Preparation method and application of defect-rich carbon nanotube bismuth-based composite photocatalytic material

Abstract

The invention provides a preparation method and application of a defect-rich carbon nanotube bismuth-based composite photocatalytic material, and belongs to the technical field of photocatalytic materials. The carbon nanotube bismuth-based composite photocatalytic material provided by the invention comprises bismuth oxyhalide and a modified carbon nanotube loaded on the bismuth oxyhalide, the modified carbon nano tube is a multi-wall carbon nano tube which is etched by adopting plasma. By utilizing the interface coupling effect of the multi-walled carbon nanotubes, the absorption spectrum of bismuth oxyhalide is expanded, and the recombination of current carriers is inhibited, so that the photocatalytic performance is improved; plasma etching is adopted to generate structural defects on the surface of the multi-walled carbon nanotube, the adsorption efficiency of active sites is increased, and the electron transfer performance of the carbon nanotube bismuth-based composite photocatalytic material is enhanced, so that the photocatalytic performance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalytic materials, and particularly relates to a preparation method and application of a defective carbon nanotube bismuth-based composite photocatalytic material. Background Art

[0002] Heterogeneous photocatalytic oxidation technology is a new and advanced technology that can directly utilize sunlight for clean production and environmental remediation. In recent years, relying on the characteristics of rich functional groups, strong electron transport ability, good light transmittance and chemical stability on the surface of non-metallic carbon nanotubes, a carbon-based bismuth oxyhalide interfacial heterostructure has been constructed to efficiently and selectively remove pollutants in water. Due to its adjustable geometric structure and electronic structure, easy separation of photo-generated electron-hole pairs, and mild and controllable photocatalytic reaction conditions, it has become an ideal candidate for photocatalysts for selective oxidation of pollutants. However, the active sites of the carbon-based bismuth oxyhalide photocatalyst have the problem of high exposure and the active components are difficult to be efficiently utilized, resulting in a decrease in photocatalytic activity. Therefore, how to improve the photocatalytic activity of the photocatalyst has become a technical problem to be solved urgently in this field. Therefore, constructing a multi-level confined structure composite photocatalytic material with porous carbon nanotube bismuth as the core provides an important scientific basis and method reference for the efficient treatment of new pollutants in real water environment and the guarantee of water ecological safety. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method and application of a defective carbon nanotube bismuth-based composite photocatalytic material. The carbon nanotube bismuth-based composite photocatalytic material provided by the present invention has excellent photocatalytic performance.

[0004] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a carbon nanotube bismuth-based composite photocatalytic material, including bismuth oxyhalide and modified carbon nanotubes loaded on the bismuth oxyhalide;

[0006] The modified carbon nanotubes are multi-walled carbon nanotubes etched by plasma.

[0007] Preferably, the plasma etching time is 60-180 min.

[0008] Preferably, the plasma etching gas is argon, nitrogen or oxygen, and the gas flow rate is 300-500 mL / min.

[0009] The present invention also provides a preparation method of the carbon nanotube bismuth-based composite photocatalytic material described in the above technical solution, including the following steps:

[0010] (1) Mix a bismuth precursor solution, a halogen precursor solution and modified carbon nanotubes to obtain a dispersion;

[0011] (2) Hydrothermally treat the dispersion obtained in step (1) to obtain a carbon nanotube bismuth-based composite photocatalytic material.

[0012] Preferably, in step (1), the mixing temperature is room temperature and the mixing time is 45 - 90 min.

[0013] Preferably, in step (2), the hydrothermal treatment temperature is 90 - 180 °C and the hydrothermal treatment time is 12 - 24 h.

[0014] The present invention also provides a preparation method of a defective-rich carbon nanotube bismuth-based composite photocatalytic material, including:

[0015] Perform plasma etching on the carbon nanotube bismuth-based composite photocatalytic material described in the above technical solution or the carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method described in the above technical solution to obtain a defective-rich carbon nanotube bismuth-based composite photocatalytic material.

