Photocatalytic material as well as preparation method and application thereof

Abstract

The invention relates to a photocatalytic material and a preparation method and application thereof, and the preparation method comprises the following steps: (1) dispersing TiO2 powder into a mixed solution of a platinum precursor solution and a methanol solution, stirring and reacting under the irradiation of a xenon lamp, and then separating and drying to obtain a Pt / TiO2 product; (2) dripping turbid liquid prepared from the Pt / TiO2 product and water onto a quartz plate, drying, and performing ultraviolet radiation to obtain a Pt / TiO2-UV product; and (3) dispersing the Pt / TiO2-UV product into absolute ethyl alcohol, adding active carbon fibers for dipping treatment, taking out, drying, and calcining to obtain the photocatalytic material. The photocatalytic material prepared by the invention has stable and efficient catalytic efficiency when being used for treating VOCs-containing gas, and is especially suitable for efficient and stable treatment of high-humidity VOCs-containing waste gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalytic materials, and in particular relates to a photocatalytic material for organic waste gas, a preparation method and an application thereof. Background Art

[0002] Volatile organic compounds (VOCs) are one of the main pollutants in the atmosphere, with characteristics such as wide sources, high volatility, and easy diffusion. At present, the treatment and control technologies for VOC-containing gases are divided into two categories: destruction and recovery. Destruction methods include catalytic oxidation, biodegradation, and photocatalysis, while recovery methods include adsorption, absorption, condensation, and membrane treatment technologies. Although these methods have their own advantages, most of them have high energy consumption, harsh operating conditions, or produce large amounts of waste that require further treatment. Photocatalytic oxidation, as a mild and clean advanced oxidation technology, can use solar energy to degrade VOCs into CO2. It has the advantages of high treatment efficiency and low operating costs, and is suitable for the removal of most VOCs.

[0003] CN117258785A discloses a Eu-Ag-TiO2 composite photocatalyst and its preparation method, comprising: 1. mixing tetrabutyl titanate with anhydrous ethanol to obtain solution A; 2. dissolving europium nitrate hexahydrate and silver nitrate in anhydrous ethanol to obtain solution B; 3. adding solution A to solution B and adding anhydrous methanol to obtain a mixed solution; 4. irradiating the mixed solution with ultraviolet light; 5. adding water to the irradiated mixed solution to obtain a gel; 6. drying the gel to obtain a dry product; and 7. grinding and calcining the dry product. This invention combines photochemical reduction with the sol-gel method. By introducing the rare earth metal Eu and the precious metal Ag, the band gap of the TiO2 photocatalyst is narrowed, its adsorption of visible light is enhanced, and its adsorption of organic pollutants and visible light catalytic activity are improved, making it suitable for the degradation and purification of antibiotic contaminants in water. However, during the preparation process, TiO2 particles tend to agglomerate when precipitating to obtain the sol, which not only leads to an uneven pore size distribution of the catalyst but also reduces catalytic performance.

[0004] In order to improve the activity of photocatalysts and increase the efficiency of natural visible light utilization, precious metals such as Pt can be deposited on the surface of semiconductors such as TiO2. Pt is generally loaded on the surface of TiO2 by the impregnation precipitation method, the sol method, etc. Since Kraeutler et al. successfully obtained well-dispersed Pt nanoparticles on TiO2 by irradiating TiO2 powder and a suspension of Pt precursor together, the photodeposition method has attracted much attention. The photodeposition method can be completed under mild reaction conditions and is an important method for preparing Pt / TiO2. However, due to the high work function of the carrier, the raw material (Pt 2+ and PtO x ) easily migrates to the surface of the TiO2 support, thereby reducing the active species Pt0 The content of TiO2 weakens the activity of precious metals in photocatalysts. Studies have found that TiO2 can generate a large number of oxygen vacancies under ultraviolet light. Oxygen vacancies serve as centers for the growth and nucleation of Pt particles, promoting the formation of Pt clusters, thereby strengthening the adsorption and oxidation capacity of individual active sites and improving the activity of photocatalysts.

