Preparation and application of photodeposited composite photo / piezoelectric co-catalyst Au-[DFCBA]2CuCl4 nanocrystals

Abstract

This invention relates to the field of photo / piezoelectric cocatalysis, specifically to a method for preparing Au-[3,3-difluorocyclobutylammonium]2CuCl4 nanocrystals, comprising the following steps: (1) Dissolving [DFCBA]Cl and CuCl2 in 1 mL of DMF solution respectively, mixing them and adding oleic acid as a ligand; (2) Reacting fully at room temperature for 10 min, adding 40 mL of ethyl acetate, centrifuging, washing and drying the precipitate to obtain [DFCBA]2CuCl4 nanocrystals; (3) Weighing an appropriate amount of [DFCBA]2CuCl4 nanocrystal powder and dispersing it in an ethyl acetate solution containing chloroauric acid and a sacrificial reagent, depositing Au nanoparticles on the surface of the nanocrystals by ultraviolet light irradiation to prepare the desired Au-[DFCBA]2CuCl4 nanocrystals; (4) Utilizing the characteristics of Au-[DFCBA]2CuCl4 photo / piezoelectric cocatalysis, photo / piezoelectric cocatalytic degradation of the organic pollutant Sudan Red (III) is carried out. This method is low-cost, simple to prepare, and has excellent catalytic effect. It also does not contain toxic heavy metal ions such as Pb, making it a green and environmentally friendly method for preparing composite photo / piezoelectric cocatalyst materials. It can significantly improve the performance of photocatalysts and can be widely used in the field of photo / piezoelectric cocatalytic degradation of organic pollutants.

Description

Technical Field

[0001] This invention relates to the field of photo / piezoelectric cocatalysis, specifically to a method for preparing perovskite-type photo / piezoelectric cocatalyst Au-[3,3-difluorocyclobutylammonium]2CuCl4 nanocrystals. Background Technology

[0002] With the rapid development of human industry and technology, people's living standards are rising, but environmental pollution is becoming increasingly serious. Photocatalysis technology stands out among many degradation technologies due to its green and efficient characteristics, but its catalytic performance improvement is limited by the large-scale recombination of photogenerated carriers. Meanwhile, photo / piezoelectric co-catalysis technology, which improves the separation efficiency of photogenerated carriers, can enhance the catalytic performance of photocatalysts and is considered a promising candidate for future photocatalysis technologies.

[0003] Depositing noble metal nanoparticles on the surface of photocatalyst materials by in-situ photodeposition can modify the surface properties of the materials, broaden the light absorption range of the materials, and form Schottky barriers. These barriers allow photogenerated electrons to be effectively transferred from the material's band gap to the Fermi level of the metal after excitation, promoting the effective separation of photogenerated carriers and improving the overall catalytic activity.

[0004] [3,3-Difluorocyclobutylammonium]₂CuCl₄ (hereinafter referred to as [DFCBA]₂CuCl₄) is a novel copper-based hybrid perovskite ferroelectric material with good piezoelectric properties, excellent stability at room temperature, absence of toxic heavy metal ions such as lead, a narrow band gap of approximately 2.33 eV, and good visible light absorption. Unlike common three-dimensional cubic perovskite photocatalysts, [DFCBA]₂CuCl₄ exhibits a quasi-two-dimensional layered structure. Compared to three-dimensional structures, the quasi-two-dimensional layered structure has a larger deformation space, which can polarize to generate a stronger piezoelectric field. Based on the excellent piezoelectric and photocatalytic properties of [DFCBA]₂CuCl₄, we prepared it into Au-[DFCBA]₂CuCl₄ nanocrystals (NCs) by combining ligand-assisted reprecipitation and photodeposition methods. We hope to combine the unique localized surface plasmon resonance effect of Au nanoparticles with the larger specific surface area of ​​nanomaterials to fully utilize the superior photo / piezoelectric co-catalytic performance of [DFCBA]₂CuCl₄.

