Photocatalyst as well as preparation and application thereof
The photocatalyst is prepared by the modified polystyrene foam through Friedel-Crafts alkylation reaction, which solves the problem of waste foam utilization and achieves efficient production of hydrogen peroxide, with high yield and low cost, and is suitable for industrial applications.
Patent Information
- Application Number
- CN202510561964.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2025-08-05
AI Technical Summary
The prior art is difficult to efficiently use waste polystyrene foam to prepare photocatalysts for efficient production of hydrogen peroxide, and the traditional methods consume high energy and complex processes.
The polystyrene foam was reacted with a crosslinker and a Lewis acid catalyst under an inert atmosphere by Friedel-Crafts alkylation reaction to prepare a modified photocatalyst and hydrogen peroxide was produced under light conditions with oxygen and water as raw materials.
It has achieved efficient production of hydrogen peroxide, with a yield of 3.1 mmol/g/h, low cost and high catalyst stability, and has the prospect of large-scale industrial application.
Smart Images
Figure CN120424408A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a photocatalyst and a preparation method thereof, in particular to a photocatalyst prepared by modifying waste polystyrene foam and application thereof in photocatalytic preparation of hydrogen peroxide. Background Art
[0002] Waste polystyrene foam (PS) is a particularly difficult component of municipal solid waste to treat due to its non-degradable nature, and is known as white pollution. Waste PS materials contain hazardous substances such as benzene, toluene, and dichloromethane, which have a significant impact on the environment and human health. Random disposal or landfilling can seriously pollute soil and groundwater, damage the aquatic ecosystem, and threaten the safety of human drinking water. During the incineration process, waste foam produces a large amount of toxic gases, such as dioxins and other chlorine compounds. These gases are harmful to human health and damage the atmospheric environment. By modifying and processing waste polystyrene foam, it can be converted into coatings, adhesives, photocatalysts, etc. Modification is not only a necessary measure to reduce environmental pollution and improve resource utilization efficiency, but also an important way to promote sustainable development.
[0003] Hydrogen peroxide (H2O2) is a colorless, transparent liquid with strong oxidizing and bleaching properties. It is widely used in medical disinfection, industrial bleaching, oxygen production, wastewater treatment, and food preservation. Currently, there are many methods for producing H2O2, such as the anthraquinone method, direct hydrogen peroxide synthesis (DSHP), and electrolysis. However, most of these methods suffer from high energy consumption, high investment costs, and complex process flows. Photocatalytic production of hydrogen peroxide offers advantages such as green and sustainable synthesis, high selectivity, high quantum efficiency, and photochemical conversion efficiency. Therefore, the simple and efficient preparation of a functional material for hydrogen peroxide production through waste foam modification has become a pressing technical challenge. Summary of the Invention
[0004] Objectives of the invention: The objective of the present invention is to provide a catalyst for the efficient photocatalytic production of hydrogen peroxide in oxygen and water. Another objective is to provide a method for preparing the photocatalyst, thereby addressing the problem of how to prepare the photocatalyst. A third objective is to provide a use of the photocatalyst in the photocatalytic production of hydrogen peroxide, thereby addressing the problem of how to prepare the photocatalyst.
[0005] Technical solution: The photocatalyst of the present invention comprises a polymer represented by the following structural formula:
[0006]
[0007] wherein m and n are independently selected from 2-3000, R1 is selected from One of them.
[0008] Another aspect of the present invention discloses a method for preparing the above-mentioned photocatalyst, comprising the following steps:
[0009] The polystyrene foam and the cross-linking agent are dissolved in an organic solvent, a Lewis acid catalyst is added, and the reaction is carried out under an inert atmosphere to obtain a photocatalyst.
[0010] The present invention uses polystyrene foam as a parent unit and prepares the above-mentioned photocatalyst through Friedel-Crafts alkylation reaction. The introduction of aromatic groups will improve the conjugation of the material and tend to increase the planarity of the molecule, which is beneficial to the catalytic performance of this type of material.
[0011] Preferably, the cross-linking agent is at least one of biphenyl dichlorobenzyl, 1,4-bis(chloromethyl)benzene, and 1,4-dichlorobenzene.
[0012] Preferably, the Lewis acid catalyst is aluminum chloride or ferric chloride, and the organic solvent is at least one of toluene, dichloromethane, N,N-dimethylformamide, tetrahydrofuran, 1,2-dichloroethane, 1,4-dioxane, chloroform, and dimethyl sulfoxide.
[0013] Preferably, the molar ratio of the polystyrene foam to the cross-linking agent is 2:2-4.
[0014] Preferably, the reaction conditions under the inert atmosphere are 65-75° C. for 3-6 days under a nitrogen or helium atmosphere.
