Synthesis and Characterization of Highly Crystalline Graphene Aerogels
journal contributionposted on 28.10.2014, 00:00 by Marcus A. Worsley, Thang T. Pham, Aiming Yan, Swanee J. Shin, Jonathan R. I. Lee, Michael Bagge-Hansen, William Mickelson, Alex Zettl
Aerogels are used in a broad range of scientific and industrial applications due to their large surface areas, ultrafine pore sizes, and extremely low densities. Recently, a large number of reports have described graphene aerogels based on the reduction of graphene oxide (GO). Though these GO-based aerogels represent a considerable advance relative to traditional carbon aerogels, they remain significantly inferior to individual graphene sheets due to their poor crystallinity. Here, we report a straightforward method to synthesize highly crystalline GO-based graphene aerogels via high-temperature processing common in commercial graphite production. The crystallization of the graphene aerogels versus annealing temperature is characterized using Raman and X-ray absorption spectroscopy, X-ray diffraction, and electron microscopy. Nitrogen porosimetry shows that the highly crystalline graphene macrostructure maintains a high surface area and ultrafine pore size. Because of their enhanced crystallinity, these graphene aerogels exhibit a ∼200 °C improvement in oxidation temperature and an order of magnitude increase in electrical conductivity.