Zinc Oxide/Reduced Graphene Oxide Nanocomposites for Rapid Detection of Toluene Gas at Room Temperature

In this study, a nanostructured zinc oxide/reduced graphene oxide (ZnO/rGO) composite was deposited on a quartz crystal microbalance (QCM) as a toluene gas sensor at room temperature. A series of ZnO, rGO and ZnO/rGO sensing materials was fabricated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Raman spectroscopy. There was significant efficiency of the ZnO/rGO composite on the sensing performance for toluene. For specific gas fluxes, the nanostructured ZnO/rGO offered sufficient paths and region for vapor diffusion and adsorption. The sensing test results illustrated that the nanostructured ZnO/rGO composite showed significant enhancement in the frequency shifts (△f) for toluene comparing to pure ZnO and rGO. Also, the ZnO/rGO-coated QCM sensor displayed a fast response (both the response and recovery times < 30 s) and reproducibility for sensing toluene gas at room temperature. We believe that the novel insights on ambient temperature gas sensing on nanostructured ZnO/rGO composite could provide a new strategy for preparing a highly efficient sensing materials.