[0016] The present invention also provides a defective-rich carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method described in the above technical solution.

[0017] The present invention also provides the application of the carbon nanotube bismuth-based composite photocatalytic material described in the above technical solution, or the carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method described in the above technical solution, or the defective-rich carbon nanotube bismuth-based composite photocatalytic material in the degradation of pollutants under visible light.

[0018] Preferably, the pollutants include one of tetracycline, bisphenol A, endocrine disruptors, and antibiotics.

[0019] Preferably, the application of the carbon nanotube bismuth-based composite photocatalytic material or the defective-rich carbon nanotube bismuth-based composite photocatalytic material in the degradation of pollutants under visible light is: mix the carbon nanotube bismuth-based composite photocatalytic material or the defective-rich carbon nanotube bismuth-based composite photocatalytic material with a pollutant solution, then perform adsorption under dark conditions, and then perform a photocatalytic reaction under visible light.

[0020] The present invention provides a carbon nanotube bismuth-based composite photocatalytic material, which includes bismuth oxyhalide and modified carbon nanotubes loaded on the bismuth oxyhalide; the modified carbon nanotubes are multi-walled carbon nanotubes etched by plasma. The present invention utilizes the interfacial coupling effect of multi-walled carbon nanotubes to expand the absorption spectrum of bismuth oxyhalide and inhibit the recombination of carriers, thereby improving the photocatalytic performance; plasma etching is used to generate structural defects on the surface of multi-walled carbon nanotubes, increase the adsorption efficiency of active sites, and enhance the electron transfer performance of the carbon nanotube bismuth-based composite photocatalytic material, thereby improving the photocatalytic performance. Experimental results show that the defective carbon nanotube bismuth-based composite photocatalytic material provided by the present invention can achieve a degradation efficiency of 99.92% for bisphenol A under visible light irradiation. Description of the Drawings

[0021] Figure 1 Curves of the photocatalytic degradation performance of bisphenol A for Application Examples 1-2 and Comparative Application Example 1.

[0022] Figure 2 Curves of the photocatalytic degradation performance of bisphenol A for Application Examples 3-4;

[0023] Figure 3 SEM characterization diagram of the carbon nanotube bismuth-based composite photocatalytic material prepared in Example 2. Detailed Embodiments

[0024] The present invention provides a carbon nanotube bismuth-based composite photocatalytic material, which includes bismuth oxyhalide and modified carbon nanotubes loaded on the bismuth oxyhalide;

[0025] The modified carbon nanotubes are multi-walled carbon nanotubes etched by plasma.

[0026] In the present invention, the carbon nanotube bismuth-based composite photocatalytic material includes bismuth oxyhalide. In the present invention, the bismuth oxyhalide is the active component.

[0027] In the present invention, the carbon nanotube bismuth-based composite photocatalytic material further includes modified carbon nanotubes loaded on the bismuth oxyhalide.

[0028] In the present invention, the modified carbon nanotubes are multi-walled carbon nanotubes etched by plasma. The present invention introduces plasma etching to realize the controllable preparation of active sites to ensure the efficient production of active species, thereby improving the selective removal of pollutants; the defects introduced by plasma etching enhance the adsorption efficiency and electron transfer performance of the carbon nanotube bismuth-based composite photocatalytic material, providing a new idea for the surface modification of the carbon nanotube bismuth-based composite photocatalytic material.

[0029] In the present invention, the time of the plasma etching is preferably 60 - 180 min, more preferably 80 - 150 min, and still more preferably 100 - 120 min; the gas for the plasma etching is preferably argon, nitrogen or oxygen; the flow rate of the gas is preferably 300 - 500 mL / min, more preferably 350 - 400 mL / min. By limiting the process parameters of the plasma etching within the above ranges, the present invention can improve the pore-forming effect, thereby increasing the adsorption efficiency of the active sites, enhancing the electron transfer performance of the carbon nanotube bismuth-based composite photocatalytic material, and further improving the photocatalytic performance.

