A nano-flower porous carbon shell doped with single-atom tungsten and a preparation method thereof

Abstract

The application discloses a kind of nanoflower porous carbon shell doped with metal single-atom tungsten and a preparation method thereof, and belongs to the field of electromagnetic functional materials.The method of the present application comprises the following steps:Step 1, 3-aminopropyltriethoxysilane and flower-like silica are added to toluene, followed by heating treatment;Step 2, then ultrasonic dispersion in an aqueous solution of glacial acetic acid together with chitosan and sodium tungstate, stirring at room temperature, hydrothermal reaction;high-temperature carbonization under inert gas atmosphere;Step 3, then immersed in hydrofluoric acid.The preparation method of the present application has the characteristics of universality, simple process, high product preparation efficiency, etc.The prepared nanoflower porous carbon shell loaded with metal single-atom tungsten has a diameter of about 200 nm.The prepared nanoflower porous carbon shell loaded with metal single-atom tungsten exhibits excellent electromagnetic energy loss characteristics, and can be applied in the fields of electromagnetic stealth technology, communication, electromagnetic shielding, human health protection, intelligent electronic communication, etc.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic functional materials, specifically, it relates to a nano-flower-like porous carbon shell doped with tungsten single atoms and its preparation method. Background Technology

[0002] With the rapid development of science and technology and the global Internet of Things (IoT) smart information technology, the demand for advanced electromagnetic functional materials is becoming increasingly urgent. Different types of electromagnetic functional materials are emerging, and the new physical effects and mechanisms triggered by electromagnetic functional materials with different structures are giving them boundless vitality. Carbon-based materials doped with metal single atoms have attracted widespread attention in the field of electromagnetic functional materials due to their lightweight, excellent electrical conductivity and relaxation loss characteristics. However, a universally applicable method for preparing carbon-based materials doped with metal single atoms is currently lacking. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing metal single-atom doped nanoflower-like porous carbon shells that is universal, simple in process, and highly efficient, and shows potential application capabilities in the field of electromagnetic functional materials.

[0004] To address the aforementioned technical problems, the present invention adopts the following technical solution:

[0005] The purpose of this invention is to provide a method for preparing a nano-flower-like porous carbon shell doped with single-atom tungsten, characterized by comprising the following steps:

[0006] Step 1: Add 3-aminopropyltriethoxysilane and flower-like silica to toluene, and then heat to obtain functionalized flower-like silica;

[0007] Step 2: Functionalized flower-shaped silica, chitosan, and sodium tungstate are ultrasonically dispersed in an aqueous solution of glacial acetic acid, stirred at room temperature, and subjected to hydrothermal reaction; then carbonized at high temperature under an inert gas atmosphere.

[0008] Step 3: Then immerse it in hydrofluoric acid to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

[0009] Further specifying, in step 1, 3 mL to 5 mL of 3-aminopropyltriethoxysilane and 1 g to 1.5 g of flower-like silica are added to 300 mL to 350 mL of toluene.

[0010] Further specifying, in step 1, the heat treatment is carried out at 65℃~75℃ for 12h~13h.

[0011] Further specifying, in step 2, 1g of functionalized flower-shaped silica, 2g of chitosan, and 0.1g–0.3g of sodium tungstate are ultrasonically dispersed in 60mL of an aqueous solution of glacial acetic acid; the concentration of the aqueous solution of glacial acetic acid is 2 vol.%–2.5 vol.%.

[0012] Further specifying, in step 2, magnetic stirring is performed at room temperature for 4–5 hours at a stirring speed of 1000 rpm.

[0013] Further specifying, in step 2, the hydrothermal reaction is carried out at 180℃~190℃ for 12h~13h; the inert gas is Ar; the carbonization treatment is carried out at 800℃~850℃ for at least 2h, and the heating rate is 2.5℃ / min~3℃ / min.

[0014] Further specifying, the concentration of the hydrofluoric acid aqueous solution in step 3 is 20 vol% to 40 vol.%; the soaking time is 10 h to 12 h.

[0015] The present invention also provides a nanoflower-like porous carbon shell of doped tungsten nanoparticles prepared by any of the methods described above, with a diameter of 200 nm to 250 nm.

