Application of Zinc gallate ultrathin nanosheets with oxygen vacancies in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals

Abstract

This invention discloses the application of oxygen-vacancy-bearing zinc gallate ultrathin nanosheets in the photocatalytic reduction of sulfur hexafluoride (SF6) to synthesize fluorine-containing organic chemicals. The oxygen-vacancy-bearing zinc gallate ultrathin nanosheets are prepared by the following process: zinc acetate, gallium salt, ethylenediamine, and water are mixed to obtain a mixed solution, which is placed in a hydrothermal reactor and reacted at 180-200°C. After cooling, the solution is calcined in a mixed atmosphere of hydrogen and argon to obtain the oxygen-vacancy-bearing zinc gallate ultrathin nanosheets; the calcination temperature is 400-500°C. This invention uses a simple hydrothermal method to prepare oxygen-vacancy-bearing zinc gallate ultrathin nanosheets. Compared with the original zinc gallate ultrathin nanosheets, the oxygen-vacancy-bearing zinc gallate ultrathin nanosheets exhibit superior photocatalytic reduction performance of SF6, and can photocatalytically reduce SF6 to cyanogen fluoride and 1-fluoropropylene under ambient pressure.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, specifically to the application of an oxygen-vacant zinc gallate ultrathin nanosheet in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals. Background Technology

[0002] Sulfur hexafluoride (SF6) is a colorless, odorless, non-flammable heavy gas with a molecular weight of 146.07. It possesses excellent electrical properties, making it suitable for a wide range of specialized applications in electrical and electronic equipment, industrial processes, scientific fields, and commercial products. Since the mid-1970s, SF6 has been widely used in various applications, including as a gaseous dielectric in electrical and electronic systems such as circuit breakers, high-voltage coaxial cables, gas-insulated substations, and transformers. It is also used as an etching gas in semiconductor manufacturing processes and as a covering / degassing gas in the casting of light metals such as aluminum and magnesium. Furthermore, it serves as a tracer in various scientific studies, helping to analyze air and groundwater flow patterns, detect leaks in underground pipelines, and study the diffusion of air pollutants in the atmosphere. However, it must be noted that SF6 is a potent greenhouse gas with high radioactivity and low water solubility. Its global warming potential (GWP) is 23,500 times that of CO2, meaning that emitting 1 kilogram of SF6 gas produces a greenhouse effect equivalent to emitting 23.5 tons of CO2 gas. Meanwhile, SF6 has an atmospheric lifetime of up to 3200 years, and its impact on global warming is cumulative, potentially causing permanent damage to the atmospheric environment. Under the dual-carbon context, the power industry is actively promoting SF6-free or low-SF6 electrical equipment, and the semiconductor manufacturing industry is gradually using SF6 as a gas substitute, resulting in a large amount of SF6 being decommissioned in the future. Therefore, it is necessary to study a method for disposing of decommissioned and leaked SF6 into the natural world. Thus, the research on the rational design of efficient photocatalysts and the exploration of catalytic conversion of SF6 under mild conditions is urgently needed.

[0003] Patent application JP2000135417A discloses a method for decomposing sulfur hexafluoride. The method involves irradiating sulfur hexafluoride-containing waste gas with light in the presence of a photocatalyst. The photocatalyst includes compounds such as titanium dioxide and zinc oxide, which undergo oxidation upon light irradiation. However, it does not disclose zinc gallate as a catalyst. Furthermore, the patent indicates that sulfur hexafluoride is decomposed into SO₂. x The toxic mixture of gases such as HF and H2 cannot generate fluorinated organic chemicals, thus enabling the value-added utilization of sulfur hexafluoride.

[0004] The paper (Wu Y, He D, Li L, et al. Optimized full CO2 photoreduction process by defective spinel atomic layers[J]. Chemical Communications, 2023, 59(78): 11700-11703.) discloses an optimized full CO2 photoreduction process using defective spinel atomic layers. Oxygen-deficient ZnGa2O4 atomic layers were successfully prepared and validated by electron spin resonance spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption near-edge structure spectroscopy. UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, surface photovoltage spectroscopy, N2 adsorption-desorption isotherms, and density functional theory calculations show that the presence of oxygen defects helps enhance CO2 adsorption and protonation processes. The carbon monoxide release rate of the defective ZnGa2O4 atomic layers is approximately 88 times higher. However, the paper does not provide information on its application in catalyzing sulfur hexafluoride. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to photocatalytically convert sulfur hexafluoride into fluorine-containing organic chemicals.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] The application of oxygen-vacant zinc gallate ultrathin nanosheets in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, wherein the oxygen-vacant zinc gallate ultrathin nanosheets are prepared according to the following process:

[0008] S1. Zinc acetate, gallium salt, ethylenediamine and water are mixed to obtain a mixture; wherein the gallium salt is gallium nitrate or gallium chloride;

[0009] S2. Place the mixture in a hydrothermal reaction apparatus and react at 180-200℃. After cooling, the original zinc gallate ultrathin nanosheets are obtained.

