▎ 摘　　要

A sub-ppm-level CO gas sensor based on copper oxide (CuO)-decorated graphene hybrid nanocomposite was reported in this paper. The CuO/graphene hierarchical nanocomposite was successfully deposited on a substrate with interdigital microelectrodes via layer-by-layer self-assembly technique. The morphologies, microstructures and compositions of the as-prepared CuO/rGO film were sufficiently characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The gas sensing properties of the CuO/graphene nanocomposite was investigated at room temperature over a wide range concentration of CO gas from 0.25 ppm to 1000 ppm. The experimental results exhibited not only an unprecedented detection abilities, but also fast response and recovery times, excellent repeatability, good stability and selectivity. The superior sensing mechanism for the presented sensor was ascribed to the hierarchical porous nanostructure and the formed heterojunction at the interfaces between CuO nanoflowers and rGO nanosheets. (C) 2017 Elsevier B.V. All rights reserved.