A high-activity catalyst for preparing black phosphorus and preparation method thereof

Abstract

The present invention discloses a high-activity catalyst for preparing black phosphorus and a preparation method thereof, belonging to the technical field of new phosphorus chemical materials. The catalyst of the present invention is P a I b Sn c Te d The specific preparation method is to grind phosphorus, tin tetraiodide, tin and doping element A into a uniform mixture and then add them into a reactor. Under the condition of inert gas or vacuum, the reactor is heated by a heater with a preset heating and cooling program to obtain a block P. a I b Sn c Te d The compound is ground into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Te d The present invention can not only quickly and efficiently prepare high purity P a I b Sn c Te d Catalyst, and the prepared doped catalyst has extremely high catalytic activity for black phosphorus preparation.

Description

Technical Field

[0001] The invention relates to a catalyst for preparing black phosphorus and a preparation method thereof, belonging to the technical field of new phosphorus chemical materials. Background Art

[0002] Black phosphorus is an allotrope of phosphorus with a two-dimensional layered structure. Due to its unique in-plane anisotropy, adjustable direct band gap, high carrier mobility, good in vivo biodegradability and biocompatibility, large specific surface area, and multiple active sites, it has broad application prospects in energy storage, catalysis, sensing, medicine, flame retardancy, and lubrication.

[0003] Research on the preparation of black phosphorus has undergone years of development. Since the high-pressure method for preparing black phosphorus, numerous methods have been developed, including mercury catalysis, bismuth melting, mechanical ball milling, chemical vapor deposition, molten salts, and mineralization. Among these, the mineralization method (catalytic method) is the most widely studied and applied, and also holds the greatest potential for achieving continuous production of black phosphorus. Black phosphorus was first prepared using the mineralization method, using gold, tin powder, and tin tetraiodide as mineralizers, mixed with red phosphorus in a specific mass ratio in a vacuum quartz ampoule. The mixture was heated to 600°C under low pressure and then gradually cooled to room temperature. Later, the process was optimized, eliminating the addition of precious metal gold. Instead, tin and tin tetraiodide were used as mineralizers. The mixture was heated to 650°C with red phosphorus, then cooled to 500°C. After a period of holding, the mixture was cooled and subsequently cooled, resulting in higher-purity and larger black phosphorus crystals.

[0004] The existing technology uses a certain amount of tin, tin tetraiodide and red phosphorus as raw materials to prepare Sn 24 P 19.3 I8 ternary complex, and used it as a catalyst to heat it together with red phosphorus to prepare black phosphorus crystals; Sn 24 P 19.3 I8 ternary complex (hereinafter referred to as PISn) is a catalyst for the preparation of black phosphorus. PISn catalyst can be used to prepare black phosphorus with high purity and crystallinity under relatively mild conditions. However, current PISn catalysts have problems such as low activity, long preparation time required to achieve high conversion rates, and long catalyst preparation time and high energy consumption.

[0005] Therefore, developing a highly active black phosphorus catalyst and its preparation method, and optimizing the catalyst preparation time are of great significance for achieving continuous production of black phosphorus and industrial-grade application of black phosphorus materials in many fields. Summary of the Invention

[0006] In view of the problem that the existing catalyst has low activity, the purpose of the present invention is to provide a new catalyst for preparing black phosphorus, which is Pa I b Sn c Te d , the value of a is 10~30, the value of b is 5~15, the value of c is 15~30, and the value of d is 1~30.

[0007] In view of the problems existing in the existing black phosphorus PISn catalyst preparation method, another object of the present invention is to provide a method for preparing a catalyst for preparing black phosphorus, which can not only greatly improve the catalytic activity of the catalyst, but also can quickly, stably and efficiently achieve the doping of modified PISn. a I b Sn c Te d The preparation of the catalyst specifically comprises the following steps:

[0008] (1) Weigh phosphorus, tin tetraiodide, tin, and tellurium, grind them, and mix them evenly; wherein the mass ratio of phosphorus, tin tetraiodide, tin, and tellurium is 1:(1-5):(3-10):(0.1-10).

[0009] (2) The materials uniformly mixed in step (1) are placed into a reactor, and the tube opening is sealed with a sealing film.

[0010] (3) Remove the sealing film from the reactor in step (2), and quickly evacuate the reactor or fill it with inert gas to seal it.

[0011] (4) The reactor sealed in step (3) is heated using a heater with a preset heating and cooling program.