[0005] According to the applicant, the preparation method of Au-[DFCBA]2CuCl4NCs photo / piezoelectric cocatalyst has not been reported before, and it is a novel method for synthesizing photo / piezoelectric cocatalysts. Summary of the Invention

[0006] The purpose of this invention is to synthesize Au-[DFCBA]2CuCl4 NCs photo / piezoelectric cocatalysts, utilizing the synergistic enhancement of photoexcitation and piezoelectric properties to improve the catalytic degradation of organic pollutants. The addition of Au nanoparticles significantly enhances the cocatalytic performance of the material. The preparation process is simple, the material does not contain toxic heavy metal ions, and the degradation process is more environmentally friendly.

[0007] The specific technical solution of the present invention is as follows:

[0008] (1) The [DFCBA]2CuCl4 photo / piezoelectric cocatalyst was prepared by ligand-assisted reprecipitation: 0.32 mmol (45.9 mg) of 3,3-difluorocyclobutylamine hydrochloride ([DFCBA]Cl) powder and 0.16 mmol (27.2 mg) of copper chloride (CuCl2) powder were weighed and dissolved in 1 mL of N-N-dimethylformamide (DMF) solution. After mixing, 250 μL of oleic acid (OA) was added and stirred thoroughly for 10 min to prepare an orange-yellow [DFCBA]2CuCl4 NCs precursor solution. Then, the precursor solution was added dropwise to a rapidly stirred ethyl acetate solution, which gradually turned into a yellow-green suspension. The suspension was centrifuged at 12000 rpm / min for 5 min, and the precipitate was washed multiple times with ethyl acetate solution. After washing, it was placed in an oven at 40 °C for 6 h to dry. The resulting yellow-green solid powder was [DFCBA]2CuCl4NCs.

[0009] (2) Au-[DFCBA]2CuCl4 composite material was prepared by in-situ photodeposition: 0.47 mmol (200 mg) of sample powder was weighed and added to 90 mL of ethyl acetate solution containing 0.12 mmol (50 mg) of chloroauric acid. Isopropanol was added as a sacrificial reagent. The reaction device was placed in the dark and stirred for 30 min to reach adsorption / desorption equilibrium. The reaction device was then irradiated with a low-pressure mercury lamp for 3 h to deposit the precipitate. After centrifugation at 12000 rpm / min for 5 min, the resulting dark green precipitate was washed three times and dried in an oven at 40 °C for 6 h. The resulting dark green powder was Au-[DFCBA]2CuCl4 NCs.

[0010] (3) Photo / piezoelectric cocatalytic degradation performance test of materials: 50 mg of sample powder ([DFCBA]2CuCl4 and Au-[DFCBA]2CuCl4 NCs) was dispersed into 90 mL of Sudan Red (III) solution with a mass concentration of 10 mg / L (ethyl acetate) and injected into the photo / piezoelectric cocatalytic reaction device. Under the irradiation of mercury lamp, the piezoelectric effect of the [DFCBA]2CuCl4 material was excited by ultrasonic vibration to perform photo / piezoelectric cocatalytic tests on the two materials respectively. After every 10 min of catalysis, 3 mL of mixed solution was taken and centrifuged. The absorbance of the supernatant was measured by UV-Vis spectrophotometer. The change in Sudan Red (III) concentration was judged based on the change in the peak value of the absorption peak.

[0011] In step (1), the volume ratio of ethyl acetate solution to DMF solution must be greater than 20:1.

[0012] In step (2), the wavelength of the light source is 254nm.

[0013] In step (3), the wavelength of the light source is 365nm.

[0014] In step (3), the photo / piezoelectric co-catalysis device is placed in an ultrasonic cleaner. Ultrasonic vibration is used to simulate the external mechanical force to excite the piezoelectric properties of the material. Combined with the irradiation of a mercury lamp to induce the photoexcitation properties of the material, the entire photo / piezoelectric co-catalysis experiment is simulated.

