A non-metallic element doped titanium dioxide anode and its preparation method and application

Abstract

The present invention discloses a non-metallic element doped titanium oxide anode and its preparation method and application, belonging to the field of electrochemical technology. The present invention is used to solve the technical problems in the prior art that the catalytic activity of a single titanium oxide anode is low, the electrical insulation of the titanium oxide electrode is poor, and it is easy to corrode, resulting in a short service life of the electrode. A method for preparing a non-metallic element doped titanium oxide anode comprises the following steps: reaction system A is deposited onto the surface of a modified polytetrafluoroethylene film by vacuum filtration to obtain a first deposited film layer; reaction system B continues to be deposited onto the surface of the first deposited film layer by vacuum filtration to form a second deposited film layer, which is a composite anode; the composite anode is subjected to post-processing to prepare a non-metallic element doped titanium oxide anode. The titanium oxide anode prepared by the present invention has the advantages of high catalytic degradation activity, good mechanical properties, and good electrical insulation properties.

Description

Technical Field

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

[0002] As China's urbanization accelerates, the amount of wastewater generated is increasing day by day. Among the various wastewater treatment methods, electrochemical oxidation is a treatment method with many advantages, such as high efficiency, no secondary pollution, and low energy consumption. It has attracted widespread attention in the field of wastewater treatment. The key to electrochemical oxidation technology is to generate a large amount of strong oxidizing active substances through various means. It has the advantage of effectively degrading stable and complex wastewater.

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

[0004] Titanium dioxide, as an emerging electrocatalytic anode material, has a unique crystal structure and excellent performance. The lack of oxygen atoms in titanium dioxide leads to the formation of shear planes in the crystal structure, which gives titanium dioxide high conductivity and high stability. Organic pollutants are first adsorbed on the anode surface and undergo direct electron transfer through the anode surface; in this process, the molecular chains of organic pollutants are decomposed by oxidation. Among them, the direct oxidation rate mainly depends on the electrocatalytic activity of the anode material. Therefore, how to composite titanium dioxide anodes with other conductive polymers and dope them with non-metallic elements to improve their own catalytic activity is a hot research topic.

[0005] Patent application CN112064084A discloses a method for preparing a single-atom metal titanium oxide electrode. A metal salt is dissolved in deionized water to produce a metal precursor salt solution. This metal precursor salt solution is then deposited onto the surface of a titanium oxide electrode via electrochemical deposition to produce an electrocatalytic electrode material containing dispersed metal atoms. However, the titanium oxide anode itself has poor electrical insulation and is susceptible to corrosion, which shortens the service life of the resulting titanium oxide electrode.

[0006] In view of the technical defects in this aspect, a solution is now proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide a non-metallic element doped titanium dioxide anode and its preparation method and application, which are used to solve the technical problems in the prior art of low catalytic activity of a single titanium dioxide anode, poor electrical insulation of the titanium dioxide electrode, easy corrosion, and short service life of the electrode.

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

[0009] A method for preparing a non-metallic element-doped titanium oxide anode comprises the following steps:

[0010] Reaction system A is deposited onto the surface of a modified polytetrafluoroethylene film by vacuum filtration to obtain a first deposited film layer; reaction system B is further deposited onto the surface of the first deposited film layer by vacuum filtration to form a second deposited film layer, which is a composite anode; the composite anode is post-processed to obtain a non-metallic element-doped titanium dioxide anode;

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

[0012] The reaction system B is obtained by mixing titanium oxide powder and ethanol and performing ultrasonic dispersion.

[0013] The titanium dioxide anode prepared by the present invention has a multi-layer composite structure, with a modified polytetrafluoroethylene film as a base layer, reaction system A is deposited on the modified polytetrafluoroethylene film to form a first deposited film layer; reaction system B is deposited on the first deposited film layer to form a second deposited film layer, thereby preparing a titanium dioxide anode;

[0014] The method for preparing the modified polytetrafluoroethylene film comprises the following steps:

[0015] A1, toluene and water are mixed to obtain a solvent; methyldichlorosilane, dimethyldichlorosilane and trimethylchlorosilane are added to the solvent to obtain a mixed solution;

[0016] A2. The polytetrafluoroethylene emulsion and the mixed liquid are mixed, 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.

[0017] Using a mixture of toluene and water as the solvent, methyldichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane undergo a hydrolysis reaction to produce a mixed solution containing multiple silanol functional groups. This mixed solution can be used as a multifunctional coupling agent to modify polytetrafluoroethylene, thereby producing a modified polytetrafluoroethylene film.

