Ultrasensitive and low detection limit of nitrogen dioxide gas sensor based on flower-like ZnO hierarchical nanostructure modified by reduced graphene oxide

Hierarchical rGO/ZnO hybrids with a flower-like morphology of ZnO and flexible rGO sheets were synthesized by a facile solution-processed method. The structures and morphologies of the hybrids were investigated by different kinds of techniques, including X-ray diffraction, field-emission electron scanning microscopy, transmission electron microscopy, and energy dispersive spectroscopy. The gas sensing properties of hierarchical rGO/ZnO hybrids toward nitrogen dioxide were studied via a static system. The response of rGO/ZnO hybrids to 50 ppb NO2 was 12, which was seven times higher than that of pristine ZnO at 100 degrees C. The limit of detection could be achieved as low as 5 ppb. The enhanced sensor response was attributed to the presence of local p-n heterojunctions between rGO sheets and hierarchical structure of ZnO. (C) 2017 Elsevier B.V. All rights reserved.