Preparation method of low-cost black phosphorus crystal

Abstract

The invention discloses a preparation method of a low-cost black phosphorus crystal. Wherein the black phosphorus crystal preparation device is a reactor, and is specifically characterized in that a rail capable of moving up and down is mounted on a raw material end pipe wall of the inner wall of the reactor. The method comprises the following steps: firstly, putting a certain amount of phosphorus raw material, catalyst and transport agent at the raw material end of a reactor in an inert atmosphere, putting a partition plate into the reactor after all the materials are fed, enabling the partition plate to move up and down at the raw material end of the reactor, fixing the partition plate on a track after the partition plate reaches a proper position, and then sealing the nucleation end of the reactor; a heating program is set for heating, and the reactor is opened after the program is finished, so that high-quality black phosphorus crystals can be obtained. All by-products are attached to the partition plate, and the partition plate is taken down to be collected so as to be conveniently used next time (instead of a catalyst). The method is simple to operate, simple in process, stable in quality, high in efficiency and convenient for recycling byproducts, and the product production cost is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of phosphorus element preparation, and in particular relates to a method for preparing low-cost black phosphorus crystals. Background Art

[0002] The discovery of black phosphorus can be traced back to 1914, when American scientists successfully prepared block black phosphorus through high temperature and high pressure. Although black phosphorus did not receive widespread attention in the early days, with the discovery and widespread application of graphene, black phosphorus has gradually received attention due to its excellent properties similar to graphene.

[0003] Black phosphorus has been widely used in many fields due to its excellent physical and chemical properties, mainly including the first energy field: black phosphorus, as the negative electrode material of lithium ion capacitors, has a high theoretical specific capacity (2596 mAh g⁻¹) and an appropriate lithiation potential (0.7 V vs Li+ / Li), which is suitable for fast charging of lithium ion capacitors. The cycle performance and capacity can be significantly improved by using black phosphorus electrodes modified with functional adhesives; the second is electronic and optoelectronic devices: black phosphorus has an adjustable band gap, high mobility and good biocompatibility, and is suitable for photodetectors and optoelectronic devices; the third is the biomedical field: black phosphorus nanosheets are used for disease treatment, drug carriers and clinical testing due to their large specific surface area and good biocompatibility.

[0004] So far, the biggest challenge facing the research and application of black phosphorus is how to efficiently prepare high-quality black phosphorus crystals in large quantities at low cost. The chemical vapor transport method, such as CN113559886A, is widely used. It is mentioned that "phosphorus iodine tin powder and carbon material additive are mixed and ground evenly and then pressed into shape" in the process of preparing black phosphorus crystals. The carbon material additive is additionally added, which increases the preparation cost and is not conducive to large-scale preparation. In CN109305661A, Sn4P3 is used as a catalyst to efficiently prepare two-dimensional black phosphorus crystals, and Sn4P3 also needs additional synthesis, which greatly increases energy consumption and the time required. The corresponding increase in energy consumption is bound to affect the production cost of black phosphorus crystals, which is not conducive to the efficient preparation of black phosphorus crystals.

[0005] In summary, there is no report on the recycling of byproducts in the preparation process of black phosphorus crystals and using them as catalysts again. Therefore, developing a low-cost preparation method for black phosphorus crystals to solve the problems of low raw material utilization, poor byproduct recycling, inconvenient reactor cleaning, and high production costs in the existing scale-up preparation process is of great value in expanding the industrial application of black phosphorus materials in many fields such as energy, electronic and optoelectronic devices, and biomedicine. Summary of the invention

[0006] In view of the above technical problems, the present invention provides a method for preparing black phosphorus crystals at a low cost, comprising the following steps: (1) The bottom of the vertical reactor is used as the raw material end, the top is used as the nucleation end, and the middle is used as the transition end. The raw material end is sealed before feeding; (2) placing a mixture of a phosphorus source, a catalyst, and a transport agent at the raw material end under an inert atmosphere; (3) Tracks are arranged on both sides of the raw material end of the vertical reactor, and baffles are fixed on the tracks; (4) The raw material end, transition section, and nucleation end are heated in sequence to achieve the preparation of black phosphorus crystals.