[0012] (5) After the reaction is completed, open the reactor in step (4) to obtain a block P a I b Sn c Te d , take it out and grind it into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Te d .

[0013] In the above scheme, the reactor is a solid sealable reactor.

[0014] Preferably, the reactor is any one of a quartz reactor, a ceramic reactor or a metal reactor.

[0015] In the above solution, the internal atmosphere of the reactor is a vacuum or inert gas atmosphere.

[0016] Preferably, the inert gas includes any one of argon, nitrogen and helium.

[0017] In the above solution, the heater is any one of a resistance heater, an electromagnetic heater or a microwave heater.

[0018] In the above scheme, the heating treatment procedure of heating and cooling is specifically as follows: under room temperature conditions, the temperature is raised to 450-650°C over 50-300 minutes, kept warm for 120-1800 minutes, and then cooled to room temperature at a cooling rate of 1-150°C / min.

[0019] Preferably, the heating treatment procedure of heating and cooling is as follows: under room temperature conditions, the temperature is raised to 500-550°C over 50-120 minutes, kept warm for 300-1800 minutes, and then cooled to room temperature at a cooling rate of 1-150°C / min.

[0020] In the above solution, the tin and tellurium are in the form of any one of powder, foil, granule, strip or block, or a combination of at least two of them.

[0021] Preferably, the tin and tellurium are in the form of any one of powder, foil, and granules, or a combination of at least two of them.

[0022] In the above scheme, the mass feed ratio of phosphorus, tin tetraiodide, tin and tellurium is 1:(1-5):(3-10):(0.1-10).

[0023] Preferably, the mass feed ratio of phosphorus, tin tetraiodide, tin and tellurium is 1:(2-3):(4-6):(0.3-3).

[0024] Beneficial effects of the present invention:

[0025] (1) The doped modified P a I b Sn c Te d Compared with the existing PISn ternary complex catalyst, the doped element Te reacts with some phosphorus atoms in the catalyst to form P-Te bonds, which makes the PISn catalyst expose more P vacancies and active sites, which is more conducive to the adsorption reaction of P4 molecules, thereby greatly improving the catalytic activity. Compared with the existing PISn catalyst, the black phosphorus yield of the PISn catalyst is 14.7% when kept at 535℃ for 30min, and 98.1% when kept at 535℃ for 8h. a I b Sn c Te d The catalyst was used to prepare black phosphorus. Under the condition of keeping the temperature at 535℃ for 30min, the yield of black phosphorus was 98.7%.

[0026] (2) The present invention can not only prepare P with extremely high catalytic activity a I b Sn c Te d The catalyst can also greatly shorten the preparation time; the preparation of the existing PISn catalyst requires first heating to 550 ° C, then repeatedly keeping the temperature at 550 ° C and 500 ° C and raising and lowering the temperature 6 times, and finally naturally cooling to room temperature, which takes 32 hours; while the preparation of P a I b Sn c Te d The shortest preparation time of the catalyst is only 5 hours of constant temperature heating to achieve the best catalytic effect. There is no need to repeatedly raise and lower the temperature during the preparation process, and the energy consumption is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 P prepared in Example 1 a I b Sn c Te d Actual photo of the catalyst;

[0028] Figure 2 P prepared in Example 1 a I b Sn c Te d SEM images of the catalyst;

[0029] Figure 3 P prepared in Example 1 a I b Sn c Te d Catalyst Mapping diagram;

[0030] Figure 4 P prepared in Example 1 a I b Sn c Te d XPS pattern of the catalyst;

[0031] Figure 5 P prepared in Example 1 a I b Sn c Te d XRD pattern of the catalyst;

[0032] Figure 6 P prepared in Example 1 a I b Sn c Te d A photo of black phosphorus obtained after the catalyst reacts with red phosphorus;

[0033] Figure 7 P prepared in Example 1 a I b Sn c Te d SEM image of black phosphorus obtained after the catalyst reacts with red phosphorus;

[0034] Figure 8 P prepared in Example 1 a I b Sn c Te d XRD pattern of black phosphorus obtained after the reaction of the catalyst with red phosphorus;

[0035] Figure 9 P prepared in Example 1 a I b Sn c Te d Raman spectrum of black phosphorus obtained after the catalyst reacts with red phosphorus;

[0036] Figure 10 P prepared in Example 1 a I b Sn c Te d EDS spectrum of black phosphorus obtained after the reaction of the catalyst with red phosphorus. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below through examples, but the scope of protection of the present invention is not limited to the contents described in the following examples; wherein, Comparative Example 1 is a preparation method of a traditional PISn catalyst and its effect in preparing black phosphorus, to compare P a I b Sn c Te d The invention relates to a preparation method of a catalyst and the effect of using the catalyst in preparing black phosphorus.

