Preparation method and application of sulfur atom doped phoenix tree floc biomass derived carbon material

Abstract

The invention belongs to the technical field of electromagnetic wave absorbing materials, and particularly relates to a preparation method and application of a sulfur atom doped phoenix tree floc biomass derived carbon material. The preparation method comprises the following steps: carrying out carbonization pyrolysis treatment on a phoenix tree floc biomass carbon material and a sulfur-containing material to obtain the sulfur atom doped phoenix tree floc biomass derived carbon material. According to the invention, a novel effective synthesis strategy is provided for the biomass-derived carbon-based wave-absorbing material through a method of combining sulfuration reagent content regulation and sulfur atom doping. The material disclosed by the invention has excellent wave-absorbing performance, has the potential of serving as an efficient wave-absorbing agent, and has a relatively good application prospect in the field of civil anti-radiation building materials (coatings, walls and the like). And meanwhile, the preparation process is simple and can be popularized to recycling of natural plant wastes, so that the composite material has a wide application prospect in the field of electromagnetism.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave absorption materials, and particularly relates to a preparation method and application of a sulfur atom-doped phoenix tree catkin biomass-derived carbon material. Background Art

[0002] With the wide application of GHz-frequency electromagnetic waves in fields such as satellites, radars, mobile communications, and high-precision detection, while the invisible electromagnetic waves bring convenience to people, they also cause serious radiation pollution, invading human health and life. Microwave absorption materials can effectively absorb electromagnetic waves and convert them into thermal energy or other forms of energy, thereby greatly weakening or even eliminating the electromagnetic energy of the incident electromagnetic waves, showing good dissipation effects. At the same time, with the continuous expansion of modern application requirements and scenarios, wave-absorbing materials are given higher comprehensive requirements, that is, the thickness of the wave-absorbing body is thin, the mass is light, the absorption frequency band is wide, and the wave-absorbing performance is strong. Therefore, it is urgent to develop new wave-absorbing materials that meet the requirements of "thin, light, wide, and strong".

[0003] Due to the high conductivity and light weight characteristics, carbon materials are considered good dielectric loss type wave-absorbing materials. However, the processes for preparing wave-absorbing materials using carbon fibers, carbon nanotubes, graphene, etc. are complex and costly, thus limiting their large-scale application.

[0004] In recent years, biomass-derived carbon materials have received extensive attention due to their environmental protection, high efficiency, economy and other advantages. However, pure biomass carbon is limited by its intrinsic biomass characteristics and cannot meet the current comprehensive requirements of microwave absorption materials for being "thin, light, wide, and strong", so it cannot be directly used to prepare electromagnetic absorption materials. Ding Chunyan et al. selected Zn(NO3)2 and Chinese parasol tree fruits as the main reactants, and prepared ZnO / PCMT composites through dip coating and thermal etching processes. Effective electromagnetic wave absorption can be achieved under the condition that the mass fraction of Zn(NO3)2 is 6.7% (the effective bandwidth is 5.0 GHz and the minimum reflection loss is -28.9 dB). Kong Xiangkai used waste Chinese parasol tree catkins biomass as the carrier and coal mine waste resource kaolin as the load, and synthesized a dual-waste-derived material of biomass carbon nanotube / kaolin composite by combining surface modification to enhance the interfacial interaction and high-temperature pyrolysis. The microwave absorption performance is as follows: when the thickness is 3.0 mm, the minimum reflection loss (RLmin) reaches -51.5 dB; when the thickness is 2.0 mm, the effective absorption bandwidth (EAB) can reach 6.3 GHz (11.7 - 18.0 GHz). At present, biomass-derived porous carbon-based microwave absorption materials have made great progress in experiments and theories, and can be widely applied due to their environmental protection and sustainable development characteristics, but there are still some difficulties and challenges: (1) The conductive network contributes greatly to the microwave absorption performance of biomass-derived porous carbon-based materials, but there are still problems such as large preparation difficulty and poor stability. (2) The influence of pore structure and pore size distribution on interfacial polarization and electromagnetic properties still needs further study. An alternative strategy is to chemically dope the carbon precursor with heteroatoms directly before carbonization. The present invention first proposes the preparation of sulfur atom-doped Chinese parasol tree catkins biomass-derived carbon materials, which improves the problems existing in current biomass carbon as a microwave absorption material. Summary of the Invention

[0005] To solve the above technical problems, the purpose of the present invention is to provide a preparation method and application of sulfur atom-doped Chinese parasol tree catkins biomass-derived carbon. By combining the regulation of the dosage of sulfur-containing materials and sulfur atom doping, an innovative technical path is provided for the preparation of materials with excellent electromagnetic wave attenuation performance.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A preparation method of sulfur atom-doped Chinese parasol tree catkins biomass-derived carbon materials includes the following steps:

[0008] 1) Wash and dry the Chinese parasol tree catkins, and perform carbonization pyrolysis treatment in an oxygen-free atmosphere to obtain Chinese parasol tree catkins biomass carbon materials;

[0009] 2) Mix the Chinese parasol tree catkins biomass carbon materials with sulfur-containing materials evenly to obtain a carbonization precursor;

[0010] 3) Carbonize and pyrolyze the carbonization precursor in an anaerobic atmosphere to obtain a sulfur atom-doped Firmiana simplex floss biomass-derived carbon material.

