A one-step efficient synthesis of Sn 24 P 19.3 Preparation method of I8 catalyst

Abstract

The invention belongs to the technical field of new phosphorus chemical materials and relates to a one-step efficient synthesis of Sn 24 P 19.3 Preparation method of I8 catalyst. The present invention uses red phosphorus, tin and iodine as raw materials, controls the multi-stage temperature rise and fall cycle heat treatment program, and directly synthesizes high-purity Sn in one step reaction. 24 P 19.3 I8 catalyst and one-step synthesis of supported Sn with promoter 24 P 19.3 I8 catalyst realizes efficient, low-cost and environmentally friendly synthesis of catalysts, greatly improves the preparation scale and efficiency of catalysts, reduces energy consumption and environmental impact in the production process, and the prepared catalyst shows extremely high catalytic activity and stability in the black phosphorus preparation process, laying a solid foundation for the low-cost and large-scale preparation of black phosphorus, and also provides a raw material basis for the preparation and development of other new elemental phosphorus.

Description

Technical Field

[0001] The present invention relates to the technical field of new phosphorus chemical materials, and in particular to a one-step efficient synthesis of Sn 24 P 19.3 Preparation method of I8 catalyst. Background Art

[0002] As a conceptually new two-dimensional layered material, black phosphorus has good application prospects in semiconductors, electrochemistry, solar cells, photocatalysis, flame retardancy, biomedicine and other fields due to its unique structure and excellent physical and chemical properties, such as large specific surface area, high anisotropy, wide light absorption, and high carrier mobility. At present, many methods for preparing black phosphorus have been developed, such as high pressure method, mechanical ball milling method, solvothermal method, bismuth melting method, mercury reflux method and mineralization method. Among them, the mineralization method (i.e., catalytic method) is the most promising method for large-scale and efficient preparation of black phosphorus.

[0003] However, the efficient preparation of the mineralization method is limited by the preparation efficiency and catalytic performance of its main catalyst. The existing technology for large-scale production of black phosphorus based on the mineralization method usually involves mixing the phosphorus source, catalyst (Sn, Pb, In, Bi, etc.) and transport agent (I2, SnI2, SnI4, PbI2, etc.) and then heating the reaction to prepare black phosphorus. Although this production method is easy to operate, it is easy to cause material compaction in industrial-scale production, reduce the conversion rate of the material, and affect the purity of the product. A large number of studies have shown that in the process of preparing black phosphorus assisted by the P-Sn-I system, Sn will be formed. 24 P 19.3 I8 ternary complex and plays a catalytic role, using Sn 24 P 19.3 I8 catalyst, through the production method of separating raw materials and catalyst, can significantly improve the purity of black phosphorus products.

[0004] Existing preparation of Sn 24 P 19.3 The I8 catalyst method usually uses red phosphorus, tin powder and tin tetraiodide as raw materials. Tin tetraiodide is used as Sn 24 P 19.3 The key precursor material in the preparation process of I8 has a complex preparation process, is time-consuming, inefficient, and involves environmentally unfriendly solvents (such as toluene) with high losses. These problems lead to the 24 P 19.3 The high preparation cost of I8 catalyst also limits its large-scale production, which in turn hinders the efficient preparation of catalyst. 24 P 19.3The I8 catalyst method is often prone to sintering and decomposition when preparing black phosphorus at high temperature, which reduces the catalytic activity and stability of the catalyst and is not conducive to the large-scale preparation of black phosphorus. Although patent CN113559886A discloses a method for preparing an efficient synthetic black phosphorus catalyst, which is a method for preparing a catalyst containing an additive by mixing phosphorus iodine tin powder and carbon material additives, grinding, extrusion molding and high-temperature treatment, this preparation method is cumbersome and requires the use of SnI4 to prepare Sn 24 P 19.3 The I8 catalyst is then combined with a carbon additive for a second time, which is time-consuming and inefficient to prepare, greatly limiting the efficiency of catalyst preparation. Summary of the invention

[0005] The purpose of the present invention is to provide a one-step efficient synthesis of Sn 24 P 19.3 The preparation method of I8 catalyst uses red phosphorus, tin and iodine as raw materials to directly synthesize high-purity Sn through a one-step reaction. 24 P 19.3 I8 catalyst and one-step synthesis of supported Sn with promoter 24 P 19.3 I8 catalyst realizes efficient, low-cost and environmentally friendly synthesis of catalysts to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a one-step method for synthesizing Sn 24 P 19.3 I8 catalyst method, the steps comprising: uniformly mixing red phosphorus and tin powder to obtain a phosphorus-tin mixture;

[0008] Iodine and the phosphorus-tin mixture are loaded layer by layer in the order of filling the iodine-phosphorus-tin mixture, and the Sn is obtained after multiple heating and cooling treatments. 24 P 19.3 I8 catalyst.