[0038] Example 1

[0039] A method for preparing a highly active doped modified black phosphorus catalyst P a I b Sn c Te d The specific steps are as follows:

[0040] (1) Phosphorus, tin tetraiodide, tin, and tellurium were weighed in a mass ratio of 1:2:4:0.35, ground, and mixed evenly.

[0041] (2) Place the evenly mixed materials into a quartz tube and seal the tube opening with a sealing film.

[0042] (3) Remove the sealing film and quickly vacuum-seal the quartz tube.

[0043] (4) The quartz tube was heated using a tubular furnace with a pre-set heating and cooling program. The specific program was as follows: at room temperature, the temperature was raised to 550°C at a rate of 5°C / min, kept at that temperature for 1800 min, and then cooled. The heating program was stopped at the holding temperature, and the tubular furnace was opened to allow the temperature to drop to room temperature within 5 min.

[0044] (5) After the reaction is completed, the block P is obtained a I b Sn c Te d The compound is taken out and ground into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Te d .

[0045] The obtained P a I b Sn c Te d The catalyst physical picture, SEM picture and mapping picture are as follows: Figure 1 、 Figure 2 and Figure 3 As shown; From the SEM picture, it can be seen that P a I b Sn c Te d The morphology of the catalyst is not significantly different from that of the pure PISn catalyst. The mapping diagram shows that the Te element is evenly distributed in the catalyst. a I b Sn c Te d The XPS and XRD patterns of the catalysts are shown in Figure 2. Figure 4 and Figure 5 shown by Figure 4 It can be seen from the XPS spectrum of the catalyst and P a I b Sn c Te d The Te peak spectrum of the catalyst shows that Te3d 5 / 2 peak and Te3d 3 / 2 peak, proving that the prepared modified catalyst is indeed P a I b Sn c Te d catalyst; In addition, the comparison of pure PISn catalyst and P a I b Sn c Ted The P2p spectrum of the catalyst shows that P a I b Sn c Te d P2p of Catalyst 1 / 2 Peak and P2p 3 / 2 The peak shifted significantly and the area changed significantly. a I b Sn c Te d The Sn3d spectrum of the catalyst shows that P a I b Sn c Te d Sn3d of the catalyst 3 / 2 Peak and Sn3d 5 / 2 The peak also shifted significantly; Figure 5 It can be seen that P a I b Sn c Te d The XRD peak of the catalyst shifts to a small angle compared to the pure PISn catalyst, which further proves that Te is doped into the PISn catalyst. Because the Te atomic radius is large, the doping increases the interplanar spacing of the PISn catalyst, causing the peak of the doped PISn catalyst to shift to a small angle; this proves that Te is successfully doped into PISn, and the doping element Te reacts with some phosphorus atoms in the catalyst to form P-Te bonds, exposing the PISn catalyst to more P vacancies and active sites, which is more conducive to the P4 molecule adsorption reaction, thereby greatly improving the catalytic activity.

[0046] Figure 6 To utilize P a I b Sn c Te d Black phosphorus prepared by catalyst, Figure 7 The SEM image of the obtained black phosphorus shows that it has an obvious layered stacking structure. The obtained sample was characterized by XRD and Raman. Figure 7 and Figure 8 As shown, Figure 7 It can be seen that the sample has characteristic peaks of black phosphorus at 16.99°(020), 26.55°(021), 34.24°(040), and 52.26°(060), and the characteristic peaks are very sharp, indicating that its crystallization is better and it is orthorhombic black phosphorus. In addition to the characteristic peaks of black phosphorus, no peaks of other substances are found, indicating that the prepared black phosphorus has a high purity (purity 99.99%). Raman spectrum of black phosphorus is made. Figure 8We can see the Raman characteristic peaks of black phosphorus, which are A and B caused by the out-of-plane vibration mode. g 1 Peak (357.6cm -1 ) and in-plane vibration Peak (461.8cm -1 ), B 2g Peak (433.7cm -1 ), which once again proves that the use of P a I b Sn c Te d The catalyst produced black phosphorus, and no peaks of other substances appeared except the Raman characteristic peak of black phosphorus, which once again showed that the obtained black phosphorus was free of impurities.

