METHOD OF PREPARING BLACK PHOSPHORUS CRYSTALS

Abstract

Provided is a method of preparing black phosphorus crystal. First, one area of a double-opening reactor is used as the feedstock area, the other area is used as the nucleation area, and the middle area is used as a transition section, and the feedstock area is sealed, the phosphorus feedstock and the transport agent are weighed and placed inside the feedstock area under an inert atmosphere, then the nucleation area is sealed, the first step of heating reaction is performed in the reactor through an optimized temperature-control program, when the reaction is complete, monoclinic phosphorus crystals are prepared in the feedstock area. Then the nucleation area of the reactor is started, the weighed catalyst is placed inside the feedstock area under an inert atmosphere, and the nucleation area is sealed, and then the second step of a heating reaction is performed in the reactor through an optimized temperature-control program.

Claims

1. A method for preparing black phosphorus crystals, comprising the following steps: (1) in an inert atmosphere weighting and placing phosphorus feedstock and transport agent inside a feedstock area of a sealed reactor, and performing a first step of heating reaction on the feedstock area and a nucleation area of the sealed reactor through a temperature-control program; (2) when the first step of heating reaction is complete, preparing monoclinic phosphorus crystals in the feedstock area; then adding the catalyst continuously into the feedstock area of the sealed reactor, and then performing a second step of heating reaction on the feedstock area and nucleation area of the sealed reactor through a temperature-control program; (3) when the second step of heating reaction is complete, preparing the black phosphorus crystals in the nucleation area.

2-5. (canceled)

6. The method for preparing black phosphorus crystals according to claim 1, wherein the phosphorus feedstock in step (1) is yellow phosphorus or amorphous red phosphorus or a combination of both.

7. The method for preparing black phosphorus crystals according to claim 1, wherein the transport agent in step (1) is any one of I.sub.2, SnI.sub.4, SnI.sub.2, PbI.sub.2, NH.sub.4I, BiI.sub.3, PI.sub.3, SnCl.sub.2, SnBr.sub.2 or a combination of at least two of them, and the purity of the transport agent is 95% or more.

8. The method of preparing black phosphorus crystals according to claim 1, wherein a mass feed ratio of the phosphorus feedstock and the transport agent in step (1) is 100:0.12.

9. The method of preparing black phosphorus crystals according to claim 1, wherein in the temperature control program in step (1) at room temperature, a temperature of the feedstock area is increased to 280320 C. by 0.51 h, held for 612 h, and then reduced to the room temperature by 12 h; temperature of the nucleation area was increased to 320340 C. by 0.51 h, held for 612 h, and then reduced to room temperature by 12 h.

10. The method of preparing black phosphorus crystals according to claim 9, wherein in the temperature control program in step (1), the temperature control program of the feedstock area and the nucleation area is synchronized, and the temperature of the nucleation area is always 2040 C. higher than the temperature of the feedstock area until it is reduced to room temperature.

11. The method for efficiently preparing black phosphorus crystals according to claim 1, wherein the catalyst in step (2) is any one or a combination of at least two of Sn, Pb, In, Bi, Cd, or an alloy containing any one or a combination of at least two elements of Sn, Pb, In, Bi, Cd, and the purity of the catalyst is 98% or more.

12. The method of preparing black phosphorus crystals according to claim 11, wherein the mass feed ratio of the phosphorus feedstock and the catalyst in step (2) is 100:0.24.

13. The method for preparing black phosphorus crystals according to claim 1, wherein the temperature-control program in step (2) is as follows: at room temperature, the temperature of the feedstock area is increased to 450-480 C. by 0.51 h, held for 612 h, and then reduced to room temperature by 24 h; the temperature of the nucleation area is increased to 440460 C. by 0.51 h, held for 612 h, and then reduced to room temperature by 24 h.

14. The method of preparing black phosphorus crystals according to claim 1, wherein in the temperature control program in step (1), the temperature-control program of the feedstock area, and the nucleation area is synchronized, and the temperature of the feedstock area is always 1040 C. higher than the temperature of the nucleation area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 shows a physical diagram of the used amorphous red phosphorus and the prepared monoclinic phosphorus in Example 1.

[0047] FIG. 2 shows the X-ray diffraction spectra of the used amorphous red phosphorus and the prepared monoclinic phosphorus in Example 1.

[0048] FIG. 3 shows the TG and DTG spectra of the used amorphous red phosphorus and the prepared monoclinic phosphorus in Example 1.

[0049] FIG. 4 shows a physical diagram of the black phosphorus crystals prepared in Example 1.