[0009] Furthermore, the amounts of tin powder, red phosphorus and iodine are as follows: 24 P 19.3 The molar ratio of elements in I8 is used for preparation.

[0010] Furthermore, the number of layers of the layer-by-layer loading is not less than 4 layers, that is, the iodine-phosphorus tin mixture is used as a repeating unit, and there are at least two units.

[0011] Furthermore, the multiple temperature rise and fall treatments are performed no less than twice.

[0012] Furthermore, the procedure of the temperature rise and fall treatment is: heating to 550°C at a heating rate of 5-20°C / min, keeping warm for not less than 20 minutes, then cooling to 500°C at a cooling rate of 0.2-0.5°C / min, keeping warm for not less than 20 minutes.

[0013] The second technical solution of the present invention is to provide a Sn prepared by the above method. 24 P 19.3 I8 catalyst.

[0014] Technical solution 3 of the present invention: providing a one-step method for synthesizing supported Sn 24 P 19.3 I8 catalyst method, the steps comprising:

[0015] The additive, red phosphorus and tin powder are uniformly mixed to obtain a phosphorus-tin additive mixture;

[0016] The iodine and the phosphorus-tin auxiliary agent mixture are loaded layer by layer according to the filling order of the iodine-phosphorus-tin auxiliary agent mixture, and the loaded Sn is obtained after multiple temperature rise and fall treatments. 24 P 19.3 I8 catalyst;

[0017] The auxiliary agent includes at least one of graphite, graphene, carbon nanotubes, expanded graphite, porous carbon, amorphous carbon, Super P, acetylene black, Ketjen black, reduced graphene oxide and graphene oxide.

[0018] Furthermore, the amounts of tin powder, red phosphorus and iodine are as follows: 24 P 19.3 The molar ratio of elements in I8 is used for preparation.

[0019] Furthermore, the load Sn 24 P 19.3 Sn in I8 catalyst 24 P 19.3 The mass ratio of I8 to additives is 5:1-5.

[0020] Furthermore, the number of layers of the layer-by-layer loading is not less than 4 layers, that is, the iodine-phosphorus tin additive mixture is used as a repeating unit, and there are at least two units.

[0021] Furthermore, the multiple temperature rise and fall treatments are performed no less than twice.

[0022] Furthermore, the procedure of the temperature rise and fall treatment is: heating to 550°C at a heating rate of 5-20°C / min, keeping warm for not less than 20 minutes, then cooling to 500°C at a cooling rate of 0.2-0.5°C / min, keeping warm for not less than 20 minutes.

[0023] Technical solution 4 of the present invention: providing a supported Sn prepared by the above method 24 P 19.3 I8 catalyst.

[0024] Technical solution 5 of the present invention: providing a Sn 24 P 19.3 I8 catalyst or supported Sn 24 P 19.3 Application of I8 catalyst in the preparation of black phosphorus.

[0025] Technical solution 6 of the present invention: Provide a method for improving the conversion rate of preparing black phosphorus, using the above Sn 24 P 19.3 I8 catalyst or supported Sn 24 P 19.3 I8 catalyst catalyzes the preparation of black phosphorus.

[0026] The present invention discloses the following technical effects:

[0027] The preparation method of the present invention not only significantly improves Sn 24 P 19.3 The preparation efficiency and scale of the I8 catalyst simultaneously reduced the energy consumption and environmental impact during the production process, and improved the catalytic activity and stability of the catalyst, which is of great significance for promoting the large-scale and efficient preparation of black phosphorus.

