Built-in heating device for black phosphorus crystal preparation
Through the built-in heating device and method, the problems of controlling the heating rate and catalyst deactivation in the large-scale preparation of black phosphorus crystals are solved, and efficient and low-cost black phosphorus crystal preparation and continuous production are achieved.
Patent Information
- Application Number
- CN202422540542.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2034-10-21
AI Technical Summary
Existing technologies make it difficult to achieve large-scale preparation of high-quality, high-yield black phosphorus crystals. The external heating control heating rate is difficult to accurately regulate, the catalyst is severely deactivated, there are many by-products and high safety risks, resulting in high preparation costs and low raw material utilization.
By adopting built-in heating devices and methods, through the design of double-layer porous raw material crucible and catalyst crucible, combined with internal and external heaters to control the temperature gradient of the reaction system, and using telescopic separation partitions to realize automatic separation and transportation of raw materials, catalyst recycling and utilization, efficient crystal nucleation and growth are achieved.
The growth efficiency and quality of black phosphorus crystals are improved, the preparation cost is significantly reduced, the raw material utilization rate is increased, and the continuous production of black phosphorus crystals is realized.
Smart Images
Figure CN223342868U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of preparation of a novel two-dimensional material black phosphorus, and in particular to a built-in heating device for preparing black phosphorus crystals. Background Art
[0002] Black phosphorus, with its unique properties such as high carrier mobility, wide and tunable direct band gap, and atomic layer van der Waals integration, has become one of the important alternative materials for next-generation electronic and optoelectronic applications after semiconductor materials such as silicon. Numerous studies have shown that by adjusting the band gap of black phosphorus (0.3-0.2 eV), it is possible to switch between insulating and conducting states, and the electron mobility of black phosphorus is very fast (greater than 1000 cm 2 V -1 s -1 ), the closure is more significant (10 5 ), which has greatly promoted its widespread application in electronic and optoelectronic devices. Due to its unique mechanical properties, electrochemical performance, and thermal anisotropy, black phosphorus is not only used in field-effect transistors, but also shows promising application prospects in various fields such as new energy batteries, high-efficiency catalysis, optoelectronic communications, and biomedicine.
[0003] Compared to the method of preparing black phosphorus crystals through single external heating, the method of adding a built-in heating device and using it to grow black phosphorus crystals can achieve high-yield, high-quality, controllable preparation of black phosphorus crystals. Due to the harsh conditions for preparing black phosphorus, technical problems have led to significant obstacles in industrial-scale production of controllable large-scale growth. Currently, the main methods for preparing black phosphorus worldwide include mineralization, bismuth melting, mechanical ball milling, mercury reflux, and high-pressure methods. Among them, only the mineralization method has been widely recognized by scientists and can be achieved in large-scale production. The preparation of high-quality black phosphorus crystals in a closed reaction system through chemical vapor phase method has attracted widespread attention and plays a vital role in promoting the application of black phosphorus. However, the current mineralization method for preparing black phosphorus still has key bottlenecks: 1. Since it is difficult to precisely control the internal raw material diffusion rate by controlling the heating rate only through external heating to achieve large-scale preparation of crystals in a closed reaction system, the raw materials will agglomerate severely after being heated for a period of time, and only a small amount of phosphorus vapor will migrate, making it difficult to achieve continued nucleation and growth of black phosphorus crystals, resulting in difficulties in the large-scale growth and preparation of black phosphorus crystals; 2. The serious problem of catalyst deactivation has not been verified and analyzed and solved, resulting in insufficient reaction, seriously reducing the catalytic efficiency of the catalyst, and unstable crystal nucleation, making it difficult to achieve efficient large-scale preparation of black phosphorus crystals; 3. After the reaction is completed, there are many by-products that are difficult to recycle, which is prone to endangering the safety of experimental personnel. This makes the black phosphorus preparation cost high, the raw material utilization rate low, and the safety risk high, which is not conducive to large-scale production. To this end, an internal heating device and method for preparing black phosphorus crystals are developed and proposed. Summary of the Invention
[0004] In order to solve the above technical problems, the present invention provides an internal heating device for preparing black phosphorus crystals. The purpose of the present invention is to provide a method for preparing black phosphorus crystals with a built-in heating reaction system to address the bottleneck problem of large-scale preparation of black phosphorus by the above mineralization method. The method is capable of achieving large-scale preparation of high-yield and high-quality products; secondly, a device is designed to provide the necessary basic conditions for the implementation of the method; thirdly, the method and device can significantly improve the utilization rate of raw materials and save the cost of crystal preparation; fourthly, the device can be connected with the current yellow phosphorus tail gas pipeline for filtering and preparing red phosphorus assembly, and the continuous production and preparation of black phosphorus crystals can be achieved by adopting a process treatment route based on yellow phosphorus tail gas.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions:
[0006] A built-in heating device and method for preparing black phosphorus crystals, wherein Figure 1 The schematic diagram of the device shown, the devices mainly used in the reaction system include:
[0007] The reactor of the reaction system mainly includes a cylinder for reaction and a reactor cover for sealing the cylinder;
[0008] The raw material crucible is fixed in the cylinder, and a heater is provided at the bottom of the raw material crucible;
[0009] The raw material crucible has a double-layer structure, with telescopic movement control elements on both sides of the outer layer. The left and right sides of the telescopic units are placed at the lower end of the raw material crucible and fixed. During the raw material feeding process, the raw material is compressed and moved downward; after the reaction starts, the raw material is transported upward, and the telescopic unit expands and moves upward;
[0010] The catalyst crucible is placed on the upper end of the raw material crucible;
[0011] A heater for internally heating the reaction system is connected to an external heating control system;
[0012] The pressure transmitter is connected to the heating control system.