[0010] S3. The original zinc gallate ultrathin nanosheets are calcined in a mixed atmosphere of hydrogen and argon to obtain the zinc gallate ultrathin nanosheets with oxygen vacancies; wherein the calcination temperature is 400-500℃.

[0011] Preferably, in S1, the ratio of zinc acetate, gallium salt, ethylenediamine, and water is 220mg:512mg:10ml:20ml.

[0012] Preferably, in S1, the zinc acetate is zinc acetate dihydrate.

[0013] Preferably, in S1, zinc acetate is dissolved in water, gallium salt is added and stirred, and then ethylenediamine is added to obtain a mixture.

[0014] Preferably, in S2, the reaction time is 24 hours.

[0015] Preferably, in S3, the volume fraction of hydrogen in the hydrogen and argon mixed atmosphere is 5%.

[0016] Preferably, in step S3, the calcination time is 1 hour.

[0017] Preferably, the application of the oxygen-vacancy-bearing zinc gallate ultrathin nanosheets in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals involves using acetonitrile and sulfur hexafluoride as raw materials and the oxygen-vacancy-bearing zinc gallate ultrathin nanosheets as a catalyst to reduce sulfur hexafluoride to cyanogen fluoride and 1-fluoropropylene.

[0018] Preferably, the photocatalytic reduction temperature is 60°C and the time is 10 hours.

[0019] Preferably, in the photocatalytic reduction, the power of the light source is 300W.

[0020] This invention utilizes oxygen-vacancy-bearing zinc gallate ultrathin nanosheets synthesized controllably via a hydrothermal method as a catalyst, which can accelerate the separation of electrons and vacancies and has strong catalytic ability. Under normal pressure and light radiation, using acetonitrile as a reducing agent, the photocatalytic reduction of SF6 to cyanide fluoride and 1-fluoropropylene is highly efficient, stable, environmentally friendly, and sustainable. Attached Figure Description

[0021] Figure 1 The XRD diffraction patterns of the original zinc gallate ultrathin nanosheets (a) and zinc gallate ultrathin nanosheets with oxygen vacancies (b) in Example 2 of the present invention are shown.

[0022] Figure 2 The images shown are transmission electron microscope (TEM) images (A) and high-resolution TEM images (B) of the original zinc gallate ultrathin nanosheets in Example 2 of the present invention, and transmission electron microscope (TEM) images (C) and high-resolution TEM images (D) of the zinc gallate ultrathin nanosheets with oxygen vacancies.

[0023] Figure 3 The X-ray photoelectron spectroscopy (XPS) spectra of the original zinc gallate ultrathin nanosheets (a) and zinc gallate ultrathin nanosheets with oxygen vacancies (b) in Example 2 of this invention are shown.

[0024] Figure 4 The images show the EPR spectra of the original zinc gallate ultrathin nanosheets (gray) and zinc gallate ultrathin nanosheets with oxygen vacancies (black) in Example 2 of this invention.

[0025] Figure 5 This is the original NMR spectrum of the photocatalytic reduction of SF6 by zinc gallate ultrathin nanosheets in Example 2 of this invention;

[0026] Figure 6 The image shows the NMR spectrum of the photocatalytic reduction of SF6 by ultrathin zinc gallate nanosheets with oxygen vacancies prepared in Example 2 of this invention.

[0027] Figure 7 The transmission electron microscope (a) and XRD diffraction pattern (b) of the product of Comparative Example 1 of the present invention are shown.

[0028] Figure 8 The EPR spectrum of the product of Comparative Example 2 of this invention is shown below.

[0029] Figure 9 The transmission electron microscope (a) and XRD diffraction pattern (b) of the product of Comparative Example 3 of the present invention are shown.

[0030] Figure 10 The image shows the liquid-phase NMR spectrum of the product prepared in Comparative Example 2 of this invention for the photocatalytic reduction of SF6.