[0011] Further, in the above preparation method, in step 1), the reagent for washing is one or both of water and ethanol.

[0012] Further, in the above preparation method, in step 1), the drying temperature is 50-160 °C, and the drying time is 3-32 h.

[0013] Further, in the above preparation method, in step 1), the temperature of the carbonization pyrolysis is 300-500 °C, and the time of the carbonization pyrolysis is 60-180 min.

[0014] Further, in the above preparation method, in step 2), the sulfur-containing material is one or two or more of sulfur, sulfite, and organic sulfur compounds.

[0015] Preferably, the sulfur-containing material is one or two or more of sublimed sulfur, sodium sulfite, thioacetamide, and thiourea.

[0016] Further, in the above preparation method, in step 2), the mass ratio of the sulfur-containing material to the Firmiana simplex floss biomass carbon material is (0.5-2):1.

[0017] Further, in the above preparation method, in step 3), the temperature of the carbonization pyrolysis is 800-900 °C, and the time of the carbonization pyrolysis is 60-180 min.

[0018] Further, in the above preparation method, in steps 1) and 3), the heating rate of the carbonization pyrolysis process is controlled to be 2-5 °C / min.

[0019] Application of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared by the preparation method described in any one of the above in the field of electromagnetic wave absorption as an electromagnetic wave absorption material.

[0020] The beneficial effects of the present invention are:

[0021] The sulfur atom-doped sycamore floss biomass-derived carbon material of the present invention has a large specific surface area and a small density, realizing the characteristics of "thin, light, wide, and strong" possessed by electromagnetic wave absorption materials. The present invention provides a new effective synthesis strategy for biomass-derived carbon-based microwave absorption materials by combining the regulation of the content of sulfurizing reagents and sulfur atom doping. Compared with most reported carbon materials, the composite material of sulfur atom-doped biomass carbon has comparable or even better microwave absorption performance. It reaches the minimum reflection loss of -58.28 dB at 16.32 GHz only when the thickness is 2.05 mm. At a matching thickness of 2.35 mm, the effective absorption bandwidth reaches 6.96 GHz (11.04 - 18.0 GHz), covering the entire Ku band. The application of this band in satellite communication, meteorological radar, and military detection systems can reduce the reflection and interference of signals, improving the signal quality and stability of communication systems. The improvement of the microwave absorption performance of the present invention benefits from the following aspects:

[0022] (1) Regulation of conductivity: The unique porous structure and carbon network of biomass-derived porous carbon-based microwave absorption materials form conductive channels at the microscale. The present invention uses porous carbon materials as good sulfur carriers, not only regulating the conductivity of carbon materials to avoid the influence of skin effect on the impedance matching of materials, but also effectively compensating for the disadvantage of poor conductivity of intermediate electrochemical reaction products.

[0023] (2) Dipole polarization: Functional groups such as C-S and C-SOx-C can be equivalent to electric dipoles, providing dipole polarization to increase dielectric relaxation.

[0024] (3) Interfacial polarization: The doping of heteroatoms forms a large number of hetero-interfaces with sycamore floss after high-temperature carbonization. Due to the difference in their conductivities and the irradiation of electromagnetic waves, it is easy to form an interfacial polarization effect, thereby greatly attenuating electromagnetic waves.

[0025] (4) Multiple reflections and scattering: The material has a hollow structure, which can undergo multiple reflections and scattering, not only increasing the interaction path between electromagnetic waves and the microwave absorption material, but also expanding the effective absorption cross-section of the microwave absorption material, improving the electromagnetic wave absorption performance of the material.

[0026] (5) Regulation of pore size: Through high-temperature pyrolysis, macroporous channels at the micron scale are formed, and at the same time, the pore structure is more uniform, enabling the material to have rich polarization and relaxation, and improving the microwave absorption performance of the material.

[0027] The excellent electromagnetic wave absorption performance of the materials of the present invention benefits from the excellent conductivity of the carbon materials, the suitable structure and size of the materials, and the synergistic effect of the interfaces and dipoles generated by the appropriate doping of S atoms, achieving good impedance matching and a high attenuation constant. This low-cost electromagnetic wave absorption material inspires the preparation of dielectric composite materials with appropriate conductivity, more heterogeneous interfaces, and more pores through the doping of single atoms and simple heat treatment. It has the potential to be an efficient electromagnetic wave absorber and has good application prospects in the field of civil radiation protection building materials (coatings, walls, etc.). At the same time, its preparation process is simple and can be extended to the recycling of natural plant waste, making it have broad application prospects in the electromagnetic field. Description of the Drawings

[0028] Figure 1 It is the SEM image (10μm) of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1.