[0005] The literature "Effect of UV-Promoted Electron Migration on CO Catalytic Oxidation Performance of Pt / TiO2 Catalyst (Liu Xinli et al., Journal of Central South University, Vol. 54, No. 8, August 2023) uses TiO2 powder and platinum tetrachloride as raw materials, and a liquid phase impregnation method is used to prepare the Pt / TiO2 precursor. The sample is irradiated with an ultraviolet lamp, and then dried and sintered to obtain the Pt / TiO2 photocatalyst. The results show that ultraviolet irradiation leads to an increase in the size of Pt particles and the active species Pt 0 The increase in the Pt / TiO2 concentration enhances the adsorption and oxidation of CO at low temperatures and reduces the occurrence of side reactions and the formation of intermediates. The product produced using the liquid-phase impregnation method in this study is limited by the particle size of the material and the low dispersion of the metal elements within the crystals. Furthermore, the low specific surface area of ​​the Pt / TiO2 material itself hinders the capture of small organic molecules during the photocatalytic process of gaseous pollutants.

[0006] Furthermore, humidity is a key factor affecting the treatment of VOC-containing gases. Water often occupies the majority of adsorption sites in the treatment system, reducing the catalytic efficiency of the target pollutants. This is particularly true when operating for extended periods at relative humidity levels above 50%. Therefore, suitable photocatalytic materials are crucial for addressing this technical issue in high-humidity VOC-containing gases.

[0007] CN110180520A discloses a method for preparing a recyclable mesoporous carbon @ TiO2 / carbon fiber (CFs) photocatalytic material, comprising the following steps: (1) dissolving ethylene glycol in acetone to obtain solution A; (2) adding mesoporous carbon spheres to solution A and ultrasonically dispersing them to obtain suspension B; (3) adding tetrabutyl titanate to suspension B and ultrasonically dispersing them to obtain suspension C; (4) transferring suspension C to a high-pressure reactor and immersing carbon fibers in suspension C. The reactants undergo a solvothermal reaction under magnetic stirring to produce solvothermal product D; (5) ultrasonically washing and drying solvothermal product D to obtain a mesoporous carbon @ TiO2 / carbon fiber photocatalytic material. This invention prepares photocatalytic materials through solvothermal reaction, solving the problem of separating and recovering powdered photocatalysts during actual use. However, the photocatalytic materials prepared by this method do not consider the impact of high humidity environments on the application effect, and the effect will be significantly attenuated after long-term use. Summary of the Invention

[0008] In response to the shortcomings of the prior art, the present invention provides a photocatalytic material, a preparation method, and applications thereof. The photocatalytic material prepared by the present invention has stable and efficient catalytic efficiency when treating VOCs-containing gases, and is particularly suitable for the efficient and stable treatment of high-humidity VOCs-containing waste gas.

[0009] A first aspect of the present invention provides a method for preparing a photocatalytic material, comprising the following steps:

[0010] (1) dispersing TiO2 powder into a mixture of a platinum precursor solution and a methanol solution, stirring the mixture under irradiation with a xenon lamp, and then separating and drying the mixture to obtain a Pt / TiO2 product;

[0011] (2) dropping a suspension of the Pt / TiO2 product and water onto a quartz plate, drying it, and then irradiating it with ultraviolet light to obtain a Pt / TiO2-UV product;

[0012] (3) The Pt / TiO2-UV product is dispersed in anhydrous ethanol, and activated carbon fiber is added for impregnation treatment. After being taken out, it is dried and calcined to obtain a photocatalytic material.

[0013] In the present invention, the platinum precursor in step (1) is a soluble platinum salt, preferably one or more of potassium chloroplatinate, platinum nitrate, platinum tetrachloride, etc., and the concentration of the platinum precursor solution is 0.05-1.0 mol / L.

[0014] In the present invention, the concentration of the methanol solution in step (1) is 0.5-2.0 mol / L.

[0015] In the present invention, the volume ratio of the platinum precursor solution and the methanol solution in step (1) is 1:1-1:8.

[0016] In the present invention, the ratio of the TiO2 powder to the mixed solution in step (1) is 1 mg: 0.5-3 mL, preferably 1 mg: 1-2 mL. The particle size of the TiO2 powder is 0.1-0.3 microns.

[0017] In the present invention, the power of the xenon lamp in step (1) is 200-500W, the speed of the stirring reaction is 200-500rpm, and the reaction time is 1-6h.

[0018] In the present invention, the separation in step (1) is carried out by centrifugation, filtration, etc. The drying temperature is 80-200° C. and the drying time is 4-16 hours.

[0019] In the present invention, the ratio of the Pt / TiO2 product to water in step (2) is 1 mg: 1-10 mL, preferably 1 mg: 1-5 mL. The water can be any one of deionized water, pure water, distilled water, etc.

[0020] In the present invention, the drying temperature of the suspension in step (2) is 60-120° C., and the drying time is 4-16 hours.