[0030] In the present invention, the plasma etching is preferably carried out in a plasma etching machine reactor. The present invention has no special limitation on the model of the plasma etching machine reactor, and any instrument and equipment well-known to those skilled in the art can be used.

[0031] In the present invention, the length of the multi-walled carbon nanotubes is preferably 10 - 30 μm; the outer diameter of the multi-walled carbon nanotubes is preferably 10 - 20 nm; the inner diameter of the multi-walled carbon nanotubes is preferably 5 - 10 nm.

[0032] The present invention utilizes the interfacial coupling effect of the multi-walled carbon nanotubes to expand the absorption spectrum of bismuth oxyhalide and inhibit the recombination of carriers, thereby improving the photocatalytic performance; plasma etching is used to generate structural defects on the surface of the multi-walled carbon nanotubes, increasing the adsorption efficiency of the active sites and enhancing the electron transfer performance of the carbon nanotube bismuth-based composite photocatalytic material, thereby improving the photocatalytic performance.

[0033] The present invention also provides a preparation method of the carbon nanotube bismuth-based composite photocatalytic material according to the above technical solution, comprising the following steps:

[0034] (1) Mixing a bismuth precursor solution, a halogen precursor solution and modified carbon nanotubes to obtain a dispersion;

[0035] (2) Hydrothermally treating the dispersion obtained in step (1) to obtain the carbon nanotube bismuth-based composite photocatalytic material.

[0036] The present invention has no special limitation on the sources of the respective raw materials, and any commercially available products well-known to those skilled in the art or products prepared by well-known preparation methods can be used.

[0037] The present invention mixes a bismuth precursor solution, a halogen precursor solution and modified carbon nanotubes to obtain a dispersion

[0038] In the present invention, the bismuth precursor solution is preferably an ethylene glycol solution of a bismuth precursor; the bismuth precursor is preferably a bismuth salt, more preferably bismuth nitrate. In the present invention, the bismuth precursor is used to provide the bismuth required in the bismuth oxyhalide.

[0039] In the present invention, the concentration of the bismuth precursor solution is preferably 0.1 to 0.5 mmol / L, more preferably 0.2 mmol / L. The present invention has no special limitation on the preparation method of the bismuth precursor solution, and the operations well-known to those skilled in the art can be adopted.

[0040] In the present invention, the halogen precursor solution is preferably an ethylene glycol solution of a halogen precursor; the halogen precursor is preferably at least one of potassium iodide, potassium chloride, sodium chloride, sodium bromide, potassium bromide, 1-hexadecyl-3-methylimidazolium bromide, and 1-hexadecyl-3-methylimidazolium chloride. The present invention has no special limitation on the preparation method of the halogen precursor solution, and the operations well-known to those skilled in the art can be adopted. In the present invention, the halogen precursor is used to provide the halogen required in bismuth oxyhalide.

[0041] The present invention has no special limitation on the concentration of the halogen precursor solution, as long as the halogen precursor is completely dissolved.

[0042] In the present invention, the molar ratio of the bismuth precursor to the halogen precursor is preferably (1 to 2):(1 to 2), more preferably 1:1. Limiting the molar ratio of the bismuth precursor to the halogen precursor within the above range in the present invention can improve the yield of bismuth oxyhalide.

[0043] In the present invention, the mass of the modified carbon nanotubes is preferably 1 to 10% of the total mass of the bismuth precursor solution and the modified carbon nanotubes, more preferably 2 to 5%.

[0044] In the present invention, the mixing of the bismuth precursor solution, the halogen precursor solution, and the modified carbon nanotubes is preferably to mix the bismuth precursor solution with the modified carbon nanotubes first, and then add the halogen precursor solution for mixing. Adopting the above mixing method in the present invention can improve the mixing degree of each material.

