Reduced graphite oxide/SnO2/Au hybrid nanomaterials for NO2 sensing performance at relatively low operating temperature

Abstract

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.