[0031] Figure 11 Transmission electron microscope (a) and XRD diffraction pattern (b) of the zinc gallate ultrathin nanosheets with oxygen vacancies prepared in Example 4 of the present invention.

[0032] Figure 12 Transmission electron microscope (a) and XRD diffraction pattern (b) of the zinc gallate ultrathin nanosheets with oxygen vacancies prepared in Example 5 of the present invention.

[0033] Figure 13 The images show transmission electron microscopy (a) and XRD diffraction pattern (b) of the zinc gallate ultrathin nanosheets with oxygen vacancies prepared in Example 6 of this invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0035] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0036] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0037] Example 1

[0038] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of Ga(NO3)3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 180 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h. The resulting powder was the original zinc gallate ultrathin nanosheets, which were stored in a desiccator for later use.

[0039] Example 2

[0040] A method for preparing ultrathin zinc gallate nanosheets with oxygen vacancies includes the following steps:

[0041] The original zinc gallate ultrathin nanosheets obtained in Example 1 were calcined at 400°C for 1 hour in an H2 / Ar mixed atmosphere with a volume fraction of 5% H2. The resulting powder is the zinc gallate ultrathin nanosheet with oxygen vacancies, which was stored in a desiccator for later use.

[0042] The structure of the prepared compound was identified, and the results are shown in the figure. Figures 1-4 ,Depend on Figure 1 It can be seen that the synthesized phase is pure; Figure 2 This indicates that the synthesized material is an ultrathin two-dimensional nanosheet with a lattice spacing of 0.295 nm. Figure 3 The results show that the product calcined in an H2-Ar mixed atmosphere has more oxygen vacancies than the original uncalcined nanosheets. Figure 4 The ERP further confirms the existence of oxygen vacancies in the calcined product.

[0043] Comparative Example 1

[0044] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of Ga(NO3)3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 160 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h to obtain a powder. Figure 7 This indicates that the obtained powder phase is impure and is not the original zinc gallate ultrathin nanosheet.

[0045] Comparative Example 2

[0046] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of Ga(NO3)3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 180 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h. The resulting powder was the original zinc gallate ultrathin nanosheets. The obtained original zinc gallate ultrathin nanosheets were calcined at 400 °C for 1 h in an O2 atmosphere. Figure 8 This indicates that the obtained powder is not zinc gallate ultrathin nanosheets with oxygen vacancies.

[0047] Comparative Example 3

[0048] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of Ga(NO3)3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 180 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h. The resulting powder was the original zinc gallate ultrathin nanosheets. These original zinc gallate ultrathin nanosheets were calcined at 700 °C for 1 h in an H2 / Ar mixed atmosphere with a H2 volume fraction of 5%. Figure 9 This indicates that the obtained powder is not zinc gallate ultrathin nanosheets with oxygen vacancies, but a mixture of zinc gallate and gallium oxide.

[0049] Example 3

[0050] Examples of photocatalytic reduction of SF6 to cyanide fluoride and 1-fluoropropene using ultrathin zinc gallate nanosheets with oxygen vacancies:

[0051] 10 mg of zinc gallate ultrathin nanosheets with oxygen vacancies prepared in Example 2 were uniformly dispersed on a glass slide and placed in a sealed glass instrument. 8 mL of acetonitrile was injected into the container, followed by the addition of 99.999% pure SF6 and subsequent vacuuming. This process of adding 99.999% pure SF6 and then vacuuming was repeated three times. Sulfur hexafluoride was then added. A 300W xenon lamp was used to simulate sunlight as the light source for the reaction. After reacting at 60°C for 10 hours, a certain amount of cyanogen fluoride and 1-fluoropropylene were obtained.

[0052] Following the method described above, the zinc gallate ultrathin nanosheets with oxygen vacancies prepared in Example 2 were replaced with the original zinc gallate ultrathin nanosheets prepared in Example 1 or the product of Comparative Example 2, uniformly dispersed on a glass slide, with other reaction conditions remaining unchanged, for photocatalytic reduction of SF6. Figure 5 and Figure 6It can be seen that -131.5 belongs to -156 locations belong to Based on the strength, it can be seen that the zinc gallate ultrathin nanosheets with oxygen vacancies prepared in Example 2 yielded more product; from Figure 10 It can be seen that no product is produced when the product of Comparative Example 2 is used as a catalyst.

