Bismuth-antimony-based bromide perovskite material for preparing KA oil through photocatalysis of cyclohexane oxidation as well as preparation method and application of bismuth-antimony-based bromide perovskite material

Abstract

The invention discloses a bismuth-antimony-based bromide perovskite material for preparing KA oil through photocatalysis of cyclohexane oxidation and a preparation method and application of the bismuth-antimony-based bromide perovskite material. The method comprises the following steps that S1, CsBr is added into a round-bottom flask containing acetonitrile and ethyl alcohol, and after ultrasonic treatment is conducted for a period of time, CsBr is evenly dispersed; s2, putting the round-bottom flask in the step S1 into an oil bath pan, and stirring for a period of time at a constant temperature; s3, dissolving BiBr3 and SbBr3 in a mixed solution of acetonitrile and ethanol, and stirring until the BiBr3 and the SbBr3 are completely dissolved to obtain a precursor solution; s4, injecting the precursor solution into the round-bottom flask in the step S2 to generate a precipitate, continuously stirring at constant temperature for a period of time, and cooling to room temperature; s5, transferring the mixed solution into a centrifuge tube by using a rubber head dropper, centrifuging at a certain rotating speed, and removing supernate to obtain yellow precipitate; and repeatedly washing with ethanol for three times, and drying in a vacuum oven for a period of time to obtain the Cs3Sb2-xBixBr9 perovskite particles.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite materials, and in particular relates to a bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane, and a preparation method and application thereof. Background Art

[0002] Selective catalytic oxidation of alkanes into high value-added organic compounds by activating CH bonds has always been an important topic in the fields of medicine and chemical industry. The direct oxidation of cyclohexane is the main way to produce cyclohexanol and cyclohexanone. These two oxidation products are collectively called KA oil, which can be used in pharmaceutical synthesis and is also an important raw material for the production of nylon materials.

[0003] Traditional industrial oxidation of cyclohexane to produce KA oil generally uses homogeneous catalysts such as manganese salts or cobalt salts. Since the CH bond energy of cyclohexane is high and difficult to activate, a harsh high temperature and high pressure environment is required, generally 152-162°C, 10-20atm of oxygen or air environment. The conversion rate of cyclohexanol and cyclohexanone in industrial production is low, about 4-6%, and the selectivity is maintained at 70-85%. At the same time, the activation energy barrier of cyclohexanol and cyclohexanone is lower than that of cyclohexane, and it is easy to over-oxidize to form by-products. Therefore, it is urgent to develop a green, sustainable, fast-conversion, and highly selective method for cyclohexane oxidation to prepare KA oil.

[0004] Photocatalysis is a new type of green catalytic method with mild catalytic conditions. It can convert green and sustainable solar energy into chemical energy, help solve environmental problems and energy crises, and has great research value in the field of catalysis.

[0005] There have been some studies on cyclohexane oxidation using photocatalysis. These studies have used different types of photocatalysts, including hydrocarbons, metals and metal oxides, MOFs and mesoporous silica-supported catalysts. The use of heterogeneous catalysts to oxidize cyclohexane is believed to improve selectivity and minimize catalyst separation costs. Halide perovskites and their derivatives are widely used in heterogeneous catalysis due to their unique photophysical properties, including high light absorption coefficients and easily regulated structures.

[0006] The general structural formula of traditional halide perovskites is ABX3, where the A position is usually Cs + , Li + 、Na + Metal cations or MA + Organic cations such as Pb 2+ ,Ge 2+ Sn 2+ The X position is occupied by a high-valent metal cation, and the X position is occupied by a halogen ion Cl - Br - ,I- In recent years, it has been found that the band gap of halide perovskite materials can be adjusted through component engineering, thereby regulating their catalytic performance. For example, in 2020, Chen et al. systematically studied the addition of Sb to Cs3Bi2I9. 3+ Cs3Bi 2x Sb 2-2x A series of Cs3Bi was prepared by coprecipitation method. 2x Sb 2-2x I9 (x = 0.1, 0.3, 0.5, 0.7, 0.9). It is worth noting that Sb 3+ Doping into Cs3Bi2I9 will reduce its band gap, which in turn helps it absorb long-wavelength light in the visible light range and also promotes the carrier mobility. This excellent optoelectronic property makes Cs3Bi 0.6 Sb 1.4 I9 simulates sunlight at AM 1.5G (100mW cm -2 ) to achieve a hydrogen production rate of 926 μmol g -1 h -1 .

