A porous red phosphorus nanosphere with tunable pore size and its preparation method
By using commercial red phosphorus and ethylenediamine to prepare porous red phosphorus nanospheres, the problems of high preparation cost and impurity introduction in existing technologies have been solved, realizing low-cost, impurity-free red phosphorus nanospheres with tunable pore size, which are suitable for energy materials and catalytic chemistry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI UNIV
- Filing Date
- 2023-07-27
- Publication Date
- 2026-06-30
Smart Images
Figure CN116715206B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanomaterials technology and relates to a porous red phosphorus nanosphere with tunable pore size and its preparation method. Background Technology
[0002] Red phosphorus has emerged as a promising material in many fields in recent years, primarily due to its abundant and inexpensive mineral resources. Secondly, its superior inherent properties offer advantages in various areas. For instance, red phosphorus has a wide absorption range for visible light and is easily modified to create catalytic structures of different dimensions, making it a potential material for photocatalysis. It is being extensively studied in areas such as photocatalytic water splitting and organic matter degradation. It is also used as a photosensitizer in the biomedical field for cancer treatment. Commercial red phosphorus, however, is limited in its applications due to its predominantly micron-sized and unevenly distributed particles with few active sites. Nevertheless, numerous studies have shown that structural morphology significantly impacts its performance; for example, nanostructuring the material, with its larger surface area, provides more reaction sites and enhances its performance. However, red phosphorus is chemically stable and poorly soluble in solvents, making structural reshaping of micron-sized, irregular red phosphorus very difficult. While some methods exist for nanostructuring red phosphorus, such as vaporizing and then condensing commercial red phosphorus to obtain nanoparticles or nanorods, and using simple mechanical ball milling to obtain two-dimensional sheet-like red phosphorus, achieving more complex morphological structures remains challenging. Wet chemical methods can flexibly prepare a variety of complex structures, but the preparation cost is high and it is easy to introduce organic impurities that are difficult to remove, such as surfactants, which makes it difficult to commercialize.
[0003] Patent CN114314535A discloses a porous red phosphorus nanosphere and its preparation method. First, phosphorus triiodide is added to iodobenzene and stirred until homogeneous to obtain mixture A. Then, hexadecylammonium bromide is added to ethylene glycol and stirred until homogeneous to obtain mixture B. Next, mixture A is added dropwise to mixture B and stirred to obtain a reaction solution. The reaction solution is then centrifuged, and the centrifuged product is washed with a mixed solvent and vacuum dried. The dried precursor is then added to ultrapure water for a hydrothermal reaction. The product is centrifuged, washed, and vacuum dried to obtain porous red phosphorus nanospheres. However, this patent first prepares red phosphorus nanoparticles under the control of a surfactant, and then uses a hydrothermal method to prepare the red phosphorus nanoparticles into a porous structure. The participation of organic morphology control agents in the preparation process introduces impurities that are difficult to remove. Furthermore, phosphorus triiodide, as a phosphorus source, is expensive, and currently, phosphorus triiodide products are mainly sourced from foreign manufacturers, resulting in long processing times and unstable supply. Summary of the Invention
[0004] The purpose of this invention is to overcome at least one of the defects of the prior art and provide a porous red phosphorus nanosphere with adjustable pore size and its preparation method. This invention greatly reduces the preparation cost, and porous red phosphorus nanospheres with adjustable pore size can be directly obtained through solvothermal or hydrothermal reaction. This process does not require any template or morphology control agent.
[0005] The objective of this invention can be achieved through the following technical solutions:
[0006] One of the technical solutions of the present invention is to provide a method for preparing porous red phosphorus nanospheres with tunable pore size, the method comprising the following steps:
[0007] (1) Preparation of precursor solution:
[0008] Red phosphorus was added to the first solvent and stirred evenly before being placed in a hydrothermal reactor. After a solvothermal reaction, a precursor solution was obtained.
[0009] (2) Preparation of precursor nanoparticles:
[0010] The precursor solution was added to the second solvent, stirred to form a precipitate, and dried to obtain precursor nanoparticles.
[0011] (3) Preparation of porous red phosphorus nanospheres by hydrothermal or solvothermal methods:
[0012] After adding the precursor nanoparticles to a third hydrothermal solvent or a fourth solvothermal solvent, the mixture is placed in a hydrothermal reactor. After hydrothermal or solvothermal reaction, the product is washed, centrifuged, and vacuum dried to obtain porous red phosphorus nanospheres.
