A thermoelectric enhanced photocatalytic cilia array and its preparation method

Abstract

The present invention belongs to the technical field of the preparation of functional composite materials, and particularly relates to a thermoelectric enhanced photocatalytic cilia array and a preparation method thereof. The present invention prepares a flexible cilia substrate by magnetic field-induced self-assembly, and loads a thermoelectric material and a photocatalyst by a self-assembly method. When the present invention is used for photocatalytic degradation of organic pollutants, the part loaded with the photocatalyst is immersed in an aqueous solution, and the thermoelectric material can directly absorb near-infrared light to generate heat, and by virtue of the difference in the thermal conductivities of water and air, a temperature difference is generated to excite the thermoelectric effect to separate photo-generated electron-hole pairs, thereby improving the photocatalytic performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of functional composite materials, and particularly relates to a thermoelectric enhanced photocatalytic cilia array and a preparation method thereof. Background Art

[0002] Semiconductor photocatalysis technology plays an important role in solving energy and environmental problems. Its basic principle is that photons excite electrons in the valence band of a semiconductor photocatalyst, causing them to transition into the conduction band and leaving holes in their original positions. However, photo-generated electron-hole pairs are prone to recombination, which limits the performance of the photocatalyst. Research shows that by constructing an electric field to achieve the separation of photo-generated electron-hole pairs, the reaction rate of the photocatalyst can be effectively improved. Thermoelectric materials have the Seebeck effect and can generate a potential difference when there is a temperature difference at both ends. This potential difference can cause photo-generated electrons to migrate towards the direction of higher potential, and photo-generated holes to migrate towards the direction of lower potential, realizing the separation of photo-generated electron-hole pairs during the photocatalysis process. On the other hand, the low utilization rate of the solar spectrum is also an important factor restricting the improvement of photocatalytic performance. Low-energy photons in the near-infrared light cannot excite valence band electrons, resulting in a large amount of energy in solar energy being wasted during the photocatalysis process. Chinese Patent CN114749169A loads a photocatalyst on a thermoelectric substrate made of a thermoelectric material to improve the degradation performance of the photocatalyst; Chinese Patent CN103551198B loads a photocatalyst on a surface-modified ciliated bionic array, and this photocatalytic array realizes efficient mixing and mass transfer in the catalytic system and obtains good photocatalytic activity in a high-speed rotating magnetic field. However, the above technologies need to use additional energy and introduce other media during use to achieve the technical effect of improving the photocatalytic degradation ability. Therefore, exploring a simple method to simultaneously improve the solar spectrum utilization rate and separate photo-generated carriers is of great significance for the industrial application of semiconductor photocatalysis technology. Summary of the Invention

[0003] To solve the above problems, the present invention proposes a thermoelectric enhanced photocatalytic cilia array and a preparation method thereof.

[0004] The technical solution of the present invention is as follows:

[0005] A thermoelectric enhanced photocatalytic cilia array includes a flexible cilia array substrate, a thermoelectric material, and a photocatalyst; the thermoelectric material is coated on the surface of the flexible cilia substrate to form a thermoelectric cilia array, the thermoelectric cilia array is divided into a loading area and a non-loading area, and the photocatalyst is loaded on the loading area of the thermoelectric cilia array; the thermoelectric material is a conductive polymer with good absorption in the near-infrared light band.

[0006] Preferably, the conductive polymer is hydrochloric acid-doped polyaniline (HCl-PANI) or poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), which can be deposited on the flexible cilia substrate by a self-assembly method.

[0007] Preferably, the photocatalyst is any one of carbon nitride (C3N4), cadmium sulfide (CdS), and zinc oxide (ZnO).

[0008] The method for preparing the thermoelectric enhanced photocatalytic cilia array includes the following steps:

[0009] (1) Dissolve the main raw material of the cilia substrate in N,N-dimethylformamide, add cobalt powder, stir and disperse evenly to obtain a substrate precursor solution. Then pour the substrate precursor solution into a polytetrafluoroethylene mold and place it in a magnetic field to induce the self-assembly of cobalt powder. Then heat at 50-80 °C for 2-8 h to volatilize the solvent and obtain a flexible cilia substrate;

[0010] (2) Immerse the flexible cilia substrate in a mixed solution composed of a thermoelectric material and a Nafion ethanol solution, and heat at 50-70 °C for 0.5-2 h to volatilize the solvent to obtain a thermoelectric cilia array;

[0011] (3) Immerse the loading area of the thermoelectric cilia array in a mixed solution composed of a photocatalyst and a Nafion ethanol solution, and heat at 50-70 °C for 0.5-2 h to volatilize the solvent to obtain a thermoelectric enhanced photocatalytic cilia array.

