Graphene Oxide-Loaded SnO2 Quantum Wires with Sub-4 Nanometer Diameters for Low-Temperature H2S Gas Sensing

Chemiresistive gas sensors with low power consumption, high sensitivity, and selectivity are of great significance for low-cost and efficient real-time gas detection. Herein, we present a highly sensitive and selective H2S gas sensor employing thin-layer graphene oxide (GO)-loaded sub-4 nm diameter SnO2 quantum wires (QWs) through a simple mechanical mixing process. The SnO2 QWs with the diameter smaller than 4 nm are decorated uniformly on the surface of the GO, which endows the heterostructure with high charge transport efficiency. The surface activity and adsorbed oxygen species of SnO2, QWs, and the fast charge transfer channel of the GO nanosheet, are confirmed vital to the enhanced gas-sensing properties. As demonstrated, the as fabricated sensors exhibit an optimum gas-sensing performance for ppb-level H2S detection at 70 degrees C. In addition, our sensors are selectively sensitive to H,S and even show fast dynamic response and recovery kinetics toward ppb-level H2S at the high relative humidity of 85%. Moreover, GO-loaded SnO2 QWs with solution processability enable the demonstration of a paper-based flexible H,S sensor for 500 ppb H2S detection with long-term stability. This result helps us to understand that the design and synthesis of 1D SnO, QWs/2D GO nanosheet nanocomposites will provide new paradigms for the future development of H2S-sensitive and selective materials.