Three-dimensional (3D) graphene aerogel-supported SnO₂ (SGA) nanoparticles (NPs) are presented by a one-pot solvothermal treatment of graphene oxide in the presence of SnCl₄ followed by freeze drying. The size of SnO₂ nanoparticles on the graphene aerogel is as small as 5–10 nm with uniform distribution. The 3D SnO₂–graphene aerogel exhibits interconnected macroporous networks which will be beneficial for gas detection. The SGA shows excellent response and selectivity towards NO₂ when other common gases are present at room temperature (RT). The gas sensing responses of the resulting nanocomposites demonstrate that macroporosity in the SGA significantly improves the response and recovery time compared with the 2D SnO₂–graphene nanocomposite. The sensing mechanism and the reasons for the better response are also discussed.

Three-dimensional graphene aerogel-supported Fe ₃ O ₄ nanoparticles for efficient detection of NO ₂ at room temperature are reported.