[0007] However, there are few reports on the use of halide perovskites to catalyze the oxidation of cyclohexane to prepare KA oil. Therefore, it is of great significance to obtain a halide perovskite material through the B-site component regulation strategy to achieve efficient and highly selective photocatalytic oxidation of cyclohexane to prepare KA oil. Summary of the invention

[0008] To solve the above problems, the present invention proposes a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil, as well as a preparation method and application thereof. By regulating the composition ratio of antimony ions and bismuth ions at the B position, the bismuth antimony-based bromide perovskite material can achieve efficient and highly selective catalytic cyclohexane oxidation to prepare KA oil under visible light.

[0009] The present invention adopts the following technical solutions:

[0010] A method for preparing a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil comprises the following steps:

[0011] S1. Add CsBr into a round-bottom flask containing a mixed solution of acetonitrile and ethanol, and ultrasonicate for a period of time to make CsBr dispersed evenly;

[0012] S2, placing the round-bottom flask in step S1 in an oil bath at a certain temperature, and stirring at a constant speed for a period of time;

[0013] S3, dissolving a certain proportion of BiBr3 and SbBr3 in a mixed solution of acetonitrile and ethanol, stirring to completely dissolve them, to obtain a precursor solution;

[0014] S4, injecting the precursor solution obtained in step S3 into the round-bottom flask in step S2 at one time to generate precipitation, continuing to stir at a constant temperature for a period of time, and then cooling to room temperature;

[0015] S5. Use a rubber-tipped dropper to transfer the mixed solution into a centrifuge tube, centrifuge at a certain speed, remove the supernatant, and obtain a yellow precipitate; after repeated washing with ethanol three times, place it in a vacuum oven to dry for a period of time, and store it in a cool and dark place to obtain a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil, that is, Cs3Sb 2- x Bi x Br9 perovskite particles.

[0016] Preferably, in step S1, the ultrasonic time is 15 to 25 min, and the volume ratio of acetonitrile to ethanol is 1:4.

[0017] Preferably, in step S2, the temperature of the oil bath is kept constant at 50° C., the stirring speed is 600-800 rpm, and the stirring time is 5 h.

[0018] Preferably, the total amount of BiBr3 and SbBr3 in step S3 is constant at 0.4 mmol, and the molar ratio of the two corresponds to Cs3Sb 2- x Bi x Br9 nanoparticles with different x values.

[0019] Preferably, in step S4, after the precursor solution is injected, stirring is continued at a constant temperature of 50° C. for 45 to 60 minutes.

[0020] Preferably, in step S5, the centrifugal speed is 8000-10000 rpm, and the centrifugal time is 2-5 min; the drying temperature of the vacuum oven is 45-60° C., and the drying time is 7-9 h.

[0021] A bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is prepared by the method for preparing the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane; the chemical formula of the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is Cs3Sb 2-x Bi x Br9, wherein 0≤x≤2, the catalytic activity of the catalyst in catalyzing cyclohexane oxidation is improved by adjusting the doping ratio of bismuth ions.

[0022] Preferably, the doping amount of bismuth ions in the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is 35%, that is, when x=0.7, the chemical formula of the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is Cs3Sb 1.3 Bi 0.7 Br9.