[0028] The present invention simplifies the preparation process of the catalyst, improves the preparation efficiency and scale of the catalyst, and at the same time enhances the catalytic performance of the catalyst. This is of great significance for promoting the large-scale production of black phosphorus and developing the application potential of black phosphorus, and also lays the foundation for the development of more new elemental phosphorus catalysts.

[0029] The present invention is a method for efficiently preparing Sn 24 P 19.3 The new method of I8 catalyst directly uses red phosphorus, tin and iodine as raw materials, effectively avoiding the existing preparation of Sn 24 P 19.3 The complex preparation process and environmental risks brought by using tin tetraiodide as a raw material in the I8 catalyst technology. The layered filling method solves the problems of the violent heat release caused by the direct mixing of tin and iodine, and the presence of tin impurities in the product due to the consumption of a large amount of iodine raw materials, which affects the purity of the product. This filling method improves the preparation efficiency of the catalyst and the yield and purity of the catalyst. This filling method can efficiently synthesize Sn in one step. 24 P 19.3 I8 catalyst or supported Sn 24 P 19.3The I8 catalyst not only significantly improves the catalyst preparation yield and greatly shortens the preparation cycle. At the same time, the multi-stage heating and cooling heat treatment method makes the reaction more complete, which is conducive to the preparation of Sn with excellent yield and purity. 24 P 19.3 I8 catalyst or supported Sn 24 P 19.3 I8 catalyst.

[0030] The present invention prepares Sn 24 P 19.3 I8 catalyst or supported Sn 24 P 19.3 The I8 catalyst method helps to improve the production efficiency of the catalyst and the feasibility of large-scale preparation, accelerate the research and development and industrialization process of black phosphorus and other elemental phosphorus, and promote the market promotion and industrialization development of new phosphorus chemical materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 Schematic diagram of the filler and the product of Example 1, wherein (a) is a schematic diagram of the filler, and (b) is a product;

[0033] Figure 2 The Sn prepared in Example 1 24 P 19.3 XRD pattern of I8 catalyst;

[0034] Figure 3 The scanning electron microscope image and element distribution map of the product prepared in Example 1, wherein a and b are scanning electron microscope images, and c, d and e are element distribution maps;

[0035] Figure 4 The XRD spectra of the products of Example 1 and Example 2 are compared;

[0036] Figure 5 The scanning electron microscope image and element distribution map of the product prepared in Example 2, wherein a and b are scanning electron microscope images, and c, d, e and f are element distribution maps;

[0037] Figure 6 Comparison of the yields of black phosphorus prepared by the catalysts prepared in Examples 1 to 2 and Comparative Example 1, and the states of the catalysts before and after catalysis. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0040] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0041] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0042] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0043] The materials and reagents used in the specific embodiments of the present invention are all commercially available products.

[0044] Example 1

[0045] One-step preparation of Sn 24 P 19.3 The steps of I8 catalyst are:

[0046] S1. Weigh 9.100 g iodine, 25.540 g tin powder and 5.360 g red phosphorus for later use;

[0047] S2, red phosphorus and tin powder are mixed and ground evenly to obtain a phosphorus-tin mixture;

[0048] S3, placing half of the iodine in a quartz tube, then adding half of the phosphorus-tin mixture, adding the remaining iodine on the phosphorus-tin mixture, and then adding the remaining phosphorus-tin mixture, stacking into four layers, encapsulating with a quartz column, and then placing in a stainless steel high-temperature and high-pressure reactor for sealing;

[0049] S4. The sealed reactor was heated to 550°C at 5°C / min, kept at this temperature for 30 min, then cooled to 500°C after 225 min and kept at this temperature for 30 min. The above heating and cooling procedures were repeated 6 times, and cooled to room temperature to obtain 38.01 g of Sn. 24 P 19.3 I8 catalyst, conversion rate is 95%.

[0050] Figure 1 The diagram of the packing and the product of Example 1, wherein (a) is the diagram of the packing, and (b) is the product. The iodine and phosphorus-tin mixture is packed in layers to avoid the violent reaction between the sublimated iodine and tin during loading, which releases a large amount of heat and affects the reaction, thereby affecting the yield of the catalyst.

