High-Performance Room Temperature Methane Gas Sensor Based on Lead Sulfide/Reduced Graphene Oxide Nanocomposite

Graphene is a monolayer of carbon atoms which shows many exceptional electronic and sensing properties, making it a very promising material for sensing applications. In this paper, lead sulfide nanocrystals (PbS NCs)/reduced graphene oxide (rGO) with different weight ratios were successfully synthesized by a facile method for methane sensing applications. Crystal structure and morphology of synthesized material were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Characterization data demonstrate that rGO nanosheets provide a favorable surface for PbS NCs nucleation. rGO as a high mobility element affects on electrical conductivity, sensor response, and response time of the sensors. Electrical conductivity and methane sensing characteristics were investigated as a function of rGO concentration (0, 1, 2, 3.5, and 5 wt%). The synthesized 3.5 wt% rGO sample exhibited the best methane sensing performance at room temperature. The proposed sensor has shown a good response (more than 40%) at the lower explosive limit of methane.