[0023] An application of a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil, wherein the bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil is used as a catalyst for selective photocatalytic cyclohexane oxidation to prepare KA oil, and the catalytic conditions are: the amount of the bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil is 5 mg, the volume of cyclohexane is 5 mL, the temperature of the photocatalytic cyclohexane oxidation reaction is controlled at 25°C, the light source of the photocatalysis is a xenon lamp, and the light intensity is 100 mW cm -2 ~300mW cm -2 .

[0024] After adopting the above technical solution, the present invention has the following advantages compared with the background technology:

[0025] 1. The bismuth antimony-based bromide perovskite material prepared by the present invention for photocatalytic cyclohexane oxidation to prepare KA oil has good crystallinity and chemical stability, a simple preparation method, and low cost, which is conducive to the actual production of the catalyst.

[0026] 2. The present invention develops a new B-site component regulation strategy to realize halide perovskite, which can be applied to the preparation of KA oil by efficient and highly selective photocatalytic cyclohexane oxidation.

[0027] 3. The bismuth ion doping amount in the bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil of the present invention is 35%, that is, when x=0.7, its catalytic activity for cyclohexane oxidation is relatively high while maintaining high selectivity for KA oil, and can be preferably selected. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Different Bi prepared in Examples 1, 2 and 3 of the present invention 2+ Doping ratio of Cs3Sb 1.3 Bi 0.7 Br9, Cs3Sb 1.1 Bi 0.9 Br9 and Cs3Sb 0.9 Bi 1.1 XRD pattern of Br9;

[0029] Figure 2 Different Bi prepared in Examples 1, 2 and 3 of the present invention2+ Doping ratio of Cs3Sb 1.3 Bi 0.7 Br9, Cs3Sb 1.1 Bi 0.9 Br9 and Cs3Sb 0.9 Bi 1.1 Performance comparison of Br9 catalyzed cyclohexane oxidation;

[0030] Figure 3 Different Bi prepared in Examples 1, 2 and 3 of the present invention 2+ Doping ratio of Cs3Sb 1.3 Bi 0.7 Br9, Cs3Sb 1.1 Bi 0.9 Br9 and Cs3Sb 0.9 Bi 1.1 Absorption spectrum of Br9;

[0031] Figure 4 Cs3Sb prepared in Example 1 of the present invention 1.3 Bi 0.7 SEM image of Br9. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] See also Figures 1 to 4 .

[0034] Example 1

[0035] This embodiment provides a bismuth antimony-based bromide perovskite material Cs3Sb 1.3 Bi 0.7 The synthesis method of Br9, the specific steps are as follows:

[0036] S1. Add 0.6 mmol of CsBr into a round-bottom flask containing a mixed solution of 2 mL of acetonitrile and 8 mL of ethanol, and perform ultrasonic treatment for 15 min to make the solution evenly dispersed.

[0037] S2. Place the round-bottom flask in an oil bath at 50°C and 700 rpm, and stir at constant temperature for 5 h to completely dissolve CsBr.

[0038] S3. Dissolve 0.14 mmol of BiBr3 and 0.26 mmol of SbBr3 in a mixed solution of 2 mL of acetonitrile and 8 mL of ethanol, and stir to completely dissolve them to obtain a precursor solution.

[0039] S4. Rapidly inject the precursor solution into the CsBr solution obtained after stirring for 5 hours in the round-bottom flask. A large amount of precipitation is generated. Continue stirring at a constant temperature of 50°C for 1 hour and then cool to room temperature.

[0040] S5. Use a rubber-tipped dropper to transfer the solution into a 50 mL centrifuge tube, centrifuge at 10,000 rpm for 4 min, remove the waste liquid, and obtain a yellow precipitate. After washing with ethanol three times, place it in a vacuum drying oven at 50 ° C for 8 h, and store it in a cool and dark place to obtain a bismuth antimony-based bromide perovskite material Cs3Sb 1.3 Bi 0.7 Br9.

