Strong contribution of in situ grown nanowires to enhance the thermostabilities and microwave absorption properties of porous graphene foams under different atmospheres
Strong contribution of in situ grown nanowires to enhance the thermostabilities and microwave absorption properties of porous graphene foams under different atmospheres
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原位生长的纳米线对提高多孔石墨烯泡沫在不同气氛下的热稳定性和微波吸收性能有很大贡献
DOI：
10.1039/c7tc04102k
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发表时间：
2017-12-07
影响因子：
6.4
通讯作者：
Luo, Xiaoguang
中科院分区：
文献类型：
--
作者：
Dong, Shun;Song, Juntao;Luo, Xiaoguang
采用原位生长的 Si3N4 纳米线 (Si3N4nws) 和 SiC 纳米线 (SiCnws) 装饰的三维 (3D) 分层石墨烯泡沫 (GF) 的独立式高性能电磁 (EM) 吸波材料分别在流动 N-2 和 Ar 下采用一步碳热还原工艺制备。所获得的 Si3N4nws 由直径约为 200 nm 的单晶 Si3N4 核和厚度约为 2 nm 的非晶 SiOx 层组成，而 SiCnws 由直径约为 200 nm 的单晶 SiC 核和平均厚度为 25 nm 的非晶 SiOx 壳组成。通过将Si3N4nws和SiCnws掺入GFs中，复合材料的热稳定性和电磁吸收性能同时得到有效提高。 Si3N(4nws)、-GF 和 SiCnws-GF 在超过 640 摄氏度的空气中具有热稳定性，重量保持率分别高于 98% 和 94%。与纯GF相比，S3N(4nws)-GF表现出更强的电磁微波吸收性能，在6.4 GHz、厚度为2.36 mm时，最小反射损耗(RL)值为-48.7 dB，而SiCnws-GF在5.9 GHz、厚度为2.6 mm时，最小反射损耗(RL)值可低至-67.8 dB。本研究中的多尺度 Si3N4nws-GFs 和 SiCnws-GFs 作为在关键环境中具有强电磁波吸收性能的吸收材料是非常有前途的。
Free-standing and high-performance electromagnetic (EM) absorbing materials of three-dimensional (3D) hierarchical graphene foams (GFs) decorated with in situ grown Si3N4 nanowires (Si3N4nws) and SiC nanowires (SiCnws) were prepared using a one-step carbothermal reduction process under flowing N-2 and Ar, respectively. The as-obtained Si3N4nws consist of single crystalline Si3N4 cores similar to 200 nm in diameter and amorphous SiOx Layers similar to 2 nm in thickness, and the SiCnws are composed of single crystalline SiC cores about 200 nm in diameter and amorphous SiOx, sheaths with an average thickness of 25 nm. By incorporating Si3N4nws and SiCnws into GFs, the thermostabiLity and EM absorption of the composites were simultaneously improved effectively. The Si3N(4nws),-GFs and SiCnws-GFs were thermostabLe in an air atmosphere beyond similar to 640 degrees C with above 98% and 94% weight retention, respectively. Compared with those of pure GFs, the S3N(4nws)-GFs exhibit a stronger EM microwave absorption performance with a minimum reflection Loss (RL) value of -48.7 dB at 6.4 GHz with a thickness of 2.36 mm, and the minimum RL vaLue of the SiCnws-GFs could be as Low as -67.8 dB at 5.9 GHz with 2.6 mm thickness. The multiscale Si3N4nws-GFs and SiCnws-GFs in the present study are very promising as absorber materials with strong EM wave absorption performance in critical environments.