[0021] In the present invention, the ultraviolet irradiation in step (2) adopts a low-pressure mercury lamp, and the irradiation time is 0.2-5.0h, preferably 0.5-2.0h.

[0022] In the present invention, the ratio of the Pt / TiO2-UV product in step (3) to anhydrous ethanol is 1 mg:0.5-1 mL.

[0023] In the present invention, the activated carbon fiber described in step (3) is at least one of polypropylene-based carbon fiber, viscose-based carbon fiber, asphalt-based carbon fiber, etc., preferably asphalt-based carbon fiber.

[0024] In the present invention, the impregnation time of adding activated carbon fibers in step (3) is 2-16 hours, preferably 4-10 hours.

[0025] In the present invention, after taking out in step (3), drying is carried out, the drying temperature is 60-100° C., and the drying time is 3-10 hours.

[0026] In the present invention, the calcination temperature in step (3) is 300-850°C, preferably 500-800°C, and the calcination time is 4-20 hours, preferably 8-18 hours. More preferably, the calcination is carried out under an inert atmosphere, using any one of N2, Ar, He, etc.

[0027] In the present invention, it is further preferred that the activated carbon fiber is first immersed in a silane reagent for treatment, and then immersed in a mixture of Pt / TiO2-UV and anhydrous ethanol for treatment. The silane is at least one of n-octyltrimethoxysilane, heptafluorodecyltrimethoxysilane, trifluorooctyltrimethoxy, trichlorooctadecylsilane, etc., preferably heptafluorodecyltrimethoxysilane. The concentration of the silane reagent is 0.1-2.0 mol / L, preferably 0.25-1.0 mol / L. The preparation method of the silane reagent is preferably: dissolving ethylenediamine hydrochloride in a Tris-HCl solution to prepare a 3-5 g / L buffer solution, then dissolving the silane in the buffer solution to prepare a silane reagent with a concentration of 0.1-2.0 mol / L.

[0028] A second aspect of the present invention provides a photocatalytic material prepared using the above-described method. The prepared photocatalytic material is prepared by photodepositing Pt onto a TiO2 surface, which is then immobilized on an activated carbon fiber substrate after UV irradiation. The material exhibits a stable catalytic interface and good catalytic activity.

[0029] The third aspect of the present invention provides an application of the above-mentioned photocatalytic material of the present invention, which is used for photocatalytic oxidation treatment of VOCs-containing gases, and is particularly suitable for photocatalytic oxidation treatment of high-humidity VOCs-containing gases, and has an efficient and stable treatment effect.

[0030] In the application of the present invention, the conditions for the photocatalytic oxidation are: the wavelength of light is 420-750nm and the power is 400-600W.

[0031] In the application of the present invention, the high humidity refers to the humidity of the VOCs-containing gas being not less than 30% at normal temperature and pressure, generally 50%-80%.

[0032] In the application of the present invention, the VOCs refer to organic substances with a boiling point less than or equal to 250°C at normal pressure and a vapor pressure greater than 0.5 kPa at 25°C, such as at least one of small molecular organic substances such as toluene, acetone, and formaldehyde.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The inventors of this application found in their research that when the precious metal Pt is loaded on the surface of TiO2, due to the high work function of TiO2, the electrons of the Pt particles easily migrate to the surface of TiO2, resulting in the active Pt o The reduction of the content limits the improvement of the performance of the Pt / TiO2 photocatalyst. To this end, the inventors of this application first prepared modified Pt / TiO2, dried it, and then solidified it on an activated carbon fiber substrate after ultraviolet irradiation. This can promote the electron transition on the TiO2 carrier, transfer the photogenerated electrons to the surface of the Pt site, and increase the surface active species Pt o The content makes the prepared photocatalytic material have a stable catalytic interface and good catalytic activity.

[0035] (2) When existing photocatalytic materials are used to treat high-humidity VOCs-containing gases, although they can work well in the first use, the effect will be significantly reduced after long-term use. The present invention immobilizes Pt / TiO2-UV on activated carbon fibers, and TiO2 and activated carbon fibers are bonded through C-Ti bonds. The Ti in TiO2 +4 After the activated carbon fibers are reduced to Ti +2 It not only expands the response wavelength range of the photocatalytic material, enhances the visible light sensing effect and interface charge transfer of the material, and improves the VOCs catalytic effect; it also improves the stability of the material in long-term use in high-humidity environments.

