Preparation method of modified zinc oxide nanotube catalytic material

Abstract

The invention discloses a preparation method of a modified zinc oxide nanotube catalytic material, and belongs to the technical field of photocatalytic materials. The preparation method comprises the following steps: preparing a one-dimensional zinc-based organic frame structure from deionized water, alcohol, an organic solvent, an alkaline solid and zinc salt, then mixing a colloidal solution with photocatalytic characteristics with the one-dimensional zinc-based organic frame structure to obtain a modified one-dimensional zinc-based organic frame structure composite material, and finally calcining in an oxygen-inert gas mixed atmosphere to obtain the composite material with the one-dimensional zinc-based organic frame structure. The tubular catalytic material composed of the modified zinc oxide nanoparticles is obtained. According to the invention, a one-dimensional zinc-based organic framework structure is constructed, and the tubular catalytic material composed of zinc oxide and narrow-band gap semiconductor modified zinc oxide nanoparticles is synthesized by using a calcination method, so that the synthesis method is simple to operate, relatively low in cost and small in waste generation amount, and the problems that a nanoparticle catalyst is easy to agglomerate, low in catalytic efficiency and the like can be solved; therefore, the tubular photocatalytic material composed of ZnO nano-particles with efficient photocatalytic activity is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic materials, and particularly to a preparation method of a modified zinc oxide nanotube catalytic material. Background Art

[0002] Due to its rich resources, low price, non-toxicity, and excellent optoelectronic properties, zinc oxide has become a commonly used photocatalytic material. In particular, through means such as doping, semiconductor compounding, modification, and carrier loading, the photocatalytic performance of zinc oxide can be further improved. One-dimensional zinc oxide nanostructures have attracted the research interest of many scientific workers due to their novel optoelectronic, physicochemical, and biological properties, and have been widely used in fields such as electronics, photocatalysis, sensing, water treatment, environmental protection, air purification, field emission, and solar cells.

[0003] Currently, most one-dimensional zinc oxide materials are prepared by methods such as microemulsion, pyrolysis, hydrothermal, template, solvothermal, microwave heating, and sol-gel. These methods have defects such as complex processes, high energy consumption, low yield, difficulty in large-scale production, or release of toxic gases. Therefore, it is very necessary to develop an energy-saving and environmentally friendly preparation method for one-dimensional zinc oxide nanomaterials. Metal-organic framework materials (MOFs) composed of metal ions as connection points and organic ligands as supports have advantages such as high porosity, low density, large specific surface area, regular pore channels, adjustable pore diameters, and topological structure diversity and tailoring, and are one of the ideal template materials for preparing one-dimensional oxide nanomaterials, thus attracting great attention from scientific workers.

[0004] Using MOFs as raw materials, oxide nanoparticles, nanowires, nanorods and other nanomaterials with porous characteristics, as well as various shaped porous carbon / metal oxide composites have been successfully prepared. However, since MOFs materials contain organic polymers, the organic polymers are easily decomposed during the calcination process, and the oxidation rate of the organic matter does not match the formation rate of the oxide, resulting in difficulty in maintaining the original morphology, and thus it is difficult for the product to form oxide nanotubes. In addition, as a photocatalytic material, zinc oxide has a high band gap energy, but low utilization rate of visible light and high recombination of photo-generated electron-hole pairs, resulting in low photocatalytic efficiency, which limits its practical application. Therefore, the present invention proposes a modified preparation method for zinc oxide nanotube materials. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a modified zinc oxide nanotube catalytic material. Using one-dimensional zinc-based MOFs materials as raw materials, a tubular catalytic material composed of zinc oxide nanoparticles and a tubular photocatalytic material composed of narrow-bandgap oxides in-situ modified zinc oxide nanoparticles are obtained through simple calcination treatment, solving problems such as easy agglomeration of nano-zinc oxide particles and low catalytic activity, and improving the photocatalytic performance of zinc oxide nanotubes.