[0007] In the step (1), the length of the vertical reactor is 800mm-1300mm and the diameter is 350mm-600mm. In the vertical reactor, the length of the raw material end is 300mm-500mm, the length of the transition end is 200mm-350mm, and the length of the nucleation end is 250-450mm. The raw material starts to heat up and react from the raw material end, and then undergoes temperature heating at the transition end and the nucleation end, and finally the preparation of black phosphorus is achieved.

[0008] In step (2), the mass ratio of phosphorus source: catalyst: transport agent is 100:4-20:3-10, the purity of red phosphorus in the phosphorus source is above 98.5%; the purity of SnI4 and I2 in the transport agent is above 98.0%; the catalyst is at least one of Sn, Bi, In, Pb, and Cd, and the purity is above 98.0%.

[0009] The catalyst also includes a by-product produced on the partition after the reaction of step (1) to step (4), wherein the by-product is selected from Sn 24 P 19.3 I8, Sn4P3, P 8.76 Sn 11.98 、Sn9P 12.12 The catalyst (by-product) is selected in the order of high Sn content to low Sn content.

[0010] In some embodiments, when the by-product is used as a catalyst, the obtained by-product is washed with water, crushed, washed with alcohol, vacuum dried, and pulverized and then used as a catalyst for the next reaction. The particle size after pulverization is 0.1mm-2mm; preferably, the particle size of the powder is 0.5mm-1.5mm.

[0011] In the technical solution of the present application, a certain amount of by-products will be produced during the reaction of the mixture at the raw material end. The technical solution of the present application enables the by-products to grow on the partition, so that after one reaction is completed, the by-products can be smoothly peeled off from the partition and used as a catalyst for the next reaction.

[0012] The track length is 1 / 5-1 / 2 of the total length of the reactor; preferably, the track length is 1 / 4-1 / 3 of the length of the reactor (calculated from the raw material end pipe opening).

[0013] The length of the track is 1 / 5-1 / 2 of the total length of the reactor; the material of the track and the partition is high entropy carbide ceramic material, and the thickness of the partition is 2-6mm.

[0014] The high entropy carbide ceramic material is selected from (HfMoNbTaTi)C, (Ti 1 / 3 Nb 1 / 3 Ta 1 / 3 )2AlC、(Ti 1 / 4Zr 1 / 4 Nb 1 / 4 Ta 1 / 4 )2AlC.

[0015] The rail and the partition are made of 316L stainless steel, and high entropy carbide ceramic material is attached to the 316L stainless steel. The thickness of the partition is 1-3mm.

[0016] The high entropy carbide ceramic material is selected from (HfMoNbTaTi)C, (Ti 1 / 3 Nb 1 / 3 Ta 1 / 3 )2AlC、(Ti 1 / 4Zr 1 / 4 Nb 1 / 4 Ta 1 / 4 )2AlC.

[0017] The functions of high entropy carbide ceramic materials are: first, they have excellent corrosion resistance, which can better protect the partitions and rails from corrosion and increase the number of times the partitions and rails are used; second, they can achieve directional growth of side reactions, achieve better separation after one reaction, and promote the next catalytic reaction.

[0018] The partition is provided with circular holes of different apertures with a diameter of 5mm-20mm, and the distance between the centers of two adjacent holes is 10mm-30mm; the area of ​​the circular holes on the partition is 1 / 2-3 / 5 of the area of ​​the partition, and preferably, the area of ​​the circular holes on the partition is 1 / 3-3 / 4 of the area of ​​the partition, so that the gas at the raw material end can pass through the circular holes to reach the nucleation end.