[0036] (3) Immobilizing the Pt / TiO2-UV prepared by the present invention onto the activated carbon fiber treated with a silane reagent can further avoid the adverse effects of high humidity on the photocatalytic material, and achieve better long-term use effects. DETAILED DESCRIPTION

[0037] The technical solution of the present invention and its effects are further illustrated below with reference to specific examples. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples.

[0038] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, were purchased from conventional biochemical reagent stores.

[0039] Example 1

[0040] (1) 100 mL of a 0.07 mol / L potassium chloroplatinate solution was mixed with 400 mL of a 1.3 mol / L methanol solution. 0.5 g of 0.3 μm TiO2 powder was added to the mixed solution. The mixture was then stirred at 500 rpm under a 300 W xenon lamp for 3 h. After filtration, the mixture was dried at 150°C for 5 h to obtain a Pt / TiO2 product.

[0041] (2) 0.1 g of Pt / TiO2 product was mixed with 200 mL of deionized water to prepare a suspension, which was dropped onto a quartz plate and dried at 95°C for 10 h. The suspension was then irradiated with ultraviolet light under a low-pressure mercury lamp at a wavelength of 253 nm for 2 h to obtain a Pt / TiO2-UV product.

[0042] (3) 20 mg of the Pt / TiO2-UV product was dispersed in 15 mL of anhydrous ethanol to prepare a mixture. The pitch-based carbon fibers were then immersed in the mixture for 7.5 h. The mixture was then dried in a 75°C oven for 8.5 h and calcined in a tube furnace at 650°C in a nitrogen atmosphere for 12 h to obtain a photocatalytic material.

[0043] Example 2

[0044] (1) 200 mL of a 0.06 mol / L potassium chloroplatinate solution was mixed with 200 mL of a 0.55 mol / L methanol solution. 0.2 g of 0.1 μm TiO2 powder was added to the mixed solution. The mixture was then stirred at 220 rpm under a 200 W xenon lamp for 2 h. After filtration, the mixture was dried at 85°C for 6 h to obtain a Pt / TiO2 product.

[0045] (2) 0.1 g of the Pt / TiO2 product was mixed with 100 mL of deionized water to prepare a suspension, which was dropped onto a quartz plate and dried at 65°C for 16 h. The suspension was then irradiated with ultraviolet light under a low-pressure mercury lamp at a wavelength of 253 nm for 0.5 h to obtain the Pt / TiO2-UV product.

[0046] (3) 20 mg of the Pt / TiO2-UV product was dispersed in 20 mL of anhydrous ethanol to prepare a mixture. The pitch-based carbon fibers were then immersed in the mixture for 2.5 h. The mixture was then dried in a 60°C oven for 10 h and calcined in a tube furnace at 500°C in a nitrogen atmosphere for 6 h to obtain a photocatalytic material.

[0047] Example 3

[0048] (1) 200 mL of a 1.0 mol / L potassium chloroplatinate solution was mixed with 700 mL of a 2.0 mol / L methanol solution. 0.45 g of 0.3 μm TiO2 powder was added to the mixed solution. The mixture was then stirred at 450 rpm under a 500 W xenon lamp for 4 h. After filtration, the mixture was dried at 195°C for 5 h to obtain a Pt / TiO2 product.

[0049] (2) 0.3 g of the Pt / TiO2 product was mixed with 500 mL of deionized water to prepare a suspension, which was dropped onto a quartz plate and dried at 115°C for 5 h. The suspension was then irradiated with ultraviolet light under a low-pressure mercury lamp at a wavelength of 253 nm for 4.5 h to obtain a Pt / TiO2-UV product.

[0050] (3) 20 mg of the Pt / TiO2-UV product was dispersed in 10 mL of anhydrous ethanol to prepare a mixture. The pitch-based carbon fibers were then immersed in the mixture for 12 h. The mixture was then dried in a 100°C oven for 9 h and calcined in a tube furnace at 350°C in a nitrogen atmosphere for 20 h to obtain a photocatalytic material.

[0051] Example 4

[0052] The same as Example 1, except that the platinum precursor is platinum nitrate, and the photocatalytic material is finally prepared.

[0053] Example 5

[0054] The same as Example 1, except that the platinum precursor is platinum tetrachloride, and the photocatalytic material is finally prepared.

[0055] Example 6

[0056] The same as Example 1, except that the activated carbon fibers are polypropylene-based carbon fibers, and the photocatalytic material is finally prepared.

