A piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, a preparation method and application thereof

Abstract

The application provides a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film and a preparation method and application thereof, and relates to the technical field of catalytic materials. P(VDF-TrFE) and MoO3 are dissolved into a solvent to obtain a casting solution; the casting solution is spin-coated onto a substrate and dried to obtain the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film. The piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film prepared by the application has high degradation efficiency on dyes, and the preparation method is simple and low in cost.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of catalytic materials, in particular to a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film and a preparation method and application thereof. BACKGROUND

[0002] Polyvinylidene fluoride (PVDF) film has positive piezoelectric effect and inverse piezoelectric effect, which are coupled with each other. The existence of piezoelectric effect is due to the fact that the piezoelectric material will produce deformation such as stretching or compression under mechanical force, thereby causing the directional movement of charged particles to the electrode, which is the positive piezoelectric effect. If the piezoelectric material in normal state is subjected to an electric field, mechanical deformation will occur, which is the inverse piezoelectric effect. However, since the electric signal emitted by the PVDF film is very small, some composite materials must be used to make it truly usable.

[0003] When the piezoelectric material deforms under external force, the bias voltage formed by the internal piezoelectric potential can change the polarization charge distribution on the surface of the material, thereby causing the energy change of the valence band and the conduction band position of the material, driving the occurrence of a specific electrochemical reaction (depending on the corresponding redox potential). Therefore, the piezoelectric material can be combined with the photocatalytic material, which can not only improve the photocatalytic efficiency, but also make full use of renewable energy sources (such as wind energy, water wave energy and solar energy) in nature, and through the design of the electronic structure of the material, it is expected to play the best energy environmental benefits.

[0004] The mechanism of photocatalytic removal of pollutants is to excite the catalyst by light, promote the separation of carriers into electrons and holes, and react with oxygen or water on the surface of the catalyst to generate superoxide or hydroxyl radicals, so as to achieve the purpose of degrading pollutants through redox reaction with pollutants. However, this traditional photocatalytic mechanism generally has problems such as low photocatalytic efficiency, high electron and hole recombination rate, etc.

[0005] Chinese patent CN 115369567 A discloses a piezoelectric photocatalytic nanocomposite fiber film for dye degradation and a preparation method thereof. The modified pyridyl conjugated microporous polymer / poly(vinylidene fluoride-trifluoroethylene) composite fiber film is prepared by electrospinning method, and has high degradation efficiency. However, the electrospinning film preparation method is complex, the film preparation time is long, and the cost is high. Chinese patent CN 115057518 A discloses a device and method for water flow driven enhanced piezoelectric photocatalytic degradation of organic dyes. The application adopts the principle of generating water flow by potential energy and interacting with photocatalytic materials with piezoelectric properties, designs a water flow driven enhanced piezoelectric photocatalytic device, and is used for degradation of organic dyes. It has the advantages of simple operation and short degradation time, but the degradation efficiency is low. SUMMARY

[0006] The application aims to provide a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, a preparation method and application thereof.

[0007] In order to achieve the above-mentioned application purposes, the application provides the following technical solutions.

[0008] The application provides a preparation method of a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, comprising the following steps.

[0009] Dissolving P(VDF-TrFE) and MoO3 into a solvent to obtain a casting solution;

[0010] Rotating and coating the casting solution on a substrate, and drying to obtain the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film.

[0011] Preferably, the relative molecular weight of P(VDF-TrFE) is 300000-1500000.

[0012] Preferably, the MoO3 is monoclinic molybdenum trioxide, hexagonal molybdenum trioxide or orthorhombic molybdenum trioxide.

[0013] Preferably, the solvent is N,N-dimethylformamide, dimethyl sulfoxide or N,N-dimethylacetamide.

[0014] Preferably, the mass of MoO3 is 50-80% of the total mass of P(VDF-TrFE) and MoO3.

[0015] Preferably, the mass of P(VDF-TrFE) is 15-30% of the mass of the solvent.

[0016] Preferably, the drying is vacuum drying.

[0017] Preferably, the speed of the rotating and coating is 800-1500 r / min, and the time is 20-60 s.

[0018] The application provides a piezoelectric photocatalytic MoO3 / PVDF nanocomposite film prepared by the preparation method.

[0019] The application provides an application of the piezoelectric photocatalytic MoO3 / PVDF nanocomposite film in degrading organic pollutants.

[0020] The application provides a preparation method of a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, and comprises the following steps: dissolving P(VDF-TrFE) and MoO3 into a solvent to obtain a casting solution; and performing spin coating on a substrate to obtain the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film after drying.

