Reduced graphite oxide/SnO2/Au hybrid nanomaterials for NO2 sensing performance at relatively low operating temperature
The reduced graphene oxide/SnO2/Au (rGO/SnO2/Au) hybrid nanomaterials have been prepared by a one-step hydrothermal process with a property of gas sensing at a relatively low operating temperature. The structure and morphology characteristics of the resultant product were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The sizes of the Au nanoparticles of rGO/SnO2/Au-1 to rGO/SnO2/Au-4 range from about 12 to 90 nm, respectively. To demonstrate the usage of such hybrid nanomaterials, chemical gas sensors have been fabricated and investigated for NO2 detection. It is found that the rGO/SnO2/Au sensor exhibits much better response/recovery time which is 19/20 s at the optimal operating temperature of 50 °C to 5 ppm NO2, compared with the pure rGO (798/8319 s) and rGO/SnO2 (427/908 s). The enhanced sensing features can be attributed to the heterojunctions with the highly conductive graphene, SnO2 thin film and Au nanoparticles.