A photosensitive metal complex film and its preparation method and application

Abstract

The present invention discloses a photosensitive metal complex film and a preparation method and application thereof. The photosensitive metal complex film comprises a metal complex and perovskite quantum dots coated on the surface of the metal complex; the coating amount is 1-2 mg; the coating area is 1×2 cm 2 ; The photosensitive metal complex film can inhibit the recombination of photogenerated carriers, facilitate the electron transfer between molecules, improve the photocatalytic performance, and can be applied to photocatalytic carbon dioxide reduction.

Description

Technical Field

[0001] The invention relates to the technical field of metal complex film, and in particular to a photosensitive metal complex film and a preparation method and application thereof. Background Art

[0002] With the development of the times and the continuous growth of the global population, the demand for energy worldwide will continue to increase. At present, fossil energy such as oil, natural gas, and coal are still the main energy sources. The continuous increase in fossil energy consumption has caused various environmental problems, and the development of alternative sustainable energy has become an urgent problem to be solved. Solar energy is considered to be an abundant, widely distributed, safe, clean, infinitely renewable energy that can meet human energy needs. Using photocatalytic technology to convert the abundant and renewable solar energy on the earth into chemical energy is an ideal way to solve environmental problems. In recent years, metal complexes have been widely used in photocatalytic reactions. Metal complexes usually have a large π-electron conjugated structure, which is conducive to their electron transfer and storage. In addition, the catalytic activity of metal complexes can be adjusted by changing the central metal ion or the surrounding ligands. However, most metal complexes also have problems such as limited response to visible light, which hinders their application in photocatalytic reactions. Perovskite is considered to be one of the most promising materials for designing efficient photocatalytic systems due to its unique photoelectric properties and structural diversity.

[0003] In the field of photocatalysis, molecular catalytic systems composed of photosensitizers and catalysts are widely used. As the center of light capture and electron transfer, photosensitizers play an irreplaceable role in sensitization centers. However, most photosensitizers need to rely on precious metal complexes, which cannot be used on a large scale due to their limited resources and high prices. Moreover, the additional addition of photosensitizers is not conducive to the charge transfer between the catalytic unit and the photosensitive unit, further affecting the photocatalytic activity. To solve this problem, it is necessary to develop new molecular complexes that meet the photosensitivity requirements. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the purpose of the present invention is to provide a photosensitive metal complex film, which can inhibit the recombination of photogenerated carriers, facilitate the electron transfer between molecules, improve the photocatalytic performance, and can be applied to photocatalytic carbon dioxide reduction.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A photosensitive metal complex film, comprising a metal complex and perovskite quantum dots coated on the surface of the metal complex; the coating amount is 1-2 mg; the coating area is 1×2 cm 2 .

[0007] In some preferred embodiments of the present invention, the metal complex comprises a bimetallic complex.

[0008] In some preferred embodiments of the present invention, the perovskite quantum dots include nanomaterials formed by the coordination of CsPbBr3 and ligands.

[0009] In some preferred embodiments of the present invention, the bimetallic complex comprises at least one of a bimetallic cobalt complex and a bimetallic copper complex.

[0010] In some preferred embodiments of the present invention, the ligand includes at least one of hexafluorophosphate, 3,5-bipyridine-4-amino-1,2,4-triazole, and 5-bromo-2-hydroxyisophthalaldehyde.

[0011] Another object of the present invention is to provide a method for preparing the photosensitive metal complex film, comprising the following steps:

[0012] The metal complex dispersion is spin-coated on a substrate, and then the perovskite dispersion is spin-coated on the surface of the metal complex to obtain a composite photosensitive metal complex film.

[0013] In some embodiments of the present invention, the concentration of the perovskite dispersion is 1 g / L to 2 g / L.

[0014] In some embodiments of the present invention, the concentration of the metal complex dispersion is 1 g / L to 2 g / L.

[0015] In some embodiments of the present invention, the usage ratio of the metal complex dispersion to the perovskite dispersion is 1:1.

[0016] In some embodiments of the present invention, the spin coating is performed by a spin coater.

[0017] In some preferred embodiments of the present invention, the rotation speed of the glue spreader is 900-2000 rpm.

[0018] In some embodiments of the present invention, in step S4, the substrate includes at least one of a glass sheet and a quartz sheet.

[0019] In some embodiments of the present invention, the preparation of the perovskite dispersion comprises the following steps:

[0020] Step S1. exchanging CsPbBr3 and ligands to obtain perovskite quantum dots;

[0021] Step S2. dispersing the perovskite quantum dots in an organic solution to obtain a perovskite dispersion;

[0022] In some embodiments of the present invention, in step S1, the ligand includes at least one of hexafluorophosphate, 3,5-bipyridine-4-amino-1,2,4-triazole, and 5-bromo-2-hydroxyisophthalaldehyde.