[0006] To achieve the above object, the present invention provides a method for preparing a modified zinc oxide nanotube catalytic material, comprising the following steps:

[0007] (1) Under continuous stirring conditions, pure anhydrous ethanol and an organic solvent are added to deionized water, and ultrasonic stirring is carried out to obtain a uniformly dispersed mixed solution;

[0008] (2) An alkaline solid is added to the mixed solution obtained in step (1), and stirring is carried out to obtain an alkaline organic mixed solution;

[0009] (3) Under continuous magnetic stirring conditions, an organic ligand is added to the alkaline organic mixed solution obtained in step (2), and stirring is carried out to obtain a uniform organic ligand mixed solution;

[0010] (4) A solution containing a zinc salt is added to the organic ligand mixed solution obtained in step (3), and after stirring, it is allowed to stand to obtain a zinc-based metal-organic framework structure precipitation solution. After centrifugal washing and drying, it is ground to obtain a zinc-based metal-organic framework structure powder;

[0011] (5) The zinc-based metal-organic framework structure powder obtained in step (4) is added to a narrow bandgap oxide precursor colloidal solution, ultrasonic stirring is carried out, and then filtration is carried out. The precipitate is dried and ground to obtain a modified zinc-based metal-organic framework structure powder;

[0012] (6) The modified zinc-based metal-organic framework structure powder obtained in step (5) is calcined in a mixed atmosphere of oxygen and an inert gas to obtain a tubular catalytic material composed of modified zinc oxide nanoparticles.

[0013] Preferably, in step (1), the organic solvent is any one or two of DMF or dimethyl sulfoxide;

[0014] The volume of pure anhydrous ethanol is 40 - 60 mL, the volume of the organic solvent is 6 - 10 mL, and the volume of deionized water is 100 - 150 mL; the time of ultrasonic stirring is 15 - 30 min.

[0015] Preferably, in step (2), the alkaline solid is any one or two of NaOH or KOH;

[0016] The dosage of the alkaline solid is 2.4 - 4.8 g; the stirring time is 15 - 20 min.

[0017] Preferably, in step (3), the organic ligand is any one or more of H3BTC, EDTA or ethylenediamine;

[0018] The dosage of the organic ligand is 0.2 - 0.5 g; the stirring time is 15 - 20 min.

[0019] Preferably, in step (4), the zinc salt is any one or more of zinc nitrate, zinc acetate or zinc sulfate, the dosage of the zinc salt is 0.6 - 0.8 g, and the volume of the zinc salt solution is 20 - 40 mL.

[0020] Preferably, in step (4), the stirring time is 15 - 30 min, the standing time is 12 - 24 h; the drying temperature is 50 - 70 °C, and the drying time is 5 - 7 h.

[0021] Preferably, in step (5), the narrow-bandgap oxide precursor is any one or a mixture of tungstic acid, europium hydroxide or samarium hydroxide, and the volume of the narrow-bandgap oxide precursor colloidal solution is 50 - 150 mL.

[0022] Preferably, in step (5), the ultrasonic stirring time is 15 - 30 min; the drying temperature is 50 - 70 °C, and the drying time is 5 - 7 h.

[0023] Preferably, in step (6), the flow rate ratio of oxygen to inert gas is 1:100 - 1:10; the calcination temperature is 450 - 600 °C, and the calcination time is 3 - 5 h.

[0024] The present invention also provides a modified zinc oxide nanotube catalytic material prepared by the above preparation method.

[0025] The present invention utilizes an organic ligand to generate an anionic ligand under alkaline conditions, and then forms a structurally stable one-dimensional zinc-based organic framework structure with the zinc ions of the zinc salt. Then, by controlling the oxygen content and calcination temperature during the calcination process, the oxidation rate of the organic matter is matched with the oxide formation rate during the decomposition of the precursor organic matter, and finally a tubular structure composed of zinc oxide nanoparticles is obtained. At the same time, by modifying with a narrow-bandgap oxide precursor, an oxide-modified tubular catalytic material composed of zinc oxide nanoparticles is in-situ synthesized, broadening the spectral response range of the zinc oxide nanotubes, reducing the recombination of photo-generated electron-hole pairs, and improving the photocatalytic efficiency of the zinc oxide nanotubes, obtaining a tubular catalytic material composed of zinc oxide nanoparticles with high catalytic activity and good stability.