[0051] Figure 2 The Sn prepared in Example 1 24 P 19.3 XRD pattern of I8 catalyst, Figure 2 It can be seen that Sn is observed at 29.3°, 30.5°, 33.7°, 41.7°, and 49.9° 24 P 19.3 The diffraction peaks of the I8 catalyst correspond to crystal planes (320), (321), (410), (430) and (600), indicating that the catalyst was successfully prepared with high purity and no impurities.

[0052] Figure 3 The Sn prepared in Example 1 24 P 19.3 Scanning electron microscope images and element distribution diagrams of I8 catalyst, where a and b are scanning electron microscope images, and c, d and e are element distribution diagrams. Figure 3 It can be seen that the element is distributed relatively evenly, which is beneficial to the stability of the material during use and indicates that the material was successfully synthesized.

[0053] Example 2

[0054] One-step preparation of supported Sn 24 P 19.3 The steps of I8 catalyst are:

[0055] S1. Weigh 9.100 g iodine, 25.540 g tin powder, 5.360 g red phosphorus and 8 g graphite for later use;

[0056] S2, graphite, red phosphorus and tin powder are mixed and ground evenly to obtain a phosphorus-tin additive mixture;

[0057] S3, placing half of the iodine in a quartz tube, then adding half of the phosphorus-tin additive mixture, adding the remaining iodine on the phosphorus-tin additive mixture, and then adding the remaining phosphorus-tin mixture, stacking into four layers, encapsulating with a quartz column, and then placing in a stainless steel high-temperature and high-pressure reactor for sealing;

[0058] S4, the sealed reactor was heated to 550°C at 5°C / min, kept warm for 30 min, cooled to 500°C after 225 min and kept warm for 30 min, the above heating and cooling procedures were repeated 6 times, and cooled to room temperature to obtain 45.33 g of supported Sn containing graphite additive. 24 P 19.3 I8 catalyst, the conversion rate was 94.4%.

[0059] Figure 4 The XRD spectra of the products of Example 1 and Example 2 are compared. Figure 4 It can be seen that Sn is observed at 29.3°, 30.5°, 33.7°, 41.7°, and 49.9° 24 P 19.3 The diffraction peaks of the I8 catalyst are (320), (321), (410), (430) and (600) for the crystal planes. In addition, the diffraction peak at 26.3° corresponds to the (002) crystal plane of carbon, indicating that the supported Sn with the additive was successfully synthesized in one step. 24 P 19.3 I8 catalyst, the addition of additives has no effect on Sn 24 P 19.3 Synthesis of I8 catalyst.

[0060] Figure 5 The scanning electron microscope image and element distribution map of the product prepared in Example 2, wherein a and b are scanning electron microscope images, and c, d, e and f are element distribution maps. Figure 5 It can be seen that the element is distributed relatively evenly, which is beneficial to the stability of the material during use and indicates that the material was successfully synthesized.

[0061] Example 3

[0062] One-step preparation of Sn 24 P 19.3 The steps of I8 catalyst are:

[0063] S1. Weigh 22.750 g iodine, 63.850 g tin powder and 13.400 g red phosphorus for later use;

[0064] S2, red phosphorus and tin powder are mixed and ground evenly to obtain a phosphorus-tin mixture;

[0065] S3, the iodine and phosphorus tin mixture is divided into 5 parts respectively, added into quartz tubes in sequence, stacked into ten layers, packaged with quartz columns, and then placed into a stainless steel high temperature and high pressure reactor for sealing;

[0066] S4. The sealed reactor was heated to 550°C at 5°C / min, kept at this temperature for 30 min, then cooled to 500°C after 225 min and kept at this temperature for 30 min. The above heating and cooling procedures were repeated 6 times, and cooled to room temperature to obtain 97.89 g of Sn. 24 P 19.3 I8 catalyst, the conversion rate is 97.89%.