[0023] In some embodiments of the present invention, the preparation of the metal complex dispersion comprises the following steps:

[0024] dispersing the metal complex in an organic solution to obtain a metal complex dispersion;

[0025] In some embodiments of the present invention, the organic solution comprises at least one of n-hexane and ethyl acetate.

[0026] Another object of the present invention is to provide the application of the photosensitive metal complex film in photocatalytic CO2 reduction.

[0027] The beneficial effects of the present invention are:

[0028] (1) The present invention fixes the metal complex on the photosensitive material CsPbBr3 perovskite to prepare a photosensitive thin film composite material for photocatalytic CO2 reduction reaction, which not only reduces the use of precious metal photosensitizers, but also accelerates the charge transfer between molecules and improves the photocatalytic ability.

[0029] (2) The method of the present invention is simple to prepare, and no precious metals are involved in the synthesis process, which is suitable for practical application and has good development prospects in the field of photocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Ultraviolet-visible light absorption spectrum of the photosensitive metal complex film of Example 2.

[0031] Figure 2 HRSEM image of the photosensitive metal complex film of Example 2.

[0032] Figure 3 Photocatalytic CO2 reduction performance diagram of the photosensitive metal complex film of Example 2 and the photosensitive metal complex film of Comparative Example 1. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0034] Example 1

[0035] This embodiment provides a bimetallic cobalt complex film, and the specific process is as follows:

[0036] (1) Preparation of bimetallic cobalt complex (Co2L):

[0037] Dissolve Co(NO3)2·6H2O (12 mg) in anhydrous ethanol (2 mL), and dissolve the ligand 3,5-dipyridine-4-amino-1,2,4-triazole (10 mg) in dichloromethane (2 mL). Mix the Co(NO3)2·6H2O solution and the ligand solution, stir at room temperature overnight, filter to obtain an orange-red powder, and dry overnight to obtain a bimetallic cobalt complex.

[0038] (2) Bimetallic cobalt complex films of composite perovskite (CsPbBr3-PF6 - -Co2) preparation:

[0039] The bimetallic cobalt complex (1 mg) was dispersed in ethyl acetate (1 ml) and ultrasonicated for 20-30 min to obtain a bimetallic cobalt complex dispersion. - (1mg) was dispersed in ethyl acetate (1ml) solution and ultrasonicated for 20-30min to obtain a perovskite dispersion. Then, 50μL of the bimetallic cobalt complex dispersion was taken and spin-coated onto a glass sheet using a 900-2000rpm gel coater. After the solvent evaporated, another 50μL of the perovskite dispersion was taken and spin-coated onto the glass sheet and placed at room temperature until the solvent evaporated completely. Repeat the above operation with the remaining bimetallic cobalt complex dispersion and perovskite dispersion to obtain a photosensitive metal complex film CsPbBr3-PF6 with a layered structure in which the bimetallic cobalt complex layer and the perovskite layer alternate continuously. - -Co2.

[0040] Example 2

[0041] This embodiment provides a bimetallic copper complex film, and the specific process is as follows:

[0042] (1) Preparation of bimetallic copper complex (Cu2L1):

[0043] Dissolve N, N-dimethyl-1,3-diaminopropane (1.5 mmol) in anhydrous ethanol (15 ml), add to an ethanol solution (15 ml) of 2,6-diformyl-4-bromophenol (1.5 mmol), then add copper perchlorate hexahydrate (1.5 mmol, 0.556 g) and triethylamine (1 ml), stir at room temperature for 20 hours, stop the reaction, filter, and obtain a bimetallic copper complex.

[0044] (2) Bimetallic copper complex films of composite perovskite (CsPbBr3-PF6 - -Cu2) preparation:

[0045] The bimetallic copper complex (2 mg) was dispersed in ethyl acetate (2 ml) solution and ultrasonicated for 20-30 min to obtain a bimetallic copper complex dispersion. - (2mg) was dispersed in ethyl acetate (2ml) solution and ultrasonicated for 20-30min to obtain a perovskite dispersion. Then, 50μL of the bimetallic copper complex dispersion was taken and spin-coated on a glass sheet by a 900-2000rpm gel coater. After the solvent evaporated, another 50μL of the perovskite dispersion was taken and spin-coated on the glass sheet and placed at room temperature until the solvent evaporated completely. Repeat the above operation with the remaining bimetallic copper complex dispersion and perovskite dispersion to obtain a photosensitive metal complex film CsPbBr3-PF6 with a layered structure in which the bimetallic copper complex layer and the perovskite layer alternate continuously. - -Cu2.