[0018] Furthermore, in step A1, the amount ratio of toluene, water, methyldichlorosilane, dimethyldichlorosilane and trimethylchlorosilane is 80mL:100mL:40-50mL:30-40mL:10mL; in step A2, the mass ratio of polytetrafluoroethylene emulsion and mixed liquid is 2:7-10, the mixing speed is 100-200r / min, and the mixing time is 1-2h; the drying temperature is 70-80℃, and the drying time is 5-10min; the high-temperature calcination temperature is 355-380℃, and the high-temperature calcination time is 5-15min. The thickness of the modified polytetrafluoroethylene film formed is 70-90μm.

[0019] Furthermore, the method for preparing the carbon nanotubes doped with non-metallic elements comprises the following steps:

[0020] The acidified carbon nanotubes and thiourea are mixed and ground uniformly to obtain a mixed powder; the mixed powder is heated to 350-400° C. under a nitrogen atmosphere for 2-3 hours, and then cooled to room temperature to obtain a calcined mixed powder; the calcined mixed powder is successively washed with deionized water and vacuum-dried to prepare carbon nanotubes doped with non-metallic elements.

[0021] Furthermore, the preparation method of the acidified carbon nanotubes is: immersing multi-walled carbon nanotubes in a 5-10%wt dilute nitric acid solution, heating at 100-105°C for 2-3h, then filtering and collecting 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] Multi-walled carbon nanotubes are pre-treated with nitric acid to enrich the number of hydroxyl and carboxyl functional groups within the nanotubes, resulting in acidified carbon nanotubes. The acidified carbon nanotubes are then mixed with thiourea and calcined at high temperatures. These active sites occupied by the hydroxyl and carboxyl functional groups become defects, which are then replaced by sulfur and nitrogen, forming carbon nanotubes doped with non-metallic elements.

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

[0024] Furthermore, the method for preparing the titanium oxide powder comprises the following steps: placing rutile titanium oxide in a hydrogen atmosphere at 1000-1100° C. and performing high-temperature reduction for 20-24 hours to prepare the titanium oxide powder.

[0025] Furthermore, when preparing the first deposited film layer, the vacuum filtration pressure is 20-30 kPa; when preparing the second deposited film layer, the vacuum filtration pressure is 30-40 kPa; the post-processing steps of the composite anode include: the composite anode is cleaned 2-3 times with ultrapure water 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 minutes; the ultrasonic dispersion frequency of titanium oxide powder and ethanol is 20-30 KHz, and the ultrasonic duration is 10-20 minutes.

[0026] As another aspect of the present invention, a method for preparing a non-metallic element-doped titanium oxide anode is provided to prepare a non-metallic element-doped titanium oxide anode.

[0027] As another aspect of the present invention, a non-metallic element-doped titanium oxide anode is used for removing organic pollutants from water.

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

[0029] 1. The present invention utilizes a modified polytetrafluoroethylene film as a substrate, sequentially depositing a first and second deposited film layer using vacuum filtration to ultimately produce a composite anode, namely, a non-metallic element-doped titania anode. The first deposited film layer comprises carbon nanotubes doped with non-metallic elements, and the second deposited film layer comprises titania powder. The polytetrafluoroethylene film, as the substrate for the titania anode, provides insulation, chemical resistance, mechanical support, and improves the electrical insulation properties of the prepared titania anode. To further enhance the chemical adhesion between the deposited polytetrafluoroethylene film layer and the first and second deposited film layers, the present invention utilizes a mixed hydrolyzate of methyldichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane to modify the polytetrafluoroethylene film. Compared to conventional coupling agents, this mixture possesses multiple functionalities and forms more Si-O bonds with polytetrafluoroethylene, thereby enhancing the deposition density and fastness between the first and second deposited film layers and the polytetrafluoroethylene film. In addition, the reaction activity of the modified polytetrafluoroethylene film with carbon nanotubes doped with non-metallic elements and titanium oxide powder is enhanced, which can further improve its own catalytic activity.

