain the calcined mixed powder; the calcined mixed powder is washed with deionized water and vacuum dried in sequence to prepare the carbon nanotubes doped with non-metallic elements.

5. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 4, characterized in that, The preparation method of the acidified carbon nanotubes is as follows: multi-walled carbon nanotubes are immersed in a 5 - 10%wt dilute nitric acid solution, heated at 100 - 105 °C for 2 - 3 h, and then filtered to collect the solid to obtain the acidified carbon nanotubes; the solid-liquid mass ratio of the multi-walled carbon nanotubes and the dilute nitric acid is 1: 5 - 10.

6. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 4, characterized in that, The dosage ratio of the acidified carbon nanotubes and thiourea is 2 - 3 g: 1 - 2 g, and the heating rate is 5 - 10 °C / min.

7. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 1, characterized in that, The preparation method of the titanium suboxide powder includes the following steps: rutile titanium oxide is placed in a hydrogen atmosphere at 1000 - 1100 °C and subjected to high-temperature reduction for 20 - 24 h to prepare the titanium suboxide powder.

8. The preparation method of a titanium suboxide anode doped with a non-metallic element according to claim 1, characterized in that, When preparing the first deposition film layer, the pressure of vacuum filtration is 20 - 30 kPa; when preparing the second deposition film layer, the pressure of vacuum filtration is 30 - 40 kPa; the post-process treatment steps of the composite anode include: the composite anode is washed 2 - 3 times with ultrapure water to wash surface impurities; the ultrasonic dispersion frequency of carbon nanotubes doped with non-metallic elements and ethanol solvent is 20 - 30 KHz, and the ultrasonic duration is 10 - 20 min; the ultrasonic dispersion frequency of titanium suboxide powder and ethanol is 20 - 30 KHz, and the ultrasonic duration is 10 - 20 min.

9. A titanium suboxide anode doped with a non-metallic element, characterized in that, The titanium suboxide anode doped with non-metallic elements is prepared by using the preparation method of the titanium suboxide anode doped with non-metallic elements according to any one of claims 1 - 8.

10. Application of the titanium suboxide anode doped with non-metallic elements according to claim 9 in removing organic pollutants in water.