[0019] The temperature rise in the step (4) is controlled by three sections of heating wires, and the specific procedure is as follows: the raw material end is heated to 530-570°C for 1-2 hours at room temperature, then kept warm for 15-24 hours, and then cooled to room temperature for 6-15 hours; the middle end is heated to 510-540°C for 1-2 hours at room temperature, then kept warm for 15-24 hours, and then cooled to room temperature for 6-15 hours; the nucleation end is heated to 470-500°C for 1-2 hours at room temperature, then kept warm for 15-24 hours, and then cooled to room temperature for 6-15 hours.

[0020] In some specific embodiments, the temperature rise in the step (4) is controlled by three sections of heating wires, and the specific procedure is as follows: the raw material end is heated to 540-560°C for 1-2 h at room temperature, then kept warm for 18-20 h, and then cooled to room temperature for 8-12 h; the middle end is heated to 520-550°C for 1-2 h at room temperature, then kept warm for 18-20 h, and then cooled to room temperature for 8-12 h; the nucleation end is heated to 480-490°C for 1-2 h at room temperature, then kept warm for 18-20 h, and then cooled to room temperature for 8-12 h.

[0021] The present invention adopts a low-cost method for preparing black phosphorus crystals. The reactor is installed with a track to allow the partition to move up and down to find the position where the by-product (tin-phosphorus-iodine compound) grows, and finally the by-product (tin-phosphorus compound) is completely grown on the partition. After the reaction is completed, the partition can be removed to remove all the by-products.

[0022] The catalyst of the present invention can be reused to save production costs. The catalyst contains not only tin but also phosphorus. The single tin recovery rate is about 50%. Phosphorus can continue to participate in the reaction as a phosphorus source for the next reaction, thereby further improving the yield of black phosphorus crystals.

[0023] The by-product treatment process involved in the method of the present invention is simple, highly safe, easy to repeat, and can be synthesized in large quantities. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a diagram of the internal structure of the reactor of the present invention and the placement of the partition. Among them, 1. vertical reactor, 2. track, 3. partition.

[0025] Figure 2 It is a structural front view of the partition of the present invention.

[0026] Figure 3 This is the X-ray diffraction spectrum of the by-products of steps (4) and (5) in Example 1. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the embodiments.

[0028] The material of the track and the partition of the present invention is high entropy carbide ceramic material (HfMoNbTaTi) C, and the thickness of the partition is 2 mm after melting. The track also uses high entropy carbide ceramic material (HfMoNbTaTi) C.

[0029] Example 1 A low-cost method for preparing black phosphorus crystals comprises the following steps: (1) The bottom of the vertical reactor is used as the raw material end, the top is used as the nucleation end, and the middle is used as the transition end. The raw material end is sealed before feeding; (2) Under an inert atmosphere, a mixture containing a phosphorus source, a catalyst, and a transport agent is placed at the raw material end; the mass ratio of phosphorus source: catalyst: transport agent is 100:10:8 (i.e., 10 kg, 1 kg, 0.8 kg), the purity of red phosphorus in the phosphorus source is 99.5%; the purity of SnI4 in the transport agent is 98.5; the catalyst is Sn, and the purity is 98.8%; (3) Tracks are set on both sides of the raw material end of the vertical reactor, and partitions are fixed on the tracks; the length of the track is 1 / 3 of the total length of the reactor; the track and the partition are made of high entropy carbide ceramic material (HfMoNbTaTi)C, and the thickness of the partition is 2mm. The partition is provided with circular holes with different diameters including 5mm, 8mm, 12mm, 15mm, and 20mm, and the distance between the centers of two adjacent holes is 10mm-30mm; the area of ​​the circular holes on the partition is 3 / 4 of the area of ​​the partition, so that the gas at the raw material end passes through the circular holes to reach the nucleation end. The distance between the partition and the material at the raw material end is 8cm.

[0030] (4) The raw material end, transition section, and nucleation end are heated in sequence to achieve the preparation of black phosphorus crystals.

