Preparation method of lead-free double perovskite nanofiber capable of efficiently photocatalysis CO2 reduction

Abstract

The invention discloses a preparation method of lead-free double perovskite nanofibers capable of efficiently photocatalytic reduction of CO2 at room temperature. The method comprises the following steps: fully dissolving cesium bromide, silver bromide and bismuth bromide in an organic solvent to obtain a precursor solution, adding a ligand and a polymer into the precursor solution, fully magnetically stirring to obtain a spinning solution, and preparing a nanofiber product by utilizing an airflow spinning technology. The airflow spinning technology is creatively adopted to enable the lead-free double perovskite quantum to grow on the nanofiber, a large number of catalytic reaction sites are provided, and the catalytic activity is remarkably improved. According to the method, large-scale preparation of the lead-free double perovskite nanofibers is achieved at the room temperature, controllability and high stability are achieved, operation is easy, the method is suitable for the field of photocatalytic CO2 conversion and the like, and a new thought is provided for sustainable energy development.

Description

Technical Field

[0001] The invention relates to a method for preparing lead-free double perovskite nanofiber capable of efficiently photocatalyzing CO2 reduction, and specifically belongs to the technical field of nanomaterials. Background Art

[0002] As a new type of photocatalytic material, lead-free double perovskite nanofibers have many significant advantages. For example, their unique crystal structure gives them good stability, allowing them to exhibit high activity during the photocatalytic process. Their lead-free properties make them environmentally friendly, avoiding the environmental pollution problems that may be caused by traditional lead-containing materials. Therefore, they have great application potential in the field of photocatalysis, especially in CO2 reduction.

[0003] At present, there are many methods for preparing lead-free double perovskite nanofibers, such as sol-gel method, hydrothermal method and electrospinning method. However, these methods all have some shortcomings. The sol-gel method often requires a complex gelation process, and a slight change in the reaction conditions may have a significant impact on the performance of the product, and the preparation cycle is long; the hydrothermal method has high requirements for the reaction equipment, requiring a specific container that can withstand high temperature and high pressure, and it is difficult to accurately control the reaction conditions during large-scale preparation, resulting in poor product consistency; although the electrospinning method can prepare a nanofiber structure, when preparing lead-free double perovskite nanofibers, its process parameters are complicated to adjust, and the uniformity and crystallinity of the fibers are difficult to achieve the ideal state, and the output is relatively limited. These shortcomings have, to a certain extent, limited the large-scale industrial production of lead-free double perovskite nanofibers and their efficient application in the field of photocatalytic CO2 reduction.

[0004] In view of the many problems existing in the above-mentioned prior art, we urgently need to seek a preparation method for lead-free double perovskite nanofibers that is simple in process, can be industrially manufactured at room temperature, and can efficiently photocatalyze CO2 reduction. Summary of the invention

[0005] In order to improve the existing problems in the preparation process of lead-free double perovskite nanofibers, such as complex and expensive equipment, difficult to accurately control the preparation process, limited output, and the efficiency of photocatalytic CO2 reduction needs to be improved, the present invention mainly discloses a preparation method of lead-free double perovskite nanofibers that can efficiently photocatalytically reduce CO2. The preparation method has a clear raw material ratio, simple operation, mild and easy-to-control reaction conditions, and can realize large-scale production of lead-free double perovskite nanofibers with excellent photocatalytic CO2 reduction performance.

[0006] The present invention discloses a method for preparing lead-free double perovskite nanofibers capable of photocatalytically reducing CO2 efficiently. The lead-free double perovskite nanofibers are prepared based on airflow spinning technology. The photocatalytic reduction of CO2 for 5 hours at room temperature has an average CO production rate of 9 to 66 μmol·g -1 ·h -1 The diameter of the nanofiber product obtained by spinning is 400-500nm, and it shows good photocatalytic performance under the illumination intensity of AM 1.5 xenon lamp.