[0015] Preferably, after the reaction is completed under an inert atmosphere, the following product purification step is further included:
[0016] The reaction product is filtered to obtain a solid to obtain a crude product, the crude product is washed with methanol and a hydrochloric acid aqueous solution, and then the crude product is subjected to Soxhlet extraction with methanol for 2-3 days, and vacuum dried to obtain a photocatalyst.
[0017] The third aspect of the present invention discloses the use of the above-mentioned photocatalyst in the photocatalytic preparation of H2O2.
[0018] The method for photocatalytically preparing H2O2 using the above-mentioned photocatalyst comprises the following steps:
[0019] Under aerobic conditions, the photocatalyst is mixed with water and then continuously exposed to light to react and produce H2O2.
[0020] Preferably, the aerobic condition is an air environment and the light condition is 500-700 mW / cm 2 The photocatalyst is irradiated with high intensity, and the material-liquid ratio of the photocatalyst to water is 2-7 mg: 10-30 mL.
[0021] The photocatalyst and water can be mixed by ultrasonic dispersion method, with the power of ultrasonic dispersion being 2000-4500 Hz and the time being 5-10 minutes.
[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:
[0023] This invention fully recycles and modifies waste polystyrene foam to prepare a photocatalyst. The preparation method is simple and the photocatalyst yield is high. When used to produce H2O2, the photocatalyst can achieve efficient H2O2 production from oxygen and water by precisely controlling the catalyst ratio. The H2O2 yield can reach 3.1 mmol / g / h, resulting in low production costs and high catalyst stability, promising large-scale industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the solid ultraviolet absorption graph of the photocatalyst prepared by the present invention;
[0025] Figure 2 The impedance diagram of the photocatalyst prepared by the present invention;
[0026] Figure 3 The experimental results of hydrogen peroxide photocatalytic ability of photocatalysts prepared with different raw material ratios are shown;
[0027] Figure 4 The experimental results of the stability of the photocatalyst prepared in Example 2 are as follows;
[0028] Figure 5 The experimental results of the photocatalyst prepared in Example 2 for degrading hydrogen peroxide are shown. DETAILED DESCRIPTION
[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings.
[0030] Example 1: A photocatalyst having the following structure:
[0031]
[0032] The preparation method of the above-mentioned photocatalyst is as follows:
[0033] To a 500mL Shrek tube, add discarded polystyrene foam (2g, 14.9mmol), biphenyl dichloride (3.74g, 14.89mmol), and chloroform (150mL). After thorough dissolution and mixing, add 2.98g of aluminum chloride and react under a nitrogen atmosphere for 30 minutes. Heat to 70°C and react for 3 days with a plate monitor. After the reaction is complete, filter the solid to obtain the crude product, which is then washed with methanol and aqueous hydrochloric acid. Extract with methanol for 2-3 days to obtain PS-2 (4.28g), a pale yellow powder with a yield of 74%.
[0034] Example 2: Photocatalyst was prepared as follows:
[0035] To a 500mL Shrek tube, add discarded polystyrene foam (2g, 14.9mmol), biphenyl dichloride (5.6g, 22.3mmol), and chloroform (150mL). After thorough dissolution and mixing, add 2.98g of aluminum chloride and react under a nitrogen atmosphere for 30 minutes. Heat to 65°C and react for 3 days with a plate monitor. After the reaction is complete, filter the solid to obtain the crude product, which is then washed with methanol and aqueous hydrochloric acid. Extract with methanol for 2-3 days to obtain PS-3 (6.48g), a pale yellow powder with a yield of 85%.
[0036] Example 3: Photocatalyst was prepared as follows:
[0037] To a 500mL Shrek tube, add discarded polystyrene foam (2g, 14.9mmol), diphenylbenzyl chloride (7.48g, 29.8mmol), and dichloromethane (150mL). After thorough dissolution and mixing, add 2.98g of aluminum chloride and react under a nitrogen atmosphere for 30 minutes. Heat to 75°C and react for 3 days with a plate monitor. After the reaction is complete, filter the solid to obtain the crude product, which is then washed with methanol and aqueous hydrochloric acid. Extract with methanol for 2-3 days to obtain PS-4 (7.2g), a pale yellow powder with a yield of 75%.
[0038] Example 4: A photocatalyst, the structural formula of which is as follows:
[0039]
[0040] The photocatalyst was prepared as follows:
[0041] To a 500mL Shrek tube, add discarded polystyrene foam (2g, 14.9mmol), 1,4-bis(chloromethyl)benzene (29.8mmol), and tetrahydrofuran (150mL). Dissolve and mix thoroughly, then add 2.98g of ferric chloride. React under nitrogen for 30 minutes. Heat to 65°C and react for 6 days with a plate monitor. After the reaction, filter the solid to obtain the crude product, which is then washed with methanol and aqueous hydrochloric acid. Extract with methanol for 2-3 days to obtain PS-5, a pale yellow powder with a yield of 57%.
