Conjugated polymer photocatalysts, methods of making and using the same

Abstract

The application discloses preparation and application of a conjugated polymer photocatalyst, and particularly relates to the technical field of polymer, and the specific steps comprise the following steps: S1, melamine and trimesic acid are respectively dissolved in dimethyl sulfoxide to obtain corresponding clear melamine solution A and trimesic acid solution B; S2, the B solution obtained in the step S1 is poured into the A solution, and stirring is uniformly carried out to make the melamine and the trimesic acid polymerize. Then, deionized water is added, stirring is carried out until white precipitates are generated, centrifugal washing and drying are carried out; S3, the white precipitates are calcined, and a nanorod-shaped donor-acceptor type conjugated polymer photocatalyst is obtained. The application has the advantages of simple process and low cost, and the obtained product has good photocatalytic in-situ preparation H2O2 performance under simulated sunlight irradiation, and has wide application prospects in the fields of environmental remediation, medical disinfection and sterilization, corrosion prevention and deodorization.

Description

Technical Field

[0001] This invention relates to the field of polymer technology, specifically to nanorod-shaped donor-acceptor type conjugated polymer photocatalysts, their preparation methods, and applications. Background Technology

[0002] The rapid development of human society has also led to severe environmental pollution, seriously hindering sustainable development. Traditional environmental remediation processes often utilize strong oxidants such as sodium hypochlorite, potassium permanganate, and ozone. These strong oxidants are also used for disinfection in the medical field. While strong oxidants like sodium hypochlorite, potassium permanganate, and ozone are effective at removing pollutants and disinfecting, they can cause certain toxic side effects on the environment and human health. In contrast, hydrogen peroxide (H2O2) not only has excellent pollutant removal and disinfection effects, but its decomposition products (oxygen and water) do not harm the environment. Furthermore, H2O2 is inexpensive and safe to store and transport. Therefore, the development of a technology for the efficient production of H2O2 has attracted widespread attention from researchers.

[0003] Currently, the most common process for synthesizing H2O2 is the anthraquinone process. This method has a complex synthesis route, produces many toxic byproducts, and is costly. Directly synthesizing H2O2 from H2 and O2 via electrocatalysis carries the risk of explosion and requires precious metal catalysts, resulting in high costs and energy consumption. In contrast, photocatalysis technology can directly utilize sunlight to excite semiconductors to generate photoelectrons, thereby reducing molecular oxygen to produce H2O2. This reaction is mild and produces no secondary pollution, thus it is considered an ideal method for synthesizing H2O2.

[0004] As a new type of photocatalyst, organic conjugated polymer semiconductors have attracted widespread attention from researchers due to their advantages such as strong designability of chemical structures, ease of functionalization, and tunable valence bands. Theoretically, high-performance organic conjugated polymers should possess good light absorption properties, rapid and efficient charge transfer and separation, and good stability. To achieve these goals, the construction of donor-acceptor type conjugated polymers has sparked researchers' interest. The most commonly used strategy for synthesizing donor-acceptor type conjugated polymers is the Suzuki-Miyaura reaction; however, this reaction is time-consuming, requires the noble metal Pd catalysis, the monomers used have special functional groups, the monomers are expensive, and Pd remains in the polymer. Other types of organic polymerization reactions also typically require metal catalysis and have long reaction times. These drawbacks greatly inhibit the synthesis of donor-acceptor type conjugated polymer photocatalysts. Furthermore, to date, there are few reports on the photocatalytic preparation of H2O2 using donor-acceptor type organic conjugated polymer semiconductors. Summary of the Invention

[0005] To address the shortcomings and deficiencies in existing technologies, the present invention aims to provide a method for preparing nanorod-shaped donor-acceptor type conjugated polymer photocatalysts and their applications. The nanorod-shaped donor-acceptor type conjugated polymer photocatalysts prepared by the method of the present invention exhibit excellent photocatalytic production of H2O2 under simulated sunlight irradiation, and have broad application prospects in environmental remediation, medical disinfection and sterilization, and anti-corrosion and deodorization, thereby solving the problems mentioned in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a conjugated polymer photocatalyst, comprising the following steps: S1, dissolving melamine and trimesic acid in dimethyl sulfoxide respectively to obtain melamine solution A and trimesic acid solution B;

[0007] S2. Pour the B solution obtained in step S1 into the A solution, stir evenly to allow melamine and trimesic acid to polymerize, then add deionized water, stir until a white precipitate is formed, centrifuge, wash and dry.

