Suzhou Institute of Nano-Tech and Nano-Bionics , Chinese Academy of Sciences , Suzhou 215123 , P. R. China.
University of Chinese Academy of Sciences , Beijing 10000 , P. R. China.
Langmuir. 2018 Jul 31;34(30):9004-9014. doi: 10.1021/acs.langmuir.8b01410. Epub 2018 Jul 17.
Bulk graphene aerogels with high electrical conductivity, ultralow density, and high specific surface area have attracted significant attention because of their fascinating performances in energy storage, catalysis, absorption, sensor, electromagnetic shielding, etc. However, graphene aerogel microgranules (i.e., reducing the size of the bulk aerogels into microscale) and their performances in the electromagnetic field have been ignored. Herein, we report a new strategy to make floatable graphene aerogel microgranules with high hydrophobicity (137°), low density (13.5 mg/cm), and high specific surface area (516 m/g). These microgranules were synthesized initially from reduced graphene oxide (rGO) hydrogel microparticles and then in situ-modified by silica nanoparticles. Further investigations have demonstrated that the resulting silica-modified rGO aerogel microgranules possess highly efficient static electromagnetic screening (average 30.3 dB in 8-18 GHz) and dynamic infrared shielding (higher than 10 dB during floatation in air for 15 min) properties. The work reported here should give much inspiration to make more functional aerogel microgranules used in various emerging fields.
具有高电导率、超低密度和高比表面积的块状石墨烯气凝胶因其在储能、催化、吸收、传感器、电磁屏蔽等方面的迷人性能而引起了广泛关注。然而，石墨烯气凝胶微颗粒（即将块状气凝胶的尺寸减小到微尺度）及其在电磁场中的性能尚未得到关注。在此，我们报告了一种新策略，可制造出具有高疏水性（137°）、低密度（13.5mg/cm）和高比表面积（516m/g）的可浮石墨烯气凝胶微颗粒。这些微颗粒最初是由还原氧化石墨烯（rGO）水凝胶微颗粒合成的，然后通过硅纳米颗粒进行原位修饰。进一步的研究表明，所得到的二氧化硅修饰的 rGO 气凝胶微颗粒具有高效的静态电磁屏蔽（在 8-18GHz 范围内平均为 30.3dB）和动态红外屏蔽（在空气中漂浮 15 分钟时高于 10dB）性能。这里报道的工作应该为制造更多用于各种新兴领域的功能性气凝胶微颗粒提供很多启示。