[0050] FIG. 5 shows the X-ray diffraction spectrum of the black phosphorus crystals prepared in Example 1.

[0051] FIG. 6 shows a physical diagram of the black phosphorus crystals prepared in Example 4.

[0052] FIG. 7 shows a physical diagram of the black phosphorus crystals prepared in Example 5.

[0053] FIG. 8 shows a physical diagram of the black phosphorus crystals prepared in Example 6.

DETAILED DESCRIPTION

[0054] For a better understanding of the present invention, the present invention is further illustrated below in connection with specific embodiments and the accompanying drawings, but the present invention is not limited to the following embodiments.

[0055] The double-opening reactor of the present invention is a customized device, the customized enterprise is Yantai Artisan Machinery Technology Co and the device model is ATS-BP02.

Example 1

A method of preparing black phosphorus crystals with low energy consumption and high efficiency, including the following preparation steps: [0056] (1) One area of a stainless steel double-opening reactor was used as the feedstock area and the other area as the nucleation area, the middle section as the transition area, and the feedstock area of the reactor was sealed. [0057] (2) Under the nitrogen inert atmosphere, 160 g of amorphous red phosphorus and 1.28 g of transport agent I.sub.2 were weighed and placed inside the feedstock area, and the nucleation area was sealed, and then the first step of heating reaction was carried out in the feedstock area and the nucleation area of the reactor through a temperature-controlled program, which was as follows: under the room temperature, the temperature of the feedstock area was increased to 300 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h, the temperature of the transition area was increased to 315 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the nucleation area was increased to 330 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 30 C. higher than that of the feedstock area; the temperature of the transition area was between them, and it was always 17.5 C. higher than that of the feedstock area, and 12.5 C. lower than that of the nucleation area until it was reduced to room temperature. [0058] (3) When the reaction was complete, the monoclinic phosphorus crystals were prepared at the feedstock area. [0059] (4) Starting the nucleation area of the reactor, under the nitrogen inert atmosphere, in the feedstock area including the monoclinic crystals of step (3), 2.4 g of catalyst Sn were placed inside the feedstock area, and the nucleation area was sealed, and then the second step of the heating reaction was carried out in the feedstock area and the nucleation area of the reactor through the temperature-controlled program, specifically as follows: under room temperature, the temperature of the feedstock area was increased to 465 C. by 0.8 h, held for 9 h, then reduced to room temperature by 3 h, the transition area temperature was increased to 460 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h; the nucleation area temperature was increased to 450 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area was always 15 C. higher than that of the nucleation area; the temperature of the transition area was between them, and it was always 7.5 C. lower than that of the feedstock area, and 17.5 C. higher than that of the nucleation area until it was reduced to room temperature. [0060] (5) When the reaction is complete, high quality black phosphorus crystals were finally prepared of the nucleation area.

[0061] FIG. 1 showed a physical diagram of the used amorphous red phosphorus and the prepared monoclinic phosphorus in Example 1, from which it can be seen that the monoclinic phosphorus is lighter in color compared to the amorphous red phosphorus, and is a loose powdery crystal, which is mainly related to the activation of the phosphorus feedstock by the transport agent FIG. 2 showed the X-ray diffraction spectra of the used amorphous red phosphorus and the prepared monoclinic phosphorus in Example 1, from which it can be seen that the amorphous red phosphorus has no obvious diffraction peaks, while the diffraction peaks of the monoclinic phosphorus have a higher intensity and are well-matched with the standard PDF card, indicating that the prepared monoclinic phosphorus is well-crystallized, the black phosphorus has a high purity. FIG. 3 showed the TG and DTG spectra of the used amorphous red phosphorus and the prepared monoclinic phosphorus in Example 1, from which it can be seen that the volatilization temperature of the amorphous red phosphorus is about 500 C., and the maximum weight loss rate temperature is 510 C., whereas the volatilization temperature of the monoclinic phosphorus is only 400 C., and the maximum weight loss rate temperatures are only 430 C. and 500 C., and under the same conditions, the heat loss of monoclinic phosphorus is about 30% lower than that of amorphous red phosphorus, which indicates that monoclinic phosphorus has a lower volatilization temperature and volatilization rate, and the use of monoclinic phosphorus feedstock can effectively reduce the temperature and pressure required for the second step of the black phosphorus preparation reaction. FIG. 4 showed a physical diagram of the black phosphorus crystals prepared in Example 1, from which it can be seen that the black phosphorus crystals appear as massive crystals having a metallic luster, weighing 157.7 g, with a total yield of 98.16%. FIG. 5 showed the X-ray diffraction spectrum of the black phosphorus crystals prepared in Example 1, from which it can be seen that the sample exhibits typical characteristic peaks of black phosphorus and no other miscellaneous peaks appeared, which indicates that the prepared black phosphorus crystals are well crystallized and has a high purity. The three strong characteristic peaks match the crystal faces of (020), (040) and (060) of the black phosphorus crystals respectively.

