A tungsten oxide hybrid nanorod photocatalyst, its preparation method and application

Abstract

The present invention discloses an ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst, a preparation method thereof, and an application thereof, belonging to the technical field of catalytic materials. The photocatalyst comprises a tungsten mesh and ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorods loaded on the surface of the tungsten mesh. The preparation method is as follows: the tungsten mesh is immersed in a mixed solution of concentrated nitric acid, hydrogen peroxide and water for an oxidation reaction; after the oxidation reaction is completed, the tungsten mesh is taken out, ammonium chloride is added to the remaining solution, stirred and dissolved, and then the taken-out tungsten mesh is added for a hydrothermal reaction, and the obtained product is washed and dried to obtain the tungsten oxide hybrid nanorod photocatalyst. The photocatalyst prepared by the present invention has strong photocatalytic performance. When used for removing toluene, toluene can be completely converted into CO<subgt;2< / subgt> and H<subgt;2< / subgt>O in a short time, and has excellent photocatalytic activity.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic materials, and particularly relates to a tungsten oxide hybrid nanorod photocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Common VOCs in daily life mainly include toluene, formaldehyde, etc. Among them, because benzene series compounds such as toluene have high toxicity and are prone to photochemical reactions with ozone, aromatic hydrocarbon compounds such as toluene and benzene have received more attention.

[0003] Photocatalytic oxidation technology is a clean, green, and pollution-free air purification technology. For volatile pollutants, photocatalytic oxidation technology not only has excellent catalytic removal effects under low-concentration pollutants, but also has great potential under high-concentration pollutants. The most significant feature of this technology is that it does not need to work under the ambient temperature with a large amount of energy supply. The irradiation of natural light can stimulate the photocatalyst to generate active free radicals, which can convert volatile pollutants into CO2 and H2O, meeting the requirements of building a resource-saving and environment-friendly society.

[0004] Tungsten oxides mainly include WO3 and WO2. Among them, because WO3 is a wide-bandgap semiconductor with a high electron-hole recombination rate, the photocatalytic efficiency is low. Therefore, how to prepare a photocatalyst material with better catalytic performance using tungsten oxides is a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] To solve the above problems in the prior art, the present invention provides a tungsten oxide hybrid nanorod photocatalyst, a preparation method thereof, and an application thereof. The tungsten oxide hybrid nanorod photocatalyst prepared by the present invention can be used as a catalyst in the process of removing toluene and can completely convert toluene into CO2 and H2O.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] Technical solution one of the present invention: The present invention provides a tungsten oxide hybrid nanorod photocatalyst, and the photocatalyst includes a tungsten mesh and ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorods loaded on the surface of the tungsten mesh.

[0008] Technical solution two of the present invention: The present invention also provides a preparation method of a tungsten oxide hybrid nanorod photocatalyst, including the following steps:

[0009] Soak the tungsten mesh in a mixed solution of concentrated nitric acid, hydrogen peroxide, and water for an oxidation reaction;

[0010] After the oxidation reaction is completed, take out the tungsten mesh, add ammonium chloride to the remaining solution, stir and dissolve it, then add the taken-out tungsten mesh for hydrothermal reaction, and wash and dry the obtained product to obtain the tungsten oxide hybrid nanorod photocatalyst.

[0011] Beneficial effects: During the soaking process of the present invention, strong oxidants (concentrated nitric acid and hydrogen peroxide) will etch the tungsten mesh. Then, during the hydrothermal reaction process, the catalyst tends to grow on the tungsten mesh, and the oxidants will not be completely consumed during the soaking process. During the hydrothermal reaction, the oxidants will further react with the tungsten mesh, thereby controlling the growth of nanorods on the surface of the tungsten mesh.

[0012] Furthermore, during the oxidation reaction, the volume ratio of the total volume of the concentrated nitric acid and hydrogen peroxide to the volume of water is (1 - 2)∶(40 - 60), wherein the volume ratio of the concentrated nitric acid to the hydrogen peroxide is (1 - 2)∶(1 - 3); the mass concentration of the concentrated nitric acid is 68 - 70%; the mass concentration of the hydrogen peroxide is 30 - 50%. The present invention controls the dosage of the oxidant to keep the pH value of the solution at 1, so that tungsten dioxide and tungsten trioxide coexist on the tungsten mesh and their morphology remains in the form of nanorods.

[0013] The soaking time is 0.5 h.

[0014] The pore size of the tungsten mesh is 80 - 100 mesh.