[0057] Example 7

[0058] The same as Example 1, except that the activated carbon fibers are viscose-based carbon fibers, and the photocatalytic material is finally prepared.

[0059] Example 8

[0060] The same as Example 1, except that the activated carbon fibers are first immersed in a silane reagent and then immersed in a mixture of Pt / TiO2-UV nanoparticles and anhydrous ethanol to obtain a photocatalytic material.

[0061] The specific method for preparing the silane reagent is as follows: dissolving ethylenediamine hydrochloride in a Tris-HCl solution to prepare a 4 g / L buffer solution, and then dissolving heptadecafluorodecyltrimethoxysilane in the buffer solution to prepare a silane reagent with a concentration of 0.25 mol / L.

[0062] Example 9

[0063] The same method as Example 8, except that in the preparation of the silane reagent, n-octyltrimethoxysilane was used, and the concentration was 1.5 mol / L. Finally, a photocatalytic material was obtained.

[0064] Comparative Example 1

[0065] The same as Example 1, except that methanol solution was not used in step (1). Finally, a photocatalytic material was obtained.

[0066] Comparative Example 2

[0067] The same as Example 1, except that step (1) does not use xenon lamp irradiation. Finally, a photocatalytic material is obtained.

[0068] Comparative Example 3

[0069] The same as Example 1, except that step (2) does not use ultraviolet irradiation. Finally, a photocatalytic material is obtained.

[0070] Comparative Example 4

[0071] The same as Example 1, except that no activated carbon fiber was added for impregnation in step (3). Finally, a photocatalytic material was obtained.

[0072] Comparative Example 5

[0073] The same as Example 1, except that deionized water is used instead of anhydrous ethanol in step (3), and finally a photocatalytic material is obtained.

[0074] Test Example 1

[0075] The photocatalytic materials prepared in the examples of the present invention and the comparative examples were used to treat VOCs-containing gas: the VOCs in the gas was toluene with a concentration of 1000 mg / m 3 , relative humidity is 70%.

[0076] 0.4 g of catalyst was placed in a double-layer quartz cold trap photocatalytic purification device with a volume of 50 mL. After high-humidity VOCs gas was introduced, the sample was irradiated with a xenon lamp (CEL-HXF300) with a wavelength of 420 nm and a power of 500 W for 1.5 h, and the CO2 in the system was detected using a gas chromatograph (GC-9790plus, Fuli). The CO2 generation rate is shown in Table 1.

[0077] Table 1 Experimental results of different embodiments and comparative examples

[0078]

[0079]

[0080] Test Example 2

[0081] The photocatalytic materials prepared in the examples of the present invention and the comparative examples were used to treat VOCs-containing gas: the VOCs in the gas was acetone with a concentration of 1000 mg / m 3 , relative humidity is 60%.

[0082] 0.4 g of catalyst was placed in a double-layer quartz cold trap photocatalytic purification device with a volume of 50 mL. After high-humidity VOCs gas was introduced, the sample was irradiated with a xenon lamp (CEL-HXF300) with a wavelength of 600 nm and a power of 500 W for 1.5 h. The CO2 in the system was detected using a gas chromatograph (GC-9790plus, Fuli). The CO2 generation rate is shown in Table 1.

[0083] Table 1 Experimental results of different embodiments and comparative examples

[0084]

[0085]

[0086] As shown in Tables 1 and 2, the photocatalytic material prepared by the present invention can maintain good catalytic effect and long-term stability when used to treat high-humidity VOCs-containing gases. However, if any of the technical features of the present invention are missing, the effect will be significantly reduced after long-term use.

Claims

1. A method for preparing a photocatalytic material, characterized in that The following steps are involved: (1) Dispersing TiO2 powder into a mixture of a platinum precursor solution and a methanol solution, stirring the mixture under irradiation with a xenon lamp, and then separating and drying the mixture to obtain a Pt / TiO2 product; (2) Dropping the suspension of Pt / TiO2 product and water onto a quartz plate, drying it and then irradiating it with ultraviolet light to obtain a Pt / TiO2-UV product; (3) The Pt / TiO2-UV product was dispersed in anhydrous ethanol, and activated carbon fiber was added for impregnation treatment. After being taken out, it was dried and calcined to obtain a photocatalytic material.

2. The preparation method according to claim 1, wherein: The platinum precursor in step (1) is a soluble platinum salt, preferably one or more of potassium chloroplatinate, platinum nitrate, and platinum tetrachloride, and the concentration of the platinum precursor solution is 0.05-1.0 mol / L.

