Preparation method and application of Ag / AgCl photocatalyst
Patent Information
- Application Number
- CN202410576757.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-10
- Publication Date
- 2026-10-09
AI Technical Summary
[0005]本发明解决了现有技术使用的TiO2基半导体光催化剂对太阳光的利用率不高且量子效率较低，光催化降解乙烯的能力较弱的问题
[0020]本发明制备的Ag/AgCl光催化材料不仅能够拓宽光吸收范围，提高了对太阳光的利用率，而且由于TiO2在可见光下没有响应，与传统的TiO2光催化材料相比，本发明制备的光催化材料在可见光下，照射5～6h对乙烯的降解率为99％，光催化性能显著提升。
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Figure CN122875259A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a method for preparing and applying an Ag / AgCl photocatalyst. Background Technology
[0002] Ethylene is a volatile organic compound (VOC) whose sources include natural release (e.g., from fruits and vegetables), fossil fuel combustion, vehicle exhaust emissions, plastics, and smog). As a plant hormone, ethylene acts as a ripening agent in fruits and vegetables, inducing ripening and adding aroma and flavor. However, during transportation and storage, ethylene can promote over-ripening and even spoilage. Ethylene concentrations of 0.1-1 mg / kg promote fruit ripening; concentrations exceeding 1 mg / kg accelerate spoilage. Therefore, eliminating ethylene gas in the transportation and storage environment of fruits and vegetables is of significant economic value in extending their shelf life. Furthermore, photochemical pollution resulting from the transformation of ethylene in the air causes severe air pollution, and eliminating ethylene gas in the environment is also crucial for the healthy and sustainable development of human society.
[0003] Currently, the main methods for eliminating ethylene in the environment include physical adsorption, biological filtration, strong oxidant oxidation, plasma method, thermocatalytic oxidation, or photocatalytic oxidation. Physical adsorption methods mainly use activated carbon and molecular sieves to adsorb ethylene. Although these adsorbents have strong adsorption capacity, the adsorbed gas is prone to desorption when the temperature rises. Biofiltration is similar to adsorption methods. Although simple and convenient, it has limited gas processing capacity and is expensive. Strong oxidant oxidation methods include potassium permanganate oxidation, ozone oxidation, and ultraviolet light oxidation decomposition. Although these oxidants have strong oxidizing power and low cost, they need to be replaced frequently, which can easily cause secondary pollution. Plasma methods involve the gas being broken down under the action of an external electric field to generate high-energy electrons, ions, free radicals, and other active particles that react rapidly with ethylene molecules in the air. Although this method can efficiently and thoroughly oxidize ethylene molecules without causing secondary pollution, the entire process consumes a lot of energy and is costly. Thermocatalytic oxidation has high catalytic efficiency and can handle large flow rates of gas, but the heat treatment temperature is generally around 250°C, which consumes a lot of energy and the precious metals loaded on the catalyst are expensive, which is not conducive to large-scale promotion and application. Photocatalytic oxidation utilizes sunlight to catalytically oxidize organic gaseous pollutants on a photocatalyst. This method features simple equipment and processes, is green, energy-saving, and environmentally friendly, and has broad market application prospects.
[0004] Research reports on the photocatalytic degradation of ethylene mainly focus on TiO2-based semiconductor photocatalysts. However, TiO2 has a wide band gap, absorbing only about 5% of the energy in the ultraviolet light spectrum, resulting in low utilization of sunlight and low quantum efficiency, thus limiting its ability to photocatalytically degrade ethylene. Therefore, there is an urgent need to develop a photocatalyst capable of degrading ethylene under visible light. Summary of the Invention
[0005] This invention solves the problems of low utilization rate of sunlight and low quantum efficiency of TiO2-based semiconductor photocatalysts used in the prior art, resulting in weak photocatalytic degradation of ethylene.
[0006] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0007] The ionic liquid is dissolved in water, then silver nitrate solution is added and mixed thoroughly to obtain a mixture.
[0008] The mixture was reacted at 120–160 °C for 1–8 h, cooled, purified, and dried to obtain AgCl.
[0009] Silver ions on the surface of AgCl are reduced to elemental silver, and Ag / AgCl is obtained by purification.
[0010] Preferably, the ionic liquid is 1-octyl-3-methylimidazolium chloride.
[0011] Preferably, the concentration of the silver nitrate solution is 0.1M.
[0012] Preferably, the ratio of 1-octyl-3-methylimidazolium chloride to water and silver nitrate solution is 1.2 mmol: 70 mL: 10 mL.
[0013] Preferably, in preparing Ag / AgCl, the AgCl is irradiated with light to form Ag / AgCl.
[0014] Preferably, the AgCl is irradiated with a 300W xenon lamp for 5 to 20 minutes.