[0015] Beneficial effects: The present invention selects a tungsten mesh with a pore size of 80 - 100 mesh, which can not only prevent the small specific surface area caused by too low mesh number, but also prevent the small wire diameter when the mesh number is too large, avoiding the problem that the tungsten mesh is easily corroded and damaged during the reaction, and thus is beneficial to preparing an ammonium ion-modified tungsten dioxide - tungsten trioxide hybrid nanorod photocatalyst with excellent photocatalytic performance.

[0016] Furthermore, before the oxidation reaction, the tungsten mesh is first cut, washed and dried.

[0017] Furthermore, the cutting is to cut the tungsten mesh to a suitable size so that it can be placed in the hydrothermal reaction container. The present invention has no special limitation on the size of the tungsten mesh after cutting, and it can be adjusted according to the size of the hydrothermal reaction container.

[0018] The washing is as follows: First, place the cut tungsten mesh in a mixed solution of acetone and ethanol with a volume ratio of 1∶4, perform ultrasonic cleaning for 30 min at a power of 75 W, and then rinse with deionized water to remove impurities and grease on the surface of the tungsten mesh.

[0019] The drying method is drying with a hair dryer or cold air.

[0020] Further, the hydrothermal reaction is carried out in a reaction kettle with a polytetrafluoroethylene lining, and the amount of substance of ammonium chloride in the hydrothermal reaction process is 0.5 - 2 mmol.

[0021] The temperature of the hydrothermal reaction is 160 - 180 °C, and the reaction time is 12 - 24 h. In the present invention, controlling the temperature and time of the hydrothermal reaction within the above ranges is more conducive to the progress of the hydrothermal reaction.

[0022] Furthermore, the temperature of the hydrothermal reaction is preferably 160 - 170 °C, and the reaction time is 20 - 24 h.

[0023] Further, after the hydrothermal reaction is completed, the reagent used for washing the product is water; the drying is natural air drying or drying in an oven, preferably natural air drying. The natural air drying method adopted in the present invention can prevent the ammonium ion-modified dioxide-tungsten trioxide hybrid nanorod photocatalyst from denaturing.

[0024] The third technical solution of the present invention: The present invention also provides an application of a tungsten oxide hybrid nanorod photocatalyst in photocatalytic degradation of toluene.

[0025] Further, the specific process of the application is as follows: Place the tungsten oxide hybrid nanorod photocatalyst in a reactor, then introduce toluene into the reactor, and carry out a photocatalytic reaction to obtain CO2 and H2O.

[0026] Furthermore, the reactor is a quartz reactor.

[0027] The principle of the present invention: The present invention uses tungsten mesh as a self-sacrificial substrate, water as a reaction solvent, ammonium chloride as a structure-directing agent, concentrated nitric acid and hydrogen peroxide as oxidants, and reacts under hydrothermal conditions to obtain an ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst. First, the oxidants concentrated nitric acid and hydrogen peroxide oxidize the elemental tungsten on the tungsten mesh to generate tungstic acid. Then, after the oxidation reaction is completed, ammonium chloride and water are added and placed in a reaction kettle with a polytetrafluoroethylene lining for hydrothermal reaction. At this time, hybrid nanorods of tungsten dioxide and tungsten trioxide will be formed on the surface of the tungsten mesh and uniformly loaded on the surface of the tungsten mesh. The ammonium ions modify the generated nanorods. On the one hand, they regulate the morphology of the nanorods, and on the other hand, they promote the exposure of more defective surfaces of the nanorods, generating more oxygen vacancies, which is helpful for the migration of carriers and further improves the catalytic performance of the photocatalyst. When the prepared ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst is used to remove toluene, toluene, oxygen and water vapor in the air, under the action of this photocatalyst, are completely mineralized to generate CO2 and H2O.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses a tungsten mesh to oxidize elemental tungsten to form hybrid nanorods of tungsten dioxide and tungsten trioxide. By combining tungsten dioxide and tungsten trioxide, a redox electron pair is formed between the tetravalent and hexavalent tungsten, which promotes the photocatalytic reaction. At the same time, the addition of ammonium ions affects crystal growth, causing more defective surfaces of tungsten dioxide and tungsten trioxide nanorods to be exposed and generating more oxygen vacancies, which helps the migration of carriers and further improves the photocatalytic performance of the catalyst.