[0045] In the present invention, the mixing of the bismuth precursor solution and the modified carbon nanotubes is preferably carried out under ultrasonic conditions; the power of the ultrasonic wave is preferably 400 to 600 W, more preferably 450 to 550 W; the time of the ultrasonic wave is preferably 15 to 45 min, more preferably 20 to 30 min. By limiting the process parameters of the ultrasonic wave within the above range in the present invention, the raw materials can be mixed more uniformly.

[0046] In the present invention, the mixing of adding the halogen precursor solution is preferably carried out under stirring conditions; the temperature of the stirring is preferably room temperature; the time of the stirring is preferably 45 to 90 min, more preferably 60 to 80 min. The present invention has no special limitation on the stirring rate, as long as the materials are mixed evenly. Controlling the process parameters of the stirring within the above range in the present invention can make the materials mixed more evenly.

[0047] After obtaining the dispersion liquid, the present invention performs hydrothermal treatment on the dispersion liquid to obtain a carbon nanotube bismuth-based composite photocatalytic material.

[0048] In the present invention, the temperature of the hydrothermal treatment is preferably 90 - 180 °C, more preferably 100 - 160 °C; the time of the hydrothermal treatment is preferably 12 - 24 h, more preferably 12 - 18 h. Controlling the process parameters of the hydrothermal treatment within the above range in the present invention can improve the efficiency of the hydrothermal treatment.

[0049] After the hydrothermal treatment is completed, the present invention preferably washes and dries the product obtained by the hydrothermal treatment in sequence to obtain a carbon nanotube bismuth-based composite photocatalytic material. Washing adopted in the present invention can wash away the unreacted substances in the product.

[0050] The present invention has no special limitation on the operation of the washing, as long as the unreacted raw materials are removed.

[0051] In the present invention, the temperature of the drying is preferably 60 - 90 °C, more preferably 60 - 70 °C. The present invention has no special limitation on the time of the drying, and it can be dried to constant weight.

[0052] The carbon nanotube bismuth-based composite photocatalytic material provided by the present invention provides an important scientific basis and method reference for the efficient treatment of pollutants in the real water environment and the guarantee of water ecological safety.

[0053] The present invention prepares a carbon nanotube bismuth-based composite photocatalytic material with highly exposed active sites by plasma etching, realizing the controllable construction of the types, densities, and functional groups of active sites at the nanoscale. At the same time, the porous structure can also shorten the migration distance of photogenerated carriers, contributing to the generation of active species.

[0054] The carbon nanotube bismuth-based composite photocatalytic material prepared by the present invention has excellent degradation effect on pollutants under visible light irradiation, far superior to single bismuth oxyiodide material and carbon-based photocatalytic material without plasma etching, and has great application potential.

[0055] The present invention also provides a preparation method of a carbon nanotube bismuth-based composite photocatalytic material with rich defects, including:

[0056] Performing plasma etching on the carbon nanotube bismuth-based composite photocatalytic material described in the above technical solution or the carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method described in the above technical solution to obtain a carbon nanotube bismuth-based composite photocatalytic material with rich defects.

[0057] In the present invention, the time of the plasma etching is preferably 60 to 180 min, more preferably 120 min; the gas for the plasma etching is preferably argon, nitrogen, hydrogen or oxygen, more preferably argon; the flow rate of the gas is preferably 300 to 500 mL / min, more preferably 350 to 400 mL / min. The present invention uses plasma etching to enable the carbon nanotube bismuth-based composite photocatalytic material to have a defective structure, thereby improving the photocatalytic performance of the defective carbon nanotube bismuth-based composite photocatalytic material.

[0058] The present invention also provides a defective carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method described in the above technical solution.

[0059] The present invention also provides an application of the carbon nanotube bismuth-based composite photocatalytic material described in the above technical solution, or the carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method described in the above technical solution, or the defective carbon nanotube bismuth-based composite photocatalytic material in the degradation of pollutants under visible light.