[0016] The present invention also provides a composite material, using a porous carbon shell prepared by any of the methods described above as a filler and paraffin as a matrix; the amount of the porous carbon shell added is 8 wt.% to 10 wt.%.

[0017] The porous carbon shell is added at 8 wt.%, with a minimum reflection loss of -56.4 dB and an effective absorption bandwidth of 6.1 GHz at 2.0 mm, exhibiting excellent electromagnetic energy attenuation characteristics.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention features a simple and universally applicable process. The prepared nanoflower-shaped porous carbon shell loaded with single-atom tungsten has a diameter of approximately 200 nm. When the prepared nanoflower-shaped porous carbon shell loaded with single-atom tungsten is added to a paraffin matrix at an amount of only 8 wt.%, the minimum reflection loss is -56.4 dB, and the effective absorption bandwidth reaches 6.1 GHz at 2.0 mm.

[0020] The preparation method of this invention has the characteristics of universality, requiring few equipment, simple process, and high product preparation efficiency.

[0021] The method of this invention produces a porous carbon shell with a diameter of approximately 200 nm, bearing a tungsten nanoparticle-loaded structure. This tungsten nanoparticle-loaded porous carbon shell exhibits excellent electromagnetic energy loss characteristics. Research on this composite material actively promotes the development of metal heteroatom-doped carbon shell structures in the field of electromagnetic wave absorbing materials, and facilitates the development and application of new materials under carbon shells. The tungsten nanoparticle-loaded porous carbon shell prepared by this invention can be applied to electromagnetic stealth technology, communications, electromagnetic shielding, human health protection, and intelligent electronic communications, actively promoting the progress of electronic information technology in my country.

[0022] To further understand the features and technical content of this invention, please refer to the following detailed description and accompanying drawings. However, the accompanying drawings are for reference and illustration only and are not intended to limit the invention. Attached Figure Description

[0023] Figure 1 Here is a scanning electron microscope image of the nanoflower-like porous carbon shell structure of metallic single-atom tungsten prepared by the method in Example 1;

[0024] Figure 2 The electromagnetic wave attenuation performance of the nanoflower-like porous carbon shell structure of metallic single-atom tungsten prepared by the method of Example 1 when the amount added to the paraffin matrix is ​​only 8 wt.%.

[0025] Figure 3 The electromagnetic wave attenuation performance of the nanoflower-like porous carbon shell structure of tungsten nanoparticles prepared by the method of Example 3 when the amount added to the paraffin matrix is ​​only 8 wt.%. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, while not limiting the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0027] Example 1: The preparation method of the nanoflower-like porous carbon shell doped with single-atom tungsten in this example is carried out according to the following steps:

[0028] Step (1): Add 3 mL of 3-aminopropyltriethoxysilane and 1 g of flower-like silica to 300 mL of toluene, and then heat at 65 °C for 12 h to obtain functionalized flower-like silica.

[0029] Step (2): Take 1g of the functionalized flower-shaped silica obtained in step (1), and then ultrasonically disperse it together with 2g of chitosan and 0.3g of sodium tungstate in 60mL of 2vol.% aqueous solution of glacial acetic acid at an ultrasonic frequency of 20KHz, and stir at 1000rpm for 7h at room temperature.

[0030] Step (3): Transfer the mixed solution obtained in step (2) to a 100 mL Teflon reactor and hydrothermally react at 180 °C for 12 h.

[0031] Step (4): Place the product obtained after hydrothermal treatment (3) into a tube furnace and carbonize it at 800°C for 2 hours in an argon atmosphere (purity of 99.999%).

[0032] Step (5): Soak the product obtained in (4) in a 20 vol% hydrofluoric acid aqueous solution for 12 h to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

[0033] Scanning electron microscope (SEM) images of the nanoflower-like porous carbon shell structure of tungsten nanoparticles prepared by the method in this embodiment are shown below. Figure 1 As shown, by Figure 1 It can be seen that a nanoflower-like porous carbon shell structure loaded with tungsten single atoms has been successfully prepared.