[0013] The raw material crucible has a double-layer structure with a porous structure on the inside. The inner layer of the raw material crucible is a porous structure, and a telescopic separation partition is placed and fixed between the inner and outer layers of the raw material crucible. The telescopic separation partition automatically expands and contracts between the inner and outer layers of the raw material crucible to achieve automatic separation of the raw materials, thereby achieving the transportation of the raw materials. The pore size is 60-80 mesh.
[0014] A catalyst filtering device is provided at the lower part of the raw material crucible, and a catalyst collecting and recovering device is located at the bottom of the cylinder.
[0015] The heater is provided with a temperature detection pipe, and the temperature sensor is connected to the temperature detection pipe to realize the temperature control of the heater;
[0016] The pressure transmitter is connected to the pressure detection pipeline through a pressure regulating valve and is used to detect the pressure in the cylinder.
[0017] A heating furnace for external heating of the entire reaction system is connected to the heating reaction system.
[0018] The heating wire of the heater is made of iron-chromium-aluminum alloy series and nickel-chromium electric heating alloy.
[0019] The method for preparing black phosphorus crystals using a built-in heating reaction system of the utility model comprises the following steps:
[0020] S1, weighing industrial tin powder and activated carbon under a protective gas atmosphere, placing them into a crucible and placing it into a small reactor to be completely sealed. After being completely sealed, heating and activating them in a tube furnace. After being completely activated, taking them out under a protective gas atmosphere and placing them in a sealed bottle for later use;
[0021] S2, under a protective gas atmosphere, open the pressure probe valve of the reaction system, weigh a certain proportion of red phosphorus, carbon-activated tin and iodine and place the red phosphorus and iodine in the reaction raw material crucible respectively, and place the carbon-activated tin catalyst in the catalyst element crucible. The particle size of the red phosphorus and iodine is 50-70 mesh;
[0022] S3, placing the reactor cover on top of the reaction cylinder to completely seal the reactor;
[0023] S4, after the packaging is completed, the heater, external heating system and temperature and pressure detection device in the reaction system are programmed. After the program setting is completed, the heating control system is turned on to heat the reaction system: by programming the temperature of the reactor 1-6 sections, the upper section 1-3 of the reactor is heated from room temperature to 500-530°C in 30-90 minutes, and the lower section 4-6 of the reactor is heated from room temperature to 550-590°C in 30-90 minutes; the reactor is heated by an electric heater, and the reaction system is temperature controlled by the internal heater and the external heating furnace; the built-in heating The temperature of the reaction system is increased by a combined control of the heat exchanger and the external heating furnace. The bottom end is heated from room temperature to 210-300°C at a rate of 3-12°C / min over 15-90min, then to 450-480°C at a rate of 3-12°C / min over 15-70min, and then to 550-600°C at a rate of 5-12°C / min over 8min-24min. The lower end of the upper kettle cover of the sealed cylinder is heated from room temperature to 270-330°C at a rate of 5-12°C / min over 20-60min, and then to 450-480°C at a rate of 3-12°C / min over 15-70min. The temperature is raised to 470-500°C per minute, then raised to 500-590°C over 0-30 minutes at a rate of 3-10°C / min. The heating rate within the reaction system is regulated. The movement rate of the telescopic separation baffle is controlled from 0 cm / s to 5 cm / s. Combined with the pore size of the raw material crucible inner layer of 60-80 mesh, the raw material separation flow rate is regulated from 0 g / s to 100 g / s, and the spring is controlled to rise at a rate of 0.5-3 cm / min. This achieves the production of high-quality and high-yield black phosphorus crystals. The filtered catalyst after the reaction is recovered through a recovery element for secondary use.