[0007] The method for preparing a lead-free double perovskite nanofiber capable of highly efficient photocatalytic CO2 reduction according to the present invention comprises the following specific steps:

[0008] Step 1: dissolving cesium bromide (CsBr), silver bromide (AgBr) and bismuth bromide (BiBr3) in an organic mixed solvent to obtain a transparent and uniform lead-free double perovskite precursor solution;

[0009] Step 2: Add the ligand and the polymer to the precursor solution in step 1, and obtain a uniform mixed solution by sufficient magnetic stirring;

[0010] Step 3: Using the mixed solution obtained in step 2 as a spinning solution, airflow spinning technology is used to prepare lead-free double perovskite nanofibers, which are applied to photocatalytic CO2 reduction to produce CO;

[0011] Furthermore, the organic solvent in step 1 is one of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) or a mixed solution of the two solvents;

[0012] Further, the concentration of cesium bromide in the organic solvent in step 1 is 3 to 4 mol / L;

[0013] Further, the concentration of silver bromide in the organic solvent in step 1 is 1.5 to 2 mol / L;

[0014] Further, the concentration of cesium bromide in the organic solvent in step 1 is 1.5 to 2 mol / L;

[0015] Further, the molar ratio of CsBr:AgBr:BiBr3 described in step 1 is 2:1:1;

[0016] Further, the volume ratio of DMSO to DMF in the organic solvent described in step 1 is (0-4):10;

[0017] Further, the ligand described in step 2 is one of oleic acid, oleylamine and n-octylamine;

[0018] Further, the polymer in step 2 is one of polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) or a mixture of the above polymers;

[0019] Further, the volume ratio of the added ligand to the organic solvent in step 2 is (0-1):10;

[0020] Further, the concentration of the polymer in the organic solvent in step 2 is 115 to 150 g / L;

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The present invention provides a method for preparing lead-free double perovskite nanofibers that can efficiently photocatalyze CO2 reduction. The airflow spinning technology is innovatively adopted to realize large-scale continuous production of nanofibers at room temperature. The operating parameters are clear and easy to control with high repeatability, which effectively solves the problems of complex process and difficulty in large-scale production in existing preparation methods.

[0023] 2. The lead-free double perovskite nanofibers prepared by the present invention have excellent performance in photocatalytic CO2 reduction of CO, can efficiently catalyze CO2 to prepare CO, have broad application prospects, and can be widely used in environmental governance, energy conversion and other related fields, providing an effective technical means to solve the problems of greenhouse gas emission reduction and energy regeneration. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a scanning electron microscope image of the Cs2AgBiBr6 / PAN nanofiber prepared in Example 1;

[0025] Figure 2 This is a graph showing the photocatalytic CO2 reduction yield of Cs2AgBiBr6 / PAN nanofibers prepared in Example 1;

[0026] Figure 3 This is a graph showing the photocatalytic CO2 reduction yield of Cs2AgBiBr6 / PAN nanofibers prepared in Example 3;

[0027] Figure 4 The photocatalytic CO2 reduction yield of Cs2AgBiBr6 / PAN nanofibers prepared in Example 5

[0028] Specific implementation examples

[0029] The following is a clear and complete description of the technical solutions in the examples of the present invention. Obviously, the examples described are only part of the examples of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The following experimental methods and detection methods are conventional methods unless otherwise specified; the following reagents and raw materials are commercially available unless otherwise specified.

[0031] Example 1

[0032] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent of 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0033] Step 2: Add 1.5 g of polyacrylonitrile and 0.05 mL of oleylamine to the mixed solution prepared in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0034] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after 5 h of catalysis was 27 μmol·g -1· h -1 .

[0035] Example 2

[0036] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent mixed with 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0037] Step 2: Add 1.5 g of a mixture of polyacrylonitrile and polymethyl methacrylate to the mixed solution prepared in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0038] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after 5 h of catalysis was 10 μmol·g -1· h -1 .

[0039] Example 3

[0040] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent of 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0041] Step 2: Add 1.5 g of polyacrylonitrile and 0.05 mL of n-octylamine to the mixed solution obtained in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0042] The prepared Cs2AgBiBr6 / PAN nanofibers were tested for photocatalytic CO2 reduction. The average CO production rate was 10 μmol·g after 5 h of catalysis. -1 ·h -1 .