[0046] Comparative Example 1

[0047] This comparative example prepares a bimetallic copper complex film. The difference from Example 2 is that the preparation method of the photosensitive metal complex film is different. Example 2 is spin coating by a coating machine, while Comparative Example 1 is direct manual drop coating. The specific process is as follows:

[0048] The steps in Example 2 are as follows: "absorb 50 μL of the bimetallic copper complex dispersion, and spin coat it onto a glass sheet using a homogenizer with a rotation speed of 900-2000 rpm. After the solvent has evaporated, absorb 50 μL of the perovskite dispersion and drop it thereon, and place it at room temperature until the solvent has completely evaporated." is replaced with "absorb 50 μL of the bimetallic copper complex dispersion, and manually drop coat it onto a glass sheet using a dropper. After the solvent has evaporated, absorb 50 μL of the perovskite dispersion and drop it thereon, and place it at room temperature until the solvent has completely evaporated." The remaining steps are the same as in Example 2.

[0049] Performance Test:

[0050] Depend on Figure 1 It can be seen that the photosensitive metal complex film was tested in a methanol solution using a UV-3600 ultraviolet-visible spectrophotometer, with a test range of 400-700nm. The experimental results show that the film formed by fixing the bimetallic copper complex on the perovskite through a sizing machine has a good absorption in the visible light range, which provides a basis for the photocatalytic carbon dioxide reduction reaction.

[0051] Depend on Figure 2It can be seen that the material composition was analyzed using a high-resolution transmission electron microscope (HRTEM) of model FEI Talos F200X. Figure 2 The first picture is the overall morphology of the film under an electron microscope, and the second to sixth pictures are the distribution of different elements in the same area of ​​the film. The test sample preparation method is: disperse a small amount of sample in the solvent, ultrasonicate for 10-20 minutes, absorb a small amount and disperse it on the ultra-thin carbon film, and observe the microscopic morphology of the material under a transmission electron microscope after the solvent evaporates. The experimental results show that: CsPbBr3-PF6 - -Cu2 film includes five elements, Cs, Pb, Br, Cu, and P, and the five elements are evenly distributed on the film. Copper elements were observed on the surface of perovskite, indicating that the metal copper complex was successfully fixed on the perovskite.

[0052] Depend on Figure 3 It can be seen that: using a 300W xenon lamp as the light source and a 400nm filter, the photocatalytic reaction system is: thin film CsPbBr3-PF6 - -Cu2 was used as the catalyst and 30μL of water as the reaction system. CO2 was used to ventilate for 20-30min to remove oxygen from the solution, and the photocatalytic CO2 reduction experiment was carried out after sealing. The reduction products of CO and CH3OH can be detected after 4 hours of illumination. From the experimental results, it can be seen that the methanol production of the spin coating by the coater is 26 times that of the direct drop coating, and the CO production is 11.6 times that of the direct drop coating. This may be because the use of the coater spin coating makes the film more uniform, exposes more catalytic active sites, and greatly improves the performance.

[0053] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A photosensitive metal complex film, characterized in that: The photosensitive metal complex film includes a metal complex and perovskite quantum dots coated on the surface of the metal complex; the coating amount is 1-2 mg; the coating area is 1×2 cm 2 ; The metal complex includes a bimetallic complex; the perovskite quantum dots include nanomaterials formed by the coordination of CsPbBr3 and a ligand; the bimetallic complex includes at least one of a bimetallic cobalt complex and a bimetallic copper complex; the ligand includes at least one of hexafluorophosphate, 3,5-dipyridine-4-amino-1,2,4-triazole, and 5-bromo-2-hydroxyisophthalaldehyde.

2. The method for preparing a photosensitive metal complex film according to claim 1, characterized in that: The steps include: The metal complex dispersion is spin-coated on a substrate, and then the perovskite dispersion is spin-coated on the surface of the metal complex to obtain a composite photosensitive metal complex film.

3. The method for preparing a photosensitive metal complex film according to claim 2, characterized in that: The concentration of the perovskite dispersion is 1 g / L to 2 g / L; the concentration of the metal complex dispersion is 1 g / L to 2 g / L.

4. The method for preparing a photosensitive metal complex film according to claim 2, characterized in that: The mass dosage ratio of the metal complex dispersion liquid to the perovskite dispersion liquid is 1:

1.

5. The method for preparing a photosensitive metal complex film according to claim 2, characterized in that: The preparation of the perovskite dispersion comprises the following steps: Step S1. Coordinate CsPbBr3 with a ligand to obtain perovskite quantum dots; Step S2: dispersing the perovskite quantum dots in an organic solution to obtain a perovskite dispersion.

6. The method for preparing a photosensitive metal complex film according to claim 5, characterized in that: In step S1, the ligand includes at least one of hexafluorophosphate, 3,5-bipyridine-4-amino-1,2,4-triazole, and 5-bromo-2-hydroxyisophthalaldehyde.

7. The method for preparing a photosensitive metal complex film according to claim 2, characterized in that: The preparation of the metal complex dispersion comprises the following steps: The metal complex is dispersed in an organic solution to obtain a metal complex dispersion.

8. Use of the photosensitive metal complex film according to claim 1 in photocatalytic CO2 reduction.

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