[0060] In the present invention, the pollutant preferably includes one of tetracycline, bisphenol A, endocrine disruptors and antibiotics; the antibiotic preferably includes antipyrine and ofloxacin.

[0061] In the present invention, the application of the carbon nanotube bismuth-based composite photocatalytic material or the defective carbon nanotube bismuth-based composite photocatalytic material in the degradation of pollutants under visible light is preferably: mixing the carbon nanotube bismuth-based composite photocatalytic material or the defective carbon nanotube bismuth-based composite photocatalytic material with a pollutant solution, and then performing adsorption under dark conditions first, and then performing a photocatalytic reaction under visible light.

[0062] In the present invention, the pollutant solution is preferably an aqueous solution of the pollutant; the concentration of the pollutant solution is preferably 0.01 to 5 mmol / L, more preferably 0.03 to 0.08 mmol / L; the mass ratio of the carbon nanotube bismuth-based composite photocatalytic material to the volume of the pollutant solution is preferably (1 to 10) mg:(5 to 50) mL, more preferably (1.5 to 5) mg:(10 to 20) mL; the mass ratio of the defective carbon nanotube bismuth-based composite photocatalytic material to the volume of the pollutant solution is preferably (1 to 10) mg:(5 to 50) mL, more preferably (1.5 to 5) mg:(10 to 20) mL. The present invention limits the mass ratio of the carbon nanotube bismuth-based composite photocatalytic material / the defective carbon nanotube bismuth-based composite photocatalytic material to the volume of the pollutant solution within the above range to improve the degradation efficiency of the pollutant.

[0063] As an implementation manner, the mass ratio of the carbon nanotube bismuth-based composite photocatalytic material to the volume of the pollutant solution can be 3 mg: 20 mL; the mass ratio of the defective-rich carbon nanotube bismuth-based composite photocatalytic material to the volume of the pollutant solution can be 2 mg: 20 mL.

[0064] The present invention has no special limitation on the operation of mixing the carbon nanotube bismuth-based composite photocatalytic material or the defective-rich carbon nanotube bismuth-based composite photocatalytic material with the pollutant solution, and the technical solutions for preparing the mixed material well-known to those skilled in the art can be adopted.

[0065] In the present invention, the adsorption is preferably carried out under stirring conditions; the adsorption time is preferably 30 to 60 min, more preferably 40 to 50 min; the adsorption temperature is preferably room temperature. The present invention has no special limitation on the stirring rate, and it is sufficient to reach the adsorption equilibrium.

[0066] In the present invention, the visible light is preferably provided by a xenon lamp; the power of the xenon lamp is preferably 300 to 800 W, more preferably 500 W.

[0067] In the present invention, the photocatalytic reaction time is preferably 1 to 2 h, more preferably 1.5 to 2 h. The present invention controls the photocatalytic reaction time within the above range, which is more conducive to the progress of the photocatalytic reaction.

[0068] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. 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 in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0069] Example 1

[0070] A carbon nanotube bismuth-based composite photocatalytic material is composed of bismuth oxyhalide and modified carbon nanotubes supported on the bismuth oxyhalide;

[0071] The modified carbon nanotubes are multi-walled carbon nanotubes etched by plasma;

[0072] The preparation method of the carbon nanotube bismuth-based composite photocatalytic material is the following steps:

[0073] (1) Evenly spread 30 mg of multi-walled carbon nanotubes on the inner surface of a glass petri dish, and then place it in a plasma etching machine reactor, introduce argon at a rate of 300 mL / min for plasma etching for 60 min to obtain modified carbon nanotubes; wherein, the length of the multi-walled carbon nanotubes is 10 to 30 μm, the outer diameter is 10 to 20 nm, and the inner diameter is 5 to 10 nm;