[0030] When the ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst provided by the present invention is used to remove toluene, under the action of the ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst, toluene reacts to generate CO2 and H2O. The experimental results show that the ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst prepared by the present invention can completely convert 50 ppm of toluene into CO2 and H2O in a short time, having excellent photocatalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0032] Figure 1 It is a physical diagram of the quartz reactor used in Example 2;

[0033] Figure 2 It is a TEM image of the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 magnified 500,000 times;

[0034] Figure 3 It is an SEM image of the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 magnified 100,000 times;

[0035] Figure 4 It is an XRD pattern of the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1;

[0036] Figure 5 It is a graph showing the change of toluene concentration and the change of carbon dioxide concentration when the tungsten oxide hybrid nanorod photocatalyst prepared in Example 2 is used for photocatalytic degradation of toluene with a concentration of 50 ppm;

[0037] Among them, the solid line is the graph of the change of toluene concentration, and the dotted line is the graph of the change of carbon dioxide concentration;

[0038] Figure 6 It is a graph showing the change of toluene concentration when the tungsten oxide hybrid nanorod photocatalyst prepared in Examples 2-4 is used for photocatalytic degradation of toluene with concentrations of 50, 40, and 20 ppm respectively;

[0039] Figure 7 The graph showing the change in the concentration of carbon dioxide when the tungsten oxide hybrid nanorod photocatalysts prepared in Examples 2-4 were used to photocatalytically degrade toluene at concentrations of 50, 40, and 20 ppm respectively;

[0040] Figure 8 The graph showing the change in the concentrations of toluene and carbon dioxide when the tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 6 was used to photocatalytically degrade toluene at a concentration of 50 ppm. Detailed Description of the Invention

[0041] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be construed as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0042] It should be understood that the terms used in the present invention are only for describing particular embodiments and are not intended to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0043] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0044] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0045] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0046] The present invention provides a tungsten oxide hybrid nanorod photocatalyst, which comprises a tungsten mesh and ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorods loaded on the surface of the tungsten mesh.

[0047] The present invention also provides a method for preparing a tungsten oxide hybrid nanorod photocatalyst, comprising the following steps:

[0048] Immerse the tungsten mesh in a mixed solution of concentrated nitric acid, hydrogen peroxide and water for an oxidation reaction;

[0049] After the oxidation reaction is completed, take out the tungsten mesh, add ammonium chloride to the remaining solution, stir and dissolve it, then add the taken-out tungsten mesh, carry out a hydrothermal reaction, and wash and dry the obtained product to obtain the tungsten oxide hybrid nanorod photocatalyst.

[0050] In some preferred embodiments of the present invention, the volume ratio of the total volume of concentrated nitric acid and hydrogen peroxide to the volume of water is (1-2):(40-60), preferably 1.8:50, wherein the volume ratio of concentrated nitric acid to hydrogen peroxide is (1-2):(1-3), preferably 1:1; the mass concentration of concentrated nitric acid is 68-70%; the mass concentration of hydrogen peroxide is 30-50%.

[0051] In some preferred embodiments of the present invention, the pore size of the tungsten mesh during the oxidation reaction is 80-100 mesh, preferably 100 mesh. In the present invention, when the pore size of the tungsten mesh is within the above range, it can not only prevent the small specific surface area caused by too low mesh number, but also prevent the small wire diameter when the mesh number is too large, which is easily corroded and damaged during the reaction, and thus is beneficial to the preparation of an ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst with excellent photocatalytic performance. The present invention has no special limitation on the source of the tungsten mesh, and commercially available products well-known to those skilled in the art can be used.

[0052] In some preferred embodiments of the present invention, before the oxidation reaction, the tungsten mesh is first cut, washed and dried.

[0053] Cutting means cutting the tungsten mesh to a suitable size so that it can be placed in the container for the hydrothermal reaction. The present invention has no special limitation on the size of the tungsten mesh after cutting, and it can be adjusted according to the size of the container for the hydrothermal reaction. In the following examples of the present invention, the capacity of the container for the hydrothermal reaction is 100 mL, and the size of the tungsten mesh after cutting is 5 cm×15 cm.

[0054] In the present invention, the washing reagent is preferably acetone, ethanol and deionized water. The present invention has no special limitation on the washing operation method, and the washing method well-known to those skilled in the art can be used. In the present invention, washing is to first place the cut tungsten mesh in a mixed solution of acetone and ethanol with a volume ratio of 1:4, carry out ultrasonic cleaning at a power of 75 W for 30 min, and then rinse with deionized water to remove impurities and grease on the surface of the tungsten mesh.