[0012] Preferably, in step (1), the cobalt powder accounts for 5%-30% of the mass of the main raw material of the cilia substrate; the main raw material of the cilia substrate is any one of polyvinylidene fluoride (PVDF), polydimethylsiloxane (PDMS), and polyurethane (PU).

[0013] Preferably, the magnetic field strength in step (1) is 1000-10000 Gs.

[0014] Preferably, in step (2), the thermoelectric material accounts for 0.1%-3% of the mass of the Nafion ethanol solution.

[0015] Preferably, in step (3), the photocatalyst accounts for 0.1%-1% of the mass of the Nafion ethanol solution.

[0016] The thermoelectric enhanced photocatalytic cilia array is applied to photocatalytic degradation of organic pollutants: Immerse the part of the thermoelectric enhanced photocatalytic cilia array loaded with the photocatalyst in a solution containing organic pollutants, and carry out a photocatalytic reaction under sunlight irradiation to degrade the organic pollutants.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. When the thermoelectric enhanced photocatalytic cilia array of the present invention is in use, the part loaded with the photocatalyst is immersed in an aqueous solution, and the thermoelectric material in the non-loaded area is exposed to the air, which can directly absorb near-infrared light to generate heat. Utilizing the difference in thermal conductivity between water and air, a temperature difference is generated between the loaded area and the non-loaded area of the thermoelectric enhanced photocatalytic cilia array, exciting the thermoelectric effect, separating photo-generated electron-hole pairs, and improving the photocatalytic efficiency.

[0019] 2. The present invention does not need to introduce additional energy. Only by using the near-infrared light naturally present in sunlight to generate heat, the technical effect of exciting the thermoelectric effect can be achieved, and at the same time, the problems of low utilization rate of the solar spectrum and easy recombination of photo-generated electron-hole pairs are solved.

[0020] 3. The flexible cilia substrate of the present invention expands the contact area between the photocatalyst and the solution, and improves the light utilization rate through an antireflection structure.

[0021] 4. The present invention adopts a self-assembly method to load the thermoelectric material and the photocatalyst on the flexible cilia substrate. The preparation method is simple and has good universality. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the thermoelectric enhanced photocatalytic cilia array, where the reference numerals are: 1. Non-loaded area exposed to the air, 2. Loaded area immersed in the aqueous solution, 3. Flexible cilia substrate, 4. Thermoelectric material layer, 5. Photocatalyst layer;

[0023] Figure 2 It is a comparison diagram of the photocatalytic performance of Example 1 and Comparative Example 1;

[0024] Figure 3 It is a comparison diagram of the photocatalytic performance of Example 2 and Comparative Example 2;

[0025] Figure 4 It is a comparison diagram of the photocatalytic performance of Example 3 and Comparative Example 1;

[0026] Figure 5 It is a comparison diagram of the photocatalytic performance of Example 1 and Comparative Example 3. Detailed Embodiments

[0027] In order to further understand the present invention, the present invention will be described below in conjunction with embodiments. These descriptions are only to further explain the features and advantages of the present invention and are not used to limit the claims of the present invention.

[0028] Example 1

[0029] (1) Take 10 g of polyvinylidene fluoride, dissolve it in 100 mL of N,N-dimethylformamide, add 1 g of cobalt powder, stir and disperse evenly to obtain a substrate precursor solution; then take 5 mL of the substrate precursor solution, pour it into a 27×27×7 mm rectangular polytetrafluoroethylene mold, place the mold in a magnetic field of 6000 Gs, and heat at 70 °C for 4 h to evaporate the solvent and obtain a flexible cilia substrate;

[0030] (2) Disperse 50 mg of hydrochloric acid-doped polyaniline (HCl-PANI) in 3.95 g of 0.5% Nafion ethanol solution, then immerse the flexible cilia substrate therein, and heat at 60 °C for 1 h to obtain a thermoelectric cilia array;

[0031] (3) Disperse 3.75 mg of carbon nitride (C3N4) in 2.37 g of 0.5% Nafion ethanol solution, then immerse the loading area of the thermoelectric cilia array therein, and heat at 60 °C for 1 h to obtain a thermoelectric enhanced photocatalytic cilia array.