[0013] Further, in step (1), the first solvent includes ethylenediamine, and the ratio of red phosphorus to the first solvent is (400-1200mg):(40-70mL).
[0014] As a preferred technical solution, the first solvent in step (1) includes anhydrous ethylenediamine.
[0015] As a preferred technical solution, the ratio of red phosphorus to the first solvent in step (1) is (800-1000mg):(50-70mL).
[0016] As a preferred technical solution, the stirring in step (1) is carried out in a sealed manner, the stirring time is 30-60 min, the temperature is room temperature, and the speed is 1000-1500 rpm.
[0017] Furthermore, in step (1), the solvothermal temperature is 120-160℃ and the isothermal time is 8-24h.
[0018] As a preferred technical solution, the solvothermal temperature in step (1) is 120-140℃ and the constant temperature time is 12-24h.
[0019] Furthermore, in step (2), the second solvent includes ethanol, and the volume ratio of the precursor solution to the second solvent is 1:(2-6).
[0020] As a preferred technical solution, the concentration of the second solvent in step (2) is 90-99.9%.
[0021] As a preferred technical solution, the concentration of the second solvent in step (2) is 99.9%.
[0022] As a preferred technical solution, the volume ratio of the precursor solution to the second solvent in step (2) is 1:(2-4).
[0023] As a preferred technical solution, the stirring time in step (2) is 30-120 min, the temperature is room temperature, and the speed is 1000-1500 rpm.
[0024] Furthermore, the third hydrothermal solvent in step (3) includes water.
[0025] Furthermore, in step (3), the hydrothermal temperature is 160-200℃ and the constant temperature time is 1-8h.
[0026] As a preferred technical solution, the hydrothermal temperature in step (3) is 180-200℃ and the constant temperature time is 1-5h.
[0027] Furthermore, the fourth solvothermal solvent in step (3) includes ethylene glycol.
[0028] Furthermore, in step (3), the solvothermal temperature is 160-180℃ and the isothermal time is 1-8h.
[0029] As a preferred technical solution, the solvothermal temperature in step (3) is 170-180℃ and the constant temperature time is 1-5h.
[0030] Furthermore, the filling degree of the hydrothermal reactor in steps (1) and (3) is 40-70%.
[0031] As a preferred technical solution, in step (3), the hydrothermal or solvothermal product is washed twice with water and ethanol respectively, and the centrifugation speed is 4000-8000 rpm for 3-6 min.
[0032] One of the technical solutions of the present invention is to provide a porous red phosphorus nanosphere with adjustable pore size prepared by the method, wherein the porous red phosphorus nanosphere has a uniform size distribution, a particle diameter of 60-120 nm, and the pore size changes with the reaction time.
[0033] This invention uses inexpensive commercial red phosphorus as the phosphorus source and ethylenediamine as the nucleophile to carry out a solvothermal reaction. The resulting precursor solution is rapidly precipitated under the action of a large amount of ethanol to generate spherical precursor nanoparticles. Porous red phosphorus nanospheres with tunable pores are then prepared through hydrothermal or solvothermal reactions.
[0034] Compared with the prior art, the present invention has the following beneficial effects:
[0035] (1) This invention uses commercial red phosphorus as a phosphorus source, which greatly reduces the cost of wet chemical preparation of nano red phosphorus and the preparation operation is safe;
[0036] (2) This invention prepares porous nanospheres without templates without introducing morphology control agents, reducing preparation costs while avoiding the introduction of organic impurities such as surfactants;
[0037] (3) The porous red phosphorus nanospheres prepared by the present invention have a pore size that can be controlled and adjusted by constant temperature and time. The product has a uniform morphology and small particle size. The porous structure can give red phosphorus a larger specific surface area, provide rich pore structure and reduce the density of red phosphorus powder. It is suitable for energy materials and catalytic chemistry applications and other technical fields.
[0038] (4) The method of the present invention is fast, the synthesis equipment is simple, the cost is low, the yield is relatively high compared with other wet chemical methods, and the requirements for the synthesis environment are not high. Attached Figure Description
[0039] Figure 1 This is a transmission electron microscope (TEM) image of the precursor nanoparticles in Example 1 of the present invention;
[0040] Figure 2 The X-ray diffraction (XRD) patterns of porous red phosphorus nanospheres in Example 1 and the comparative example of the present invention are shown below.
