Novel microrecycled ZnO nanoparticles decorated macroporous 3D graphene hybrid aerogel for efficient detection of NO2 at room temperature

Abstract A novel macroporous microrecycled ZnO nanoparticles (NPs) recovered from spent Zn-C battery decorated three-dimensional (3D) graphene aerogel hybrid materials has been synthesized via simple eco-friendly synthetic method. The 3D graphene aerogel demonstrate interconnected macroporous networks and the microrecycled ZnO NPs displayed a size of ∼ 40 nm are attached uniformly on the surface of graphene flakes. When being used as NO2 sensors for detecting low concentration of NO2 gas molecules, this macroporous 3D hybrid structure achieved a higher response value along fast response-recovery time characteristics with superior selectivity and repeatability behaviour at room temperature (RT, 20 °C). The elevated NO2 sensing properties for this 3D structure is mainly associated with improved conductivity and porous structure of graphene as well as the interaction between p-type graphene and n-type zinc oxide. Along with the representation of elevated NO2 sensing performance, mechanism behind this sensing phenomenon also discussed in this study. These results and the low-cost, light-weight and eco-friendly fabrication features indicate that the proposed microrecycled ZnO NPs decorated 3D graphene aerogel hybrid sensor is a promising building block for the advancement of high-performance NO2 sensors for real field applications.