[0015] This patent employs a ligand-assisted reprecipitation method to prepare [DFCBA]₂CuCl₄ nanocrystalline materials, followed by in-situ photodeposition to deposit Au nanoparticles on the surface of the [DFCBA]₂CuCl₄ nanocrystals. After washing and drying, the materials can be directly used in photo / piezoelectric co-catalytic degradation experiments. This method is simple, uses readily available materials, and does not contain toxic heavy metals such as Pb, effectively improving the catalytic performance of photocatalysts. The catalytic process is green and pollution-free, conforming to the principles of green chemistry. Attached Figure Description

[0016] Figure 1 Comparison of X-ray diffraction (XRD) patterns of Au nanoparticles and [DFCBA]2CuCl4 and Au-[DFCBA]2CuCl4 NCs photo / piezoelectric cocatalysts;

[0017] Figure 2 These are scanning electron microscope (SEM) comparison images of the finished product [DFCBA]2CuCl4 (a and b) and Au-[DFCBA]2CuCl4NCs (c and d) photo / piezoelectric cocatalyst in Example 2;

[0018] Figure 3Differential thermal analysis (DSC) and thermogravimetric analysis (TGA) curves of Au-[DFCBA]2CuCl4 NCs in Example 3;

[0019] Figure 4 The UV-Vis absorption curve of Au-[DFCBA]2CuCl4 NCs in Example 4 is shown in the inset, which shows the band gap size.

[0020] Figure 5 The image shows the UV absorption spectrum of Sudan Red (III) over time and the degradation efficiency comparison graph of the finished product [DFCBA]2CuCl4 and Au-[DFCBA]2CuCl4 NCs in Example 5 during the simulated photo / piezoelectric cocatalytic degradation of Sudan Red (III) dye. Detailed Implementation

[0021] Example 1

[0022] Preparation of [DFCBA]2CuCl4 NCs: 0.32 mmol (45.9 mg) of [DFCBA]Cl powder and 0.16 mmol (27.2 mg) of CuCl2 powder were dissolved in 2 mL of LDM solution. 250 μL of OA was added, and the mixture was stirred thoroughly at room temperature for 10 min to prepare the [DFCBA]2CuCl4 NCs precursor solution. The precursor solution was then added dropwise to 40 mL of rapidly stirred ethyl acetate solution. After centrifugation at 12000 rpm / min for 5 min, the supernatant and precipitate were separated and dried.

[0023] Preparation of Au-[DFCBA]2CuCl4 NCs: 0.47 mmol (200 mg) of [DFCBA]2CuCl4 powder was dispersed in 90 mL of ethyl acetate solution containing 0.12 mmol (50 mg) of chloroauric acid. 2 mL of isopropanol was added as a sacrificial agent. After stirring in the dark at room temperature for 30 min to reach adsorption / desorption equilibrium, the mixed solution was irradiated with a 10 W / 254 nm low-pressure mercury lamp for 3 h to deposit Au nanoparticles. Finally, the resulting suspension was centrifuged, and the dark green precipitate was separated and washed three times. It was then dried in an oven at 40 °C for 6 h. Figure 1 As can be seen, all diffraction peaks correspond to the standard card, proving that we successfully introduced Au nanoparticles without destroying the structure of [DFCBA]2CuCl4 NCs.

[0024] Example 2

[0025] To characterize the microstructure of the materials, we performed SEM image characterization on the two nanocrystalline materials prepared in Example 1. Figure 2These are scanning electron microscope (SEM) comparison images of the finished [DFCBA]2CuCl4 (a and b) and Au-[DFCBA]2CuCl4NCs (c and d) photo / piezoelectric cocatalysts. The images clearly show the two-dimensional sheet-like structure of the [DFCBA]2CuCl4 material and some Au nanoparticles attached to the surface of the [DFCBA]2CuCl4 material after photodeposition.