[0015] Preferably, the purification method specifically involves: filtration, washing the precipitate with deionized water and anhydrous ethanol, and drying it under vacuum at 50-60°C to constant weight to obtain AgCl.
[0016] The second objective of this invention is to protect the Ag / AgCl photocatalyst prepared by the aforementioned method.
[0017] A third objective of this invention is to protect the application of the Ag / AgCl photocatalyst in the catalytic degradation of organic pollutants under visible light.
[0018] Preferably, the organic pollutant is ethylene.
[0019] Compared with the prior art, the beneficial effects of the present invention are:
[0020] The Ag / AgCl photocatalytic material prepared by this invention not only broadens the light absorption range and improves the utilization rate of sunlight, but also, since TiO2 does not respond under visible light, compared with traditional TiO2 photocatalytic materials, the photocatalytic material prepared by this invention achieves a 99% degradation rate of ethylene under visible light irradiation for 5-6 hours, demonstrating a significant improvement in photocatalytic performance.
[0021] The preparation method of the Ag / AgCl photocatalytic material of the present invention is simple and easy to operate, with a wide light response range and significantly enhanced absorption of visible light. It also exhibits excellent photocatalytic performance. Experimental studies have shown that the Ag / AgCl photocatalytic material has good performance in degrading ethylene under visible light, which is a significant improvement compared with traditional TiO2 photocatalytic materials.
[0022] This invention uses ionic liquids as raw materials to adjust the morphology, size, structure, and properties of the material, which is an advantage that distinguishes it from other inorganic chloride salts. Attached Figure Description
[0023] Figure 1 X-ray diffraction patterns of AgCl and Ag / AgCl prepared in this invention;
[0024] Figure 2 Here is a SEM image of the AgCl prepared in this invention;
[0025] Figure 3 The light absorption diagrams are of AgCl, Ag / AgCl and TiO2(P25) prepared in this invention;
[0026] Figure 4 This is a comparison diagram of Ag / AgCl prepared in this invention and commercial TiO2 (P25) used for photocatalytic degradation of ethylene. Detailed Implementation
[0027] The technical solutions of this invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0028] Unless otherwise specified, the methods described in the various embodiments of this invention are conventional methods. Unless otherwise specified, the materials and reagents used are commercially available.
[0029] Example 1
[0030] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0031] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0032] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0033] (3) Transfer the mixed solution obtained in step (2) above to the reaction vessel and place it in an oven at 120°C for 1 hour.
[0034] (4) After the reaction is complete, the mixture is naturally cooled to room temperature, filtered, and the precipitate is washed three times with deionized water and three times with anhydrous ethanol. Then, it is placed in a vacuum drying oven at 50°C and dried to constant weight to obtain AgCl.
[0035] Then, the silver ions on the AgCl surface were reduced to elemental silver during the degradation process using a photoreduction method to obtain the Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: the prepared AgCl was irradiated with a 300W xenon lamp for 10 minutes to obtain the Ag / AgCl photocatalyst with only the surface reduced to elemental silver.
[0036] Example 2
[0037] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0038] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0039] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0040] (3) Transfer the mixed solution obtained in step (2) above to the reaction vessel and place it in an oven at 130°C for 3 hours.
[0041] (4) After the reaction is complete, the mixture is naturally cooled to room temperature, filtered, and the precipitate is washed three times with deionized water and three times with anhydrous ethanol. Then, it is placed in a vacuum drying oven at 53°C and dried to constant weight to obtain AgCl.
[0042] Then, the silver ions on the AgCl surface are reduced to elemental silver during the degradation process using a photoreduction method, yielding an Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: The prepared AgCl is irradiated with a 300W xenon lamp for 10 minutes, resulting in an Ag / AgCl photocatalyst where only the surface is reduced to elemental silver.
[0043] Example 3
[0044] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0045] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0046] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0047] (3) Transfer the mixed solution obtained in step (2) above to a high-pressure reactor and place it in an oven at 140°C for 4 hours.
[0048] (4) After the reaction is complete, the precipitate is naturally cooled to room temperature, filtered, washed three times with deionized water and three times with anhydrous ethanol, and then placed in a vacuum drying oven at 56°C to constant weight to obtain AgCl.
[0049] Then, the silver ions on the AgCl surface were reduced to elemental silver during the degradation process using a photoreduction method to obtain the Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: the prepared AgCl was irradiated with a 300W xenon lamp for 10 minutes to obtain the Ag / AgCl photocatalyst with only the surface reduced to elemental silver.
[0050] Example 4
[0051] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0052] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0053] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0054] (3) Transfer the mixed solution obtained in step (2) above to the reaction vessel and place it in an oven at 150°C for 6 hours.