[0021] The application can expose a large number of catalyst active sites by the mixed spin coating method, and promote the photocatalytic efficiency of the catalyst.

[0022] Compared with the core-shell structure of the electrostatic spinning method, the application has the advantages of low preparation cost and good stability.

[0023] The results of the examples show that the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film can effectively degrade organic pollutants.

[0024] Further, compared with ordinary drying, the application can retain the crystal phase of the MoO3 particles.

[0025] The application not only solves the problem of difficult processing of the piezoelectric photocatalytic polymer composite film, but also enhances the catalytic efficiency of the piezoelectric material, widens the practical application of sewage treatment, and has a wide application prospect in the field of mechanical energy-chemical energy conversion. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The degradation efficiency of rhodamine B by the comparative examples 1-5 and the examples 1-3 is shown in the figure. DETAILED DESCRIPTION

[0027] The application provides a preparation method of a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, and comprises the following steps: dissolving P(VDF-TrFE) and MoO3 into a solvent to obtain a casting solution; and performing spin coating on a substrate to obtain the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film after drying.

[0028] In the application, the raw materials used are all commercially available goods well known in the art, unless otherwise specified.

[0029] The P(VDF-TrFE) and MoO3 are dissolved in a solvent to obtain a casting solution.

[0030] In the present application, the relative molecular weight of the P(VDF-TrFE) is preferably 300000-1500000, more preferably 500000-1200000, and further preferably 800000-1000000; and the form of the P(VDF-TrFE) is preferably powder. In the present application, the P(VDF-TrFE) is named as polyvinylidene fluoride-trifluoroethylene in Chinese, and the trade name of the P(VDF-TrFE) in the examples of the present application is AKEMA 30. In the present application, the MoO3 is preferably monoclinic molybdenum trioxide, hexagonal molybdenum trioxide or orthorhombic molybdenum trioxide; and the form of the MoO3 is preferably nanoparticle. In the present application, the solvent is preferably N,N-dimethylformamide (DMF), dimethyl sulfoxide or N,N-dimethylacetamide, and more preferably DMF. In the present application, the mass of the P(VDF-TrFE) is preferably 15-30% of the mass of the solvent, more preferably 18-25%, and further preferably 20-23%. In the present application, the mass of the MoO3 is preferably 50-80% of the total mass of the P(VDF-TrFE) and MoO3, more preferably 55-75%, and further preferably 60-70%. In the present application, the dissolving preferably comprises: adding the P(VDF-TrFE) powder and the MoO3 nanoparticle into the solvent, and mixing and stirring for one day.

[0031] After obtaining the casting solution, the casting solution is spin-coated on a substrate, dried to obtain a piezoelectric photocatalytic MoO3 / PVDF nanocomposite film.

[0032] The substrate in the present application has no special requirements, and can be selected according to actual needs. In the examples of the present application, the substrate is a glass slide.

[0033] In the present application, the speed of the spin-coating is preferably 800-1500 r / min, more preferably 900-1400 r / min, and further preferably 1000-1300 r / min; and the time of the spin-coating is preferably 20-60 s, more preferably 30-50 s, and further preferably 35-45 s.

[0034] The application can expose a large number of active sites by mixing and spin coating, and promote the photocatalytic efficiency of the catalyst. Compared with the traditional method of spin coating first and then loading on the surface, the structure obtained by mixing and then spin coating has the advantages of uniform distribution of active components and reduction of cluster aggregation. Moreover, by controlling the parameters of spin coating within the above range, the catalyst active sites are greatly exposed, and a piezoelectric field is directionally constructed, thereby promoting the photocatalytic efficiency of the catalyst to the greatest extent.

[0035] In the application, the drying is preferably vacuum drying, and the application does not have special requirements for the vacuum degree of the vacuum drying, which is well known in the art. In the application, the temperature of the vacuum drying is preferably 80-150 DEG C, more preferably 90-140 DEG C, and further preferably 100-130 DEG C; and the time of the drying is preferably 1-4 hours, more preferably 2-3 hours. The application uses vacuum drying, which can retain the crystal phase of the molybdenum trioxide particles, thereby being beneficial to improving the photocatalytic efficiency of the MoO3 / P(VDF-TrFE) nanocomposite film. In addition, the application uses vacuum drying, which can also promote film formation.

[0036] After the vacuum drying, the application preferably further comprises peeling the MoO3 / P(VDF-TrFE) nanocomposite film from the substrate.