[0041] Figure 3 The images shown are TEM images, selected area electron diffraction patterns, and pore size statistics of the porous red phosphorus nanospheres in Examples 1 and 2 of this invention.
[0042] Figure 4 The XRD patterns are shown in Embodiment 3 and the comparative example of the present invention.
[0043] Figure 5 These are TEM images and selected area electron diffraction patterns of the porous red phosphorus nanospheres in Examples 3 and 4 of this invention. Detailed Implementation
[0044] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0045] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.
[0046] Example 1:
[0047] A porous red phosphorus nanosphere with tunable pore size and its preparation method are as follows:
[0048] (1) Preparation of precursor solution:
[0049] 900 mg of commercial red phosphorus was added to 50 mL of anhydrous ethylenediamine. After stirring in a sealed container at 1000 rpm for 30 min at room temperature, the mixture was placed in a hydrothermal reactor with a filling degree of 50%. The solvothermal temperature was 120 °C and the constant temperature time was 24 h. After the solvothermal reaction, 50 mL of precursor solution was obtained.
[0050] (2) Preparation of precursor nanoparticles:
[0051] 50 mL of precursor solution was added to 100 mL of anhydrous ethanol, with a volume ratio of precursor solution to anhydrous ethanol of 1:2. The mixture was stirred at room temperature and 1000 rpm for 60 min to generate a precipitate. After drying, 100 mg of precursor nanoparticles were obtained.
[0052] (3) Preparation of porous red phosphorus nanospheres by hydrothermal method:
[0053] 100 mg of precursor nanoparticles were added to 50 mL of ultrapure water and placed in a hydrothermal reactor with a filling degree of 50%. The hydrothermal temperature was 180 °C and the constant temperature time was 1 h. After the hydrothermal reaction, the product was washed twice with ultrapure water and anhydrous ethanol, respectively. After centrifugation at 7000 rpm for 5 min, the product was dried under vacuum at -0.1 MPa to obtain porous red phosphorus nanospheres with a particle size of 60-90 nm. The pore size was concentrated in 8-9 nm, and the yield was 70 ± 5 mg. Compared with the preparation of porous red phosphorus nanospheres with phosphorus triiodide, the yield was greatly improved.
[0054] In step (3), the amount of solvent and precursor nanoparticles does not need to be in a specific ratio; it is only necessary to ensure the filling degree of the hydrothermal reactor.
[0055] Example 2:
[0056] A porous red phosphorus nanosphere with adjustable pore size and its preparation method are basically the same as those in Example 1, except that 1000 mg of commercial red phosphorus is used in step (1), the isothermal time is 3 h in step (3), and the pore size is concentrated in 10-12 nm.
[0057] Example 3:
[0058] A porous red phosphorus nanosphere with adjustable pore size and its preparation method are basically the same as those in Example 1, except that in step (1) 1000 mg of commercial red phosphorus is used, in step (2) the volume ratio of precursor solution to anhydrous ethanol is 1:4, in step (3) ultrapure water is replaced with 50 mL of anhydrous ethylene glycol, the solvothermal temperature is 170 °C, the constant temperature time is 1 h, and the obtained product has no obvious pores and is more porous than the product obtained by hydrothermal treatment in Example 1, with a particle size of 60-120 nm.
[0059] Example 4:
[0060] A porous red phosphorus nanosphere with adjustable pore size and its preparation method are basically the same as those in Example 3, except that the isothermal time in step (3) is 3h, and the product obtained has larger pores compared with the solvothermal isothermal time of 1h in Example 3.
[0061] Comparative example:
[0062] Commercial red phosphorus.
[0063] like Figure 1 As shown, the precursor of Example 1 has a nanosphere morphology with a particle size of 60-120 nm.
[0064] like Figure 2 As shown, the porous red phosphorus nanospheres prepared by the hydrothermal method in Example 1 are consistent with the X-ray diffraction (XRD) patterns of commercial red phosphorus, both showing broad characteristic diffraction peaks near 2θ = 15°, 30-35°, and 50°, exhibiting an amorphous structure.