[0055] (4) After the reaction is complete, the mixture is naturally cooled to room temperature. The precipitate is filtered, washed three times with deionized water and three times with anhydrous ethanol, and then placed in a vacuum drying oven at 59°C to constant weight to obtain AgCl.
[0056] Then, the silver ions on the AgCl surface were reduced to elemental silver during the degradation process using a photoreduction method to obtain the Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: the prepared AgCl was irradiated with a 300W xenon lamp for 10 minutes to obtain the Ag / AgCl photocatalyst with only the surface reduced to elemental silver.
[0057] Example 5
[0058] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0059] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0060] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0061] (3) Transfer the mixed solution obtained in step (2) above to a high-pressure reactor and place it in an oven at 160°C for 8 hours.
[0062] (4) After the reaction is complete, the precipitate is cooled to room temperature naturally. The precipitate is filtered, washed three times with deionized water and three times with anhydrous ethanol, and then placed in a vacuum drying oven at 60°C to constant weight to obtain AgCl.
[0063] Then, the silver ions on the AgCl surface were reduced to elemental silver during the degradation process using a photoreduction method to obtain the Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: the prepared AgCl was irradiated with a 300W xenon lamp for 10 minutes to obtain the Ag / AgCl photocatalyst with only the surface reduced to elemental silver.
[0064] Comparative Example 1
[0065] TiO2 (P25) was purchased from Degussa GmbH, Germany.
[0066] Comparative Example 2 (below reaction temperature)
[0067] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0068] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0069] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0070] (3) Transfer the mixed solution obtained in step (2) above to a high-pressure reactor and place it in an oven at 100°C for 4 hours.
[0071] (4) After the reaction is complete, the mixture is naturally cooled to room temperature, filtered, and the precipitate is washed three times with deionized water and three times with anhydrous ethanol. Then, it is placed in a vacuum drying oven at 60°C and dried to constant weight to obtain AgCl.
[0072] Then, the silver ions on the AgCl surface were reduced to elemental silver during the degradation process using a photoreduction method to obtain the Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: the prepared AgCl was irradiated with a 300W xenon lamp for 10 minutes to obtain the Ag / AgCl photocatalyst with only the surface reduced to elemental silver.
[0073] Comparative Example 3 (above reaction temperature)
[0074] A method for preparing an Ag / AgCl photocatalyst, specifically including the following steps:
[0075] (1) Add 1.2 mmol of 1-octyl-3-methylimidazolium chloride to 70 mL of deionized water and stir until completely dissolved.
[0076] (2) Add 10 mL of 0.1 M silver nitrate solution dropwise to the solution in step (1) above, and stir continuously for 2 h to obtain a mixed solution.
[0077] (3) Transfer the mixed solution obtained in step (2) above to a high-pressure reactor and place it in an oven at 200°C for 4 hours.
[0078] (4) After the reaction is complete, the mixture is naturally cooled to room temperature, filtered, and the precipitate is washed three times with deionized water and three times with anhydrous ethanol. Then, it is placed in a vacuum drying oven at 60°C and dried to constant weight to obtain AgCl.
[0079] Then, the silver ions on the AgCl surface were reduced to elemental silver during the degradation process using a photoreduction method to obtain the Ag / AgCl photocatalyst. The specific steps of the photoreduction method are as follows: the prepared AgCl was irradiated with a 300W xenon lamp for 10 minutes to obtain the Ag / AgCl photocatalyst with only the surface reduced to elemental silver.
[0080] The Ag / AgCl photocatalyst particles prepared in Comparative Examples 2 and 3 were too small. Within a certain range, smaller catalyst particles result in a greater number of surface reactive centers, leading to a faster reaction rate. However, when the particles are too small, the increased surface area hinders substance diffusion, thus reducing the reaction rate. Therefore, a reasonable design of catalyst particle size helps improve catalytic reaction efficiency and selectivity. Only within the temperature range set in this invention, i.e., when the mixture is between 120 and 160°C, can a catalyst with a suitable particle size be obtained.
[0081] The catalytic performance of the Ag / AgCl photocatalysts prepared in Examples 1 and 3-5 of this invention is basically the same as that of the Ag / AgCl photocatalyst prepared in Example 2. The following tests are conducted using the Ag / AgCl photocatalyst prepared in Example 2 as an example.
[0082] The X-ray diffraction patterns of AgCl prepared in Example 2 before and after light irradiation are as follows: Figure 1 As shown, by Figure 1 It can be seen that the diffraction peaks of the synthesized AgCl are consistent with those of the JCPDS no.31-1238 standard card. The Ag / AgCl obtained after light reduction clearly shows the diffraction peaks of elemental silver (JCPDS no.65-2871).