[0031] The temperature rise was controlled by three sections of heating wires, and the specific procedure was as follows: the raw material end was heated to 570°C for 1 h at room temperature, then kept warm for 20 h, and then cooled to room temperature for 9 h; the middle end was heated to 540°C for 1 h at room temperature, then kept warm for 20 h, and then cooled to room temperature for 9 h; the nucleation end was heated to 500°C for 1 h at room temperature, then kept warm for 20 h, and then cooled to room temperature for 9 h.

[0032] The above process was used to prepare 9.2 kg of black phosphorus, and 0.63 kg of by-products were produced, among which the by-products included Sn. 24 P 19.3 I8, Sn4P3, P 8.76 Sn 11.98 The by-product is washed with water, crushed, washed with alcohol, vacuum dried, and pulverized to be used as a catalyst for the next reaction, wherein the particle size of the pulverized product is 0.5 mm to 1.5 mm.

[0033] (5) The obtained by-product is replaced with the catalyst Sn in this embodiment, and the reaction process from step (1) to step (4) is carried out. 9.3 kg of black phosphorus is prepared by the above process, and 0.59 kg of by-products are produced, wherein the by-products mainly include Sn 24 P 19.3 A mixture of I8 and Sn4P3.

[0034] (6) The byproduct obtained in step (5) is washed with water, crushed, washed with alcohol, vacuum dried, and powdered, and then used as a catalyst for the next reaction. The particle size of the powdered product is 0.5 mm to 1.5 mm. The byproduct is used as a catalyst again to carry out the reaction process from step (1) to step (4). 8.8 kg of black phosphorus was prepared by the above process, and 0.50 kg of byproducts were produced, wherein the byproducts mainly include Sn 24 P 19.3 I8.

[0035] Example 2 The method and steps are the same as those in Example 1, except that the catalyst is replaced by Sn4P3. Then, 9.1 kg of black phosphorus is obtained in step (4), and 0.56 kg of by-products are produced, wherein the by-product is Sn 24 P 19.3 The by-product is washed with water, crushed, washed with alcohol, vacuum dried, and powdered to be used as a catalyst for the next reaction, wherein the particle size of the powdered product is 0.5 mm to 1.5 mm.

[0036] (5) The by-product obtained was replaced with the catalyst Sn4P3 in this embodiment, and the reaction process from step (1) to step (4) was carried out. 8.9 kg of black phosphorus was prepared by the above process, and 0.58 kg of by-products were produced, wherein the by-products mainly included Sn 24 P 19.3 I8.

[0037] (6) The byproduct obtained in step (5) is washed with water, crushed, washed with alcohol, vacuum dried, and powdered, and then used as a catalyst for the next reaction. The particle size of the powdered product is 0.5 mm to 1.5 mm. The byproduct is used as a catalyst again to carry out the reaction process from step (1) to step (4). 8.2 kg of black phosphorus was prepared by the above process, and 0.45 kg of byproducts were produced, wherein the byproducts mainly include Sn 24 P 19.3 I8.

[0038] Example 3 The method and steps are the same as those in Example 1, except that the material of the partition is 304 stainless steel. Then, 9.18 kg of black phosphorus is obtained in step (4), and 0.65 kg of by-products are produced, wherein the by-products mainly include Sn24 P 19.3 The by-product is washed with water, crushed, washed with alcohol, vacuum dried, and powdered to be used as a catalyst for the next reaction, wherein the particle size of the powdered product is 0.5 mm to 1.5 mm.

[0039] (5) The obtained by-product is replaced with the catalyst Sn in this embodiment, and the reaction process from step (1) to step (4) is carried out. 5.7 kg of black phosphorus is prepared by the above process, and 0.60 kg of by-products are produced, wherein the by-products mainly include Sn 24 P 19.3 I8.

[0040] (6) The byproduct obtained in step (5) is washed with water, crushed, washed with alcohol, vacuum dried, and powdered, and then used as a catalyst for the next reaction. The particle size of the powdered product is 0.5 mm to 1.5 mm. The byproduct is used as a catalyst again to carry out the reaction process from step (1) to step (4). 4.6 kg of black phosphorus was prepared by the above process, and 0.57 kg of byproducts were produced, wherein the byproducts mainly include Sn4P3.