[0053] When DMF and dichloromethane were used to replace acetonitrile in the above reaction, no product was produced in the liquid phase.

[0054] Example 4

[0055] A method for preparing ultrathin zinc gallate nanosheets with oxygen vacancies includes the following steps:

[0056] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of GaCl3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 180 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h. The resulting powder was the original zinc gallate ultrathin nanosheets. These original zinc gallate ultrathin nanosheets were calcined at 400 °C for 1 h in a 5% (v / v) H2 / Ar mixed atmosphere to obtain the powder containing oxygen vacancies in the zinc gallate ultrathin nanosheets. The transmission electron microscopy (TEM) image and XRD diffraction pattern are shown below. Figure 11 As shown, store it in a desiccator for later use.

[0057] Example 5

[0058] A method for preparing ultrathin zinc gallate nanosheets with oxygen vacancies includes the following steps:

[0059] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of Ga(NO3)3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 180 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h. The resulting powder was the original zinc gallate ultrathin nanosheets. These original zinc gallate ultrathin nanosheets were calcined at 500 °C for 1 h in a 5% (v / v) H2 / Ar mixed atmosphere to obtain the powder containing oxygen vacancies in the zinc gallate ultrathin nanosheets. The transmission electron microscopy (TEM) image and XRD diffraction pattern are shown below. Figure 12 As shown, store it in a desiccator for later use.

[0060] Example 6

[0061] A method for preparing ultrathin zinc gallate nanosheets with oxygen vacancies includes the following steps:

[0062] 220 mg of Zn(CH3COO)2·2H2O was dissolved in 20 mL of deionized water, then 512 mg of Ga(NO3)3 was added and stirred for 20 min. Next, 10 mL of ethylenediamine was added and stirred for 10 min. The liquid was then transferred to a 50 mL polytetrafluoroethylene-lined high-temperature reactor and heated at 200 °C for 24 h, followed by natural cooling to room temperature. The precursor was then washed with ethanol and water to obtain a white precursor, which was then vacuum dried for 12 h. The resulting powder was the original zinc gallate ultrathin nanosheets. These original zinc gallate ultrathin nanosheets were calcined at 400 °C for 1 h in a 5% (v / v) H2 / Ar mixed atmosphere to obtain the powder containing oxygen vacancies in the zinc gallate ultrathin nanosheets. The transmission electron microscopy (TEM) image and XRD diffraction pattern are shown below. Figure 13 As shown, store it in a desiccator for later use.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of an oxygen-vacant zinc gallate ultrathin nanosheet in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: Using acetonitrile and sulfur hexafluoride as raw materials, and the oxygen-vacant zinc gallate ultrathin nanosheets as catalysts, sulfur hexafluoride is reduced to cyanogen fluoride and 1-fluoropropylene. ; The zinc gallate ultrathin nanosheets with oxygen vacancies are prepared according to the following process: S1. Zinc acetate, gallium salt, ethylenediamine and water are mixed to obtain a mixture; wherein the gallium salt is gallium nitrate or gallium chloride; S2. Place the mixture in a hydrothermal reaction apparatus and react at 180-200℃. After cooling, the original zinc gallate ultrathin nanosheets are obtained. S3. The original zinc gallate ultrathin nanosheets are calcined in a mixed atmosphere of hydrogen and argon to obtain the zinc gallate ultrathin nanosheets with oxygen vacancies; wherein the calcination temperature is 400-500℃.

2. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In S1, the ratio of zinc acetate, gallium salt, ethylenediamine, and water is 220mg:512mg:10ml:20ml.

3. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In S1, the zinc acetate is zinc acetate dihydrate.

4. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In S1, zinc acetate is dissolved in water, gallium salt is added and stirred, and then ethylenediamine is added to obtain a mixture.

5. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In S2, the reaction time is 24 hours.

6. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In S3, the volume fraction of hydrogen in the hydrogen and argon mixed atmosphere is 5%.

7. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In S3, the calcination time is 1 hour.

8. The application of the oxygen-vacant zinc gallate ultrathin nanosheets according to claim 1 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: The photocatalytic reduction was carried out at a temperature of 60℃ for 10 hours.

9. The application of zinc gallate ultrathin nanosheets with oxygen vacancies according to any one of claims 1-8 in the photocatalytic reduction of sulfur hexafluoride to synthesize fluorine-containing organic chemicals, characterized in that: In photocatalytic reduction, the power of the light source is 300W.

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