[0047] Under the condition of keeping temperature at 535℃ for 30min, the yield of black phosphorus prepared by using this catalyst is 98.7%.

[0048] Comparative Example 1

[0049] A method for preparing a PISn black phosphorus catalyst, comprising the following steps:

[0050] (1) Weigh 0.68 g of phosphorus, 1.252 g of tin tetraiodide, and 2.62 g of tin respectively, grind them, and mix them evenly.

[0051] (2) Place the evenly mixed materials into a quartz tube and seal the tube opening with a sealing film.

[0052] (3) Remove the sealing film and quickly vacuum-seal the quartz tube.

[0053] (4) The quartz tube was heated using a tubular furnace with a pre-set heating and cooling program. The specific program was as follows: at room temperature, the temperature was raised to 550°C at a rate of 5°C / min, kept at that temperature for 120 minutes, then cooled to 500°C after 225 minutes, kept at that temperature for 120 minutes, and then heated to 550°C after 10 minutes, and kept at that temperature. The temperature was kept at 550°C and 500°C for 6 times, and finally cooled to room temperature naturally.

[0054] (5) After the reaction is completed, a bulk PISn compound is obtained, which is taken out and ground into powder to obtain a PISn catalyst.

[0055] The obtained catalyst was used to prepare black phosphorus. Under the condition of keeping the temperature at 535°C for 30 minutes, the black phosphorus yield was 14.7%. Under the condition of keeping the temperature at 535°C for 8 hours, the black phosphorus yield was 98.1%.

[0056] By comparison, it can be seen that the P prepared by the present invention a I b Snc Te d The catalyst has high catalytic activity when used in the preparation of black phosphorus.

[0057] Example 2

[0058] A method for preparing a highly active doped modified black phosphorus catalyst P a I b Sn c Te d The specific steps are as follows:

[0059] (1) Phosphorus, tin tetraiodide, tin, and tellurium were weighed in a mass ratio of 1:2:4:0.7, ground, and mixed evenly.

[0060] (2) Place the evenly mixed materials into a quartz tube and seal the tube opening with a sealing film.

[0061] (3) Remove the sealing film and quickly vacuum-seal the quartz tube.

[0062] (4) The quartz tube was heated in a tubular furnace with a preset heating and cooling program. The specific program was as follows: at room temperature, the temperature was raised to 650°C at a rate of 5°C / min, kept at this temperature for 300 min, and then cooled. The heating program was stopped at the holding temperature, and the tubular furnace was opened to cool to room temperature within 5 min.

[0063] (5) After the reaction is completed, the block P is obtained a I b Sn c Te d The compound is taken out and ground into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Te d .

[0064] The obtained catalyst was used to prepare black phosphorus. Under the condition of keeping the temperature at 535°C for 30 minutes, the black phosphorus yield was 98.2%.

[0065] Example 3

[0066] A method for preparing a highly active doped modified black phosphorus catalyst P a I b Sn c Te d The specific steps are as follows:

[0067] (1) Phosphorus, tin tetraiodide, tin, and tellurium were weighed in a mass ratio of 1:2:4:3, ground, and mixed evenly.

[0068] (2) Place the evenly mixed materials into a quartz tube and seal the tube opening with a sealing film.

[0069] (3) Remove the sealing film and quickly vacuum-seal the quartz tube.

[0070] (4) The quartz tube was heated using a tubular furnace with a pre-set heating and cooling program. The specific program was as follows: at room temperature, the temperature was raised to 450°C at a rate of 5°C / min, kept at that temperature for 1800 min, and then cooled. The heating program was stopped at the holding temperature, and the tubular furnace was opened to allow the temperature to drop to room temperature within 5 min.

[0071] (5) After the reaction is completed, the block P is obtained a I b Sn c Te d The compound is taken out and ground into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Te d .

[0072] The obtained catalyst was used to prepare black phosphorus. Under the condition of keeping the temperature at 535°C for 30 minutes, the black phosphorus yield was 98.0%.

[0073] Comparative Example 3

[0074] A method for preparing a highly active doped modified black phosphorus catalyst P a I b Sn c Au d The specific steps are as follows:

[0075] (1) Phosphorus, tin tetraiodide, tin, and gold were weighed in a mass ratio of 1:2:4:0.35, ground, and mixed evenly.