[0083] SEM image of AgCl prepared in Example 2 is shown below. Figure 2 As shown, by Figure 2 It can be seen that the synthesized AgCl has a granular morphology.
[0084] The UV-Vis diffuse reflectance absorption spectra of AgCl and Ag / AgCl prepared in Example 2 are as follows: Figure 3 As shown, by Figure 3 It is evident that, compared to AgCl, Ag / AgCl exhibits significantly enhanced absorption in visible light, which is attributed to the surface plasmon resonance effect of silver particles on the AgCl surface.
[0085] To compare with traditional TiO2, commercial TiO2 (P25) and Ag / AgCl were compared in terms of their performance in degrading ethylene.
[0086] Finally, TiO2 and the Ag / AgCl prepared above were used in the photocatalytic degradation of ethylene gas experiment.
[0087] The specific implementation method is as follows: First, 0.5g of Ag / AgCl photocatalyst is uniformly dispersed in a 450mL closed quartz glass reactor. This reactor is connected to circulating cooling water to eliminate the influence of temperature changes on degradation performance. Then, 2mL of ethylene gas is injected into the quartz reactor, and the mixture is magnetically stirred in the dark for 2 hours to allow the ethylene gas to reach adsorption equilibrium on the catalyst surface. Next, the photocatalytic degradation of ethylene is tested using a 300W xenon lamp equipped with an ultraviolet cutoff filter, providing light with wavelengths greater than 420nm, which is irradiated through the top of the quartz reactor. A 30μL sample is manually taken every hour and analyzed using a Shimadzu gas chromatograph.
[0088] First, 0.5 g of TiO2 was uniformly dispersed in a 450 mL closed quartz glass reactor, which was connected to circulating cooling water to eliminate the influence of temperature changes on degradation performance. Then, 2 mL of ethylene gas was injected into the quartz reactor, and the mixture was magnetically stirred in the dark for 2 hours to allow the ethylene gas to reach adsorption equilibrium on the catalyst surface. Next, a photocatalytic degradation test of ethylene was conducted using a 300 W xenon lamp equipped with an ultraviolet cutoff filter, providing light with wavelengths greater than 420 nm, which was irradiated through the top of the quartz reactor. A 30 μL sample was manually taken every hour and analyzed using a Shimadzu gas chromatograph.
[0089] The degradation curve of ethylene by the Ag / AgCl prepared above under visible light is shown in the figure below. Figure 4 As shown, by Figure 4 It is evident that TiO2 hardly degrades ethylene under visible light, indicating that titanium dioxide does not respond to visible light. The Ag / AgCl photocatalyst prepared in this invention has a degradation rate of 99% for ethylene after irradiation with visible light for 5-6 hours, and its performance in degrading ethylene is far superior to that of TiO2.
[0090] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0091] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for preparing an Ag / AgCl photocatalyst, characterized in that, Specifically, the following steps are included: The ionic liquid is dissolved in water, then silver nitrate solution is added and mixed thoroughly to obtain a mixture. The mixture was reacted at 120–160 °C for 1–8 h, cooled, purified, and dried to obtain AgCl. Silver ions on the surface of AgCl are reduced to elemental silver, and Ag / AgCl is obtained by purification.
2. The method for preparing an Ag / AgCl photocatalyst according to claim 1, characterized in that, The ionic liquid is 1-octyl-3-methylimidazolium chloride.
3. The method for preparing an Ag / AgCl photocatalyst according to claim 2, characterized in that, The concentration of the silver nitrate solution is 0.1M.
4. The method for preparing an Ag / AgCl photocatalyst according to claim 3, characterized in that, The ratio of 1-octyl-3-methylimidazolium chloride to water and silver nitrate solution is 1.2 mmol: 70 mL: 10 mL.
5. The method for preparing an Ag / AgCl photocatalyst according to claim 1, characterized in that, In the preparation of Ag / AgCl, the AgCl is irradiated with light to form Ag / AgCl.
6. The method for preparing an Ag / AgCl photocatalyst according to claim 5, characterized in that, The AgCl was irradiated with a 300W xenon lamp for 5–20 minutes.
7. The method for preparing an Ag / AgCl photocatalyst according to claim 1, characterized in that, The purification method is as follows: after filtration, the precipitate is washed with deionized water and anhydrous ethanol, and then dried under vacuum at 50-60℃ to constant weight to obtain AgCl.
8. An Ag / AgCl photocatalyst prepared by the method described in any one of claims 1 to 7.
9. The application of the Ag / AgCl photocatalyst of claim 8 in the catalytic degradation of organic pollutants under visible light.
10. The application according to claim 9, characterized in that, The organic pollutant is ethylene.