[0074] (2) Dissolve 2 mmol of bismuth nitrate pentahydrate in 40 mL of ethylene glycol and ultrasonicate for 30 min to obtain a bismuth precursor solution; wherein, the power of ultrasonication is 500 W;

[0075] (3) Disperse the modified carbon nanotubes obtained in step (1) in the bismuth precursor solution obtained in step (2) under ultrasonication at 400 W for 30 min, then add 2 mmol of potassium iodide dissolved in ethylene glycol to the mixture, and stir at room temperature for 60 min to obtain a mixed material; wherein, the molar ratio of bismuth nitrate pentahydrate to potassium iodide is 1:1; the modified carbon nanotubes are 2% of the total mass of the bismuth precursor solution and the modified carbon nanotubes;

[0076] (4) Carry out hydrothermal reaction on the mixed material obtained in step (3) in a reaction kettle at 160 °C for 12 h, then wash it alternately with deionized water and ethylene glycol 3 times, and then dry it at 60 °C to constant weight to obtain a carbon nanotube bismuth-based composite photocatalytic material, denoted as CB-2.

[0077] Comparative Example 1

[0078] On the basis of Example 1, carbon nanotubes are omitted and other conditions remain unchanged to obtain a photocatalytic material, denoted as BiOI.

[0079] Example 2

[0080] A preparation method of a carbon nanotube bismuth-based composite photocatalytic material with rich defects is as follows:

[0081] Perform plasma etching on the carbon nanotube bismuth-based composite photocatalytic material prepared in Example 1 for 120 min to obtain a carbon nanotube bismuth-based composite photocatalytic material with rich defects, denoted as Ar-CB-2; wherein, the gas for plasma etching is argon; the flow rate of the argon is 350 mL / min.

[0082] Example 3

[0083] On the basis of Example 1, change the content of the modified carbon nanotubes, that is, the modified carbon nanotubes are 1% of the total mass of the bismuth precursor solution and the modified carbon nanotubes, and other conditions remain unchanged to obtain a carbon nanotube bismuth-based composite photocatalytic material, denoted as CB-1.

[0084] Example 4

[0085] On the basis of Example 1, change the content of the modified carbon nanotubes, that is, the modified carbon nanotubes are 5% of the total mass of the bismuth precursor solution and the modified carbon nanotubes, and other conditions remain unchanged to obtain a carbon nanotube bismuth-based composite photocatalytic material, denoted as CB-5.

[0086] Application Example 1

[0087] Using bisphenol A (BPA) as the test pollutant, the visible-light catalytic degradation test was carried out on the carbon nanotube bismuth-based composite photocatalytic material (carbon nanotube bismuth oxyiodide composite material) obtained in Example 1. The test method is as follows:

[0088] Prepare an aqueous solution of 100 mL of 5 mM bisphenol A, add 15 mg of the carbon nanotube bismuth-based composite photocatalytic material prepared in Example 1 to the above bisphenol A solution, stir for 60 min in the dark at room temperature to reach the adsorption equilibrium, and then use a 500 W xenon lamp as the visible light source to irradiate for 2 h to carry out the photocatalytic degradation reaction.

[0089] Application Example 2

[0090] The defective carbon nanotube bismuth-based composite photocatalytic material prepared in Example 2 was used to carry out the photocatalytic degradation reaction according to the test method of Application Example 1.

[0091] Application Example 3

[0092] The carbon nanotube bismuth-based composite photocatalytic material prepared in Example 3 was used to carry out the photocatalytic degradation reaction according to the test method of Application Example 1.

[0093] Application Example 4

[0094] The carbon nanotube bismuth-based composite photocatalytic material prepared in Example 4 was used to carry out the photocatalytic degradation reaction according to the test method of Application Example 1.

[0095] Comparative Application Example 1

[0096] The photocatalytic material prepared in Comparative Example 1 was used to carry out the photocatalytic degradation reaction according to the test method of Application Example 1.