[0030] 2. As a carbon-based material, carbon nanotubes have the advantages of large specific surface area, stable structure, and more pores. If non-metallic elements are doped into carbon nanotubes, the carbon nanotubes can play a role in wrapping the non-metallic elements, preventing excessive aggregation of non-metallic element particles, thereby retaining the strong catalytic properties of the non-metallic elements and prolonging the catalytic time. Among them, multi-walled carbon nanotubes are made of concentrically stacked multiple layers of graphene sheets, with relatively large tube diameters, thick tube walls, and high mechanical modulus. However, their specific surface area is relatively small. The present invention pre-acidifies the multi-walled carbon nanotubes with nitric acid to enrich the number of functional groups and active sites; then dopes them with thiourea, and through a high-temperature calcination process, allows nitrogen and sulfur elements to replace the active site positions, 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 non-metallic element-doped carbon nanotubes have higher catalytic activity.

[0031] 3. The present invention utilizes a vacuum filtration process to composite the modified polytetrafluoroethylene film, the first deposited film layer, and the second deposited film layer. The thickness of the resulting titania anode film is adjusted by adjusting the concentration of the non-metallic element-doped carbon nanotubes in reaction system A, the concentration of the titania powder in reaction system B, and the vacuum filtration pressure. The layers are tightly bonded together by chemical bonds, resulting in a non-metallic element-doped titania anode with excellent mechanical properties, high electrochemical activity, and efficient organic wastewater degradation. This simplified process for preparing the composite anode is suitable for continuous production, reducing production costs. DETAILED DESCRIPTION

[0032] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] The multi-walled carbon nanotubes used in Examples 1-3 of the present invention were purchased from Beijing Tanyang 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 the item number 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 Bangti Industrial Co., Ltd., with the item number 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 embodiment provides a method for preparing carbon nanotubes doped with non-metallic elements for a non-metallic element-doped titanium dioxide anode, comprising the following steps:

[0036] A1. Immerse multi-walled carbon nanotubes in a 5% wt dilute nitric acid solution (solid-to-liquid ratio of 1:5), heat to 100°C, maintain at a slight boil for 2 hours, and then filter and collect the solid. The solid is washed with deionized water and dried at 70°C to constant weight to obtain acidified carbon nanotubes.

[0037] A2. Weigh 2 g of acidified carbon nanotubes and 1 g of thiourea, mix them, and grind them evenly to obtain a mixed powder. The mixed powder is heated to 350°C at a rate of 10°C / min, calcined under a nitrogen atmosphere for 2 h, and then cooled to room temperature to obtain a calcined mixed powder. The calcined mixed powder is washed sequentially 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 embodiment provides a method for preparing carbon nanotubes doped with non-metallic elements for a non-metallic element-doped titanium dioxide anode, comprising the following steps:

[0040] A1. Immerse multi-walled carbon nanotubes in an 8% wt dilute nitric acid solution (solid-to-liquid mass ratio of 1:8), heat to 103°C, maintain at a slight boiling point for 2.5 hours, and then filter and collect the solids. The solids are washed with deionized water and dried at 75°C to constant weight to obtain acidified carbon nanotubes.

[0041] A2. Weigh 2.5 g of acidified carbon nanotubes and 1.5 g of thiourea, mix and grind to obtain a mixed powder. The mixed powder is heated to 380°C at a rate of 8°C / min, calcined under a nitrogen atmosphere for 2.2 h, and then cooled to room temperature to obtain a calcined mixed powder. The calcined mixed powder is washed sequentially 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 embodiment provides a method for preparing carbon nanotubes doped with non-metallic elements for a non-metallic element-doped titanium dioxide anode, comprising the following steps:

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

[0045] A2. Weigh 3 g of acidified carbon nanotubes and 2 g of thiourea, mix them, and grind them evenly to obtain a mixed powder. The mixed powder is heated to 400°C at a rate of 5°C / min, calcined under a nitrogen atmosphere for 3 h, and then cooled to room temperature to obtain a calcined mixed powder. The calcined mixed powder is washed sequentially 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 embodiment provides a method for preparing a modified polytetrafluoroethylene film for a non-metallic element-doped titanium oxide anode, comprising the following steps:

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

[0049] B2, polytetrafluoroethylene emulsion (polytetrafluoroethylene emulsion solid content: 60% wt), and the mixed solution were mixed in a mass ratio of 2:7, stirred at 100 rpm for 1 hour, and then dried in a 70°C forced air oven for 5 minutes to obtain a reactant. The reactant was transferred to a muffle furnace and sintered at 355°C for 5 minutes to produce a modified polytetrafluoroethylene film with a thickness of 70 μm.

[0050] Example 5

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

[0052] B1. Select a 500mL reactor, add 80mL of toluene and 100mL of water, and mix to obtain a solvent. The reactor is placed at room temperature and stirred at 150r / min. 45mL of methyldichlorosilane, 35mL of dimethyldichlorosilane, and 10mL of trimethylchlorosilane are added to the reactor in sequence to obtain a mixed solution.