[0024] As a preferred technical solution, the mass ratio of tin powder to activated carbon during activation in S1 is tin:carbon = 100:1~50:1, and the activation temperature is 100~200°C.
[0025] As a preferred technical solution, the raw material ratio of the reaction system described in S2 is red phosphorus: tin (carbon): iodine = 100:6:0.5~100:10:4.
[0026] As a preferred technical solution, the raw material crucible of the reaction system described in S2 can achieve efficient conversion and full contact of the catalyst and red phosphorus raw material during the reaction process after the raw materials are heated and separated.
[0027] As a preferred technical solution, the reaction system raw material crucible described in S2 can be moved up and down by the side telescopic element, moved upward by the raw material reaction conversion, and compressed downward to the lowest point by the maximum amount of initial raw materials. The lowest point is located at 1 / 4~1 / 3 of the reaction cylinder.
[0028] As a preferred technical solution, the raw material crucible of the reaction system described in S2 is a double-layer structure and a porous structure with a pore size of 60-80 mesh and a porous structure on the inside. After rapid heating to 480°C, the partitions on both sides of the interval expand thermally and push and pull the inner raw material separation layer of the raw material crucible forward around the inner raw material crucible to realize automatic separation of the raw materials, and contact the catalyst to realize the upward transport of the catalyst and raw materials, and transport them to the lower end of the top reactor cover to start the nucleation and growth of black phosphorus crystals, thereby reducing the probability of material compaction.
[0029] As a preferred technical solution, the material of the heating wire of the heater in S4 is an iron-chromium-aluminum alloy series, a nickel-chromium electric heating alloy, etc.
[0030] As a preferred technical solution, the external heating device in S4 is an external heating furnace and the heating program is a multi-stage controllable heating program. In the temperature heating program of the reactor, the upper 1-3 sections of the reactor are heated from room temperature to 510-520°C in 50-60 minutes, and the lower 4-6 sections of the reactor are heated from room temperature to 550-560°C in 50-60 minutes.
[0031] As a preferred technical solution, the built-in heater heating program in S4 adopts a gradient heating program to achieve the temperature conditions required for the upward transportation of the raw materials. The bottom of the raw material crucible is heated from room temperature to 270°C at 8-10°C / min for 24-30min, then to 470°C at 8-10°C / min for 20-25min, and then to 550-590°C at 8-10°C / min for 8min-15min.
[0032] As a preferred technical solution, the lower end of the upper kettle cover of the sealed cylinder in S4 is heated by gradient heating from room temperature to 260°C at 8-10°C / min over 24-30min, then to 470-500°C at 8-10°C / min over 15-25min, and then to 510-590°C at 8-10°C / min over 1-9min to regulate the heating rate in the reaction system. By controlling the movement rate of the telescopic separation partition to 1cm / s-3cm / s, combined with the inner layer aperture of the raw material crucible to 60-80 mesh, the raw material separation flow rate is regulated to 16g / s-50g / s, and the spring is controlled to rise at a rate of 1.0-3.0 cm / min, and more preferably at a rate of 1-1.5cm / min.
[0033] As a preferred technical solution, the combination of internal and external heating and temperature control described in S4 is used to regulate the heating rate inside the reaction system so that the raw materials can be efficiently and directionally transported and converted in the reaction system.
[0034] As a preferred technical solution, the temperature detection device of the reaction system described in S4 can realize temperature monitoring in the range of 500~600℃ and alarm after over-temperature and stop heating of the reaction system to ensure the safety and stability of the experiment.
[0035] As a preferred technical solution, by increasing the number of feeding times, the amount of iodine fed from the bottom end to the top in the material crucible device is gradually reduced.
[0036] As a preferred technical solution, after the tin reaches the liquefaction temperature in the upper material crucible device, it can be automatically discharged downward through the porous structure. The aperture is 200-300 mesh, and the opening and closing of the adjustment holes are controlled by instructions.
[0037] As a preferred technical solution, the pressure detection pipeline is externally connected to an emergency pressure relief and emptying system.
[0038] Compared with the prior art, the beneficial effects of the present invention are:
[0039] 1) The present invention uses a built-in heating device and method for preparing black phosphorus crystals to prepare high-quality and high-yield black phosphorus crystals. The use of the built-in heater can significantly increase the effective material transport rate, thereby controlling the crystal growth time and improving the crystal growth efficiency and crystal quality.