[0097] Figure 1 Curves of the performance of photocatalytic degradation of bisphenol A for Application Examples 1-2 and Comparative Application Example 1.

[0098] From Figure 1 it can be seen that the degradation efficiency of Ar-CB-2 for BPA is significantly improved compared with CB-2 and BiOI; after 120 min of visible light irradiation, the degradation rate of BPA reaches 99.92%, and the results show that Ar-CB-2 has the best photocatalytic performance.

[0099] Figure 2 Curves of the performance of photocatalytic degradation of bisphenol A for Application Examples 3-4.

[0100] From Figure 2 it can be seen that with the increase of the content of modified carbon nanotubes, the photocatalytic performance of the carbon nanotube bismuth-based composite photocatalytic material gradually increases.

[0101] Figure 3SEM characterization diagram of the carbon nanotube bismuth-based composite photocatalytic material prepared in Example 2.

[0102] It can be seen from Figure 3 that multi-walled carbon nanotubes are inserted into bismuth oxyhalide particles, that is, multi-walled carbon nanotubes are loaded on bismuth oxyhalide particles.

[0103] It can be seen from the above examples and comparative examples that the carbon nanotube bismuth-based composite photocatalytic material provided by the present invention has excellent photocatalytic performance.

[0104] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A carbon nanotube bismuth-based composite photocatalytic material, comprising bismuth oxyhalide and modified carbon nanotubes supported on the bismuth oxyhalide; The modified carbon nanotubes are multi-walled carbon nanotubes etched by plasma.

2. The carbon nanotube bismuth-based composite photocatalytic material according to claim 1, characterized in that: The plasma etching time is 60 to 180 minutes.

3. The carbon nanotube bismuth-based composite photocatalytic material according to claim 1 or 2, characterized in that: The plasma etching gas is argon, nitrogen or oxygen, and the flow rate of the gas is 300-500 mL / min.

4. The method for preparing the carbon nanotube bismuth-based composite photocatalytic material according to any one of claims 1 to 3, comprising the following steps: (1) mixing a bismuth precursor solution, a halogen precursor solution and modified carbon nanotubes to obtain a dispersion; (2) The dispersion obtained in step (1) is subjected to hydrothermal treatment to obtain a carbon nanotube bismuth-based composite photocatalytic material.

5. The preparation method according to claim 4, characterized in that: The temperature of the hydrothermal treatment in step (2) is 90 to 180° C., and the time of the hydrothermal treatment is 12 to 24 hours.

6. A method for preparing a defect-rich carbon nanotube bismuth-based composite photocatalytic material, comprising: The carbon nanotube bismuth-based composite photocatalyst material according to any one of claims 1 to 3 or the carbon nanotube bismuth-based composite photocatalyst material prepared by the preparation method according to any one of claims 4 to 5 is subjected to plasma etching to obtain a defect-rich carbon nanotube bismuth-based composite photocatalyst material.

7. The defect-rich carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method of claim 6.

8. Use of the carbon nanotube bismuth-based composite photocatalytic material according to any one of claims 1 to 3, the carbon nanotube bismuth-based composite photocatalytic material prepared by the preparation method according to any one of claims 4 to 5, or the defect-rich carbon nanotube bismuth-based composite photocatalytic material according to claim 7 in the degradation of pollutants under visible light.

9. The use according to claim 8, characterized in that: The contaminants include one of tetracycline, bisphenol A, endocrine disruptors and antibiotics.

10. The use according to claim 8, characterized in that: The application of the carbon nanotube bismuth-based composite photocatalytic material or the defect-rich carbon nanotube bismuth-based composite photocatalytic material in the degradation of pollutants under visible light is: mixing the carbon nanotube bismuth-based composite photocatalytic material or the defect-rich carbon nanotube bismuth-based composite photocatalytic material with a pollutant solution, then adsorbing it under dark conditions, and then performing a photocatalytic reaction under visible light.

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