[0041] Example 2

[0042] This embodiment provides a bismuth antimony-based bromide perovskite material Cs3Sb 1.1 Bi 0.9 The synthesis method of Br9, the specific steps are as follows:

[0043] S1. Add 0.6 mmol of CsBr into a round-bottom flask containing a mixed solution of 2 mL of acetonitrile and 8 mL of ethanol, and perform ultrasonic treatment for 15 min to make the solution evenly dispersed.

[0044] S2. Place the round-bottom flask in an oil bath at 50°C and 700 rpm, and stir at constant temperature for 5 h to completely dissolve CsBr.

[0045] S3. Dissolve 0.18 mmol of BiBr3 and 0.22 mmol of SbBr3 in a mixed solution of 2 mL of acetonitrile and 8 mL of ethanol, and stir to completely dissolve them to obtain a precursor solution.

[0046] S4. Rapidly inject the precursor solution into the CsBr solution obtained after stirring for 5 hours in the round-bottom flask. A large amount of precipitation is generated. Continue stirring at a constant temperature of 50°C for 1 hour and then cool to room temperature.

[0047] S5. Use a rubber-tipped dropper to transfer the solution into a 50 mL centrifuge tube, centrifuge at 10,000 rpm for 4 min, remove the waste liquid, and obtain a yellow precipitate. After washing with ethanol three times, place it in a vacuum drying oven at 50 ° C for 8 h, and store it in a cool and dark place to obtain a bismuth antimony-based bromide perovskite material Cs3Sb 1.1 Bi 0.9 Br9.

[0048] Example 3

[0049] This embodiment provides a bismuth antimony-based bromide perovskite material Cs3Sb 0.9 Bi 1.1 The synthesis method of Br9, the specific steps are as follows:

[0050] S1. Add 0.6 mmol of CsBr into a round-bottom flask containing a mixed solution of 2 mL of acetonitrile and 8 mL of ethanol, and perform ultrasonic treatment for 15 min to make the solution evenly dispersed.

[0051] S2. Place the round-bottom flask in an oil bath at 50°C and 700 rpm, and stir at constant temperature for 5 h to completely dissolve CsBr.

[0052] S3. Dissolve 0.22 mmol of BiBr3 and 0.18 mmol of SbBr3 in a mixed solution of 2 mL of acetonitrile and 8 mL of ethanol, and stir to completely dissolve them to obtain a precursor solution.

[0053] S4. Rapidly inject the precursor solution into the CsBr solution obtained after stirring for 5 hours in the round-bottom flask. A large amount of precipitation is generated. Continue stirring at a constant temperature of 50°C for 1 hour and then cool to room temperature.

[0054] S5. Use a rubber-tipped dropper to transfer the solution into a 50 mL centrifuge tube, centrifuge at 10,000 rpm for 4 min, remove the waste liquid, and obtain a yellow precipitate. After washing with ethanol three times, place it in a vacuum drying oven at 50 ° C for 8 h, and store it in a cool and dark place. Obtain bismuth antimony-based bromide perovskite material Cs3Sb 0.9 Bi 1.1 Br9.

[0055] Example 4

[0056] This embodiment provides a bismuth antimony-based bromide perovskite material Cs3Sb 1.3 Bi 0.7 Br9, Cs3Sb 1.1 Bi 0.9 Br9 and Cs3Sb 0.9 Bi 1.1 The catalytic oxidation experiment of cyclohexane with Br9, the specific steps are as follows:

[0057] Weigh 5 mg of Cs3Sb in Example 1 1.3 Bi 0.7 Br9 nanoparticles, Cs3Sb in Example 2 1.1 Bi 0.9 Br9 nanoparticles and Cs3Sb in Example 3 0.9 Bi 1.1 Br9 nanoparticles and 5 mL of cyclohexane were added to the photoreaction tube, which was sealed with a rubber stopper and placed in an air atmosphere. The catalyst was evenly dispersed by ultrasound to form a uniform suspension. The xenon lamp was turned on and the photoreaction tube was placed under the xenon lamp light source while continuously stirring. The light intensity was 300 mW cm -2, stirring speed 600rpm. After 4h of reaction, the reaction solution was taken out and the yields of cyclohexanol and cyclohexanone were determined by gas chromatography. 1.3 Bi 0.7 Br9, Cs3Sb 1.1 Bi 0.9 Br9 and Cs3Sb 0.9 Bi 1.1 The test results of cyclohexane catalytic oxidation of Br9 are as follows Figure 2 shown.