[0040] 2) This preparation method uses an activated industrial catalyst to significantly improve the catalyst activity, while extending the catalyst's service life and flow efficiency, and prolonging the black phosphorus crystal growth time, thereby significantly improving the black phosphorus crystal growth yield.
[0041] 3) This method is simple and efficient, the conditions are easy to control, and it has good safety and stability. It can reduce the amount of catalyst used and recycle it, fully improve the utilization rate of raw materials, and significantly reduce the cost of preparing high-quality black phosphorus crystals.
[0042] 4) The device is simple to operate and can be automated. It can be connected to the current yellow phosphorus tail gas pipeline for filtering and preparing red phosphorus assembly. By adopting a yellow phosphorus tail gas process treatment route, the continuous production and preparation of black phosphorus crystals can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Figure 1 This is a schematic diagram of the device in the preparation method of Example 1 of the present utility model.
[0044] In the picture:
[0045] Reactor cylinder 1, sealed cylinder lid 2, built-in heater 3, raw material (red phosphorus and transport agent) control element 4, catalyst filtering element 5, catalyst collection and recycling element 6, pressure transmitter 7, pressure probe pipe 8, pressure regulating valve 9, temperature probe pipe 10, temperature sensor 11, external heating control system 12, catalyst control element 13, raw material device up and down movement control element 14; the external heating furnace used for the entire reaction system is connected to the heating reaction system.
[0046] Figure 2 for Figure 1 Schematic diagram of the implementation of the raw material separation control elements within the device.
[0047] Figure 3 for Figure 1 Schematic diagram of the implementation of the raw material crucible telescopic separation plate element in the device.
[0048] Figure 4 for Figure 1 Schematic diagram of the implementation of the control element for the vertical telescopic movement of the raw material crucible in the device.
[0049] Figure 5 for Figure 1 Schematic diagram of the implementation of the catalyst raw material filtering element in the device.
[0050] Figure 6 This is a physical picture of the black phosphorus crystals obtained in Example 1. DETAILED DESCRIPTION
[0051] Example 1
[0052] like Figure 1 A built-in heating device for preparing black phosphorus crystals, the heating device comprising a reaction cylinder 1 and a kettle cover 2 for sealing the cylinder;
[0053] The raw material crucible 4 is fixed in the cylinder 1, and a heater 3 is provided at the bottom of the raw material crucible 4;
[0054] The raw material crucible 4 is a double-layer structure, with telescopic movement control elements on both sides of the outer layer. The left and right sides of the telescopic units are placed at the lower end of the raw material crucible and fixed. During the raw material feeding process, downward compression movement is achieved; after the reaction starts, the raw material is transported upward, and the telescopic unit expands and moves upward;
[0055] The catalyst crucible 13 is placed on the upper end of the raw material crucible 4;
[0056] The heater 3 for internally heating the reaction system is connected to the external heating control system 12;
[0057] The pressure transmitter 7 is connected to the heating control system 12 .
[0058] The inner layer of the raw material crucible 4 is a porous structure, which is fixed between the inner and outer layers of the raw material crucible through a telescopic separation partition. The telescopic separation partition 15 is automatically telescopically arranged between the inner and outer layers of the raw material crucible to realize the automatic separation of the raw materials. The automatic telescopic device realizes the automatic separation of the raw materials, thereby realizing the transportation of the raw materials. The pore size is 60-80 mesh.
[0059] A catalyst filtering device 5 is provided at the lower part of the raw material crucible 4 , and a catalyst collecting and recovering device 6 is located at the bottom of the cylinder 1 .
[0060] The heater 3 is provided with a temperature detection pipe 10, and a temperature sensor 11 is connected to the temperature detection pipe 10 to realize the temperature control of the heater;
[0061] The pressure transmitter 7 is connected to the pressure detection pipe 8 through the pressure control valve 9 and is used to detect the pressure in the cylinder 1.
[0062] The method for preparing black phosphorus crystals using the above device has the following specific steps:
[0063] 1) Under a protective gas atmosphere, industrial tin powder and activated carbon were weighed and placed in a crucible, which was then placed in a small reactor and completely sealed. After the crucible was completely sealed, it was heated and activated in a tube furnace at a ratio of tin:carbon = 100:1, the activation temperature was 200°C, and the activation time was 1 hour. After complete activation, the crucible was removed from the crucible under a protective gas atmosphere and placed in a sealed bottle for later use.
[0064] 2) Under a protective gas atmosphere, open the pressure probe valve to perform vacuum ventilation on the reaction system. Weigh 10 kg of red phosphorus, 1 kg of activated catalyst Sn (C), and 0.4 kg of transport agent I2 in a ratio of 100:10:4, and place the raw materials in the raw material crucible in the reactor in the order and at the designated position.
