▎ 摘　　要

Three-dimensional graphene aerogel-supported Fe3O4 nanoparticles for efficient detection of NO2 at room temperature are reported. The graphene composite exhibits an interconnected macroporous framework of graphene sheets with uniform dispersion of Fe3O4 nanoparticles. Such a hybrid nanostructure would effectively facilitate target gas diffusion and exhibit significantly higher response and faster recovery speed than pure reduced graphene oxide, highlighting the importance of the 3D macropores and high specific surface area of the graphene aerogel support for improving sensing performance. We also propose a hybrid sensing mechanism for the drastic improvement in the sensing behavior which combines the resistance modulation of Fe3O4 nanoparticles/graphene heterointerfaces in addition to the radial modulation of the surface depletion layer of the Fe3O4 nanocomposite.