[0067] Example 4

[0068] One-step preparation of supported Sn 24 P 19.3 The steps of I8 catalyst are:

[0069] S1. Weigh 9.100 g iodine, 25.540 g tin powder, 5.360 g red phosphorus and 8 g carbon nanotubes for later use;

[0070] S2, carbon nanotubes, red phosphorus and tin powder are mixed and ground evenly to obtain a phosphorus-tin additive mixture;

[0071] S3, placing half of the iodine in a quartz tube, then adding half of the phosphorus-tin additive mixture, adding the remaining iodine on the phosphorus-tin additive mixture, and then adding the remaining phosphorus-tin mixture, stacking into four layers, encapsulating with a quartz column, and then placing in a stainless steel high-temperature and high-pressure reactor for sealing;

[0072] S4, heat the sealed reactor, raise the temperature to 550°C at 5°C / min, keep it at that temperature for 30min, then cool it to 500°C after 225min and keep it at that temperature for 30min, repeat the above heating and cooling procedure 6 times, and cool it to room temperature to obtain the supported Sn containing carbon nanotube additive. 24 P 19.3 I8 catalyst.

[0073] Example 5

[0074] One-step preparation of supported Sn 24 P 19.3 The steps of I8 catalyst are:

[0075] S1. Weigh 9.100 g iodine, 25.540 g tin powder, 5.360 g red phosphorus and 8 g graphene for later use;

[0076] S2, graphene, red phosphorus and tin powder are mixed and ground evenly to obtain a phosphorus-tin additive mixture;

[0077] S3, put half of the iodine in the quartz tube, then add half of the phosphorus-tin additive mixture, and add the remaining iodine to the phosphorus-tin additive.

[0078] The remaining phosphorus-tin mixture is added to the mixture, and the mixture is stacked into four layers, which are encapsulated with quartz columns and then placed in a stainless steel high-temperature and high-pressure reactor for sealing;

[0079] S4, heat the sealed reactor, raise the temperature to 550°C at 5°C / min, keep it warm for 30min, cool it to 500°C after 225min and keep it warm for 30min, repeat the above heating and cooling procedure 6 times, and cool it to room temperature to obtain the supported Sn containing graphene additive 24 P 19.3 I8 catalyst.

[0080] Example 6

[0081] One-step preparation of supported Sn 24 P 19.3 The steps of I8 catalyst are:

[0082] S1. Weigh 9.100 g iodine, 25.540 g tin powder, 5.360 g red phosphorus and 8 g porous carbon for later use;

[0083] S2, porous carbon, red phosphorus and tin powder are mixed and ground evenly to obtain a phosphorus-tin additive mixture;

[0084] S3, put half of the iodine in the quartz tube, then add half of the phosphorus-tin additive mixture, and add the remaining iodine to the phosphorus-tin additive.

[0085] The remaining phosphorus-tin mixture is added to the mixture, and the mixture is stacked into four layers, which are encapsulated with quartz columns and then placed in a stainless steel high-temperature and high-pressure reactor for sealing;

[0086] S4, the sealed reactor was heated to 550°C at 5°C / min, kept at this temperature for 30min, then cooled to 500°C after 225min and kept at this temperature for 30min, the above heating and cooling procedures were repeated 6 times, and then cooled to room temperature to obtain a supported Sn containing porous carbon additive. 24 P 19.3 I8 catalyst.

[0087] Comparative Example 1

[0088] Two-step preparation of Sn 24 P 19.3 The steps of I8 catalyst are:

[0089] First, tin tetraiodide is prepared, and then Sn is further prepared. 24 P 19.3 I8 catalyst, the specific steps are as follows:

[0090] S1. Weigh 16.0 g of iodine and 4.8 g of tin into a round-bottom flask, and then pour in 70-100 ml of toluene;

[0091] S2. Build a condensation reflux device and heat the round-bottom flask to 115°C in an oil bath to allow toluene to evaporate, condense and reflux continuously until the toluene solution changes from purple-red to orange-red. The entire reaction process needs to last for 3 hours. After the reaction is completed, the iodine-containing toluene solution will be converted into a toluene solution containing tin tetraiodide;

[0092] S3, build a suction filtration device, and after the reaction is completed, perform hot suction filtration on the toluene solution containing tin tetraiodide to separate the unreacted tin powder;

[0093] S4, placing the filtered toluene solution in a beaker and placing it in a fume hood, and obtaining tin tetraiodide crystals after the toluene is completely evaporated;

[0094] S5, weighing 4.08g of red phosphorus, 7.51g of tin tetraiodide and 15.66g of tin powder respectively, and grinding them in a mortar to reduce the particle size while achieving uniform mixing of the raw materials;