Example 2

The method and steps are the same as in Example 1, except that in step (2), the temperature control program of the feedstock area, transition area and nucleation area of the reactor was adjusted as follows: under the room temperature, the temperature of the feedstock area is increased to 280 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the transition area is increased to 300 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5h; and the temperature of the nucleation area is increased to 330 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 50 C. higher than that of the feedstock area, while the temperature of the transition area was between them, and it was always 20 C. higher than that of the feedstock area, and 30 C. lower than that of the nucleation area until it was reduced to room temperature. Due to the large temperature difference, monoclinic phosphorus could not be prepared, and the product was still granular amorphous red phosphorus.

[0062] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 290 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the transition area was increased to 310 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; and the temperature of the nucleation area was increased to 330 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and nucleation area temperature is always 40 C. higher than that of the feedstock area, the transition area of the temperature between them, and always 20 C. higher than the temperature of the feedstock area, 20 C. lower than the temperature of the nucleation area, until it was reduced to room temperature, and other conditions were the same as in Example 1. When the temperature difference was controlled in a suitable range, the monoclinic phosphorus can be obtained with the morphology and characteristics similar to that of Example 1, the total yield of monoclinic phosphorus can be up to 99.9%.

[0063] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 310 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the transition area was increased to 320 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; and the temperature of the nucleation area was increased to 330 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 20 C. higher than that of the feedstock area, the temperature of the transition area was between them, and always 10 C. higher than that of the feedstock area, 10 C. lower than that of the nucleation area temperature, until it was reduced to room temperature, and other conditions were the same as in Example 1. When the temperature difference was controlled in a suitable range, the monoclinic phosphorus can be obtained with the morphology and characteristics similar to that of Example 1, the total yield of monoclinic phosphorus can be up to 99.9%.

[0064] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 320 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the transition area was increased to 325 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the nucleation area was increased to 330 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 10 C. higher than that of the feedstock area, the transition area temperature between them, and was always 5 C. higher than that of the feedstock area, 5 C. lower than that of the nucleation area, until it was reduced to room temperature, and other conditions were the same as in Example 1. Since the temperature difference was too small, the monoclinic phosphorus cannot be prepared, the product was still a granular amorphous red phosphorus.

[0065] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 320 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the transition area was increased to 320 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h; the temperature of the nucleation area was increased to 320 C. by 0.6 h, held for 9 h, and then reduced to room temperature by 1.5 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and there was no temperature difference between the feedstock area, transition area and nucleation area until it was reduced to room temperature, and other conditions were the same as in Example 1. Due to the lack of a temperature difference, the monoclinic phosphorus cannot be prepared, and the product was still granular amorphous red phosphorus.

Example 3

The method and steps are the same as in Example 1, except that in step (4), the temperature control program of the feedstock area, the transition area and the nucleation area of the reactor was adjusted as follows: under the room temperature, the temperature of the feedstock area was increased to 450 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h; the temperature of the transition area was increased to 450 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h; and the temperature of the nucleation area was increased to 450 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and there was no temperature difference between the feedstock area, transition area and nucleation area until the temperature was reduced to room temperature. Due to the small temperature difference, the black phosphorus cannot be prepared, and the product was still powdery monoclinic phosphorus crystals, which cannot be transformed to black phosphorus crystals.

[0066] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 455 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h. The temperature of the transition area was increased to 452.5 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h. The temperature of the nucleation area was increased to 450 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h. The temperature-control programs for the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area was always 5 C. higher than that of the nucleation area. The temperature of the transition area was between them, and was always 2.5 C. lower than that of the feedstock area, 2.5 C. higher than that of the nucleation area, until it was reduced to room temperature, and other conditions are the same as in Example 1. Since the temperature difference is too small, the black phosphorus cannot be prepared, and the product was still powdery monoclinic phosphorus crystals, which cannot be transformed to black phosphorus crystals.