[0055] The drying method is drying with a hair dryer or cold air.

[0056] The present invention does not particularly limit the container for the hydrothermal reaction, and a hydrothermal reaction container well-known to those skilled in the art can be used. In the present invention, the container for the hydrothermal reaction is preferably a reaction kettle with a polytetrafluoroethylene lining.

[0057] In some preferred embodiments of the present invention, the hydrothermal reaction is carried out in a reaction kettle with a polytetrafluoroethylene lining; during the hydrothermal reaction, the amount of substance of ammonium chloride is 0.5 - 2 mmol, preferably 50 mL. The temperature of the hydrothermal reaction is 160 - 180 °C, and the reaction time is 12 - 24 h. Preferably, the temperature is 160 - 170 °C and the time is 20 - 24 h. More preferably, the temperature is 160 °C and the time is 24 h. In the present invention, when the temperature and time of the hydrothermal reaction are within the above ranges, it is more conducive to the progress of the hydrothermal reaction.

[0058] The present invention does not particularly limit the drying method, and a drying method well-known to those skilled in the art can be used. In some preferred embodiments of the present invention, after the hydrothermal reaction is completed, the reagent used for washing the product is water; the drying is preferably natural drying or drying in an oven, and more preferably natural drying. In the present invention, the natural drying can prevent the denaturation of the ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst.

[0059] The present invention also provides an application of a tungsten oxide hybrid nanorod photocatalyst in the photocatalytic degradation of toluene.

[0060] In some preferred embodiments of the present invention, the specific process of the application is as follows: Place the ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorod photocatalyst in a quartz reactor, then introduce toluene, and carry out a photocatalytic reaction to obtain CO2 and H2O. The present invention does not particularly limit the reactor, and a reactor well-known to those skilled in the art can be used. In the present invention, the reactor is preferably carried out in a self-made quartz reactor. The physical diagram of the quartz reactor is preferably as Figure 1 shown.

[0061] 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. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0062] The water used in the embodiments of the present invention is all deionized water.

[0063] The raw materials described in the embodiments of the present invention can all be obtained through commercial purchase.

[0064] Example 1

[0065] A preparation method of a tungsten oxide hybrid nanorod photocatalyst, comprising the following steps:

[0066] Select a commercial black tungsten mesh with a pore size of 100 mesh, cut it into pieces of 5 cm × 15 cm, then place it in a mixed solution of acetone and ethanol with a volume ratio of 1:4, and perform ultrasonic cleaning for 30 min at a power of 75 W. Finally, rinse it with deionized water and dry it with cold air for standby.

[0067] Immerse the above-mentioned washed and dried tungsten mesh in a mixed solution of concentrated nitric acid with a mass concentration of 70% and hydrogen peroxide with a mass concentration of 45% and deionized water for 0.5 h to carry out an oxidation reaction, wherein the total volume of concentrated nitric acid and hydrogen peroxide is 1.8 mL, the volume of deionized water is 50 mL, and the volume ratio of concentrated nitric acid to hydrogen peroxide is 1:1. After the oxidation reaction is completed, take out the tungsten mesh, add 1.3 mmol of ammonium chloride to the remaining solution, stir and dissolve it, then add the taken-out tungsten mesh, and put them together into a reaction kettle with a specification of 100 mL and a polytetrafluoroethylene lining for hydrothermal reaction, wherein the temperature of the hydrothermal reaction is 160 °C and the reaction time is 24 h. Finally, rinse the obtained product with deionized water and air-dry it naturally to obtain the tungsten oxide hybrid nanorod photocatalyst.

[0068] Scrape off the catalyst loaded on the tungsten mesh in the tungsten oxide hybrid nanorod photocatalyst prepared in this example, and test the catalyst by transmission electron microscopy and scanning electron microscopy to obtain a TEM image magnified 500,000 times (as Figure 2 shown) and an SEM image magnified 100,000 times (as Figure 3 shown).

[0069] From Figure 2 and Figure 3 it can be seen that in the tungsten oxide hybrid nanorod photocatalyst prepared in this example, the catalyst particles loaded on the tungsten mesh present a nanorod morphology, and the diameter of the nanorods is about 2 microns.

[0070] Then, perform X-ray diffraction analysis on the scraped catalyst to obtain an XRD pattern as Figure 4 shown.