[0026] Therefore, the preparation method of a modified zinc oxide nanotube catalytic material provided by the present invention has the following beneficial effects:

[0027] (1) The present invention prepares a structurally stable one-dimensional zinc-based organic framework structure by the co-precipitation method at room temperature, and then by controlling the oxygen content under the reaction conditions, adjusts the oxidation rate of the organic ligand in the zinc-based organic framework structure, so that the decomposition of the precursor organic matter and the formation rate of zinc oxide are matched, and finally a tubular catalytic material composed of zinc oxide nanoparticles is formed.

[0028] (2) Based on the synthesis of a structurally stable one-dimensional zinc-based organic framework structure, the present invention uses a narrow-bandgap semiconductor precursor colloidal solution for modification to form a modified one-dimensional zinc-based organic framework structure, and then in-situ synthesizes a tubular photocatalytic material composed of zinc oxide nanoparticles modified by a narrow-bandgap semiconductor through calcination.

[0029] (3) The present invention in-situ constructs a tubular heterojunction of zinc oxide nanoparticles through modification and calcination treatment, which not only broadens the spectral response range of zinc oxide, reduces the recombination of photo-generated electron-hole pairs, and improves the photocatalytic efficiency, but also makes it have a broader application prospect in the fields of photocatalysis, energy, sewage treatment, environmental protection, etc. In addition, the synthesis method of the present invention has simple steps, is convenient to control its morphology and structure, and is easy to operate, having the advantages of industrial promotion.

[0030] The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments. Description of the Drawings

[0031] Figure 1 It is the SEM image of the ZnO nanotube catalytic material obtained in Example 1, where (a) is the low-magnification SEM image at 10 μm; (b) is the high-magnification SEM image at 1 μm.

[0032] Figure 2 It is the photocatalytic performance of the ZnO nanotube catalytic material and the Sm2O3 / ZnO nanotube catalytic material obtained in Example 2 under simulated sunlight.

[0033] Figure 3 It is the XRD pattern of the ZnO nanotube catalytic material and the Eu2O3 / ZnO nanotube catalytic material obtained in Example 3.

[0034] Figure 4 The SEM image of the WO3 / ZnO nanotube catalytic material obtained in Example 4, where (a) is the low-magnification SEM image at 10 μm; (b) is the high-magnification SEM image at 1 μm. Detailed Embodiments

[0035] The technical solution of the present invention will be further described below through the accompanying drawings and embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application and belong to the protection scope of the present invention.

[0036] References to "embodiments" in this document mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The term "embodiment" that appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it particularly limited to its independence or relevance to other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0037] Unless otherwise defined, the meanings of the technical terms used in this document are the same as those commonly understood by those skilled in the technical field to which this application belongs; the use of the relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0038] Unless otherwise specified in the present invention, the reagents, instruments, equipment, etc. used are the reagents, instruments, and equipment commonly used by those skilled in the art.

[0039] Example 1

[0040] This example provides a method for preparing a zinc oxide nanotube catalytic material, which specifically includes the following steps:

[0041] (1) Under continuous stirring, 40 mL of pure anhydrous ethanol and 6 mL of DMF are added to 100 mL of deionized water, and ultrasonically stirred for 15 min to obtain a uniformly dispersed mixed solution;

[0042] (2) 2.4 g of solid NaOH is added to the mixed solution obtained in the above step (1), and after stirring for 15 min, the obtained NaOH / DMF mixed solution;

[0043] (3) Under continuous magnetic stirring, 0.2 g of ethylenediamine is added to the NaOH / DMF mixed solution obtained in step (2), and after stirring for 15 min, a uniform ethylenediamine mixed solution is obtained;