3. The preparation method according to claim 1, wherein: The concentration of the methanol solution in step (1) is 0.5-2.0 mol / L.

4. The preparation method according to claim 1, 2 or 3, characterized in that: The volume ratio of the platinum precursor solution and the methanol solution in step (1) is 1:1-1:

8.

5. The preparation method according to claim 1, wherein: The ratio of TiO2 powder to the mixed solution in step (1) is 1 mg:0.5-3 mL, preferably 1 mg:1-2 mL.

6. The preparation method according to claim 1 or 5, characterized in that: The particle size of the TiO2 powder described in step (1) is 0.1-0.3 microns.

7. The preparation method according to claim 1, wherein: The power of the xenon lamp in step (1) is 200-500W, the speed of the stirring reaction is 200-500 rpm, and the reaction time is 1-6 hours; the drying temperature is 80-200°C, and the drying time is 4-16 hours.

8. The preparation method according to claim 1, wherein: The ratio of the Pt / TiO2 product to water in step (2) is 1 mg:1-10 mL, preferably 1 mg:1-5 mL.

9. The preparation method according to claim 1 or 9, characterized in that: The water in step (2) is any one of deionized water, pure water, and distilled water.

10. The preparation method according to claim 1, characterized in that: The drying temperature of the suspension in step (2) is 60-120°C, and the drying time is 4-16 hours.

11. The preparation method according to claim 1, characterized in that: The ultraviolet irradiation in step (2) uses a low-pressure mercury lamp, and the irradiation time is 0.2-5.0 hours, preferably 0.5-2.0 hours.

12. The preparation method according to claim 1, characterized in that: The ratio of the Pt / TiO2-UV product to anhydrous ethanol in step (3) is 1 mg:0.5-1 mL.

13. The preparation method according to claim 1 or 13, characterized in that: The activated carbon fiber described in step (3) is at least one of polypropylene-based carbon fiber, viscose-based carbon fiber, and asphalt-based carbon fiber, preferably asphalt-based carbon fiber.

14. The preparation method according to claim 1, characterized in that: The impregnation time for adding activated carbon fibers in step (3) is 2-16 hours, preferably 4-10 hours.

15. The preparation method according to claim 1, characterized in that: After taking out in step (3), the product is dried at a temperature of 60-100°C and a drying time of 3-10 hours; the calcination temperature is 300-850°C, preferably 500-800°C; and the calcination time is 4-20 hours, preferably 8-18 hours.

16. The preparation method according to claim 1 or 15, characterized in that: The calcination in step (3) is carried out under an inert atmosphere, and the gas used is any one of N2, Ar, and He.

17. The preparation method according to claim 1, characterized in that: Step (3) The activated carbon fiber is first immersed in a silane reagent for treatment, and then immersed in a mixture of Pt / TiO2-UV and anhydrous ethanol for treatment; The concentration of the silane reagent is 0.1-2.0 mol / L, preferably 0.25-1.0 mol / L.

18. The preparation method according to claim 19, characterized in that: The silane is at least one of n-octyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, trifluorooctyltrimethoxy, and trichlorooctadecylsilane, preferably heptadecafluorodecyltrimethoxysilane.

19. The preparation method according to claim 1 or 19, characterized in that: The preparation method of the silane reagent is as follows: dissolving ethylenediamine hydrochloride in a Tris-HCl solution to prepare a 3-5 g / L buffer solution, and then dissolving silane in the buffer solution to prepare a silane reagent with a concentration of 0.1-2.0 mol / L.

20. A photocatalytic material, characterized in that It is prepared by the method according to any one of claims 1 to 19.

21. A use of the photocatalytic material according to claim 20, characterized in that Used for photocatalytic oxidation treatment of VOCs-containing gases, especially suitable for photocatalytic oxidation treatment of VOCs-containing gases with high humidity.

22. The use according to claim 21, characterized in that: The conditions for the photocatalytic oxidation are: the wavelength of light is 420-750nm and the power is 400-600W.

23. The use according to claim 21, characterized in that: The high humidity refers to the humidity of VOCs-containing gas being not less than 30% at normal temperature and pressure, generally 50%-80%.

24. The use according to claim 21, characterized in that: The VOCs are organic compounds with a boiling point less than or equal to 250°C at normal pressure and a vapor pressure greater than 0.5 kPa at 25°C, preferably at least one of toluene, acetone, and formaldehyde small molecule organic compounds.

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