[0034] The electromagnetic wave attenuation performance of the nanoflower-like porous carbon shell structure of tungsten nanoparticles in this embodiment, when added to a paraffin matrix at an amount of only 8 wt.%, is shown in the figure below. Figure 2 As shown, by Figure 2 It is known that the porous carbon shell is added at 8 wt.%, the composite material has a minimum reflection loss of -56.4 dB, and the effective absorption bandwidth can reach 6.1 GHz at 2.0 mm.

[0035] Example 2: The preparation method of the nanoflower-like porous carbon shell doped with single-atom tungsten in this example is carried out according to the following steps:

[0036] Step (1): Add 5 mL of 3-aminopropyltriethoxysilane and 1 g of flower-like silica to 300 mL of toluene, and then heat at 75 °C for 12 h to obtain functionalized flower-like silica.

[0037] Step (2): Take 1g of the functionalized flower-shaped silica obtained in step (1), and then ultrasonically disperse it together with 2g of chitosan and 0.3g of sodium tungstate in 60mL of 2vol.% aqueous solution of glacial acetic acid at an ultrasonic frequency of 20KHz, and stir at 1000rpm for 7h at room temperature.

[0038] Step (3): Transfer the mixed solution obtained in step (2) to a 100 mL Teflon reactor and hydrothermally react at 180 °C for 12 h.

[0039] Step (4): Place the product obtained after hydrothermal treatment (3) into a tube furnace and carbonize it at 800°C for 2 hours in an argon atmosphere (purity of 99.999%).

[0040] Step (5): Soak the product obtained in (4) in a 20 vol% hydrofluoric acid aqueous solution for 12 h to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

[0041] Example 3: The preparation method of the nanoflower-like porous carbon shell doped with single-atom tungsten in this example is carried out according to the following steps:

[0042] Step (1): Add 3 mL of 3-aminopropyltriethoxysilane and 1 g of flower-like silica to 300 mL of toluene, and then heat at 65 °C for 12 h at room temperature to obtain functionalized flower-like silica.

[0043] Step (2): Take 1g of the functionalized flower-shaped silica obtained in step (1), and then ultrasonically disperse it together with 2g of chitosan and 0.3g of sodium tungstate in 60mL of 2vol.% aqueous solution of glacial acetic acid at an ultrasonic frequency of 20KHz, and stir at 1000rpm for 7h at room temperature.

[0044] Step (3): Transfer the mixed solution obtained in step (2) to a 100 mL Teflon reactor and hydrothermally react at 180 °C for 12 h.

[0045] Step (4): Place the product obtained after hydrothermal treatment (3) into a tube furnace and carbonize it at 800°C for 2 hours in an argon atmosphere (purity of 99.999%).

[0046] Step (5): Soak the product obtained in (4) in a 20 vol% hydrofluoric acid aqueous solution for 12 h to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

[0047] Using a porous carbon shell prepared by the method described in this embodiment as a filler and paraffin as a matrix; when the amount of porous carbon shell added to the paraffin matrix is ​​8 wt.%, the electromagnetic wave attenuation performance of the composite material is as follows: Figure 3 As shown. Figure 3 It is known that the porous carbon shell is added at 8 wt.%, the composite material has a minimum reflection loss of -50.4 dB, and the effective absorption bandwidth can reach 3.6 GHz at 2.0 mm.

[0048] Example 4: The preparation method of the nanoflower-like porous carbon shell doped with single-atom tungsten in this example is carried out according to the following steps:

[0049] Step (1): Add 3 mL of 3-aminopropyltriethoxysilane and 1 g of flower-like silica to 300 mL of toluene, and then heat at 65 °C for 12 h to obtain functionalized flower-like silica.

[0050] Step (2): Take 1g of the functionalized flower-shaped silica obtained in step (1), and then ultrasonically disperse it together with 2g of chitosan and 0.3g of sodium tungstate in 60mL of 2vol.% aqueous solution of glacial acetic acid at an ultrasonic frequency of 20KHz, and stir at 1000rpm for 7h at room temperature.

