Self-assembly synthesis of 3D graphene/nano-Fe3O4 hybrid aerogels with improved mechanical and thermal properties

Graphene aerogel and graphene-magnetite hybrid aerogel were prepared using hydrothermal method followed by a freeze-drying process. Magnetite nanoparticles were encapsulated by graphene sheets in an electrostatic self-assembly process. The morphology and properties of aerogels were characterized by several techniques including UV-Vis spectroscopy, Raman spectroscopy, FESEM, TEM and XRD. The mechanical and thermal behavior of the aerogels were evaluated at different concentration levels of Fe3O4 nanoparticles (0, 10, 20 and 30 wt%). The compressive strengths of the hybrid aerogels at the strain of 80% for graphene aerogels containing 0, 10, 20 and 30 wt% Fe3O4 nanoparticles were determined to be 5.93, 12.96, 6.85, and 6.15 kPa, respectively. The highest mechanical properties were achieved for the sample containing 10 wt% Fe3O4 nanoparticles (FGA10). Thermal analysis revealed that FGA10 sample had a 15% less weight loss when heated up to 600 °C compared with that for the bare graphene aerogel, indicating the formation of a more thermally stable structure. Furthermore, adding Fe3O4 nanoparticles improved the thermal insulation performance of the graphene aerogel, since the dynamic heat transfer rate and heat dissipation rate of FGA10 were lower than those for the bare graphene aerogel.