[0042] Example 5: A photocatalyst having the following structural formula:
[0043]
[0044] The photocatalyst was prepared as follows:
[0045] To a 500mL Shrek tube, add discarded polystyrene foam (2g, 14.9mmol), 1,4-dichlorobenzene (29.8mmol), and N,N-dimethylformamide (150mL). Dissolve and mix thoroughly, then add 2.98g of aluminum chloride. React under nitrogen for 30 minutes. Heat to 70°C and react for 5 days with a plate monitor. After the reaction, filter the solid to obtain the crude product, which is then washed with methanol and aqueous hydrochloric acid. Extract with methanol for 2-3 days to obtain PS-6, a pale yellow powder with a yield of 64%.
[0046] Example 6: Photocatalyst was prepared as follows:
[0047] To a 500mL Shrek tube, add discarded polystyrene foam (2g, 14.9mmol), 1,4-dichlorobenzene (22.3mmol), and 1,4-dioxane (150mL). Dissolve and mix thoroughly, then add 2.98g of aluminum chloride. React under nitrogen for 30 minutes. Heat to 70°C and react for 3 days with a plate monitor. After the reaction, filter the solid to obtain the crude product, which is then washed with methanol and aqueous hydrochloric acid. Extract with methanol for 2-3 days to obtain PS-7, a pale yellow powder with a yield of 62%.
[0048] The light absorption performance and impedance of the photocatalysts prepared in Examples 1-3 were tested. Figure 1 and 2 shown. Figure 1 The UV-visible absorption spectra of three different samples (PS-2, PS-3, and PS-4) are shown, among which PS-3 shows the highest absorbance in the wavelength range of 200-300nm, followed by PS-2, and PS-4 has the lowest absorbance. The high absorbance of these samples in the UV region indicates that they may have good photocatalytic activity, which helps promote the decomposition of hydrogen peroxide, thereby possibly increasing the yield of hydrogen peroxide. The electrochemical impedance spectroscopy (EIS) diagram shows the impedance characteristics of the three samples PS-2, PS-3, and PS-4, among which lower charge transfer resistance is generally associated with higher electrochemical activity, which may mean that in the process of electrochemical synthesis of hydrogen peroxide, samples with lower charge transfer resistance, such as PS-3, may exhibit higher catalytic efficiency and better hydrogen peroxide production performance.
[0049] Example 7: Photocatalytic hydrogen peroxide production test
[0050] The photocatalyst PS-3 (5 mg) prepared in Example 2 was added to pure water (20 mL), and ultrasonicated at 3500 Hz for 7 minutes to ensure uniform dispersion. The mixed solution was slowly poured into a 50 mL specific reactor and heated under air using a 300 W xenon lamp (600 mW / cm 2) for illumination. Every 10 minutes, 1.5 mL of the reaction solution was sampled for one hour. After filtering out catalyst particles using a 0.22 μm filter membrane, 1 mL of a 0.02 M potassium titanium oxalate solution was added. Finally, the absorbance of the solution at 400 nm was measured using a UV spectrophotometer, and the hydrogen peroxide concentration after one hour was calculated to be 2.43 mmol / L.
[0051] Example 8: The rest is the same as Example 7, except that:
[0052] PS-3 (2.5 mg) was added to pure water (20 mL) and ultrasonicated at 4500 Hz for 5 min with an illumination intensity of 500 mW / cm 2 .
[0053] The calculated concentration of hydrogen peroxide in 1 hour is 0.4mmol / L.
[0054] Example 9: The rest is the same as Example 7, except that:
[0055] PS-3 (10 mg) was added to seawater (20 mL) and ultrasonicated at 2000 Hz for 10 min with an illumination intensity of 700 mW / cm 2 The concentration of hydrogen peroxide in 1 hour was calculated to be 0.3 mmol / L.
[0056] Example 10: The rest is the same as Example 7, except that:
[0057] PS-3 (10 mg) was added to river water (20 mL). The hydrogen peroxide concentration was calculated to be 0.5 mmol / L after 1 h.
[0058] The photocatalyst was prepared according to the method in Example 2, and the molar ratio of waste polystyrene foam and biphenyl dichloride was changed as variables (2:2, 2:3, 2:4) to investigate the effect of the raw material ratio on the catalytic performance of the photocatalyst. The results are shown in FIG. Figure 3 As shown. Figure 3 It can be seen that when the molar ratio of waste polystyrene foam and biphenyl dichloride is 2:3, the photocatalyst prepared has the strongest catalytic ability, and the H2O2 yield can reach up to 3.1mmol / g / h.