[0051] Step (3): Transfer the mixed solution obtained in step (2) to a 100 mL Teflon reactor and hydrothermally react at 200 °C for 12 h.

[0052] Step (4): Place the product obtained after hydrothermal treatment (3) into a tube furnace and carbonize it at 800°C for 2 hours in an argon atmosphere (purity of 99.999%).

[0053] Step (5): Soak the product obtained in (4) in a 20 vol% hydrofluoric acid aqueous solution for 12 h to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

[0054] Example 5: The preparation method of the nanoflower-like porous carbon shell doped with single-atom tungsten in this example is carried out according to the following steps:

[0055] Step (1): Add 3 mL of 3-aminopropyltriethoxysilane and 1 g of flower-like silica to 300 mL of toluene, and then heat at 65 °C for 12 h to obtain functionalized flower-like silica.

[0056] Step (2): Take 1g of the functionalized flower-shaped silica obtained in step (1), and then ultrasonically disperse it together with 2g of chitosan and 0.3g of sodium tungstate in 60mL of 2vol.% aqueous solution of glacial acetic acid at an ultrasonic frequency of 20KHz, and stir at 1000rpm for 7h at room temperature.

[0057] Step (3): Transfer the mixed solution obtained in step (2) to a 100 mL Teflon reactor and perform a hydrothermal reaction at 180 °C for 12 h.

[0058] Step (4): Place the product obtained after hydrothermal treatment (3) into a tube furnace and carbonize it at 800°C for 2 hours in an argon atmosphere (purity 99.999%).

[0059] Step (5): Soak the product obtained in (4) in a 40 vol% hydrofluoric acid aqueous solution for 12 h to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

[0060] The specific embodiments of the present invention have been described above. It should be noted that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a nanoflower-like porous carbon shell doped with single-atom tungsten metal, characterized in that, Includes the following steps: Step 1: Add 3-aminopropyltriethoxysilane and flower-like silica to toluene, and then heat to obtain functionalized flower-like silica; Step 2: Functionalized flower-shaped silica, chitosan, and sodium tungstate are ultrasonically dispersed in an aqueous solution of glacial acetic acid, stirred at room temperature, and subjected to hydrothermal reaction; then carbonized at high temperature under an inert gas atmosphere. Step 3: Then immerse it in hydrofluoric acid aqueous solution to obtain a nano-flower-like porous carbon shell doped with tungsten nanoparticles.

2. The method according to claim 1, characterized in that, In step 1, 3 mL to 5 mL of 3-aminopropyltriethoxysilane and 1 g to 1.5 g of flower-like silica are added to 300 mL to 350 mL of toluene.

3. The method according to claim 1, characterized in that, In step 1, the temperature is increased to 65℃~75℃ for 12 h~13 h.

4. The method according to claim 2, characterized in that, In step 2, 1g of functionalized flower-shaped silica, 2g of chitosan and 0.1g~0.3g of sodium tungstate are ultrasonically dispersed in 60ml of glacial acetic acid aqueous solution; the concentration of the glacial acetic acid aqueous solution is 2 vol.%~2.5 vol.%.

5. The method according to claim 1, characterized in that, In step 2, the mixture is magnetically stirred at room temperature for 4-5 hours at a stirring speed of 1000 rpm.

6. The method according to claim 1, characterized in that, In step 2, the hydrothermal reaction is carried out at 180 ℃~190 ℃ for 12 h~13 h; the inert gas is Ar; the carbonization treatment is carried out at 800 ℃~850 ℃ for at least 2 h, with a heating rate of 2.5 ℃ / min~3 ℃ / min.

7. The method according to claim 1, characterized in that, In step 3, the concentration of the hydrofluoric acid aqueous solution is 20 vol% ~ 40 vol.%; the soaking time is 10 h ~ 12 h.

8. A nanoflower-like porous carbon shell of doped tungsten nanoparticles prepared by the method of any one of claims 1-7, having a diameter of 200-250 nm.

9. A composite material, characterized in that... The porous carbon shell prepared by any one of claims 1-7 is used as a filler, and paraffin is used as a matrix; the amount of the porous carbon shell added is 8 wt.%~10 wt.%.

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