[0026] Example 3

[0027] To confirm the existence of the ferroelectric phase transition in the Au-[DFCBA]2CuCl4 NCs material, we performed DSC and TGA characterization analyses. Figure 3 The DSC curves show that Au-[DFCBA]2CuCl4NCs underwent ferroelectric-paraelectric and paraelectric-ferroelectric phase transformations at 380 K and 365 K, respectively. The TGA curves indicate thermal decomposition at 481.2 K, with a weight loss of approximately 73.4%. These results demonstrate that Au-[DFCBA]2CuCl4NCs possess stable ferroelectric / piezoelectric properties at room temperature.

[0028] Example 4

[0029] The optical absorption properties of Au-[DFCBA]2CuCl4NCs prepared in Example 1 were analyzed by UV-Vis testing, such as... Figure 4 This is the UV-Vis curve obtained from the test. We fit it to (αhv). 2 The relationship curve between hv and ( Figure 4 (Illustration) revealed that the band gap of the sample was 2.82 eV.

[0030] Example 5

[0031] [DFCBA]2CuCl4 and Au-[DFCBA]2CuCl4 NCs photo / piezoelectric cocatalytic degradation of Sudan (III) dye: 50 mg each of the two sample powders from Example 1 were weighed and dispersed into 90 mL of a 10 mg / L Sudan (III) solution (ethyl acetate solvent), and injected into the photo / piezoelectric cocatalytic device. The piezoelectric effect was excited by ultrasonic vibration under 365 nm low-pressure mercury lamp irradiation. Every 10 min, 3 mL of the mixed solution was aspirated and centrifuged at 12000 rpm / min for 5 min. The absorbance of the resulting supernatant was measured using a UV-Vis spectrophotometer, and the change in Sudan (III) concentration was determined based on the change in the absorption peak value. Figure 5 (a) and (b) are the UV-Vis curves of Sudan Red (III) solutions at different catalytic times during the photo / piezoelectric catalytic degradation process using the two finished products obtained in Example 1. Figure 5As shown in (c), [DFCBA]2CuCl4 NCs degraded 50.8% of Sudan Red (III) in the solution within 70 min; Au-[DFCBA]2CuCl4 NCs achieved a degradation rate of 93.5% within the same time period; the performance of Au nanoparticles was significantly improved after deposition.

[0032] This patent is not limited to the above-described embodiments. Any preparation method that is the same as or similar to this patent is within the scope of protection of this patent.

Claims

1. A method for preparing the photodeposited composite photo / piezoelectric co-catalyst Au-[DFCBA]2CuCI4 nanocrystals, characterized in that Comprising the following steps: (1) Dissolve 3,3-difluorocyclobutylammonium hydrochloride [DFCBA]Cl powder and CuCl2 powder in N,N-dimethylformamide solution respectively, add oleic acid as a ligand solvent, and completely dissolve the mixed reaction as a precursor solution; (2) Rapidly add the precursor solution to the ethyl acetate solution kept in a stirring state until a yellow-green precipitate appears; (3) Separate the supernatant from the lower precipitate, wash and dry the precipitate to obtain the finished product [DFCBA]2CuCl4 nanocrystal powder; (4) Weigh [DFCBA]2CuCl4 nanocrystal powder and disperse it in an ethyl acetate solution containing chloroauric acid and a sacrificial reagent, stir in the dark until adsorption / desorption equilibrium is reached, then use a low-pressure mercury lamp to deposit Au nanoparticles; (5) After the deposition process is complete, centrifuge the solution and wash and dry the precipitate to obtain the finished product Au-[DFCBA]2CuCl4 nanocrystal powder.

2. The method of claim 1, wherein In step (1), the molar ratio of [DFCBA]Cl powder to CuCl2 powder is 2:

1.

3. The method of claim 1, wherein In step (1), unlike the combination of common oleic acid and n-octylamine ligands to restrict the nucleation and formation of nanocrystals, the preparation of [DFCBA]2CuCl4 nanocrystals can only add one kind of ligand, oleic acid, to prevent the reverse decomposition of nanocrystal materials.

4. The method of claim 1, wherein In step (4), 2 mL of isopropanol is added as a sacrificial reagent.

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