Sensitive Room-Temperature H2S Gas Sensors Employing SnO2 Quantum Wire/Reduced Graphene Oxide Nanocomposites

Metal oxide/graphene nanocomposites are emerging as one of the promising candidate materials for developing high-performance gas sensors. Here, we demonstrate sensitive room-temperature H2S gas sensors based on SnO2 quantum wires that are anchored on reduced graphene oxide (rGO) nanosheets. Using a one-step colloidal synthesis strategy, the morphology-related quantum confinement of SnO2 can be well-controlled by tuning the reaction time, because of the steric hindrance effect of rGO. The as-synthesized SnO2 quantum wire/rGO nanocomposites are spin-coated onto ceramics substrates without further sintering to construct chemiresistive gas sensors. The optimal sensor response toward 50 ppm of H2S is 33 in 2 s, and it is fully reversible upon H2S release at 22 °C. In addition to the excellent gas adsorption of ultrathin SnO2 quantum wires, the superior sensing performance of SnO2 quantum wire/rGO nanocomposites can be attributed to the enhanced electron transport resulting from the favorable charge transfer of SnO2/rGO interfaces and the superb transport capability of rGO. The easy fabrication and room-temperature operation make our sensors highly attractive for ultrasensitive H2S gas detection with less power consumption.