[0044] (4) 20 mL of a solution containing 0.6 g of zinc sulfate is added to the ethylenediamine mixed solution obtained in step (3), stirred for 15 min and then left standing for 12 h to obtain a zinc-based organic framework structure precipitation solution. After centrifugal cleaning, a clean zinc-based organic framework structure precipitate is obtained, and the precipitate is placed in a drying oven at 50 °C for 5 h, and after grinding, a zinc-based organic framework structure powder is obtained;

[0045] (5) The zinc-based organic framework structure powder obtained in step (4) is calcined in a mixed gas of oxygen and inert gas (the flow ratio of oxygen to inert gas is 1:100) for 3 h, and the calcination temperature is 450 °C, and finally a zinc oxide nanotube catalytic material is obtained.

[0046] Figure 1 SEM image of the ZnO nanotube catalytic material obtained in Example 1. It can be observed from the figure that the obtained sample has a tubular structure formed by the aggregation of a large number of particles, with a smooth surface and a compact structure. Its cross-section shows a square opening with a side length of about 2 μm.

[0047] Example 2

[0048] This example provides a preparation method for a zinc oxide nanotube catalytic material and a Sm2O3-modified zinc oxide nanotube catalytic material, which specifically includes the following steps:

[0049] (1) Under continuous stirring, add 50 mL of pure anhydrous ethanol and 80 mL of DMF to 130 mL of deionized water, and ultrasonically stir for 20 min to obtain a uniformly dispersed mixed solution;

[0050] (2) Add 2.8 g of KOH to the mixed solution obtained in the above step (1), and after stirring for 15 min, obtain a KOH-DMF mixed solution;

[0051] (3) Under continuous magnetic stirring, add 0.3 g of EDTA to the KOH-DMF mixed solution obtained in step (2), and after stirring for 18 min, obtain a uniform EDTA mixed solution;

[0052] (4) Add 30 mL of a solution containing 0.7 g of zinc nitrate to the EDTA mixed solution obtained in step (3), stir for 20 min and then let it stand for 20 h to obtain a zinc-based organic framework structure precipitation solution. After centrifugal washing, obtain a clean zinc-based organic framework structure precipitate, and place this precipitate in a drying oven at 60 °C for 6 h. After grinding, obtain zinc-based organic framework structure powder;

[0053] (5) Add the zinc-based organic framework structure powder obtained in step (4) to 50 mL of a samarium hydroxide colloid solution, ultrasonically stir for 30 min, then filter the precipitation solution, and place this precipitate in a drying oven at 70 °C for 5 h. After grinding, obtain a modified zinc-based organic framework structure powder;

[0054] (6) Calcinate the zinc-based organic framework structure powders obtained in step (4) and step (5) respectively under a mixed gas of oxygen and inert gas (the flow ratio of oxygen to inert gas is 1:50) for 5 h, and the calcination temperature is 550 °C. Finally, obtain zinc oxide nanotubes and Sm2O3-modified zinc oxide nanotube catalytic materials respectively.

[0055] Figure 2 Photocatalytic performance of the ZnO nanotube catalytic material and the Sm2O3 / ZnO nanotube catalytic material obtained in Example 2 under simulated sunlight. C0 is the initial concentration of organic pollutants in the solution, Ct is the concentration of organic pollutants in the solution at time t. As can be seen from Figure 2 it, within 120 min, the degradation rate of pure zinc oxide is about 46%, and with the modification of Sm2O3, the degradation rate of the obtained sample is increased by about 28% compared with the ZnO sample. This indicates that the modification of Sm2O3 can improve the photocatalytic performance of the ZnO sample.