[0043] Example 4

[0044] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent of 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0045] Step 2: Add 1.5 g of polyacrylonitrile and 0.1 mL of oleic acid to the mixed solution obtained in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0046] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after 5 h of catalysis was 9 μmol·g -1 ·h -1 .

[0047] Example 5

[0048] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent mixed with 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0049] Step 2: Add 1.5 g of polyacrylonitrile and 0.2 mL of oleic acid to the mixed solution obtained in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0050] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after 5 h of catalysis was 47 μmol·g -1 ·h -1 .

[0051] Example 6

[0052] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent of 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0053] Step 2: Add 1.5 g of polyacrylonitrile and 0.4 mL of oleic acid to the mixed solution obtained in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0054] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after 5 h of catalysis was 66 μmol·g -1 ·h -1 .

[0055] Example 7

[0056] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent of 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0057] Step 2: Add 1.5 g of polyacrylonitrile and 0.6 mL of oleic acid to the mixed solution obtained in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0058] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after catalysis for 5 h was 60 μmol·g -1 ·h -1 .

[0059] Example 8

[0060] Step 1: 0.4 mmol of cesium bromide, 0.2 mmol of silver bromide and 0.2 mmol of bismuth bromide were dissolved in an organic solvent mixed with 3 mL of DMSO and 10 mL of DMF, and a uniform mixed solution was obtained by sufficient magnetic stirring;

[0061] Step 2: Add 1.5 g of polyacrylonitrile and 0.8 mL of oleic acid to the mixed solution obtained in step 1, control the magnetic stirring speed to 1200 r / min, and stir for 6 to 8 hours to obtain a spinning solution;

[0062] The Cs2AgBiBr6 / PAN nanofibers prepared in this experiment were tested for photocatalytic CO2 reduction. The average CO production rate after 5 h of catalysis was 62 μmol·g -1 ·h -1 .

[0063] The above results indicate that the present invention realizes the controllable preparation of lead-free double perovskite nanofibers. By regulating the type and amount of ligands added in Cs2AgBiBr6 / PAN nanofibers, the prepared nanofibers have a higher photocatalytic CO2 reduction ability.

[0064] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for preparing lead-free double perovskite nanofibers capable of efficient photocatalytic CO2 reduction, characterized in that: The following steps are involved: Step 1: Dissolve cesium bromide (CsBr), silver bromide (AgBr) and bismuth bromide (BiBr3) in an organic solvent to obtain a transparent and uniform lead-free double perovskite precursor solution; Step 2: Add the ligand and the polymer to the precursor solution in step 1, and obtain a uniform mixed solution by sufficient magnetic stirring; Step 3: Using the mixed solution obtained in step 2 as the spinning solution, the lead-free double perovskite nanofibers are prepared by air-spinning technology, and applied to the photocatalytic CO2 reduction to produce CO: The organic solvent in step 1 is one of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) or a mixed solution of the two solvents; The concentration of cesium bromide in the organic solvent in step 1 is 3-4 mol / L; The concentration of silver bromide in the organic solvent described in step 1 is 1.5-2 mol / L; The concentration of bismuth bromide in the organic solvent in step 1 is 1.5-2 mol / L; The ligand described in step 2 is one of oleic acid, oleylamine and n-octylamine; The polymer described in step 2 is one of polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) or a mixture of the above polymers.

2. The preparation method according to claim 1, characterized in that The molar ratio of CsBr:AgBr:BiBr3 described in step 1 is 2:1:

1.

3. The preparation method according to claim 1, characterized in that The volume ratio of DMSO to DMF in the organic solvent described in step 1 is (0-4):

10.

4. The preparation method according to claim 1, characterized in that The volume ratio of the added ligand to the organic solvent in step 2 is (0-1):

10.

5. The preparation method according to claim 1, characterized in that The concentration of the polymer in the organic solvent in step 2 is 115-150 g / L.

6. The preparation method according to claim 1, characterized in that The production rate of CO in the lead-free double perovskite nanofiber photocatalytic CO2 reduction process described in step 3 is 9 to 66 μmol·g -1 ·h -1 .

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