[0008] S3. Calcination of the white precipitate yields the nanorod-shaped donor-acceptor type conjugated polymer photocatalyst.

[0009] Furthermore, in step S1, the molar ratio of melamine to trimesic acid is (2-8):(2-8), and the volume of dimethyl sulfoxide used to dissolve both melamine and trimesic acid is 20 mL to 40 mL.

[0010] Furthermore, in step S1, the molar ratio of melamine to trimellitic acid is 2:2, and the volume of dimethyl sulfoxide used to dissolve both melamine and trimellitic acid is 20 mL.

[0011] Furthermore, in step S1, the molar ratio of melamine to trimellitic acid is 8:8, and the volume of dimethyl sulfoxide used to dissolve both melamine and trimellitic acid is 20 mL.

[0012] Furthermore, in step S1, the molar ratio of melamine to trimellitic acid is 5:5, and the volume of dimethyl sulfoxide used to dissolve both melamine and trimellitic acid is 20 mL.

[0013] Furthermore, in step S2, when pouring solution B into solution A and stirring, the stirring temperature is 60℃~120℃ and the stirring time is 0.5h~3h.

[0014] Furthermore, in step S2, when solution B is poured into solution A and stirred, the stirring temperature is 60°C and the stirring time is 0.5 h.

[0015] Furthermore, in step S2, when solution B is poured into solution A and stirred, the stirring temperature is 60°C and the stirring time is 3 hours.

[0016] Furthermore, in step S2, when solution B is poured into solution A and stirred, the stirring temperature is 80°C and the stirring time is 0.5 h.

[0017] Furthermore, in step S2, when solution B is poured into solution A and stirred, the stirring temperature is 80°C and the stirring time is 3 hours.

[0018] Furthermore, in step S2, when solution B is poured into solution A and stirred, the stirring temperature is 120°C and the stirring time is 0.5 h.

[0019] Furthermore, in step S2, when solution B is poured into solution A and stirred, the stirring temperature is 120°C and the stirring time is 3 hours.

[0020] Furthermore, in step S2, the stirring time for obtaining the white precipitate at room temperature is 0.5h to 3h.

[0021] Furthermore, in step S2, the stirring time for obtaining the white precipitate at room temperature is 0.5 h.

[0022] Furthermore, in step S2, the stirring time for obtaining the white precipitate at room temperature is 3 hours.

[0023] Furthermore, in step S3, the atmosphere for calcining the conjugated polymer precursor is an air or nitrogen atmosphere.

[0024] Furthermore, in step S3, the atmosphere for calcining the conjugated polymer precursor is an air atmosphere.

[0025] Furthermore, in step S3, the atmosphere for calcining the conjugated polymer precursor is a nitrogen atmosphere.

[0026] Furthermore, in step S3, the heating rate of calcining the conjugated polymer precursor is 2°C·min. -1 ~10℃·min -1 The calcination time is 1 hour to 4 hours.

[0027] Furthermore, in step S3, the heating rate of calcining the conjugated polymer precursor is 2°C·min. -1 The calcination time is 1 hour.

[0028] Furthermore, in step S3, the heating rate of calcining the conjugated polymer precursor is 10 °C·min. -1 The calcination time is 2 hours.

[0029] Furthermore, in step S3, the heating rate of calcining the conjugated polymer precursor is 2°C·min. -1 The calcination time is 4 hours.

[0030] Furthermore, in step S3, the heating rate of calcining the conjugated polymer precursor is 10 °C·min. -1 The calcination time is 4 hours.

[0031] Furthermore, the characteristic is that in step S3, the temperature for calcining the conjugated polymer precursor is 300℃~500℃.

[0032] Furthermore, the characteristic is that in step S3, the temperature at which the conjugated polymer precursor is calcined is 300°C.

[0033] Furthermore, the characteristic is that in step S3, the temperature at which the conjugated polymer precursor is calcined is 350°C.

[0034] Furthermore, the characteristic is that in step S3, the temperature at which the conjugated polymer precursor is calcined is 400°C.

[0035] Furthermore, the characteristic is that in step S3, the temperature at which the conjugated polymer precursor is calcined is 450°C.

[0036] Furthermore, the characteristic is that in step S3, the temperature at which the conjugated polymer precursor is calcined is 500°C.

[0037] This invention discloses a method for preparing conjugated polymer photocatalysts using any of the above-mentioned methods.

[0038] This invention also provides the application of conjugated polymer photocatalysts in the preparation of H2O2.