[0056] Example 3

[0057] This example provides a preparation method for a zinc oxide nanotube catalytic material and a Eu2O3-modified zinc oxide nanotube catalytic material, which specifically includes the following steps:

[0058] (1) Under continuous stirring, add 60 mL of pure anhydrous ethanol and 10 mL of dimethyl sulfoxide to 150 mL of deionized water, and ultrasonically stir for 30 min to obtain a uniformly dispersed mixed solution;

[0059] (2) Add 2.4 g of solid NaOH and 2.4 g of solid KOH to the mixed solution obtained in the above step (1), and stir for 20 min to obtain a NaOH-KOH / dimethyl sulfoxide mixed solution;

[0060] (3) Under continuous magnetic stirring, add 0.5 g of the H3BTC and EDTA mixture to the NaOH-KOH / dimethyl sulfoxide mixed solution obtained in step (2), and stir for 20 min to obtain a uniform dimethyl sulfoxide mixed solution;

[0061] (4) Add 40 mL of a solution containing 0.8 g of zinc sulfate to the dimethyl sulfoxide mixed solution obtained in step (3), stir for 30 min and then let it stand for 24 h to obtain a zinc-based organic framework structure precipitation solution. After centrifugal cleaning, obtain a clean zinc-based organic framework structure precipitate, and place this precipitate in a drying oven at 70 °C for 7 h. After grinding, obtain zinc-based organic framework structure powder;

[0062] (5) Add the zinc-based organic framework structure powder obtained in step (4) to 150 mL of europium hydroxide colloidal solution, ultrasonically stir for 30 min, then filter the precipitation solution, and place this precipitate in a drying oven at 70 °C for 7 h. After grinding, obtain the modified zinc-based organic framework structure powder;

[0063] (6) Calcinate the zinc-based organic framework structure powders obtained in steps (4) and (5) respectively in a mixed gas of oxygen and inert gas (the flow ratio of oxygen to inert gas is 1:10) for 5 h, and the calcination temperature is 600 °C. Finally, obtain zinc oxide nanotubes and Eu2O3-modified zinc oxide nanotube catalytic materials respectively.

[0064] Figure 3XRD patterns of the ZnO nanotube catalytic material and the Eu2O3 / ZnO nanotube catalytic material obtained in Example 3. From Figure 3 it can be seen that obvious diffraction peaks appear at 2θ = 31.7°, 34.4°, 36.2°, 47.6°, 56.6°, 62.9° and 67.9° for both the ZnO and Eu2O3 / ZnO samples, corresponding to the diffraction peaks of the (100), (002), (101), (102), (110), (103) and (112) crystal planes of ZnO respectively. However, in the Eu2O3 / ZnO sample, in addition to the characteristic peaks of ZnO, diffraction peaks of the (211), (222) and (400) crystal planes of Eu2O3 appear at 2θ = 19.9°, 28.4° and 32.9° respectively, indicating that the obtained sample is a Eu2O3 / ZnO composite material.

[0065] Example 4

[0066] This example provides a preparation method for a zinc oxide nanotube catalytic material and a WO3-modified zinc oxide nanotube catalytic material, which specifically includes the following steps:

[0067] (1) Under continuous stirring, 45 mL of pure anhydrous ethanol and 8 mL of DMF are added to 120 mL of deionized water, and ultrasonically stirred for 30 min to obtain a uniformly dispersed mixed solution;

[0068] (2) 3.6 g of NaOH is added to the mixed solution obtained in the above step (1), and after stirring for 15 min, a NaOH / DMF mixed solution is obtained;

[0069] (3) Under continuous magnetic stirring, 0.4 g of H3BTC is added to the alkaline organic mixed solution obtained in step (2), and after stirring for 15 min, a uniform H3BTC mixed solution is obtained;

[0070] (4) 40 mL of a solution containing 0.6 g of zinc acetate is added to the H3BTC mixed solution obtained in step (3), stirred for 30 min and then left standing for 18 h to obtain a zinc-based organic framework structure precipitation solution. After centrifugation and washing, a clean zinc-based organic framework structure precipitate is obtained, and the precipitate is placed in a drying oven at 60 °C for 6 h and ground to obtain zinc-based organic framework structure powder;

[0071] (5) The zinc-based organic framework structure powder obtained in step (4) is added to 100 mL of tungstic acid colloid solution, ultrasonically stirred for 20 min, and then the precipitation solution is filtered. The precipitate is placed in a drying oven at 60 °C for 5 h and ground to obtain modified zinc-based organic framework structure powder;

[0072] (6) Calcinate the zinc-based organic framework structure powders obtained in steps (4) and (5) respectively in a mixed gas of oxygen and inert gas (the flow ratio of oxygen to inert gas is 1:20) for 3 h, and the calcination temperature is 500 °C. Finally, zinc oxide nanotubes and WO3-modified zinc oxide nanotube catalytic materials are obtained respectively.