[0071] From Figure 4 it can be seen that there are two substances, tungsten dioxide and tungsten trioxide, in the catalyst on the tungsten mesh scraped from the tungsten mesh, which proves the successful synthesis of tungsten dioxide-tungsten trioxide hybrid nanorods.

[0072] Example 2

[0073] An application of the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 in the photocatalytic degradation of toluene, and the specific process is as follows:

[0074] The tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 was used to degrade toluene. Using a 300-nm photocatalytic xenon lamp as the light source, a self-made quartz reactor (as Figure 1 shown) was used to conduct the experiment on the photocatalytic degradation of toluene. The initial concentration of toluene in the quartz reactor was 50 ppm, and the actual reaction area of the catalyst was 75 cm 2 (i.e., the area of the mesh). A laboratory gas chromatograph was used to measure the concentration changes of toluene and carbon dioxide during the reaction.

[0075] Samples were taken every 10 minutes, and the total reaction time was 1.5 h. The change curve of toluene concentration and the change curve of carbon dioxide concentration were obtained when the tungsten oxide hybrid nanorod photocatalyst photocatalytically degraded toluene with a concentration of 50 ppm, as Figure 5 shown.

[0076] In Figure 5 , the solid line is the change curve of toluene concentration, and the dashed line is the change curve of carbon dioxide concentration. It can be seen from Figure 5 that the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 of the present invention can completely mineralize toluene with a concentration of 50 ppm into carbon dioxide and water within 90 minutes.

[0077] Example 3

[0078] An application of the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 in the photocatalytic degradation of toluene, which is different from Example 2 in that: the initial concentration of toluene in the quartz reactor is 40 ppm;

[0079] The remaining steps are the same as those in Example 2.

[0080] Example 4

[0081] An application of the tungsten oxide hybrid nanorod photocatalyst prepared in Example 1 in the photocatalytic degradation of toluene, which is different from Example 2 in that: the initial concentration of toluene in the quartz reactor is 20 ppm;

[0082] The remaining steps are the same as those in Example 2.

[0083] Samples were taken every 10 minutes from the quartz reactors of Examples 2 - 4, and the reaction time for each example was 1.5 h. When the tungsten oxide hybrid nanorod photocatalyst photocatalytically degraded toluene with different concentrations, the change curve of toluene concentration (as Figure 6 shown) and the change curve of carbon dioxide concentration (as Figure 7 shown) were obtained.

[0084] From Figure 6 and Figure 7It can be seen that the tungsten oxide hybrid nanorod photocatalyst prepared by the present invention has good photocatalytic degradation effect on toluene with different concentrations.

[0085] Comparative Example 1

[0086] A preparation method of a tungsten oxide hybrid nanorod photocatalyst, which is different from Example 1 in that: the pore size of the tungsten mesh is 70 mesh;

[0087] The remaining steps are the same as those in Example 1.

[0088] The tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 1 was applied to the degradation process of toluene (the degradation conditions were the same as those in Example 2). The results showed that within 1.5 h, it could not completely convert 50 ppm of toluene into CO2 and H2O.

[0089] Comparative Example 2 [[ID=ID=17]]

[0090] A preparation method of a tungsten oxide hybrid nanorod photocatalyst, which is different from Example 1 in that: the pore size of the tungsten mesh is 105 mesh; [[ID=ID=20]]

[0091] The remaining steps are the same as those in Example 1.

[0092] The tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 2 was applied to the degradation process of toluene (the degradation conditions were the same as those in Example 2). The results showed that within 1.5 h, it could not completely convert 50 ppm of toluene into CO2 and H2O.

[0093] Comparative Example 3

[0094] A preparation method of a tungsten oxide hybrid nanorod photocatalyst, which is different from Example 1 in that: the mass concentration of concentrated nitric acid is 75%;

[0095] The remaining steps are the same as those in Example 1.

[0096] The catalyst loaded on the tungsten mesh in the tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 3 was scraped off, and the catalyst was tested by transmission electron microscopy and scanning electron microscopy. The results showed that in the tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 3, the nanoparticles loaded on the tungsten mesh had irregular nanorod morphologies.

[0097] The tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 3 was applied to the degradation process of toluene (the degradation conditions were the same as those in Example 2). The results showed that within 1.5 h, it could not completely convert 50 ppm of toluene into CO2 and H2O.

[0098] Comparative Example 4

[0099] A preparation method of tungsten oxide hybrid nanorod photocatalyst, which is different from Example 1 in that the hydrothermal reaction temperature is 190 °C;

[0100] The remaining steps are the same as those in Example 1.

