Synthesis of porous CeO2-SnO2 nanosheets gas sensors with enhanced sensitivity

Two-dimension (2D) CeO2-SnO2 nanosheets with uniform size and small rhombus nanopores were synthesized by the hydrothermal method. The structure of CeO2-SnO2 nanosheets was confirmed by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The gas sensing behaviors of the fabricated sensors were systematically investigated. Under optimum operating temperature (340 °C), the response to 100 ppm ethanol of the CeO2-SnO2 sensor was 44, which was 2 times larger than that of the SnO2 sensor (about 19). The response and recovery time of the CeO2-SnO2 sensor were 25 s and 6 s, while that of the SnO2 sensor were 29 s and 7 s, respectively. The results revealed that porous CeO2-SnO2 nanosheets enhanced the gas sensing properties and shortened the response/recovery time, which were attributed to the porous structure and the effect of the CeO2-doping. In addition, the ethanol sensing mechanism was carefully discussed.