[0039] The specific testing process for the photocatalytic H2O2 preparation performance is as follows: A flat-bottomed three-necked flask was used as the reactor for the photocatalytic H2O2 preparation experiment. A 300-watt xenon lamp (Zhongjiao Jinyuan) equipped with an AM1.5G filter was used as the simulated sunlight source for the experiment (the light source was aimed at the light-transmitting surface of the reactor and irradiated into the reactor from right to left). The specific process is as follows: First, 20 mg of photocatalyst was weighed and dispersed in 50 mL of ethanol aqueous solution (V... 乙醇 V 水A homogeneous dispersion was formed in a mixture of 1:9. Oxygen was then introduced into the three-necked flask for 30 minutes. Next, the dispersion was irradiated with a xenon lamp. During irradiation, 2 mL of the reaction solution was taken every 15 minutes and filtered through a 0.45 μm filter to obtain a clear and transparent solution. 1 mL of the clear and transparent solution was taken, and then 1 mL of 0.1 M potassium hydrogen phthalate and 1 mL of 0.4 M potassium iodide solution were added. The mixture was shaken and allowed to react for 30 minutes. Finally, the absorbance of the reaction solution was measured at 350 nm in a quartz cuvette. The yield of H2O2 produced by photocatalysis was quantified based on the measured absorbance and the H2O2 standard curve.

[0040] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0041] (1) This method is simple, easy to operate, short in time and low in energy consumption, and therefore has a better prospect for practical engineering applications.

[0042] (2) The nanorod-shaped donor-acceptor conjugated polymer catalyst prepared by this method exhibits excellent photocatalytic performance for the preparation of H2O2. It has broad application prospects in environmental remediation, medical disinfection and sterilization, anti-corrosion and deodorization, and is expected to provide new technical support for industrial production of H2O2. Attached Figure Description

[0043] Figure 1 The XRD patterns of each sample in the specific implementation method are shown below.

[0044] Figure 2 The image shows a scanning electron microscope (SEM) image of the MT350 in a specific implementation.

[0045] Figure 3 The images show the UV-Vis diffuse reflectance spectra of each sample in the specific implementation method.

[0046] Figure 4 The performance of each sample in the photocatalytic preparation of H2O2 in the specific implementation method is shown. Detailed Implementation

[0047] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] This invention provides a method for testing the performance of photocatalytic H2O2 preparation. The specific testing process for the performance of photocatalytic H2O2 preparation is as follows:

[0050] A flat-bottomed three-necked flask was used as the reactor for the photocatalytic preparation of H2O2. A 300-watt xenon lamp (Zhongjiao Jinyuan) equipped with an AM1.5G filter was used as the simulated sunlight source (the light source was aimed at the light-transmitting surface of the reactor and irradiated into the reactor from right to left). The specific procedure is as follows: First, 20 mg of photocatalyst was weighed and dispersed in 50 mL of ethanol aqueous solution (V... 乙醇 V 水 A homogeneous dispersion was formed in a mixture of 1:9. Oxygen was then introduced into the three-necked flask for 30 minutes. Next, the dispersion was irradiated with a xenon lamp. During irradiation, 2 mL of the reaction solution was taken every 15 minutes and filtered through a 0.45 μm filter to obtain a clear and transparent solution. 1 mL of the clear and transparent solution was taken, and then 1 mL of 0.1 M potassium hydrogen phthalate and 1 mL of 0.4 M potassium iodide solution were added. The mixture was shaken and allowed to react for 30 minutes. Finally, the absorbance of the reaction solution was measured at 350 nm in a quartz cuvette. The yield of H2O2 produced by photocatalysis was quantified based on the measured absorbance and the H2O2 standard curve.

[0051] A method for preparing a nanorod-shaped donor-acceptor conjugated polymer with high photocatalytic activity for the preparation of H2O2:

[0052] 8 mmol of melamine was dispersed in 20 mL of dimethyl sulfoxide to form a clear, transparent solution A. 8 mmol of trimesic acid was then dispersed in the same solution to form a clear, transparent solution B. Solution B was added to solution A at 80 °C and stirred for 3 h. After the mixture cooled to room temperature, 200 mL of deionized water was added, and stirring continued for 3 h to obtain a white precipitate. The precipitate was washed by centrifugation with anhydrous ethanol and deionized water, and then dried at 80 °C to obtain the conjugated polymer precursor (MT). MT was calcined in air at 350 °C for 2 h at a heating rate of 10 °C / min. -1 This yields nanorod-shaped donor-acceptor conjugated polymers. For example... Figure 4 As shown, the sample was named MT350, and its photocatalytic production of H2O2 yield was 451.3 μmol·h⁻¹. -1 ·g -1 .