[0067] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 475 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h; the temperature of the transition area was increased to 462.5 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h; the temperature of the nucleation area was increased to 450 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area was always 25 C. higher than that of the nucleation area. The temperature of the transition area was between them, and was always 12.5 C. lower than that of the feedstock area and 12.5 C. higher than that of the nucleation area until it was reduced to room temperature, and other conditions were the same as in Example 1. Due to the appropriate temperature difference, the black phosphorus can be prepared, which was basically the same in morphology as in Example 1, and weighed 157.02 g with the total yield of 98.13%.

[0068] In another embodiment of the present invention, under the room temperature, the temperature of the feedstock area was increased to 480 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h, the temperature of the transition area was increased to 460 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h; the temperature of the nucleation area was increased to 440 C. by 0.8 h, held for 9 h, and then reduced to room temperature by 3 h. The temperature control programs for the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area is always 40 C. higher than that of the nucleation area. The temperature of the transition area was between them, and was always 20 C. lower than that of the feedstock area and 20 C. higher than that of the nucleation area until it was reduced to room temperature, and other conditions were the same as in Example 1. Due to the appropriate temperature difference, the black phosphorus can be prepared, which was basically the same in morphology as in Example 1, the weight of which was 159.1 g, and the total yield was 99.44%.

Example 4

A method of preparing black phosphorus crystals with low energy consumption and high efficiency, including the following preparation steps: [0069] (1) One area of a stainless steel double-opening reactor was used as the feedstock area and the other area as the nucleation area, the middle section as the transition area, and the feedstock area of the reactor was sealed. [0070] (2) Under the nitrogen inert atmosphere, 270 g of amorphous red phosphorus and 0.27 g of transport agent SnI.sub.4 were weighed and placed inside the feedstock area and the nucleation area was sealed, and then the first step of heating reaction was carried out in the feedstock area and the nucleation area of the reactor through a temperature-controlled program, which was as follows: under the room temperature, the temperature of the feedstock area was increased to 280 C. by 0.5 h, held for 6 h, and then reduced to room temperature by 1 h; the temperature of the transition area was increased to 300 C. by 0.5 h, held for 6 h, and then reduced to room temperature by 1 h; the temperature of the nucleation area was increased to 320 C. by 0.5 h, held for 6 h, and then reduced to room temperature by 1 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 40 C. higher than that of the feedstock area; the temperature of the transition area was between them, and was always 20 C. higher than that of the feedstock area, 20 C. lower than that of the nucleation area, until it was reduced to room temperature. [0071] (3) When the reaction was complete, the monoclinic phosphorus crystals were prepared at the feedstock area. [0072] (4) Starting the nucleation area of the reactor, and under the nitrogen inert atmosphere, in the feedstock area including the monoclinic crystals of step (3), 0.54 g of catalyst Bi were placed inside the feedstock area and the nucleation area was sealed, and then the second step of the heating reaction was carried out in the feedstock area and the nucleation area of the reactor through the temperature-controlled program, specifically as follows: under the room temperature, the temperature of the feedstock area was increased to 450 C. by 0.5 h, and then held for 6 h, and then reduced to room temperature by 2 h; the temperature of the transition area was increased to 445 C. by 0.5 h, held for 6 h, and then reduced to room temperature by 2 h; the temperature of the nucleation area was increased to 440 C. by 0.5 h, held for 6 h, and then reduced to room temperature by 2 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area was always 10 C. higher than that of the nucleation area. The temperature of the transition area was between them, and was always 5 C. lower than that of the feedstock area and 5 C. higher than that of the nucleation area until it was reduced to room temperature. [0073] (5) When the reaction was complete, high quality black phosphorus crystals were finally prepared in the nucleation area.

[0074] FIG. 6 showed a physical diagram of the black phosphorus crystals prepared in Example 4, from which it can be seen that the black phosphorus crystals appeared as lumpy crystals having a metallic luster, weighing 269.1 g, with a total yield of 99.67%.

