具有超疏水宽频吸波性能的磁功能化石墨烯气凝胶

Magnetic Functionalized Graphene Aerogel with Super-hydrophobic and Ultrawide Bandwidth Absorption Properties

三维“泡沫型”结构石墨烯气凝胶具有高比表面积及独特的多孔结构特性,使其成为了最具发展潜力的轻质宽频微波吸收材料。采用化学还原自组装法构筑含有金属乙酰丙酮络合物的石墨烯水凝胶,经冷冻干燥、原位热解过程成功制备Co磁性纳米粒子修饰的超疏水石墨烯气凝胶(Co@SMGA),通过粉末X射线衍射(XRD)、拉曼光谱、X射线光电子能谱(XPS)、扫描电镜(SEM)和透射电镜(TEM)等手段测试表征复合材料的结构和物相组成,基于同轴法测试其电磁参数并利用Matlab模拟反射损耗。实验结果表明:煅烧温度对磁功能化石墨烯气凝胶复合材料的微波吸收性能有重要影响,煅烧温度450℃、超低填充量4 wt%的复合材料具有最优异的吸波性能,其最小反射损耗(RLmin)为-45.3 dB,匹配厚度为2.5 mm时,有效吸收带宽(EAB)达到6.5 GHz。

Graphene aerogels due to their unique three-dimensional foam porous structure and high surface area have been a candidate for lightweight,broadband microwave absorption materials.In this paper,a graphene hydrogel containing metal acetylacetone complex was constructed by chemical reduction self-assembly method.Superhydrophobic graphene aerogels modified with magnetic Co nanoparticles were successfully prepared by freeze-drying and in situ pyrolysis process(Co@SMGA).The structure and phase composition of the composites were tested and characterized by powder X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM) and transmission electron microscopy(TEM),respectively.The electromagnetic parameters were measured by coaxial method and the reflection loss was simulated by Matlab.The results show that the calcination temperatures have an important effect on the microwave absorption properties of magnetic functionalized graphene aerogels composites.The results demonstrated that when the calcination temperature was 450 ℃,the Co@SMGA-450hybrids with only 4wt% of functional fillers reached a minimum reflection loss value of-45.3 dB and a maximum effective absorption bandwidth(EAB,below-10 dB) of 6.5 GHz at 2.5 mm.