[0053] Example 2

[0054] A method for preparing a nanorod-shaped donor-acceptor conjugated polymer with high photocatalytic activity for the preparation of H2O2:

[0055] To investigate the effect of calcination temperature on the photocatalytic activity of nanorod-shaped donor-acceptor conjugated polymers in preparing H2O2, the catalyst preparation method was exactly the same as in Example 1, except that the calcination temperature was changed to 300℃. Figure 4 As shown, the sample, named MT300, had a photocatalytic yield of 27.6 μmol·h⁻¹ for the production of H₂O₂. -1 ·g -1 .

[0056] Example 3

[0057] A method for preparing a nanorod-shaped donor-acceptor conjugated polymer with high photocatalytic activity for the preparation of H2O2:

[0058] To investigate the effect of calcination temperature on the photocatalytic activity of nanorod-shaped donor-acceptor conjugated polymers in preparing H2O2, the catalyst preparation method was exactly the same as in Example 1, except that the calcination temperature was changed to 400℃. Figure 4 As shown, the sample, named MT400, had a photocatalytic yield of 330.4 μmol·h⁻¹ for the production of H₂O₂. -1 ·g -1 .

[0059] Example 4

[0060] A method for preparing a nanorod-shaped donor-acceptor conjugated polymer with high photocatalytic activity for the preparation of H2O2:

[0061] To investigate the effect of calcination temperature on the photocatalytic activity of nanorod-shaped donor-acceptor conjugated polymers in preparing H2O2, the catalyst preparation method was exactly the same as in Example 1, except that the calcination temperature was changed to 450℃. Figure 4 As shown, the sample, named MT450, had a photocatalytic yield of 282.1 μmol·h⁻¹ for the production of H₂O₂. -1 ·g -1 .

[0062] Comparative Example 1

[0063] A method for preparing a nanorod-shaped donor-acceptor conjugated polymer with high photocatalytic activity for the preparation of H2O2:

[0064] To investigate the effect of calcination temperature on the photocatalytic activity of nanorod-shaped donor-acceptor conjugated polymers in the preparation of H2O2, the applicant conducted a control experiment. For example... Figure 4 As shown, the photocatalytic activity of H2O2 preparation was tested using MT in Example 1, and the yield of H2O2 preparation was 0.

[0065] from Figure 1X-ray diffraction (XRD) characterization revealed that the precursor MT exhibited numerous sharp characteristic diffraction peaks in the 2θ range of 5–45°. When the precursor MT was calcined at 300°C for 2 hours, the XRD pattern of sample MT300 was essentially the same as that of MT. When the precursor MT was calcined at 350°C for 2 hours, the XRD pattern of sample MT350 was completely different from that of MT. This is because the polymerization reaction between melamine and trimesic acid essentially did not occur during calcination at 300°C. The characteristic diffraction peaks of sample MT350 were mainly located around 2θ 26°, which is due to the π-π stacking of the polymer. When the temperature was further increased to 400°C and 450°C, the XRD patterns of samples MT400 and MT450 were the same as those of MT350, indicating that the minimum temperature for the polymerization reaction was 350°C.

[0066] Figure 2 This is a scanning electron microscope image of the MT350 sample. From... Figure 2 As can be seen, the MT350 sample exhibits a nanorod morphology. The lateral dimensions of the nanorods are approximately between 500 nm and 1 μm, and the longitudinal dimensions are between 4 μm and 8 μm, with the nanorods interlacing with each other.

[0067] Figure 3 The UV-Vis diffuse reflectance spectra for all samples are shown. Figure 3 It can be seen that sample MT has two absorption band edges in the ultraviolet region. This is because melamine and trimesic acid are formed through hydrogen bonding polymerization, resulting in the formation of two absorption band edges. When the temperature rises to 300℃, the absorption band edge of sample MT300 redshifts to about 380nm compared to MT. This is because melamine and trimesic acid undergo slight polymerization during low-temperature calcination (300℃), and the two are linked by covalent bonds. XRD results also confirm this. When the calcination temperature rises to 350℃, the polymerization reaction is complete, and melamine and trimesic acid form a conjugated polymer, causing the absorption band edge of the sample to redshift to about 500nm. When the calcination temperature rises to 400℃ and 450℃, the absorption band edge of the sample further redshifts to 600nm to 700nm. This is because the increased temperature causes partial carbonization of the sample, and the conjugated structure of the sample is partially destroyed.