[0101] The tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 4 was applied to the degradation process of toluene (the degradation conditions were the same as those in Example 2). The results showed that within 1.5 h, the toluene with a concentration of 50 ppm could not be completely converted into CO2 and H2O.

[0102] Comparative Example 5

[0103] A preparation method of tungsten oxide hybrid nanorod photocatalyst, which is different from Example 1 in that hydrogen peroxide is not added, and the oxidant is all concentrated nitric acid with a mass concentration of 70%;

[0104] The remaining steps are the same as those in Example 1.

[0105] The tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 5 was applied to the degradation process of toluene (the degradation conditions were the same as those in Example 2). The results showed that within 1.5 h, the toluene with a concentration of 50 ppm could not be completely converted into CO2 and H2O.

[0106] Comparative Example 6

[0107] A preparation method of tungsten oxide hybrid nanorod photocatalyst, which is different from Example 1 in that the total volume of concentrated nitric acid and hydrogen peroxide is 1 mL;

[0108] The remaining steps are the same as those in Example 1.

[0109] The tungsten oxide hybrid nanorod photocatalyst prepared in Comparative Example 6 was applied to the degradation process of toluene (the degradation conditions were the same as those in Example 2). The results showed (as Figure 8 shown) that within 1.5 h, the toluene with a concentration of 50 ppm could not be completely converted into CO2 and H2O.

[0110] The above is only the preferred specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A tungsten oxide hybrid nanorod photocatalyst, characterized in that, The photocatalyst includes a tungsten mesh and ammonium ion-modified tungsten dioxide-tungsten trioxide hybrid nanorods supported on the surface of the tungsten mesh; The preparation method of the photocatalyst includes the following steps: Immerse the tungsten mesh in a mixed solution of concentrated nitric acid, hydrogen peroxide and water for an oxidation reaction; After the oxidation reaction is completed, take out the tungsten mesh, add ammonium chloride to the remaining solution, stir and dissolve it, then add the taken-out tungsten mesh for a hydrothermal reaction, and wash and dry the obtained product to obtain the tungsten oxide hybrid nanorod photocatalyst; The aperture of the tungsten mesh is 80-100 mesh; During the oxidation reaction, the volume ratio of the total volume of the concentrated nitric acid and hydrogen peroxide to the volume of water is (1-2):(40-60), wherein the volume ratio of the concentrated nitric acid to the hydrogen peroxide is (1-2):(1-3); The mass concentration of the concentrated nitric acid is 68-70%; The mass concentration of the hydrogen peroxide is 30-50%; The temperature of the hydrothermal reaction is 160-180 °C.

2. A method for preparing a tungsten oxide hybrid nanorod photocatalyst as described in claim 1, characterized in that, Includes the following steps: Immerse the tungsten mesh in a mixed solution of concentrated nitric acid, hydrogen peroxide and water for an oxidation reaction; After the oxidation reaction is completed, take out the tungsten mesh, add ammonium chloride to the remaining solution, stir and dissolve it, then add the taken-out tungsten mesh for a hydrothermal reaction, and wash and dry the obtained product to obtain the tungsten oxide hybrid nanorod photocatalyst.

3. The preparation method of the tungsten oxide hybrid nanorod photocatalyst according to claim 2, characterized in that, During the oxidation reaction, the volume ratio of the total volume of the concentrated nitric acid and hydrogen peroxide to the volume of water is (1-2):(40-60), wherein the volume ratio of the concentrated nitric acid to the hydrogen peroxide is (1-2):(1-3); The mass concentration of the concentrated nitric acid is 68-70%; The mass concentration of the hydrogen peroxide is 30-50%.

4. The preparation method of the tungsten oxide hybrid nanorod photocatalyst according to claim 2, characterized in that, The amount of substance of ammonium chloride during the hydrothermal reaction is 0.5-2 mmol.

5. The preparation method of the tungsten oxide hybrid nanorod photocatalyst according to claim 2, characterized in that, The temperature of the hydrothermal reaction is 160-180 °C, and the reaction time is 12-24 h.

6. Application of the tungsten oxide hybrid nanorod photocatalyst as described in claim 1 in photocatalytic degradation of toluene.

7. The application according to claim 6, wherein The specific process of the application is: place the tungsten oxide hybrid nanorod photocatalyst as described in claim 1 in a reactor, then introduce toluene, and carry out a photocatalytic reaction to obtain CO2 and H2O.

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