[0095] S6. Divide the ground powder into two parts and seal them in two vacuum quartz tubes (the inner diameter of the quartz tube is 18 mm, the wall thickness is 2 mm, and the tube is sealed at a length of 120 mm);

[0096] S7, placing the quartz tube in a muffle furnace for reaction, firstly raising the temperature from room temperature to 550°C at a rate of 5°C / min, keeping the temperature at 550°C for 30min, then cooling to 500°C within 225min and keeping the temperature for 30min, and then raising the temperature to 550°C within 10min after keeping the temperature, and the process is repeated 7 times before terminating the program and cooling naturally to room temperature;

[0097] S8. After the reaction is completed, take out the tin iodide phosphate block in the quartz tube, grind it into powder, and then sieve it to 200 mesh powder.

[0098] Figure 6 The yield comparison of the catalysts prepared in Examples 1 to 2 and Comparative Example 1 after catalyzing the preparation of black phosphorus and the state of the catalysts before and after catalysis are shown. Figure 5 It can be seen that the catalysts prepared in Examples 1 and 2 of the present invention have high catalytic activity, and the yield of preparing black phosphorus reaches more than 93%. 24 P 19.3 The I8 catalyst did not sinter, which proved that the catalyst had high thermal stability in preparing black phosphorus at high temperature. However, the yield of black phosphorus prepared in Comparative Example 1 was only 84%, and the catalyst was sintered after one use, showing poor stability.

[0099] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. One-step synthesis of Sn 24 P 19.3 I8 catalyst method, characterized in that the steps include: The red phosphorus and the tin powder are uniformly mixed to obtain a phosphorus-tin mixture; Iodine and the phosphorus-tin mixture are loaded layer by layer in the order of the filling material of the iodine-phosphorus-tin mixture, and the Sn is obtained after multiple heating and cooling treatments. 24 P 19.3 I8 catalyst; The amounts of tin powder, red phosphorus and iodine are as follows: 24 P 19.3 The molar ratio of the elements in I8 is prepared; the number of layers of the layer-by-layer loading is not less than 4 layers; The multiple heating and cooling treatments are performed at least twice; the procedure of the heating and cooling treatments is: heating to 550°C at a heating rate of 5 to 20°C / min, keeping the temperature at that temperature for at least 20 minutes, then cooling to 500°C at a cooling rate of 0.2 to 0.5°C / min, and keeping the temperature at that temperature for at least 20 minutes.

2. Sn prepared by the method as claimed in claim 1 24 P 19.3 I8 catalyst.

3. One-step synthesis of supported Sn 24 P 19.3 I8 catalyst method, characterized in that the steps include: The additive, red phosphorus and tin powder are uniformly mixed to obtain a phosphorus-tin additive mixture; The iodine and the phosphorus-tin auxiliary agent mixture are loaded layer by layer according to the filling order of the iodine-phosphorus-tin auxiliary agent mixture, and the loaded Sn is obtained after multiple temperature rise and fall treatments. 24 P 19.3 I8 catalyst; The auxiliary agent includes at least one of graphite, graphene, carbon nanotubes, expanded graphite, porous carbon, amorphous carbon, SuperP, acetylene black, Ketjen black, reduced graphene oxide and graphene oxide; The amounts of tin powder, red phosphorus and iodine are as follows: 24 P 19.3 The molar ratio of the elements in I8 is prepared; the number of layers of the layer-by-layer loading is not less than 4 layers; the supported Sn 24 P 19.3 Sn in I8 catalyst 24 P 19.3 The mass ratio of I8 to additives is 5:1-5; The multiple heating and cooling treatments are performed at least twice; the procedure of the heating and cooling treatments is: heating to 550°C at a heating rate of 5 to 20°C / min, keeping the temperature at that temperature for at least 20 minutes, then cooling to 500°C at a cooling rate of 0.2 to 0.5°C / min, and keeping the temperature at that temperature for at least 20 minutes.

4. A supported Sn prepared by the method as claimed in claim 3 24 P 19.3 I8 catalyst.

5. Use of the catalyst according to claim 2 or claim 4 in the preparation of black phosphorus.

6. A method for improving the conversion rate of preparing black phosphorus, characterized in that: The black phosphorus is prepared by catalytic use of the catalyst described in claim 2 or claim 4.

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