[0058] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil, characterized in that: The steps include: S1. Add CsBr into a round-bottom flask containing a mixed solution of acetonitrile and ethanol, and ultrasonicate for a period of time to make CsBr dispersed evenly; S2, placing the round-bottom flask in step S1 in an oil bath at a certain temperature, and stirring at a constant speed for a period of time; S3, dissolving a certain proportion of BiBr3 and SbBr3 in a mixed solution of acetonitrile and ethanol, stirring to completely dissolve them, to obtain a precursor solution; S4, injecting the precursor solution obtained in step S3 into the round-bottom flask in step S2 at one time to generate precipitation, continuing to stir at a constant temperature for a period of time, and then cooling to room temperature; S5. Use a rubber-tipped dropper to transfer the mixed solution into a centrifuge tube, centrifuge at a certain speed, remove the supernatant, and obtain a yellow precipitate; after repeated washing with ethanol three times, place it in a vacuum oven to dry for a period of time, and store it in a cool and dark place to obtain a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil, that is, Cs3Sb 2-x Bi x Br9 perovskite particles.

2. The method for preparing a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil as claimed in claim 1, characterized in that: In step S1, the ultrasonication time is 15 to 25 min, and the volume ratio of acetonitrile to ethanol is 1:

4.

3. The method for preparing a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil according to claim 1, characterized in that: In step S2, the temperature of the oil bath is kept constant at 50° C., the stirring speed is 600-800 rpm, and the stirring time is 5 h.

4. The method for preparing a bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil as claimed in claim 1, characterized in that: In step S3, the total amount of BiBr3 and SbBr3 is constant at 0.4 mmol, and the molar ratio of the two corresponds to Cs3Sb 2-x Bi x Br9 nanoparticles with different x values.

5. The method for preparing a bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic cyclohexane oxidation according to claim 1, characterized in that: In step S4, after the precursor solution is injected, stirring is continued at a constant temperature of 50° C. for 45 to 60 minutes.

6. The method for preparing a bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic cyclohexane oxidation according to claim 1, characterized in that: In step S5, the centrifugal speed is 8000-10000 rpm, and the centrifugal time is 2-5 min; the drying temperature of the vacuum oven is 45-60° C., and the drying time is 7-9 h.

7. A bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic cyclohexane oxidation, characterized in that: The bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is prepared by the method for preparing bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane as described in any one of claims 1 to 6; the chemical formula of the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is Cs3Sb 2-x Bi x Br9, wherein 0≤x≤2, the catalytic activity of the catalyst in catalyzing cyclohexane oxidation is improved by adjusting the doping ratio of bismuth ions.

8. The bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic cyclohexane oxidation according to claim 7, characterized in that: The doping amount of bismuth ions in the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is 35%, that is, when x=0.7, the chemical formula of the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane is Cs3Sb 1.3 Bi 0.7 Br9.

9. An application of the bismuth antimony-based bromide perovskite material for preparing KA oil by photocatalytic oxidation of cyclohexane as claimed in claim 7, characterized in that: The bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil is used as a catalyst for selective photocatalytic cyclohexane oxidation to prepare KA oil, and the catalytic conditions are: the amount of the bismuth antimony-based bromide perovskite material for photocatalytic cyclohexane oxidation to prepare KA oil is 5 mg, the volume of cyclohexane is 5 mL, the temperature of the photocatalytic cyclohexane oxidation reaction is controlled at 25° C., the light source of the photocatalysis is a xenon lamp, and the light intensity is 100 mW cm -2 ~300mW cm -2 .

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