Characterization of a hybrid composite of SnO2 nanocrystal-decorated reduced graphene oxide for ppm-level ethanol gas sensing application

Abstract

This paper demonstrated a hybrid composite of tin oxide–reduced graphene oxide (rGO) for ppm-level detection of ethanol vapour. A facile and low-cost method of hydrothermal synthesis was used to construct the SnO₂–rGO hybrid film on a PCB substrate with coil-like interdigital microelectrodes. The presence of small-sized SnO₂ nanocrystals on rGO sheets was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), an X-ray diffractometer (XRD) and Brunauer–Emmett–Teller (BET) measurements. The sensing properties of the SnO₂–rGO hybrid film sensor, including the sensitivity, response–recovery times and repeatability, were investigated by exposing it to various concentrations of ethanol gas varying from 1 ppm to 100 ppm at room temperature. As a result, the presented sensor exhibited a low detection limit of 1 ppm at room temperature, as well as a fast response–recovery time and good repeatability, which outstripped that of pure rGO film sensors. Finally, the possible mechanism of ethanol gas-sensing for the above presented sensor was discussed in detail.