[0065] 3) Place the reactor cover on top of the reaction cylinder to completely seal the reactor;
[0066] 4） After the packaging is completed, the temperature control program of the internal heater and the external heating furnace is adjusted, and the external heating furnace is programmed to heat up. The upper section 1-3 of the reaction furnace is heated from room temperature to 510°C over 60 minutes, and the lower section 4-6 of the reaction furnace is heated from room temperature to 550°C over 60 minutes. Specifically, the temperature is increased by electric heating gradient in the reactor. The bottom end of the raw material crucible is heated in the reactor from room temperature to 270°C at 8°C / min over 30 minutes, then to 470°C at 8°C / min over 25 minutes, and then to 550°C at 8°C / min over 10 minutes.
[0067] The temperature of the lower end of the upper kettle cover of the sealed cylinder was raised from room temperature to 270°C over 30 minutes at a rate of 8°C / min, then to 470°C over 25 minutes at a rate of 8°C / min, and finally to 510°C over 5 minutes. The movement rate of the telescopic separation baffle was controlled at 3.0 cm / s, while the spring was controlled to rise at a rate of 1 cm / min. During the heating process, the inner and outer layers of the raw material crucible were fixed. The inner layer of the raw material crucible had a double-layer structure (one fixed layer, the other two staggered separation layers). Rotational separation of the raw materials was achieved by the circular movement and extension of the staggered separation layers on both sides of the telescopic separation baffle as the temperature increased.
[0068] When the pore size is 70 mesh, the separation flow rate of the raw materials in the raw material crucible is 50 g / s. After 30 minutes, 10 kg of red phosphorus raw materials are vaporized under heating conditions within the range of 480-590°C in the local environment after continuous separation. At the same time, the catalyst tin gradually liquefies after the temperature rises to 260°C to reach its melting point and flows downward through the holes at a rate of 30 min / kg. When the red phosphorus is vaporized, it contacts the vaporized red phosphorus and the volatilized gaseous iodine, and the three are transported upward. A phosphorus iodine tin intermediate is quickly formed within the range of 500-520°C and crystal nucleation growth begins. The filtered catalyst after the reaction is recovered through a recovery element and reused.
[0069] Control the valve switch of the pipeline channel to open and close the pipeline;
[0070] After the reaction is completed, the reactor is transferred to a safe operating area for pressure relief and opening. After the pressure is completely relieved, the reactor cover flange is removed and the sample is taken out using a sampler. Finally, a two-dimensional stable black phosphorus crystal block is obtained, and 9.2 kg of product is obtained.
Claims
1. A built-in heating device for preparing black phosphorus crystals, characterized in that: The heating device comprises a reaction cylinder (1) and a kettle cover (2) for sealing the cylinder; The raw material crucible (4) is fixed in the cylinder (1), and a heater (3) is provided at the bottom of the raw material crucible (4); The raw material crucible (4) is a double-layer structure, with telescopic movement control elements (14) provided on both sides of the outer layer. The left and right sides of the telescopic units are both placed at the lower end of the raw material crucible and fixed, so that the raw material is compressed and moved downward during the feeding process; after the reaction starts, the raw material is transported upward, and the telescopic unit is expanded and moved upward; The catalyst crucible (13) is placed on the upper end of the raw material crucible (4); A heater (3) for internally heating the reaction system is connected to an external heating control system (12); The pressure transmitter (7) is connected to the heating control system (12).
2. The built-in heating device for preparing black phosphorus crystals according to claim 1, characterized in that: The inner layer of the raw material crucible (4) is a porous structure, and a telescopic separation partition is fixed between the inner and outer layers of the raw material crucible. The telescopic separation partition (15) is automatically telescopically arranged between the inner and outer layers of the raw material crucible to realize automatic separation of the raw materials, thereby realizing the transportation of the raw materials. The aperture size is 60-80 mesh.
3. The built-in heating device for preparing black phosphorus crystals according to claim 1, characterized in that: A catalyst filtering device (5) is provided at the bottom of the raw material crucible (4), and a catalyst collecting and recovering device (6) is located at the bottom of the cylinder (1).
4. The built-in heating device for preparing black phosphorus crystals according to claim 1, characterized in that: The heater (3) is provided with a temperature detection pipe (10), and a temperature sensor (11) is connected to the temperature detection pipe (10) to realize the temperature control of the heater.
5. The built-in heating device for preparing black phosphorus crystals according to claim 1, characterized in that: The pressure transmitter (7) is connected to the pressure detection pipe (8) through the pressure control valve (9) and is used to detect the pressure in the cylinder (1).