[0032] Example 2

[0033] (1) Take 10 g of polyvinylidene fluoride, dissolve it in 100 mL of N,N-dimethylformamide, add 1 g of cobalt powder, stir and disperse evenly to obtain a substrate precursor solution; then take 5 mL of the substrate precursor solution, pour it into a 27×27×7 mm rectangular polytetrafluoroethylene mold, place the mold in a magnetic field of 6000 Gs, and heat at 70 °C for 4 h to obtain a flexible cilia substrate;

[0034] (2) Disperse 50 mg of hydrochloric acid-doped polyaniline (HCl-PANI) evenly in 3.95 g of 0.5% Nafion ethanol solution, then immerse the flexible cilia substrate therein, and heat at 60 °C for 1 h to obtain a thermoelectric cilia array;

[0035] (3) Disperse 3.75 mg of cadmium sulfide (CdS) evenly in 2.37 g of 0.5% Nafion ethanol solution, then immerse the loading area of the thermoelectric cilia array therein, and heat at 60 °C for 1 h to obtain a thermoelectric enhanced photocatalytic cilia array.

[0036] Example 3

[0037] (1) Take 10 g of polyvinylidene fluoride, dissolve it in 100 mL of N,N-dimethylformamide, add 1 g of cobalt powder, stir and disperse evenly to obtain a substrate precursor solution; then take 5 mL of the substrate precursor solution, pour it into a 27×27×7 mm rectangular polytetrafluoroethylene mold, place the mold in a magnetic field of 6000 Gs, and heat at 70 °C for 4 h to obtain a flexible cilia substrate;

[0038] (2) Disperse 50 mg of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS) uniformly in 3.95 g of 0.5% Nafion ethanol solution, then immerse the flexible cilia substrate into it and heat at 60 °C for 1 h to obtain a thermoelectric cilia array;

[0039] (3) Disperse 3.75 mg of carbon nitride (C3N4) in 2.37 g of 0.5% Nafion ethanol solution, then immerse the thermoelectric cilia array loading area into it and heat at 60 °C for 1 h to obtain a thermoelectric enhanced photocatalytic cilia array.

[0040] Comparative Example 1

[0041] (1) Take 10 g of polyvinylidene fluoride, dissolve it in 100 mL of N,N-dimethylformamide, add 1 g of cobalt powder, stir and disperse evenly to obtain a substrate precursor solution; then take 5 mL of the substrate precursor solution, pour it into a 27×27×7 mm rectangular polytetrafluoroethylene mold, place the mold in a 6000 Gs magnetic field, and heat at 70 °C for 4 h to volatilize the solvent and obtain a flexible cilia substrate;

[0042] (2) Disperse 3.75 mg of carbon nitride (C3N4) in 2.37 g of 0.5% Nafion ethanol solution, then immerse the flexible cilia substrate into it and heat at 60 °C for 1 h to obtain a photocatalytic cilia array.

[0043] Comparative Example 2

[0044] (1) Take 10 g of polyvinylidene fluoride, dissolve it in 100 mL of N,N-dimethylformamide, add 1 g of cobalt powder, stir and disperse evenly to obtain a substrate precursor solution; then take 5 mL of the substrate precursor solution, pour it into a 27×27×7 mm rectangular polytetrafluoroethylene mold, place the mold in a 6000 Gs magnetic field, and heat at 70 °C for 4 h to obtain a flexible cilia substrate;

[0045] (2) Disperse 3.75 mg of cadmium sulfide (CdS) uniformly in 2.37 g of 0.5% Nafion ethanol solution, then immerse the flexible cilia substrate into it and heat at 60 °C for 1 h to obtain a photocatalytic cilia array.

[0046] Comparative Example 3

[0047] (1) Take 10 g of polyvinylidene fluoride, dissolve it in 100 mL of N,N-dimethylformamide, add 1 g of cobalt powder, stir and disperse evenly to obtain a substrate precursor solution; then take 5 mL of the substrate precursor solution, pour it into a 27×27×7 mm rectangular polytetrafluoroethylene mold, and heat at 70 °C for 4 h to volatilize the solvent and obtain a flexible thin film substrate;

[0048] (2) Disperse 50 mg of hydrochloric acid-doped polyaniline (HCl-PANI) in 3.95 g of 0.5% Nafion ethanol solution, then immerse the flexible film substrate into it and heat at 60 °C for 1 h to obtain a thermoelectric film;

[0049] (3) Disperse 3.75 mg of carbon nitride (C3N4) in 2.37 g of 0.5% Nafion ethanol solution, then immerse the thermoelectric film into it and heat at 60 °C for 1 h to obtain a thermoelectric enhanced photocatalytic film.

[0050] The photocatalytic performance was evaluated by photocatalytic degradation of methyl orange solution. The specific operation was as follows: Immerse the photocatalyst-loaded part of the thermoelectric enhanced photocatalytic cilia array into 50 mL of methyl orange solution, use a 300 W full-spectrum xenon lamp to simulate sunlight, and carry out a light irradiation reaction for 90 min.