[0073] Figure 4 SEM images of the ZnO nanotube catalytic material and the WO3 / ZnO nanotube catalytic material obtained in Example 4. As can be seen from Figure 4 it, the WO3 modification does not change the tubular structure of the sample, and its size does not change significantly, but the surface of the sample becomes rough, and a large number of particles aggregate on the surface. This result indicates that the WO3 modification does not change the shape of the ZnO nanotubes.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A preparation method of a modified zinc oxide nanotube catalytic material, characterized in that, It includes the following steps: (1) Under continuous stirring conditions, pure absolute ethanol and an organic solvent are added to deionized water, and ultrasonic stirring is carried out to obtain a uniformly dispersed mixed solution; (2) An alkaline solid is added to the mixed solution obtained in step (1), and stirring is carried out to obtain an alkaline organic mixed solution; (3) Under continuous magnetic stirring conditions, an organic ligand is added to the alkaline organic mixed solution obtained in step (2), and stirring is carried out to obtain a uniform organic ligand mixed solution; (4) A solution containing a zinc salt is added to the organic ligand mixed solution obtained in step (3), and after stirring, it is left standing to obtain a zinc-based metal-organic framework structure precipitation solution. After centrifugal washing and drying, it is ground to obtain zinc-based metal-organic framework structure powder; (5) The zinc-based metal-organic framework structure powder obtained in step (4) is added to a narrow-bandgap oxide precursor colloidal solution, ultrasonic stirring is carried out, then filtration is carried out, the precipitate is dried, and after grinding, modified zinc-based metal-organic framework structure powder is obtained; (6) The modified zinc-based metal-organic framework structure powder obtained in step (5) is calcined in a mixed atmosphere of oxygen and an inert gas to obtain a tubular catalytic material composed of modified zinc oxide nanoparticles.

2. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (1), the organic solvent is any one or two of DMF or dimethyl sulfoxide; The volume of pure absolute ethanol is 40 - 60 mL, the volume of the organic solvent is 6 - 10 mL, and the volume of deionized water is 100 - 150 mL; the ultrasonic stirring time is 15 - 30 min.

3. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (2), the alkaline solid is any one or two of NaOH or KOH; The dosage of the alkaline solid is 2.4 - 4.8 g; the stirring time is 15 - 20 min.

4. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (3), the organic ligand is any one or more of H3BTC, EDTA or ethylenediamine; The dosage of the organic ligand is 0.2 - 0.5 g; the stirring time is 15 - 20 min.

5. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (4), the zinc salt is any one or more of zinc nitrate, zinc acetate or zinc sulfate, the dosage of the zinc salt is 0.6 - 0.8 g, and the volume of the zinc salt solution is 20 - 40 mL.

6. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (4), the stirring time is 15 - 30 min, the standing time is 12 - 24 h; the drying temperature is 50 - 70 °C, and the drying time is 5 - 7 h.

7. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (5), the narrow-bandgap oxide precursor is any one or a mixture of tungstic acid, europium hydroxide or samarium hydroxide, and the volume of the narrow-bandgap oxide precursor colloidal solution is 50 - 150 mL.

8. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (5), the ultrasonic stirring time is 15 - 30 min; the drying temperature is 50 - 70 °C, and the drying time is 5 - 7 h.

9. The preparation method of a modified zinc oxide nanotube catalytic material according to claim 1, characterized in that: In step (6), the flow rate ratio of oxygen to the inert gas is 1:100 - 1:10; the calcination temperature is 450 - 600 °C, and the calcination time is 3 - 5 h.

10. A modified zinc oxide nanotube catalytic material, characterized in that: The modified zinc oxide nanotube catalytic material is prepared by the preparation method described in any one of claims 1 - 9.

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