[0041] It should also be noted that the various specific technical features described in the above specific embodiments are willing to be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe various possible combinations one by one.

Claims

1. A low-cost method for preparing black phosphorus crystals, characterized in that: The steps include: (1) The bottom of the vertical reactor is used as the raw material end, the top is used as the nucleation end, and the middle is used as the transition end. The raw material end is sealed before feeding; (2) placing a mixture of a phosphorus source, a catalyst, and a transport agent at the raw material end under an inert atmosphere; (3) Tracks are arranged on both sides of the raw material end of the vertical reactor, and baffles are fixed on the tracks; (4) The raw material end, transition section, and nucleation end are heated in sequence to achieve the preparation of black phosphorus crystals.

2. The low-cost black phosphorus crystal preparation method according to claim 1, characterized in that: In step (2), the mass ratio of phosphorus source: catalyst: transport agent is 100:4-20:3-10, the purity of red phosphorus in the phosphorus source is above 98.5%; the purity of SnI4 and I2 in the transport agent is above 98.0%; the catalyst is at least one of Sn, Bi, In, Pb, and Cd, and the purity is above 98.0%.

3. The low-cost black phosphorus crystal preparation method according to claim 1, characterized in that: The catalyst also includes a by-product produced on the partition after the reaction of step (1) to step (4), wherein the by-product is selected from Sn 24 P 19.3 I8, Sn4P3, P 8.76 Sn 11.98 、Sn9P 12.12 One or a mixture of several.

4. The low-cost black phosphorus crystal preparation method according to claim 1, characterized in that: The length of the track is 1 / 5-1 / 2 of the total length of the reactor; the material of the track and the partition is high entropy carbide ceramic material, and the thickness of the partition is 2-6mm.

5. The low-cost black phosphorus crystal preparation method according to claim 1, characterized in that: High entropy carbide ceramic materials are selected from (HfMoNbTaTi)C, (Ti 1 / 3 Nb 1 / 3 Ta 1 / 3 )2AlC、(Ti 1 / 4 Zr 1 / 4 Nb 1 / 4 Ta 1 / 4 )2AlC.

6. The low-cost black phosphorus crystal preparation method according to claim 4 or 5, characterized in that: The rail and the partition are made of 316L stainless steel, and high entropy carbide ceramic material is attached to the 316L stainless steel. The thickness of the partition is 1-3mm.

7. The low-cost black phosphorus crystal preparation method according to claim 6, characterized in that: High entropy carbide ceramic materials are selected from (HfMoNbTaTi)C, (Ti 1 / 3 Nb 1 / 3 Ta 1 / 3 )2AlC、(Ti 1 / 4 Zr 1 / 4 Nb 1 / 4 Ta 1 / 4 )2AlC.

8. The low-cost black phosphorus crystal preparation method according to claim 7, characterized in that: The partition is provided with circular holes of different apertures with a diameter of 5mm-20mm, and the distance between the centers of two adjacent holes is 10mm-30mm; the area of ​​the circular holes on the partition is 1 / 3-3 / 4 of the area of ​​the partition, so that the gas at the raw material end can pass through the circular holes to reach the nucleation end.

9. The low-cost black phosphorus crystal preparation method according to claim 8, characterized in that: The distance between the partition and the raw material end is 3-15cm.

10. The low-cost black phosphorus crystal preparation method according to claim 1, characterized in that: In step (4), the temperature rise is controlled by three sections of heating wires, and the specific procedure is as follows: the raw material end is heated to 530-570°C for 1-2 h at room temperature, then kept warm for 15-24 h, and then cooled to room temperature for 6-15 h; the middle end is heated to 510-540°C for 1-2 h at room temperature, then kept warm for 15-24 h, and then cooled to room temperature for 6-15 h; the nucleation end is heated to 470-500°C for 1-2 h at room temperature, then kept warm for 15-24 h, and then cooled to room temperature for 6-15 h.

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