[0059] The stability of the photocatalyst prepared in Example 2 was tested as follows:
[0060] The photocatalyst PS-3 (5 mg) prepared in Example 2 was added to pure water (20 mL), and ultrasonicated at 3500 Hz for 7 minutes to ensure uniform dispersion. The mixed solution was slowly poured into a 50 mL specific reactor and heated under air using a 300 W xenon lamp (600 mW / cm 2) for illumination, taking 1.5 mL of the reaction solution every 10 minutes for one hour, filtering out the catalyst particles with a 0.22 μm filter membrane, and then adding 1 mL of potassium titanium oxalate solution (0.02 M). Finally, the absorbance of the solution at 400 nm was measured and calculated using a UV spectrophotometer. The catalyst in the filter membrane was removed, washed and dried with ultrapure water and methanol, and the experiment was repeated four times. The results are shown in the figure below. Figure 4 As shown by Figure 4 The graph shows five consecutive runs (runs 1 through 5). The hydrogen peroxide production increases over time in each run until it reaches a plateau, indicating stable production. Each run lasts approximately 60 minutes, and the hydrogen peroxide production remains constant after each run, demonstrating the catalyst's stability and catalytic efficiency over multiple cycles.
[0061] The degradation effect of the photocatalyst prepared in Example 2 on hydrogen peroxide was tested as follows:
[0062] The photocatalyst PS-3 (5 mg) prepared in Example 2 was added to a 1 mmol / L hydrogen peroxide solution (20 mL). Ultrasonication was performed at 3500 Hz for 7 minutes to ensure uniform dispersion. The mixed solution was slowly sampled with 1.5 mL of the reaction solution every 10 minutes for one hour. The catalyst particles were filtered out with a 0.22 μm filter membrane, and then 1 mL of potassium titanium oxalate solution (0.02 M) was added. Finally, the absorbance of the solution at 400 nm was measured using an ultraviolet spectrophotometer and calculated. The results are shown in FIG. Figure 5 As shown by Figure 5 The degradation of hydrogen peroxide (H2O2) within 60 minutes of the experiment can be seen. The vertical axis shows the ratio of hydrogen peroxide concentration to initial concentration, Ct / C0. The results show that the concentration of hydrogen peroxide remains relatively stable throughout the experiment, and the ratio is maintained at around 1, indicating that hydrogen peroxide has not undergone significant degradation, showing good stability.
Claims
1. A photocatalyst, characterized in that Contains a polymer shown in the following structural formula: wherein m and n are independently selected from 2-3000, R1 is selected from One of them.
2. The method for preparing a photocatalyst according to claim 1, wherein: The steps include: The polystyrene foam and the cross-linking agent are dissolved in an organic solvent, a Lewis acid catalyst is added, and the reaction is carried out under an inert atmosphere to obtain a photocatalyst.
3. The method for preparing a photocatalyst according to claim 2, wherein: The cross-linking agent is at least one of biphenyl dichlorobenzyl, 1,4-bis(chloromethyl)benzene, and 1,4-dichlorobenzene.
4. The method for preparing a photocatalyst according to claim 2, wherein: The Lewis acid catalyst is aluminum chloride or ferric chloride, and the organic solvent is at least one of toluene, dichloromethane, N,N-dimethylformamide, tetrahydrofuran, 1,2-dichloroethane, 1,4-dioxane, chloroform, and dimethyl sulfoxide.
5. The method for preparing a photocatalyst according to claim 2, wherein: The molar ratio of the polystyrene foam to the cross-linking agent is 2:2-4.
6. The method for preparing a photocatalyst according to claim 2, wherein: The reaction conditions under the inert atmosphere are 65-75° C. under a nitrogen or helium atmosphere for 3-6 days.
7. The method for preparing a photocatalyst according to claim 2, wherein: After the reaction is completed under an inert atmosphere, the following product purification steps are also included: The reaction product is filtered to obtain a solid to obtain a crude product, the crude product is washed with methanol and a hydrochloric acid aqueous solution, and then the crude product is Soxhlet extracted with methanol for 2-3 days, and vacuum dried to obtain a photocatalyst.
8. Use of the photocatalyst according to claim 1 in photocatalytic production of H2O2.
9. The use according to claim 8, characterized in that The steps include: Under aerobic conditions, the photocatalyst is mixed with water and continuously irradiated with light to produce H2O2.
10. The use according to claim 8, characterized in that The aerobic condition is an air environment, and the light condition is 500-700mW / cm 2 The photocatalyst is irradiated with high intensity, and the material-liquid ratio of the photocatalyst to water is 2-7 mg: 10-30 mL.