[0029] Figure 2 It is the SEM image (20μm) of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1.

[0030] Figure 3 It is the S2p orbital XPS spectrum of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1.

[0031] Figure 4 It is the C1s orbital XPS spectrum of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1.

[0032] Figure 5 It is the 3D reflection loss diagram of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1.

[0033] Figure 6 It is the 2D reflection loss diagram of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1.

[0034] Figure 7 It is the XRD pattern of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1. Detailed Embodiments

[0035] Example 1

[0036] 1) Take 2 - 3 g of Firmiana simplex floss and wash it three times with deionized water and anhydrous ethanol successively, and dry it in an oven at 80°C for 12 h. Transfer the dried Firmiana simplex floss to a tubular furnace, and under the protection of argon, heat it to 400°C at a heating rate of 5°C / min and calcine for 2 h. After cooling, take out the Firmiana simplex floss biomass carbon material sample.

[0037] 2) Mix 0.5 g of Firmiana simplex floss biomass carbon material with 0.5 g of sublimed sulfur in an agate mortar, transfer the mixture to a porcelain boat, and place it in a tube furnace for calcination. Under an argon atmosphere, heat it to 800 °C at a heating rate of 5 °C / min and hold for 2 h to obtain the final product, i.e., sulfur atom-doped Firmiana simplex floss biomass-derived carbon material.

[0038] 3) Heat and thoroughly mix the prepared sulfur atom-doped Firmiana simplex floss biomass-derived carbon material sample with sliced paraffin in a mass ratio of 2:8 to obtain a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. Measure the electromagnetic parameters at a frequency of 2 - 18 GHz using a vector network analyzer. Calculate the measured complex permittivity and complex permeability to obtain a minimum reflection loss RLmin of -58.28 dB at a thickness of 2.05 mm, and the maximum effective frequency bandwidth is 6.96 GHz.

[0039] Figure 1-2 Figure 7 is the SEM image of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1. It can be seen that the diameter of the Firmiana simplex floss-derived carbon tube is about 20 μm.

[0040] Figure 3-4 Figure 11 is the XPS spectra of the S2p and C1s orbitals of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material, effectively proving that sulfur atoms are successfully doped into the interior of the material.

[0041] Figure 5-6 Figure 15 is the 3D and 2D reflection loss diagrams of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1. As can be seen from the figure, when the thickness is 2.05 mm, the strongest reflection absorption of -58.28 dB appears at 16.32 GHz. It can be seen that the wave absorption performance is enhanced by sulfur doping, the frequency band width becomes larger, and the absorption peak shifts to lower frequencies as the thickness increases.

[0042] Figure 7 Figure 19 is the XRD pattern of the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in Example 1. The diffraction peaks of graphitized carbon (120) and (002) are located at 21.2° and 25.7°, respectively. Therefore, graphite carbon fibers are formed.

[0043] In summary, the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material prepared in this example has high electromagnetic wave absorption performance. Therefore, the sulfur atom-doped Firmiana simplex floss biomass-derived carbon material of the present invention has an ideal development prospect in the field of electromagnetic wave absorption.

[0044] Example 2

[0045] 1) Take 2 - 3 g of Firmiana simplex floss, wash it three times successively with deionized water and absolute ethanol, and dry it in an oven at 80 °C for 12 h. Transfer the dried Firmiana simplex floss to a tubular furnace, and under argon protection, heat it to 400 °C at a heating rate of 5 °C / min and calcine for 2 h. After cooling, take out the Firmiana simplex floss biomass carbon material sample.

[0046] 2) Thoroughly mix 0.5 g of the Firmiana simplex floss biomass carbon material with 0.25 g of sublimed sulfur in an agate mortar and transfer it to a porcelain boat. Place it in a tubular furnace for calcination. Under an argon atmosphere, heat it to 800 °C at a heating rate of 5 °C / min and hold for 2 h to obtain the final product, namely the sulfur atom - doped Firmiana simplex floss biomass - derived carbon material.

[0047] 3) Heat and thoroughly mix the prepared sulfur atom - doped Firmiana simplex floss biomass - derived carbon material sample with paraffin wax in a mass ratio of 2:8 to obtain a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. Measure the electromagnetic parameters at a frequency of 2 - 18 GHz using a vector network analyzer. Calculate the measured complex permittivity and complex permeability to obtain a minimum reflection loss RLmin of - 75.55 dB at a thickness of 1.71 mm, and the maximum effective frequency bandwidth is 4.8 GHz.