[0068] Figure 4 The photocatalytic preparation of H2O2 activity was determined for all samples. Figure 4It can be seen that sample MT did not exhibit photocatalytic activity because melamine and trimesic acid did not undergo a polymerization reaction, and the conjugated polymer was not formed. Sample MT300 showed slight photocatalytic activity because melamine and trimesic acid underwent slight polymerization. Sample MT350 showed the best photocatalytic activity for the preparation of H2O2 because the polymerization reaction was complete at this temperature, forming the conjugated polymer. When the temperature continued to rise to 400℃ and 450℃, the photocatalytic activity of the samples decreased because the polymer structure was partially destroyed.

[0069] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a conjugated polymer photocatalyst, characterized in that, Includes the following steps: S1. Melamine and pyromellitic acid are dissolved in dimethyl sulfoxide to obtain melamine solution A and pyromellitic acid solution B, respectively. S2. Pour the solution B obtained in step S1 into solution A, stir evenly to allow melamine and trimesic acid to polymerize, then add deionized water, stir until a white precipitate is formed, centrifuge, wash and dry to obtain the conjugated polymer precursor. S3. Calcination of the conjugated polymer precursor at 350℃ in an air atmosphere yields a nanorod-shaped donor-acceptor type conjugated polymer photocatalyst.

2. The method for preparing the conjugated polymer photocatalyst according to claim 1, characterized in that: In step S1, the molar ratio of melamine to trimesic acid is (2-8):(2-8), and the volume of dimethyl sulfoxide used to dissolve both melamine and trimesic acid is 20 mL.

3. The method for preparing the conjugated polymer photocatalyst according to claim 1, characterized in that: In step S2, when solution B is poured into solution A and stirred, the stirring temperature is 60℃~120℃ and the stirring time is 0.5h~3h.

4. The method for preparing the conjugated polymer photocatalyst according to claim 1, characterized in that: In step S2, the stirring time for obtaining the white precipitate at room temperature is 0.5h to 3h.

5. The method for preparing the conjugated polymer photocatalyst according to claim 1, characterized in that: In step S3, the heating rate of calcining the conjugated polymer precursor is 2. ~10 The calcination time is 1 hour to 4 hours.

6. The conjugated polymer photocatalyst obtained by the preparation method of the conjugated polymer photocatalyst according to any one of claims 1-5.

7. The conjugated polymer photocatalyst according to claim 6 in the preparation of The application of this technology is characterized by: include: Photocatalytic preparation The performance testing process is as follows: A flat-bottomed three-necked flask was used as the reactor for photocatalytic preparation. The experiment used a 300-watt xenon lamp equipped with an AM1.5G filter as a simulated sunlight source. First, 20 mg of photocatalyst was weighed and dispersed in 50 mL of ethanol-water solution, where V 乙醇 V 水 The ratio of the solvent to water was 1:9 to form a homogeneous dispersion. Oxygen was then introduced into the three-necked flask for 30 minutes. Next, the dispersion was irradiated with a xenon lamp. During irradiation, 2 mL of the reaction solution was taken every 15 minutes and filtered through a 0.45 μm filter to obtain a clear and transparent solution. 1 mL of this clear and transparent solution was taken, and then 1 mL of 0.1 M potassium hydrogen phthalate solution and 1 mL of 0.4 M potassium iodide solution were added. The mixture was shaken well and allowed to react for 30 minutes. Finally, the absorbance of the reaction solution was measured at 350 nm in a quartz cuvette. Based on the measured absorbance and... Standard curves for quantitative analysis of photocatalytic catalyst preparation The yield; The preparation method of the conjugated polymer photocatalyst is as follows: 8 mmol of melamine was dispersed in 20 mL of dimethyl sulfoxide to form a clear and transparent solution A. 8 mmol of trimesic acid was then dispersed in 20 mL of dimethyl sulfoxide to form a clear and transparent solution B. Solution B was poured into solution A at 80 °C and stirred for 3 h. After the mixture cooled to room temperature, 200 mL of deionized water was added, and stirring continued for 3 h to obtain a white precipitate. The precipitate was washed by centrifugation with anhydrous ethanol and deionized water, and then dried at 80 °C to obtain the conjugated polymer precursor MT. MT was calcined in air at 350 °C for 2 h at a heating rate of 10 °C / min. -1 This yielded a nanorod-shaped donor-acceptor conjugated polymer, named MT350, which was prepared by photocatalysis. The yield was 451.3 μmol·h⁻¹. -1 ·g -1 .

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