[0053] B2, polytetrafluoroethylene emulsion (polytetrafluoroethylene emulsion solid content: 60% wt), and the mixed solution were mixed in a mass ratio of 2:8 and stirred at 150 rpm for 1.5 hours. The mixture was then dried in a 75°C forced air oven for 8 minutes to obtain a reactant. The reactant was transferred to a muffle furnace and sintered at 375°C for 10 minutes to produce 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-metallic element-doped titanium oxide anode, comprising the following steps:

[0056] B1. Select a 500mL reactor, add 80mL of toluene and 100mL of water, mix well, and obtain a solvent. The reactor is placed at room temperature, with a stirring speed of 200r / min, and 50mL of methyldichlorosilane, 40mL of dimethyldichlorosilane, and 10mL of trimethylchlorosilane are added to the reactor in sequence to obtain a mixed solution.

[0057] B2, polytetrafluoroethylene emulsion (polytetrafluoroethylene emulsion solid content: 60% by weight), and the mixed solution were mixed in a mass ratio of 2:10 and stirred at 200 rpm for 2 hours. The mixture was then dried in an 80°C forced air oven for 10 minutes to obtain a reactant. The reactant was transferred to a muffle furnace and sintered at 380°C for 15 minutes to produce a modified polytetrafluoroethylene film with a thickness of 90 μm.

[0058] Example 7

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

[0060] S1. Placing rutile titanium oxide in a hydrogen atmosphere at 1000° C. and subjecting it to high-temperature reduction for 24 hours to prepare titanium dioxide powder.

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

[0062] Example 8

[0063] This embodiment provides a method for preparing a non-metallic element-doped titanium dioxide anode, comprising the following steps:

[0064] S1. Placing rutile titanium oxide in a hydrogen atmosphere at 1060° C. and reducing it at high temperature for 22 hours to prepare titanium dioxide powder.

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

[0066] Example 9

[0067] This embodiment provides a method for preparing a non-metallic element-doped titanium dioxide anode, comprising the following steps:

[0068] S1. Placing rutile titanium oxide in a hydrogen atmosphere at 1100° C. and subjecting it to high-temperature reduction for 24 hours to prepare titanium dioxide powder.

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

[0070] Comparative Example 1

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

[0072] Comparative Example 2

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

[0074] Comparative Example 3

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

[0076] Performance test: A dual-chamber electrochemical chlorination device was prepared, wherein the anode material of the device was a 3 cm diameter non-metallic element doped titanium dioxide anode prepared in Examples 7-9 and Comparative Examples 1-3, and the cathode material was a carbon rod with a diameter of 6 mm and a height of 4 cm.

[0077] 1. The adsorption characteristics of the non-metallic element-doped titanium dioxide anodes prepared in Examples 7-9 and Comparative Examples 1-3 were examined using a static capacitance method, using nitrogen as the adsorption medium. The monolayer saturated adsorption capacity was calculated using the BET theoretical model and equivalently by measuring the equilibrium saturated adsorption capacity of nitrogen on the sample surface.

[0078] 2. The electrochemical activity of the titanium dioxide anodes prepared in Examples 7-9 and Comparative Examples 1-3 was tested using cyclic voltammetry, and the currents at voltages of 1 V and 2 V were recorded.

[0079] 3. The non-metallic element doped titanium oxide anode prepared in the above Examples 7-9 and Comparative Examples 1-3 was tested at 1.15 mA / cm 2 The applied current density was 1.5, the pH value at the anode was 3, the cathode used 0.5M sodium sulfate as the electrolyte, the influent methylene blue concentration was 50mg / L, and the degradation rate of methylene blue was recorded after 100 minutes of reaction. Specific test results are shown in the table below.

[0080] Table 1. Sample performance test data

[0081] Group Project 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: Table 1 shows that the non-metallic element-doped titanium dioxide anodes prepared in Examples 7-9 of the present invention utilize modified polytetrafluoroethylene as the base layer and reaction system A containing carbon nanotubes as the first deposited film layer, resulting in a high specific surface area. However, in Comparative Example 1, the multi-walled carbon nanotubes were not acidified with a dilute nitric acid solution during the preparation of the non-metallic element-doped carbon nanotubes. This acidification results in a higher specific surface area for the multi-walled carbon nanotubes, resulting in a lower specific surface area for the titanium dioxide anode prepared in Comparative Example 1.

