High-performance sulfur dioxide sensing properties of layer-by-layer self-assembled titania-modified graphene hybrid nanocomposite

This paper demonstrates layer-by-layer (LbL) self-assembled titania (TiO2)/graphene film device towards ultralow sulfur dioxide (SO2) gas sensing at room temperature. The as-prepared film was realized through the layer-by-layer alternative deposition of TiO2 nanospheres and graphene oxide (GO) to form a nanostructure, and followed by thermally reducing GO into reduced graphene oxide (rGO). The nanostructural, morphological and compositional properties of TiO2/rGO sample was examined by SEM, TEM, XRD, EDS and Raman spectroscopy. The gas-sensing properties of TiO2/rGO hybrid were investigated at room temperature against low concentration SO2 gas. The sensor in our work exhibited ppb-level detection, rapid response and recovery, good reversibility, selectivity and repeatability for SO2 gas sensing. The possible sensing mechanism for the presented sensor was attributed to the synergistic effect of TiO2 and rGO, as well as special interaction at TiO2/rGO interfaces. This work shows that the fabricated TiO2/rGO film sensor possesses potential applications for SO2 detection with advantages of cost-effective, low power consumption and distinguished sensing abilities.