[0048] Comparative Example 1

[0049] 1) Take 2 - 3 g of Firmiana simplex floss, wash it three times successively with deionized water and absolute ethanol, and dry it in an oven at 80 °C for 12 h. Transfer the dried Firmiana simplex floss to a tubular furnace, and under argon protection, heat it to 400 °C at a heating rate of 5 °C / min and calcine for 2 h. After cooling, take out the Firmiana simplex floss biomass carbon material sample.

[0050] 2) Thoroughly mix 0.5 g of the Firmiana simplex floss biomass carbon material with 0.5 g of sublimed sulfur in an agate mortar and transfer it to a porcelain boat. Place it in a tubular furnace for calcination. Under an argon atmosphere, heat it to 1000 °C at a heating rate of 5 °C / min and hold for 2 h to obtain the final product, namely the sulfur atom - doped Firmiana simplex floss biomass - derived carbon material.

[0051] Measure the electromagnetic parameters of the material prepared in Comparative Example 1 in the same manner as described in Example 1. Calculate the measured complex permittivity and complex permeability to obtain a minimum reflection loss RLmin of - 9.23 dB at a thickness of 0.93 mm, and there is no effective frequency bandwidth. It shows that CMT - 800 - S1 has an absolute advantage over CMT - 1000 - S1.

[0052] Comparative Example 2

[0053] 1) Take 2 - 3 g of phoenix tree catkins and wash them successively 3 times with deionized water and absolute ethanol, then dry them in an oven at 80 °C for 12 h. Transfer the dried phoenix tree catkins to a tubular furnace, and under argon protection, heat them to 400 °C at a heating rate of 5 °C / min and calcine for 2 h. After cooling, take out the phoenix tree catkins biomass carbon material sample.

[0054] 2) Place 0.5 g of the phoenix tree catkins biomass carbon material in a tubular furnace for calcination. Under an argon atmosphere, heat it to 900 °C at a heating rate of 5 °C / min and hold for 2 h to obtain the final product, namely the phoenix tree catkins biomass - derived carbon material.

[0055] Measure the electromagnetic parameters of the material prepared in Comparative Example 2 in the same manner as described in Example 1. Calculate the complex permittivity and complex permeability measured, and obtain that the minimum reflection loss RLmin is - 8.98 dB at a thickness of 0.69 mm, and there is no effective frequency bandwidth. This once again proves the important significance of sulfur atom doping in improving the microwave absorption performance of the material.

[0056] The above has elaborated in detail on the embodiments provided by the present invention. Specific embodiments of the present invention are used to expound the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a sulfur atom-doped biomass-derived carbon material from plane tree catkins, characterized in that, The steps include: 1) washing and drying the Chinese tung oil fluff, and subjecting the carbonized and pyrolyzed Chinese tung oil fluff to a carbonization and pyrolysis treatment in an oxygen-free atmosphere to obtain a Chinese tung oil fluff biomass carbon material; 2) mixing the sycamore fluff biomass carbon material and the sulfur-containing material uniformly to obtain a carbonized precursor; 3) The carbonized precursor is subjected to carbonization pyrolysis treatment in an oxygen-free atmosphere to obtain a sulfur atom-doped tung oil tree fluff biomass-derived carbon material.

2. The preparation method according to claim 1, characterized in that In step 1), the washing reagent is one or both of water and ethanol.

3. The preparation method according to claim 1, wherein, In step 1), the drying temperature is 50-160° C., and the drying time is 3-32 hours.

4. The preparation method according to claim 1, characterized in that, In step 1), the temperature of the carbonization pyrolysis is 300-500° C., and the time of the carbonization pyrolysis is 60-180 min.

5. The preparation method according to claim 1, characterized in that, In step 2), the sulfur-containing material is one or two or more of elemental sulfur, sulfite and organic sulfur compound.

6. The preparation method according to claim 5, characterized in that, In step 2), the sulfur-containing material is one or two or more of sublimated sulfur, sodium sulfite, thioacetamide and thiourea.

7. The preparation method according to claim 1, wherein, In step 2), the mass ratio of the sulfur-containing material to the Chinese parasol tree fluff biomass carbon material is (0.5-2):

1.

8. The preparation method according to claim 1, characterized in that, In step 3), the temperature of the carbonization pyrolysis is 800-900° C., and the time of the carbonization pyrolysis is 60-180 min.

9. The preparation method according to claim 4 or 8, characterized in that The heating rate of the carbonization pyrolysis process is controlled to be 2-5°C / min.

10. Use of the sulfur-doped Chinese parasol tree fluff biomass-derived carbon material prepared by the preparation method according to any one of claims 1 to 9 as an electromagnetic wave absorbing material in the field of electromagnetic wave absorption.

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