[0065] like Figure 3 As shown in the transmission electron microscope (TEM) images, it can be seen that the hydrothermal method in Examples 1 and 2 can prepare porous nanospheres. The pore size statistics show that the pore size increases with hydrothermal time. The particle size of Example 1 is 60-90 nm, and the porous pore size is concentrated in 8-9 nm. The porous pore size of Example 2 is concentrated in 10-12 nm. The selected area electron diffraction pattern shows that the material has an amorphous structure, which is consistent with the XRD results.
[0066] like Figure 4 As shown, the porous red phosphorus nanospheres prepared by the solvothermal method in Example 3 are also consistent with the XRD pattern of commercial red phosphorus, exhibiting an amorphous structure.
[0067] like Figure 5As shown in the TEM images, it can be seen that the solvothermal methods in Examples 3 and 4 can prepare porous nanospheres. The longer the solvothermal time, the more obvious the pore size. The product obtained in Example 3 has no obvious pores and is more porous than the product obtained by hydrothermal treatment in Example 1, with a particle size of 60-120 nm. The product obtained in Example 4 has larger pores compared to the product obtained by solvothermal isothermal treatment in Example 3, which has a solvothermal isothermal time of 1 h. Selected area electron diffraction patterns show that the material has an amorphous structure, which is consistent with the XRD results.
[0068] In summary, this embodiment uses commercial red phosphorus as the phosphorus source and ethylenediamine as the nucleophile for a solvothermal reaction. It cleverly utilizes anhydrous ethanol to rapidly precipitate spherical precursor nanoparticles. Porous red phosphorus nanospheres with tunable pore size are then prepared via hydrothermal or solvothermal reactions, with the pore size increasing with reaction time. Furthermore, the morphology varies in different solvents; the product obtained by solvothermal reaction with ethylene glycol exhibits a more porous structure, which is related to the solvent properties. This embodiment reduces the cost of wet chemical methods for preparing red phosphorus nanospheres and provides a template-free and rapid preparation of porous red phosphorus nanospheres.
[0069] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A method for preparing porous red phosphorus nanospheres with tunable pore size, characterized in that, The method includes the following steps: (1) Preparation of precursor solution: Commercial red phosphorus was added to the first solvent and placed in a hydrothermal reactor. After a solvothermal reaction, a precursor solution was obtained. (2) Preparation of precursor nanoparticles: The precursor solution was added to the second solvent and stirred to generate a precipitate, thus obtaining precursor nanoparticles. (3) Preparation of porous red phosphorus nanospheres by hydrothermal or solvothermal methods: The precursor nanoparticles were added to a third solvent and placed in a hydrothermal reactor. After hydrothermal reaction, porous red phosphorus nanospheres were obtained. The hydrothermal temperature was 160-200 ℃, and the isothermal time was 1-8 h. or, After adding the precursor nanoparticles to the fourth solvent, the mixture was placed in a hydrothermal reactor. After a solvothermal reaction, porous red phosphorus nanospheres were obtained. The solvothermal temperature was 160-180 ℃ and the isothermal time was 1-8 h. The first solvent in step (1) includes ethylenediamine; In step (1), the solvothermal temperature is 120-160 ℃ and the isothermal time is 8-24 h; In step (2), the second solvent includes ethanol, and the volume ratio of the precursor solution to the second solvent is 1:(2-6); Commercial red phosphorus was used as the phosphorus source and ethylenediamine was used as the nucleophile for a solvothermal reaction. The precursor solution formed was rapidly precipitated into spherical precursor nanoparticles under the action of a large amount of ethanol. Porous red phosphorus nanospheres with adjustable pore size were prepared by hydrothermal or solvothermal methods. Without introducing morphology control agents, porous nanospheres were prepared without templates, thus avoiding the introduction of organic impurities from surfactants. The diameter of the porous red phosphorus nanospheres is 60-120 nm.
2. The method for preparing porous red phosphorus nanospheres with tunable pore size according to claim 1, characterized in that, In step (1), the ratio of red phosphorus to the first solvent is (400-1200 mg):(40-70 mL).
3. The method for preparing porous red phosphorus nanospheres with tunable pore size according to claim 1, characterized in that, The third solvent in step (3) includes water.
4. The method for preparing porous red phosphorus nanospheres with tunable pore size according to claim 1, characterized in that, The fourth solvent in step (3) includes ethylene glycol.
5. The method for preparing porous red phosphorus nanospheres with tunable pore size according to claim 1, characterized in that, In steps (1) and (3), the filling degree of the hydrothermal reactor is 40-70%.