[0076] (2) Place the evenly mixed materials into a quartz tube and seal the tube opening with a sealing film.

[0077] (3) Remove the sealing film and quickly vacuum-seal the quartz tube.

[0078] (4) The quartz tube was heated using a tubular furnace with a pre-set heating and cooling program. The specific program was as follows: at room temperature, the temperature was raised to 550°C at a rate of 5°C / min, kept at that temperature for 1800 min, and then cooled. The heating program was stopped at the holding temperature, and the tubular furnace was opened to allow the temperature to drop to room temperature within 5 min.

[0079] (5) After the reaction is completed, the block P is obtained a I b Sn cGa d The compound is taken out and ground into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Ga d .

[0080] The obtained catalyst was used to prepare black phosphorus. Under the condition of keeping the temperature at 535°C for 30 minutes, the black phosphorus yield was 40.3%.

[0081] Comparative Example 2

[0082] A method for preparing a highly active doped modified black phosphorus catalyst P a I b Sn c Ge d The specific steps are as follows:

[0083] (1) Phosphorus, tin tetraiodide, tin, and germanium were weighed in a mass ratio of 1:2:4:0.35, ground, and mixed evenly.

[0084] (2) Place the evenly mixed materials into a quartz tube and seal the tube opening with a sealing film.

[0085] (3) Remove the sealing film and quickly vacuum-seal the quartz tube.

[0086] (4) The quartz tube was heated using a tubular furnace with a pre-set heating and cooling program. The specific program was as follows: at room temperature, the temperature was raised to 550°C at a rate of 5°C / min, kept at that temperature for 1800 min, and then cooled. The heating program was stopped at the holding temperature, and the tubular furnace was opened to allow the temperature to drop to room temperature within 5 min.

[0087] (5) After the reaction is completed, the block P is obtained a I b Sn c Ge d The compound is taken out and ground into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Ge d .

[0088] The obtained catalyst was used to prepare black phosphorus. Under the condition of keeping the temperature at 535°C for 30 minutes, the black phosphorus yield was 70%.

Claims

1. Use of a highly active catalyst for preparing black phosphorus, characterized in that: The catalyst is P a I b Sn c Te d , the value of a is 10~30, the value of b is 5~15, the value of c is 15~30, and the value of d is 1~30.

2. Use of the highly active catalyst according to claim 1 for preparing black phosphorus, characterized in that: The specific steps include: (1) Weigh phosphorus, tin tetraiodide, tin, and tellurium, grind, and mix the four materials uniformly; wherein the mass ratio of phosphorus, tin tetraiodide, tin, and tellurium is 1:(1-5):(3-10):(0.1-10); (2) placing the materials uniformly mixed in step (1) into a reactor and sealing the tube opening with a sealing film; (3) removing the sealing film from the reactor in step (2) and quickly evacuating the reactor or filling it with inert gas to seal it; (4) heating the reactor sealed in step (3) using a heater with a pre-set heating and cooling program; (5) After the reaction is completed, open the reactor in step (4) to obtain a block P a I b Sn c Te d , take it out and grind it into powder to obtain the doped modified black phosphorus catalyst P a I b Sn c Te d .

3. The use of the highly active catalyst according to claim 2 for preparing black phosphorus, characterized in that: The mass feed ratio of phosphorus, tin tetraiodide, tin and tellurium is 1:(2-3):(4-6):(0.3-3).

4. The use of the highly active catalyst according to claim 2 for preparing black phosphorus, characterized in that: The tin and tellurium elements in step (1) are in the form of any one of powder, foil, granule or block, or a combination of at least two of them.

5. The use of the highly active catalyst according to claim 2 for preparing black phosphorus, characterized in that: The reactor described in step (2) is any one of a quartz reactor, a ceramic reactor or a metal reactor.

6. Use of the highly active catalyst according to claim 2 for preparing black phosphorus, characterized in that: The inert gas in step (3) includes any one of argon and helium.

7. Use of the highly active catalyst according to claim 2 for preparing black phosphorus, characterized in that: The heater described in step (4) is a resistance heater, an electromagnetic heater or a microwave heater.

8. Use of the highly active catalyst according to claim 2 for preparing black phosphorus, characterized in that: The heating treatment procedure of step (4) is as follows: at room temperature, the temperature is raised to 450-650°C over 50-300 minutes, then kept at this temperature for 120-1800 minutes, and then cooled to room temperature at a cooling rate of 1-100°C / min.

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