[0083] The non-metallic element-doped titanium dioxide anodes prepared in Examples 7-9 of the present invention exhibited good electrochemical activity, as evidenced by the larger current values ​​at both 1V and 2V for the titanium dioxide anodes prepared in Comparative Examples 7-9. However, in Comparative Example 3, when preparing the non-metallic element-doped titanium dioxide anode, equal masses of Reaction System A and Reaction System B were mixed and then directly deposited on the surface of modified polytetrafluoroethylene; compared to the case where Reaction System B was deposited solely on the anode surface, its electrochemical activity was reduced.

[0084] The non-metallic element-doped titanium dioxide anodes prepared in Examples 7-9 of the present invention all have high degradation rates 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 instead of the multifunctional mixture, which reduced the degree of modification of the polytetrafluoroethylene film, weakened the reaction activity with the carbon nanotubes doped with non-metallic elements and titanium dioxide powder, and reduced the catalytic activity, thereby reducing the degradation rate of methylene blue during the same operating time.

[0085] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0086] Throughout this specification, references to terms such as "one embodiment," "example," and "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0087] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a non-metallic element doped titanium dioxide anode, characterized in that: The following steps are involved: The reaction system A is deposited onto the surface of the modified polytetrafluoroethylene film by vacuum filtration to obtain a first deposited film layer; The reaction system B is continuously deposited onto the surface of the first deposited film layer by vacuum filtration to form a second deposited film layer, which is a composite anode. The composite anode is then post-processed to obtain a non-metallic element-doped titanium oxide anode. The reaction system A is obtained by mixing carbon nanotubes doped with non-metallic elements and ethanol and performing ultrasonic dispersion; The reaction system B is prepared by mixing titanium oxide powder and ethanol and performing ultrasonic dispersion; The method for preparing the modified polytetrafluoroethylene film comprises the following steps: A1, toluene and water are mixed to obtain a solvent; methyldichlorosilane, dimethyldichlorosilane and trimethylchlorosilane are added to the solvent to obtain a mixed solution; A2. The polytetrafluoroethylene emulsion and the mixed liquid are mixed, 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.

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

3. The method for preparing a non-metallic element-doped titanium oxide anode according to claim 1, characterized in that: The method for preparing carbon nanotubes doped with non-metallic elements comprises the following steps: The acidified carbon nanotubes and thiourea are mixed and ground uniformly to obtain a mixed powder; the mixed powder is heated to 350-400° C. under a nitrogen atmosphere for 2-3 hours, and then cooled to room temperature to obtain a calcined mixed powder; the calcined mixed powder is successively washed with deionized water and vacuum-dried to prepare carbon nanotubes doped with non-metallic elements.

4. The method for preparing a non-metallic element-doped titanium oxide anode according to claim 3, characterized in that: The preparation method of the acidified carbon nanotubes comprises: immersing multi-walled carbon nanotubes in a 5-10%wt dilute nitric acid solution, heating at 100-105°C for 2-3h, filtering, collecting solids, and obtaining the acidified carbon nanotubes; the solid-liquid mass ratio of the multi-walled carbon nanotubes to the dilute nitric acid is 1:5-10.

5. The method for preparing a non-metallic element-doped titanium oxide anode according to claim 3, 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.

6. The method for preparing a non-metallic element-doped titanium oxide anode according to claim 1, characterized in that: The method for preparing titanium oxide powder comprises the following steps: placing rutile titanium oxide in a hydrogen atmosphere at 1000-1100° C. and performing high-temperature reduction for 20-24 hours to prepare titanium oxide powder.

7. The method for preparing a non-metallic element-doped titanium oxide anode according to claim 1, characterized in that: When preparing the first deposited film layer, the vacuum filtration pressure is 20-30 kPa; when preparing the second deposited film layer, the vacuum filtration pressure is 30-40 kPa; the post-processing steps of the composite anode include: the composite anode is cleaned 2-3 times with ultrapure water to clean 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 minutes; the ultrasonic dispersion frequency of titanium oxide powder and ethanol is 20-30 kHz, and the ultrasonic duration is 10-20 minutes.

8. A titanium oxide anode doped with non-metallic elements, characterized in that: The non-metallic element-doped titanium oxide anode is prepared by the method for preparing the non-metallic element-doped titanium oxide anode according to any one of claims 1 to 7.

9. Use of the non-metallic element-doped titanium dioxide anode as claimed in claim 8 in removing organic pollutants from water.