[0037] The application provides the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film prepared by the preparation method described in the above scheme, which comprises MoO3 and P(VDF-TrFE). The application prepares the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film by the method of mixing and then spin coating, realizes the directional and stable combination of molybdenum trioxide and P(VDF-TrFE), improves the separation rate of the electron-hole pairs of the catalyst, and improves the photocatalytic efficiency.

[0038] The application provides the application of the piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film described in the above scheme in degrading organic pollutants. In the application, the organic pollutants preferably comprise organic dyes; and the organic dyes preferably comprise rhodamine B.

[0039] The application does not have special requirements for the conditions of the application, and the application conditions well known in the art can be used. In the embodiments of the application, a 300W xenon lamp is used as a light source, and the wavelength is 400-780 nm, and the degradation experiment is carried out in an adsorption tube.

[0040] The piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, the preparation method and the application thereof provided by the application are described in detail below in combination with embodiments, but they should not be understood as limitations to the protection scope of the application.

[0041] Example 1

[0042] P(VDF-TrFE) powder (0.50 g, molecular weight 800000) and hexagonal phase molybdenum trioxide nanoparticles (0.500 g) were weighed into a mixture with a mass ratio of 1:1, dissolved in DMF solvent, so that the P(VDF-TrFE) powder accounted for 15wt% of DMF, and mixed and stirred for one day to form a casting solution. At room temperature, the casting solution was dropped on a glass slide for spin coating, with a rotation speed of 1500 r / min for 30 seconds, and the glass slide was placed in a vacuum drying oven for drying at 100°C for 2 hours to obtain a piezoelectric photocatalytic MoO3 / PVDF nanocomposite film. The film was taken out and placed in an adsorption device (adsorption tube length 15 cm, tube diameter 2.5 cm), a 300W xenon lamp was used as the light source, and 5mg / L rhodamine B was added to the tube. The degradation efficiency of rhodamine B was 60% within one hour.

[0043] Example 2

[0044] P(VDF-TrFE) powder (0.333 g, molecular weight 300000) and monoclinic phase molybdenum trioxide nanoparticles (0.667 g) were weighed into a mixture with a mass ratio of 1:2, dissolved in dimethyl sulfoxide solvent, so that the P(VDF-TrFE) powder accounted for 23wt% of dimethyl sulfoxide, and mixed and stirred for one day to form a casting solution. At room temperature, the casting solution was dropped on a glass slide for spin coating, with a rotation speed of 1500 r / min for 60 seconds, and the glass slide was placed in a vacuum drying oven for drying at 80°C for 4 hours. A piezoelectric photocatalytic MoO3 / PVDF nanocomposite film was obtained. The film was taken out and placed in an adsorption device (adsorption tube length 15 cm, tube diameter 2.5 cm), a 300W xenon lamp was used as the light source, and 5mg / L rhodamine B was added to the tube. The degradation efficiency of rhodamine B was 80% within one hour.

[0045] Example 3

[0046] P(VDF-TrFE) powder (0.250 g, molecular weight 1500000) and orthorhombic molybdenum trioxide nanoparticles (0.750 g) were weighed into a mixture with a mass ratio of 1:4, dissolved in N,N-dimethylacetamide solvent, so that the P(VDF-TrFE) powder accounted for 30wt% of N,N-dimethylacetamide, and mixed and stirred for one day to form a casting solution. At room temperature, a certain amount of the casting solution was dropped on a glass slide for spin coating at a rotation speed of 800 r / min for 20 seconds, and the glass slide was placed in a vacuum drying oven for drying at 150°C for 1 hour to obtain a piezoelectric photocatalytic MoO3 / PVDF nanocomposite film. The film was taken out and placed in an adsorption device (adsorption tube length 15 cm, tube diameter 2.5 cm), a 300W xenon lamp was used as a light source, and 5mg / L rhodamine B was added to the tube. The degradation efficiency of rhodamine B was 95% within one hour.

[0047] Comparative Example 1

[0048] P(VDF-TrFE) powder (1.000 g, molecular weight 800000) was weighed into DMF solvent, so that the P(VDF-TrFE) powder accounted for 15wt% of DMF, and mixed and stirred for one day to form a casting solution. At room temperature, the casting solution was dropped on a glass slide for spin coating at a rotation speed of 1500 r / min for 30 seconds, and the glass slide was placed in a vacuum drying oven for drying at 100°C for 2 hours to obtain a piezoelectric photocatalytic P(VDF-TrFE) nanofilm. The film was taken out and placed in an adsorption device (adsorption tube length 15 cm, tube diameter 2.5 cm), a 300W xenon lamp was used as a light source, and 5mg / L rhodamine B was added to the tube. The degradation efficiency of rhodamine B was 25% within one hour.