[0051] Figure 2 It is a photocatalytic performance comparison chart between Example 1 and Comparative Example 1. It can be seen that when the thermoelectric material HCl-PANI is loaded, the photocatalytic degradation rate of C3N4 increases from 71.5% to 93.5%, and the reaction efficiency constant is 2.18 times that without loading the thermoelectric material.

[0052] Figure 3 It is a photocatalytic performance comparison chart between Example 2 and Comparative Example 2. It can be seen that when the thermoelectric material HCl-PANI is loaded, the photocatalytic degradation rate of CdS increases from 64.3% to 91.4%, and the reaction efficiency constant is 2.38 times that without loading the thermoelectric material.

[0053] Figure 4 It is a photocatalytic performance comparison chart between Example 3 and Comparative Example 1. It can be seen that when the thermoelectric material PEDOT:PSS is loaded, the photocatalytic degradation rate of C3N4 increases from 71.5% to 90.0%, and the reaction efficiency constant is 1.91 times that without loading the thermoelectric material.

[0054] Figure 5 It is a photocatalytic performance comparison chart between Example 1 and Comparative Example 3. It can be seen that compared with using a polyvinylidene fluoride film as the substrate material, the photocatalytic degradation rate of the C3N4 / PANI photocatalytic cilia array increases from 58.0% to 93.5%, and the reaction efficiency constant is 3.14 times that of the film.

Claims

1. A thermoelectric enhanced photocatalytic cilia array, characterized in that, It includes a flexible cilia array substrate, a thermoelectric material, and a photocatalyst; the thermoelectric material is coated on the surface of the flexible cilia substrate (3) to form a thermoelectric cilia array (4), the thermoelectric cilia array is divided into two parts, a lower loading area (2) and an upper non-loading area (1), and the photocatalyst is loaded on the loading area (2) of the thermoelectric cilia array to form a photocatalyst layer (5); the thermoelectric material is a conductive polymer that has absorption in the near-infrared light band.

2. The thermoelectric enhanced photocatalytic cilia array according to claim 1, wherein The conductive polymer is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid or hydrochloric acid-doped polyaniline.

3. The thermoelectric enhanced photocatalytic cilia array according to claim 1, wherein The photocatalyst is any one of carbon nitride, cadmium sulfide, and zinc oxide.

4. The method for preparing the thermoelectric enhanced photocatalytic cilia array according to any one of claims 1-3, characterized in that, It includes the following steps: (1) Dissolve the main raw material of the cilia substrate in N,N-dimethylformamide, add cobalt powder, stir and disperse to obtain a substrate precursor solution, then pour the substrate precursor solution into a polytetrafluoroethylene mold, and place it in a magnetic field to induce self-assembly of cobalt powder, and then heat at 50-80 °C for 2-8 h to obtain a flexible cilia substrate; (2) Immerse the flexible cilia substrate in a mixed solution composed of a thermoelectric material and a Nafion ethanol solution, and heat at 50-70 °C for 0.5-2 h to obtain a thermoelectric cilia array; (3) Immerse the loading area of the thermoelectric cilia array in a mixed solution composed of a photocatalyst and a Nafion ethanol solution, and heat at 50-70 °C for 0.5-2 h to obtain a thermoelectric enhanced photocatalytic cilia array.

5. The preparation method of the thermoelectric enhanced photocatalytic cilia array according to claim 4, characterized in that, In step (1), the cobalt powder accounts for 5%-30% of the mass of the main raw material of the cilia substrate.

6. The preparation method of the thermoelectric enhanced photocatalytic cilia array according to claim 4, characterized in that, In step (1), the main raw material of the cilia substrate is any one of polyvinylidene fluoride, polydimethylsiloxane, and polyurethane.

7. The preparation method of the thermoelectric enhanced photocatalytic cilia array according to claim 4, characterized in that, In step (1), the magnetic field strength is 1000-10000 Gs.

8. The preparation method of the thermoelectric enhanced photocatalytic cilia array according to claim 4, wherein In step (2), the thermoelectric material accounts for 0.1%-3% of the mass of the Nafion ethanol solution.

9. The preparation method of the thermoelectric enhanced photocatalytic cilia array according to claim 4, characterized in that, In step (3), the photocatalyst accounts for 0.1%-1% of the mass of the Nafion ethanol solution.

10. Application of the thermoelectric enhanced photocatalytic cilia array according to any one of claims 1-3 in photocatalytic degradation of organic pollutants.

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