Example 5

A method of preparing black phosphorus crystals with low energy consumption and high efficiency, including the following preparation steps: [0075] (1) One area of the Hastelloy double-opening reactor was used as the feedstock area, the other area as the nucleation area, and the middle section as the transition area, and the feedstock area of the reactor was sealed. [0076] (2) Under a nitrogen inert atmosphere, 380 g of yellow phosphorus and 7.6 g of transport agent Bils were weighed and placed inside the feedstock area, and the nucleation area was sealed, and then the first step of heating reaction was carried out in the feedstock area and the nucleation area of the reactor through the temperature-controlled program, which was as follows: at the room temperature, the temperature of the feedstock area was increased to 320 C. by 1 h, holding 12 h, and then reduced to room temperature by 2 h; the temperature of the transition area was increased to 330 C. by 1 h, held for 12 h, and then reduced to room temperature by 2 h; the temperature of the nucleation area was increased to 330 C. by 1 h, holding 12 h, and then reduced to room temperature by 2 h. The temperature control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 20 C. higher than that of the feedstock area; the temperature of the transition area was between them, and was always 10 C. higher than that of the feedstock area, and 10 C. lower than that of the nucleation area, until it was reduced to room temperature. [0077] (3) When the reaction was complete, the monoclinic phosphorus crystals were prepared in the feedstock area. [0078] (4) Starting the nucleation area of the reactor, and under the nitrogen inert atmosphere, in the feedstock area including the monoclinic crystals of step (3), 15.2 g of catalyst In were placed inside the feedstock area, and the nucleation area was sealed, and then the second step of the heating reaction was carried out in the feedstock area and the nucleation area of the reactor through the temperature-controlled program, specifically as follows: under the room temperature, the temperature of the feedstock area was increased to 480 C. by 1 h, held for 12 h, and then reduced to room temperature by 4 h; the temperature of the transition area was increased to 470 C. by 1 h, held for 12 h, and then reduced to room temperature by 4 h; the temperature of the nucleation area was increased to 460 C. by 1 h, held for 12 h, and then reduced to room temperature by 4 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area was always 20 C. higher than that of the nucleation area, the temperature of the transition area was between them, and it was always 10 C. lower than that of the feedstock area, and 10 C. higher than that of the nucleation area until it was reduced to room temperature. [0079] (5) When the reaction was complete, high quality black phosphorus crystals were finally prepared in the nucleation area.

[0080] FIG. 7 shows a physical diagram of the black phosphorus crystals prepared in Example 5, from which it can be seen that the black phosphorus crystals appear as massive crystals with a metallic luster, weighing 373.0 g, with a total yield of 98.16%.

Example 6

A method of preparing black phosphorus crystals with low energy consumption and high efficiency, including the following preparation steps: [0081] (1) One area of a nickel alloy double-opening reactor was used as the feedstock area and the other area as the nucleation area, the middle section as the transition area, and the feedstock area of the reactor was sealed. [0082] (2) Under the argon inert atmosphere, 1020 g of yellow phosphorus and 8.16 g of transport agent PI.sub.3 were weighed and placed inside the feedstock area and the nucleation area was sealed, and then the first step of heating reaction was carried out on the feedstock area and the nucleation area of the reactor through the temperature-controlled program, which was as follows: under the room temperature, the temperature of the feedstock area was increased to 320 C. by 1 h, held for 12 h, and then reduced to the room temperature by 2 h; the temperature of the transition area was increased to The temperature of the transition area was increased to 330 C. for 1 h, held for 12 h, and then reduced to room temperature for 2 h; the temperature of the nucleation area was increased to 340 C. for 1 h, held for 12 h, and then reduced to room temperature for 2 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the nucleation area was always 20 C. higher than that of the feedstock area; the temperature of the transition area was between them, and was always 10 C. higher than that of the feedstock area, 10 C. lower than that of the nucleation area, until it was reduced to room temperature. [0083] (3) When the reaction is complete, the monoclinic phosphorus crystals were prepared in the feedstock area. [0084] (4) Starting the nucleation area of the reactor, under argon inert atmosphere, in the feedstock area including the monoclinic crystals of step (3), 15.3 g of catalyst Sn were placed inside the feedstock area, and the nucleation area was sealed, and then the second step of the heating reaction was carried out in the feedstock area and the nucleation area of the reactor through the temperature-controlled program, specifically as follows: under the room temperature, the temperature of the feedstock area was increased to 480 C. through 1 h, held for 12 h, then reduced to room temperature by 4 h, the temperature of the transition area was increased to 470 C. through 1 h, held for 12 h, then reduced to room temperature by 4 h; the temperature of the nucleation area was increased to 460 C. through 1 h, held for 12 h, then reduced to room temperature by 4 h. The temperature-control programs of the feedstock area, transition area and nucleation area were synchronized, and the temperature of the feedstock area was always 20 C. higher than that of the nucleation area; the temperature of the transition area was between them, and it was always 10 C. lower than that of the feedstock area, and 10 C. higher than that of the nucleation area until it was reduced to room temperature. [0085] (5) When the reaction was complete, high quality black phosphorus crystals were finally prepared in the nucleation area.

[0086] FIG. 8 shows a physical diagram of the black phosphorus crystals prepared in Example 6, from which it can be seen that the black phosphorus crystals appear as massive crystals having a metallic luster, weighing 1011.4 g, with a total yield of 99.16%.