[0049] Comparative Example 2

[0050] P(VDF-TrFE) powder (0.500 g, molecular weight 800000) was weighed into DMF solvent, so that the P(VDF-TrFE) powder accounted for 15wt% of DMF, and mixed and stirred for one day to form a casting solution. At room temperature, the casting solution was dropped on a glass slide for spin coating at a rotation speed of 1500 r / min for 30 seconds, and 0.500 g of MoO3 powder was evenly coated on the base film by a conventional loading method. The glass slide was placed in a vacuum drying oven for drying at 100°C for 2 hours to obtain a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film. The film was taken out and placed in an adsorption device (adsorption tube length 15 cm, tube diameter 2.5 cm), a 300W xenon lamp was used as a light source, and 5mg / L rhodamine B was added to the tube. The degradation efficiency of rhodamine B was 43% within one hour.

[0051] Comparative Example 3

[0052] The difference from Example 1 is only that the speed of spin-coating is 500 r / min, and the rest is the same as Example 1. The obtained piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film is placed in an adsorption device (the length of the adsorption tube is 15 cm, and the diameter of the tube is 2.5 cm), a 300 W xenon lamp is used as a light source, and 5 mg / L of rhodamine B is added into the tube. The degradation efficiency of rhodamine B within one hour is 15%.

[0053] Comparative Example 4

[0054] The difference from Example 1 is only that the speed of spin-coating is 2000 r / min, and the rest is the same as Example 1. The obtained piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film is placed in an adsorption device (the length of the adsorption tube is 15 cm, and the diameter of the tube is 2.5 cm), a 300 W xenon lamp is used as a light source, and 5 mg / L of rhodamine B is added into the tube. The degradation efficiency of rhodamine B within one hour is 39%.

[0055] Comparative Example 5

[0056] The difference from Example 1 is only that the time of spin-coating is 15 seconds, and the rest is the same as Example 1. The obtained piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film is placed in an adsorption device (the length of the adsorption tube is 15 cm, and the diameter of the tube is 2.5 cm), a 300 W xenon lamp is used as a light source, and 5 mg / L of rhodamine B is added into the tube. The degradation efficiency of rhodamine B within one hour is 35%.

[0057] Figure 1 The degradation efficiency of rhodamine B of Comparative Examples 1-5 and Examples 1-3 is shown in the figure. According to the data of Comparative Example 1 and Examples, the separation rate of the electron-hole pair of the catalyst is improved by combining molybdenum trioxide and P(VDF-TrFE), and the photocatalytic efficiency is improved compared with single P(VDF-TrFE). According to the results of Comparative Example 2 and Examples 1-3, compared with the traditional method of spin-coating first and then loading on the surface, the structure obtained by mixing and then spin-coating has the advantages of uniform distribution of active components and reduction of cluster aggregation, so that the MoO3 / P(VDF-TrFE) nanocomposite film has higher catalytic efficiency. According to the results of Comparative Examples 3-5 and Example 1, suitable spin-coating conditions have an important influence on the photocatalytic efficiency of the MoO3 / P(VDF-TrFE) nanocomposite film.

[0058] The above only describes the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film, characterized in that: The following steps are involved: Dissolving polyvinylidene fluoride-trifluoroethylene P (VDF-TrFE) and MoO3 in a solvent to obtain a casting solution; The casting solution is spin-coated onto a substrate and dried to obtain a piezoelectric photocatalytic MoO3 / P(VDF-TrFE) nanocomposite film; the spin-coating speed is 800-1500 r / min and the time is 20-60 s; and the drying is vacuum drying.

2. The preparation method according to claim 1, characterized in that The relative molecular weight of the P(VDF-TrFE) is 300,000-1,500,000.

3. The preparation method according to claim 1, characterized in that The MoO3 is monoclinic molybdenum trioxide, hexagonal molybdenum trioxide or orthorhombic molybdenum trioxide.

4. The preparation method according to claim 1, characterized in that The solvent is N,N-dimethylformamide, dimethyl sulfoxide or N,N-dimethylacetamide.

5. The preparation method according to any one of claims 1 to 4, characterized in that The mass of the MoO3 is 50-80% of the total mass of P(VDF-TrFE) and MoO3.

6. The preparation method according to claim 5, characterized in that The mass of the P(VDF-TrFE) is 15-30% of the mass of the solvent.

7. Use of the piezoelectric photocatalytic MoO3 / PVDF nanocomposite film prepared by the preparation method according to any one of claims 1 to 6 in the degradation of organic pollutants.

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